| 1 | /* |
| 2 | * Generic hugetlb support. |
| 3 | * (C) William Irwin, April 2004 |
| 4 | */ |
| 5 | #include <linux/gfp.h> |
| 6 | #include <linux/list.h> |
| 7 | #include <linux/init.h> |
| 8 | #include <linux/module.h> |
| 9 | #include <linux/mm.h> |
| 10 | #include <linux/sysctl.h> |
| 11 | #include <linux/highmem.h> |
| 12 | #include <linux/nodemask.h> |
| 13 | #include <linux/pagemap.h> |
| 14 | #include <linux/mempolicy.h> |
| 15 | #include <linux/cpuset.h> |
| 16 | #include <linux/mutex.h> |
| 17 | |
| 18 | #include <asm/page.h> |
| 19 | #include <asm/pgtable.h> |
| 20 | |
| 21 | #include <linux/hugetlb.h> |
| 22 | #include "internal.h" |
| 23 | |
| 24 | const unsigned long hugetlb_zero = 0, hugetlb_infinity = ~0UL; |
| 25 | static gfp_t htlb_alloc_mask = GFP_HIGHUSER; |
| 26 | unsigned long hugepages_treat_as_movable; |
| 27 | |
| 28 | static int max_hstate; |
| 29 | unsigned int default_hstate_idx; |
| 30 | struct hstate hstates[HUGE_MAX_HSTATE]; |
| 31 | |
| 32 | /* for command line parsing */ |
| 33 | static struct hstate * __initdata parsed_hstate; |
| 34 | static unsigned long __initdata default_hstate_max_huge_pages; |
| 35 | |
| 36 | #define for_each_hstate(h) \ |
| 37 | for ((h) = hstates; (h) < &hstates[max_hstate]; (h)++) |
| 38 | |
| 39 | /* |
| 40 | * Protects updates to hugepage_freelists, nr_huge_pages, and free_huge_pages |
| 41 | */ |
| 42 | static DEFINE_SPINLOCK(hugetlb_lock); |
| 43 | |
| 44 | /* |
| 45 | * Region tracking -- allows tracking of reservations and instantiated pages |
| 46 | * across the pages in a mapping. |
| 47 | * |
| 48 | * The region data structures are protected by a combination of the mmap_sem |
| 49 | * and the hugetlb_instantion_mutex. To access or modify a region the caller |
| 50 | * must either hold the mmap_sem for write, or the mmap_sem for read and |
| 51 | * the hugetlb_instantiation mutex: |
| 52 | * |
| 53 | * down_write(&mm->mmap_sem); |
| 54 | * or |
| 55 | * down_read(&mm->mmap_sem); |
| 56 | * mutex_lock(&hugetlb_instantiation_mutex); |
| 57 | */ |
| 58 | struct file_region { |
| 59 | struct list_head link; |
| 60 | long from; |
| 61 | long to; |
| 62 | }; |
| 63 | |
| 64 | static long region_add(struct list_head *head, long f, long t) |
| 65 | { |
| 66 | struct file_region *rg, *nrg, *trg; |
| 67 | |
| 68 | /* Locate the region we are either in or before. */ |
| 69 | list_for_each_entry(rg, head, link) |
| 70 | if (f <= rg->to) |
| 71 | break; |
| 72 | |
| 73 | /* Round our left edge to the current segment if it encloses us. */ |
| 74 | if (f > rg->from) |
| 75 | f = rg->from; |
| 76 | |
| 77 | /* Check for and consume any regions we now overlap with. */ |
| 78 | nrg = rg; |
| 79 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| 80 | if (&rg->link == head) |
| 81 | break; |
| 82 | if (rg->from > t) |
| 83 | break; |
| 84 | |
| 85 | /* If this area reaches higher then extend our area to |
| 86 | * include it completely. If this is not the first area |
| 87 | * which we intend to reuse, free it. */ |
| 88 | if (rg->to > t) |
| 89 | t = rg->to; |
| 90 | if (rg != nrg) { |
| 91 | list_del(&rg->link); |
| 92 | kfree(rg); |
| 93 | } |
| 94 | } |
| 95 | nrg->from = f; |
| 96 | nrg->to = t; |
| 97 | return 0; |
| 98 | } |
| 99 | |
| 100 | static long region_chg(struct list_head *head, long f, long t) |
| 101 | { |
| 102 | struct file_region *rg, *nrg; |
| 103 | long chg = 0; |
| 104 | |
| 105 | /* Locate the region we are before or in. */ |
| 106 | list_for_each_entry(rg, head, link) |
| 107 | if (f <= rg->to) |
| 108 | break; |
| 109 | |
| 110 | /* If we are below the current region then a new region is required. |
| 111 | * Subtle, allocate a new region at the position but make it zero |
| 112 | * size such that we can guarantee to record the reservation. */ |
| 113 | if (&rg->link == head || t < rg->from) { |
| 114 | nrg = kmalloc(sizeof(*nrg), GFP_KERNEL); |
| 115 | if (!nrg) |
| 116 | return -ENOMEM; |
| 117 | nrg->from = f; |
| 118 | nrg->to = f; |
| 119 | INIT_LIST_HEAD(&nrg->link); |
| 120 | list_add(&nrg->link, rg->link.prev); |
| 121 | |
| 122 | return t - f; |
| 123 | } |
| 124 | |
| 125 | /* Round our left edge to the current segment if it encloses us. */ |
| 126 | if (f > rg->from) |
| 127 | f = rg->from; |
| 128 | chg = t - f; |
| 129 | |
| 130 | /* Check for and consume any regions we now overlap with. */ |
| 131 | list_for_each_entry(rg, rg->link.prev, link) { |
| 132 | if (&rg->link == head) |
| 133 | break; |
| 134 | if (rg->from > t) |
| 135 | return chg; |
| 136 | |
| 137 | /* We overlap with this area, if it extends futher than |
| 138 | * us then we must extend ourselves. Account for its |
| 139 | * existing reservation. */ |
| 140 | if (rg->to > t) { |
| 141 | chg += rg->to - t; |
| 142 | t = rg->to; |
| 143 | } |
| 144 | chg -= rg->to - rg->from; |
| 145 | } |
| 146 | return chg; |
| 147 | } |
| 148 | |
| 149 | static long region_truncate(struct list_head *head, long end) |
| 150 | { |
| 151 | struct file_region *rg, *trg; |
| 152 | long chg = 0; |
| 153 | |
| 154 | /* Locate the region we are either in or before. */ |
| 155 | list_for_each_entry(rg, head, link) |
| 156 | if (end <= rg->to) |
| 157 | break; |
| 158 | if (&rg->link == head) |
| 159 | return 0; |
| 160 | |
| 161 | /* If we are in the middle of a region then adjust it. */ |
| 162 | if (end > rg->from) { |
| 163 | chg = rg->to - end; |
| 164 | rg->to = end; |
| 165 | rg = list_entry(rg->link.next, typeof(*rg), link); |
| 166 | } |
| 167 | |
| 168 | /* Drop any remaining regions. */ |
| 169 | list_for_each_entry_safe(rg, trg, rg->link.prev, link) { |
| 170 | if (&rg->link == head) |
| 171 | break; |
| 172 | chg += rg->to - rg->from; |
| 173 | list_del(&rg->link); |
| 174 | kfree(rg); |
| 175 | } |
| 176 | return chg; |
| 177 | } |
| 178 | |
| 179 | static long region_count(struct list_head *head, long f, long t) |
| 180 | { |
| 181 | struct file_region *rg; |
| 182 | long chg = 0; |
| 183 | |
| 184 | /* Locate each segment we overlap with, and count that overlap. */ |
| 185 | list_for_each_entry(rg, head, link) { |
| 186 | int seg_from; |
| 187 | int seg_to; |
| 188 | |
| 189 | if (rg->to <= f) |
| 190 | continue; |
| 191 | if (rg->from >= t) |
| 192 | break; |
| 193 | |
| 194 | seg_from = max(rg->from, f); |
| 195 | seg_to = min(rg->to, t); |
| 196 | |
| 197 | chg += seg_to - seg_from; |
| 198 | } |
| 199 | |
| 200 | return chg; |
| 201 | } |
| 202 | |
| 203 | /* |
| 204 | * Convert the address within this vma to the page offset within |
| 205 | * the mapping, in pagecache page units; huge pages here. |
| 206 | */ |
| 207 | static pgoff_t vma_hugecache_offset(struct hstate *h, |
| 208 | struct vm_area_struct *vma, unsigned long address) |
| 209 | { |
| 210 | return ((address - vma->vm_start) >> huge_page_shift(h)) + |
| 211 | (vma->vm_pgoff >> huge_page_order(h)); |
| 212 | } |
| 213 | |
| 214 | /* |
| 215 | * Flags for MAP_PRIVATE reservations. These are stored in the bottom |
| 216 | * bits of the reservation map pointer, which are always clear due to |
| 217 | * alignment. |
| 218 | */ |
| 219 | #define HPAGE_RESV_OWNER (1UL << 0) |
| 220 | #define HPAGE_RESV_UNMAPPED (1UL << 1) |
| 221 | #define HPAGE_RESV_MASK (HPAGE_RESV_OWNER | HPAGE_RESV_UNMAPPED) |
| 222 | |
| 223 | /* |
| 224 | * These helpers are used to track how many pages are reserved for |
| 225 | * faults in a MAP_PRIVATE mapping. Only the process that called mmap() |
| 226 | * is guaranteed to have their future faults succeed. |
| 227 | * |
| 228 | * With the exception of reset_vma_resv_huge_pages() which is called at fork(), |
| 229 | * the reserve counters are updated with the hugetlb_lock held. It is safe |
| 230 | * to reset the VMA at fork() time as it is not in use yet and there is no |
| 231 | * chance of the global counters getting corrupted as a result of the values. |
| 232 | * |
| 233 | * The private mapping reservation is represented in a subtly different |
| 234 | * manner to a shared mapping. A shared mapping has a region map associated |
| 235 | * with the underlying file, this region map represents the backing file |
| 236 | * pages which have ever had a reservation assigned which this persists even |
| 237 | * after the page is instantiated. A private mapping has a region map |
| 238 | * associated with the original mmap which is attached to all VMAs which |
| 239 | * reference it, this region map represents those offsets which have consumed |
| 240 | * reservation ie. where pages have been instantiated. |
| 241 | */ |
| 242 | static unsigned long get_vma_private_data(struct vm_area_struct *vma) |
| 243 | { |
| 244 | return (unsigned long)vma->vm_private_data; |
| 245 | } |
| 246 | |
| 247 | static void set_vma_private_data(struct vm_area_struct *vma, |
| 248 | unsigned long value) |
| 249 | { |
| 250 | vma->vm_private_data = (void *)value; |
| 251 | } |
| 252 | |
| 253 | struct resv_map { |
| 254 | struct kref refs; |
| 255 | struct list_head regions; |
| 256 | }; |
| 257 | |
| 258 | struct resv_map *resv_map_alloc(void) |
| 259 | { |
| 260 | struct resv_map *resv_map = kmalloc(sizeof(*resv_map), GFP_KERNEL); |
| 261 | if (!resv_map) |
| 262 | return NULL; |
| 263 | |
| 264 | kref_init(&resv_map->refs); |
| 265 | INIT_LIST_HEAD(&resv_map->regions); |
| 266 | |
| 267 | return resv_map; |
| 268 | } |
| 269 | |
| 270 | void resv_map_release(struct kref *ref) |
| 271 | { |
| 272 | struct resv_map *resv_map = container_of(ref, struct resv_map, refs); |
| 273 | |
| 274 | /* Clear out any active regions before we release the map. */ |
| 275 | region_truncate(&resv_map->regions, 0); |
| 276 | kfree(resv_map); |
| 277 | } |
| 278 | |
| 279 | static struct resv_map *vma_resv_map(struct vm_area_struct *vma) |
| 280 | { |
| 281 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| 282 | if (!(vma->vm_flags & VM_SHARED)) |
| 283 | return (struct resv_map *)(get_vma_private_data(vma) & |
| 284 | ~HPAGE_RESV_MASK); |
| 285 | return 0; |
| 286 | } |
| 287 | |
| 288 | static void set_vma_resv_map(struct vm_area_struct *vma, struct resv_map *map) |
| 289 | { |
| 290 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| 291 | VM_BUG_ON(vma->vm_flags & VM_SHARED); |
| 292 | |
| 293 | set_vma_private_data(vma, (get_vma_private_data(vma) & |
| 294 | HPAGE_RESV_MASK) | (unsigned long)map); |
| 295 | } |
| 296 | |
| 297 | static void set_vma_resv_flags(struct vm_area_struct *vma, unsigned long flags) |
| 298 | { |
| 299 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| 300 | VM_BUG_ON(vma->vm_flags & VM_SHARED); |
| 301 | |
| 302 | set_vma_private_data(vma, get_vma_private_data(vma) | flags); |
| 303 | } |
| 304 | |
| 305 | static int is_vma_resv_set(struct vm_area_struct *vma, unsigned long flag) |
| 306 | { |
| 307 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| 308 | |
| 309 | return (get_vma_private_data(vma) & flag) != 0; |
| 310 | } |
| 311 | |
| 312 | /* Decrement the reserved pages in the hugepage pool by one */ |
| 313 | static void decrement_hugepage_resv_vma(struct hstate *h, |
| 314 | struct vm_area_struct *vma) |
| 315 | { |
| 316 | if (vma->vm_flags & VM_NORESERVE) |
| 317 | return; |
| 318 | |
| 319 | if (vma->vm_flags & VM_SHARED) { |
| 320 | /* Shared mappings always use reserves */ |
| 321 | h->resv_huge_pages--; |
| 322 | } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| 323 | /* |
| 324 | * Only the process that called mmap() has reserves for |
| 325 | * private mappings. |
| 326 | */ |
| 327 | h->resv_huge_pages--; |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | /* Reset counters to 0 and clear all HPAGE_RESV_* flags */ |
| 332 | void reset_vma_resv_huge_pages(struct vm_area_struct *vma) |
| 333 | { |
| 334 | VM_BUG_ON(!is_vm_hugetlb_page(vma)); |
| 335 | if (!(vma->vm_flags & VM_SHARED)) |
| 336 | vma->vm_private_data = (void *)0; |
| 337 | } |
| 338 | |
| 339 | /* Returns true if the VMA has associated reserve pages */ |
| 340 | static int vma_has_private_reserves(struct vm_area_struct *vma) |
| 341 | { |
| 342 | if (vma->vm_flags & VM_SHARED) |
| 343 | return 0; |
| 344 | if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) |
| 345 | return 0; |
| 346 | return 1; |
| 347 | } |
| 348 | |
| 349 | static void clear_huge_page(struct page *page, |
| 350 | unsigned long addr, unsigned long sz) |
| 351 | { |
| 352 | int i; |
| 353 | |
| 354 | might_sleep(); |
| 355 | for (i = 0; i < sz/PAGE_SIZE; i++) { |
| 356 | cond_resched(); |
| 357 | clear_user_highpage(page + i, addr + i * PAGE_SIZE); |
| 358 | } |
| 359 | } |
| 360 | |
| 361 | static void copy_huge_page(struct page *dst, struct page *src, |
| 362 | unsigned long addr, struct vm_area_struct *vma) |
| 363 | { |
| 364 | int i; |
| 365 | struct hstate *h = hstate_vma(vma); |
| 366 | |
| 367 | might_sleep(); |
| 368 | for (i = 0; i < pages_per_huge_page(h); i++) { |
| 369 | cond_resched(); |
| 370 | copy_user_highpage(dst + i, src + i, addr + i*PAGE_SIZE, vma); |
| 371 | } |
| 372 | } |
| 373 | |
| 374 | static void enqueue_huge_page(struct hstate *h, struct page *page) |
| 375 | { |
| 376 | int nid = page_to_nid(page); |
| 377 | list_add(&page->lru, &h->hugepage_freelists[nid]); |
| 378 | h->free_huge_pages++; |
| 379 | h->free_huge_pages_node[nid]++; |
| 380 | } |
| 381 | |
| 382 | static struct page *dequeue_huge_page(struct hstate *h) |
| 383 | { |
| 384 | int nid; |
| 385 | struct page *page = NULL; |
| 386 | |
| 387 | for (nid = 0; nid < MAX_NUMNODES; ++nid) { |
| 388 | if (!list_empty(&h->hugepage_freelists[nid])) { |
| 389 | page = list_entry(h->hugepage_freelists[nid].next, |
| 390 | struct page, lru); |
| 391 | list_del(&page->lru); |
| 392 | h->free_huge_pages--; |
| 393 | h->free_huge_pages_node[nid]--; |
| 394 | break; |
| 395 | } |
| 396 | } |
| 397 | return page; |
| 398 | } |
| 399 | |
| 400 | static struct page *dequeue_huge_page_vma(struct hstate *h, |
| 401 | struct vm_area_struct *vma, |
| 402 | unsigned long address, int avoid_reserve) |
| 403 | { |
| 404 | int nid; |
| 405 | struct page *page = NULL; |
| 406 | struct mempolicy *mpol; |
| 407 | nodemask_t *nodemask; |
| 408 | struct zonelist *zonelist = huge_zonelist(vma, address, |
| 409 | htlb_alloc_mask, &mpol, &nodemask); |
| 410 | struct zone *zone; |
| 411 | struct zoneref *z; |
| 412 | |
| 413 | /* |
| 414 | * A child process with MAP_PRIVATE mappings created by their parent |
| 415 | * have no page reserves. This check ensures that reservations are |
| 416 | * not "stolen". The child may still get SIGKILLed |
| 417 | */ |
| 418 | if (!vma_has_private_reserves(vma) && |
| 419 | h->free_huge_pages - h->resv_huge_pages == 0) |
| 420 | return NULL; |
| 421 | |
| 422 | /* If reserves cannot be used, ensure enough pages are in the pool */ |
| 423 | if (avoid_reserve && h->free_huge_pages - h->resv_huge_pages == 0) |
| 424 | return NULL; |
| 425 | |
| 426 | for_each_zone_zonelist_nodemask(zone, z, zonelist, |
| 427 | MAX_NR_ZONES - 1, nodemask) { |
| 428 | nid = zone_to_nid(zone); |
| 429 | if (cpuset_zone_allowed_softwall(zone, htlb_alloc_mask) && |
| 430 | !list_empty(&h->hugepage_freelists[nid])) { |
| 431 | page = list_entry(h->hugepage_freelists[nid].next, |
| 432 | struct page, lru); |
| 433 | list_del(&page->lru); |
| 434 | h->free_huge_pages--; |
| 435 | h->free_huge_pages_node[nid]--; |
| 436 | |
| 437 | if (!avoid_reserve) |
| 438 | decrement_hugepage_resv_vma(h, vma); |
| 439 | |
| 440 | break; |
| 441 | } |
| 442 | } |
| 443 | mpol_cond_put(mpol); |
| 444 | return page; |
| 445 | } |
| 446 | |
| 447 | static void update_and_free_page(struct hstate *h, struct page *page) |
| 448 | { |
| 449 | int i; |
| 450 | |
| 451 | h->nr_huge_pages--; |
| 452 | h->nr_huge_pages_node[page_to_nid(page)]--; |
| 453 | for (i = 0; i < pages_per_huge_page(h); i++) { |
| 454 | page[i].flags &= ~(1 << PG_locked | 1 << PG_error | 1 << PG_referenced | |
| 455 | 1 << PG_dirty | 1 << PG_active | 1 << PG_reserved | |
| 456 | 1 << PG_private | 1<< PG_writeback); |
| 457 | } |
| 458 | set_compound_page_dtor(page, NULL); |
| 459 | set_page_refcounted(page); |
| 460 | arch_release_hugepage(page); |
| 461 | __free_pages(page, huge_page_order(h)); |
| 462 | } |
| 463 | |
| 464 | struct hstate *size_to_hstate(unsigned long size) |
| 465 | { |
| 466 | struct hstate *h; |
| 467 | |
| 468 | for_each_hstate(h) { |
| 469 | if (huge_page_size(h) == size) |
| 470 | return h; |
| 471 | } |
| 472 | return NULL; |
| 473 | } |
| 474 | |
| 475 | static void free_huge_page(struct page *page) |
| 476 | { |
| 477 | /* |
| 478 | * Can't pass hstate in here because it is called from the |
| 479 | * compound page destructor. |
| 480 | */ |
| 481 | struct hstate *h = page_hstate(page); |
| 482 | int nid = page_to_nid(page); |
| 483 | struct address_space *mapping; |
| 484 | |
| 485 | mapping = (struct address_space *) page_private(page); |
| 486 | set_page_private(page, 0); |
| 487 | BUG_ON(page_count(page)); |
| 488 | INIT_LIST_HEAD(&page->lru); |
| 489 | |
| 490 | spin_lock(&hugetlb_lock); |
| 491 | if (h->surplus_huge_pages_node[nid]) { |
| 492 | update_and_free_page(h, page); |
| 493 | h->surplus_huge_pages--; |
| 494 | h->surplus_huge_pages_node[nid]--; |
| 495 | } else { |
| 496 | enqueue_huge_page(h, page); |
| 497 | } |
| 498 | spin_unlock(&hugetlb_lock); |
| 499 | if (mapping) |
| 500 | hugetlb_put_quota(mapping, 1); |
| 501 | } |
| 502 | |
| 503 | /* |
| 504 | * Increment or decrement surplus_huge_pages. Keep node-specific counters |
| 505 | * balanced by operating on them in a round-robin fashion. |
| 506 | * Returns 1 if an adjustment was made. |
| 507 | */ |
| 508 | static int adjust_pool_surplus(struct hstate *h, int delta) |
| 509 | { |
| 510 | static int prev_nid; |
| 511 | int nid = prev_nid; |
| 512 | int ret = 0; |
| 513 | |
| 514 | VM_BUG_ON(delta != -1 && delta != 1); |
| 515 | do { |
| 516 | nid = next_node(nid, node_online_map); |
| 517 | if (nid == MAX_NUMNODES) |
| 518 | nid = first_node(node_online_map); |
| 519 | |
| 520 | /* To shrink on this node, there must be a surplus page */ |
| 521 | if (delta < 0 && !h->surplus_huge_pages_node[nid]) |
| 522 | continue; |
| 523 | /* Surplus cannot exceed the total number of pages */ |
| 524 | if (delta > 0 && h->surplus_huge_pages_node[nid] >= |
| 525 | h->nr_huge_pages_node[nid]) |
| 526 | continue; |
| 527 | |
| 528 | h->surplus_huge_pages += delta; |
| 529 | h->surplus_huge_pages_node[nid] += delta; |
| 530 | ret = 1; |
| 531 | break; |
| 532 | } while (nid != prev_nid); |
| 533 | |
| 534 | prev_nid = nid; |
| 535 | return ret; |
| 536 | } |
| 537 | |
| 538 | static void prep_new_huge_page(struct hstate *h, struct page *page, int nid) |
| 539 | { |
| 540 | set_compound_page_dtor(page, free_huge_page); |
| 541 | spin_lock(&hugetlb_lock); |
| 542 | h->nr_huge_pages++; |
| 543 | h->nr_huge_pages_node[nid]++; |
| 544 | spin_unlock(&hugetlb_lock); |
| 545 | put_page(page); /* free it into the hugepage allocator */ |
| 546 | } |
| 547 | |
| 548 | static struct page *alloc_fresh_huge_page_node(struct hstate *h, int nid) |
| 549 | { |
| 550 | struct page *page; |
| 551 | |
| 552 | page = alloc_pages_node(nid, |
| 553 | htlb_alloc_mask|__GFP_COMP|__GFP_THISNODE| |
| 554 | __GFP_REPEAT|__GFP_NOWARN, |
| 555 | huge_page_order(h)); |
| 556 | if (page) { |
| 557 | if (arch_prepare_hugepage(page)) { |
| 558 | __free_pages(page, HUGETLB_PAGE_ORDER); |
| 559 | return NULL; |
| 560 | } |
| 561 | prep_new_huge_page(h, page, nid); |
| 562 | } |
| 563 | |
| 564 | return page; |
| 565 | } |
| 566 | |
| 567 | static int alloc_fresh_huge_page(struct hstate *h) |
| 568 | { |
| 569 | struct page *page; |
| 570 | int start_nid; |
| 571 | int next_nid; |
| 572 | int ret = 0; |
| 573 | |
| 574 | start_nid = h->hugetlb_next_nid; |
| 575 | |
| 576 | do { |
| 577 | page = alloc_fresh_huge_page_node(h, h->hugetlb_next_nid); |
| 578 | if (page) |
| 579 | ret = 1; |
| 580 | /* |
| 581 | * Use a helper variable to find the next node and then |
| 582 | * copy it back to hugetlb_next_nid afterwards: |
| 583 | * otherwise there's a window in which a racer might |
| 584 | * pass invalid nid MAX_NUMNODES to alloc_pages_node. |
| 585 | * But we don't need to use a spin_lock here: it really |
| 586 | * doesn't matter if occasionally a racer chooses the |
| 587 | * same nid as we do. Move nid forward in the mask even |
| 588 | * if we just successfully allocated a hugepage so that |
| 589 | * the next caller gets hugepages on the next node. |
| 590 | */ |
| 591 | next_nid = next_node(h->hugetlb_next_nid, node_online_map); |
| 592 | if (next_nid == MAX_NUMNODES) |
| 593 | next_nid = first_node(node_online_map); |
| 594 | h->hugetlb_next_nid = next_nid; |
| 595 | } while (!page && h->hugetlb_next_nid != start_nid); |
| 596 | |
| 597 | if (ret) |
| 598 | count_vm_event(HTLB_BUDDY_PGALLOC); |
| 599 | else |
| 600 | count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| 601 | |
| 602 | return ret; |
| 603 | } |
| 604 | |
| 605 | static struct page *alloc_buddy_huge_page(struct hstate *h, |
| 606 | struct vm_area_struct *vma, unsigned long address) |
| 607 | { |
| 608 | struct page *page; |
| 609 | unsigned int nid; |
| 610 | |
| 611 | /* |
| 612 | * Assume we will successfully allocate the surplus page to |
| 613 | * prevent racing processes from causing the surplus to exceed |
| 614 | * overcommit |
| 615 | * |
| 616 | * This however introduces a different race, where a process B |
| 617 | * tries to grow the static hugepage pool while alloc_pages() is |
| 618 | * called by process A. B will only examine the per-node |
| 619 | * counters in determining if surplus huge pages can be |
| 620 | * converted to normal huge pages in adjust_pool_surplus(). A |
| 621 | * won't be able to increment the per-node counter, until the |
| 622 | * lock is dropped by B, but B doesn't drop hugetlb_lock until |
| 623 | * no more huge pages can be converted from surplus to normal |
| 624 | * state (and doesn't try to convert again). Thus, we have a |
| 625 | * case where a surplus huge page exists, the pool is grown, and |
| 626 | * the surplus huge page still exists after, even though it |
| 627 | * should just have been converted to a normal huge page. This |
| 628 | * does not leak memory, though, as the hugepage will be freed |
| 629 | * once it is out of use. It also does not allow the counters to |
| 630 | * go out of whack in adjust_pool_surplus() as we don't modify |
| 631 | * the node values until we've gotten the hugepage and only the |
| 632 | * per-node value is checked there. |
| 633 | */ |
| 634 | spin_lock(&hugetlb_lock); |
| 635 | if (h->surplus_huge_pages >= h->nr_overcommit_huge_pages) { |
| 636 | spin_unlock(&hugetlb_lock); |
| 637 | return NULL; |
| 638 | } else { |
| 639 | h->nr_huge_pages++; |
| 640 | h->surplus_huge_pages++; |
| 641 | } |
| 642 | spin_unlock(&hugetlb_lock); |
| 643 | |
| 644 | page = alloc_pages(htlb_alloc_mask|__GFP_COMP| |
| 645 | __GFP_REPEAT|__GFP_NOWARN, |
| 646 | huge_page_order(h)); |
| 647 | |
| 648 | spin_lock(&hugetlb_lock); |
| 649 | if (page) { |
| 650 | /* |
| 651 | * This page is now managed by the hugetlb allocator and has |
| 652 | * no users -- drop the buddy allocator's reference. |
| 653 | */ |
| 654 | put_page_testzero(page); |
| 655 | VM_BUG_ON(page_count(page)); |
| 656 | nid = page_to_nid(page); |
| 657 | set_compound_page_dtor(page, free_huge_page); |
| 658 | /* |
| 659 | * We incremented the global counters already |
| 660 | */ |
| 661 | h->nr_huge_pages_node[nid]++; |
| 662 | h->surplus_huge_pages_node[nid]++; |
| 663 | __count_vm_event(HTLB_BUDDY_PGALLOC); |
| 664 | } else { |
| 665 | h->nr_huge_pages--; |
| 666 | h->surplus_huge_pages--; |
| 667 | __count_vm_event(HTLB_BUDDY_PGALLOC_FAIL); |
| 668 | } |
| 669 | spin_unlock(&hugetlb_lock); |
| 670 | |
| 671 | return page; |
| 672 | } |
| 673 | |
| 674 | /* |
| 675 | * Increase the hugetlb pool such that it can accomodate a reservation |
| 676 | * of size 'delta'. |
| 677 | */ |
| 678 | static int gather_surplus_pages(struct hstate *h, int delta) |
| 679 | { |
| 680 | struct list_head surplus_list; |
| 681 | struct page *page, *tmp; |
| 682 | int ret, i; |
| 683 | int needed, allocated; |
| 684 | |
| 685 | needed = (h->resv_huge_pages + delta) - h->free_huge_pages; |
| 686 | if (needed <= 0) { |
| 687 | h->resv_huge_pages += delta; |
| 688 | return 0; |
| 689 | } |
| 690 | |
| 691 | allocated = 0; |
| 692 | INIT_LIST_HEAD(&surplus_list); |
| 693 | |
| 694 | ret = -ENOMEM; |
| 695 | retry: |
| 696 | spin_unlock(&hugetlb_lock); |
| 697 | for (i = 0; i < needed; i++) { |
| 698 | page = alloc_buddy_huge_page(h, NULL, 0); |
| 699 | if (!page) { |
| 700 | /* |
| 701 | * We were not able to allocate enough pages to |
| 702 | * satisfy the entire reservation so we free what |
| 703 | * we've allocated so far. |
| 704 | */ |
| 705 | spin_lock(&hugetlb_lock); |
| 706 | needed = 0; |
| 707 | goto free; |
| 708 | } |
| 709 | |
| 710 | list_add(&page->lru, &surplus_list); |
| 711 | } |
| 712 | allocated += needed; |
| 713 | |
| 714 | /* |
| 715 | * After retaking hugetlb_lock, we need to recalculate 'needed' |
| 716 | * because either resv_huge_pages or free_huge_pages may have changed. |
| 717 | */ |
| 718 | spin_lock(&hugetlb_lock); |
| 719 | needed = (h->resv_huge_pages + delta) - |
| 720 | (h->free_huge_pages + allocated); |
| 721 | if (needed > 0) |
| 722 | goto retry; |
| 723 | |
| 724 | /* |
| 725 | * The surplus_list now contains _at_least_ the number of extra pages |
| 726 | * needed to accomodate the reservation. Add the appropriate number |
| 727 | * of pages to the hugetlb pool and free the extras back to the buddy |
| 728 | * allocator. Commit the entire reservation here to prevent another |
| 729 | * process from stealing the pages as they are added to the pool but |
| 730 | * before they are reserved. |
| 731 | */ |
| 732 | needed += allocated; |
| 733 | h->resv_huge_pages += delta; |
| 734 | ret = 0; |
| 735 | free: |
| 736 | /* Free the needed pages to the hugetlb pool */ |
| 737 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| 738 | if ((--needed) < 0) |
| 739 | break; |
| 740 | list_del(&page->lru); |
| 741 | enqueue_huge_page(h, page); |
| 742 | } |
| 743 | |
| 744 | /* Free unnecessary surplus pages to the buddy allocator */ |
| 745 | if (!list_empty(&surplus_list)) { |
| 746 | spin_unlock(&hugetlb_lock); |
| 747 | list_for_each_entry_safe(page, tmp, &surplus_list, lru) { |
| 748 | list_del(&page->lru); |
| 749 | /* |
| 750 | * The page has a reference count of zero already, so |
| 751 | * call free_huge_page directly instead of using |
| 752 | * put_page. This must be done with hugetlb_lock |
| 753 | * unlocked which is safe because free_huge_page takes |
| 754 | * hugetlb_lock before deciding how to free the page. |
| 755 | */ |
| 756 | free_huge_page(page); |
| 757 | } |
| 758 | spin_lock(&hugetlb_lock); |
| 759 | } |
| 760 | |
| 761 | return ret; |
| 762 | } |
| 763 | |
| 764 | /* |
| 765 | * When releasing a hugetlb pool reservation, any surplus pages that were |
| 766 | * allocated to satisfy the reservation must be explicitly freed if they were |
| 767 | * never used. |
| 768 | */ |
| 769 | static void return_unused_surplus_pages(struct hstate *h, |
| 770 | unsigned long unused_resv_pages) |
| 771 | { |
| 772 | static int nid = -1; |
| 773 | struct page *page; |
| 774 | unsigned long nr_pages; |
| 775 | |
| 776 | /* |
| 777 | * We want to release as many surplus pages as possible, spread |
| 778 | * evenly across all nodes. Iterate across all nodes until we |
| 779 | * can no longer free unreserved surplus pages. This occurs when |
| 780 | * the nodes with surplus pages have no free pages. |
| 781 | */ |
| 782 | unsigned long remaining_iterations = num_online_nodes(); |
| 783 | |
| 784 | /* Uncommit the reservation */ |
| 785 | h->resv_huge_pages -= unused_resv_pages; |
| 786 | |
| 787 | nr_pages = min(unused_resv_pages, h->surplus_huge_pages); |
| 788 | |
| 789 | while (remaining_iterations-- && nr_pages) { |
| 790 | nid = next_node(nid, node_online_map); |
| 791 | if (nid == MAX_NUMNODES) |
| 792 | nid = first_node(node_online_map); |
| 793 | |
| 794 | if (!h->surplus_huge_pages_node[nid]) |
| 795 | continue; |
| 796 | |
| 797 | if (!list_empty(&h->hugepage_freelists[nid])) { |
| 798 | page = list_entry(h->hugepage_freelists[nid].next, |
| 799 | struct page, lru); |
| 800 | list_del(&page->lru); |
| 801 | update_and_free_page(h, page); |
| 802 | h->free_huge_pages--; |
| 803 | h->free_huge_pages_node[nid]--; |
| 804 | h->surplus_huge_pages--; |
| 805 | h->surplus_huge_pages_node[nid]--; |
| 806 | nr_pages--; |
| 807 | remaining_iterations = num_online_nodes(); |
| 808 | } |
| 809 | } |
| 810 | } |
| 811 | |
| 812 | /* |
| 813 | * Determine if the huge page at addr within the vma has an associated |
| 814 | * reservation. Where it does not we will need to logically increase |
| 815 | * reservation and actually increase quota before an allocation can occur. |
| 816 | * Where any new reservation would be required the reservation change is |
| 817 | * prepared, but not committed. Once the page has been quota'd allocated |
| 818 | * an instantiated the change should be committed via vma_commit_reservation. |
| 819 | * No action is required on failure. |
| 820 | */ |
| 821 | static int vma_needs_reservation(struct hstate *h, |
| 822 | struct vm_area_struct *vma, unsigned long addr) |
| 823 | { |
| 824 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 825 | struct inode *inode = mapping->host; |
| 826 | |
| 827 | if (vma->vm_flags & VM_SHARED) { |
| 828 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| 829 | return region_chg(&inode->i_mapping->private_list, |
| 830 | idx, idx + 1); |
| 831 | |
| 832 | } else if (!is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| 833 | return 1; |
| 834 | |
| 835 | } else { |
| 836 | int err; |
| 837 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| 838 | struct resv_map *reservations = vma_resv_map(vma); |
| 839 | |
| 840 | err = region_chg(&reservations->regions, idx, idx + 1); |
| 841 | if (err < 0) |
| 842 | return err; |
| 843 | return 0; |
| 844 | } |
| 845 | } |
| 846 | static void vma_commit_reservation(struct hstate *h, |
| 847 | struct vm_area_struct *vma, unsigned long addr) |
| 848 | { |
| 849 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 850 | struct inode *inode = mapping->host; |
| 851 | |
| 852 | if (vma->vm_flags & VM_SHARED) { |
| 853 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| 854 | region_add(&inode->i_mapping->private_list, idx, idx + 1); |
| 855 | |
| 856 | } else if (is_vma_resv_set(vma, HPAGE_RESV_OWNER)) { |
| 857 | pgoff_t idx = vma_hugecache_offset(h, vma, addr); |
| 858 | struct resv_map *reservations = vma_resv_map(vma); |
| 859 | |
| 860 | /* Mark this page used in the map. */ |
| 861 | region_add(&reservations->regions, idx, idx + 1); |
| 862 | } |
| 863 | } |
| 864 | |
| 865 | static struct page *alloc_huge_page(struct vm_area_struct *vma, |
| 866 | unsigned long addr, int avoid_reserve) |
| 867 | { |
| 868 | struct hstate *h = hstate_vma(vma); |
| 869 | struct page *page; |
| 870 | struct address_space *mapping = vma->vm_file->f_mapping; |
| 871 | struct inode *inode = mapping->host; |
| 872 | unsigned int chg; |
| 873 | |
| 874 | /* |
| 875 | * Processes that did not create the mapping will have no reserves and |
| 876 | * will not have accounted against quota. Check that the quota can be |
| 877 | * made before satisfying the allocation |
| 878 | * MAP_NORESERVE mappings may also need pages and quota allocated |
| 879 | * if no reserve mapping overlaps. |
| 880 | */ |
| 881 | chg = vma_needs_reservation(h, vma, addr); |
| 882 | if (chg < 0) |
| 883 | return ERR_PTR(chg); |
| 884 | if (chg) |
| 885 | if (hugetlb_get_quota(inode->i_mapping, chg)) |
| 886 | return ERR_PTR(-ENOSPC); |
| 887 | |
| 888 | spin_lock(&hugetlb_lock); |
| 889 | page = dequeue_huge_page_vma(h, vma, addr, avoid_reserve); |
| 890 | spin_unlock(&hugetlb_lock); |
| 891 | |
| 892 | if (!page) { |
| 893 | page = alloc_buddy_huge_page(h, vma, addr); |
| 894 | if (!page) { |
| 895 | hugetlb_put_quota(inode->i_mapping, chg); |
| 896 | return ERR_PTR(-VM_FAULT_OOM); |
| 897 | } |
| 898 | } |
| 899 | |
| 900 | set_page_refcounted(page); |
| 901 | set_page_private(page, (unsigned long) mapping); |
| 902 | |
| 903 | vma_commit_reservation(h, vma, addr); |
| 904 | |
| 905 | return page; |
| 906 | } |
| 907 | |
| 908 | static void __init hugetlb_init_one_hstate(struct hstate *h) |
| 909 | { |
| 910 | unsigned long i; |
| 911 | |
| 912 | for (i = 0; i < MAX_NUMNODES; ++i) |
| 913 | INIT_LIST_HEAD(&h->hugepage_freelists[i]); |
| 914 | |
| 915 | h->hugetlb_next_nid = first_node(node_online_map); |
| 916 | |
| 917 | for (i = 0; i < h->max_huge_pages; ++i) { |
| 918 | if (!alloc_fresh_huge_page(h)) |
| 919 | break; |
| 920 | } |
| 921 | h->max_huge_pages = h->free_huge_pages = h->nr_huge_pages = i; |
| 922 | } |
| 923 | |
| 924 | static void __init hugetlb_init_hstates(void) |
| 925 | { |
| 926 | struct hstate *h; |
| 927 | |
| 928 | for_each_hstate(h) { |
| 929 | hugetlb_init_one_hstate(h); |
| 930 | } |
| 931 | } |
| 932 | |
| 933 | static void __init report_hugepages(void) |
| 934 | { |
| 935 | struct hstate *h; |
| 936 | |
| 937 | for_each_hstate(h) { |
| 938 | printk(KERN_INFO "Total HugeTLB memory allocated, " |
| 939 | "%ld %dMB pages\n", |
| 940 | h->free_huge_pages, |
| 941 | 1 << (h->order + PAGE_SHIFT - 20)); |
| 942 | } |
| 943 | } |
| 944 | |
| 945 | static int __init hugetlb_init(void) |
| 946 | { |
| 947 | BUILD_BUG_ON(HPAGE_SHIFT == 0); |
| 948 | |
| 949 | if (!size_to_hstate(HPAGE_SIZE)) { |
| 950 | hugetlb_add_hstate(HUGETLB_PAGE_ORDER); |
| 951 | parsed_hstate->max_huge_pages = default_hstate_max_huge_pages; |
| 952 | } |
| 953 | default_hstate_idx = size_to_hstate(HPAGE_SIZE) - hstates; |
| 954 | |
| 955 | hugetlb_init_hstates(); |
| 956 | |
| 957 | report_hugepages(); |
| 958 | |
| 959 | return 0; |
| 960 | } |
| 961 | module_init(hugetlb_init); |
| 962 | |
| 963 | /* Should be called on processing a hugepagesz=... option */ |
| 964 | void __init hugetlb_add_hstate(unsigned order) |
| 965 | { |
| 966 | struct hstate *h; |
| 967 | if (size_to_hstate(PAGE_SIZE << order)) { |
| 968 | printk(KERN_WARNING "hugepagesz= specified twice, ignoring\n"); |
| 969 | return; |
| 970 | } |
| 971 | BUG_ON(max_hstate >= HUGE_MAX_HSTATE); |
| 972 | BUG_ON(order == 0); |
| 973 | h = &hstates[max_hstate++]; |
| 974 | h->order = order; |
| 975 | h->mask = ~((1ULL << (order + PAGE_SHIFT)) - 1); |
| 976 | hugetlb_init_one_hstate(h); |
| 977 | parsed_hstate = h; |
| 978 | } |
| 979 | |
| 980 | static int __init hugetlb_setup(char *s) |
| 981 | { |
| 982 | unsigned long *mhp; |
| 983 | |
| 984 | /* |
| 985 | * !max_hstate means we haven't parsed a hugepagesz= parameter yet, |
| 986 | * so this hugepages= parameter goes to the "default hstate". |
| 987 | */ |
| 988 | if (!max_hstate) |
| 989 | mhp = &default_hstate_max_huge_pages; |
| 990 | else |
| 991 | mhp = &parsed_hstate->max_huge_pages; |
| 992 | |
| 993 | if (sscanf(s, "%lu", mhp) <= 0) |
| 994 | *mhp = 0; |
| 995 | |
| 996 | return 1; |
| 997 | } |
| 998 | __setup("hugepages=", hugetlb_setup); |
| 999 | |
| 1000 | static unsigned int cpuset_mems_nr(unsigned int *array) |
| 1001 | { |
| 1002 | int node; |
| 1003 | unsigned int nr = 0; |
| 1004 | |
| 1005 | for_each_node_mask(node, cpuset_current_mems_allowed) |
| 1006 | nr += array[node]; |
| 1007 | |
| 1008 | return nr; |
| 1009 | } |
| 1010 | |
| 1011 | #ifdef CONFIG_SYSCTL |
| 1012 | #ifdef CONFIG_HIGHMEM |
| 1013 | static void try_to_free_low(struct hstate *h, unsigned long count) |
| 1014 | { |
| 1015 | int i; |
| 1016 | |
| 1017 | for (i = 0; i < MAX_NUMNODES; ++i) { |
| 1018 | struct page *page, *next; |
| 1019 | struct list_head *freel = &h->hugepage_freelists[i]; |
| 1020 | list_for_each_entry_safe(page, next, freel, lru) { |
| 1021 | if (count >= h->nr_huge_pages) |
| 1022 | return; |
| 1023 | if (PageHighMem(page)) |
| 1024 | continue; |
| 1025 | list_del(&page->lru); |
| 1026 | update_and_free_page(h, page); |
| 1027 | h->free_huge_pages--; |
| 1028 | h->free_huge_pages_node[page_to_nid(page)]--; |
| 1029 | } |
| 1030 | } |
| 1031 | } |
| 1032 | #else |
| 1033 | static inline void try_to_free_low(struct hstate *h, unsigned long count) |
| 1034 | { |
| 1035 | } |
| 1036 | #endif |
| 1037 | |
| 1038 | #define persistent_huge_pages(h) (h->nr_huge_pages - h->surplus_huge_pages) |
| 1039 | static unsigned long set_max_huge_pages(struct hstate *h, unsigned long count) |
| 1040 | { |
| 1041 | unsigned long min_count, ret; |
| 1042 | |
| 1043 | /* |
| 1044 | * Increase the pool size |
| 1045 | * First take pages out of surplus state. Then make up the |
| 1046 | * remaining difference by allocating fresh huge pages. |
| 1047 | * |
| 1048 | * We might race with alloc_buddy_huge_page() here and be unable |
| 1049 | * to convert a surplus huge page to a normal huge page. That is |
| 1050 | * not critical, though, it just means the overall size of the |
| 1051 | * pool might be one hugepage larger than it needs to be, but |
| 1052 | * within all the constraints specified by the sysctls. |
| 1053 | */ |
| 1054 | spin_lock(&hugetlb_lock); |
| 1055 | while (h->surplus_huge_pages && count > persistent_huge_pages(h)) { |
| 1056 | if (!adjust_pool_surplus(h, -1)) |
| 1057 | break; |
| 1058 | } |
| 1059 | |
| 1060 | while (count > persistent_huge_pages(h)) { |
| 1061 | /* |
| 1062 | * If this allocation races such that we no longer need the |
| 1063 | * page, free_huge_page will handle it by freeing the page |
| 1064 | * and reducing the surplus. |
| 1065 | */ |
| 1066 | spin_unlock(&hugetlb_lock); |
| 1067 | ret = alloc_fresh_huge_page(h); |
| 1068 | spin_lock(&hugetlb_lock); |
| 1069 | if (!ret) |
| 1070 | goto out; |
| 1071 | |
| 1072 | } |
| 1073 | |
| 1074 | /* |
| 1075 | * Decrease the pool size |
| 1076 | * First return free pages to the buddy allocator (being careful |
| 1077 | * to keep enough around to satisfy reservations). Then place |
| 1078 | * pages into surplus state as needed so the pool will shrink |
| 1079 | * to the desired size as pages become free. |
| 1080 | * |
| 1081 | * By placing pages into the surplus state independent of the |
| 1082 | * overcommit value, we are allowing the surplus pool size to |
| 1083 | * exceed overcommit. There are few sane options here. Since |
| 1084 | * alloc_buddy_huge_page() is checking the global counter, |
| 1085 | * though, we'll note that we're not allowed to exceed surplus |
| 1086 | * and won't grow the pool anywhere else. Not until one of the |
| 1087 | * sysctls are changed, or the surplus pages go out of use. |
| 1088 | */ |
| 1089 | min_count = h->resv_huge_pages + h->nr_huge_pages - h->free_huge_pages; |
| 1090 | min_count = max(count, min_count); |
| 1091 | try_to_free_low(h, min_count); |
| 1092 | while (min_count < persistent_huge_pages(h)) { |
| 1093 | struct page *page = dequeue_huge_page(h); |
| 1094 | if (!page) |
| 1095 | break; |
| 1096 | update_and_free_page(h, page); |
| 1097 | } |
| 1098 | while (count < persistent_huge_pages(h)) { |
| 1099 | if (!adjust_pool_surplus(h, 1)) |
| 1100 | break; |
| 1101 | } |
| 1102 | out: |
| 1103 | ret = persistent_huge_pages(h); |
| 1104 | spin_unlock(&hugetlb_lock); |
| 1105 | return ret; |
| 1106 | } |
| 1107 | |
| 1108 | int hugetlb_sysctl_handler(struct ctl_table *table, int write, |
| 1109 | struct file *file, void __user *buffer, |
| 1110 | size_t *length, loff_t *ppos) |
| 1111 | { |
| 1112 | struct hstate *h = &default_hstate; |
| 1113 | unsigned long tmp; |
| 1114 | |
| 1115 | if (!write) |
| 1116 | tmp = h->max_huge_pages; |
| 1117 | |
| 1118 | table->data = &tmp; |
| 1119 | table->maxlen = sizeof(unsigned long); |
| 1120 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| 1121 | |
| 1122 | if (write) |
| 1123 | h->max_huge_pages = set_max_huge_pages(h, tmp); |
| 1124 | |
| 1125 | return 0; |
| 1126 | } |
| 1127 | |
| 1128 | int hugetlb_treat_movable_handler(struct ctl_table *table, int write, |
| 1129 | struct file *file, void __user *buffer, |
| 1130 | size_t *length, loff_t *ppos) |
| 1131 | { |
| 1132 | proc_dointvec(table, write, file, buffer, length, ppos); |
| 1133 | if (hugepages_treat_as_movable) |
| 1134 | htlb_alloc_mask = GFP_HIGHUSER_MOVABLE; |
| 1135 | else |
| 1136 | htlb_alloc_mask = GFP_HIGHUSER; |
| 1137 | return 0; |
| 1138 | } |
| 1139 | |
| 1140 | int hugetlb_overcommit_handler(struct ctl_table *table, int write, |
| 1141 | struct file *file, void __user *buffer, |
| 1142 | size_t *length, loff_t *ppos) |
| 1143 | { |
| 1144 | struct hstate *h = &default_hstate; |
| 1145 | unsigned long tmp; |
| 1146 | |
| 1147 | if (!write) |
| 1148 | tmp = h->nr_overcommit_huge_pages; |
| 1149 | |
| 1150 | table->data = &tmp; |
| 1151 | table->maxlen = sizeof(unsigned long); |
| 1152 | proc_doulongvec_minmax(table, write, file, buffer, length, ppos); |
| 1153 | |
| 1154 | if (write) { |
| 1155 | spin_lock(&hugetlb_lock); |
| 1156 | h->nr_overcommit_huge_pages = tmp; |
| 1157 | spin_unlock(&hugetlb_lock); |
| 1158 | } |
| 1159 | |
| 1160 | return 0; |
| 1161 | } |
| 1162 | |
| 1163 | #endif /* CONFIG_SYSCTL */ |
| 1164 | |
| 1165 | int hugetlb_report_meminfo(char *buf) |
| 1166 | { |
| 1167 | struct hstate *h = &default_hstate; |
| 1168 | return sprintf(buf, |
| 1169 | "HugePages_Total: %5lu\n" |
| 1170 | "HugePages_Free: %5lu\n" |
| 1171 | "HugePages_Rsvd: %5lu\n" |
| 1172 | "HugePages_Surp: %5lu\n" |
| 1173 | "Hugepagesize: %5lu kB\n", |
| 1174 | h->nr_huge_pages, |
| 1175 | h->free_huge_pages, |
| 1176 | h->resv_huge_pages, |
| 1177 | h->surplus_huge_pages, |
| 1178 | 1UL << (huge_page_order(h) + PAGE_SHIFT - 10)); |
| 1179 | } |
| 1180 | |
| 1181 | int hugetlb_report_node_meminfo(int nid, char *buf) |
| 1182 | { |
| 1183 | struct hstate *h = &default_hstate; |
| 1184 | return sprintf(buf, |
| 1185 | "Node %d HugePages_Total: %5u\n" |
| 1186 | "Node %d HugePages_Free: %5u\n" |
| 1187 | "Node %d HugePages_Surp: %5u\n", |
| 1188 | nid, h->nr_huge_pages_node[nid], |
| 1189 | nid, h->free_huge_pages_node[nid], |
| 1190 | nid, h->surplus_huge_pages_node[nid]); |
| 1191 | } |
| 1192 | |
| 1193 | /* Return the number pages of memory we physically have, in PAGE_SIZE units. */ |
| 1194 | unsigned long hugetlb_total_pages(void) |
| 1195 | { |
| 1196 | struct hstate *h = &default_hstate; |
| 1197 | return h->nr_huge_pages * pages_per_huge_page(h); |
| 1198 | } |
| 1199 | |
| 1200 | static int hugetlb_acct_memory(struct hstate *h, long delta) |
| 1201 | { |
| 1202 | int ret = -ENOMEM; |
| 1203 | |
| 1204 | spin_lock(&hugetlb_lock); |
| 1205 | /* |
| 1206 | * When cpuset is configured, it breaks the strict hugetlb page |
| 1207 | * reservation as the accounting is done on a global variable. Such |
| 1208 | * reservation is completely rubbish in the presence of cpuset because |
| 1209 | * the reservation is not checked against page availability for the |
| 1210 | * current cpuset. Application can still potentially OOM'ed by kernel |
| 1211 | * with lack of free htlb page in cpuset that the task is in. |
| 1212 | * Attempt to enforce strict accounting with cpuset is almost |
| 1213 | * impossible (or too ugly) because cpuset is too fluid that |
| 1214 | * task or memory node can be dynamically moved between cpusets. |
| 1215 | * |
| 1216 | * The change of semantics for shared hugetlb mapping with cpuset is |
| 1217 | * undesirable. However, in order to preserve some of the semantics, |
| 1218 | * we fall back to check against current free page availability as |
| 1219 | * a best attempt and hopefully to minimize the impact of changing |
| 1220 | * semantics that cpuset has. |
| 1221 | */ |
| 1222 | if (delta > 0) { |
| 1223 | if (gather_surplus_pages(h, delta) < 0) |
| 1224 | goto out; |
| 1225 | |
| 1226 | if (delta > cpuset_mems_nr(h->free_huge_pages_node)) { |
| 1227 | return_unused_surplus_pages(h, delta); |
| 1228 | goto out; |
| 1229 | } |
| 1230 | } |
| 1231 | |
| 1232 | ret = 0; |
| 1233 | if (delta < 0) |
| 1234 | return_unused_surplus_pages(h, (unsigned long) -delta); |
| 1235 | |
| 1236 | out: |
| 1237 | spin_unlock(&hugetlb_lock); |
| 1238 | return ret; |
| 1239 | } |
| 1240 | |
| 1241 | static void hugetlb_vm_op_open(struct vm_area_struct *vma) |
| 1242 | { |
| 1243 | struct resv_map *reservations = vma_resv_map(vma); |
| 1244 | |
| 1245 | /* |
| 1246 | * This new VMA should share its siblings reservation map if present. |
| 1247 | * The VMA will only ever have a valid reservation map pointer where |
| 1248 | * it is being copied for another still existing VMA. As that VMA |
| 1249 | * has a reference to the reservation map it cannot dissappear until |
| 1250 | * after this open call completes. It is therefore safe to take a |
| 1251 | * new reference here without additional locking. |
| 1252 | */ |
| 1253 | if (reservations) |
| 1254 | kref_get(&reservations->refs); |
| 1255 | } |
| 1256 | |
| 1257 | static void hugetlb_vm_op_close(struct vm_area_struct *vma) |
| 1258 | { |
| 1259 | struct hstate *h = hstate_vma(vma); |
| 1260 | struct resv_map *reservations = vma_resv_map(vma); |
| 1261 | unsigned long reserve; |
| 1262 | unsigned long start; |
| 1263 | unsigned long end; |
| 1264 | |
| 1265 | if (reservations) { |
| 1266 | start = vma_hugecache_offset(h, vma, vma->vm_start); |
| 1267 | end = vma_hugecache_offset(h, vma, vma->vm_end); |
| 1268 | |
| 1269 | reserve = (end - start) - |
| 1270 | region_count(&reservations->regions, start, end); |
| 1271 | |
| 1272 | kref_put(&reservations->refs, resv_map_release); |
| 1273 | |
| 1274 | if (reserve) |
| 1275 | hugetlb_acct_memory(h, -reserve); |
| 1276 | } |
| 1277 | } |
| 1278 | |
| 1279 | /* |
| 1280 | * We cannot handle pagefaults against hugetlb pages at all. They cause |
| 1281 | * handle_mm_fault() to try to instantiate regular-sized pages in the |
| 1282 | * hugegpage VMA. do_page_fault() is supposed to trap this, so BUG is we get |
| 1283 | * this far. |
| 1284 | */ |
| 1285 | static int hugetlb_vm_op_fault(struct vm_area_struct *vma, struct vm_fault *vmf) |
| 1286 | { |
| 1287 | BUG(); |
| 1288 | return 0; |
| 1289 | } |
| 1290 | |
| 1291 | struct vm_operations_struct hugetlb_vm_ops = { |
| 1292 | .fault = hugetlb_vm_op_fault, |
| 1293 | .open = hugetlb_vm_op_open, |
| 1294 | .close = hugetlb_vm_op_close, |
| 1295 | }; |
| 1296 | |
| 1297 | static pte_t make_huge_pte(struct vm_area_struct *vma, struct page *page, |
| 1298 | int writable) |
| 1299 | { |
| 1300 | pte_t entry; |
| 1301 | |
| 1302 | if (writable) { |
| 1303 | entry = |
| 1304 | pte_mkwrite(pte_mkdirty(mk_pte(page, vma->vm_page_prot))); |
| 1305 | } else { |
| 1306 | entry = huge_pte_wrprotect(mk_pte(page, vma->vm_page_prot)); |
| 1307 | } |
| 1308 | entry = pte_mkyoung(entry); |
| 1309 | entry = pte_mkhuge(entry); |
| 1310 | |
| 1311 | return entry; |
| 1312 | } |
| 1313 | |
| 1314 | static void set_huge_ptep_writable(struct vm_area_struct *vma, |
| 1315 | unsigned long address, pte_t *ptep) |
| 1316 | { |
| 1317 | pte_t entry; |
| 1318 | |
| 1319 | entry = pte_mkwrite(pte_mkdirty(huge_ptep_get(ptep))); |
| 1320 | if (huge_ptep_set_access_flags(vma, address, ptep, entry, 1)) { |
| 1321 | update_mmu_cache(vma, address, entry); |
| 1322 | } |
| 1323 | } |
| 1324 | |
| 1325 | |
| 1326 | int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, |
| 1327 | struct vm_area_struct *vma) |
| 1328 | { |
| 1329 | pte_t *src_pte, *dst_pte, entry; |
| 1330 | struct page *ptepage; |
| 1331 | unsigned long addr; |
| 1332 | int cow; |
| 1333 | struct hstate *h = hstate_vma(vma); |
| 1334 | unsigned long sz = huge_page_size(h); |
| 1335 | |
| 1336 | cow = (vma->vm_flags & (VM_SHARED | VM_MAYWRITE)) == VM_MAYWRITE; |
| 1337 | |
| 1338 | for (addr = vma->vm_start; addr < vma->vm_end; addr += sz) { |
| 1339 | src_pte = huge_pte_offset(src, addr); |
| 1340 | if (!src_pte) |
| 1341 | continue; |
| 1342 | dst_pte = huge_pte_alloc(dst, addr, sz); |
| 1343 | if (!dst_pte) |
| 1344 | goto nomem; |
| 1345 | |
| 1346 | /* If the pagetables are shared don't copy or take references */ |
| 1347 | if (dst_pte == src_pte) |
| 1348 | continue; |
| 1349 | |
| 1350 | spin_lock(&dst->page_table_lock); |
| 1351 | spin_lock_nested(&src->page_table_lock, SINGLE_DEPTH_NESTING); |
| 1352 | if (!huge_pte_none(huge_ptep_get(src_pte))) { |
| 1353 | if (cow) |
| 1354 | huge_ptep_set_wrprotect(src, addr, src_pte); |
| 1355 | entry = huge_ptep_get(src_pte); |
| 1356 | ptepage = pte_page(entry); |
| 1357 | get_page(ptepage); |
| 1358 | set_huge_pte_at(dst, addr, dst_pte, entry); |
| 1359 | } |
| 1360 | spin_unlock(&src->page_table_lock); |
| 1361 | spin_unlock(&dst->page_table_lock); |
| 1362 | } |
| 1363 | return 0; |
| 1364 | |
| 1365 | nomem: |
| 1366 | return -ENOMEM; |
| 1367 | } |
| 1368 | |
| 1369 | void __unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| 1370 | unsigned long end, struct page *ref_page) |
| 1371 | { |
| 1372 | struct mm_struct *mm = vma->vm_mm; |
| 1373 | unsigned long address; |
| 1374 | pte_t *ptep; |
| 1375 | pte_t pte; |
| 1376 | struct page *page; |
| 1377 | struct page *tmp; |
| 1378 | struct hstate *h = hstate_vma(vma); |
| 1379 | unsigned long sz = huge_page_size(h); |
| 1380 | |
| 1381 | /* |
| 1382 | * A page gathering list, protected by per file i_mmap_lock. The |
| 1383 | * lock is used to avoid list corruption from multiple unmapping |
| 1384 | * of the same page since we are using page->lru. |
| 1385 | */ |
| 1386 | LIST_HEAD(page_list); |
| 1387 | |
| 1388 | WARN_ON(!is_vm_hugetlb_page(vma)); |
| 1389 | BUG_ON(start & ~huge_page_mask(h)); |
| 1390 | BUG_ON(end & ~huge_page_mask(h)); |
| 1391 | |
| 1392 | spin_lock(&mm->page_table_lock); |
| 1393 | for (address = start; address < end; address += sz) { |
| 1394 | ptep = huge_pte_offset(mm, address); |
| 1395 | if (!ptep) |
| 1396 | continue; |
| 1397 | |
| 1398 | if (huge_pmd_unshare(mm, &address, ptep)) |
| 1399 | continue; |
| 1400 | |
| 1401 | /* |
| 1402 | * If a reference page is supplied, it is because a specific |
| 1403 | * page is being unmapped, not a range. Ensure the page we |
| 1404 | * are about to unmap is the actual page of interest. |
| 1405 | */ |
| 1406 | if (ref_page) { |
| 1407 | pte = huge_ptep_get(ptep); |
| 1408 | if (huge_pte_none(pte)) |
| 1409 | continue; |
| 1410 | page = pte_page(pte); |
| 1411 | if (page != ref_page) |
| 1412 | continue; |
| 1413 | |
| 1414 | /* |
| 1415 | * Mark the VMA as having unmapped its page so that |
| 1416 | * future faults in this VMA will fail rather than |
| 1417 | * looking like data was lost |
| 1418 | */ |
| 1419 | set_vma_resv_flags(vma, HPAGE_RESV_UNMAPPED); |
| 1420 | } |
| 1421 | |
| 1422 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
| 1423 | if (huge_pte_none(pte)) |
| 1424 | continue; |
| 1425 | |
| 1426 | page = pte_page(pte); |
| 1427 | if (pte_dirty(pte)) |
| 1428 | set_page_dirty(page); |
| 1429 | list_add(&page->lru, &page_list); |
| 1430 | } |
| 1431 | spin_unlock(&mm->page_table_lock); |
| 1432 | flush_tlb_range(vma, start, end); |
| 1433 | list_for_each_entry_safe(page, tmp, &page_list, lru) { |
| 1434 | list_del(&page->lru); |
| 1435 | put_page(page); |
| 1436 | } |
| 1437 | } |
| 1438 | |
| 1439 | void unmap_hugepage_range(struct vm_area_struct *vma, unsigned long start, |
| 1440 | unsigned long end, struct page *ref_page) |
| 1441 | { |
| 1442 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
| 1443 | __unmap_hugepage_range(vma, start, end, ref_page); |
| 1444 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| 1445 | } |
| 1446 | |
| 1447 | /* |
| 1448 | * This is called when the original mapper is failing to COW a MAP_PRIVATE |
| 1449 | * mappping it owns the reserve page for. The intention is to unmap the page |
| 1450 | * from other VMAs and let the children be SIGKILLed if they are faulting the |
| 1451 | * same region. |
| 1452 | */ |
| 1453 | int unmap_ref_private(struct mm_struct *mm, |
| 1454 | struct vm_area_struct *vma, |
| 1455 | struct page *page, |
| 1456 | unsigned long address) |
| 1457 | { |
| 1458 | struct vm_area_struct *iter_vma; |
| 1459 | struct address_space *mapping; |
| 1460 | struct prio_tree_iter iter; |
| 1461 | pgoff_t pgoff; |
| 1462 | |
| 1463 | /* |
| 1464 | * vm_pgoff is in PAGE_SIZE units, hence the different calculation |
| 1465 | * from page cache lookup which is in HPAGE_SIZE units. |
| 1466 | */ |
| 1467 | address = address & huge_page_mask(hstate_vma(vma)); |
| 1468 | pgoff = ((address - vma->vm_start) >> PAGE_SHIFT) |
| 1469 | + (vma->vm_pgoff >> PAGE_SHIFT); |
| 1470 | mapping = (struct address_space *)page_private(page); |
| 1471 | |
| 1472 | vma_prio_tree_foreach(iter_vma, &iter, &mapping->i_mmap, pgoff, pgoff) { |
| 1473 | /* Do not unmap the current VMA */ |
| 1474 | if (iter_vma == vma) |
| 1475 | continue; |
| 1476 | |
| 1477 | /* |
| 1478 | * Unmap the page from other VMAs without their own reserves. |
| 1479 | * They get marked to be SIGKILLed if they fault in these |
| 1480 | * areas. This is because a future no-page fault on this VMA |
| 1481 | * could insert a zeroed page instead of the data existing |
| 1482 | * from the time of fork. This would look like data corruption |
| 1483 | */ |
| 1484 | if (!is_vma_resv_set(iter_vma, HPAGE_RESV_OWNER)) |
| 1485 | unmap_hugepage_range(iter_vma, |
| 1486 | address, address + HPAGE_SIZE, |
| 1487 | page); |
| 1488 | } |
| 1489 | |
| 1490 | return 1; |
| 1491 | } |
| 1492 | |
| 1493 | static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1494 | unsigned long address, pte_t *ptep, pte_t pte, |
| 1495 | struct page *pagecache_page) |
| 1496 | { |
| 1497 | struct hstate *h = hstate_vma(vma); |
| 1498 | struct page *old_page, *new_page; |
| 1499 | int avoidcopy; |
| 1500 | int outside_reserve = 0; |
| 1501 | |
| 1502 | old_page = pte_page(pte); |
| 1503 | |
| 1504 | retry_avoidcopy: |
| 1505 | /* If no-one else is actually using this page, avoid the copy |
| 1506 | * and just make the page writable */ |
| 1507 | avoidcopy = (page_count(old_page) == 1); |
| 1508 | if (avoidcopy) { |
| 1509 | set_huge_ptep_writable(vma, address, ptep); |
| 1510 | return 0; |
| 1511 | } |
| 1512 | |
| 1513 | /* |
| 1514 | * If the process that created a MAP_PRIVATE mapping is about to |
| 1515 | * perform a COW due to a shared page count, attempt to satisfy |
| 1516 | * the allocation without using the existing reserves. The pagecache |
| 1517 | * page is used to determine if the reserve at this address was |
| 1518 | * consumed or not. If reserves were used, a partial faulted mapping |
| 1519 | * at the time of fork() could consume its reserves on COW instead |
| 1520 | * of the full address range. |
| 1521 | */ |
| 1522 | if (!(vma->vm_flags & VM_SHARED) && |
| 1523 | is_vma_resv_set(vma, HPAGE_RESV_OWNER) && |
| 1524 | old_page != pagecache_page) |
| 1525 | outside_reserve = 1; |
| 1526 | |
| 1527 | page_cache_get(old_page); |
| 1528 | new_page = alloc_huge_page(vma, address, outside_reserve); |
| 1529 | |
| 1530 | if (IS_ERR(new_page)) { |
| 1531 | page_cache_release(old_page); |
| 1532 | |
| 1533 | /* |
| 1534 | * If a process owning a MAP_PRIVATE mapping fails to COW, |
| 1535 | * it is due to references held by a child and an insufficient |
| 1536 | * huge page pool. To guarantee the original mappers |
| 1537 | * reliability, unmap the page from child processes. The child |
| 1538 | * may get SIGKILLed if it later faults. |
| 1539 | */ |
| 1540 | if (outside_reserve) { |
| 1541 | BUG_ON(huge_pte_none(pte)); |
| 1542 | if (unmap_ref_private(mm, vma, old_page, address)) { |
| 1543 | BUG_ON(page_count(old_page) != 1); |
| 1544 | BUG_ON(huge_pte_none(pte)); |
| 1545 | goto retry_avoidcopy; |
| 1546 | } |
| 1547 | WARN_ON_ONCE(1); |
| 1548 | } |
| 1549 | |
| 1550 | return -PTR_ERR(new_page); |
| 1551 | } |
| 1552 | |
| 1553 | spin_unlock(&mm->page_table_lock); |
| 1554 | copy_huge_page(new_page, old_page, address, vma); |
| 1555 | __SetPageUptodate(new_page); |
| 1556 | spin_lock(&mm->page_table_lock); |
| 1557 | |
| 1558 | ptep = huge_pte_offset(mm, address & huge_page_mask(h)); |
| 1559 | if (likely(pte_same(huge_ptep_get(ptep), pte))) { |
| 1560 | /* Break COW */ |
| 1561 | huge_ptep_clear_flush(vma, address, ptep); |
| 1562 | set_huge_pte_at(mm, address, ptep, |
| 1563 | make_huge_pte(vma, new_page, 1)); |
| 1564 | /* Make the old page be freed below */ |
| 1565 | new_page = old_page; |
| 1566 | } |
| 1567 | page_cache_release(new_page); |
| 1568 | page_cache_release(old_page); |
| 1569 | return 0; |
| 1570 | } |
| 1571 | |
| 1572 | /* Return the pagecache page at a given address within a VMA */ |
| 1573 | static struct page *hugetlbfs_pagecache_page(struct hstate *h, |
| 1574 | struct vm_area_struct *vma, unsigned long address) |
| 1575 | { |
| 1576 | struct address_space *mapping; |
| 1577 | pgoff_t idx; |
| 1578 | |
| 1579 | mapping = vma->vm_file->f_mapping; |
| 1580 | idx = vma_hugecache_offset(h, vma, address); |
| 1581 | |
| 1582 | return find_lock_page(mapping, idx); |
| 1583 | } |
| 1584 | |
| 1585 | static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1586 | unsigned long address, pte_t *ptep, int write_access) |
| 1587 | { |
| 1588 | struct hstate *h = hstate_vma(vma); |
| 1589 | int ret = VM_FAULT_SIGBUS; |
| 1590 | pgoff_t idx; |
| 1591 | unsigned long size; |
| 1592 | struct page *page; |
| 1593 | struct address_space *mapping; |
| 1594 | pte_t new_pte; |
| 1595 | |
| 1596 | /* |
| 1597 | * Currently, we are forced to kill the process in the event the |
| 1598 | * original mapper has unmapped pages from the child due to a failed |
| 1599 | * COW. Warn that such a situation has occured as it may not be obvious |
| 1600 | */ |
| 1601 | if (is_vma_resv_set(vma, HPAGE_RESV_UNMAPPED)) { |
| 1602 | printk(KERN_WARNING |
| 1603 | "PID %d killed due to inadequate hugepage pool\n", |
| 1604 | current->pid); |
| 1605 | return ret; |
| 1606 | } |
| 1607 | |
| 1608 | mapping = vma->vm_file->f_mapping; |
| 1609 | idx = vma_hugecache_offset(h, vma, address); |
| 1610 | |
| 1611 | /* |
| 1612 | * Use page lock to guard against racing truncation |
| 1613 | * before we get page_table_lock. |
| 1614 | */ |
| 1615 | retry: |
| 1616 | page = find_lock_page(mapping, idx); |
| 1617 | if (!page) { |
| 1618 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
| 1619 | if (idx >= size) |
| 1620 | goto out; |
| 1621 | page = alloc_huge_page(vma, address, 0); |
| 1622 | if (IS_ERR(page)) { |
| 1623 | ret = -PTR_ERR(page); |
| 1624 | goto out; |
| 1625 | } |
| 1626 | clear_huge_page(page, address, huge_page_size(h)); |
| 1627 | __SetPageUptodate(page); |
| 1628 | |
| 1629 | if (vma->vm_flags & VM_SHARED) { |
| 1630 | int err; |
| 1631 | struct inode *inode = mapping->host; |
| 1632 | |
| 1633 | err = add_to_page_cache(page, mapping, idx, GFP_KERNEL); |
| 1634 | if (err) { |
| 1635 | put_page(page); |
| 1636 | if (err == -EEXIST) |
| 1637 | goto retry; |
| 1638 | goto out; |
| 1639 | } |
| 1640 | |
| 1641 | spin_lock(&inode->i_lock); |
| 1642 | inode->i_blocks += blocks_per_huge_page(h); |
| 1643 | spin_unlock(&inode->i_lock); |
| 1644 | } else |
| 1645 | lock_page(page); |
| 1646 | } |
| 1647 | |
| 1648 | spin_lock(&mm->page_table_lock); |
| 1649 | size = i_size_read(mapping->host) >> huge_page_shift(h); |
| 1650 | if (idx >= size) |
| 1651 | goto backout; |
| 1652 | |
| 1653 | ret = 0; |
| 1654 | if (!huge_pte_none(huge_ptep_get(ptep))) |
| 1655 | goto backout; |
| 1656 | |
| 1657 | new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE) |
| 1658 | && (vma->vm_flags & VM_SHARED))); |
| 1659 | set_huge_pte_at(mm, address, ptep, new_pte); |
| 1660 | |
| 1661 | if (write_access && !(vma->vm_flags & VM_SHARED)) { |
| 1662 | /* Optimization, do the COW without a second fault */ |
| 1663 | ret = hugetlb_cow(mm, vma, address, ptep, new_pte, page); |
| 1664 | } |
| 1665 | |
| 1666 | spin_unlock(&mm->page_table_lock); |
| 1667 | unlock_page(page); |
| 1668 | out: |
| 1669 | return ret; |
| 1670 | |
| 1671 | backout: |
| 1672 | spin_unlock(&mm->page_table_lock); |
| 1673 | unlock_page(page); |
| 1674 | put_page(page); |
| 1675 | goto out; |
| 1676 | } |
| 1677 | |
| 1678 | int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1679 | unsigned long address, int write_access) |
| 1680 | { |
| 1681 | pte_t *ptep; |
| 1682 | pte_t entry; |
| 1683 | int ret; |
| 1684 | static DEFINE_MUTEX(hugetlb_instantiation_mutex); |
| 1685 | struct hstate *h = hstate_vma(vma); |
| 1686 | |
| 1687 | ptep = huge_pte_alloc(mm, address, huge_page_size(h)); |
| 1688 | if (!ptep) |
| 1689 | return VM_FAULT_OOM; |
| 1690 | |
| 1691 | /* |
| 1692 | * Serialize hugepage allocation and instantiation, so that we don't |
| 1693 | * get spurious allocation failures if two CPUs race to instantiate |
| 1694 | * the same page in the page cache. |
| 1695 | */ |
| 1696 | mutex_lock(&hugetlb_instantiation_mutex); |
| 1697 | entry = huge_ptep_get(ptep); |
| 1698 | if (huge_pte_none(entry)) { |
| 1699 | ret = hugetlb_no_page(mm, vma, address, ptep, write_access); |
| 1700 | mutex_unlock(&hugetlb_instantiation_mutex); |
| 1701 | return ret; |
| 1702 | } |
| 1703 | |
| 1704 | ret = 0; |
| 1705 | |
| 1706 | spin_lock(&mm->page_table_lock); |
| 1707 | /* Check for a racing update before calling hugetlb_cow */ |
| 1708 | if (likely(pte_same(entry, huge_ptep_get(ptep)))) |
| 1709 | if (write_access && !pte_write(entry)) { |
| 1710 | struct page *page; |
| 1711 | page = hugetlbfs_pagecache_page(h, vma, address); |
| 1712 | ret = hugetlb_cow(mm, vma, address, ptep, entry, page); |
| 1713 | if (page) { |
| 1714 | unlock_page(page); |
| 1715 | put_page(page); |
| 1716 | } |
| 1717 | } |
| 1718 | spin_unlock(&mm->page_table_lock); |
| 1719 | mutex_unlock(&hugetlb_instantiation_mutex); |
| 1720 | |
| 1721 | return ret; |
| 1722 | } |
| 1723 | |
| 1724 | int follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, |
| 1725 | struct page **pages, struct vm_area_struct **vmas, |
| 1726 | unsigned long *position, int *length, int i, |
| 1727 | int write) |
| 1728 | { |
| 1729 | unsigned long pfn_offset; |
| 1730 | unsigned long vaddr = *position; |
| 1731 | int remainder = *length; |
| 1732 | struct hstate *h = hstate_vma(vma); |
| 1733 | |
| 1734 | spin_lock(&mm->page_table_lock); |
| 1735 | while (vaddr < vma->vm_end && remainder) { |
| 1736 | pte_t *pte; |
| 1737 | struct page *page; |
| 1738 | |
| 1739 | /* |
| 1740 | * Some archs (sparc64, sh*) have multiple pte_ts to |
| 1741 | * each hugepage. We have to make * sure we get the |
| 1742 | * first, for the page indexing below to work. |
| 1743 | */ |
| 1744 | pte = huge_pte_offset(mm, vaddr & huge_page_mask(h)); |
| 1745 | |
| 1746 | if (!pte || huge_pte_none(huge_ptep_get(pte)) || |
| 1747 | (write && !pte_write(huge_ptep_get(pte)))) { |
| 1748 | int ret; |
| 1749 | |
| 1750 | spin_unlock(&mm->page_table_lock); |
| 1751 | ret = hugetlb_fault(mm, vma, vaddr, write); |
| 1752 | spin_lock(&mm->page_table_lock); |
| 1753 | if (!(ret & VM_FAULT_ERROR)) |
| 1754 | continue; |
| 1755 | |
| 1756 | remainder = 0; |
| 1757 | if (!i) |
| 1758 | i = -EFAULT; |
| 1759 | break; |
| 1760 | } |
| 1761 | |
| 1762 | pfn_offset = (vaddr & ~huge_page_mask(h)) >> PAGE_SHIFT; |
| 1763 | page = pte_page(huge_ptep_get(pte)); |
| 1764 | same_page: |
| 1765 | if (pages) { |
| 1766 | get_page(page); |
| 1767 | pages[i] = page + pfn_offset; |
| 1768 | } |
| 1769 | |
| 1770 | if (vmas) |
| 1771 | vmas[i] = vma; |
| 1772 | |
| 1773 | vaddr += PAGE_SIZE; |
| 1774 | ++pfn_offset; |
| 1775 | --remainder; |
| 1776 | ++i; |
| 1777 | if (vaddr < vma->vm_end && remainder && |
| 1778 | pfn_offset < pages_per_huge_page(h)) { |
| 1779 | /* |
| 1780 | * We use pfn_offset to avoid touching the pageframes |
| 1781 | * of this compound page. |
| 1782 | */ |
| 1783 | goto same_page; |
| 1784 | } |
| 1785 | } |
| 1786 | spin_unlock(&mm->page_table_lock); |
| 1787 | *length = remainder; |
| 1788 | *position = vaddr; |
| 1789 | |
| 1790 | return i; |
| 1791 | } |
| 1792 | |
| 1793 | void hugetlb_change_protection(struct vm_area_struct *vma, |
| 1794 | unsigned long address, unsigned long end, pgprot_t newprot) |
| 1795 | { |
| 1796 | struct mm_struct *mm = vma->vm_mm; |
| 1797 | unsigned long start = address; |
| 1798 | pte_t *ptep; |
| 1799 | pte_t pte; |
| 1800 | struct hstate *h = hstate_vma(vma); |
| 1801 | |
| 1802 | BUG_ON(address >= end); |
| 1803 | flush_cache_range(vma, address, end); |
| 1804 | |
| 1805 | spin_lock(&vma->vm_file->f_mapping->i_mmap_lock); |
| 1806 | spin_lock(&mm->page_table_lock); |
| 1807 | for (; address < end; address += huge_page_size(h)) { |
| 1808 | ptep = huge_pte_offset(mm, address); |
| 1809 | if (!ptep) |
| 1810 | continue; |
| 1811 | if (huge_pmd_unshare(mm, &address, ptep)) |
| 1812 | continue; |
| 1813 | if (!huge_pte_none(huge_ptep_get(ptep))) { |
| 1814 | pte = huge_ptep_get_and_clear(mm, address, ptep); |
| 1815 | pte = pte_mkhuge(pte_modify(pte, newprot)); |
| 1816 | set_huge_pte_at(mm, address, ptep, pte); |
| 1817 | } |
| 1818 | } |
| 1819 | spin_unlock(&mm->page_table_lock); |
| 1820 | spin_unlock(&vma->vm_file->f_mapping->i_mmap_lock); |
| 1821 | |
| 1822 | flush_tlb_range(vma, start, end); |
| 1823 | } |
| 1824 | |
| 1825 | int hugetlb_reserve_pages(struct inode *inode, |
| 1826 | long from, long to, |
| 1827 | struct vm_area_struct *vma) |
| 1828 | { |
| 1829 | long ret, chg; |
| 1830 | struct hstate *h = hstate_inode(inode); |
| 1831 | |
| 1832 | if (vma && vma->vm_flags & VM_NORESERVE) |
| 1833 | return 0; |
| 1834 | |
| 1835 | /* |
| 1836 | * Shared mappings base their reservation on the number of pages that |
| 1837 | * are already allocated on behalf of the file. Private mappings need |
| 1838 | * to reserve the full area even if read-only as mprotect() may be |
| 1839 | * called to make the mapping read-write. Assume !vma is a shm mapping |
| 1840 | */ |
| 1841 | if (!vma || vma->vm_flags & VM_SHARED) |
| 1842 | chg = region_chg(&inode->i_mapping->private_list, from, to); |
| 1843 | else { |
| 1844 | struct resv_map *resv_map = resv_map_alloc(); |
| 1845 | if (!resv_map) |
| 1846 | return -ENOMEM; |
| 1847 | |
| 1848 | chg = to - from; |
| 1849 | |
| 1850 | set_vma_resv_map(vma, resv_map); |
| 1851 | set_vma_resv_flags(vma, HPAGE_RESV_OWNER); |
| 1852 | } |
| 1853 | |
| 1854 | if (chg < 0) |
| 1855 | return chg; |
| 1856 | |
| 1857 | if (hugetlb_get_quota(inode->i_mapping, chg)) |
| 1858 | return -ENOSPC; |
| 1859 | ret = hugetlb_acct_memory(h, chg); |
| 1860 | if (ret < 0) { |
| 1861 | hugetlb_put_quota(inode->i_mapping, chg); |
| 1862 | return ret; |
| 1863 | } |
| 1864 | if (!vma || vma->vm_flags & VM_SHARED) |
| 1865 | region_add(&inode->i_mapping->private_list, from, to); |
| 1866 | return 0; |
| 1867 | } |
| 1868 | |
| 1869 | void hugetlb_unreserve_pages(struct inode *inode, long offset, long freed) |
| 1870 | { |
| 1871 | struct hstate *h = hstate_inode(inode); |
| 1872 | long chg = region_truncate(&inode->i_mapping->private_list, offset); |
| 1873 | |
| 1874 | spin_lock(&inode->i_lock); |
| 1875 | inode->i_blocks -= blocks_per_huge_page(h); |
| 1876 | spin_unlock(&inode->i_lock); |
| 1877 | |
| 1878 | hugetlb_put_quota(inode->i_mapping, (chg - freed)); |
| 1879 | hugetlb_acct_memory(h, -(chg - freed)); |
| 1880 | } |