| 1 | // SPDX-License-Identifier: GPL-2.0-only |
| 2 | /* |
| 3 | * Generic hugetlb support. |
| 4 | * (C) Nadia Yvette Chambers, April 2004 |
| 5 | */ |
| 6 | #include <linux/list.h> |
| 7 | #include <linux/init.h> |
| 8 | #include <linux/mm.h> |
| 9 | #include <linux/seq_file.h> |
| 10 | #include <linux/sysctl.h> |
| 11 | #include <linux/highmem.h> |
| 12 | #include <linux/mmu_notifier.h> |
| 13 | #include <linux/nodemask.h> |
| 14 | #include <linux/pagemap.h> |
| 15 | #include <linux/mempolicy.h> |
| 16 | #include <linux/compiler.h> |
| 17 | #include <linux/cpuset.h> |
| 18 | #include <linux/mutex.h> |
| 19 | #include <linux/memblock.h> |
| 20 | #include <linux/sysfs.h> |
| 21 | #include <linux/slab.h> |
| 22 | #include <linux/sched/mm.h> |
| 23 | #include <linux/mmdebug.h> |
| 24 | #include <linux/sched/signal.h> |
| 25 | #include <linux/rmap.h> |
| 26 | #include <linux/string_helpers.h> |
| 27 | #include <linux/swap.h> |
| 28 | #include <linux/swapops.h> |
| 29 | #include <linux/jhash.h> |
| 30 | #include <linux/numa.h> |
| 31 | #include <linux/llist.h> |
| 32 | #include <linux/cma.h> |
| 33 | #include <linux/migrate.h> |
| 34 | #include <linux/nospec.h> |
| 35 | #include <linux/delayacct.h> |
| 36 | #include <linux/memory.h> |
| 37 | |
| 38 | #include <asm/page.h> |
| 39 | #include <asm/pgalloc.h> |
| 40 | #include <asm/tlb.h> |
| 41 | |
| 42 | #include <linux/io.h> |
| 43 | #include <linux/hugetlb.h> |
| 44 | #include <linux/hugetlb_cgroup.h> |
| 45 | #include <linux/node.h> |
| 46 | #include <linux/page_owner.h> |
| 47 | #include "internal.h" |
| 48 | #include "hugetlb_vmemmap.h" |
| 49 | |
| 50 | int hugetlb_max_hstate __read_mostly; |
| 51 | unsigned int default_hstate_idx; |
| 52 | struct hstate hstates[HUGE_MAX_HSTATE]; |
| 53 | |
| 54 | #ifdef CONFIG_CMA |
| 55 | static struct cma *hugetlb_cma[MAX_NUMNODES]; |
| 56 | static unsigned long hugetlb_cma_size_in_node[MAX_NUMNODES] __initdata; |
| 57 | static bool hugetlb_cma_folio(struct folio *folio, unsigned int order) |
| 58 | { |
| 59 | return cma_pages_valid(hugetlb_cma[folio_nid(folio)], &folio->page, |
| 60 | 1 << order); |
| 61 | } |
| 62 | #else |
| 63 | static bool hugetlb_cma_folio(struct folio *folio, unsigned int order) |
| 64 | { |
| 65 | return false; |
| 66 | } |
| 67 | #endif |
| 68 | static unsigned long hugetlb_cma_size __initdata; |
| 69 | |
| 70 | __initdata LIST_HEAD(huge_boot_pages); |
| 71 | |
| 72 | /* for command line parsing */ |
| 73 | static struct hstate * __initdata parsed_hstate; |
| 74 | static unsigned long __initdata default_hstate_max_huge_pages; |
| 75 | static bool __initdata parsed_valid_hugepagesz = true; |
| 76 | static bool __initdata parsed_default_hugepagesz; |
| 77 | static unsigned int default_hugepages_in_node[MAX_NUMNODES] __initdata; |
| 78 | |
| 79 | /* |
| 80 | * Protects updates to hugepage_freelists, hugepage_activelist, nr_huge_pages, |
| 81 | * free_huge_pages, and surplus_huge_pages. |
| 82 | */ |
| 83 | DEFINE_SPINLOCK(hugetlb_lock); |
| 84 | |
| 85 | /* |
| 86 | * Serializes faults on the same logical page. This is used to |
| 87 | * prevent spurious OOMs when the hugepage pool is fully utilized. |
| 88 | */ |
| 89 | static int num_fault_mutexes; |
| 90 | struct mutex *hugetlb_fault_mutex_table ____cacheline_aligned_in_smp; |
| 91 | |
| 92 | /* Forward declaration */ |
| 93 | static int hugetlb_acct_memory(struct hstate *h, long delta); |
| 94 | static void hugetlb_vma_lock_free(struct vm_area_struct *vma); |
| 95 | static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma); |
| 96 | static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma); |
| 97 | static void hugetlb_unshare_pmds(struct vm_area_struct *vma, |
| 98 | unsigned long start, unsigned long end); |
| 99 | |
| 100 | static inline bool subpool_is_free(struct hugepage_subpool *spool) |
| 101 | { |
| 102 | if (spool->count) |
| 103 | return false; |
| 104 | if (spool->max_hpages != -1) |
| 105 | return spool->used_hpages == 0; |
| 106 | if (spool->min_hpages != -1) |
| 107 | return spool->rsv_hpages == spool->min_hpages; |
| 108 | |
| 109 | return true; |
| 110 | } |
| 111 | |
| 112 | static inline void unlock_or_release_subpool(struct hugepage_subpool *spool, |
| 113 | unsigned long irq_flags) |
| 114 | { |
| 115 | spin_unlock_irqrestore(&spool->lock, irq_flags); |
| 116 | |
| 117 | /* If no pages are used, and no other handles to the subpool |
| 118 | * remain, give up any reservations based on minimum size and |
| 119 | * free the subpool */ |
| 120 | if (subpool_is_free(spool)) { |
| 121 | if (spool->min_hpages != -1) |
| 122 | hugetlb_acct_memory(spool->hstate, |
| 123 | -spool->min_hpages); |
| 124 | kfree(spool); |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | struct hugepage_subpool *hugepage_new_subpool(struct hstate *h, long max_hpages, |
| 129 | long min_hpages) |
| 130 | { |
| 131 | struct hugepage_subpool *spool; |
| 132 | |
| 133 | spool = kzalloc(sizeof(*spool), GFP_KERNEL); |
| 134 | if (!spool) |
| 135 | return NULL; |
| 136 | |
| 137 | spin_lock_init(&spool->lock); |
| 138 | spool->count = 1; |
| 139 | spool->max_hpages = max_hpages; |
| 140 | spool->hstate = h; |
| 141 | spool->min_hpages = min_hpages; |
| 142 | |
| 143 | if (min_hpages != -1 && hugetlb_acct_memory(h, min_hpages)) { |
| 144 | kfree(spool); |
| 145 | return NULL; |
| 146 | } |
| 147 | spool->rsv_hpages = min_hpages; |
| 148 | |
| 149 | return spool; |
| 150 | } |
| 151 | |
| 152 | void hugepage_put_subpool(struct hugepage_subpool *spool) |
| 153 | { |
| 154 | unsigned long flags; |
| 155 | |
| 156 | spin_lock_irqsave(&spool->lock, flags); |
| 157 | BUG_ON(!spool->count); |
| 158 | spool->count--; |
| 159 | unlock_or_release_subpool(spool, flags); |
| 160 | } |
| 161 | |
| 162 | /* |
| 163 | * Subpool accounting for allocating and reserving pages. |
| 164 | * Return -ENOMEM if there are not enough resources to satisfy the |
| 165 | * request. Otherwise, return the number of pages by which the |
| 166 | * global pools must be adjusted (upward). The returned value may |
| 167 | * only be different than the passed value (delta) in the case where |
| 168 | * a subpool minimum size must be maintained. |
| 169 | */ |
| 170 | static long hugepage_subpool_get_pages(struct hugepage_subpool *spool, |
| 171 | long delta) |
| 172 | { |
| 173 | long ret = delta; |
| 174 | |
| 175 | if (!spool) |
| 176 | return ret; |
| 177 | |
| 178 | spin_lock_irq(&spool->lock); |
| 179 | |
| 180 | if (spool->max_hpages != -1) { /* maximum size accounting */ |
| 181 | if ((spool->used_hpages + delta) <= spool->max_hpages) |
| 182 | spool->used_hpages += delta; |
| 183 | else { |
| 184 | ret = -ENOMEM; |
| 185 | goto unlock_ret; |
| 186 | } |
| 187 | } |
| 188 | |
| 189 | /* minimum size accounting */ |
| 190 | if (spool->min_hpages != -1 && spool->rsv_hpages) { |
| 191 | if (delta > spool->rsv_hpages) { |
| 192 | /* |
| 193 | * Asking for more reserves than those already taken on |
| 194 | * behalf of subpool. Return difference. |
| 195 | */ |
| 196 | ret = delta - spool->rsv_hpages; |
| 197 | spool->rsv_hpages = 0; |
| 198 | } else { |
| 199 | ret = 0; /* reserves already accounted for */ |
| 200 | spool->rsv_hpages -= delta; |
| 201 | } |
| 202 | } |
| 203 | |
| 204 | unlock_ret: |
| 205 | spin_unlock_irq(&spool->lock); |
| 206 | return ret; |
| 207 | } |
| 208 | |
| 209 | /* |
| 210 | * Subpool accounting for freeing and unreserving pages. |
| 211 | * Return the number of global page reservations that must be dropped. |
| 212 | * The return value may only be different than the passed value (delta) |
| 213 | * in the case where a subpool minimum size must be maintained. |
| 214 | */ |
| 215 | static long hugepage_subpool_put_pages(struct hugepage_subpool *spool, |
| 216 | long delta) |
| 217 | { |
| 218 | long ret = delta; |
| 219 | unsigned long flags; |
| 220 | |
| 221 | if (!spool) |
| 222 | return delta; |
| 223 | |
| 224 | spin_lock_irqsave(&spool->lock, flags); |
| 225 | |
| 226 | if (spool->max_hpages != -1) /* maximum size accounting */ |
| 227 | spool->used_hpages -= delta; |
| 228 | |
| 229 | /* minimum size accounting */ |
| 230 | if (spool->min_hpages != -1 && spool->used_hpages < spool->min_hpages) { |
| 231 | if (spool->rsv_hpages + delta <= spool->min_hpages) |
| 232 | ret = 0; |
| 233 | else |
| 234 | ret = spool->rsv_hpages + delta - spool->min_hpages; |
| 235 | |
| 236 | spool->rsv_hpages += delta; |
| 237 | if (spool->rsv_hpages > spool->min_hpages) |
| 238 | spool->rsv_hpages = spool->min_hpages; |
| 239 | } |
| 240 | |
| 241 | /* |
| 242 | * If hugetlbfs_put_super couldn't free spool due to an outstanding |
| 243 | * quota reference, free it now. |
| 244 | */ |
| 245 | unlock_or_release_subpool(spool, flags); |
| 246 | |
| 247 | return ret; |
| 248 | } |
| 249 | |
| 250 | static inline struct hugepage_subpool *subpool_inode(struct inode *inode) |
| 251 | { |
| 252 | return HUGETLBFS_SB(inode->i_sb)->spool; |
| 253 | } |
| 254 | |
| 255 | static inline struct hugepage_subpool *subpool_vma(struct vm_area_struct *vma) |
| 256 | { |
| 257 | return subpool_inode(file_inode(vma->vm_file)); |
| 258 | } |
| 259 | |
| 260 | /* |
| 261 | * hugetlb vma_lock helper routines |
| 262 | */ |
| 263 | static bool __vma_shareable_lock(struct vm_area_struct *vma) |
| 264 | { |
| 265 | return vma->vm_flags & (VM_MAYSHARE | VM_SHARED) && |
| 266 | vma->vm_private_data; |
| 267 | } |
| 268 | |
| 269 | void hugetlb_vma_lock_read(struct vm_area_struct *vma) |
| 270 | { |
| 271 | if (__vma_shareable_lock(vma)) { |
| 272 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 273 | |
| 274 | down_read(&vma_lock->rw_sema); |
| 275 | } |
| 276 | } |
| 277 | |
| 278 | void hugetlb_vma_unlock_read(struct vm_area_struct *vma) |
| 279 | { |
| 280 | if (__vma_shareable_lock(vma)) { |
| 281 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 282 | |
| 283 | up_read(&vma_lock->rw_sema); |
| 284 | } |
| 285 | } |
| 286 | |
| 287 | void hugetlb_vma_lock_write(struct vm_area_struct *vma) |
| 288 | { |
| 289 | if (__vma_shareable_lock(vma)) { |
| 290 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 291 | |
| 292 | down_write(&vma_lock->rw_sema); |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | void hugetlb_vma_unlock_write(struct vm_area_struct *vma) |
| 297 | { |
| 298 | if (__vma_shareable_lock(vma)) { |
| 299 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 300 | |
| 301 | up_write(&vma_lock->rw_sema); |
| 302 | } |
| 303 | } |
| 304 | |
| 305 | int hugetlb_vma_trylock_write(struct vm_area_struct *vma) |
| 306 | { |
| 307 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 308 | |
| 309 | if (!__vma_shareable_lock(vma)) |
| 310 | return 1; |
| 311 | |
| 312 | return down_write_trylock(&vma_lock->rw_sema); |
| 313 | } |
| 314 | |
| 315 | void hugetlb_vma_assert_locked(struct vm_area_struct *vma) |
| 316 | { |
| 317 | if (__vma_shareable_lock(vma)) { |
| 318 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 319 | |
| 320 | lockdep_assert_held(&vma_lock->rw_sema); |
| 321 | } |
| 322 | } |
| 323 | |
| 324 | void hugetlb_vma_lock_release(struct kref *kref) |
| 325 | { |
| 326 | struct hugetlb_vma_lock *vma_lock = container_of(kref, |
| 327 | struct hugetlb_vma_lock, refs); |
| 328 | |
| 329 | kfree(vma_lock); |
| 330 | } |
| 331 | |
| 332 | static void __hugetlb_vma_unlock_write_put(struct hugetlb_vma_lock *vma_lock) |
| 333 | { |
| 334 | struct vm_area_struct *vma = vma_lock->vma; |
| 335 | |
| 336 | /* |
| 337 | * vma_lock structure may or not be released as a result of put, |
| 338 | * it certainly will no longer be attached to vma so clear pointer. |
| 339 | * Semaphore synchronizes access to vma_lock->vma field. |
| 340 | */ |
| 341 | vma_lock->vma = NULL; |
| 342 | vma->vm_private_data = NULL; |
| 343 | up_write(&vma_lock->rw_sema); |
| 344 | kref_put(&vma_lock->refs, hugetlb_vma_lock_release); |
| 345 | } |
| 346 | |
| 347 | static void __hugetlb_vma_unlock_write_free(struct vm_area_struct *vma) |
| 348 | { |
| 349 | if (__vma_shareable_lock(vma)) { |
| 350 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 351 | |
| 352 | __hugetlb_vma_unlock_write_put(vma_lock); |
| 353 | } |
| 354 | } |
| 355 | |
| 356 | static void hugetlb_vma_lock_free(struct vm_area_struct *vma) |
| 357 | { |
| 358 | /* |
| 359 | * Only present in sharable vmas. |
| 360 | */ |
| 361 | if (!vma || !__vma_shareable_lock(vma)) |
| 362 | return; |
| 363 | |
| 364 | if (vma->vm_private_data) { |
| 365 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 366 | |
| 367 | down_write(&vma_lock->rw_sema); |
| 368 | __hugetlb_vma_unlock_write_put(vma_lock); |
| 369 | } |
| 370 | } |
| 371 | |
| 372 | static void hugetlb_vma_lock_alloc(struct vm_area_struct *vma) |
| 373 | { |
| 374 | struct hugetlb_vma_lock *vma_lock; |
| 375 | |
| 376 | /* Only establish in (flags) sharable vmas */ |
| 377 | if (!vma || !(vma->vm_flags & VM_MAYSHARE)) |
| 378 | return; |
| 379 | |
| 380 | /* Should never get here with non-NULL vm_private_data */ |
| 381 | if (vma->vm_private_data) |
| 382 | return; |
| 383 | |
| 384 | vma_lock = kmalloc(sizeof(*vma_lock), GFP_KERNEL); |
| 385 | if (!vma_lock) { |
| 386 | /* |
| 387 | * If we can not allocate structure, then vma can not |
| 388 | * participate in pmd sharing. This is only a possible |
| 389 | * performance enhancement and memory saving issue. |
| 390 | * However, the lock is also used to synchronize page |
| 391 | * faults with truncation. If the lock is not present, |
| 392 | * unlikely races could leave pages in a file past i_size |
| 393 | * until the file is removed. Warn in the unlikely case of |
| 394 | * allocation failure. |
| 395 | */ |
| 396 | pr_warn_once("HugeTLB: unable to allocate vma specific lock\n"); |
| 397 | return; |
| 398 | } |
| 399 | |
| 400 | kref_init(&vma_lock->refs); |
| 401 | init_rwsem(&vma_lock->rw_sema); |
| 402 | vma_lock->vma = vma; |
| 403 | vma->vm_private_data = vma_lock; |
| 404 | } |
| 405 | |
| 406 | /* Helper that removes a struct file_region from the resv_map cache and returns |
| 407 | * it for use. |
| 408 | */ |
| 409 | static struct file_region * |
| 410 | get_file_region_entry_from_cache(struct resv_map *resv, long from, long to) |
| 411 | { |
| 412 | struct file_region *nrg; |
| 413 | |
| 414 | VM_BUG_ON(resv->region_cache_count <= 0); |
| 415 | |
| 416 | resv->region_cache_count--; |
| 417 | nrg = list_first_entry(&resv->region_cache, struct file_region, link); |
| 418 | list_del(&nrg->link); |
| 419 | |
| 420 | nrg->from = from; |
| 421 | nrg->to = to; |
| 422 | |
| 423 | return nrg; |
| 424 | } |
| 425 | |
| 426 | static void copy_hugetlb_cgroup_uncharge_info(struct file_region *nrg, |
| 427 | struct file_region *rg) |
| 428 | { |
| 429 | #ifdef CONFIG_CGROUP_HUGETLB |
| 430 | nrg->reservation_counter = rg->reservation_counter; |
| 431 | nrg->css = rg->css; |
| 432 | if (rg->css) |
| 433 | css_get(rg->css); |
| 434 | #endif |
| 435 | } |
| 436 | |
| 437 | /* Helper that records hugetlb_cgroup uncharge info. */ |
| 438 | static void record_hugetlb_cgroup_uncharge_info(struct hugetlb_cgroup *h_cg, |
| 439 | struct hstate *h, |
| 440 | struct resv_map *resv, |
| 441 | struct file_region *nrg) |
| 442 | { |
| 443 | #ifdef CONFIG_CGROUP_HUGETLB |
| 444 | if (h_cg) { |
| 445 | nrg->reservation_counter = |
| 446 | &h_cg->rsvd_hugepage[hstate_index(h)]; |
| 447 | nrg->css = &h_cg->css; |
| 448 | /* |
| 449 | * The caller will hold exactly one h_cg->css reference for the |
| 450 | * whole contiguous reservation region. But this area might be |
| 451 | * scattered when there are already some file_regions reside in |
| 452 | * it. As a result, many file_regions may share only one css |
| 453 | * reference. In order to ensure that one file_region must hold |
| 454 | * exactly one h_cg->css reference, we should do css_get for |
| 455 | * each file_region and leave the reference held by caller |
| 456 | * untouched. |
| 457 | */ |
| 458 | css_get(&h_cg->css); |
| 459 | if (!resv->pages_per_hpage) |
| 460 | resv->pages_per_hpage = pages_per_huge_page(h); |
| 461 | /* pages_per_hpage should be the same for all entries in |
| 462 | * a resv_map. |
| 463 | */ |
| 464 | VM_BUG_ON(resv->pages_per_hpage != pages_per_huge_page(h)); |
| 465 | } else { |
| 466 | nrg->reservation_counter = NULL; |
| 467 | nrg->css = NULL; |
| 468 | } |
| 469 | #endif |
| 470 | } |
| 471 | |
| 472 | static void put_uncharge_info(struct file_region *rg) |
| 473 | { |
| 474 | #ifdef CONFIG_CGROUP_HUGETLB |
| 475 | if (rg->css) |
| 476 | css_put(rg->css); |
| 477 | #endif |
| 478 | } |
| 479 | |
| 480 | static bool has_same_uncharge_info(struct file_region *rg, |
| 481 | struct file_region *org) |
| 482 | { |
| 483 | #ifdef CONFIG_CGROUP_HUGETLB |
| 484 | return rg->reservation_counter == org->reservation_counter && |
| 485 | rg->css == org->css; |
| 486 | |
| 487 | #else |
| 488 | return true; |
| 489 | #endif |
| 490 | } |
| 491 | |
| 492 | static void coalesce_file_region(struct resv_map *resv, struct file_region *rg) |
| 493 | { |
| 494 | struct file_region *nrg, *prg; |
| 495 | |
| 496 | prg = list_prev_entry(rg, link); |
| 497 | if (&prg->link != &resv->regions && prg->to == rg->from && |
| 498 | has_same_uncharge_info(prg, rg)) { |
| 499 | prg->to = rg->to; |
| 500 | |
| 501 | list_del(&rg->link); |
| 502 | put_uncharge_info(rg); |
| 503 | kfree(rg); |
| 504 | |
| 505 | rg = prg; |
| 506 | } |
| 507 | |
| 508 | nrg = list_next_entry(rg, link); |
| 509 | if (&nrg->link != &resv->regions && nrg->from == rg->to && |
| 510 | has_same_uncharge_info(nrg, rg)) { |
| 511 | nrg->from = rg->from; |
| 512 | |
| 513 | list_del(&rg->link); |
| 514 | put_uncharge_info(rg); |
| 515 | kfree(rg); |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | static inline long |
| 520 | hugetlb_resv_map_add(struct resv_map *map, struct list_head *rg, long from, |
| 521 | long to, struct hstate *h, struct hugetlb_cgroup *cg, |
| 522 | long *regions_needed) |
| 523 | { |
| 524 | struct file_region *nrg; |
| 525 | |
| 526 | if (!regions_needed) { |
| 527 | nrg = get_file_region_entry_from_cache(map, from, to); |
| 528 | record_hugetlb_cgroup_uncharge_info(cg, h, map, nrg); |
| 529 | list_add(&nrg->link, rg); |
| 530 | coalesce_file_region(map, nrg); |
| 531 | } else |
| 532 | *regions_needed += 1; |
| 533 | |
| 534 | return to - from; |
| 535 | } |
| 536 | |
| 537 | /* |
| 538 | * Must be called with resv->lock held. |
| 539 | * |
| 540 | * Calling this with regions_needed != NULL will count the number of pages |
| 541 | * to be added but will not modify the linked list. And regions_needed will |
| 542 | * indicate the number of file_regions needed in the cache to carry out to add |
| 543 | * the regions for this range. |
| 544 | */ |
| 545 | static long add_reservation_in_range(struct resv_map *resv, long f, long t, |
| 546 | struct hugetlb_cgroup *h_cg, |
| 547 | struct hstate *h, long *regions_needed) |
| 548 | { |
| 549 | long add = 0; |
| 550 | struct list_head *head = &resv->regions; |
| 551 | long last_accounted_offset = f; |
| 552 | struct file_region *iter, *trg = NULL; |
| 553 | struct list_head *rg = NULL; |
| 554 | |
| 555 | if (regions_needed) |
| 556 | *regions_needed = 0; |
| 557 | |
| 558 | /* In this loop, we essentially handle an entry for the range |
| 559 | * [last_accounted_offset, iter->from), at every iteration, with some |
| 560 | * bounds checking. |
| 561 | */ |
| 562 | list_for_each_entry_safe(iter, trg, head, link) { |
| 563 | /* Skip irrelevant regions that start before our range. */ |
| 564 | if (iter->from < f) { |
| 565 | /* If this region ends after the last accounted offset, |
| 566 | * then we need to update last_accounted_offset. |
| 567 | */ |
| 568 | if (iter->to > last_accounted_offset) |
| 569 | last_accounted_offset = iter->to; |
| 570 | continue; |
| 571 | } |
| 572 | |
| 573 | /* When we find a region that starts beyond our range, we've |
| 574 | * finished. |
| 575 | */ |
| 576 | if (iter->from >= t) { |
| 577 | rg = iter->link.prev; |
| 578 | break; |
| 579 | } |
| 580 | |
| 581 | /* Add an entry for last_accounted_offset -> iter->from, and |
| 582 | * update last_accounted_offset. |
| 583 | */ |
| 584 | if (iter->from > last_accounted_offset) |
| 585 | add += hugetlb_resv_map_add(resv, iter->link.prev, |
| 586 | last_accounted_offset, |
| 587 | iter->from, h, h_cg, |
| 588 | regions_needed); |
| 589 | |
| 590 | last_accounted_offset = iter->to; |
| 591 | } |
| 592 | |
| 593 | /* Handle the case where our range extends beyond |
| 594 | * last_accounted_offset. |
| 595 | */ |
| 596 | if (!rg) |
| 597 | rg = head->prev; |
| 598 | if (last_accounted_offset < t) |
| 599 | add += hugetlb_resv_map_add(resv, rg, last_accounted_offset, |
| 600 | t, h, h_cg, regions_needed); |
| 601 | |
| 602 | return add; |
| 603 | } |
| 604 | |
| 605 | /* Must be called with resv->lock acquired. Will drop lock to allocate entries. |
| 606 | */ |
| 607 | static int allocate_file_region_entries(struct resv_map *resv, |
| 608 | int regions_needed) |
| 609 | __must_hold(&resv->lock) |
| 610 | { |
| 611 | LIST_HEAD(allocated_regions); |
| 612 | int to_allocate = 0, i = 0; |
| 613 | struct file_region *trg = NULL, *rg = NULL; |
| 614 | |
| 615 | VM_BUG_ON(regions_needed < 0); |
| 616 | |
| 617 | /* |
| 618 | * Check for sufficient descriptors in the cache to accommodate |
| 619 | * the number of in progress add operations plus regions_needed. |
| 620 | * |
| 621 | * This is a while loop because when we drop the lock, some other call |
| 622 | * to region_add or region_del may have consumed some region_entries, |
| 623 | * so we keep looping here until we finally have enough entries for |
| 624 | * (adds_in_progress + regions_needed). |
| 625 | */ |
| 626 | while (resv->region_cache_count < |
| 627 | (resv->adds_in_progress + regions_needed)) { |
| 628 | to_allocate = resv->adds_in_progress + regions_needed - |
| 629 | resv->region_cache_count; |
| 630 | |
| 631 | /* At this point, we should have enough entries in the cache |
| 632 | * for all the existing adds_in_progress. We should only be |
| 633 | * needing to allocate for regions_needed. |
| 634 | */ |
| 635 | VM_BUG_ON(resv->region_cache_count < resv->adds_in_progress); |
| 636 | |
| 637 | spin_unlock(&resv->lock); |
| 638 | for (i = 0; i < to_allocate; i++) { |
| 639 | trg = kmalloc(sizeof(*trg), GFP_KERNEL); |
| 640 | if (!trg) |
| 641 | goto out_of_memory; |
| 642 | list_add(&trg->link, &allocated_regions); |
| 643 | } |
| 644 | |
| 645 | spin_lock(&resv->lock); |
| 646 | |
| 647 | list_splice(&allocated_regions, &resv->region_cache); |
| 648 | resv->region_cache_count += to_allocate; |
| 649 | } |
| 650 | |
| 651 | return 0; |
| 652 | |
| 653 | out_of_memory: |
| 654 | list_for_each_entry_safe(rg, trg, &allocated_regions, link) { |
| 655 | list_del(&rg->link); |
| 656 | kfree(rg); |
| 657 | } |
| 658 | return -ENOMEM; |
| 659 | } |
| 660 | |
| 661 | /* |
| 662 | * Add the huge page range represented by [f, t) to the reserve |
| 663 | * map. Regions will be taken from the cache to fill in this range. |
| 664 | * Sufficient regions should exist in the cache due to the previous |
| 665 | * call to region_chg with the same range, but in some cases the cache will not |
| 666 | * have sufficient entries due to races with other code doing region_add or |
| 667 | * region_del. The extra needed entries will be allocated. |
| 668 | * |
| 669 | * regions_needed is the out value provided by a previous call to region_chg. |
| 670 | * |
| 671 | * Return the number of new huge pages added to the map. This number is greater |
| 672 | * than or equal to zero. If file_region entries needed to be allocated for |
| 673 | * this operation and we were not able to allocate, it returns -ENOMEM. |
| 674 | * region_add of regions of length 1 never allocate file_regions and cannot |
| 675 | * fail; region_chg will always allocate at least 1 entry and a region_add for |
| 676 | * 1 page will only require at most 1 entry. |
| 677 | */ |
| 678 | static long region_add(struct resv_map *resv, long f, long t, |
| 679 | long in_regions_needed, struct hstate *h, |
| 680 | struct hugetlb_cgroup *h_cg) |
| 681 | { |
| 682 | long add = 0, actual_regions_needed = 0; |
| 683 | |
| 684 | spin_lock(&resv->lock); |
| 685 | retry: |
| 686 | |
| 687 | /* Count how many regions are actually needed to execute this add. */ |
| 688 | add_reservation_in_range(resv, f, t, NULL, NULL, |
| 689 | &actual_regions_needed); |
| 690 | |
| 691 | /* |
| 692 | * Check for sufficient descriptors in the cache to accommodate |
| 693 | * this add operation. Note that actual_regions_needed may be greater |
| 694 | * than in_regions_needed, as the resv_map may have been modified since |
| 695 | * the region_chg call. In this case, we need to make sure that we |
| 696 | * allocate extra entries, such that we have enough for all the |
| 697 | * existing adds_in_progress, plus the excess needed for this |
| 698 | * operation. |
| 699 | */ |
| 700 | if (actual_regions_needed > in_regions_needed && |
| 701 | resv->region_cache_count < |
| 702 | resv->adds_in_progress + |
| 703 | (actual_regions_needed - in_regions_needed)) { |
| 704 | /* region_add operation of range 1 should never need to |
| 705 | * allocate file_region entries. |
| 706 | */ |
| 707 | VM_BUG_ON(t - f <= 1); |
| 708 | |
| 709 | if (allocate_file_region_entries( |
| 710 | resv, actual_regions_needed - in_regions_needed)) { |
| 711 | return -ENOMEM; |
| 712 | } |
| 713 | |
| 714 | goto retry; |
| 715 | } |
| 716 | |
| 717 | add = add_reservation_in_range(resv, f, t, h_cg, h, NULL); |
| 718 | |
| 719 | resv->adds_in_progress -= in_regions_needed; |
| 720 | |
| 721 | spin_unlock(&resv->lock); |
| 722 | return add; |
| 723 | } |
| 724 | |
| 725 | /* |
| 726 | * Examine the existing reserve map and determine how many |
| 727 | * huge pages in the specified range [f, t) are NOT currently |
| 728 | * represented. This routine is called before a subsequent |
| 729 | * call to region_add that will actually modify the reserve |
| 730 | * map to add the specified range [f, t). region_chg does |
| 731 | * not change the number of huge pages represented by the |
| 732 | * map. A number of new file_region structures is added to the cache as a |
| 733 | * placeholder, for the subsequent region_add call to use. At least 1 |
| 734 | * file_region structure is added. |
| 735 | * |
| 736 | * out_regions_needed is the number of regions added to the |
| 737 | * resv->adds_in_progress. This value needs to be provided to a follow up call |
| 738 | * to region_add or region_abort for proper accounting. |
| 739 | * |
| 740 | * Returns the number of huge pages that need to be added to the existing |
| 741 | * reservation map for the range [f, t). This number is greater or equal to |
| 742 | * zero. -ENOMEM is returned if a new file_region structure or cache entry |
| 743 | * is needed and can not be allocated. |
| 744 | */ |
| 745 | static long region_chg(struct resv_map *resv, long f, long t, |
| 746 | long *out_regions_needed) |
| 747 | { |
| 748 | long chg = 0; |
| 749 | |
| 750 | spin_lock(&resv->lock); |
| 751 | |
| 752 | /* Count how many hugepages in this range are NOT represented. */ |
| 753 | chg = add_reservation_in_range(resv, f, t, NULL, NULL, |
| 754 | out_regions_needed); |
| 755 | |
| 756 | if (*out_regions_needed == 0) |
| 757 | *out_regions_needed = 1; |
| 758 | |
| 759 | if (allocate_file_region_entries(resv, *out_regions_needed)) |
| 760 | return -ENOMEM; |
| 761 | |
| 762 | resv->adds_in_progress += *out_regions_needed; |
| 763 | |
| 764 | spin_unlock(&resv->lock); |
| 765 | return chg; |
| 766 | } |
| 767 | |
| 768 | /* |
| 769 | * Abort the in progress add operation. The adds_in_progress field |
| 770 | * of the resv_map keeps track of the operations in progress between |
| 771 | * calls to region_chg and region_add. Operations are sometimes |
| 772 | * aborted after the call to region_chg. In such cases, region_abort |
| 773 | * is called to decrement the adds_in_progress counter. regions_needed |
| 774 | * is the value returned by the region_chg call, it is used to decrement |
| 775 | * the adds_in_progress counter. |
| 776 | * |
| 777 | * NOTE: The range arguments [f, t) are not needed or used in this |
| 778 | * routine. They are kept to make reading the calling code easier as |
| 779 | * arguments will match the associated region_chg call. |
| 780 | */ |
| 781 | static void region_abort(struct resv_map *resv, long f, long t, |
| 782 | long regions_needed) |
| 783 | { |
| 784 | spin_lock(&resv->lock); |
| 785 | VM_BUG_ON(!resv->region_cache_count); |
| 786 | resv->adds_in_progress -= regions_needed; |
| 787 | spin_unlock(&resv->lock); |
| 788 | } |
| 789 | |
| 790 | /* |
| 791 | * Delete the specified range [f, t) from the reserve map. If the |
| 792 | * t parameter is LONG_MAX, this indicates that ALL regions after f |
| 793 | * should be deleted. Locate the regions which intersect [f, t) |
| 794 | * and either trim, delete or split the existing regions. |
| 795 | * |
| 796 | * Returns the number of huge pages deleted from the reserve map. |
| 797 | * In the normal case, the return value is zero or more. In the |
| 798 | * case where a region must be split, a new region descriptor must |
| 799 | * be allocated. If the allocation fails, -ENOMEM will be returned. |
| 800 | * NOTE: If the parameter t == LONG_MAX, then we will never split |
| 801 | * a region and possibly return -ENOMEM. Callers specifying |
| 802 | * t == LONG_MAX do not need to check for -ENOMEM error. |
| 803 | */ |
| 804 | static long region_del(struct resv_map *resv, long f, long t) |
| 805 | { |
| 806 | struct list_head *head = &resv->regions; |
| 807 | struct file_region *rg, *trg; |
| 808 | struct file_region *nrg = NULL; |
| 809 | long del = 0; |
| 810 | |
| 811 | retry: |
| 812 | spin_lock(&resv->lock); |
| 813 | list_for_each_entry_safe(rg, trg, head, link) { |
| 814 | /* |
| 815 | * Skip regions before the range to be deleted. file_region |
| 816 | * ranges are normally of the form [from, to). However, there |
| 817 | * may be a "placeholder" entry in the map which is of the form |
| 818 | * (from, to) with from == to. Check for placeholder entries |
| 819 | * at the beginning of the range to be deleted. |
| 820 | */ |
| 821 | if (rg->to <= f && (rg->to != rg->from || rg->to != f)) |
| 822 | continue; |
| 823 | |
| 824 | if (rg->from >= t) |
| 825 | break; |
| 826 | |
| 827 | if (f > rg->from && t < rg->to) { /* Must split region */ |
| 828 | /* |
| 829 | * Check for an entry in the cache before dropping |
| 830 | * lock and attempting allocation. |
| 831 | */ |
| 832 | if (!nrg && |
| 833 | resv->region_cache_count > resv->adds_in_progress) { |
| 834 | nrg = list_first_entry(&resv->region_cache, |
| 835 | struct file_region, |
| 836 | link); |
| 837 | list_del(&nrg->link); |
| 838 | resv->region_cache_count--; |
| 839 | } |
| 840 | |
| 841 | if (!nrg) { |
| 842 | spin_unlock(&resv->lock); |
| 843 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| 844 | if (!nrg) |
| 845 | return -ENOMEM; |
| 846 | goto retry; |
| 847 | } |
| 848 | |
| 849 | del += t - f; |
| 850 | hugetlb_cgroup_uncharge_file_region( |
| 851 | resv, rg, t - f, false); |
| 852 | |
| 853 | /* New entry for end of split region */ |
| 854 | nrg->from = t; |
| 855 | nrg->to = rg->to; |
| 856 | |
| 857 | copy_hugetlb_cgroup_uncharge_info(nrg, rg); |
| 858 | |
| 859 | INIT_LIST_HEAD(&nrg->link); |
| 860 | |
| 861 | /* Original entry is trimmed */ |
| 862 | rg->to = f; |
| 863 | |
| 864 | list_add(&nrg->link, &rg->link); |
| 865 | nrg = NULL; |
| 866 | break; |
| 867 | } |
| 868 | |
| 869 | if (f <= rg->from && t >= rg->to) { /* Remove entire region */ |
| 870 | del += rg->to - rg->from; |
| 871 | hugetlb_cgroup_uncharge_file_region(resv, rg, |
| 872 | rg->to - rg->from, true); |
| 873 | list_del(&rg->link); |
| 874 | kfree(rg); |
| 875 | continue; |
| 876 | } |
| 877 | |
| 878 | if (f <= rg->from) { /* Trim beginning of region */ |
| 879 | hugetlb_cgroup_uncharge_file_region(resv, rg, |
| 880 | t - rg->from, false); |
| 881 | |
| 882 | del += t - rg->from; |
| 883 | rg->from = t; |
| 884 | } else { /* Trim end of region */ |
| 885 | hugetlb_cgroup_uncharge_file_region(resv, rg, |
| 886 | rg->to - f, false); |
| 887 | |
| 888 | del += rg->to - f; |
| 889 | rg->to = f; |
| 890 | } |
| 891 | } |
| 892 | |
| 893 | spin_unlock(&resv->lock); |
| 894 | kfree(nrg); |
| 895 | return del; |
| 896 | } |
| 897 | |
| 898 | /* |
| 899 | * A rare out of memory error was encountered which prevented removal of |
| 900 | * the reserve map region for a page. The huge page itself was free'ed |
| 901 | * and removed from the page cache. This routine will adjust the subpool |
| 902 | * usage count, and the global reserve count if needed. By incrementing |
| 903 | * these counts, the reserve map entry which could not be deleted will |
| 904 | * appear as a "reserved" entry instead of simply dangling with incorrect |
| 905 | * counts. |
| 906 | */ |
| 907 | void hugetlb_fix_reserve_counts(struct inode *inode) |
| 908 | { |
| 909 | struct hugepage_subpool *spool = subpool_inode(inode); |
| 910 | long rsv_adjust; |
| 911 | bool reserved = false; |
| 912 | |
| 913 | rsv_adjust = hugepage_subpool_get_pages(spool, 1); |
| 914 | if (rsv_adjust > 0) { |
| 915 | struct hstate *h = hstate_inode(inode); |
| 916 | |
| 917 | if (!hugetlb_acct_memory(h, 1)) |
| 918 | reserved = true; |
| 919 | } else if (!rsv_adjust) { |
| 920 | reserved = true; |
| 921 | } |
| 922 | |
| 923 | if (!reserved) |
| 924 | pr_warn("hugetlb: Huge Page Reserved count may go negative.\n"); |
| 925 | } |
| 926 | |
| 927 | /* |
| 928 | * Count and return the number of huge pages in the reserve map |
| 929 | * that intersect with the range [f, t). |
| 930 | */ |
| 931 | static long region_count(struct resv_map *resv, long f, long t) |
| 932 | { |
| 933 | struct list_head *head = &resv->regions; |
| 934 | struct file_region *rg; |
| 935 | long chg = 0; |
| 936 | |
| 937 | spin_lock(&resv->lock); |
| 938 | /* Locate each segment we overlap with, and count that overlap. */ |
| 939 | list_for_each_entry(rg, head, link) { |
| 940 | long seg_from; |
| 941 | long seg_to; |
| 942 | |
| 943 | if (rg->to <= f) |
| 944 | continue; |
| 945 | if (rg->from >= t) |
| 946 | break; |
| 947 | |
| 948 | seg_from = max(rg->from, f); |
| 949 | seg_to = min(rg->to, t); |
| 950 | |
| 951 | chg += seg_to - seg_from; |
| 952 | } |
| 953 | spin_unlock(&resv->lock); |
| 954 | |
| 955 | return chg; |
| 956 | } |
| 957 | |
| 958 | /* |
| 959 | * Convert the address within this vma to the page offset within |
| 960 | * the mapping, in pagecache page units; huge pages here. |
| 961 | */ |
| 962 | static pgoff_t vma_hugecache_offset(struct hstate *h, |
| 963 | struct vm_area_struct *vma, unsigned long address) |
| 964 | { |
| 965 | return ((address - vma->vm_start) >> huge_page_shift(h)) + |
| 966 | (vma->vm_pgoff >> huge_page_order(h)); |
| 967 | } |
| 968 | |
| 969 | pgoff_t linear_hugepage_index(struct vm_area_struct *vma, |
| 970 | unsigned long address) |
| 971 | { |
| 972 | return vma_hugecache_offset(hstate_vma(vma), vma, address); |
| 973 | } |
| 974 | EXPORT_SYMBOL_GPL(linear_hugepage_index); |
| 975 | |
| 976 | /* |
| 977 | * Return the size of the pages allocated when backing a VMA. In the majority |
| 978 | * cases this will be same size as used by the page table entries. |
| 979 | */ |
| 980 | unsigned long vma_kernel_pagesize(struct vm_area_struct *vma) |
| 981 | { |
| 982 | if (vma->vm_ops && vma->vm_ops->pagesize) |
| 983 | return vma->vm_ops->pagesize(vma); |
| 984 | return PAGE_SIZE; |
| 985 | } |
| 986 | EXPORT_SYMBOL_GPL(vma_kernel_pagesize); |
| 987 | |
| 988 | /* |
| 989 | * Return the page size being used by the MMU to back a VMA. In the majority |
| 990 | * of cases, the page size used by the kernel matches the MMU size. On |
| 991 | * architectures where it differs, an architecture-specific 'strong' |
| 992 | * version of this symbol is required. |
| 993 | */ |
| 994 | __weak unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) |
| 995 | { |
| 996 | return vma_kernel_pagesize(vma); |
| 997 | } |
| 998 | |
| 999 | /* |
| 1000 | * Flags for MAP_PRIVATE reservations. These are stored in the bottom |
| 1001 | * bits of the reservation map pointer, which are always clear due to |
| 1002 | * alignment. |
| 1003 | */ |
| 1004 | #define HPAGE_RESV_OWNER (1UL << 0) |
| 1005 | #define HPAGE_RESV_UNMAPPED (1UL << 1) |
| 1006 | #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
| 1007 | |
| 1008 | /* |
| 1009 | * These helpers are used to track how many pages are reserved for |
| 1010 | * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
| 1011 | * is guaranteed to have their future faults succeed. |
| 1012 | * |
| 1013 | * With the exception of hugetlb_dup_vma_private() which is called at fork(), |
| 1014 | * the reserve counters are updated with the hugetlb_lock held. It is safe |
| 1015 | * to reset the VMA at fork() time as it is not in use yet and there is no |
| 1016 | * chance of the global counters getting corrupted as a result of the values. |
| 1017 | * |
| 1018 | * The private mapping reservation is represented in a subtly different |
| 1019 | * manner to a shared mapping. A shared mapping has a region map associated |
| 1020 | * with the underlying file, this region map represents the backing file |
| 1021 | * pages which have ever had a reservation assigned which this persists even |
| 1022 | * after the page is instantiated. A private mapping has a region map |
| 1023 | * associated with the original mmap which is attached to all VMAs which |
| 1024 | * reference it, this region map represents those offsets which have consumed |
| 1025 | * reservation ie. where pages have been instantiated. |
| 1026 | */ |
| 1027 | static unsigned long get_vma_private_data(struct vm_area_struct *vma) |
| 1028 | { |
| 1029 | return (unsigned long)vma->vm_private_data; |
| 1030 | } |
| 1031 | |
| 1032 | static void set_vma_private_data(struct vm_area_struct *vma, |
| 1033 | unsigned long value) |
| 1034 | { |
| 1035 | vma->vm_private_data = (void *)value; |
| 1036 | } |
| 1037 | |
| 1038 | static void |
| 1039 | resv_map_set_hugetlb_cgroup_uncharge_info(struct resv_map *resv_map, |
| 1040 | struct hugetlb_cgroup *h_cg, |
| 1041 | struct hstate *h) |
| 1042 | { |
| 1043 | #ifdef CONFIG_CGROUP_HUGETLB |
| 1044 | if (!h_cg || !h) { |
| 1045 | resv_map->reservation_counter = NULL; |
| 1046 | resv_map->pages_per_hpage = 0; |
| 1047 | resv_map->css = NULL; |
| 1048 | } else { |
| 1049 | resv_map->reservation_counter = |
| 1050 | &h_cg->rsvd_hugepage[hstate_index(h)]; |
| 1051 | resv_map->pages_per_hpage = pages_per_huge_page(h); |
| 1052 | resv_map->css = &h_cg->css; |
| 1053 | } |
| 1054 | #endif |
| 1055 | } |
| 1056 | |
| 1057 | struct resv_map *resv_map_alloc(void) |
| 1058 | { |
| 1059 | struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); |
| 1060 | struct file_region *rg = kmalloc(sizeof(*rg), GFP_KERNEL); |
| 1061 | |
| 1062 | if (!resv_map || !rg) { |
| 1063 | kfree(resv_map); |
| 1064 | kfree(rg); |
| 1065 | return NULL; |
| 1066 | } |
| 1067 | |
| 1068 | kref_init(&resv_map->refs); |
| 1069 | spin_lock_init(&resv_map->lock); |
| 1070 | INIT_LIST_HEAD(&resv_map->regions); |
| 1071 | |
| 1072 | resv_map->adds_in_progress = 0; |
| 1073 | /* |
| 1074 | * Initialize these to 0. On shared mappings, 0's here indicate these |
| 1075 | * fields don't do cgroup accounting. On private mappings, these will be |
| 1076 | * re-initialized to the proper values, to indicate that hugetlb cgroup |
| 1077 | * reservations are to be un-charged from here. |
| 1078 | */ |
| 1079 | resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, NULL, NULL); |
| 1080 | |
| 1081 | INIT_LIST_HEAD(&resv_map->region_cache); |
| 1082 | list_add(&rg->link, &resv_map->region_cache); |
| 1083 | resv_map->region_cache_count = 1; |
| 1084 | |
| 1085 | return resv_map; |
| 1086 | } |
| 1087 | |
| 1088 | void resv_map_release(struct kref *ref) |
| 1089 | { |
| 1090 | struct resv_map *resv_map = container_of(ref, struct resv_map, refs); |
| 1091 | struct list_head *head = &resv_map->region_cache; |
| 1092 | struct file_region *rg, *trg; |
| 1093 | |
| 1094 | /* Clear out any active regions before we release the map. */ |
| 1095 | region_del(resv_map, 0, LONG_MAX); |
| 1096 | |
| 1097 | /* ... and any entries left in the cache */ |
| 1098 | list_for_each_entry_safe(rg, trg, head, link) { |
| 1099 | list_del(&rg->link); |
| 1100 | kfree(rg); |
| 1101 | } |
| 1102 | |
| 1103 | VM_BUG_ON(resv_map->adds_in_progress); |
| 1104 | |
| 1105 | kfree(resv_map); |
| 1106 | } |
| 1107 | |
| 1108 | static inline struct resv_map *inode_resv_map(struct inode *inode) |
| 1109 | { |
| 1110 | /* |
| 1111 | * At inode evict time, i_mapping may not point to the original |
| 1112 | * address space within the inode. This original address space |
| 1113 | * contains the pointer to the resv_map. So, always use the |
| 1114 | * address space embedded within the inode. |
| 1115 | * The VERY common case is inode->mapping == &inode->i_data but, |
| 1116 | * this may not be true for device special inodes. |
| 1117 | */ |
| 1118 | return (struct resv_map *)(&inode->i_data)->private_data; |
| 1119 | } |
| 1120 | |
| 1121 | static struct resv_map *vma_resv_map(struct vm_area_struct *vma) |
| 1122 | { |
| 1123 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| 1124 | if (vma->vm_flags & VM_MAYSHARE) { |
| 1125 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 1126 | struct inode *inode = mapping->host; |
| 1127 | |
| 1128 | return inode_resv_map(inode); |
| 1129 | |
| 1130 | } else { |
| 1131 | return (struct resv_map *)(get_vma_private_data(vma) & |
| 1132 | ~HPAGE_RESV_MASK); |
| 1133 | } |
| 1134 | } |
| 1135 | |
| 1136 | static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) |
| 1137 | { |
| 1138 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| 1139 | VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma); |
| 1140 | |
| 1141 | set_vma_private_data(vma, (get_vma_private_data(vma) & |
| 1142 | HPAGE_RESV_MASK) | (unsigned long)map); |
| 1143 | } |
| 1144 | |
| 1145 | static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) |
| 1146 | { |
| 1147 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| 1148 | VM_BUG_ON_VMA(vma->vm_flags & VM_MAYSHARE, vma); |
| 1149 | |
| 1150 | set_vma_private_data(vma, get_vma_private_data(vma) | flags); |
| 1151 | } |
| 1152 | |
| 1153 | static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
| 1154 | { |
| 1155 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| 1156 | |
| 1157 | return (get_vma_private_data(vma) & flag) != 0; |
| 1158 | } |
| 1159 | |
| 1160 | void hugetlb_dup_vma_private(struct vm_area_struct *vma) |
| 1161 | { |
| 1162 | VM_BUG_ON_VMA(!is_vm_hugetlb_page(vma), vma); |
| 1163 | /* |
| 1164 | * Clear vm_private_data |
| 1165 | * - For shared mappings this is a per-vma semaphore that may be |
| 1166 | * allocated in a subsequent call to hugetlb_vm_op_open. |
| 1167 | * Before clearing, make sure pointer is not associated with vma |
| 1168 | * as this will leak the structure. This is the case when called |
| 1169 | * via clear_vma_resv_huge_pages() and hugetlb_vm_op_open has already |
| 1170 | * been called to allocate a new structure. |
| 1171 | * - For MAP_PRIVATE mappings, this is the reserve map which does |
| 1172 | * not apply to children. Faults generated by the children are |
| 1173 | * not guaranteed to succeed, even if read-only. |
| 1174 | */ |
| 1175 | if (vma->vm_flags & VM_MAYSHARE) { |
| 1176 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 1177 | |
| 1178 | if (vma_lock && vma_lock->vma != vma) |
| 1179 | vma->vm_private_data = NULL; |
| 1180 | } else |
| 1181 | vma->vm_private_data = NULL; |
| 1182 | } |
| 1183 | |
| 1184 | /* |
| 1185 | * Reset and decrement one ref on hugepage private reservation. |
| 1186 | * Called with mm->mmap_lock writer semaphore held. |
| 1187 | * This function should be only used by move_vma() and operate on |
| 1188 | * same sized vma. It should never come here with last ref on the |
| 1189 | * reservation. |
| 1190 | */ |
| 1191 | void clear_vma_resv_huge_pages(struct vm_area_struct *vma) |
| 1192 | { |
| 1193 | /* |
| 1194 | * Clear the old hugetlb private page reservation. |
| 1195 | * It has already been transferred to new_vma. |
| 1196 | * |
| 1197 | * During a mremap() operation of a hugetlb vma we call move_vma() |
| 1198 | * which copies vma into new_vma and unmaps vma. After the copy |
| 1199 | * operation both new_vma and vma share a reference to the resv_map |
| 1200 | * struct, and at that point vma is about to be unmapped. We don't |
| 1201 | * want to return the reservation to the pool at unmap of vma because |
| 1202 | * the reservation still lives on in new_vma, so simply decrement the |
| 1203 | * ref here and remove the resv_map reference from this vma. |
| 1204 | */ |
| 1205 | struct resv_map *reservations = vma_resv_map(vma); |
| 1206 | |
| 1207 | if (reservations && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| 1208 | resv_map_put_hugetlb_cgroup_uncharge_info(reservations); |
| 1209 | kref_put(&reservations->refs, resv_map_release); |
| 1210 | } |
| 1211 | |
| 1212 | hugetlb_dup_vma_private(vma); |
| 1213 | } |
| 1214 | |
| 1215 | /* Returns true if the VMA has associated reserve pages */ |
| 1216 | static bool vma_has_reserves(struct vm_area_struct *vma, long chg) |
| 1217 | { |
| 1218 | if (vma->vm_flags & VM_NORESERVE) { |
| 1219 | /* |
| 1220 | * This address is already reserved by other process(chg == 0), |
| 1221 | * so, we should decrement reserved count. Without decrementing, |
| 1222 | * reserve count remains after releasing inode, because this |
| 1223 | * allocated page will go into page cache and is regarded as |
| 1224 | * coming from reserved pool in releasing step. Currently, we |
| 1225 | * don't have any other solution to deal with this situation |
| 1226 | * properly, so add work-around here. |
| 1227 | */ |
| 1228 | if (vma->vm_flags & VM_MAYSHARE && chg == 0) |
| 1229 | return true; |
| 1230 | else |
| 1231 | return false; |
| 1232 | } |
| 1233 | |
| 1234 | /* Shared mappings always use reserves */ |
| 1235 | if (vma->vm_flags & VM_MAYSHARE) { |
| 1236 | /* |
| 1237 | * We know VM_NORESERVE is not set. Therefore, there SHOULD |
| 1238 | * be a region map for all pages. The only situation where |
| 1239 | * there is no region map is if a hole was punched via |
| 1240 | * fallocate. In this case, there really are no reserves to |
| 1241 | * use. This situation is indicated if chg != 0. |
| 1242 | */ |
| 1243 | if (chg) |
| 1244 | return false; |
| 1245 | else |
| 1246 | return true; |
| 1247 | } |
| 1248 | |
| 1249 | /* |
| 1250 | * Only the process that called mmap() has reserves for |
| 1251 | * private mappings. |
| 1252 | */ |
| 1253 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| 1254 | /* |
| 1255 | * Like the shared case above, a hole punch or truncate |
| 1256 | * could have been performed on the private mapping. |
| 1257 | * Examine the value of chg to determine if reserves |
| 1258 | * actually exist or were previously consumed. |
| 1259 | * Very Subtle - The value of chg comes from a previous |
| 1260 | * call to vma_needs_reserves(). The reserve map for |
| 1261 | * private mappings has different (opposite) semantics |
| 1262 | * than that of shared mappings. vma_needs_reserves() |
| 1263 | * has already taken this difference in semantics into |
| 1264 | * account. Therefore, the meaning of chg is the same |
| 1265 | * as in the shared case above. Code could easily be |
| 1266 | * combined, but keeping it separate draws attention to |
| 1267 | * subtle differences. |
| 1268 | */ |
| 1269 | if (chg) |
| 1270 | return false; |
| 1271 | else |
| 1272 | return true; |
| 1273 | } |
| 1274 | |
| 1275 | return false; |
| 1276 | } |
| 1277 | |
| 1278 | static void enqueue_hugetlb_folio(struct hstate *h, struct folio *folio) |
| 1279 | { |
| 1280 | int nid = folio_nid(folio); |
| 1281 | |
| 1282 | lockdep_assert_held(&hugetlb_lock); |
| 1283 | VM_BUG_ON_FOLIO(folio_ref_count(folio), folio); |
| 1284 | |
| 1285 | list_move(&folio->lru, &h->hugepage_freelists[nid]); |
| 1286 | h->free_huge_pages++; |
| 1287 | h->free_huge_pages_node[nid]++; |
| 1288 | folio_set_hugetlb_freed(folio); |
| 1289 | } |
| 1290 | |
| 1291 | static struct page *dequeue_huge_page_node_exact(struct hstate *h, int nid) |
| 1292 | { |
| 1293 | struct page *page; |
| 1294 | bool pin = !!(current->flags & PF_MEMALLOC_PIN); |
| 1295 | |
| 1296 | lockdep_assert_held(&hugetlb_lock); |
| 1297 | list_for_each_entry(page, &h->hugepage_freelists[nid], lru) { |
| 1298 | if (pin && !is_longterm_pinnable_page(page)) |
| 1299 | continue; |
| 1300 | |
| 1301 | if (PageHWPoison(page)) |
| 1302 | continue; |
| 1303 | |
| 1304 | list_move(&page->lru, &h->hugepage_activelist); |
| 1305 | set_page_refcounted(page); |
| 1306 | ClearHPageFreed(page); |
| 1307 | h->free_huge_pages--; |
| 1308 | h->free_huge_pages_node[nid]--; |
| 1309 | return page; |
| 1310 | } |
| 1311 | |
| 1312 | return NULL; |
| 1313 | } |
| 1314 | |
| 1315 | static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask, int nid, |
| 1316 | nodemask_t *nmask) |
| 1317 | { |
| 1318 | unsigned int cpuset_mems_cookie; |
| 1319 | struct zonelist *zonelist; |
| 1320 | struct zone *zone; |
| 1321 | struct zoneref *z; |
| 1322 | int node = NUMA_NO_NODE; |
| 1323 | |
| 1324 | zonelist = node_zonelist(nid, gfp_mask); |
| 1325 | |
| 1326 | retry_cpuset: |
| 1327 | cpuset_mems_cookie = read_mems_allowed_begin(); |
| 1328 | for_each_zone_zonelist_nodemask(zone, z, zonelist, gfp_zone(gfp_mask), nmask) { |
| 1329 | struct page *page; |
| 1330 | |
| 1331 | if (!cpuset_zone_allowed(zone, gfp_mask)) |
| 1332 | continue; |
| 1333 | /* |
| 1334 | * no need to ask again on the same node. Pool is node rather than |
| 1335 | * zone aware |
| 1336 | */ |
| 1337 | if (zone_to_nid(zone) == node) |
| 1338 | continue; |
| 1339 | node = zone_to_nid(zone); |
| 1340 | |
| 1341 | page = dequeue_huge_page_node_exact(h, node); |
| 1342 | if (page) |
| 1343 | return page; |
| 1344 | } |
| 1345 | if (unlikely(read_mems_allowed_retry(cpuset_mems_cookie))) |
| 1346 | goto retry_cpuset; |
| 1347 | |
| 1348 | return NULL; |
| 1349 | } |
| 1350 | |
| 1351 | static unsigned long available_huge_pages(struct hstate *h) |
| 1352 | { |
| 1353 | return h->free_huge_pages - h->resv_huge_pages; |
| 1354 | } |
| 1355 | |
| 1356 | static struct page *dequeue_huge_page_vma(struct hstate *h, |
| 1357 | struct vm_area_struct *vma, |
| 1358 | unsigned long address, int avoid_reserve, |
| 1359 | long chg) |
| 1360 | { |
| 1361 | struct page *page = NULL; |
| 1362 | struct mempolicy *mpol; |
| 1363 | gfp_t gfp_mask; |
| 1364 | nodemask_t *nodemask; |
| 1365 | int nid; |
| 1366 | |
| 1367 | /* |
| 1368 | * A child process with MAP_PRIVATE mappings created by their parent |
| 1369 | * have no page reserves. This check ensures that reservations are |
| 1370 | * not "stolen". The child may still get SIGKILLed |
| 1371 | */ |
| 1372 | if (!vma_has_reserves(vma, chg) && !available_huge_pages(h)) |
| 1373 | goto err; |
| 1374 | |
| 1375 | /* If reserves cannot be used, ensure enough pages are in the pool */ |
| 1376 | if (avoid_reserve && !available_huge_pages(h)) |
| 1377 | goto err; |
| 1378 | |
| 1379 | gfp_mask = htlb_alloc_mask(h); |
| 1380 | nid = huge_node(vma, address, gfp_mask, &mpol, &nodemask); |
| 1381 | |
| 1382 | if (mpol_is_preferred_many(mpol)) { |
| 1383 | page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); |
| 1384 | |
| 1385 | /* Fallback to all nodes if page==NULL */ |
| 1386 | nodemask = NULL; |
| 1387 | } |
| 1388 | |
| 1389 | if (!page) |
| 1390 | page = dequeue_huge_page_nodemask(h, gfp_mask, nid, nodemask); |
| 1391 | |
| 1392 | if (page && !avoid_reserve && vma_has_reserves(vma, chg)) { |
| 1393 | SetHPageRestoreReserve(page); |
| 1394 | h->resv_huge_pages--; |
| 1395 | } |
| 1396 | |
| 1397 | mpol_cond_put(mpol); |
| 1398 | return page; |
| 1399 | |
| 1400 | err: |
| 1401 | return NULL; |
| 1402 | } |
| 1403 | |
| 1404 | /* |
| 1405 | * common helper functions for hstate_next_node_to_{alloc|free}. |
| 1406 | * We may have allocated or freed a huge page based on a different |
| 1407 | * nodes_allowed previously, so h->next_node_to_{alloc|free} might |
| 1408 | * be outside of *nodes_allowed. Ensure that we use an allowed |
| 1409 | * node for alloc or free. |
| 1410 | */ |
| 1411 | static int next_node_allowed(int nid, nodemask_t *nodes_allowed) |
| 1412 | { |
| 1413 | nid = next_node_in(nid, *nodes_allowed); |
| 1414 | VM_BUG_ON(nid >= MAX_NUMNODES); |
| 1415 | |
| 1416 | return nid; |
| 1417 | } |
| 1418 | |
| 1419 | static int get_valid_node_allowed(int nid, nodemask_t *nodes_allowed) |
| 1420 | { |
| 1421 | if (!node_isset(nid, *nodes_allowed)) |
| 1422 | nid = next_node_allowed(nid, nodes_allowed); |
| 1423 | return nid; |
| 1424 | } |
| 1425 | |
| 1426 | /* |
| 1427 | * returns the previously saved node ["this node"] from which to |
| 1428 | * allocate a persistent huge page for the pool and advance the |
| 1429 | * next node from which to allocate, handling wrap at end of node |
| 1430 | * mask. |
| 1431 | */ |
| 1432 | static int hstate_next_node_to_alloc(struct hstate *h, |
| 1433 | nodemask_t *nodes_allowed) |
| 1434 | { |
| 1435 | int nid; |
| 1436 | |
| 1437 | VM_BUG_ON(!nodes_allowed); |
| 1438 | |
| 1439 | nid = get_valid_node_allowed(h->next_nid_to_alloc, nodes_allowed); |
| 1440 | h->next_nid_to_alloc = next_node_allowed(nid, nodes_allowed); |
| 1441 | |
| 1442 | return nid; |
| 1443 | } |
| 1444 | |
| 1445 | /* |
| 1446 | * helper for remove_pool_huge_page() - return the previously saved |
| 1447 | * node ["this node"] from which to free a huge page. Advance the |
| 1448 | * next node id whether or not we find a free huge page to free so |
| 1449 | * that the next attempt to free addresses the next node. |
| 1450 | */ |
| 1451 | static int hstate_next_node_to_free(struct hstate *h, nodemask_t *nodes_allowed) |
| 1452 | { |
| 1453 | int nid; |
| 1454 | |
| 1455 | VM_BUG_ON(!nodes_allowed); |
| 1456 | |
| 1457 | nid = get_valid_node_allowed(h->next_nid_to_free, nodes_allowed); |
| 1458 | h->next_nid_to_free = next_node_allowed(nid, nodes_allowed); |
| 1459 | |
| 1460 | return nid; |
| 1461 | } |
| 1462 | |
| 1463 | #define for_each_node_mask_to_alloc(hs, nr_nodes, node, mask) \ |
| 1464 | for (nr_nodes = nodes_weight(*mask); \ |
| 1465 | nr_nodes > 0 && \ |
| 1466 | ((node = hstate_next_node_to_alloc(hs, mask)) || 1); \ |
| 1467 | nr_nodes--) |
| 1468 | |
| 1469 | #define for_each_node_mask_to_free(hs, nr_nodes, node, mask) \ |
| 1470 | for (nr_nodes = nodes_weight(*mask); \ |
| 1471 | nr_nodes > 0 && \ |
| 1472 | ((node = hstate_next_node_to_free(hs, mask)) || 1); \ |
| 1473 | nr_nodes--) |
| 1474 | |
| 1475 | /* used to demote non-gigantic_huge pages as well */ |
| 1476 | static void __destroy_compound_gigantic_folio(struct folio *folio, |
| 1477 | unsigned int order, bool demote) |
| 1478 | { |
| 1479 | int i; |
| 1480 | int nr_pages = 1 << order; |
| 1481 | struct page *p; |
| 1482 | |
| 1483 | atomic_set(folio_mapcount_ptr(folio), 0); |
| 1484 | atomic_set(folio_subpages_mapcount_ptr(folio), 0); |
| 1485 | atomic_set(folio_pincount_ptr(folio), 0); |
| 1486 | |
| 1487 | for (i = 1; i < nr_pages; i++) { |
| 1488 | p = folio_page(folio, i); |
| 1489 | p->mapping = NULL; |
| 1490 | clear_compound_head(p); |
| 1491 | if (!demote) |
| 1492 | set_page_refcounted(p); |
| 1493 | } |
| 1494 | |
| 1495 | folio_set_compound_order(folio, 0); |
| 1496 | __folio_clear_head(folio); |
| 1497 | } |
| 1498 | |
| 1499 | static void destroy_compound_hugetlb_folio_for_demote(struct folio *folio, |
| 1500 | unsigned int order) |
| 1501 | { |
| 1502 | __destroy_compound_gigantic_folio(folio, order, true); |
| 1503 | } |
| 1504 | |
| 1505 | #ifdef CONFIG_ARCH_HAS_GIGANTIC_PAGE |
| 1506 | static void destroy_compound_gigantic_folio(struct folio *folio, |
| 1507 | unsigned int order) |
| 1508 | { |
| 1509 | __destroy_compound_gigantic_folio(folio, order, false); |
| 1510 | } |
| 1511 | |
| 1512 | static void free_gigantic_folio(struct folio *folio, unsigned int order) |
| 1513 | { |
| 1514 | /* |
| 1515 | * If the page isn't allocated using the cma allocator, |
| 1516 | * cma_release() returns false. |
| 1517 | */ |
| 1518 | #ifdef CONFIG_CMA |
| 1519 | int nid = folio_nid(folio); |
| 1520 | |
| 1521 | if (cma_release(hugetlb_cma[nid], &folio->page, 1 << order)) |
| 1522 | return; |
| 1523 | #endif |
| 1524 | |
| 1525 | free_contig_range(folio_pfn(folio), 1 << order); |
| 1526 | } |
| 1527 | |
| 1528 | #ifdef CONFIG_CONTIG_ALLOC |
| 1529 | static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask, |
| 1530 | int nid, nodemask_t *nodemask) |
| 1531 | { |
| 1532 | struct page *page; |
| 1533 | unsigned long nr_pages = pages_per_huge_page(h); |
| 1534 | if (nid == NUMA_NO_NODE) |
| 1535 | nid = numa_mem_id(); |
| 1536 | |
| 1537 | #ifdef CONFIG_CMA |
| 1538 | { |
| 1539 | int node; |
| 1540 | |
| 1541 | if (hugetlb_cma[nid]) { |
| 1542 | page = cma_alloc(hugetlb_cma[nid], nr_pages, |
| 1543 | huge_page_order(h), true); |
| 1544 | if (page) |
| 1545 | return page_folio(page); |
| 1546 | } |
| 1547 | |
| 1548 | if (!(gfp_mask & __GFP_THISNODE)) { |
| 1549 | for_each_node_mask(node, *nodemask) { |
| 1550 | if (node == nid || !hugetlb_cma[node]) |
| 1551 | continue; |
| 1552 | |
| 1553 | page = cma_alloc(hugetlb_cma[node], nr_pages, |
| 1554 | huge_page_order(h), true); |
| 1555 | if (page) |
| 1556 | return page_folio(page); |
| 1557 | } |
| 1558 | } |
| 1559 | } |
| 1560 | #endif |
| 1561 | |
| 1562 | page = alloc_contig_pages(nr_pages, gfp_mask, nid, nodemask); |
| 1563 | return page ? page_folio(page) : NULL; |
| 1564 | } |
| 1565 | |
| 1566 | #else /* !CONFIG_CONTIG_ALLOC */ |
| 1567 | static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask, |
| 1568 | int nid, nodemask_t *nodemask) |
| 1569 | { |
| 1570 | return NULL; |
| 1571 | } |
| 1572 | #endif /* CONFIG_CONTIG_ALLOC */ |
| 1573 | |
| 1574 | #else /* !CONFIG_ARCH_HAS_GIGANTIC_PAGE */ |
| 1575 | static struct folio *alloc_gigantic_folio(struct hstate *h, gfp_t gfp_mask, |
| 1576 | int nid, nodemask_t *nodemask) |
| 1577 | { |
| 1578 | return NULL; |
| 1579 | } |
| 1580 | static inline void free_gigantic_folio(struct folio *folio, |
| 1581 | unsigned int order) { } |
| 1582 | static inline void destroy_compound_gigantic_folio(struct folio *folio, |
| 1583 | unsigned int order) { } |
| 1584 | #endif |
| 1585 | |
| 1586 | /* |
| 1587 | * Remove hugetlb folio from lists, and update dtor so that the folio appears |
| 1588 | * as just a compound page. |
| 1589 | * |
| 1590 | * A reference is held on the folio, except in the case of demote. |
| 1591 | * |
| 1592 | * Must be called with hugetlb lock held. |
| 1593 | */ |
| 1594 | static void __remove_hugetlb_folio(struct hstate *h, struct folio *folio, |
| 1595 | bool adjust_surplus, |
| 1596 | bool demote) |
| 1597 | { |
| 1598 | int nid = folio_nid(folio); |
| 1599 | |
| 1600 | VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio(folio), folio); |
| 1601 | VM_BUG_ON_FOLIO(hugetlb_cgroup_from_folio_rsvd(folio), folio); |
| 1602 | |
| 1603 | lockdep_assert_held(&hugetlb_lock); |
| 1604 | if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| 1605 | return; |
| 1606 | |
| 1607 | list_del(&folio->lru); |
| 1608 | |
| 1609 | if (folio_test_hugetlb_freed(folio)) { |
| 1610 | h->free_huge_pages--; |
| 1611 | h->free_huge_pages_node[nid]--; |
| 1612 | } |
| 1613 | if (adjust_surplus) { |
| 1614 | h->surplus_huge_pages--; |
| 1615 | h->surplus_huge_pages_node[nid]--; |
| 1616 | } |
| 1617 | |
| 1618 | /* |
| 1619 | * Very subtle |
| 1620 | * |
| 1621 | * For non-gigantic pages set the destructor to the normal compound |
| 1622 | * page dtor. This is needed in case someone takes an additional |
| 1623 | * temporary ref to the page, and freeing is delayed until they drop |
| 1624 | * their reference. |
| 1625 | * |
| 1626 | * For gigantic pages set the destructor to the null dtor. This |
| 1627 | * destructor will never be called. Before freeing the gigantic |
| 1628 | * page destroy_compound_gigantic_folio will turn the folio into a |
| 1629 | * simple group of pages. After this the destructor does not |
| 1630 | * apply. |
| 1631 | * |
| 1632 | * This handles the case where more than one ref is held when and |
| 1633 | * after update_and_free_hugetlb_folio is called. |
| 1634 | * |
| 1635 | * In the case of demote we do not ref count the page as it will soon |
| 1636 | * be turned into a page of smaller size. |
| 1637 | */ |
| 1638 | if (!demote) |
| 1639 | folio_ref_unfreeze(folio, 1); |
| 1640 | if (hstate_is_gigantic(h)) |
| 1641 | folio_set_compound_dtor(folio, NULL_COMPOUND_DTOR); |
| 1642 | else |
| 1643 | folio_set_compound_dtor(folio, COMPOUND_PAGE_DTOR); |
| 1644 | |
| 1645 | h->nr_huge_pages--; |
| 1646 | h->nr_huge_pages_node[nid]--; |
| 1647 | } |
| 1648 | |
| 1649 | static void remove_hugetlb_folio(struct hstate *h, struct folio *folio, |
| 1650 | bool adjust_surplus) |
| 1651 | { |
| 1652 | __remove_hugetlb_folio(h, folio, adjust_surplus, false); |
| 1653 | } |
| 1654 | |
| 1655 | static void remove_hugetlb_folio_for_demote(struct hstate *h, struct folio *folio, |
| 1656 | bool adjust_surplus) |
| 1657 | { |
| 1658 | __remove_hugetlb_folio(h, folio, adjust_surplus, true); |
| 1659 | } |
| 1660 | |
| 1661 | static void add_hugetlb_folio(struct hstate *h, struct folio *folio, |
| 1662 | bool adjust_surplus) |
| 1663 | { |
| 1664 | int zeroed; |
| 1665 | int nid = folio_nid(folio); |
| 1666 | |
| 1667 | VM_BUG_ON_FOLIO(!folio_test_hugetlb_vmemmap_optimized(folio), folio); |
| 1668 | |
| 1669 | lockdep_assert_held(&hugetlb_lock); |
| 1670 | |
| 1671 | INIT_LIST_HEAD(&folio->lru); |
| 1672 | h->nr_huge_pages++; |
| 1673 | h->nr_huge_pages_node[nid]++; |
| 1674 | |
| 1675 | if (adjust_surplus) { |
| 1676 | h->surplus_huge_pages++; |
| 1677 | h->surplus_huge_pages_node[nid]++; |
| 1678 | } |
| 1679 | |
| 1680 | folio_set_compound_dtor(folio, HUGETLB_PAGE_DTOR); |
| 1681 | folio_change_private(folio, NULL); |
| 1682 | /* |
| 1683 | * We have to set hugetlb_vmemmap_optimized again as above |
| 1684 | * folio_change_private(folio, NULL) cleared it. |
| 1685 | */ |
| 1686 | folio_set_hugetlb_vmemmap_optimized(folio); |
| 1687 | |
| 1688 | /* |
| 1689 | * This folio is about to be managed by the hugetlb allocator and |
| 1690 | * should have no users. Drop our reference, and check for others |
| 1691 | * just in case. |
| 1692 | */ |
| 1693 | zeroed = folio_put_testzero(folio); |
| 1694 | if (unlikely(!zeroed)) |
| 1695 | /* |
| 1696 | * It is VERY unlikely soneone else has taken a ref on |
| 1697 | * the page. In this case, we simply return as the |
| 1698 | * hugetlb destructor (free_huge_page) will be called |
| 1699 | * when this other ref is dropped. |
| 1700 | */ |
| 1701 | return; |
| 1702 | |
| 1703 | arch_clear_hugepage_flags(&folio->page); |
| 1704 | enqueue_hugetlb_folio(h, folio); |
| 1705 | } |
| 1706 | |
| 1707 | static void __update_and_free_page(struct hstate *h, struct page *page) |
| 1708 | { |
| 1709 | int i; |
| 1710 | struct folio *folio = page_folio(page); |
| 1711 | struct page *subpage; |
| 1712 | |
| 1713 | if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| 1714 | return; |
| 1715 | |
| 1716 | /* |
| 1717 | * If we don't know which subpages are hwpoisoned, we can't free |
| 1718 | * the hugepage, so it's leaked intentionally. |
| 1719 | */ |
| 1720 | if (folio_test_hugetlb_raw_hwp_unreliable(folio)) |
| 1721 | return; |
| 1722 | |
| 1723 | if (hugetlb_vmemmap_restore(h, page)) { |
| 1724 | spin_lock_irq(&hugetlb_lock); |
| 1725 | /* |
| 1726 | * If we cannot allocate vmemmap pages, just refuse to free the |
| 1727 | * page and put the page back on the hugetlb free list and treat |
| 1728 | * as a surplus page. |
| 1729 | */ |
| 1730 | add_hugetlb_folio(h, folio, true); |
| 1731 | spin_unlock_irq(&hugetlb_lock); |
| 1732 | return; |
| 1733 | } |
| 1734 | |
| 1735 | /* |
| 1736 | * Move PageHWPoison flag from head page to the raw error pages, |
| 1737 | * which makes any healthy subpages reusable. |
| 1738 | */ |
| 1739 | if (unlikely(folio_test_hwpoison(folio))) |
| 1740 | hugetlb_clear_page_hwpoison(&folio->page); |
| 1741 | |
| 1742 | for (i = 0; i < pages_per_huge_page(h); i++) { |
| 1743 | subpage = folio_page(folio, i); |
| 1744 | subpage->flags &= ~(1 << PG_locked | 1 << PG_error | |
| 1745 | 1 << PG_referenced | 1 << PG_dirty | |
| 1746 | 1 << PG_active | 1 << PG_private | |
| 1747 | 1 << PG_writeback); |
| 1748 | } |
| 1749 | |
| 1750 | /* |
| 1751 | * Non-gigantic pages demoted from CMA allocated gigantic pages |
| 1752 | * need to be given back to CMA in free_gigantic_folio. |
| 1753 | */ |
| 1754 | if (hstate_is_gigantic(h) || |
| 1755 | hugetlb_cma_folio(folio, huge_page_order(h))) { |
| 1756 | destroy_compound_gigantic_folio(folio, huge_page_order(h)); |
| 1757 | free_gigantic_folio(folio, huge_page_order(h)); |
| 1758 | } else { |
| 1759 | __free_pages(page, huge_page_order(h)); |
| 1760 | } |
| 1761 | } |
| 1762 | |
| 1763 | /* |
| 1764 | * As update_and_free_hugetlb_folio() can be called under any context, so we cannot |
| 1765 | * use GFP_KERNEL to allocate vmemmap pages. However, we can defer the |
| 1766 | * actual freeing in a workqueue to prevent from using GFP_ATOMIC to allocate |
| 1767 | * the vmemmap pages. |
| 1768 | * |
| 1769 | * free_hpage_workfn() locklessly retrieves the linked list of pages to be |
| 1770 | * freed and frees them one-by-one. As the page->mapping pointer is going |
| 1771 | * to be cleared in free_hpage_workfn() anyway, it is reused as the llist_node |
| 1772 | * structure of a lockless linked list of huge pages to be freed. |
| 1773 | */ |
| 1774 | static LLIST_HEAD(hpage_freelist); |
| 1775 | |
| 1776 | static void free_hpage_workfn(struct work_struct *work) |
| 1777 | { |
| 1778 | struct llist_node *node; |
| 1779 | |
| 1780 | node = llist_del_all(&hpage_freelist); |
| 1781 | |
| 1782 | while (node) { |
| 1783 | struct page *page; |
| 1784 | struct hstate *h; |
| 1785 | |
| 1786 | page = container_of((struct address_space **)node, |
| 1787 | struct page, mapping); |
| 1788 | node = node->next; |
| 1789 | page->mapping = NULL; |
| 1790 | /* |
| 1791 | * The VM_BUG_ON_PAGE(!PageHuge(page), page) in page_hstate() |
| 1792 | * is going to trigger because a previous call to |
| 1793 | * remove_hugetlb_folio() will call folio_set_compound_dtor |
| 1794 | * (folio, NULL_COMPOUND_DTOR), so do not use page_hstate() |
| 1795 | * directly. |
| 1796 | */ |
| 1797 | h = size_to_hstate(page_size(page)); |
| 1798 | |
| 1799 | __update_and_free_page(h, page); |
| 1800 | |
| 1801 | cond_resched(); |
| 1802 | } |
| 1803 | } |
| 1804 | static DECLARE_WORK(free_hpage_work, free_hpage_workfn); |
| 1805 | |
| 1806 | static inline void flush_free_hpage_work(struct hstate *h) |
| 1807 | { |
| 1808 | if (hugetlb_vmemmap_optimizable(h)) |
| 1809 | flush_work(&free_hpage_work); |
| 1810 | } |
| 1811 | |
| 1812 | static void update_and_free_hugetlb_folio(struct hstate *h, struct folio *folio, |
| 1813 | bool atomic) |
| 1814 | { |
| 1815 | if (!folio_test_hugetlb_vmemmap_optimized(folio) || !atomic) { |
| 1816 | __update_and_free_page(h, &folio->page); |
| 1817 | return; |
| 1818 | } |
| 1819 | |
| 1820 | /* |
| 1821 | * Defer freeing to avoid using GFP_ATOMIC to allocate vmemmap pages. |
| 1822 | * |
| 1823 | * Only call schedule_work() if hpage_freelist is previously |
| 1824 | * empty. Otherwise, schedule_work() had been called but the workfn |
| 1825 | * hasn't retrieved the list yet. |
| 1826 | */ |
| 1827 | if (llist_add((struct llist_node *)&folio->mapping, &hpage_freelist)) |
| 1828 | schedule_work(&free_hpage_work); |
| 1829 | } |
| 1830 | |
| 1831 | static void update_and_free_pages_bulk(struct hstate *h, struct list_head *list) |
| 1832 | { |
| 1833 | struct page *page, *t_page; |
| 1834 | struct folio *folio; |
| 1835 | |
| 1836 | list_for_each_entry_safe(page, t_page, list, lru) { |
| 1837 | folio = page_folio(page); |
| 1838 | update_and_free_hugetlb_folio(h, folio, false); |
| 1839 | cond_resched(); |
| 1840 | } |
| 1841 | } |
| 1842 | |
| 1843 | struct hstate *size_to_hstate(unsigned long size) |
| 1844 | { |
| 1845 | struct hstate *h; |
| 1846 | |
| 1847 | for_each_hstate(h) { |
| 1848 | if (huge_page_size(h) == size) |
| 1849 | return h; |
| 1850 | } |
| 1851 | return NULL; |
| 1852 | } |
| 1853 | |
| 1854 | void free_huge_page(struct page *page) |
| 1855 | { |
| 1856 | /* |
| 1857 | * Can't pass hstate in here because it is called from the |
| 1858 | * compound page destructor. |
| 1859 | */ |
| 1860 | struct folio *folio = page_folio(page); |
| 1861 | struct hstate *h = folio_hstate(folio); |
| 1862 | int nid = folio_nid(folio); |
| 1863 | struct hugepage_subpool *spool = hugetlb_folio_subpool(folio); |
| 1864 | bool restore_reserve; |
| 1865 | unsigned long flags; |
| 1866 | |
| 1867 | VM_BUG_ON_FOLIO(folio_ref_count(folio), folio); |
| 1868 | VM_BUG_ON_FOLIO(folio_mapcount(folio), folio); |
| 1869 | |
| 1870 | hugetlb_set_folio_subpool(folio, NULL); |
| 1871 | if (folio_test_anon(folio)) |
| 1872 | __ClearPageAnonExclusive(&folio->page); |
| 1873 | folio->mapping = NULL; |
| 1874 | restore_reserve = folio_test_hugetlb_restore_reserve(folio); |
| 1875 | folio_clear_hugetlb_restore_reserve(folio); |
| 1876 | |
| 1877 | /* |
| 1878 | * If HPageRestoreReserve was set on page, page allocation consumed a |
| 1879 | * reservation. If the page was associated with a subpool, there |
| 1880 | * would have been a page reserved in the subpool before allocation |
| 1881 | * via hugepage_subpool_get_pages(). Since we are 'restoring' the |
| 1882 | * reservation, do not call hugepage_subpool_put_pages() as this will |
| 1883 | * remove the reserved page from the subpool. |
| 1884 | */ |
| 1885 | if (!restore_reserve) { |
| 1886 | /* |
| 1887 | * A return code of zero implies that the subpool will be |
| 1888 | * under its minimum size if the reservation is not restored |
| 1889 | * after page is free. Therefore, force restore_reserve |
| 1890 | * operation. |
| 1891 | */ |
| 1892 | if (hugepage_subpool_put_pages(spool, 1) == 0) |
| 1893 | restore_reserve = true; |
| 1894 | } |
| 1895 | |
| 1896 | spin_lock_irqsave(&hugetlb_lock, flags); |
| 1897 | folio_clear_hugetlb_migratable(folio); |
| 1898 | hugetlb_cgroup_uncharge_folio(hstate_index(h), |
| 1899 | pages_per_huge_page(h), folio); |
| 1900 | hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h), |
| 1901 | pages_per_huge_page(h), folio); |
| 1902 | if (restore_reserve) |
| 1903 | h->resv_huge_pages++; |
| 1904 | |
| 1905 | if (folio_test_hugetlb_temporary(folio)) { |
| 1906 | remove_hugetlb_folio(h, folio, false); |
| 1907 | spin_unlock_irqrestore(&hugetlb_lock, flags); |
| 1908 | update_and_free_hugetlb_folio(h, folio, true); |
| 1909 | } else if (h->surplus_huge_pages_node[nid]) { |
| 1910 | /* remove the page from active list */ |
| 1911 | remove_hugetlb_folio(h, folio, true); |
| 1912 | spin_unlock_irqrestore(&hugetlb_lock, flags); |
| 1913 | update_and_free_hugetlb_folio(h, folio, true); |
| 1914 | } else { |
| 1915 | arch_clear_hugepage_flags(page); |
| 1916 | enqueue_hugetlb_folio(h, folio); |
| 1917 | spin_unlock_irqrestore(&hugetlb_lock, flags); |
| 1918 | } |
| 1919 | } |
| 1920 | |
| 1921 | /* |
| 1922 | * Must be called with the hugetlb lock held |
| 1923 | */ |
| 1924 | static void __prep_account_new_huge_page(struct hstate *h, int nid) |
| 1925 | { |
| 1926 | lockdep_assert_held(&hugetlb_lock); |
| 1927 | h->nr_huge_pages++; |
| 1928 | h->nr_huge_pages_node[nid]++; |
| 1929 | } |
| 1930 | |
| 1931 | static void __prep_new_hugetlb_folio(struct hstate *h, struct folio *folio) |
| 1932 | { |
| 1933 | hugetlb_vmemmap_optimize(h, &folio->page); |
| 1934 | INIT_LIST_HEAD(&folio->lru); |
| 1935 | folio_set_compound_dtor(folio, HUGETLB_PAGE_DTOR); |
| 1936 | hugetlb_set_folio_subpool(folio, NULL); |
| 1937 | set_hugetlb_cgroup(folio, NULL); |
| 1938 | set_hugetlb_cgroup_rsvd(folio, NULL); |
| 1939 | } |
| 1940 | |
| 1941 | static void prep_new_hugetlb_folio(struct hstate *h, struct folio *folio, int nid) |
| 1942 | { |
| 1943 | __prep_new_hugetlb_folio(h, folio); |
| 1944 | spin_lock_irq(&hugetlb_lock); |
| 1945 | __prep_account_new_huge_page(h, nid); |
| 1946 | spin_unlock_irq(&hugetlb_lock); |
| 1947 | } |
| 1948 | |
| 1949 | static bool __prep_compound_gigantic_folio(struct folio *folio, |
| 1950 | unsigned int order, bool demote) |
| 1951 | { |
| 1952 | int i, j; |
| 1953 | int nr_pages = 1 << order; |
| 1954 | struct page *p; |
| 1955 | |
| 1956 | __folio_clear_reserved(folio); |
| 1957 | __folio_set_head(folio); |
| 1958 | /* we rely on prep_new_hugetlb_folio to set the destructor */ |
| 1959 | folio_set_compound_order(folio, order); |
| 1960 | for (i = 0; i < nr_pages; i++) { |
| 1961 | p = folio_page(folio, i); |
| 1962 | |
| 1963 | /* |
| 1964 | * For gigantic hugepages allocated through bootmem at |
| 1965 | * boot, it's safer to be consistent with the not-gigantic |
| 1966 | * hugepages and clear the PG_reserved bit from all tail pages |
| 1967 | * too. Otherwise drivers using get_user_pages() to access tail |
| 1968 | * pages may get the reference counting wrong if they see |
| 1969 | * PG_reserved set on a tail page (despite the head page not |
| 1970 | * having PG_reserved set). Enforcing this consistency between |
| 1971 | * head and tail pages allows drivers to optimize away a check |
| 1972 | * on the head page when they need know if put_page() is needed |
| 1973 | * after get_user_pages(). |
| 1974 | */ |
| 1975 | if (i != 0) /* head page cleared above */ |
| 1976 | __ClearPageReserved(p); |
| 1977 | /* |
| 1978 | * Subtle and very unlikely |
| 1979 | * |
| 1980 | * Gigantic 'page allocators' such as memblock or cma will |
| 1981 | * return a set of pages with each page ref counted. We need |
| 1982 | * to turn this set of pages into a compound page with tail |
| 1983 | * page ref counts set to zero. Code such as speculative page |
| 1984 | * cache adding could take a ref on a 'to be' tail page. |
| 1985 | * We need to respect any increased ref count, and only set |
| 1986 | * the ref count to zero if count is currently 1. If count |
| 1987 | * is not 1, we return an error. An error return indicates |
| 1988 | * the set of pages can not be converted to a gigantic page. |
| 1989 | * The caller who allocated the pages should then discard the |
| 1990 | * pages using the appropriate free interface. |
| 1991 | * |
| 1992 | * In the case of demote, the ref count will be zero. |
| 1993 | */ |
| 1994 | if (!demote) { |
| 1995 | if (!page_ref_freeze(p, 1)) { |
| 1996 | pr_warn("HugeTLB page can not be used due to unexpected inflated ref count\n"); |
| 1997 | goto out_error; |
| 1998 | } |
| 1999 | } else { |
| 2000 | VM_BUG_ON_PAGE(page_count(p), p); |
| 2001 | } |
| 2002 | if (i != 0) |
| 2003 | set_compound_head(p, &folio->page); |
| 2004 | } |
| 2005 | atomic_set(folio_mapcount_ptr(folio), -1); |
| 2006 | atomic_set(folio_subpages_mapcount_ptr(folio), 0); |
| 2007 | atomic_set(folio_pincount_ptr(folio), 0); |
| 2008 | return true; |
| 2009 | |
| 2010 | out_error: |
| 2011 | /* undo page modifications made above */ |
| 2012 | for (j = 0; j < i; j++) { |
| 2013 | p = folio_page(folio, j); |
| 2014 | if (j != 0) |
| 2015 | clear_compound_head(p); |
| 2016 | set_page_refcounted(p); |
| 2017 | } |
| 2018 | /* need to clear PG_reserved on remaining tail pages */ |
| 2019 | for (; j < nr_pages; j++) { |
| 2020 | p = folio_page(folio, j); |
| 2021 | __ClearPageReserved(p); |
| 2022 | } |
| 2023 | folio_set_compound_order(folio, 0); |
| 2024 | __folio_clear_head(folio); |
| 2025 | return false; |
| 2026 | } |
| 2027 | |
| 2028 | static bool prep_compound_gigantic_folio(struct folio *folio, |
| 2029 | unsigned int order) |
| 2030 | { |
| 2031 | return __prep_compound_gigantic_folio(folio, order, false); |
| 2032 | } |
| 2033 | |
| 2034 | static bool prep_compound_gigantic_folio_for_demote(struct folio *folio, |
| 2035 | unsigned int order) |
| 2036 | { |
| 2037 | return __prep_compound_gigantic_folio(folio, order, true); |
| 2038 | } |
| 2039 | |
| 2040 | /* |
| 2041 | * PageHuge() only returns true for hugetlbfs pages, but not for normal or |
| 2042 | * transparent huge pages. See the PageTransHuge() documentation for more |
| 2043 | * details. |
| 2044 | */ |
| 2045 | int PageHuge(struct page *page) |
| 2046 | { |
| 2047 | if (!PageCompound(page)) |
| 2048 | return 0; |
| 2049 | |
| 2050 | page = compound_head(page); |
| 2051 | return page[1].compound_dtor == HUGETLB_PAGE_DTOR; |
| 2052 | } |
| 2053 | EXPORT_SYMBOL_GPL(PageHuge); |
| 2054 | |
| 2055 | /* |
| 2056 | * PageHeadHuge() only returns true for hugetlbfs head page, but not for |
| 2057 | * normal or transparent huge pages. |
| 2058 | */ |
| 2059 | int PageHeadHuge(struct page *page_head) |
| 2060 | { |
| 2061 | if (!PageHead(page_head)) |
| 2062 | return 0; |
| 2063 | |
| 2064 | return page_head[1].compound_dtor == HUGETLB_PAGE_DTOR; |
| 2065 | } |
| 2066 | EXPORT_SYMBOL_GPL(PageHeadHuge); |
| 2067 | |
| 2068 | /* |
| 2069 | * Find and lock address space (mapping) in write mode. |
| 2070 | * |
| 2071 | * Upon entry, the page is locked which means that page_mapping() is |
| 2072 | * stable. Due to locking order, we can only trylock_write. If we can |
| 2073 | * not get the lock, simply return NULL to caller. |
| 2074 | */ |
| 2075 | struct address_space *hugetlb_page_mapping_lock_write(struct page *hpage) |
| 2076 | { |
| 2077 | struct address_space *mapping = page_mapping(hpage); |
| 2078 | |
| 2079 | if (!mapping) |
| 2080 | return mapping; |
| 2081 | |
| 2082 | if (i_mmap_trylock_write(mapping)) |
| 2083 | return mapping; |
| 2084 | |
| 2085 | return NULL; |
| 2086 | } |
| 2087 | |
| 2088 | pgoff_t hugetlb_basepage_index(struct page *page) |
| 2089 | { |
| 2090 | struct page *page_head = compound_head(page); |
| 2091 | pgoff_t index = page_index(page_head); |
| 2092 | unsigned long compound_idx; |
| 2093 | |
| 2094 | if (compound_order(page_head) >= MAX_ORDER) |
| 2095 | compound_idx = page_to_pfn(page) - page_to_pfn(page_head); |
| 2096 | else |
| 2097 | compound_idx = page - page_head; |
| 2098 | |
| 2099 | return (index << compound_order(page_head)) + compound_idx; |
| 2100 | } |
| 2101 | |
| 2102 | static struct folio *alloc_buddy_hugetlb_folio(struct hstate *h, |
| 2103 | gfp_t gfp_mask, int nid, nodemask_t *nmask, |
| 2104 | nodemask_t *node_alloc_noretry) |
| 2105 | { |
| 2106 | int order = huge_page_order(h); |
| 2107 | struct page *page; |
| 2108 | bool alloc_try_hard = true; |
| 2109 | bool retry = true; |
| 2110 | |
| 2111 | /* |
| 2112 | * By default we always try hard to allocate the page with |
| 2113 | * __GFP_RETRY_MAYFAIL flag. However, if we are allocating pages in |
| 2114 | * a loop (to adjust global huge page counts) and previous allocation |
| 2115 | * failed, do not continue to try hard on the same node. Use the |
| 2116 | * node_alloc_noretry bitmap to manage this state information. |
| 2117 | */ |
| 2118 | if (node_alloc_noretry && node_isset(nid, *node_alloc_noretry)) |
| 2119 | alloc_try_hard = false; |
| 2120 | gfp_mask |= __GFP_COMP|__GFP_NOWARN; |
| 2121 | if (alloc_try_hard) |
| 2122 | gfp_mask |= __GFP_RETRY_MAYFAIL; |
| 2123 | if (nid == NUMA_NO_NODE) |
| 2124 | nid = numa_mem_id(); |
| 2125 | retry: |
| 2126 | page = __alloc_pages(gfp_mask, order, nid, nmask); |
| 2127 | |
| 2128 | /* Freeze head page */ |
| 2129 | if (page && !page_ref_freeze(page, 1)) { |
| 2130 | __free_pages(page, order); |
| 2131 | if (retry) { /* retry once */ |
| 2132 | retry = false; |
| 2133 | goto retry; |
| 2134 | } |
| 2135 | /* WOW! twice in a row. */ |
| 2136 | pr_warn("HugeTLB head page unexpected inflated ref count\n"); |
| 2137 | page = NULL; |
| 2138 | } |
| 2139 | |
| 2140 | /* |
| 2141 | * If we did not specify __GFP_RETRY_MAYFAIL, but still got a page this |
| 2142 | * indicates an overall state change. Clear bit so that we resume |
| 2143 | * normal 'try hard' allocations. |
| 2144 | */ |
| 2145 | if (node_alloc_noretry && page && !alloc_try_hard) |
| 2146 | node_clear(nid, *node_alloc_noretry); |
| 2147 | |
| 2148 | /* |
| 2149 | * If we tried hard to get a page but failed, set bit so that |
| 2150 | * subsequent attempts will not try as hard until there is an |
| 2151 | * overall state change. |
| 2152 | */ |
| 2153 | if (node_alloc_noretry && !page && alloc_try_hard) |
| 2154 | node_set(nid, *node_alloc_noretry); |
| 2155 | |
| 2156 | if (!page) { |
| 2157 | __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| 2158 | return NULL; |
| 2159 | } |
| 2160 | |
| 2161 | __count_vm_event(HTLB_BUDDY_PGALLOC); |
| 2162 | return page_folio(page); |
| 2163 | } |
| 2164 | |
| 2165 | /* |
| 2166 | * Common helper to allocate a fresh hugetlb page. All specific allocators |
| 2167 | * should use this function to get new hugetlb pages |
| 2168 | * |
| 2169 | * Note that returned page is 'frozen': ref count of head page and all tail |
| 2170 | * pages is zero. |
| 2171 | */ |
| 2172 | static struct folio *alloc_fresh_hugetlb_folio(struct hstate *h, |
| 2173 | gfp_t gfp_mask, int nid, nodemask_t *nmask, |
| 2174 | nodemask_t *node_alloc_noretry) |
| 2175 | { |
| 2176 | struct folio *folio; |
| 2177 | bool retry = false; |
| 2178 | |
| 2179 | retry: |
| 2180 | if (hstate_is_gigantic(h)) |
| 2181 | folio = alloc_gigantic_folio(h, gfp_mask, nid, nmask); |
| 2182 | else |
| 2183 | folio = alloc_buddy_hugetlb_folio(h, gfp_mask, |
| 2184 | nid, nmask, node_alloc_noretry); |
| 2185 | if (!folio) |
| 2186 | return NULL; |
| 2187 | if (hstate_is_gigantic(h)) { |
| 2188 | if (!prep_compound_gigantic_folio(folio, huge_page_order(h))) { |
| 2189 | /* |
| 2190 | * Rare failure to convert pages to compound page. |
| 2191 | * Free pages and try again - ONCE! |
| 2192 | */ |
| 2193 | free_gigantic_folio(folio, huge_page_order(h)); |
| 2194 | if (!retry) { |
| 2195 | retry = true; |
| 2196 | goto retry; |
| 2197 | } |
| 2198 | return NULL; |
| 2199 | } |
| 2200 | } |
| 2201 | prep_new_hugetlb_folio(h, folio, folio_nid(folio)); |
| 2202 | |
| 2203 | return folio; |
| 2204 | } |
| 2205 | |
| 2206 | /* |
| 2207 | * Allocates a fresh page to the hugetlb allocator pool in the node interleaved |
| 2208 | * manner. |
| 2209 | */ |
| 2210 | static int alloc_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed, |
| 2211 | nodemask_t *node_alloc_noretry) |
| 2212 | { |
| 2213 | struct folio *folio; |
| 2214 | int nr_nodes, node; |
| 2215 | gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
| 2216 | |
| 2217 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
| 2218 | folio = alloc_fresh_hugetlb_folio(h, gfp_mask, node, |
| 2219 | nodes_allowed, node_alloc_noretry); |
| 2220 | if (folio) { |
| 2221 | free_huge_page(&folio->page); /* free it into the hugepage allocator */ |
| 2222 | return 1; |
| 2223 | } |
| 2224 | } |
| 2225 | |
| 2226 | return 0; |
| 2227 | } |
| 2228 | |
| 2229 | /* |
| 2230 | * Remove huge page from pool from next node to free. Attempt to keep |
| 2231 | * persistent huge pages more or less balanced over allowed nodes. |
| 2232 | * This routine only 'removes' the hugetlb page. The caller must make |
| 2233 | * an additional call to free the page to low level allocators. |
| 2234 | * Called with hugetlb_lock locked. |
| 2235 | */ |
| 2236 | static struct page *remove_pool_huge_page(struct hstate *h, |
| 2237 | nodemask_t *nodes_allowed, |
| 2238 | bool acct_surplus) |
| 2239 | { |
| 2240 | int nr_nodes, node; |
| 2241 | struct page *page = NULL; |
| 2242 | struct folio *folio; |
| 2243 | |
| 2244 | lockdep_assert_held(&hugetlb_lock); |
| 2245 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
| 2246 | /* |
| 2247 | * If we're returning unused surplus pages, only examine |
| 2248 | * nodes with surplus pages. |
| 2249 | */ |
| 2250 | if ((!acct_surplus || h->surplus_huge_pages_node[node]) && |
| 2251 | !list_empty(&h->hugepage_freelists[node])) { |
| 2252 | page = list_entry(h->hugepage_freelists[node].next, |
| 2253 | struct page, lru); |
| 2254 | folio = page_folio(page); |
| 2255 | remove_hugetlb_folio(h, folio, acct_surplus); |
| 2256 | break; |
| 2257 | } |
| 2258 | } |
| 2259 | |
| 2260 | return page; |
| 2261 | } |
| 2262 | |
| 2263 | /* |
| 2264 | * Dissolve a given free hugepage into free buddy pages. This function does |
| 2265 | * nothing for in-use hugepages and non-hugepages. |
| 2266 | * This function returns values like below: |
| 2267 | * |
| 2268 | * -ENOMEM: failed to allocate vmemmap pages to free the freed hugepages |
| 2269 | * when the system is under memory pressure and the feature of |
| 2270 | * freeing unused vmemmap pages associated with each hugetlb page |
| 2271 | * is enabled. |
| 2272 | * -EBUSY: failed to dissolved free hugepages or the hugepage is in-use |
| 2273 | * (allocated or reserved.) |
| 2274 | * 0: successfully dissolved free hugepages or the page is not a |
| 2275 | * hugepage (considered as already dissolved) |
| 2276 | */ |
| 2277 | int dissolve_free_huge_page(struct page *page) |
| 2278 | { |
| 2279 | int rc = -EBUSY; |
| 2280 | struct folio *folio = page_folio(page); |
| 2281 | |
| 2282 | retry: |
| 2283 | /* Not to disrupt normal path by vainly holding hugetlb_lock */ |
| 2284 | if (!folio_test_hugetlb(folio)) |
| 2285 | return 0; |
| 2286 | |
| 2287 | spin_lock_irq(&hugetlb_lock); |
| 2288 | if (!folio_test_hugetlb(folio)) { |
| 2289 | rc = 0; |
| 2290 | goto out; |
| 2291 | } |
| 2292 | |
| 2293 | if (!folio_ref_count(folio)) { |
| 2294 | struct hstate *h = folio_hstate(folio); |
| 2295 | if (!available_huge_pages(h)) |
| 2296 | goto out; |
| 2297 | |
| 2298 | /* |
| 2299 | * We should make sure that the page is already on the free list |
| 2300 | * when it is dissolved. |
| 2301 | */ |
| 2302 | if (unlikely(!folio_test_hugetlb_freed(folio))) { |
| 2303 | spin_unlock_irq(&hugetlb_lock); |
| 2304 | cond_resched(); |
| 2305 | |
| 2306 | /* |
| 2307 | * Theoretically, we should return -EBUSY when we |
| 2308 | * encounter this race. In fact, we have a chance |
| 2309 | * to successfully dissolve the page if we do a |
| 2310 | * retry. Because the race window is quite small. |
| 2311 | * If we seize this opportunity, it is an optimization |
| 2312 | * for increasing the success rate of dissolving page. |
| 2313 | */ |
| 2314 | goto retry; |
| 2315 | } |
| 2316 | |
| 2317 | remove_hugetlb_folio(h, folio, false); |
| 2318 | h->max_huge_pages--; |
| 2319 | spin_unlock_irq(&hugetlb_lock); |
| 2320 | |
| 2321 | /* |
| 2322 | * Normally update_and_free_hugtlb_folio will allocate required vmemmmap |
| 2323 | * before freeing the page. update_and_free_hugtlb_folio will fail to |
| 2324 | * free the page if it can not allocate required vmemmap. We |
| 2325 | * need to adjust max_huge_pages if the page is not freed. |
| 2326 | * Attempt to allocate vmemmmap here so that we can take |
| 2327 | * appropriate action on failure. |
| 2328 | */ |
| 2329 | rc = hugetlb_vmemmap_restore(h, &folio->page); |
| 2330 | if (!rc) { |
| 2331 | update_and_free_hugetlb_folio(h, folio, false); |
| 2332 | } else { |
| 2333 | spin_lock_irq(&hugetlb_lock); |
| 2334 | add_hugetlb_folio(h, folio, false); |
| 2335 | h->max_huge_pages++; |
| 2336 | spin_unlock_irq(&hugetlb_lock); |
| 2337 | } |
| 2338 | |
| 2339 | return rc; |
| 2340 | } |
| 2341 | out: |
| 2342 | spin_unlock_irq(&hugetlb_lock); |
| 2343 | return rc; |
| 2344 | } |
| 2345 | |
| 2346 | /* |
| 2347 | * Dissolve free hugepages in a given pfn range. Used by memory hotplug to |
| 2348 | * make specified memory blocks removable from the system. |
| 2349 | * Note that this will dissolve a free gigantic hugepage completely, if any |
| 2350 | * part of it lies within the given range. |
| 2351 | * Also note that if dissolve_free_huge_page() returns with an error, all |
| 2352 | * free hugepages that were dissolved before that error are lost. |
| 2353 | */ |
| 2354 | int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn) |
| 2355 | { |
| 2356 | unsigned long pfn; |
| 2357 | struct page *page; |
| 2358 | int rc = 0; |
| 2359 | unsigned int order; |
| 2360 | struct hstate *h; |
| 2361 | |
| 2362 | if (!hugepages_supported()) |
| 2363 | return rc; |
| 2364 | |
| 2365 | order = huge_page_order(&default_hstate); |
| 2366 | for_each_hstate(h) |
| 2367 | order = min(order, huge_page_order(h)); |
| 2368 | |
| 2369 | for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << order) { |
| 2370 | page = pfn_to_page(pfn); |
| 2371 | rc = dissolve_free_huge_page(page); |
| 2372 | if (rc) |
| 2373 | break; |
| 2374 | } |
| 2375 | |
| 2376 | return rc; |
| 2377 | } |
| 2378 | |
| 2379 | /* |
| 2380 | * Allocates a fresh surplus page from the page allocator. |
| 2381 | */ |
| 2382 | static struct page *alloc_surplus_huge_page(struct hstate *h, gfp_t gfp_mask, |
| 2383 | int nid, nodemask_t *nmask) |
| 2384 | { |
| 2385 | struct folio *folio = NULL; |
| 2386 | |
| 2387 | if (hstate_is_gigantic(h)) |
| 2388 | return NULL; |
| 2389 | |
| 2390 | spin_lock_irq(&hugetlb_lock); |
| 2391 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) |
| 2392 | goto out_unlock; |
| 2393 | spin_unlock_irq(&hugetlb_lock); |
| 2394 | |
| 2395 | folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL); |
| 2396 | if (!folio) |
| 2397 | return NULL; |
| 2398 | |
| 2399 | spin_lock_irq(&hugetlb_lock); |
| 2400 | /* |
| 2401 | * We could have raced with the pool size change. |
| 2402 | * Double check that and simply deallocate the new page |
| 2403 | * if we would end up overcommiting the surpluses. Abuse |
| 2404 | * temporary page to workaround the nasty free_huge_page |
| 2405 | * codeflow |
| 2406 | */ |
| 2407 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
| 2408 | folio_set_hugetlb_temporary(folio); |
| 2409 | spin_unlock_irq(&hugetlb_lock); |
| 2410 | free_huge_page(&folio->page); |
| 2411 | return NULL; |
| 2412 | } |
| 2413 | |
| 2414 | h->surplus_huge_pages++; |
| 2415 | h->surplus_huge_pages_node[folio_nid(folio)]++; |
| 2416 | |
| 2417 | out_unlock: |
| 2418 | spin_unlock_irq(&hugetlb_lock); |
| 2419 | |
| 2420 | return &folio->page; |
| 2421 | } |
| 2422 | |
| 2423 | static struct page *alloc_migrate_huge_page(struct hstate *h, gfp_t gfp_mask, |
| 2424 | int nid, nodemask_t *nmask) |
| 2425 | { |
| 2426 | struct folio *folio; |
| 2427 | |
| 2428 | if (hstate_is_gigantic(h)) |
| 2429 | return NULL; |
| 2430 | |
| 2431 | folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL); |
| 2432 | if (!folio) |
| 2433 | return NULL; |
| 2434 | |
| 2435 | /* fresh huge pages are frozen */ |
| 2436 | folio_ref_unfreeze(folio, 1); |
| 2437 | /* |
| 2438 | * We do not account these pages as surplus because they are only |
| 2439 | * temporary and will be released properly on the last reference |
| 2440 | */ |
| 2441 | folio_set_hugetlb_temporary(folio); |
| 2442 | |
| 2443 | return &folio->page; |
| 2444 | } |
| 2445 | |
| 2446 | /* |
| 2447 | * Use the VMA's mpolicy to allocate a huge page from the buddy. |
| 2448 | */ |
| 2449 | static |
| 2450 | struct page *alloc_buddy_huge_page_with_mpol(struct hstate *h, |
| 2451 | struct vm_area_struct *vma, unsigned long addr) |
| 2452 | { |
| 2453 | struct page *page = NULL; |
| 2454 | struct mempolicy *mpol; |
| 2455 | gfp_t gfp_mask = htlb_alloc_mask(h); |
| 2456 | int nid; |
| 2457 | nodemask_t *nodemask; |
| 2458 | |
| 2459 | nid = huge_node(vma, addr, gfp_mask, &mpol, &nodemask); |
| 2460 | if (mpol_is_preferred_many(mpol)) { |
| 2461 | gfp_t gfp = gfp_mask | __GFP_NOWARN; |
| 2462 | |
| 2463 | gfp &= ~(__GFP_DIRECT_RECLAIM | __GFP_NOFAIL); |
| 2464 | page = alloc_surplus_huge_page(h, gfp, nid, nodemask); |
| 2465 | |
| 2466 | /* Fallback to all nodes if page==NULL */ |
| 2467 | nodemask = NULL; |
| 2468 | } |
| 2469 | |
| 2470 | if (!page) |
| 2471 | page = alloc_surplus_huge_page(h, gfp_mask, nid, nodemask); |
| 2472 | mpol_cond_put(mpol); |
| 2473 | return page; |
| 2474 | } |
| 2475 | |
| 2476 | /* page migration callback function */ |
| 2477 | struct page *alloc_huge_page_nodemask(struct hstate *h, int preferred_nid, |
| 2478 | nodemask_t *nmask, gfp_t gfp_mask) |
| 2479 | { |
| 2480 | spin_lock_irq(&hugetlb_lock); |
| 2481 | if (available_huge_pages(h)) { |
| 2482 | struct page *page; |
| 2483 | |
| 2484 | page = dequeue_huge_page_nodemask(h, gfp_mask, preferred_nid, nmask); |
| 2485 | if (page) { |
| 2486 | spin_unlock_irq(&hugetlb_lock); |
| 2487 | return page; |
| 2488 | } |
| 2489 | } |
| 2490 | spin_unlock_irq(&hugetlb_lock); |
| 2491 | |
| 2492 | return alloc_migrate_huge_page(h, gfp_mask, preferred_nid, nmask); |
| 2493 | } |
| 2494 | |
| 2495 | /* mempolicy aware migration callback */ |
| 2496 | struct page *alloc_huge_page_vma(struct hstate *h, struct vm_area_struct *vma, |
| 2497 | unsigned long address) |
| 2498 | { |
| 2499 | struct mempolicy *mpol; |
| 2500 | nodemask_t *nodemask; |
| 2501 | struct page *page; |
| 2502 | gfp_t gfp_mask; |
| 2503 | int node; |
| 2504 | |
| 2505 | gfp_mask = htlb_alloc_mask(h); |
| 2506 | node = huge_node(vma, address, gfp_mask, &mpol, &nodemask); |
| 2507 | page = alloc_huge_page_nodemask(h, node, nodemask, gfp_mask); |
| 2508 | mpol_cond_put(mpol); |
| 2509 | |
| 2510 | return page; |
| 2511 | } |
| 2512 | |
| 2513 | /* |
| 2514 | * Increase the hugetlb pool such that it can accommodate a reservation |
| 2515 | * of size 'delta'. |
| 2516 | */ |
| 2517 | static int gather_surplus_pages(struct hstate *h, long delta) |
| 2518 | __must_hold(&hugetlb_lock) |
| 2519 | { |
| 2520 | LIST_HEAD(surplus_list); |
| 2521 | struct page *page, *tmp; |
| 2522 | int ret; |
| 2523 | long i; |
| 2524 | long needed, allocated; |
| 2525 | bool alloc_ok = true; |
| 2526 | |
| 2527 | lockdep_assert_held(&hugetlb_lock); |
| 2528 | needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
| 2529 | if (needed <= 0) { |
| 2530 | h->resv_huge_pages += delta; |
| 2531 | return 0; |
| 2532 | } |
| 2533 | |
| 2534 | allocated = 0; |
| 2535 | |
| 2536 | ret = -ENOMEM; |
| 2537 | retry: |
| 2538 | spin_unlock_irq(&hugetlb_lock); |
| 2539 | for (i = 0; i < needed; i++) { |
| 2540 | page = alloc_surplus_huge_page(h, htlb_alloc_mask(h), |
| 2541 | NUMA_NO_NODE, NULL); |
| 2542 | if (!page) { |
| 2543 | alloc_ok = false; |
| 2544 | break; |
| 2545 | } |
| 2546 | list_add(&page->lru, &surplus_list); |
| 2547 | cond_resched(); |
| 2548 | } |
| 2549 | allocated += i; |
| 2550 | |
| 2551 | /* |
| 2552 | * After retaking hugetlb_lock, we need to recalculate 'needed' |
| 2553 | * because either resv_huge_pages or free_huge_pages may have changed. |
| 2554 | */ |
| 2555 | spin_lock_irq(&hugetlb_lock); |
| 2556 | needed = (h->resv_huge_pages + delta) - |
| 2557 | (h->free_huge_pages + allocated); |
| 2558 | if (needed > 0) { |
| 2559 | if (alloc_ok) |
| 2560 | goto retry; |
| 2561 | /* |
| 2562 | * We were not able to allocate enough pages to |
| 2563 | * satisfy the entire reservation so we free what |
| 2564 | * we've allocated so far. |
| 2565 | */ |
| 2566 | goto free; |
| 2567 | } |
| 2568 | /* |
| 2569 | * The surplus_list now contains _at_least_ the number of extra pages |
| 2570 | * needed to accommodate the reservation. Add the appropriate number |
| 2571 | * of pages to the hugetlb pool and free the extras back to the buddy |
| 2572 | * allocator. Commit the entire reservation here to prevent another |
| 2573 | * process from stealing the pages as they are added to the pool but |
| 2574 | * before they are reserved. |
| 2575 | */ |
| 2576 | needed += allocated; |
| 2577 | h->resv_huge_pages += delta; |
| 2578 | ret = 0; |
| 2579 | |
| 2580 | /* Free the needed pages to the hugetlb pool */ |
| 2581 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| 2582 | if ((--needed) < 0) |
| 2583 | break; |
| 2584 | /* Add the page to the hugetlb allocator */ |
| 2585 | enqueue_hugetlb_folio(h, page_folio(page)); |
| 2586 | } |
| 2587 | free: |
| 2588 | spin_unlock_irq(&hugetlb_lock); |
| 2589 | |
| 2590 | /* |
| 2591 | * Free unnecessary surplus pages to the buddy allocator. |
| 2592 | * Pages have no ref count, call free_huge_page directly. |
| 2593 | */ |
| 2594 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) |
| 2595 | free_huge_page(page); |
| 2596 | spin_lock_irq(&hugetlb_lock); |
| 2597 | |
| 2598 | return ret; |
| 2599 | } |
| 2600 | |
| 2601 | /* |
| 2602 | * This routine has two main purposes: |
| 2603 | * 1) Decrement the reservation count (resv_huge_pages) by the value passed |
| 2604 | * in unused_resv_pages. This corresponds to the prior adjustments made |
| 2605 | * to the associated reservation map. |
| 2606 | * 2) Free any unused surplus pages that may have been allocated to satisfy |
| 2607 | * the reservation. As many as unused_resv_pages may be freed. |
| 2608 | */ |
| 2609 | static void return_unused_surplus_pages(struct hstate *h, |
| 2610 | unsigned long unused_resv_pages) |
| 2611 | { |
| 2612 | unsigned long nr_pages; |
| 2613 | struct page *page; |
| 2614 | LIST_HEAD(page_list); |
| 2615 | |
| 2616 | lockdep_assert_held(&hugetlb_lock); |
| 2617 | /* Uncommit the reservation */ |
| 2618 | h->resv_huge_pages -= unused_resv_pages; |
| 2619 | |
| 2620 | if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| 2621 | goto out; |
| 2622 | |
| 2623 | /* |
| 2624 | * Part (or even all) of the reservation could have been backed |
| 2625 | * by pre-allocated pages. Only free surplus pages. |
| 2626 | */ |
| 2627 | nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
| 2628 | |
| 2629 | /* |
| 2630 | * We want to release as many surplus pages as possible, spread |
| 2631 | * evenly across all nodes with memory. Iterate across these nodes |
| 2632 | * until we can no longer free unreserved surplus pages. This occurs |
| 2633 | * when the nodes with surplus pages have no free pages. |
| 2634 | * remove_pool_huge_page() will balance the freed pages across the |
| 2635 | * on-line nodes with memory and will handle the hstate accounting. |
| 2636 | */ |
| 2637 | while (nr_pages--) { |
| 2638 | page = remove_pool_huge_page(h, &node_states[N_MEMORY], 1); |
| 2639 | if (!page) |
| 2640 | goto out; |
| 2641 | |
| 2642 | list_add(&page->lru, &page_list); |
| 2643 | } |
| 2644 | |
| 2645 | out: |
| 2646 | spin_unlock_irq(&hugetlb_lock); |
| 2647 | update_and_free_pages_bulk(h, &page_list); |
| 2648 | spin_lock_irq(&hugetlb_lock); |
| 2649 | } |
| 2650 | |
| 2651 | |
| 2652 | /* |
| 2653 | * vma_needs_reservation, vma_commit_reservation and vma_end_reservation |
| 2654 | * are used by the huge page allocation routines to manage reservations. |
| 2655 | * |
| 2656 | * vma_needs_reservation is called to determine if the huge page at addr |
| 2657 | * within the vma has an associated reservation. If a reservation is |
| 2658 | * needed, the value 1 is returned. The caller is then responsible for |
| 2659 | * managing the global reservation and subpool usage counts. After |
| 2660 | * the huge page has been allocated, vma_commit_reservation is called |
| 2661 | * to add the page to the reservation map. If the page allocation fails, |
| 2662 | * the reservation must be ended instead of committed. vma_end_reservation |
| 2663 | * is called in such cases. |
| 2664 | * |
| 2665 | * In the normal case, vma_commit_reservation returns the same value |
| 2666 | * as the preceding vma_needs_reservation call. The only time this |
| 2667 | * is not the case is if a reserve map was changed between calls. It |
| 2668 | * is the responsibility of the caller to notice the difference and |
| 2669 | * take appropriate action. |
| 2670 | * |
| 2671 | * vma_add_reservation is used in error paths where a reservation must |
| 2672 | * be restored when a newly allocated huge page must be freed. It is |
| 2673 | * to be called after calling vma_needs_reservation to determine if a |
| 2674 | * reservation exists. |
| 2675 | * |
| 2676 | * vma_del_reservation is used in error paths where an entry in the reserve |
| 2677 | * map was created during huge page allocation and must be removed. It is to |
| 2678 | * be called after calling vma_needs_reservation to determine if a reservation |
| 2679 | * exists. |
| 2680 | */ |
| 2681 | enum vma_resv_mode { |
| 2682 | VMA_NEEDS_RESV, |
| 2683 | VMA_COMMIT_RESV, |
| 2684 | VMA_END_RESV, |
| 2685 | VMA_ADD_RESV, |
| 2686 | VMA_DEL_RESV, |
| 2687 | }; |
| 2688 | static long __vma_reservation_common(struct hstate *h, |
| 2689 | struct vm_area_struct *vma, unsigned long addr, |
| 2690 | enum vma_resv_mode mode) |
| 2691 | { |
| 2692 | struct resv_map *resv; |
| 2693 | pgoff_t idx; |
| 2694 | long ret; |
| 2695 | long dummy_out_regions_needed; |
| 2696 | |
| 2697 | resv = vma_resv_map(vma); |
| 2698 | if (!resv) |
| 2699 | return 1; |
| 2700 | |
| 2701 | idx = vma_hugecache_offset(h, vma, addr); |
| 2702 | switch (mode) { |
| 2703 | case VMA_NEEDS_RESV: |
| 2704 | ret = region_chg(resv, idx, idx + 1, &dummy_out_regions_needed); |
| 2705 | /* We assume that vma_reservation_* routines always operate on |
| 2706 | * 1 page, and that adding to resv map a 1 page entry can only |
| 2707 | * ever require 1 region. |
| 2708 | */ |
| 2709 | VM_BUG_ON(dummy_out_regions_needed != 1); |
| 2710 | break; |
| 2711 | case VMA_COMMIT_RESV: |
| 2712 | ret = region_add(resv, idx, idx + 1, 1, NULL, NULL); |
| 2713 | /* region_add calls of range 1 should never fail. */ |
| 2714 | VM_BUG_ON(ret < 0); |
| 2715 | break; |
| 2716 | case VMA_END_RESV: |
| 2717 | region_abort(resv, idx, idx + 1, 1); |
| 2718 | ret = 0; |
| 2719 | break; |
| 2720 | case VMA_ADD_RESV: |
| 2721 | if (vma->vm_flags & VM_MAYSHARE) { |
| 2722 | ret = region_add(resv, idx, idx + 1, 1, NULL, NULL); |
| 2723 | /* region_add calls of range 1 should never fail. */ |
| 2724 | VM_BUG_ON(ret < 0); |
| 2725 | } else { |
| 2726 | region_abort(resv, idx, idx + 1, 1); |
| 2727 | ret = region_del(resv, idx, idx + 1); |
| 2728 | } |
| 2729 | break; |
| 2730 | case VMA_DEL_RESV: |
| 2731 | if (vma->vm_flags & VM_MAYSHARE) { |
| 2732 | region_abort(resv, idx, idx + 1, 1); |
| 2733 | ret = region_del(resv, idx, idx + 1); |
| 2734 | } else { |
| 2735 | ret = region_add(resv, idx, idx + 1, 1, NULL, NULL); |
| 2736 | /* region_add calls of range 1 should never fail. */ |
| 2737 | VM_BUG_ON(ret < 0); |
| 2738 | } |
| 2739 | break; |
| 2740 | default: |
| 2741 | BUG(); |
| 2742 | } |
| 2743 | |
| 2744 | if (vma->vm_flags & VM_MAYSHARE || mode == VMA_DEL_RESV) |
| 2745 | return ret; |
| 2746 | /* |
| 2747 | * We know private mapping must have HPAGE_RESV_OWNER set. |
| 2748 | * |
| 2749 | * In most cases, reserves always exist for private mappings. |
| 2750 | * However, a file associated with mapping could have been |
| 2751 | * hole punched or truncated after reserves were consumed. |
| 2752 | * As subsequent fault on such a range will not use reserves. |
| 2753 | * Subtle - The reserve map for private mappings has the |
| 2754 | * opposite meaning than that of shared mappings. If NO |
| 2755 | * entry is in the reserve map, it means a reservation exists. |
| 2756 | * If an entry exists in the reserve map, it means the |
| 2757 | * reservation has already been consumed. As a result, the |
| 2758 | * return value of this routine is the opposite of the |
| 2759 | * value returned from reserve map manipulation routines above. |
| 2760 | */ |
| 2761 | if (ret > 0) |
| 2762 | return 0; |
| 2763 | if (ret == 0) |
| 2764 | return 1; |
| 2765 | return ret; |
| 2766 | } |
| 2767 | |
| 2768 | static long vma_needs_reservation(struct hstate *h, |
| 2769 | struct vm_area_struct *vma, unsigned long addr) |
| 2770 | { |
| 2771 | return __vma_reservation_common(h, vma, addr, VMA_NEEDS_RESV); |
| 2772 | } |
| 2773 | |
| 2774 | static long vma_commit_reservation(struct hstate *h, |
| 2775 | struct vm_area_struct *vma, unsigned long addr) |
| 2776 | { |
| 2777 | return __vma_reservation_common(h, vma, addr, VMA_COMMIT_RESV); |
| 2778 | } |
| 2779 | |
| 2780 | static void vma_end_reservation(struct hstate *h, |
| 2781 | struct vm_area_struct *vma, unsigned long addr) |
| 2782 | { |
| 2783 | (void)__vma_reservation_common(h, vma, addr, VMA_END_RESV); |
| 2784 | } |
| 2785 | |
| 2786 | static long vma_add_reservation(struct hstate *h, |
| 2787 | struct vm_area_struct *vma, unsigned long addr) |
| 2788 | { |
| 2789 | return __vma_reservation_common(h, vma, addr, VMA_ADD_RESV); |
| 2790 | } |
| 2791 | |
| 2792 | static long vma_del_reservation(struct hstate *h, |
| 2793 | struct vm_area_struct *vma, unsigned long addr) |
| 2794 | { |
| 2795 | return __vma_reservation_common(h, vma, addr, VMA_DEL_RESV); |
| 2796 | } |
| 2797 | |
| 2798 | /* |
| 2799 | * This routine is called to restore reservation information on error paths. |
| 2800 | * It should ONLY be called for pages allocated via alloc_huge_page(), and |
| 2801 | * the hugetlb mutex should remain held when calling this routine. |
| 2802 | * |
| 2803 | * It handles two specific cases: |
| 2804 | * 1) A reservation was in place and the page consumed the reservation. |
| 2805 | * HPageRestoreReserve is set in the page. |
| 2806 | * 2) No reservation was in place for the page, so HPageRestoreReserve is |
| 2807 | * not set. However, alloc_huge_page always updates the reserve map. |
| 2808 | * |
| 2809 | * In case 1, free_huge_page later in the error path will increment the |
| 2810 | * global reserve count. But, free_huge_page does not have enough context |
| 2811 | * to adjust the reservation map. This case deals primarily with private |
| 2812 | * mappings. Adjust the reserve map here to be consistent with global |
| 2813 | * reserve count adjustments to be made by free_huge_page. Make sure the |
| 2814 | * reserve map indicates there is a reservation present. |
| 2815 | * |
| 2816 | * In case 2, simply undo reserve map modifications done by alloc_huge_page. |
| 2817 | */ |
| 2818 | void restore_reserve_on_error(struct hstate *h, struct vm_area_struct *vma, |
| 2819 | unsigned long address, struct page *page) |
| 2820 | { |
| 2821 | long rc = vma_needs_reservation(h, vma, address); |
| 2822 | |
| 2823 | if (HPageRestoreReserve(page)) { |
| 2824 | if (unlikely(rc < 0)) |
| 2825 | /* |
| 2826 | * Rare out of memory condition in reserve map |
| 2827 | * manipulation. Clear HPageRestoreReserve so that |
| 2828 | * global reserve count will not be incremented |
| 2829 | * by free_huge_page. This will make it appear |
| 2830 | * as though the reservation for this page was |
| 2831 | * consumed. This may prevent the task from |
| 2832 | * faulting in the page at a later time. This |
| 2833 | * is better than inconsistent global huge page |
| 2834 | * accounting of reserve counts. |
| 2835 | */ |
| 2836 | ClearHPageRestoreReserve(page); |
| 2837 | else if (rc) |
| 2838 | (void)vma_add_reservation(h, vma, address); |
| 2839 | else |
| 2840 | vma_end_reservation(h, vma, address); |
| 2841 | } else { |
| 2842 | if (!rc) { |
| 2843 | /* |
| 2844 | * This indicates there is an entry in the reserve map |
| 2845 | * not added by alloc_huge_page. We know it was added |
| 2846 | * before the alloc_huge_page call, otherwise |
| 2847 | * HPageRestoreReserve would be set on the page. |
| 2848 | * Remove the entry so that a subsequent allocation |
| 2849 | * does not consume a reservation. |
| 2850 | */ |
| 2851 | rc = vma_del_reservation(h, vma, address); |
| 2852 | if (rc < 0) |
| 2853 | /* |
| 2854 | * VERY rare out of memory condition. Since |
| 2855 | * we can not delete the entry, set |
| 2856 | * HPageRestoreReserve so that the reserve |
| 2857 | * count will be incremented when the page |
| 2858 | * is freed. This reserve will be consumed |
| 2859 | * on a subsequent allocation. |
| 2860 | */ |
| 2861 | SetHPageRestoreReserve(page); |
| 2862 | } else if (rc < 0) { |
| 2863 | /* |
| 2864 | * Rare out of memory condition from |
| 2865 | * vma_needs_reservation call. Memory allocation is |
| 2866 | * only attempted if a new entry is needed. Therefore, |
| 2867 | * this implies there is not an entry in the |
| 2868 | * reserve map. |
| 2869 | * |
| 2870 | * For shared mappings, no entry in the map indicates |
| 2871 | * no reservation. We are done. |
| 2872 | */ |
| 2873 | if (!(vma->vm_flags & VM_MAYSHARE)) |
| 2874 | /* |
| 2875 | * For private mappings, no entry indicates |
| 2876 | * a reservation is present. Since we can |
| 2877 | * not add an entry, set SetHPageRestoreReserve |
| 2878 | * on the page so reserve count will be |
| 2879 | * incremented when freed. This reserve will |
| 2880 | * be consumed on a subsequent allocation. |
| 2881 | */ |
| 2882 | SetHPageRestoreReserve(page); |
| 2883 | } else |
| 2884 | /* |
| 2885 | * No reservation present, do nothing |
| 2886 | */ |
| 2887 | vma_end_reservation(h, vma, address); |
| 2888 | } |
| 2889 | } |
| 2890 | |
| 2891 | /* |
| 2892 | * alloc_and_dissolve_hugetlb_folio - Allocate a new folio and dissolve |
| 2893 | * the old one |
| 2894 | * @h: struct hstate old page belongs to |
| 2895 | * @old_folio: Old folio to dissolve |
| 2896 | * @list: List to isolate the page in case we need to |
| 2897 | * Returns 0 on success, otherwise negated error. |
| 2898 | */ |
| 2899 | static int alloc_and_dissolve_hugetlb_folio(struct hstate *h, |
| 2900 | struct folio *old_folio, struct list_head *list) |
| 2901 | { |
| 2902 | gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
| 2903 | int nid = folio_nid(old_folio); |
| 2904 | struct folio *new_folio; |
| 2905 | int ret = 0; |
| 2906 | |
| 2907 | /* |
| 2908 | * Before dissolving the folio, we need to allocate a new one for the |
| 2909 | * pool to remain stable. Here, we allocate the folio and 'prep' it |
| 2910 | * by doing everything but actually updating counters and adding to |
| 2911 | * the pool. This simplifies and let us do most of the processing |
| 2912 | * under the lock. |
| 2913 | */ |
| 2914 | new_folio = alloc_buddy_hugetlb_folio(h, gfp_mask, nid, NULL, NULL); |
| 2915 | if (!new_folio) |
| 2916 | return -ENOMEM; |
| 2917 | __prep_new_hugetlb_folio(h, new_folio); |
| 2918 | |
| 2919 | retry: |
| 2920 | spin_lock_irq(&hugetlb_lock); |
| 2921 | if (!folio_test_hugetlb(old_folio)) { |
| 2922 | /* |
| 2923 | * Freed from under us. Drop new_folio too. |
| 2924 | */ |
| 2925 | goto free_new; |
| 2926 | } else if (folio_ref_count(old_folio)) { |
| 2927 | /* |
| 2928 | * Someone has grabbed the folio, try to isolate it here. |
| 2929 | * Fail with -EBUSY if not possible. |
| 2930 | */ |
| 2931 | spin_unlock_irq(&hugetlb_lock); |
| 2932 | ret = isolate_hugetlb(&old_folio->page, list); |
| 2933 | spin_lock_irq(&hugetlb_lock); |
| 2934 | goto free_new; |
| 2935 | } else if (!folio_test_hugetlb_freed(old_folio)) { |
| 2936 | /* |
| 2937 | * Folio's refcount is 0 but it has not been enqueued in the |
| 2938 | * freelist yet. Race window is small, so we can succeed here if |
| 2939 | * we retry. |
| 2940 | */ |
| 2941 | spin_unlock_irq(&hugetlb_lock); |
| 2942 | cond_resched(); |
| 2943 | goto retry; |
| 2944 | } else { |
| 2945 | /* |
| 2946 | * Ok, old_folio is still a genuine free hugepage. Remove it from |
| 2947 | * the freelist and decrease the counters. These will be |
| 2948 | * incremented again when calling __prep_account_new_huge_page() |
| 2949 | * and enqueue_hugetlb_folio() for new_folio. The counters will |
| 2950 | * remain stable since this happens under the lock. |
| 2951 | */ |
| 2952 | remove_hugetlb_folio(h, old_folio, false); |
| 2953 | |
| 2954 | /* |
| 2955 | * Ref count on new_folio is already zero as it was dropped |
| 2956 | * earlier. It can be directly added to the pool free list. |
| 2957 | */ |
| 2958 | __prep_account_new_huge_page(h, nid); |
| 2959 | enqueue_hugetlb_folio(h, new_folio); |
| 2960 | |
| 2961 | /* |
| 2962 | * Folio has been replaced, we can safely free the old one. |
| 2963 | */ |
| 2964 | spin_unlock_irq(&hugetlb_lock); |
| 2965 | update_and_free_hugetlb_folio(h, old_folio, false); |
| 2966 | } |
| 2967 | |
| 2968 | return ret; |
| 2969 | |
| 2970 | free_new: |
| 2971 | spin_unlock_irq(&hugetlb_lock); |
| 2972 | /* Folio has a zero ref count, but needs a ref to be freed */ |
| 2973 | folio_ref_unfreeze(new_folio, 1); |
| 2974 | update_and_free_hugetlb_folio(h, new_folio, false); |
| 2975 | |
| 2976 | return ret; |
| 2977 | } |
| 2978 | |
| 2979 | int isolate_or_dissolve_huge_page(struct page *page, struct list_head *list) |
| 2980 | { |
| 2981 | struct hstate *h; |
| 2982 | struct folio *folio = page_folio(page); |
| 2983 | int ret = -EBUSY; |
| 2984 | |
| 2985 | /* |
| 2986 | * The page might have been dissolved from under our feet, so make sure |
| 2987 | * to carefully check the state under the lock. |
| 2988 | * Return success when racing as if we dissolved the page ourselves. |
| 2989 | */ |
| 2990 | spin_lock_irq(&hugetlb_lock); |
| 2991 | if (folio_test_hugetlb(folio)) { |
| 2992 | h = folio_hstate(folio); |
| 2993 | } else { |
| 2994 | spin_unlock_irq(&hugetlb_lock); |
| 2995 | return 0; |
| 2996 | } |
| 2997 | spin_unlock_irq(&hugetlb_lock); |
| 2998 | |
| 2999 | /* |
| 3000 | * Fence off gigantic pages as there is a cyclic dependency between |
| 3001 | * alloc_contig_range and them. Return -ENOMEM as this has the effect |
| 3002 | * of bailing out right away without further retrying. |
| 3003 | */ |
| 3004 | if (hstate_is_gigantic(h)) |
| 3005 | return -ENOMEM; |
| 3006 | |
| 3007 | if (folio_ref_count(folio) && !isolate_hugetlb(&folio->page, list)) |
| 3008 | ret = 0; |
| 3009 | else if (!folio_ref_count(folio)) |
| 3010 | ret = alloc_and_dissolve_hugetlb_folio(h, folio, list); |
| 3011 | |
| 3012 | return ret; |
| 3013 | } |
| 3014 | |
| 3015 | struct page *alloc_huge_page(struct vm_area_struct *vma, |
| 3016 | unsigned long addr, int avoid_reserve) |
| 3017 | { |
| 3018 | struct hugepage_subpool *spool = subpool_vma(vma); |
| 3019 | struct hstate *h = hstate_vma(vma); |
| 3020 | struct page *page; |
| 3021 | struct folio *folio; |
| 3022 | long map_chg, map_commit; |
| 3023 | long gbl_chg; |
| 3024 | int ret, idx; |
| 3025 | struct hugetlb_cgroup *h_cg; |
| 3026 | bool deferred_reserve; |
| 3027 | |
| 3028 | idx = hstate_index(h); |
| 3029 | /* |
| 3030 | * Examine the region/reserve map to determine if the process |
| 3031 | * has a reservation for the page to be allocated. A return |
| 3032 | * code of zero indicates a reservation exists (no change). |
| 3033 | */ |
| 3034 | map_chg = gbl_chg = vma_needs_reservation(h, vma, addr); |
| 3035 | if (map_chg < 0) |
| 3036 | return ERR_PTR(-ENOMEM); |
| 3037 | |
| 3038 | /* |
| 3039 | * Processes that did not create the mapping will have no |
| 3040 | * reserves as indicated by the region/reserve map. Check |
| 3041 | * that the allocation will not exceed the subpool limit. |
| 3042 | * Allocations for MAP_NORESERVE mappings also need to be |
| 3043 | * checked against any subpool limit. |
| 3044 | */ |
| 3045 | if (map_chg || avoid_reserve) { |
| 3046 | gbl_chg = hugepage_subpool_get_pages(spool, 1); |
| 3047 | if (gbl_chg < 0) { |
| 3048 | vma_end_reservation(h, vma, addr); |
| 3049 | return ERR_PTR(-ENOSPC); |
| 3050 | } |
| 3051 | |
| 3052 | /* |
| 3053 | * Even though there was no reservation in the region/reserve |
| 3054 | * map, there could be reservations associated with the |
| 3055 | * subpool that can be used. This would be indicated if the |
| 3056 | * return value of hugepage_subpool_get_pages() is zero. |
| 3057 | * However, if avoid_reserve is specified we still avoid even |
| 3058 | * the subpool reservations. |
| 3059 | */ |
| 3060 | if (avoid_reserve) |
| 3061 | gbl_chg = 1; |
| 3062 | } |
| 3063 | |
| 3064 | /* If this allocation is not consuming a reservation, charge it now. |
| 3065 | */ |
| 3066 | deferred_reserve = map_chg || avoid_reserve; |
| 3067 | if (deferred_reserve) { |
| 3068 | ret = hugetlb_cgroup_charge_cgroup_rsvd( |
| 3069 | idx, pages_per_huge_page(h), &h_cg); |
| 3070 | if (ret) |
| 3071 | goto out_subpool_put; |
| 3072 | } |
| 3073 | |
| 3074 | ret = hugetlb_cgroup_charge_cgroup(idx, pages_per_huge_page(h), &h_cg); |
| 3075 | if (ret) |
| 3076 | goto out_uncharge_cgroup_reservation; |
| 3077 | |
| 3078 | spin_lock_irq(&hugetlb_lock); |
| 3079 | /* |
| 3080 | * glb_chg is passed to indicate whether or not a page must be taken |
| 3081 | * from the global free pool (global change). gbl_chg == 0 indicates |
| 3082 | * a reservation exists for the allocation. |
| 3083 | */ |
| 3084 | page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve, gbl_chg); |
| 3085 | if (!page) { |
| 3086 | spin_unlock_irq(&hugetlb_lock); |
| 3087 | page = alloc_buddy_huge_page_with_mpol(h, vma, addr); |
| 3088 | if (!page) |
| 3089 | goto out_uncharge_cgroup; |
| 3090 | spin_lock_irq(&hugetlb_lock); |
| 3091 | if (!avoid_reserve && vma_has_reserves(vma, gbl_chg)) { |
| 3092 | SetHPageRestoreReserve(page); |
| 3093 | h->resv_huge_pages--; |
| 3094 | } |
| 3095 | list_add(&page->lru, &h->hugepage_activelist); |
| 3096 | set_page_refcounted(page); |
| 3097 | /* Fall through */ |
| 3098 | } |
| 3099 | folio = page_folio(page); |
| 3100 | hugetlb_cgroup_commit_charge(idx, pages_per_huge_page(h), h_cg, page); |
| 3101 | /* If allocation is not consuming a reservation, also store the |
| 3102 | * hugetlb_cgroup pointer on the page. |
| 3103 | */ |
| 3104 | if (deferred_reserve) { |
| 3105 | hugetlb_cgroup_commit_charge_rsvd(idx, pages_per_huge_page(h), |
| 3106 | h_cg, page); |
| 3107 | } |
| 3108 | |
| 3109 | spin_unlock_irq(&hugetlb_lock); |
| 3110 | |
| 3111 | hugetlb_set_page_subpool(page, spool); |
| 3112 | |
| 3113 | map_commit = vma_commit_reservation(h, vma, addr); |
| 3114 | if (unlikely(map_chg > map_commit)) { |
| 3115 | /* |
| 3116 | * The page was added to the reservation map between |
| 3117 | * vma_needs_reservation and vma_commit_reservation. |
| 3118 | * This indicates a race with hugetlb_reserve_pages. |
| 3119 | * Adjust for the subpool count incremented above AND |
| 3120 | * in hugetlb_reserve_pages for the same page. Also, |
| 3121 | * the reservation count added in hugetlb_reserve_pages |
| 3122 | * no longer applies. |
| 3123 | */ |
| 3124 | long rsv_adjust; |
| 3125 | |
| 3126 | rsv_adjust = hugepage_subpool_put_pages(spool, 1); |
| 3127 | hugetlb_acct_memory(h, -rsv_adjust); |
| 3128 | if (deferred_reserve) |
| 3129 | hugetlb_cgroup_uncharge_folio_rsvd(hstate_index(h), |
| 3130 | pages_per_huge_page(h), folio); |
| 3131 | } |
| 3132 | return page; |
| 3133 | |
| 3134 | out_uncharge_cgroup: |
| 3135 | hugetlb_cgroup_uncharge_cgroup(idx, pages_per_huge_page(h), h_cg); |
| 3136 | out_uncharge_cgroup_reservation: |
| 3137 | if (deferred_reserve) |
| 3138 | hugetlb_cgroup_uncharge_cgroup_rsvd(idx, pages_per_huge_page(h), |
| 3139 | h_cg); |
| 3140 | out_subpool_put: |
| 3141 | if (map_chg || avoid_reserve) |
| 3142 | hugepage_subpool_put_pages(spool, 1); |
| 3143 | vma_end_reservation(h, vma, addr); |
| 3144 | return ERR_PTR(-ENOSPC); |
| 3145 | } |
| 3146 | |
| 3147 | int alloc_bootmem_huge_page(struct hstate *h, int nid) |
| 3148 | __attribute__ ((weak, alias("__alloc_bootmem_huge_page"))); |
| 3149 | int __alloc_bootmem_huge_page(struct hstate *h, int nid) |
| 3150 | { |
| 3151 | struct huge_bootmem_page *m = NULL; /* initialize for clang */ |
| 3152 | int nr_nodes, node; |
| 3153 | |
| 3154 | /* do node specific alloc */ |
| 3155 | if (nid != NUMA_NO_NODE) { |
| 3156 | m = memblock_alloc_try_nid_raw(huge_page_size(h), huge_page_size(h), |
| 3157 | 0, MEMBLOCK_ALLOC_ACCESSIBLE, nid); |
| 3158 | if (!m) |
| 3159 | return 0; |
| 3160 | goto found; |
| 3161 | } |
| 3162 | /* allocate from next node when distributing huge pages */ |
| 3163 | for_each_node_mask_to_alloc(h, nr_nodes, node, &node_states[N_MEMORY]) { |
| 3164 | m = memblock_alloc_try_nid_raw( |
| 3165 | huge_page_size(h), huge_page_size(h), |
| 3166 | 0, MEMBLOCK_ALLOC_ACCESSIBLE, node); |
| 3167 | /* |
| 3168 | * Use the beginning of the huge page to store the |
| 3169 | * huge_bootmem_page struct (until gather_bootmem |
| 3170 | * puts them into the mem_map). |
| 3171 | */ |
| 3172 | if (!m) |
| 3173 | return 0; |
| 3174 | goto found; |
| 3175 | } |
| 3176 | |
| 3177 | found: |
| 3178 | /* Put them into a private list first because mem_map is not up yet */ |
| 3179 | INIT_LIST_HEAD(&m->list); |
| 3180 | list_add(&m->list, &huge_boot_pages); |
| 3181 | m->hstate = h; |
| 3182 | return 1; |
| 3183 | } |
| 3184 | |
| 3185 | /* |
| 3186 | * Put bootmem huge pages into the standard lists after mem_map is up. |
| 3187 | * Note: This only applies to gigantic (order > MAX_ORDER) pages. |
| 3188 | */ |
| 3189 | static void __init gather_bootmem_prealloc(void) |
| 3190 | { |
| 3191 | struct huge_bootmem_page *m; |
| 3192 | |
| 3193 | list_for_each_entry(m, &huge_boot_pages, list) { |
| 3194 | struct page *page = virt_to_page(m); |
| 3195 | struct folio *folio = page_folio(page); |
| 3196 | struct hstate *h = m->hstate; |
| 3197 | |
| 3198 | VM_BUG_ON(!hstate_is_gigantic(h)); |
| 3199 | WARN_ON(folio_ref_count(folio) != 1); |
| 3200 | if (prep_compound_gigantic_folio(folio, huge_page_order(h))) { |
| 3201 | WARN_ON(folio_test_reserved(folio)); |
| 3202 | prep_new_hugetlb_folio(h, folio, folio_nid(folio)); |
| 3203 | free_huge_page(page); /* add to the hugepage allocator */ |
| 3204 | } else { |
| 3205 | /* VERY unlikely inflated ref count on a tail page */ |
| 3206 | free_gigantic_folio(folio, huge_page_order(h)); |
| 3207 | } |
| 3208 | |
| 3209 | /* |
| 3210 | * We need to restore the 'stolen' pages to totalram_pages |
| 3211 | * in order to fix confusing memory reports from free(1) and |
| 3212 | * other side-effects, like CommitLimit going negative. |
| 3213 | */ |
| 3214 | adjust_managed_page_count(page, pages_per_huge_page(h)); |
| 3215 | cond_resched(); |
| 3216 | } |
| 3217 | } |
| 3218 | static void __init hugetlb_hstate_alloc_pages_onenode(struct hstate *h, int nid) |
| 3219 | { |
| 3220 | unsigned long i; |
| 3221 | char buf[32]; |
| 3222 | |
| 3223 | for (i = 0; i < h->max_huge_pages_node[nid]; ++i) { |
| 3224 | if (hstate_is_gigantic(h)) { |
| 3225 | if (!alloc_bootmem_huge_page(h, nid)) |
| 3226 | break; |
| 3227 | } else { |
| 3228 | struct folio *folio; |
| 3229 | gfp_t gfp_mask = htlb_alloc_mask(h) | __GFP_THISNODE; |
| 3230 | |
| 3231 | folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, |
| 3232 | &node_states[N_MEMORY], NULL); |
| 3233 | if (!folio) |
| 3234 | break; |
| 3235 | free_huge_page(&folio->page); /* free it into the hugepage allocator */ |
| 3236 | } |
| 3237 | cond_resched(); |
| 3238 | } |
| 3239 | if (i == h->max_huge_pages_node[nid]) |
| 3240 | return; |
| 3241 | |
| 3242 | string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
| 3243 | pr_warn("HugeTLB: allocating %u of page size %s failed node%d. Only allocated %lu hugepages.\n", |
| 3244 | h->max_huge_pages_node[nid], buf, nid, i); |
| 3245 | h->max_huge_pages -= (h->max_huge_pages_node[nid] - i); |
| 3246 | h->max_huge_pages_node[nid] = i; |
| 3247 | } |
| 3248 | |
| 3249 | static void __init hugetlb_hstate_alloc_pages(struct hstate *h) |
| 3250 | { |
| 3251 | unsigned long i; |
| 3252 | nodemask_t *node_alloc_noretry; |
| 3253 | bool node_specific_alloc = false; |
| 3254 | |
| 3255 | /* skip gigantic hugepages allocation if hugetlb_cma enabled */ |
| 3256 | if (hstate_is_gigantic(h) && hugetlb_cma_size) { |
| 3257 | pr_warn_once("HugeTLB: hugetlb_cma is enabled, skip boot time allocation\n"); |
| 3258 | return; |
| 3259 | } |
| 3260 | |
| 3261 | /* do node specific alloc */ |
| 3262 | for_each_online_node(i) { |
| 3263 | if (h->max_huge_pages_node[i] > 0) { |
| 3264 | hugetlb_hstate_alloc_pages_onenode(h, i); |
| 3265 | node_specific_alloc = true; |
| 3266 | } |
| 3267 | } |
| 3268 | |
| 3269 | if (node_specific_alloc) |
| 3270 | return; |
| 3271 | |
| 3272 | /* below will do all node balanced alloc */ |
| 3273 | if (!hstate_is_gigantic(h)) { |
| 3274 | /* |
| 3275 | * Bit mask controlling how hard we retry per-node allocations. |
| 3276 | * Ignore errors as lower level routines can deal with |
| 3277 | * node_alloc_noretry == NULL. If this kmalloc fails at boot |
| 3278 | * time, we are likely in bigger trouble. |
| 3279 | */ |
| 3280 | node_alloc_noretry = kmalloc(sizeof(*node_alloc_noretry), |
| 3281 | GFP_KERNEL); |
| 3282 | } else { |
| 3283 | /* allocations done at boot time */ |
| 3284 | node_alloc_noretry = NULL; |
| 3285 | } |
| 3286 | |
| 3287 | /* bit mask controlling how hard we retry per-node allocations */ |
| 3288 | if (node_alloc_noretry) |
| 3289 | nodes_clear(*node_alloc_noretry); |
| 3290 | |
| 3291 | for (i = 0; i < h->max_huge_pages; ++i) { |
| 3292 | if (hstate_is_gigantic(h)) { |
| 3293 | if (!alloc_bootmem_huge_page(h, NUMA_NO_NODE)) |
| 3294 | break; |
| 3295 | } else if (!alloc_pool_huge_page(h, |
| 3296 | &node_states[N_MEMORY], |
| 3297 | node_alloc_noretry)) |
| 3298 | break; |
| 3299 | cond_resched(); |
| 3300 | } |
| 3301 | if (i < h->max_huge_pages) { |
| 3302 | char buf[32]; |
| 3303 | |
| 3304 | string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
| 3305 | pr_warn("HugeTLB: allocating %lu of page size %s failed. Only allocated %lu hugepages.\n", |
| 3306 | h->max_huge_pages, buf, i); |
| 3307 | h->max_huge_pages = i; |
| 3308 | } |
| 3309 | kfree(node_alloc_noretry); |
| 3310 | } |
| 3311 | |
| 3312 | static void __init hugetlb_init_hstates(void) |
| 3313 | { |
| 3314 | struct hstate *h, *h2; |
| 3315 | |
| 3316 | for_each_hstate(h) { |
| 3317 | /* oversize hugepages were init'ed in early boot */ |
| 3318 | if (!hstate_is_gigantic(h)) |
| 3319 | hugetlb_hstate_alloc_pages(h); |
| 3320 | |
| 3321 | /* |
| 3322 | * Set demote order for each hstate. Note that |
| 3323 | * h->demote_order is initially 0. |
| 3324 | * - We can not demote gigantic pages if runtime freeing |
| 3325 | * is not supported, so skip this. |
| 3326 | * - If CMA allocation is possible, we can not demote |
| 3327 | * HUGETLB_PAGE_ORDER or smaller size pages. |
| 3328 | */ |
| 3329 | if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| 3330 | continue; |
| 3331 | if (hugetlb_cma_size && h->order <= HUGETLB_PAGE_ORDER) |
| 3332 | continue; |
| 3333 | for_each_hstate(h2) { |
| 3334 | if (h2 == h) |
| 3335 | continue; |
| 3336 | if (h2->order < h->order && |
| 3337 | h2->order > h->demote_order) |
| 3338 | h->demote_order = h2->order; |
| 3339 | } |
| 3340 | } |
| 3341 | } |
| 3342 | |
| 3343 | static void __init report_hugepages(void) |
| 3344 | { |
| 3345 | struct hstate *h; |
| 3346 | |
| 3347 | for_each_hstate(h) { |
| 3348 | char buf[32]; |
| 3349 | |
| 3350 | string_get_size(huge_page_size(h), 1, STRING_UNITS_2, buf, 32); |
| 3351 | pr_info("HugeTLB: registered %s page size, pre-allocated %ld pages\n", |
| 3352 | buf, h->free_huge_pages); |
| 3353 | pr_info("HugeTLB: %d KiB vmemmap can be freed for a %s page\n", |
| 3354 | hugetlb_vmemmap_optimizable_size(h) / SZ_1K, buf); |
| 3355 | } |
| 3356 | } |
| 3357 | |
| 3358 | #ifdef CONFIG_HIGHMEM |
| 3359 | static void try_to_free_low(struct hstate *h, unsigned long count, |
| 3360 | nodemask_t *nodes_allowed) |
| 3361 | { |
| 3362 | int i; |
| 3363 | LIST_HEAD(page_list); |
| 3364 | |
| 3365 | lockdep_assert_held(&hugetlb_lock); |
| 3366 | if (hstate_is_gigantic(h)) |
| 3367 | return; |
| 3368 | |
| 3369 | /* |
| 3370 | * Collect pages to be freed on a list, and free after dropping lock |
| 3371 | */ |
| 3372 | for_each_node_mask(i, *nodes_allowed) { |
| 3373 | struct page *page, *next; |
| 3374 | struct list_head *freel = &h->hugepage_freelists[i]; |
| 3375 | list_for_each_entry_safe(page, next, freel, lru) { |
| 3376 | if (count >= h->nr_huge_pages) |
| 3377 | goto out; |
| 3378 | if (PageHighMem(page)) |
| 3379 | continue; |
| 3380 | remove_hugetlb_folio(h, page_folio(page), false); |
| 3381 | list_add(&page->lru, &page_list); |
| 3382 | } |
| 3383 | } |
| 3384 | |
| 3385 | out: |
| 3386 | spin_unlock_irq(&hugetlb_lock); |
| 3387 | update_and_free_pages_bulk(h, &page_list); |
| 3388 | spin_lock_irq(&hugetlb_lock); |
| 3389 | } |
| 3390 | #else |
| 3391 | static inline void try_to_free_low(struct hstate *h, unsigned long count, |
| 3392 | nodemask_t *nodes_allowed) |
| 3393 | { |
| 3394 | } |
| 3395 | #endif |
| 3396 | |
| 3397 | /* |
| 3398 | * Increment or decrement surplus_huge_pages. Keep node-specific counters |
| 3399 | * balanced by operating on them in a round-robin fashion. |
| 3400 | * Returns 1 if an adjustment was made. |
| 3401 | */ |
| 3402 | static int adjust_pool_surplus(struct hstate *h, nodemask_t *nodes_allowed, |
| 3403 | int delta) |
| 3404 | { |
| 3405 | int nr_nodes, node; |
| 3406 | |
| 3407 | lockdep_assert_held(&hugetlb_lock); |
| 3408 | VM_BUG_ON(delta != -1 && delta != 1); |
| 3409 | |
| 3410 | if (delta < 0) { |
| 3411 | for_each_node_mask_to_alloc(h, nr_nodes, node, nodes_allowed) { |
| 3412 | if (h->surplus_huge_pages_node[node]) |
| 3413 | goto found; |
| 3414 | } |
| 3415 | } else { |
| 3416 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
| 3417 | if (h->surplus_huge_pages_node[node] < |
| 3418 | h->nr_huge_pages_node[node]) |
| 3419 | goto found; |
| 3420 | } |
| 3421 | } |
| 3422 | return 0; |
| 3423 | |
| 3424 | found: |
| 3425 | h->surplus_huge_pages += delta; |
| 3426 | h->surplus_huge_pages_node[node] += delta; |
| 3427 | return 1; |
| 3428 | } |
| 3429 | |
| 3430 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
| 3431 | static int set_max_huge_pages(struct hstate *h, unsigned long count, int nid, |
| 3432 | nodemask_t *nodes_allowed) |
| 3433 | { |
| 3434 | unsigned long min_count, ret; |
| 3435 | struct page *page; |
| 3436 | LIST_HEAD(page_list); |
| 3437 | NODEMASK_ALLOC(nodemask_t, node_alloc_noretry, GFP_KERNEL); |
| 3438 | |
| 3439 | /* |
| 3440 | * Bit mask controlling how hard we retry per-node allocations. |
| 3441 | * If we can not allocate the bit mask, do not attempt to allocate |
| 3442 | * the requested huge pages. |
| 3443 | */ |
| 3444 | if (node_alloc_noretry) |
| 3445 | nodes_clear(*node_alloc_noretry); |
| 3446 | else |
| 3447 | return -ENOMEM; |
| 3448 | |
| 3449 | /* |
| 3450 | * resize_lock mutex prevents concurrent adjustments to number of |
| 3451 | * pages in hstate via the proc/sysfs interfaces. |
| 3452 | */ |
| 3453 | mutex_lock(&h->resize_lock); |
| 3454 | flush_free_hpage_work(h); |
| 3455 | spin_lock_irq(&hugetlb_lock); |
| 3456 | |
| 3457 | /* |
| 3458 | * Check for a node specific request. |
| 3459 | * Changing node specific huge page count may require a corresponding |
| 3460 | * change to the global count. In any case, the passed node mask |
| 3461 | * (nodes_allowed) will restrict alloc/free to the specified node. |
| 3462 | */ |
| 3463 | if (nid != NUMA_NO_NODE) { |
| 3464 | unsigned long old_count = count; |
| 3465 | |
| 3466 | count += h->nr_huge_pages - h->nr_huge_pages_node[nid]; |
| 3467 | /* |
| 3468 | * User may have specified a large count value which caused the |
| 3469 | * above calculation to overflow. In this case, they wanted |
| 3470 | * to allocate as many huge pages as possible. Set count to |
| 3471 | * largest possible value to align with their intention. |
| 3472 | */ |
| 3473 | if (count < old_count) |
| 3474 | count = ULONG_MAX; |
| 3475 | } |
| 3476 | |
| 3477 | /* |
| 3478 | * Gigantic pages runtime allocation depend on the capability for large |
| 3479 | * page range allocation. |
| 3480 | * If the system does not provide this feature, return an error when |
| 3481 | * the user tries to allocate gigantic pages but let the user free the |
| 3482 | * boottime allocated gigantic pages. |
| 3483 | */ |
| 3484 | if (hstate_is_gigantic(h) && !IS_ENABLED(CONFIG_CONTIG_ALLOC)) { |
| 3485 | if (count > persistent_huge_pages(h)) { |
| 3486 | spin_unlock_irq(&hugetlb_lock); |
| 3487 | mutex_unlock(&h->resize_lock); |
| 3488 | NODEMASK_FREE(node_alloc_noretry); |
| 3489 | return -EINVAL; |
| 3490 | } |
| 3491 | /* Fall through to decrease pool */ |
| 3492 | } |
| 3493 | |
| 3494 | /* |
| 3495 | * Increase the pool size |
| 3496 | * First take pages out of surplus state. Then make up the |
| 3497 | * remaining difference by allocating fresh huge pages. |
| 3498 | * |
| 3499 | * We might race with alloc_surplus_huge_page() here and be unable |
| 3500 | * to convert a surplus huge page to a normal huge page. That is |
| 3501 | * not critical, though, it just means the overall size of the |
| 3502 | * pool might be one hugepage larger than it needs to be, but |
| 3503 | * within all the constraints specified by the sysctls. |
| 3504 | */ |
| 3505 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
| 3506 | if (!adjust_pool_surplus(h, nodes_allowed, -1)) |
| 3507 | break; |
| 3508 | } |
| 3509 | |
| 3510 | while (count > persistent_huge_pages(h)) { |
| 3511 | /* |
| 3512 | * If this allocation races such that we no longer need the |
| 3513 | * page, free_huge_page will handle it by freeing the page |
| 3514 | * and reducing the surplus. |
| 3515 | */ |
| 3516 | spin_unlock_irq(&hugetlb_lock); |
| 3517 | |
| 3518 | /* yield cpu to avoid soft lockup */ |
| 3519 | cond_resched(); |
| 3520 | |
| 3521 | ret = alloc_pool_huge_page(h, nodes_allowed, |
| 3522 | node_alloc_noretry); |
| 3523 | spin_lock_irq(&hugetlb_lock); |
| 3524 | if (!ret) |
| 3525 | goto out; |
| 3526 | |
| 3527 | /* Bail for signals. Probably ctrl-c from user */ |
| 3528 | if (signal_pending(current)) |
| 3529 | goto out; |
| 3530 | } |
| 3531 | |
| 3532 | /* |
| 3533 | * Decrease the pool size |
| 3534 | * First return free pages to the buddy allocator (being careful |
| 3535 | * to keep enough around to satisfy reservations). Then place |
| 3536 | * pages into surplus state as needed so the pool will shrink |
| 3537 | * to the desired size as pages become free. |
| 3538 | * |
| 3539 | * By placing pages into the surplus state independent of the |
| 3540 | * overcommit value, we are allowing the surplus pool size to |
| 3541 | * exceed overcommit. There are few sane options here. Since |
| 3542 | * alloc_surplus_huge_page() is checking the global counter, |
| 3543 | * though, we'll note that we're not allowed to exceed surplus |
| 3544 | * and won't grow the pool anywhere else. Not until one of the |
| 3545 | * sysctls are changed, or the surplus pages go out of use. |
| 3546 | */ |
| 3547 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
| 3548 | min_count = max(count, min_count); |
| 3549 | try_to_free_low(h, min_count, nodes_allowed); |
| 3550 | |
| 3551 | /* |
| 3552 | * Collect pages to be removed on list without dropping lock |
| 3553 | */ |
| 3554 | while (min_count < persistent_huge_pages(h)) { |
| 3555 | page = remove_pool_huge_page(h, nodes_allowed, 0); |
| 3556 | if (!page) |
| 3557 | break; |
| 3558 | |
| 3559 | list_add(&page->lru, &page_list); |
| 3560 | } |
| 3561 | /* free the pages after dropping lock */ |
| 3562 | spin_unlock_irq(&hugetlb_lock); |
| 3563 | update_and_free_pages_bulk(h, &page_list); |
| 3564 | flush_free_hpage_work(h); |
| 3565 | spin_lock_irq(&hugetlb_lock); |
| 3566 | |
| 3567 | while (count < persistent_huge_pages(h)) { |
| 3568 | if (!adjust_pool_surplus(h, nodes_allowed, 1)) |
| 3569 | break; |
| 3570 | } |
| 3571 | out: |
| 3572 | h->max_huge_pages = persistent_huge_pages(h); |
| 3573 | spin_unlock_irq(&hugetlb_lock); |
| 3574 | mutex_unlock(&h->resize_lock); |
| 3575 | |
| 3576 | NODEMASK_FREE(node_alloc_noretry); |
| 3577 | |
| 3578 | return 0; |
| 3579 | } |
| 3580 | |
| 3581 | static int demote_free_huge_page(struct hstate *h, struct page *page) |
| 3582 | { |
| 3583 | int i, nid = page_to_nid(page); |
| 3584 | struct hstate *target_hstate; |
| 3585 | struct folio *folio = page_folio(page); |
| 3586 | struct page *subpage; |
| 3587 | int rc = 0; |
| 3588 | |
| 3589 | target_hstate = size_to_hstate(PAGE_SIZE << h->demote_order); |
| 3590 | |
| 3591 | remove_hugetlb_folio_for_demote(h, folio, false); |
| 3592 | spin_unlock_irq(&hugetlb_lock); |
| 3593 | |
| 3594 | rc = hugetlb_vmemmap_restore(h, page); |
| 3595 | if (rc) { |
| 3596 | /* Allocation of vmemmmap failed, we can not demote page */ |
| 3597 | spin_lock_irq(&hugetlb_lock); |
| 3598 | set_page_refcounted(page); |
| 3599 | add_hugetlb_folio(h, page_folio(page), false); |
| 3600 | return rc; |
| 3601 | } |
| 3602 | |
| 3603 | /* |
| 3604 | * Use destroy_compound_hugetlb_folio_for_demote for all huge page |
| 3605 | * sizes as it will not ref count pages. |
| 3606 | */ |
| 3607 | destroy_compound_hugetlb_folio_for_demote(folio, huge_page_order(h)); |
| 3608 | |
| 3609 | /* |
| 3610 | * Taking target hstate mutex synchronizes with set_max_huge_pages. |
| 3611 | * Without the mutex, pages added to target hstate could be marked |
| 3612 | * as surplus. |
| 3613 | * |
| 3614 | * Note that we already hold h->resize_lock. To prevent deadlock, |
| 3615 | * use the convention of always taking larger size hstate mutex first. |
| 3616 | */ |
| 3617 | mutex_lock(&target_hstate->resize_lock); |
| 3618 | for (i = 0; i < pages_per_huge_page(h); |
| 3619 | i += pages_per_huge_page(target_hstate)) { |
| 3620 | subpage = nth_page(page, i); |
| 3621 | folio = page_folio(subpage); |
| 3622 | if (hstate_is_gigantic(target_hstate)) |
| 3623 | prep_compound_gigantic_folio_for_demote(folio, |
| 3624 | target_hstate->order); |
| 3625 | else |
| 3626 | prep_compound_page(subpage, target_hstate->order); |
| 3627 | set_page_private(subpage, 0); |
| 3628 | prep_new_hugetlb_folio(target_hstate, folio, nid); |
| 3629 | free_huge_page(subpage); |
| 3630 | } |
| 3631 | mutex_unlock(&target_hstate->resize_lock); |
| 3632 | |
| 3633 | spin_lock_irq(&hugetlb_lock); |
| 3634 | |
| 3635 | /* |
| 3636 | * Not absolutely necessary, but for consistency update max_huge_pages |
| 3637 | * based on pool changes for the demoted page. |
| 3638 | */ |
| 3639 | h->max_huge_pages--; |
| 3640 | target_hstate->max_huge_pages += |
| 3641 | pages_per_huge_page(h) / pages_per_huge_page(target_hstate); |
| 3642 | |
| 3643 | return rc; |
| 3644 | } |
| 3645 | |
| 3646 | static int demote_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed) |
| 3647 | __must_hold(&hugetlb_lock) |
| 3648 | { |
| 3649 | int nr_nodes, node; |
| 3650 | struct page *page; |
| 3651 | |
| 3652 | lockdep_assert_held(&hugetlb_lock); |
| 3653 | |
| 3654 | /* We should never get here if no demote order */ |
| 3655 | if (!h->demote_order) { |
| 3656 | pr_warn("HugeTLB: NULL demote order passed to demote_pool_huge_page.\n"); |
| 3657 | return -EINVAL; /* internal error */ |
| 3658 | } |
| 3659 | |
| 3660 | for_each_node_mask_to_free(h, nr_nodes, node, nodes_allowed) { |
| 3661 | list_for_each_entry(page, &h->hugepage_freelists[node], lru) { |
| 3662 | if (PageHWPoison(page)) |
| 3663 | continue; |
| 3664 | |
| 3665 | return demote_free_huge_page(h, page); |
| 3666 | } |
| 3667 | } |
| 3668 | |
| 3669 | /* |
| 3670 | * Only way to get here is if all pages on free lists are poisoned. |
| 3671 | * Return -EBUSY so that caller will not retry. |
| 3672 | */ |
| 3673 | return -EBUSY; |
| 3674 | } |
| 3675 | |
| 3676 | #define HSTATE_ATTR_RO(_name) \ |
| 3677 | static struct kobj_attribute _name##_attr = __ATTR_RO(_name) |
| 3678 | |
| 3679 | #define HSTATE_ATTR_WO(_name) \ |
| 3680 | static struct kobj_attribute _name##_attr = __ATTR_WO(_name) |
| 3681 | |
| 3682 | #define HSTATE_ATTR(_name) \ |
| 3683 | static struct kobj_attribute _name##_attr = __ATTR_RW(_name) |
| 3684 | |
| 3685 | static struct kobject *hugepages_kobj; |
| 3686 | static struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
| 3687 | |
| 3688 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp); |
| 3689 | |
| 3690 | static struct hstate *kobj_to_hstate(struct kobject *kobj, int *nidp) |
| 3691 | { |
| 3692 | int i; |
| 3693 | |
| 3694 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
| 3695 | if (hstate_kobjs[i] == kobj) { |
| 3696 | if (nidp) |
| 3697 | *nidp = NUMA_NO_NODE; |
| 3698 | return &hstates[i]; |
| 3699 | } |
| 3700 | |
| 3701 | return kobj_to_node_hstate(kobj, nidp); |
| 3702 | } |
| 3703 | |
| 3704 | static ssize_t nr_hugepages_show_common(struct kobject *kobj, |
| 3705 | struct kobj_attribute *attr, char *buf) |
| 3706 | { |
| 3707 | struct hstate *h; |
| 3708 | unsigned long nr_huge_pages; |
| 3709 | int nid; |
| 3710 | |
| 3711 | h = kobj_to_hstate(kobj, &nid); |
| 3712 | if (nid == NUMA_NO_NODE) |
| 3713 | nr_huge_pages = h->nr_huge_pages; |
| 3714 | else |
| 3715 | nr_huge_pages = h->nr_huge_pages_node[nid]; |
| 3716 | |
| 3717 | return sysfs_emit(buf, "%lu\n", nr_huge_pages); |
| 3718 | } |
| 3719 | |
| 3720 | static ssize_t __nr_hugepages_store_common(bool obey_mempolicy, |
| 3721 | struct hstate *h, int nid, |
| 3722 | unsigned long count, size_t len) |
| 3723 | { |
| 3724 | int err; |
| 3725 | nodemask_t nodes_allowed, *n_mask; |
| 3726 | |
| 3727 | if (hstate_is_gigantic(h) && !gigantic_page_runtime_supported()) |
| 3728 | return -EINVAL; |
| 3729 | |
| 3730 | if (nid == NUMA_NO_NODE) { |
| 3731 | /* |
| 3732 | * global hstate attribute |
| 3733 | */ |
| 3734 | if (!(obey_mempolicy && |
| 3735 | init_nodemask_of_mempolicy(&nodes_allowed))) |
| 3736 | n_mask = &node_states[N_MEMORY]; |
| 3737 | else |
| 3738 | n_mask = &nodes_allowed; |
| 3739 | } else { |
| 3740 | /* |
| 3741 | * Node specific request. count adjustment happens in |
| 3742 | * set_max_huge_pages() after acquiring hugetlb_lock. |
| 3743 | */ |
| 3744 | init_nodemask_of_node(&nodes_allowed, nid); |
| 3745 | n_mask = &nodes_allowed; |
| 3746 | } |
| 3747 | |
| 3748 | err = set_max_huge_pages(h, count, nid, n_mask); |
| 3749 | |
| 3750 | return err ? err : len; |
| 3751 | } |
| 3752 | |
| 3753 | static ssize_t nr_hugepages_store_common(bool obey_mempolicy, |
| 3754 | struct kobject *kobj, const char *buf, |
| 3755 | size_t len) |
| 3756 | { |
| 3757 | struct hstate *h; |
| 3758 | unsigned long count; |
| 3759 | int nid; |
| 3760 | int err; |
| 3761 | |
| 3762 | err = kstrtoul(buf, 10, &count); |
| 3763 | if (err) |
| 3764 | return err; |
| 3765 | |
| 3766 | h = kobj_to_hstate(kobj, &nid); |
| 3767 | return __nr_hugepages_store_common(obey_mempolicy, h, nid, count, len); |
| 3768 | } |
| 3769 | |
| 3770 | static ssize_t nr_hugepages_show(struct kobject *kobj, |
| 3771 | struct kobj_attribute *attr, char *buf) |
| 3772 | { |
| 3773 | return nr_hugepages_show_common(kobj, attr, buf); |
| 3774 | } |
| 3775 | |
| 3776 | static ssize_t nr_hugepages_store(struct kobject *kobj, |
| 3777 | struct kobj_attribute *attr, const char *buf, size_t len) |
| 3778 | { |
| 3779 | return nr_hugepages_store_common(false, kobj, buf, len); |
| 3780 | } |
| 3781 | HSTATE_ATTR(nr_hugepages); |
| 3782 | |
| 3783 | #ifdef CONFIG_NUMA |
| 3784 | |
| 3785 | /* |
| 3786 | * hstate attribute for optionally mempolicy-based constraint on persistent |
| 3787 | * huge page alloc/free. |
| 3788 | */ |
| 3789 | static ssize_t nr_hugepages_mempolicy_show(struct kobject *kobj, |
| 3790 | struct kobj_attribute *attr, |
| 3791 | char *buf) |
| 3792 | { |
| 3793 | return nr_hugepages_show_common(kobj, attr, buf); |
| 3794 | } |
| 3795 | |
| 3796 | static ssize_t nr_hugepages_mempolicy_store(struct kobject *kobj, |
| 3797 | struct kobj_attribute *attr, const char *buf, size_t len) |
| 3798 | { |
| 3799 | return nr_hugepages_store_common(true, kobj, buf, len); |
| 3800 | } |
| 3801 | HSTATE_ATTR(nr_hugepages_mempolicy); |
| 3802 | #endif |
| 3803 | |
| 3804 | |
| 3805 | static ssize_t nr_overcommit_hugepages_show(struct kobject *kobj, |
| 3806 | struct kobj_attribute *attr, char *buf) |
| 3807 | { |
| 3808 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
| 3809 | return sysfs_emit(buf, "%lu\n", h->nr_overcommit_huge_pages); |
| 3810 | } |
| 3811 | |
| 3812 | static ssize_t nr_overcommit_hugepages_store(struct kobject *kobj, |
| 3813 | struct kobj_attribute *attr, const char *buf, size_t count) |
| 3814 | { |
| 3815 | int err; |
| 3816 | unsigned long input; |
| 3817 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
| 3818 | |
| 3819 | if (hstate_is_gigantic(h)) |
| 3820 | return -EINVAL; |
| 3821 | |
| 3822 | err = kstrtoul(buf, 10, &input); |
| 3823 | if (err) |
| 3824 | return err; |
| 3825 | |
| 3826 | spin_lock_irq(&hugetlb_lock); |
| 3827 | h->nr_overcommit_huge_pages = input; |
| 3828 | spin_unlock_irq(&hugetlb_lock); |
| 3829 | |
| 3830 | return count; |
| 3831 | } |
| 3832 | HSTATE_ATTR(nr_overcommit_hugepages); |
| 3833 | |
| 3834 | static ssize_t free_hugepages_show(struct kobject *kobj, |
| 3835 | struct kobj_attribute *attr, char *buf) |
| 3836 | { |
| 3837 | struct hstate *h; |
| 3838 | unsigned long free_huge_pages; |
| 3839 | int nid; |
| 3840 | |
| 3841 | h = kobj_to_hstate(kobj, &nid); |
| 3842 | if (nid == NUMA_NO_NODE) |
| 3843 | free_huge_pages = h->free_huge_pages; |
| 3844 | else |
| 3845 | free_huge_pages = h->free_huge_pages_node[nid]; |
| 3846 | |
| 3847 | return sysfs_emit(buf, "%lu\n", free_huge_pages); |
| 3848 | } |
| 3849 | HSTATE_ATTR_RO(free_hugepages); |
| 3850 | |
| 3851 | static ssize_t resv_hugepages_show(struct kobject *kobj, |
| 3852 | struct kobj_attribute *attr, char *buf) |
| 3853 | { |
| 3854 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
| 3855 | return sysfs_emit(buf, "%lu\n", h->resv_huge_pages); |
| 3856 | } |
| 3857 | HSTATE_ATTR_RO(resv_hugepages); |
| 3858 | |
| 3859 | static ssize_t surplus_hugepages_show(struct kobject *kobj, |
| 3860 | struct kobj_attribute *attr, char *buf) |
| 3861 | { |
| 3862 | struct hstate *h; |
| 3863 | unsigned long surplus_huge_pages; |
| 3864 | int nid; |
| 3865 | |
| 3866 | h = kobj_to_hstate(kobj, &nid); |
| 3867 | if (nid == NUMA_NO_NODE) |
| 3868 | surplus_huge_pages = h->surplus_huge_pages; |
| 3869 | else |
| 3870 | surplus_huge_pages = h->surplus_huge_pages_node[nid]; |
| 3871 | |
| 3872 | return sysfs_emit(buf, "%lu\n", surplus_huge_pages); |
| 3873 | } |
| 3874 | HSTATE_ATTR_RO(surplus_hugepages); |
| 3875 | |
| 3876 | static ssize_t demote_store(struct kobject *kobj, |
| 3877 | struct kobj_attribute *attr, const char *buf, size_t len) |
| 3878 | { |
| 3879 | unsigned long nr_demote; |
| 3880 | unsigned long nr_available; |
| 3881 | nodemask_t nodes_allowed, *n_mask; |
| 3882 | struct hstate *h; |
| 3883 | int err; |
| 3884 | int nid; |
| 3885 | |
| 3886 | err = kstrtoul(buf, 10, &nr_demote); |
| 3887 | if (err) |
| 3888 | return err; |
| 3889 | h = kobj_to_hstate(kobj, &nid); |
| 3890 | |
| 3891 | if (nid != NUMA_NO_NODE) { |
| 3892 | init_nodemask_of_node(&nodes_allowed, nid); |
| 3893 | n_mask = &nodes_allowed; |
| 3894 | } else { |
| 3895 | n_mask = &node_states[N_MEMORY]; |
| 3896 | } |
| 3897 | |
| 3898 | /* Synchronize with other sysfs operations modifying huge pages */ |
| 3899 | mutex_lock(&h->resize_lock); |
| 3900 | spin_lock_irq(&hugetlb_lock); |
| 3901 | |
| 3902 | while (nr_demote) { |
| 3903 | /* |
| 3904 | * Check for available pages to demote each time thorough the |
| 3905 | * loop as demote_pool_huge_page will drop hugetlb_lock. |
| 3906 | */ |
| 3907 | if (nid != NUMA_NO_NODE) |
| 3908 | nr_available = h->free_huge_pages_node[nid]; |
| 3909 | else |
| 3910 | nr_available = h->free_huge_pages; |
| 3911 | nr_available -= h->resv_huge_pages; |
| 3912 | if (!nr_available) |
| 3913 | break; |
| 3914 | |
| 3915 | err = demote_pool_huge_page(h, n_mask); |
| 3916 | if (err) |
| 3917 | break; |
| 3918 | |
| 3919 | nr_demote--; |
| 3920 | } |
| 3921 | |
| 3922 | spin_unlock_irq(&hugetlb_lock); |
| 3923 | mutex_unlock(&h->resize_lock); |
| 3924 | |
| 3925 | if (err) |
| 3926 | return err; |
| 3927 | return len; |
| 3928 | } |
| 3929 | HSTATE_ATTR_WO(demote); |
| 3930 | |
| 3931 | static ssize_t demote_size_show(struct kobject *kobj, |
| 3932 | struct kobj_attribute *attr, char *buf) |
| 3933 | { |
| 3934 | struct hstate *h = kobj_to_hstate(kobj, NULL); |
| 3935 | unsigned long demote_size = (PAGE_SIZE << h->demote_order) / SZ_1K; |
| 3936 | |
| 3937 | return sysfs_emit(buf, "%lukB\n", demote_size); |
| 3938 | } |
| 3939 | |
| 3940 | static ssize_t demote_size_store(struct kobject *kobj, |
| 3941 | struct kobj_attribute *attr, |
| 3942 | const char *buf, size_t count) |
| 3943 | { |
| 3944 | struct hstate *h, *demote_hstate; |
| 3945 | unsigned long demote_size; |
| 3946 | unsigned int demote_order; |
| 3947 | |
| 3948 | demote_size = (unsigned long)memparse(buf, NULL); |
| 3949 | |
| 3950 | demote_hstate = size_to_hstate(demote_size); |
| 3951 | if (!demote_hstate) |
| 3952 | return -EINVAL; |
| 3953 | demote_order = demote_hstate->order; |
| 3954 | if (demote_order < HUGETLB_PAGE_ORDER) |
| 3955 | return -EINVAL; |
| 3956 | |
| 3957 | /* demote order must be smaller than hstate order */ |
| 3958 | h = kobj_to_hstate(kobj, NULL); |
| 3959 | if (demote_order >= h->order) |
| 3960 | return -EINVAL; |
| 3961 | |
| 3962 | /* resize_lock synchronizes access to demote size and writes */ |
| 3963 | mutex_lock(&h->resize_lock); |
| 3964 | h->demote_order = demote_order; |
| 3965 | mutex_unlock(&h->resize_lock); |
| 3966 | |
| 3967 | return count; |
| 3968 | } |
| 3969 | HSTATE_ATTR(demote_size); |
| 3970 | |
| 3971 | static struct attribute *hstate_attrs[] = { |
| 3972 | &nr_hugepages_attr.attr, |
| 3973 | &nr_overcommit_hugepages_attr.attr, |
| 3974 | &free_hugepages_attr.attr, |
| 3975 | &resv_hugepages_attr.attr, |
| 3976 | &surplus_hugepages_attr.attr, |
| 3977 | #ifdef CONFIG_NUMA |
| 3978 | &nr_hugepages_mempolicy_attr.attr, |
| 3979 | #endif |
| 3980 | NULL, |
| 3981 | }; |
| 3982 | |
| 3983 | static const struct attribute_group hstate_attr_group = { |
| 3984 | .attrs = hstate_attrs, |
| 3985 | }; |
| 3986 | |
| 3987 | static struct attribute *hstate_demote_attrs[] = { |
| 3988 | &demote_size_attr.attr, |
| 3989 | &demote_attr.attr, |
| 3990 | NULL, |
| 3991 | }; |
| 3992 | |
| 3993 | static const struct attribute_group hstate_demote_attr_group = { |
| 3994 | .attrs = hstate_demote_attrs, |
| 3995 | }; |
| 3996 | |
| 3997 | static int hugetlb_sysfs_add_hstate(struct hstate *h, struct kobject *parent, |
| 3998 | struct kobject **hstate_kobjs, |
| 3999 | const struct attribute_group *hstate_attr_group) |
| 4000 | { |
| 4001 | int retval; |
| 4002 | int hi = hstate_index(h); |
| 4003 | |
| 4004 | hstate_kobjs[hi] = kobject_create_and_add(h->name, parent); |
| 4005 | if (!hstate_kobjs[hi]) |
| 4006 | return -ENOMEM; |
| 4007 | |
| 4008 | retval = sysfs_create_group(hstate_kobjs[hi], hstate_attr_group); |
| 4009 | if (retval) { |
| 4010 | kobject_put(hstate_kobjs[hi]); |
| 4011 | hstate_kobjs[hi] = NULL; |
| 4012 | return retval; |
| 4013 | } |
| 4014 | |
| 4015 | if (h->demote_order) { |
| 4016 | retval = sysfs_create_group(hstate_kobjs[hi], |
| 4017 | &hstate_demote_attr_group); |
| 4018 | if (retval) { |
| 4019 | pr_warn("HugeTLB unable to create demote interfaces for %s\n", h->name); |
| 4020 | sysfs_remove_group(hstate_kobjs[hi], hstate_attr_group); |
| 4021 | kobject_put(hstate_kobjs[hi]); |
| 4022 | hstate_kobjs[hi] = NULL; |
| 4023 | return retval; |
| 4024 | } |
| 4025 | } |
| 4026 | |
| 4027 | return 0; |
| 4028 | } |
| 4029 | |
| 4030 | #ifdef CONFIG_NUMA |
| 4031 | static bool hugetlb_sysfs_initialized __ro_after_init; |
| 4032 | |
| 4033 | /* |
| 4034 | * node_hstate/s - associate per node hstate attributes, via their kobjects, |
| 4035 | * with node devices in node_devices[] using a parallel array. The array |
| 4036 | * index of a node device or _hstate == node id. |
| 4037 | * This is here to avoid any static dependency of the node device driver, in |
| 4038 | * the base kernel, on the hugetlb module. |
| 4039 | */ |
| 4040 | struct node_hstate { |
| 4041 | struct kobject *hugepages_kobj; |
| 4042 | struct kobject *hstate_kobjs[HUGE_MAX_HSTATE]; |
| 4043 | }; |
| 4044 | static struct node_hstate node_hstates[MAX_NUMNODES]; |
| 4045 | |
| 4046 | /* |
| 4047 | * A subset of global hstate attributes for node devices |
| 4048 | */ |
| 4049 | static struct attribute *per_node_hstate_attrs[] = { |
| 4050 | &nr_hugepages_attr.attr, |
| 4051 | &free_hugepages_attr.attr, |
| 4052 | &surplus_hugepages_attr.attr, |
| 4053 | NULL, |
| 4054 | }; |
| 4055 | |
| 4056 | static const struct attribute_group per_node_hstate_attr_group = { |
| 4057 | .attrs = per_node_hstate_attrs, |
| 4058 | }; |
| 4059 | |
| 4060 | /* |
| 4061 | * kobj_to_node_hstate - lookup global hstate for node device hstate attr kobj. |
| 4062 | * Returns node id via non-NULL nidp. |
| 4063 | */ |
| 4064 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
| 4065 | { |
| 4066 | int nid; |
| 4067 | |
| 4068 | for (nid = 0; nid < nr_node_ids; nid++) { |
| 4069 | struct node_hstate *nhs = &node_hstates[nid]; |
| 4070 | int i; |
| 4071 | for (i = 0; i < HUGE_MAX_HSTATE; i++) |
| 4072 | if (nhs->hstate_kobjs[i] == kobj) { |
| 4073 | if (nidp) |
| 4074 | *nidp = nid; |
| 4075 | return &hstates[i]; |
| 4076 | } |
| 4077 | } |
| 4078 | |
| 4079 | BUG(); |
| 4080 | return NULL; |
| 4081 | } |
| 4082 | |
| 4083 | /* |
| 4084 | * Unregister hstate attributes from a single node device. |
| 4085 | * No-op if no hstate attributes attached. |
| 4086 | */ |
| 4087 | void hugetlb_unregister_node(struct node *node) |
| 4088 | { |
| 4089 | struct hstate *h; |
| 4090 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
| 4091 | |
| 4092 | if (!nhs->hugepages_kobj) |
| 4093 | return; /* no hstate attributes */ |
| 4094 | |
| 4095 | for_each_hstate(h) { |
| 4096 | int idx = hstate_index(h); |
| 4097 | struct kobject *hstate_kobj = nhs->hstate_kobjs[idx]; |
| 4098 | |
| 4099 | if (!hstate_kobj) |
| 4100 | continue; |
| 4101 | if (h->demote_order) |
| 4102 | sysfs_remove_group(hstate_kobj, &hstate_demote_attr_group); |
| 4103 | sysfs_remove_group(hstate_kobj, &per_node_hstate_attr_group); |
| 4104 | kobject_put(hstate_kobj); |
| 4105 | nhs->hstate_kobjs[idx] = NULL; |
| 4106 | } |
| 4107 | |
| 4108 | kobject_put(nhs->hugepages_kobj); |
| 4109 | nhs->hugepages_kobj = NULL; |
| 4110 | } |
| 4111 | |
| 4112 | |
| 4113 | /* |
| 4114 | * Register hstate attributes for a single node device. |
| 4115 | * No-op if attributes already registered. |
| 4116 | */ |
| 4117 | void hugetlb_register_node(struct node *node) |
| 4118 | { |
| 4119 | struct hstate *h; |
| 4120 | struct node_hstate *nhs = &node_hstates[node->dev.id]; |
| 4121 | int err; |
| 4122 | |
| 4123 | if (!hugetlb_sysfs_initialized) |
| 4124 | return; |
| 4125 | |
| 4126 | if (nhs->hugepages_kobj) |
| 4127 | return; /* already allocated */ |
| 4128 | |
| 4129 | nhs->hugepages_kobj = kobject_create_and_add("hugepages", |
| 4130 | &node->dev.kobj); |
| 4131 | if (!nhs->hugepages_kobj) |
| 4132 | return; |
| 4133 | |
| 4134 | for_each_hstate(h) { |
| 4135 | err = hugetlb_sysfs_add_hstate(h, nhs->hugepages_kobj, |
| 4136 | nhs->hstate_kobjs, |
| 4137 | &per_node_hstate_attr_group); |
| 4138 | if (err) { |
| 4139 | pr_err("HugeTLB: Unable to add hstate %s for node %d\n", |
| 4140 | h->name, node->dev.id); |
| 4141 | hugetlb_unregister_node(node); |
| 4142 | break; |
| 4143 | } |
| 4144 | } |
| 4145 | } |
| 4146 | |
| 4147 | /* |
| 4148 | * hugetlb init time: register hstate attributes for all registered node |
| 4149 | * devices of nodes that have memory. All on-line nodes should have |
| 4150 | * registered their associated device by this time. |
| 4151 | */ |
| 4152 | static void __init hugetlb_register_all_nodes(void) |
| 4153 | { |
| 4154 | int nid; |
| 4155 | |
| 4156 | for_each_online_node(nid) |
| 4157 | hugetlb_register_node(node_devices[nid]); |
| 4158 | } |
| 4159 | #else /* !CONFIG_NUMA */ |
| 4160 | |
| 4161 | static struct hstate *kobj_to_node_hstate(struct kobject *kobj, int *nidp) |
| 4162 | { |
| 4163 | BUG(); |
| 4164 | if (nidp) |
| 4165 | *nidp = -1; |
| 4166 | return NULL; |
| 4167 | } |
| 4168 | |
| 4169 | static void hugetlb_register_all_nodes(void) { } |
| 4170 | |
| 4171 | #endif |
| 4172 | |
| 4173 | #ifdef CONFIG_CMA |
| 4174 | static void __init hugetlb_cma_check(void); |
| 4175 | #else |
| 4176 | static inline __init void hugetlb_cma_check(void) |
| 4177 | { |
| 4178 | } |
| 4179 | #endif |
| 4180 | |
| 4181 | static void __init hugetlb_sysfs_init(void) |
| 4182 | { |
| 4183 | struct hstate *h; |
| 4184 | int err; |
| 4185 | |
| 4186 | hugepages_kobj = kobject_create_and_add("hugepages", mm_kobj); |
| 4187 | if (!hugepages_kobj) |
| 4188 | return; |
| 4189 | |
| 4190 | for_each_hstate(h) { |
| 4191 | err = hugetlb_sysfs_add_hstate(h, hugepages_kobj, |
| 4192 | hstate_kobjs, &hstate_attr_group); |
| 4193 | if (err) |
| 4194 | pr_err("HugeTLB: Unable to add hstate %s", h->name); |
| 4195 | } |
| 4196 | |
| 4197 | #ifdef CONFIG_NUMA |
| 4198 | hugetlb_sysfs_initialized = true; |
| 4199 | #endif |
| 4200 | hugetlb_register_all_nodes(); |
| 4201 | } |
| 4202 | |
| 4203 | static int __init hugetlb_init(void) |
| 4204 | { |
| 4205 | int i; |
| 4206 | |
| 4207 | BUILD_BUG_ON(sizeof_field(struct page, private) * BITS_PER_BYTE < |
| 4208 | __NR_HPAGEFLAGS); |
| 4209 | |
| 4210 | if (!hugepages_supported()) { |
| 4211 | if (hugetlb_max_hstate || default_hstate_max_huge_pages) |
| 4212 | pr_warn("HugeTLB: huge pages not supported, ignoring associated command-line parameters\n"); |
| 4213 | return 0; |
| 4214 | } |
| 4215 | |
| 4216 | /* |
| 4217 | * Make sure HPAGE_SIZE (HUGETLB_PAGE_ORDER) hstate exists. Some |
| 4218 | * architectures depend on setup being done here. |
| 4219 | */ |
| 4220 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
| 4221 | if (!parsed_default_hugepagesz) { |
| 4222 | /* |
| 4223 | * If we did not parse a default huge page size, set |
| 4224 | * default_hstate_idx to HPAGE_SIZE hstate. And, if the |
| 4225 | * number of huge pages for this default size was implicitly |
| 4226 | * specified, set that here as well. |
| 4227 | * Note that the implicit setting will overwrite an explicit |
| 4228 | * setting. A warning will be printed in this case. |
| 4229 | */ |
| 4230 | default_hstate_idx = hstate_index(size_to_hstate(HPAGE_SIZE)); |
| 4231 | if (default_hstate_max_huge_pages) { |
| 4232 | if (default_hstate.max_huge_pages) { |
| 4233 | char buf[32]; |
| 4234 | |
| 4235 | string_get_size(huge_page_size(&default_hstate), |
| 4236 | 1, STRING_UNITS_2, buf, 32); |
| 4237 | pr_warn("HugeTLB: Ignoring hugepages=%lu associated with %s page size\n", |
| 4238 | default_hstate.max_huge_pages, buf); |
| 4239 | pr_warn("HugeTLB: Using hugepages=%lu for number of default huge pages\n", |
| 4240 | default_hstate_max_huge_pages); |
| 4241 | } |
| 4242 | default_hstate.max_huge_pages = |
| 4243 | default_hstate_max_huge_pages; |
| 4244 | |
| 4245 | for_each_online_node(i) |
| 4246 | default_hstate.max_huge_pages_node[i] = |
| 4247 | default_hugepages_in_node[i]; |
| 4248 | } |
| 4249 | } |
| 4250 | |
| 4251 | hugetlb_cma_check(); |
| 4252 | hugetlb_init_hstates(); |
| 4253 | gather_bootmem_prealloc(); |
| 4254 | report_hugepages(); |
| 4255 | |
| 4256 | hugetlb_sysfs_init(); |
| 4257 | hugetlb_cgroup_file_init(); |
| 4258 | |
| 4259 | #ifdef CONFIG_SMP |
| 4260 | num_fault_mutexes = roundup_pow_of_two(8 * num_possible_cpus()); |
| 4261 | #else |
| 4262 | num_fault_mutexes = 1; |
| 4263 | #endif |
| 4264 | hugetlb_fault_mutex_table = |
| 4265 | kmalloc_array(num_fault_mutexes, sizeof(struct mutex), |
| 4266 | GFP_KERNEL); |
| 4267 | BUG_ON(!hugetlb_fault_mutex_table); |
| 4268 | |
| 4269 | for (i = 0; i < num_fault_mutexes; i++) |
| 4270 | mutex_init(&hugetlb_fault_mutex_table[i]); |
| 4271 | return 0; |
| 4272 | } |
| 4273 | subsys_initcall(hugetlb_init); |
| 4274 | |
| 4275 | /* Overwritten by architectures with more huge page sizes */ |
| 4276 | bool __init __attribute((weak)) arch_hugetlb_valid_size(unsigned long size) |
| 4277 | { |
| 4278 | return size == HPAGE_SIZE; |
| 4279 | } |
| 4280 | |
| 4281 | void __init hugetlb_add_hstate(unsigned int order) |
| 4282 | { |
| 4283 | struct hstate *h; |
| 4284 | unsigned long i; |
| 4285 | |
| 4286 | if (size_to_hstate(PAGE_SIZE << order)) { |
| 4287 | return; |
| 4288 | } |
| 4289 | BUG_ON(hugetlb_max_hstate >= HUGE_MAX_HSTATE); |
| 4290 | BUG_ON(order == 0); |
| 4291 | h = &hstates[hugetlb_max_hstate++]; |
| 4292 | mutex_init(&h->resize_lock); |
| 4293 | h->order = order; |
| 4294 | h->mask = ~(huge_page_size(h) - 1); |
| 4295 | for (i = 0; i < MAX_NUMNODES; ++i) |
| 4296 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
| 4297 | INIT_LIST_HEAD(&h->hugepage_activelist); |
| 4298 | h->next_nid_to_alloc = first_memory_node; |
| 4299 | h->next_nid_to_free = first_memory_node; |
| 4300 | snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB", |
| 4301 | huge_page_size(h)/SZ_1K); |
| 4302 | |
| 4303 | parsed_hstate = h; |
| 4304 | } |
| 4305 | |
| 4306 | bool __init __weak hugetlb_node_alloc_supported(void) |
| 4307 | { |
| 4308 | return true; |
| 4309 | } |
| 4310 | |
| 4311 | static void __init hugepages_clear_pages_in_node(void) |
| 4312 | { |
| 4313 | if (!hugetlb_max_hstate) { |
| 4314 | default_hstate_max_huge_pages = 0; |
| 4315 | memset(default_hugepages_in_node, 0, |
| 4316 | sizeof(default_hugepages_in_node)); |
| 4317 | } else { |
| 4318 | parsed_hstate->max_huge_pages = 0; |
| 4319 | memset(parsed_hstate->max_huge_pages_node, 0, |
| 4320 | sizeof(parsed_hstate->max_huge_pages_node)); |
| 4321 | } |
| 4322 | } |
| 4323 | |
| 4324 | /* |
| 4325 | * hugepages command line processing |
| 4326 | * hugepages normally follows a valid hugepagsz or default_hugepagsz |
| 4327 | * specification. If not, ignore the hugepages value. hugepages can also |
| 4328 | * be the first huge page command line option in which case it implicitly |
| 4329 | * specifies the number of huge pages for the default size. |
| 4330 | */ |
| 4331 | static int __init hugepages_setup(char *s) |
| 4332 | { |
| 4333 | unsigned long *mhp; |
| 4334 | static unsigned long *last_mhp; |
| 4335 | int node = NUMA_NO_NODE; |
| 4336 | int count; |
| 4337 | unsigned long tmp; |
| 4338 | char *p = s; |
| 4339 | |
| 4340 | if (!parsed_valid_hugepagesz) { |
| 4341 | pr_warn("HugeTLB: hugepages=%s does not follow a valid hugepagesz, ignoring\n", s); |
| 4342 | parsed_valid_hugepagesz = true; |
| 4343 | return 1; |
| 4344 | } |
| 4345 | |
| 4346 | /* |
| 4347 | * !hugetlb_max_hstate means we haven't parsed a hugepagesz= parameter |
| 4348 | * yet, so this hugepages= parameter goes to the "default hstate". |
| 4349 | * Otherwise, it goes with the previously parsed hugepagesz or |
| 4350 | * default_hugepagesz. |
| 4351 | */ |
| 4352 | else if (!hugetlb_max_hstate) |
| 4353 | mhp = &default_hstate_max_huge_pages; |
| 4354 | else |
| 4355 | mhp = &parsed_hstate->max_huge_pages; |
| 4356 | |
| 4357 | if (mhp == last_mhp) { |
| 4358 | pr_warn("HugeTLB: hugepages= specified twice without interleaving hugepagesz=, ignoring hugepages=%s\n", s); |
| 4359 | return 1; |
| 4360 | } |
| 4361 | |
| 4362 | while (*p) { |
| 4363 | count = 0; |
| 4364 | if (sscanf(p, "%lu%n", &tmp, &count) != 1) |
| 4365 | goto invalid; |
| 4366 | /* Parameter is node format */ |
| 4367 | if (p[count] == ':') { |
| 4368 | if (!hugetlb_node_alloc_supported()) { |
| 4369 | pr_warn("HugeTLB: architecture can't support node specific alloc, ignoring!\n"); |
| 4370 | return 1; |
| 4371 | } |
| 4372 | if (tmp >= MAX_NUMNODES || !node_online(tmp)) |
| 4373 | goto invalid; |
| 4374 | node = array_index_nospec(tmp, MAX_NUMNODES); |
| 4375 | p += count + 1; |
| 4376 | /* Parse hugepages */ |
| 4377 | if (sscanf(p, "%lu%n", &tmp, &count) != 1) |
| 4378 | goto invalid; |
| 4379 | if (!hugetlb_max_hstate) |
| 4380 | default_hugepages_in_node[node] = tmp; |
| 4381 | else |
| 4382 | parsed_hstate->max_huge_pages_node[node] = tmp; |
| 4383 | *mhp += tmp; |
| 4384 | /* Go to parse next node*/ |
| 4385 | if (p[count] == ',') |
| 4386 | p += count + 1; |
| 4387 | else |
| 4388 | break; |
| 4389 | } else { |
| 4390 | if (p != s) |
| 4391 | goto invalid; |
| 4392 | *mhp = tmp; |
| 4393 | break; |
| 4394 | } |
| 4395 | } |
| 4396 | |
| 4397 | /* |
| 4398 | * Global state is always initialized later in hugetlb_init. |
| 4399 | * But we need to allocate gigantic hstates here early to still |
| 4400 | * use the bootmem allocator. |
| 4401 | */ |
| 4402 | if (hugetlb_max_hstate && hstate_is_gigantic(parsed_hstate)) |
| 4403 | hugetlb_hstate_alloc_pages(parsed_hstate); |
| 4404 | |
| 4405 | last_mhp = mhp; |
| 4406 | |
| 4407 | return 1; |
| 4408 | |
| 4409 | invalid: |
| 4410 | pr_warn("HugeTLB: Invalid hugepages parameter %s\n", p); |
| 4411 | hugepages_clear_pages_in_node(); |
| 4412 | return 1; |
| 4413 | } |
| 4414 | __setup("hugepages=", hugepages_setup); |
| 4415 | |
| 4416 | /* |
| 4417 | * hugepagesz command line processing |
| 4418 | * A specific huge page size can only be specified once with hugepagesz. |
| 4419 | * hugepagesz is followed by hugepages on the command line. The global |
| 4420 | * variable 'parsed_valid_hugepagesz' is used to determine if prior |
| 4421 | * hugepagesz argument was valid. |
| 4422 | */ |
| 4423 | static int __init hugepagesz_setup(char *s) |
| 4424 | { |
| 4425 | unsigned long size; |
| 4426 | struct hstate *h; |
| 4427 | |
| 4428 | parsed_valid_hugepagesz = false; |
| 4429 | size = (unsigned long)memparse(s, NULL); |
| 4430 | |
| 4431 | if (!arch_hugetlb_valid_size(size)) { |
| 4432 | pr_err("HugeTLB: unsupported hugepagesz=%s\n", s); |
| 4433 | return 1; |
| 4434 | } |
| 4435 | |
| 4436 | h = size_to_hstate(size); |
| 4437 | if (h) { |
| 4438 | /* |
| 4439 | * hstate for this size already exists. This is normally |
| 4440 | * an error, but is allowed if the existing hstate is the |
| 4441 | * default hstate. More specifically, it is only allowed if |
| 4442 | * the number of huge pages for the default hstate was not |
| 4443 | * previously specified. |
| 4444 | */ |
| 4445 | if (!parsed_default_hugepagesz || h != &default_hstate || |
| 4446 | default_hstate.max_huge_pages) { |
| 4447 | pr_warn("HugeTLB: hugepagesz=%s specified twice, ignoring\n", s); |
| 4448 | return 1; |
| 4449 | } |
| 4450 | |
| 4451 | /* |
| 4452 | * No need to call hugetlb_add_hstate() as hstate already |
| 4453 | * exists. But, do set parsed_hstate so that a following |
| 4454 | * hugepages= parameter will be applied to this hstate. |
| 4455 | */ |
| 4456 | parsed_hstate = h; |
| 4457 | parsed_valid_hugepagesz = true; |
| 4458 | return 1; |
| 4459 | } |
| 4460 | |
| 4461 | hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT); |
| 4462 | parsed_valid_hugepagesz = true; |
| 4463 | return 1; |
| 4464 | } |
| 4465 | __setup("hugepagesz=", hugepagesz_setup); |
| 4466 | |
| 4467 | /* |
| 4468 | * default_hugepagesz command line input |
| 4469 | * Only one instance of default_hugepagesz allowed on command line. |
| 4470 | */ |
| 4471 | static int __init default_hugepagesz_setup(char *s) |
| 4472 | { |
| 4473 | unsigned long size; |
| 4474 | int i; |
| 4475 | |
| 4476 | parsed_valid_hugepagesz = false; |
| 4477 | if (parsed_default_hugepagesz) { |
| 4478 | pr_err("HugeTLB: default_hugepagesz previously specified, ignoring %s\n", s); |
| 4479 | return 1; |
| 4480 | } |
| 4481 | |
| 4482 | size = (unsigned long)memparse(s, NULL); |
| 4483 | |
| 4484 | if (!arch_hugetlb_valid_size(size)) { |
| 4485 | pr_err("HugeTLB: unsupported default_hugepagesz=%s\n", s); |
| 4486 | return 1; |
| 4487 | } |
| 4488 | |
| 4489 | hugetlb_add_hstate(ilog2(size) - PAGE_SHIFT); |
| 4490 | parsed_valid_hugepagesz = true; |
| 4491 | parsed_default_hugepagesz = true; |
| 4492 | default_hstate_idx = hstate_index(size_to_hstate(size)); |
| 4493 | |
| 4494 | /* |
| 4495 | * The number of default huge pages (for this size) could have been |
| 4496 | * specified as the first hugetlb parameter: hugepages=X. If so, |
| 4497 | * then default_hstate_max_huge_pages is set. If the default huge |
| 4498 | * page size is gigantic (>= MAX_ORDER), then the pages must be |
| 4499 | * allocated here from bootmem allocator. |
| 4500 | */ |
| 4501 | if (default_hstate_max_huge_pages) { |
| 4502 | default_hstate.max_huge_pages = default_hstate_max_huge_pages; |
| 4503 | for_each_online_node(i) |
| 4504 | default_hstate.max_huge_pages_node[i] = |
| 4505 | default_hugepages_in_node[i]; |
| 4506 | if (hstate_is_gigantic(&default_hstate)) |
| 4507 | hugetlb_hstate_alloc_pages(&default_hstate); |
| 4508 | default_hstate_max_huge_pages = 0; |
| 4509 | } |
| 4510 | |
| 4511 | return 1; |
| 4512 | } |
| 4513 | __setup("default_hugepagesz=", default_hugepagesz_setup); |
| 4514 | |
| 4515 | static nodemask_t *policy_mbind_nodemask(gfp_t gfp) |
| 4516 | { |
| 4517 | #ifdef CONFIG_NUMA |
| 4518 | struct mempolicy *mpol = get_task_policy(current); |
| 4519 | |
| 4520 | /* |
| 4521 | * Only enforce MPOL_BIND policy which overlaps with cpuset policy |
| 4522 | * (from policy_nodemask) specifically for hugetlb case |
| 4523 | */ |
| 4524 | if (mpol->mode == MPOL_BIND && |
| 4525 | (apply_policy_zone(mpol, gfp_zone(gfp)) && |
| 4526 | cpuset_nodemask_valid_mems_allowed(&mpol->nodes))) |
| 4527 | return &mpol->nodes; |
| 4528 | #endif |
| 4529 | return NULL; |
| 4530 | } |
| 4531 | |
| 4532 | static unsigned int allowed_mems_nr(struct hstate *h) |
| 4533 | { |
| 4534 | int node; |
| 4535 | unsigned int nr = 0; |
| 4536 | nodemask_t *mbind_nodemask; |
| 4537 | unsigned int *array = h->free_huge_pages_node; |
| 4538 | gfp_t gfp_mask = htlb_alloc_mask(h); |
| 4539 | |
| 4540 | mbind_nodemask = policy_mbind_nodemask(gfp_mask); |
| 4541 | for_each_node_mask(node, cpuset_current_mems_allowed) { |
| 4542 | if (!mbind_nodemask || node_isset(node, *mbind_nodemask)) |
| 4543 | nr += array[node]; |
| 4544 | } |
| 4545 | |
| 4546 | return nr; |
| 4547 | } |
| 4548 | |
| 4549 | #ifdef CONFIG_SYSCTL |
| 4550 | static int proc_hugetlb_doulongvec_minmax(struct ctl_table *table, int write, |
| 4551 | void *buffer, size_t *length, |
| 4552 | loff_t *ppos, unsigned long *out) |
| 4553 | { |
| 4554 | struct ctl_table dup_table; |
| 4555 | |
| 4556 | /* |
| 4557 | * In order to avoid races with __do_proc_doulongvec_minmax(), we |
| 4558 | * can duplicate the @table and alter the duplicate of it. |
| 4559 | */ |
| 4560 | dup_table = *table; |
| 4561 | dup_table.data = out; |
| 4562 | |
| 4563 | return proc_doulongvec_minmax(&dup_table, write, buffer, length, ppos); |
| 4564 | } |
| 4565 | |
| 4566 | static int hugetlb_sysctl_handler_common(bool obey_mempolicy, |
| 4567 | struct ctl_table *table, int write, |
| 4568 | void *buffer, size_t *length, loff_t *ppos) |
| 4569 | { |
| 4570 | struct hstate *h = &default_hstate; |
| 4571 | unsigned long tmp = h->max_huge_pages; |
| 4572 | int ret; |
| 4573 | |
| 4574 | if (!hugepages_supported()) |
| 4575 | return -EOPNOTSUPP; |
| 4576 | |
| 4577 | ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos, |
| 4578 | &tmp); |
| 4579 | if (ret) |
| 4580 | goto out; |
| 4581 | |
| 4582 | if (write) |
| 4583 | ret = __nr_hugepages_store_common(obey_mempolicy, h, |
| 4584 | NUMA_NO_NODE, tmp, *length); |
| 4585 | out: |
| 4586 | return ret; |
| 4587 | } |
| 4588 | |
| 4589 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
| 4590 | void *buffer, size_t *length, loff_t *ppos) |
| 4591 | { |
| 4592 | |
| 4593 | return hugetlb_sysctl_handler_common(false, table, write, |
| 4594 | buffer, length, ppos); |
| 4595 | } |
| 4596 | |
| 4597 | #ifdef CONFIG_NUMA |
| 4598 | int hugetlb_mempolicy_sysctl_handler(struct ctl_table *table, int write, |
| 4599 | void *buffer, size_t *length, loff_t *ppos) |
| 4600 | { |
| 4601 | return hugetlb_sysctl_handler_common(true, table, write, |
| 4602 | buffer, length, ppos); |
| 4603 | } |
| 4604 | #endif /* CONFIG_NUMA */ |
| 4605 | |
| 4606 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
| 4607 | void *buffer, size_t *length, loff_t *ppos) |
| 4608 | { |
| 4609 | struct hstate *h = &default_hstate; |
| 4610 | unsigned long tmp; |
| 4611 | int ret; |
| 4612 | |
| 4613 | if (!hugepages_supported()) |
| 4614 | return -EOPNOTSUPP; |
| 4615 | |
| 4616 | tmp = h->nr_overcommit_huge_pages; |
| 4617 | |
| 4618 | if (write && hstate_is_gigantic(h)) |
| 4619 | return -EINVAL; |
| 4620 | |
| 4621 | ret = proc_hugetlb_doulongvec_minmax(table, write, buffer, length, ppos, |
| 4622 | &tmp); |
| 4623 | if (ret) |
| 4624 | goto out; |
| 4625 | |
| 4626 | if (write) { |
| 4627 | spin_lock_irq(&hugetlb_lock); |
| 4628 | h->nr_overcommit_huge_pages = tmp; |
| 4629 | spin_unlock_irq(&hugetlb_lock); |
| 4630 | } |
| 4631 | out: |
| 4632 | return ret; |
| 4633 | } |
| 4634 | |
| 4635 | #endif /* CONFIG_SYSCTL */ |
| 4636 | |
| 4637 | void hugetlb_report_meminfo(struct seq_file *m) |
| 4638 | { |
| 4639 | struct hstate *h; |
| 4640 | unsigned long total = 0; |
| 4641 | |
| 4642 | if (!hugepages_supported()) |
| 4643 | return; |
| 4644 | |
| 4645 | for_each_hstate(h) { |
| 4646 | unsigned long count = h->nr_huge_pages; |
| 4647 | |
| 4648 | total += huge_page_size(h) * count; |
| 4649 | |
| 4650 | if (h == &default_hstate) |
| 4651 | seq_printf(m, |
| 4652 | "HugePages_Total: %5lu\n" |
| 4653 | "HugePages_Free: %5lu\n" |
| 4654 | "HugePages_Rsvd: %5lu\n" |
| 4655 | "HugePages_Surp: %5lu\n" |
| 4656 | "Hugepagesize: %8lu kB\n", |
| 4657 | count, |
| 4658 | h->free_huge_pages, |
| 4659 | h->resv_huge_pages, |
| 4660 | h->surplus_huge_pages, |
| 4661 | huge_page_size(h) / SZ_1K); |
| 4662 | } |
| 4663 | |
| 4664 | seq_printf(m, "Hugetlb: %8lu kB\n", total / SZ_1K); |
| 4665 | } |
| 4666 | |
| 4667 | int hugetlb_report_node_meminfo(char *buf, int len, int nid) |
| 4668 | { |
| 4669 | struct hstate *h = &default_hstate; |
| 4670 | |
| 4671 | if (!hugepages_supported()) |
| 4672 | return 0; |
| 4673 | |
| 4674 | return sysfs_emit_at(buf, len, |
| 4675 | "Node %d HugePages_Total: %5u\n" |
| 4676 | "Node %d HugePages_Free: %5u\n" |
| 4677 | "Node %d HugePages_Surp: %5u\n", |
| 4678 | nid, h->nr_huge_pages_node[nid], |
| 4679 | nid, h->free_huge_pages_node[nid], |
| 4680 | nid, h->surplus_huge_pages_node[nid]); |
| 4681 | } |
| 4682 | |
| 4683 | void hugetlb_show_meminfo_node(int nid) |
| 4684 | { |
| 4685 | struct hstate *h; |
| 4686 | |
| 4687 | if (!hugepages_supported()) |
| 4688 | return; |
| 4689 | |
| 4690 | for_each_hstate(h) |
| 4691 | printk("Node %d hugepages_total=%u hugepages_free=%u hugepages_surp=%u hugepages_size=%lukB\n", |
| 4692 | nid, |
| 4693 | h->nr_huge_pages_node[nid], |
| 4694 | h->free_huge_pages_node[nid], |
| 4695 | h->surplus_huge_pages_node[nid], |
| 4696 | huge_page_size(h) / SZ_1K); |
| 4697 | } |
| 4698 | |
| 4699 | void hugetlb_report_usage(struct seq_file *m, struct mm_struct *mm) |
| 4700 | { |
| 4701 | seq_printf(m, "HugetlbPages:\t%8lu kB\n", |
| 4702 | atomic_long_read(&mm->hugetlb_usage) << (PAGE_SHIFT - 10)); |
| 4703 | } |
| 4704 | |
| 4705 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
| 4706 | unsigned long hugetlb_total_pages(void) |
| 4707 | { |
| 4708 | struct hstate *h; |
| 4709 | unsigned long nr_total_pages = 0; |
| 4710 | |
| 4711 | for_each_hstate(h) |
| 4712 | nr_total_pages += h->nr_huge_pages * pages_per_huge_page(h); |
| 4713 | return nr_total_pages; |
| 4714 | } |
| 4715 | |
| 4716 | static int hugetlb_acct_memory(struct hstate *h, long delta) |
| 4717 | { |
| 4718 | int ret = -ENOMEM; |
| 4719 | |
| 4720 | if (!delta) |
| 4721 | return 0; |
| 4722 | |
| 4723 | spin_lock_irq(&hugetlb_lock); |
| 4724 | /* |
| 4725 | * When cpuset is configured, it breaks the strict hugetlb page |
| 4726 | * reservation as the accounting is done on a global variable. Such |
| 4727 | * reservation is completely rubbish in the presence of cpuset because |
| 4728 | * the reservation is not checked against page availability for the |
| 4729 | * current cpuset. Application can still potentially OOM'ed by kernel |
| 4730 | * with lack of free htlb page in cpuset that the task is in. |
| 4731 | * Attempt to enforce strict accounting with cpuset is almost |
| 4732 | * impossible (or too ugly) because cpuset is too fluid that |
| 4733 | * task or memory node can be dynamically moved between cpusets. |
| 4734 | * |
| 4735 | * The change of semantics for shared hugetlb mapping with cpuset is |
| 4736 | * undesirable. However, in order to preserve some of the semantics, |
| 4737 | * we fall back to check against current free page availability as |
| 4738 | * a best attempt and hopefully to minimize the impact of changing |
| 4739 | * semantics that cpuset has. |
| 4740 | * |
| 4741 | * Apart from cpuset, we also have memory policy mechanism that |
| 4742 | * also determines from which node the kernel will allocate memory |
| 4743 | * in a NUMA system. So similar to cpuset, we also should consider |
| 4744 | * the memory policy of the current task. Similar to the description |
| 4745 | * above. |
| 4746 | */ |
| 4747 | if (delta > 0) { |
| 4748 | if (gather_surplus_pages(h, delta) < 0) |
| 4749 | goto out; |
| 4750 | |
| 4751 | if (delta > allowed_mems_nr(h)) { |
| 4752 | return_unused_surplus_pages(h, delta); |
| 4753 | goto out; |
| 4754 | } |
| 4755 | } |
| 4756 | |
| 4757 | ret = 0; |
| 4758 | if (delta < 0) |
| 4759 | return_unused_surplus_pages(h, (unsigned long) -delta); |
| 4760 | |
| 4761 | out: |
| 4762 | spin_unlock_irq(&hugetlb_lock); |
| 4763 | return ret; |
| 4764 | } |
| 4765 | |
| 4766 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
| 4767 | { |
| 4768 | struct resv_map *resv = vma_resv_map(vma); |
| 4769 | |
| 4770 | /* |
| 4771 | * HPAGE_RESV_OWNER indicates a private mapping. |
| 4772 | * This new VMA should share its siblings reservation map if present. |
| 4773 | * The VMA will only ever have a valid reservation map pointer where |
| 4774 | * it is being copied for another still existing VMA. As that VMA |
| 4775 | * has a reference to the reservation map it cannot disappear until |
| 4776 | * after this open call completes. It is therefore safe to take a |
| 4777 | * new reference here without additional locking. |
| 4778 | */ |
| 4779 | if (resv && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| 4780 | resv_map_dup_hugetlb_cgroup_uncharge_info(resv); |
| 4781 | kref_get(&resv->refs); |
| 4782 | } |
| 4783 | |
| 4784 | /* |
| 4785 | * vma_lock structure for sharable mappings is vma specific. |
| 4786 | * Clear old pointer (if copied via vm_area_dup) and allocate |
| 4787 | * new structure. Before clearing, make sure vma_lock is not |
| 4788 | * for this vma. |
| 4789 | */ |
| 4790 | if (vma->vm_flags & VM_MAYSHARE) { |
| 4791 | struct hugetlb_vma_lock *vma_lock = vma->vm_private_data; |
| 4792 | |
| 4793 | if (vma_lock) { |
| 4794 | if (vma_lock->vma != vma) { |
| 4795 | vma->vm_private_data = NULL; |
| 4796 | hugetlb_vma_lock_alloc(vma); |
| 4797 | } else |
| 4798 | pr_warn("HugeTLB: vma_lock already exists in %s.\n", __func__); |
| 4799 | } else |
| 4800 | hugetlb_vma_lock_alloc(vma); |
| 4801 | } |
| 4802 | } |
| 4803 | |
| 4804 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
| 4805 | { |
| 4806 | struct hstate *h = hstate_vma(vma); |
| 4807 | struct resv_map *resv; |
| 4808 | struct hugepage_subpool *spool = subpool_vma(vma); |
| 4809 | unsigned long reserve, start, end; |
| 4810 | long gbl_reserve; |
| 4811 | |
| 4812 | hugetlb_vma_lock_free(vma); |
| 4813 | |
| 4814 | resv = vma_resv_map(vma); |
| 4815 | if (!resv || !is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| 4816 | return; |
| 4817 | |
| 4818 | start = vma_hugecache_offset(h, vma, vma->vm_start); |
| 4819 | end = vma_hugecache_offset(h, vma, vma->vm_end); |
| 4820 | |
| 4821 | reserve = (end - start) - region_count(resv, start, end); |
| 4822 | hugetlb_cgroup_uncharge_counter(resv, start, end); |
| 4823 | if (reserve) { |
| 4824 | /* |
| 4825 | * Decrement reserve counts. The global reserve count may be |
| 4826 | * adjusted if the subpool has a minimum size. |
| 4827 | */ |
| 4828 | gbl_reserve = hugepage_subpool_put_pages(spool, reserve); |
| 4829 | hugetlb_acct_memory(h, -gbl_reserve); |
| 4830 | } |
| 4831 | |
| 4832 | kref_put(&resv->refs, resv_map_release); |
| 4833 | } |
| 4834 | |
| 4835 | static int hugetlb_vm_op_split(struct vm_area_struct *vma, unsigned long addr) |
| 4836 | { |
| 4837 | if (addr & ~(huge_page_mask(hstate_vma(vma)))) |
| 4838 | return -EINVAL; |
| 4839 | |
| 4840 | /* |
| 4841 | * PMD sharing is only possible for PUD_SIZE-aligned address ranges |
| 4842 | * in HugeTLB VMAs. If we will lose PUD_SIZE alignment due to this |
| 4843 | * split, unshare PMDs in the PUD_SIZE interval surrounding addr now. |
| 4844 | */ |
| 4845 | if (addr & ~PUD_MASK) { |
| 4846 | /* |
| 4847 | * hugetlb_vm_op_split is called right before we attempt to |
| 4848 | * split the VMA. We will need to unshare PMDs in the old and |
| 4849 | * new VMAs, so let's unshare before we split. |
| 4850 | */ |
| 4851 | unsigned long floor = addr & PUD_MASK; |
| 4852 | unsigned long ceil = floor + PUD_SIZE; |
| 4853 | |
| 4854 | if (floor >= vma->vm_start && ceil <= vma->vm_end) |
| 4855 | hugetlb_unshare_pmds(vma, floor, ceil); |
| 4856 | } |
| 4857 | |
| 4858 | return 0; |
| 4859 | } |
| 4860 | |
| 4861 | static unsigned long hugetlb_vm_op_pagesize(struct vm_area_struct *vma) |
| 4862 | { |
| 4863 | return huge_page_size(hstate_vma(vma)); |
| 4864 | } |
| 4865 | |
| 4866 | /* |
| 4867 | * We cannot handle pagefaults against hugetlb pages at all. They cause |
| 4868 | * handle_mm_fault() to try to instantiate regular-sized pages in the |
| 4869 | * hugepage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
| 4870 | * this far. |
| 4871 | */ |
| 4872 | static vm_fault_t hugetlb_vm_op_fault(struct vm_fault *vmf) |
| 4873 | { |
| 4874 | BUG(); |
| 4875 | return 0; |
| 4876 | } |
| 4877 | |
| 4878 | /* |
| 4879 | * When a new function is introduced to vm_operations_struct and added |
| 4880 | * to hugetlb_vm_ops, please consider adding the function to shm_vm_ops. |
| 4881 | * This is because under System V memory model, mappings created via |
| 4882 | * shmget/shmat with "huge page" specified are backed by hugetlbfs files, |
| 4883 | * their original vm_ops are overwritten with shm_vm_ops. |
| 4884 | */ |
| 4885 | const struct vm_operations_struct hugetlb_vm_ops = { |
| 4886 | .fault = hugetlb_vm_op_fault, |
| 4887 | .open = hugetlb_vm_op_open, |
| 4888 | .close = hugetlb_vm_op_close, |
| 4889 | .may_split = hugetlb_vm_op_split, |
| 4890 | .pagesize = hugetlb_vm_op_pagesize, |
| 4891 | }; |
| 4892 | |
| 4893 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
| 4894 | int writable) |
| 4895 | { |
| 4896 | pte_t entry; |
| 4897 | unsigned int shift = huge_page_shift(hstate_vma(vma)); |
| 4898 | |
| 4899 | if (writable) { |
| 4900 | entry = huge_pte_mkwrite(huge_pte_mkdirty(mk_huge_pte(page, |
| 4901 | vma->vm_page_prot))); |
| 4902 | } else { |
| 4903 | entry = huge_pte_wrprotect(mk_huge_pte(page, |
| 4904 | vma->vm_page_prot)); |
| 4905 | } |
| 4906 | entry = pte_mkyoung(entry); |
| 4907 | entry = arch_make_huge_pte(entry, shift, vma->vm_flags); |
| 4908 | |
| 4909 | return entry; |
| 4910 | } |
| 4911 | |
| 4912 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
| 4913 | unsigned long address, pte_t *ptep) |
| 4914 | { |
| 4915 | pte_t entry; |
| 4916 | |
| 4917 | entry = huge_pte_mkwrite(huge_pte_mkdirty(huge_ptep_get(ptep))); |
| 4918 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) |
| 4919 | update_mmu_cache(vma, address, ptep); |
| 4920 | } |
| 4921 | |
| 4922 | bool is_hugetlb_entry_migration(pte_t pte) |
| 4923 | { |
| 4924 | swp_entry_t swp; |
| 4925 | |
| 4926 | if (huge_pte_none(pte) || pte_present(pte)) |
| 4927 | return false; |
| 4928 | swp = pte_to_swp_entry(pte); |
| 4929 | if (is_migration_entry(swp)) |
| 4930 | return true; |
| 4931 | else |
| 4932 | return false; |
| 4933 | } |
| 4934 | |
| 4935 | static bool is_hugetlb_entry_hwpoisoned(pte_t pte) |
| 4936 | { |
| 4937 | swp_entry_t swp; |
| 4938 | |
| 4939 | if (huge_pte_none(pte) || pte_present(pte)) |
| 4940 | return false; |
| 4941 | swp = pte_to_swp_entry(pte); |
| 4942 | if (is_hwpoison_entry(swp)) |
| 4943 | return true; |
| 4944 | else |
| 4945 | return false; |
| 4946 | } |
| 4947 | |
| 4948 | static void |
| 4949 | hugetlb_install_page(struct vm_area_struct *vma, pte_t *ptep, unsigned long addr, |
| 4950 | struct page *new_page) |
| 4951 | { |
| 4952 | __SetPageUptodate(new_page); |
| 4953 | hugepage_add_new_anon_rmap(new_page, vma, addr); |
| 4954 | set_huge_pte_at(vma->vm_mm, addr, ptep, make_huge_pte(vma, new_page, 1)); |
| 4955 | hugetlb_count_add(pages_per_huge_page(hstate_vma(vma)), vma->vm_mm); |
| 4956 | SetHPageMigratable(new_page); |
| 4957 | } |
| 4958 | |
| 4959 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
| 4960 | struct vm_area_struct *dst_vma, |
| 4961 | struct vm_area_struct *src_vma) |
| 4962 | { |
| 4963 | pte_t *src_pte, *dst_pte, entry; |
| 4964 | struct page *ptepage; |
| 4965 | unsigned long addr; |
| 4966 | bool cow = is_cow_mapping(src_vma->vm_flags); |
| 4967 | struct hstate *h = hstate_vma(src_vma); |
| 4968 | unsigned long sz = huge_page_size(h); |
| 4969 | unsigned long npages = pages_per_huge_page(h); |
| 4970 | struct mmu_notifier_range range; |
| 4971 | unsigned long last_addr_mask; |
| 4972 | int ret = 0; |
| 4973 | |
| 4974 | if (cow) { |
| 4975 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, src_vma, src, |
| 4976 | src_vma->vm_start, |
| 4977 | src_vma->vm_end); |
| 4978 | mmu_notifier_invalidate_range_start(&range); |
| 4979 | mmap_assert_write_locked(src); |
| 4980 | raw_write_seqcount_begin(&src->write_protect_seq); |
| 4981 | } else { |
| 4982 | /* |
| 4983 | * For shared mappings the vma lock must be held before |
| 4984 | * calling huge_pte_offset in the src vma. Otherwise, the |
| 4985 | * returned ptep could go away if part of a shared pmd and |
| 4986 | * another thread calls huge_pmd_unshare. |
| 4987 | */ |
| 4988 | hugetlb_vma_lock_read(src_vma); |
| 4989 | } |
| 4990 | |
| 4991 | last_addr_mask = hugetlb_mask_last_page(h); |
| 4992 | for (addr = src_vma->vm_start; addr < src_vma->vm_end; addr += sz) { |
| 4993 | spinlock_t *src_ptl, *dst_ptl; |
| 4994 | src_pte = huge_pte_offset(src, addr, sz); |
| 4995 | if (!src_pte) { |
| 4996 | addr |= last_addr_mask; |
| 4997 | continue; |
| 4998 | } |
| 4999 | dst_pte = huge_pte_alloc(dst, dst_vma, addr, sz); |
| 5000 | if (!dst_pte) { |
| 5001 | ret = -ENOMEM; |
| 5002 | break; |
| 5003 | } |
| 5004 | |
| 5005 | /* |
| 5006 | * If the pagetables are shared don't copy or take references. |
| 5007 | * |
| 5008 | * dst_pte == src_pte is the common case of src/dest sharing. |
| 5009 | * However, src could have 'unshared' and dst shares with |
| 5010 | * another vma. So page_count of ptep page is checked instead |
| 5011 | * to reliably determine whether pte is shared. |
| 5012 | */ |
| 5013 | if (page_count(virt_to_page(dst_pte)) > 1) { |
| 5014 | addr |= last_addr_mask; |
| 5015 | continue; |
| 5016 | } |
| 5017 | |
| 5018 | dst_ptl = huge_pte_lock(h, dst, dst_pte); |
| 5019 | src_ptl = huge_pte_lockptr(h, src, src_pte); |
| 5020 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
| 5021 | entry = huge_ptep_get(src_pte); |
| 5022 | again: |
| 5023 | if (huge_pte_none(entry)) { |
| 5024 | /* |
| 5025 | * Skip if src entry none. |
| 5026 | */ |
| 5027 | ; |
| 5028 | } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) { |
| 5029 | bool uffd_wp = huge_pte_uffd_wp(entry); |
| 5030 | |
| 5031 | if (!userfaultfd_wp(dst_vma) && uffd_wp) |
| 5032 | entry = huge_pte_clear_uffd_wp(entry); |
| 5033 | set_huge_pte_at(dst, addr, dst_pte, entry); |
| 5034 | } else if (unlikely(is_hugetlb_entry_migration(entry))) { |
| 5035 | swp_entry_t swp_entry = pte_to_swp_entry(entry); |
| 5036 | bool uffd_wp = huge_pte_uffd_wp(entry); |
| 5037 | |
| 5038 | if (!is_readable_migration_entry(swp_entry) && cow) { |
| 5039 | /* |
| 5040 | * COW mappings require pages in both |
| 5041 | * parent and child to be set to read. |
| 5042 | */ |
| 5043 | swp_entry = make_readable_migration_entry( |
| 5044 | swp_offset(swp_entry)); |
| 5045 | entry = swp_entry_to_pte(swp_entry); |
| 5046 | if (userfaultfd_wp(src_vma) && uffd_wp) |
| 5047 | entry = huge_pte_mkuffd_wp(entry); |
| 5048 | set_huge_pte_at(src, addr, src_pte, entry); |
| 5049 | } |
| 5050 | if (!userfaultfd_wp(dst_vma) && uffd_wp) |
| 5051 | entry = huge_pte_clear_uffd_wp(entry); |
| 5052 | set_huge_pte_at(dst, addr, dst_pte, entry); |
| 5053 | } else if (unlikely(is_pte_marker(entry))) { |
| 5054 | /* |
| 5055 | * We copy the pte marker only if the dst vma has |
| 5056 | * uffd-wp enabled. |
| 5057 | */ |
| 5058 | if (userfaultfd_wp(dst_vma)) |
| 5059 | set_huge_pte_at(dst, addr, dst_pte, entry); |
| 5060 | } else { |
| 5061 | entry = huge_ptep_get(src_pte); |
| 5062 | ptepage = pte_page(entry); |
| 5063 | get_page(ptepage); |
| 5064 | |
| 5065 | /* |
| 5066 | * Failing to duplicate the anon rmap is a rare case |
| 5067 | * where we see pinned hugetlb pages while they're |
| 5068 | * prone to COW. We need to do the COW earlier during |
| 5069 | * fork. |
| 5070 | * |
| 5071 | * When pre-allocating the page or copying data, we |
| 5072 | * need to be without the pgtable locks since we could |
| 5073 | * sleep during the process. |
| 5074 | */ |
| 5075 | if (!PageAnon(ptepage)) { |
| 5076 | page_dup_file_rmap(ptepage, true); |
| 5077 | } else if (page_try_dup_anon_rmap(ptepage, true, |
| 5078 | src_vma)) { |
| 5079 | pte_t src_pte_old = entry; |
| 5080 | struct page *new; |
| 5081 | |
| 5082 | spin_unlock(src_ptl); |
| 5083 | spin_unlock(dst_ptl); |
| 5084 | /* Do not use reserve as it's private owned */ |
| 5085 | new = alloc_huge_page(dst_vma, addr, 1); |
| 5086 | if (IS_ERR(new)) { |
| 5087 | put_page(ptepage); |
| 5088 | ret = PTR_ERR(new); |
| 5089 | break; |
| 5090 | } |
| 5091 | copy_user_huge_page(new, ptepage, addr, dst_vma, |
| 5092 | npages); |
| 5093 | put_page(ptepage); |
| 5094 | |
| 5095 | /* Install the new huge page if src pte stable */ |
| 5096 | dst_ptl = huge_pte_lock(h, dst, dst_pte); |
| 5097 | src_ptl = huge_pte_lockptr(h, src, src_pte); |
| 5098 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
| 5099 | entry = huge_ptep_get(src_pte); |
| 5100 | if (!pte_same(src_pte_old, entry)) { |
| 5101 | restore_reserve_on_error(h, dst_vma, addr, |
| 5102 | new); |
| 5103 | put_page(new); |
| 5104 | /* huge_ptep of dst_pte won't change as in child */ |
| 5105 | goto again; |
| 5106 | } |
| 5107 | hugetlb_install_page(dst_vma, dst_pte, addr, new); |
| 5108 | spin_unlock(src_ptl); |
| 5109 | spin_unlock(dst_ptl); |
| 5110 | continue; |
| 5111 | } |
| 5112 | |
| 5113 | if (cow) { |
| 5114 | /* |
| 5115 | * No need to notify as we are downgrading page |
| 5116 | * table protection not changing it to point |
| 5117 | * to a new page. |
| 5118 | * |
| 5119 | * See Documentation/mm/mmu_notifier.rst |
| 5120 | */ |
| 5121 | huge_ptep_set_wrprotect(src, addr, src_pte); |
| 5122 | entry = huge_pte_wrprotect(entry); |
| 5123 | } |
| 5124 | |
| 5125 | set_huge_pte_at(dst, addr, dst_pte, entry); |
| 5126 | hugetlb_count_add(npages, dst); |
| 5127 | } |
| 5128 | spin_unlock(src_ptl); |
| 5129 | spin_unlock(dst_ptl); |
| 5130 | } |
| 5131 | |
| 5132 | if (cow) { |
| 5133 | raw_write_seqcount_end(&src->write_protect_seq); |
| 5134 | mmu_notifier_invalidate_range_end(&range); |
| 5135 | } else { |
| 5136 | hugetlb_vma_unlock_read(src_vma); |
| 5137 | } |
| 5138 | |
| 5139 | return ret; |
| 5140 | } |
| 5141 | |
| 5142 | static void move_huge_pte(struct vm_area_struct *vma, unsigned long old_addr, |
| 5143 | unsigned long new_addr, pte_t *src_pte, pte_t *dst_pte) |
| 5144 | { |
| 5145 | struct hstate *h = hstate_vma(vma); |
| 5146 | struct mm_struct *mm = vma->vm_mm; |
| 5147 | spinlock_t *src_ptl, *dst_ptl; |
| 5148 | pte_t pte; |
| 5149 | |
| 5150 | dst_ptl = huge_pte_lock(h, mm, dst_pte); |
| 5151 | src_ptl = huge_pte_lockptr(h, mm, src_pte); |
| 5152 | |
| 5153 | /* |
| 5154 | * We don't have to worry about the ordering of src and dst ptlocks |
| 5155 | * because exclusive mmap_lock (or the i_mmap_lock) prevents deadlock. |
| 5156 | */ |
| 5157 | if (src_ptl != dst_ptl) |
| 5158 | spin_lock_nested(src_ptl, SINGLE_DEPTH_NESTING); |
| 5159 | |
| 5160 | pte = huge_ptep_get_and_clear(mm, old_addr, src_pte); |
| 5161 | set_huge_pte_at(mm, new_addr, dst_pte, pte); |
| 5162 | |
| 5163 | if (src_ptl != dst_ptl) |
| 5164 | spin_unlock(src_ptl); |
| 5165 | spin_unlock(dst_ptl); |
| 5166 | } |
| 5167 | |
| 5168 | int move_hugetlb_page_tables(struct vm_area_struct *vma, |
| 5169 | struct vm_area_struct *new_vma, |
| 5170 | unsigned long old_addr, unsigned long new_addr, |
| 5171 | unsigned long len) |
| 5172 | { |
| 5173 | struct hstate *h = hstate_vma(vma); |
| 5174 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 5175 | unsigned long sz = huge_page_size(h); |
| 5176 | struct mm_struct *mm = vma->vm_mm; |
| 5177 | unsigned long old_end = old_addr + len; |
| 5178 | unsigned long last_addr_mask; |
| 5179 | pte_t *src_pte, *dst_pte; |
| 5180 | struct mmu_notifier_range range; |
| 5181 | bool shared_pmd = false; |
| 5182 | |
| 5183 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, old_addr, |
| 5184 | old_end); |
| 5185 | adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); |
| 5186 | /* |
| 5187 | * In case of shared PMDs, we should cover the maximum possible |
| 5188 | * range. |
| 5189 | */ |
| 5190 | flush_cache_range(vma, range.start, range.end); |
| 5191 | |
| 5192 | mmu_notifier_invalidate_range_start(&range); |
| 5193 | last_addr_mask = hugetlb_mask_last_page(h); |
| 5194 | /* Prevent race with file truncation */ |
| 5195 | hugetlb_vma_lock_write(vma); |
| 5196 | i_mmap_lock_write(mapping); |
| 5197 | for (; old_addr < old_end; old_addr += sz, new_addr += sz) { |
| 5198 | src_pte = huge_pte_offset(mm, old_addr, sz); |
| 5199 | if (!src_pte) { |
| 5200 | old_addr |= last_addr_mask; |
| 5201 | new_addr |= last_addr_mask; |
| 5202 | continue; |
| 5203 | } |
| 5204 | if (huge_pte_none(huge_ptep_get(src_pte))) |
| 5205 | continue; |
| 5206 | |
| 5207 | if (huge_pmd_unshare(mm, vma, old_addr, src_pte)) { |
| 5208 | shared_pmd = true; |
| 5209 | old_addr |= last_addr_mask; |
| 5210 | new_addr |= last_addr_mask; |
| 5211 | continue; |
| 5212 | } |
| 5213 | |
| 5214 | dst_pte = huge_pte_alloc(mm, new_vma, new_addr, sz); |
| 5215 | if (!dst_pte) |
| 5216 | break; |
| 5217 | |
| 5218 | move_huge_pte(vma, old_addr, new_addr, src_pte, dst_pte); |
| 5219 | } |
| 5220 | |
| 5221 | if (shared_pmd) |
| 5222 | flush_tlb_range(vma, range.start, range.end); |
| 5223 | else |
| 5224 | flush_tlb_range(vma, old_end - len, old_end); |
| 5225 | mmu_notifier_invalidate_range_end(&range); |
| 5226 | i_mmap_unlock_write(mapping); |
| 5227 | hugetlb_vma_unlock_write(vma); |
| 5228 | |
| 5229 | return len + old_addr - old_end; |
| 5230 | } |
| 5231 | |
| 5232 | static void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, |
| 5233 | unsigned long start, unsigned long end, |
| 5234 | struct page *ref_page, zap_flags_t zap_flags) |
| 5235 | { |
| 5236 | struct mm_struct *mm = vma->vm_mm; |
| 5237 | unsigned long address; |
| 5238 | pte_t *ptep; |
| 5239 | pte_t pte; |
| 5240 | spinlock_t *ptl; |
| 5241 | struct page *page; |
| 5242 | struct hstate *h = hstate_vma(vma); |
| 5243 | unsigned long sz = huge_page_size(h); |
| 5244 | unsigned long last_addr_mask; |
| 5245 | bool force_flush = false; |
| 5246 | |
| 5247 | WARN_ON(!is_vm_hugetlb_page(vma)); |
| 5248 | BUG_ON(start & ~huge_page_mask(h)); |
| 5249 | BUG_ON(end & ~huge_page_mask(h)); |
| 5250 | |
| 5251 | /* |
| 5252 | * This is a hugetlb vma, all the pte entries should point |
| 5253 | * to huge page. |
| 5254 | */ |
| 5255 | tlb_change_page_size(tlb, sz); |
| 5256 | tlb_start_vma(tlb, vma); |
| 5257 | |
| 5258 | last_addr_mask = hugetlb_mask_last_page(h); |
| 5259 | address = start; |
| 5260 | for (; address < end; address += sz) { |
| 5261 | ptep = huge_pte_offset(mm, address, sz); |
| 5262 | if (!ptep) { |
| 5263 | address |= last_addr_mask; |
| 5264 | continue; |
| 5265 | } |
| 5266 | |
| 5267 | ptl = huge_pte_lock(h, mm, ptep); |
| 5268 | if (huge_pmd_unshare(mm, vma, address, ptep)) { |
| 5269 | spin_unlock(ptl); |
| 5270 | tlb_flush_pmd_range(tlb, address & PUD_MASK, PUD_SIZE); |
| 5271 | force_flush = true; |
| 5272 | address |= last_addr_mask; |
| 5273 | continue; |
| 5274 | } |
| 5275 | |
| 5276 | pte = huge_ptep_get(ptep); |
| 5277 | if (huge_pte_none(pte)) { |
| 5278 | spin_unlock(ptl); |
| 5279 | continue; |
| 5280 | } |
| 5281 | |
| 5282 | /* |
| 5283 | * Migrating hugepage or HWPoisoned hugepage is already |
| 5284 | * unmapped and its refcount is dropped, so just clear pte here. |
| 5285 | */ |
| 5286 | if (unlikely(!pte_present(pte))) { |
| 5287 | /* |
| 5288 | * If the pte was wr-protected by uffd-wp in any of the |
| 5289 | * swap forms, meanwhile the caller does not want to |
| 5290 | * drop the uffd-wp bit in this zap, then replace the |
| 5291 | * pte with a marker. |
| 5292 | */ |
| 5293 | if (pte_swp_uffd_wp_any(pte) && |
| 5294 | !(zap_flags & ZAP_FLAG_DROP_MARKER)) |
| 5295 | set_huge_pte_at(mm, address, ptep, |
| 5296 | make_pte_marker(PTE_MARKER_UFFD_WP)); |
| 5297 | else |
| 5298 | huge_pte_clear(mm, address, ptep, sz); |
| 5299 | spin_unlock(ptl); |
| 5300 | continue; |
| 5301 | } |
| 5302 | |
| 5303 | page = pte_page(pte); |
| 5304 | /* |
| 5305 | * If a reference page is supplied, it is because a specific |
| 5306 | * page is being unmapped, not a range. Ensure the page we |
| 5307 | * are about to unmap is the actual page of interest. |
| 5308 | */ |
| 5309 | if (ref_page) { |
| 5310 | if (page != ref_page) { |
| 5311 | spin_unlock(ptl); |
| 5312 | continue; |
| 5313 | } |
| 5314 | /* |
| 5315 | * Mark the VMA as having unmapped its page so that |
| 5316 | * future faults in this VMA will fail rather than |
| 5317 | * looking like data was lost |
| 5318 | */ |
| 5319 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
| 5320 | } |
| 5321 | |
| 5322 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
| 5323 | tlb_remove_huge_tlb_entry(h, tlb, ptep, address); |
| 5324 | if (huge_pte_dirty(pte)) |
| 5325 | set_page_dirty(page); |
| 5326 | /* Leave a uffd-wp pte marker if needed */ |
| 5327 | if (huge_pte_uffd_wp(pte) && |
| 5328 | !(zap_flags & ZAP_FLAG_DROP_MARKER)) |
| 5329 | set_huge_pte_at(mm, address, ptep, |
| 5330 | make_pte_marker(PTE_MARKER_UFFD_WP)); |
| 5331 | hugetlb_count_sub(pages_per_huge_page(h), mm); |
| 5332 | page_remove_rmap(page, vma, true); |
| 5333 | |
| 5334 | spin_unlock(ptl); |
| 5335 | tlb_remove_page_size(tlb, page, huge_page_size(h)); |
| 5336 | /* |
| 5337 | * Bail out after unmapping reference page if supplied |
| 5338 | */ |
| 5339 | if (ref_page) |
| 5340 | break; |
| 5341 | } |
| 5342 | tlb_end_vma(tlb, vma); |
| 5343 | |
| 5344 | /* |
| 5345 | * If we unshared PMDs, the TLB flush was not recorded in mmu_gather. We |
| 5346 | * could defer the flush until now, since by holding i_mmap_rwsem we |
| 5347 | * guaranteed that the last refernece would not be dropped. But we must |
| 5348 | * do the flushing before we return, as otherwise i_mmap_rwsem will be |
| 5349 | * dropped and the last reference to the shared PMDs page might be |
| 5350 | * dropped as well. |
| 5351 | * |
| 5352 | * In theory we could defer the freeing of the PMD pages as well, but |
| 5353 | * huge_pmd_unshare() relies on the exact page_count for the PMD page to |
| 5354 | * detect sharing, so we cannot defer the release of the page either. |
| 5355 | * Instead, do flush now. |
| 5356 | */ |
| 5357 | if (force_flush) |
| 5358 | tlb_flush_mmu_tlbonly(tlb); |
| 5359 | } |
| 5360 | |
| 5361 | void __unmap_hugepage_range_final(struct mmu_gather *tlb, |
| 5362 | struct vm_area_struct *vma, unsigned long start, |
| 5363 | unsigned long end, struct page *ref_page, |
| 5364 | zap_flags_t zap_flags) |
| 5365 | { |
| 5366 | hugetlb_vma_lock_write(vma); |
| 5367 | i_mmap_lock_write(vma->vm_file->f_mapping); |
| 5368 | |
| 5369 | /* mmu notification performed in caller */ |
| 5370 | __unmap_hugepage_range(tlb, vma, start, end, ref_page, zap_flags); |
| 5371 | |
| 5372 | if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */ |
| 5373 | /* |
| 5374 | * Unlock and free the vma lock before releasing i_mmap_rwsem. |
| 5375 | * When the vma_lock is freed, this makes the vma ineligible |
| 5376 | * for pmd sharing. And, i_mmap_rwsem is required to set up |
| 5377 | * pmd sharing. This is important as page tables for this |
| 5378 | * unmapped range will be asynchrously deleted. If the page |
| 5379 | * tables are shared, there will be issues when accessed by |
| 5380 | * someone else. |
| 5381 | */ |
| 5382 | __hugetlb_vma_unlock_write_free(vma); |
| 5383 | i_mmap_unlock_write(vma->vm_file->f_mapping); |
| 5384 | } else { |
| 5385 | i_mmap_unlock_write(vma->vm_file->f_mapping); |
| 5386 | hugetlb_vma_unlock_write(vma); |
| 5387 | } |
| 5388 | } |
| 5389 | |
| 5390 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| 5391 | unsigned long end, struct page *ref_page, |
| 5392 | zap_flags_t zap_flags) |
| 5393 | { |
| 5394 | struct mmu_notifier_range range; |
| 5395 | struct mmu_gather tlb; |
| 5396 | |
| 5397 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm, |
| 5398 | start, end); |
| 5399 | adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); |
| 5400 | mmu_notifier_invalidate_range_start(&range); |
| 5401 | tlb_gather_mmu(&tlb, vma->vm_mm); |
| 5402 | |
| 5403 | __unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags); |
| 5404 | |
| 5405 | mmu_notifier_invalidate_range_end(&range); |
| 5406 | tlb_finish_mmu(&tlb); |
| 5407 | } |
| 5408 | |
| 5409 | /* |
| 5410 | * This is called when the original mapper is failing to COW a MAP_PRIVATE |
| 5411 | * mapping it owns the reserve page for. The intention is to unmap the page |
| 5412 | * from other VMAs and let the children be SIGKILLed if they are faulting the |
| 5413 | * same region. |
| 5414 | */ |
| 5415 | static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, |
| 5416 | struct page *page, unsigned long address) |
| 5417 | { |
| 5418 | struct hstate *h = hstate_vma(vma); |
| 5419 | struct vm_area_struct *iter_vma; |
| 5420 | struct address_space *mapping; |
| 5421 | pgoff_t pgoff; |
| 5422 | |
| 5423 | /* |
| 5424 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
| 5425 | * from page cache lookup which is in HPAGE_SIZE units. |
| 5426 | */ |
| 5427 | address = address & huge_page_mask(h); |
| 5428 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) + |
| 5429 | vma->vm_pgoff; |
| 5430 | mapping = vma->vm_file->f_mapping; |
| 5431 | |
| 5432 | /* |
| 5433 | * Take the mapping lock for the duration of the table walk. As |
| 5434 | * this mapping should be shared between all the VMAs, |
| 5435 | * __unmap_hugepage_range() is called as the lock is already held |
| 5436 | */ |
| 5437 | i_mmap_lock_write(mapping); |
| 5438 | vma_interval_tree_foreach(iter_vma, &mapping->i_mmap, pgoff, pgoff) { |
| 5439 | /* Do not unmap the current VMA */ |
| 5440 | if (iter_vma == vma) |
| 5441 | continue; |
| 5442 | |
| 5443 | /* |
| 5444 | * Shared VMAs have their own reserves and do not affect |
| 5445 | * MAP_PRIVATE accounting but it is possible that a shared |
| 5446 | * VMA is using the same page so check and skip such VMAs. |
| 5447 | */ |
| 5448 | if (iter_vma->vm_flags & VM_MAYSHARE) |
| 5449 | continue; |
| 5450 | |
| 5451 | /* |
| 5452 | * Unmap the page from other VMAs without their own reserves. |
| 5453 | * They get marked to be SIGKILLed if they fault in these |
| 5454 | * areas. This is because a future no-page fault on this VMA |
| 5455 | * could insert a zeroed page instead of the data existing |
| 5456 | * from the time of fork. This would look like data corruption |
| 5457 | */ |
| 5458 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
| 5459 | unmap_hugepage_range(iter_vma, address, |
| 5460 | address + huge_page_size(h), page, 0); |
| 5461 | } |
| 5462 | i_mmap_unlock_write(mapping); |
| 5463 | } |
| 5464 | |
| 5465 | /* |
| 5466 | * hugetlb_wp() should be called with page lock of the original hugepage held. |
| 5467 | * Called with hugetlb_fault_mutex_table held and pte_page locked so we |
| 5468 | * cannot race with other handlers or page migration. |
| 5469 | * Keep the pte_same checks anyway to make transition from the mutex easier. |
| 5470 | */ |
| 5471 | static vm_fault_t hugetlb_wp(struct mm_struct *mm, struct vm_area_struct *vma, |
| 5472 | unsigned long address, pte_t *ptep, unsigned int flags, |
| 5473 | struct page *pagecache_page, spinlock_t *ptl) |
| 5474 | { |
| 5475 | const bool unshare = flags & FAULT_FLAG_UNSHARE; |
| 5476 | pte_t pte; |
| 5477 | struct hstate *h = hstate_vma(vma); |
| 5478 | struct page *old_page, *new_page; |
| 5479 | int outside_reserve = 0; |
| 5480 | vm_fault_t ret = 0; |
| 5481 | unsigned long haddr = address & huge_page_mask(h); |
| 5482 | struct mmu_notifier_range range; |
| 5483 | |
| 5484 | /* |
| 5485 | * hugetlb does not support FOLL_FORCE-style write faults that keep the |
| 5486 | * PTE mapped R/O such as maybe_mkwrite() would do. |
| 5487 | */ |
| 5488 | if (WARN_ON_ONCE(!unshare && !(vma->vm_flags & VM_WRITE))) |
| 5489 | return VM_FAULT_SIGSEGV; |
| 5490 | |
| 5491 | /* Let's take out MAP_SHARED mappings first. */ |
| 5492 | if (vma->vm_flags & VM_MAYSHARE) { |
| 5493 | set_huge_ptep_writable(vma, haddr, ptep); |
| 5494 | return 0; |
| 5495 | } |
| 5496 | |
| 5497 | pte = huge_ptep_get(ptep); |
| 5498 | old_page = pte_page(pte); |
| 5499 | |
| 5500 | delayacct_wpcopy_start(); |
| 5501 | |
| 5502 | retry_avoidcopy: |
| 5503 | /* |
| 5504 | * If no-one else is actually using this page, we're the exclusive |
| 5505 | * owner and can reuse this page. |
| 5506 | */ |
| 5507 | if (page_mapcount(old_page) == 1 && PageAnon(old_page)) { |
| 5508 | if (!PageAnonExclusive(old_page)) |
| 5509 | page_move_anon_rmap(old_page, vma); |
| 5510 | if (likely(!unshare)) |
| 5511 | set_huge_ptep_writable(vma, haddr, ptep); |
| 5512 | |
| 5513 | delayacct_wpcopy_end(); |
| 5514 | return 0; |
| 5515 | } |
| 5516 | VM_BUG_ON_PAGE(PageAnon(old_page) && PageAnonExclusive(old_page), |
| 5517 | old_page); |
| 5518 | |
| 5519 | /* |
| 5520 | * If the process that created a MAP_PRIVATE mapping is about to |
| 5521 | * perform a COW due to a shared page count, attempt to satisfy |
| 5522 | * the allocation without using the existing reserves. The pagecache |
| 5523 | * page is used to determine if the reserve at this address was |
| 5524 | * consumed or not. If reserves were used, a partial faulted mapping |
| 5525 | * at the time of fork() could consume its reserves on COW instead |
| 5526 | * of the full address range. |
| 5527 | */ |
| 5528 | if (is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
| 5529 | old_page != pagecache_page) |
| 5530 | outside_reserve = 1; |
| 5531 | |
| 5532 | get_page(old_page); |
| 5533 | |
| 5534 | /* |
| 5535 | * Drop page table lock as buddy allocator may be called. It will |
| 5536 | * be acquired again before returning to the caller, as expected. |
| 5537 | */ |
| 5538 | spin_unlock(ptl); |
| 5539 | new_page = alloc_huge_page(vma, haddr, outside_reserve); |
| 5540 | |
| 5541 | if (IS_ERR(new_page)) { |
| 5542 | /* |
| 5543 | * If a process owning a MAP_PRIVATE mapping fails to COW, |
| 5544 | * it is due to references held by a child and an insufficient |
| 5545 | * huge page pool. To guarantee the original mappers |
| 5546 | * reliability, unmap the page from child processes. The child |
| 5547 | * may get SIGKILLed if it later faults. |
| 5548 | */ |
| 5549 | if (outside_reserve) { |
| 5550 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 5551 | pgoff_t idx; |
| 5552 | u32 hash; |
| 5553 | |
| 5554 | put_page(old_page); |
| 5555 | /* |
| 5556 | * Drop hugetlb_fault_mutex and vma_lock before |
| 5557 | * unmapping. unmapping needs to hold vma_lock |
| 5558 | * in write mode. Dropping vma_lock in read mode |
| 5559 | * here is OK as COW mappings do not interact with |
| 5560 | * PMD sharing. |
| 5561 | * |
| 5562 | * Reacquire both after unmap operation. |
| 5563 | */ |
| 5564 | idx = vma_hugecache_offset(h, vma, haddr); |
| 5565 | hash = hugetlb_fault_mutex_hash(mapping, idx); |
| 5566 | hugetlb_vma_unlock_read(vma); |
| 5567 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| 5568 | |
| 5569 | unmap_ref_private(mm, vma, old_page, haddr); |
| 5570 | |
| 5571 | mutex_lock(&hugetlb_fault_mutex_table[hash]); |
| 5572 | hugetlb_vma_lock_read(vma); |
| 5573 | spin_lock(ptl); |
| 5574 | ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); |
| 5575 | if (likely(ptep && |
| 5576 | pte_same(huge_ptep_get(ptep), pte))) |
| 5577 | goto retry_avoidcopy; |
| 5578 | /* |
| 5579 | * race occurs while re-acquiring page table |
| 5580 | * lock, and our job is done. |
| 5581 | */ |
| 5582 | delayacct_wpcopy_end(); |
| 5583 | return 0; |
| 5584 | } |
| 5585 | |
| 5586 | ret = vmf_error(PTR_ERR(new_page)); |
| 5587 | goto out_release_old; |
| 5588 | } |
| 5589 | |
| 5590 | /* |
| 5591 | * When the original hugepage is shared one, it does not have |
| 5592 | * anon_vma prepared. |
| 5593 | */ |
| 5594 | if (unlikely(anon_vma_prepare(vma))) { |
| 5595 | ret = VM_FAULT_OOM; |
| 5596 | goto out_release_all; |
| 5597 | } |
| 5598 | |
| 5599 | copy_user_huge_page(new_page, old_page, address, vma, |
| 5600 | pages_per_huge_page(h)); |
| 5601 | __SetPageUptodate(new_page); |
| 5602 | |
| 5603 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, haddr, |
| 5604 | haddr + huge_page_size(h)); |
| 5605 | mmu_notifier_invalidate_range_start(&range); |
| 5606 | |
| 5607 | /* |
| 5608 | * Retake the page table lock to check for racing updates |
| 5609 | * before the page tables are altered |
| 5610 | */ |
| 5611 | spin_lock(ptl); |
| 5612 | ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); |
| 5613 | if (likely(ptep && pte_same(huge_ptep_get(ptep), pte))) { |
| 5614 | /* Break COW or unshare */ |
| 5615 | huge_ptep_clear_flush(vma, haddr, ptep); |
| 5616 | mmu_notifier_invalidate_range(mm, range.start, range.end); |
| 5617 | page_remove_rmap(old_page, vma, true); |
| 5618 | hugepage_add_new_anon_rmap(new_page, vma, haddr); |
| 5619 | set_huge_pte_at(mm, haddr, ptep, |
| 5620 | make_huge_pte(vma, new_page, !unshare)); |
| 5621 | SetHPageMigratable(new_page); |
| 5622 | /* Make the old page be freed below */ |
| 5623 | new_page = old_page; |
| 5624 | } |
| 5625 | spin_unlock(ptl); |
| 5626 | mmu_notifier_invalidate_range_end(&range); |
| 5627 | out_release_all: |
| 5628 | /* |
| 5629 | * No restore in case of successful pagetable update (Break COW or |
| 5630 | * unshare) |
| 5631 | */ |
| 5632 | if (new_page != old_page) |
| 5633 | restore_reserve_on_error(h, vma, haddr, new_page); |
| 5634 | put_page(new_page); |
| 5635 | out_release_old: |
| 5636 | put_page(old_page); |
| 5637 | |
| 5638 | spin_lock(ptl); /* Caller expects lock to be held */ |
| 5639 | |
| 5640 | delayacct_wpcopy_end(); |
| 5641 | return ret; |
| 5642 | } |
| 5643 | |
| 5644 | /* |
| 5645 | * Return whether there is a pagecache page to back given address within VMA. |
| 5646 | * Caller follow_hugetlb_page() holds page_table_lock so we cannot lock_page. |
| 5647 | */ |
| 5648 | static bool hugetlbfs_pagecache_present(struct hstate *h, |
| 5649 | struct vm_area_struct *vma, unsigned long address) |
| 5650 | { |
| 5651 | struct address_space *mapping; |
| 5652 | pgoff_t idx; |
| 5653 | struct page *page; |
| 5654 | |
| 5655 | mapping = vma->vm_file->f_mapping; |
| 5656 | idx = vma_hugecache_offset(h, vma, address); |
| 5657 | |
| 5658 | page = find_get_page(mapping, idx); |
| 5659 | if (page) |
| 5660 | put_page(page); |
| 5661 | return page != NULL; |
| 5662 | } |
| 5663 | |
| 5664 | int hugetlb_add_to_page_cache(struct page *page, struct address_space *mapping, |
| 5665 | pgoff_t idx) |
| 5666 | { |
| 5667 | struct folio *folio = page_folio(page); |
| 5668 | struct inode *inode = mapping->host; |
| 5669 | struct hstate *h = hstate_inode(inode); |
| 5670 | int err; |
| 5671 | |
| 5672 | __folio_set_locked(folio); |
| 5673 | err = __filemap_add_folio(mapping, folio, idx, GFP_KERNEL, NULL); |
| 5674 | |
| 5675 | if (unlikely(err)) { |
| 5676 | __folio_clear_locked(folio); |
| 5677 | return err; |
| 5678 | } |
| 5679 | ClearHPageRestoreReserve(page); |
| 5680 | |
| 5681 | /* |
| 5682 | * mark folio dirty so that it will not be removed from cache/file |
| 5683 | * by non-hugetlbfs specific code paths. |
| 5684 | */ |
| 5685 | folio_mark_dirty(folio); |
| 5686 | |
| 5687 | spin_lock(&inode->i_lock); |
| 5688 | inode->i_blocks += blocks_per_huge_page(h); |
| 5689 | spin_unlock(&inode->i_lock); |
| 5690 | return 0; |
| 5691 | } |
| 5692 | |
| 5693 | static inline vm_fault_t hugetlb_handle_userfault(struct vm_area_struct *vma, |
| 5694 | struct address_space *mapping, |
| 5695 | pgoff_t idx, |
| 5696 | unsigned int flags, |
| 5697 | unsigned long haddr, |
| 5698 | unsigned long addr, |
| 5699 | unsigned long reason) |
| 5700 | { |
| 5701 | u32 hash; |
| 5702 | struct vm_fault vmf = { |
| 5703 | .vma = vma, |
| 5704 | .address = haddr, |
| 5705 | .real_address = addr, |
| 5706 | .flags = flags, |
| 5707 | |
| 5708 | /* |
| 5709 | * Hard to debug if it ends up being |
| 5710 | * used by a callee that assumes |
| 5711 | * something about the other |
| 5712 | * uninitialized fields... same as in |
| 5713 | * memory.c |
| 5714 | */ |
| 5715 | }; |
| 5716 | |
| 5717 | /* |
| 5718 | * vma_lock and hugetlb_fault_mutex must be dropped before handling |
| 5719 | * userfault. Also mmap_lock could be dropped due to handling |
| 5720 | * userfault, any vma operation should be careful from here. |
| 5721 | */ |
| 5722 | hugetlb_vma_unlock_read(vma); |
| 5723 | hash = hugetlb_fault_mutex_hash(mapping, idx); |
| 5724 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| 5725 | return handle_userfault(&vmf, reason); |
| 5726 | } |
| 5727 | |
| 5728 | /* |
| 5729 | * Recheck pte with pgtable lock. Returns true if pte didn't change, or |
| 5730 | * false if pte changed or is changing. |
| 5731 | */ |
| 5732 | static bool hugetlb_pte_stable(struct hstate *h, struct mm_struct *mm, |
| 5733 | pte_t *ptep, pte_t old_pte) |
| 5734 | { |
| 5735 | spinlock_t *ptl; |
| 5736 | bool same; |
| 5737 | |
| 5738 | ptl = huge_pte_lock(h, mm, ptep); |
| 5739 | same = pte_same(huge_ptep_get(ptep), old_pte); |
| 5740 | spin_unlock(ptl); |
| 5741 | |
| 5742 | return same; |
| 5743 | } |
| 5744 | |
| 5745 | static vm_fault_t hugetlb_no_page(struct mm_struct *mm, |
| 5746 | struct vm_area_struct *vma, |
| 5747 | struct address_space *mapping, pgoff_t idx, |
| 5748 | unsigned long address, pte_t *ptep, |
| 5749 | pte_t old_pte, unsigned int flags) |
| 5750 | { |
| 5751 | struct hstate *h = hstate_vma(vma); |
| 5752 | vm_fault_t ret = VM_FAULT_SIGBUS; |
| 5753 | int anon_rmap = 0; |
| 5754 | unsigned long size; |
| 5755 | struct page *page; |
| 5756 | pte_t new_pte; |
| 5757 | spinlock_t *ptl; |
| 5758 | unsigned long haddr = address & huge_page_mask(h); |
| 5759 | bool new_page, new_pagecache_page = false; |
| 5760 | u32 hash = hugetlb_fault_mutex_hash(mapping, idx); |
| 5761 | |
| 5762 | /* |
| 5763 | * Currently, we are forced to kill the process in the event the |
| 5764 | * original mapper has unmapped pages from the child due to a failed |
| 5765 | * COW/unsharing. Warn that such a situation has occurred as it may not |
| 5766 | * be obvious. |
| 5767 | */ |
| 5768 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
| 5769 | pr_warn_ratelimited("PID %d killed due to inadequate hugepage pool\n", |
| 5770 | current->pid); |
| 5771 | goto out; |
| 5772 | } |
| 5773 | |
| 5774 | /* |
| 5775 | * Use page lock to guard against racing truncation |
| 5776 | * before we get page_table_lock. |
| 5777 | */ |
| 5778 | new_page = false; |
| 5779 | page = find_lock_page(mapping, idx); |
| 5780 | if (!page) { |
| 5781 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
| 5782 | if (idx >= size) |
| 5783 | goto out; |
| 5784 | /* Check for page in userfault range */ |
| 5785 | if (userfaultfd_missing(vma)) { |
| 5786 | /* |
| 5787 | * Since hugetlb_no_page() was examining pte |
| 5788 | * without pgtable lock, we need to re-test under |
| 5789 | * lock because the pte may not be stable and could |
| 5790 | * have changed from under us. Try to detect |
| 5791 | * either changed or during-changing ptes and retry |
| 5792 | * properly when needed. |
| 5793 | * |
| 5794 | * Note that userfaultfd is actually fine with |
| 5795 | * false positives (e.g. caused by pte changed), |
| 5796 | * but not wrong logical events (e.g. caused by |
| 5797 | * reading a pte during changing). The latter can |
| 5798 | * confuse the userspace, so the strictness is very |
| 5799 | * much preferred. E.g., MISSING event should |
| 5800 | * never happen on the page after UFFDIO_COPY has |
| 5801 | * correctly installed the page and returned. |
| 5802 | */ |
| 5803 | if (!hugetlb_pte_stable(h, mm, ptep, old_pte)) { |
| 5804 | ret = 0; |
| 5805 | goto out; |
| 5806 | } |
| 5807 | |
| 5808 | return hugetlb_handle_userfault(vma, mapping, idx, flags, |
| 5809 | haddr, address, |
| 5810 | VM_UFFD_MISSING); |
| 5811 | } |
| 5812 | |
| 5813 | page = alloc_huge_page(vma, haddr, 0); |
| 5814 | if (IS_ERR(page)) { |
| 5815 | /* |
| 5816 | * Returning error will result in faulting task being |
| 5817 | * sent SIGBUS. The hugetlb fault mutex prevents two |
| 5818 | * tasks from racing to fault in the same page which |
| 5819 | * could result in false unable to allocate errors. |
| 5820 | * Page migration does not take the fault mutex, but |
| 5821 | * does a clear then write of pte's under page table |
| 5822 | * lock. Page fault code could race with migration, |
| 5823 | * notice the clear pte and try to allocate a page |
| 5824 | * here. Before returning error, get ptl and make |
| 5825 | * sure there really is no pte entry. |
| 5826 | */ |
| 5827 | if (hugetlb_pte_stable(h, mm, ptep, old_pte)) |
| 5828 | ret = vmf_error(PTR_ERR(page)); |
| 5829 | else |
| 5830 | ret = 0; |
| 5831 | goto out; |
| 5832 | } |
| 5833 | clear_huge_page(page, address, pages_per_huge_page(h)); |
| 5834 | __SetPageUptodate(page); |
| 5835 | new_page = true; |
| 5836 | |
| 5837 | if (vma->vm_flags & VM_MAYSHARE) { |
| 5838 | int err = hugetlb_add_to_page_cache(page, mapping, idx); |
| 5839 | if (err) { |
| 5840 | /* |
| 5841 | * err can't be -EEXIST which implies someone |
| 5842 | * else consumed the reservation since hugetlb |
| 5843 | * fault mutex is held when add a hugetlb page |
| 5844 | * to the page cache. So it's safe to call |
| 5845 | * restore_reserve_on_error() here. |
| 5846 | */ |
| 5847 | restore_reserve_on_error(h, vma, haddr, page); |
| 5848 | put_page(page); |
| 5849 | goto out; |
| 5850 | } |
| 5851 | new_pagecache_page = true; |
| 5852 | } else { |
| 5853 | lock_page(page); |
| 5854 | if (unlikely(anon_vma_prepare(vma))) { |
| 5855 | ret = VM_FAULT_OOM; |
| 5856 | goto backout_unlocked; |
| 5857 | } |
| 5858 | anon_rmap = 1; |
| 5859 | } |
| 5860 | } else { |
| 5861 | /* |
| 5862 | * If memory error occurs between mmap() and fault, some process |
| 5863 | * don't have hwpoisoned swap entry for errored virtual address. |
| 5864 | * So we need to block hugepage fault by PG_hwpoison bit check. |
| 5865 | */ |
| 5866 | if (unlikely(PageHWPoison(page))) { |
| 5867 | ret = VM_FAULT_HWPOISON_LARGE | |
| 5868 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
| 5869 | goto backout_unlocked; |
| 5870 | } |
| 5871 | |
| 5872 | /* Check for page in userfault range. */ |
| 5873 | if (userfaultfd_minor(vma)) { |
| 5874 | unlock_page(page); |
| 5875 | put_page(page); |
| 5876 | /* See comment in userfaultfd_missing() block above */ |
| 5877 | if (!hugetlb_pte_stable(h, mm, ptep, old_pte)) { |
| 5878 | ret = 0; |
| 5879 | goto out; |
| 5880 | } |
| 5881 | return hugetlb_handle_userfault(vma, mapping, idx, flags, |
| 5882 | haddr, address, |
| 5883 | VM_UFFD_MINOR); |
| 5884 | } |
| 5885 | } |
| 5886 | |
| 5887 | /* |
| 5888 | * If we are going to COW a private mapping later, we examine the |
| 5889 | * pending reservations for this page now. This will ensure that |
| 5890 | * any allocations necessary to record that reservation occur outside |
| 5891 | * the spinlock. |
| 5892 | */ |
| 5893 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
| 5894 | if (vma_needs_reservation(h, vma, haddr) < 0) { |
| 5895 | ret = VM_FAULT_OOM; |
| 5896 | goto backout_unlocked; |
| 5897 | } |
| 5898 | /* Just decrements count, does not deallocate */ |
| 5899 | vma_end_reservation(h, vma, haddr); |
| 5900 | } |
| 5901 | |
| 5902 | ptl = huge_pte_lock(h, mm, ptep); |
| 5903 | ret = 0; |
| 5904 | /* If pte changed from under us, retry */ |
| 5905 | if (!pte_same(huge_ptep_get(ptep), old_pte)) |
| 5906 | goto backout; |
| 5907 | |
| 5908 | if (anon_rmap) |
| 5909 | hugepage_add_new_anon_rmap(page, vma, haddr); |
| 5910 | else |
| 5911 | page_dup_file_rmap(page, true); |
| 5912 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
| 5913 | && (vma->vm_flags & VM_SHARED))); |
| 5914 | /* |
| 5915 | * If this pte was previously wr-protected, keep it wr-protected even |
| 5916 | * if populated. |
| 5917 | */ |
| 5918 | if (unlikely(pte_marker_uffd_wp(old_pte))) |
| 5919 | new_pte = huge_pte_wrprotect(huge_pte_mkuffd_wp(new_pte)); |
| 5920 | set_huge_pte_at(mm, haddr, ptep, new_pte); |
| 5921 | |
| 5922 | hugetlb_count_add(pages_per_huge_page(h), mm); |
| 5923 | if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { |
| 5924 | /* Optimization, do the COW without a second fault */ |
| 5925 | ret = hugetlb_wp(mm, vma, address, ptep, flags, page, ptl); |
| 5926 | } |
| 5927 | |
| 5928 | spin_unlock(ptl); |
| 5929 | |
| 5930 | /* |
| 5931 | * Only set HPageMigratable in newly allocated pages. Existing pages |
| 5932 | * found in the pagecache may not have HPageMigratableset if they have |
| 5933 | * been isolated for migration. |
| 5934 | */ |
| 5935 | if (new_page) |
| 5936 | SetHPageMigratable(page); |
| 5937 | |
| 5938 | unlock_page(page); |
| 5939 | out: |
| 5940 | hugetlb_vma_unlock_read(vma); |
| 5941 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| 5942 | return ret; |
| 5943 | |
| 5944 | backout: |
| 5945 | spin_unlock(ptl); |
| 5946 | backout_unlocked: |
| 5947 | if (new_page && !new_pagecache_page) |
| 5948 | restore_reserve_on_error(h, vma, haddr, page); |
| 5949 | |
| 5950 | unlock_page(page); |
| 5951 | put_page(page); |
| 5952 | goto out; |
| 5953 | } |
| 5954 | |
| 5955 | #ifdef CONFIG_SMP |
| 5956 | u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx) |
| 5957 | { |
| 5958 | unsigned long key[2]; |
| 5959 | u32 hash; |
| 5960 | |
| 5961 | key[0] = (unsigned long) mapping; |
| 5962 | key[1] = idx; |
| 5963 | |
| 5964 | hash = jhash2((u32 *)&key, sizeof(key)/(sizeof(u32)), 0); |
| 5965 | |
| 5966 | return hash & (num_fault_mutexes - 1); |
| 5967 | } |
| 5968 | #else |
| 5969 | /* |
| 5970 | * For uniprocessor systems we always use a single mutex, so just |
| 5971 | * return 0 and avoid the hashing overhead. |
| 5972 | */ |
| 5973 | u32 hugetlb_fault_mutex_hash(struct address_space *mapping, pgoff_t idx) |
| 5974 | { |
| 5975 | return 0; |
| 5976 | } |
| 5977 | #endif |
| 5978 | |
| 5979 | vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
| 5980 | unsigned long address, unsigned int flags) |
| 5981 | { |
| 5982 | pte_t *ptep, entry; |
| 5983 | spinlock_t *ptl; |
| 5984 | vm_fault_t ret; |
| 5985 | u32 hash; |
| 5986 | pgoff_t idx; |
| 5987 | struct page *page = NULL; |
| 5988 | struct page *pagecache_page = NULL; |
| 5989 | struct hstate *h = hstate_vma(vma); |
| 5990 | struct address_space *mapping; |
| 5991 | int need_wait_lock = 0; |
| 5992 | unsigned long haddr = address & huge_page_mask(h); |
| 5993 | |
| 5994 | ptep = huge_pte_offset(mm, haddr, huge_page_size(h)); |
| 5995 | if (ptep) { |
| 5996 | /* |
| 5997 | * Since we hold no locks, ptep could be stale. That is |
| 5998 | * OK as we are only making decisions based on content and |
| 5999 | * not actually modifying content here. |
| 6000 | */ |
| 6001 | entry = huge_ptep_get(ptep); |
| 6002 | if (unlikely(is_hugetlb_entry_migration(entry))) { |
| 6003 | migration_entry_wait_huge(vma, ptep); |
| 6004 | return 0; |
| 6005 | } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) |
| 6006 | return VM_FAULT_HWPOISON_LARGE | |
| 6007 | VM_FAULT_SET_HINDEX(hstate_index(h)); |
| 6008 | } |
| 6009 | |
| 6010 | /* |
| 6011 | * Serialize hugepage allocation and instantiation, so that we don't |
| 6012 | * get spurious allocation failures if two CPUs race to instantiate |
| 6013 | * the same page in the page cache. |
| 6014 | */ |
| 6015 | mapping = vma->vm_file->f_mapping; |
| 6016 | idx = vma_hugecache_offset(h, vma, haddr); |
| 6017 | hash = hugetlb_fault_mutex_hash(mapping, idx); |
| 6018 | mutex_lock(&hugetlb_fault_mutex_table[hash]); |
| 6019 | |
| 6020 | /* |
| 6021 | * Acquire vma lock before calling huge_pte_alloc and hold |
| 6022 | * until finished with ptep. This prevents huge_pmd_unshare from |
| 6023 | * being called elsewhere and making the ptep no longer valid. |
| 6024 | * |
| 6025 | * ptep could have already be assigned via huge_pte_offset. That |
| 6026 | * is OK, as huge_pte_alloc will return the same value unless |
| 6027 | * something has changed. |
| 6028 | */ |
| 6029 | hugetlb_vma_lock_read(vma); |
| 6030 | ptep = huge_pte_alloc(mm, vma, haddr, huge_page_size(h)); |
| 6031 | if (!ptep) { |
| 6032 | hugetlb_vma_unlock_read(vma); |
| 6033 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| 6034 | return VM_FAULT_OOM; |
| 6035 | } |
| 6036 | |
| 6037 | entry = huge_ptep_get(ptep); |
| 6038 | /* PTE markers should be handled the same way as none pte */ |
| 6039 | if (huge_pte_none_mostly(entry)) |
| 6040 | /* |
| 6041 | * hugetlb_no_page will drop vma lock and hugetlb fault |
| 6042 | * mutex internally, which make us return immediately. |
| 6043 | */ |
| 6044 | return hugetlb_no_page(mm, vma, mapping, idx, address, ptep, |
| 6045 | entry, flags); |
| 6046 | |
| 6047 | ret = 0; |
| 6048 | |
| 6049 | /* |
| 6050 | * entry could be a migration/hwpoison entry at this point, so this |
| 6051 | * check prevents the kernel from going below assuming that we have |
| 6052 | * an active hugepage in pagecache. This goto expects the 2nd page |
| 6053 | * fault, and is_hugetlb_entry_(migration|hwpoisoned) check will |
| 6054 | * properly handle it. |
| 6055 | */ |
| 6056 | if (!pte_present(entry)) |
| 6057 | goto out_mutex; |
| 6058 | |
| 6059 | /* |
| 6060 | * If we are going to COW/unshare the mapping later, we examine the |
| 6061 | * pending reservations for this page now. This will ensure that any |
| 6062 | * allocations necessary to record that reservation occur outside the |
| 6063 | * spinlock. Also lookup the pagecache page now as it is used to |
| 6064 | * determine if a reservation has been consumed. |
| 6065 | */ |
| 6066 | if ((flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) && |
| 6067 | !(vma->vm_flags & VM_MAYSHARE) && !huge_pte_write(entry)) { |
| 6068 | if (vma_needs_reservation(h, vma, haddr) < 0) { |
| 6069 | ret = VM_FAULT_OOM; |
| 6070 | goto out_mutex; |
| 6071 | } |
| 6072 | /* Just decrements count, does not deallocate */ |
| 6073 | vma_end_reservation(h, vma, haddr); |
| 6074 | |
| 6075 | pagecache_page = find_lock_page(mapping, idx); |
| 6076 | } |
| 6077 | |
| 6078 | ptl = huge_pte_lock(h, mm, ptep); |
| 6079 | |
| 6080 | /* Check for a racing update before calling hugetlb_wp() */ |
| 6081 | if (unlikely(!pte_same(entry, huge_ptep_get(ptep)))) |
| 6082 | goto out_ptl; |
| 6083 | |
| 6084 | /* Handle userfault-wp first, before trying to lock more pages */ |
| 6085 | if (userfaultfd_wp(vma) && huge_pte_uffd_wp(huge_ptep_get(ptep)) && |
| 6086 | (flags & FAULT_FLAG_WRITE) && !huge_pte_write(entry)) { |
| 6087 | struct vm_fault vmf = { |
| 6088 | .vma = vma, |
| 6089 | .address = haddr, |
| 6090 | .real_address = address, |
| 6091 | .flags = flags, |
| 6092 | }; |
| 6093 | |
| 6094 | spin_unlock(ptl); |
| 6095 | if (pagecache_page) { |
| 6096 | unlock_page(pagecache_page); |
| 6097 | put_page(pagecache_page); |
| 6098 | } |
| 6099 | hugetlb_vma_unlock_read(vma); |
| 6100 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| 6101 | return handle_userfault(&vmf, VM_UFFD_WP); |
| 6102 | } |
| 6103 | |
| 6104 | /* |
| 6105 | * hugetlb_wp() requires page locks of pte_page(entry) and |
| 6106 | * pagecache_page, so here we need take the former one |
| 6107 | * when page != pagecache_page or !pagecache_page. |
| 6108 | */ |
| 6109 | page = pte_page(entry); |
| 6110 | if (page != pagecache_page) |
| 6111 | if (!trylock_page(page)) { |
| 6112 | need_wait_lock = 1; |
| 6113 | goto out_ptl; |
| 6114 | } |
| 6115 | |
| 6116 | get_page(page); |
| 6117 | |
| 6118 | if (flags & (FAULT_FLAG_WRITE|FAULT_FLAG_UNSHARE)) { |
| 6119 | if (!huge_pte_write(entry)) { |
| 6120 | ret = hugetlb_wp(mm, vma, address, ptep, flags, |
| 6121 | pagecache_page, ptl); |
| 6122 | goto out_put_page; |
| 6123 | } else if (likely(flags & FAULT_FLAG_WRITE)) { |
| 6124 | entry = huge_pte_mkdirty(entry); |
| 6125 | } |
| 6126 | } |
| 6127 | entry = pte_mkyoung(entry); |
| 6128 | if (huge_ptep_set_access_flags(vma, haddr, ptep, entry, |
| 6129 | flags & FAULT_FLAG_WRITE)) |
| 6130 | update_mmu_cache(vma, haddr, ptep); |
| 6131 | out_put_page: |
| 6132 | if (page != pagecache_page) |
| 6133 | unlock_page(page); |
| 6134 | put_page(page); |
| 6135 | out_ptl: |
| 6136 | spin_unlock(ptl); |
| 6137 | |
| 6138 | if (pagecache_page) { |
| 6139 | unlock_page(pagecache_page); |
| 6140 | put_page(pagecache_page); |
| 6141 | } |
| 6142 | out_mutex: |
| 6143 | hugetlb_vma_unlock_read(vma); |
| 6144 | mutex_unlock(&hugetlb_fault_mutex_table[hash]); |
| 6145 | /* |
| 6146 | * Generally it's safe to hold refcount during waiting page lock. But |
| 6147 | * here we just wait to defer the next page fault to avoid busy loop and |
| 6148 | * the page is not used after unlocked before returning from the current |
| 6149 | * page fault. So we are safe from accessing freed page, even if we wait |
| 6150 | * here without taking refcount. |
| 6151 | */ |
| 6152 | if (need_wait_lock) |
| 6153 | wait_on_page_locked(page); |
| 6154 | return ret; |
| 6155 | } |
| 6156 | |
| 6157 | #ifdef CONFIG_USERFAULTFD |
| 6158 | /* |
| 6159 | * Used by userfaultfd UFFDIO_COPY. Based on mcopy_atomic_pte with |
| 6160 | * modifications for huge pages. |
| 6161 | */ |
| 6162 | int hugetlb_mcopy_atomic_pte(struct mm_struct *dst_mm, |
| 6163 | pte_t *dst_pte, |
| 6164 | struct vm_area_struct *dst_vma, |
| 6165 | unsigned long dst_addr, |
| 6166 | unsigned long src_addr, |
| 6167 | enum mcopy_atomic_mode mode, |
| 6168 | struct page **pagep, |
| 6169 | bool wp_copy) |
| 6170 | { |
| 6171 | bool is_continue = (mode == MCOPY_ATOMIC_CONTINUE); |
| 6172 | struct hstate *h = hstate_vma(dst_vma); |
| 6173 | struct address_space *mapping = dst_vma->vm_file->f_mapping; |
| 6174 | pgoff_t idx = vma_hugecache_offset(h, dst_vma, dst_addr); |
| 6175 | unsigned long size; |
| 6176 | int vm_shared = dst_vma->vm_flags & VM_SHARED; |
| 6177 | pte_t _dst_pte; |
| 6178 | spinlock_t *ptl; |
| 6179 | int ret = -ENOMEM; |
| 6180 | struct page *page; |
| 6181 | int writable; |
| 6182 | bool page_in_pagecache = false; |
| 6183 | |
| 6184 | if (is_continue) { |
| 6185 | ret = -EFAULT; |
| 6186 | page = find_lock_page(mapping, idx); |
| 6187 | if (!page) |
| 6188 | goto out; |
| 6189 | page_in_pagecache = true; |
| 6190 | } else if (!*pagep) { |
| 6191 | /* If a page already exists, then it's UFFDIO_COPY for |
| 6192 | * a non-missing case. Return -EEXIST. |
| 6193 | */ |
| 6194 | if (vm_shared && |
| 6195 | hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) { |
| 6196 | ret = -EEXIST; |
| 6197 | goto out; |
| 6198 | } |
| 6199 | |
| 6200 | page = alloc_huge_page(dst_vma, dst_addr, 0); |
| 6201 | if (IS_ERR(page)) { |
| 6202 | ret = -ENOMEM; |
| 6203 | goto out; |
| 6204 | } |
| 6205 | |
| 6206 | ret = copy_huge_page_from_user(page, |
| 6207 | (const void __user *) src_addr, |
| 6208 | pages_per_huge_page(h), false); |
| 6209 | |
| 6210 | /* fallback to copy_from_user outside mmap_lock */ |
| 6211 | if (unlikely(ret)) { |
| 6212 | ret = -ENOENT; |
| 6213 | /* Free the allocated page which may have |
| 6214 | * consumed a reservation. |
| 6215 | */ |
| 6216 | restore_reserve_on_error(h, dst_vma, dst_addr, page); |
| 6217 | put_page(page); |
| 6218 | |
| 6219 | /* Allocate a temporary page to hold the copied |
| 6220 | * contents. |
| 6221 | */ |
| 6222 | page = alloc_huge_page_vma(h, dst_vma, dst_addr); |
| 6223 | if (!page) { |
| 6224 | ret = -ENOMEM; |
| 6225 | goto out; |
| 6226 | } |
| 6227 | *pagep = page; |
| 6228 | /* Set the outparam pagep and return to the caller to |
| 6229 | * copy the contents outside the lock. Don't free the |
| 6230 | * page. |
| 6231 | */ |
| 6232 | goto out; |
| 6233 | } |
| 6234 | } else { |
| 6235 | if (vm_shared && |
| 6236 | hugetlbfs_pagecache_present(h, dst_vma, dst_addr)) { |
| 6237 | put_page(*pagep); |
| 6238 | ret = -EEXIST; |
| 6239 | *pagep = NULL; |
| 6240 | goto out; |
| 6241 | } |
| 6242 | |
| 6243 | page = alloc_huge_page(dst_vma, dst_addr, 0); |
| 6244 | if (IS_ERR(page)) { |
| 6245 | put_page(*pagep); |
| 6246 | ret = -ENOMEM; |
| 6247 | *pagep = NULL; |
| 6248 | goto out; |
| 6249 | } |
| 6250 | copy_user_huge_page(page, *pagep, dst_addr, dst_vma, |
| 6251 | pages_per_huge_page(h)); |
| 6252 | put_page(*pagep); |
| 6253 | *pagep = NULL; |
| 6254 | } |
| 6255 | |
| 6256 | /* |
| 6257 | * The memory barrier inside __SetPageUptodate makes sure that |
| 6258 | * preceding stores to the page contents become visible before |
| 6259 | * the set_pte_at() write. |
| 6260 | */ |
| 6261 | __SetPageUptodate(page); |
| 6262 | |
| 6263 | /* Add shared, newly allocated pages to the page cache. */ |
| 6264 | if (vm_shared && !is_continue) { |
| 6265 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
| 6266 | ret = -EFAULT; |
| 6267 | if (idx >= size) |
| 6268 | goto out_release_nounlock; |
| 6269 | |
| 6270 | /* |
| 6271 | * Serialization between remove_inode_hugepages() and |
| 6272 | * hugetlb_add_to_page_cache() below happens through the |
| 6273 | * hugetlb_fault_mutex_table that here must be hold by |
| 6274 | * the caller. |
| 6275 | */ |
| 6276 | ret = hugetlb_add_to_page_cache(page, mapping, idx); |
| 6277 | if (ret) |
| 6278 | goto out_release_nounlock; |
| 6279 | page_in_pagecache = true; |
| 6280 | } |
| 6281 | |
| 6282 | ptl = huge_pte_lock(h, dst_mm, dst_pte); |
| 6283 | |
| 6284 | ret = -EIO; |
| 6285 | if (PageHWPoison(page)) |
| 6286 | goto out_release_unlock; |
| 6287 | |
| 6288 | /* |
| 6289 | * We allow to overwrite a pte marker: consider when both MISSING|WP |
| 6290 | * registered, we firstly wr-protect a none pte which has no page cache |
| 6291 | * page backing it, then access the page. |
| 6292 | */ |
| 6293 | ret = -EEXIST; |
| 6294 | if (!huge_pte_none_mostly(huge_ptep_get(dst_pte))) |
| 6295 | goto out_release_unlock; |
| 6296 | |
| 6297 | if (page_in_pagecache) |
| 6298 | page_dup_file_rmap(page, true); |
| 6299 | else |
| 6300 | hugepage_add_new_anon_rmap(page, dst_vma, dst_addr); |
| 6301 | |
| 6302 | /* |
| 6303 | * For either: (1) CONTINUE on a non-shared VMA, or (2) UFFDIO_COPY |
| 6304 | * with wp flag set, don't set pte write bit. |
| 6305 | */ |
| 6306 | if (wp_copy || (is_continue && !vm_shared)) |
| 6307 | writable = 0; |
| 6308 | else |
| 6309 | writable = dst_vma->vm_flags & VM_WRITE; |
| 6310 | |
| 6311 | _dst_pte = make_huge_pte(dst_vma, page, writable); |
| 6312 | /* |
| 6313 | * Always mark UFFDIO_COPY page dirty; note that this may not be |
| 6314 | * extremely important for hugetlbfs for now since swapping is not |
| 6315 | * supported, but we should still be clear in that this page cannot be |
| 6316 | * thrown away at will, even if write bit not set. |
| 6317 | */ |
| 6318 | _dst_pte = huge_pte_mkdirty(_dst_pte); |
| 6319 | _dst_pte = pte_mkyoung(_dst_pte); |
| 6320 | |
| 6321 | if (wp_copy) |
| 6322 | _dst_pte = huge_pte_mkuffd_wp(_dst_pte); |
| 6323 | |
| 6324 | set_huge_pte_at(dst_mm, dst_addr, dst_pte, _dst_pte); |
| 6325 | |
| 6326 | hugetlb_count_add(pages_per_huge_page(h), dst_mm); |
| 6327 | |
| 6328 | /* No need to invalidate - it was non-present before */ |
| 6329 | update_mmu_cache(dst_vma, dst_addr, dst_pte); |
| 6330 | |
| 6331 | spin_unlock(ptl); |
| 6332 | if (!is_continue) |
| 6333 | SetHPageMigratable(page); |
| 6334 | if (vm_shared || is_continue) |
| 6335 | unlock_page(page); |
| 6336 | ret = 0; |
| 6337 | out: |
| 6338 | return ret; |
| 6339 | out_release_unlock: |
| 6340 | spin_unlock(ptl); |
| 6341 | if (vm_shared || is_continue) |
| 6342 | unlock_page(page); |
| 6343 | out_release_nounlock: |
| 6344 | if (!page_in_pagecache) |
| 6345 | restore_reserve_on_error(h, dst_vma, dst_addr, page); |
| 6346 | put_page(page); |
| 6347 | goto out; |
| 6348 | } |
| 6349 | #endif /* CONFIG_USERFAULTFD */ |
| 6350 | |
| 6351 | static void record_subpages_vmas(struct page *page, struct vm_area_struct *vma, |
| 6352 | int refs, struct page **pages, |
| 6353 | struct vm_area_struct **vmas) |
| 6354 | { |
| 6355 | int nr; |
| 6356 | |
| 6357 | for (nr = 0; nr < refs; nr++) { |
| 6358 | if (likely(pages)) |
| 6359 | pages[nr] = nth_page(page, nr); |
| 6360 | if (vmas) |
| 6361 | vmas[nr] = vma; |
| 6362 | } |
| 6363 | } |
| 6364 | |
| 6365 | static inline bool __follow_hugetlb_must_fault(struct vm_area_struct *vma, |
| 6366 | unsigned int flags, pte_t *pte, |
| 6367 | bool *unshare) |
| 6368 | { |
| 6369 | pte_t pteval = huge_ptep_get(pte); |
| 6370 | |
| 6371 | *unshare = false; |
| 6372 | if (is_swap_pte(pteval)) |
| 6373 | return true; |
| 6374 | if (huge_pte_write(pteval)) |
| 6375 | return false; |
| 6376 | if (flags & FOLL_WRITE) |
| 6377 | return true; |
| 6378 | if (gup_must_unshare(vma, flags, pte_page(pteval))) { |
| 6379 | *unshare = true; |
| 6380 | return true; |
| 6381 | } |
| 6382 | return false; |
| 6383 | } |
| 6384 | |
| 6385 | struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, |
| 6386 | unsigned long address, unsigned int flags) |
| 6387 | { |
| 6388 | struct hstate *h = hstate_vma(vma); |
| 6389 | struct mm_struct *mm = vma->vm_mm; |
| 6390 | unsigned long haddr = address & huge_page_mask(h); |
| 6391 | struct page *page = NULL; |
| 6392 | spinlock_t *ptl; |
| 6393 | pte_t *pte, entry; |
| 6394 | |
| 6395 | /* |
| 6396 | * FOLL_PIN is not supported for follow_page(). Ordinary GUP goes via |
| 6397 | * follow_hugetlb_page(). |
| 6398 | */ |
| 6399 | if (WARN_ON_ONCE(flags & FOLL_PIN)) |
| 6400 | return NULL; |
| 6401 | |
| 6402 | retry: |
| 6403 | pte = huge_pte_offset(mm, haddr, huge_page_size(h)); |
| 6404 | if (!pte) |
| 6405 | return NULL; |
| 6406 | |
| 6407 | ptl = huge_pte_lock(h, mm, pte); |
| 6408 | entry = huge_ptep_get(pte); |
| 6409 | if (pte_present(entry)) { |
| 6410 | page = pte_page(entry) + |
| 6411 | ((address & ~huge_page_mask(h)) >> PAGE_SHIFT); |
| 6412 | /* |
| 6413 | * Note that page may be a sub-page, and with vmemmap |
| 6414 | * optimizations the page struct may be read only. |
| 6415 | * try_grab_page() will increase the ref count on the |
| 6416 | * head page, so this will be OK. |
| 6417 | * |
| 6418 | * try_grab_page() should always be able to get the page here, |
| 6419 | * because we hold the ptl lock and have verified pte_present(). |
| 6420 | */ |
| 6421 | if (try_grab_page(page, flags)) { |
| 6422 | page = NULL; |
| 6423 | goto out; |
| 6424 | } |
| 6425 | } else { |
| 6426 | if (is_hugetlb_entry_migration(entry)) { |
| 6427 | spin_unlock(ptl); |
| 6428 | __migration_entry_wait_huge(pte, ptl); |
| 6429 | goto retry; |
| 6430 | } |
| 6431 | /* |
| 6432 | * hwpoisoned entry is treated as no_page_table in |
| 6433 | * follow_page_mask(). |
| 6434 | */ |
| 6435 | } |
| 6436 | out: |
| 6437 | spin_unlock(ptl); |
| 6438 | return page; |
| 6439 | } |
| 6440 | |
| 6441 | long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 6442 | struct page **pages, struct vm_area_struct **vmas, |
| 6443 | unsigned long *position, unsigned long *nr_pages, |
| 6444 | long i, unsigned int flags, int *locked) |
| 6445 | { |
| 6446 | unsigned long pfn_offset; |
| 6447 | unsigned long vaddr = *position; |
| 6448 | unsigned long remainder = *nr_pages; |
| 6449 | struct hstate *h = hstate_vma(vma); |
| 6450 | int err = -EFAULT, refs; |
| 6451 | |
| 6452 | while (vaddr < vma->vm_end && remainder) { |
| 6453 | pte_t *pte; |
| 6454 | spinlock_t *ptl = NULL; |
| 6455 | bool unshare = false; |
| 6456 | int absent; |
| 6457 | struct page *page; |
| 6458 | |
| 6459 | /* |
| 6460 | * If we have a pending SIGKILL, don't keep faulting pages and |
| 6461 | * potentially allocating memory. |
| 6462 | */ |
| 6463 | if (fatal_signal_pending(current)) { |
| 6464 | remainder = 0; |
| 6465 | break; |
| 6466 | } |
| 6467 | |
| 6468 | /* |
| 6469 | * Some archs (sparc64, sh*) have multiple pte_ts to |
| 6470 | * each hugepage. We have to make sure we get the |
| 6471 | * first, for the page indexing below to work. |
| 6472 | * |
| 6473 | * Note that page table lock is not held when pte is null. |
| 6474 | */ |
| 6475 | pte = huge_pte_offset(mm, vaddr & huge_page_mask(h), |
| 6476 | huge_page_size(h)); |
| 6477 | if (pte) |
| 6478 | ptl = huge_pte_lock(h, mm, pte); |
| 6479 | absent = !pte || huge_pte_none(huge_ptep_get(pte)); |
| 6480 | |
| 6481 | /* |
| 6482 | * When coredumping, it suits get_dump_page if we just return |
| 6483 | * an error where there's an empty slot with no huge pagecache |
| 6484 | * to back it. This way, we avoid allocating a hugepage, and |
| 6485 | * the sparse dumpfile avoids allocating disk blocks, but its |
| 6486 | * huge holes still show up with zeroes where they need to be. |
| 6487 | */ |
| 6488 | if (absent && (flags & FOLL_DUMP) && |
| 6489 | !hugetlbfs_pagecache_present(h, vma, vaddr)) { |
| 6490 | if (pte) |
| 6491 | spin_unlock(ptl); |
| 6492 | remainder = 0; |
| 6493 | break; |
| 6494 | } |
| 6495 | |
| 6496 | /* |
| 6497 | * We need call hugetlb_fault for both hugepages under migration |
| 6498 | * (in which case hugetlb_fault waits for the migration,) and |
| 6499 | * hwpoisoned hugepages (in which case we need to prevent the |
| 6500 | * caller from accessing to them.) In order to do this, we use |
| 6501 | * here is_swap_pte instead of is_hugetlb_entry_migration and |
| 6502 | * is_hugetlb_entry_hwpoisoned. This is because it simply covers |
| 6503 | * both cases, and because we can't follow correct pages |
| 6504 | * directly from any kind of swap entries. |
| 6505 | */ |
| 6506 | if (absent || |
| 6507 | __follow_hugetlb_must_fault(vma, flags, pte, &unshare)) { |
| 6508 | vm_fault_t ret; |
| 6509 | unsigned int fault_flags = 0; |
| 6510 | |
| 6511 | if (pte) |
| 6512 | spin_unlock(ptl); |
| 6513 | if (flags & FOLL_WRITE) |
| 6514 | fault_flags |= FAULT_FLAG_WRITE; |
| 6515 | else if (unshare) |
| 6516 | fault_flags |= FAULT_FLAG_UNSHARE; |
| 6517 | if (locked) { |
| 6518 | fault_flags |= FAULT_FLAG_ALLOW_RETRY | |
| 6519 | FAULT_FLAG_KILLABLE; |
| 6520 | if (flags & FOLL_INTERRUPTIBLE) |
| 6521 | fault_flags |= FAULT_FLAG_INTERRUPTIBLE; |
| 6522 | } |
| 6523 | if (flags & FOLL_NOWAIT) |
| 6524 | fault_flags |= FAULT_FLAG_ALLOW_RETRY | |
| 6525 | FAULT_FLAG_RETRY_NOWAIT; |
| 6526 | if (flags & FOLL_TRIED) { |
| 6527 | /* |
| 6528 | * Note: FAULT_FLAG_ALLOW_RETRY and |
| 6529 | * FAULT_FLAG_TRIED can co-exist |
| 6530 | */ |
| 6531 | fault_flags |= FAULT_FLAG_TRIED; |
| 6532 | } |
| 6533 | ret = hugetlb_fault(mm, vma, vaddr, fault_flags); |
| 6534 | if (ret & VM_FAULT_ERROR) { |
| 6535 | err = vm_fault_to_errno(ret, flags); |
| 6536 | remainder = 0; |
| 6537 | break; |
| 6538 | } |
| 6539 | if (ret & VM_FAULT_RETRY) { |
| 6540 | if (locked && |
| 6541 | !(fault_flags & FAULT_FLAG_RETRY_NOWAIT)) |
| 6542 | *locked = 0; |
| 6543 | *nr_pages = 0; |
| 6544 | /* |
| 6545 | * VM_FAULT_RETRY must not return an |
| 6546 | * error, it will return zero |
| 6547 | * instead. |
| 6548 | * |
| 6549 | * No need to update "position" as the |
| 6550 | * caller will not check it after |
| 6551 | * *nr_pages is set to 0. |
| 6552 | */ |
| 6553 | return i; |
| 6554 | } |
| 6555 | continue; |
| 6556 | } |
| 6557 | |
| 6558 | pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
| 6559 | page = pte_page(huge_ptep_get(pte)); |
| 6560 | |
| 6561 | VM_BUG_ON_PAGE((flags & FOLL_PIN) && PageAnon(page) && |
| 6562 | !PageAnonExclusive(page), page); |
| 6563 | |
| 6564 | /* |
| 6565 | * If subpage information not requested, update counters |
| 6566 | * and skip the same_page loop below. |
| 6567 | */ |
| 6568 | if (!pages && !vmas && !pfn_offset && |
| 6569 | (vaddr + huge_page_size(h) < vma->vm_end) && |
| 6570 | (remainder >= pages_per_huge_page(h))) { |
| 6571 | vaddr += huge_page_size(h); |
| 6572 | remainder -= pages_per_huge_page(h); |
| 6573 | i += pages_per_huge_page(h); |
| 6574 | spin_unlock(ptl); |
| 6575 | continue; |
| 6576 | } |
| 6577 | |
| 6578 | /* vaddr may not be aligned to PAGE_SIZE */ |
| 6579 | refs = min3(pages_per_huge_page(h) - pfn_offset, remainder, |
| 6580 | (vma->vm_end - ALIGN_DOWN(vaddr, PAGE_SIZE)) >> PAGE_SHIFT); |
| 6581 | |
| 6582 | if (pages || vmas) |
| 6583 | record_subpages_vmas(nth_page(page, pfn_offset), |
| 6584 | vma, refs, |
| 6585 | likely(pages) ? pages + i : NULL, |
| 6586 | vmas ? vmas + i : NULL); |
| 6587 | |
| 6588 | if (pages) { |
| 6589 | /* |
| 6590 | * try_grab_folio() should always succeed here, |
| 6591 | * because: a) we hold the ptl lock, and b) we've just |
| 6592 | * checked that the huge page is present in the page |
| 6593 | * tables. If the huge page is present, then the tail |
| 6594 | * pages must also be present. The ptl prevents the |
| 6595 | * head page and tail pages from being rearranged in |
| 6596 | * any way. As this is hugetlb, the pages will never |
| 6597 | * be p2pdma or not longterm pinable. So this page |
| 6598 | * must be available at this point, unless the page |
| 6599 | * refcount overflowed: |
| 6600 | */ |
| 6601 | if (WARN_ON_ONCE(!try_grab_folio(pages[i], refs, |
| 6602 | flags))) { |
| 6603 | spin_unlock(ptl); |
| 6604 | remainder = 0; |
| 6605 | err = -ENOMEM; |
| 6606 | break; |
| 6607 | } |
| 6608 | } |
| 6609 | |
| 6610 | vaddr += (refs << PAGE_SHIFT); |
| 6611 | remainder -= refs; |
| 6612 | i += refs; |
| 6613 | |
| 6614 | spin_unlock(ptl); |
| 6615 | } |
| 6616 | *nr_pages = remainder; |
| 6617 | /* |
| 6618 | * setting position is actually required only if remainder is |
| 6619 | * not zero but it's faster not to add a "if (remainder)" |
| 6620 | * branch. |
| 6621 | */ |
| 6622 | *position = vaddr; |
| 6623 | |
| 6624 | return i ? i : err; |
| 6625 | } |
| 6626 | |
| 6627 | unsigned long hugetlb_change_protection(struct vm_area_struct *vma, |
| 6628 | unsigned long address, unsigned long end, |
| 6629 | pgprot_t newprot, unsigned long cp_flags) |
| 6630 | { |
| 6631 | struct mm_struct *mm = vma->vm_mm; |
| 6632 | unsigned long start = address; |
| 6633 | pte_t *ptep; |
| 6634 | pte_t pte; |
| 6635 | struct hstate *h = hstate_vma(vma); |
| 6636 | unsigned long pages = 0, psize = huge_page_size(h); |
| 6637 | bool shared_pmd = false; |
| 6638 | struct mmu_notifier_range range; |
| 6639 | unsigned long last_addr_mask; |
| 6640 | bool uffd_wp = cp_flags & MM_CP_UFFD_WP; |
| 6641 | bool uffd_wp_resolve = cp_flags & MM_CP_UFFD_WP_RESOLVE; |
| 6642 | |
| 6643 | /* |
| 6644 | * In the case of shared PMDs, the area to flush could be beyond |
| 6645 | * start/end. Set range.start/range.end to cover the maximum possible |
| 6646 | * range if PMD sharing is possible. |
| 6647 | */ |
| 6648 | mmu_notifier_range_init(&range, MMU_NOTIFY_PROTECTION_VMA, |
| 6649 | 0, vma, mm, start, end); |
| 6650 | adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end); |
| 6651 | |
| 6652 | BUG_ON(address >= end); |
| 6653 | flush_cache_range(vma, range.start, range.end); |
| 6654 | |
| 6655 | mmu_notifier_invalidate_range_start(&range); |
| 6656 | hugetlb_vma_lock_write(vma); |
| 6657 | i_mmap_lock_write(vma->vm_file->f_mapping); |
| 6658 | last_addr_mask = hugetlb_mask_last_page(h); |
| 6659 | for (; address < end; address += psize) { |
| 6660 | spinlock_t *ptl; |
| 6661 | ptep = huge_pte_offset(mm, address, psize); |
| 6662 | if (!ptep) { |
| 6663 | if (!uffd_wp) { |
| 6664 | address |= last_addr_mask; |
| 6665 | continue; |
| 6666 | } |
| 6667 | /* |
| 6668 | * Userfaultfd wr-protect requires pgtable |
| 6669 | * pre-allocations to install pte markers. |
| 6670 | */ |
| 6671 | ptep = huge_pte_alloc(mm, vma, address, psize); |
| 6672 | if (!ptep) |
| 6673 | break; |
| 6674 | } |
| 6675 | ptl = huge_pte_lock(h, mm, ptep); |
| 6676 | if (huge_pmd_unshare(mm, vma, address, ptep)) { |
| 6677 | /* |
| 6678 | * When uffd-wp is enabled on the vma, unshare |
| 6679 | * shouldn't happen at all. Warn about it if it |
| 6680 | * happened due to some reason. |
| 6681 | */ |
| 6682 | WARN_ON_ONCE(uffd_wp || uffd_wp_resolve); |
| 6683 | pages++; |
| 6684 | spin_unlock(ptl); |
| 6685 | shared_pmd = true; |
| 6686 | address |= last_addr_mask; |
| 6687 | continue; |
| 6688 | } |
| 6689 | pte = huge_ptep_get(ptep); |
| 6690 | if (unlikely(is_hugetlb_entry_hwpoisoned(pte))) { |
| 6691 | /* Nothing to do. */ |
| 6692 | } else if (unlikely(is_hugetlb_entry_migration(pte))) { |
| 6693 | swp_entry_t entry = pte_to_swp_entry(pte); |
| 6694 | struct page *page = pfn_swap_entry_to_page(entry); |
| 6695 | pte_t newpte = pte; |
| 6696 | |
| 6697 | if (is_writable_migration_entry(entry)) { |
| 6698 | if (PageAnon(page)) |
| 6699 | entry = make_readable_exclusive_migration_entry( |
| 6700 | swp_offset(entry)); |
| 6701 | else |
| 6702 | entry = make_readable_migration_entry( |
| 6703 | swp_offset(entry)); |
| 6704 | newpte = swp_entry_to_pte(entry); |
| 6705 | pages++; |
| 6706 | } |
| 6707 | |
| 6708 | if (uffd_wp) |
| 6709 | newpte = pte_swp_mkuffd_wp(newpte); |
| 6710 | else if (uffd_wp_resolve) |
| 6711 | newpte = pte_swp_clear_uffd_wp(newpte); |
| 6712 | if (!pte_same(pte, newpte)) |
| 6713 | set_huge_pte_at(mm, address, ptep, newpte); |
| 6714 | } else if (unlikely(is_pte_marker(pte))) { |
| 6715 | /* No other markers apply for now. */ |
| 6716 | WARN_ON_ONCE(!pte_marker_uffd_wp(pte)); |
| 6717 | if (uffd_wp_resolve) |
| 6718 | /* Safe to modify directly (non-present->none). */ |
| 6719 | huge_pte_clear(mm, address, ptep, psize); |
| 6720 | } else if (!huge_pte_none(pte)) { |
| 6721 | pte_t old_pte; |
| 6722 | unsigned int shift = huge_page_shift(hstate_vma(vma)); |
| 6723 | |
| 6724 | old_pte = huge_ptep_modify_prot_start(vma, address, ptep); |
| 6725 | pte = huge_pte_modify(old_pte, newprot); |
| 6726 | pte = arch_make_huge_pte(pte, shift, vma->vm_flags); |
| 6727 | if (uffd_wp) |
| 6728 | pte = huge_pte_mkuffd_wp(huge_pte_wrprotect(pte)); |
| 6729 | else if (uffd_wp_resolve) |
| 6730 | pte = huge_pte_clear_uffd_wp(pte); |
| 6731 | huge_ptep_modify_prot_commit(vma, address, ptep, old_pte, pte); |
| 6732 | pages++; |
| 6733 | } else { |
| 6734 | /* None pte */ |
| 6735 | if (unlikely(uffd_wp)) |
| 6736 | /* Safe to modify directly (none->non-present). */ |
| 6737 | set_huge_pte_at(mm, address, ptep, |
| 6738 | make_pte_marker(PTE_MARKER_UFFD_WP)); |
| 6739 | } |
| 6740 | spin_unlock(ptl); |
| 6741 | } |
| 6742 | /* |
| 6743 | * Must flush TLB before releasing i_mmap_rwsem: x86's huge_pmd_unshare |
| 6744 | * may have cleared our pud entry and done put_page on the page table: |
| 6745 | * once we release i_mmap_rwsem, another task can do the final put_page |
| 6746 | * and that page table be reused and filled with junk. If we actually |
| 6747 | * did unshare a page of pmds, flush the range corresponding to the pud. |
| 6748 | */ |
| 6749 | if (shared_pmd) |
| 6750 | flush_hugetlb_tlb_range(vma, range.start, range.end); |
| 6751 | else |
| 6752 | flush_hugetlb_tlb_range(vma, start, end); |
| 6753 | /* |
| 6754 | * No need to call mmu_notifier_invalidate_range() we are downgrading |
| 6755 | * page table protection not changing it to point to a new page. |
| 6756 | * |
| 6757 | * See Documentation/mm/mmu_notifier.rst |
| 6758 | */ |
| 6759 | i_mmap_unlock_write(vma->vm_file->f_mapping); |
| 6760 | hugetlb_vma_unlock_write(vma); |
| 6761 | mmu_notifier_invalidate_range_end(&range); |
| 6762 | |
| 6763 | return pages << h->order; |
| 6764 | } |
| 6765 | |
| 6766 | /* Return true if reservation was successful, false otherwise. */ |
| 6767 | bool hugetlb_reserve_pages(struct inode *inode, |
| 6768 | long from, long to, |
| 6769 | struct vm_area_struct *vma, |
| 6770 | vm_flags_t vm_flags) |
| 6771 | { |
| 6772 | long chg, add = -1; |
| 6773 | struct hstate *h = hstate_inode(inode); |
| 6774 | struct hugepage_subpool *spool = subpool_inode(inode); |
| 6775 | struct resv_map *resv_map; |
| 6776 | struct hugetlb_cgroup *h_cg = NULL; |
| 6777 | long gbl_reserve, regions_needed = 0; |
| 6778 | |
| 6779 | /* This should never happen */ |
| 6780 | if (from > to) { |
| 6781 | VM_WARN(1, "%s called with a negative range\n", __func__); |
| 6782 | return false; |
| 6783 | } |
| 6784 | |
| 6785 | /* |
| 6786 | * vma specific semaphore used for pmd sharing and fault/truncation |
| 6787 | * synchronization |
| 6788 | */ |
| 6789 | hugetlb_vma_lock_alloc(vma); |
| 6790 | |
| 6791 | /* |
| 6792 | * Only apply hugepage reservation if asked. At fault time, an |
| 6793 | * attempt will be made for VM_NORESERVE to allocate a page |
| 6794 | * without using reserves |
| 6795 | */ |
| 6796 | if (vm_flags & VM_NORESERVE) |
| 6797 | return true; |
| 6798 | |
| 6799 | /* |
| 6800 | * Shared mappings base their reservation on the number of pages that |
| 6801 | * are already allocated on behalf of the file. Private mappings need |
| 6802 | * to reserve the full area even if read-only as mprotect() may be |
| 6803 | * called to make the mapping read-write. Assume !vma is a shm mapping |
| 6804 | */ |
| 6805 | if (!vma || vma->vm_flags & VM_MAYSHARE) { |
| 6806 | /* |
| 6807 | * resv_map can not be NULL as hugetlb_reserve_pages is only |
| 6808 | * called for inodes for which resv_maps were created (see |
| 6809 | * hugetlbfs_get_inode). |
| 6810 | */ |
| 6811 | resv_map = inode_resv_map(inode); |
| 6812 | |
| 6813 | chg = region_chg(resv_map, from, to, ®ions_needed); |
| 6814 | } else { |
| 6815 | /* Private mapping. */ |
| 6816 | resv_map = resv_map_alloc(); |
| 6817 | if (!resv_map) |
| 6818 | goto out_err; |
| 6819 | |
| 6820 | chg = to - from; |
| 6821 | |
| 6822 | set_vma_resv_map(vma, resv_map); |
| 6823 | set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
| 6824 | } |
| 6825 | |
| 6826 | if (chg < 0) |
| 6827 | goto out_err; |
| 6828 | |
| 6829 | if (hugetlb_cgroup_charge_cgroup_rsvd(hstate_index(h), |
| 6830 | chg * pages_per_huge_page(h), &h_cg) < 0) |
| 6831 | goto out_err; |
| 6832 | |
| 6833 | if (vma && !(vma->vm_flags & VM_MAYSHARE) && h_cg) { |
| 6834 | /* For private mappings, the hugetlb_cgroup uncharge info hangs |
| 6835 | * of the resv_map. |
| 6836 | */ |
| 6837 | resv_map_set_hugetlb_cgroup_uncharge_info(resv_map, h_cg, h); |
| 6838 | } |
| 6839 | |
| 6840 | /* |
| 6841 | * There must be enough pages in the subpool for the mapping. If |
| 6842 | * the subpool has a minimum size, there may be some global |
| 6843 | * reservations already in place (gbl_reserve). |
| 6844 | */ |
| 6845 | gbl_reserve = hugepage_subpool_get_pages(spool, chg); |
| 6846 | if (gbl_reserve < 0) |
| 6847 | goto out_uncharge_cgroup; |
| 6848 | |
| 6849 | /* |
| 6850 | * Check enough hugepages are available for the reservation. |
| 6851 | * Hand the pages back to the subpool if there are not |
| 6852 | */ |
| 6853 | if (hugetlb_acct_memory(h, gbl_reserve) < 0) |
| 6854 | goto out_put_pages; |
| 6855 | |
| 6856 | /* |
| 6857 | * Account for the reservations made. Shared mappings record regions |
| 6858 | * that have reservations as they are shared by multiple VMAs. |
| 6859 | * When the last VMA disappears, the region map says how much |
| 6860 | * the reservation was and the page cache tells how much of |
| 6861 | * the reservation was consumed. Private mappings are per-VMA and |
| 6862 | * only the consumed reservations are tracked. When the VMA |
| 6863 | * disappears, the original reservation is the VMA size and the |
| 6864 | * consumed reservations are stored in the map. Hence, nothing |
| 6865 | * else has to be done for private mappings here |
| 6866 | */ |
| 6867 | if (!vma || vma->vm_flags & VM_MAYSHARE) { |
| 6868 | add = region_add(resv_map, from, to, regions_needed, h, h_cg); |
| 6869 | |
| 6870 | if (unlikely(add < 0)) { |
| 6871 | hugetlb_acct_memory(h, -gbl_reserve); |
| 6872 | goto out_put_pages; |
| 6873 | } else if (unlikely(chg > add)) { |
| 6874 | /* |
| 6875 | * pages in this range were added to the reserve |
| 6876 | * map between region_chg and region_add. This |
| 6877 | * indicates a race with alloc_huge_page. Adjust |
| 6878 | * the subpool and reserve counts modified above |
| 6879 | * based on the difference. |
| 6880 | */ |
| 6881 | long rsv_adjust; |
| 6882 | |
| 6883 | /* |
| 6884 | * hugetlb_cgroup_uncharge_cgroup_rsvd() will put the |
| 6885 | * reference to h_cg->css. See comment below for detail. |
| 6886 | */ |
| 6887 | hugetlb_cgroup_uncharge_cgroup_rsvd( |
| 6888 | hstate_index(h), |
| 6889 | (chg - add) * pages_per_huge_page(h), h_cg); |
| 6890 | |
| 6891 | rsv_adjust = hugepage_subpool_put_pages(spool, |
| 6892 | chg - add); |
| 6893 | hugetlb_acct_memory(h, -rsv_adjust); |
| 6894 | } else if (h_cg) { |
| 6895 | /* |
| 6896 | * The file_regions will hold their own reference to |
| 6897 | * h_cg->css. So we should release the reference held |
| 6898 | * via hugetlb_cgroup_charge_cgroup_rsvd() when we are |
| 6899 | * done. |
| 6900 | */ |
| 6901 | hugetlb_cgroup_put_rsvd_cgroup(h_cg); |
| 6902 | } |
| 6903 | } |
| 6904 | return true; |
| 6905 | |
| 6906 | out_put_pages: |
| 6907 | /* put back original number of pages, chg */ |
| 6908 | (void)hugepage_subpool_put_pages(spool, chg); |
| 6909 | out_uncharge_cgroup: |
| 6910 | hugetlb_cgroup_uncharge_cgroup_rsvd(hstate_index(h), |
| 6911 | chg * pages_per_huge_page(h), h_cg); |
| 6912 | out_err: |
| 6913 | hugetlb_vma_lock_free(vma); |
| 6914 | if (!vma || vma->vm_flags & VM_MAYSHARE) |
| 6915 | /* Only call region_abort if the region_chg succeeded but the |
| 6916 | * region_add failed or didn't run. |
| 6917 | */ |
| 6918 | if (chg >= 0 && add < 0) |
| 6919 | region_abort(resv_map, from, to, regions_needed); |
| 6920 | if (vma && is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| 6921 | kref_put(&resv_map->refs, resv_map_release); |
| 6922 | return false; |
| 6923 | } |
| 6924 | |
| 6925 | long hugetlb_unreserve_pages(struct inode *inode, long start, long end, |
| 6926 | long freed) |
| 6927 | { |
| 6928 | struct hstate *h = hstate_inode(inode); |
| 6929 | struct resv_map *resv_map = inode_resv_map(inode); |
| 6930 | long chg = 0; |
| 6931 | struct hugepage_subpool *spool = subpool_inode(inode); |
| 6932 | long gbl_reserve; |
| 6933 | |
| 6934 | /* |
| 6935 | * Since this routine can be called in the evict inode path for all |
| 6936 | * hugetlbfs inodes, resv_map could be NULL. |
| 6937 | */ |
| 6938 | if (resv_map) { |
| 6939 | chg = region_del(resv_map, start, end); |
| 6940 | /* |
| 6941 | * region_del() can fail in the rare case where a region |
| 6942 | * must be split and another region descriptor can not be |
| 6943 | * allocated. If end == LONG_MAX, it will not fail. |
| 6944 | */ |
| 6945 | if (chg < 0) |
| 6946 | return chg; |
| 6947 | } |
| 6948 | |
| 6949 | spin_lock(&inode->i_lock); |
| 6950 | inode->i_blocks -= (blocks_per_huge_page(h) * freed); |
| 6951 | spin_unlock(&inode->i_lock); |
| 6952 | |
| 6953 | /* |
| 6954 | * If the subpool has a minimum size, the number of global |
| 6955 | * reservations to be released may be adjusted. |
| 6956 | * |
| 6957 | * Note that !resv_map implies freed == 0. So (chg - freed) |
| 6958 | * won't go negative. |
| 6959 | */ |
| 6960 | gbl_reserve = hugepage_subpool_put_pages(spool, (chg - freed)); |
| 6961 | hugetlb_acct_memory(h, -gbl_reserve); |
| 6962 | |
| 6963 | return 0; |
| 6964 | } |
| 6965 | |
| 6966 | #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE |
| 6967 | static unsigned long page_table_shareable(struct vm_area_struct *svma, |
| 6968 | struct vm_area_struct *vma, |
| 6969 | unsigned long addr, pgoff_t idx) |
| 6970 | { |
| 6971 | unsigned long saddr = ((idx - svma->vm_pgoff) << PAGE_SHIFT) + |
| 6972 | svma->vm_start; |
| 6973 | unsigned long sbase = saddr & PUD_MASK; |
| 6974 | unsigned long s_end = sbase + PUD_SIZE; |
| 6975 | |
| 6976 | /* Allow segments to share if only one is marked locked */ |
| 6977 | unsigned long vm_flags = vma->vm_flags & VM_LOCKED_CLEAR_MASK; |
| 6978 | unsigned long svm_flags = svma->vm_flags & VM_LOCKED_CLEAR_MASK; |
| 6979 | |
| 6980 | /* |
| 6981 | * match the virtual addresses, permission and the alignment of the |
| 6982 | * page table page. |
| 6983 | * |
| 6984 | * Also, vma_lock (vm_private_data) is required for sharing. |
| 6985 | */ |
| 6986 | if (pmd_index(addr) != pmd_index(saddr) || |
| 6987 | vm_flags != svm_flags || |
| 6988 | !range_in_vma(svma, sbase, s_end) || |
| 6989 | !svma->vm_private_data) |
| 6990 | return 0; |
| 6991 | |
| 6992 | return saddr; |
| 6993 | } |
| 6994 | |
| 6995 | bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) |
| 6996 | { |
| 6997 | unsigned long start = addr & PUD_MASK; |
| 6998 | unsigned long end = start + PUD_SIZE; |
| 6999 | |
| 7000 | #ifdef CONFIG_USERFAULTFD |
| 7001 | if (uffd_disable_huge_pmd_share(vma)) |
| 7002 | return false; |
| 7003 | #endif |
| 7004 | /* |
| 7005 | * check on proper vm_flags and page table alignment |
| 7006 | */ |
| 7007 | if (!(vma->vm_flags & VM_MAYSHARE)) |
| 7008 | return false; |
| 7009 | if (!vma->vm_private_data) /* vma lock required for sharing */ |
| 7010 | return false; |
| 7011 | if (!range_in_vma(vma, start, end)) |
| 7012 | return false; |
| 7013 | return true; |
| 7014 | } |
| 7015 | |
| 7016 | /* |
| 7017 | * Determine if start,end range within vma could be mapped by shared pmd. |
| 7018 | * If yes, adjust start and end to cover range associated with possible |
| 7019 | * shared pmd mappings. |
| 7020 | */ |
| 7021 | void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, |
| 7022 | unsigned long *start, unsigned long *end) |
| 7023 | { |
| 7024 | unsigned long v_start = ALIGN(vma->vm_start, PUD_SIZE), |
| 7025 | v_end = ALIGN_DOWN(vma->vm_end, PUD_SIZE); |
| 7026 | |
| 7027 | /* |
| 7028 | * vma needs to span at least one aligned PUD size, and the range |
| 7029 | * must be at least partially within in. |
| 7030 | */ |
| 7031 | if (!(vma->vm_flags & VM_MAYSHARE) || !(v_end > v_start) || |
| 7032 | (*end <= v_start) || (*start >= v_end)) |
| 7033 | return; |
| 7034 | |
| 7035 | /* Extend the range to be PUD aligned for a worst case scenario */ |
| 7036 | if (*start > v_start) |
| 7037 | *start = ALIGN_DOWN(*start, PUD_SIZE); |
| 7038 | |
| 7039 | if (*end < v_end) |
| 7040 | *end = ALIGN(*end, PUD_SIZE); |
| 7041 | } |
| 7042 | |
| 7043 | /* |
| 7044 | * Search for a shareable pmd page for hugetlb. In any case calls pmd_alloc() |
| 7045 | * and returns the corresponding pte. While this is not necessary for the |
| 7046 | * !shared pmd case because we can allocate the pmd later as well, it makes the |
| 7047 | * code much cleaner. pmd allocation is essential for the shared case because |
| 7048 | * pud has to be populated inside the same i_mmap_rwsem section - otherwise |
| 7049 | * racing tasks could either miss the sharing (see huge_pte_offset) or select a |
| 7050 | * bad pmd for sharing. |
| 7051 | */ |
| 7052 | pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, |
| 7053 | unsigned long addr, pud_t *pud) |
| 7054 | { |
| 7055 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 7056 | pgoff_t idx = ((addr - vma->vm_start) >> PAGE_SHIFT) + |
| 7057 | vma->vm_pgoff; |
| 7058 | struct vm_area_struct *svma; |
| 7059 | unsigned long saddr; |
| 7060 | pte_t *spte = NULL; |
| 7061 | pte_t *pte; |
| 7062 | spinlock_t *ptl; |
| 7063 | |
| 7064 | i_mmap_lock_read(mapping); |
| 7065 | vma_interval_tree_foreach(svma, &mapping->i_mmap, idx, idx) { |
| 7066 | if (svma == vma) |
| 7067 | continue; |
| 7068 | |
| 7069 | saddr = page_table_shareable(svma, vma, addr, idx); |
| 7070 | if (saddr) { |
| 7071 | spte = huge_pte_offset(svma->vm_mm, saddr, |
| 7072 | vma_mmu_pagesize(svma)); |
| 7073 | if (spte) { |
| 7074 | get_page(virt_to_page(spte)); |
| 7075 | break; |
| 7076 | } |
| 7077 | } |
| 7078 | } |
| 7079 | |
| 7080 | if (!spte) |
| 7081 | goto out; |
| 7082 | |
| 7083 | ptl = huge_pte_lock(hstate_vma(vma), mm, spte); |
| 7084 | if (pud_none(*pud)) { |
| 7085 | pud_populate(mm, pud, |
| 7086 | (pmd_t *)((unsigned long)spte & PAGE_MASK)); |
| 7087 | mm_inc_nr_pmds(mm); |
| 7088 | } else { |
| 7089 | put_page(virt_to_page(spte)); |
| 7090 | } |
| 7091 | spin_unlock(ptl); |
| 7092 | out: |
| 7093 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
| 7094 | i_mmap_unlock_read(mapping); |
| 7095 | return pte; |
| 7096 | } |
| 7097 | |
| 7098 | /* |
| 7099 | * unmap huge page backed by shared pte. |
| 7100 | * |
| 7101 | * Hugetlb pte page is ref counted at the time of mapping. If pte is shared |
| 7102 | * indicated by page_count > 1, unmap is achieved by clearing pud and |
| 7103 | * decrementing the ref count. If count == 1, the pte page is not shared. |
| 7104 | * |
| 7105 | * Called with page table lock held. |
| 7106 | * |
| 7107 | * returns: 1 successfully unmapped a shared pte page |
| 7108 | * 0 the underlying pte page is not shared, or it is the last user |
| 7109 | */ |
| 7110 | int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, |
| 7111 | unsigned long addr, pte_t *ptep) |
| 7112 | { |
| 7113 | pgd_t *pgd = pgd_offset(mm, addr); |
| 7114 | p4d_t *p4d = p4d_offset(pgd, addr); |
| 7115 | pud_t *pud = pud_offset(p4d, addr); |
| 7116 | |
| 7117 | i_mmap_assert_write_locked(vma->vm_file->f_mapping); |
| 7118 | hugetlb_vma_assert_locked(vma); |
| 7119 | BUG_ON(page_count(virt_to_page(ptep)) == 0); |
| 7120 | if (page_count(virt_to_page(ptep)) == 1) |
| 7121 | return 0; |
| 7122 | |
| 7123 | pud_clear(pud); |
| 7124 | put_page(virt_to_page(ptep)); |
| 7125 | mm_dec_nr_pmds(mm); |
| 7126 | return 1; |
| 7127 | } |
| 7128 | |
| 7129 | #else /* !CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
| 7130 | |
| 7131 | pte_t *huge_pmd_share(struct mm_struct *mm, struct vm_area_struct *vma, |
| 7132 | unsigned long addr, pud_t *pud) |
| 7133 | { |
| 7134 | return NULL; |
| 7135 | } |
| 7136 | |
| 7137 | int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, |
| 7138 | unsigned long addr, pte_t *ptep) |
| 7139 | { |
| 7140 | return 0; |
| 7141 | } |
| 7142 | |
| 7143 | void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, |
| 7144 | unsigned long *start, unsigned long *end) |
| 7145 | { |
| 7146 | } |
| 7147 | |
| 7148 | bool want_pmd_share(struct vm_area_struct *vma, unsigned long addr) |
| 7149 | { |
| 7150 | return false; |
| 7151 | } |
| 7152 | #endif /* CONFIG_ARCH_WANT_HUGE_PMD_SHARE */ |
| 7153 | |
| 7154 | #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB |
| 7155 | pte_t *huge_pte_alloc(struct mm_struct *mm, struct vm_area_struct *vma, |
| 7156 | unsigned long addr, unsigned long sz) |
| 7157 | { |
| 7158 | pgd_t *pgd; |
| 7159 | p4d_t *p4d; |
| 7160 | pud_t *pud; |
| 7161 | pte_t *pte = NULL; |
| 7162 | |
| 7163 | pgd = pgd_offset(mm, addr); |
| 7164 | p4d = p4d_alloc(mm, pgd, addr); |
| 7165 | if (!p4d) |
| 7166 | return NULL; |
| 7167 | pud = pud_alloc(mm, p4d, addr); |
| 7168 | if (pud) { |
| 7169 | if (sz == PUD_SIZE) { |
| 7170 | pte = (pte_t *)pud; |
| 7171 | } else { |
| 7172 | BUG_ON(sz != PMD_SIZE); |
| 7173 | if (want_pmd_share(vma, addr) && pud_none(*pud)) |
| 7174 | pte = huge_pmd_share(mm, vma, addr, pud); |
| 7175 | else |
| 7176 | pte = (pte_t *)pmd_alloc(mm, pud, addr); |
| 7177 | } |
| 7178 | } |
| 7179 | BUG_ON(pte && pte_present(*pte) && !pte_huge(*pte)); |
| 7180 | |
| 7181 | return pte; |
| 7182 | } |
| 7183 | |
| 7184 | /* |
| 7185 | * huge_pte_offset() - Walk the page table to resolve the hugepage |
| 7186 | * entry at address @addr |
| 7187 | * |
| 7188 | * Return: Pointer to page table entry (PUD or PMD) for |
| 7189 | * address @addr, or NULL if a !p*d_present() entry is encountered and the |
| 7190 | * size @sz doesn't match the hugepage size at this level of the page |
| 7191 | * table. |
| 7192 | */ |
| 7193 | pte_t *huge_pte_offset(struct mm_struct *mm, |
| 7194 | unsigned long addr, unsigned long sz) |
| 7195 | { |
| 7196 | pgd_t *pgd; |
| 7197 | p4d_t *p4d; |
| 7198 | pud_t *pud; |
| 7199 | pmd_t *pmd; |
| 7200 | |
| 7201 | pgd = pgd_offset(mm, addr); |
| 7202 | if (!pgd_present(*pgd)) |
| 7203 | return NULL; |
| 7204 | p4d = p4d_offset(pgd, addr); |
| 7205 | if (!p4d_present(*p4d)) |
| 7206 | return NULL; |
| 7207 | |
| 7208 | pud = pud_offset(p4d, addr); |
| 7209 | if (sz == PUD_SIZE) |
| 7210 | /* must be pud huge, non-present or none */ |
| 7211 | return (pte_t *)pud; |
| 7212 | if (!pud_present(*pud)) |
| 7213 | return NULL; |
| 7214 | /* must have a valid entry and size to go further */ |
| 7215 | |
| 7216 | pmd = pmd_offset(pud, addr); |
| 7217 | /* must be pmd huge, non-present or none */ |
| 7218 | return (pte_t *)pmd; |
| 7219 | } |
| 7220 | |
| 7221 | /* |
| 7222 | * Return a mask that can be used to update an address to the last huge |
| 7223 | * page in a page table page mapping size. Used to skip non-present |
| 7224 | * page table entries when linearly scanning address ranges. Architectures |
| 7225 | * with unique huge page to page table relationships can define their own |
| 7226 | * version of this routine. |
| 7227 | */ |
| 7228 | unsigned long hugetlb_mask_last_page(struct hstate *h) |
| 7229 | { |
| 7230 | unsigned long hp_size = huge_page_size(h); |
| 7231 | |
| 7232 | if (hp_size == PUD_SIZE) |
| 7233 | return P4D_SIZE - PUD_SIZE; |
| 7234 | else if (hp_size == PMD_SIZE) |
| 7235 | return PUD_SIZE - PMD_SIZE; |
| 7236 | else |
| 7237 | return 0UL; |
| 7238 | } |
| 7239 | |
| 7240 | #else |
| 7241 | |
| 7242 | /* See description above. Architectures can provide their own version. */ |
| 7243 | __weak unsigned long hugetlb_mask_last_page(struct hstate *h) |
| 7244 | { |
| 7245 | #ifdef CONFIG_ARCH_WANT_HUGE_PMD_SHARE |
| 7246 | if (huge_page_size(h) == PMD_SIZE) |
| 7247 | return PUD_SIZE - PMD_SIZE; |
| 7248 | #endif |
| 7249 | return 0UL; |
| 7250 | } |
| 7251 | |
| 7252 | #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */ |
| 7253 | |
| 7254 | /* |
| 7255 | * These functions are overwritable if your architecture needs its own |
| 7256 | * behavior. |
| 7257 | */ |
| 7258 | int isolate_hugetlb(struct page *page, struct list_head *list) |
| 7259 | { |
| 7260 | int ret = 0; |
| 7261 | |
| 7262 | spin_lock_irq(&hugetlb_lock); |
| 7263 | if (!PageHeadHuge(page) || |
| 7264 | !HPageMigratable(page) || |
| 7265 | !get_page_unless_zero(page)) { |
| 7266 | ret = -EBUSY; |
| 7267 | goto unlock; |
| 7268 | } |
| 7269 | ClearHPageMigratable(page); |
| 7270 | list_move_tail(&page->lru, list); |
| 7271 | unlock: |
| 7272 | spin_unlock_irq(&hugetlb_lock); |
| 7273 | return ret; |
| 7274 | } |
| 7275 | |
| 7276 | int get_hwpoison_huge_page(struct page *page, bool *hugetlb, bool unpoison) |
| 7277 | { |
| 7278 | int ret = 0; |
| 7279 | |
| 7280 | *hugetlb = false; |
| 7281 | spin_lock_irq(&hugetlb_lock); |
| 7282 | if (PageHeadHuge(page)) { |
| 7283 | *hugetlb = true; |
| 7284 | if (HPageFreed(page)) |
| 7285 | ret = 0; |
| 7286 | else if (HPageMigratable(page) || unpoison) |
| 7287 | ret = get_page_unless_zero(page); |
| 7288 | else |
| 7289 | ret = -EBUSY; |
| 7290 | } |
| 7291 | spin_unlock_irq(&hugetlb_lock); |
| 7292 | return ret; |
| 7293 | } |
| 7294 | |
| 7295 | int get_huge_page_for_hwpoison(unsigned long pfn, int flags, |
| 7296 | bool *migratable_cleared) |
| 7297 | { |
| 7298 | int ret; |
| 7299 | |
| 7300 | spin_lock_irq(&hugetlb_lock); |
| 7301 | ret = __get_huge_page_for_hwpoison(pfn, flags, migratable_cleared); |
| 7302 | spin_unlock_irq(&hugetlb_lock); |
| 7303 | return ret; |
| 7304 | } |
| 7305 | |
| 7306 | void putback_active_hugepage(struct page *page) |
| 7307 | { |
| 7308 | spin_lock_irq(&hugetlb_lock); |
| 7309 | SetHPageMigratable(page); |
| 7310 | list_move_tail(&page->lru, &(page_hstate(page))->hugepage_activelist); |
| 7311 | spin_unlock_irq(&hugetlb_lock); |
| 7312 | put_page(page); |
| 7313 | } |
| 7314 | |
| 7315 | void move_hugetlb_state(struct folio *old_folio, struct folio *new_folio, int reason) |
| 7316 | { |
| 7317 | struct hstate *h = folio_hstate(old_folio); |
| 7318 | |
| 7319 | hugetlb_cgroup_migrate(old_folio, new_folio); |
| 7320 | set_page_owner_migrate_reason(&new_folio->page, reason); |
| 7321 | |
| 7322 | /* |
| 7323 | * transfer temporary state of the new hugetlb folio. This is |
| 7324 | * reverse to other transitions because the newpage is going to |
| 7325 | * be final while the old one will be freed so it takes over |
| 7326 | * the temporary status. |
| 7327 | * |
| 7328 | * Also note that we have to transfer the per-node surplus state |
| 7329 | * here as well otherwise the global surplus count will not match |
| 7330 | * the per-node's. |
| 7331 | */ |
| 7332 | if (folio_test_hugetlb_temporary(new_folio)) { |
| 7333 | int old_nid = folio_nid(old_folio); |
| 7334 | int new_nid = folio_nid(new_folio); |
| 7335 | |
| 7336 | folio_set_hugetlb_temporary(old_folio); |
| 7337 | folio_clear_hugetlb_temporary(new_folio); |
| 7338 | |
| 7339 | |
| 7340 | /* |
| 7341 | * There is no need to transfer the per-node surplus state |
| 7342 | * when we do not cross the node. |
| 7343 | */ |
| 7344 | if (new_nid == old_nid) |
| 7345 | return; |
| 7346 | spin_lock_irq(&hugetlb_lock); |
| 7347 | if (h->surplus_huge_pages_node[old_nid]) { |
| 7348 | h->surplus_huge_pages_node[old_nid]--; |
| 7349 | h->surplus_huge_pages_node[new_nid]++; |
| 7350 | } |
| 7351 | spin_unlock_irq(&hugetlb_lock); |
| 7352 | } |
| 7353 | } |
| 7354 | |
| 7355 | static void hugetlb_unshare_pmds(struct vm_area_struct *vma, |
| 7356 | unsigned long start, |
| 7357 | unsigned long end) |
| 7358 | { |
| 7359 | struct hstate *h = hstate_vma(vma); |
| 7360 | unsigned long sz = huge_page_size(h); |
| 7361 | struct mm_struct *mm = vma->vm_mm; |
| 7362 | struct mmu_notifier_range range; |
| 7363 | unsigned long address; |
| 7364 | spinlock_t *ptl; |
| 7365 | pte_t *ptep; |
| 7366 | |
| 7367 | if (!(vma->vm_flags & VM_MAYSHARE)) |
| 7368 | return; |
| 7369 | |
| 7370 | if (start >= end) |
| 7371 | return; |
| 7372 | |
| 7373 | flush_cache_range(vma, start, end); |
| 7374 | /* |
| 7375 | * No need to call adjust_range_if_pmd_sharing_possible(), because |
| 7376 | * we have already done the PUD_SIZE alignment. |
| 7377 | */ |
| 7378 | mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, mm, |
| 7379 | start, end); |
| 7380 | mmu_notifier_invalidate_range_start(&range); |
| 7381 | hugetlb_vma_lock_write(vma); |
| 7382 | i_mmap_lock_write(vma->vm_file->f_mapping); |
| 7383 | for (address = start; address < end; address += PUD_SIZE) { |
| 7384 | ptep = huge_pte_offset(mm, address, sz); |
| 7385 | if (!ptep) |
| 7386 | continue; |
| 7387 | ptl = huge_pte_lock(h, mm, ptep); |
| 7388 | huge_pmd_unshare(mm, vma, address, ptep); |
| 7389 | spin_unlock(ptl); |
| 7390 | } |
| 7391 | flush_hugetlb_tlb_range(vma, start, end); |
| 7392 | i_mmap_unlock_write(vma->vm_file->f_mapping); |
| 7393 | hugetlb_vma_unlock_write(vma); |
| 7394 | /* |
| 7395 | * No need to call mmu_notifier_invalidate_range(), see |
| 7396 | * Documentation/mm/mmu_notifier.rst. |
| 7397 | */ |
| 7398 | mmu_notifier_invalidate_range_end(&range); |
| 7399 | } |
| 7400 | |
| 7401 | /* |
| 7402 | * This function will unconditionally remove all the shared pmd pgtable entries |
| 7403 | * within the specific vma for a hugetlbfs memory range. |
| 7404 | */ |
| 7405 | void hugetlb_unshare_all_pmds(struct vm_area_struct *vma) |
| 7406 | { |
| 7407 | hugetlb_unshare_pmds(vma, ALIGN(vma->vm_start, PUD_SIZE), |
| 7408 | ALIGN_DOWN(vma->vm_end, PUD_SIZE)); |
| 7409 | } |
| 7410 | |
| 7411 | #ifdef CONFIG_CMA |
| 7412 | static bool cma_reserve_called __initdata; |
| 7413 | |
| 7414 | static int __init cmdline_parse_hugetlb_cma(char *p) |
| 7415 | { |
| 7416 | int nid, count = 0; |
| 7417 | unsigned long tmp; |
| 7418 | char *s = p; |
| 7419 | |
| 7420 | while (*s) { |
| 7421 | if (sscanf(s, "%lu%n", &tmp, &count) != 1) |
| 7422 | break; |
| 7423 | |
| 7424 | if (s[count] == ':') { |
| 7425 | if (tmp >= MAX_NUMNODES) |
| 7426 | break; |
| 7427 | nid = array_index_nospec(tmp, MAX_NUMNODES); |
| 7428 | |
| 7429 | s += count + 1; |
| 7430 | tmp = memparse(s, &s); |
| 7431 | hugetlb_cma_size_in_node[nid] = tmp; |
| 7432 | hugetlb_cma_size += tmp; |
| 7433 | |
| 7434 | /* |
| 7435 | * Skip the separator if have one, otherwise |
| 7436 | * break the parsing. |
| 7437 | */ |
| 7438 | if (*s == ',') |
| 7439 | s++; |
| 7440 | else |
| 7441 | break; |
| 7442 | } else { |
| 7443 | hugetlb_cma_size = memparse(p, &p); |
| 7444 | break; |
| 7445 | } |
| 7446 | } |
| 7447 | |
| 7448 | return 0; |
| 7449 | } |
| 7450 | |
| 7451 | early_param("hugetlb_cma", cmdline_parse_hugetlb_cma); |
| 7452 | |
| 7453 | void __init hugetlb_cma_reserve(int order) |
| 7454 | { |
| 7455 | unsigned long size, reserved, per_node; |
| 7456 | bool node_specific_cma_alloc = false; |
| 7457 | int nid; |
| 7458 | |
| 7459 | cma_reserve_called = true; |
| 7460 | |
| 7461 | if (!hugetlb_cma_size) |
| 7462 | return; |
| 7463 | |
| 7464 | for (nid = 0; nid < MAX_NUMNODES; nid++) { |
| 7465 | if (hugetlb_cma_size_in_node[nid] == 0) |
| 7466 | continue; |
| 7467 | |
| 7468 | if (!node_online(nid)) { |
| 7469 | pr_warn("hugetlb_cma: invalid node %d specified\n", nid); |
| 7470 | hugetlb_cma_size -= hugetlb_cma_size_in_node[nid]; |
| 7471 | hugetlb_cma_size_in_node[nid] = 0; |
| 7472 | continue; |
| 7473 | } |
| 7474 | |
| 7475 | if (hugetlb_cma_size_in_node[nid] < (PAGE_SIZE << order)) { |
| 7476 | pr_warn("hugetlb_cma: cma area of node %d should be at least %lu MiB\n", |
| 7477 | nid, (PAGE_SIZE << order) / SZ_1M); |
| 7478 | hugetlb_cma_size -= hugetlb_cma_size_in_node[nid]; |
| 7479 | hugetlb_cma_size_in_node[nid] = 0; |
| 7480 | } else { |
| 7481 | node_specific_cma_alloc = true; |
| 7482 | } |
| 7483 | } |
| 7484 | |
| 7485 | /* Validate the CMA size again in case some invalid nodes specified. */ |
| 7486 | if (!hugetlb_cma_size) |
| 7487 | return; |
| 7488 | |
| 7489 | if (hugetlb_cma_size < (PAGE_SIZE << order)) { |
| 7490 | pr_warn("hugetlb_cma: cma area should be at least %lu MiB\n", |
| 7491 | (PAGE_SIZE << order) / SZ_1M); |
| 7492 | hugetlb_cma_size = 0; |
| 7493 | return; |
| 7494 | } |
| 7495 | |
| 7496 | if (!node_specific_cma_alloc) { |
| 7497 | /* |
| 7498 | * If 3 GB area is requested on a machine with 4 numa nodes, |
| 7499 | * let's allocate 1 GB on first three nodes and ignore the last one. |
| 7500 | */ |
| 7501 | per_node = DIV_ROUND_UP(hugetlb_cma_size, nr_online_nodes); |
| 7502 | pr_info("hugetlb_cma: reserve %lu MiB, up to %lu MiB per node\n", |
| 7503 | hugetlb_cma_size / SZ_1M, per_node / SZ_1M); |
| 7504 | } |
| 7505 | |
| 7506 | reserved = 0; |
| 7507 | for_each_online_node(nid) { |
| 7508 | int res; |
| 7509 | char name[CMA_MAX_NAME]; |
| 7510 | |
| 7511 | if (node_specific_cma_alloc) { |
| 7512 | if (hugetlb_cma_size_in_node[nid] == 0) |
| 7513 | continue; |
| 7514 | |
| 7515 | size = hugetlb_cma_size_in_node[nid]; |
| 7516 | } else { |
| 7517 | size = min(per_node, hugetlb_cma_size - reserved); |
| 7518 | } |
| 7519 | |
| 7520 | size = round_up(size, PAGE_SIZE << order); |
| 7521 | |
| 7522 | snprintf(name, sizeof(name), "hugetlb%d", nid); |
| 7523 | /* |
| 7524 | * Note that 'order per bit' is based on smallest size that |
| 7525 | * may be returned to CMA allocator in the case of |
| 7526 | * huge page demotion. |
| 7527 | */ |
| 7528 | res = cma_declare_contiguous_nid(0, size, 0, |
| 7529 | PAGE_SIZE << HUGETLB_PAGE_ORDER, |
| 7530 | 0, false, name, |
| 7531 | &hugetlb_cma[nid], nid); |
| 7532 | if (res) { |
| 7533 | pr_warn("hugetlb_cma: reservation failed: err %d, node %d", |
| 7534 | res, nid); |
| 7535 | continue; |
| 7536 | } |
| 7537 | |
| 7538 | reserved += size; |
| 7539 | pr_info("hugetlb_cma: reserved %lu MiB on node %d\n", |
| 7540 | size / SZ_1M, nid); |
| 7541 | |
| 7542 | if (reserved >= hugetlb_cma_size) |
| 7543 | break; |
| 7544 | } |
| 7545 | |
| 7546 | if (!reserved) |
| 7547 | /* |
| 7548 | * hugetlb_cma_size is used to determine if allocations from |
| 7549 | * cma are possible. Set to zero if no cma regions are set up. |
| 7550 | */ |
| 7551 | hugetlb_cma_size = 0; |
| 7552 | } |
| 7553 | |
| 7554 | static void __init hugetlb_cma_check(void) |
| 7555 | { |
| 7556 | if (!hugetlb_cma_size || cma_reserve_called) |
| 7557 | return; |
| 7558 | |
| 7559 | pr_warn("hugetlb_cma: the option isn't supported by current arch\n"); |
| 7560 | } |
| 7561 | |
| 7562 | #endif /* CONFIG_CMA */ |