slab.c revision face37f5e615646f364fa848f0a5c9d361d7a46e
1/* 2 * linux/mm/slab.c 3 * Written by Mark Hemment, 1996/97. 4 * (markhe@nextd.demon.co.uk) 5 * 6 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli 7 * 8 * Major cleanup, different bufctl logic, per-cpu arrays 9 * (c) 2000 Manfred Spraul 10 * 11 * Cleanup, make the head arrays unconditional, preparation for NUMA 12 * (c) 2002 Manfred Spraul 13 * 14 * An implementation of the Slab Allocator as described in outline in; 15 * UNIX Internals: The New Frontiers by Uresh Vahalia 16 * Pub: Prentice Hall ISBN 0-13-101908-2 17 * or with a little more detail in; 18 * The Slab Allocator: An Object-Caching Kernel Memory Allocator 19 * Jeff Bonwick (Sun Microsystems). 20 * Presented at: USENIX Summer 1994 Technical Conference 21 * 22 * The memory is organized in caches, one cache for each object type. 23 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct) 24 * Each cache consists out of many slabs (they are small (usually one 25 * page long) and always contiguous), and each slab contains multiple 26 * initialized objects. 27 * 28 * This means, that your constructor is used only for newly allocated 29 * slabs and you must pass objects with the same initializations to 30 * kmem_cache_free. 31 * 32 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM, 33 * normal). If you need a special memory type, then must create a new 34 * cache for that memory type. 35 * 36 * In order to reduce fragmentation, the slabs are sorted in 3 groups: 37 * full slabs with 0 free objects 38 * partial slabs 39 * empty slabs with no allocated objects 40 * 41 * If partial slabs exist, then new allocations come from these slabs, 42 * otherwise from empty slabs or new slabs are allocated. 43 * 44 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache 45 * during kmem_cache_destroy(). The caller must prevent concurrent allocs. 46 * 47 * Each cache has a short per-cpu head array, most allocs 48 * and frees go into that array, and if that array overflows, then 1/2 49 * of the entries in the array are given back into the global cache. 50 * The head array is strictly LIFO and should improve the cache hit rates. 51 * On SMP, it additionally reduces the spinlock operations. 52 * 53 * The c_cpuarray may not be read with enabled local interrupts - 54 * it's changed with a smp_call_function(). 55 * 56 * SMP synchronization: 57 * constructors and destructors are called without any locking. 58 * Several members in struct kmem_cache and struct slab never change, they 59 * are accessed without any locking. 60 * The per-cpu arrays are never accessed from the wrong cpu, no locking, 61 * and local interrupts are disabled so slab code is preempt-safe. 62 * The non-constant members are protected with a per-cache irq spinlock. 63 * 64 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch 65 * in 2000 - many ideas in the current implementation are derived from 66 * his patch. 67 * 68 * Further notes from the original documentation: 69 * 70 * 11 April '97. Started multi-threading - markhe 71 * The global cache-chain is protected by the mutex 'cache_chain_mutex'. 72 * The sem is only needed when accessing/extending the cache-chain, which 73 * can never happen inside an interrupt (kmem_cache_create(), 74 * kmem_cache_shrink() and kmem_cache_reap()). 75 * 76 * At present, each engine can be growing a cache. This should be blocked. 77 * 78 * 15 March 2005. NUMA slab allocator. 79 * Shai Fultheim <shai@scalex86.org>. 80 * Shobhit Dayal <shobhit@calsoftinc.com> 81 * Alok N Kataria <alokk@calsoftinc.com> 82 * Christoph Lameter <christoph@lameter.com> 83 * 84 * Modified the slab allocator to be node aware on NUMA systems. 85 * Each node has its own list of partial, free and full slabs. 86 * All object allocations for a node occur from node specific slab lists. 87 */ 88 89#include <linux/slab.h> 90#include <linux/mm.h> 91#include <linux/poison.h> 92#include <linux/swap.h> 93#include <linux/cache.h> 94#include <linux/interrupt.h> 95#include <linux/init.h> 96#include <linux/compiler.h> 97#include <linux/cpuset.h> 98#include <linux/proc_fs.h> 99#include <linux/seq_file.h> 100#include <linux/notifier.h> 101#include <linux/kallsyms.h> 102#include <linux/cpu.h> 103#include <linux/sysctl.h> 104#include <linux/module.h> 105#include <linux/rcupdate.h> 106#include <linux/string.h> 107#include <linux/uaccess.h> 108#include <linux/nodemask.h> 109#include <linux/kmemleak.h> 110#include <linux/mempolicy.h> 111#include <linux/mutex.h> 112#include <linux/fault-inject.h> 113#include <linux/rtmutex.h> 114#include <linux/reciprocal_div.h> 115#include <linux/debugobjects.h> 116#include <linux/kmemcheck.h> 117#include <linux/memory.h> 118#include <linux/prefetch.h> 119 120#include <asm/cacheflush.h> 121#include <asm/tlbflush.h> 122#include <asm/page.h> 123 124/* 125 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON. 126 * 0 for faster, smaller code (especially in the critical paths). 127 * 128 * STATS - 1 to collect stats for /proc/slabinfo. 129 * 0 for faster, smaller code (especially in the critical paths). 130 * 131 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible) 132 */ 133 134#ifdef CONFIG_DEBUG_SLAB 135#define DEBUG 1 136#define STATS 1 137#define FORCED_DEBUG 1 138#else 139#define DEBUG 0 140#define STATS 0 141#define FORCED_DEBUG 0 142#endif 143 144/* Shouldn't this be in a header file somewhere? */ 145#define BYTES_PER_WORD sizeof(void *) 146#define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long)) 147 148#ifndef ARCH_KMALLOC_FLAGS 149#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN 150#endif 151 152/* Legal flag mask for kmem_cache_create(). */ 153#if DEBUG 154# define CREATE_MASK (SLAB_RED_ZONE | \ 155 SLAB_POISON | SLAB_HWCACHE_ALIGN | \ 156 SLAB_CACHE_DMA | \ 157 SLAB_STORE_USER | \ 158 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ 159 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \ 160 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK) 161#else 162# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \ 163 SLAB_CACHE_DMA | \ 164 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ 165 SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \ 166 SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK) 167#endif 168 169/* 170 * kmem_bufctl_t: 171 * 172 * Bufctl's are used for linking objs within a slab 173 * linked offsets. 174 * 175 * This implementation relies on "struct page" for locating the cache & 176 * slab an object belongs to. 177 * This allows the bufctl structure to be small (one int), but limits 178 * the number of objects a slab (not a cache) can contain when off-slab 179 * bufctls are used. The limit is the size of the largest general cache 180 * that does not use off-slab slabs. 181 * For 32bit archs with 4 kB pages, is this 56. 182 * This is not serious, as it is only for large objects, when it is unwise 183 * to have too many per slab. 184 * Note: This limit can be raised by introducing a general cache whose size 185 * is less than 512 (PAGE_SIZE<<3), but greater than 256. 186 */ 187 188typedef unsigned int kmem_bufctl_t; 189#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0) 190#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1) 191#define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2) 192#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3) 193 194/* 195 * struct slab_rcu 196 * 197 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to 198 * arrange for kmem_freepages to be called via RCU. This is useful if 199 * we need to approach a kernel structure obliquely, from its address 200 * obtained without the usual locking. We can lock the structure to 201 * stabilize it and check it's still at the given address, only if we 202 * can be sure that the memory has not been meanwhile reused for some 203 * other kind of object (which our subsystem's lock might corrupt). 204 * 205 * rcu_read_lock before reading the address, then rcu_read_unlock after 206 * taking the spinlock within the structure expected at that address. 207 */ 208struct slab_rcu { 209 struct rcu_head head; 210 struct kmem_cache *cachep; 211 void *addr; 212}; 213 214/* 215 * struct slab 216 * 217 * Manages the objs in a slab. Placed either at the beginning of mem allocated 218 * for a slab, or allocated from an general cache. 219 * Slabs are chained into three list: fully used, partial, fully free slabs. 220 */ 221struct slab { 222 union { 223 struct { 224 struct list_head list; 225 unsigned long colouroff; 226 void *s_mem; /* including colour offset */ 227 unsigned int inuse; /* num of objs active in slab */ 228 kmem_bufctl_t free; 229 unsigned short nodeid; 230 }; 231 struct slab_rcu __slab_cover_slab_rcu; 232 }; 233}; 234 235/* 236 * struct array_cache 237 * 238 * Purpose: 239 * - LIFO ordering, to hand out cache-warm objects from _alloc 240 * - reduce the number of linked list operations 241 * - reduce spinlock operations 242 * 243 * The limit is stored in the per-cpu structure to reduce the data cache 244 * footprint. 245 * 246 */ 247struct array_cache { 248 unsigned int avail; 249 unsigned int limit; 250 unsigned int batchcount; 251 unsigned int touched; 252 spinlock_t lock; 253 void *entry[]; /* 254 * Must have this definition in here for the proper 255 * alignment of array_cache. Also simplifies accessing 256 * the entries. 257 */ 258}; 259 260/* 261 * bootstrap: The caches do not work without cpuarrays anymore, but the 262 * cpuarrays are allocated from the generic caches... 263 */ 264#define BOOT_CPUCACHE_ENTRIES 1 265struct arraycache_init { 266 struct array_cache cache; 267 void *entries[BOOT_CPUCACHE_ENTRIES]; 268}; 269 270/* 271 * The slab lists for all objects. 272 */ 273struct kmem_list3 { 274 struct list_head slabs_partial; /* partial list first, better asm code */ 275 struct list_head slabs_full; 276 struct list_head slabs_free; 277 unsigned long free_objects; 278 unsigned int free_limit; 279 unsigned int colour_next; /* Per-node cache coloring */ 280 spinlock_t list_lock; 281 struct array_cache *shared; /* shared per node */ 282 struct array_cache **alien; /* on other nodes */ 283 unsigned long next_reap; /* updated without locking */ 284 int free_touched; /* updated without locking */ 285}; 286 287/* 288 * Need this for bootstrapping a per node allocator. 289 */ 290#define NUM_INIT_LISTS (3 * MAX_NUMNODES) 291static struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS]; 292#define CACHE_CACHE 0 293#define SIZE_AC MAX_NUMNODES 294#define SIZE_L3 (2 * MAX_NUMNODES) 295 296static int drain_freelist(struct kmem_cache *cache, 297 struct kmem_list3 *l3, int tofree); 298static void free_block(struct kmem_cache *cachep, void **objpp, int len, 299 int node); 300static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp); 301static void cache_reap(struct work_struct *unused); 302 303/* 304 * This function must be completely optimized away if a constant is passed to 305 * it. Mostly the same as what is in linux/slab.h except it returns an index. 306 */ 307static __always_inline int index_of(const size_t size) 308{ 309 extern void __bad_size(void); 310 311 if (__builtin_constant_p(size)) { 312 int i = 0; 313 314#define CACHE(x) \ 315 if (size <=x) \ 316 return i; \ 317 else \ 318 i++; 319#include <linux/kmalloc_sizes.h> 320#undef CACHE 321 __bad_size(); 322 } else 323 __bad_size(); 324 return 0; 325} 326 327static int slab_early_init = 1; 328 329#define INDEX_AC index_of(sizeof(struct arraycache_init)) 330#define INDEX_L3 index_of(sizeof(struct kmem_list3)) 331 332static void kmem_list3_init(struct kmem_list3 *parent) 333{ 334 INIT_LIST_HEAD(&parent->slabs_full); 335 INIT_LIST_HEAD(&parent->slabs_partial); 336 INIT_LIST_HEAD(&parent->slabs_free); 337 parent->shared = NULL; 338 parent->alien = NULL; 339 parent->colour_next = 0; 340 spin_lock_init(&parent->list_lock); 341 parent->free_objects = 0; 342 parent->free_touched = 0; 343} 344 345#define MAKE_LIST(cachep, listp, slab, nodeid) \ 346 do { \ 347 INIT_LIST_HEAD(listp); \ 348 list_splice(&(cachep->nodelists[nodeid]->slab), listp); \ 349 } while (0) 350 351#define MAKE_ALL_LISTS(cachep, ptr, nodeid) \ 352 do { \ 353 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \ 354 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \ 355 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \ 356 } while (0) 357 358#define CFLGS_OFF_SLAB (0x80000000UL) 359#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) 360 361#define BATCHREFILL_LIMIT 16 362/* 363 * Optimization question: fewer reaps means less probability for unnessary 364 * cpucache drain/refill cycles. 365 * 366 * OTOH the cpuarrays can contain lots of objects, 367 * which could lock up otherwise freeable slabs. 368 */ 369#define REAPTIMEOUT_CPUC (2*HZ) 370#define REAPTIMEOUT_LIST3 (4*HZ) 371 372#if STATS 373#define STATS_INC_ACTIVE(x) ((x)->num_active++) 374#define STATS_DEC_ACTIVE(x) ((x)->num_active--) 375#define STATS_INC_ALLOCED(x) ((x)->num_allocations++) 376#define STATS_INC_GROWN(x) ((x)->grown++) 377#define STATS_ADD_REAPED(x,y) ((x)->reaped += (y)) 378#define STATS_SET_HIGH(x) \ 379 do { \ 380 if ((x)->num_active > (x)->high_mark) \ 381 (x)->high_mark = (x)->num_active; \ 382 } while (0) 383#define STATS_INC_ERR(x) ((x)->errors++) 384#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++) 385#define STATS_INC_NODEFREES(x) ((x)->node_frees++) 386#define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++) 387#define STATS_SET_FREEABLE(x, i) \ 388 do { \ 389 if ((x)->max_freeable < i) \ 390 (x)->max_freeable = i; \ 391 } while (0) 392#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit) 393#define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss) 394#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit) 395#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss) 396#else 397#define STATS_INC_ACTIVE(x) do { } while (0) 398#define STATS_DEC_ACTIVE(x) do { } while (0) 399#define STATS_INC_ALLOCED(x) do { } while (0) 400#define STATS_INC_GROWN(x) do { } while (0) 401#define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0) 402#define STATS_SET_HIGH(x) do { } while (0) 403#define STATS_INC_ERR(x) do { } while (0) 404#define STATS_INC_NODEALLOCS(x) do { } while (0) 405#define STATS_INC_NODEFREES(x) do { } while (0) 406#define STATS_INC_ACOVERFLOW(x) do { } while (0) 407#define STATS_SET_FREEABLE(x, i) do { } while (0) 408#define STATS_INC_ALLOCHIT(x) do { } while (0) 409#define STATS_INC_ALLOCMISS(x) do { } while (0) 410#define STATS_INC_FREEHIT(x) do { } while (0) 411#define STATS_INC_FREEMISS(x) do { } while (0) 412#endif 413 414#if DEBUG 415 416/* 417 * memory layout of objects: 418 * 0 : objp 419 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that 420 * the end of an object is aligned with the end of the real 421 * allocation. Catches writes behind the end of the allocation. 422 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1: 423 * redzone word. 424 * cachep->obj_offset: The real object. 425 * cachep->buffer_size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long] 426 * cachep->buffer_size - 1* BYTES_PER_WORD: last caller address 427 * [BYTES_PER_WORD long] 428 */ 429static int obj_offset(struct kmem_cache *cachep) 430{ 431 return cachep->obj_offset; 432} 433 434static int obj_size(struct kmem_cache *cachep) 435{ 436 return cachep->obj_size; 437} 438 439static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp) 440{ 441 BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); 442 return (unsigned long long*) (objp + obj_offset(cachep) - 443 sizeof(unsigned long long)); 444} 445 446static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp) 447{ 448 BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); 449 if (cachep->flags & SLAB_STORE_USER) 450 return (unsigned long long *)(objp + cachep->buffer_size - 451 sizeof(unsigned long long) - 452 REDZONE_ALIGN); 453 return (unsigned long long *) (objp + cachep->buffer_size - 454 sizeof(unsigned long long)); 455} 456 457static void **dbg_userword(struct kmem_cache *cachep, void *objp) 458{ 459 BUG_ON(!(cachep->flags & SLAB_STORE_USER)); 460 return (void **)(objp + cachep->buffer_size - BYTES_PER_WORD); 461} 462 463#else 464 465#define obj_offset(x) 0 466#define obj_size(cachep) (cachep->buffer_size) 467#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) 468#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) 469#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;}) 470 471#endif 472 473#ifdef CONFIG_TRACING 474size_t slab_buffer_size(struct kmem_cache *cachep) 475{ 476 return cachep->buffer_size; 477} 478EXPORT_SYMBOL(slab_buffer_size); 479#endif 480 481/* 482 * Do not go above this order unless 0 objects fit into the slab or 483 * overridden on the command line. 484 */ 485#define SLAB_MAX_ORDER_HI 1 486#define SLAB_MAX_ORDER_LO 0 487static int slab_max_order = SLAB_MAX_ORDER_LO; 488static bool slab_max_order_set __initdata; 489 490/* 491 * Functions for storing/retrieving the cachep and or slab from the page 492 * allocator. These are used to find the slab an obj belongs to. With kfree(), 493 * these are used to find the cache which an obj belongs to. 494 */ 495static inline void page_set_cache(struct page *page, struct kmem_cache *cache) 496{ 497 page->lru.next = (struct list_head *)cache; 498} 499 500static inline struct kmem_cache *page_get_cache(struct page *page) 501{ 502 page = compound_head(page); 503 BUG_ON(!PageSlab(page)); 504 return (struct kmem_cache *)page->lru.next; 505} 506 507static inline void page_set_slab(struct page *page, struct slab *slab) 508{ 509 page->lru.prev = (struct list_head *)slab; 510} 511 512static inline struct slab *page_get_slab(struct page *page) 513{ 514 BUG_ON(!PageSlab(page)); 515 return (struct slab *)page->lru.prev; 516} 517 518static inline struct kmem_cache *virt_to_cache(const void *obj) 519{ 520 struct page *page = virt_to_head_page(obj); 521 return page_get_cache(page); 522} 523 524static inline struct slab *virt_to_slab(const void *obj) 525{ 526 struct page *page = virt_to_head_page(obj); 527 return page_get_slab(page); 528} 529 530static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab, 531 unsigned int idx) 532{ 533 return slab->s_mem + cache->buffer_size * idx; 534} 535 536/* 537 * We want to avoid an expensive divide : (offset / cache->buffer_size) 538 * Using the fact that buffer_size is a constant for a particular cache, 539 * we can replace (offset / cache->buffer_size) by 540 * reciprocal_divide(offset, cache->reciprocal_buffer_size) 541 */ 542static inline unsigned int obj_to_index(const struct kmem_cache *cache, 543 const struct slab *slab, void *obj) 544{ 545 u32 offset = (obj - slab->s_mem); 546 return reciprocal_divide(offset, cache->reciprocal_buffer_size); 547} 548 549/* 550 * These are the default caches for kmalloc. Custom caches can have other sizes. 551 */ 552struct cache_sizes malloc_sizes[] = { 553#define CACHE(x) { .cs_size = (x) }, 554#include <linux/kmalloc_sizes.h> 555 CACHE(ULONG_MAX) 556#undef CACHE 557}; 558EXPORT_SYMBOL(malloc_sizes); 559 560/* Must match cache_sizes above. Out of line to keep cache footprint low. */ 561struct cache_names { 562 char *name; 563 char *name_dma; 564}; 565 566static struct cache_names __initdata cache_names[] = { 567#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" }, 568#include <linux/kmalloc_sizes.h> 569 {NULL,} 570#undef CACHE 571}; 572 573static struct arraycache_init initarray_cache __initdata = 574 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; 575static struct arraycache_init initarray_generic = 576 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; 577 578/* internal cache of cache description objs */ 579static struct kmem_list3 *cache_cache_nodelists[MAX_NUMNODES]; 580static struct kmem_cache cache_cache = { 581 .nodelists = cache_cache_nodelists, 582 .batchcount = 1, 583 .limit = BOOT_CPUCACHE_ENTRIES, 584 .shared = 1, 585 .buffer_size = sizeof(struct kmem_cache), 586 .name = "kmem_cache", 587}; 588 589#define BAD_ALIEN_MAGIC 0x01020304ul 590 591/* 592 * chicken and egg problem: delay the per-cpu array allocation 593 * until the general caches are up. 594 */ 595static enum { 596 NONE, 597 PARTIAL_AC, 598 PARTIAL_L3, 599 EARLY, 600 FULL 601} g_cpucache_up; 602 603/* 604 * used by boot code to determine if it can use slab based allocator 605 */ 606int slab_is_available(void) 607{ 608 return g_cpucache_up >= EARLY; 609} 610 611#ifdef CONFIG_LOCKDEP 612 613/* 614 * Slab sometimes uses the kmalloc slabs to store the slab headers 615 * for other slabs "off slab". 616 * The locking for this is tricky in that it nests within the locks 617 * of all other slabs in a few places; to deal with this special 618 * locking we put on-slab caches into a separate lock-class. 619 * 620 * We set lock class for alien array caches which are up during init. 621 * The lock annotation will be lost if all cpus of a node goes down and 622 * then comes back up during hotplug 623 */ 624static struct lock_class_key on_slab_l3_key; 625static struct lock_class_key on_slab_alc_key; 626 627static struct lock_class_key debugobj_l3_key; 628static struct lock_class_key debugobj_alc_key; 629 630static void slab_set_lock_classes(struct kmem_cache *cachep, 631 struct lock_class_key *l3_key, struct lock_class_key *alc_key, 632 int q) 633{ 634 struct array_cache **alc; 635 struct kmem_list3 *l3; 636 int r; 637 638 l3 = cachep->nodelists[q]; 639 if (!l3) 640 return; 641 642 lockdep_set_class(&l3->list_lock, l3_key); 643 alc = l3->alien; 644 /* 645 * FIXME: This check for BAD_ALIEN_MAGIC 646 * should go away when common slab code is taught to 647 * work even without alien caches. 648 * Currently, non NUMA code returns BAD_ALIEN_MAGIC 649 * for alloc_alien_cache, 650 */ 651 if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC) 652 return; 653 for_each_node(r) { 654 if (alc[r]) 655 lockdep_set_class(&alc[r]->lock, alc_key); 656 } 657} 658 659static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node) 660{ 661 slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node); 662} 663 664static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep) 665{ 666 int node; 667 668 for_each_online_node(node) 669 slab_set_debugobj_lock_classes_node(cachep, node); 670} 671 672static void init_node_lock_keys(int q) 673{ 674 struct cache_sizes *s = malloc_sizes; 675 676 if (g_cpucache_up != FULL) 677 return; 678 679 for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) { 680 struct kmem_list3 *l3; 681 682 l3 = s->cs_cachep->nodelists[q]; 683 if (!l3 || OFF_SLAB(s->cs_cachep)) 684 continue; 685 686 slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key, 687 &on_slab_alc_key, q); 688 } 689} 690 691static inline void init_lock_keys(void) 692{ 693 int node; 694 695 for_each_node(node) 696 init_node_lock_keys(node); 697} 698#else 699static void init_node_lock_keys(int q) 700{ 701} 702 703static inline void init_lock_keys(void) 704{ 705} 706 707static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node) 708{ 709} 710 711static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep) 712{ 713} 714#endif 715 716/* 717 * Guard access to the cache-chain. 718 */ 719static DEFINE_MUTEX(cache_chain_mutex); 720static struct list_head cache_chain; 721 722static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); 723 724static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) 725{ 726 return cachep->array[smp_processor_id()]; 727} 728 729static inline struct kmem_cache *__find_general_cachep(size_t size, 730 gfp_t gfpflags) 731{ 732 struct cache_sizes *csizep = malloc_sizes; 733 734#if DEBUG 735 /* This happens if someone tries to call 736 * kmem_cache_create(), or __kmalloc(), before 737 * the generic caches are initialized. 738 */ 739 BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL); 740#endif 741 if (!size) 742 return ZERO_SIZE_PTR; 743 744 while (size > csizep->cs_size) 745 csizep++; 746 747 /* 748 * Really subtle: The last entry with cs->cs_size==ULONG_MAX 749 * has cs_{dma,}cachep==NULL. Thus no special case 750 * for large kmalloc calls required. 751 */ 752#ifdef CONFIG_ZONE_DMA 753 if (unlikely(gfpflags & GFP_DMA)) 754 return csizep->cs_dmacachep; 755#endif 756 return csizep->cs_cachep; 757} 758 759static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags) 760{ 761 return __find_general_cachep(size, gfpflags); 762} 763 764static size_t slab_mgmt_size(size_t nr_objs, size_t align) 765{ 766 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align); 767} 768 769/* 770 * Calculate the number of objects and left-over bytes for a given buffer size. 771 */ 772static void cache_estimate(unsigned long gfporder, size_t buffer_size, 773 size_t align, int flags, size_t *left_over, 774 unsigned int *num) 775{ 776 int nr_objs; 777 size_t mgmt_size; 778 size_t slab_size = PAGE_SIZE << gfporder; 779 780 /* 781 * The slab management structure can be either off the slab or 782 * on it. For the latter case, the memory allocated for a 783 * slab is used for: 784 * 785 * - The struct slab 786 * - One kmem_bufctl_t for each object 787 * - Padding to respect alignment of @align 788 * - @buffer_size bytes for each object 789 * 790 * If the slab management structure is off the slab, then the 791 * alignment will already be calculated into the size. Because 792 * the slabs are all pages aligned, the objects will be at the 793 * correct alignment when allocated. 794 */ 795 if (flags & CFLGS_OFF_SLAB) { 796 mgmt_size = 0; 797 nr_objs = slab_size / buffer_size; 798 799 if (nr_objs > SLAB_LIMIT) 800 nr_objs = SLAB_LIMIT; 801 } else { 802 /* 803 * Ignore padding for the initial guess. The padding 804 * is at most @align-1 bytes, and @buffer_size is at 805 * least @align. In the worst case, this result will 806 * be one greater than the number of objects that fit 807 * into the memory allocation when taking the padding 808 * into account. 809 */ 810 nr_objs = (slab_size - sizeof(struct slab)) / 811 (buffer_size + sizeof(kmem_bufctl_t)); 812 813 /* 814 * This calculated number will be either the right 815 * amount, or one greater than what we want. 816 */ 817 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size 818 > slab_size) 819 nr_objs--; 820 821 if (nr_objs > SLAB_LIMIT) 822 nr_objs = SLAB_LIMIT; 823 824 mgmt_size = slab_mgmt_size(nr_objs, align); 825 } 826 *num = nr_objs; 827 *left_over = slab_size - nr_objs*buffer_size - mgmt_size; 828} 829 830#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg) 831 832static void __slab_error(const char *function, struct kmem_cache *cachep, 833 char *msg) 834{ 835 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n", 836 function, cachep->name, msg); 837 dump_stack(); 838} 839 840/* 841 * By default on NUMA we use alien caches to stage the freeing of 842 * objects allocated from other nodes. This causes massive memory 843 * inefficiencies when using fake NUMA setup to split memory into a 844 * large number of small nodes, so it can be disabled on the command 845 * line 846 */ 847 848static int use_alien_caches __read_mostly = 1; 849static int __init noaliencache_setup(char *s) 850{ 851 use_alien_caches = 0; 852 return 1; 853} 854__setup("noaliencache", noaliencache_setup); 855 856static int __init slab_max_order_setup(char *str) 857{ 858 get_option(&str, &slab_max_order); 859 slab_max_order = slab_max_order < 0 ? 0 : 860 min(slab_max_order, MAX_ORDER - 1); 861 slab_max_order_set = true; 862 863 return 1; 864} 865__setup("slab_max_order=", slab_max_order_setup); 866 867#ifdef CONFIG_NUMA 868/* 869 * Special reaping functions for NUMA systems called from cache_reap(). 870 * These take care of doing round robin flushing of alien caches (containing 871 * objects freed on different nodes from which they were allocated) and the 872 * flushing of remote pcps by calling drain_node_pages. 873 */ 874static DEFINE_PER_CPU(unsigned long, slab_reap_node); 875 876static void init_reap_node(int cpu) 877{ 878 int node; 879 880 node = next_node(cpu_to_mem(cpu), node_online_map); 881 if (node == MAX_NUMNODES) 882 node = first_node(node_online_map); 883 884 per_cpu(slab_reap_node, cpu) = node; 885} 886 887static void next_reap_node(void) 888{ 889 int node = __this_cpu_read(slab_reap_node); 890 891 node = next_node(node, node_online_map); 892 if (unlikely(node >= MAX_NUMNODES)) 893 node = first_node(node_online_map); 894 __this_cpu_write(slab_reap_node, node); 895} 896 897#else 898#define init_reap_node(cpu) do { } while (0) 899#define next_reap_node(void) do { } while (0) 900#endif 901 902/* 903 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz 904 * via the workqueue/eventd. 905 * Add the CPU number into the expiration time to minimize the possibility of 906 * the CPUs getting into lockstep and contending for the global cache chain 907 * lock. 908 */ 909static void __cpuinit start_cpu_timer(int cpu) 910{ 911 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu); 912 913 /* 914 * When this gets called from do_initcalls via cpucache_init(), 915 * init_workqueues() has already run, so keventd will be setup 916 * at that time. 917 */ 918 if (keventd_up() && reap_work->work.func == NULL) { 919 init_reap_node(cpu); 920 INIT_DELAYED_WORK_DEFERRABLE(reap_work, cache_reap); 921 schedule_delayed_work_on(cpu, reap_work, 922 __round_jiffies_relative(HZ, cpu)); 923 } 924} 925 926static struct array_cache *alloc_arraycache(int node, int entries, 927 int batchcount, gfp_t gfp) 928{ 929 int memsize = sizeof(void *) * entries + sizeof(struct array_cache); 930 struct array_cache *nc = NULL; 931 932 nc = kmalloc_node(memsize, gfp, node); 933 /* 934 * The array_cache structures contain pointers to free object. 935 * However, when such objects are allocated or transferred to another 936 * cache the pointers are not cleared and they could be counted as 937 * valid references during a kmemleak scan. Therefore, kmemleak must 938 * not scan such objects. 939 */ 940 kmemleak_no_scan(nc); 941 if (nc) { 942 nc->avail = 0; 943 nc->limit = entries; 944 nc->batchcount = batchcount; 945 nc->touched = 0; 946 spin_lock_init(&nc->lock); 947 } 948 return nc; 949} 950 951/* 952 * Transfer objects in one arraycache to another. 953 * Locking must be handled by the caller. 954 * 955 * Return the number of entries transferred. 956 */ 957static int transfer_objects(struct array_cache *to, 958 struct array_cache *from, unsigned int max) 959{ 960 /* Figure out how many entries to transfer */ 961 int nr = min3(from->avail, max, to->limit - to->avail); 962 963 if (!nr) 964 return 0; 965 966 memcpy(to->entry + to->avail, from->entry + from->avail -nr, 967 sizeof(void *) *nr); 968 969 from->avail -= nr; 970 to->avail += nr; 971 return nr; 972} 973 974#ifndef CONFIG_NUMA 975 976#define drain_alien_cache(cachep, alien) do { } while (0) 977#define reap_alien(cachep, l3) do { } while (0) 978 979static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) 980{ 981 return (struct array_cache **)BAD_ALIEN_MAGIC; 982} 983 984static inline void free_alien_cache(struct array_cache **ac_ptr) 985{ 986} 987 988static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 989{ 990 return 0; 991} 992 993static inline void *alternate_node_alloc(struct kmem_cache *cachep, 994 gfp_t flags) 995{ 996 return NULL; 997} 998 999static inline void *____cache_alloc_node(struct kmem_cache *cachep, 1000 gfp_t flags, int nodeid) 1001{ 1002 return NULL; 1003} 1004 1005#else /* CONFIG_NUMA */ 1006 1007static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int); 1008static void *alternate_node_alloc(struct kmem_cache *, gfp_t); 1009 1010static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) 1011{ 1012 struct array_cache **ac_ptr; 1013 int memsize = sizeof(void *) * nr_node_ids; 1014 int i; 1015 1016 if (limit > 1) 1017 limit = 12; 1018 ac_ptr = kzalloc_node(memsize, gfp, node); 1019 if (ac_ptr) { 1020 for_each_node(i) { 1021 if (i == node || !node_online(i)) 1022 continue; 1023 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp); 1024 if (!ac_ptr[i]) { 1025 for (i--; i >= 0; i--) 1026 kfree(ac_ptr[i]); 1027 kfree(ac_ptr); 1028 return NULL; 1029 } 1030 } 1031 } 1032 return ac_ptr; 1033} 1034 1035static void free_alien_cache(struct array_cache **ac_ptr) 1036{ 1037 int i; 1038 1039 if (!ac_ptr) 1040 return; 1041 for_each_node(i) 1042 kfree(ac_ptr[i]); 1043 kfree(ac_ptr); 1044} 1045 1046static void __drain_alien_cache(struct kmem_cache *cachep, 1047 struct array_cache *ac, int node) 1048{ 1049 struct kmem_list3 *rl3 = cachep->nodelists[node]; 1050 1051 if (ac->avail) { 1052 spin_lock(&rl3->list_lock); 1053 /* 1054 * Stuff objects into the remote nodes shared array first. 1055 * That way we could avoid the overhead of putting the objects 1056 * into the free lists and getting them back later. 1057 */ 1058 if (rl3->shared) 1059 transfer_objects(rl3->shared, ac, ac->limit); 1060 1061 free_block(cachep, ac->entry, ac->avail, node); 1062 ac->avail = 0; 1063 spin_unlock(&rl3->list_lock); 1064 } 1065} 1066 1067/* 1068 * Called from cache_reap() to regularly drain alien caches round robin. 1069 */ 1070static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3) 1071{ 1072 int node = __this_cpu_read(slab_reap_node); 1073 1074 if (l3->alien) { 1075 struct array_cache *ac = l3->alien[node]; 1076 1077 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) { 1078 __drain_alien_cache(cachep, ac, node); 1079 spin_unlock_irq(&ac->lock); 1080 } 1081 } 1082} 1083 1084static void drain_alien_cache(struct kmem_cache *cachep, 1085 struct array_cache **alien) 1086{ 1087 int i = 0; 1088 struct array_cache *ac; 1089 unsigned long flags; 1090 1091 for_each_online_node(i) { 1092 ac = alien[i]; 1093 if (ac) { 1094 spin_lock_irqsave(&ac->lock, flags); 1095 __drain_alien_cache(cachep, ac, i); 1096 spin_unlock_irqrestore(&ac->lock, flags); 1097 } 1098 } 1099} 1100 1101static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 1102{ 1103 struct slab *slabp = virt_to_slab(objp); 1104 int nodeid = slabp->nodeid; 1105 struct kmem_list3 *l3; 1106 struct array_cache *alien = NULL; 1107 int node; 1108 1109 node = numa_mem_id(); 1110 1111 /* 1112 * Make sure we are not freeing a object from another node to the array 1113 * cache on this cpu. 1114 */ 1115 if (likely(slabp->nodeid == node)) 1116 return 0; 1117 1118 l3 = cachep->nodelists[node]; 1119 STATS_INC_NODEFREES(cachep); 1120 if (l3->alien && l3->alien[nodeid]) { 1121 alien = l3->alien[nodeid]; 1122 spin_lock(&alien->lock); 1123 if (unlikely(alien->avail == alien->limit)) { 1124 STATS_INC_ACOVERFLOW(cachep); 1125 __drain_alien_cache(cachep, alien, nodeid); 1126 } 1127 alien->entry[alien->avail++] = objp; 1128 spin_unlock(&alien->lock); 1129 } else { 1130 spin_lock(&(cachep->nodelists[nodeid])->list_lock); 1131 free_block(cachep, &objp, 1, nodeid); 1132 spin_unlock(&(cachep->nodelists[nodeid])->list_lock); 1133 } 1134 return 1; 1135} 1136#endif 1137 1138/* 1139 * Allocates and initializes nodelists for a node on each slab cache, used for 1140 * either memory or cpu hotplug. If memory is being hot-added, the kmem_list3 1141 * will be allocated off-node since memory is not yet online for the new node. 1142 * When hotplugging memory or a cpu, existing nodelists are not replaced if 1143 * already in use. 1144 * 1145 * Must hold cache_chain_mutex. 1146 */ 1147static int init_cache_nodelists_node(int node) 1148{ 1149 struct kmem_cache *cachep; 1150 struct kmem_list3 *l3; 1151 const int memsize = sizeof(struct kmem_list3); 1152 1153 list_for_each_entry(cachep, &cache_chain, next) { 1154 /* 1155 * Set up the size64 kmemlist for cpu before we can 1156 * begin anything. Make sure some other cpu on this 1157 * node has not already allocated this 1158 */ 1159 if (!cachep->nodelists[node]) { 1160 l3 = kmalloc_node(memsize, GFP_KERNEL, node); 1161 if (!l3) 1162 return -ENOMEM; 1163 kmem_list3_init(l3); 1164 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 + 1165 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 1166 1167 /* 1168 * The l3s don't come and go as CPUs come and 1169 * go. cache_chain_mutex is sufficient 1170 * protection here. 1171 */ 1172 cachep->nodelists[node] = l3; 1173 } 1174 1175 spin_lock_irq(&cachep->nodelists[node]->list_lock); 1176 cachep->nodelists[node]->free_limit = 1177 (1 + nr_cpus_node(node)) * 1178 cachep->batchcount + cachep->num; 1179 spin_unlock_irq(&cachep->nodelists[node]->list_lock); 1180 } 1181 return 0; 1182} 1183 1184static void __cpuinit cpuup_canceled(long cpu) 1185{ 1186 struct kmem_cache *cachep; 1187 struct kmem_list3 *l3 = NULL; 1188 int node = cpu_to_mem(cpu); 1189 const struct cpumask *mask = cpumask_of_node(node); 1190 1191 list_for_each_entry(cachep, &cache_chain, next) { 1192 struct array_cache *nc; 1193 struct array_cache *shared; 1194 struct array_cache **alien; 1195 1196 /* cpu is dead; no one can alloc from it. */ 1197 nc = cachep->array[cpu]; 1198 cachep->array[cpu] = NULL; 1199 l3 = cachep->nodelists[node]; 1200 1201 if (!l3) 1202 goto free_array_cache; 1203 1204 spin_lock_irq(&l3->list_lock); 1205 1206 /* Free limit for this kmem_list3 */ 1207 l3->free_limit -= cachep->batchcount; 1208 if (nc) 1209 free_block(cachep, nc->entry, nc->avail, node); 1210 1211 if (!cpumask_empty(mask)) { 1212 spin_unlock_irq(&l3->list_lock); 1213 goto free_array_cache; 1214 } 1215 1216 shared = l3->shared; 1217 if (shared) { 1218 free_block(cachep, shared->entry, 1219 shared->avail, node); 1220 l3->shared = NULL; 1221 } 1222 1223 alien = l3->alien; 1224 l3->alien = NULL; 1225 1226 spin_unlock_irq(&l3->list_lock); 1227 1228 kfree(shared); 1229 if (alien) { 1230 drain_alien_cache(cachep, alien); 1231 free_alien_cache(alien); 1232 } 1233free_array_cache: 1234 kfree(nc); 1235 } 1236 /* 1237 * In the previous loop, all the objects were freed to 1238 * the respective cache's slabs, now we can go ahead and 1239 * shrink each nodelist to its limit. 1240 */ 1241 list_for_each_entry(cachep, &cache_chain, next) { 1242 l3 = cachep->nodelists[node]; 1243 if (!l3) 1244 continue; 1245 drain_freelist(cachep, l3, l3->free_objects); 1246 } 1247} 1248 1249static int __cpuinit cpuup_prepare(long cpu) 1250{ 1251 struct kmem_cache *cachep; 1252 struct kmem_list3 *l3 = NULL; 1253 int node = cpu_to_mem(cpu); 1254 int err; 1255 1256 /* 1257 * We need to do this right in the beginning since 1258 * alloc_arraycache's are going to use this list. 1259 * kmalloc_node allows us to add the slab to the right 1260 * kmem_list3 and not this cpu's kmem_list3 1261 */ 1262 err = init_cache_nodelists_node(node); 1263 if (err < 0) 1264 goto bad; 1265 1266 /* 1267 * Now we can go ahead with allocating the shared arrays and 1268 * array caches 1269 */ 1270 list_for_each_entry(cachep, &cache_chain, next) { 1271 struct array_cache *nc; 1272 struct array_cache *shared = NULL; 1273 struct array_cache **alien = NULL; 1274 1275 nc = alloc_arraycache(node, cachep->limit, 1276 cachep->batchcount, GFP_KERNEL); 1277 if (!nc) 1278 goto bad; 1279 if (cachep->shared) { 1280 shared = alloc_arraycache(node, 1281 cachep->shared * cachep->batchcount, 1282 0xbaadf00d, GFP_KERNEL); 1283 if (!shared) { 1284 kfree(nc); 1285 goto bad; 1286 } 1287 } 1288 if (use_alien_caches) { 1289 alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL); 1290 if (!alien) { 1291 kfree(shared); 1292 kfree(nc); 1293 goto bad; 1294 } 1295 } 1296 cachep->array[cpu] = nc; 1297 l3 = cachep->nodelists[node]; 1298 BUG_ON(!l3); 1299 1300 spin_lock_irq(&l3->list_lock); 1301 if (!l3->shared) { 1302 /* 1303 * We are serialised from CPU_DEAD or 1304 * CPU_UP_CANCELLED by the cpucontrol lock 1305 */ 1306 l3->shared = shared; 1307 shared = NULL; 1308 } 1309#ifdef CONFIG_NUMA 1310 if (!l3->alien) { 1311 l3->alien = alien; 1312 alien = NULL; 1313 } 1314#endif 1315 spin_unlock_irq(&l3->list_lock); 1316 kfree(shared); 1317 free_alien_cache(alien); 1318 if (cachep->flags & SLAB_DEBUG_OBJECTS) 1319 slab_set_debugobj_lock_classes_node(cachep, node); 1320 } 1321 init_node_lock_keys(node); 1322 1323 return 0; 1324bad: 1325 cpuup_canceled(cpu); 1326 return -ENOMEM; 1327} 1328 1329static int __cpuinit cpuup_callback(struct notifier_block *nfb, 1330 unsigned long action, void *hcpu) 1331{ 1332 long cpu = (long)hcpu; 1333 int err = 0; 1334 1335 switch (action) { 1336 case CPU_UP_PREPARE: 1337 case CPU_UP_PREPARE_FROZEN: 1338 mutex_lock(&cache_chain_mutex); 1339 err = cpuup_prepare(cpu); 1340 mutex_unlock(&cache_chain_mutex); 1341 break; 1342 case CPU_ONLINE: 1343 case CPU_ONLINE_FROZEN: 1344 start_cpu_timer(cpu); 1345 break; 1346#ifdef CONFIG_HOTPLUG_CPU 1347 case CPU_DOWN_PREPARE: 1348 case CPU_DOWN_PREPARE_FROZEN: 1349 /* 1350 * Shutdown cache reaper. Note that the cache_chain_mutex is 1351 * held so that if cache_reap() is invoked it cannot do 1352 * anything expensive but will only modify reap_work 1353 * and reschedule the timer. 1354 */ 1355 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu)); 1356 /* Now the cache_reaper is guaranteed to be not running. */ 1357 per_cpu(slab_reap_work, cpu).work.func = NULL; 1358 break; 1359 case CPU_DOWN_FAILED: 1360 case CPU_DOWN_FAILED_FROZEN: 1361 start_cpu_timer(cpu); 1362 break; 1363 case CPU_DEAD: 1364 case CPU_DEAD_FROZEN: 1365 /* 1366 * Even if all the cpus of a node are down, we don't free the 1367 * kmem_list3 of any cache. This to avoid a race between 1368 * cpu_down, and a kmalloc allocation from another cpu for 1369 * memory from the node of the cpu going down. The list3 1370 * structure is usually allocated from kmem_cache_create() and 1371 * gets destroyed at kmem_cache_destroy(). 1372 */ 1373 /* fall through */ 1374#endif 1375 case CPU_UP_CANCELED: 1376 case CPU_UP_CANCELED_FROZEN: 1377 mutex_lock(&cache_chain_mutex); 1378 cpuup_canceled(cpu); 1379 mutex_unlock(&cache_chain_mutex); 1380 break; 1381 } 1382 return notifier_from_errno(err); 1383} 1384 1385static struct notifier_block __cpuinitdata cpucache_notifier = { 1386 &cpuup_callback, NULL, 0 1387}; 1388 1389#if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) 1390/* 1391 * Drains freelist for a node on each slab cache, used for memory hot-remove. 1392 * Returns -EBUSY if all objects cannot be drained so that the node is not 1393 * removed. 1394 * 1395 * Must hold cache_chain_mutex. 1396 */ 1397static int __meminit drain_cache_nodelists_node(int node) 1398{ 1399 struct kmem_cache *cachep; 1400 int ret = 0; 1401 1402 list_for_each_entry(cachep, &cache_chain, next) { 1403 struct kmem_list3 *l3; 1404 1405 l3 = cachep->nodelists[node]; 1406 if (!l3) 1407 continue; 1408 1409 drain_freelist(cachep, l3, l3->free_objects); 1410 1411 if (!list_empty(&l3->slabs_full) || 1412 !list_empty(&l3->slabs_partial)) { 1413 ret = -EBUSY; 1414 break; 1415 } 1416 } 1417 return ret; 1418} 1419 1420static int __meminit slab_memory_callback(struct notifier_block *self, 1421 unsigned long action, void *arg) 1422{ 1423 struct memory_notify *mnb = arg; 1424 int ret = 0; 1425 int nid; 1426 1427 nid = mnb->status_change_nid; 1428 if (nid < 0) 1429 goto out; 1430 1431 switch (action) { 1432 case MEM_GOING_ONLINE: 1433 mutex_lock(&cache_chain_mutex); 1434 ret = init_cache_nodelists_node(nid); 1435 mutex_unlock(&cache_chain_mutex); 1436 break; 1437 case MEM_GOING_OFFLINE: 1438 mutex_lock(&cache_chain_mutex); 1439 ret = drain_cache_nodelists_node(nid); 1440 mutex_unlock(&cache_chain_mutex); 1441 break; 1442 case MEM_ONLINE: 1443 case MEM_OFFLINE: 1444 case MEM_CANCEL_ONLINE: 1445 case MEM_CANCEL_OFFLINE: 1446 break; 1447 } 1448out: 1449 return notifier_from_errno(ret); 1450} 1451#endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */ 1452 1453/* 1454 * swap the static kmem_list3 with kmalloced memory 1455 */ 1456static void __init init_list(struct kmem_cache *cachep, struct kmem_list3 *list, 1457 int nodeid) 1458{ 1459 struct kmem_list3 *ptr; 1460 1461 ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid); 1462 BUG_ON(!ptr); 1463 1464 memcpy(ptr, list, sizeof(struct kmem_list3)); 1465 /* 1466 * Do not assume that spinlocks can be initialized via memcpy: 1467 */ 1468 spin_lock_init(&ptr->list_lock); 1469 1470 MAKE_ALL_LISTS(cachep, ptr, nodeid); 1471 cachep->nodelists[nodeid] = ptr; 1472} 1473 1474/* 1475 * For setting up all the kmem_list3s for cache whose buffer_size is same as 1476 * size of kmem_list3. 1477 */ 1478static void __init set_up_list3s(struct kmem_cache *cachep, int index) 1479{ 1480 int node; 1481 1482 for_each_online_node(node) { 1483 cachep->nodelists[node] = &initkmem_list3[index + node]; 1484 cachep->nodelists[node]->next_reap = jiffies + 1485 REAPTIMEOUT_LIST3 + 1486 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 1487 } 1488} 1489 1490/* 1491 * Initialisation. Called after the page allocator have been initialised and 1492 * before smp_init(). 1493 */ 1494void __init kmem_cache_init(void) 1495{ 1496 size_t left_over; 1497 struct cache_sizes *sizes; 1498 struct cache_names *names; 1499 int i; 1500 int order; 1501 int node; 1502 1503 if (num_possible_nodes() == 1) 1504 use_alien_caches = 0; 1505 1506 for (i = 0; i < NUM_INIT_LISTS; i++) { 1507 kmem_list3_init(&initkmem_list3[i]); 1508 if (i < MAX_NUMNODES) 1509 cache_cache.nodelists[i] = NULL; 1510 } 1511 set_up_list3s(&cache_cache, CACHE_CACHE); 1512 1513 /* 1514 * Fragmentation resistance on low memory - only use bigger 1515 * page orders on machines with more than 32MB of memory if 1516 * not overridden on the command line. 1517 */ 1518 if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT) 1519 slab_max_order = SLAB_MAX_ORDER_HI; 1520 1521 /* Bootstrap is tricky, because several objects are allocated 1522 * from caches that do not exist yet: 1523 * 1) initialize the cache_cache cache: it contains the struct 1524 * kmem_cache structures of all caches, except cache_cache itself: 1525 * cache_cache is statically allocated. 1526 * Initially an __init data area is used for the head array and the 1527 * kmem_list3 structures, it's replaced with a kmalloc allocated 1528 * array at the end of the bootstrap. 1529 * 2) Create the first kmalloc cache. 1530 * The struct kmem_cache for the new cache is allocated normally. 1531 * An __init data area is used for the head array. 1532 * 3) Create the remaining kmalloc caches, with minimally sized 1533 * head arrays. 1534 * 4) Replace the __init data head arrays for cache_cache and the first 1535 * kmalloc cache with kmalloc allocated arrays. 1536 * 5) Replace the __init data for kmem_list3 for cache_cache and 1537 * the other cache's with kmalloc allocated memory. 1538 * 6) Resize the head arrays of the kmalloc caches to their final sizes. 1539 */ 1540 1541 node = numa_mem_id(); 1542 1543 /* 1) create the cache_cache */ 1544 INIT_LIST_HEAD(&cache_chain); 1545 list_add(&cache_cache.next, &cache_chain); 1546 cache_cache.colour_off = cache_line_size(); 1547 cache_cache.array[smp_processor_id()] = &initarray_cache.cache; 1548 cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node]; 1549 1550 /* 1551 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids 1552 */ 1553 cache_cache.buffer_size = offsetof(struct kmem_cache, array[nr_cpu_ids]) + 1554 nr_node_ids * sizeof(struct kmem_list3 *); 1555#if DEBUG 1556 cache_cache.obj_size = cache_cache.buffer_size; 1557#endif 1558 cache_cache.buffer_size = ALIGN(cache_cache.buffer_size, 1559 cache_line_size()); 1560 cache_cache.reciprocal_buffer_size = 1561 reciprocal_value(cache_cache.buffer_size); 1562 1563 for (order = 0; order < MAX_ORDER; order++) { 1564 cache_estimate(order, cache_cache.buffer_size, 1565 cache_line_size(), 0, &left_over, &cache_cache.num); 1566 if (cache_cache.num) 1567 break; 1568 } 1569 BUG_ON(!cache_cache.num); 1570 cache_cache.gfporder = order; 1571 cache_cache.colour = left_over / cache_cache.colour_off; 1572 cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) + 1573 sizeof(struct slab), cache_line_size()); 1574 1575 /* 2+3) create the kmalloc caches */ 1576 sizes = malloc_sizes; 1577 names = cache_names; 1578 1579 /* 1580 * Initialize the caches that provide memory for the array cache and the 1581 * kmem_list3 structures first. Without this, further allocations will 1582 * bug. 1583 */ 1584 1585 sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name, 1586 sizes[INDEX_AC].cs_size, 1587 ARCH_KMALLOC_MINALIGN, 1588 ARCH_KMALLOC_FLAGS|SLAB_PANIC, 1589 NULL); 1590 1591 if (INDEX_AC != INDEX_L3) { 1592 sizes[INDEX_L3].cs_cachep = 1593 kmem_cache_create(names[INDEX_L3].name, 1594 sizes[INDEX_L3].cs_size, 1595 ARCH_KMALLOC_MINALIGN, 1596 ARCH_KMALLOC_FLAGS|SLAB_PANIC, 1597 NULL); 1598 } 1599 1600 slab_early_init = 0; 1601 1602 while (sizes->cs_size != ULONG_MAX) { 1603 /* 1604 * For performance, all the general caches are L1 aligned. 1605 * This should be particularly beneficial on SMP boxes, as it 1606 * eliminates "false sharing". 1607 * Note for systems short on memory removing the alignment will 1608 * allow tighter packing of the smaller caches. 1609 */ 1610 if (!sizes->cs_cachep) { 1611 sizes->cs_cachep = kmem_cache_create(names->name, 1612 sizes->cs_size, 1613 ARCH_KMALLOC_MINALIGN, 1614 ARCH_KMALLOC_FLAGS|SLAB_PANIC, 1615 NULL); 1616 } 1617#ifdef CONFIG_ZONE_DMA 1618 sizes->cs_dmacachep = kmem_cache_create( 1619 names->name_dma, 1620 sizes->cs_size, 1621 ARCH_KMALLOC_MINALIGN, 1622 ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA| 1623 SLAB_PANIC, 1624 NULL); 1625#endif 1626 sizes++; 1627 names++; 1628 } 1629 /* 4) Replace the bootstrap head arrays */ 1630 { 1631 struct array_cache *ptr; 1632 1633 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT); 1634 1635 BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache); 1636 memcpy(ptr, cpu_cache_get(&cache_cache), 1637 sizeof(struct arraycache_init)); 1638 /* 1639 * Do not assume that spinlocks can be initialized via memcpy: 1640 */ 1641 spin_lock_init(&ptr->lock); 1642 1643 cache_cache.array[smp_processor_id()] = ptr; 1644 1645 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT); 1646 1647 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep) 1648 != &initarray_generic.cache); 1649 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep), 1650 sizeof(struct arraycache_init)); 1651 /* 1652 * Do not assume that spinlocks can be initialized via memcpy: 1653 */ 1654 spin_lock_init(&ptr->lock); 1655 1656 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] = 1657 ptr; 1658 } 1659 /* 5) Replace the bootstrap kmem_list3's */ 1660 { 1661 int nid; 1662 1663 for_each_online_node(nid) { 1664 init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid); 1665 1666 init_list(malloc_sizes[INDEX_AC].cs_cachep, 1667 &initkmem_list3[SIZE_AC + nid], nid); 1668 1669 if (INDEX_AC != INDEX_L3) { 1670 init_list(malloc_sizes[INDEX_L3].cs_cachep, 1671 &initkmem_list3[SIZE_L3 + nid], nid); 1672 } 1673 } 1674 } 1675 1676 g_cpucache_up = EARLY; 1677} 1678 1679void __init kmem_cache_init_late(void) 1680{ 1681 struct kmem_cache *cachep; 1682 1683 /* Annotate slab for lockdep -- annotate the malloc caches */ 1684 init_lock_keys(); 1685 1686 /* 6) resize the head arrays to their final sizes */ 1687 mutex_lock(&cache_chain_mutex); 1688 list_for_each_entry(cachep, &cache_chain, next) 1689 if (enable_cpucache(cachep, GFP_NOWAIT)) 1690 BUG(); 1691 mutex_unlock(&cache_chain_mutex); 1692 1693 /* Done! */ 1694 g_cpucache_up = FULL; 1695 1696 /* 1697 * Register a cpu startup notifier callback that initializes 1698 * cpu_cache_get for all new cpus 1699 */ 1700 register_cpu_notifier(&cpucache_notifier); 1701 1702#ifdef CONFIG_NUMA 1703 /* 1704 * Register a memory hotplug callback that initializes and frees 1705 * nodelists. 1706 */ 1707 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); 1708#endif 1709 1710 /* 1711 * The reap timers are started later, with a module init call: That part 1712 * of the kernel is not yet operational. 1713 */ 1714} 1715 1716static int __init cpucache_init(void) 1717{ 1718 int cpu; 1719 1720 /* 1721 * Register the timers that return unneeded pages to the page allocator 1722 */ 1723 for_each_online_cpu(cpu) 1724 start_cpu_timer(cpu); 1725 return 0; 1726} 1727__initcall(cpucache_init); 1728 1729/* 1730 * Interface to system's page allocator. No need to hold the cache-lock. 1731 * 1732 * If we requested dmaable memory, we will get it. Even if we 1733 * did not request dmaable memory, we might get it, but that 1734 * would be relatively rare and ignorable. 1735 */ 1736static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) 1737{ 1738 struct page *page; 1739 int nr_pages; 1740 int i; 1741 1742#ifndef CONFIG_MMU 1743 /* 1744 * Nommu uses slab's for process anonymous memory allocations, and thus 1745 * requires __GFP_COMP to properly refcount higher order allocations 1746 */ 1747 flags |= __GFP_COMP; 1748#endif 1749 1750 flags |= cachep->gfpflags; 1751 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1752 flags |= __GFP_RECLAIMABLE; 1753 1754 page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder); 1755 if (!page) 1756 return NULL; 1757 1758 nr_pages = (1 << cachep->gfporder); 1759 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1760 add_zone_page_state(page_zone(page), 1761 NR_SLAB_RECLAIMABLE, nr_pages); 1762 else 1763 add_zone_page_state(page_zone(page), 1764 NR_SLAB_UNRECLAIMABLE, nr_pages); 1765 for (i = 0; i < nr_pages; i++) 1766 __SetPageSlab(page + i); 1767 1768 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) { 1769 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid); 1770 1771 if (cachep->ctor) 1772 kmemcheck_mark_uninitialized_pages(page, nr_pages); 1773 else 1774 kmemcheck_mark_unallocated_pages(page, nr_pages); 1775 } 1776 1777 return page_address(page); 1778} 1779 1780/* 1781 * Interface to system's page release. 1782 */ 1783static void kmem_freepages(struct kmem_cache *cachep, void *addr) 1784{ 1785 unsigned long i = (1 << cachep->gfporder); 1786 struct page *page = virt_to_page(addr); 1787 const unsigned long nr_freed = i; 1788 1789 kmemcheck_free_shadow(page, cachep->gfporder); 1790 1791 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1792 sub_zone_page_state(page_zone(page), 1793 NR_SLAB_RECLAIMABLE, nr_freed); 1794 else 1795 sub_zone_page_state(page_zone(page), 1796 NR_SLAB_UNRECLAIMABLE, nr_freed); 1797 while (i--) { 1798 BUG_ON(!PageSlab(page)); 1799 __ClearPageSlab(page); 1800 page++; 1801 } 1802 if (current->reclaim_state) 1803 current->reclaim_state->reclaimed_slab += nr_freed; 1804 free_pages((unsigned long)addr, cachep->gfporder); 1805} 1806 1807static void kmem_rcu_free(struct rcu_head *head) 1808{ 1809 struct slab_rcu *slab_rcu = (struct slab_rcu *)head; 1810 struct kmem_cache *cachep = slab_rcu->cachep; 1811 1812 kmem_freepages(cachep, slab_rcu->addr); 1813 if (OFF_SLAB(cachep)) 1814 kmem_cache_free(cachep->slabp_cache, slab_rcu); 1815} 1816 1817#if DEBUG 1818 1819#ifdef CONFIG_DEBUG_PAGEALLOC 1820static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr, 1821 unsigned long caller) 1822{ 1823 int size = obj_size(cachep); 1824 1825 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)]; 1826 1827 if (size < 5 * sizeof(unsigned long)) 1828 return; 1829 1830 *addr++ = 0x12345678; 1831 *addr++ = caller; 1832 *addr++ = smp_processor_id(); 1833 size -= 3 * sizeof(unsigned long); 1834 { 1835 unsigned long *sptr = &caller; 1836 unsigned long svalue; 1837 1838 while (!kstack_end(sptr)) { 1839 svalue = *sptr++; 1840 if (kernel_text_address(svalue)) { 1841 *addr++ = svalue; 1842 size -= sizeof(unsigned long); 1843 if (size <= sizeof(unsigned long)) 1844 break; 1845 } 1846 } 1847 1848 } 1849 *addr++ = 0x87654321; 1850} 1851#endif 1852 1853static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val) 1854{ 1855 int size = obj_size(cachep); 1856 addr = &((char *)addr)[obj_offset(cachep)]; 1857 1858 memset(addr, val, size); 1859 *(unsigned char *)(addr + size - 1) = POISON_END; 1860} 1861 1862static void dump_line(char *data, int offset, int limit) 1863{ 1864 int i; 1865 unsigned char error = 0; 1866 int bad_count = 0; 1867 1868 printk(KERN_ERR "%03x: ", offset); 1869 for (i = 0; i < limit; i++) { 1870 if (data[offset + i] != POISON_FREE) { 1871 error = data[offset + i]; 1872 bad_count++; 1873 } 1874 } 1875 print_hex_dump(KERN_CONT, "", 0, 16, 1, 1876 &data[offset], limit, 1); 1877 1878 if (bad_count == 1) { 1879 error ^= POISON_FREE; 1880 if (!(error & (error - 1))) { 1881 printk(KERN_ERR "Single bit error detected. Probably " 1882 "bad RAM.\n"); 1883#ifdef CONFIG_X86 1884 printk(KERN_ERR "Run memtest86+ or a similar memory " 1885 "test tool.\n"); 1886#else 1887 printk(KERN_ERR "Run a memory test tool.\n"); 1888#endif 1889 } 1890 } 1891} 1892#endif 1893 1894#if DEBUG 1895 1896static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines) 1897{ 1898 int i, size; 1899 char *realobj; 1900 1901 if (cachep->flags & SLAB_RED_ZONE) { 1902 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n", 1903 *dbg_redzone1(cachep, objp), 1904 *dbg_redzone2(cachep, objp)); 1905 } 1906 1907 if (cachep->flags & SLAB_STORE_USER) { 1908 printk(KERN_ERR "Last user: [<%p>]", 1909 *dbg_userword(cachep, objp)); 1910 print_symbol("(%s)", 1911 (unsigned long)*dbg_userword(cachep, objp)); 1912 printk("\n"); 1913 } 1914 realobj = (char *)objp + obj_offset(cachep); 1915 size = obj_size(cachep); 1916 for (i = 0; i < size && lines; i += 16, lines--) { 1917 int limit; 1918 limit = 16; 1919 if (i + limit > size) 1920 limit = size - i; 1921 dump_line(realobj, i, limit); 1922 } 1923} 1924 1925static void check_poison_obj(struct kmem_cache *cachep, void *objp) 1926{ 1927 char *realobj; 1928 int size, i; 1929 int lines = 0; 1930 1931 realobj = (char *)objp + obj_offset(cachep); 1932 size = obj_size(cachep); 1933 1934 for (i = 0; i < size; i++) { 1935 char exp = POISON_FREE; 1936 if (i == size - 1) 1937 exp = POISON_END; 1938 if (realobj[i] != exp) { 1939 int limit; 1940 /* Mismatch ! */ 1941 /* Print header */ 1942 if (lines == 0) { 1943 printk(KERN_ERR 1944 "Slab corruption (%s): %s start=%p, len=%d\n", 1945 print_tainted(), cachep->name, realobj, size); 1946 print_objinfo(cachep, objp, 0); 1947 } 1948 /* Hexdump the affected line */ 1949 i = (i / 16) * 16; 1950 limit = 16; 1951 if (i + limit > size) 1952 limit = size - i; 1953 dump_line(realobj, i, limit); 1954 i += 16; 1955 lines++; 1956 /* Limit to 5 lines */ 1957 if (lines > 5) 1958 break; 1959 } 1960 } 1961 if (lines != 0) { 1962 /* Print some data about the neighboring objects, if they 1963 * exist: 1964 */ 1965 struct slab *slabp = virt_to_slab(objp); 1966 unsigned int objnr; 1967 1968 objnr = obj_to_index(cachep, slabp, objp); 1969 if (objnr) { 1970 objp = index_to_obj(cachep, slabp, objnr - 1); 1971 realobj = (char *)objp + obj_offset(cachep); 1972 printk(KERN_ERR "Prev obj: start=%p, len=%d\n", 1973 realobj, size); 1974 print_objinfo(cachep, objp, 2); 1975 } 1976 if (objnr + 1 < cachep->num) { 1977 objp = index_to_obj(cachep, slabp, objnr + 1); 1978 realobj = (char *)objp + obj_offset(cachep); 1979 printk(KERN_ERR "Next obj: start=%p, len=%d\n", 1980 realobj, size); 1981 print_objinfo(cachep, objp, 2); 1982 } 1983 } 1984} 1985#endif 1986 1987#if DEBUG 1988static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp) 1989{ 1990 int i; 1991 for (i = 0; i < cachep->num; i++) { 1992 void *objp = index_to_obj(cachep, slabp, i); 1993 1994 if (cachep->flags & SLAB_POISON) { 1995#ifdef CONFIG_DEBUG_PAGEALLOC 1996 if (cachep->buffer_size % PAGE_SIZE == 0 && 1997 OFF_SLAB(cachep)) 1998 kernel_map_pages(virt_to_page(objp), 1999 cachep->buffer_size / PAGE_SIZE, 1); 2000 else 2001 check_poison_obj(cachep, objp); 2002#else 2003 check_poison_obj(cachep, objp); 2004#endif 2005 } 2006 if (cachep->flags & SLAB_RED_ZONE) { 2007 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) 2008 slab_error(cachep, "start of a freed object " 2009 "was overwritten"); 2010 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) 2011 slab_error(cachep, "end of a freed object " 2012 "was overwritten"); 2013 } 2014 } 2015} 2016#else 2017static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp) 2018{ 2019} 2020#endif 2021 2022/** 2023 * slab_destroy - destroy and release all objects in a slab 2024 * @cachep: cache pointer being destroyed 2025 * @slabp: slab pointer being destroyed 2026 * 2027 * Destroy all the objs in a slab, and release the mem back to the system. 2028 * Before calling the slab must have been unlinked from the cache. The 2029 * cache-lock is not held/needed. 2030 */ 2031static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp) 2032{ 2033 void *addr = slabp->s_mem - slabp->colouroff; 2034 2035 slab_destroy_debugcheck(cachep, slabp); 2036 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) { 2037 struct slab_rcu *slab_rcu; 2038 2039 slab_rcu = (struct slab_rcu *)slabp; 2040 slab_rcu->cachep = cachep; 2041 slab_rcu->addr = addr; 2042 call_rcu(&slab_rcu->head, kmem_rcu_free); 2043 } else { 2044 kmem_freepages(cachep, addr); 2045 if (OFF_SLAB(cachep)) 2046 kmem_cache_free(cachep->slabp_cache, slabp); 2047 } 2048} 2049 2050static void __kmem_cache_destroy(struct kmem_cache *cachep) 2051{ 2052 int i; 2053 struct kmem_list3 *l3; 2054 2055 for_each_online_cpu(i) 2056 kfree(cachep->array[i]); 2057 2058 /* NUMA: free the list3 structures */ 2059 for_each_online_node(i) { 2060 l3 = cachep->nodelists[i]; 2061 if (l3) { 2062 kfree(l3->shared); 2063 free_alien_cache(l3->alien); 2064 kfree(l3); 2065 } 2066 } 2067 kmem_cache_free(&cache_cache, cachep); 2068} 2069 2070 2071/** 2072 * calculate_slab_order - calculate size (page order) of slabs 2073 * @cachep: pointer to the cache that is being created 2074 * @size: size of objects to be created in this cache. 2075 * @align: required alignment for the objects. 2076 * @flags: slab allocation flags 2077 * 2078 * Also calculates the number of objects per slab. 2079 * 2080 * This could be made much more intelligent. For now, try to avoid using 2081 * high order pages for slabs. When the gfp() functions are more friendly 2082 * towards high-order requests, this should be changed. 2083 */ 2084static size_t calculate_slab_order(struct kmem_cache *cachep, 2085 size_t size, size_t align, unsigned long flags) 2086{ 2087 unsigned long offslab_limit; 2088 size_t left_over = 0; 2089 int gfporder; 2090 2091 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) { 2092 unsigned int num; 2093 size_t remainder; 2094 2095 cache_estimate(gfporder, size, align, flags, &remainder, &num); 2096 if (!num) 2097 continue; 2098 2099 if (flags & CFLGS_OFF_SLAB) { 2100 /* 2101 * Max number of objs-per-slab for caches which 2102 * use off-slab slabs. Needed to avoid a possible 2103 * looping condition in cache_grow(). 2104 */ 2105 offslab_limit = size - sizeof(struct slab); 2106 offslab_limit /= sizeof(kmem_bufctl_t); 2107 2108 if (num > offslab_limit) 2109 break; 2110 } 2111 2112 /* Found something acceptable - save it away */ 2113 cachep->num = num; 2114 cachep->gfporder = gfporder; 2115 left_over = remainder; 2116 2117 /* 2118 * A VFS-reclaimable slab tends to have most allocations 2119 * as GFP_NOFS and we really don't want to have to be allocating 2120 * higher-order pages when we are unable to shrink dcache. 2121 */ 2122 if (flags & SLAB_RECLAIM_ACCOUNT) 2123 break; 2124 2125 /* 2126 * Large number of objects is good, but very large slabs are 2127 * currently bad for the gfp()s. 2128 */ 2129 if (gfporder >= slab_max_order) 2130 break; 2131 2132 /* 2133 * Acceptable internal fragmentation? 2134 */ 2135 if (left_over * 8 <= (PAGE_SIZE << gfporder)) 2136 break; 2137 } 2138 return left_over; 2139} 2140 2141static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) 2142{ 2143 if (g_cpucache_up == FULL) 2144 return enable_cpucache(cachep, gfp); 2145 2146 if (g_cpucache_up == NONE) { 2147 /* 2148 * Note: the first kmem_cache_create must create the cache 2149 * that's used by kmalloc(24), otherwise the creation of 2150 * further caches will BUG(). 2151 */ 2152 cachep->array[smp_processor_id()] = &initarray_generic.cache; 2153 2154 /* 2155 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is 2156 * the first cache, then we need to set up all its list3s, 2157 * otherwise the creation of further caches will BUG(). 2158 */ 2159 set_up_list3s(cachep, SIZE_AC); 2160 if (INDEX_AC == INDEX_L3) 2161 g_cpucache_up = PARTIAL_L3; 2162 else 2163 g_cpucache_up = PARTIAL_AC; 2164 } else { 2165 cachep->array[smp_processor_id()] = 2166 kmalloc(sizeof(struct arraycache_init), gfp); 2167 2168 if (g_cpucache_up == PARTIAL_AC) { 2169 set_up_list3s(cachep, SIZE_L3); 2170 g_cpucache_up = PARTIAL_L3; 2171 } else { 2172 int node; 2173 for_each_online_node(node) { 2174 cachep->nodelists[node] = 2175 kmalloc_node(sizeof(struct kmem_list3), 2176 gfp, node); 2177 BUG_ON(!cachep->nodelists[node]); 2178 kmem_list3_init(cachep->nodelists[node]); 2179 } 2180 } 2181 } 2182 cachep->nodelists[numa_mem_id()]->next_reap = 2183 jiffies + REAPTIMEOUT_LIST3 + 2184 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 2185 2186 cpu_cache_get(cachep)->avail = 0; 2187 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES; 2188 cpu_cache_get(cachep)->batchcount = 1; 2189 cpu_cache_get(cachep)->touched = 0; 2190 cachep->batchcount = 1; 2191 cachep->limit = BOOT_CPUCACHE_ENTRIES; 2192 return 0; 2193} 2194 2195/** 2196 * kmem_cache_create - Create a cache. 2197 * @name: A string which is used in /proc/slabinfo to identify this cache. 2198 * @size: The size of objects to be created in this cache. 2199 * @align: The required alignment for the objects. 2200 * @flags: SLAB flags 2201 * @ctor: A constructor for the objects. 2202 * 2203 * Returns a ptr to the cache on success, NULL on failure. 2204 * Cannot be called within a int, but can be interrupted. 2205 * The @ctor is run when new pages are allocated by the cache. 2206 * 2207 * @name must be valid until the cache is destroyed. This implies that 2208 * the module calling this has to destroy the cache before getting unloaded. 2209 * 2210 * The flags are 2211 * 2212 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 2213 * to catch references to uninitialised memory. 2214 * 2215 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 2216 * for buffer overruns. 2217 * 2218 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 2219 * cacheline. This can be beneficial if you're counting cycles as closely 2220 * as davem. 2221 */ 2222struct kmem_cache * 2223kmem_cache_create (const char *name, size_t size, size_t align, 2224 unsigned long flags, void (*ctor)(void *)) 2225{ 2226 size_t left_over, slab_size, ralign; 2227 struct kmem_cache *cachep = NULL, *pc; 2228 gfp_t gfp; 2229 2230 /* 2231 * Sanity checks... these are all serious usage bugs. 2232 */ 2233 if (!name || in_interrupt() || (size < BYTES_PER_WORD) || 2234 size > KMALLOC_MAX_SIZE) { 2235 printk(KERN_ERR "%s: Early error in slab %s\n", __func__, 2236 name); 2237 BUG(); 2238 } 2239 2240 /* 2241 * We use cache_chain_mutex to ensure a consistent view of 2242 * cpu_online_mask as well. Please see cpuup_callback 2243 */ 2244 if (slab_is_available()) { 2245 get_online_cpus(); 2246 mutex_lock(&cache_chain_mutex); 2247 } 2248 2249 list_for_each_entry(pc, &cache_chain, next) { 2250 char tmp; 2251 int res; 2252 2253 /* 2254 * This happens when the module gets unloaded and doesn't 2255 * destroy its slab cache and no-one else reuses the vmalloc 2256 * area of the module. Print a warning. 2257 */ 2258 res = probe_kernel_address(pc->name, tmp); 2259 if (res) { 2260 printk(KERN_ERR 2261 "SLAB: cache with size %d has lost its name\n", 2262 pc->buffer_size); 2263 continue; 2264 } 2265 2266 if (!strcmp(pc->name, name)) { 2267 printk(KERN_ERR 2268 "kmem_cache_create: duplicate cache %s\n", name); 2269 dump_stack(); 2270 goto oops; 2271 } 2272 } 2273 2274#if DEBUG 2275 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 2276#if FORCED_DEBUG 2277 /* 2278 * Enable redzoning and last user accounting, except for caches with 2279 * large objects, if the increased size would increase the object size 2280 * above the next power of two: caches with object sizes just above a 2281 * power of two have a significant amount of internal fragmentation. 2282 */ 2283 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN + 2284 2 * sizeof(unsigned long long))) 2285 flags |= SLAB_RED_ZONE | SLAB_STORE_USER; 2286 if (!(flags & SLAB_DESTROY_BY_RCU)) 2287 flags |= SLAB_POISON; 2288#endif 2289 if (flags & SLAB_DESTROY_BY_RCU) 2290 BUG_ON(flags & SLAB_POISON); 2291#endif 2292 /* 2293 * Always checks flags, a caller might be expecting debug support which 2294 * isn't available. 2295 */ 2296 BUG_ON(flags & ~CREATE_MASK); 2297 2298 /* 2299 * Check that size is in terms of words. This is needed to avoid 2300 * unaligned accesses for some archs when redzoning is used, and makes 2301 * sure any on-slab bufctl's are also correctly aligned. 2302 */ 2303 if (size & (BYTES_PER_WORD - 1)) { 2304 size += (BYTES_PER_WORD - 1); 2305 size &= ~(BYTES_PER_WORD - 1); 2306 } 2307 2308 /* calculate the final buffer alignment: */ 2309 2310 /* 1) arch recommendation: can be overridden for debug */ 2311 if (flags & SLAB_HWCACHE_ALIGN) { 2312 /* 2313 * Default alignment: as specified by the arch code. Except if 2314 * an object is really small, then squeeze multiple objects into 2315 * one cacheline. 2316 */ 2317 ralign = cache_line_size(); 2318 while (size <= ralign / 2) 2319 ralign /= 2; 2320 } else { 2321 ralign = BYTES_PER_WORD; 2322 } 2323 2324 /* 2325 * Redzoning and user store require word alignment or possibly larger. 2326 * Note this will be overridden by architecture or caller mandated 2327 * alignment if either is greater than BYTES_PER_WORD. 2328 */ 2329 if (flags & SLAB_STORE_USER) 2330 ralign = BYTES_PER_WORD; 2331 2332 if (flags & SLAB_RED_ZONE) { 2333 ralign = REDZONE_ALIGN; 2334 /* If redzoning, ensure that the second redzone is suitably 2335 * aligned, by adjusting the object size accordingly. */ 2336 size += REDZONE_ALIGN - 1; 2337 size &= ~(REDZONE_ALIGN - 1); 2338 } 2339 2340 /* 2) arch mandated alignment */ 2341 if (ralign < ARCH_SLAB_MINALIGN) { 2342 ralign = ARCH_SLAB_MINALIGN; 2343 } 2344 /* 3) caller mandated alignment */ 2345 if (ralign < align) { 2346 ralign = align; 2347 } 2348 /* disable debug if necessary */ 2349 if (ralign > __alignof__(unsigned long long)) 2350 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); 2351 /* 2352 * 4) Store it. 2353 */ 2354 align = ralign; 2355 2356 if (slab_is_available()) 2357 gfp = GFP_KERNEL; 2358 else 2359 gfp = GFP_NOWAIT; 2360 2361 /* Get cache's description obj. */ 2362 cachep = kmem_cache_zalloc(&cache_cache, gfp); 2363 if (!cachep) 2364 goto oops; 2365 2366 cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids]; 2367#if DEBUG 2368 cachep->obj_size = size; 2369 2370 /* 2371 * Both debugging options require word-alignment which is calculated 2372 * into align above. 2373 */ 2374 if (flags & SLAB_RED_ZONE) { 2375 /* add space for red zone words */ 2376 cachep->obj_offset += sizeof(unsigned long long); 2377 size += 2 * sizeof(unsigned long long); 2378 } 2379 if (flags & SLAB_STORE_USER) { 2380 /* user store requires one word storage behind the end of 2381 * the real object. But if the second red zone needs to be 2382 * aligned to 64 bits, we must allow that much space. 2383 */ 2384 if (flags & SLAB_RED_ZONE) 2385 size += REDZONE_ALIGN; 2386 else 2387 size += BYTES_PER_WORD; 2388 } 2389#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC) 2390 if (size >= malloc_sizes[INDEX_L3 + 1].cs_size 2391 && cachep->obj_size > cache_line_size() && ALIGN(size, align) < PAGE_SIZE) { 2392 cachep->obj_offset += PAGE_SIZE - ALIGN(size, align); 2393 size = PAGE_SIZE; 2394 } 2395#endif 2396#endif 2397 2398 /* 2399 * Determine if the slab management is 'on' or 'off' slab. 2400 * (bootstrapping cannot cope with offslab caches so don't do 2401 * it too early on. Always use on-slab management when 2402 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak) 2403 */ 2404 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init && 2405 !(flags & SLAB_NOLEAKTRACE)) 2406 /* 2407 * Size is large, assume best to place the slab management obj 2408 * off-slab (should allow better packing of objs). 2409 */ 2410 flags |= CFLGS_OFF_SLAB; 2411 2412 size = ALIGN(size, align); 2413 2414 left_over = calculate_slab_order(cachep, size, align, flags); 2415 2416 if (!cachep->num) { 2417 printk(KERN_ERR 2418 "kmem_cache_create: couldn't create cache %s.\n", name); 2419 kmem_cache_free(&cache_cache, cachep); 2420 cachep = NULL; 2421 goto oops; 2422 } 2423 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t) 2424 + sizeof(struct slab), align); 2425 2426 /* 2427 * If the slab has been placed off-slab, and we have enough space then 2428 * move it on-slab. This is at the expense of any extra colouring. 2429 */ 2430 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) { 2431 flags &= ~CFLGS_OFF_SLAB; 2432 left_over -= slab_size; 2433 } 2434 2435 if (flags & CFLGS_OFF_SLAB) { 2436 /* really off slab. No need for manual alignment */ 2437 slab_size = 2438 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab); 2439 2440#ifdef CONFIG_PAGE_POISONING 2441 /* If we're going to use the generic kernel_map_pages() 2442 * poisoning, then it's going to smash the contents of 2443 * the redzone and userword anyhow, so switch them off. 2444 */ 2445 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON) 2446 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); 2447#endif 2448 } 2449 2450 cachep->colour_off = cache_line_size(); 2451 /* Offset must be a multiple of the alignment. */ 2452 if (cachep->colour_off < align) 2453 cachep->colour_off = align; 2454 cachep->colour = left_over / cachep->colour_off; 2455 cachep->slab_size = slab_size; 2456 cachep->flags = flags; 2457 cachep->gfpflags = 0; 2458 if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA)) 2459 cachep->gfpflags |= GFP_DMA; 2460 cachep->buffer_size = size; 2461 cachep->reciprocal_buffer_size = reciprocal_value(size); 2462 2463 if (flags & CFLGS_OFF_SLAB) { 2464 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u); 2465 /* 2466 * This is a possibility for one of the malloc_sizes caches. 2467 * But since we go off slab only for object size greater than 2468 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order, 2469 * this should not happen at all. 2470 * But leave a BUG_ON for some lucky dude. 2471 */ 2472 BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache)); 2473 } 2474 cachep->ctor = ctor; 2475 cachep->name = name; 2476 2477 if (setup_cpu_cache(cachep, gfp)) { 2478 __kmem_cache_destroy(cachep); 2479 cachep = NULL; 2480 goto oops; 2481 } 2482 2483 if (flags & SLAB_DEBUG_OBJECTS) { 2484 /* 2485 * Would deadlock through slab_destroy()->call_rcu()-> 2486 * debug_object_activate()->kmem_cache_alloc(). 2487 */ 2488 WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU); 2489 2490 slab_set_debugobj_lock_classes(cachep); 2491 } 2492 2493 /* cache setup completed, link it into the list */ 2494 list_add(&cachep->next, &cache_chain); 2495oops: 2496 if (!cachep && (flags & SLAB_PANIC)) 2497 panic("kmem_cache_create(): failed to create slab `%s'\n", 2498 name); 2499 if (slab_is_available()) { 2500 mutex_unlock(&cache_chain_mutex); 2501 put_online_cpus(); 2502 } 2503 return cachep; 2504} 2505EXPORT_SYMBOL(kmem_cache_create); 2506 2507#if DEBUG 2508static void check_irq_off(void) 2509{ 2510 BUG_ON(!irqs_disabled()); 2511} 2512 2513static void check_irq_on(void) 2514{ 2515 BUG_ON(irqs_disabled()); 2516} 2517 2518static void check_spinlock_acquired(struct kmem_cache *cachep) 2519{ 2520#ifdef CONFIG_SMP 2521 check_irq_off(); 2522 assert_spin_locked(&cachep->nodelists[numa_mem_id()]->list_lock); 2523#endif 2524} 2525 2526static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) 2527{ 2528#ifdef CONFIG_SMP 2529 check_irq_off(); 2530 assert_spin_locked(&cachep->nodelists[node]->list_lock); 2531#endif 2532} 2533 2534#else 2535#define check_irq_off() do { } while(0) 2536#define check_irq_on() do { } while(0) 2537#define check_spinlock_acquired(x) do { } while(0) 2538#define check_spinlock_acquired_node(x, y) do { } while(0) 2539#endif 2540 2541static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3, 2542 struct array_cache *ac, 2543 int force, int node); 2544 2545static void do_drain(void *arg) 2546{ 2547 struct kmem_cache *cachep = arg; 2548 struct array_cache *ac; 2549 int node = numa_mem_id(); 2550 2551 check_irq_off(); 2552 ac = cpu_cache_get(cachep); 2553 spin_lock(&cachep->nodelists[node]->list_lock); 2554 free_block(cachep, ac->entry, ac->avail, node); 2555 spin_unlock(&cachep->nodelists[node]->list_lock); 2556 ac->avail = 0; 2557} 2558 2559static void drain_cpu_caches(struct kmem_cache *cachep) 2560{ 2561 struct kmem_list3 *l3; 2562 int node; 2563 2564 on_each_cpu(do_drain, cachep, 1); 2565 check_irq_on(); 2566 for_each_online_node(node) { 2567 l3 = cachep->nodelists[node]; 2568 if (l3 && l3->alien) 2569 drain_alien_cache(cachep, l3->alien); 2570 } 2571 2572 for_each_online_node(node) { 2573 l3 = cachep->nodelists[node]; 2574 if (l3) 2575 drain_array(cachep, l3, l3->shared, 1, node); 2576 } 2577} 2578 2579/* 2580 * Remove slabs from the list of free slabs. 2581 * Specify the number of slabs to drain in tofree. 2582 * 2583 * Returns the actual number of slabs released. 2584 */ 2585static int drain_freelist(struct kmem_cache *cache, 2586 struct kmem_list3 *l3, int tofree) 2587{ 2588 struct list_head *p; 2589 int nr_freed; 2590 struct slab *slabp; 2591 2592 nr_freed = 0; 2593 while (nr_freed < tofree && !list_empty(&l3->slabs_free)) { 2594 2595 spin_lock_irq(&l3->list_lock); 2596 p = l3->slabs_free.prev; 2597 if (p == &l3->slabs_free) { 2598 spin_unlock_irq(&l3->list_lock); 2599 goto out; 2600 } 2601 2602 slabp = list_entry(p, struct slab, list); 2603#if DEBUG 2604 BUG_ON(slabp->inuse); 2605#endif 2606 list_del(&slabp->list); 2607 /* 2608 * Safe to drop the lock. The slab is no longer linked 2609 * to the cache. 2610 */ 2611 l3->free_objects -= cache->num; 2612 spin_unlock_irq(&l3->list_lock); 2613 slab_destroy(cache, slabp); 2614 nr_freed++; 2615 } 2616out: 2617 return nr_freed; 2618} 2619 2620/* Called with cache_chain_mutex held to protect against cpu hotplug */ 2621static int __cache_shrink(struct kmem_cache *cachep) 2622{ 2623 int ret = 0, i = 0; 2624 struct kmem_list3 *l3; 2625 2626 drain_cpu_caches(cachep); 2627 2628 check_irq_on(); 2629 for_each_online_node(i) { 2630 l3 = cachep->nodelists[i]; 2631 if (!l3) 2632 continue; 2633 2634 drain_freelist(cachep, l3, l3->free_objects); 2635 2636 ret += !list_empty(&l3->slabs_full) || 2637 !list_empty(&l3->slabs_partial); 2638 } 2639 return (ret ? 1 : 0); 2640} 2641 2642/** 2643 * kmem_cache_shrink - Shrink a cache. 2644 * @cachep: The cache to shrink. 2645 * 2646 * Releases as many slabs as possible for a cache. 2647 * To help debugging, a zero exit status indicates all slabs were released. 2648 */ 2649int kmem_cache_shrink(struct kmem_cache *cachep) 2650{ 2651 int ret; 2652 BUG_ON(!cachep || in_interrupt()); 2653 2654 get_online_cpus(); 2655 mutex_lock(&cache_chain_mutex); 2656 ret = __cache_shrink(cachep); 2657 mutex_unlock(&cache_chain_mutex); 2658 put_online_cpus(); 2659 return ret; 2660} 2661EXPORT_SYMBOL(kmem_cache_shrink); 2662 2663/** 2664 * kmem_cache_destroy - delete a cache 2665 * @cachep: the cache to destroy 2666 * 2667 * Remove a &struct kmem_cache object from the slab cache. 2668 * 2669 * It is expected this function will be called by a module when it is 2670 * unloaded. This will remove the cache completely, and avoid a duplicate 2671 * cache being allocated each time a module is loaded and unloaded, if the 2672 * module doesn't have persistent in-kernel storage across loads and unloads. 2673 * 2674 * The cache must be empty before calling this function. 2675 * 2676 * The caller must guarantee that no one will allocate memory from the cache 2677 * during the kmem_cache_destroy(). 2678 */ 2679void kmem_cache_destroy(struct kmem_cache *cachep) 2680{ 2681 BUG_ON(!cachep || in_interrupt()); 2682 2683 /* Find the cache in the chain of caches. */ 2684 get_online_cpus(); 2685 mutex_lock(&cache_chain_mutex); 2686 /* 2687 * the chain is never empty, cache_cache is never destroyed 2688 */ 2689 list_del(&cachep->next); 2690 if (__cache_shrink(cachep)) { 2691 slab_error(cachep, "Can't free all objects"); 2692 list_add(&cachep->next, &cache_chain); 2693 mutex_unlock(&cache_chain_mutex); 2694 put_online_cpus(); 2695 return; 2696 } 2697 2698 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) 2699 rcu_barrier(); 2700 2701 __kmem_cache_destroy(cachep); 2702 mutex_unlock(&cache_chain_mutex); 2703 put_online_cpus(); 2704} 2705EXPORT_SYMBOL(kmem_cache_destroy); 2706 2707/* 2708 * Get the memory for a slab management obj. 2709 * For a slab cache when the slab descriptor is off-slab, slab descriptors 2710 * always come from malloc_sizes caches. The slab descriptor cannot 2711 * come from the same cache which is getting created because, 2712 * when we are searching for an appropriate cache for these 2713 * descriptors in kmem_cache_create, we search through the malloc_sizes array. 2714 * If we are creating a malloc_sizes cache here it would not be visible to 2715 * kmem_find_general_cachep till the initialization is complete. 2716 * Hence we cannot have slabp_cache same as the original cache. 2717 */ 2718static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp, 2719 int colour_off, gfp_t local_flags, 2720 int nodeid) 2721{ 2722 struct slab *slabp; 2723 2724 if (OFF_SLAB(cachep)) { 2725 /* Slab management obj is off-slab. */ 2726 slabp = kmem_cache_alloc_node(cachep->slabp_cache, 2727 local_flags, nodeid); 2728 /* 2729 * If the first object in the slab is leaked (it's allocated 2730 * but no one has a reference to it), we want to make sure 2731 * kmemleak does not treat the ->s_mem pointer as a reference 2732 * to the object. Otherwise we will not report the leak. 2733 */ 2734 kmemleak_scan_area(&slabp->list, sizeof(struct list_head), 2735 local_flags); 2736 if (!slabp) 2737 return NULL; 2738 } else { 2739 slabp = objp + colour_off; 2740 colour_off += cachep->slab_size; 2741 } 2742 slabp->inuse = 0; 2743 slabp->colouroff = colour_off; 2744 slabp->s_mem = objp + colour_off; 2745 slabp->nodeid = nodeid; 2746 slabp->free = 0; 2747 return slabp; 2748} 2749 2750static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp) 2751{ 2752 return (kmem_bufctl_t *) (slabp + 1); 2753} 2754 2755static void cache_init_objs(struct kmem_cache *cachep, 2756 struct slab *slabp) 2757{ 2758 int i; 2759 2760 for (i = 0; i < cachep->num; i++) { 2761 void *objp = index_to_obj(cachep, slabp, i); 2762#if DEBUG 2763 /* need to poison the objs? */ 2764 if (cachep->flags & SLAB_POISON) 2765 poison_obj(cachep, objp, POISON_FREE); 2766 if (cachep->flags & SLAB_STORE_USER) 2767 *dbg_userword(cachep, objp) = NULL; 2768 2769 if (cachep->flags & SLAB_RED_ZONE) { 2770 *dbg_redzone1(cachep, objp) = RED_INACTIVE; 2771 *dbg_redzone2(cachep, objp) = RED_INACTIVE; 2772 } 2773 /* 2774 * Constructors are not allowed to allocate memory from the same 2775 * cache which they are a constructor for. Otherwise, deadlock. 2776 * They must also be threaded. 2777 */ 2778 if (cachep->ctor && !(cachep->flags & SLAB_POISON)) 2779 cachep->ctor(objp + obj_offset(cachep)); 2780 2781 if (cachep->flags & SLAB_RED_ZONE) { 2782 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) 2783 slab_error(cachep, "constructor overwrote the" 2784 " end of an object"); 2785 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) 2786 slab_error(cachep, "constructor overwrote the" 2787 " start of an object"); 2788 } 2789 if ((cachep->buffer_size % PAGE_SIZE) == 0 && 2790 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON) 2791 kernel_map_pages(virt_to_page(objp), 2792 cachep->buffer_size / PAGE_SIZE, 0); 2793#else 2794 if (cachep->ctor) 2795 cachep->ctor(objp); 2796#endif 2797 slab_bufctl(slabp)[i] = i + 1; 2798 } 2799 slab_bufctl(slabp)[i - 1] = BUFCTL_END; 2800} 2801 2802static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) 2803{ 2804 if (CONFIG_ZONE_DMA_FLAG) { 2805 if (flags & GFP_DMA) 2806 BUG_ON(!(cachep->gfpflags & GFP_DMA)); 2807 else 2808 BUG_ON(cachep->gfpflags & GFP_DMA); 2809 } 2810} 2811 2812static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp, 2813 int nodeid) 2814{ 2815 void *objp = index_to_obj(cachep, slabp, slabp->free); 2816 kmem_bufctl_t next; 2817 2818 slabp->inuse++; 2819 next = slab_bufctl(slabp)[slabp->free]; 2820#if DEBUG 2821 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE; 2822 WARN_ON(slabp->nodeid != nodeid); 2823#endif 2824 slabp->free = next; 2825 2826 return objp; 2827} 2828 2829static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, 2830 void *objp, int nodeid) 2831{ 2832 unsigned int objnr = obj_to_index(cachep, slabp, objp); 2833 2834#if DEBUG 2835 /* Verify that the slab belongs to the intended node */ 2836 WARN_ON(slabp->nodeid != nodeid); 2837 2838 if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) { 2839 printk(KERN_ERR "slab: double free detected in cache " 2840 "'%s', objp %p\n", cachep->name, objp); 2841 BUG(); 2842 } 2843#endif 2844 slab_bufctl(slabp)[objnr] = slabp->free; 2845 slabp->free = objnr; 2846 slabp->inuse--; 2847} 2848 2849/* 2850 * Map pages beginning at addr to the given cache and slab. This is required 2851 * for the slab allocator to be able to lookup the cache and slab of a 2852 * virtual address for kfree, ksize, and slab debugging. 2853 */ 2854static void slab_map_pages(struct kmem_cache *cache, struct slab *slab, 2855 void *addr) 2856{ 2857 int nr_pages; 2858 struct page *page; 2859 2860 page = virt_to_page(addr); 2861 2862 nr_pages = 1; 2863 if (likely(!PageCompound(page))) 2864 nr_pages <<= cache->gfporder; 2865 2866 do { 2867 page_set_cache(page, cache); 2868 page_set_slab(page, slab); 2869 page++; 2870 } while (--nr_pages); 2871} 2872 2873/* 2874 * Grow (by 1) the number of slabs within a cache. This is called by 2875 * kmem_cache_alloc() when there are no active objs left in a cache. 2876 */ 2877static int cache_grow(struct kmem_cache *cachep, 2878 gfp_t flags, int nodeid, void *objp) 2879{ 2880 struct slab *slabp; 2881 size_t offset; 2882 gfp_t local_flags; 2883 struct kmem_list3 *l3; 2884 2885 /* 2886 * Be lazy and only check for valid flags here, keeping it out of the 2887 * critical path in kmem_cache_alloc(). 2888 */ 2889 BUG_ON(flags & GFP_SLAB_BUG_MASK); 2890 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); 2891 2892 /* Take the l3 list lock to change the colour_next on this node */ 2893 check_irq_off(); 2894 l3 = cachep->nodelists[nodeid]; 2895 spin_lock(&l3->list_lock); 2896 2897 /* Get colour for the slab, and cal the next value. */ 2898 offset = l3->colour_next; 2899 l3->colour_next++; 2900 if (l3->colour_next >= cachep->colour) 2901 l3->colour_next = 0; 2902 spin_unlock(&l3->list_lock); 2903 2904 offset *= cachep->colour_off; 2905 2906 if (local_flags & __GFP_WAIT) 2907 local_irq_enable(); 2908 2909 /* 2910 * The test for missing atomic flag is performed here, rather than 2911 * the more obvious place, simply to reduce the critical path length 2912 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they 2913 * will eventually be caught here (where it matters). 2914 */ 2915 kmem_flagcheck(cachep, flags); 2916 2917 /* 2918 * Get mem for the objs. Attempt to allocate a physical page from 2919 * 'nodeid'. 2920 */ 2921 if (!objp) 2922 objp = kmem_getpages(cachep, local_flags, nodeid); 2923 if (!objp) 2924 goto failed; 2925 2926 /* Get slab management. */ 2927 slabp = alloc_slabmgmt(cachep, objp, offset, 2928 local_flags & ~GFP_CONSTRAINT_MASK, nodeid); 2929 if (!slabp) 2930 goto opps1; 2931 2932 slab_map_pages(cachep, slabp, objp); 2933 2934 cache_init_objs(cachep, slabp); 2935 2936 if (local_flags & __GFP_WAIT) 2937 local_irq_disable(); 2938 check_irq_off(); 2939 spin_lock(&l3->list_lock); 2940 2941 /* Make slab active. */ 2942 list_add_tail(&slabp->list, &(l3->slabs_free)); 2943 STATS_INC_GROWN(cachep); 2944 l3->free_objects += cachep->num; 2945 spin_unlock(&l3->list_lock); 2946 return 1; 2947opps1: 2948 kmem_freepages(cachep, objp); 2949failed: 2950 if (local_flags & __GFP_WAIT) 2951 local_irq_disable(); 2952 return 0; 2953} 2954 2955#if DEBUG 2956 2957/* 2958 * Perform extra freeing checks: 2959 * - detect bad pointers. 2960 * - POISON/RED_ZONE checking 2961 */ 2962static void kfree_debugcheck(const void *objp) 2963{ 2964 if (!virt_addr_valid(objp)) { 2965 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n", 2966 (unsigned long)objp); 2967 BUG(); 2968 } 2969} 2970 2971static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) 2972{ 2973 unsigned long long redzone1, redzone2; 2974 2975 redzone1 = *dbg_redzone1(cache, obj); 2976 redzone2 = *dbg_redzone2(cache, obj); 2977 2978 /* 2979 * Redzone is ok. 2980 */ 2981 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE) 2982 return; 2983 2984 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE) 2985 slab_error(cache, "double free detected"); 2986 else 2987 slab_error(cache, "memory outside object was overwritten"); 2988 2989 printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n", 2990 obj, redzone1, redzone2); 2991} 2992 2993static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, 2994 void *caller) 2995{ 2996 struct page *page; 2997 unsigned int objnr; 2998 struct slab *slabp; 2999 3000 BUG_ON(virt_to_cache(objp) != cachep); 3001 3002 objp -= obj_offset(cachep); 3003 kfree_debugcheck(objp); 3004 page = virt_to_head_page(objp); 3005 3006 slabp = page_get_slab(page); 3007 3008 if (cachep->flags & SLAB_RED_ZONE) { 3009 verify_redzone_free(cachep, objp); 3010 *dbg_redzone1(cachep, objp) = RED_INACTIVE; 3011 *dbg_redzone2(cachep, objp) = RED_INACTIVE; 3012 } 3013 if (cachep->flags & SLAB_STORE_USER) 3014 *dbg_userword(cachep, objp) = caller; 3015 3016 objnr = obj_to_index(cachep, slabp, objp); 3017 3018 BUG_ON(objnr >= cachep->num); 3019 BUG_ON(objp != index_to_obj(cachep, slabp, objnr)); 3020 3021#ifdef CONFIG_DEBUG_SLAB_LEAK 3022 slab_bufctl(slabp)[objnr] = BUFCTL_FREE; 3023#endif 3024 if (cachep->flags & SLAB_POISON) { 3025#ifdef CONFIG_DEBUG_PAGEALLOC 3026 if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) { 3027 store_stackinfo(cachep, objp, (unsigned long)caller); 3028 kernel_map_pages(virt_to_page(objp), 3029 cachep->buffer_size / PAGE_SIZE, 0); 3030 } else { 3031 poison_obj(cachep, objp, POISON_FREE); 3032 } 3033#else 3034 poison_obj(cachep, objp, POISON_FREE); 3035#endif 3036 } 3037 return objp; 3038} 3039 3040static void check_slabp(struct kmem_cache *cachep, struct slab *slabp) 3041{ 3042 kmem_bufctl_t i; 3043 int entries = 0; 3044 3045 /* Check slab's freelist to see if this obj is there. */ 3046 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) { 3047 entries++; 3048 if (entries > cachep->num || i >= cachep->num) 3049 goto bad; 3050 } 3051 if (entries != cachep->num - slabp->inuse) { 3052bad: 3053 printk(KERN_ERR "slab: Internal list corruption detected in " 3054 "cache '%s'(%d), slabp %p(%d). Tainted(%s). Hexdump:\n", 3055 cachep->name, cachep->num, slabp, slabp->inuse, 3056 print_tainted()); 3057 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp, 3058 sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t), 3059 1); 3060 BUG(); 3061 } 3062} 3063#else 3064#define kfree_debugcheck(x) do { } while(0) 3065#define cache_free_debugcheck(x,objp,z) (objp) 3066#define check_slabp(x,y) do { } while(0) 3067#endif 3068 3069static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) 3070{ 3071 int batchcount; 3072 struct kmem_list3 *l3; 3073 struct array_cache *ac; 3074 int node; 3075 3076retry: 3077 check_irq_off(); 3078 node = numa_mem_id(); 3079 ac = cpu_cache_get(cachep); 3080 batchcount = ac->batchcount; 3081 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { 3082 /* 3083 * If there was little recent activity on this cache, then 3084 * perform only a partial refill. Otherwise we could generate 3085 * refill bouncing. 3086 */ 3087 batchcount = BATCHREFILL_LIMIT; 3088 } 3089 l3 = cachep->nodelists[node]; 3090 3091 BUG_ON(ac->avail > 0 || !l3); 3092 spin_lock(&l3->list_lock); 3093 3094 /* See if we can refill from the shared array */ 3095 if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) { 3096 l3->shared->touched = 1; 3097 goto alloc_done; 3098 } 3099 3100 while (batchcount > 0) { 3101 struct list_head *entry; 3102 struct slab *slabp; 3103 /* Get slab alloc is to come from. */ 3104 entry = l3->slabs_partial.next; 3105 if (entry == &l3->slabs_partial) { 3106 l3->free_touched = 1; 3107 entry = l3->slabs_free.next; 3108 if (entry == &l3->slabs_free) 3109 goto must_grow; 3110 } 3111 3112 slabp = list_entry(entry, struct slab, list); 3113 check_slabp(cachep, slabp); 3114 check_spinlock_acquired(cachep); 3115 3116 /* 3117 * The slab was either on partial or free list so 3118 * there must be at least one object available for 3119 * allocation. 3120 */ 3121 BUG_ON(slabp->inuse >= cachep->num); 3122 3123 while (slabp->inuse < cachep->num && batchcount--) { 3124 STATS_INC_ALLOCED(cachep); 3125 STATS_INC_ACTIVE(cachep); 3126 STATS_SET_HIGH(cachep); 3127 3128 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp, 3129 node); 3130 } 3131 check_slabp(cachep, slabp); 3132 3133 /* move slabp to correct slabp list: */ 3134 list_del(&slabp->list); 3135 if (slabp->free == BUFCTL_END) 3136 list_add(&slabp->list, &l3->slabs_full); 3137 else 3138 list_add(&slabp->list, &l3->slabs_partial); 3139 } 3140 3141must_grow: 3142 l3->free_objects -= ac->avail; 3143alloc_done: 3144 spin_unlock(&l3->list_lock); 3145 3146 if (unlikely(!ac->avail)) { 3147 int x; 3148 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL); 3149 3150 /* cache_grow can reenable interrupts, then ac could change. */ 3151 ac = cpu_cache_get(cachep); 3152 if (!x && ac->avail == 0) /* no objects in sight? abort */ 3153 return NULL; 3154 3155 if (!ac->avail) /* objects refilled by interrupt? */ 3156 goto retry; 3157 } 3158 ac->touched = 1; 3159 return ac->entry[--ac->avail]; 3160} 3161 3162static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, 3163 gfp_t flags) 3164{ 3165 might_sleep_if(flags & __GFP_WAIT); 3166#if DEBUG 3167 kmem_flagcheck(cachep, flags); 3168#endif 3169} 3170 3171#if DEBUG 3172static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, 3173 gfp_t flags, void *objp, void *caller) 3174{ 3175 if (!objp) 3176 return objp; 3177 if (cachep->flags & SLAB_POISON) { 3178#ifdef CONFIG_DEBUG_PAGEALLOC 3179 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) 3180 kernel_map_pages(virt_to_page(objp), 3181 cachep->buffer_size / PAGE_SIZE, 1); 3182 else 3183 check_poison_obj(cachep, objp); 3184#else 3185 check_poison_obj(cachep, objp); 3186#endif 3187 poison_obj(cachep, objp, POISON_INUSE); 3188 } 3189 if (cachep->flags & SLAB_STORE_USER) 3190 *dbg_userword(cachep, objp) = caller; 3191 3192 if (cachep->flags & SLAB_RED_ZONE) { 3193 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || 3194 *dbg_redzone2(cachep, objp) != RED_INACTIVE) { 3195 slab_error(cachep, "double free, or memory outside" 3196 " object was overwritten"); 3197 printk(KERN_ERR 3198 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n", 3199 objp, *dbg_redzone1(cachep, objp), 3200 *dbg_redzone2(cachep, objp)); 3201 } 3202 *dbg_redzone1(cachep, objp) = RED_ACTIVE; 3203 *dbg_redzone2(cachep, objp) = RED_ACTIVE; 3204 } 3205#ifdef CONFIG_DEBUG_SLAB_LEAK 3206 { 3207 struct slab *slabp; 3208 unsigned objnr; 3209 3210 slabp = page_get_slab(virt_to_head_page(objp)); 3211 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size; 3212 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE; 3213 } 3214#endif 3215 objp += obj_offset(cachep); 3216 if (cachep->ctor && cachep->flags & SLAB_POISON) 3217 cachep->ctor(objp); 3218 if (ARCH_SLAB_MINALIGN && 3219 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) { 3220 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n", 3221 objp, (int)ARCH_SLAB_MINALIGN); 3222 } 3223 return objp; 3224} 3225#else 3226#define cache_alloc_debugcheck_after(a,b,objp,d) (objp) 3227#endif 3228 3229static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags) 3230{ 3231 if (cachep == &cache_cache) 3232 return false; 3233 3234 return should_failslab(obj_size(cachep), flags, cachep->flags); 3235} 3236 3237static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3238{ 3239 void *objp; 3240 struct array_cache *ac; 3241 3242 check_irq_off(); 3243 3244 ac = cpu_cache_get(cachep); 3245 if (likely(ac->avail)) { 3246 STATS_INC_ALLOCHIT(cachep); 3247 ac->touched = 1; 3248 objp = ac->entry[--ac->avail]; 3249 } else { 3250 STATS_INC_ALLOCMISS(cachep); 3251 objp = cache_alloc_refill(cachep, flags); 3252 /* 3253 * the 'ac' may be updated by cache_alloc_refill(), 3254 * and kmemleak_erase() requires its correct value. 3255 */ 3256 ac = cpu_cache_get(cachep); 3257 } 3258 /* 3259 * To avoid a false negative, if an object that is in one of the 3260 * per-CPU caches is leaked, we need to make sure kmemleak doesn't 3261 * treat the array pointers as a reference to the object. 3262 */ 3263 if (objp) 3264 kmemleak_erase(&ac->entry[ac->avail]); 3265 return objp; 3266} 3267 3268#ifdef CONFIG_NUMA 3269/* 3270 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY. 3271 * 3272 * If we are in_interrupt, then process context, including cpusets and 3273 * mempolicy, may not apply and should not be used for allocation policy. 3274 */ 3275static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) 3276{ 3277 int nid_alloc, nid_here; 3278 3279 if (in_interrupt() || (flags & __GFP_THISNODE)) 3280 return NULL; 3281 nid_alloc = nid_here = numa_mem_id(); 3282 get_mems_allowed(); 3283 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) 3284 nid_alloc = cpuset_slab_spread_node(); 3285 else if (current->mempolicy) 3286 nid_alloc = slab_node(current->mempolicy); 3287 put_mems_allowed(); 3288 if (nid_alloc != nid_here) 3289 return ____cache_alloc_node(cachep, flags, nid_alloc); 3290 return NULL; 3291} 3292 3293/* 3294 * Fallback function if there was no memory available and no objects on a 3295 * certain node and fall back is permitted. First we scan all the 3296 * available nodelists for available objects. If that fails then we 3297 * perform an allocation without specifying a node. This allows the page 3298 * allocator to do its reclaim / fallback magic. We then insert the 3299 * slab into the proper nodelist and then allocate from it. 3300 */ 3301static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) 3302{ 3303 struct zonelist *zonelist; 3304 gfp_t local_flags; 3305 struct zoneref *z; 3306 struct zone *zone; 3307 enum zone_type high_zoneidx = gfp_zone(flags); 3308 void *obj = NULL; 3309 int nid; 3310 3311 if (flags & __GFP_THISNODE) 3312 return NULL; 3313 3314 get_mems_allowed(); 3315 zonelist = node_zonelist(slab_node(current->mempolicy), flags); 3316 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); 3317 3318retry: 3319 /* 3320 * Look through allowed nodes for objects available 3321 * from existing per node queues. 3322 */ 3323 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { 3324 nid = zone_to_nid(zone); 3325 3326 if (cpuset_zone_allowed_hardwall(zone, flags) && 3327 cache->nodelists[nid] && 3328 cache->nodelists[nid]->free_objects) { 3329 obj = ____cache_alloc_node(cache, 3330 flags | GFP_THISNODE, nid); 3331 if (obj) 3332 break; 3333 } 3334 } 3335 3336 if (!obj) { 3337 /* 3338 * This allocation will be performed within the constraints 3339 * of the current cpuset / memory policy requirements. 3340 * We may trigger various forms of reclaim on the allowed 3341 * set and go into memory reserves if necessary. 3342 */ 3343 if (local_flags & __GFP_WAIT) 3344 local_irq_enable(); 3345 kmem_flagcheck(cache, flags); 3346 obj = kmem_getpages(cache, local_flags, numa_mem_id()); 3347 if (local_flags & __GFP_WAIT) 3348 local_irq_disable(); 3349 if (obj) { 3350 /* 3351 * Insert into the appropriate per node queues 3352 */ 3353 nid = page_to_nid(virt_to_page(obj)); 3354 if (cache_grow(cache, flags, nid, obj)) { 3355 obj = ____cache_alloc_node(cache, 3356 flags | GFP_THISNODE, nid); 3357 if (!obj) 3358 /* 3359 * Another processor may allocate the 3360 * objects in the slab since we are 3361 * not holding any locks. 3362 */ 3363 goto retry; 3364 } else { 3365 /* cache_grow already freed obj */ 3366 obj = NULL; 3367 } 3368 } 3369 } 3370 put_mems_allowed(); 3371 return obj; 3372} 3373 3374/* 3375 * A interface to enable slab creation on nodeid 3376 */ 3377static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, 3378 int nodeid) 3379{ 3380 struct list_head *entry; 3381 struct slab *slabp; 3382 struct kmem_list3 *l3; 3383 void *obj; 3384 int x; 3385 3386 l3 = cachep->nodelists[nodeid]; 3387 BUG_ON(!l3); 3388 3389retry: 3390 check_irq_off(); 3391 spin_lock(&l3->list_lock); 3392 entry = l3->slabs_partial.next; 3393 if (entry == &l3->slabs_partial) { 3394 l3->free_touched = 1; 3395 entry = l3->slabs_free.next; 3396 if (entry == &l3->slabs_free) 3397 goto must_grow; 3398 } 3399 3400 slabp = list_entry(entry, struct slab, list); 3401 check_spinlock_acquired_node(cachep, nodeid); 3402 check_slabp(cachep, slabp); 3403 3404 STATS_INC_NODEALLOCS(cachep); 3405 STATS_INC_ACTIVE(cachep); 3406 STATS_SET_HIGH(cachep); 3407 3408 BUG_ON(slabp->inuse == cachep->num); 3409 3410 obj = slab_get_obj(cachep, slabp, nodeid); 3411 check_slabp(cachep, slabp); 3412 l3->free_objects--; 3413 /* move slabp to correct slabp list: */ 3414 list_del(&slabp->list); 3415 3416 if (slabp->free == BUFCTL_END) 3417 list_add(&slabp->list, &l3->slabs_full); 3418 else 3419 list_add(&slabp->list, &l3->slabs_partial); 3420 3421 spin_unlock(&l3->list_lock); 3422 goto done; 3423 3424must_grow: 3425 spin_unlock(&l3->list_lock); 3426 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL); 3427 if (x) 3428 goto retry; 3429 3430 return fallback_alloc(cachep, flags); 3431 3432done: 3433 return obj; 3434} 3435 3436/** 3437 * kmem_cache_alloc_node - Allocate an object on the specified node 3438 * @cachep: The cache to allocate from. 3439 * @flags: See kmalloc(). 3440 * @nodeid: node number of the target node. 3441 * @caller: return address of caller, used for debug information 3442 * 3443 * Identical to kmem_cache_alloc but it will allocate memory on the given 3444 * node, which can improve the performance for cpu bound structures. 3445 * 3446 * Fallback to other node is possible if __GFP_THISNODE is not set. 3447 */ 3448static __always_inline void * 3449__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, 3450 void *caller) 3451{ 3452 unsigned long save_flags; 3453 void *ptr; 3454 int slab_node = numa_mem_id(); 3455 3456 flags &= gfp_allowed_mask; 3457 3458 lockdep_trace_alloc(flags); 3459 3460 if (slab_should_failslab(cachep, flags)) 3461 return NULL; 3462 3463 cache_alloc_debugcheck_before(cachep, flags); 3464 local_irq_save(save_flags); 3465 3466 if (nodeid == NUMA_NO_NODE) 3467 nodeid = slab_node; 3468 3469 if (unlikely(!cachep->nodelists[nodeid])) { 3470 /* Node not bootstrapped yet */ 3471 ptr = fallback_alloc(cachep, flags); 3472 goto out; 3473 } 3474 3475 if (nodeid == slab_node) { 3476 /* 3477 * Use the locally cached objects if possible. 3478 * However ____cache_alloc does not allow fallback 3479 * to other nodes. It may fail while we still have 3480 * objects on other nodes available. 3481 */ 3482 ptr = ____cache_alloc(cachep, flags); 3483 if (ptr) 3484 goto out; 3485 } 3486 /* ___cache_alloc_node can fall back to other nodes */ 3487 ptr = ____cache_alloc_node(cachep, flags, nodeid); 3488 out: 3489 local_irq_restore(save_flags); 3490 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller); 3491 kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags, 3492 flags); 3493 3494 if (likely(ptr)) 3495 kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep)); 3496 3497 if (unlikely((flags & __GFP_ZERO) && ptr)) 3498 memset(ptr, 0, obj_size(cachep)); 3499 3500 return ptr; 3501} 3502 3503static __always_inline void * 3504__do_cache_alloc(struct kmem_cache *cache, gfp_t flags) 3505{ 3506 void *objp; 3507 3508 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) { 3509 objp = alternate_node_alloc(cache, flags); 3510 if (objp) 3511 goto out; 3512 } 3513 objp = ____cache_alloc(cache, flags); 3514 3515 /* 3516 * We may just have run out of memory on the local node. 3517 * ____cache_alloc_node() knows how to locate memory on other nodes 3518 */ 3519 if (!objp) 3520 objp = ____cache_alloc_node(cache, flags, numa_mem_id()); 3521 3522 out: 3523 return objp; 3524} 3525#else 3526 3527static __always_inline void * 3528__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3529{ 3530 return ____cache_alloc(cachep, flags); 3531} 3532 3533#endif /* CONFIG_NUMA */ 3534 3535static __always_inline void * 3536__cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller) 3537{ 3538 unsigned long save_flags; 3539 void *objp; 3540 3541 flags &= gfp_allowed_mask; 3542 3543 lockdep_trace_alloc(flags); 3544 3545 if (slab_should_failslab(cachep, flags)) 3546 return NULL; 3547 3548 cache_alloc_debugcheck_before(cachep, flags); 3549 local_irq_save(save_flags); 3550 objp = __do_cache_alloc(cachep, flags); 3551 local_irq_restore(save_flags); 3552 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); 3553 kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags, 3554 flags); 3555 prefetchw(objp); 3556 3557 if (likely(objp)) 3558 kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep)); 3559 3560 if (unlikely((flags & __GFP_ZERO) && objp)) 3561 memset(objp, 0, obj_size(cachep)); 3562 3563 return objp; 3564} 3565 3566/* 3567 * Caller needs to acquire correct kmem_list's list_lock 3568 */ 3569static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects, 3570 int node) 3571{ 3572 int i; 3573 struct kmem_list3 *l3; 3574 3575 for (i = 0; i < nr_objects; i++) { 3576 void *objp = objpp[i]; 3577 struct slab *slabp; 3578 3579 slabp = virt_to_slab(objp); 3580 l3 = cachep->nodelists[node]; 3581 list_del(&slabp->list); 3582 check_spinlock_acquired_node(cachep, node); 3583 check_slabp(cachep, slabp); 3584 slab_put_obj(cachep, slabp, objp, node); 3585 STATS_DEC_ACTIVE(cachep); 3586 l3->free_objects++; 3587 check_slabp(cachep, slabp); 3588 3589 /* fixup slab chains */ 3590 if (slabp->inuse == 0) { 3591 if (l3->free_objects > l3->free_limit) { 3592 l3->free_objects -= cachep->num; 3593 /* No need to drop any previously held 3594 * lock here, even if we have a off-slab slab 3595 * descriptor it is guaranteed to come from 3596 * a different cache, refer to comments before 3597 * alloc_slabmgmt. 3598 */ 3599 slab_destroy(cachep, slabp); 3600 } else { 3601 list_add(&slabp->list, &l3->slabs_free); 3602 } 3603 } else { 3604 /* Unconditionally move a slab to the end of the 3605 * partial list on free - maximum time for the 3606 * other objects to be freed, too. 3607 */ 3608 list_add_tail(&slabp->list, &l3->slabs_partial); 3609 } 3610 } 3611} 3612 3613static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) 3614{ 3615 int batchcount; 3616 struct kmem_list3 *l3; 3617 int node = numa_mem_id(); 3618 3619 batchcount = ac->batchcount; 3620#if DEBUG 3621 BUG_ON(!batchcount || batchcount > ac->avail); 3622#endif 3623 check_irq_off(); 3624 l3 = cachep->nodelists[node]; 3625 spin_lock(&l3->list_lock); 3626 if (l3->shared) { 3627 struct array_cache *shared_array = l3->shared; 3628 int max = shared_array->limit - shared_array->avail; 3629 if (max) { 3630 if (batchcount > max) 3631 batchcount = max; 3632 memcpy(&(shared_array->entry[shared_array->avail]), 3633 ac->entry, sizeof(void *) * batchcount); 3634 shared_array->avail += batchcount; 3635 goto free_done; 3636 } 3637 } 3638 3639 free_block(cachep, ac->entry, batchcount, node); 3640free_done: 3641#if STATS 3642 { 3643 int i = 0; 3644 struct list_head *p; 3645 3646 p = l3->slabs_free.next; 3647 while (p != &(l3->slabs_free)) { 3648 struct slab *slabp; 3649 3650 slabp = list_entry(p, struct slab, list); 3651 BUG_ON(slabp->inuse); 3652 3653 i++; 3654 p = p->next; 3655 } 3656 STATS_SET_FREEABLE(cachep, i); 3657 } 3658#endif 3659 spin_unlock(&l3->list_lock); 3660 ac->avail -= batchcount; 3661 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); 3662} 3663 3664/* 3665 * Release an obj back to its cache. If the obj has a constructed state, it must 3666 * be in this state _before_ it is released. Called with disabled ints. 3667 */ 3668static inline void __cache_free(struct kmem_cache *cachep, void *objp, 3669 void *caller) 3670{ 3671 struct array_cache *ac = cpu_cache_get(cachep); 3672 3673 check_irq_off(); 3674 kmemleak_free_recursive(objp, cachep->flags); 3675 objp = cache_free_debugcheck(cachep, objp, caller); 3676 3677 kmemcheck_slab_free(cachep, objp, obj_size(cachep)); 3678 3679 /* 3680 * Skip calling cache_free_alien() when the platform is not numa. 3681 * This will avoid cache misses that happen while accessing slabp (which 3682 * is per page memory reference) to get nodeid. Instead use a global 3683 * variable to skip the call, which is mostly likely to be present in 3684 * the cache. 3685 */ 3686 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) 3687 return; 3688 3689 if (likely(ac->avail < ac->limit)) { 3690 STATS_INC_FREEHIT(cachep); 3691 ac->entry[ac->avail++] = objp; 3692 return; 3693 } else { 3694 STATS_INC_FREEMISS(cachep); 3695 cache_flusharray(cachep, ac); 3696 ac->entry[ac->avail++] = objp; 3697 } 3698} 3699 3700/** 3701 * kmem_cache_alloc - Allocate an object 3702 * @cachep: The cache to allocate from. 3703 * @flags: See kmalloc(). 3704 * 3705 * Allocate an object from this cache. The flags are only relevant 3706 * if the cache has no available objects. 3707 */ 3708void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3709{ 3710 void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0)); 3711 3712 trace_kmem_cache_alloc(_RET_IP_, ret, 3713 obj_size(cachep), cachep->buffer_size, flags); 3714 3715 return ret; 3716} 3717EXPORT_SYMBOL(kmem_cache_alloc); 3718 3719#ifdef CONFIG_TRACING 3720void * 3721kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags) 3722{ 3723 void *ret; 3724 3725 ret = __cache_alloc(cachep, flags, __builtin_return_address(0)); 3726 3727 trace_kmalloc(_RET_IP_, ret, 3728 size, slab_buffer_size(cachep), flags); 3729 return ret; 3730} 3731EXPORT_SYMBOL(kmem_cache_alloc_trace); 3732#endif 3733 3734#ifdef CONFIG_NUMA 3735void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) 3736{ 3737 void *ret = __cache_alloc_node(cachep, flags, nodeid, 3738 __builtin_return_address(0)); 3739 3740 trace_kmem_cache_alloc_node(_RET_IP_, ret, 3741 obj_size(cachep), cachep->buffer_size, 3742 flags, nodeid); 3743 3744 return ret; 3745} 3746EXPORT_SYMBOL(kmem_cache_alloc_node); 3747 3748#ifdef CONFIG_TRACING 3749void *kmem_cache_alloc_node_trace(size_t size, 3750 struct kmem_cache *cachep, 3751 gfp_t flags, 3752 int nodeid) 3753{ 3754 void *ret; 3755 3756 ret = __cache_alloc_node(cachep, flags, nodeid, 3757 __builtin_return_address(0)); 3758 trace_kmalloc_node(_RET_IP_, ret, 3759 size, slab_buffer_size(cachep), 3760 flags, nodeid); 3761 return ret; 3762} 3763EXPORT_SYMBOL(kmem_cache_alloc_node_trace); 3764#endif 3765 3766static __always_inline void * 3767__do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller) 3768{ 3769 struct kmem_cache *cachep; 3770 3771 cachep = kmem_find_general_cachep(size, flags); 3772 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3773 return cachep; 3774 return kmem_cache_alloc_node_trace(size, cachep, flags, node); 3775} 3776 3777#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING) 3778void *__kmalloc_node(size_t size, gfp_t flags, int node) 3779{ 3780 return __do_kmalloc_node(size, flags, node, 3781 __builtin_return_address(0)); 3782} 3783EXPORT_SYMBOL(__kmalloc_node); 3784 3785void *__kmalloc_node_track_caller(size_t size, gfp_t flags, 3786 int node, unsigned long caller) 3787{ 3788 return __do_kmalloc_node(size, flags, node, (void *)caller); 3789} 3790EXPORT_SYMBOL(__kmalloc_node_track_caller); 3791#else 3792void *__kmalloc_node(size_t size, gfp_t flags, int node) 3793{ 3794 return __do_kmalloc_node(size, flags, node, NULL); 3795} 3796EXPORT_SYMBOL(__kmalloc_node); 3797#endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */ 3798#endif /* CONFIG_NUMA */ 3799 3800/** 3801 * __do_kmalloc - allocate memory 3802 * @size: how many bytes of memory are required. 3803 * @flags: the type of memory to allocate (see kmalloc). 3804 * @caller: function caller for debug tracking of the caller 3805 */ 3806static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, 3807 void *caller) 3808{ 3809 struct kmem_cache *cachep; 3810 void *ret; 3811 3812 /* If you want to save a few bytes .text space: replace 3813 * __ with kmem_. 3814 * Then kmalloc uses the uninlined functions instead of the inline 3815 * functions. 3816 */ 3817 cachep = __find_general_cachep(size, flags); 3818 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3819 return cachep; 3820 ret = __cache_alloc(cachep, flags, caller); 3821 3822 trace_kmalloc((unsigned long) caller, ret, 3823 size, cachep->buffer_size, flags); 3824 3825 return ret; 3826} 3827 3828 3829#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING) 3830void *__kmalloc(size_t size, gfp_t flags) 3831{ 3832 return __do_kmalloc(size, flags, __builtin_return_address(0)); 3833} 3834EXPORT_SYMBOL(__kmalloc); 3835 3836void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller) 3837{ 3838 return __do_kmalloc(size, flags, (void *)caller); 3839} 3840EXPORT_SYMBOL(__kmalloc_track_caller); 3841 3842#else 3843void *__kmalloc(size_t size, gfp_t flags) 3844{ 3845 return __do_kmalloc(size, flags, NULL); 3846} 3847EXPORT_SYMBOL(__kmalloc); 3848#endif 3849 3850/** 3851 * kmem_cache_free - Deallocate an object 3852 * @cachep: The cache the allocation was from. 3853 * @objp: The previously allocated object. 3854 * 3855 * Free an object which was previously allocated from this 3856 * cache. 3857 */ 3858void kmem_cache_free(struct kmem_cache *cachep, void *objp) 3859{ 3860 unsigned long flags; 3861 3862 local_irq_save(flags); 3863 debug_check_no_locks_freed(objp, obj_size(cachep)); 3864 if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) 3865 debug_check_no_obj_freed(objp, obj_size(cachep)); 3866 __cache_free(cachep, objp, __builtin_return_address(0)); 3867 local_irq_restore(flags); 3868 3869 trace_kmem_cache_free(_RET_IP_, objp); 3870} 3871EXPORT_SYMBOL(kmem_cache_free); 3872 3873/** 3874 * kfree - free previously allocated memory 3875 * @objp: pointer returned by kmalloc. 3876 * 3877 * If @objp is NULL, no operation is performed. 3878 * 3879 * Don't free memory not originally allocated by kmalloc() 3880 * or you will run into trouble. 3881 */ 3882void kfree(const void *objp) 3883{ 3884 struct kmem_cache *c; 3885 unsigned long flags; 3886 3887 trace_kfree(_RET_IP_, objp); 3888 3889 if (unlikely(ZERO_OR_NULL_PTR(objp))) 3890 return; 3891 local_irq_save(flags); 3892 kfree_debugcheck(objp); 3893 c = virt_to_cache(objp); 3894 debug_check_no_locks_freed(objp, obj_size(c)); 3895 debug_check_no_obj_freed(objp, obj_size(c)); 3896 __cache_free(c, (void *)objp, __builtin_return_address(0)); 3897 local_irq_restore(flags); 3898} 3899EXPORT_SYMBOL(kfree); 3900 3901unsigned int kmem_cache_size(struct kmem_cache *cachep) 3902{ 3903 return obj_size(cachep); 3904} 3905EXPORT_SYMBOL(kmem_cache_size); 3906 3907/* 3908 * This initializes kmem_list3 or resizes various caches for all nodes. 3909 */ 3910static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp) 3911{ 3912 int node; 3913 struct kmem_list3 *l3; 3914 struct array_cache *new_shared; 3915 struct array_cache **new_alien = NULL; 3916 3917 for_each_online_node(node) { 3918 3919 if (use_alien_caches) { 3920 new_alien = alloc_alien_cache(node, cachep->limit, gfp); 3921 if (!new_alien) 3922 goto fail; 3923 } 3924 3925 new_shared = NULL; 3926 if (cachep->shared) { 3927 new_shared = alloc_arraycache(node, 3928 cachep->shared*cachep->batchcount, 3929 0xbaadf00d, gfp); 3930 if (!new_shared) { 3931 free_alien_cache(new_alien); 3932 goto fail; 3933 } 3934 } 3935 3936 l3 = cachep->nodelists[node]; 3937 if (l3) { 3938 struct array_cache *shared = l3->shared; 3939 3940 spin_lock_irq(&l3->list_lock); 3941 3942 if (shared) 3943 free_block(cachep, shared->entry, 3944 shared->avail, node); 3945 3946 l3->shared = new_shared; 3947 if (!l3->alien) { 3948 l3->alien = new_alien; 3949 new_alien = NULL; 3950 } 3951 l3->free_limit = (1 + nr_cpus_node(node)) * 3952 cachep->batchcount + cachep->num; 3953 spin_unlock_irq(&l3->list_lock); 3954 kfree(shared); 3955 free_alien_cache(new_alien); 3956 continue; 3957 } 3958 l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node); 3959 if (!l3) { 3960 free_alien_cache(new_alien); 3961 kfree(new_shared); 3962 goto fail; 3963 } 3964 3965 kmem_list3_init(l3); 3966 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 + 3967 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 3968 l3->shared = new_shared; 3969 l3->alien = new_alien; 3970 l3->free_limit = (1 + nr_cpus_node(node)) * 3971 cachep->batchcount + cachep->num; 3972 cachep->nodelists[node] = l3; 3973 } 3974 return 0; 3975 3976fail: 3977 if (!cachep->next.next) { 3978 /* Cache is not active yet. Roll back what we did */ 3979 node--; 3980 while (node >= 0) { 3981 if (cachep->nodelists[node]) { 3982 l3 = cachep->nodelists[node]; 3983 3984 kfree(l3->shared); 3985 free_alien_cache(l3->alien); 3986 kfree(l3); 3987 cachep->nodelists[node] = NULL; 3988 } 3989 node--; 3990 } 3991 } 3992 return -ENOMEM; 3993} 3994 3995struct ccupdate_struct { 3996 struct kmem_cache *cachep; 3997 struct array_cache *new[0]; 3998}; 3999 4000static void do_ccupdate_local(void *info) 4001{ 4002 struct ccupdate_struct *new = info; 4003 struct array_cache *old; 4004 4005 check_irq_off(); 4006 old = cpu_cache_get(new->cachep); 4007 4008 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()]; 4009 new->new[smp_processor_id()] = old; 4010} 4011 4012/* Always called with the cache_chain_mutex held */ 4013static int do_tune_cpucache(struct kmem_cache *cachep, int limit, 4014 int batchcount, int shared, gfp_t gfp) 4015{ 4016 struct ccupdate_struct *new; 4017 int i; 4018 4019 new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *), 4020 gfp); 4021 if (!new) 4022 return -ENOMEM; 4023 4024 for_each_online_cpu(i) { 4025 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit, 4026 batchcount, gfp); 4027 if (!new->new[i]) { 4028 for (i--; i >= 0; i--) 4029 kfree(new->new[i]); 4030 kfree(new); 4031 return -ENOMEM; 4032 } 4033 } 4034 new->cachep = cachep; 4035 4036 on_each_cpu(do_ccupdate_local, (void *)new, 1); 4037 4038 check_irq_on(); 4039 cachep->batchcount = batchcount; 4040 cachep->limit = limit; 4041 cachep->shared = shared; 4042 4043 for_each_online_cpu(i) { 4044 struct array_cache *ccold = new->new[i]; 4045 if (!ccold) 4046 continue; 4047 spin_lock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock); 4048 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i)); 4049 spin_unlock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock); 4050 kfree(ccold); 4051 } 4052 kfree(new); 4053 return alloc_kmemlist(cachep, gfp); 4054} 4055 4056/* Called with cache_chain_mutex held always */ 4057static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) 4058{ 4059 int err; 4060 int limit, shared; 4061 4062 /* 4063 * The head array serves three purposes: 4064 * - create a LIFO ordering, i.e. return objects that are cache-warm 4065 * - reduce the number of spinlock operations. 4066 * - reduce the number of linked list operations on the slab and 4067 * bufctl chains: array operations are cheaper. 4068 * The numbers are guessed, we should auto-tune as described by 4069 * Bonwick. 4070 */ 4071 if (cachep->buffer_size > 131072) 4072 limit = 1; 4073 else if (cachep->buffer_size > PAGE_SIZE) 4074 limit = 8; 4075 else if (cachep->buffer_size > 1024) 4076 limit = 24; 4077 else if (cachep->buffer_size > 256) 4078 limit = 54; 4079 else 4080 limit = 120; 4081 4082 /* 4083 * CPU bound tasks (e.g. network routing) can exhibit cpu bound 4084 * allocation behaviour: Most allocs on one cpu, most free operations 4085 * on another cpu. For these cases, an efficient object passing between 4086 * cpus is necessary. This is provided by a shared array. The array 4087 * replaces Bonwick's magazine layer. 4088 * On uniprocessor, it's functionally equivalent (but less efficient) 4089 * to a larger limit. Thus disabled by default. 4090 */ 4091 shared = 0; 4092 if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1) 4093 shared = 8; 4094 4095#if DEBUG 4096 /* 4097 * With debugging enabled, large batchcount lead to excessively long 4098 * periods with disabled local interrupts. Limit the batchcount 4099 */ 4100 if (limit > 32) 4101 limit = 32; 4102#endif 4103 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared, gfp); 4104 if (err) 4105 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n", 4106 cachep->name, -err); 4107 return err; 4108} 4109 4110/* 4111 * Drain an array if it contains any elements taking the l3 lock only if 4112 * necessary. Note that the l3 listlock also protects the array_cache 4113 * if drain_array() is used on the shared array. 4114 */ 4115static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3, 4116 struct array_cache *ac, int force, int node) 4117{ 4118 int tofree; 4119 4120 if (!ac || !ac->avail) 4121 return; 4122 if (ac->touched && !force) { 4123 ac->touched = 0; 4124 } else { 4125 spin_lock_irq(&l3->list_lock); 4126 if (ac->avail) { 4127 tofree = force ? ac->avail : (ac->limit + 4) / 5; 4128 if (tofree > ac->avail) 4129 tofree = (ac->avail + 1) / 2; 4130 free_block(cachep, ac->entry, tofree, node); 4131 ac->avail -= tofree; 4132 memmove(ac->entry, &(ac->entry[tofree]), 4133 sizeof(void *) * ac->avail); 4134 } 4135 spin_unlock_irq(&l3->list_lock); 4136 } 4137} 4138 4139/** 4140 * cache_reap - Reclaim memory from caches. 4141 * @w: work descriptor 4142 * 4143 * Called from workqueue/eventd every few seconds. 4144 * Purpose: 4145 * - clear the per-cpu caches for this CPU. 4146 * - return freeable pages to the main free memory pool. 4147 * 4148 * If we cannot acquire the cache chain mutex then just give up - we'll try 4149 * again on the next iteration. 4150 */ 4151static void cache_reap(struct work_struct *w) 4152{ 4153 struct kmem_cache *searchp; 4154 struct kmem_list3 *l3; 4155 int node = numa_mem_id(); 4156 struct delayed_work *work = to_delayed_work(w); 4157 4158 if (!mutex_trylock(&cache_chain_mutex)) 4159 /* Give up. Setup the next iteration. */ 4160 goto out; 4161 4162 list_for_each_entry(searchp, &cache_chain, next) { 4163 check_irq_on(); 4164 4165 /* 4166 * We only take the l3 lock if absolutely necessary and we 4167 * have established with reasonable certainty that 4168 * we can do some work if the lock was obtained. 4169 */ 4170 l3 = searchp->nodelists[node]; 4171 4172 reap_alien(searchp, l3); 4173 4174 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node); 4175 4176 /* 4177 * These are racy checks but it does not matter 4178 * if we skip one check or scan twice. 4179 */ 4180 if (time_after(l3->next_reap, jiffies)) 4181 goto next; 4182 4183 l3->next_reap = jiffies + REAPTIMEOUT_LIST3; 4184 4185 drain_array(searchp, l3, l3->shared, 0, node); 4186 4187 if (l3->free_touched) 4188 l3->free_touched = 0; 4189 else { 4190 int freed; 4191 4192 freed = drain_freelist(searchp, l3, (l3->free_limit + 4193 5 * searchp->num - 1) / (5 * searchp->num)); 4194 STATS_ADD_REAPED(searchp, freed); 4195 } 4196next: 4197 cond_resched(); 4198 } 4199 check_irq_on(); 4200 mutex_unlock(&cache_chain_mutex); 4201 next_reap_node(); 4202out: 4203 /* Set up the next iteration */ 4204 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC)); 4205} 4206 4207#ifdef CONFIG_SLABINFO 4208 4209static void print_slabinfo_header(struct seq_file *m) 4210{ 4211 /* 4212 * Output format version, so at least we can change it 4213 * without _too_ many complaints. 4214 */ 4215#if STATS 4216 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 4217#else 4218 seq_puts(m, "slabinfo - version: 2.1\n"); 4219#endif 4220 seq_puts(m, "# name <active_objs> <num_objs> <objsize> " 4221 "<objperslab> <pagesperslab>"); 4222 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 4223 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 4224#if STATS 4225 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> " 4226 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 4227 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 4228#endif 4229 seq_putc(m, '\n'); 4230} 4231 4232static void *s_start(struct seq_file *m, loff_t *pos) 4233{ 4234 loff_t n = *pos; 4235 4236 mutex_lock(&cache_chain_mutex); 4237 if (!n) 4238 print_slabinfo_header(m); 4239 4240 return seq_list_start(&cache_chain, *pos); 4241} 4242 4243static void *s_next(struct seq_file *m, void *p, loff_t *pos) 4244{ 4245 return seq_list_next(p, &cache_chain, pos); 4246} 4247 4248static void s_stop(struct seq_file *m, void *p) 4249{ 4250 mutex_unlock(&cache_chain_mutex); 4251} 4252 4253static int s_show(struct seq_file *m, void *p) 4254{ 4255 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next); 4256 struct slab *slabp; 4257 unsigned long active_objs; 4258 unsigned long num_objs; 4259 unsigned long active_slabs = 0; 4260 unsigned long num_slabs, free_objects = 0, shared_avail = 0; 4261 const char *name; 4262 char *error = NULL; 4263 int node; 4264 struct kmem_list3 *l3; 4265 4266 active_objs = 0; 4267 num_slabs = 0; 4268 for_each_online_node(node) { 4269 l3 = cachep->nodelists[node]; 4270 if (!l3) 4271 continue; 4272 4273 check_irq_on(); 4274 spin_lock_irq(&l3->list_lock); 4275 4276 list_for_each_entry(slabp, &l3->slabs_full, list) { 4277 if (slabp->inuse != cachep->num && !error) 4278 error = "slabs_full accounting error"; 4279 active_objs += cachep->num; 4280 active_slabs++; 4281 } 4282 list_for_each_entry(slabp, &l3->slabs_partial, list) { 4283 if (slabp->inuse == cachep->num && !error) 4284 error = "slabs_partial inuse accounting error"; 4285 if (!slabp->inuse && !error) 4286 error = "slabs_partial/inuse accounting error"; 4287 active_objs += slabp->inuse; 4288 active_slabs++; 4289 } 4290 list_for_each_entry(slabp, &l3->slabs_free, list) { 4291 if (slabp->inuse && !error) 4292 error = "slabs_free/inuse accounting error"; 4293 num_slabs++; 4294 } 4295 free_objects += l3->free_objects; 4296 if (l3->shared) 4297 shared_avail += l3->shared->avail; 4298 4299 spin_unlock_irq(&l3->list_lock); 4300 } 4301 num_slabs += active_slabs; 4302 num_objs = num_slabs * cachep->num; 4303 if (num_objs - active_objs != free_objects && !error) 4304 error = "free_objects accounting error"; 4305 4306 name = cachep->name; 4307 if (error) 4308 printk(KERN_ERR "slab: cache %s error: %s\n", name, error); 4309 4310 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 4311 name, active_objs, num_objs, cachep->buffer_size, 4312 cachep->num, (1 << cachep->gfporder)); 4313 seq_printf(m, " : tunables %4u %4u %4u", 4314 cachep->limit, cachep->batchcount, cachep->shared); 4315 seq_printf(m, " : slabdata %6lu %6lu %6lu", 4316 active_slabs, num_slabs, shared_avail); 4317#if STATS 4318 { /* list3 stats */ 4319 unsigned long high = cachep->high_mark; 4320 unsigned long allocs = cachep->num_allocations; 4321 unsigned long grown = cachep->grown; 4322 unsigned long reaped = cachep->reaped; 4323 unsigned long errors = cachep->errors; 4324 unsigned long max_freeable = cachep->max_freeable; 4325 unsigned long node_allocs = cachep->node_allocs; 4326 unsigned long node_frees = cachep->node_frees; 4327 unsigned long overflows = cachep->node_overflow; 4328 4329 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu " 4330 "%4lu %4lu %4lu %4lu %4lu", 4331 allocs, high, grown, 4332 reaped, errors, max_freeable, node_allocs, 4333 node_frees, overflows); 4334 } 4335 /* cpu stats */ 4336 { 4337 unsigned long allochit = atomic_read(&cachep->allochit); 4338 unsigned long allocmiss = atomic_read(&cachep->allocmiss); 4339 unsigned long freehit = atomic_read(&cachep->freehit); 4340 unsigned long freemiss = atomic_read(&cachep->freemiss); 4341 4342 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", 4343 allochit, allocmiss, freehit, freemiss); 4344 } 4345#endif 4346 seq_putc(m, '\n'); 4347 return 0; 4348} 4349 4350/* 4351 * slabinfo_op - iterator that generates /proc/slabinfo 4352 * 4353 * Output layout: 4354 * cache-name 4355 * num-active-objs 4356 * total-objs 4357 * object size 4358 * num-active-slabs 4359 * total-slabs 4360 * num-pages-per-slab 4361 * + further values on SMP and with statistics enabled 4362 */ 4363 4364static const struct seq_operations slabinfo_op = { 4365 .start = s_start, 4366 .next = s_next, 4367 .stop = s_stop, 4368 .show = s_show, 4369}; 4370 4371#define MAX_SLABINFO_WRITE 128 4372/** 4373 * slabinfo_write - Tuning for the slab allocator 4374 * @file: unused 4375 * @buffer: user buffer 4376 * @count: data length 4377 * @ppos: unused 4378 */ 4379static ssize_t slabinfo_write(struct file *file, const char __user *buffer, 4380 size_t count, loff_t *ppos) 4381{ 4382 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; 4383 int limit, batchcount, shared, res; 4384 struct kmem_cache *cachep; 4385 4386 if (count > MAX_SLABINFO_WRITE) 4387 return -EINVAL; 4388 if (copy_from_user(&kbuf, buffer, count)) 4389 return -EFAULT; 4390 kbuf[MAX_SLABINFO_WRITE] = '\0'; 4391 4392 tmp = strchr(kbuf, ' '); 4393 if (!tmp) 4394 return -EINVAL; 4395 *tmp = '\0'; 4396 tmp++; 4397 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) 4398 return -EINVAL; 4399 4400 /* Find the cache in the chain of caches. */ 4401 mutex_lock(&cache_chain_mutex); 4402 res = -EINVAL; 4403 list_for_each_entry(cachep, &cache_chain, next) { 4404 if (!strcmp(cachep->name, kbuf)) { 4405 if (limit < 1 || batchcount < 1 || 4406 batchcount > limit || shared < 0) { 4407 res = 0; 4408 } else { 4409 res = do_tune_cpucache(cachep, limit, 4410 batchcount, shared, 4411 GFP_KERNEL); 4412 } 4413 break; 4414 } 4415 } 4416 mutex_unlock(&cache_chain_mutex); 4417 if (res >= 0) 4418 res = count; 4419 return res; 4420} 4421 4422static int slabinfo_open(struct inode *inode, struct file *file) 4423{ 4424 return seq_open(file, &slabinfo_op); 4425} 4426 4427static const struct file_operations proc_slabinfo_operations = { 4428 .open = slabinfo_open, 4429 .read = seq_read, 4430 .write = slabinfo_write, 4431 .llseek = seq_lseek, 4432 .release = seq_release, 4433}; 4434 4435#ifdef CONFIG_DEBUG_SLAB_LEAK 4436 4437static void *leaks_start(struct seq_file *m, loff_t *pos) 4438{ 4439 mutex_lock(&cache_chain_mutex); 4440 return seq_list_start(&cache_chain, *pos); 4441} 4442 4443static inline int add_caller(unsigned long *n, unsigned long v) 4444{ 4445 unsigned long *p; 4446 int l; 4447 if (!v) 4448 return 1; 4449 l = n[1]; 4450 p = n + 2; 4451 while (l) { 4452 int i = l/2; 4453 unsigned long *q = p + 2 * i; 4454 if (*q == v) { 4455 q[1]++; 4456 return 1; 4457 } 4458 if (*q > v) { 4459 l = i; 4460 } else { 4461 p = q + 2; 4462 l -= i + 1; 4463 } 4464 } 4465 if (++n[1] == n[0]) 4466 return 0; 4467 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n)); 4468 p[0] = v; 4469 p[1] = 1; 4470 return 1; 4471} 4472 4473static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s) 4474{ 4475 void *p; 4476 int i; 4477 if (n[0] == n[1]) 4478 return; 4479 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) { 4480 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE) 4481 continue; 4482 if (!add_caller(n, (unsigned long)*dbg_userword(c, p))) 4483 return; 4484 } 4485} 4486 4487static void show_symbol(struct seq_file *m, unsigned long address) 4488{ 4489#ifdef CONFIG_KALLSYMS 4490 unsigned long offset, size; 4491 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN]; 4492 4493 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) { 4494 seq_printf(m, "%s+%#lx/%#lx", name, offset, size); 4495 if (modname[0]) 4496 seq_printf(m, " [%s]", modname); 4497 return; 4498 } 4499#endif 4500 seq_printf(m, "%p", (void *)address); 4501} 4502 4503static int leaks_show(struct seq_file *m, void *p) 4504{ 4505 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next); 4506 struct slab *slabp; 4507 struct kmem_list3 *l3; 4508 const char *name; 4509 unsigned long *n = m->private; 4510 int node; 4511 int i; 4512 4513 if (!(cachep->flags & SLAB_STORE_USER)) 4514 return 0; 4515 if (!(cachep->flags & SLAB_RED_ZONE)) 4516 return 0; 4517 4518 /* OK, we can do it */ 4519 4520 n[1] = 0; 4521 4522 for_each_online_node(node) { 4523 l3 = cachep->nodelists[node]; 4524 if (!l3) 4525 continue; 4526 4527 check_irq_on(); 4528 spin_lock_irq(&l3->list_lock); 4529 4530 list_for_each_entry(slabp, &l3->slabs_full, list) 4531 handle_slab(n, cachep, slabp); 4532 list_for_each_entry(slabp, &l3->slabs_partial, list) 4533 handle_slab(n, cachep, slabp); 4534 spin_unlock_irq(&l3->list_lock); 4535 } 4536 name = cachep->name; 4537 if (n[0] == n[1]) { 4538 /* Increase the buffer size */ 4539 mutex_unlock(&cache_chain_mutex); 4540 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL); 4541 if (!m->private) { 4542 /* Too bad, we are really out */ 4543 m->private = n; 4544 mutex_lock(&cache_chain_mutex); 4545 return -ENOMEM; 4546 } 4547 *(unsigned long *)m->private = n[0] * 2; 4548 kfree(n); 4549 mutex_lock(&cache_chain_mutex); 4550 /* Now make sure this entry will be retried */ 4551 m->count = m->size; 4552 return 0; 4553 } 4554 for (i = 0; i < n[1]; i++) { 4555 seq_printf(m, "%s: %lu ", name, n[2*i+3]); 4556 show_symbol(m, n[2*i+2]); 4557 seq_putc(m, '\n'); 4558 } 4559 4560 return 0; 4561} 4562 4563static const struct seq_operations slabstats_op = { 4564 .start = leaks_start, 4565 .next = s_next, 4566 .stop = s_stop, 4567 .show = leaks_show, 4568}; 4569 4570static int slabstats_open(struct inode *inode, struct file *file) 4571{ 4572 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL); 4573 int ret = -ENOMEM; 4574 if (n) { 4575 ret = seq_open(file, &slabstats_op); 4576 if (!ret) { 4577 struct seq_file *m = file->private_data; 4578 *n = PAGE_SIZE / (2 * sizeof(unsigned long)); 4579 m->private = n; 4580 n = NULL; 4581 } 4582 kfree(n); 4583 } 4584 return ret; 4585} 4586 4587static const struct file_operations proc_slabstats_operations = { 4588 .open = slabstats_open, 4589 .read = seq_read, 4590 .llseek = seq_lseek, 4591 .release = seq_release_private, 4592}; 4593#endif 4594 4595static int __init slab_proc_init(void) 4596{ 4597 proc_create("slabinfo",S_IWUSR|S_IRUSR,NULL,&proc_slabinfo_operations); 4598#ifdef CONFIG_DEBUG_SLAB_LEAK 4599 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations); 4600#endif 4601 return 0; 4602} 4603module_init(slab_proc_init); 4604#endif 4605 4606/** 4607 * ksize - get the actual amount of memory allocated for a given object 4608 * @objp: Pointer to the object 4609 * 4610 * kmalloc may internally round up allocations and return more memory 4611 * than requested. ksize() can be used to determine the actual amount of 4612 * memory allocated. The caller may use this additional memory, even though 4613 * a smaller amount of memory was initially specified with the kmalloc call. 4614 * The caller must guarantee that objp points to a valid object previously 4615 * allocated with either kmalloc() or kmem_cache_alloc(). The object 4616 * must not be freed during the duration of the call. 4617 */ 4618size_t ksize(const void *objp) 4619{ 4620 BUG_ON(!objp); 4621 if (unlikely(objp == ZERO_SIZE_PTR)) 4622 return 0; 4623 4624 return obj_size(virt_to_cache(objp)); 4625} 4626EXPORT_SYMBOL(ksize); 4627