| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | /* |
| 3 | * SLUB: A slab allocator that limits cache line use instead of queuing |
| 4 | * objects in per cpu and per node lists. |
| 5 | * |
| 6 | * The allocator synchronizes using per slab locks or atomic operatios |
| 7 | * and only uses a centralized lock to manage a pool of partial slabs. |
| 8 | * |
| 9 | * (C) 2007 SGI, Christoph Lameter |
| 10 | * (C) 2011 Linux Foundation, Christoph Lameter |
| 11 | */ |
| 12 | |
| 13 | #include <linux/mm.h> |
| 14 | #include <linux/swap.h> /* struct reclaim_state */ |
| 15 | #include <linux/module.h> |
| 16 | #include <linux/bit_spinlock.h> |
| 17 | #include <linux/interrupt.h> |
| 18 | #include <linux/bitops.h> |
| 19 | #include <linux/slab.h> |
| 20 | #include "slab.h" |
| 21 | #include <linux/proc_fs.h> |
| 22 | #include <linux/seq_file.h> |
| 23 | #include <linux/kasan.h> |
| 24 | #include <linux/cpu.h> |
| 25 | #include <linux/cpuset.h> |
| 26 | #include <linux/mempolicy.h> |
| 27 | #include <linux/ctype.h> |
| 28 | #include <linux/debugobjects.h> |
| 29 | #include <linux/kallsyms.h> |
| 30 | #include <linux/memory.h> |
| 31 | #include <linux/math64.h> |
| 32 | #include <linux/fault-inject.h> |
| 33 | #include <linux/stacktrace.h> |
| 34 | #include <linux/prefetch.h> |
| 35 | #include <linux/memcontrol.h> |
| 36 | #include <linux/random.h> |
| 37 | |
| 38 | #include <trace/events/kmem.h> |
| 39 | |
| 40 | #include "internal.h" |
| 41 | |
| 42 | /* |
| 43 | * Lock order: |
| 44 | * 1. slab_mutex (Global Mutex) |
| 45 | * 2. node->list_lock |
| 46 | * 3. slab_lock(page) (Only on some arches and for debugging) |
| 47 | * |
| 48 | * slab_mutex |
| 49 | * |
| 50 | * The role of the slab_mutex is to protect the list of all the slabs |
| 51 | * and to synchronize major metadata changes to slab cache structures. |
| 52 | * |
| 53 | * The slab_lock is only used for debugging and on arches that do not |
| 54 | * have the ability to do a cmpxchg_double. It only protects: |
| 55 | * A. page->freelist -> List of object free in a page |
| 56 | * B. page->inuse -> Number of objects in use |
| 57 | * C. page->objects -> Number of objects in page |
| 58 | * D. page->frozen -> frozen state |
| 59 | * |
| 60 | * If a slab is frozen then it is exempt from list management. It is not |
| 61 | * on any list. The processor that froze the slab is the one who can |
| 62 | * perform list operations on the page. Other processors may put objects |
| 63 | * onto the freelist but the processor that froze the slab is the only |
| 64 | * one that can retrieve the objects from the page's freelist. |
| 65 | * |
| 66 | * The list_lock protects the partial and full list on each node and |
| 67 | * the partial slab counter. If taken then no new slabs may be added or |
| 68 | * removed from the lists nor make the number of partial slabs be modified. |
| 69 | * (Note that the total number of slabs is an atomic value that may be |
| 70 | * modified without taking the list lock). |
| 71 | * |
| 72 | * The list_lock is a centralized lock and thus we avoid taking it as |
| 73 | * much as possible. As long as SLUB does not have to handle partial |
| 74 | * slabs, operations can continue without any centralized lock. F.e. |
| 75 | * allocating a long series of objects that fill up slabs does not require |
| 76 | * the list lock. |
| 77 | * Interrupts are disabled during allocation and deallocation in order to |
| 78 | * make the slab allocator safe to use in the context of an irq. In addition |
| 79 | * interrupts are disabled to ensure that the processor does not change |
| 80 | * while handling per_cpu slabs, due to kernel preemption. |
| 81 | * |
| 82 | * SLUB assigns one slab for allocation to each processor. |
| 83 | * Allocations only occur from these slabs called cpu slabs. |
| 84 | * |
| 85 | * Slabs with free elements are kept on a partial list and during regular |
| 86 | * operations no list for full slabs is used. If an object in a full slab is |
| 87 | * freed then the slab will show up again on the partial lists. |
| 88 | * We track full slabs for debugging purposes though because otherwise we |
| 89 | * cannot scan all objects. |
| 90 | * |
| 91 | * Slabs are freed when they become empty. Teardown and setup is |
| 92 | * minimal so we rely on the page allocators per cpu caches for |
| 93 | * fast frees and allocs. |
| 94 | * |
| 95 | * Overloading of page flags that are otherwise used for LRU management. |
| 96 | * |
| 97 | * PageActive The slab is frozen and exempt from list processing. |
| 98 | * This means that the slab is dedicated to a purpose |
| 99 | * such as satisfying allocations for a specific |
| 100 | * processor. Objects may be freed in the slab while |
| 101 | * it is frozen but slab_free will then skip the usual |
| 102 | * list operations. It is up to the processor holding |
| 103 | * the slab to integrate the slab into the slab lists |
| 104 | * when the slab is no longer needed. |
| 105 | * |
| 106 | * One use of this flag is to mark slabs that are |
| 107 | * used for allocations. Then such a slab becomes a cpu |
| 108 | * slab. The cpu slab may be equipped with an additional |
| 109 | * freelist that allows lockless access to |
| 110 | * free objects in addition to the regular freelist |
| 111 | * that requires the slab lock. |
| 112 | * |
| 113 | * PageError Slab requires special handling due to debug |
| 114 | * options set. This moves slab handling out of |
| 115 | * the fast path and disables lockless freelists. |
| 116 | */ |
| 117 | |
| 118 | static inline int kmem_cache_debug(struct kmem_cache *s) |
| 119 | { |
| 120 | #ifdef CONFIG_SLUB_DEBUG |
| 121 | return unlikely(s->flags & SLAB_DEBUG_FLAGS); |
| 122 | #else |
| 123 | return 0; |
| 124 | #endif |
| 125 | } |
| 126 | |
| 127 | void *fixup_red_left(struct kmem_cache *s, void *p) |
| 128 | { |
| 129 | if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) |
| 130 | p += s->red_left_pad; |
| 131 | |
| 132 | return p; |
| 133 | } |
| 134 | |
| 135 | static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s) |
| 136 | { |
| 137 | #ifdef CONFIG_SLUB_CPU_PARTIAL |
| 138 | return !kmem_cache_debug(s); |
| 139 | #else |
| 140 | return false; |
| 141 | #endif |
| 142 | } |
| 143 | |
| 144 | /* |
| 145 | * Issues still to be resolved: |
| 146 | * |
| 147 | * - Support PAGE_ALLOC_DEBUG. Should be easy to do. |
| 148 | * |
| 149 | * - Variable sizing of the per node arrays |
| 150 | */ |
| 151 | |
| 152 | /* Enable to test recovery from slab corruption on boot */ |
| 153 | #undef SLUB_RESILIENCY_TEST |
| 154 | |
| 155 | /* Enable to log cmpxchg failures */ |
| 156 | #undef SLUB_DEBUG_CMPXCHG |
| 157 | |
| 158 | /* |
| 159 | * Mininum number of partial slabs. These will be left on the partial |
| 160 | * lists even if they are empty. kmem_cache_shrink may reclaim them. |
| 161 | */ |
| 162 | #define MIN_PARTIAL 5 |
| 163 | |
| 164 | /* |
| 165 | * Maximum number of desirable partial slabs. |
| 166 | * The existence of more partial slabs makes kmem_cache_shrink |
| 167 | * sort the partial list by the number of objects in use. |
| 168 | */ |
| 169 | #define MAX_PARTIAL 10 |
| 170 | |
| 171 | #define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \ |
| 172 | SLAB_POISON | SLAB_STORE_USER) |
| 173 | |
| 174 | /* |
| 175 | * These debug flags cannot use CMPXCHG because there might be consistency |
| 176 | * issues when checking or reading debug information |
| 177 | */ |
| 178 | #define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \ |
| 179 | SLAB_TRACE) |
| 180 | |
| 181 | |
| 182 | /* |
| 183 | * Debugging flags that require metadata to be stored in the slab. These get |
| 184 | * disabled when slub_debug=O is used and a cache's min order increases with |
| 185 | * metadata. |
| 186 | */ |
| 187 | #define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) |
| 188 | |
| 189 | #define OO_SHIFT 16 |
| 190 | #define OO_MASK ((1 << OO_SHIFT) - 1) |
| 191 | #define MAX_OBJS_PER_PAGE 32767 /* since page.objects is u15 */ |
| 192 | |
| 193 | /* Internal SLUB flags */ |
| 194 | /* Poison object */ |
| 195 | #define __OBJECT_POISON ((slab_flags_t __force)0x80000000U) |
| 196 | /* Use cmpxchg_double */ |
| 197 | #define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U) |
| 198 | |
| 199 | /* |
| 200 | * Tracking user of a slab. |
| 201 | */ |
| 202 | #define TRACK_ADDRS_COUNT 16 |
| 203 | struct track { |
| 204 | unsigned long addr; /* Called from address */ |
| 205 | #ifdef CONFIG_STACKTRACE |
| 206 | unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */ |
| 207 | #endif |
| 208 | int cpu; /* Was running on cpu */ |
| 209 | int pid; /* Pid context */ |
| 210 | unsigned long when; /* When did the operation occur */ |
| 211 | }; |
| 212 | |
| 213 | enum track_item { TRACK_ALLOC, TRACK_FREE }; |
| 214 | |
| 215 | #ifdef CONFIG_SYSFS |
| 216 | static int sysfs_slab_add(struct kmem_cache *); |
| 217 | static int sysfs_slab_alias(struct kmem_cache *, const char *); |
| 218 | static void memcg_propagate_slab_attrs(struct kmem_cache *s); |
| 219 | static void sysfs_slab_remove(struct kmem_cache *s); |
| 220 | #else |
| 221 | static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; } |
| 222 | static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p) |
| 223 | { return 0; } |
| 224 | static inline void memcg_propagate_slab_attrs(struct kmem_cache *s) { } |
| 225 | static inline void sysfs_slab_remove(struct kmem_cache *s) { } |
| 226 | #endif |
| 227 | |
| 228 | static inline void stat(const struct kmem_cache *s, enum stat_item si) |
| 229 | { |
| 230 | #ifdef CONFIG_SLUB_STATS |
| 231 | /* |
| 232 | * The rmw is racy on a preemptible kernel but this is acceptable, so |
| 233 | * avoid this_cpu_add()'s irq-disable overhead. |
| 234 | */ |
| 235 | raw_cpu_inc(s->cpu_slab->stat[si]); |
| 236 | #endif |
| 237 | } |
| 238 | |
| 239 | /******************************************************************** |
| 240 | * Core slab cache functions |
| 241 | *******************************************************************/ |
| 242 | |
| 243 | /* |
| 244 | * Returns freelist pointer (ptr). With hardening, this is obfuscated |
| 245 | * with an XOR of the address where the pointer is held and a per-cache |
| 246 | * random number. |
| 247 | */ |
| 248 | static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr, |
| 249 | unsigned long ptr_addr) |
| 250 | { |
| 251 | #ifdef CONFIG_SLAB_FREELIST_HARDENED |
| 252 | return (void *)((unsigned long)ptr ^ s->random ^ ptr_addr); |
| 253 | #else |
| 254 | return ptr; |
| 255 | #endif |
| 256 | } |
| 257 | |
| 258 | /* Returns the freelist pointer recorded at location ptr_addr. */ |
| 259 | static inline void *freelist_dereference(const struct kmem_cache *s, |
| 260 | void *ptr_addr) |
| 261 | { |
| 262 | return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr), |
| 263 | (unsigned long)ptr_addr); |
| 264 | } |
| 265 | |
| 266 | static inline void *get_freepointer(struct kmem_cache *s, void *object) |
| 267 | { |
| 268 | return freelist_dereference(s, object + s->offset); |
| 269 | } |
| 270 | |
| 271 | static void prefetch_freepointer(const struct kmem_cache *s, void *object) |
| 272 | { |
| 273 | prefetch(object + s->offset); |
| 274 | } |
| 275 | |
| 276 | static inline void *get_freepointer_safe(struct kmem_cache *s, void *object) |
| 277 | { |
| 278 | unsigned long freepointer_addr; |
| 279 | void *p; |
| 280 | |
| 281 | if (!debug_pagealloc_enabled()) |
| 282 | return get_freepointer(s, object); |
| 283 | |
| 284 | freepointer_addr = (unsigned long)object + s->offset; |
| 285 | probe_kernel_read(&p, (void **)freepointer_addr, sizeof(p)); |
| 286 | return freelist_ptr(s, p, freepointer_addr); |
| 287 | } |
| 288 | |
| 289 | static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp) |
| 290 | { |
| 291 | unsigned long freeptr_addr = (unsigned long)object + s->offset; |
| 292 | |
| 293 | #ifdef CONFIG_SLAB_FREELIST_HARDENED |
| 294 | BUG_ON(object == fp); /* naive detection of double free or corruption */ |
| 295 | #endif |
| 296 | |
| 297 | *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr); |
| 298 | } |
| 299 | |
| 300 | /* Loop over all objects in a slab */ |
| 301 | #define for_each_object(__p, __s, __addr, __objects) \ |
| 302 | for (__p = fixup_red_left(__s, __addr); \ |
| 303 | __p < (__addr) + (__objects) * (__s)->size; \ |
| 304 | __p += (__s)->size) |
| 305 | |
| 306 | #define for_each_object_idx(__p, __idx, __s, __addr, __objects) \ |
| 307 | for (__p = fixup_red_left(__s, __addr), __idx = 1; \ |
| 308 | __idx <= __objects; \ |
| 309 | __p += (__s)->size, __idx++) |
| 310 | |
| 311 | /* Determine object index from a given position */ |
| 312 | static inline unsigned int slab_index(void *p, struct kmem_cache *s, void *addr) |
| 313 | { |
| 314 | return (p - addr) / s->size; |
| 315 | } |
| 316 | |
| 317 | static inline unsigned int order_objects(unsigned int order, unsigned int size) |
| 318 | { |
| 319 | return ((unsigned int)PAGE_SIZE << order) / size; |
| 320 | } |
| 321 | |
| 322 | static inline struct kmem_cache_order_objects oo_make(unsigned int order, |
| 323 | unsigned int size) |
| 324 | { |
| 325 | struct kmem_cache_order_objects x = { |
| 326 | (order << OO_SHIFT) + order_objects(order, size) |
| 327 | }; |
| 328 | |
| 329 | return x; |
| 330 | } |
| 331 | |
| 332 | static inline unsigned int oo_order(struct kmem_cache_order_objects x) |
| 333 | { |
| 334 | return x.x >> OO_SHIFT; |
| 335 | } |
| 336 | |
| 337 | static inline unsigned int oo_objects(struct kmem_cache_order_objects x) |
| 338 | { |
| 339 | return x.x & OO_MASK; |
| 340 | } |
| 341 | |
| 342 | /* |
| 343 | * Per slab locking using the pagelock |
| 344 | */ |
| 345 | static __always_inline void slab_lock(struct page *page) |
| 346 | { |
| 347 | VM_BUG_ON_PAGE(PageTail(page), page); |
| 348 | bit_spin_lock(PG_locked, &page->flags); |
| 349 | } |
| 350 | |
| 351 | static __always_inline void slab_unlock(struct page *page) |
| 352 | { |
| 353 | VM_BUG_ON_PAGE(PageTail(page), page); |
| 354 | __bit_spin_unlock(PG_locked, &page->flags); |
| 355 | } |
| 356 | |
| 357 | /* Interrupts must be disabled (for the fallback code to work right) */ |
| 358 | static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page, |
| 359 | void *freelist_old, unsigned long counters_old, |
| 360 | void *freelist_new, unsigned long counters_new, |
| 361 | const char *n) |
| 362 | { |
| 363 | VM_BUG_ON(!irqs_disabled()); |
| 364 | #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ |
| 365 | defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) |
| 366 | if (s->flags & __CMPXCHG_DOUBLE) { |
| 367 | if (cmpxchg_double(&page->freelist, &page->counters, |
| 368 | freelist_old, counters_old, |
| 369 | freelist_new, counters_new)) |
| 370 | return true; |
| 371 | } else |
| 372 | #endif |
| 373 | { |
| 374 | slab_lock(page); |
| 375 | if (page->freelist == freelist_old && |
| 376 | page->counters == counters_old) { |
| 377 | page->freelist = freelist_new; |
| 378 | page->counters = counters_new; |
| 379 | slab_unlock(page); |
| 380 | return true; |
| 381 | } |
| 382 | slab_unlock(page); |
| 383 | } |
| 384 | |
| 385 | cpu_relax(); |
| 386 | stat(s, CMPXCHG_DOUBLE_FAIL); |
| 387 | |
| 388 | #ifdef SLUB_DEBUG_CMPXCHG |
| 389 | pr_info("%s %s: cmpxchg double redo ", n, s->name); |
| 390 | #endif |
| 391 | |
| 392 | return false; |
| 393 | } |
| 394 | |
| 395 | static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page, |
| 396 | void *freelist_old, unsigned long counters_old, |
| 397 | void *freelist_new, unsigned long counters_new, |
| 398 | const char *n) |
| 399 | { |
| 400 | #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ |
| 401 | defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) |
| 402 | if (s->flags & __CMPXCHG_DOUBLE) { |
| 403 | if (cmpxchg_double(&page->freelist, &page->counters, |
| 404 | freelist_old, counters_old, |
| 405 | freelist_new, counters_new)) |
| 406 | return true; |
| 407 | } else |
| 408 | #endif |
| 409 | { |
| 410 | unsigned long flags; |
| 411 | |
| 412 | local_irq_save(flags); |
| 413 | slab_lock(page); |
| 414 | if (page->freelist == freelist_old && |
| 415 | page->counters == counters_old) { |
| 416 | page->freelist = freelist_new; |
| 417 | page->counters = counters_new; |
| 418 | slab_unlock(page); |
| 419 | local_irq_restore(flags); |
| 420 | return true; |
| 421 | } |
| 422 | slab_unlock(page); |
| 423 | local_irq_restore(flags); |
| 424 | } |
| 425 | |
| 426 | cpu_relax(); |
| 427 | stat(s, CMPXCHG_DOUBLE_FAIL); |
| 428 | |
| 429 | #ifdef SLUB_DEBUG_CMPXCHG |
| 430 | pr_info("%s %s: cmpxchg double redo ", n, s->name); |
| 431 | #endif |
| 432 | |
| 433 | return false; |
| 434 | } |
| 435 | |
| 436 | #ifdef CONFIG_SLUB_DEBUG |
| 437 | /* |
| 438 | * Determine a map of object in use on a page. |
| 439 | * |
| 440 | * Node listlock must be held to guarantee that the page does |
| 441 | * not vanish from under us. |
| 442 | */ |
| 443 | static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map) |
| 444 | { |
| 445 | void *p; |
| 446 | void *addr = page_address(page); |
| 447 | |
| 448 | for (p = page->freelist; p; p = get_freepointer(s, p)) |
| 449 | set_bit(slab_index(p, s, addr), map); |
| 450 | } |
| 451 | |
| 452 | static inline unsigned int size_from_object(struct kmem_cache *s) |
| 453 | { |
| 454 | if (s->flags & SLAB_RED_ZONE) |
| 455 | return s->size - s->red_left_pad; |
| 456 | |
| 457 | return s->size; |
| 458 | } |
| 459 | |
| 460 | static inline void *restore_red_left(struct kmem_cache *s, void *p) |
| 461 | { |
| 462 | if (s->flags & SLAB_RED_ZONE) |
| 463 | p -= s->red_left_pad; |
| 464 | |
| 465 | return p; |
| 466 | } |
| 467 | |
| 468 | /* |
| 469 | * Debug settings: |
| 470 | */ |
| 471 | #if defined(CONFIG_SLUB_DEBUG_ON) |
| 472 | static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS; |
| 473 | #else |
| 474 | static slab_flags_t slub_debug; |
| 475 | #endif |
| 476 | |
| 477 | static char *slub_debug_slabs; |
| 478 | static int disable_higher_order_debug; |
| 479 | |
| 480 | /* |
| 481 | * slub is about to manipulate internal object metadata. This memory lies |
| 482 | * outside the range of the allocated object, so accessing it would normally |
| 483 | * be reported by kasan as a bounds error. metadata_access_enable() is used |
| 484 | * to tell kasan that these accesses are OK. |
| 485 | */ |
| 486 | static inline void metadata_access_enable(void) |
| 487 | { |
| 488 | kasan_disable_current(); |
| 489 | } |
| 490 | |
| 491 | static inline void metadata_access_disable(void) |
| 492 | { |
| 493 | kasan_enable_current(); |
| 494 | } |
| 495 | |
| 496 | /* |
| 497 | * Object debugging |
| 498 | */ |
| 499 | |
| 500 | /* Verify that a pointer has an address that is valid within a slab page */ |
| 501 | static inline int check_valid_pointer(struct kmem_cache *s, |
| 502 | struct page *page, void *object) |
| 503 | { |
| 504 | void *base; |
| 505 | |
| 506 | if (!object) |
| 507 | return 1; |
| 508 | |
| 509 | base = page_address(page); |
| 510 | object = restore_red_left(s, object); |
| 511 | if (object < base || object >= base + page->objects * s->size || |
| 512 | (object - base) % s->size) { |
| 513 | return 0; |
| 514 | } |
| 515 | |
| 516 | return 1; |
| 517 | } |
| 518 | |
| 519 | static void print_section(char *level, char *text, u8 *addr, |
| 520 | unsigned int length) |
| 521 | { |
| 522 | metadata_access_enable(); |
| 523 | print_hex_dump(level, text, DUMP_PREFIX_ADDRESS, 16, 1, addr, |
| 524 | length, 1); |
| 525 | metadata_access_disable(); |
| 526 | } |
| 527 | |
| 528 | static struct track *get_track(struct kmem_cache *s, void *object, |
| 529 | enum track_item alloc) |
| 530 | { |
| 531 | struct track *p; |
| 532 | |
| 533 | if (s->offset) |
| 534 | p = object + s->offset + sizeof(void *); |
| 535 | else |
| 536 | p = object + s->inuse; |
| 537 | |
| 538 | return p + alloc; |
| 539 | } |
| 540 | |
| 541 | static void set_track(struct kmem_cache *s, void *object, |
| 542 | enum track_item alloc, unsigned long addr) |
| 543 | { |
| 544 | struct track *p = get_track(s, object, alloc); |
| 545 | |
| 546 | if (addr) { |
| 547 | #ifdef CONFIG_STACKTRACE |
| 548 | struct stack_trace trace; |
| 549 | int i; |
| 550 | |
| 551 | trace.nr_entries = 0; |
| 552 | trace.max_entries = TRACK_ADDRS_COUNT; |
| 553 | trace.entries = p->addrs; |
| 554 | trace.skip = 3; |
| 555 | metadata_access_enable(); |
| 556 | save_stack_trace(&trace); |
| 557 | metadata_access_disable(); |
| 558 | |
| 559 | /* See rant in lockdep.c */ |
| 560 | if (trace.nr_entries != 0 && |
| 561 | trace.entries[trace.nr_entries - 1] == ULONG_MAX) |
| 562 | trace.nr_entries--; |
| 563 | |
| 564 | for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++) |
| 565 | p->addrs[i] = 0; |
| 566 | #endif |
| 567 | p->addr = addr; |
| 568 | p->cpu = smp_processor_id(); |
| 569 | p->pid = current->pid; |
| 570 | p->when = jiffies; |
| 571 | } else |
| 572 | memset(p, 0, sizeof(struct track)); |
| 573 | } |
| 574 | |
| 575 | static void init_tracking(struct kmem_cache *s, void *object) |
| 576 | { |
| 577 | if (!(s->flags & SLAB_STORE_USER)) |
| 578 | return; |
| 579 | |
| 580 | set_track(s, object, TRACK_FREE, 0UL); |
| 581 | set_track(s, object, TRACK_ALLOC, 0UL); |
| 582 | } |
| 583 | |
| 584 | static void print_track(const char *s, struct track *t, unsigned long pr_time) |
| 585 | { |
| 586 | if (!t->addr) |
| 587 | return; |
| 588 | |
| 589 | pr_err("INFO: %s in %pS age=%lu cpu=%u pid=%d\n", |
| 590 | s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid); |
| 591 | #ifdef CONFIG_STACKTRACE |
| 592 | { |
| 593 | int i; |
| 594 | for (i = 0; i < TRACK_ADDRS_COUNT; i++) |
| 595 | if (t->addrs[i]) |
| 596 | pr_err("\t%pS\n", (void *)t->addrs[i]); |
| 597 | else |
| 598 | break; |
| 599 | } |
| 600 | #endif |
| 601 | } |
| 602 | |
| 603 | static void print_tracking(struct kmem_cache *s, void *object) |
| 604 | { |
| 605 | unsigned long pr_time = jiffies; |
| 606 | if (!(s->flags & SLAB_STORE_USER)) |
| 607 | return; |
| 608 | |
| 609 | print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time); |
| 610 | print_track("Freed", get_track(s, object, TRACK_FREE), pr_time); |
| 611 | } |
| 612 | |
| 613 | static void print_page_info(struct page *page) |
| 614 | { |
| 615 | pr_err("INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n", |
| 616 | page, page->objects, page->inuse, page->freelist, page->flags); |
| 617 | |
| 618 | } |
| 619 | |
| 620 | static void slab_bug(struct kmem_cache *s, char *fmt, ...) |
| 621 | { |
| 622 | struct va_format vaf; |
| 623 | va_list args; |
| 624 | |
| 625 | va_start(args, fmt); |
| 626 | vaf.fmt = fmt; |
| 627 | vaf.va = &args; |
| 628 | pr_err("=============================================================================\n"); |
| 629 | pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf); |
| 630 | pr_err("-----------------------------------------------------------------------------\n\n"); |
| 631 | |
| 632 | add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); |
| 633 | va_end(args); |
| 634 | } |
| 635 | |
| 636 | static void slab_fix(struct kmem_cache *s, char *fmt, ...) |
| 637 | { |
| 638 | struct va_format vaf; |
| 639 | va_list args; |
| 640 | |
| 641 | va_start(args, fmt); |
| 642 | vaf.fmt = fmt; |
| 643 | vaf.va = &args; |
| 644 | pr_err("FIX %s: %pV\n", s->name, &vaf); |
| 645 | va_end(args); |
| 646 | } |
| 647 | |
| 648 | static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p) |
| 649 | { |
| 650 | unsigned int off; /* Offset of last byte */ |
| 651 | u8 *addr = page_address(page); |
| 652 | |
| 653 | print_tracking(s, p); |
| 654 | |
| 655 | print_page_info(page); |
| 656 | |
| 657 | pr_err("INFO: Object 0x%p @offset=%tu fp=0x%p\n\n", |
| 658 | p, p - addr, get_freepointer(s, p)); |
| 659 | |
| 660 | if (s->flags & SLAB_RED_ZONE) |
| 661 | print_section(KERN_ERR, "Redzone ", p - s->red_left_pad, |
| 662 | s->red_left_pad); |
| 663 | else if (p > addr + 16) |
| 664 | print_section(KERN_ERR, "Bytes b4 ", p - 16, 16); |
| 665 | |
| 666 | print_section(KERN_ERR, "Object ", p, |
| 667 | min_t(unsigned int, s->object_size, PAGE_SIZE)); |
| 668 | if (s->flags & SLAB_RED_ZONE) |
| 669 | print_section(KERN_ERR, "Redzone ", p + s->object_size, |
| 670 | s->inuse - s->object_size); |
| 671 | |
| 672 | if (s->offset) |
| 673 | off = s->offset + sizeof(void *); |
| 674 | else |
| 675 | off = s->inuse; |
| 676 | |
| 677 | if (s->flags & SLAB_STORE_USER) |
| 678 | off += 2 * sizeof(struct track); |
| 679 | |
| 680 | off += kasan_metadata_size(s); |
| 681 | |
| 682 | if (off != size_from_object(s)) |
| 683 | /* Beginning of the filler is the free pointer */ |
| 684 | print_section(KERN_ERR, "Padding ", p + off, |
| 685 | size_from_object(s) - off); |
| 686 | |
| 687 | dump_stack(); |
| 688 | } |
| 689 | |
| 690 | void object_err(struct kmem_cache *s, struct page *page, |
| 691 | u8 *object, char *reason) |
| 692 | { |
| 693 | slab_bug(s, "%s", reason); |
| 694 | print_trailer(s, page, object); |
| 695 | } |
| 696 | |
| 697 | static __printf(3, 4) void slab_err(struct kmem_cache *s, struct page *page, |
| 698 | const char *fmt, ...) |
| 699 | { |
| 700 | va_list args; |
| 701 | char buf[100]; |
| 702 | |
| 703 | va_start(args, fmt); |
| 704 | vsnprintf(buf, sizeof(buf), fmt, args); |
| 705 | va_end(args); |
| 706 | slab_bug(s, "%s", buf); |
| 707 | print_page_info(page); |
| 708 | dump_stack(); |
| 709 | } |
| 710 | |
| 711 | static void init_object(struct kmem_cache *s, void *object, u8 val) |
| 712 | { |
| 713 | u8 *p = object; |
| 714 | |
| 715 | if (s->flags & SLAB_RED_ZONE) |
| 716 | memset(p - s->red_left_pad, val, s->red_left_pad); |
| 717 | |
| 718 | if (s->flags & __OBJECT_POISON) { |
| 719 | memset(p, POISON_FREE, s->object_size - 1); |
| 720 | p[s->object_size - 1] = POISON_END; |
| 721 | } |
| 722 | |
| 723 | if (s->flags & SLAB_RED_ZONE) |
| 724 | memset(p + s->object_size, val, s->inuse - s->object_size); |
| 725 | } |
| 726 | |
| 727 | static void restore_bytes(struct kmem_cache *s, char *message, u8 data, |
| 728 | void *from, void *to) |
| 729 | { |
| 730 | slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data); |
| 731 | memset(from, data, to - from); |
| 732 | } |
| 733 | |
| 734 | static int check_bytes_and_report(struct kmem_cache *s, struct page *page, |
| 735 | u8 *object, char *what, |
| 736 | u8 *start, unsigned int value, unsigned int bytes) |
| 737 | { |
| 738 | u8 *fault; |
| 739 | u8 *end; |
| 740 | |
| 741 | metadata_access_enable(); |
| 742 | fault = memchr_inv(start, value, bytes); |
| 743 | metadata_access_disable(); |
| 744 | if (!fault) |
| 745 | return 1; |
| 746 | |
| 747 | end = start + bytes; |
| 748 | while (end > fault && end[-1] == value) |
| 749 | end--; |
| 750 | |
| 751 | slab_bug(s, "%s overwritten", what); |
| 752 | pr_err("INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n", |
| 753 | fault, end - 1, fault[0], value); |
| 754 | print_trailer(s, page, object); |
| 755 | |
| 756 | restore_bytes(s, what, value, fault, end); |
| 757 | return 0; |
| 758 | } |
| 759 | |
| 760 | /* |
| 761 | * Object layout: |
| 762 | * |
| 763 | * object address |
| 764 | * Bytes of the object to be managed. |
| 765 | * If the freepointer may overlay the object then the free |
| 766 | * pointer is the first word of the object. |
| 767 | * |
| 768 | * Poisoning uses 0x6b (POISON_FREE) and the last byte is |
| 769 | * 0xa5 (POISON_END) |
| 770 | * |
| 771 | * object + s->object_size |
| 772 | * Padding to reach word boundary. This is also used for Redzoning. |
| 773 | * Padding is extended by another word if Redzoning is enabled and |
| 774 | * object_size == inuse. |
| 775 | * |
| 776 | * We fill with 0xbb (RED_INACTIVE) for inactive objects and with |
| 777 | * 0xcc (RED_ACTIVE) for objects in use. |
| 778 | * |
| 779 | * object + s->inuse |
| 780 | * Meta data starts here. |
| 781 | * |
| 782 | * A. Free pointer (if we cannot overwrite object on free) |
| 783 | * B. Tracking data for SLAB_STORE_USER |
| 784 | * C. Padding to reach required alignment boundary or at mininum |
| 785 | * one word if debugging is on to be able to detect writes |
| 786 | * before the word boundary. |
| 787 | * |
| 788 | * Padding is done using 0x5a (POISON_INUSE) |
| 789 | * |
| 790 | * object + s->size |
| 791 | * Nothing is used beyond s->size. |
| 792 | * |
| 793 | * If slabcaches are merged then the object_size and inuse boundaries are mostly |
| 794 | * ignored. And therefore no slab options that rely on these boundaries |
| 795 | * may be used with merged slabcaches. |
| 796 | */ |
| 797 | |
| 798 | static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p) |
| 799 | { |
| 800 | unsigned long off = s->inuse; /* The end of info */ |
| 801 | |
| 802 | if (s->offset) |
| 803 | /* Freepointer is placed after the object. */ |
| 804 | off += sizeof(void *); |
| 805 | |
| 806 | if (s->flags & SLAB_STORE_USER) |
| 807 | /* We also have user information there */ |
| 808 | off += 2 * sizeof(struct track); |
| 809 | |
| 810 | off += kasan_metadata_size(s); |
| 811 | |
| 812 | if (size_from_object(s) == off) |
| 813 | return 1; |
| 814 | |
| 815 | return check_bytes_and_report(s, page, p, "Object padding", |
| 816 | p + off, POISON_INUSE, size_from_object(s) - off); |
| 817 | } |
| 818 | |
| 819 | /* Check the pad bytes at the end of a slab page */ |
| 820 | static int slab_pad_check(struct kmem_cache *s, struct page *page) |
| 821 | { |
| 822 | u8 *start; |
| 823 | u8 *fault; |
| 824 | u8 *end; |
| 825 | u8 *pad; |
| 826 | int length; |
| 827 | int remainder; |
| 828 | |
| 829 | if (!(s->flags & SLAB_POISON)) |
| 830 | return 1; |
| 831 | |
| 832 | start = page_address(page); |
| 833 | length = PAGE_SIZE << compound_order(page); |
| 834 | end = start + length; |
| 835 | remainder = length % s->size; |
| 836 | if (!remainder) |
| 837 | return 1; |
| 838 | |
| 839 | pad = end - remainder; |
| 840 | metadata_access_enable(); |
| 841 | fault = memchr_inv(pad, POISON_INUSE, remainder); |
| 842 | metadata_access_disable(); |
| 843 | if (!fault) |
| 844 | return 1; |
| 845 | while (end > fault && end[-1] == POISON_INUSE) |
| 846 | end--; |
| 847 | |
| 848 | slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1); |
| 849 | print_section(KERN_ERR, "Padding ", pad, remainder); |
| 850 | |
| 851 | restore_bytes(s, "slab padding", POISON_INUSE, fault, end); |
| 852 | return 0; |
| 853 | } |
| 854 | |
| 855 | static int check_object(struct kmem_cache *s, struct page *page, |
| 856 | void *object, u8 val) |
| 857 | { |
| 858 | u8 *p = object; |
| 859 | u8 *endobject = object + s->object_size; |
| 860 | |
| 861 | if (s->flags & SLAB_RED_ZONE) { |
| 862 | if (!check_bytes_and_report(s, page, object, "Redzone", |
| 863 | object - s->red_left_pad, val, s->red_left_pad)) |
| 864 | return 0; |
| 865 | |
| 866 | if (!check_bytes_and_report(s, page, object, "Redzone", |
| 867 | endobject, val, s->inuse - s->object_size)) |
| 868 | return 0; |
| 869 | } else { |
| 870 | if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) { |
| 871 | check_bytes_and_report(s, page, p, "Alignment padding", |
| 872 | endobject, POISON_INUSE, |
| 873 | s->inuse - s->object_size); |
| 874 | } |
| 875 | } |
| 876 | |
| 877 | if (s->flags & SLAB_POISON) { |
| 878 | if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) && |
| 879 | (!check_bytes_and_report(s, page, p, "Poison", p, |
| 880 | POISON_FREE, s->object_size - 1) || |
| 881 | !check_bytes_and_report(s, page, p, "Poison", |
| 882 | p + s->object_size - 1, POISON_END, 1))) |
| 883 | return 0; |
| 884 | /* |
| 885 | * check_pad_bytes cleans up on its own. |
| 886 | */ |
| 887 | check_pad_bytes(s, page, p); |
| 888 | } |
| 889 | |
| 890 | if (!s->offset && val == SLUB_RED_ACTIVE) |
| 891 | /* |
| 892 | * Object and freepointer overlap. Cannot check |
| 893 | * freepointer while object is allocated. |
| 894 | */ |
| 895 | return 1; |
| 896 | |
| 897 | /* Check free pointer validity */ |
| 898 | if (!check_valid_pointer(s, page, get_freepointer(s, p))) { |
| 899 | object_err(s, page, p, "Freepointer corrupt"); |
| 900 | /* |
| 901 | * No choice but to zap it and thus lose the remainder |
| 902 | * of the free objects in this slab. May cause |
| 903 | * another error because the object count is now wrong. |
| 904 | */ |
| 905 | set_freepointer(s, p, NULL); |
| 906 | return 0; |
| 907 | } |
| 908 | return 1; |
| 909 | } |
| 910 | |
| 911 | static int check_slab(struct kmem_cache *s, struct page *page) |
| 912 | { |
| 913 | int maxobj; |
| 914 | |
| 915 | VM_BUG_ON(!irqs_disabled()); |
| 916 | |
| 917 | if (!PageSlab(page)) { |
| 918 | slab_err(s, page, "Not a valid slab page"); |
| 919 | return 0; |
| 920 | } |
| 921 | |
| 922 | maxobj = order_objects(compound_order(page), s->size); |
| 923 | if (page->objects > maxobj) { |
| 924 | slab_err(s, page, "objects %u > max %u", |
| 925 | page->objects, maxobj); |
| 926 | return 0; |
| 927 | } |
| 928 | if (page->inuse > page->objects) { |
| 929 | slab_err(s, page, "inuse %u > max %u", |
| 930 | page->inuse, page->objects); |
| 931 | return 0; |
| 932 | } |
| 933 | /* Slab_pad_check fixes things up after itself */ |
| 934 | slab_pad_check(s, page); |
| 935 | return 1; |
| 936 | } |
| 937 | |
| 938 | /* |
| 939 | * Determine if a certain object on a page is on the freelist. Must hold the |
| 940 | * slab lock to guarantee that the chains are in a consistent state. |
| 941 | */ |
| 942 | static int on_freelist(struct kmem_cache *s, struct page *page, void *search) |
| 943 | { |
| 944 | int nr = 0; |
| 945 | void *fp; |
| 946 | void *object = NULL; |
| 947 | int max_objects; |
| 948 | |
| 949 | fp = page->freelist; |
| 950 | while (fp && nr <= page->objects) { |
| 951 | if (fp == search) |
| 952 | return 1; |
| 953 | if (!check_valid_pointer(s, page, fp)) { |
| 954 | if (object) { |
| 955 | object_err(s, page, object, |
| 956 | "Freechain corrupt"); |
| 957 | set_freepointer(s, object, NULL); |
| 958 | } else { |
| 959 | slab_err(s, page, "Freepointer corrupt"); |
| 960 | page->freelist = NULL; |
| 961 | page->inuse = page->objects; |
| 962 | slab_fix(s, "Freelist cleared"); |
| 963 | return 0; |
| 964 | } |
| 965 | break; |
| 966 | } |
| 967 | object = fp; |
| 968 | fp = get_freepointer(s, object); |
| 969 | nr++; |
| 970 | } |
| 971 | |
| 972 | max_objects = order_objects(compound_order(page), s->size); |
| 973 | if (max_objects > MAX_OBJS_PER_PAGE) |
| 974 | max_objects = MAX_OBJS_PER_PAGE; |
| 975 | |
| 976 | if (page->objects != max_objects) { |
| 977 | slab_err(s, page, "Wrong number of objects. Found %d but should be %d", |
| 978 | page->objects, max_objects); |
| 979 | page->objects = max_objects; |
| 980 | slab_fix(s, "Number of objects adjusted."); |
| 981 | } |
| 982 | if (page->inuse != page->objects - nr) { |
| 983 | slab_err(s, page, "Wrong object count. Counter is %d but counted were %d", |
| 984 | page->inuse, page->objects - nr); |
| 985 | page->inuse = page->objects - nr; |
| 986 | slab_fix(s, "Object count adjusted."); |
| 987 | } |
| 988 | return search == NULL; |
| 989 | } |
| 990 | |
| 991 | static void trace(struct kmem_cache *s, struct page *page, void *object, |
| 992 | int alloc) |
| 993 | { |
| 994 | if (s->flags & SLAB_TRACE) { |
| 995 | pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n", |
| 996 | s->name, |
| 997 | alloc ? "alloc" : "free", |
| 998 | object, page->inuse, |
| 999 | page->freelist); |
| 1000 | |
| 1001 | if (!alloc) |
| 1002 | print_section(KERN_INFO, "Object ", (void *)object, |
| 1003 | s->object_size); |
| 1004 | |
| 1005 | dump_stack(); |
| 1006 | } |
| 1007 | } |
| 1008 | |
| 1009 | /* |
| 1010 | * Tracking of fully allocated slabs for debugging purposes. |
| 1011 | */ |
| 1012 | static void add_full(struct kmem_cache *s, |
| 1013 | struct kmem_cache_node *n, struct page *page) |
| 1014 | { |
| 1015 | if (!(s->flags & SLAB_STORE_USER)) |
| 1016 | return; |
| 1017 | |
| 1018 | lockdep_assert_held(&n->list_lock); |
| 1019 | list_add(&page->lru, &n->full); |
| 1020 | } |
| 1021 | |
| 1022 | static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct page *page) |
| 1023 | { |
| 1024 | if (!(s->flags & SLAB_STORE_USER)) |
| 1025 | return; |
| 1026 | |
| 1027 | lockdep_assert_held(&n->list_lock); |
| 1028 | list_del(&page->lru); |
| 1029 | } |
| 1030 | |
| 1031 | /* Tracking of the number of slabs for debugging purposes */ |
| 1032 | static inline unsigned long slabs_node(struct kmem_cache *s, int node) |
| 1033 | { |
| 1034 | struct kmem_cache_node *n = get_node(s, node); |
| 1035 | |
| 1036 | return atomic_long_read(&n->nr_slabs); |
| 1037 | } |
| 1038 | |
| 1039 | static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) |
| 1040 | { |
| 1041 | return atomic_long_read(&n->nr_slabs); |
| 1042 | } |
| 1043 | |
| 1044 | static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects) |
| 1045 | { |
| 1046 | struct kmem_cache_node *n = get_node(s, node); |
| 1047 | |
| 1048 | /* |
| 1049 | * May be called early in order to allocate a slab for the |
| 1050 | * kmem_cache_node structure. Solve the chicken-egg |
| 1051 | * dilemma by deferring the increment of the count during |
| 1052 | * bootstrap (see early_kmem_cache_node_alloc). |
| 1053 | */ |
| 1054 | if (likely(n)) { |
| 1055 | atomic_long_inc(&n->nr_slabs); |
| 1056 | atomic_long_add(objects, &n->total_objects); |
| 1057 | } |
| 1058 | } |
| 1059 | static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects) |
| 1060 | { |
| 1061 | struct kmem_cache_node *n = get_node(s, node); |
| 1062 | |
| 1063 | atomic_long_dec(&n->nr_slabs); |
| 1064 | atomic_long_sub(objects, &n->total_objects); |
| 1065 | } |
| 1066 | |
| 1067 | /* Object debug checks for alloc/free paths */ |
| 1068 | static void setup_object_debug(struct kmem_cache *s, struct page *page, |
| 1069 | void *object) |
| 1070 | { |
| 1071 | if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))) |
| 1072 | return; |
| 1073 | |
| 1074 | init_object(s, object, SLUB_RED_INACTIVE); |
| 1075 | init_tracking(s, object); |
| 1076 | } |
| 1077 | |
| 1078 | static inline int alloc_consistency_checks(struct kmem_cache *s, |
| 1079 | struct page *page, |
| 1080 | void *object, unsigned long addr) |
| 1081 | { |
| 1082 | if (!check_slab(s, page)) |
| 1083 | return 0; |
| 1084 | |
| 1085 | if (!check_valid_pointer(s, page, object)) { |
| 1086 | object_err(s, page, object, "Freelist Pointer check fails"); |
| 1087 | return 0; |
| 1088 | } |
| 1089 | |
| 1090 | if (!check_object(s, page, object, SLUB_RED_INACTIVE)) |
| 1091 | return 0; |
| 1092 | |
| 1093 | return 1; |
| 1094 | } |
| 1095 | |
| 1096 | static noinline int alloc_debug_processing(struct kmem_cache *s, |
| 1097 | struct page *page, |
| 1098 | void *object, unsigned long addr) |
| 1099 | { |
| 1100 | if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
| 1101 | if (!alloc_consistency_checks(s, page, object, addr)) |
| 1102 | goto bad; |
| 1103 | } |
| 1104 | |
| 1105 | /* Success perform special debug activities for allocs */ |
| 1106 | if (s->flags & SLAB_STORE_USER) |
| 1107 | set_track(s, object, TRACK_ALLOC, addr); |
| 1108 | trace(s, page, object, 1); |
| 1109 | init_object(s, object, SLUB_RED_ACTIVE); |
| 1110 | return 1; |
| 1111 | |
| 1112 | bad: |
| 1113 | if (PageSlab(page)) { |
| 1114 | /* |
| 1115 | * If this is a slab page then lets do the best we can |
| 1116 | * to avoid issues in the future. Marking all objects |
| 1117 | * as used avoids touching the remaining objects. |
| 1118 | */ |
| 1119 | slab_fix(s, "Marking all objects used"); |
| 1120 | page->inuse = page->objects; |
| 1121 | page->freelist = NULL; |
| 1122 | } |
| 1123 | return 0; |
| 1124 | } |
| 1125 | |
| 1126 | static inline int free_consistency_checks(struct kmem_cache *s, |
| 1127 | struct page *page, void *object, unsigned long addr) |
| 1128 | { |
| 1129 | if (!check_valid_pointer(s, page, object)) { |
| 1130 | slab_err(s, page, "Invalid object pointer 0x%p", object); |
| 1131 | return 0; |
| 1132 | } |
| 1133 | |
| 1134 | if (on_freelist(s, page, object)) { |
| 1135 | object_err(s, page, object, "Object already free"); |
| 1136 | return 0; |
| 1137 | } |
| 1138 | |
| 1139 | if (!check_object(s, page, object, SLUB_RED_ACTIVE)) |
| 1140 | return 0; |
| 1141 | |
| 1142 | if (unlikely(s != page->slab_cache)) { |
| 1143 | if (!PageSlab(page)) { |
| 1144 | slab_err(s, page, "Attempt to free object(0x%p) outside of slab", |
| 1145 | object); |
| 1146 | } else if (!page->slab_cache) { |
| 1147 | pr_err("SLUB <none>: no slab for object 0x%p.\n", |
| 1148 | object); |
| 1149 | dump_stack(); |
| 1150 | } else |
| 1151 | object_err(s, page, object, |
| 1152 | "page slab pointer corrupt."); |
| 1153 | return 0; |
| 1154 | } |
| 1155 | return 1; |
| 1156 | } |
| 1157 | |
| 1158 | /* Supports checking bulk free of a constructed freelist */ |
| 1159 | static noinline int free_debug_processing( |
| 1160 | struct kmem_cache *s, struct page *page, |
| 1161 | void *head, void *tail, int bulk_cnt, |
| 1162 | unsigned long addr) |
| 1163 | { |
| 1164 | struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
| 1165 | void *object = head; |
| 1166 | int cnt = 0; |
| 1167 | unsigned long uninitialized_var(flags); |
| 1168 | int ret = 0; |
| 1169 | |
| 1170 | spin_lock_irqsave(&n->list_lock, flags); |
| 1171 | slab_lock(page); |
| 1172 | |
| 1173 | if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
| 1174 | if (!check_slab(s, page)) |
| 1175 | goto out; |
| 1176 | } |
| 1177 | |
| 1178 | next_object: |
| 1179 | cnt++; |
| 1180 | |
| 1181 | if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
| 1182 | if (!free_consistency_checks(s, page, object, addr)) |
| 1183 | goto out; |
| 1184 | } |
| 1185 | |
| 1186 | if (s->flags & SLAB_STORE_USER) |
| 1187 | set_track(s, object, TRACK_FREE, addr); |
| 1188 | trace(s, page, object, 0); |
| 1189 | /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */ |
| 1190 | init_object(s, object, SLUB_RED_INACTIVE); |
| 1191 | |
| 1192 | /* Reached end of constructed freelist yet? */ |
| 1193 | if (object != tail) { |
| 1194 | object = get_freepointer(s, object); |
| 1195 | goto next_object; |
| 1196 | } |
| 1197 | ret = 1; |
| 1198 | |
| 1199 | out: |
| 1200 | if (cnt != bulk_cnt) |
| 1201 | slab_err(s, page, "Bulk freelist count(%d) invalid(%d)\n", |
| 1202 | bulk_cnt, cnt); |
| 1203 | |
| 1204 | slab_unlock(page); |
| 1205 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 1206 | if (!ret) |
| 1207 | slab_fix(s, "Object at 0x%p not freed", object); |
| 1208 | return ret; |
| 1209 | } |
| 1210 | |
| 1211 | static int __init setup_slub_debug(char *str) |
| 1212 | { |
| 1213 | slub_debug = DEBUG_DEFAULT_FLAGS; |
| 1214 | if (*str++ != '=' || !*str) |
| 1215 | /* |
| 1216 | * No options specified. Switch on full debugging. |
| 1217 | */ |
| 1218 | goto out; |
| 1219 | |
| 1220 | if (*str == ',') |
| 1221 | /* |
| 1222 | * No options but restriction on slabs. This means full |
| 1223 | * debugging for slabs matching a pattern. |
| 1224 | */ |
| 1225 | goto check_slabs; |
| 1226 | |
| 1227 | slub_debug = 0; |
| 1228 | if (*str == '-') |
| 1229 | /* |
| 1230 | * Switch off all debugging measures. |
| 1231 | */ |
| 1232 | goto out; |
| 1233 | |
| 1234 | /* |
| 1235 | * Determine which debug features should be switched on |
| 1236 | */ |
| 1237 | for (; *str && *str != ','; str++) { |
| 1238 | switch (tolower(*str)) { |
| 1239 | case 'f': |
| 1240 | slub_debug |= SLAB_CONSISTENCY_CHECKS; |
| 1241 | break; |
| 1242 | case 'z': |
| 1243 | slub_debug |= SLAB_RED_ZONE; |
| 1244 | break; |
| 1245 | case 'p': |
| 1246 | slub_debug |= SLAB_POISON; |
| 1247 | break; |
| 1248 | case 'u': |
| 1249 | slub_debug |= SLAB_STORE_USER; |
| 1250 | break; |
| 1251 | case 't': |
| 1252 | slub_debug |= SLAB_TRACE; |
| 1253 | break; |
| 1254 | case 'a': |
| 1255 | slub_debug |= SLAB_FAILSLAB; |
| 1256 | break; |
| 1257 | case 'o': |
| 1258 | /* |
| 1259 | * Avoid enabling debugging on caches if its minimum |
| 1260 | * order would increase as a result. |
| 1261 | */ |
| 1262 | disable_higher_order_debug = 1; |
| 1263 | break; |
| 1264 | default: |
| 1265 | pr_err("slub_debug option '%c' unknown. skipped\n", |
| 1266 | *str); |
| 1267 | } |
| 1268 | } |
| 1269 | |
| 1270 | check_slabs: |
| 1271 | if (*str == ',') |
| 1272 | slub_debug_slabs = str + 1; |
| 1273 | out: |
| 1274 | return 1; |
| 1275 | } |
| 1276 | |
| 1277 | __setup("slub_debug", setup_slub_debug); |
| 1278 | |
| 1279 | /* |
| 1280 | * kmem_cache_flags - apply debugging options to the cache |
| 1281 | * @object_size: the size of an object without meta data |
| 1282 | * @flags: flags to set |
| 1283 | * @name: name of the cache |
| 1284 | * @ctor: constructor function |
| 1285 | * |
| 1286 | * Debug option(s) are applied to @flags. In addition to the debug |
| 1287 | * option(s), if a slab name (or multiple) is specified i.e. |
| 1288 | * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ... |
| 1289 | * then only the select slabs will receive the debug option(s). |
| 1290 | */ |
| 1291 | slab_flags_t kmem_cache_flags(unsigned int object_size, |
| 1292 | slab_flags_t flags, const char *name, |
| 1293 | void (*ctor)(void *)) |
| 1294 | { |
| 1295 | char *iter; |
| 1296 | size_t len; |
| 1297 | |
| 1298 | /* If slub_debug = 0, it folds into the if conditional. */ |
| 1299 | if (!slub_debug_slabs) |
| 1300 | return flags | slub_debug; |
| 1301 | |
| 1302 | len = strlen(name); |
| 1303 | iter = slub_debug_slabs; |
| 1304 | while (*iter) { |
| 1305 | char *end, *glob; |
| 1306 | size_t cmplen; |
| 1307 | |
| 1308 | end = strchr(iter, ','); |
| 1309 | if (!end) |
| 1310 | end = iter + strlen(iter); |
| 1311 | |
| 1312 | glob = strnchr(iter, end - iter, '*'); |
| 1313 | if (glob) |
| 1314 | cmplen = glob - iter; |
| 1315 | else |
| 1316 | cmplen = max_t(size_t, len, (end - iter)); |
| 1317 | |
| 1318 | if (!strncmp(name, iter, cmplen)) { |
| 1319 | flags |= slub_debug; |
| 1320 | break; |
| 1321 | } |
| 1322 | |
| 1323 | if (!*end) |
| 1324 | break; |
| 1325 | iter = end + 1; |
| 1326 | } |
| 1327 | |
| 1328 | return flags; |
| 1329 | } |
| 1330 | #else /* !CONFIG_SLUB_DEBUG */ |
| 1331 | static inline void setup_object_debug(struct kmem_cache *s, |
| 1332 | struct page *page, void *object) {} |
| 1333 | |
| 1334 | static inline int alloc_debug_processing(struct kmem_cache *s, |
| 1335 | struct page *page, void *object, unsigned long addr) { return 0; } |
| 1336 | |
| 1337 | static inline int free_debug_processing( |
| 1338 | struct kmem_cache *s, struct page *page, |
| 1339 | void *head, void *tail, int bulk_cnt, |
| 1340 | unsigned long addr) { return 0; } |
| 1341 | |
| 1342 | static inline int slab_pad_check(struct kmem_cache *s, struct page *page) |
| 1343 | { return 1; } |
| 1344 | static inline int check_object(struct kmem_cache *s, struct page *page, |
| 1345 | void *object, u8 val) { return 1; } |
| 1346 | static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n, |
| 1347 | struct page *page) {} |
| 1348 | static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, |
| 1349 | struct page *page) {} |
| 1350 | slab_flags_t kmem_cache_flags(unsigned int object_size, |
| 1351 | slab_flags_t flags, const char *name, |
| 1352 | void (*ctor)(void *)) |
| 1353 | { |
| 1354 | return flags; |
| 1355 | } |
| 1356 | #define slub_debug 0 |
| 1357 | |
| 1358 | #define disable_higher_order_debug 0 |
| 1359 | |
| 1360 | static inline unsigned long slabs_node(struct kmem_cache *s, int node) |
| 1361 | { return 0; } |
| 1362 | static inline unsigned long node_nr_slabs(struct kmem_cache_node *n) |
| 1363 | { return 0; } |
| 1364 | static inline void inc_slabs_node(struct kmem_cache *s, int node, |
| 1365 | int objects) {} |
| 1366 | static inline void dec_slabs_node(struct kmem_cache *s, int node, |
| 1367 | int objects) {} |
| 1368 | |
| 1369 | #endif /* CONFIG_SLUB_DEBUG */ |
| 1370 | |
| 1371 | /* |
| 1372 | * Hooks for other subsystems that check memory allocations. In a typical |
| 1373 | * production configuration these hooks all should produce no code at all. |
| 1374 | */ |
| 1375 | static inline void *kmalloc_large_node_hook(void *ptr, size_t size, gfp_t flags) |
| 1376 | { |
| 1377 | kmemleak_alloc(ptr, size, 1, flags); |
| 1378 | return kasan_kmalloc_large(ptr, size, flags); |
| 1379 | } |
| 1380 | |
| 1381 | static __always_inline void kfree_hook(void *x) |
| 1382 | { |
| 1383 | kmemleak_free(x); |
| 1384 | kasan_kfree_large(x, _RET_IP_); |
| 1385 | } |
| 1386 | |
| 1387 | static __always_inline bool slab_free_hook(struct kmem_cache *s, void *x) |
| 1388 | { |
| 1389 | kmemleak_free_recursive(x, s->flags); |
| 1390 | |
| 1391 | /* |
| 1392 | * Trouble is that we may no longer disable interrupts in the fast path |
| 1393 | * So in order to make the debug calls that expect irqs to be |
| 1394 | * disabled we need to disable interrupts temporarily. |
| 1395 | */ |
| 1396 | #ifdef CONFIG_LOCKDEP |
| 1397 | { |
| 1398 | unsigned long flags; |
| 1399 | |
| 1400 | local_irq_save(flags); |
| 1401 | debug_check_no_locks_freed(x, s->object_size); |
| 1402 | local_irq_restore(flags); |
| 1403 | } |
| 1404 | #endif |
| 1405 | if (!(s->flags & SLAB_DEBUG_OBJECTS)) |
| 1406 | debug_check_no_obj_freed(x, s->object_size); |
| 1407 | |
| 1408 | /* KASAN might put x into memory quarantine, delaying its reuse */ |
| 1409 | return kasan_slab_free(s, x, _RET_IP_); |
| 1410 | } |
| 1411 | |
| 1412 | static inline bool slab_free_freelist_hook(struct kmem_cache *s, |
| 1413 | void **head, void **tail) |
| 1414 | { |
| 1415 | /* |
| 1416 | * Compiler cannot detect this function can be removed if slab_free_hook() |
| 1417 | * evaluates to nothing. Thus, catch all relevant config debug options here. |
| 1418 | */ |
| 1419 | #if defined(CONFIG_LOCKDEP) || \ |
| 1420 | defined(CONFIG_DEBUG_KMEMLEAK) || \ |
| 1421 | defined(CONFIG_DEBUG_OBJECTS_FREE) || \ |
| 1422 | defined(CONFIG_KASAN) |
| 1423 | |
| 1424 | void *object; |
| 1425 | void *next = *head; |
| 1426 | void *old_tail = *tail ? *tail : *head; |
| 1427 | |
| 1428 | /* Head and tail of the reconstructed freelist */ |
| 1429 | *head = NULL; |
| 1430 | *tail = NULL; |
| 1431 | |
| 1432 | do { |
| 1433 | object = next; |
| 1434 | next = get_freepointer(s, object); |
| 1435 | /* If object's reuse doesn't have to be delayed */ |
| 1436 | if (!slab_free_hook(s, object)) { |
| 1437 | /* Move object to the new freelist */ |
| 1438 | set_freepointer(s, object, *head); |
| 1439 | *head = object; |
| 1440 | if (!*tail) |
| 1441 | *tail = object; |
| 1442 | } |
| 1443 | } while (object != old_tail); |
| 1444 | |
| 1445 | if (*head == *tail) |
| 1446 | *tail = NULL; |
| 1447 | |
| 1448 | return *head != NULL; |
| 1449 | #else |
| 1450 | return true; |
| 1451 | #endif |
| 1452 | } |
| 1453 | |
| 1454 | static void *setup_object(struct kmem_cache *s, struct page *page, |
| 1455 | void *object) |
| 1456 | { |
| 1457 | setup_object_debug(s, page, object); |
| 1458 | object = kasan_init_slab_obj(s, object); |
| 1459 | if (unlikely(s->ctor)) { |
| 1460 | kasan_unpoison_object_data(s, object); |
| 1461 | s->ctor(object); |
| 1462 | kasan_poison_object_data(s, object); |
| 1463 | } |
| 1464 | return object; |
| 1465 | } |
| 1466 | |
| 1467 | /* |
| 1468 | * Slab allocation and freeing |
| 1469 | */ |
| 1470 | static inline struct page *alloc_slab_page(struct kmem_cache *s, |
| 1471 | gfp_t flags, int node, struct kmem_cache_order_objects oo) |
| 1472 | { |
| 1473 | struct page *page; |
| 1474 | unsigned int order = oo_order(oo); |
| 1475 | |
| 1476 | if (node == NUMA_NO_NODE) |
| 1477 | page = alloc_pages(flags, order); |
| 1478 | else |
| 1479 | page = __alloc_pages_node(node, flags, order); |
| 1480 | |
| 1481 | if (page && memcg_charge_slab(page, flags, order, s)) { |
| 1482 | __free_pages(page, order); |
| 1483 | page = NULL; |
| 1484 | } |
| 1485 | |
| 1486 | return page; |
| 1487 | } |
| 1488 | |
| 1489 | #ifdef CONFIG_SLAB_FREELIST_RANDOM |
| 1490 | /* Pre-initialize the random sequence cache */ |
| 1491 | static int init_cache_random_seq(struct kmem_cache *s) |
| 1492 | { |
| 1493 | unsigned int count = oo_objects(s->oo); |
| 1494 | int err; |
| 1495 | |
| 1496 | /* Bailout if already initialised */ |
| 1497 | if (s->random_seq) |
| 1498 | return 0; |
| 1499 | |
| 1500 | err = cache_random_seq_create(s, count, GFP_KERNEL); |
| 1501 | if (err) { |
| 1502 | pr_err("SLUB: Unable to initialize free list for %s\n", |
| 1503 | s->name); |
| 1504 | return err; |
| 1505 | } |
| 1506 | |
| 1507 | /* Transform to an offset on the set of pages */ |
| 1508 | if (s->random_seq) { |
| 1509 | unsigned int i; |
| 1510 | |
| 1511 | for (i = 0; i < count; i++) |
| 1512 | s->random_seq[i] *= s->size; |
| 1513 | } |
| 1514 | return 0; |
| 1515 | } |
| 1516 | |
| 1517 | /* Initialize each random sequence freelist per cache */ |
| 1518 | static void __init init_freelist_randomization(void) |
| 1519 | { |
| 1520 | struct kmem_cache *s; |
| 1521 | |
| 1522 | mutex_lock(&slab_mutex); |
| 1523 | |
| 1524 | list_for_each_entry(s, &slab_caches, list) |
| 1525 | init_cache_random_seq(s); |
| 1526 | |
| 1527 | mutex_unlock(&slab_mutex); |
| 1528 | } |
| 1529 | |
| 1530 | /* Get the next entry on the pre-computed freelist randomized */ |
| 1531 | static void *next_freelist_entry(struct kmem_cache *s, struct page *page, |
| 1532 | unsigned long *pos, void *start, |
| 1533 | unsigned long page_limit, |
| 1534 | unsigned long freelist_count) |
| 1535 | { |
| 1536 | unsigned int idx; |
| 1537 | |
| 1538 | /* |
| 1539 | * If the target page allocation failed, the number of objects on the |
| 1540 | * page might be smaller than the usual size defined by the cache. |
| 1541 | */ |
| 1542 | do { |
| 1543 | idx = s->random_seq[*pos]; |
| 1544 | *pos += 1; |
| 1545 | if (*pos >= freelist_count) |
| 1546 | *pos = 0; |
| 1547 | } while (unlikely(idx >= page_limit)); |
| 1548 | |
| 1549 | return (char *)start + idx; |
| 1550 | } |
| 1551 | |
| 1552 | /* Shuffle the single linked freelist based on a random pre-computed sequence */ |
| 1553 | static bool shuffle_freelist(struct kmem_cache *s, struct page *page) |
| 1554 | { |
| 1555 | void *start; |
| 1556 | void *cur; |
| 1557 | void *next; |
| 1558 | unsigned long idx, pos, page_limit, freelist_count; |
| 1559 | |
| 1560 | if (page->objects < 2 || !s->random_seq) |
| 1561 | return false; |
| 1562 | |
| 1563 | freelist_count = oo_objects(s->oo); |
| 1564 | pos = get_random_int() % freelist_count; |
| 1565 | |
| 1566 | page_limit = page->objects * s->size; |
| 1567 | start = fixup_red_left(s, page_address(page)); |
| 1568 | |
| 1569 | /* First entry is used as the base of the freelist */ |
| 1570 | cur = next_freelist_entry(s, page, &pos, start, page_limit, |
| 1571 | freelist_count); |
| 1572 | cur = setup_object(s, page, cur); |
| 1573 | page->freelist = cur; |
| 1574 | |
| 1575 | for (idx = 1; idx < page->objects; idx++) { |
| 1576 | next = next_freelist_entry(s, page, &pos, start, page_limit, |
| 1577 | freelist_count); |
| 1578 | next = setup_object(s, page, next); |
| 1579 | set_freepointer(s, cur, next); |
| 1580 | cur = next; |
| 1581 | } |
| 1582 | set_freepointer(s, cur, NULL); |
| 1583 | |
| 1584 | return true; |
| 1585 | } |
| 1586 | #else |
| 1587 | static inline int init_cache_random_seq(struct kmem_cache *s) |
| 1588 | { |
| 1589 | return 0; |
| 1590 | } |
| 1591 | static inline void init_freelist_randomization(void) { } |
| 1592 | static inline bool shuffle_freelist(struct kmem_cache *s, struct page *page) |
| 1593 | { |
| 1594 | return false; |
| 1595 | } |
| 1596 | #endif /* CONFIG_SLAB_FREELIST_RANDOM */ |
| 1597 | |
| 1598 | static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node) |
| 1599 | { |
| 1600 | struct page *page; |
| 1601 | struct kmem_cache_order_objects oo = s->oo; |
| 1602 | gfp_t alloc_gfp; |
| 1603 | void *start, *p, *next; |
| 1604 | int idx, order; |
| 1605 | bool shuffle; |
| 1606 | |
| 1607 | flags &= gfp_allowed_mask; |
| 1608 | |
| 1609 | if (gfpflags_allow_blocking(flags)) |
| 1610 | local_irq_enable(); |
| 1611 | |
| 1612 | flags |= s->allocflags; |
| 1613 | |
| 1614 | /* |
| 1615 | * Let the initial higher-order allocation fail under memory pressure |
| 1616 | * so we fall-back to the minimum order allocation. |
| 1617 | */ |
| 1618 | alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL; |
| 1619 | if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min)) |
| 1620 | alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~(__GFP_RECLAIM|__GFP_NOFAIL); |
| 1621 | |
| 1622 | page = alloc_slab_page(s, alloc_gfp, node, oo); |
| 1623 | if (unlikely(!page)) { |
| 1624 | oo = s->min; |
| 1625 | alloc_gfp = flags; |
| 1626 | /* |
| 1627 | * Allocation may have failed due to fragmentation. |
| 1628 | * Try a lower order alloc if possible |
| 1629 | */ |
| 1630 | page = alloc_slab_page(s, alloc_gfp, node, oo); |
| 1631 | if (unlikely(!page)) |
| 1632 | goto out; |
| 1633 | stat(s, ORDER_FALLBACK); |
| 1634 | } |
| 1635 | |
| 1636 | page->objects = oo_objects(oo); |
| 1637 | |
| 1638 | order = compound_order(page); |
| 1639 | page->slab_cache = s; |
| 1640 | __SetPageSlab(page); |
| 1641 | if (page_is_pfmemalloc(page)) |
| 1642 | SetPageSlabPfmemalloc(page); |
| 1643 | |
| 1644 | start = page_address(page); |
| 1645 | |
| 1646 | if (unlikely(s->flags & SLAB_POISON)) |
| 1647 | memset(start, POISON_INUSE, PAGE_SIZE << order); |
| 1648 | |
| 1649 | kasan_poison_slab(page); |
| 1650 | |
| 1651 | shuffle = shuffle_freelist(s, page); |
| 1652 | |
| 1653 | if (!shuffle) { |
| 1654 | for_each_object_idx(p, idx, s, start, page->objects) { |
| 1655 | if (likely(idx < page->objects)) { |
| 1656 | next = p + s->size; |
| 1657 | next = setup_object(s, page, next); |
| 1658 | set_freepointer(s, p, next); |
| 1659 | } else |
| 1660 | set_freepointer(s, p, NULL); |
| 1661 | } |
| 1662 | start = fixup_red_left(s, start); |
| 1663 | start = setup_object(s, page, start); |
| 1664 | page->freelist = start; |
| 1665 | } |
| 1666 | |
| 1667 | page->inuse = page->objects; |
| 1668 | page->frozen = 1; |
| 1669 | |
| 1670 | out: |
| 1671 | if (gfpflags_allow_blocking(flags)) |
| 1672 | local_irq_disable(); |
| 1673 | if (!page) |
| 1674 | return NULL; |
| 1675 | |
| 1676 | mod_lruvec_page_state(page, |
| 1677 | (s->flags & SLAB_RECLAIM_ACCOUNT) ? |
| 1678 | NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, |
| 1679 | 1 << oo_order(oo)); |
| 1680 | |
| 1681 | inc_slabs_node(s, page_to_nid(page), page->objects); |
| 1682 | |
| 1683 | return page; |
| 1684 | } |
| 1685 | |
| 1686 | static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node) |
| 1687 | { |
| 1688 | if (unlikely(flags & GFP_SLAB_BUG_MASK)) { |
| 1689 | gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; |
| 1690 | flags &= ~GFP_SLAB_BUG_MASK; |
| 1691 | pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", |
| 1692 | invalid_mask, &invalid_mask, flags, &flags); |
| 1693 | dump_stack(); |
| 1694 | } |
| 1695 | |
| 1696 | return allocate_slab(s, |
| 1697 | flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node); |
| 1698 | } |
| 1699 | |
| 1700 | static void __free_slab(struct kmem_cache *s, struct page *page) |
| 1701 | { |
| 1702 | int order = compound_order(page); |
| 1703 | int pages = 1 << order; |
| 1704 | |
| 1705 | if (s->flags & SLAB_CONSISTENCY_CHECKS) { |
| 1706 | void *p; |
| 1707 | |
| 1708 | slab_pad_check(s, page); |
| 1709 | for_each_object(p, s, page_address(page), |
| 1710 | page->objects) |
| 1711 | check_object(s, page, p, SLUB_RED_INACTIVE); |
| 1712 | } |
| 1713 | |
| 1714 | mod_lruvec_page_state(page, |
| 1715 | (s->flags & SLAB_RECLAIM_ACCOUNT) ? |
| 1716 | NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE, |
| 1717 | -pages); |
| 1718 | |
| 1719 | __ClearPageSlabPfmemalloc(page); |
| 1720 | __ClearPageSlab(page); |
| 1721 | |
| 1722 | page->mapping = NULL; |
| 1723 | if (current->reclaim_state) |
| 1724 | current->reclaim_state->reclaimed_slab += pages; |
| 1725 | memcg_uncharge_slab(page, order, s); |
| 1726 | __free_pages(page, order); |
| 1727 | } |
| 1728 | |
| 1729 | static void rcu_free_slab(struct rcu_head *h) |
| 1730 | { |
| 1731 | struct page *page = container_of(h, struct page, rcu_head); |
| 1732 | |
| 1733 | __free_slab(page->slab_cache, page); |
| 1734 | } |
| 1735 | |
| 1736 | static void free_slab(struct kmem_cache *s, struct page *page) |
| 1737 | { |
| 1738 | if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) { |
| 1739 | call_rcu(&page->rcu_head, rcu_free_slab); |
| 1740 | } else |
| 1741 | __free_slab(s, page); |
| 1742 | } |
| 1743 | |
| 1744 | static void discard_slab(struct kmem_cache *s, struct page *page) |
| 1745 | { |
| 1746 | dec_slabs_node(s, page_to_nid(page), page->objects); |
| 1747 | free_slab(s, page); |
| 1748 | } |
| 1749 | |
| 1750 | /* |
| 1751 | * Management of partially allocated slabs. |
| 1752 | */ |
| 1753 | static inline void |
| 1754 | __add_partial(struct kmem_cache_node *n, struct page *page, int tail) |
| 1755 | { |
| 1756 | n->nr_partial++; |
| 1757 | if (tail == DEACTIVATE_TO_TAIL) |
| 1758 | list_add_tail(&page->lru, &n->partial); |
| 1759 | else |
| 1760 | list_add(&page->lru, &n->partial); |
| 1761 | } |
| 1762 | |
| 1763 | static inline void add_partial(struct kmem_cache_node *n, |
| 1764 | struct page *page, int tail) |
| 1765 | { |
| 1766 | lockdep_assert_held(&n->list_lock); |
| 1767 | __add_partial(n, page, tail); |
| 1768 | } |
| 1769 | |
| 1770 | static inline void remove_partial(struct kmem_cache_node *n, |
| 1771 | struct page *page) |
| 1772 | { |
| 1773 | lockdep_assert_held(&n->list_lock); |
| 1774 | list_del(&page->lru); |
| 1775 | n->nr_partial--; |
| 1776 | } |
| 1777 | |
| 1778 | /* |
| 1779 | * Remove slab from the partial list, freeze it and |
| 1780 | * return the pointer to the freelist. |
| 1781 | * |
| 1782 | * Returns a list of objects or NULL if it fails. |
| 1783 | */ |
| 1784 | static inline void *acquire_slab(struct kmem_cache *s, |
| 1785 | struct kmem_cache_node *n, struct page *page, |
| 1786 | int mode, int *objects) |
| 1787 | { |
| 1788 | void *freelist; |
| 1789 | unsigned long counters; |
| 1790 | struct page new; |
| 1791 | |
| 1792 | lockdep_assert_held(&n->list_lock); |
| 1793 | |
| 1794 | /* |
| 1795 | * Zap the freelist and set the frozen bit. |
| 1796 | * The old freelist is the list of objects for the |
| 1797 | * per cpu allocation list. |
| 1798 | */ |
| 1799 | freelist = page->freelist; |
| 1800 | counters = page->counters; |
| 1801 | new.counters = counters; |
| 1802 | *objects = new.objects - new.inuse; |
| 1803 | if (mode) { |
| 1804 | new.inuse = page->objects; |
| 1805 | new.freelist = NULL; |
| 1806 | } else { |
| 1807 | new.freelist = freelist; |
| 1808 | } |
| 1809 | |
| 1810 | VM_BUG_ON(new.frozen); |
| 1811 | new.frozen = 1; |
| 1812 | |
| 1813 | if (!__cmpxchg_double_slab(s, page, |
| 1814 | freelist, counters, |
| 1815 | new.freelist, new.counters, |
| 1816 | "acquire_slab")) |
| 1817 | return NULL; |
| 1818 | |
| 1819 | remove_partial(n, page); |
| 1820 | WARN_ON(!freelist); |
| 1821 | return freelist; |
| 1822 | } |
| 1823 | |
| 1824 | static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain); |
| 1825 | static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags); |
| 1826 | |
| 1827 | /* |
| 1828 | * Try to allocate a partial slab from a specific node. |
| 1829 | */ |
| 1830 | static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n, |
| 1831 | struct kmem_cache_cpu *c, gfp_t flags) |
| 1832 | { |
| 1833 | struct page *page, *page2; |
| 1834 | void *object = NULL; |
| 1835 | unsigned int available = 0; |
| 1836 | int objects; |
| 1837 | |
| 1838 | /* |
| 1839 | * Racy check. If we mistakenly see no partial slabs then we |
| 1840 | * just allocate an empty slab. If we mistakenly try to get a |
| 1841 | * partial slab and there is none available then get_partials() |
| 1842 | * will return NULL. |
| 1843 | */ |
| 1844 | if (!n || !n->nr_partial) |
| 1845 | return NULL; |
| 1846 | |
| 1847 | spin_lock(&n->list_lock); |
| 1848 | list_for_each_entry_safe(page, page2, &n->partial, lru) { |
| 1849 | void *t; |
| 1850 | |
| 1851 | if (!pfmemalloc_match(page, flags)) |
| 1852 | continue; |
| 1853 | |
| 1854 | t = acquire_slab(s, n, page, object == NULL, &objects); |
| 1855 | if (!t) |
| 1856 | break; |
| 1857 | |
| 1858 | available += objects; |
| 1859 | if (!object) { |
| 1860 | c->page = page; |
| 1861 | stat(s, ALLOC_FROM_PARTIAL); |
| 1862 | object = t; |
| 1863 | } else { |
| 1864 | put_cpu_partial(s, page, 0); |
| 1865 | stat(s, CPU_PARTIAL_NODE); |
| 1866 | } |
| 1867 | if (!kmem_cache_has_cpu_partial(s) |
| 1868 | || available > slub_cpu_partial(s) / 2) |
| 1869 | break; |
| 1870 | |
| 1871 | } |
| 1872 | spin_unlock(&n->list_lock); |
| 1873 | return object; |
| 1874 | } |
| 1875 | |
| 1876 | /* |
| 1877 | * Get a page from somewhere. Search in increasing NUMA distances. |
| 1878 | */ |
| 1879 | static void *get_any_partial(struct kmem_cache *s, gfp_t flags, |
| 1880 | struct kmem_cache_cpu *c) |
| 1881 | { |
| 1882 | #ifdef CONFIG_NUMA |
| 1883 | struct zonelist *zonelist; |
| 1884 | struct zoneref *z; |
| 1885 | struct zone *zone; |
| 1886 | enum zone_type high_zoneidx = gfp_zone(flags); |
| 1887 | void *object; |
| 1888 | unsigned int cpuset_mems_cookie; |
| 1889 | |
| 1890 | /* |
| 1891 | * The defrag ratio allows a configuration of the tradeoffs between |
| 1892 | * inter node defragmentation and node local allocations. A lower |
| 1893 | * defrag_ratio increases the tendency to do local allocations |
| 1894 | * instead of attempting to obtain partial slabs from other nodes. |
| 1895 | * |
| 1896 | * If the defrag_ratio is set to 0 then kmalloc() always |
| 1897 | * returns node local objects. If the ratio is higher then kmalloc() |
| 1898 | * may return off node objects because partial slabs are obtained |
| 1899 | * from other nodes and filled up. |
| 1900 | * |
| 1901 | * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100 |
| 1902 | * (which makes defrag_ratio = 1000) then every (well almost) |
| 1903 | * allocation will first attempt to defrag slab caches on other nodes. |
| 1904 | * This means scanning over all nodes to look for partial slabs which |
| 1905 | * may be expensive if we do it every time we are trying to find a slab |
| 1906 | * with available objects. |
| 1907 | */ |
| 1908 | if (!s->remote_node_defrag_ratio || |
| 1909 | get_cycles() % 1024 > s->remote_node_defrag_ratio) |
| 1910 | return NULL; |
| 1911 | |
| 1912 | do { |
| 1913 | cpuset_mems_cookie = read_mems_allowed_begin(); |
| 1914 | zonelist = node_zonelist(mempolicy_slab_node(), flags); |
| 1915 | for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { |
| 1916 | struct kmem_cache_node *n; |
| 1917 | |
| 1918 | n = get_node(s, zone_to_nid(zone)); |
| 1919 | |
| 1920 | if (n && cpuset_zone_allowed(zone, flags) && |
| 1921 | n->nr_partial > s->min_partial) { |
| 1922 | object = get_partial_node(s, n, c, flags); |
| 1923 | if (object) { |
| 1924 | /* |
| 1925 | * Don't check read_mems_allowed_retry() |
| 1926 | * here - if mems_allowed was updated in |
| 1927 | * parallel, that was a harmless race |
| 1928 | * between allocation and the cpuset |
| 1929 | * update |
| 1930 | */ |
| 1931 | return object; |
| 1932 | } |
| 1933 | } |
| 1934 | } |
| 1935 | } while (read_mems_allowed_retry(cpuset_mems_cookie)); |
| 1936 | #endif |
| 1937 | return NULL; |
| 1938 | } |
| 1939 | |
| 1940 | /* |
| 1941 | * Get a partial page, lock it and return it. |
| 1942 | */ |
| 1943 | static void *get_partial(struct kmem_cache *s, gfp_t flags, int node, |
| 1944 | struct kmem_cache_cpu *c) |
| 1945 | { |
| 1946 | void *object; |
| 1947 | int searchnode = node; |
| 1948 | |
| 1949 | if (node == NUMA_NO_NODE) |
| 1950 | searchnode = numa_mem_id(); |
| 1951 | else if (!node_present_pages(node)) |
| 1952 | searchnode = node_to_mem_node(node); |
| 1953 | |
| 1954 | object = get_partial_node(s, get_node(s, searchnode), c, flags); |
| 1955 | if (object || node != NUMA_NO_NODE) |
| 1956 | return object; |
| 1957 | |
| 1958 | return get_any_partial(s, flags, c); |
| 1959 | } |
| 1960 | |
| 1961 | #ifdef CONFIG_PREEMPT |
| 1962 | /* |
| 1963 | * Calculate the next globally unique transaction for disambiguiation |
| 1964 | * during cmpxchg. The transactions start with the cpu number and are then |
| 1965 | * incremented by CONFIG_NR_CPUS. |
| 1966 | */ |
| 1967 | #define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS) |
| 1968 | #else |
| 1969 | /* |
| 1970 | * No preemption supported therefore also no need to check for |
| 1971 | * different cpus. |
| 1972 | */ |
| 1973 | #define TID_STEP 1 |
| 1974 | #endif |
| 1975 | |
| 1976 | static inline unsigned long next_tid(unsigned long tid) |
| 1977 | { |
| 1978 | return tid + TID_STEP; |
| 1979 | } |
| 1980 | |
| 1981 | static inline unsigned int tid_to_cpu(unsigned long tid) |
| 1982 | { |
| 1983 | return tid % TID_STEP; |
| 1984 | } |
| 1985 | |
| 1986 | static inline unsigned long tid_to_event(unsigned long tid) |
| 1987 | { |
| 1988 | return tid / TID_STEP; |
| 1989 | } |
| 1990 | |
| 1991 | static inline unsigned int init_tid(int cpu) |
| 1992 | { |
| 1993 | return cpu; |
| 1994 | } |
| 1995 | |
| 1996 | static inline void note_cmpxchg_failure(const char *n, |
| 1997 | const struct kmem_cache *s, unsigned long tid) |
| 1998 | { |
| 1999 | #ifdef SLUB_DEBUG_CMPXCHG |
| 2000 | unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid); |
| 2001 | |
| 2002 | pr_info("%s %s: cmpxchg redo ", n, s->name); |
| 2003 | |
| 2004 | #ifdef CONFIG_PREEMPT |
| 2005 | if (tid_to_cpu(tid) != tid_to_cpu(actual_tid)) |
| 2006 | pr_warn("due to cpu change %d -> %d\n", |
| 2007 | tid_to_cpu(tid), tid_to_cpu(actual_tid)); |
| 2008 | else |
| 2009 | #endif |
| 2010 | if (tid_to_event(tid) != tid_to_event(actual_tid)) |
| 2011 | pr_warn("due to cpu running other code. Event %ld->%ld\n", |
| 2012 | tid_to_event(tid), tid_to_event(actual_tid)); |
| 2013 | else |
| 2014 | pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n", |
| 2015 | actual_tid, tid, next_tid(tid)); |
| 2016 | #endif |
| 2017 | stat(s, CMPXCHG_DOUBLE_CPU_FAIL); |
| 2018 | } |
| 2019 | |
| 2020 | static void init_kmem_cache_cpus(struct kmem_cache *s) |
| 2021 | { |
| 2022 | int cpu; |
| 2023 | |
| 2024 | for_each_possible_cpu(cpu) |
| 2025 | per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu); |
| 2026 | } |
| 2027 | |
| 2028 | /* |
| 2029 | * Remove the cpu slab |
| 2030 | */ |
| 2031 | static void deactivate_slab(struct kmem_cache *s, struct page *page, |
| 2032 | void *freelist, struct kmem_cache_cpu *c) |
| 2033 | { |
| 2034 | enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE }; |
| 2035 | struct kmem_cache_node *n = get_node(s, page_to_nid(page)); |
| 2036 | int lock = 0; |
| 2037 | enum slab_modes l = M_NONE, m = M_NONE; |
| 2038 | void *nextfree; |
| 2039 | int tail = DEACTIVATE_TO_HEAD; |
| 2040 | struct page new; |
| 2041 | struct page old; |
| 2042 | |
| 2043 | if (page->freelist) { |
| 2044 | stat(s, DEACTIVATE_REMOTE_FREES); |
| 2045 | tail = DEACTIVATE_TO_TAIL; |
| 2046 | } |
| 2047 | |
| 2048 | /* |
| 2049 | * Stage one: Free all available per cpu objects back |
| 2050 | * to the page freelist while it is still frozen. Leave the |
| 2051 | * last one. |
| 2052 | * |
| 2053 | * There is no need to take the list->lock because the page |
| 2054 | * is still frozen. |
| 2055 | */ |
| 2056 | while (freelist && (nextfree = get_freepointer(s, freelist))) { |
| 2057 | void *prior; |
| 2058 | unsigned long counters; |
| 2059 | |
| 2060 | do { |
| 2061 | prior = page->freelist; |
| 2062 | counters = page->counters; |
| 2063 | set_freepointer(s, freelist, prior); |
| 2064 | new.counters = counters; |
| 2065 | new.inuse--; |
| 2066 | VM_BUG_ON(!new.frozen); |
| 2067 | |
| 2068 | } while (!__cmpxchg_double_slab(s, page, |
| 2069 | prior, counters, |
| 2070 | freelist, new.counters, |
| 2071 | "drain percpu freelist")); |
| 2072 | |
| 2073 | freelist = nextfree; |
| 2074 | } |
| 2075 | |
| 2076 | /* |
| 2077 | * Stage two: Ensure that the page is unfrozen while the |
| 2078 | * list presence reflects the actual number of objects |
| 2079 | * during unfreeze. |
| 2080 | * |
| 2081 | * We setup the list membership and then perform a cmpxchg |
| 2082 | * with the count. If there is a mismatch then the page |
| 2083 | * is not unfrozen but the page is on the wrong list. |
| 2084 | * |
| 2085 | * Then we restart the process which may have to remove |
| 2086 | * the page from the list that we just put it on again |
| 2087 | * because the number of objects in the slab may have |
| 2088 | * changed. |
| 2089 | */ |
| 2090 | redo: |
| 2091 | |
| 2092 | old.freelist = page->freelist; |
| 2093 | old.counters = page->counters; |
| 2094 | VM_BUG_ON(!old.frozen); |
| 2095 | |
| 2096 | /* Determine target state of the slab */ |
| 2097 | new.counters = old.counters; |
| 2098 | if (freelist) { |
| 2099 | new.inuse--; |
| 2100 | set_freepointer(s, freelist, old.freelist); |
| 2101 | new.freelist = freelist; |
| 2102 | } else |
| 2103 | new.freelist = old.freelist; |
| 2104 | |
| 2105 | new.frozen = 0; |
| 2106 | |
| 2107 | if (!new.inuse && n->nr_partial >= s->min_partial) |
| 2108 | m = M_FREE; |
| 2109 | else if (new.freelist) { |
| 2110 | m = M_PARTIAL; |
| 2111 | if (!lock) { |
| 2112 | lock = 1; |
| 2113 | /* |
| 2114 | * Taking the spinlock removes the possiblity |
| 2115 | * that acquire_slab() will see a slab page that |
| 2116 | * is frozen |
| 2117 | */ |
| 2118 | spin_lock(&n->list_lock); |
| 2119 | } |
| 2120 | } else { |
| 2121 | m = M_FULL; |
| 2122 | if (kmem_cache_debug(s) && !lock) { |
| 2123 | lock = 1; |
| 2124 | /* |
| 2125 | * This also ensures that the scanning of full |
| 2126 | * slabs from diagnostic functions will not see |
| 2127 | * any frozen slabs. |
| 2128 | */ |
| 2129 | spin_lock(&n->list_lock); |
| 2130 | } |
| 2131 | } |
| 2132 | |
| 2133 | if (l != m) { |
| 2134 | if (l == M_PARTIAL) |
| 2135 | remove_partial(n, page); |
| 2136 | else if (l == M_FULL) |
| 2137 | remove_full(s, n, page); |
| 2138 | |
| 2139 | if (m == M_PARTIAL) |
| 2140 | add_partial(n, page, tail); |
| 2141 | else if (m == M_FULL) |
| 2142 | add_full(s, n, page); |
| 2143 | } |
| 2144 | |
| 2145 | l = m; |
| 2146 | if (!__cmpxchg_double_slab(s, page, |
| 2147 | old.freelist, old.counters, |
| 2148 | new.freelist, new.counters, |
| 2149 | "unfreezing slab")) |
| 2150 | goto redo; |
| 2151 | |
| 2152 | if (lock) |
| 2153 | spin_unlock(&n->list_lock); |
| 2154 | |
| 2155 | if (m == M_PARTIAL) |
| 2156 | stat(s, tail); |
| 2157 | else if (m == M_FULL) |
| 2158 | stat(s, DEACTIVATE_FULL); |
| 2159 | else if (m == M_FREE) { |
| 2160 | stat(s, DEACTIVATE_EMPTY); |
| 2161 | discard_slab(s, page); |
| 2162 | stat(s, FREE_SLAB); |
| 2163 | } |
| 2164 | |
| 2165 | c->page = NULL; |
| 2166 | c->freelist = NULL; |
| 2167 | } |
| 2168 | |
| 2169 | /* |
| 2170 | * Unfreeze all the cpu partial slabs. |
| 2171 | * |
| 2172 | * This function must be called with interrupts disabled |
| 2173 | * for the cpu using c (or some other guarantee must be there |
| 2174 | * to guarantee no concurrent accesses). |
| 2175 | */ |
| 2176 | static void unfreeze_partials(struct kmem_cache *s, |
| 2177 | struct kmem_cache_cpu *c) |
| 2178 | { |
| 2179 | #ifdef CONFIG_SLUB_CPU_PARTIAL |
| 2180 | struct kmem_cache_node *n = NULL, *n2 = NULL; |
| 2181 | struct page *page, *discard_page = NULL; |
| 2182 | |
| 2183 | while ((page = c->partial)) { |
| 2184 | struct page new; |
| 2185 | struct page old; |
| 2186 | |
| 2187 | c->partial = page->next; |
| 2188 | |
| 2189 | n2 = get_node(s, page_to_nid(page)); |
| 2190 | if (n != n2) { |
| 2191 | if (n) |
| 2192 | spin_unlock(&n->list_lock); |
| 2193 | |
| 2194 | n = n2; |
| 2195 | spin_lock(&n->list_lock); |
| 2196 | } |
| 2197 | |
| 2198 | do { |
| 2199 | |
| 2200 | old.freelist = page->freelist; |
| 2201 | old.counters = page->counters; |
| 2202 | VM_BUG_ON(!old.frozen); |
| 2203 | |
| 2204 | new.counters = old.counters; |
| 2205 | new.freelist = old.freelist; |
| 2206 | |
| 2207 | new.frozen = 0; |
| 2208 | |
| 2209 | } while (!__cmpxchg_double_slab(s, page, |
| 2210 | old.freelist, old.counters, |
| 2211 | new.freelist, new.counters, |
| 2212 | "unfreezing slab")); |
| 2213 | |
| 2214 | if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) { |
| 2215 | page->next = discard_page; |
| 2216 | discard_page = page; |
| 2217 | } else { |
| 2218 | add_partial(n, page, DEACTIVATE_TO_TAIL); |
| 2219 | stat(s, FREE_ADD_PARTIAL); |
| 2220 | } |
| 2221 | } |
| 2222 | |
| 2223 | if (n) |
| 2224 | spin_unlock(&n->list_lock); |
| 2225 | |
| 2226 | while (discard_page) { |
| 2227 | page = discard_page; |
| 2228 | discard_page = discard_page->next; |
| 2229 | |
| 2230 | stat(s, DEACTIVATE_EMPTY); |
| 2231 | discard_slab(s, page); |
| 2232 | stat(s, FREE_SLAB); |
| 2233 | } |
| 2234 | #endif |
| 2235 | } |
| 2236 | |
| 2237 | /* |
| 2238 | * Put a page that was just frozen (in __slab_free) into a partial page |
| 2239 | * slot if available. |
| 2240 | * |
| 2241 | * If we did not find a slot then simply move all the partials to the |
| 2242 | * per node partial list. |
| 2243 | */ |
| 2244 | static void put_cpu_partial(struct kmem_cache *s, struct page *page, int drain) |
| 2245 | { |
| 2246 | #ifdef CONFIG_SLUB_CPU_PARTIAL |
| 2247 | struct page *oldpage; |
| 2248 | int pages; |
| 2249 | int pobjects; |
| 2250 | |
| 2251 | preempt_disable(); |
| 2252 | do { |
| 2253 | pages = 0; |
| 2254 | pobjects = 0; |
| 2255 | oldpage = this_cpu_read(s->cpu_slab->partial); |
| 2256 | |
| 2257 | if (oldpage) { |
| 2258 | pobjects = oldpage->pobjects; |
| 2259 | pages = oldpage->pages; |
| 2260 | if (drain && pobjects > s->cpu_partial) { |
| 2261 | unsigned long flags; |
| 2262 | /* |
| 2263 | * partial array is full. Move the existing |
| 2264 | * set to the per node partial list. |
| 2265 | */ |
| 2266 | local_irq_save(flags); |
| 2267 | unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); |
| 2268 | local_irq_restore(flags); |
| 2269 | oldpage = NULL; |
| 2270 | pobjects = 0; |
| 2271 | pages = 0; |
| 2272 | stat(s, CPU_PARTIAL_DRAIN); |
| 2273 | } |
| 2274 | } |
| 2275 | |
| 2276 | pages++; |
| 2277 | pobjects += page->objects - page->inuse; |
| 2278 | |
| 2279 | page->pages = pages; |
| 2280 | page->pobjects = pobjects; |
| 2281 | page->next = oldpage; |
| 2282 | |
| 2283 | } while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) |
| 2284 | != oldpage); |
| 2285 | if (unlikely(!s->cpu_partial)) { |
| 2286 | unsigned long flags; |
| 2287 | |
| 2288 | local_irq_save(flags); |
| 2289 | unfreeze_partials(s, this_cpu_ptr(s->cpu_slab)); |
| 2290 | local_irq_restore(flags); |
| 2291 | } |
| 2292 | preempt_enable(); |
| 2293 | #endif |
| 2294 | } |
| 2295 | |
| 2296 | static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c) |
| 2297 | { |
| 2298 | stat(s, CPUSLAB_FLUSH); |
| 2299 | deactivate_slab(s, c->page, c->freelist, c); |
| 2300 | |
| 2301 | c->tid = next_tid(c->tid); |
| 2302 | } |
| 2303 | |
| 2304 | /* |
| 2305 | * Flush cpu slab. |
| 2306 | * |
| 2307 | * Called from IPI handler with interrupts disabled. |
| 2308 | */ |
| 2309 | static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu) |
| 2310 | { |
| 2311 | struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); |
| 2312 | |
| 2313 | if (c->page) |
| 2314 | flush_slab(s, c); |
| 2315 | |
| 2316 | unfreeze_partials(s, c); |
| 2317 | } |
| 2318 | |
| 2319 | static void flush_cpu_slab(void *d) |
| 2320 | { |
| 2321 | struct kmem_cache *s = d; |
| 2322 | |
| 2323 | __flush_cpu_slab(s, smp_processor_id()); |
| 2324 | } |
| 2325 | |
| 2326 | static bool has_cpu_slab(int cpu, void *info) |
| 2327 | { |
| 2328 | struct kmem_cache *s = info; |
| 2329 | struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu); |
| 2330 | |
| 2331 | return c->page || slub_percpu_partial(c); |
| 2332 | } |
| 2333 | |
| 2334 | static void flush_all(struct kmem_cache *s) |
| 2335 | { |
| 2336 | on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC); |
| 2337 | } |
| 2338 | |
| 2339 | /* |
| 2340 | * Use the cpu notifier to insure that the cpu slabs are flushed when |
| 2341 | * necessary. |
| 2342 | */ |
| 2343 | static int slub_cpu_dead(unsigned int cpu) |
| 2344 | { |
| 2345 | struct kmem_cache *s; |
| 2346 | unsigned long flags; |
| 2347 | |
| 2348 | mutex_lock(&slab_mutex); |
| 2349 | list_for_each_entry(s, &slab_caches, list) { |
| 2350 | local_irq_save(flags); |
| 2351 | __flush_cpu_slab(s, cpu); |
| 2352 | local_irq_restore(flags); |
| 2353 | } |
| 2354 | mutex_unlock(&slab_mutex); |
| 2355 | return 0; |
| 2356 | } |
| 2357 | |
| 2358 | /* |
| 2359 | * Check if the objects in a per cpu structure fit numa |
| 2360 | * locality expectations. |
| 2361 | */ |
| 2362 | static inline int node_match(struct page *page, int node) |
| 2363 | { |
| 2364 | #ifdef CONFIG_NUMA |
| 2365 | if (node != NUMA_NO_NODE && page_to_nid(page) != node) |
| 2366 | return 0; |
| 2367 | #endif |
| 2368 | return 1; |
| 2369 | } |
| 2370 | |
| 2371 | #ifdef CONFIG_SLUB_DEBUG |
| 2372 | static int count_free(struct page *page) |
| 2373 | { |
| 2374 | return page->objects - page->inuse; |
| 2375 | } |
| 2376 | |
| 2377 | static inline unsigned long node_nr_objs(struct kmem_cache_node *n) |
| 2378 | { |
| 2379 | return atomic_long_read(&n->total_objects); |
| 2380 | } |
| 2381 | #endif /* CONFIG_SLUB_DEBUG */ |
| 2382 | |
| 2383 | #if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS) |
| 2384 | static unsigned long count_partial(struct kmem_cache_node *n, |
| 2385 | int (*get_count)(struct page *)) |
| 2386 | { |
| 2387 | unsigned long flags; |
| 2388 | unsigned long x = 0; |
| 2389 | struct page *page; |
| 2390 | |
| 2391 | spin_lock_irqsave(&n->list_lock, flags); |
| 2392 | list_for_each_entry(page, &n->partial, lru) |
| 2393 | x += get_count(page); |
| 2394 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 2395 | return x; |
| 2396 | } |
| 2397 | #endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */ |
| 2398 | |
| 2399 | static noinline void |
| 2400 | slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid) |
| 2401 | { |
| 2402 | #ifdef CONFIG_SLUB_DEBUG |
| 2403 | static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL, |
| 2404 | DEFAULT_RATELIMIT_BURST); |
| 2405 | int node; |
| 2406 | struct kmem_cache_node *n; |
| 2407 | |
| 2408 | if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs)) |
| 2409 | return; |
| 2410 | |
| 2411 | pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n", |
| 2412 | nid, gfpflags, &gfpflags); |
| 2413 | pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n", |
| 2414 | s->name, s->object_size, s->size, oo_order(s->oo), |
| 2415 | oo_order(s->min)); |
| 2416 | |
| 2417 | if (oo_order(s->min) > get_order(s->object_size)) |
| 2418 | pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n", |
| 2419 | s->name); |
| 2420 | |
| 2421 | for_each_kmem_cache_node(s, node, n) { |
| 2422 | unsigned long nr_slabs; |
| 2423 | unsigned long nr_objs; |
| 2424 | unsigned long nr_free; |
| 2425 | |
| 2426 | nr_free = count_partial(n, count_free); |
| 2427 | nr_slabs = node_nr_slabs(n); |
| 2428 | nr_objs = node_nr_objs(n); |
| 2429 | |
| 2430 | pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n", |
| 2431 | node, nr_slabs, nr_objs, nr_free); |
| 2432 | } |
| 2433 | #endif |
| 2434 | } |
| 2435 | |
| 2436 | static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags, |
| 2437 | int node, struct kmem_cache_cpu **pc) |
| 2438 | { |
| 2439 | void *freelist; |
| 2440 | struct kmem_cache_cpu *c = *pc; |
| 2441 | struct page *page; |
| 2442 | |
| 2443 | WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO)); |
| 2444 | |
| 2445 | freelist = get_partial(s, flags, node, c); |
| 2446 | |
| 2447 | if (freelist) |
| 2448 | return freelist; |
| 2449 | |
| 2450 | page = new_slab(s, flags, node); |
| 2451 | if (page) { |
| 2452 | c = raw_cpu_ptr(s->cpu_slab); |
| 2453 | if (c->page) |
| 2454 | flush_slab(s, c); |
| 2455 | |
| 2456 | /* |
| 2457 | * No other reference to the page yet so we can |
| 2458 | * muck around with it freely without cmpxchg |
| 2459 | */ |
| 2460 | freelist = page->freelist; |
| 2461 | page->freelist = NULL; |
| 2462 | |
| 2463 | stat(s, ALLOC_SLAB); |
| 2464 | c->page = page; |
| 2465 | *pc = c; |
| 2466 | } else |
| 2467 | freelist = NULL; |
| 2468 | |
| 2469 | return freelist; |
| 2470 | } |
| 2471 | |
| 2472 | static inline bool pfmemalloc_match(struct page *page, gfp_t gfpflags) |
| 2473 | { |
| 2474 | if (unlikely(PageSlabPfmemalloc(page))) |
| 2475 | return gfp_pfmemalloc_allowed(gfpflags); |
| 2476 | |
| 2477 | return true; |
| 2478 | } |
| 2479 | |
| 2480 | /* |
| 2481 | * Check the page->freelist of a page and either transfer the freelist to the |
| 2482 | * per cpu freelist or deactivate the page. |
| 2483 | * |
| 2484 | * The page is still frozen if the return value is not NULL. |
| 2485 | * |
| 2486 | * If this function returns NULL then the page has been unfrozen. |
| 2487 | * |
| 2488 | * This function must be called with interrupt disabled. |
| 2489 | */ |
| 2490 | static inline void *get_freelist(struct kmem_cache *s, struct page *page) |
| 2491 | { |
| 2492 | struct page new; |
| 2493 | unsigned long counters; |
| 2494 | void *freelist; |
| 2495 | |
| 2496 | do { |
| 2497 | freelist = page->freelist; |
| 2498 | counters = page->counters; |
| 2499 | |
| 2500 | new.counters = counters; |
| 2501 | VM_BUG_ON(!new.frozen); |
| 2502 | |
| 2503 | new.inuse = page->objects; |
| 2504 | new.frozen = freelist != NULL; |
| 2505 | |
| 2506 | } while (!__cmpxchg_double_slab(s, page, |
| 2507 | freelist, counters, |
| 2508 | NULL, new.counters, |
| 2509 | "get_freelist")); |
| 2510 | |
| 2511 | return freelist; |
| 2512 | } |
| 2513 | |
| 2514 | /* |
| 2515 | * Slow path. The lockless freelist is empty or we need to perform |
| 2516 | * debugging duties. |
| 2517 | * |
| 2518 | * Processing is still very fast if new objects have been freed to the |
| 2519 | * regular freelist. In that case we simply take over the regular freelist |
| 2520 | * as the lockless freelist and zap the regular freelist. |
| 2521 | * |
| 2522 | * If that is not working then we fall back to the partial lists. We take the |
| 2523 | * first element of the freelist as the object to allocate now and move the |
| 2524 | * rest of the freelist to the lockless freelist. |
| 2525 | * |
| 2526 | * And if we were unable to get a new slab from the partial slab lists then |
| 2527 | * we need to allocate a new slab. This is the slowest path since it involves |
| 2528 | * a call to the page allocator and the setup of a new slab. |
| 2529 | * |
| 2530 | * Version of __slab_alloc to use when we know that interrupts are |
| 2531 | * already disabled (which is the case for bulk allocation). |
| 2532 | */ |
| 2533 | static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, |
| 2534 | unsigned long addr, struct kmem_cache_cpu *c) |
| 2535 | { |
| 2536 | void *freelist; |
| 2537 | struct page *page; |
| 2538 | |
| 2539 | page = c->page; |
| 2540 | if (!page) |
| 2541 | goto new_slab; |
| 2542 | redo: |
| 2543 | |
| 2544 | if (unlikely(!node_match(page, node))) { |
| 2545 | int searchnode = node; |
| 2546 | |
| 2547 | if (node != NUMA_NO_NODE && !node_present_pages(node)) |
| 2548 | searchnode = node_to_mem_node(node); |
| 2549 | |
| 2550 | if (unlikely(!node_match(page, searchnode))) { |
| 2551 | stat(s, ALLOC_NODE_MISMATCH); |
| 2552 | deactivate_slab(s, page, c->freelist, c); |
| 2553 | goto new_slab; |
| 2554 | } |
| 2555 | } |
| 2556 | |
| 2557 | /* |
| 2558 | * By rights, we should be searching for a slab page that was |
| 2559 | * PFMEMALLOC but right now, we are losing the pfmemalloc |
| 2560 | * information when the page leaves the per-cpu allocator |
| 2561 | */ |
| 2562 | if (unlikely(!pfmemalloc_match(page, gfpflags))) { |
| 2563 | deactivate_slab(s, page, c->freelist, c); |
| 2564 | goto new_slab; |
| 2565 | } |
| 2566 | |
| 2567 | /* must check again c->freelist in case of cpu migration or IRQ */ |
| 2568 | freelist = c->freelist; |
| 2569 | if (freelist) |
| 2570 | goto load_freelist; |
| 2571 | |
| 2572 | freelist = get_freelist(s, page); |
| 2573 | |
| 2574 | if (!freelist) { |
| 2575 | c->page = NULL; |
| 2576 | stat(s, DEACTIVATE_BYPASS); |
| 2577 | goto new_slab; |
| 2578 | } |
| 2579 | |
| 2580 | stat(s, ALLOC_REFILL); |
| 2581 | |
| 2582 | load_freelist: |
| 2583 | /* |
| 2584 | * freelist is pointing to the list of objects to be used. |
| 2585 | * page is pointing to the page from which the objects are obtained. |
| 2586 | * That page must be frozen for per cpu allocations to work. |
| 2587 | */ |
| 2588 | VM_BUG_ON(!c->page->frozen); |
| 2589 | c->freelist = get_freepointer(s, freelist); |
| 2590 | c->tid = next_tid(c->tid); |
| 2591 | return freelist; |
| 2592 | |
| 2593 | new_slab: |
| 2594 | |
| 2595 | if (slub_percpu_partial(c)) { |
| 2596 | page = c->page = slub_percpu_partial(c); |
| 2597 | slub_set_percpu_partial(c, page); |
| 2598 | stat(s, CPU_PARTIAL_ALLOC); |
| 2599 | goto redo; |
| 2600 | } |
| 2601 | |
| 2602 | freelist = new_slab_objects(s, gfpflags, node, &c); |
| 2603 | |
| 2604 | if (unlikely(!freelist)) { |
| 2605 | slab_out_of_memory(s, gfpflags, node); |
| 2606 | return NULL; |
| 2607 | } |
| 2608 | |
| 2609 | page = c->page; |
| 2610 | if (likely(!kmem_cache_debug(s) && pfmemalloc_match(page, gfpflags))) |
| 2611 | goto load_freelist; |
| 2612 | |
| 2613 | /* Only entered in the debug case */ |
| 2614 | if (kmem_cache_debug(s) && |
| 2615 | !alloc_debug_processing(s, page, freelist, addr)) |
| 2616 | goto new_slab; /* Slab failed checks. Next slab needed */ |
| 2617 | |
| 2618 | deactivate_slab(s, page, get_freepointer(s, freelist), c); |
| 2619 | return freelist; |
| 2620 | } |
| 2621 | |
| 2622 | /* |
| 2623 | * Another one that disabled interrupt and compensates for possible |
| 2624 | * cpu changes by refetching the per cpu area pointer. |
| 2625 | */ |
| 2626 | static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node, |
| 2627 | unsigned long addr, struct kmem_cache_cpu *c) |
| 2628 | { |
| 2629 | void *p; |
| 2630 | unsigned long flags; |
| 2631 | |
| 2632 | local_irq_save(flags); |
| 2633 | #ifdef CONFIG_PREEMPT |
| 2634 | /* |
| 2635 | * We may have been preempted and rescheduled on a different |
| 2636 | * cpu before disabling interrupts. Need to reload cpu area |
| 2637 | * pointer. |
| 2638 | */ |
| 2639 | c = this_cpu_ptr(s->cpu_slab); |
| 2640 | #endif |
| 2641 | |
| 2642 | p = ___slab_alloc(s, gfpflags, node, addr, c); |
| 2643 | local_irq_restore(flags); |
| 2644 | return p; |
| 2645 | } |
| 2646 | |
| 2647 | /* |
| 2648 | * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc) |
| 2649 | * have the fastpath folded into their functions. So no function call |
| 2650 | * overhead for requests that can be satisfied on the fastpath. |
| 2651 | * |
| 2652 | * The fastpath works by first checking if the lockless freelist can be used. |
| 2653 | * If not then __slab_alloc is called for slow processing. |
| 2654 | * |
| 2655 | * Otherwise we can simply pick the next object from the lockless free list. |
| 2656 | */ |
| 2657 | static __always_inline void *slab_alloc_node(struct kmem_cache *s, |
| 2658 | gfp_t gfpflags, int node, unsigned long addr) |
| 2659 | { |
| 2660 | void *object; |
| 2661 | struct kmem_cache_cpu *c; |
| 2662 | struct page *page; |
| 2663 | unsigned long tid; |
| 2664 | |
| 2665 | s = slab_pre_alloc_hook(s, gfpflags); |
| 2666 | if (!s) |
| 2667 | return NULL; |
| 2668 | redo: |
| 2669 | /* |
| 2670 | * Must read kmem_cache cpu data via this cpu ptr. Preemption is |
| 2671 | * enabled. We may switch back and forth between cpus while |
| 2672 | * reading from one cpu area. That does not matter as long |
| 2673 | * as we end up on the original cpu again when doing the cmpxchg. |
| 2674 | * |
| 2675 | * We should guarantee that tid and kmem_cache are retrieved on |
| 2676 | * the same cpu. It could be different if CONFIG_PREEMPT so we need |
| 2677 | * to check if it is matched or not. |
| 2678 | */ |
| 2679 | do { |
| 2680 | tid = this_cpu_read(s->cpu_slab->tid); |
| 2681 | c = raw_cpu_ptr(s->cpu_slab); |
| 2682 | } while (IS_ENABLED(CONFIG_PREEMPT) && |
| 2683 | unlikely(tid != READ_ONCE(c->tid))); |
| 2684 | |
| 2685 | /* |
| 2686 | * Irqless object alloc/free algorithm used here depends on sequence |
| 2687 | * of fetching cpu_slab's data. tid should be fetched before anything |
| 2688 | * on c to guarantee that object and page associated with previous tid |
| 2689 | * won't be used with current tid. If we fetch tid first, object and |
| 2690 | * page could be one associated with next tid and our alloc/free |
| 2691 | * request will be failed. In this case, we will retry. So, no problem. |
| 2692 | */ |
| 2693 | barrier(); |
| 2694 | |
| 2695 | /* |
| 2696 | * The transaction ids are globally unique per cpu and per operation on |
| 2697 | * a per cpu queue. Thus they can be guarantee that the cmpxchg_double |
| 2698 | * occurs on the right processor and that there was no operation on the |
| 2699 | * linked list in between. |
| 2700 | */ |
| 2701 | |
| 2702 | object = c->freelist; |
| 2703 | page = c->page; |
| 2704 | if (unlikely(!object || !node_match(page, node))) { |
| 2705 | object = __slab_alloc(s, gfpflags, node, addr, c); |
| 2706 | stat(s, ALLOC_SLOWPATH); |
| 2707 | } else { |
| 2708 | void *next_object = get_freepointer_safe(s, object); |
| 2709 | |
| 2710 | /* |
| 2711 | * The cmpxchg will only match if there was no additional |
| 2712 | * operation and if we are on the right processor. |
| 2713 | * |
| 2714 | * The cmpxchg does the following atomically (without lock |
| 2715 | * semantics!) |
| 2716 | * 1. Relocate first pointer to the current per cpu area. |
| 2717 | * 2. Verify that tid and freelist have not been changed |
| 2718 | * 3. If they were not changed replace tid and freelist |
| 2719 | * |
| 2720 | * Since this is without lock semantics the protection is only |
| 2721 | * against code executing on this cpu *not* from access by |
| 2722 | * other cpus. |
| 2723 | */ |
| 2724 | if (unlikely(!this_cpu_cmpxchg_double( |
| 2725 | s->cpu_slab->freelist, s->cpu_slab->tid, |
| 2726 | object, tid, |
| 2727 | next_object, next_tid(tid)))) { |
| 2728 | |
| 2729 | note_cmpxchg_failure("slab_alloc", s, tid); |
| 2730 | goto redo; |
| 2731 | } |
| 2732 | prefetch_freepointer(s, next_object); |
| 2733 | stat(s, ALLOC_FASTPATH); |
| 2734 | } |
| 2735 | |
| 2736 | if (unlikely(gfpflags & __GFP_ZERO) && object) |
| 2737 | memset(object, 0, s->object_size); |
| 2738 | |
| 2739 | slab_post_alloc_hook(s, gfpflags, 1, &object); |
| 2740 | |
| 2741 | return object; |
| 2742 | } |
| 2743 | |
| 2744 | static __always_inline void *slab_alloc(struct kmem_cache *s, |
| 2745 | gfp_t gfpflags, unsigned long addr) |
| 2746 | { |
| 2747 | return slab_alloc_node(s, gfpflags, NUMA_NO_NODE, addr); |
| 2748 | } |
| 2749 | |
| 2750 | void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags) |
| 2751 | { |
| 2752 | void *ret = slab_alloc(s, gfpflags, _RET_IP_); |
| 2753 | |
| 2754 | trace_kmem_cache_alloc(_RET_IP_, ret, s->object_size, |
| 2755 | s->size, gfpflags); |
| 2756 | |
| 2757 | return ret; |
| 2758 | } |
| 2759 | EXPORT_SYMBOL(kmem_cache_alloc); |
| 2760 | |
| 2761 | #ifdef CONFIG_TRACING |
| 2762 | void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size) |
| 2763 | { |
| 2764 | void *ret = slab_alloc(s, gfpflags, _RET_IP_); |
| 2765 | trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags); |
| 2766 | ret = kasan_kmalloc(s, ret, size, gfpflags); |
| 2767 | return ret; |
| 2768 | } |
| 2769 | EXPORT_SYMBOL(kmem_cache_alloc_trace); |
| 2770 | #endif |
| 2771 | |
| 2772 | #ifdef CONFIG_NUMA |
| 2773 | void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node) |
| 2774 | { |
| 2775 | void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_); |
| 2776 | |
| 2777 | trace_kmem_cache_alloc_node(_RET_IP_, ret, |
| 2778 | s->object_size, s->size, gfpflags, node); |
| 2779 | |
| 2780 | return ret; |
| 2781 | } |
| 2782 | EXPORT_SYMBOL(kmem_cache_alloc_node); |
| 2783 | |
| 2784 | #ifdef CONFIG_TRACING |
| 2785 | void *kmem_cache_alloc_node_trace(struct kmem_cache *s, |
| 2786 | gfp_t gfpflags, |
| 2787 | int node, size_t size) |
| 2788 | { |
| 2789 | void *ret = slab_alloc_node(s, gfpflags, node, _RET_IP_); |
| 2790 | |
| 2791 | trace_kmalloc_node(_RET_IP_, ret, |
| 2792 | size, s->size, gfpflags, node); |
| 2793 | |
| 2794 | ret = kasan_kmalloc(s, ret, size, gfpflags); |
| 2795 | return ret; |
| 2796 | } |
| 2797 | EXPORT_SYMBOL(kmem_cache_alloc_node_trace); |
| 2798 | #endif |
| 2799 | #endif |
| 2800 | |
| 2801 | /* |
| 2802 | * Slow path handling. This may still be called frequently since objects |
| 2803 | * have a longer lifetime than the cpu slabs in most processing loads. |
| 2804 | * |
| 2805 | * So we still attempt to reduce cache line usage. Just take the slab |
| 2806 | * lock and free the item. If there is no additional partial page |
| 2807 | * handling required then we can return immediately. |
| 2808 | */ |
| 2809 | static void __slab_free(struct kmem_cache *s, struct page *page, |
| 2810 | void *head, void *tail, int cnt, |
| 2811 | unsigned long addr) |
| 2812 | |
| 2813 | { |
| 2814 | void *prior; |
| 2815 | int was_frozen; |
| 2816 | struct page new; |
| 2817 | unsigned long counters; |
| 2818 | struct kmem_cache_node *n = NULL; |
| 2819 | unsigned long uninitialized_var(flags); |
| 2820 | |
| 2821 | stat(s, FREE_SLOWPATH); |
| 2822 | |
| 2823 | if (kmem_cache_debug(s) && |
| 2824 | !free_debug_processing(s, page, head, tail, cnt, addr)) |
| 2825 | return; |
| 2826 | |
| 2827 | do { |
| 2828 | if (unlikely(n)) { |
| 2829 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 2830 | n = NULL; |
| 2831 | } |
| 2832 | prior = page->freelist; |
| 2833 | counters = page->counters; |
| 2834 | set_freepointer(s, tail, prior); |
| 2835 | new.counters = counters; |
| 2836 | was_frozen = new.frozen; |
| 2837 | new.inuse -= cnt; |
| 2838 | if ((!new.inuse || !prior) && !was_frozen) { |
| 2839 | |
| 2840 | if (kmem_cache_has_cpu_partial(s) && !prior) { |
| 2841 | |
| 2842 | /* |
| 2843 | * Slab was on no list before and will be |
| 2844 | * partially empty |
| 2845 | * We can defer the list move and instead |
| 2846 | * freeze it. |
| 2847 | */ |
| 2848 | new.frozen = 1; |
| 2849 | |
| 2850 | } else { /* Needs to be taken off a list */ |
| 2851 | |
| 2852 | n = get_node(s, page_to_nid(page)); |
| 2853 | /* |
| 2854 | * Speculatively acquire the list_lock. |
| 2855 | * If the cmpxchg does not succeed then we may |
| 2856 | * drop the list_lock without any processing. |
| 2857 | * |
| 2858 | * Otherwise the list_lock will synchronize with |
| 2859 | * other processors updating the list of slabs. |
| 2860 | */ |
| 2861 | spin_lock_irqsave(&n->list_lock, flags); |
| 2862 | |
| 2863 | } |
| 2864 | } |
| 2865 | |
| 2866 | } while (!cmpxchg_double_slab(s, page, |
| 2867 | prior, counters, |
| 2868 | head, new.counters, |
| 2869 | "__slab_free")); |
| 2870 | |
| 2871 | if (likely(!n)) { |
| 2872 | |
| 2873 | /* |
| 2874 | * If we just froze the page then put it onto the |
| 2875 | * per cpu partial list. |
| 2876 | */ |
| 2877 | if (new.frozen && !was_frozen) { |
| 2878 | put_cpu_partial(s, page, 1); |
| 2879 | stat(s, CPU_PARTIAL_FREE); |
| 2880 | } |
| 2881 | /* |
| 2882 | * The list lock was not taken therefore no list |
| 2883 | * activity can be necessary. |
| 2884 | */ |
| 2885 | if (was_frozen) |
| 2886 | stat(s, FREE_FROZEN); |
| 2887 | return; |
| 2888 | } |
| 2889 | |
| 2890 | if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) |
| 2891 | goto slab_empty; |
| 2892 | |
| 2893 | /* |
| 2894 | * Objects left in the slab. If it was not on the partial list before |
| 2895 | * then add it. |
| 2896 | */ |
| 2897 | if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) { |
| 2898 | if (kmem_cache_debug(s)) |
| 2899 | remove_full(s, n, page); |
| 2900 | add_partial(n, page, DEACTIVATE_TO_TAIL); |
| 2901 | stat(s, FREE_ADD_PARTIAL); |
| 2902 | } |
| 2903 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 2904 | return; |
| 2905 | |
| 2906 | slab_empty: |
| 2907 | if (prior) { |
| 2908 | /* |
| 2909 | * Slab on the partial list. |
| 2910 | */ |
| 2911 | remove_partial(n, page); |
| 2912 | stat(s, FREE_REMOVE_PARTIAL); |
| 2913 | } else { |
| 2914 | /* Slab must be on the full list */ |
| 2915 | remove_full(s, n, page); |
| 2916 | } |
| 2917 | |
| 2918 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 2919 | stat(s, FREE_SLAB); |
| 2920 | discard_slab(s, page); |
| 2921 | } |
| 2922 | |
| 2923 | /* |
| 2924 | * Fastpath with forced inlining to produce a kfree and kmem_cache_free that |
| 2925 | * can perform fastpath freeing without additional function calls. |
| 2926 | * |
| 2927 | * The fastpath is only possible if we are freeing to the current cpu slab |
| 2928 | * of this processor. This typically the case if we have just allocated |
| 2929 | * the item before. |
| 2930 | * |
| 2931 | * If fastpath is not possible then fall back to __slab_free where we deal |
| 2932 | * with all sorts of special processing. |
| 2933 | * |
| 2934 | * Bulk free of a freelist with several objects (all pointing to the |
| 2935 | * same page) possible by specifying head and tail ptr, plus objects |
| 2936 | * count (cnt). Bulk free indicated by tail pointer being set. |
| 2937 | */ |
| 2938 | static __always_inline void do_slab_free(struct kmem_cache *s, |
| 2939 | struct page *page, void *head, void *tail, |
| 2940 | int cnt, unsigned long addr) |
| 2941 | { |
| 2942 | void *tail_obj = tail ? : head; |
| 2943 | struct kmem_cache_cpu *c; |
| 2944 | unsigned long tid; |
| 2945 | redo: |
| 2946 | /* |
| 2947 | * Determine the currently cpus per cpu slab. |
| 2948 | * The cpu may change afterward. However that does not matter since |
| 2949 | * data is retrieved via this pointer. If we are on the same cpu |
| 2950 | * during the cmpxchg then the free will succeed. |
| 2951 | */ |
| 2952 | do { |
| 2953 | tid = this_cpu_read(s->cpu_slab->tid); |
| 2954 | c = raw_cpu_ptr(s->cpu_slab); |
| 2955 | } while (IS_ENABLED(CONFIG_PREEMPT) && |
| 2956 | unlikely(tid != READ_ONCE(c->tid))); |
| 2957 | |
| 2958 | /* Same with comment on barrier() in slab_alloc_node() */ |
| 2959 | barrier(); |
| 2960 | |
| 2961 | if (likely(page == c->page)) { |
| 2962 | set_freepointer(s, tail_obj, c->freelist); |
| 2963 | |
| 2964 | if (unlikely(!this_cpu_cmpxchg_double( |
| 2965 | s->cpu_slab->freelist, s->cpu_slab->tid, |
| 2966 | c->freelist, tid, |
| 2967 | head, next_tid(tid)))) { |
| 2968 | |
| 2969 | note_cmpxchg_failure("slab_free", s, tid); |
| 2970 | goto redo; |
| 2971 | } |
| 2972 | stat(s, FREE_FASTPATH); |
| 2973 | } else |
| 2974 | __slab_free(s, page, head, tail_obj, cnt, addr); |
| 2975 | |
| 2976 | } |
| 2977 | |
| 2978 | static __always_inline void slab_free(struct kmem_cache *s, struct page *page, |
| 2979 | void *head, void *tail, int cnt, |
| 2980 | unsigned long addr) |
| 2981 | { |
| 2982 | /* |
| 2983 | * With KASAN enabled slab_free_freelist_hook modifies the freelist |
| 2984 | * to remove objects, whose reuse must be delayed. |
| 2985 | */ |
| 2986 | if (slab_free_freelist_hook(s, &head, &tail)) |
| 2987 | do_slab_free(s, page, head, tail, cnt, addr); |
| 2988 | } |
| 2989 | |
| 2990 | #ifdef CONFIG_KASAN_GENERIC |
| 2991 | void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr) |
| 2992 | { |
| 2993 | do_slab_free(cache, virt_to_head_page(x), x, NULL, 1, addr); |
| 2994 | } |
| 2995 | #endif |
| 2996 | |
| 2997 | void kmem_cache_free(struct kmem_cache *s, void *x) |
| 2998 | { |
| 2999 | s = cache_from_obj(s, x); |
| 3000 | if (!s) |
| 3001 | return; |
| 3002 | slab_free(s, virt_to_head_page(x), x, NULL, 1, _RET_IP_); |
| 3003 | trace_kmem_cache_free(_RET_IP_, x); |
| 3004 | } |
| 3005 | EXPORT_SYMBOL(kmem_cache_free); |
| 3006 | |
| 3007 | struct detached_freelist { |
| 3008 | struct page *page; |
| 3009 | void *tail; |
| 3010 | void *freelist; |
| 3011 | int cnt; |
| 3012 | struct kmem_cache *s; |
| 3013 | }; |
| 3014 | |
| 3015 | /* |
| 3016 | * This function progressively scans the array with free objects (with |
| 3017 | * a limited look ahead) and extract objects belonging to the same |
| 3018 | * page. It builds a detached freelist directly within the given |
| 3019 | * page/objects. This can happen without any need for |
| 3020 | * synchronization, because the objects are owned by running process. |
| 3021 | * The freelist is build up as a single linked list in the objects. |
| 3022 | * The idea is, that this detached freelist can then be bulk |
| 3023 | * transferred to the real freelist(s), but only requiring a single |
| 3024 | * synchronization primitive. Look ahead in the array is limited due |
| 3025 | * to performance reasons. |
| 3026 | */ |
| 3027 | static inline |
| 3028 | int build_detached_freelist(struct kmem_cache *s, size_t size, |
| 3029 | void **p, struct detached_freelist *df) |
| 3030 | { |
| 3031 | size_t first_skipped_index = 0; |
| 3032 | int lookahead = 3; |
| 3033 | void *object; |
| 3034 | struct page *page; |
| 3035 | |
| 3036 | /* Always re-init detached_freelist */ |
| 3037 | df->page = NULL; |
| 3038 | |
| 3039 | do { |
| 3040 | object = p[--size]; |
| 3041 | /* Do we need !ZERO_OR_NULL_PTR(object) here? (for kfree) */ |
| 3042 | } while (!object && size); |
| 3043 | |
| 3044 | if (!object) |
| 3045 | return 0; |
| 3046 | |
| 3047 | page = virt_to_head_page(object); |
| 3048 | if (!s) { |
| 3049 | /* Handle kalloc'ed objects */ |
| 3050 | if (unlikely(!PageSlab(page))) { |
| 3051 | BUG_ON(!PageCompound(page)); |
| 3052 | kfree_hook(object); |
| 3053 | __free_pages(page, compound_order(page)); |
| 3054 | p[size] = NULL; /* mark object processed */ |
| 3055 | return size; |
| 3056 | } |
| 3057 | /* Derive kmem_cache from object */ |
| 3058 | df->s = page->slab_cache; |
| 3059 | } else { |
| 3060 | df->s = cache_from_obj(s, object); /* Support for memcg */ |
| 3061 | } |
| 3062 | |
| 3063 | /* Start new detached freelist */ |
| 3064 | df->page = page; |
| 3065 | set_freepointer(df->s, object, NULL); |
| 3066 | df->tail = object; |
| 3067 | df->freelist = object; |
| 3068 | p[size] = NULL; /* mark object processed */ |
| 3069 | df->cnt = 1; |
| 3070 | |
| 3071 | while (size) { |
| 3072 | object = p[--size]; |
| 3073 | if (!object) |
| 3074 | continue; /* Skip processed objects */ |
| 3075 | |
| 3076 | /* df->page is always set at this point */ |
| 3077 | if (df->page == virt_to_head_page(object)) { |
| 3078 | /* Opportunity build freelist */ |
| 3079 | set_freepointer(df->s, object, df->freelist); |
| 3080 | df->freelist = object; |
| 3081 | df->cnt++; |
| 3082 | p[size] = NULL; /* mark object processed */ |
| 3083 | |
| 3084 | continue; |
| 3085 | } |
| 3086 | |
| 3087 | /* Limit look ahead search */ |
| 3088 | if (!--lookahead) |
| 3089 | break; |
| 3090 | |
| 3091 | if (!first_skipped_index) |
| 3092 | first_skipped_index = size + 1; |
| 3093 | } |
| 3094 | |
| 3095 | return first_skipped_index; |
| 3096 | } |
| 3097 | |
| 3098 | /* Note that interrupts must be enabled when calling this function. */ |
| 3099 | void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p) |
| 3100 | { |
| 3101 | if (WARN_ON(!size)) |
| 3102 | return; |
| 3103 | |
| 3104 | do { |
| 3105 | struct detached_freelist df; |
| 3106 | |
| 3107 | size = build_detached_freelist(s, size, p, &df); |
| 3108 | if (!df.page) |
| 3109 | continue; |
| 3110 | |
| 3111 | slab_free(df.s, df.page, df.freelist, df.tail, df.cnt,_RET_IP_); |
| 3112 | } while (likely(size)); |
| 3113 | } |
| 3114 | EXPORT_SYMBOL(kmem_cache_free_bulk); |
| 3115 | |
| 3116 | /* Note that interrupts must be enabled when calling this function. */ |
| 3117 | int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, |
| 3118 | void **p) |
| 3119 | { |
| 3120 | struct kmem_cache_cpu *c; |
| 3121 | int i; |
| 3122 | |
| 3123 | /* memcg and kmem_cache debug support */ |
| 3124 | s = slab_pre_alloc_hook(s, flags); |
| 3125 | if (unlikely(!s)) |
| 3126 | return false; |
| 3127 | /* |
| 3128 | * Drain objects in the per cpu slab, while disabling local |
| 3129 | * IRQs, which protects against PREEMPT and interrupts |
| 3130 | * handlers invoking normal fastpath. |
| 3131 | */ |
| 3132 | local_irq_disable(); |
| 3133 | c = this_cpu_ptr(s->cpu_slab); |
| 3134 | |
| 3135 | for (i = 0; i < size; i++) { |
| 3136 | void *object = c->freelist; |
| 3137 | |
| 3138 | if (unlikely(!object)) { |
| 3139 | /* |
| 3140 | * Invoking slow path likely have side-effect |
| 3141 | * of re-populating per CPU c->freelist |
| 3142 | */ |
| 3143 | p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE, |
| 3144 | _RET_IP_, c); |
| 3145 | if (unlikely(!p[i])) |
| 3146 | goto error; |
| 3147 | |
| 3148 | c = this_cpu_ptr(s->cpu_slab); |
| 3149 | continue; /* goto for-loop */ |
| 3150 | } |
| 3151 | c->freelist = get_freepointer(s, object); |
| 3152 | p[i] = object; |
| 3153 | } |
| 3154 | c->tid = next_tid(c->tid); |
| 3155 | local_irq_enable(); |
| 3156 | |
| 3157 | /* Clear memory outside IRQ disabled fastpath loop */ |
| 3158 | if (unlikely(flags & __GFP_ZERO)) { |
| 3159 | int j; |
| 3160 | |
| 3161 | for (j = 0; j < i; j++) |
| 3162 | memset(p[j], 0, s->object_size); |
| 3163 | } |
| 3164 | |
| 3165 | /* memcg and kmem_cache debug support */ |
| 3166 | slab_post_alloc_hook(s, flags, size, p); |
| 3167 | return i; |
| 3168 | error: |
| 3169 | local_irq_enable(); |
| 3170 | slab_post_alloc_hook(s, flags, i, p); |
| 3171 | __kmem_cache_free_bulk(s, i, p); |
| 3172 | return 0; |
| 3173 | } |
| 3174 | EXPORT_SYMBOL(kmem_cache_alloc_bulk); |
| 3175 | |
| 3176 | |
| 3177 | /* |
| 3178 | * Object placement in a slab is made very easy because we always start at |
| 3179 | * offset 0. If we tune the size of the object to the alignment then we can |
| 3180 | * get the required alignment by putting one properly sized object after |
| 3181 | * another. |
| 3182 | * |
| 3183 | * Notice that the allocation order determines the sizes of the per cpu |
| 3184 | * caches. Each processor has always one slab available for allocations. |
| 3185 | * Increasing the allocation order reduces the number of times that slabs |
| 3186 | * must be moved on and off the partial lists and is therefore a factor in |
| 3187 | * locking overhead. |
| 3188 | */ |
| 3189 | |
| 3190 | /* |
| 3191 | * Mininum / Maximum order of slab pages. This influences locking overhead |
| 3192 | * and slab fragmentation. A higher order reduces the number of partial slabs |
| 3193 | * and increases the number of allocations possible without having to |
| 3194 | * take the list_lock. |
| 3195 | */ |
| 3196 | static unsigned int slub_min_order; |
| 3197 | static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER; |
| 3198 | static unsigned int slub_min_objects; |
| 3199 | |
| 3200 | /* |
| 3201 | * Calculate the order of allocation given an slab object size. |
| 3202 | * |
| 3203 | * The order of allocation has significant impact on performance and other |
| 3204 | * system components. Generally order 0 allocations should be preferred since |
| 3205 | * order 0 does not cause fragmentation in the page allocator. Larger objects |
| 3206 | * be problematic to put into order 0 slabs because there may be too much |
| 3207 | * unused space left. We go to a higher order if more than 1/16th of the slab |
| 3208 | * would be wasted. |
| 3209 | * |
| 3210 | * In order to reach satisfactory performance we must ensure that a minimum |
| 3211 | * number of objects is in one slab. Otherwise we may generate too much |
| 3212 | * activity on the partial lists which requires taking the list_lock. This is |
| 3213 | * less a concern for large slabs though which are rarely used. |
| 3214 | * |
| 3215 | * slub_max_order specifies the order where we begin to stop considering the |
| 3216 | * number of objects in a slab as critical. If we reach slub_max_order then |
| 3217 | * we try to keep the page order as low as possible. So we accept more waste |
| 3218 | * of space in favor of a small page order. |
| 3219 | * |
| 3220 | * Higher order allocations also allow the placement of more objects in a |
| 3221 | * slab and thereby reduce object handling overhead. If the user has |
| 3222 | * requested a higher mininum order then we start with that one instead of |
| 3223 | * the smallest order which will fit the object. |
| 3224 | */ |
| 3225 | static inline unsigned int slab_order(unsigned int size, |
| 3226 | unsigned int min_objects, unsigned int max_order, |
| 3227 | unsigned int fract_leftover) |
| 3228 | { |
| 3229 | unsigned int min_order = slub_min_order; |
| 3230 | unsigned int order; |
| 3231 | |
| 3232 | if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE) |
| 3233 | return get_order(size * MAX_OBJS_PER_PAGE) - 1; |
| 3234 | |
| 3235 | for (order = max(min_order, (unsigned int)get_order(min_objects * size)); |
| 3236 | order <= max_order; order++) { |
| 3237 | |
| 3238 | unsigned int slab_size = (unsigned int)PAGE_SIZE << order; |
| 3239 | unsigned int rem; |
| 3240 | |
| 3241 | rem = slab_size % size; |
| 3242 | |
| 3243 | if (rem <= slab_size / fract_leftover) |
| 3244 | break; |
| 3245 | } |
| 3246 | |
| 3247 | return order; |
| 3248 | } |
| 3249 | |
| 3250 | static inline int calculate_order(unsigned int size) |
| 3251 | { |
| 3252 | unsigned int order; |
| 3253 | unsigned int min_objects; |
| 3254 | unsigned int max_objects; |
| 3255 | |
| 3256 | /* |
| 3257 | * Attempt to find best configuration for a slab. This |
| 3258 | * works by first attempting to generate a layout with |
| 3259 | * the best configuration and backing off gradually. |
| 3260 | * |
| 3261 | * First we increase the acceptable waste in a slab. Then |
| 3262 | * we reduce the minimum objects required in a slab. |
| 3263 | */ |
| 3264 | min_objects = slub_min_objects; |
| 3265 | if (!min_objects) |
| 3266 | min_objects = 4 * (fls(nr_cpu_ids) + 1); |
| 3267 | max_objects = order_objects(slub_max_order, size); |
| 3268 | min_objects = min(min_objects, max_objects); |
| 3269 | |
| 3270 | while (min_objects > 1) { |
| 3271 | unsigned int fraction; |
| 3272 | |
| 3273 | fraction = 16; |
| 3274 | while (fraction >= 4) { |
| 3275 | order = slab_order(size, min_objects, |
| 3276 | slub_max_order, fraction); |
| 3277 | if (order <= slub_max_order) |
| 3278 | return order; |
| 3279 | fraction /= 2; |
| 3280 | } |
| 3281 | min_objects--; |
| 3282 | } |
| 3283 | |
| 3284 | /* |
| 3285 | * We were unable to place multiple objects in a slab. Now |
| 3286 | * lets see if we can place a single object there. |
| 3287 | */ |
| 3288 | order = slab_order(size, 1, slub_max_order, 1); |
| 3289 | if (order <= slub_max_order) |
| 3290 | return order; |
| 3291 | |
| 3292 | /* |
| 3293 | * Doh this slab cannot be placed using slub_max_order. |
| 3294 | */ |
| 3295 | order = slab_order(size, 1, MAX_ORDER, 1); |
| 3296 | if (order < MAX_ORDER) |
| 3297 | return order; |
| 3298 | return -ENOSYS; |
| 3299 | } |
| 3300 | |
| 3301 | static void |
| 3302 | init_kmem_cache_node(struct kmem_cache_node *n) |
| 3303 | { |
| 3304 | n->nr_partial = 0; |
| 3305 | spin_lock_init(&n->list_lock); |
| 3306 | INIT_LIST_HEAD(&n->partial); |
| 3307 | #ifdef CONFIG_SLUB_DEBUG |
| 3308 | atomic_long_set(&n->nr_slabs, 0); |
| 3309 | atomic_long_set(&n->total_objects, 0); |
| 3310 | INIT_LIST_HEAD(&n->full); |
| 3311 | #endif |
| 3312 | } |
| 3313 | |
| 3314 | static inline int alloc_kmem_cache_cpus(struct kmem_cache *s) |
| 3315 | { |
| 3316 | BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE < |
| 3317 | KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu)); |
| 3318 | |
| 3319 | /* |
| 3320 | * Must align to double word boundary for the double cmpxchg |
| 3321 | * instructions to work; see __pcpu_double_call_return_bool(). |
| 3322 | */ |
| 3323 | s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu), |
| 3324 | 2 * sizeof(void *)); |
| 3325 | |
| 3326 | if (!s->cpu_slab) |
| 3327 | return 0; |
| 3328 | |
| 3329 | init_kmem_cache_cpus(s); |
| 3330 | |
| 3331 | return 1; |
| 3332 | } |
| 3333 | |
| 3334 | static struct kmem_cache *kmem_cache_node; |
| 3335 | |
| 3336 | /* |
| 3337 | * No kmalloc_node yet so do it by hand. We know that this is the first |
| 3338 | * slab on the node for this slabcache. There are no concurrent accesses |
| 3339 | * possible. |
| 3340 | * |
| 3341 | * Note that this function only works on the kmem_cache_node |
| 3342 | * when allocating for the kmem_cache_node. This is used for bootstrapping |
| 3343 | * memory on a fresh node that has no slab structures yet. |
| 3344 | */ |
| 3345 | static void early_kmem_cache_node_alloc(int node) |
| 3346 | { |
| 3347 | struct page *page; |
| 3348 | struct kmem_cache_node *n; |
| 3349 | |
| 3350 | BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node)); |
| 3351 | |
| 3352 | page = new_slab(kmem_cache_node, GFP_NOWAIT, node); |
| 3353 | |
| 3354 | BUG_ON(!page); |
| 3355 | if (page_to_nid(page) != node) { |
| 3356 | pr_err("SLUB: Unable to allocate memory from node %d\n", node); |
| 3357 | pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n"); |
| 3358 | } |
| 3359 | |
| 3360 | n = page->freelist; |
| 3361 | BUG_ON(!n); |
| 3362 | #ifdef CONFIG_SLUB_DEBUG |
| 3363 | init_object(kmem_cache_node, n, SLUB_RED_ACTIVE); |
| 3364 | init_tracking(kmem_cache_node, n); |
| 3365 | #endif |
| 3366 | n = kasan_kmalloc(kmem_cache_node, n, sizeof(struct kmem_cache_node), |
| 3367 | GFP_KERNEL); |
| 3368 | page->freelist = get_freepointer(kmem_cache_node, n); |
| 3369 | page->inuse = 1; |
| 3370 | page->frozen = 0; |
| 3371 | kmem_cache_node->node[node] = n; |
| 3372 | init_kmem_cache_node(n); |
| 3373 | inc_slabs_node(kmem_cache_node, node, page->objects); |
| 3374 | |
| 3375 | /* |
| 3376 | * No locks need to be taken here as it has just been |
| 3377 | * initialized and there is no concurrent access. |
| 3378 | */ |
| 3379 | __add_partial(n, page, DEACTIVATE_TO_HEAD); |
| 3380 | } |
| 3381 | |
| 3382 | static void free_kmem_cache_nodes(struct kmem_cache *s) |
| 3383 | { |
| 3384 | int node; |
| 3385 | struct kmem_cache_node *n; |
| 3386 | |
| 3387 | for_each_kmem_cache_node(s, node, n) { |
| 3388 | s->node[node] = NULL; |
| 3389 | kmem_cache_free(kmem_cache_node, n); |
| 3390 | } |
| 3391 | } |
| 3392 | |
| 3393 | void __kmem_cache_release(struct kmem_cache *s) |
| 3394 | { |
| 3395 | cache_random_seq_destroy(s); |
| 3396 | free_percpu(s->cpu_slab); |
| 3397 | free_kmem_cache_nodes(s); |
| 3398 | } |
| 3399 | |
| 3400 | static int init_kmem_cache_nodes(struct kmem_cache *s) |
| 3401 | { |
| 3402 | int node; |
| 3403 | |
| 3404 | for_each_node_state(node, N_NORMAL_MEMORY) { |
| 3405 | struct kmem_cache_node *n; |
| 3406 | |
| 3407 | if (slab_state == DOWN) { |
| 3408 | early_kmem_cache_node_alloc(node); |
| 3409 | continue; |
| 3410 | } |
| 3411 | n = kmem_cache_alloc_node(kmem_cache_node, |
| 3412 | GFP_KERNEL, node); |
| 3413 | |
| 3414 | if (!n) { |
| 3415 | free_kmem_cache_nodes(s); |
| 3416 | return 0; |
| 3417 | } |
| 3418 | |
| 3419 | init_kmem_cache_node(n); |
| 3420 | s->node[node] = n; |
| 3421 | } |
| 3422 | return 1; |
| 3423 | } |
| 3424 | |
| 3425 | static void set_min_partial(struct kmem_cache *s, unsigned long min) |
| 3426 | { |
| 3427 | if (min < MIN_PARTIAL) |
| 3428 | min = MIN_PARTIAL; |
| 3429 | else if (min > MAX_PARTIAL) |
| 3430 | min = MAX_PARTIAL; |
| 3431 | s->min_partial = min; |
| 3432 | } |
| 3433 | |
| 3434 | static void set_cpu_partial(struct kmem_cache *s) |
| 3435 | { |
| 3436 | #ifdef CONFIG_SLUB_CPU_PARTIAL |
| 3437 | /* |
| 3438 | * cpu_partial determined the maximum number of objects kept in the |
| 3439 | * per cpu partial lists of a processor. |
| 3440 | * |
| 3441 | * Per cpu partial lists mainly contain slabs that just have one |
| 3442 | * object freed. If they are used for allocation then they can be |
| 3443 | * filled up again with minimal effort. The slab will never hit the |
| 3444 | * per node partial lists and therefore no locking will be required. |
| 3445 | * |
| 3446 | * This setting also determines |
| 3447 | * |
| 3448 | * A) The number of objects from per cpu partial slabs dumped to the |
| 3449 | * per node list when we reach the limit. |
| 3450 | * B) The number of objects in cpu partial slabs to extract from the |
| 3451 | * per node list when we run out of per cpu objects. We only fetch |
| 3452 | * 50% to keep some capacity around for frees. |
| 3453 | */ |
| 3454 | if (!kmem_cache_has_cpu_partial(s)) |
| 3455 | s->cpu_partial = 0; |
| 3456 | else if (s->size >= PAGE_SIZE) |
| 3457 | s->cpu_partial = 2; |
| 3458 | else if (s->size >= 1024) |
| 3459 | s->cpu_partial = 6; |
| 3460 | else if (s->size >= 256) |
| 3461 | s->cpu_partial = 13; |
| 3462 | else |
| 3463 | s->cpu_partial = 30; |
| 3464 | #endif |
| 3465 | } |
| 3466 | |
| 3467 | /* |
| 3468 | * calculate_sizes() determines the order and the distribution of data within |
| 3469 | * a slab object. |
| 3470 | */ |
| 3471 | static int calculate_sizes(struct kmem_cache *s, int forced_order) |
| 3472 | { |
| 3473 | slab_flags_t flags = s->flags; |
| 3474 | unsigned int size = s->object_size; |
| 3475 | unsigned int order; |
| 3476 | |
| 3477 | /* |
| 3478 | * Round up object size to the next word boundary. We can only |
| 3479 | * place the free pointer at word boundaries and this determines |
| 3480 | * the possible location of the free pointer. |
| 3481 | */ |
| 3482 | size = ALIGN(size, sizeof(void *)); |
| 3483 | |
| 3484 | #ifdef CONFIG_SLUB_DEBUG |
| 3485 | /* |
| 3486 | * Determine if we can poison the object itself. If the user of |
| 3487 | * the slab may touch the object after free or before allocation |
| 3488 | * then we should never poison the object itself. |
| 3489 | */ |
| 3490 | if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) && |
| 3491 | !s->ctor) |
| 3492 | s->flags |= __OBJECT_POISON; |
| 3493 | else |
| 3494 | s->flags &= ~__OBJECT_POISON; |
| 3495 | |
| 3496 | |
| 3497 | /* |
| 3498 | * If we are Redzoning then check if there is some space between the |
| 3499 | * end of the object and the free pointer. If not then add an |
| 3500 | * additional word to have some bytes to store Redzone information. |
| 3501 | */ |
| 3502 | if ((flags & SLAB_RED_ZONE) && size == s->object_size) |
| 3503 | size += sizeof(void *); |
| 3504 | #endif |
| 3505 | |
| 3506 | /* |
| 3507 | * With that we have determined the number of bytes in actual use |
| 3508 | * by the object. This is the potential offset to the free pointer. |
| 3509 | */ |
| 3510 | s->inuse = size; |
| 3511 | |
| 3512 | if (((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) || |
| 3513 | s->ctor)) { |
| 3514 | /* |
| 3515 | * Relocate free pointer after the object if it is not |
| 3516 | * permitted to overwrite the first word of the object on |
| 3517 | * kmem_cache_free. |
| 3518 | * |
| 3519 | * This is the case if we do RCU, have a constructor or |
| 3520 | * destructor or are poisoning the objects. |
| 3521 | */ |
| 3522 | s->offset = size; |
| 3523 | size += sizeof(void *); |
| 3524 | } |
| 3525 | |
| 3526 | #ifdef CONFIG_SLUB_DEBUG |
| 3527 | if (flags & SLAB_STORE_USER) |
| 3528 | /* |
| 3529 | * Need to store information about allocs and frees after |
| 3530 | * the object. |
| 3531 | */ |
| 3532 | size += 2 * sizeof(struct track); |
| 3533 | #endif |
| 3534 | |
| 3535 | kasan_cache_create(s, &size, &s->flags); |
| 3536 | #ifdef CONFIG_SLUB_DEBUG |
| 3537 | if (flags & SLAB_RED_ZONE) { |
| 3538 | /* |
| 3539 | * Add some empty padding so that we can catch |
| 3540 | * overwrites from earlier objects rather than let |
| 3541 | * tracking information or the free pointer be |
| 3542 | * corrupted if a user writes before the start |
| 3543 | * of the object. |
| 3544 | */ |
| 3545 | size += sizeof(void *); |
| 3546 | |
| 3547 | s->red_left_pad = sizeof(void *); |
| 3548 | s->red_left_pad = ALIGN(s->red_left_pad, s->align); |
| 3549 | size += s->red_left_pad; |
| 3550 | } |
| 3551 | #endif |
| 3552 | |
| 3553 | /* |
| 3554 | * SLUB stores one object immediately after another beginning from |
| 3555 | * offset 0. In order to align the objects we have to simply size |
| 3556 | * each object to conform to the alignment. |
| 3557 | */ |
| 3558 | size = ALIGN(size, s->align); |
| 3559 | s->size = size; |
| 3560 | if (forced_order >= 0) |
| 3561 | order = forced_order; |
| 3562 | else |
| 3563 | order = calculate_order(size); |
| 3564 | |
| 3565 | if ((int)order < 0) |
| 3566 | return 0; |
| 3567 | |
| 3568 | s->allocflags = 0; |
| 3569 | if (order) |
| 3570 | s->allocflags |= __GFP_COMP; |
| 3571 | |
| 3572 | if (s->flags & SLAB_CACHE_DMA) |
| 3573 | s->allocflags |= GFP_DMA; |
| 3574 | |
| 3575 | if (s->flags & SLAB_RECLAIM_ACCOUNT) |
| 3576 | s->allocflags |= __GFP_RECLAIMABLE; |
| 3577 | |
| 3578 | /* |
| 3579 | * Determine the number of objects per slab |
| 3580 | */ |
| 3581 | s->oo = oo_make(order, size); |
| 3582 | s->min = oo_make(get_order(size), size); |
| 3583 | if (oo_objects(s->oo) > oo_objects(s->max)) |
| 3584 | s->max = s->oo; |
| 3585 | |
| 3586 | return !!oo_objects(s->oo); |
| 3587 | } |
| 3588 | |
| 3589 | static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags) |
| 3590 | { |
| 3591 | s->flags = kmem_cache_flags(s->size, flags, s->name, s->ctor); |
| 3592 | #ifdef CONFIG_SLAB_FREELIST_HARDENED |
| 3593 | s->random = get_random_long(); |
| 3594 | #endif |
| 3595 | |
| 3596 | if (!calculate_sizes(s, -1)) |
| 3597 | goto error; |
| 3598 | if (disable_higher_order_debug) { |
| 3599 | /* |
| 3600 | * Disable debugging flags that store metadata if the min slab |
| 3601 | * order increased. |
| 3602 | */ |
| 3603 | if (get_order(s->size) > get_order(s->object_size)) { |
| 3604 | s->flags &= ~DEBUG_METADATA_FLAGS; |
| 3605 | s->offset = 0; |
| 3606 | if (!calculate_sizes(s, -1)) |
| 3607 | goto error; |
| 3608 | } |
| 3609 | } |
| 3610 | |
| 3611 | #if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \ |
| 3612 | defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) |
| 3613 | if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0) |
| 3614 | /* Enable fast mode */ |
| 3615 | s->flags |= __CMPXCHG_DOUBLE; |
| 3616 | #endif |
| 3617 | |
| 3618 | /* |
| 3619 | * The larger the object size is, the more pages we want on the partial |
| 3620 | * list to avoid pounding the page allocator excessively. |
| 3621 | */ |
| 3622 | set_min_partial(s, ilog2(s->size) / 2); |
| 3623 | |
| 3624 | set_cpu_partial(s); |
| 3625 | |
| 3626 | #ifdef CONFIG_NUMA |
| 3627 | s->remote_node_defrag_ratio = 1000; |
| 3628 | #endif |
| 3629 | |
| 3630 | /* Initialize the pre-computed randomized freelist if slab is up */ |
| 3631 | if (slab_state >= UP) { |
| 3632 | if (init_cache_random_seq(s)) |
| 3633 | goto error; |
| 3634 | } |
| 3635 | |
| 3636 | if (!init_kmem_cache_nodes(s)) |
| 3637 | goto error; |
| 3638 | |
| 3639 | if (alloc_kmem_cache_cpus(s)) |
| 3640 | return 0; |
| 3641 | |
| 3642 | free_kmem_cache_nodes(s); |
| 3643 | error: |
| 3644 | if (flags & SLAB_PANIC) |
| 3645 | panic("Cannot create slab %s size=%u realsize=%u order=%u offset=%u flags=%lx\n", |
| 3646 | s->name, s->size, s->size, |
| 3647 | oo_order(s->oo), s->offset, (unsigned long)flags); |
| 3648 | return -EINVAL; |
| 3649 | } |
| 3650 | |
| 3651 | static void list_slab_objects(struct kmem_cache *s, struct page *page, |
| 3652 | const char *text) |
| 3653 | { |
| 3654 | #ifdef CONFIG_SLUB_DEBUG |
| 3655 | void *addr = page_address(page); |
| 3656 | void *p; |
| 3657 | unsigned long *map = bitmap_zalloc(page->objects, GFP_ATOMIC); |
| 3658 | if (!map) |
| 3659 | return; |
| 3660 | slab_err(s, page, text, s->name); |
| 3661 | slab_lock(page); |
| 3662 | |
| 3663 | get_map(s, page, map); |
| 3664 | for_each_object(p, s, addr, page->objects) { |
| 3665 | |
| 3666 | if (!test_bit(slab_index(p, s, addr), map)) { |
| 3667 | pr_err("INFO: Object 0x%p @offset=%tu\n", p, p - addr); |
| 3668 | print_tracking(s, p); |
| 3669 | } |
| 3670 | } |
| 3671 | slab_unlock(page); |
| 3672 | bitmap_free(map); |
| 3673 | #endif |
| 3674 | } |
| 3675 | |
| 3676 | /* |
| 3677 | * Attempt to free all partial slabs on a node. |
| 3678 | * This is called from __kmem_cache_shutdown(). We must take list_lock |
| 3679 | * because sysfs file might still access partial list after the shutdowning. |
| 3680 | */ |
| 3681 | static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n) |
| 3682 | { |
| 3683 | LIST_HEAD(discard); |
| 3684 | struct page *page, *h; |
| 3685 | |
| 3686 | BUG_ON(irqs_disabled()); |
| 3687 | spin_lock_irq(&n->list_lock); |
| 3688 | list_for_each_entry_safe(page, h, &n->partial, lru) { |
| 3689 | if (!page->inuse) { |
| 3690 | remove_partial(n, page); |
| 3691 | list_add(&page->lru, &discard); |
| 3692 | } else { |
| 3693 | list_slab_objects(s, page, |
| 3694 | "Objects remaining in %s on __kmem_cache_shutdown()"); |
| 3695 | } |
| 3696 | } |
| 3697 | spin_unlock_irq(&n->list_lock); |
| 3698 | |
| 3699 | list_for_each_entry_safe(page, h, &discard, lru) |
| 3700 | discard_slab(s, page); |
| 3701 | } |
| 3702 | |
| 3703 | bool __kmem_cache_empty(struct kmem_cache *s) |
| 3704 | { |
| 3705 | int node; |
| 3706 | struct kmem_cache_node *n; |
| 3707 | |
| 3708 | for_each_kmem_cache_node(s, node, n) |
| 3709 | if (n->nr_partial || slabs_node(s, node)) |
| 3710 | return false; |
| 3711 | return true; |
| 3712 | } |
| 3713 | |
| 3714 | /* |
| 3715 | * Release all resources used by a slab cache. |
| 3716 | */ |
| 3717 | int __kmem_cache_shutdown(struct kmem_cache *s) |
| 3718 | { |
| 3719 | int node; |
| 3720 | struct kmem_cache_node *n; |
| 3721 | |
| 3722 | flush_all(s); |
| 3723 | /* Attempt to free all objects */ |
| 3724 | for_each_kmem_cache_node(s, node, n) { |
| 3725 | free_partial(s, n); |
| 3726 | if (n->nr_partial || slabs_node(s, node)) |
| 3727 | return 1; |
| 3728 | } |
| 3729 | sysfs_slab_remove(s); |
| 3730 | return 0; |
| 3731 | } |
| 3732 | |
| 3733 | /******************************************************************** |
| 3734 | * Kmalloc subsystem |
| 3735 | *******************************************************************/ |
| 3736 | |
| 3737 | static int __init setup_slub_min_order(char *str) |
| 3738 | { |
| 3739 | get_option(&str, (int *)&slub_min_order); |
| 3740 | |
| 3741 | return 1; |
| 3742 | } |
| 3743 | |
| 3744 | __setup("slub_min_order=", setup_slub_min_order); |
| 3745 | |
| 3746 | static int __init setup_slub_max_order(char *str) |
| 3747 | { |
| 3748 | get_option(&str, (int *)&slub_max_order); |
| 3749 | slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1); |
| 3750 | |
| 3751 | return 1; |
| 3752 | } |
| 3753 | |
| 3754 | __setup("slub_max_order=", setup_slub_max_order); |
| 3755 | |
| 3756 | static int __init setup_slub_min_objects(char *str) |
| 3757 | { |
| 3758 | get_option(&str, (int *)&slub_min_objects); |
| 3759 | |
| 3760 | return 1; |
| 3761 | } |
| 3762 | |
| 3763 | __setup("slub_min_objects=", setup_slub_min_objects); |
| 3764 | |
| 3765 | void *__kmalloc(size_t size, gfp_t flags) |
| 3766 | { |
| 3767 | struct kmem_cache *s; |
| 3768 | void *ret; |
| 3769 | |
| 3770 | if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) |
| 3771 | return kmalloc_large(size, flags); |
| 3772 | |
| 3773 | s = kmalloc_slab(size, flags); |
| 3774 | |
| 3775 | if (unlikely(ZERO_OR_NULL_PTR(s))) |
| 3776 | return s; |
| 3777 | |
| 3778 | ret = slab_alloc(s, flags, _RET_IP_); |
| 3779 | |
| 3780 | trace_kmalloc(_RET_IP_, ret, size, s->size, flags); |
| 3781 | |
| 3782 | ret = kasan_kmalloc(s, ret, size, flags); |
| 3783 | |
| 3784 | return ret; |
| 3785 | } |
| 3786 | EXPORT_SYMBOL(__kmalloc); |
| 3787 | |
| 3788 | #ifdef CONFIG_NUMA |
| 3789 | static void *kmalloc_large_node(size_t size, gfp_t flags, int node) |
| 3790 | { |
| 3791 | struct page *page; |
| 3792 | void *ptr = NULL; |
| 3793 | |
| 3794 | flags |= __GFP_COMP; |
| 3795 | page = alloc_pages_node(node, flags, get_order(size)); |
| 3796 | if (page) |
| 3797 | ptr = page_address(page); |
| 3798 | |
| 3799 | return kmalloc_large_node_hook(ptr, size, flags); |
| 3800 | } |
| 3801 | |
| 3802 | void *__kmalloc_node(size_t size, gfp_t flags, int node) |
| 3803 | { |
| 3804 | struct kmem_cache *s; |
| 3805 | void *ret; |
| 3806 | |
| 3807 | if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) { |
| 3808 | ret = kmalloc_large_node(size, flags, node); |
| 3809 | |
| 3810 | trace_kmalloc_node(_RET_IP_, ret, |
| 3811 | size, PAGE_SIZE << get_order(size), |
| 3812 | flags, node); |
| 3813 | |
| 3814 | return ret; |
| 3815 | } |
| 3816 | |
| 3817 | s = kmalloc_slab(size, flags); |
| 3818 | |
| 3819 | if (unlikely(ZERO_OR_NULL_PTR(s))) |
| 3820 | return s; |
| 3821 | |
| 3822 | ret = slab_alloc_node(s, flags, node, _RET_IP_); |
| 3823 | |
| 3824 | trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node); |
| 3825 | |
| 3826 | ret = kasan_kmalloc(s, ret, size, flags); |
| 3827 | |
| 3828 | return ret; |
| 3829 | } |
| 3830 | EXPORT_SYMBOL(__kmalloc_node); |
| 3831 | #endif |
| 3832 | |
| 3833 | #ifdef CONFIG_HARDENED_USERCOPY |
| 3834 | /* |
| 3835 | * Rejects incorrectly sized objects and objects that are to be copied |
| 3836 | * to/from userspace but do not fall entirely within the containing slab |
| 3837 | * cache's usercopy region. |
| 3838 | * |
| 3839 | * Returns NULL if check passes, otherwise const char * to name of cache |
| 3840 | * to indicate an error. |
| 3841 | */ |
| 3842 | void __check_heap_object(const void *ptr, unsigned long n, struct page *page, |
| 3843 | bool to_user) |
| 3844 | { |
| 3845 | struct kmem_cache *s; |
| 3846 | unsigned int offset; |
| 3847 | size_t object_size; |
| 3848 | |
| 3849 | ptr = kasan_reset_tag(ptr); |
| 3850 | |
| 3851 | /* Find object and usable object size. */ |
| 3852 | s = page->slab_cache; |
| 3853 | |
| 3854 | /* Reject impossible pointers. */ |
| 3855 | if (ptr < page_address(page)) |
| 3856 | usercopy_abort("SLUB object not in SLUB page?!", NULL, |
| 3857 | to_user, 0, n); |
| 3858 | |
| 3859 | /* Find offset within object. */ |
| 3860 | offset = (ptr - page_address(page)) % s->size; |
| 3861 | |
| 3862 | /* Adjust for redzone and reject if within the redzone. */ |
| 3863 | if (kmem_cache_debug(s) && s->flags & SLAB_RED_ZONE) { |
| 3864 | if (offset < s->red_left_pad) |
| 3865 | usercopy_abort("SLUB object in left red zone", |
| 3866 | s->name, to_user, offset, n); |
| 3867 | offset -= s->red_left_pad; |
| 3868 | } |
| 3869 | |
| 3870 | /* Allow address range falling entirely within usercopy region. */ |
| 3871 | if (offset >= s->useroffset && |
| 3872 | offset - s->useroffset <= s->usersize && |
| 3873 | n <= s->useroffset - offset + s->usersize) |
| 3874 | return; |
| 3875 | |
| 3876 | /* |
| 3877 | * If the copy is still within the allocated object, produce |
| 3878 | * a warning instead of rejecting the copy. This is intended |
| 3879 | * to be a temporary method to find any missing usercopy |
| 3880 | * whitelists. |
| 3881 | */ |
| 3882 | object_size = slab_ksize(s); |
| 3883 | if (usercopy_fallback && |
| 3884 | offset <= object_size && n <= object_size - offset) { |
| 3885 | usercopy_warn("SLUB object", s->name, to_user, offset, n); |
| 3886 | return; |
| 3887 | } |
| 3888 | |
| 3889 | usercopy_abort("SLUB object", s->name, to_user, offset, n); |
| 3890 | } |
| 3891 | #endif /* CONFIG_HARDENED_USERCOPY */ |
| 3892 | |
| 3893 | static size_t __ksize(const void *object) |
| 3894 | { |
| 3895 | struct page *page; |
| 3896 | |
| 3897 | if (unlikely(object == ZERO_SIZE_PTR)) |
| 3898 | return 0; |
| 3899 | |
| 3900 | page = virt_to_head_page(object); |
| 3901 | |
| 3902 | if (unlikely(!PageSlab(page))) { |
| 3903 | WARN_ON(!PageCompound(page)); |
| 3904 | return PAGE_SIZE << compound_order(page); |
| 3905 | } |
| 3906 | |
| 3907 | return slab_ksize(page->slab_cache); |
| 3908 | } |
| 3909 | |
| 3910 | size_t ksize(const void *object) |
| 3911 | { |
| 3912 | size_t size = __ksize(object); |
| 3913 | /* We assume that ksize callers could use whole allocated area, |
| 3914 | * so we need to unpoison this area. |
| 3915 | */ |
| 3916 | kasan_unpoison_shadow(object, size); |
| 3917 | return size; |
| 3918 | } |
| 3919 | EXPORT_SYMBOL(ksize); |
| 3920 | |
| 3921 | void kfree(const void *x) |
| 3922 | { |
| 3923 | struct page *page; |
| 3924 | void *object = (void *)x; |
| 3925 | |
| 3926 | trace_kfree(_RET_IP_, x); |
| 3927 | |
| 3928 | if (unlikely(ZERO_OR_NULL_PTR(x))) |
| 3929 | return; |
| 3930 | |
| 3931 | page = virt_to_head_page(x); |
| 3932 | if (unlikely(!PageSlab(page))) { |
| 3933 | BUG_ON(!PageCompound(page)); |
| 3934 | kfree_hook(object); |
| 3935 | __free_pages(page, compound_order(page)); |
| 3936 | return; |
| 3937 | } |
| 3938 | slab_free(page->slab_cache, page, object, NULL, 1, _RET_IP_); |
| 3939 | } |
| 3940 | EXPORT_SYMBOL(kfree); |
| 3941 | |
| 3942 | #define SHRINK_PROMOTE_MAX 32 |
| 3943 | |
| 3944 | /* |
| 3945 | * kmem_cache_shrink discards empty slabs and promotes the slabs filled |
| 3946 | * up most to the head of the partial lists. New allocations will then |
| 3947 | * fill those up and thus they can be removed from the partial lists. |
| 3948 | * |
| 3949 | * The slabs with the least items are placed last. This results in them |
| 3950 | * being allocated from last increasing the chance that the last objects |
| 3951 | * are freed in them. |
| 3952 | */ |
| 3953 | int __kmem_cache_shrink(struct kmem_cache *s) |
| 3954 | { |
| 3955 | int node; |
| 3956 | int i; |
| 3957 | struct kmem_cache_node *n; |
| 3958 | struct page *page; |
| 3959 | struct page *t; |
| 3960 | struct list_head discard; |
| 3961 | struct list_head promote[SHRINK_PROMOTE_MAX]; |
| 3962 | unsigned long flags; |
| 3963 | int ret = 0; |
| 3964 | |
| 3965 | flush_all(s); |
| 3966 | for_each_kmem_cache_node(s, node, n) { |
| 3967 | INIT_LIST_HEAD(&discard); |
| 3968 | for (i = 0; i < SHRINK_PROMOTE_MAX; i++) |
| 3969 | INIT_LIST_HEAD(promote + i); |
| 3970 | |
| 3971 | spin_lock_irqsave(&n->list_lock, flags); |
| 3972 | |
| 3973 | /* |
| 3974 | * Build lists of slabs to discard or promote. |
| 3975 | * |
| 3976 | * Note that concurrent frees may occur while we hold the |
| 3977 | * list_lock. page->inuse here is the upper limit. |
| 3978 | */ |
| 3979 | list_for_each_entry_safe(page, t, &n->partial, lru) { |
| 3980 | int free = page->objects - page->inuse; |
| 3981 | |
| 3982 | /* Do not reread page->inuse */ |
| 3983 | barrier(); |
| 3984 | |
| 3985 | /* We do not keep full slabs on the list */ |
| 3986 | BUG_ON(free <= 0); |
| 3987 | |
| 3988 | if (free == page->objects) { |
| 3989 | list_move(&page->lru, &discard); |
| 3990 | n->nr_partial--; |
| 3991 | } else if (free <= SHRINK_PROMOTE_MAX) |
| 3992 | list_move(&page->lru, promote + free - 1); |
| 3993 | } |
| 3994 | |
| 3995 | /* |
| 3996 | * Promote the slabs filled up most to the head of the |
| 3997 | * partial list. |
| 3998 | */ |
| 3999 | for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--) |
| 4000 | list_splice(promote + i, &n->partial); |
| 4001 | |
| 4002 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 4003 | |
| 4004 | /* Release empty slabs */ |
| 4005 | list_for_each_entry_safe(page, t, &discard, lru) |
| 4006 | discard_slab(s, page); |
| 4007 | |
| 4008 | if (slabs_node(s, node)) |
| 4009 | ret = 1; |
| 4010 | } |
| 4011 | |
| 4012 | return ret; |
| 4013 | } |
| 4014 | |
| 4015 | #ifdef CONFIG_MEMCG |
| 4016 | static void kmemcg_cache_deact_after_rcu(struct kmem_cache *s) |
| 4017 | { |
| 4018 | /* |
| 4019 | * Called with all the locks held after a sched RCU grace period. |
| 4020 | * Even if @s becomes empty after shrinking, we can't know that @s |
| 4021 | * doesn't have allocations already in-flight and thus can't |
| 4022 | * destroy @s until the associated memcg is released. |
| 4023 | * |
| 4024 | * However, let's remove the sysfs files for empty caches here. |
| 4025 | * Each cache has a lot of interface files which aren't |
| 4026 | * particularly useful for empty draining caches; otherwise, we can |
| 4027 | * easily end up with millions of unnecessary sysfs files on |
| 4028 | * systems which have a lot of memory and transient cgroups. |
| 4029 | */ |
| 4030 | if (!__kmem_cache_shrink(s)) |
| 4031 | sysfs_slab_remove(s); |
| 4032 | } |
| 4033 | |
| 4034 | void __kmemcg_cache_deactivate(struct kmem_cache *s) |
| 4035 | { |
| 4036 | /* |
| 4037 | * Disable empty slabs caching. Used to avoid pinning offline |
| 4038 | * memory cgroups by kmem pages that can be freed. |
| 4039 | */ |
| 4040 | slub_set_cpu_partial(s, 0); |
| 4041 | s->min_partial = 0; |
| 4042 | |
| 4043 | /* |
| 4044 | * s->cpu_partial is checked locklessly (see put_cpu_partial), so |
| 4045 | * we have to make sure the change is visible before shrinking. |
| 4046 | */ |
| 4047 | slab_deactivate_memcg_cache_rcu_sched(s, kmemcg_cache_deact_after_rcu); |
| 4048 | } |
| 4049 | #endif |
| 4050 | |
| 4051 | static int slab_mem_going_offline_callback(void *arg) |
| 4052 | { |
| 4053 | struct kmem_cache *s; |
| 4054 | |
| 4055 | mutex_lock(&slab_mutex); |
| 4056 | list_for_each_entry(s, &slab_caches, list) |
| 4057 | __kmem_cache_shrink(s); |
| 4058 | mutex_unlock(&slab_mutex); |
| 4059 | |
| 4060 | return 0; |
| 4061 | } |
| 4062 | |
| 4063 | static void slab_mem_offline_callback(void *arg) |
| 4064 | { |
| 4065 | struct kmem_cache_node *n; |
| 4066 | struct kmem_cache *s; |
| 4067 | struct memory_notify *marg = arg; |
| 4068 | int offline_node; |
| 4069 | |
| 4070 | offline_node = marg->status_change_nid_normal; |
| 4071 | |
| 4072 | /* |
| 4073 | * If the node still has available memory. we need kmem_cache_node |
| 4074 | * for it yet. |
| 4075 | */ |
| 4076 | if (offline_node < 0) |
| 4077 | return; |
| 4078 | |
| 4079 | mutex_lock(&slab_mutex); |
| 4080 | list_for_each_entry(s, &slab_caches, list) { |
| 4081 | n = get_node(s, offline_node); |
| 4082 | if (n) { |
| 4083 | /* |
| 4084 | * if n->nr_slabs > 0, slabs still exist on the node |
| 4085 | * that is going down. We were unable to free them, |
| 4086 | * and offline_pages() function shouldn't call this |
| 4087 | * callback. So, we must fail. |
| 4088 | */ |
| 4089 | BUG_ON(slabs_node(s, offline_node)); |
| 4090 | |
| 4091 | s->node[offline_node] = NULL; |
| 4092 | kmem_cache_free(kmem_cache_node, n); |
| 4093 | } |
| 4094 | } |
| 4095 | mutex_unlock(&slab_mutex); |
| 4096 | } |
| 4097 | |
| 4098 | static int slab_mem_going_online_callback(void *arg) |
| 4099 | { |
| 4100 | struct kmem_cache_node *n; |
| 4101 | struct kmem_cache *s; |
| 4102 | struct memory_notify *marg = arg; |
| 4103 | int nid = marg->status_change_nid_normal; |
| 4104 | int ret = 0; |
| 4105 | |
| 4106 | /* |
| 4107 | * If the node's memory is already available, then kmem_cache_node is |
| 4108 | * already created. Nothing to do. |
| 4109 | */ |
| 4110 | if (nid < 0) |
| 4111 | return 0; |
| 4112 | |
| 4113 | /* |
| 4114 | * We are bringing a node online. No memory is available yet. We must |
| 4115 | * allocate a kmem_cache_node structure in order to bring the node |
| 4116 | * online. |
| 4117 | */ |
| 4118 | mutex_lock(&slab_mutex); |
| 4119 | list_for_each_entry(s, &slab_caches, list) { |
| 4120 | /* |
| 4121 | * XXX: kmem_cache_alloc_node will fallback to other nodes |
| 4122 | * since memory is not yet available from the node that |
| 4123 | * is brought up. |
| 4124 | */ |
| 4125 | n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL); |
| 4126 | if (!n) { |
| 4127 | ret = -ENOMEM; |
| 4128 | goto out; |
| 4129 | } |
| 4130 | init_kmem_cache_node(n); |
| 4131 | s->node[nid] = n; |
| 4132 | } |
| 4133 | out: |
| 4134 | mutex_unlock(&slab_mutex); |
| 4135 | return ret; |
| 4136 | } |
| 4137 | |
| 4138 | static int slab_memory_callback(struct notifier_block *self, |
| 4139 | unsigned long action, void *arg) |
| 4140 | { |
| 4141 | int ret = 0; |
| 4142 | |
| 4143 | switch (action) { |
| 4144 | case MEM_GOING_ONLINE: |
| 4145 | ret = slab_mem_going_online_callback(arg); |
| 4146 | break; |
| 4147 | case MEM_GOING_OFFLINE: |
| 4148 | ret = slab_mem_going_offline_callback(arg); |
| 4149 | break; |
| 4150 | case MEM_OFFLINE: |
| 4151 | case MEM_CANCEL_ONLINE: |
| 4152 | slab_mem_offline_callback(arg); |
| 4153 | break; |
| 4154 | case MEM_ONLINE: |
| 4155 | case MEM_CANCEL_OFFLINE: |
| 4156 | break; |
| 4157 | } |
| 4158 | if (ret) |
| 4159 | ret = notifier_from_errno(ret); |
| 4160 | else |
| 4161 | ret = NOTIFY_OK; |
| 4162 | return ret; |
| 4163 | } |
| 4164 | |
| 4165 | static struct notifier_block slab_memory_callback_nb = { |
| 4166 | .notifier_call = slab_memory_callback, |
| 4167 | .priority = SLAB_CALLBACK_PRI, |
| 4168 | }; |
| 4169 | |
| 4170 | /******************************************************************** |
| 4171 | * Basic setup of slabs |
| 4172 | *******************************************************************/ |
| 4173 | |
| 4174 | /* |
| 4175 | * Used for early kmem_cache structures that were allocated using |
| 4176 | * the page allocator. Allocate them properly then fix up the pointers |
| 4177 | * that may be pointing to the wrong kmem_cache structure. |
| 4178 | */ |
| 4179 | |
| 4180 | static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache) |
| 4181 | { |
| 4182 | int node; |
| 4183 | struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); |
| 4184 | struct kmem_cache_node *n; |
| 4185 | |
| 4186 | memcpy(s, static_cache, kmem_cache->object_size); |
| 4187 | |
| 4188 | /* |
| 4189 | * This runs very early, and only the boot processor is supposed to be |
| 4190 | * up. Even if it weren't true, IRQs are not up so we couldn't fire |
| 4191 | * IPIs around. |
| 4192 | */ |
| 4193 | __flush_cpu_slab(s, smp_processor_id()); |
| 4194 | for_each_kmem_cache_node(s, node, n) { |
| 4195 | struct page *p; |
| 4196 | |
| 4197 | list_for_each_entry(p, &n->partial, lru) |
| 4198 | p->slab_cache = s; |
| 4199 | |
| 4200 | #ifdef CONFIG_SLUB_DEBUG |
| 4201 | list_for_each_entry(p, &n->full, lru) |
| 4202 | p->slab_cache = s; |
| 4203 | #endif |
| 4204 | } |
| 4205 | slab_init_memcg_params(s); |
| 4206 | list_add(&s->list, &slab_caches); |
| 4207 | memcg_link_cache(s); |
| 4208 | return s; |
| 4209 | } |
| 4210 | |
| 4211 | void __init kmem_cache_init(void) |
| 4212 | { |
| 4213 | static __initdata struct kmem_cache boot_kmem_cache, |
| 4214 | boot_kmem_cache_node; |
| 4215 | |
| 4216 | if (debug_guardpage_minorder()) |
| 4217 | slub_max_order = 0; |
| 4218 | |
| 4219 | kmem_cache_node = &boot_kmem_cache_node; |
| 4220 | kmem_cache = &boot_kmem_cache; |
| 4221 | |
| 4222 | create_boot_cache(kmem_cache_node, "kmem_cache_node", |
| 4223 | sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0); |
| 4224 | |
| 4225 | register_hotmemory_notifier(&slab_memory_callback_nb); |
| 4226 | |
| 4227 | /* Able to allocate the per node structures */ |
| 4228 | slab_state = PARTIAL; |
| 4229 | |
| 4230 | create_boot_cache(kmem_cache, "kmem_cache", |
| 4231 | offsetof(struct kmem_cache, node) + |
| 4232 | nr_node_ids * sizeof(struct kmem_cache_node *), |
| 4233 | SLAB_HWCACHE_ALIGN, 0, 0); |
| 4234 | |
| 4235 | kmem_cache = bootstrap(&boot_kmem_cache); |
| 4236 | kmem_cache_node = bootstrap(&boot_kmem_cache_node); |
| 4237 | |
| 4238 | /* Now we can use the kmem_cache to allocate kmalloc slabs */ |
| 4239 | setup_kmalloc_cache_index_table(); |
| 4240 | create_kmalloc_caches(0); |
| 4241 | |
| 4242 | /* Setup random freelists for each cache */ |
| 4243 | init_freelist_randomization(); |
| 4244 | |
| 4245 | cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL, |
| 4246 | slub_cpu_dead); |
| 4247 | |
| 4248 | pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%d\n", |
| 4249 | cache_line_size(), |
| 4250 | slub_min_order, slub_max_order, slub_min_objects, |
| 4251 | nr_cpu_ids, nr_node_ids); |
| 4252 | } |
| 4253 | |
| 4254 | void __init kmem_cache_init_late(void) |
| 4255 | { |
| 4256 | } |
| 4257 | |
| 4258 | struct kmem_cache * |
| 4259 | __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, |
| 4260 | slab_flags_t flags, void (*ctor)(void *)) |
| 4261 | { |
| 4262 | struct kmem_cache *s, *c; |
| 4263 | |
| 4264 | s = find_mergeable(size, align, flags, name, ctor); |
| 4265 | if (s) { |
| 4266 | s->refcount++; |
| 4267 | |
| 4268 | /* |
| 4269 | * Adjust the object sizes so that we clear |
| 4270 | * the complete object on kzalloc. |
| 4271 | */ |
| 4272 | s->object_size = max(s->object_size, size); |
| 4273 | s->inuse = max(s->inuse, ALIGN(size, sizeof(void *))); |
| 4274 | |
| 4275 | for_each_memcg_cache(c, s) { |
| 4276 | c->object_size = s->object_size; |
| 4277 | c->inuse = max(c->inuse, ALIGN(size, sizeof(void *))); |
| 4278 | } |
| 4279 | |
| 4280 | if (sysfs_slab_alias(s, name)) { |
| 4281 | s->refcount--; |
| 4282 | s = NULL; |
| 4283 | } |
| 4284 | } |
| 4285 | |
| 4286 | return s; |
| 4287 | } |
| 4288 | |
| 4289 | int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags) |
| 4290 | { |
| 4291 | int err; |
| 4292 | |
| 4293 | err = kmem_cache_open(s, flags); |
| 4294 | if (err) |
| 4295 | return err; |
| 4296 | |
| 4297 | /* Mutex is not taken during early boot */ |
| 4298 | if (slab_state <= UP) |
| 4299 | return 0; |
| 4300 | |
| 4301 | memcg_propagate_slab_attrs(s); |
| 4302 | err = sysfs_slab_add(s); |
| 4303 | if (err) |
| 4304 | __kmem_cache_release(s); |
| 4305 | |
| 4306 | return err; |
| 4307 | } |
| 4308 | |
| 4309 | void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller) |
| 4310 | { |
| 4311 | struct kmem_cache *s; |
| 4312 | void *ret; |
| 4313 | |
| 4314 | if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) |
| 4315 | return kmalloc_large(size, gfpflags); |
| 4316 | |
| 4317 | s = kmalloc_slab(size, gfpflags); |
| 4318 | |
| 4319 | if (unlikely(ZERO_OR_NULL_PTR(s))) |
| 4320 | return s; |
| 4321 | |
| 4322 | ret = slab_alloc(s, gfpflags, caller); |
| 4323 | |
| 4324 | /* Honor the call site pointer we received. */ |
| 4325 | trace_kmalloc(caller, ret, size, s->size, gfpflags); |
| 4326 | |
| 4327 | return ret; |
| 4328 | } |
| 4329 | |
| 4330 | #ifdef CONFIG_NUMA |
| 4331 | void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags, |
| 4332 | int node, unsigned long caller) |
| 4333 | { |
| 4334 | struct kmem_cache *s; |
| 4335 | void *ret; |
| 4336 | |
| 4337 | if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) { |
| 4338 | ret = kmalloc_large_node(size, gfpflags, node); |
| 4339 | |
| 4340 | trace_kmalloc_node(caller, ret, |
| 4341 | size, PAGE_SIZE << get_order(size), |
| 4342 | gfpflags, node); |
| 4343 | |
| 4344 | return ret; |
| 4345 | } |
| 4346 | |
| 4347 | s = kmalloc_slab(size, gfpflags); |
| 4348 | |
| 4349 | if (unlikely(ZERO_OR_NULL_PTR(s))) |
| 4350 | return s; |
| 4351 | |
| 4352 | ret = slab_alloc_node(s, gfpflags, node, caller); |
| 4353 | |
| 4354 | /* Honor the call site pointer we received. */ |
| 4355 | trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node); |
| 4356 | |
| 4357 | return ret; |
| 4358 | } |
| 4359 | #endif |
| 4360 | |
| 4361 | #ifdef CONFIG_SYSFS |
| 4362 | static int count_inuse(struct page *page) |
| 4363 | { |
| 4364 | return page->inuse; |
| 4365 | } |
| 4366 | |
| 4367 | static int count_total(struct page *page) |
| 4368 | { |
| 4369 | return page->objects; |
| 4370 | } |
| 4371 | #endif |
| 4372 | |
| 4373 | #ifdef CONFIG_SLUB_DEBUG |
| 4374 | static int validate_slab(struct kmem_cache *s, struct page *page, |
| 4375 | unsigned long *map) |
| 4376 | { |
| 4377 | void *p; |
| 4378 | void *addr = page_address(page); |
| 4379 | |
| 4380 | if (!check_slab(s, page) || |
| 4381 | !on_freelist(s, page, NULL)) |
| 4382 | return 0; |
| 4383 | |
| 4384 | /* Now we know that a valid freelist exists */ |
| 4385 | bitmap_zero(map, page->objects); |
| 4386 | |
| 4387 | get_map(s, page, map); |
| 4388 | for_each_object(p, s, addr, page->objects) { |
| 4389 | if (test_bit(slab_index(p, s, addr), map)) |
| 4390 | if (!check_object(s, page, p, SLUB_RED_INACTIVE)) |
| 4391 | return 0; |
| 4392 | } |
| 4393 | |
| 4394 | for_each_object(p, s, addr, page->objects) |
| 4395 | if (!test_bit(slab_index(p, s, addr), map)) |
| 4396 | if (!check_object(s, page, p, SLUB_RED_ACTIVE)) |
| 4397 | return 0; |
| 4398 | return 1; |
| 4399 | } |
| 4400 | |
| 4401 | static void validate_slab_slab(struct kmem_cache *s, struct page *page, |
| 4402 | unsigned long *map) |
| 4403 | { |
| 4404 | slab_lock(page); |
| 4405 | validate_slab(s, page, map); |
| 4406 | slab_unlock(page); |
| 4407 | } |
| 4408 | |
| 4409 | static int validate_slab_node(struct kmem_cache *s, |
| 4410 | struct kmem_cache_node *n, unsigned long *map) |
| 4411 | { |
| 4412 | unsigned long count = 0; |
| 4413 | struct page *page; |
| 4414 | unsigned long flags; |
| 4415 | |
| 4416 | spin_lock_irqsave(&n->list_lock, flags); |
| 4417 | |
| 4418 | list_for_each_entry(page, &n->partial, lru) { |
| 4419 | validate_slab_slab(s, page, map); |
| 4420 | count++; |
| 4421 | } |
| 4422 | if (count != n->nr_partial) |
| 4423 | pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n", |
| 4424 | s->name, count, n->nr_partial); |
| 4425 | |
| 4426 | if (!(s->flags & SLAB_STORE_USER)) |
| 4427 | goto out; |
| 4428 | |
| 4429 | list_for_each_entry(page, &n->full, lru) { |
| 4430 | validate_slab_slab(s, page, map); |
| 4431 | count++; |
| 4432 | } |
| 4433 | if (count != atomic_long_read(&n->nr_slabs)) |
| 4434 | pr_err("SLUB: %s %ld slabs counted but counter=%ld\n", |
| 4435 | s->name, count, atomic_long_read(&n->nr_slabs)); |
| 4436 | |
| 4437 | out: |
| 4438 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 4439 | return count; |
| 4440 | } |
| 4441 | |
| 4442 | static long validate_slab_cache(struct kmem_cache *s) |
| 4443 | { |
| 4444 | int node; |
| 4445 | unsigned long count = 0; |
| 4446 | struct kmem_cache_node *n; |
| 4447 | unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL); |
| 4448 | |
| 4449 | if (!map) |
| 4450 | return -ENOMEM; |
| 4451 | |
| 4452 | flush_all(s); |
| 4453 | for_each_kmem_cache_node(s, node, n) |
| 4454 | count += validate_slab_node(s, n, map); |
| 4455 | bitmap_free(map); |
| 4456 | return count; |
| 4457 | } |
| 4458 | /* |
| 4459 | * Generate lists of code addresses where slabcache objects are allocated |
| 4460 | * and freed. |
| 4461 | */ |
| 4462 | |
| 4463 | struct location { |
| 4464 | unsigned long count; |
| 4465 | unsigned long addr; |
| 4466 | long long sum_time; |
| 4467 | long min_time; |
| 4468 | long max_time; |
| 4469 | long min_pid; |
| 4470 | long max_pid; |
| 4471 | DECLARE_BITMAP(cpus, NR_CPUS); |
| 4472 | nodemask_t nodes; |
| 4473 | }; |
| 4474 | |
| 4475 | struct loc_track { |
| 4476 | unsigned long max; |
| 4477 | unsigned long count; |
| 4478 | struct location *loc; |
| 4479 | }; |
| 4480 | |
| 4481 | static void free_loc_track(struct loc_track *t) |
| 4482 | { |
| 4483 | if (t->max) |
| 4484 | free_pages((unsigned long)t->loc, |
| 4485 | get_order(sizeof(struct location) * t->max)); |
| 4486 | } |
| 4487 | |
| 4488 | static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags) |
| 4489 | { |
| 4490 | struct location *l; |
| 4491 | int order; |
| 4492 | |
| 4493 | order = get_order(sizeof(struct location) * max); |
| 4494 | |
| 4495 | l = (void *)__get_free_pages(flags, order); |
| 4496 | if (!l) |
| 4497 | return 0; |
| 4498 | |
| 4499 | if (t->count) { |
| 4500 | memcpy(l, t->loc, sizeof(struct location) * t->count); |
| 4501 | free_loc_track(t); |
| 4502 | } |
| 4503 | t->max = max; |
| 4504 | t->loc = l; |
| 4505 | return 1; |
| 4506 | } |
| 4507 | |
| 4508 | static int add_location(struct loc_track *t, struct kmem_cache *s, |
| 4509 | const struct track *track) |
| 4510 | { |
| 4511 | long start, end, pos; |
| 4512 | struct location *l; |
| 4513 | unsigned long caddr; |
| 4514 | unsigned long age = jiffies - track->when; |
| 4515 | |
| 4516 | start = -1; |
| 4517 | end = t->count; |
| 4518 | |
| 4519 | for ( ; ; ) { |
| 4520 | pos = start + (end - start + 1) / 2; |
| 4521 | |
| 4522 | /* |
| 4523 | * There is nothing at "end". If we end up there |
| 4524 | * we need to add something to before end. |
| 4525 | */ |
| 4526 | if (pos == end) |
| 4527 | break; |
| 4528 | |
| 4529 | caddr = t->loc[pos].addr; |
| 4530 | if (track->addr == caddr) { |
| 4531 | |
| 4532 | l = &t->loc[pos]; |
| 4533 | l->count++; |
| 4534 | if (track->when) { |
| 4535 | l->sum_time += age; |
| 4536 | if (age < l->min_time) |
| 4537 | l->min_time = age; |
| 4538 | if (age > l->max_time) |
| 4539 | l->max_time = age; |
| 4540 | |
| 4541 | if (track->pid < l->min_pid) |
| 4542 | l->min_pid = track->pid; |
| 4543 | if (track->pid > l->max_pid) |
| 4544 | l->max_pid = track->pid; |
| 4545 | |
| 4546 | cpumask_set_cpu(track->cpu, |
| 4547 | to_cpumask(l->cpus)); |
| 4548 | } |
| 4549 | node_set(page_to_nid(virt_to_page(track)), l->nodes); |
| 4550 | return 1; |
| 4551 | } |
| 4552 | |
| 4553 | if (track->addr < caddr) |
| 4554 | end = pos; |
| 4555 | else |
| 4556 | start = pos; |
| 4557 | } |
| 4558 | |
| 4559 | /* |
| 4560 | * Not found. Insert new tracking element. |
| 4561 | */ |
| 4562 | if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC)) |
| 4563 | return 0; |
| 4564 | |
| 4565 | l = t->loc + pos; |
| 4566 | if (pos < t->count) |
| 4567 | memmove(l + 1, l, |
| 4568 | (t->count - pos) * sizeof(struct location)); |
| 4569 | t->count++; |
| 4570 | l->count = 1; |
| 4571 | l->addr = track->addr; |
| 4572 | l->sum_time = age; |
| 4573 | l->min_time = age; |
| 4574 | l->max_time = age; |
| 4575 | l->min_pid = track->pid; |
| 4576 | l->max_pid = track->pid; |
| 4577 | cpumask_clear(to_cpumask(l->cpus)); |
| 4578 | cpumask_set_cpu(track->cpu, to_cpumask(l->cpus)); |
| 4579 | nodes_clear(l->nodes); |
| 4580 | node_set(page_to_nid(virt_to_page(track)), l->nodes); |
| 4581 | return 1; |
| 4582 | } |
| 4583 | |
| 4584 | static void process_slab(struct loc_track *t, struct kmem_cache *s, |
| 4585 | struct page *page, enum track_item alloc, |
| 4586 | unsigned long *map) |
| 4587 | { |
| 4588 | void *addr = page_address(page); |
| 4589 | void *p; |
| 4590 | |
| 4591 | bitmap_zero(map, page->objects); |
| 4592 | get_map(s, page, map); |
| 4593 | |
| 4594 | for_each_object(p, s, addr, page->objects) |
| 4595 | if (!test_bit(slab_index(p, s, addr), map)) |
| 4596 | add_location(t, s, get_track(s, p, alloc)); |
| 4597 | } |
| 4598 | |
| 4599 | static int list_locations(struct kmem_cache *s, char *buf, |
| 4600 | enum track_item alloc) |
| 4601 | { |
| 4602 | int len = 0; |
| 4603 | unsigned long i; |
| 4604 | struct loc_track t = { 0, 0, NULL }; |
| 4605 | int node; |
| 4606 | struct kmem_cache_node *n; |
| 4607 | unsigned long *map = bitmap_alloc(oo_objects(s->max), GFP_KERNEL); |
| 4608 | |
| 4609 | if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location), |
| 4610 | GFP_KERNEL)) { |
| 4611 | bitmap_free(map); |
| 4612 | return sprintf(buf, "Out of memory\n"); |
| 4613 | } |
| 4614 | /* Push back cpu slabs */ |
| 4615 | flush_all(s); |
| 4616 | |
| 4617 | for_each_kmem_cache_node(s, node, n) { |
| 4618 | unsigned long flags; |
| 4619 | struct page *page; |
| 4620 | |
| 4621 | if (!atomic_long_read(&n->nr_slabs)) |
| 4622 | continue; |
| 4623 | |
| 4624 | spin_lock_irqsave(&n->list_lock, flags); |
| 4625 | list_for_each_entry(page, &n->partial, lru) |
| 4626 | process_slab(&t, s, page, alloc, map); |
| 4627 | list_for_each_entry(page, &n->full, lru) |
| 4628 | process_slab(&t, s, page, alloc, map); |
| 4629 | spin_unlock_irqrestore(&n->list_lock, flags); |
| 4630 | } |
| 4631 | |
| 4632 | for (i = 0; i < t.count; i++) { |
| 4633 | struct location *l = &t.loc[i]; |
| 4634 | |
| 4635 | if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100) |
| 4636 | break; |
| 4637 | len += sprintf(buf + len, "%7ld ", l->count); |
| 4638 | |
| 4639 | if (l->addr) |
| 4640 | len += sprintf(buf + len, "%pS", (void *)l->addr); |
| 4641 | else |
| 4642 | len += sprintf(buf + len, "<not-available>"); |
| 4643 | |
| 4644 | if (l->sum_time != l->min_time) { |
| 4645 | len += sprintf(buf + len, " age=%ld/%ld/%ld", |
| 4646 | l->min_time, |
| 4647 | (long)div_u64(l->sum_time, l->count), |
| 4648 | l->max_time); |
| 4649 | } else |
| 4650 | len += sprintf(buf + len, " age=%ld", |
| 4651 | l->min_time); |
| 4652 | |
| 4653 | if (l->min_pid != l->max_pid) |
| 4654 | len += sprintf(buf + len, " pid=%ld-%ld", |
| 4655 | l->min_pid, l->max_pid); |
| 4656 | else |
| 4657 | len += sprintf(buf + len, " pid=%ld", |
| 4658 | l->min_pid); |
| 4659 | |
| 4660 | if (num_online_cpus() > 1 && |
| 4661 | !cpumask_empty(to_cpumask(l->cpus)) && |
| 4662 | len < PAGE_SIZE - 60) |
| 4663 | len += scnprintf(buf + len, PAGE_SIZE - len - 50, |
| 4664 | " cpus=%*pbl", |
| 4665 | cpumask_pr_args(to_cpumask(l->cpus))); |
| 4666 | |
| 4667 | if (nr_online_nodes > 1 && !nodes_empty(l->nodes) && |
| 4668 | len < PAGE_SIZE - 60) |
| 4669 | len += scnprintf(buf + len, PAGE_SIZE - len - 50, |
| 4670 | " nodes=%*pbl", |
| 4671 | nodemask_pr_args(&l->nodes)); |
| 4672 | |
| 4673 | len += sprintf(buf + len, "\n"); |
| 4674 | } |
| 4675 | |
| 4676 | free_loc_track(&t); |
| 4677 | bitmap_free(map); |
| 4678 | if (!t.count) |
| 4679 | len += sprintf(buf, "No data\n"); |
| 4680 | return len; |
| 4681 | } |
| 4682 | #endif |
| 4683 | |
| 4684 | #ifdef SLUB_RESILIENCY_TEST |
| 4685 | static void __init resiliency_test(void) |
| 4686 | { |
| 4687 | u8 *p; |
| 4688 | int type = KMALLOC_NORMAL; |
| 4689 | |
| 4690 | BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || KMALLOC_SHIFT_HIGH < 10); |
| 4691 | |
| 4692 | pr_err("SLUB resiliency testing\n"); |
| 4693 | pr_err("-----------------------\n"); |
| 4694 | pr_err("A. Corruption after allocation\n"); |
| 4695 | |
| 4696 | p = kzalloc(16, GFP_KERNEL); |
| 4697 | p[16] = 0x12; |
| 4698 | pr_err("\n1. kmalloc-16: Clobber Redzone/next pointer 0x12->0x%p\n\n", |
| 4699 | p + 16); |
| 4700 | |
| 4701 | validate_slab_cache(kmalloc_caches[type][4]); |
| 4702 | |
| 4703 | /* Hmmm... The next two are dangerous */ |
| 4704 | p = kzalloc(32, GFP_KERNEL); |
| 4705 | p[32 + sizeof(void *)] = 0x34; |
| 4706 | pr_err("\n2. kmalloc-32: Clobber next pointer/next slab 0x34 -> -0x%p\n", |
| 4707 | p); |
| 4708 | pr_err("If allocated object is overwritten then not detectable\n\n"); |
| 4709 | |
| 4710 | validate_slab_cache(kmalloc_caches[type][5]); |
| 4711 | p = kzalloc(64, GFP_KERNEL); |
| 4712 | p += 64 + (get_cycles() & 0xff) * sizeof(void *); |
| 4713 | *p = 0x56; |
| 4714 | pr_err("\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n", |
| 4715 | p); |
| 4716 | pr_err("If allocated object is overwritten then not detectable\n\n"); |
| 4717 | validate_slab_cache(kmalloc_caches[type][6]); |
| 4718 | |
| 4719 | pr_err("\nB. Corruption after free\n"); |
| 4720 | p = kzalloc(128, GFP_KERNEL); |
| 4721 | kfree(p); |
| 4722 | *p = 0x78; |
| 4723 | pr_err("1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p); |
| 4724 | validate_slab_cache(kmalloc_caches[type][7]); |
| 4725 | |
| 4726 | p = kzalloc(256, GFP_KERNEL); |
| 4727 | kfree(p); |
| 4728 | p[50] = 0x9a; |
| 4729 | pr_err("\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n", p); |
| 4730 | validate_slab_cache(kmalloc_caches[type][8]); |
| 4731 | |
| 4732 | p = kzalloc(512, GFP_KERNEL); |
| 4733 | kfree(p); |
| 4734 | p[512] = 0xab; |
| 4735 | pr_err("\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p); |
| 4736 | validate_slab_cache(kmalloc_caches[type][9]); |
| 4737 | } |
| 4738 | #else |
| 4739 | #ifdef CONFIG_SYSFS |
| 4740 | static void resiliency_test(void) {}; |
| 4741 | #endif |
| 4742 | #endif |
| 4743 | |
| 4744 | #ifdef CONFIG_SYSFS |
| 4745 | enum slab_stat_type { |
| 4746 | SL_ALL, /* All slabs */ |
| 4747 | SL_PARTIAL, /* Only partially allocated slabs */ |
| 4748 | SL_CPU, /* Only slabs used for cpu caches */ |
| 4749 | SL_OBJECTS, /* Determine allocated objects not slabs */ |
| 4750 | SL_TOTAL /* Determine object capacity not slabs */ |
| 4751 | }; |
| 4752 | |
| 4753 | #define SO_ALL (1 << SL_ALL) |
| 4754 | #define SO_PARTIAL (1 << SL_PARTIAL) |
| 4755 | #define SO_CPU (1 << SL_CPU) |
| 4756 | #define SO_OBJECTS (1 << SL_OBJECTS) |
| 4757 | #define SO_TOTAL (1 << SL_TOTAL) |
| 4758 | |
| 4759 | #ifdef CONFIG_MEMCG |
| 4760 | static bool memcg_sysfs_enabled = IS_ENABLED(CONFIG_SLUB_MEMCG_SYSFS_ON); |
| 4761 | |
| 4762 | static int __init setup_slub_memcg_sysfs(char *str) |
| 4763 | { |
| 4764 | int v; |
| 4765 | |
| 4766 | if (get_option(&str, &v) > 0) |
| 4767 | memcg_sysfs_enabled = v; |
| 4768 | |
| 4769 | return 1; |
| 4770 | } |
| 4771 | |
| 4772 | __setup("slub_memcg_sysfs=", setup_slub_memcg_sysfs); |
| 4773 | #endif |
| 4774 | |
| 4775 | static ssize_t show_slab_objects(struct kmem_cache *s, |
| 4776 | char *buf, unsigned long flags) |
| 4777 | { |
| 4778 | unsigned long total = 0; |
| 4779 | int node; |
| 4780 | int x; |
| 4781 | unsigned long *nodes; |
| 4782 | |
| 4783 | nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL); |
| 4784 | if (!nodes) |
| 4785 | return -ENOMEM; |
| 4786 | |
| 4787 | if (flags & SO_CPU) { |
| 4788 | int cpu; |
| 4789 | |
| 4790 | for_each_possible_cpu(cpu) { |
| 4791 | struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, |
| 4792 | cpu); |
| 4793 | int node; |
| 4794 | struct page *page; |
| 4795 | |
| 4796 | page = READ_ONCE(c->page); |
| 4797 | if (!page) |
| 4798 | continue; |
| 4799 | |
| 4800 | node = page_to_nid(page); |
| 4801 | if (flags & SO_TOTAL) |
| 4802 | x = page->objects; |
| 4803 | else if (flags & SO_OBJECTS) |
| 4804 | x = page->inuse; |
| 4805 | else |
| 4806 | x = 1; |
| 4807 | |
| 4808 | total += x; |
| 4809 | nodes[node] += x; |
| 4810 | |
| 4811 | page = slub_percpu_partial_read_once(c); |
| 4812 | if (page) { |
| 4813 | node = page_to_nid(page); |
| 4814 | if (flags & SO_TOTAL) |
| 4815 | WARN_ON_ONCE(1); |
| 4816 | else if (flags & SO_OBJECTS) |
| 4817 | WARN_ON_ONCE(1); |
| 4818 | else |
| 4819 | x = page->pages; |
| 4820 | total += x; |
| 4821 | nodes[node] += x; |
| 4822 | } |
| 4823 | } |
| 4824 | } |
| 4825 | |
| 4826 | get_online_mems(); |
| 4827 | #ifdef CONFIG_SLUB_DEBUG |
| 4828 | if (flags & SO_ALL) { |
| 4829 | struct kmem_cache_node *n; |
| 4830 | |
| 4831 | for_each_kmem_cache_node(s, node, n) { |
| 4832 | |
| 4833 | if (flags & SO_TOTAL) |
| 4834 | x = atomic_long_read(&n->total_objects); |
| 4835 | else if (flags & SO_OBJECTS) |
| 4836 | x = atomic_long_read(&n->total_objects) - |
| 4837 | count_partial(n, count_free); |
| 4838 | else |
| 4839 | x = atomic_long_read(&n->nr_slabs); |
| 4840 | total += x; |
| 4841 | nodes[node] += x; |
| 4842 | } |
| 4843 | |
| 4844 | } else |
| 4845 | #endif |
| 4846 | if (flags & SO_PARTIAL) { |
| 4847 | struct kmem_cache_node *n; |
| 4848 | |
| 4849 | for_each_kmem_cache_node(s, node, n) { |
| 4850 | if (flags & SO_TOTAL) |
| 4851 | x = count_partial(n, count_total); |
| 4852 | else if (flags & SO_OBJECTS) |
| 4853 | x = count_partial(n, count_inuse); |
| 4854 | else |
| 4855 | x = n->nr_partial; |
| 4856 | total += x; |
| 4857 | nodes[node] += x; |
| 4858 | } |
| 4859 | } |
| 4860 | x = sprintf(buf, "%lu", total); |
| 4861 | #ifdef CONFIG_NUMA |
| 4862 | for (node = 0; node < nr_node_ids; node++) |
| 4863 | if (nodes[node]) |
| 4864 | x += sprintf(buf + x, " N%d=%lu", |
| 4865 | node, nodes[node]); |
| 4866 | #endif |
| 4867 | put_online_mems(); |
| 4868 | kfree(nodes); |
| 4869 | return x + sprintf(buf + x, "\n"); |
| 4870 | } |
| 4871 | |
| 4872 | #ifdef CONFIG_SLUB_DEBUG |
| 4873 | static int any_slab_objects(struct kmem_cache *s) |
| 4874 | { |
| 4875 | int node; |
| 4876 | struct kmem_cache_node *n; |
| 4877 | |
| 4878 | for_each_kmem_cache_node(s, node, n) |
| 4879 | if (atomic_long_read(&n->total_objects)) |
| 4880 | return 1; |
| 4881 | |
| 4882 | return 0; |
| 4883 | } |
| 4884 | #endif |
| 4885 | |
| 4886 | #define to_slab_attr(n) container_of(n, struct slab_attribute, attr) |
| 4887 | #define to_slab(n) container_of(n, struct kmem_cache, kobj) |
| 4888 | |
| 4889 | struct slab_attribute { |
| 4890 | struct attribute attr; |
| 4891 | ssize_t (*show)(struct kmem_cache *s, char *buf); |
| 4892 | ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count); |
| 4893 | }; |
| 4894 | |
| 4895 | #define SLAB_ATTR_RO(_name) \ |
| 4896 | static struct slab_attribute _name##_attr = \ |
| 4897 | __ATTR(_name, 0400, _name##_show, NULL) |
| 4898 | |
| 4899 | #define SLAB_ATTR(_name) \ |
| 4900 | static struct slab_attribute _name##_attr = \ |
| 4901 | __ATTR(_name, 0600, _name##_show, _name##_store) |
| 4902 | |
| 4903 | static ssize_t slab_size_show(struct kmem_cache *s, char *buf) |
| 4904 | { |
| 4905 | return sprintf(buf, "%u\n", s->size); |
| 4906 | } |
| 4907 | SLAB_ATTR_RO(slab_size); |
| 4908 | |
| 4909 | static ssize_t align_show(struct kmem_cache *s, char *buf) |
| 4910 | { |
| 4911 | return sprintf(buf, "%u\n", s->align); |
| 4912 | } |
| 4913 | SLAB_ATTR_RO(align); |
| 4914 | |
| 4915 | static ssize_t object_size_show(struct kmem_cache *s, char *buf) |
| 4916 | { |
| 4917 | return sprintf(buf, "%u\n", s->object_size); |
| 4918 | } |
| 4919 | SLAB_ATTR_RO(object_size); |
| 4920 | |
| 4921 | static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf) |
| 4922 | { |
| 4923 | return sprintf(buf, "%u\n", oo_objects(s->oo)); |
| 4924 | } |
| 4925 | SLAB_ATTR_RO(objs_per_slab); |
| 4926 | |
| 4927 | static ssize_t order_store(struct kmem_cache *s, |
| 4928 | const char *buf, size_t length) |
| 4929 | { |
| 4930 | unsigned int order; |
| 4931 | int err; |
| 4932 | |
| 4933 | err = kstrtouint(buf, 10, &order); |
| 4934 | if (err) |
| 4935 | return err; |
| 4936 | |
| 4937 | if (order > slub_max_order || order < slub_min_order) |
| 4938 | return -EINVAL; |
| 4939 | |
| 4940 | calculate_sizes(s, order); |
| 4941 | return length; |
| 4942 | } |
| 4943 | |
| 4944 | static ssize_t order_show(struct kmem_cache *s, char *buf) |
| 4945 | { |
| 4946 | return sprintf(buf, "%u\n", oo_order(s->oo)); |
| 4947 | } |
| 4948 | SLAB_ATTR(order); |
| 4949 | |
| 4950 | static ssize_t min_partial_show(struct kmem_cache *s, char *buf) |
| 4951 | { |
| 4952 | return sprintf(buf, "%lu\n", s->min_partial); |
| 4953 | } |
| 4954 | |
| 4955 | static ssize_t min_partial_store(struct kmem_cache *s, const char *buf, |
| 4956 | size_t length) |
| 4957 | { |
| 4958 | unsigned long min; |
| 4959 | int err; |
| 4960 | |
| 4961 | err = kstrtoul(buf, 10, &min); |
| 4962 | if (err) |
| 4963 | return err; |
| 4964 | |
| 4965 | set_min_partial(s, min); |
| 4966 | return length; |
| 4967 | } |
| 4968 | SLAB_ATTR(min_partial); |
| 4969 | |
| 4970 | static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf) |
| 4971 | { |
| 4972 | return sprintf(buf, "%u\n", slub_cpu_partial(s)); |
| 4973 | } |
| 4974 | |
| 4975 | static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf, |
| 4976 | size_t length) |
| 4977 | { |
| 4978 | unsigned int objects; |
| 4979 | int err; |
| 4980 | |
| 4981 | err = kstrtouint(buf, 10, &objects); |
| 4982 | if (err) |
| 4983 | return err; |
| 4984 | if (objects && !kmem_cache_has_cpu_partial(s)) |
| 4985 | return -EINVAL; |
| 4986 | |
| 4987 | slub_set_cpu_partial(s, objects); |
| 4988 | flush_all(s); |
| 4989 | return length; |
| 4990 | } |
| 4991 | SLAB_ATTR(cpu_partial); |
| 4992 | |
| 4993 | static ssize_t ctor_show(struct kmem_cache *s, char *buf) |
| 4994 | { |
| 4995 | if (!s->ctor) |
| 4996 | return 0; |
| 4997 | return sprintf(buf, "%pS\n", s->ctor); |
| 4998 | } |
| 4999 | SLAB_ATTR_RO(ctor); |
| 5000 | |
| 5001 | static ssize_t aliases_show(struct kmem_cache *s, char *buf) |
| 5002 | { |
| 5003 | return sprintf(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1); |
| 5004 | } |
| 5005 | SLAB_ATTR_RO(aliases); |
| 5006 | |
| 5007 | static ssize_t partial_show(struct kmem_cache *s, char *buf) |
| 5008 | { |
| 5009 | return show_slab_objects(s, buf, SO_PARTIAL); |
| 5010 | } |
| 5011 | SLAB_ATTR_RO(partial); |
| 5012 | |
| 5013 | static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf) |
| 5014 | { |
| 5015 | return show_slab_objects(s, buf, SO_CPU); |
| 5016 | } |
| 5017 | SLAB_ATTR_RO(cpu_slabs); |
| 5018 | |
| 5019 | static ssize_t objects_show(struct kmem_cache *s, char *buf) |
| 5020 | { |
| 5021 | return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS); |
| 5022 | } |
| 5023 | SLAB_ATTR_RO(objects); |
| 5024 | |
| 5025 | static ssize_t objects_partial_show(struct kmem_cache *s, char *buf) |
| 5026 | { |
| 5027 | return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS); |
| 5028 | } |
| 5029 | SLAB_ATTR_RO(objects_partial); |
| 5030 | |
| 5031 | static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf) |
| 5032 | { |
| 5033 | int objects = 0; |
| 5034 | int pages = 0; |
| 5035 | int cpu; |
| 5036 | int len; |
| 5037 | |
| 5038 | for_each_online_cpu(cpu) { |
| 5039 | struct page *page; |
| 5040 | |
| 5041 | page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu)); |
| 5042 | |
| 5043 | if (page) { |
| 5044 | pages += page->pages; |
| 5045 | objects += page->pobjects; |
| 5046 | } |
| 5047 | } |
| 5048 | |
| 5049 | len = sprintf(buf, "%d(%d)", objects, pages); |
| 5050 | |
| 5051 | #ifdef CONFIG_SMP |
| 5052 | for_each_online_cpu(cpu) { |
| 5053 | struct page *page; |
| 5054 | |
| 5055 | page = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu)); |
| 5056 | |
| 5057 | if (page && len < PAGE_SIZE - 20) |
| 5058 | len += sprintf(buf + len, " C%d=%d(%d)", cpu, |
| 5059 | page->pobjects, page->pages); |
| 5060 | } |
| 5061 | #endif |
| 5062 | return len + sprintf(buf + len, "\n"); |
| 5063 | } |
| 5064 | SLAB_ATTR_RO(slabs_cpu_partial); |
| 5065 | |
| 5066 | static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf) |
| 5067 | { |
| 5068 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT)); |
| 5069 | } |
| 5070 | |
| 5071 | static ssize_t reclaim_account_store(struct kmem_cache *s, |
| 5072 | const char *buf, size_t length) |
| 5073 | { |
| 5074 | s->flags &= ~SLAB_RECLAIM_ACCOUNT; |
| 5075 | if (buf[0] == '1') |
| 5076 | s->flags |= SLAB_RECLAIM_ACCOUNT; |
| 5077 | return length; |
| 5078 | } |
| 5079 | SLAB_ATTR(reclaim_account); |
| 5080 | |
| 5081 | static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf) |
| 5082 | { |
| 5083 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN)); |
| 5084 | } |
| 5085 | SLAB_ATTR_RO(hwcache_align); |
| 5086 | |
| 5087 | #ifdef CONFIG_ZONE_DMA |
| 5088 | static ssize_t cache_dma_show(struct kmem_cache *s, char *buf) |
| 5089 | { |
| 5090 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA)); |
| 5091 | } |
| 5092 | SLAB_ATTR_RO(cache_dma); |
| 5093 | #endif |
| 5094 | |
| 5095 | static ssize_t usersize_show(struct kmem_cache *s, char *buf) |
| 5096 | { |
| 5097 | return sprintf(buf, "%u\n", s->usersize); |
| 5098 | } |
| 5099 | SLAB_ATTR_RO(usersize); |
| 5100 | |
| 5101 | static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf) |
| 5102 | { |
| 5103 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU)); |
| 5104 | } |
| 5105 | SLAB_ATTR_RO(destroy_by_rcu); |
| 5106 | |
| 5107 | #ifdef CONFIG_SLUB_DEBUG |
| 5108 | static ssize_t slabs_show(struct kmem_cache *s, char *buf) |
| 5109 | { |
| 5110 | return show_slab_objects(s, buf, SO_ALL); |
| 5111 | } |
| 5112 | SLAB_ATTR_RO(slabs); |
| 5113 | |
| 5114 | static ssize_t total_objects_show(struct kmem_cache *s, char *buf) |
| 5115 | { |
| 5116 | return show_slab_objects(s, buf, SO_ALL|SO_TOTAL); |
| 5117 | } |
| 5118 | SLAB_ATTR_RO(total_objects); |
| 5119 | |
| 5120 | static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf) |
| 5121 | { |
| 5122 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS)); |
| 5123 | } |
| 5124 | |
| 5125 | static ssize_t sanity_checks_store(struct kmem_cache *s, |
| 5126 | const char *buf, size_t length) |
| 5127 | { |
| 5128 | s->flags &= ~SLAB_CONSISTENCY_CHECKS; |
| 5129 | if (buf[0] == '1') { |
| 5130 | s->flags &= ~__CMPXCHG_DOUBLE; |
| 5131 | s->flags |= SLAB_CONSISTENCY_CHECKS; |
| 5132 | } |
| 5133 | return length; |
| 5134 | } |
| 5135 | SLAB_ATTR(sanity_checks); |
| 5136 | |
| 5137 | static ssize_t trace_show(struct kmem_cache *s, char *buf) |
| 5138 | { |
| 5139 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE)); |
| 5140 | } |
| 5141 | |
| 5142 | static ssize_t trace_store(struct kmem_cache *s, const char *buf, |
| 5143 | size_t length) |
| 5144 | { |
| 5145 | /* |
| 5146 | * Tracing a merged cache is going to give confusing results |
| 5147 | * as well as cause other issues like converting a mergeable |
| 5148 | * cache into an umergeable one. |
| 5149 | */ |
| 5150 | if (s->refcount > 1) |
| 5151 | return -EINVAL; |
| 5152 | |
| 5153 | s->flags &= ~SLAB_TRACE; |
| 5154 | if (buf[0] == '1') { |
| 5155 | s->flags &= ~__CMPXCHG_DOUBLE; |
| 5156 | s->flags |= SLAB_TRACE; |
| 5157 | } |
| 5158 | return length; |
| 5159 | } |
| 5160 | SLAB_ATTR(trace); |
| 5161 | |
| 5162 | static ssize_t red_zone_show(struct kmem_cache *s, char *buf) |
| 5163 | { |
| 5164 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE)); |
| 5165 | } |
| 5166 | |
| 5167 | static ssize_t red_zone_store(struct kmem_cache *s, |
| 5168 | const char *buf, size_t length) |
| 5169 | { |
| 5170 | if (any_slab_objects(s)) |
| 5171 | return -EBUSY; |
| 5172 | |
| 5173 | s->flags &= ~SLAB_RED_ZONE; |
| 5174 | if (buf[0] == '1') { |
| 5175 | s->flags |= SLAB_RED_ZONE; |
| 5176 | } |
| 5177 | calculate_sizes(s, -1); |
| 5178 | return length; |
| 5179 | } |
| 5180 | SLAB_ATTR(red_zone); |
| 5181 | |
| 5182 | static ssize_t poison_show(struct kmem_cache *s, char *buf) |
| 5183 | { |
| 5184 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON)); |
| 5185 | } |
| 5186 | |
| 5187 | static ssize_t poison_store(struct kmem_cache *s, |
| 5188 | const char *buf, size_t length) |
| 5189 | { |
| 5190 | if (any_slab_objects(s)) |
| 5191 | return -EBUSY; |
| 5192 | |
| 5193 | s->flags &= ~SLAB_POISON; |
| 5194 | if (buf[0] == '1') { |
| 5195 | s->flags |= SLAB_POISON; |
| 5196 | } |
| 5197 | calculate_sizes(s, -1); |
| 5198 | return length; |
| 5199 | } |
| 5200 | SLAB_ATTR(poison); |
| 5201 | |
| 5202 | static ssize_t store_user_show(struct kmem_cache *s, char *buf) |
| 5203 | { |
| 5204 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER)); |
| 5205 | } |
| 5206 | |
| 5207 | static ssize_t store_user_store(struct kmem_cache *s, |
| 5208 | const char *buf, size_t length) |
| 5209 | { |
| 5210 | if (any_slab_objects(s)) |
| 5211 | return -EBUSY; |
| 5212 | |
| 5213 | s->flags &= ~SLAB_STORE_USER; |
| 5214 | if (buf[0] == '1') { |
| 5215 | s->flags &= ~__CMPXCHG_DOUBLE; |
| 5216 | s->flags |= SLAB_STORE_USER; |
| 5217 | } |
| 5218 | calculate_sizes(s, -1); |
| 5219 | return length; |
| 5220 | } |
| 5221 | SLAB_ATTR(store_user); |
| 5222 | |
| 5223 | static ssize_t validate_show(struct kmem_cache *s, char *buf) |
| 5224 | { |
| 5225 | return 0; |
| 5226 | } |
| 5227 | |
| 5228 | static ssize_t validate_store(struct kmem_cache *s, |
| 5229 | const char *buf, size_t length) |
| 5230 | { |
| 5231 | int ret = -EINVAL; |
| 5232 | |
| 5233 | if (buf[0] == '1') { |
| 5234 | ret = validate_slab_cache(s); |
| 5235 | if (ret >= 0) |
| 5236 | ret = length; |
| 5237 | } |
| 5238 | return ret; |
| 5239 | } |
| 5240 | SLAB_ATTR(validate); |
| 5241 | |
| 5242 | static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf) |
| 5243 | { |
| 5244 | if (!(s->flags & SLAB_STORE_USER)) |
| 5245 | return -ENOSYS; |
| 5246 | return list_locations(s, buf, TRACK_ALLOC); |
| 5247 | } |
| 5248 | SLAB_ATTR_RO(alloc_calls); |
| 5249 | |
| 5250 | static ssize_t free_calls_show(struct kmem_cache *s, char *buf) |
| 5251 | { |
| 5252 | if (!(s->flags & SLAB_STORE_USER)) |
| 5253 | return -ENOSYS; |
| 5254 | return list_locations(s, buf, TRACK_FREE); |
| 5255 | } |
| 5256 | SLAB_ATTR_RO(free_calls); |
| 5257 | #endif /* CONFIG_SLUB_DEBUG */ |
| 5258 | |
| 5259 | #ifdef CONFIG_FAILSLAB |
| 5260 | static ssize_t failslab_show(struct kmem_cache *s, char *buf) |
| 5261 | { |
| 5262 | return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB)); |
| 5263 | } |
| 5264 | |
| 5265 | static ssize_t failslab_store(struct kmem_cache *s, const char *buf, |
| 5266 | size_t length) |
| 5267 | { |
| 5268 | if (s->refcount > 1) |
| 5269 | return -EINVAL; |
| 5270 | |
| 5271 | s->flags &= ~SLAB_FAILSLAB; |
| 5272 | if (buf[0] == '1') |
| 5273 | s->flags |= SLAB_FAILSLAB; |
| 5274 | return length; |
| 5275 | } |
| 5276 | SLAB_ATTR(failslab); |
| 5277 | #endif |
| 5278 | |
| 5279 | static ssize_t shrink_show(struct kmem_cache *s, char *buf) |
| 5280 | { |
| 5281 | return 0; |
| 5282 | } |
| 5283 | |
| 5284 | static ssize_t shrink_store(struct kmem_cache *s, |
| 5285 | const char *buf, size_t length) |
| 5286 | { |
| 5287 | if (buf[0] == '1') |
| 5288 | kmem_cache_shrink(s); |
| 5289 | else |
| 5290 | return -EINVAL; |
| 5291 | return length; |
| 5292 | } |
| 5293 | SLAB_ATTR(shrink); |
| 5294 | |
| 5295 | #ifdef CONFIG_NUMA |
| 5296 | static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf) |
| 5297 | { |
| 5298 | return sprintf(buf, "%u\n", s->remote_node_defrag_ratio / 10); |
| 5299 | } |
| 5300 | |
| 5301 | static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s, |
| 5302 | const char *buf, size_t length) |
| 5303 | { |
| 5304 | unsigned int ratio; |
| 5305 | int err; |
| 5306 | |
| 5307 | err = kstrtouint(buf, 10, &ratio); |
| 5308 | if (err) |
| 5309 | return err; |
| 5310 | if (ratio > 100) |
| 5311 | return -ERANGE; |
| 5312 | |
| 5313 | s->remote_node_defrag_ratio = ratio * 10; |
| 5314 | |
| 5315 | return length; |
| 5316 | } |
| 5317 | SLAB_ATTR(remote_node_defrag_ratio); |
| 5318 | #endif |
| 5319 | |
| 5320 | #ifdef CONFIG_SLUB_STATS |
| 5321 | static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si) |
| 5322 | { |
| 5323 | unsigned long sum = 0; |
| 5324 | int cpu; |
| 5325 | int len; |
| 5326 | int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL); |
| 5327 | |
| 5328 | if (!data) |
| 5329 | return -ENOMEM; |
| 5330 | |
| 5331 | for_each_online_cpu(cpu) { |
| 5332 | unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si]; |
| 5333 | |
| 5334 | data[cpu] = x; |
| 5335 | sum += x; |
| 5336 | } |
| 5337 | |
| 5338 | len = sprintf(buf, "%lu", sum); |
| 5339 | |
| 5340 | #ifdef CONFIG_SMP |
| 5341 | for_each_online_cpu(cpu) { |
| 5342 | if (data[cpu] && len < PAGE_SIZE - 20) |
| 5343 | len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]); |
| 5344 | } |
| 5345 | #endif |
| 5346 | kfree(data); |
| 5347 | return len + sprintf(buf + len, "\n"); |
| 5348 | } |
| 5349 | |
| 5350 | static void clear_stat(struct kmem_cache *s, enum stat_item si) |
| 5351 | { |
| 5352 | int cpu; |
| 5353 | |
| 5354 | for_each_online_cpu(cpu) |
| 5355 | per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0; |
| 5356 | } |
| 5357 | |
| 5358 | #define STAT_ATTR(si, text) \ |
| 5359 | static ssize_t text##_show(struct kmem_cache *s, char *buf) \ |
| 5360 | { \ |
| 5361 | return show_stat(s, buf, si); \ |
| 5362 | } \ |
| 5363 | static ssize_t text##_store(struct kmem_cache *s, \ |
| 5364 | const char *buf, size_t length) \ |
| 5365 | { \ |
| 5366 | if (buf[0] != '0') \ |
| 5367 | return -EINVAL; \ |
| 5368 | clear_stat(s, si); \ |
| 5369 | return length; \ |
| 5370 | } \ |
| 5371 | SLAB_ATTR(text); \ |
| 5372 | |
| 5373 | STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath); |
| 5374 | STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath); |
| 5375 | STAT_ATTR(FREE_FASTPATH, free_fastpath); |
| 5376 | STAT_ATTR(FREE_SLOWPATH, free_slowpath); |
| 5377 | STAT_ATTR(FREE_FROZEN, free_frozen); |
| 5378 | STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial); |
| 5379 | STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial); |
| 5380 | STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial); |
| 5381 | STAT_ATTR(ALLOC_SLAB, alloc_slab); |
| 5382 | STAT_ATTR(ALLOC_REFILL, alloc_refill); |
| 5383 | STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch); |
| 5384 | STAT_ATTR(FREE_SLAB, free_slab); |
| 5385 | STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush); |
| 5386 | STAT_ATTR(DEACTIVATE_FULL, deactivate_full); |
| 5387 | STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty); |
| 5388 | STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head); |
| 5389 | STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail); |
| 5390 | STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees); |
| 5391 | STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass); |
| 5392 | STAT_ATTR(ORDER_FALLBACK, order_fallback); |
| 5393 | STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail); |
| 5394 | STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail); |
| 5395 | STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc); |
| 5396 | STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free); |
| 5397 | STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node); |
| 5398 | STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain); |
| 5399 | #endif |
| 5400 | |
| 5401 | static struct attribute *slab_attrs[] = { |
| 5402 | &slab_size_attr.attr, |
| 5403 | &object_size_attr.attr, |
| 5404 | &objs_per_slab_attr.attr, |
| 5405 | &order_attr.attr, |
| 5406 | &min_partial_attr.attr, |
| 5407 | &cpu_partial_attr.attr, |
| 5408 | &objects_attr.attr, |
| 5409 | &objects_partial_attr.attr, |
| 5410 | &partial_attr.attr, |
| 5411 | &cpu_slabs_attr.attr, |
| 5412 | &ctor_attr.attr, |
| 5413 | &aliases_attr.attr, |
| 5414 | &align_attr.attr, |
| 5415 | &hwcache_align_attr.attr, |
| 5416 | &reclaim_account_attr.attr, |
| 5417 | &destroy_by_rcu_attr.attr, |
| 5418 | &shrink_attr.attr, |
| 5419 | &slabs_cpu_partial_attr.attr, |
| 5420 | #ifdef CONFIG_SLUB_DEBUG |
| 5421 | &total_objects_attr.attr, |
| 5422 | &slabs_attr.attr, |
| 5423 | &sanity_checks_attr.attr, |
| 5424 | &trace_attr.attr, |
| 5425 | &red_zone_attr.attr, |
| 5426 | &poison_attr.attr, |
| 5427 | &store_user_attr.attr, |
| 5428 | &validate_attr.attr, |
| 5429 | &alloc_calls_attr.attr, |
| 5430 | &free_calls_attr.attr, |
| 5431 | #endif |
| 5432 | #ifdef CONFIG_ZONE_DMA |
| 5433 | &cache_dma_attr.attr, |
| 5434 | #endif |
| 5435 | #ifdef CONFIG_NUMA |
| 5436 | &remote_node_defrag_ratio_attr.attr, |
| 5437 | #endif |
| 5438 | #ifdef CONFIG_SLUB_STATS |
| 5439 | &alloc_fastpath_attr.attr, |
| 5440 | &alloc_slowpath_attr.attr, |
| 5441 | &free_fastpath_attr.attr, |
| 5442 | &free_slowpath_attr.attr, |
| 5443 | &free_frozen_attr.attr, |
| 5444 | &free_add_partial_attr.attr, |
| 5445 | &free_remove_partial_attr.attr, |
| 5446 | &alloc_from_partial_attr.attr, |
| 5447 | &alloc_slab_attr.attr, |
| 5448 | &alloc_refill_attr.attr, |
| 5449 | &alloc_node_mismatch_attr.attr, |
| 5450 | &free_slab_attr.attr, |
| 5451 | &cpuslab_flush_attr.attr, |
| 5452 | &deactivate_full_attr.attr, |
| 5453 | &deactivate_empty_attr.attr, |
| 5454 | &deactivate_to_head_attr.attr, |
| 5455 | &deactivate_to_tail_attr.attr, |
| 5456 | &deactivate_remote_frees_attr.attr, |
| 5457 | &deactivate_bypass_attr.attr, |
| 5458 | &order_fallback_attr.attr, |
| 5459 | &cmpxchg_double_fail_attr.attr, |
| 5460 | &cmpxchg_double_cpu_fail_attr.attr, |
| 5461 | &cpu_partial_alloc_attr.attr, |
| 5462 | &cpu_partial_free_attr.attr, |
| 5463 | &cpu_partial_node_attr.attr, |
| 5464 | &cpu_partial_drain_attr.attr, |
| 5465 | #endif |
| 5466 | #ifdef CONFIG_FAILSLAB |
| 5467 | &failslab_attr.attr, |
| 5468 | #endif |
| 5469 | &usersize_attr.attr, |
| 5470 | |
| 5471 | NULL |
| 5472 | }; |
| 5473 | |
| 5474 | static const struct attribute_group slab_attr_group = { |
| 5475 | .attrs = slab_attrs, |
| 5476 | }; |
| 5477 | |
| 5478 | static ssize_t slab_attr_show(struct kobject *kobj, |
| 5479 | struct attribute *attr, |
| 5480 | char *buf) |
| 5481 | { |
| 5482 | struct slab_attribute *attribute; |
| 5483 | struct kmem_cache *s; |
| 5484 | int err; |
| 5485 | |
| 5486 | attribute = to_slab_attr(attr); |
| 5487 | s = to_slab(kobj); |
| 5488 | |
| 5489 | if (!attribute->show) |
| 5490 | return -EIO; |
| 5491 | |
| 5492 | err = attribute->show(s, buf); |
| 5493 | |
| 5494 | return err; |
| 5495 | } |
| 5496 | |
| 5497 | static ssize_t slab_attr_store(struct kobject *kobj, |
| 5498 | struct attribute *attr, |
| 5499 | const char *buf, size_t len) |
| 5500 | { |
| 5501 | struct slab_attribute *attribute; |
| 5502 | struct kmem_cache *s; |
| 5503 | int err; |
| 5504 | |
| 5505 | attribute = to_slab_attr(attr); |
| 5506 | s = to_slab(kobj); |
| 5507 | |
| 5508 | if (!attribute->store) |
| 5509 | return -EIO; |
| 5510 | |
| 5511 | err = attribute->store(s, buf, len); |
| 5512 | #ifdef CONFIG_MEMCG |
| 5513 | if (slab_state >= FULL && err >= 0 && is_root_cache(s)) { |
| 5514 | struct kmem_cache *c; |
| 5515 | |
| 5516 | mutex_lock(&slab_mutex); |
| 5517 | if (s->max_attr_size < len) |
| 5518 | s->max_attr_size = len; |
| 5519 | |
| 5520 | /* |
| 5521 | * This is a best effort propagation, so this function's return |
| 5522 | * value will be determined by the parent cache only. This is |
| 5523 | * basically because not all attributes will have a well |
| 5524 | * defined semantics for rollbacks - most of the actions will |
| 5525 | * have permanent effects. |
| 5526 | * |
| 5527 | * Returning the error value of any of the children that fail |
| 5528 | * is not 100 % defined, in the sense that users seeing the |
| 5529 | * error code won't be able to know anything about the state of |
| 5530 | * the cache. |
| 5531 | * |
| 5532 | * Only returning the error code for the parent cache at least |
| 5533 | * has well defined semantics. The cache being written to |
| 5534 | * directly either failed or succeeded, in which case we loop |
| 5535 | * through the descendants with best-effort propagation. |
| 5536 | */ |
| 5537 | for_each_memcg_cache(c, s) |
| 5538 | attribute->store(c, buf, len); |
| 5539 | mutex_unlock(&slab_mutex); |
| 5540 | } |
| 5541 | #endif |
| 5542 | return err; |
| 5543 | } |
| 5544 | |
| 5545 | static void memcg_propagate_slab_attrs(struct kmem_cache *s) |
| 5546 | { |
| 5547 | #ifdef CONFIG_MEMCG |
| 5548 | int i; |
| 5549 | char *buffer = NULL; |
| 5550 | struct kmem_cache *root_cache; |
| 5551 | |
| 5552 | if (is_root_cache(s)) |
| 5553 | return; |
| 5554 | |
| 5555 | root_cache = s->memcg_params.root_cache; |
| 5556 | |
| 5557 | /* |
| 5558 | * This mean this cache had no attribute written. Therefore, no point |
| 5559 | * in copying default values around |
| 5560 | */ |
| 5561 | if (!root_cache->max_attr_size) |
| 5562 | return; |
| 5563 | |
| 5564 | for (i = 0; i < ARRAY_SIZE(slab_attrs); i++) { |
| 5565 | char mbuf[64]; |
| 5566 | char *buf; |
| 5567 | struct slab_attribute *attr = to_slab_attr(slab_attrs[i]); |
| 5568 | ssize_t len; |
| 5569 | |
| 5570 | if (!attr || !attr->store || !attr->show) |
| 5571 | continue; |
| 5572 | |
| 5573 | /* |
| 5574 | * It is really bad that we have to allocate here, so we will |
| 5575 | * do it only as a fallback. If we actually allocate, though, |
| 5576 | * we can just use the allocated buffer until the end. |
| 5577 | * |
| 5578 | * Most of the slub attributes will tend to be very small in |
| 5579 | * size, but sysfs allows buffers up to a page, so they can |
| 5580 | * theoretically happen. |
| 5581 | */ |
| 5582 | if (buffer) |
| 5583 | buf = buffer; |
| 5584 | else if (root_cache->max_attr_size < ARRAY_SIZE(mbuf)) |
| 5585 | buf = mbuf; |
| 5586 | else { |
| 5587 | buffer = (char *) get_zeroed_page(GFP_KERNEL); |
| 5588 | if (WARN_ON(!buffer)) |
| 5589 | continue; |
| 5590 | buf = buffer; |
| 5591 | } |
| 5592 | |
| 5593 | len = attr->show(root_cache, buf); |
| 5594 | if (len > 0) |
| 5595 | attr->store(s, buf, len); |
| 5596 | } |
| 5597 | |
| 5598 | if (buffer) |
| 5599 | free_page((unsigned long)buffer); |
| 5600 | #endif |
| 5601 | } |
| 5602 | |
| 5603 | static void kmem_cache_release(struct kobject *k) |
| 5604 | { |
| 5605 | slab_kmem_cache_release(to_slab(k)); |
| 5606 | } |
| 5607 | |
| 5608 | static const struct sysfs_ops slab_sysfs_ops = { |
| 5609 | .show = slab_attr_show, |
| 5610 | .store = slab_attr_store, |
| 5611 | }; |
| 5612 | |
| 5613 | static struct kobj_type slab_ktype = { |
| 5614 | .sysfs_ops = &slab_sysfs_ops, |
| 5615 | .release = kmem_cache_release, |
| 5616 | }; |
| 5617 | |
| 5618 | static int uevent_filter(struct kset *kset, struct kobject *kobj) |
| 5619 | { |
| 5620 | struct kobj_type *ktype = get_ktype(kobj); |
| 5621 | |
| 5622 | if (ktype == &slab_ktype) |
| 5623 | return 1; |
| 5624 | return 0; |
| 5625 | } |
| 5626 | |
| 5627 | static const struct kset_uevent_ops slab_uevent_ops = { |
| 5628 | .filter = uevent_filter, |
| 5629 | }; |
| 5630 | |
| 5631 | static struct kset *slab_kset; |
| 5632 | |
| 5633 | static inline struct kset *cache_kset(struct kmem_cache *s) |
| 5634 | { |
| 5635 | #ifdef CONFIG_MEMCG |
| 5636 | if (!is_root_cache(s)) |
| 5637 | return s->memcg_params.root_cache->memcg_kset; |
| 5638 | #endif |
| 5639 | return slab_kset; |
| 5640 | } |
| 5641 | |
| 5642 | #define ID_STR_LENGTH 64 |
| 5643 | |
| 5644 | /* Create a unique string id for a slab cache: |
| 5645 | * |
| 5646 | * Format :[flags-]size |
| 5647 | */ |
| 5648 | static char *create_unique_id(struct kmem_cache *s) |
| 5649 | { |
| 5650 | char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL); |
| 5651 | char *p = name; |
| 5652 | |
| 5653 | BUG_ON(!name); |
| 5654 | |
| 5655 | *p++ = ':'; |
| 5656 | /* |
| 5657 | * First flags affecting slabcache operations. We will only |
| 5658 | * get here for aliasable slabs so we do not need to support |
| 5659 | * too many flags. The flags here must cover all flags that |
| 5660 | * are matched during merging to guarantee that the id is |
| 5661 | * unique. |
| 5662 | */ |
| 5663 | if (s->flags & SLAB_CACHE_DMA) |
| 5664 | *p++ = 'd'; |
| 5665 | if (s->flags & SLAB_RECLAIM_ACCOUNT) |
| 5666 | *p++ = 'a'; |
| 5667 | if (s->flags & SLAB_CONSISTENCY_CHECKS) |
| 5668 | *p++ = 'F'; |
| 5669 | if (s->flags & SLAB_ACCOUNT) |
| 5670 | *p++ = 'A'; |
| 5671 | if (p != name + 1) |
| 5672 | *p++ = '-'; |
| 5673 | p += sprintf(p, "%07u", s->size); |
| 5674 | |
| 5675 | BUG_ON(p > name + ID_STR_LENGTH - 1); |
| 5676 | return name; |
| 5677 | } |
| 5678 | |
| 5679 | static void sysfs_slab_remove_workfn(struct work_struct *work) |
| 5680 | { |
| 5681 | struct kmem_cache *s = |
| 5682 | container_of(work, struct kmem_cache, kobj_remove_work); |
| 5683 | |
| 5684 | if (!s->kobj.state_in_sysfs) |
| 5685 | /* |
| 5686 | * For a memcg cache, this may be called during |
| 5687 | * deactivation and again on shutdown. Remove only once. |
| 5688 | * A cache is never shut down before deactivation is |
| 5689 | * complete, so no need to worry about synchronization. |
| 5690 | */ |
| 5691 | goto out; |
| 5692 | |
| 5693 | #ifdef CONFIG_MEMCG |
| 5694 | kset_unregister(s->memcg_kset); |
| 5695 | #endif |
| 5696 | kobject_uevent(&s->kobj, KOBJ_REMOVE); |
| 5697 | out: |
| 5698 | kobject_put(&s->kobj); |
| 5699 | } |
| 5700 | |
| 5701 | static int sysfs_slab_add(struct kmem_cache *s) |
| 5702 | { |
| 5703 | int err; |
| 5704 | const char *name; |
| 5705 | struct kset *kset = cache_kset(s); |
| 5706 | int unmergeable = slab_unmergeable(s); |
| 5707 | |
| 5708 | INIT_WORK(&s->kobj_remove_work, sysfs_slab_remove_workfn); |
| 5709 | |
| 5710 | if (!kset) { |
| 5711 | kobject_init(&s->kobj, &slab_ktype); |
| 5712 | return 0; |
| 5713 | } |
| 5714 | |
| 5715 | if (!unmergeable && disable_higher_order_debug && |
| 5716 | (slub_debug & DEBUG_METADATA_FLAGS)) |
| 5717 | unmergeable = 1; |
| 5718 | |
| 5719 | if (unmergeable) { |
| 5720 | /* |
| 5721 | * Slabcache can never be merged so we can use the name proper. |
| 5722 | * This is typically the case for debug situations. In that |
| 5723 | * case we can catch duplicate names easily. |
| 5724 | */ |
| 5725 | sysfs_remove_link(&slab_kset->kobj, s->name); |
| 5726 | name = s->name; |
| 5727 | } else { |
| 5728 | /* |
| 5729 | * Create a unique name for the slab as a target |
| 5730 | * for the symlinks. |
| 5731 | */ |
| 5732 | name = create_unique_id(s); |
| 5733 | } |
| 5734 | |
| 5735 | s->kobj.kset = kset; |
| 5736 | err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name); |
| 5737 | if (err) |
| 5738 | goto out; |
| 5739 | |
| 5740 | err = sysfs_create_group(&s->kobj, &slab_attr_group); |
| 5741 | if (err) |
| 5742 | goto out_del_kobj; |
| 5743 | |
| 5744 | #ifdef CONFIG_MEMCG |
| 5745 | if (is_root_cache(s) && memcg_sysfs_enabled) { |
| 5746 | s->memcg_kset = kset_create_and_add("cgroup", NULL, &s->kobj); |
| 5747 | if (!s->memcg_kset) { |
| 5748 | err = -ENOMEM; |
| 5749 | goto out_del_kobj; |
| 5750 | } |
| 5751 | } |
| 5752 | #endif |
| 5753 | |
| 5754 | kobject_uevent(&s->kobj, KOBJ_ADD); |
| 5755 | if (!unmergeable) { |
| 5756 | /* Setup first alias */ |
| 5757 | sysfs_slab_alias(s, s->name); |
| 5758 | } |
| 5759 | out: |
| 5760 | if (!unmergeable) |
| 5761 | kfree(name); |
| 5762 | return err; |
| 5763 | out_del_kobj: |
| 5764 | kobject_del(&s->kobj); |
| 5765 | goto out; |
| 5766 | } |
| 5767 | |
| 5768 | static void sysfs_slab_remove(struct kmem_cache *s) |
| 5769 | { |
| 5770 | if (slab_state < FULL) |
| 5771 | /* |
| 5772 | * Sysfs has not been setup yet so no need to remove the |
| 5773 | * cache from sysfs. |
| 5774 | */ |
| 5775 | return; |
| 5776 | |
| 5777 | kobject_get(&s->kobj); |
| 5778 | schedule_work(&s->kobj_remove_work); |
| 5779 | } |
| 5780 | |
| 5781 | void sysfs_slab_unlink(struct kmem_cache *s) |
| 5782 | { |
| 5783 | if (slab_state >= FULL) |
| 5784 | kobject_del(&s->kobj); |
| 5785 | } |
| 5786 | |
| 5787 | void sysfs_slab_release(struct kmem_cache *s) |
| 5788 | { |
| 5789 | if (slab_state >= FULL) |
| 5790 | kobject_put(&s->kobj); |
| 5791 | } |
| 5792 | |
| 5793 | /* |
| 5794 | * Need to buffer aliases during bootup until sysfs becomes |
| 5795 | * available lest we lose that information. |
| 5796 | */ |
| 5797 | struct saved_alias { |
| 5798 | struct kmem_cache *s; |
| 5799 | const char *name; |
| 5800 | struct saved_alias *next; |
| 5801 | }; |
| 5802 | |
| 5803 | static struct saved_alias *alias_list; |
| 5804 | |
| 5805 | static int sysfs_slab_alias(struct kmem_cache *s, const char *name) |
| 5806 | { |
| 5807 | struct saved_alias *al; |
| 5808 | |
| 5809 | if (slab_state == FULL) { |
| 5810 | /* |
| 5811 | * If we have a leftover link then remove it. |
| 5812 | */ |
| 5813 | sysfs_remove_link(&slab_kset->kobj, name); |
| 5814 | return sysfs_create_link(&slab_kset->kobj, &s->kobj, name); |
| 5815 | } |
| 5816 | |
| 5817 | al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL); |
| 5818 | if (!al) |
| 5819 | return -ENOMEM; |
| 5820 | |
| 5821 | al->s = s; |
| 5822 | al->name = name; |
| 5823 | al->next = alias_list; |
| 5824 | alias_list = al; |
| 5825 | return 0; |
| 5826 | } |
| 5827 | |
| 5828 | static int __init slab_sysfs_init(void) |
| 5829 | { |
| 5830 | struct kmem_cache *s; |
| 5831 | int err; |
| 5832 | |
| 5833 | mutex_lock(&slab_mutex); |
| 5834 | |
| 5835 | slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj); |
| 5836 | if (!slab_kset) { |
| 5837 | mutex_unlock(&slab_mutex); |
| 5838 | pr_err("Cannot register slab subsystem.\n"); |
| 5839 | return -ENOSYS; |
| 5840 | } |
| 5841 | |
| 5842 | slab_state = FULL; |
| 5843 | |
| 5844 | list_for_each_entry(s, &slab_caches, list) { |
| 5845 | err = sysfs_slab_add(s); |
| 5846 | if (err) |
| 5847 | pr_err("SLUB: Unable to add boot slab %s to sysfs\n", |
| 5848 | s->name); |
| 5849 | } |
| 5850 | |
| 5851 | while (alias_list) { |
| 5852 | struct saved_alias *al = alias_list; |
| 5853 | |
| 5854 | alias_list = alias_list->next; |
| 5855 | err = sysfs_slab_alias(al->s, al->name); |
| 5856 | if (err) |
| 5857 | pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n", |
| 5858 | al->name); |
| 5859 | kfree(al); |
| 5860 | } |
| 5861 | |
| 5862 | mutex_unlock(&slab_mutex); |
| 5863 | resiliency_test(); |
| 5864 | return 0; |
| 5865 | } |
| 5866 | |
| 5867 | __initcall(slab_sysfs_init); |
| 5868 | #endif /* CONFIG_SYSFS */ |
| 5869 | |
| 5870 | /* |
| 5871 | * The /proc/slabinfo ABI |
| 5872 | */ |
| 5873 | #ifdef CONFIG_SLUB_DEBUG |
| 5874 | void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo) |
| 5875 | { |
| 5876 | unsigned long nr_slabs = 0; |
| 5877 | unsigned long nr_objs = 0; |
| 5878 | unsigned long nr_free = 0; |
| 5879 | int node; |
| 5880 | struct kmem_cache_node *n; |
| 5881 | |
| 5882 | for_each_kmem_cache_node(s, node, n) { |
| 5883 | nr_slabs += node_nr_slabs(n); |
| 5884 | nr_objs += node_nr_objs(n); |
| 5885 | nr_free += count_partial(n, count_free); |
| 5886 | } |
| 5887 | |
| 5888 | sinfo->active_objs = nr_objs - nr_free; |
| 5889 | sinfo->num_objs = nr_objs; |
| 5890 | sinfo->active_slabs = nr_slabs; |
| 5891 | sinfo->num_slabs = nr_slabs; |
| 5892 | sinfo->objects_per_slab = oo_objects(s->oo); |
| 5893 | sinfo->cache_order = oo_order(s->oo); |
| 5894 | } |
| 5895 | |
| 5896 | void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s) |
| 5897 | { |
| 5898 | } |
| 5899 | |
| 5900 | ssize_t slabinfo_write(struct file *file, const char __user *buffer, |
| 5901 | size_t count, loff_t *ppos) |
| 5902 | { |
| 5903 | return -EIO; |
| 5904 | } |
| 5905 | #endif /* CONFIG_SLUB_DEBUG */ |