slab.c revision 3df1cccdfb3fab6aa9176beb655d802eb384eabc
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 start=%p, len=%d\n", 1945 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). Hexdump:\n", 3055 cachep->name, cachep->num, slabp, slabp->inuse); 3056 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp, 3057 sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t), 3058 1); 3059 BUG(); 3060 } 3061} 3062#else 3063#define kfree_debugcheck(x) do { } while(0) 3064#define cache_free_debugcheck(x,objp,z) (objp) 3065#define check_slabp(x,y) do { } while(0) 3066#endif 3067 3068static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) 3069{ 3070 int batchcount; 3071 struct kmem_list3 *l3; 3072 struct array_cache *ac; 3073 int node; 3074 3075retry: 3076 check_irq_off(); 3077 node = numa_mem_id(); 3078 ac = cpu_cache_get(cachep); 3079 batchcount = ac->batchcount; 3080 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { 3081 /* 3082 * If there was little recent activity on this cache, then 3083 * perform only a partial refill. Otherwise we could generate 3084 * refill bouncing. 3085 */ 3086 batchcount = BATCHREFILL_LIMIT; 3087 } 3088 l3 = cachep->nodelists[node]; 3089 3090 BUG_ON(ac->avail > 0 || !l3); 3091 spin_lock(&l3->list_lock); 3092 3093 /* See if we can refill from the shared array */ 3094 if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) { 3095 l3->shared->touched = 1; 3096 goto alloc_done; 3097 } 3098 3099 while (batchcount > 0) { 3100 struct list_head *entry; 3101 struct slab *slabp; 3102 /* Get slab alloc is to come from. */ 3103 entry = l3->slabs_partial.next; 3104 if (entry == &l3->slabs_partial) { 3105 l3->free_touched = 1; 3106 entry = l3->slabs_free.next; 3107 if (entry == &l3->slabs_free) 3108 goto must_grow; 3109 } 3110 3111 slabp = list_entry(entry, struct slab, list); 3112 check_slabp(cachep, slabp); 3113 check_spinlock_acquired(cachep); 3114 3115 /* 3116 * The slab was either on partial or free list so 3117 * there must be at least one object available for 3118 * allocation. 3119 */ 3120 BUG_ON(slabp->inuse >= cachep->num); 3121 3122 while (slabp->inuse < cachep->num && batchcount--) { 3123 STATS_INC_ALLOCED(cachep); 3124 STATS_INC_ACTIVE(cachep); 3125 STATS_SET_HIGH(cachep); 3126 3127 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp, 3128 node); 3129 } 3130 check_slabp(cachep, slabp); 3131 3132 /* move slabp to correct slabp list: */ 3133 list_del(&slabp->list); 3134 if (slabp->free == BUFCTL_END) 3135 list_add(&slabp->list, &l3->slabs_full); 3136 else 3137 list_add(&slabp->list, &l3->slabs_partial); 3138 } 3139 3140must_grow: 3141 l3->free_objects -= ac->avail; 3142alloc_done: 3143 spin_unlock(&l3->list_lock); 3144 3145 if (unlikely(!ac->avail)) { 3146 int x; 3147 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL); 3148 3149 /* cache_grow can reenable interrupts, then ac could change. */ 3150 ac = cpu_cache_get(cachep); 3151 if (!x && ac->avail == 0) /* no objects in sight? abort */ 3152 return NULL; 3153 3154 if (!ac->avail) /* objects refilled by interrupt? */ 3155 goto retry; 3156 } 3157 ac->touched = 1; 3158 return ac->entry[--ac->avail]; 3159} 3160 3161static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, 3162 gfp_t flags) 3163{ 3164 might_sleep_if(flags & __GFP_WAIT); 3165#if DEBUG 3166 kmem_flagcheck(cachep, flags); 3167#endif 3168} 3169 3170#if DEBUG 3171static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, 3172 gfp_t flags, void *objp, void *caller) 3173{ 3174 if (!objp) 3175 return objp; 3176 if (cachep->flags & SLAB_POISON) { 3177#ifdef CONFIG_DEBUG_PAGEALLOC 3178 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) 3179 kernel_map_pages(virt_to_page(objp), 3180 cachep->buffer_size / PAGE_SIZE, 1); 3181 else 3182 check_poison_obj(cachep, objp); 3183#else 3184 check_poison_obj(cachep, objp); 3185#endif 3186 poison_obj(cachep, objp, POISON_INUSE); 3187 } 3188 if (cachep->flags & SLAB_STORE_USER) 3189 *dbg_userword(cachep, objp) = caller; 3190 3191 if (cachep->flags & SLAB_RED_ZONE) { 3192 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || 3193 *dbg_redzone2(cachep, objp) != RED_INACTIVE) { 3194 slab_error(cachep, "double free, or memory outside" 3195 " object was overwritten"); 3196 printk(KERN_ERR 3197 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n", 3198 objp, *dbg_redzone1(cachep, objp), 3199 *dbg_redzone2(cachep, objp)); 3200 } 3201 *dbg_redzone1(cachep, objp) = RED_ACTIVE; 3202 *dbg_redzone2(cachep, objp) = RED_ACTIVE; 3203 } 3204#ifdef CONFIG_DEBUG_SLAB_LEAK 3205 { 3206 struct slab *slabp; 3207 unsigned objnr; 3208 3209 slabp = page_get_slab(virt_to_head_page(objp)); 3210 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size; 3211 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE; 3212 } 3213#endif 3214 objp += obj_offset(cachep); 3215 if (cachep->ctor && cachep->flags & SLAB_POISON) 3216 cachep->ctor(objp); 3217 if (ARCH_SLAB_MINALIGN && 3218 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) { 3219 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n", 3220 objp, (int)ARCH_SLAB_MINALIGN); 3221 } 3222 return objp; 3223} 3224#else 3225#define cache_alloc_debugcheck_after(a,b,objp,d) (objp) 3226#endif 3227 3228static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags) 3229{ 3230 if (cachep == &cache_cache) 3231 return false; 3232 3233 return should_failslab(obj_size(cachep), flags, cachep->flags); 3234} 3235 3236static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3237{ 3238 void *objp; 3239 struct array_cache *ac; 3240 3241 check_irq_off(); 3242 3243 ac = cpu_cache_get(cachep); 3244 if (likely(ac->avail)) { 3245 STATS_INC_ALLOCHIT(cachep); 3246 ac->touched = 1; 3247 objp = ac->entry[--ac->avail]; 3248 } else { 3249 STATS_INC_ALLOCMISS(cachep); 3250 objp = cache_alloc_refill(cachep, flags); 3251 /* 3252 * the 'ac' may be updated by cache_alloc_refill(), 3253 * and kmemleak_erase() requires its correct value. 3254 */ 3255 ac = cpu_cache_get(cachep); 3256 } 3257 /* 3258 * To avoid a false negative, if an object that is in one of the 3259 * per-CPU caches is leaked, we need to make sure kmemleak doesn't 3260 * treat the array pointers as a reference to the object. 3261 */ 3262 if (objp) 3263 kmemleak_erase(&ac->entry[ac->avail]); 3264 return objp; 3265} 3266 3267#ifdef CONFIG_NUMA 3268/* 3269 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY. 3270 * 3271 * If we are in_interrupt, then process context, including cpusets and 3272 * mempolicy, may not apply and should not be used for allocation policy. 3273 */ 3274static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) 3275{ 3276 int nid_alloc, nid_here; 3277 3278 if (in_interrupt() || (flags & __GFP_THISNODE)) 3279 return NULL; 3280 nid_alloc = nid_here = numa_mem_id(); 3281 get_mems_allowed(); 3282 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) 3283 nid_alloc = cpuset_slab_spread_node(); 3284 else if (current->mempolicy) 3285 nid_alloc = slab_node(current->mempolicy); 3286 put_mems_allowed(); 3287 if (nid_alloc != nid_here) 3288 return ____cache_alloc_node(cachep, flags, nid_alloc); 3289 return NULL; 3290} 3291 3292/* 3293 * Fallback function if there was no memory available and no objects on a 3294 * certain node and fall back is permitted. First we scan all the 3295 * available nodelists for available objects. If that fails then we 3296 * perform an allocation without specifying a node. This allows the page 3297 * allocator to do its reclaim / fallback magic. We then insert the 3298 * slab into the proper nodelist and then allocate from it. 3299 */ 3300static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) 3301{ 3302 struct zonelist *zonelist; 3303 gfp_t local_flags; 3304 struct zoneref *z; 3305 struct zone *zone; 3306 enum zone_type high_zoneidx = gfp_zone(flags); 3307 void *obj = NULL; 3308 int nid; 3309 3310 if (flags & __GFP_THISNODE) 3311 return NULL; 3312 3313 get_mems_allowed(); 3314 zonelist = node_zonelist(slab_node(current->mempolicy), flags); 3315 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); 3316 3317retry: 3318 /* 3319 * Look through allowed nodes for objects available 3320 * from existing per node queues. 3321 */ 3322 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { 3323 nid = zone_to_nid(zone); 3324 3325 if (cpuset_zone_allowed_hardwall(zone, flags) && 3326 cache->nodelists[nid] && 3327 cache->nodelists[nid]->free_objects) { 3328 obj = ____cache_alloc_node(cache, 3329 flags | GFP_THISNODE, nid); 3330 if (obj) 3331 break; 3332 } 3333 } 3334 3335 if (!obj) { 3336 /* 3337 * This allocation will be performed within the constraints 3338 * of the current cpuset / memory policy requirements. 3339 * We may trigger various forms of reclaim on the allowed 3340 * set and go into memory reserves if necessary. 3341 */ 3342 if (local_flags & __GFP_WAIT) 3343 local_irq_enable(); 3344 kmem_flagcheck(cache, flags); 3345 obj = kmem_getpages(cache, local_flags, numa_mem_id()); 3346 if (local_flags & __GFP_WAIT) 3347 local_irq_disable(); 3348 if (obj) { 3349 /* 3350 * Insert into the appropriate per node queues 3351 */ 3352 nid = page_to_nid(virt_to_page(obj)); 3353 if (cache_grow(cache, flags, nid, obj)) { 3354 obj = ____cache_alloc_node(cache, 3355 flags | GFP_THISNODE, nid); 3356 if (!obj) 3357 /* 3358 * Another processor may allocate the 3359 * objects in the slab since we are 3360 * not holding any locks. 3361 */ 3362 goto retry; 3363 } else { 3364 /* cache_grow already freed obj */ 3365 obj = NULL; 3366 } 3367 } 3368 } 3369 put_mems_allowed(); 3370 return obj; 3371} 3372 3373/* 3374 * A interface to enable slab creation on nodeid 3375 */ 3376static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, 3377 int nodeid) 3378{ 3379 struct list_head *entry; 3380 struct slab *slabp; 3381 struct kmem_list3 *l3; 3382 void *obj; 3383 int x; 3384 3385 l3 = cachep->nodelists[nodeid]; 3386 BUG_ON(!l3); 3387 3388retry: 3389 check_irq_off(); 3390 spin_lock(&l3->list_lock); 3391 entry = l3->slabs_partial.next; 3392 if (entry == &l3->slabs_partial) { 3393 l3->free_touched = 1; 3394 entry = l3->slabs_free.next; 3395 if (entry == &l3->slabs_free) 3396 goto must_grow; 3397 } 3398 3399 slabp = list_entry(entry, struct slab, list); 3400 check_spinlock_acquired_node(cachep, nodeid); 3401 check_slabp(cachep, slabp); 3402 3403 STATS_INC_NODEALLOCS(cachep); 3404 STATS_INC_ACTIVE(cachep); 3405 STATS_SET_HIGH(cachep); 3406 3407 BUG_ON(slabp->inuse == cachep->num); 3408 3409 obj = slab_get_obj(cachep, slabp, nodeid); 3410 check_slabp(cachep, slabp); 3411 l3->free_objects--; 3412 /* move slabp to correct slabp list: */ 3413 list_del(&slabp->list); 3414 3415 if (slabp->free == BUFCTL_END) 3416 list_add(&slabp->list, &l3->slabs_full); 3417 else 3418 list_add(&slabp->list, &l3->slabs_partial); 3419 3420 spin_unlock(&l3->list_lock); 3421 goto done; 3422 3423must_grow: 3424 spin_unlock(&l3->list_lock); 3425 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL); 3426 if (x) 3427 goto retry; 3428 3429 return fallback_alloc(cachep, flags); 3430 3431done: 3432 return obj; 3433} 3434 3435/** 3436 * kmem_cache_alloc_node - Allocate an object on the specified node 3437 * @cachep: The cache to allocate from. 3438 * @flags: See kmalloc(). 3439 * @nodeid: node number of the target node. 3440 * @caller: return address of caller, used for debug information 3441 * 3442 * Identical to kmem_cache_alloc but it will allocate memory on the given 3443 * node, which can improve the performance for cpu bound structures. 3444 * 3445 * Fallback to other node is possible if __GFP_THISNODE is not set. 3446 */ 3447static __always_inline void * 3448__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, 3449 void *caller) 3450{ 3451 unsigned long save_flags; 3452 void *ptr; 3453 int slab_node = numa_mem_id(); 3454 3455 flags &= gfp_allowed_mask; 3456 3457 lockdep_trace_alloc(flags); 3458 3459 if (slab_should_failslab(cachep, flags)) 3460 return NULL; 3461 3462 cache_alloc_debugcheck_before(cachep, flags); 3463 local_irq_save(save_flags); 3464 3465 if (nodeid == NUMA_NO_NODE) 3466 nodeid = slab_node; 3467 3468 if (unlikely(!cachep->nodelists[nodeid])) { 3469 /* Node not bootstrapped yet */ 3470 ptr = fallback_alloc(cachep, flags); 3471 goto out; 3472 } 3473 3474 if (nodeid == slab_node) { 3475 /* 3476 * Use the locally cached objects if possible. 3477 * However ____cache_alloc does not allow fallback 3478 * to other nodes. It may fail while we still have 3479 * objects on other nodes available. 3480 */ 3481 ptr = ____cache_alloc(cachep, flags); 3482 if (ptr) 3483 goto out; 3484 } 3485 /* ___cache_alloc_node can fall back to other nodes */ 3486 ptr = ____cache_alloc_node(cachep, flags, nodeid); 3487 out: 3488 local_irq_restore(save_flags); 3489 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller); 3490 kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags, 3491 flags); 3492 3493 if (likely(ptr)) 3494 kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep)); 3495 3496 if (unlikely((flags & __GFP_ZERO) && ptr)) 3497 memset(ptr, 0, obj_size(cachep)); 3498 3499 return ptr; 3500} 3501 3502static __always_inline void * 3503__do_cache_alloc(struct kmem_cache *cache, gfp_t flags) 3504{ 3505 void *objp; 3506 3507 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) { 3508 objp = alternate_node_alloc(cache, flags); 3509 if (objp) 3510 goto out; 3511 } 3512 objp = ____cache_alloc(cache, flags); 3513 3514 /* 3515 * We may just have run out of memory on the local node. 3516 * ____cache_alloc_node() knows how to locate memory on other nodes 3517 */ 3518 if (!objp) 3519 objp = ____cache_alloc_node(cache, flags, numa_mem_id()); 3520 3521 out: 3522 return objp; 3523} 3524#else 3525 3526static __always_inline void * 3527__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3528{ 3529 return ____cache_alloc(cachep, flags); 3530} 3531 3532#endif /* CONFIG_NUMA */ 3533 3534static __always_inline void * 3535__cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller) 3536{ 3537 unsigned long save_flags; 3538 void *objp; 3539 3540 flags &= gfp_allowed_mask; 3541 3542 lockdep_trace_alloc(flags); 3543 3544 if (slab_should_failslab(cachep, flags)) 3545 return NULL; 3546 3547 cache_alloc_debugcheck_before(cachep, flags); 3548 local_irq_save(save_flags); 3549 objp = __do_cache_alloc(cachep, flags); 3550 local_irq_restore(save_flags); 3551 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); 3552 kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags, 3553 flags); 3554 prefetchw(objp); 3555 3556 if (likely(objp)) 3557 kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep)); 3558 3559 if (unlikely((flags & __GFP_ZERO) && objp)) 3560 memset(objp, 0, obj_size(cachep)); 3561 3562 return objp; 3563} 3564 3565/* 3566 * Caller needs to acquire correct kmem_list's list_lock 3567 */ 3568static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects, 3569 int node) 3570{ 3571 int i; 3572 struct kmem_list3 *l3; 3573 3574 for (i = 0; i < nr_objects; i++) { 3575 void *objp = objpp[i]; 3576 struct slab *slabp; 3577 3578 slabp = virt_to_slab(objp); 3579 l3 = cachep->nodelists[node]; 3580 list_del(&slabp->list); 3581 check_spinlock_acquired_node(cachep, node); 3582 check_slabp(cachep, slabp); 3583 slab_put_obj(cachep, slabp, objp, node); 3584 STATS_DEC_ACTIVE(cachep); 3585 l3->free_objects++; 3586 check_slabp(cachep, slabp); 3587 3588 /* fixup slab chains */ 3589 if (slabp->inuse == 0) { 3590 if (l3->free_objects > l3->free_limit) { 3591 l3->free_objects -= cachep->num; 3592 /* No need to drop any previously held 3593 * lock here, even if we have a off-slab slab 3594 * descriptor it is guaranteed to come from 3595 * a different cache, refer to comments before 3596 * alloc_slabmgmt. 3597 */ 3598 slab_destroy(cachep, slabp); 3599 } else { 3600 list_add(&slabp->list, &l3->slabs_free); 3601 } 3602 } else { 3603 /* Unconditionally move a slab to the end of the 3604 * partial list on free - maximum time for the 3605 * other objects to be freed, too. 3606 */ 3607 list_add_tail(&slabp->list, &l3->slabs_partial); 3608 } 3609 } 3610} 3611 3612static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) 3613{ 3614 int batchcount; 3615 struct kmem_list3 *l3; 3616 int node = numa_mem_id(); 3617 3618 batchcount = ac->batchcount; 3619#if DEBUG 3620 BUG_ON(!batchcount || batchcount > ac->avail); 3621#endif 3622 check_irq_off(); 3623 l3 = cachep->nodelists[node]; 3624 spin_lock(&l3->list_lock); 3625 if (l3->shared) { 3626 struct array_cache *shared_array = l3->shared; 3627 int max = shared_array->limit - shared_array->avail; 3628 if (max) { 3629 if (batchcount > max) 3630 batchcount = max; 3631 memcpy(&(shared_array->entry[shared_array->avail]), 3632 ac->entry, sizeof(void *) * batchcount); 3633 shared_array->avail += batchcount; 3634 goto free_done; 3635 } 3636 } 3637 3638 free_block(cachep, ac->entry, batchcount, node); 3639free_done: 3640#if STATS 3641 { 3642 int i = 0; 3643 struct list_head *p; 3644 3645 p = l3->slabs_free.next; 3646 while (p != &(l3->slabs_free)) { 3647 struct slab *slabp; 3648 3649 slabp = list_entry(p, struct slab, list); 3650 BUG_ON(slabp->inuse); 3651 3652 i++; 3653 p = p->next; 3654 } 3655 STATS_SET_FREEABLE(cachep, i); 3656 } 3657#endif 3658 spin_unlock(&l3->list_lock); 3659 ac->avail -= batchcount; 3660 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); 3661} 3662 3663/* 3664 * Release an obj back to its cache. If the obj has a constructed state, it must 3665 * be in this state _before_ it is released. Called with disabled ints. 3666 */ 3667static inline void __cache_free(struct kmem_cache *cachep, void *objp, 3668 void *caller) 3669{ 3670 struct array_cache *ac = cpu_cache_get(cachep); 3671 3672 check_irq_off(); 3673 kmemleak_free_recursive(objp, cachep->flags); 3674 objp = cache_free_debugcheck(cachep, objp, caller); 3675 3676 kmemcheck_slab_free(cachep, objp, obj_size(cachep)); 3677 3678 /* 3679 * Skip calling cache_free_alien() when the platform is not numa. 3680 * This will avoid cache misses that happen while accessing slabp (which 3681 * is per page memory reference) to get nodeid. Instead use a global 3682 * variable to skip the call, which is mostly likely to be present in 3683 * the cache. 3684 */ 3685 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) 3686 return; 3687 3688 if (likely(ac->avail < ac->limit)) { 3689 STATS_INC_FREEHIT(cachep); 3690 ac->entry[ac->avail++] = objp; 3691 return; 3692 } else { 3693 STATS_INC_FREEMISS(cachep); 3694 cache_flusharray(cachep, ac); 3695 ac->entry[ac->avail++] = objp; 3696 } 3697} 3698 3699/** 3700 * kmem_cache_alloc - Allocate an object 3701 * @cachep: The cache to allocate from. 3702 * @flags: See kmalloc(). 3703 * 3704 * Allocate an object from this cache. The flags are only relevant 3705 * if the cache has no available objects. 3706 */ 3707void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3708{ 3709 void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0)); 3710 3711 trace_kmem_cache_alloc(_RET_IP_, ret, 3712 obj_size(cachep), cachep->buffer_size, flags); 3713 3714 return ret; 3715} 3716EXPORT_SYMBOL(kmem_cache_alloc); 3717 3718#ifdef CONFIG_TRACING 3719void * 3720kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags) 3721{ 3722 void *ret; 3723 3724 ret = __cache_alloc(cachep, flags, __builtin_return_address(0)); 3725 3726 trace_kmalloc(_RET_IP_, ret, 3727 size, slab_buffer_size(cachep), flags); 3728 return ret; 3729} 3730EXPORT_SYMBOL(kmem_cache_alloc_trace); 3731#endif 3732 3733#ifdef CONFIG_NUMA 3734void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) 3735{ 3736 void *ret = __cache_alloc_node(cachep, flags, nodeid, 3737 __builtin_return_address(0)); 3738 3739 trace_kmem_cache_alloc_node(_RET_IP_, ret, 3740 obj_size(cachep), cachep->buffer_size, 3741 flags, nodeid); 3742 3743 return ret; 3744} 3745EXPORT_SYMBOL(kmem_cache_alloc_node); 3746 3747#ifdef CONFIG_TRACING 3748void *kmem_cache_alloc_node_trace(size_t size, 3749 struct kmem_cache *cachep, 3750 gfp_t flags, 3751 int nodeid) 3752{ 3753 void *ret; 3754 3755 ret = __cache_alloc_node(cachep, flags, nodeid, 3756 __builtin_return_address(0)); 3757 trace_kmalloc_node(_RET_IP_, ret, 3758 size, slab_buffer_size(cachep), 3759 flags, nodeid); 3760 return ret; 3761} 3762EXPORT_SYMBOL(kmem_cache_alloc_node_trace); 3763#endif 3764 3765static __always_inline void * 3766__do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller) 3767{ 3768 struct kmem_cache *cachep; 3769 3770 cachep = kmem_find_general_cachep(size, flags); 3771 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3772 return cachep; 3773 return kmem_cache_alloc_node_trace(size, cachep, flags, node); 3774} 3775 3776#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING) 3777void *__kmalloc_node(size_t size, gfp_t flags, int node) 3778{ 3779 return __do_kmalloc_node(size, flags, node, 3780 __builtin_return_address(0)); 3781} 3782EXPORT_SYMBOL(__kmalloc_node); 3783 3784void *__kmalloc_node_track_caller(size_t size, gfp_t flags, 3785 int node, unsigned long caller) 3786{ 3787 return __do_kmalloc_node(size, flags, node, (void *)caller); 3788} 3789EXPORT_SYMBOL(__kmalloc_node_track_caller); 3790#else 3791void *__kmalloc_node(size_t size, gfp_t flags, int node) 3792{ 3793 return __do_kmalloc_node(size, flags, node, NULL); 3794} 3795EXPORT_SYMBOL(__kmalloc_node); 3796#endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */ 3797#endif /* CONFIG_NUMA */ 3798 3799/** 3800 * __do_kmalloc - allocate memory 3801 * @size: how many bytes of memory are required. 3802 * @flags: the type of memory to allocate (see kmalloc). 3803 * @caller: function caller for debug tracking of the caller 3804 */ 3805static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, 3806 void *caller) 3807{ 3808 struct kmem_cache *cachep; 3809 void *ret; 3810 3811 /* If you want to save a few bytes .text space: replace 3812 * __ with kmem_. 3813 * Then kmalloc uses the uninlined functions instead of the inline 3814 * functions. 3815 */ 3816 cachep = __find_general_cachep(size, flags); 3817 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3818 return cachep; 3819 ret = __cache_alloc(cachep, flags, caller); 3820 3821 trace_kmalloc((unsigned long) caller, ret, 3822 size, cachep->buffer_size, flags); 3823 3824 return ret; 3825} 3826 3827 3828#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING) 3829void *__kmalloc(size_t size, gfp_t flags) 3830{ 3831 return __do_kmalloc(size, flags, __builtin_return_address(0)); 3832} 3833EXPORT_SYMBOL(__kmalloc); 3834 3835void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller) 3836{ 3837 return __do_kmalloc(size, flags, (void *)caller); 3838} 3839EXPORT_SYMBOL(__kmalloc_track_caller); 3840 3841#else 3842void *__kmalloc(size_t size, gfp_t flags) 3843{ 3844 return __do_kmalloc(size, flags, NULL); 3845} 3846EXPORT_SYMBOL(__kmalloc); 3847#endif 3848 3849/** 3850 * kmem_cache_free - Deallocate an object 3851 * @cachep: The cache the allocation was from. 3852 * @objp: The previously allocated object. 3853 * 3854 * Free an object which was previously allocated from this 3855 * cache. 3856 */ 3857void kmem_cache_free(struct kmem_cache *cachep, void *objp) 3858{ 3859 unsigned long flags; 3860 3861 local_irq_save(flags); 3862 debug_check_no_locks_freed(objp, obj_size(cachep)); 3863 if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) 3864 debug_check_no_obj_freed(objp, obj_size(cachep)); 3865 __cache_free(cachep, objp, __builtin_return_address(0)); 3866 local_irq_restore(flags); 3867 3868 trace_kmem_cache_free(_RET_IP_, objp); 3869} 3870EXPORT_SYMBOL(kmem_cache_free); 3871 3872/** 3873 * kfree - free previously allocated memory 3874 * @objp: pointer returned by kmalloc. 3875 * 3876 * If @objp is NULL, no operation is performed. 3877 * 3878 * Don't free memory not originally allocated by kmalloc() 3879 * or you will run into trouble. 3880 */ 3881void kfree(const void *objp) 3882{ 3883 struct kmem_cache *c; 3884 unsigned long flags; 3885 3886 trace_kfree(_RET_IP_, objp); 3887 3888 if (unlikely(ZERO_OR_NULL_PTR(objp))) 3889 return; 3890 local_irq_save(flags); 3891 kfree_debugcheck(objp); 3892 c = virt_to_cache(objp); 3893 debug_check_no_locks_freed(objp, obj_size(c)); 3894 debug_check_no_obj_freed(objp, obj_size(c)); 3895 __cache_free(c, (void *)objp, __builtin_return_address(0)); 3896 local_irq_restore(flags); 3897} 3898EXPORT_SYMBOL(kfree); 3899 3900unsigned int kmem_cache_size(struct kmem_cache *cachep) 3901{ 3902 return obj_size(cachep); 3903} 3904EXPORT_SYMBOL(kmem_cache_size); 3905 3906/* 3907 * This initializes kmem_list3 or resizes various caches for all nodes. 3908 */ 3909static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp) 3910{ 3911 int node; 3912 struct kmem_list3 *l3; 3913 struct array_cache *new_shared; 3914 struct array_cache **new_alien = NULL; 3915 3916 for_each_online_node(node) { 3917 3918 if (use_alien_caches) { 3919 new_alien = alloc_alien_cache(node, cachep->limit, gfp); 3920 if (!new_alien) 3921 goto fail; 3922 } 3923 3924 new_shared = NULL; 3925 if (cachep->shared) { 3926 new_shared = alloc_arraycache(node, 3927 cachep->shared*cachep->batchcount, 3928 0xbaadf00d, gfp); 3929 if (!new_shared) { 3930 free_alien_cache(new_alien); 3931 goto fail; 3932 } 3933 } 3934 3935 l3 = cachep->nodelists[node]; 3936 if (l3) { 3937 struct array_cache *shared = l3->shared; 3938 3939 spin_lock_irq(&l3->list_lock); 3940 3941 if (shared) 3942 free_block(cachep, shared->entry, 3943 shared->avail, node); 3944 3945 l3->shared = new_shared; 3946 if (!l3->alien) { 3947 l3->alien = new_alien; 3948 new_alien = NULL; 3949 } 3950 l3->free_limit = (1 + nr_cpus_node(node)) * 3951 cachep->batchcount + cachep->num; 3952 spin_unlock_irq(&l3->list_lock); 3953 kfree(shared); 3954 free_alien_cache(new_alien); 3955 continue; 3956 } 3957 l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node); 3958 if (!l3) { 3959 free_alien_cache(new_alien); 3960 kfree(new_shared); 3961 goto fail; 3962 } 3963 3964 kmem_list3_init(l3); 3965 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 + 3966 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 3967 l3->shared = new_shared; 3968 l3->alien = new_alien; 3969 l3->free_limit = (1 + nr_cpus_node(node)) * 3970 cachep->batchcount + cachep->num; 3971 cachep->nodelists[node] = l3; 3972 } 3973 return 0; 3974 3975fail: 3976 if (!cachep->next.next) { 3977 /* Cache is not active yet. Roll back what we did */ 3978 node--; 3979 while (node >= 0) { 3980 if (cachep->nodelists[node]) { 3981 l3 = cachep->nodelists[node]; 3982 3983 kfree(l3->shared); 3984 free_alien_cache(l3->alien); 3985 kfree(l3); 3986 cachep->nodelists[node] = NULL; 3987 } 3988 node--; 3989 } 3990 } 3991 return -ENOMEM; 3992} 3993 3994struct ccupdate_struct { 3995 struct kmem_cache *cachep; 3996 struct array_cache *new[0]; 3997}; 3998 3999static void do_ccupdate_local(void *info) 4000{ 4001 struct ccupdate_struct *new = info; 4002 struct array_cache *old; 4003 4004 check_irq_off(); 4005 old = cpu_cache_get(new->cachep); 4006 4007 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()]; 4008 new->new[smp_processor_id()] = old; 4009} 4010 4011/* Always called with the cache_chain_mutex held */ 4012static int do_tune_cpucache(struct kmem_cache *cachep, int limit, 4013 int batchcount, int shared, gfp_t gfp) 4014{ 4015 struct ccupdate_struct *new; 4016 int i; 4017 4018 new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *), 4019 gfp); 4020 if (!new) 4021 return -ENOMEM; 4022 4023 for_each_online_cpu(i) { 4024 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit, 4025 batchcount, gfp); 4026 if (!new->new[i]) { 4027 for (i--; i >= 0; i--) 4028 kfree(new->new[i]); 4029 kfree(new); 4030 return -ENOMEM; 4031 } 4032 } 4033 new->cachep = cachep; 4034 4035 on_each_cpu(do_ccupdate_local, (void *)new, 1); 4036 4037 check_irq_on(); 4038 cachep->batchcount = batchcount; 4039 cachep->limit = limit; 4040 cachep->shared = shared; 4041 4042 for_each_online_cpu(i) { 4043 struct array_cache *ccold = new->new[i]; 4044 if (!ccold) 4045 continue; 4046 spin_lock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock); 4047 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i)); 4048 spin_unlock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock); 4049 kfree(ccold); 4050 } 4051 kfree(new); 4052 return alloc_kmemlist(cachep, gfp); 4053} 4054 4055/* Called with cache_chain_mutex held always */ 4056static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) 4057{ 4058 int err; 4059 int limit, shared; 4060 4061 /* 4062 * The head array serves three purposes: 4063 * - create a LIFO ordering, i.e. return objects that are cache-warm 4064 * - reduce the number of spinlock operations. 4065 * - reduce the number of linked list operations on the slab and 4066 * bufctl chains: array operations are cheaper. 4067 * The numbers are guessed, we should auto-tune as described by 4068 * Bonwick. 4069 */ 4070 if (cachep->buffer_size > 131072) 4071 limit = 1; 4072 else if (cachep->buffer_size > PAGE_SIZE) 4073 limit = 8; 4074 else if (cachep->buffer_size > 1024) 4075 limit = 24; 4076 else if (cachep->buffer_size > 256) 4077 limit = 54; 4078 else 4079 limit = 120; 4080 4081 /* 4082 * CPU bound tasks (e.g. network routing) can exhibit cpu bound 4083 * allocation behaviour: Most allocs on one cpu, most free operations 4084 * on another cpu. For these cases, an efficient object passing between 4085 * cpus is necessary. This is provided by a shared array. The array 4086 * replaces Bonwick's magazine layer. 4087 * On uniprocessor, it's functionally equivalent (but less efficient) 4088 * to a larger limit. Thus disabled by default. 4089 */ 4090 shared = 0; 4091 if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1) 4092 shared = 8; 4093 4094#if DEBUG 4095 /* 4096 * With debugging enabled, large batchcount lead to excessively long 4097 * periods with disabled local interrupts. Limit the batchcount 4098 */ 4099 if (limit > 32) 4100 limit = 32; 4101#endif 4102 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared, gfp); 4103 if (err) 4104 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n", 4105 cachep->name, -err); 4106 return err; 4107} 4108 4109/* 4110 * Drain an array if it contains any elements taking the l3 lock only if 4111 * necessary. Note that the l3 listlock also protects the array_cache 4112 * if drain_array() is used on the shared array. 4113 */ 4114static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3, 4115 struct array_cache *ac, int force, int node) 4116{ 4117 int tofree; 4118 4119 if (!ac || !ac->avail) 4120 return; 4121 if (ac->touched && !force) { 4122 ac->touched = 0; 4123 } else { 4124 spin_lock_irq(&l3->list_lock); 4125 if (ac->avail) { 4126 tofree = force ? ac->avail : (ac->limit + 4) / 5; 4127 if (tofree > ac->avail) 4128 tofree = (ac->avail + 1) / 2; 4129 free_block(cachep, ac->entry, tofree, node); 4130 ac->avail -= tofree; 4131 memmove(ac->entry, &(ac->entry[tofree]), 4132 sizeof(void *) * ac->avail); 4133 } 4134 spin_unlock_irq(&l3->list_lock); 4135 } 4136} 4137 4138/** 4139 * cache_reap - Reclaim memory from caches. 4140 * @w: work descriptor 4141 * 4142 * Called from workqueue/eventd every few seconds. 4143 * Purpose: 4144 * - clear the per-cpu caches for this CPU. 4145 * - return freeable pages to the main free memory pool. 4146 * 4147 * If we cannot acquire the cache chain mutex then just give up - we'll try 4148 * again on the next iteration. 4149 */ 4150static void cache_reap(struct work_struct *w) 4151{ 4152 struct kmem_cache *searchp; 4153 struct kmem_list3 *l3; 4154 int node = numa_mem_id(); 4155 struct delayed_work *work = to_delayed_work(w); 4156 4157 if (!mutex_trylock(&cache_chain_mutex)) 4158 /* Give up. Setup the next iteration. */ 4159 goto out; 4160 4161 list_for_each_entry(searchp, &cache_chain, next) { 4162 check_irq_on(); 4163 4164 /* 4165 * We only take the l3 lock if absolutely necessary and we 4166 * have established with reasonable certainty that 4167 * we can do some work if the lock was obtained. 4168 */ 4169 l3 = searchp->nodelists[node]; 4170 4171 reap_alien(searchp, l3); 4172 4173 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node); 4174 4175 /* 4176 * These are racy checks but it does not matter 4177 * if we skip one check or scan twice. 4178 */ 4179 if (time_after(l3->next_reap, jiffies)) 4180 goto next; 4181 4182 l3->next_reap = jiffies + REAPTIMEOUT_LIST3; 4183 4184 drain_array(searchp, l3, l3->shared, 0, node); 4185 4186 if (l3->free_touched) 4187 l3->free_touched = 0; 4188 else { 4189 int freed; 4190 4191 freed = drain_freelist(searchp, l3, (l3->free_limit + 4192 5 * searchp->num - 1) / (5 * searchp->num)); 4193 STATS_ADD_REAPED(searchp, freed); 4194 } 4195next: 4196 cond_resched(); 4197 } 4198 check_irq_on(); 4199 mutex_unlock(&cache_chain_mutex); 4200 next_reap_node(); 4201out: 4202 /* Set up the next iteration */ 4203 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC)); 4204} 4205 4206#ifdef CONFIG_SLABINFO 4207 4208static void print_slabinfo_header(struct seq_file *m) 4209{ 4210 /* 4211 * Output format version, so at least we can change it 4212 * without _too_ many complaints. 4213 */ 4214#if STATS 4215 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 4216#else 4217 seq_puts(m, "slabinfo - version: 2.1\n"); 4218#endif 4219 seq_puts(m, "# name <active_objs> <num_objs> <objsize> " 4220 "<objperslab> <pagesperslab>"); 4221 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 4222 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 4223#if STATS 4224 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> " 4225 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 4226 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 4227#endif 4228 seq_putc(m, '\n'); 4229} 4230 4231static void *s_start(struct seq_file *m, loff_t *pos) 4232{ 4233 loff_t n = *pos; 4234 4235 mutex_lock(&cache_chain_mutex); 4236 if (!n) 4237 print_slabinfo_header(m); 4238 4239 return seq_list_start(&cache_chain, *pos); 4240} 4241 4242static void *s_next(struct seq_file *m, void *p, loff_t *pos) 4243{ 4244 return seq_list_next(p, &cache_chain, pos); 4245} 4246 4247static void s_stop(struct seq_file *m, void *p) 4248{ 4249 mutex_unlock(&cache_chain_mutex); 4250} 4251 4252static int s_show(struct seq_file *m, void *p) 4253{ 4254 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next); 4255 struct slab *slabp; 4256 unsigned long active_objs; 4257 unsigned long num_objs; 4258 unsigned long active_slabs = 0; 4259 unsigned long num_slabs, free_objects = 0, shared_avail = 0; 4260 const char *name; 4261 char *error = NULL; 4262 int node; 4263 struct kmem_list3 *l3; 4264 4265 active_objs = 0; 4266 num_slabs = 0; 4267 for_each_online_node(node) { 4268 l3 = cachep->nodelists[node]; 4269 if (!l3) 4270 continue; 4271 4272 check_irq_on(); 4273 spin_lock_irq(&l3->list_lock); 4274 4275 list_for_each_entry(slabp, &l3->slabs_full, list) { 4276 if (slabp->inuse != cachep->num && !error) 4277 error = "slabs_full accounting error"; 4278 active_objs += cachep->num; 4279 active_slabs++; 4280 } 4281 list_for_each_entry(slabp, &l3->slabs_partial, list) { 4282 if (slabp->inuse == cachep->num && !error) 4283 error = "slabs_partial inuse accounting error"; 4284 if (!slabp->inuse && !error) 4285 error = "slabs_partial/inuse accounting error"; 4286 active_objs += slabp->inuse; 4287 active_slabs++; 4288 } 4289 list_for_each_entry(slabp, &l3->slabs_free, list) { 4290 if (slabp->inuse && !error) 4291 error = "slabs_free/inuse accounting error"; 4292 num_slabs++; 4293 } 4294 free_objects += l3->free_objects; 4295 if (l3->shared) 4296 shared_avail += l3->shared->avail; 4297 4298 spin_unlock_irq(&l3->list_lock); 4299 } 4300 num_slabs += active_slabs; 4301 num_objs = num_slabs * cachep->num; 4302 if (num_objs - active_objs != free_objects && !error) 4303 error = "free_objects accounting error"; 4304 4305 name = cachep->name; 4306 if (error) 4307 printk(KERN_ERR "slab: cache %s error: %s\n", name, error); 4308 4309 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 4310 name, active_objs, num_objs, cachep->buffer_size, 4311 cachep->num, (1 << cachep->gfporder)); 4312 seq_printf(m, " : tunables %4u %4u %4u", 4313 cachep->limit, cachep->batchcount, cachep->shared); 4314 seq_printf(m, " : slabdata %6lu %6lu %6lu", 4315 active_slabs, num_slabs, shared_avail); 4316#if STATS 4317 { /* list3 stats */ 4318 unsigned long high = cachep->high_mark; 4319 unsigned long allocs = cachep->num_allocations; 4320 unsigned long grown = cachep->grown; 4321 unsigned long reaped = cachep->reaped; 4322 unsigned long errors = cachep->errors; 4323 unsigned long max_freeable = cachep->max_freeable; 4324 unsigned long node_allocs = cachep->node_allocs; 4325 unsigned long node_frees = cachep->node_frees; 4326 unsigned long overflows = cachep->node_overflow; 4327 4328 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu " 4329 "%4lu %4lu %4lu %4lu %4lu", 4330 allocs, high, grown, 4331 reaped, errors, max_freeable, node_allocs, 4332 node_frees, overflows); 4333 } 4334 /* cpu stats */ 4335 { 4336 unsigned long allochit = atomic_read(&cachep->allochit); 4337 unsigned long allocmiss = atomic_read(&cachep->allocmiss); 4338 unsigned long freehit = atomic_read(&cachep->freehit); 4339 unsigned long freemiss = atomic_read(&cachep->freemiss); 4340 4341 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", 4342 allochit, allocmiss, freehit, freemiss); 4343 } 4344#endif 4345 seq_putc(m, '\n'); 4346 return 0; 4347} 4348 4349/* 4350 * slabinfo_op - iterator that generates /proc/slabinfo 4351 * 4352 * Output layout: 4353 * cache-name 4354 * num-active-objs 4355 * total-objs 4356 * object size 4357 * num-active-slabs 4358 * total-slabs 4359 * num-pages-per-slab 4360 * + further values on SMP and with statistics enabled 4361 */ 4362 4363static const struct seq_operations slabinfo_op = { 4364 .start = s_start, 4365 .next = s_next, 4366 .stop = s_stop, 4367 .show = s_show, 4368}; 4369 4370#define MAX_SLABINFO_WRITE 128 4371/** 4372 * slabinfo_write - Tuning for the slab allocator 4373 * @file: unused 4374 * @buffer: user buffer 4375 * @count: data length 4376 * @ppos: unused 4377 */ 4378static ssize_t slabinfo_write(struct file *file, const char __user *buffer, 4379 size_t count, loff_t *ppos) 4380{ 4381 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; 4382 int limit, batchcount, shared, res; 4383 struct kmem_cache *cachep; 4384 4385 if (count > MAX_SLABINFO_WRITE) 4386 return -EINVAL; 4387 if (copy_from_user(&kbuf, buffer, count)) 4388 return -EFAULT; 4389 kbuf[MAX_SLABINFO_WRITE] = '\0'; 4390 4391 tmp = strchr(kbuf, ' '); 4392 if (!tmp) 4393 return -EINVAL; 4394 *tmp = '\0'; 4395 tmp++; 4396 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) 4397 return -EINVAL; 4398 4399 /* Find the cache in the chain of caches. */ 4400 mutex_lock(&cache_chain_mutex); 4401 res = -EINVAL; 4402 list_for_each_entry(cachep, &cache_chain, next) { 4403 if (!strcmp(cachep->name, kbuf)) { 4404 if (limit < 1 || batchcount < 1 || 4405 batchcount > limit || shared < 0) { 4406 res = 0; 4407 } else { 4408 res = do_tune_cpucache(cachep, limit, 4409 batchcount, shared, 4410 GFP_KERNEL); 4411 } 4412 break; 4413 } 4414 } 4415 mutex_unlock(&cache_chain_mutex); 4416 if (res >= 0) 4417 res = count; 4418 return res; 4419} 4420 4421static int slabinfo_open(struct inode *inode, struct file *file) 4422{ 4423 return seq_open(file, &slabinfo_op); 4424} 4425 4426static const struct file_operations proc_slabinfo_operations = { 4427 .open = slabinfo_open, 4428 .read = seq_read, 4429 .write = slabinfo_write, 4430 .llseek = seq_lseek, 4431 .release = seq_release, 4432}; 4433 4434#ifdef CONFIG_DEBUG_SLAB_LEAK 4435 4436static void *leaks_start(struct seq_file *m, loff_t *pos) 4437{ 4438 mutex_lock(&cache_chain_mutex); 4439 return seq_list_start(&cache_chain, *pos); 4440} 4441 4442static inline int add_caller(unsigned long *n, unsigned long v) 4443{ 4444 unsigned long *p; 4445 int l; 4446 if (!v) 4447 return 1; 4448 l = n[1]; 4449 p = n + 2; 4450 while (l) { 4451 int i = l/2; 4452 unsigned long *q = p + 2 * i; 4453 if (*q == v) { 4454 q[1]++; 4455 return 1; 4456 } 4457 if (*q > v) { 4458 l = i; 4459 } else { 4460 p = q + 2; 4461 l -= i + 1; 4462 } 4463 } 4464 if (++n[1] == n[0]) 4465 return 0; 4466 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n)); 4467 p[0] = v; 4468 p[1] = 1; 4469 return 1; 4470} 4471 4472static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s) 4473{ 4474 void *p; 4475 int i; 4476 if (n[0] == n[1]) 4477 return; 4478 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) { 4479 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE) 4480 continue; 4481 if (!add_caller(n, (unsigned long)*dbg_userword(c, p))) 4482 return; 4483 } 4484} 4485 4486static void show_symbol(struct seq_file *m, unsigned long address) 4487{ 4488#ifdef CONFIG_KALLSYMS 4489 unsigned long offset, size; 4490 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN]; 4491 4492 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) { 4493 seq_printf(m, "%s+%#lx/%#lx", name, offset, size); 4494 if (modname[0]) 4495 seq_printf(m, " [%s]", modname); 4496 return; 4497 } 4498#endif 4499 seq_printf(m, "%p", (void *)address); 4500} 4501 4502static int leaks_show(struct seq_file *m, void *p) 4503{ 4504 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next); 4505 struct slab *slabp; 4506 struct kmem_list3 *l3; 4507 const char *name; 4508 unsigned long *n = m->private; 4509 int node; 4510 int i; 4511 4512 if (!(cachep->flags & SLAB_STORE_USER)) 4513 return 0; 4514 if (!(cachep->flags & SLAB_RED_ZONE)) 4515 return 0; 4516 4517 /* OK, we can do it */ 4518 4519 n[1] = 0; 4520 4521 for_each_online_node(node) { 4522 l3 = cachep->nodelists[node]; 4523 if (!l3) 4524 continue; 4525 4526 check_irq_on(); 4527 spin_lock_irq(&l3->list_lock); 4528 4529 list_for_each_entry(slabp, &l3->slabs_full, list) 4530 handle_slab(n, cachep, slabp); 4531 list_for_each_entry(slabp, &l3->slabs_partial, list) 4532 handle_slab(n, cachep, slabp); 4533 spin_unlock_irq(&l3->list_lock); 4534 } 4535 name = cachep->name; 4536 if (n[0] == n[1]) { 4537 /* Increase the buffer size */ 4538 mutex_unlock(&cache_chain_mutex); 4539 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL); 4540 if (!m->private) { 4541 /* Too bad, we are really out */ 4542 m->private = n; 4543 mutex_lock(&cache_chain_mutex); 4544 return -ENOMEM; 4545 } 4546 *(unsigned long *)m->private = n[0] * 2; 4547 kfree(n); 4548 mutex_lock(&cache_chain_mutex); 4549 /* Now make sure this entry will be retried */ 4550 m->count = m->size; 4551 return 0; 4552 } 4553 for (i = 0; i < n[1]; i++) { 4554 seq_printf(m, "%s: %lu ", name, n[2*i+3]); 4555 show_symbol(m, n[2*i+2]); 4556 seq_putc(m, '\n'); 4557 } 4558 4559 return 0; 4560} 4561 4562static const struct seq_operations slabstats_op = { 4563 .start = leaks_start, 4564 .next = s_next, 4565 .stop = s_stop, 4566 .show = leaks_show, 4567}; 4568 4569static int slabstats_open(struct inode *inode, struct file *file) 4570{ 4571 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL); 4572 int ret = -ENOMEM; 4573 if (n) { 4574 ret = seq_open(file, &slabstats_op); 4575 if (!ret) { 4576 struct seq_file *m = file->private_data; 4577 *n = PAGE_SIZE / (2 * sizeof(unsigned long)); 4578 m->private = n; 4579 n = NULL; 4580 } 4581 kfree(n); 4582 } 4583 return ret; 4584} 4585 4586static const struct file_operations proc_slabstats_operations = { 4587 .open = slabstats_open, 4588 .read = seq_read, 4589 .llseek = seq_lseek, 4590 .release = seq_release_private, 4591}; 4592#endif 4593 4594static int __init slab_proc_init(void) 4595{ 4596 proc_create("slabinfo",S_IWUSR|S_IRUSR,NULL,&proc_slabinfo_operations); 4597#ifdef CONFIG_DEBUG_SLAB_LEAK 4598 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations); 4599#endif 4600 return 0; 4601} 4602module_init(slab_proc_init); 4603#endif 4604 4605/** 4606 * ksize - get the actual amount of memory allocated for a given object 4607 * @objp: Pointer to the object 4608 * 4609 * kmalloc may internally round up allocations and return more memory 4610 * than requested. ksize() can be used to determine the actual amount of 4611 * memory allocated. The caller may use this additional memory, even though 4612 * a smaller amount of memory was initially specified with the kmalloc call. 4613 * The caller must guarantee that objp points to a valid object previously 4614 * allocated with either kmalloc() or kmem_cache_alloc(). The object 4615 * must not be freed during the duration of the call. 4616 */ 4617size_t ksize(const void *objp) 4618{ 4619 BUG_ON(!objp); 4620 if (unlikely(objp == ZERO_SIZE_PTR)) 4621 return 0; 4622 4623 return obj_size(virt_to_cache(objp)); 4624} 4625EXPORT_SYMBOL(ksize); 4626