slab.c revision 52cef189165d74a5d6030184a8e05595194c69ca
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. 483 */ 484#define BREAK_GFP_ORDER_HI 1 485#define BREAK_GFP_ORDER_LO 0 486static int slab_break_gfp_order = BREAK_GFP_ORDER_LO; 487 488/* 489 * Functions for storing/retrieving the cachep and or slab from the page 490 * allocator. These are used to find the slab an obj belongs to. With kfree(), 491 * these are used to find the cache which an obj belongs to. 492 */ 493static inline void page_set_cache(struct page *page, struct kmem_cache *cache) 494{ 495 page->lru.next = (struct list_head *)cache; 496} 497 498static inline struct kmem_cache *page_get_cache(struct page *page) 499{ 500 page = compound_head(page); 501 BUG_ON(!PageSlab(page)); 502 return (struct kmem_cache *)page->lru.next; 503} 504 505static inline void page_set_slab(struct page *page, struct slab *slab) 506{ 507 page->lru.prev = (struct list_head *)slab; 508} 509 510static inline struct slab *page_get_slab(struct page *page) 511{ 512 BUG_ON(!PageSlab(page)); 513 return (struct slab *)page->lru.prev; 514} 515 516static inline struct kmem_cache *virt_to_cache(const void *obj) 517{ 518 struct page *page = virt_to_head_page(obj); 519 return page_get_cache(page); 520} 521 522static inline struct slab *virt_to_slab(const void *obj) 523{ 524 struct page *page = virt_to_head_page(obj); 525 return page_get_slab(page); 526} 527 528static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab, 529 unsigned int idx) 530{ 531 return slab->s_mem + cache->buffer_size * idx; 532} 533 534/* 535 * We want to avoid an expensive divide : (offset / cache->buffer_size) 536 * Using the fact that buffer_size is a constant for a particular cache, 537 * we can replace (offset / cache->buffer_size) by 538 * reciprocal_divide(offset, cache->reciprocal_buffer_size) 539 */ 540static inline unsigned int obj_to_index(const struct kmem_cache *cache, 541 const struct slab *slab, void *obj) 542{ 543 u32 offset = (obj - slab->s_mem); 544 return reciprocal_divide(offset, cache->reciprocal_buffer_size); 545} 546 547/* 548 * These are the default caches for kmalloc. Custom caches can have other sizes. 549 */ 550struct cache_sizes malloc_sizes[] = { 551#define CACHE(x) { .cs_size = (x) }, 552#include <linux/kmalloc_sizes.h> 553 CACHE(ULONG_MAX) 554#undef CACHE 555}; 556EXPORT_SYMBOL(malloc_sizes); 557 558/* Must match cache_sizes above. Out of line to keep cache footprint low. */ 559struct cache_names { 560 char *name; 561 char *name_dma; 562}; 563 564static struct cache_names __initdata cache_names[] = { 565#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" }, 566#include <linux/kmalloc_sizes.h> 567 {NULL,} 568#undef CACHE 569}; 570 571static struct arraycache_init initarray_cache __initdata = 572 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; 573static struct arraycache_init initarray_generic = 574 { {0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; 575 576/* internal cache of cache description objs */ 577static struct kmem_list3 *cache_cache_nodelists[MAX_NUMNODES]; 578static struct kmem_cache cache_cache = { 579 .nodelists = cache_cache_nodelists, 580 .batchcount = 1, 581 .limit = BOOT_CPUCACHE_ENTRIES, 582 .shared = 1, 583 .buffer_size = sizeof(struct kmem_cache), 584 .name = "kmem_cache", 585}; 586 587#define BAD_ALIEN_MAGIC 0x01020304ul 588 589/* 590 * chicken and egg problem: delay the per-cpu array allocation 591 * until the general caches are up. 592 */ 593static enum { 594 NONE, 595 PARTIAL_AC, 596 PARTIAL_L3, 597 EARLY, 598 LATE, 599 FULL 600} g_cpucache_up; 601 602/* 603 * used by boot code to determine if it can use slab based allocator 604 */ 605int slab_is_available(void) 606{ 607 return g_cpucache_up >= EARLY; 608} 609 610#ifdef CONFIG_LOCKDEP 611 612/* 613 * Slab sometimes uses the kmalloc slabs to store the slab headers 614 * for other slabs "off slab". 615 * The locking for this is tricky in that it nests within the locks 616 * of all other slabs in a few places; to deal with this special 617 * locking we put on-slab caches into a separate lock-class. 618 * 619 * We set lock class for alien array caches which are up during init. 620 * The lock annotation will be lost if all cpus of a node goes down and 621 * then comes back up during hotplug 622 */ 623static struct lock_class_key on_slab_l3_key; 624static struct lock_class_key on_slab_alc_key; 625 626static struct lock_class_key debugobj_l3_key; 627static struct lock_class_key debugobj_alc_key; 628 629static void slab_set_lock_classes(struct kmem_cache *cachep, 630 struct lock_class_key *l3_key, struct lock_class_key *alc_key, 631 int q) 632{ 633 struct array_cache **alc; 634 struct kmem_list3 *l3; 635 int r; 636 637 l3 = cachep->nodelists[q]; 638 if (!l3) 639 return; 640 641 lockdep_set_class(&l3->list_lock, l3_key); 642 alc = l3->alien; 643 /* 644 * FIXME: This check for BAD_ALIEN_MAGIC 645 * should go away when common slab code is taught to 646 * work even without alien caches. 647 * Currently, non NUMA code returns BAD_ALIEN_MAGIC 648 * for alloc_alien_cache, 649 */ 650 if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC) 651 return; 652 for_each_node(r) { 653 if (alc[r]) 654 lockdep_set_class(&alc[r]->lock, alc_key); 655 } 656} 657 658static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node) 659{ 660 slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node); 661} 662 663static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep) 664{ 665 int node; 666 667 for_each_online_node(node) 668 slab_set_debugobj_lock_classes_node(cachep, node); 669} 670 671static void init_node_lock_keys(int q) 672{ 673 struct cache_sizes *s = malloc_sizes; 674 675 if (g_cpucache_up < LATE) 676 return; 677 678 for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) { 679 struct kmem_list3 *l3; 680 681 l3 = s->cs_cachep->nodelists[q]; 682 if (!l3 || OFF_SLAB(s->cs_cachep)) 683 continue; 684 685 slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key, 686 &on_slab_alc_key, q); 687 } 688} 689 690static inline void init_lock_keys(void) 691{ 692 int node; 693 694 for_each_node(node) 695 init_node_lock_keys(node); 696} 697#else 698static void init_node_lock_keys(int q) 699{ 700} 701 702static inline void init_lock_keys(void) 703{ 704} 705 706static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node) 707{ 708} 709 710static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep) 711{ 712} 713#endif 714 715/* 716 * Guard access to the cache-chain. 717 */ 718static DEFINE_MUTEX(cache_chain_mutex); 719static struct list_head cache_chain; 720 721static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); 722 723static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) 724{ 725 return cachep->array[smp_processor_id()]; 726} 727 728static inline struct kmem_cache *__find_general_cachep(size_t size, 729 gfp_t gfpflags) 730{ 731 struct cache_sizes *csizep = malloc_sizes; 732 733#if DEBUG 734 /* This happens if someone tries to call 735 * kmem_cache_create(), or __kmalloc(), before 736 * the generic caches are initialized. 737 */ 738 BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL); 739#endif 740 if (!size) 741 return ZERO_SIZE_PTR; 742 743 while (size > csizep->cs_size) 744 csizep++; 745 746 /* 747 * Really subtle: The last entry with cs->cs_size==ULONG_MAX 748 * has cs_{dma,}cachep==NULL. Thus no special case 749 * for large kmalloc calls required. 750 */ 751#ifdef CONFIG_ZONE_DMA 752 if (unlikely(gfpflags & GFP_DMA)) 753 return csizep->cs_dmacachep; 754#endif 755 return csizep->cs_cachep; 756} 757 758static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags) 759{ 760 return __find_general_cachep(size, gfpflags); 761} 762 763static size_t slab_mgmt_size(size_t nr_objs, size_t align) 764{ 765 return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align); 766} 767 768/* 769 * Calculate the number of objects and left-over bytes for a given buffer size. 770 */ 771static void cache_estimate(unsigned long gfporder, size_t buffer_size, 772 size_t align, int flags, size_t *left_over, 773 unsigned int *num) 774{ 775 int nr_objs; 776 size_t mgmt_size; 777 size_t slab_size = PAGE_SIZE << gfporder; 778 779 /* 780 * The slab management structure can be either off the slab or 781 * on it. For the latter case, the memory allocated for a 782 * slab is used for: 783 * 784 * - The struct slab 785 * - One kmem_bufctl_t for each object 786 * - Padding to respect alignment of @align 787 * - @buffer_size bytes for each object 788 * 789 * If the slab management structure is off the slab, then the 790 * alignment will already be calculated into the size. Because 791 * the slabs are all pages aligned, the objects will be at the 792 * correct alignment when allocated. 793 */ 794 if (flags & CFLGS_OFF_SLAB) { 795 mgmt_size = 0; 796 nr_objs = slab_size / buffer_size; 797 798 if (nr_objs > SLAB_LIMIT) 799 nr_objs = SLAB_LIMIT; 800 } else { 801 /* 802 * Ignore padding for the initial guess. The padding 803 * is at most @align-1 bytes, and @buffer_size is at 804 * least @align. In the worst case, this result will 805 * be one greater than the number of objects that fit 806 * into the memory allocation when taking the padding 807 * into account. 808 */ 809 nr_objs = (slab_size - sizeof(struct slab)) / 810 (buffer_size + sizeof(kmem_bufctl_t)); 811 812 /* 813 * This calculated number will be either the right 814 * amount, or one greater than what we want. 815 */ 816 if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size 817 > slab_size) 818 nr_objs--; 819 820 if (nr_objs > SLAB_LIMIT) 821 nr_objs = SLAB_LIMIT; 822 823 mgmt_size = slab_mgmt_size(nr_objs, align); 824 } 825 *num = nr_objs; 826 *left_over = slab_size - nr_objs*buffer_size - mgmt_size; 827} 828 829#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg) 830 831static void __slab_error(const char *function, struct kmem_cache *cachep, 832 char *msg) 833{ 834 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n", 835 function, cachep->name, msg); 836 dump_stack(); 837} 838 839/* 840 * By default on NUMA we use alien caches to stage the freeing of 841 * objects allocated from other nodes. This causes massive memory 842 * inefficiencies when using fake NUMA setup to split memory into a 843 * large number of small nodes, so it can be disabled on the command 844 * line 845 */ 846 847static int use_alien_caches __read_mostly = 1; 848static int __init noaliencache_setup(char *s) 849{ 850 use_alien_caches = 0; 851 return 1; 852} 853__setup("noaliencache", noaliencache_setup); 854 855#ifdef CONFIG_NUMA 856/* 857 * Special reaping functions for NUMA systems called from cache_reap(). 858 * These take care of doing round robin flushing of alien caches (containing 859 * objects freed on different nodes from which they were allocated) and the 860 * flushing of remote pcps by calling drain_node_pages. 861 */ 862static DEFINE_PER_CPU(unsigned long, slab_reap_node); 863 864static void init_reap_node(int cpu) 865{ 866 int node; 867 868 node = next_node(cpu_to_mem(cpu), node_online_map); 869 if (node == MAX_NUMNODES) 870 node = first_node(node_online_map); 871 872 per_cpu(slab_reap_node, cpu) = node; 873} 874 875static void next_reap_node(void) 876{ 877 int node = __this_cpu_read(slab_reap_node); 878 879 node = next_node(node, node_online_map); 880 if (unlikely(node >= MAX_NUMNODES)) 881 node = first_node(node_online_map); 882 __this_cpu_write(slab_reap_node, node); 883} 884 885#else 886#define init_reap_node(cpu) do { } while (0) 887#define next_reap_node(void) do { } while (0) 888#endif 889 890/* 891 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz 892 * via the workqueue/eventd. 893 * Add the CPU number into the expiration time to minimize the possibility of 894 * the CPUs getting into lockstep and contending for the global cache chain 895 * lock. 896 */ 897static void __cpuinit start_cpu_timer(int cpu) 898{ 899 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu); 900 901 /* 902 * When this gets called from do_initcalls via cpucache_init(), 903 * init_workqueues() has already run, so keventd will be setup 904 * at that time. 905 */ 906 if (keventd_up() && reap_work->work.func == NULL) { 907 init_reap_node(cpu); 908 INIT_DELAYED_WORK_DEFERRABLE(reap_work, cache_reap); 909 schedule_delayed_work_on(cpu, reap_work, 910 __round_jiffies_relative(HZ, cpu)); 911 } 912} 913 914static struct array_cache *alloc_arraycache(int node, int entries, 915 int batchcount, gfp_t gfp) 916{ 917 int memsize = sizeof(void *) * entries + sizeof(struct array_cache); 918 struct array_cache *nc = NULL; 919 920 nc = kmalloc_node(memsize, gfp, node); 921 /* 922 * The array_cache structures contain pointers to free object. 923 * However, when such objects are allocated or transferred to another 924 * cache the pointers are not cleared and they could be counted as 925 * valid references during a kmemleak scan. Therefore, kmemleak must 926 * not scan such objects. 927 */ 928 kmemleak_no_scan(nc); 929 if (nc) { 930 nc->avail = 0; 931 nc->limit = entries; 932 nc->batchcount = batchcount; 933 nc->touched = 0; 934 spin_lock_init(&nc->lock); 935 } 936 return nc; 937} 938 939/* 940 * Transfer objects in one arraycache to another. 941 * Locking must be handled by the caller. 942 * 943 * Return the number of entries transferred. 944 */ 945static int transfer_objects(struct array_cache *to, 946 struct array_cache *from, unsigned int max) 947{ 948 /* Figure out how many entries to transfer */ 949 int nr = min3(from->avail, max, to->limit - to->avail); 950 951 if (!nr) 952 return 0; 953 954 memcpy(to->entry + to->avail, from->entry + from->avail -nr, 955 sizeof(void *) *nr); 956 957 from->avail -= nr; 958 to->avail += nr; 959 return nr; 960} 961 962#ifndef CONFIG_NUMA 963 964#define drain_alien_cache(cachep, alien) do { } while (0) 965#define reap_alien(cachep, l3) do { } while (0) 966 967static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) 968{ 969 return (struct array_cache **)BAD_ALIEN_MAGIC; 970} 971 972static inline void free_alien_cache(struct array_cache **ac_ptr) 973{ 974} 975 976static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 977{ 978 return 0; 979} 980 981static inline void *alternate_node_alloc(struct kmem_cache *cachep, 982 gfp_t flags) 983{ 984 return NULL; 985} 986 987static inline void *____cache_alloc_node(struct kmem_cache *cachep, 988 gfp_t flags, int nodeid) 989{ 990 return NULL; 991} 992 993#else /* CONFIG_NUMA */ 994 995static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int); 996static void *alternate_node_alloc(struct kmem_cache *, gfp_t); 997 998static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) 999{ 1000 struct array_cache **ac_ptr; 1001 int memsize = sizeof(void *) * nr_node_ids; 1002 int i; 1003 1004 if (limit > 1) 1005 limit = 12; 1006 ac_ptr = kzalloc_node(memsize, gfp, node); 1007 if (ac_ptr) { 1008 for_each_node(i) { 1009 if (i == node || !node_online(i)) 1010 continue; 1011 ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp); 1012 if (!ac_ptr[i]) { 1013 for (i--; i >= 0; i--) 1014 kfree(ac_ptr[i]); 1015 kfree(ac_ptr); 1016 return NULL; 1017 } 1018 } 1019 } 1020 return ac_ptr; 1021} 1022 1023static void free_alien_cache(struct array_cache **ac_ptr) 1024{ 1025 int i; 1026 1027 if (!ac_ptr) 1028 return; 1029 for_each_node(i) 1030 kfree(ac_ptr[i]); 1031 kfree(ac_ptr); 1032} 1033 1034static void __drain_alien_cache(struct kmem_cache *cachep, 1035 struct array_cache *ac, int node) 1036{ 1037 struct kmem_list3 *rl3 = cachep->nodelists[node]; 1038 1039 if (ac->avail) { 1040 spin_lock(&rl3->list_lock); 1041 /* 1042 * Stuff objects into the remote nodes shared array first. 1043 * That way we could avoid the overhead of putting the objects 1044 * into the free lists and getting them back later. 1045 */ 1046 if (rl3->shared) 1047 transfer_objects(rl3->shared, ac, ac->limit); 1048 1049 free_block(cachep, ac->entry, ac->avail, node); 1050 ac->avail = 0; 1051 spin_unlock(&rl3->list_lock); 1052 } 1053} 1054 1055/* 1056 * Called from cache_reap() to regularly drain alien caches round robin. 1057 */ 1058static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3) 1059{ 1060 int node = __this_cpu_read(slab_reap_node); 1061 1062 if (l3->alien) { 1063 struct array_cache *ac = l3->alien[node]; 1064 1065 if (ac && ac->avail && spin_trylock_irq(&ac->lock)) { 1066 __drain_alien_cache(cachep, ac, node); 1067 spin_unlock_irq(&ac->lock); 1068 } 1069 } 1070} 1071 1072static void drain_alien_cache(struct kmem_cache *cachep, 1073 struct array_cache **alien) 1074{ 1075 int i = 0; 1076 struct array_cache *ac; 1077 unsigned long flags; 1078 1079 for_each_online_node(i) { 1080 ac = alien[i]; 1081 if (ac) { 1082 spin_lock_irqsave(&ac->lock, flags); 1083 __drain_alien_cache(cachep, ac, i); 1084 spin_unlock_irqrestore(&ac->lock, flags); 1085 } 1086 } 1087} 1088 1089static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 1090{ 1091 struct slab *slabp = virt_to_slab(objp); 1092 int nodeid = slabp->nodeid; 1093 struct kmem_list3 *l3; 1094 struct array_cache *alien = NULL; 1095 int node; 1096 1097 node = numa_mem_id(); 1098 1099 /* 1100 * Make sure we are not freeing a object from another node to the array 1101 * cache on this cpu. 1102 */ 1103 if (likely(slabp->nodeid == node)) 1104 return 0; 1105 1106 l3 = cachep->nodelists[node]; 1107 STATS_INC_NODEFREES(cachep); 1108 if (l3->alien && l3->alien[nodeid]) { 1109 alien = l3->alien[nodeid]; 1110 spin_lock(&alien->lock); 1111 if (unlikely(alien->avail == alien->limit)) { 1112 STATS_INC_ACOVERFLOW(cachep); 1113 __drain_alien_cache(cachep, alien, nodeid); 1114 } 1115 alien->entry[alien->avail++] = objp; 1116 spin_unlock(&alien->lock); 1117 } else { 1118 spin_lock(&(cachep->nodelists[nodeid])->list_lock); 1119 free_block(cachep, &objp, 1, nodeid); 1120 spin_unlock(&(cachep->nodelists[nodeid])->list_lock); 1121 } 1122 return 1; 1123} 1124#endif 1125 1126/* 1127 * Allocates and initializes nodelists for a node on each slab cache, used for 1128 * either memory or cpu hotplug. If memory is being hot-added, the kmem_list3 1129 * will be allocated off-node since memory is not yet online for the new node. 1130 * When hotplugging memory or a cpu, existing nodelists are not replaced if 1131 * already in use. 1132 * 1133 * Must hold cache_chain_mutex. 1134 */ 1135static int init_cache_nodelists_node(int node) 1136{ 1137 struct kmem_cache *cachep; 1138 struct kmem_list3 *l3; 1139 const int memsize = sizeof(struct kmem_list3); 1140 1141 list_for_each_entry(cachep, &cache_chain, next) { 1142 /* 1143 * Set up the size64 kmemlist for cpu before we can 1144 * begin anything. Make sure some other cpu on this 1145 * node has not already allocated this 1146 */ 1147 if (!cachep->nodelists[node]) { 1148 l3 = kmalloc_node(memsize, GFP_KERNEL, node); 1149 if (!l3) 1150 return -ENOMEM; 1151 kmem_list3_init(l3); 1152 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 + 1153 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 1154 1155 /* 1156 * The l3s don't come and go as CPUs come and 1157 * go. cache_chain_mutex is sufficient 1158 * protection here. 1159 */ 1160 cachep->nodelists[node] = l3; 1161 } 1162 1163 spin_lock_irq(&cachep->nodelists[node]->list_lock); 1164 cachep->nodelists[node]->free_limit = 1165 (1 + nr_cpus_node(node)) * 1166 cachep->batchcount + cachep->num; 1167 spin_unlock_irq(&cachep->nodelists[node]->list_lock); 1168 } 1169 return 0; 1170} 1171 1172static void __cpuinit cpuup_canceled(long cpu) 1173{ 1174 struct kmem_cache *cachep; 1175 struct kmem_list3 *l3 = NULL; 1176 int node = cpu_to_mem(cpu); 1177 const struct cpumask *mask = cpumask_of_node(node); 1178 1179 list_for_each_entry(cachep, &cache_chain, next) { 1180 struct array_cache *nc; 1181 struct array_cache *shared; 1182 struct array_cache **alien; 1183 1184 /* cpu is dead; no one can alloc from it. */ 1185 nc = cachep->array[cpu]; 1186 cachep->array[cpu] = NULL; 1187 l3 = cachep->nodelists[node]; 1188 1189 if (!l3) 1190 goto free_array_cache; 1191 1192 spin_lock_irq(&l3->list_lock); 1193 1194 /* Free limit for this kmem_list3 */ 1195 l3->free_limit -= cachep->batchcount; 1196 if (nc) 1197 free_block(cachep, nc->entry, nc->avail, node); 1198 1199 if (!cpumask_empty(mask)) { 1200 spin_unlock_irq(&l3->list_lock); 1201 goto free_array_cache; 1202 } 1203 1204 shared = l3->shared; 1205 if (shared) { 1206 free_block(cachep, shared->entry, 1207 shared->avail, node); 1208 l3->shared = NULL; 1209 } 1210 1211 alien = l3->alien; 1212 l3->alien = NULL; 1213 1214 spin_unlock_irq(&l3->list_lock); 1215 1216 kfree(shared); 1217 if (alien) { 1218 drain_alien_cache(cachep, alien); 1219 free_alien_cache(alien); 1220 } 1221free_array_cache: 1222 kfree(nc); 1223 } 1224 /* 1225 * In the previous loop, all the objects were freed to 1226 * the respective cache's slabs, now we can go ahead and 1227 * shrink each nodelist to its limit. 1228 */ 1229 list_for_each_entry(cachep, &cache_chain, next) { 1230 l3 = cachep->nodelists[node]; 1231 if (!l3) 1232 continue; 1233 drain_freelist(cachep, l3, l3->free_objects); 1234 } 1235} 1236 1237static int __cpuinit cpuup_prepare(long cpu) 1238{ 1239 struct kmem_cache *cachep; 1240 struct kmem_list3 *l3 = NULL; 1241 int node = cpu_to_mem(cpu); 1242 int err; 1243 1244 /* 1245 * We need to do this right in the beginning since 1246 * alloc_arraycache's are going to use this list. 1247 * kmalloc_node allows us to add the slab to the right 1248 * kmem_list3 and not this cpu's kmem_list3 1249 */ 1250 err = init_cache_nodelists_node(node); 1251 if (err < 0) 1252 goto bad; 1253 1254 /* 1255 * Now we can go ahead with allocating the shared arrays and 1256 * array caches 1257 */ 1258 list_for_each_entry(cachep, &cache_chain, next) { 1259 struct array_cache *nc; 1260 struct array_cache *shared = NULL; 1261 struct array_cache **alien = NULL; 1262 1263 nc = alloc_arraycache(node, cachep->limit, 1264 cachep->batchcount, GFP_KERNEL); 1265 if (!nc) 1266 goto bad; 1267 if (cachep->shared) { 1268 shared = alloc_arraycache(node, 1269 cachep->shared * cachep->batchcount, 1270 0xbaadf00d, GFP_KERNEL); 1271 if (!shared) { 1272 kfree(nc); 1273 goto bad; 1274 } 1275 } 1276 if (use_alien_caches) { 1277 alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL); 1278 if (!alien) { 1279 kfree(shared); 1280 kfree(nc); 1281 goto bad; 1282 } 1283 } 1284 cachep->array[cpu] = nc; 1285 l3 = cachep->nodelists[node]; 1286 BUG_ON(!l3); 1287 1288 spin_lock_irq(&l3->list_lock); 1289 if (!l3->shared) { 1290 /* 1291 * We are serialised from CPU_DEAD or 1292 * CPU_UP_CANCELLED by the cpucontrol lock 1293 */ 1294 l3->shared = shared; 1295 shared = NULL; 1296 } 1297#ifdef CONFIG_NUMA 1298 if (!l3->alien) { 1299 l3->alien = alien; 1300 alien = NULL; 1301 } 1302#endif 1303 spin_unlock_irq(&l3->list_lock); 1304 kfree(shared); 1305 free_alien_cache(alien); 1306 if (cachep->flags & SLAB_DEBUG_OBJECTS) 1307 slab_set_debugobj_lock_classes_node(cachep, node); 1308 } 1309 init_node_lock_keys(node); 1310 1311 return 0; 1312bad: 1313 cpuup_canceled(cpu); 1314 return -ENOMEM; 1315} 1316 1317static int __cpuinit cpuup_callback(struct notifier_block *nfb, 1318 unsigned long action, void *hcpu) 1319{ 1320 long cpu = (long)hcpu; 1321 int err = 0; 1322 1323 switch (action) { 1324 case CPU_UP_PREPARE: 1325 case CPU_UP_PREPARE_FROZEN: 1326 mutex_lock(&cache_chain_mutex); 1327 err = cpuup_prepare(cpu); 1328 mutex_unlock(&cache_chain_mutex); 1329 break; 1330 case CPU_ONLINE: 1331 case CPU_ONLINE_FROZEN: 1332 start_cpu_timer(cpu); 1333 break; 1334#ifdef CONFIG_HOTPLUG_CPU 1335 case CPU_DOWN_PREPARE: 1336 case CPU_DOWN_PREPARE_FROZEN: 1337 /* 1338 * Shutdown cache reaper. Note that the cache_chain_mutex is 1339 * held so that if cache_reap() is invoked it cannot do 1340 * anything expensive but will only modify reap_work 1341 * and reschedule the timer. 1342 */ 1343 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu)); 1344 /* Now the cache_reaper is guaranteed to be not running. */ 1345 per_cpu(slab_reap_work, cpu).work.func = NULL; 1346 break; 1347 case CPU_DOWN_FAILED: 1348 case CPU_DOWN_FAILED_FROZEN: 1349 start_cpu_timer(cpu); 1350 break; 1351 case CPU_DEAD: 1352 case CPU_DEAD_FROZEN: 1353 /* 1354 * Even if all the cpus of a node are down, we don't free the 1355 * kmem_list3 of any cache. This to avoid a race between 1356 * cpu_down, and a kmalloc allocation from another cpu for 1357 * memory from the node of the cpu going down. The list3 1358 * structure is usually allocated from kmem_cache_create() and 1359 * gets destroyed at kmem_cache_destroy(). 1360 */ 1361 /* fall through */ 1362#endif 1363 case CPU_UP_CANCELED: 1364 case CPU_UP_CANCELED_FROZEN: 1365 mutex_lock(&cache_chain_mutex); 1366 cpuup_canceled(cpu); 1367 mutex_unlock(&cache_chain_mutex); 1368 break; 1369 } 1370 return notifier_from_errno(err); 1371} 1372 1373static struct notifier_block __cpuinitdata cpucache_notifier = { 1374 &cpuup_callback, NULL, 0 1375}; 1376 1377#if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) 1378/* 1379 * Drains freelist for a node on each slab cache, used for memory hot-remove. 1380 * Returns -EBUSY if all objects cannot be drained so that the node is not 1381 * removed. 1382 * 1383 * Must hold cache_chain_mutex. 1384 */ 1385static int __meminit drain_cache_nodelists_node(int node) 1386{ 1387 struct kmem_cache *cachep; 1388 int ret = 0; 1389 1390 list_for_each_entry(cachep, &cache_chain, next) { 1391 struct kmem_list3 *l3; 1392 1393 l3 = cachep->nodelists[node]; 1394 if (!l3) 1395 continue; 1396 1397 drain_freelist(cachep, l3, l3->free_objects); 1398 1399 if (!list_empty(&l3->slabs_full) || 1400 !list_empty(&l3->slabs_partial)) { 1401 ret = -EBUSY; 1402 break; 1403 } 1404 } 1405 return ret; 1406} 1407 1408static int __meminit slab_memory_callback(struct notifier_block *self, 1409 unsigned long action, void *arg) 1410{ 1411 struct memory_notify *mnb = arg; 1412 int ret = 0; 1413 int nid; 1414 1415 nid = mnb->status_change_nid; 1416 if (nid < 0) 1417 goto out; 1418 1419 switch (action) { 1420 case MEM_GOING_ONLINE: 1421 mutex_lock(&cache_chain_mutex); 1422 ret = init_cache_nodelists_node(nid); 1423 mutex_unlock(&cache_chain_mutex); 1424 break; 1425 case MEM_GOING_OFFLINE: 1426 mutex_lock(&cache_chain_mutex); 1427 ret = drain_cache_nodelists_node(nid); 1428 mutex_unlock(&cache_chain_mutex); 1429 break; 1430 case MEM_ONLINE: 1431 case MEM_OFFLINE: 1432 case MEM_CANCEL_ONLINE: 1433 case MEM_CANCEL_OFFLINE: 1434 break; 1435 } 1436out: 1437 return notifier_from_errno(ret); 1438} 1439#endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */ 1440 1441/* 1442 * swap the static kmem_list3 with kmalloced memory 1443 */ 1444static void __init init_list(struct kmem_cache *cachep, struct kmem_list3 *list, 1445 int nodeid) 1446{ 1447 struct kmem_list3 *ptr; 1448 1449 ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid); 1450 BUG_ON(!ptr); 1451 1452 memcpy(ptr, list, sizeof(struct kmem_list3)); 1453 /* 1454 * Do not assume that spinlocks can be initialized via memcpy: 1455 */ 1456 spin_lock_init(&ptr->list_lock); 1457 1458 MAKE_ALL_LISTS(cachep, ptr, nodeid); 1459 cachep->nodelists[nodeid] = ptr; 1460} 1461 1462/* 1463 * For setting up all the kmem_list3s for cache whose buffer_size is same as 1464 * size of kmem_list3. 1465 */ 1466static void __init set_up_list3s(struct kmem_cache *cachep, int index) 1467{ 1468 int node; 1469 1470 for_each_online_node(node) { 1471 cachep->nodelists[node] = &initkmem_list3[index + node]; 1472 cachep->nodelists[node]->next_reap = jiffies + 1473 REAPTIMEOUT_LIST3 + 1474 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 1475 } 1476} 1477 1478/* 1479 * Initialisation. Called after the page allocator have been initialised and 1480 * before smp_init(). 1481 */ 1482void __init kmem_cache_init(void) 1483{ 1484 size_t left_over; 1485 struct cache_sizes *sizes; 1486 struct cache_names *names; 1487 int i; 1488 int order; 1489 int node; 1490 1491 if (num_possible_nodes() == 1) 1492 use_alien_caches = 0; 1493 1494 for (i = 0; i < NUM_INIT_LISTS; i++) { 1495 kmem_list3_init(&initkmem_list3[i]); 1496 if (i < MAX_NUMNODES) 1497 cache_cache.nodelists[i] = NULL; 1498 } 1499 set_up_list3s(&cache_cache, CACHE_CACHE); 1500 1501 /* 1502 * Fragmentation resistance on low memory - only use bigger 1503 * page orders on machines with more than 32MB of memory. 1504 */ 1505 if (totalram_pages > (32 << 20) >> PAGE_SHIFT) 1506 slab_break_gfp_order = BREAK_GFP_ORDER_HI; 1507 1508 /* Bootstrap is tricky, because several objects are allocated 1509 * from caches that do not exist yet: 1510 * 1) initialize the cache_cache cache: it contains the struct 1511 * kmem_cache structures of all caches, except cache_cache itself: 1512 * cache_cache is statically allocated. 1513 * Initially an __init data area is used for the head array and the 1514 * kmem_list3 structures, it's replaced with a kmalloc allocated 1515 * array at the end of the bootstrap. 1516 * 2) Create the first kmalloc cache. 1517 * The struct kmem_cache for the new cache is allocated normally. 1518 * An __init data area is used for the head array. 1519 * 3) Create the remaining kmalloc caches, with minimally sized 1520 * head arrays. 1521 * 4) Replace the __init data head arrays for cache_cache and the first 1522 * kmalloc cache with kmalloc allocated arrays. 1523 * 5) Replace the __init data for kmem_list3 for cache_cache and 1524 * the other cache's with kmalloc allocated memory. 1525 * 6) Resize the head arrays of the kmalloc caches to their final sizes. 1526 */ 1527 1528 node = numa_mem_id(); 1529 1530 /* 1) create the cache_cache */ 1531 INIT_LIST_HEAD(&cache_chain); 1532 list_add(&cache_cache.next, &cache_chain); 1533 cache_cache.colour_off = cache_line_size(); 1534 cache_cache.array[smp_processor_id()] = &initarray_cache.cache; 1535 cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node]; 1536 1537 /* 1538 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids 1539 */ 1540 cache_cache.buffer_size = offsetof(struct kmem_cache, array[nr_cpu_ids]) + 1541 nr_node_ids * sizeof(struct kmem_list3 *); 1542#if DEBUG 1543 cache_cache.obj_size = cache_cache.buffer_size; 1544#endif 1545 cache_cache.buffer_size = ALIGN(cache_cache.buffer_size, 1546 cache_line_size()); 1547 cache_cache.reciprocal_buffer_size = 1548 reciprocal_value(cache_cache.buffer_size); 1549 1550 for (order = 0; order < MAX_ORDER; order++) { 1551 cache_estimate(order, cache_cache.buffer_size, 1552 cache_line_size(), 0, &left_over, &cache_cache.num); 1553 if (cache_cache.num) 1554 break; 1555 } 1556 BUG_ON(!cache_cache.num); 1557 cache_cache.gfporder = order; 1558 cache_cache.colour = left_over / cache_cache.colour_off; 1559 cache_cache.slab_size = ALIGN(cache_cache.num * sizeof(kmem_bufctl_t) + 1560 sizeof(struct slab), cache_line_size()); 1561 1562 /* 2+3) create the kmalloc caches */ 1563 sizes = malloc_sizes; 1564 names = cache_names; 1565 1566 /* 1567 * Initialize the caches that provide memory for the array cache and the 1568 * kmem_list3 structures first. Without this, further allocations will 1569 * bug. 1570 */ 1571 1572 sizes[INDEX_AC].cs_cachep = kmem_cache_create(names[INDEX_AC].name, 1573 sizes[INDEX_AC].cs_size, 1574 ARCH_KMALLOC_MINALIGN, 1575 ARCH_KMALLOC_FLAGS|SLAB_PANIC, 1576 NULL); 1577 1578 if (INDEX_AC != INDEX_L3) { 1579 sizes[INDEX_L3].cs_cachep = 1580 kmem_cache_create(names[INDEX_L3].name, 1581 sizes[INDEX_L3].cs_size, 1582 ARCH_KMALLOC_MINALIGN, 1583 ARCH_KMALLOC_FLAGS|SLAB_PANIC, 1584 NULL); 1585 } 1586 1587 slab_early_init = 0; 1588 1589 while (sizes->cs_size != ULONG_MAX) { 1590 /* 1591 * For performance, all the general caches are L1 aligned. 1592 * This should be particularly beneficial on SMP boxes, as it 1593 * eliminates "false sharing". 1594 * Note for systems short on memory removing the alignment will 1595 * allow tighter packing of the smaller caches. 1596 */ 1597 if (!sizes->cs_cachep) { 1598 sizes->cs_cachep = kmem_cache_create(names->name, 1599 sizes->cs_size, 1600 ARCH_KMALLOC_MINALIGN, 1601 ARCH_KMALLOC_FLAGS|SLAB_PANIC, 1602 NULL); 1603 } 1604#ifdef CONFIG_ZONE_DMA 1605 sizes->cs_dmacachep = kmem_cache_create( 1606 names->name_dma, 1607 sizes->cs_size, 1608 ARCH_KMALLOC_MINALIGN, 1609 ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA| 1610 SLAB_PANIC, 1611 NULL); 1612#endif 1613 sizes++; 1614 names++; 1615 } 1616 /* 4) Replace the bootstrap head arrays */ 1617 { 1618 struct array_cache *ptr; 1619 1620 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT); 1621 1622 BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache); 1623 memcpy(ptr, cpu_cache_get(&cache_cache), 1624 sizeof(struct arraycache_init)); 1625 /* 1626 * Do not assume that spinlocks can be initialized via memcpy: 1627 */ 1628 spin_lock_init(&ptr->lock); 1629 1630 cache_cache.array[smp_processor_id()] = ptr; 1631 1632 ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT); 1633 1634 BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep) 1635 != &initarray_generic.cache); 1636 memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep), 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 malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] = 1644 ptr; 1645 } 1646 /* 5) Replace the bootstrap kmem_list3's */ 1647 { 1648 int nid; 1649 1650 for_each_online_node(nid) { 1651 init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid); 1652 1653 init_list(malloc_sizes[INDEX_AC].cs_cachep, 1654 &initkmem_list3[SIZE_AC + nid], nid); 1655 1656 if (INDEX_AC != INDEX_L3) { 1657 init_list(malloc_sizes[INDEX_L3].cs_cachep, 1658 &initkmem_list3[SIZE_L3 + nid], nid); 1659 } 1660 } 1661 } 1662 1663 g_cpucache_up = EARLY; 1664} 1665 1666void __init kmem_cache_init_late(void) 1667{ 1668 struct kmem_cache *cachep; 1669 1670 g_cpucache_up = LATE; 1671 1672 /* Annotate slab for lockdep -- annotate the malloc caches */ 1673 init_lock_keys(); 1674 1675 /* 6) resize the head arrays to their final sizes */ 1676 mutex_lock(&cache_chain_mutex); 1677 list_for_each_entry(cachep, &cache_chain, next) 1678 if (enable_cpucache(cachep, GFP_NOWAIT)) 1679 BUG(); 1680 mutex_unlock(&cache_chain_mutex); 1681 1682 /* Done! */ 1683 g_cpucache_up = FULL; 1684 1685 /* 1686 * Register a cpu startup notifier callback that initializes 1687 * cpu_cache_get for all new cpus 1688 */ 1689 register_cpu_notifier(&cpucache_notifier); 1690 1691#ifdef CONFIG_NUMA 1692 /* 1693 * Register a memory hotplug callback that initializes and frees 1694 * nodelists. 1695 */ 1696 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); 1697#endif 1698 1699 /* 1700 * The reap timers are started later, with a module init call: That part 1701 * of the kernel is not yet operational. 1702 */ 1703} 1704 1705static int __init cpucache_init(void) 1706{ 1707 int cpu; 1708 1709 /* 1710 * Register the timers that return unneeded pages to the page allocator 1711 */ 1712 for_each_online_cpu(cpu) 1713 start_cpu_timer(cpu); 1714 return 0; 1715} 1716__initcall(cpucache_init); 1717 1718/* 1719 * Interface to system's page allocator. No need to hold the cache-lock. 1720 * 1721 * If we requested dmaable memory, we will get it. Even if we 1722 * did not request dmaable memory, we might get it, but that 1723 * would be relatively rare and ignorable. 1724 */ 1725static void *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, int nodeid) 1726{ 1727 struct page *page; 1728 int nr_pages; 1729 int i; 1730 1731#ifndef CONFIG_MMU 1732 /* 1733 * Nommu uses slab's for process anonymous memory allocations, and thus 1734 * requires __GFP_COMP to properly refcount higher order allocations 1735 */ 1736 flags |= __GFP_COMP; 1737#endif 1738 1739 flags |= cachep->gfpflags; 1740 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1741 flags |= __GFP_RECLAIMABLE; 1742 1743 page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder); 1744 if (!page) 1745 return NULL; 1746 1747 nr_pages = (1 << cachep->gfporder); 1748 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1749 add_zone_page_state(page_zone(page), 1750 NR_SLAB_RECLAIMABLE, nr_pages); 1751 else 1752 add_zone_page_state(page_zone(page), 1753 NR_SLAB_UNRECLAIMABLE, nr_pages); 1754 for (i = 0; i < nr_pages; i++) 1755 __SetPageSlab(page + i); 1756 1757 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) { 1758 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid); 1759 1760 if (cachep->ctor) 1761 kmemcheck_mark_uninitialized_pages(page, nr_pages); 1762 else 1763 kmemcheck_mark_unallocated_pages(page, nr_pages); 1764 } 1765 1766 return page_address(page); 1767} 1768 1769/* 1770 * Interface to system's page release. 1771 */ 1772static void kmem_freepages(struct kmem_cache *cachep, void *addr) 1773{ 1774 unsigned long i = (1 << cachep->gfporder); 1775 struct page *page = virt_to_page(addr); 1776 const unsigned long nr_freed = i; 1777 1778 kmemcheck_free_shadow(page, cachep->gfporder); 1779 1780 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1781 sub_zone_page_state(page_zone(page), 1782 NR_SLAB_RECLAIMABLE, nr_freed); 1783 else 1784 sub_zone_page_state(page_zone(page), 1785 NR_SLAB_UNRECLAIMABLE, nr_freed); 1786 while (i--) { 1787 BUG_ON(!PageSlab(page)); 1788 __ClearPageSlab(page); 1789 page++; 1790 } 1791 if (current->reclaim_state) 1792 current->reclaim_state->reclaimed_slab += nr_freed; 1793 free_pages((unsigned long)addr, cachep->gfporder); 1794} 1795 1796static void kmem_rcu_free(struct rcu_head *head) 1797{ 1798 struct slab_rcu *slab_rcu = (struct slab_rcu *)head; 1799 struct kmem_cache *cachep = slab_rcu->cachep; 1800 1801 kmem_freepages(cachep, slab_rcu->addr); 1802 if (OFF_SLAB(cachep)) 1803 kmem_cache_free(cachep->slabp_cache, slab_rcu); 1804} 1805 1806#if DEBUG 1807 1808#ifdef CONFIG_DEBUG_PAGEALLOC 1809static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr, 1810 unsigned long caller) 1811{ 1812 int size = obj_size(cachep); 1813 1814 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)]; 1815 1816 if (size < 5 * sizeof(unsigned long)) 1817 return; 1818 1819 *addr++ = 0x12345678; 1820 *addr++ = caller; 1821 *addr++ = smp_processor_id(); 1822 size -= 3 * sizeof(unsigned long); 1823 { 1824 unsigned long *sptr = &caller; 1825 unsigned long svalue; 1826 1827 while (!kstack_end(sptr)) { 1828 svalue = *sptr++; 1829 if (kernel_text_address(svalue)) { 1830 *addr++ = svalue; 1831 size -= sizeof(unsigned long); 1832 if (size <= sizeof(unsigned long)) 1833 break; 1834 } 1835 } 1836 1837 } 1838 *addr++ = 0x87654321; 1839} 1840#endif 1841 1842static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val) 1843{ 1844 int size = obj_size(cachep); 1845 addr = &((char *)addr)[obj_offset(cachep)]; 1846 1847 memset(addr, val, size); 1848 *(unsigned char *)(addr + size - 1) = POISON_END; 1849} 1850 1851static void dump_line(char *data, int offset, int limit) 1852{ 1853 int i; 1854 unsigned char error = 0; 1855 int bad_count = 0; 1856 1857 printk(KERN_ERR "%03x: ", offset); 1858 for (i = 0; i < limit; i++) { 1859 if (data[offset + i] != POISON_FREE) { 1860 error = data[offset + i]; 1861 bad_count++; 1862 } 1863 } 1864 print_hex_dump(KERN_CONT, "", 0, 16, 1, 1865 &data[offset], limit, 1); 1866 1867 if (bad_count == 1) { 1868 error ^= POISON_FREE; 1869 if (!(error & (error - 1))) { 1870 printk(KERN_ERR "Single bit error detected. Probably " 1871 "bad RAM.\n"); 1872#ifdef CONFIG_X86 1873 printk(KERN_ERR "Run memtest86+ or a similar memory " 1874 "test tool.\n"); 1875#else 1876 printk(KERN_ERR "Run a memory test tool.\n"); 1877#endif 1878 } 1879 } 1880} 1881#endif 1882 1883#if DEBUG 1884 1885static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines) 1886{ 1887 int i, size; 1888 char *realobj; 1889 1890 if (cachep->flags & SLAB_RED_ZONE) { 1891 printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\n", 1892 *dbg_redzone1(cachep, objp), 1893 *dbg_redzone2(cachep, objp)); 1894 } 1895 1896 if (cachep->flags & SLAB_STORE_USER) { 1897 printk(KERN_ERR "Last user: [<%p>]", 1898 *dbg_userword(cachep, objp)); 1899 print_symbol("(%s)", 1900 (unsigned long)*dbg_userword(cachep, objp)); 1901 printk("\n"); 1902 } 1903 realobj = (char *)objp + obj_offset(cachep); 1904 size = obj_size(cachep); 1905 for (i = 0; i < size && lines; i += 16, lines--) { 1906 int limit; 1907 limit = 16; 1908 if (i + limit > size) 1909 limit = size - i; 1910 dump_line(realobj, i, limit); 1911 } 1912} 1913 1914static void check_poison_obj(struct kmem_cache *cachep, void *objp) 1915{ 1916 char *realobj; 1917 int size, i; 1918 int lines = 0; 1919 1920 realobj = (char *)objp + obj_offset(cachep); 1921 size = obj_size(cachep); 1922 1923 for (i = 0; i < size; i++) { 1924 char exp = POISON_FREE; 1925 if (i == size - 1) 1926 exp = POISON_END; 1927 if (realobj[i] != exp) { 1928 int limit; 1929 /* Mismatch ! */ 1930 /* Print header */ 1931 if (lines == 0) { 1932 printk(KERN_ERR 1933 "Slab corruption: %s start=%p, len=%d\n", 1934 cachep->name, realobj, size); 1935 print_objinfo(cachep, objp, 0); 1936 } 1937 /* Hexdump the affected line */ 1938 i = (i / 16) * 16; 1939 limit = 16; 1940 if (i + limit > size) 1941 limit = size - i; 1942 dump_line(realobj, i, limit); 1943 i += 16; 1944 lines++; 1945 /* Limit to 5 lines */ 1946 if (lines > 5) 1947 break; 1948 } 1949 } 1950 if (lines != 0) { 1951 /* Print some data about the neighboring objects, if they 1952 * exist: 1953 */ 1954 struct slab *slabp = virt_to_slab(objp); 1955 unsigned int objnr; 1956 1957 objnr = obj_to_index(cachep, slabp, objp); 1958 if (objnr) { 1959 objp = index_to_obj(cachep, slabp, objnr - 1); 1960 realobj = (char *)objp + obj_offset(cachep); 1961 printk(KERN_ERR "Prev obj: start=%p, len=%d\n", 1962 realobj, size); 1963 print_objinfo(cachep, objp, 2); 1964 } 1965 if (objnr + 1 < cachep->num) { 1966 objp = index_to_obj(cachep, slabp, objnr + 1); 1967 realobj = (char *)objp + obj_offset(cachep); 1968 printk(KERN_ERR "Next obj: start=%p, len=%d\n", 1969 realobj, size); 1970 print_objinfo(cachep, objp, 2); 1971 } 1972 } 1973} 1974#endif 1975 1976#if DEBUG 1977static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp) 1978{ 1979 int i; 1980 for (i = 0; i < cachep->num; i++) { 1981 void *objp = index_to_obj(cachep, slabp, i); 1982 1983 if (cachep->flags & SLAB_POISON) { 1984#ifdef CONFIG_DEBUG_PAGEALLOC 1985 if (cachep->buffer_size % PAGE_SIZE == 0 && 1986 OFF_SLAB(cachep)) 1987 kernel_map_pages(virt_to_page(objp), 1988 cachep->buffer_size / PAGE_SIZE, 1); 1989 else 1990 check_poison_obj(cachep, objp); 1991#else 1992 check_poison_obj(cachep, objp); 1993#endif 1994 } 1995 if (cachep->flags & SLAB_RED_ZONE) { 1996 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) 1997 slab_error(cachep, "start of a freed object " 1998 "was overwritten"); 1999 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) 2000 slab_error(cachep, "end of a freed object " 2001 "was overwritten"); 2002 } 2003 } 2004} 2005#else 2006static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp) 2007{ 2008} 2009#endif 2010 2011/** 2012 * slab_destroy - destroy and release all objects in a slab 2013 * @cachep: cache pointer being destroyed 2014 * @slabp: slab pointer being destroyed 2015 * 2016 * Destroy all the objs in a slab, and release the mem back to the system. 2017 * Before calling the slab must have been unlinked from the cache. The 2018 * cache-lock is not held/needed. 2019 */ 2020static void slab_destroy(struct kmem_cache *cachep, struct slab *slabp) 2021{ 2022 void *addr = slabp->s_mem - slabp->colouroff; 2023 2024 slab_destroy_debugcheck(cachep, slabp); 2025 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) { 2026 struct slab_rcu *slab_rcu; 2027 2028 slab_rcu = (struct slab_rcu *)slabp; 2029 slab_rcu->cachep = cachep; 2030 slab_rcu->addr = addr; 2031 call_rcu(&slab_rcu->head, kmem_rcu_free); 2032 } else { 2033 kmem_freepages(cachep, addr); 2034 if (OFF_SLAB(cachep)) 2035 kmem_cache_free(cachep->slabp_cache, slabp); 2036 } 2037} 2038 2039static void __kmem_cache_destroy(struct kmem_cache *cachep) 2040{ 2041 int i; 2042 struct kmem_list3 *l3; 2043 2044 for_each_online_cpu(i) 2045 kfree(cachep->array[i]); 2046 2047 /* NUMA: free the list3 structures */ 2048 for_each_online_node(i) { 2049 l3 = cachep->nodelists[i]; 2050 if (l3) { 2051 kfree(l3->shared); 2052 free_alien_cache(l3->alien); 2053 kfree(l3); 2054 } 2055 } 2056 kmem_cache_free(&cache_cache, cachep); 2057} 2058 2059 2060/** 2061 * calculate_slab_order - calculate size (page order) of slabs 2062 * @cachep: pointer to the cache that is being created 2063 * @size: size of objects to be created in this cache. 2064 * @align: required alignment for the objects. 2065 * @flags: slab allocation flags 2066 * 2067 * Also calculates the number of objects per slab. 2068 * 2069 * This could be made much more intelligent. For now, try to avoid using 2070 * high order pages for slabs. When the gfp() functions are more friendly 2071 * towards high-order requests, this should be changed. 2072 */ 2073static size_t calculate_slab_order(struct kmem_cache *cachep, 2074 size_t size, size_t align, unsigned long flags) 2075{ 2076 unsigned long offslab_limit; 2077 size_t left_over = 0; 2078 int gfporder; 2079 2080 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) { 2081 unsigned int num; 2082 size_t remainder; 2083 2084 cache_estimate(gfporder, size, align, flags, &remainder, &num); 2085 if (!num) 2086 continue; 2087 2088 if (flags & CFLGS_OFF_SLAB) { 2089 /* 2090 * Max number of objs-per-slab for caches which 2091 * use off-slab slabs. Needed to avoid a possible 2092 * looping condition in cache_grow(). 2093 */ 2094 offslab_limit = size - sizeof(struct slab); 2095 offslab_limit /= sizeof(kmem_bufctl_t); 2096 2097 if (num > offslab_limit) 2098 break; 2099 } 2100 2101 /* Found something acceptable - save it away */ 2102 cachep->num = num; 2103 cachep->gfporder = gfporder; 2104 left_over = remainder; 2105 2106 /* 2107 * A VFS-reclaimable slab tends to have most allocations 2108 * as GFP_NOFS and we really don't want to have to be allocating 2109 * higher-order pages when we are unable to shrink dcache. 2110 */ 2111 if (flags & SLAB_RECLAIM_ACCOUNT) 2112 break; 2113 2114 /* 2115 * Large number of objects is good, but very large slabs are 2116 * currently bad for the gfp()s. 2117 */ 2118 if (gfporder >= slab_break_gfp_order) 2119 break; 2120 2121 /* 2122 * Acceptable internal fragmentation? 2123 */ 2124 if (left_over * 8 <= (PAGE_SIZE << gfporder)) 2125 break; 2126 } 2127 return left_over; 2128} 2129 2130static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) 2131{ 2132 if (g_cpucache_up == FULL) 2133 return enable_cpucache(cachep, gfp); 2134 2135 if (g_cpucache_up == NONE) { 2136 /* 2137 * Note: the first kmem_cache_create must create the cache 2138 * that's used by kmalloc(24), otherwise the creation of 2139 * further caches will BUG(). 2140 */ 2141 cachep->array[smp_processor_id()] = &initarray_generic.cache; 2142 2143 /* 2144 * If the cache that's used by kmalloc(sizeof(kmem_list3)) is 2145 * the first cache, then we need to set up all its list3s, 2146 * otherwise the creation of further caches will BUG(). 2147 */ 2148 set_up_list3s(cachep, SIZE_AC); 2149 if (INDEX_AC == INDEX_L3) 2150 g_cpucache_up = PARTIAL_L3; 2151 else 2152 g_cpucache_up = PARTIAL_AC; 2153 } else { 2154 cachep->array[smp_processor_id()] = 2155 kmalloc(sizeof(struct arraycache_init), gfp); 2156 2157 if (g_cpucache_up == PARTIAL_AC) { 2158 set_up_list3s(cachep, SIZE_L3); 2159 g_cpucache_up = PARTIAL_L3; 2160 } else { 2161 int node; 2162 for_each_online_node(node) { 2163 cachep->nodelists[node] = 2164 kmalloc_node(sizeof(struct kmem_list3), 2165 gfp, node); 2166 BUG_ON(!cachep->nodelists[node]); 2167 kmem_list3_init(cachep->nodelists[node]); 2168 } 2169 } 2170 } 2171 cachep->nodelists[numa_mem_id()]->next_reap = 2172 jiffies + REAPTIMEOUT_LIST3 + 2173 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 2174 2175 cpu_cache_get(cachep)->avail = 0; 2176 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES; 2177 cpu_cache_get(cachep)->batchcount = 1; 2178 cpu_cache_get(cachep)->touched = 0; 2179 cachep->batchcount = 1; 2180 cachep->limit = BOOT_CPUCACHE_ENTRIES; 2181 return 0; 2182} 2183 2184/** 2185 * kmem_cache_create - Create a cache. 2186 * @name: A string which is used in /proc/slabinfo to identify this cache. 2187 * @size: The size of objects to be created in this cache. 2188 * @align: The required alignment for the objects. 2189 * @flags: SLAB flags 2190 * @ctor: A constructor for the objects. 2191 * 2192 * Returns a ptr to the cache on success, NULL on failure. 2193 * Cannot be called within a int, but can be interrupted. 2194 * The @ctor is run when new pages are allocated by the cache. 2195 * 2196 * @name must be valid until the cache is destroyed. This implies that 2197 * the module calling this has to destroy the cache before getting unloaded. 2198 * 2199 * The flags are 2200 * 2201 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 2202 * to catch references to uninitialised memory. 2203 * 2204 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 2205 * for buffer overruns. 2206 * 2207 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 2208 * cacheline. This can be beneficial if you're counting cycles as closely 2209 * as davem. 2210 */ 2211struct kmem_cache * 2212kmem_cache_create (const char *name, size_t size, size_t align, 2213 unsigned long flags, void (*ctor)(void *)) 2214{ 2215 size_t left_over, slab_size, ralign; 2216 struct kmem_cache *cachep = NULL, *pc; 2217 gfp_t gfp; 2218 2219 /* 2220 * Sanity checks... these are all serious usage bugs. 2221 */ 2222 if (!name || in_interrupt() || (size < BYTES_PER_WORD) || 2223 size > KMALLOC_MAX_SIZE) { 2224 printk(KERN_ERR "%s: Early error in slab %s\n", __func__, 2225 name); 2226 BUG(); 2227 } 2228 2229 /* 2230 * We use cache_chain_mutex to ensure a consistent view of 2231 * cpu_online_mask as well. Please see cpuup_callback 2232 */ 2233 if (slab_is_available()) { 2234 get_online_cpus(); 2235 mutex_lock(&cache_chain_mutex); 2236 } 2237 2238 list_for_each_entry(pc, &cache_chain, next) { 2239 char tmp; 2240 int res; 2241 2242 /* 2243 * This happens when the module gets unloaded and doesn't 2244 * destroy its slab cache and no-one else reuses the vmalloc 2245 * area of the module. Print a warning. 2246 */ 2247 res = probe_kernel_address(pc->name, tmp); 2248 if (res) { 2249 printk(KERN_ERR 2250 "SLAB: cache with size %d has lost its name\n", 2251 pc->buffer_size); 2252 continue; 2253 } 2254 2255 if (!strcmp(pc->name, name)) { 2256 printk(KERN_ERR 2257 "kmem_cache_create: duplicate cache %s\n", name); 2258 dump_stack(); 2259 goto oops; 2260 } 2261 } 2262 2263#if DEBUG 2264 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 2265#if FORCED_DEBUG 2266 /* 2267 * Enable redzoning and last user accounting, except for caches with 2268 * large objects, if the increased size would increase the object size 2269 * above the next power of two: caches with object sizes just above a 2270 * power of two have a significant amount of internal fragmentation. 2271 */ 2272 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN + 2273 2 * sizeof(unsigned long long))) 2274 flags |= SLAB_RED_ZONE | SLAB_STORE_USER; 2275 if (!(flags & SLAB_DESTROY_BY_RCU)) 2276 flags |= SLAB_POISON; 2277#endif 2278 if (flags & SLAB_DESTROY_BY_RCU) 2279 BUG_ON(flags & SLAB_POISON); 2280#endif 2281 /* 2282 * Always checks flags, a caller might be expecting debug support which 2283 * isn't available. 2284 */ 2285 BUG_ON(flags & ~CREATE_MASK); 2286 2287 /* 2288 * Check that size is in terms of words. This is needed to avoid 2289 * unaligned accesses for some archs when redzoning is used, and makes 2290 * sure any on-slab bufctl's are also correctly aligned. 2291 */ 2292 if (size & (BYTES_PER_WORD - 1)) { 2293 size += (BYTES_PER_WORD - 1); 2294 size &= ~(BYTES_PER_WORD - 1); 2295 } 2296 2297 /* calculate the final buffer alignment: */ 2298 2299 /* 1) arch recommendation: can be overridden for debug */ 2300 if (flags & SLAB_HWCACHE_ALIGN) { 2301 /* 2302 * Default alignment: as specified by the arch code. Except if 2303 * an object is really small, then squeeze multiple objects into 2304 * one cacheline. 2305 */ 2306 ralign = cache_line_size(); 2307 while (size <= ralign / 2) 2308 ralign /= 2; 2309 } else { 2310 ralign = BYTES_PER_WORD; 2311 } 2312 2313 /* 2314 * Redzoning and user store require word alignment or possibly larger. 2315 * Note this will be overridden by architecture or caller mandated 2316 * alignment if either is greater than BYTES_PER_WORD. 2317 */ 2318 if (flags & SLAB_STORE_USER) 2319 ralign = BYTES_PER_WORD; 2320 2321 if (flags & SLAB_RED_ZONE) { 2322 ralign = REDZONE_ALIGN; 2323 /* If redzoning, ensure that the second redzone is suitably 2324 * aligned, by adjusting the object size accordingly. */ 2325 size += REDZONE_ALIGN - 1; 2326 size &= ~(REDZONE_ALIGN - 1); 2327 } 2328 2329 /* 2) arch mandated alignment */ 2330 if (ralign < ARCH_SLAB_MINALIGN) { 2331 ralign = ARCH_SLAB_MINALIGN; 2332 } 2333 /* 3) caller mandated alignment */ 2334 if (ralign < align) { 2335 ralign = align; 2336 } 2337 /* disable debug if necessary */ 2338 if (ralign > __alignof__(unsigned long long)) 2339 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); 2340 /* 2341 * 4) Store it. 2342 */ 2343 align = ralign; 2344 2345 if (slab_is_available()) 2346 gfp = GFP_KERNEL; 2347 else 2348 gfp = GFP_NOWAIT; 2349 2350 /* Get cache's description obj. */ 2351 cachep = kmem_cache_zalloc(&cache_cache, gfp); 2352 if (!cachep) 2353 goto oops; 2354 2355 cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids]; 2356#if DEBUG 2357 cachep->obj_size = size; 2358 2359 /* 2360 * Both debugging options require word-alignment which is calculated 2361 * into align above. 2362 */ 2363 if (flags & SLAB_RED_ZONE) { 2364 /* add space for red zone words */ 2365 cachep->obj_offset += sizeof(unsigned long long); 2366 size += 2 * sizeof(unsigned long long); 2367 } 2368 if (flags & SLAB_STORE_USER) { 2369 /* user store requires one word storage behind the end of 2370 * the real object. But if the second red zone needs to be 2371 * aligned to 64 bits, we must allow that much space. 2372 */ 2373 if (flags & SLAB_RED_ZONE) 2374 size += REDZONE_ALIGN; 2375 else 2376 size += BYTES_PER_WORD; 2377 } 2378#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC) 2379 if (size >= malloc_sizes[INDEX_L3 + 1].cs_size 2380 && cachep->obj_size > cache_line_size() && ALIGN(size, align) < PAGE_SIZE) { 2381 cachep->obj_offset += PAGE_SIZE - ALIGN(size, align); 2382 size = PAGE_SIZE; 2383 } 2384#endif 2385#endif 2386 2387 /* 2388 * Determine if the slab management is 'on' or 'off' slab. 2389 * (bootstrapping cannot cope with offslab caches so don't do 2390 * it too early on. Always use on-slab management when 2391 * SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak) 2392 */ 2393 if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init && 2394 !(flags & SLAB_NOLEAKTRACE)) 2395 /* 2396 * Size is large, assume best to place the slab management obj 2397 * off-slab (should allow better packing of objs). 2398 */ 2399 flags |= CFLGS_OFF_SLAB; 2400 2401 size = ALIGN(size, align); 2402 2403 left_over = calculate_slab_order(cachep, size, align, flags); 2404 2405 if (!cachep->num) { 2406 printk(KERN_ERR 2407 "kmem_cache_create: couldn't create cache %s.\n", name); 2408 kmem_cache_free(&cache_cache, cachep); 2409 cachep = NULL; 2410 goto oops; 2411 } 2412 slab_size = ALIGN(cachep->num * sizeof(kmem_bufctl_t) 2413 + sizeof(struct slab), align); 2414 2415 /* 2416 * If the slab has been placed off-slab, and we have enough space then 2417 * move it on-slab. This is at the expense of any extra colouring. 2418 */ 2419 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) { 2420 flags &= ~CFLGS_OFF_SLAB; 2421 left_over -= slab_size; 2422 } 2423 2424 if (flags & CFLGS_OFF_SLAB) { 2425 /* really off slab. No need for manual alignment */ 2426 slab_size = 2427 cachep->num * sizeof(kmem_bufctl_t) + sizeof(struct slab); 2428 2429#ifdef CONFIG_PAGE_POISONING 2430 /* If we're going to use the generic kernel_map_pages() 2431 * poisoning, then it's going to smash the contents of 2432 * the redzone and userword anyhow, so switch them off. 2433 */ 2434 if (size % PAGE_SIZE == 0 && flags & SLAB_POISON) 2435 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); 2436#endif 2437 } 2438 2439 cachep->colour_off = cache_line_size(); 2440 /* Offset must be a multiple of the alignment. */ 2441 if (cachep->colour_off < align) 2442 cachep->colour_off = align; 2443 cachep->colour = left_over / cachep->colour_off; 2444 cachep->slab_size = slab_size; 2445 cachep->flags = flags; 2446 cachep->gfpflags = 0; 2447 if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA)) 2448 cachep->gfpflags |= GFP_DMA; 2449 cachep->buffer_size = size; 2450 cachep->reciprocal_buffer_size = reciprocal_value(size); 2451 2452 if (flags & CFLGS_OFF_SLAB) { 2453 cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u); 2454 /* 2455 * This is a possibility for one of the malloc_sizes caches. 2456 * But since we go off slab only for object size greater than 2457 * PAGE_SIZE/8, and malloc_sizes gets created in ascending order, 2458 * this should not happen at all. 2459 * But leave a BUG_ON for some lucky dude. 2460 */ 2461 BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache)); 2462 } 2463 cachep->ctor = ctor; 2464 cachep->name = name; 2465 2466 if (setup_cpu_cache(cachep, gfp)) { 2467 __kmem_cache_destroy(cachep); 2468 cachep = NULL; 2469 goto oops; 2470 } 2471 2472 if (flags & SLAB_DEBUG_OBJECTS) { 2473 /* 2474 * Would deadlock through slab_destroy()->call_rcu()-> 2475 * debug_object_activate()->kmem_cache_alloc(). 2476 */ 2477 WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU); 2478 2479 slab_set_debugobj_lock_classes(cachep); 2480 } 2481 2482 /* cache setup completed, link it into the list */ 2483 list_add(&cachep->next, &cache_chain); 2484oops: 2485 if (!cachep && (flags & SLAB_PANIC)) 2486 panic("kmem_cache_create(): failed to create slab `%s'\n", 2487 name); 2488 if (slab_is_available()) { 2489 mutex_unlock(&cache_chain_mutex); 2490 put_online_cpus(); 2491 } 2492 return cachep; 2493} 2494EXPORT_SYMBOL(kmem_cache_create); 2495 2496#if DEBUG 2497static void check_irq_off(void) 2498{ 2499 BUG_ON(!irqs_disabled()); 2500} 2501 2502static void check_irq_on(void) 2503{ 2504 BUG_ON(irqs_disabled()); 2505} 2506 2507static void check_spinlock_acquired(struct kmem_cache *cachep) 2508{ 2509#ifdef CONFIG_SMP 2510 check_irq_off(); 2511 assert_spin_locked(&cachep->nodelists[numa_mem_id()]->list_lock); 2512#endif 2513} 2514 2515static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) 2516{ 2517#ifdef CONFIG_SMP 2518 check_irq_off(); 2519 assert_spin_locked(&cachep->nodelists[node]->list_lock); 2520#endif 2521} 2522 2523#else 2524#define check_irq_off() do { } while(0) 2525#define check_irq_on() do { } while(0) 2526#define check_spinlock_acquired(x) do { } while(0) 2527#define check_spinlock_acquired_node(x, y) do { } while(0) 2528#endif 2529 2530static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3, 2531 struct array_cache *ac, 2532 int force, int node); 2533 2534static void do_drain(void *arg) 2535{ 2536 struct kmem_cache *cachep = arg; 2537 struct array_cache *ac; 2538 int node = numa_mem_id(); 2539 2540 check_irq_off(); 2541 ac = cpu_cache_get(cachep); 2542 spin_lock(&cachep->nodelists[node]->list_lock); 2543 free_block(cachep, ac->entry, ac->avail, node); 2544 spin_unlock(&cachep->nodelists[node]->list_lock); 2545 ac->avail = 0; 2546} 2547 2548static void drain_cpu_caches(struct kmem_cache *cachep) 2549{ 2550 struct kmem_list3 *l3; 2551 int node; 2552 2553 on_each_cpu(do_drain, cachep, 1); 2554 check_irq_on(); 2555 for_each_online_node(node) { 2556 l3 = cachep->nodelists[node]; 2557 if (l3 && l3->alien) 2558 drain_alien_cache(cachep, l3->alien); 2559 } 2560 2561 for_each_online_node(node) { 2562 l3 = cachep->nodelists[node]; 2563 if (l3) 2564 drain_array(cachep, l3, l3->shared, 1, node); 2565 } 2566} 2567 2568/* 2569 * Remove slabs from the list of free slabs. 2570 * Specify the number of slabs to drain in tofree. 2571 * 2572 * Returns the actual number of slabs released. 2573 */ 2574static int drain_freelist(struct kmem_cache *cache, 2575 struct kmem_list3 *l3, int tofree) 2576{ 2577 struct list_head *p; 2578 int nr_freed; 2579 struct slab *slabp; 2580 2581 nr_freed = 0; 2582 while (nr_freed < tofree && !list_empty(&l3->slabs_free)) { 2583 2584 spin_lock_irq(&l3->list_lock); 2585 p = l3->slabs_free.prev; 2586 if (p == &l3->slabs_free) { 2587 spin_unlock_irq(&l3->list_lock); 2588 goto out; 2589 } 2590 2591 slabp = list_entry(p, struct slab, list); 2592#if DEBUG 2593 BUG_ON(slabp->inuse); 2594#endif 2595 list_del(&slabp->list); 2596 /* 2597 * Safe to drop the lock. The slab is no longer linked 2598 * to the cache. 2599 */ 2600 l3->free_objects -= cache->num; 2601 spin_unlock_irq(&l3->list_lock); 2602 slab_destroy(cache, slabp); 2603 nr_freed++; 2604 } 2605out: 2606 return nr_freed; 2607} 2608 2609/* Called with cache_chain_mutex held to protect against cpu hotplug */ 2610static int __cache_shrink(struct kmem_cache *cachep) 2611{ 2612 int ret = 0, i = 0; 2613 struct kmem_list3 *l3; 2614 2615 drain_cpu_caches(cachep); 2616 2617 check_irq_on(); 2618 for_each_online_node(i) { 2619 l3 = cachep->nodelists[i]; 2620 if (!l3) 2621 continue; 2622 2623 drain_freelist(cachep, l3, l3->free_objects); 2624 2625 ret += !list_empty(&l3->slabs_full) || 2626 !list_empty(&l3->slabs_partial); 2627 } 2628 return (ret ? 1 : 0); 2629} 2630 2631/** 2632 * kmem_cache_shrink - Shrink a cache. 2633 * @cachep: The cache to shrink. 2634 * 2635 * Releases as many slabs as possible for a cache. 2636 * To help debugging, a zero exit status indicates all slabs were released. 2637 */ 2638int kmem_cache_shrink(struct kmem_cache *cachep) 2639{ 2640 int ret; 2641 BUG_ON(!cachep || in_interrupt()); 2642 2643 get_online_cpus(); 2644 mutex_lock(&cache_chain_mutex); 2645 ret = __cache_shrink(cachep); 2646 mutex_unlock(&cache_chain_mutex); 2647 put_online_cpus(); 2648 return ret; 2649} 2650EXPORT_SYMBOL(kmem_cache_shrink); 2651 2652/** 2653 * kmem_cache_destroy - delete a cache 2654 * @cachep: the cache to destroy 2655 * 2656 * Remove a &struct kmem_cache object from the slab cache. 2657 * 2658 * It is expected this function will be called by a module when it is 2659 * unloaded. This will remove the cache completely, and avoid a duplicate 2660 * cache being allocated each time a module is loaded and unloaded, if the 2661 * module doesn't have persistent in-kernel storage across loads and unloads. 2662 * 2663 * The cache must be empty before calling this function. 2664 * 2665 * The caller must guarantee that no one will allocate memory from the cache 2666 * during the kmem_cache_destroy(). 2667 */ 2668void kmem_cache_destroy(struct kmem_cache *cachep) 2669{ 2670 BUG_ON(!cachep || in_interrupt()); 2671 2672 /* Find the cache in the chain of caches. */ 2673 get_online_cpus(); 2674 mutex_lock(&cache_chain_mutex); 2675 /* 2676 * the chain is never empty, cache_cache is never destroyed 2677 */ 2678 list_del(&cachep->next); 2679 if (__cache_shrink(cachep)) { 2680 slab_error(cachep, "Can't free all objects"); 2681 list_add(&cachep->next, &cache_chain); 2682 mutex_unlock(&cache_chain_mutex); 2683 put_online_cpus(); 2684 return; 2685 } 2686 2687 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) 2688 rcu_barrier(); 2689 2690 __kmem_cache_destroy(cachep); 2691 mutex_unlock(&cache_chain_mutex); 2692 put_online_cpus(); 2693} 2694EXPORT_SYMBOL(kmem_cache_destroy); 2695 2696/* 2697 * Get the memory for a slab management obj. 2698 * For a slab cache when the slab descriptor is off-slab, slab descriptors 2699 * always come from malloc_sizes caches. The slab descriptor cannot 2700 * come from the same cache which is getting created because, 2701 * when we are searching for an appropriate cache for these 2702 * descriptors in kmem_cache_create, we search through the malloc_sizes array. 2703 * If we are creating a malloc_sizes cache here it would not be visible to 2704 * kmem_find_general_cachep till the initialization is complete. 2705 * Hence we cannot have slabp_cache same as the original cache. 2706 */ 2707static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp, 2708 int colour_off, gfp_t local_flags, 2709 int nodeid) 2710{ 2711 struct slab *slabp; 2712 2713 if (OFF_SLAB(cachep)) { 2714 /* Slab management obj is off-slab. */ 2715 slabp = kmem_cache_alloc_node(cachep->slabp_cache, 2716 local_flags, nodeid); 2717 /* 2718 * If the first object in the slab is leaked (it's allocated 2719 * but no one has a reference to it), we want to make sure 2720 * kmemleak does not treat the ->s_mem pointer as a reference 2721 * to the object. Otherwise we will not report the leak. 2722 */ 2723 kmemleak_scan_area(&slabp->list, sizeof(struct list_head), 2724 local_flags); 2725 if (!slabp) 2726 return NULL; 2727 } else { 2728 slabp = objp + colour_off; 2729 colour_off += cachep->slab_size; 2730 } 2731 slabp->inuse = 0; 2732 slabp->colouroff = colour_off; 2733 slabp->s_mem = objp + colour_off; 2734 slabp->nodeid = nodeid; 2735 slabp->free = 0; 2736 return slabp; 2737} 2738 2739static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp) 2740{ 2741 return (kmem_bufctl_t *) (slabp + 1); 2742} 2743 2744static void cache_init_objs(struct kmem_cache *cachep, 2745 struct slab *slabp) 2746{ 2747 int i; 2748 2749 for (i = 0; i < cachep->num; i++) { 2750 void *objp = index_to_obj(cachep, slabp, i); 2751#if DEBUG 2752 /* need to poison the objs? */ 2753 if (cachep->flags & SLAB_POISON) 2754 poison_obj(cachep, objp, POISON_FREE); 2755 if (cachep->flags & SLAB_STORE_USER) 2756 *dbg_userword(cachep, objp) = NULL; 2757 2758 if (cachep->flags & SLAB_RED_ZONE) { 2759 *dbg_redzone1(cachep, objp) = RED_INACTIVE; 2760 *dbg_redzone2(cachep, objp) = RED_INACTIVE; 2761 } 2762 /* 2763 * Constructors are not allowed to allocate memory from the same 2764 * cache which they are a constructor for. Otherwise, deadlock. 2765 * They must also be threaded. 2766 */ 2767 if (cachep->ctor && !(cachep->flags & SLAB_POISON)) 2768 cachep->ctor(objp + obj_offset(cachep)); 2769 2770 if (cachep->flags & SLAB_RED_ZONE) { 2771 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) 2772 slab_error(cachep, "constructor overwrote the" 2773 " end of an object"); 2774 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) 2775 slab_error(cachep, "constructor overwrote the" 2776 " start of an object"); 2777 } 2778 if ((cachep->buffer_size % PAGE_SIZE) == 0 && 2779 OFF_SLAB(cachep) && cachep->flags & SLAB_POISON) 2780 kernel_map_pages(virt_to_page(objp), 2781 cachep->buffer_size / PAGE_SIZE, 0); 2782#else 2783 if (cachep->ctor) 2784 cachep->ctor(objp); 2785#endif 2786 slab_bufctl(slabp)[i] = i + 1; 2787 } 2788 slab_bufctl(slabp)[i - 1] = BUFCTL_END; 2789} 2790 2791static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags) 2792{ 2793 if (CONFIG_ZONE_DMA_FLAG) { 2794 if (flags & GFP_DMA) 2795 BUG_ON(!(cachep->gfpflags & GFP_DMA)); 2796 else 2797 BUG_ON(cachep->gfpflags & GFP_DMA); 2798 } 2799} 2800 2801static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp, 2802 int nodeid) 2803{ 2804 void *objp = index_to_obj(cachep, slabp, slabp->free); 2805 kmem_bufctl_t next; 2806 2807 slabp->inuse++; 2808 next = slab_bufctl(slabp)[slabp->free]; 2809#if DEBUG 2810 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE; 2811 WARN_ON(slabp->nodeid != nodeid); 2812#endif 2813 slabp->free = next; 2814 2815 return objp; 2816} 2817 2818static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp, 2819 void *objp, int nodeid) 2820{ 2821 unsigned int objnr = obj_to_index(cachep, slabp, objp); 2822 2823#if DEBUG 2824 /* Verify that the slab belongs to the intended node */ 2825 WARN_ON(slabp->nodeid != nodeid); 2826 2827 if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) { 2828 printk(KERN_ERR "slab: double free detected in cache " 2829 "'%s', objp %p\n", cachep->name, objp); 2830 BUG(); 2831 } 2832#endif 2833 slab_bufctl(slabp)[objnr] = slabp->free; 2834 slabp->free = objnr; 2835 slabp->inuse--; 2836} 2837 2838/* 2839 * Map pages beginning at addr to the given cache and slab. This is required 2840 * for the slab allocator to be able to lookup the cache and slab of a 2841 * virtual address for kfree, ksize, and slab debugging. 2842 */ 2843static void slab_map_pages(struct kmem_cache *cache, struct slab *slab, 2844 void *addr) 2845{ 2846 int nr_pages; 2847 struct page *page; 2848 2849 page = virt_to_page(addr); 2850 2851 nr_pages = 1; 2852 if (likely(!PageCompound(page))) 2853 nr_pages <<= cache->gfporder; 2854 2855 do { 2856 page_set_cache(page, cache); 2857 page_set_slab(page, slab); 2858 page++; 2859 } while (--nr_pages); 2860} 2861 2862/* 2863 * Grow (by 1) the number of slabs within a cache. This is called by 2864 * kmem_cache_alloc() when there are no active objs left in a cache. 2865 */ 2866static int cache_grow(struct kmem_cache *cachep, 2867 gfp_t flags, int nodeid, void *objp) 2868{ 2869 struct slab *slabp; 2870 size_t offset; 2871 gfp_t local_flags; 2872 struct kmem_list3 *l3; 2873 2874 /* 2875 * Be lazy and only check for valid flags here, keeping it out of the 2876 * critical path in kmem_cache_alloc(). 2877 */ 2878 BUG_ON(flags & GFP_SLAB_BUG_MASK); 2879 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); 2880 2881 /* Take the l3 list lock to change the colour_next on this node */ 2882 check_irq_off(); 2883 l3 = cachep->nodelists[nodeid]; 2884 spin_lock(&l3->list_lock); 2885 2886 /* Get colour for the slab, and cal the next value. */ 2887 offset = l3->colour_next; 2888 l3->colour_next++; 2889 if (l3->colour_next >= cachep->colour) 2890 l3->colour_next = 0; 2891 spin_unlock(&l3->list_lock); 2892 2893 offset *= cachep->colour_off; 2894 2895 if (local_flags & __GFP_WAIT) 2896 local_irq_enable(); 2897 2898 /* 2899 * The test for missing atomic flag is performed here, rather than 2900 * the more obvious place, simply to reduce the critical path length 2901 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they 2902 * will eventually be caught here (where it matters). 2903 */ 2904 kmem_flagcheck(cachep, flags); 2905 2906 /* 2907 * Get mem for the objs. Attempt to allocate a physical page from 2908 * 'nodeid'. 2909 */ 2910 if (!objp) 2911 objp = kmem_getpages(cachep, local_flags, nodeid); 2912 if (!objp) 2913 goto failed; 2914 2915 /* Get slab management. */ 2916 slabp = alloc_slabmgmt(cachep, objp, offset, 2917 local_flags & ~GFP_CONSTRAINT_MASK, nodeid); 2918 if (!slabp) 2919 goto opps1; 2920 2921 slab_map_pages(cachep, slabp, objp); 2922 2923 cache_init_objs(cachep, slabp); 2924 2925 if (local_flags & __GFP_WAIT) 2926 local_irq_disable(); 2927 check_irq_off(); 2928 spin_lock(&l3->list_lock); 2929 2930 /* Make slab active. */ 2931 list_add_tail(&slabp->list, &(l3->slabs_free)); 2932 STATS_INC_GROWN(cachep); 2933 l3->free_objects += cachep->num; 2934 spin_unlock(&l3->list_lock); 2935 return 1; 2936opps1: 2937 kmem_freepages(cachep, objp); 2938failed: 2939 if (local_flags & __GFP_WAIT) 2940 local_irq_disable(); 2941 return 0; 2942} 2943 2944#if DEBUG 2945 2946/* 2947 * Perform extra freeing checks: 2948 * - detect bad pointers. 2949 * - POISON/RED_ZONE checking 2950 */ 2951static void kfree_debugcheck(const void *objp) 2952{ 2953 if (!virt_addr_valid(objp)) { 2954 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n", 2955 (unsigned long)objp); 2956 BUG(); 2957 } 2958} 2959 2960static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) 2961{ 2962 unsigned long long redzone1, redzone2; 2963 2964 redzone1 = *dbg_redzone1(cache, obj); 2965 redzone2 = *dbg_redzone2(cache, obj); 2966 2967 /* 2968 * Redzone is ok. 2969 */ 2970 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE) 2971 return; 2972 2973 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE) 2974 slab_error(cache, "double free detected"); 2975 else 2976 slab_error(cache, "memory outside object was overwritten"); 2977 2978 printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n", 2979 obj, redzone1, redzone2); 2980} 2981 2982static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, 2983 void *caller) 2984{ 2985 struct page *page; 2986 unsigned int objnr; 2987 struct slab *slabp; 2988 2989 BUG_ON(virt_to_cache(objp) != cachep); 2990 2991 objp -= obj_offset(cachep); 2992 kfree_debugcheck(objp); 2993 page = virt_to_head_page(objp); 2994 2995 slabp = page_get_slab(page); 2996 2997 if (cachep->flags & SLAB_RED_ZONE) { 2998 verify_redzone_free(cachep, objp); 2999 *dbg_redzone1(cachep, objp) = RED_INACTIVE; 3000 *dbg_redzone2(cachep, objp) = RED_INACTIVE; 3001 } 3002 if (cachep->flags & SLAB_STORE_USER) 3003 *dbg_userword(cachep, objp) = caller; 3004 3005 objnr = obj_to_index(cachep, slabp, objp); 3006 3007 BUG_ON(objnr >= cachep->num); 3008 BUG_ON(objp != index_to_obj(cachep, slabp, objnr)); 3009 3010#ifdef CONFIG_DEBUG_SLAB_LEAK 3011 slab_bufctl(slabp)[objnr] = BUFCTL_FREE; 3012#endif 3013 if (cachep->flags & SLAB_POISON) { 3014#ifdef CONFIG_DEBUG_PAGEALLOC 3015 if ((cachep->buffer_size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) { 3016 store_stackinfo(cachep, objp, (unsigned long)caller); 3017 kernel_map_pages(virt_to_page(objp), 3018 cachep->buffer_size / PAGE_SIZE, 0); 3019 } else { 3020 poison_obj(cachep, objp, POISON_FREE); 3021 } 3022#else 3023 poison_obj(cachep, objp, POISON_FREE); 3024#endif 3025 } 3026 return objp; 3027} 3028 3029static void check_slabp(struct kmem_cache *cachep, struct slab *slabp) 3030{ 3031 kmem_bufctl_t i; 3032 int entries = 0; 3033 3034 /* Check slab's freelist to see if this obj is there. */ 3035 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) { 3036 entries++; 3037 if (entries > cachep->num || i >= cachep->num) 3038 goto bad; 3039 } 3040 if (entries != cachep->num - slabp->inuse) { 3041bad: 3042 printk(KERN_ERR "slab: Internal list corruption detected in " 3043 "cache '%s'(%d), slabp %p(%d). Hexdump:\n", 3044 cachep->name, cachep->num, slabp, slabp->inuse); 3045 print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp, 3046 sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t), 3047 1); 3048 BUG(); 3049 } 3050} 3051#else 3052#define kfree_debugcheck(x) do { } while(0) 3053#define cache_free_debugcheck(x,objp,z) (objp) 3054#define check_slabp(x,y) do { } while(0) 3055#endif 3056 3057static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) 3058{ 3059 int batchcount; 3060 struct kmem_list3 *l3; 3061 struct array_cache *ac; 3062 int node; 3063 3064retry: 3065 check_irq_off(); 3066 node = numa_mem_id(); 3067 ac = cpu_cache_get(cachep); 3068 batchcount = ac->batchcount; 3069 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { 3070 /* 3071 * If there was little recent activity on this cache, then 3072 * perform only a partial refill. Otherwise we could generate 3073 * refill bouncing. 3074 */ 3075 batchcount = BATCHREFILL_LIMIT; 3076 } 3077 l3 = cachep->nodelists[node]; 3078 3079 BUG_ON(ac->avail > 0 || !l3); 3080 spin_lock(&l3->list_lock); 3081 3082 /* See if we can refill from the shared array */ 3083 if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) { 3084 l3->shared->touched = 1; 3085 goto alloc_done; 3086 } 3087 3088 while (batchcount > 0) { 3089 struct list_head *entry; 3090 struct slab *slabp; 3091 /* Get slab alloc is to come from. */ 3092 entry = l3->slabs_partial.next; 3093 if (entry == &l3->slabs_partial) { 3094 l3->free_touched = 1; 3095 entry = l3->slabs_free.next; 3096 if (entry == &l3->slabs_free) 3097 goto must_grow; 3098 } 3099 3100 slabp = list_entry(entry, struct slab, list); 3101 check_slabp(cachep, slabp); 3102 check_spinlock_acquired(cachep); 3103 3104 /* 3105 * The slab was either on partial or free list so 3106 * there must be at least one object available for 3107 * allocation. 3108 */ 3109 BUG_ON(slabp->inuse >= cachep->num); 3110 3111 while (slabp->inuse < cachep->num && batchcount--) { 3112 STATS_INC_ALLOCED(cachep); 3113 STATS_INC_ACTIVE(cachep); 3114 STATS_SET_HIGH(cachep); 3115 3116 ac->entry[ac->avail++] = slab_get_obj(cachep, slabp, 3117 node); 3118 } 3119 check_slabp(cachep, slabp); 3120 3121 /* move slabp to correct slabp list: */ 3122 list_del(&slabp->list); 3123 if (slabp->free == BUFCTL_END) 3124 list_add(&slabp->list, &l3->slabs_full); 3125 else 3126 list_add(&slabp->list, &l3->slabs_partial); 3127 } 3128 3129must_grow: 3130 l3->free_objects -= ac->avail; 3131alloc_done: 3132 spin_unlock(&l3->list_lock); 3133 3134 if (unlikely(!ac->avail)) { 3135 int x; 3136 x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL); 3137 3138 /* cache_grow can reenable interrupts, then ac could change. */ 3139 ac = cpu_cache_get(cachep); 3140 if (!x && ac->avail == 0) /* no objects in sight? abort */ 3141 return NULL; 3142 3143 if (!ac->avail) /* objects refilled by interrupt? */ 3144 goto retry; 3145 } 3146 ac->touched = 1; 3147 return ac->entry[--ac->avail]; 3148} 3149 3150static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, 3151 gfp_t flags) 3152{ 3153 might_sleep_if(flags & __GFP_WAIT); 3154#if DEBUG 3155 kmem_flagcheck(cachep, flags); 3156#endif 3157} 3158 3159#if DEBUG 3160static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, 3161 gfp_t flags, void *objp, void *caller) 3162{ 3163 if (!objp) 3164 return objp; 3165 if (cachep->flags & SLAB_POISON) { 3166#ifdef CONFIG_DEBUG_PAGEALLOC 3167 if ((cachep->buffer_size % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) 3168 kernel_map_pages(virt_to_page(objp), 3169 cachep->buffer_size / PAGE_SIZE, 1); 3170 else 3171 check_poison_obj(cachep, objp); 3172#else 3173 check_poison_obj(cachep, objp); 3174#endif 3175 poison_obj(cachep, objp, POISON_INUSE); 3176 } 3177 if (cachep->flags & SLAB_STORE_USER) 3178 *dbg_userword(cachep, objp) = caller; 3179 3180 if (cachep->flags & SLAB_RED_ZONE) { 3181 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || 3182 *dbg_redzone2(cachep, objp) != RED_INACTIVE) { 3183 slab_error(cachep, "double free, or memory outside" 3184 " object was overwritten"); 3185 printk(KERN_ERR 3186 "%p: redzone 1:0x%llx, redzone 2:0x%llx\n", 3187 objp, *dbg_redzone1(cachep, objp), 3188 *dbg_redzone2(cachep, objp)); 3189 } 3190 *dbg_redzone1(cachep, objp) = RED_ACTIVE; 3191 *dbg_redzone2(cachep, objp) = RED_ACTIVE; 3192 } 3193#ifdef CONFIG_DEBUG_SLAB_LEAK 3194 { 3195 struct slab *slabp; 3196 unsigned objnr; 3197 3198 slabp = page_get_slab(virt_to_head_page(objp)); 3199 objnr = (unsigned)(objp - slabp->s_mem) / cachep->buffer_size; 3200 slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE; 3201 } 3202#endif 3203 objp += obj_offset(cachep); 3204 if (cachep->ctor && cachep->flags & SLAB_POISON) 3205 cachep->ctor(objp); 3206 if (ARCH_SLAB_MINALIGN && 3207 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) { 3208 printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n", 3209 objp, (int)ARCH_SLAB_MINALIGN); 3210 } 3211 return objp; 3212} 3213#else 3214#define cache_alloc_debugcheck_after(a,b,objp,d) (objp) 3215#endif 3216 3217static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags) 3218{ 3219 if (cachep == &cache_cache) 3220 return false; 3221 3222 return should_failslab(obj_size(cachep), flags, cachep->flags); 3223} 3224 3225static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3226{ 3227 void *objp; 3228 struct array_cache *ac; 3229 3230 check_irq_off(); 3231 3232 ac = cpu_cache_get(cachep); 3233 if (likely(ac->avail)) { 3234 STATS_INC_ALLOCHIT(cachep); 3235 ac->touched = 1; 3236 objp = ac->entry[--ac->avail]; 3237 } else { 3238 STATS_INC_ALLOCMISS(cachep); 3239 objp = cache_alloc_refill(cachep, flags); 3240 /* 3241 * the 'ac' may be updated by cache_alloc_refill(), 3242 * and kmemleak_erase() requires its correct value. 3243 */ 3244 ac = cpu_cache_get(cachep); 3245 } 3246 /* 3247 * To avoid a false negative, if an object that is in one of the 3248 * per-CPU caches is leaked, we need to make sure kmemleak doesn't 3249 * treat the array pointers as a reference to the object. 3250 */ 3251 if (objp) 3252 kmemleak_erase(&ac->entry[ac->avail]); 3253 return objp; 3254} 3255 3256#ifdef CONFIG_NUMA 3257/* 3258 * Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY. 3259 * 3260 * If we are in_interrupt, then process context, including cpusets and 3261 * mempolicy, may not apply and should not be used for allocation policy. 3262 */ 3263static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) 3264{ 3265 int nid_alloc, nid_here; 3266 3267 if (in_interrupt() || (flags & __GFP_THISNODE)) 3268 return NULL; 3269 nid_alloc = nid_here = numa_mem_id(); 3270 get_mems_allowed(); 3271 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) 3272 nid_alloc = cpuset_slab_spread_node(); 3273 else if (current->mempolicy) 3274 nid_alloc = slab_node(current->mempolicy); 3275 put_mems_allowed(); 3276 if (nid_alloc != nid_here) 3277 return ____cache_alloc_node(cachep, flags, nid_alloc); 3278 return NULL; 3279} 3280 3281/* 3282 * Fallback function if there was no memory available and no objects on a 3283 * certain node and fall back is permitted. First we scan all the 3284 * available nodelists for available objects. If that fails then we 3285 * perform an allocation without specifying a node. This allows the page 3286 * allocator to do its reclaim / fallback magic. We then insert the 3287 * slab into the proper nodelist and then allocate from it. 3288 */ 3289static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) 3290{ 3291 struct zonelist *zonelist; 3292 gfp_t local_flags; 3293 struct zoneref *z; 3294 struct zone *zone; 3295 enum zone_type high_zoneidx = gfp_zone(flags); 3296 void *obj = NULL; 3297 int nid; 3298 3299 if (flags & __GFP_THISNODE) 3300 return NULL; 3301 3302 get_mems_allowed(); 3303 zonelist = node_zonelist(slab_node(current->mempolicy), flags); 3304 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); 3305 3306retry: 3307 /* 3308 * Look through allowed nodes for objects available 3309 * from existing per node queues. 3310 */ 3311 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { 3312 nid = zone_to_nid(zone); 3313 3314 if (cpuset_zone_allowed_hardwall(zone, flags) && 3315 cache->nodelists[nid] && 3316 cache->nodelists[nid]->free_objects) { 3317 obj = ____cache_alloc_node(cache, 3318 flags | GFP_THISNODE, nid); 3319 if (obj) 3320 break; 3321 } 3322 } 3323 3324 if (!obj) { 3325 /* 3326 * This allocation will be performed within the constraints 3327 * of the current cpuset / memory policy requirements. 3328 * We may trigger various forms of reclaim on the allowed 3329 * set and go into memory reserves if necessary. 3330 */ 3331 if (local_flags & __GFP_WAIT) 3332 local_irq_enable(); 3333 kmem_flagcheck(cache, flags); 3334 obj = kmem_getpages(cache, local_flags, numa_mem_id()); 3335 if (local_flags & __GFP_WAIT) 3336 local_irq_disable(); 3337 if (obj) { 3338 /* 3339 * Insert into the appropriate per node queues 3340 */ 3341 nid = page_to_nid(virt_to_page(obj)); 3342 if (cache_grow(cache, flags, nid, obj)) { 3343 obj = ____cache_alloc_node(cache, 3344 flags | GFP_THISNODE, nid); 3345 if (!obj) 3346 /* 3347 * Another processor may allocate the 3348 * objects in the slab since we are 3349 * not holding any locks. 3350 */ 3351 goto retry; 3352 } else { 3353 /* cache_grow already freed obj */ 3354 obj = NULL; 3355 } 3356 } 3357 } 3358 put_mems_allowed(); 3359 return obj; 3360} 3361 3362/* 3363 * A interface to enable slab creation on nodeid 3364 */ 3365static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, 3366 int nodeid) 3367{ 3368 struct list_head *entry; 3369 struct slab *slabp; 3370 struct kmem_list3 *l3; 3371 void *obj; 3372 int x; 3373 3374 l3 = cachep->nodelists[nodeid]; 3375 BUG_ON(!l3); 3376 3377retry: 3378 check_irq_off(); 3379 spin_lock(&l3->list_lock); 3380 entry = l3->slabs_partial.next; 3381 if (entry == &l3->slabs_partial) { 3382 l3->free_touched = 1; 3383 entry = l3->slabs_free.next; 3384 if (entry == &l3->slabs_free) 3385 goto must_grow; 3386 } 3387 3388 slabp = list_entry(entry, struct slab, list); 3389 check_spinlock_acquired_node(cachep, nodeid); 3390 check_slabp(cachep, slabp); 3391 3392 STATS_INC_NODEALLOCS(cachep); 3393 STATS_INC_ACTIVE(cachep); 3394 STATS_SET_HIGH(cachep); 3395 3396 BUG_ON(slabp->inuse == cachep->num); 3397 3398 obj = slab_get_obj(cachep, slabp, nodeid); 3399 check_slabp(cachep, slabp); 3400 l3->free_objects--; 3401 /* move slabp to correct slabp list: */ 3402 list_del(&slabp->list); 3403 3404 if (slabp->free == BUFCTL_END) 3405 list_add(&slabp->list, &l3->slabs_full); 3406 else 3407 list_add(&slabp->list, &l3->slabs_partial); 3408 3409 spin_unlock(&l3->list_lock); 3410 goto done; 3411 3412must_grow: 3413 spin_unlock(&l3->list_lock); 3414 x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL); 3415 if (x) 3416 goto retry; 3417 3418 return fallback_alloc(cachep, flags); 3419 3420done: 3421 return obj; 3422} 3423 3424/** 3425 * kmem_cache_alloc_node - Allocate an object on the specified node 3426 * @cachep: The cache to allocate from. 3427 * @flags: See kmalloc(). 3428 * @nodeid: node number of the target node. 3429 * @caller: return address of caller, used for debug information 3430 * 3431 * Identical to kmem_cache_alloc but it will allocate memory on the given 3432 * node, which can improve the performance for cpu bound structures. 3433 * 3434 * Fallback to other node is possible if __GFP_THISNODE is not set. 3435 */ 3436static __always_inline void * 3437__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, 3438 void *caller) 3439{ 3440 unsigned long save_flags; 3441 void *ptr; 3442 int slab_node = numa_mem_id(); 3443 3444 flags &= gfp_allowed_mask; 3445 3446 lockdep_trace_alloc(flags); 3447 3448 if (slab_should_failslab(cachep, flags)) 3449 return NULL; 3450 3451 cache_alloc_debugcheck_before(cachep, flags); 3452 local_irq_save(save_flags); 3453 3454 if (nodeid == NUMA_NO_NODE) 3455 nodeid = slab_node; 3456 3457 if (unlikely(!cachep->nodelists[nodeid])) { 3458 /* Node not bootstrapped yet */ 3459 ptr = fallback_alloc(cachep, flags); 3460 goto out; 3461 } 3462 3463 if (nodeid == slab_node) { 3464 /* 3465 * Use the locally cached objects if possible. 3466 * However ____cache_alloc does not allow fallback 3467 * to other nodes. It may fail while we still have 3468 * objects on other nodes available. 3469 */ 3470 ptr = ____cache_alloc(cachep, flags); 3471 if (ptr) 3472 goto out; 3473 } 3474 /* ___cache_alloc_node can fall back to other nodes */ 3475 ptr = ____cache_alloc_node(cachep, flags, nodeid); 3476 out: 3477 local_irq_restore(save_flags); 3478 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller); 3479 kmemleak_alloc_recursive(ptr, obj_size(cachep), 1, cachep->flags, 3480 flags); 3481 3482 if (likely(ptr)) 3483 kmemcheck_slab_alloc(cachep, flags, ptr, obj_size(cachep)); 3484 3485 if (unlikely((flags & __GFP_ZERO) && ptr)) 3486 memset(ptr, 0, obj_size(cachep)); 3487 3488 return ptr; 3489} 3490 3491static __always_inline void * 3492__do_cache_alloc(struct kmem_cache *cache, gfp_t flags) 3493{ 3494 void *objp; 3495 3496 if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) { 3497 objp = alternate_node_alloc(cache, flags); 3498 if (objp) 3499 goto out; 3500 } 3501 objp = ____cache_alloc(cache, flags); 3502 3503 /* 3504 * We may just have run out of memory on the local node. 3505 * ____cache_alloc_node() knows how to locate memory on other nodes 3506 */ 3507 if (!objp) 3508 objp = ____cache_alloc_node(cache, flags, numa_mem_id()); 3509 3510 out: 3511 return objp; 3512} 3513#else 3514 3515static __always_inline void * 3516__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3517{ 3518 return ____cache_alloc(cachep, flags); 3519} 3520 3521#endif /* CONFIG_NUMA */ 3522 3523static __always_inline void * 3524__cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller) 3525{ 3526 unsigned long save_flags; 3527 void *objp; 3528 3529 flags &= gfp_allowed_mask; 3530 3531 lockdep_trace_alloc(flags); 3532 3533 if (slab_should_failslab(cachep, flags)) 3534 return NULL; 3535 3536 cache_alloc_debugcheck_before(cachep, flags); 3537 local_irq_save(save_flags); 3538 objp = __do_cache_alloc(cachep, flags); 3539 local_irq_restore(save_flags); 3540 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); 3541 kmemleak_alloc_recursive(objp, obj_size(cachep), 1, cachep->flags, 3542 flags); 3543 prefetchw(objp); 3544 3545 if (likely(objp)) 3546 kmemcheck_slab_alloc(cachep, flags, objp, obj_size(cachep)); 3547 3548 if (unlikely((flags & __GFP_ZERO) && objp)) 3549 memset(objp, 0, obj_size(cachep)); 3550 3551 return objp; 3552} 3553 3554/* 3555 * Caller needs to acquire correct kmem_list's list_lock 3556 */ 3557static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects, 3558 int node) 3559{ 3560 int i; 3561 struct kmem_list3 *l3; 3562 3563 for (i = 0; i < nr_objects; i++) { 3564 void *objp = objpp[i]; 3565 struct slab *slabp; 3566 3567 slabp = virt_to_slab(objp); 3568 l3 = cachep->nodelists[node]; 3569 list_del(&slabp->list); 3570 check_spinlock_acquired_node(cachep, node); 3571 check_slabp(cachep, slabp); 3572 slab_put_obj(cachep, slabp, objp, node); 3573 STATS_DEC_ACTIVE(cachep); 3574 l3->free_objects++; 3575 check_slabp(cachep, slabp); 3576 3577 /* fixup slab chains */ 3578 if (slabp->inuse == 0) { 3579 if (l3->free_objects > l3->free_limit) { 3580 l3->free_objects -= cachep->num; 3581 /* No need to drop any previously held 3582 * lock here, even if we have a off-slab slab 3583 * descriptor it is guaranteed to come from 3584 * a different cache, refer to comments before 3585 * alloc_slabmgmt. 3586 */ 3587 slab_destroy(cachep, slabp); 3588 } else { 3589 list_add(&slabp->list, &l3->slabs_free); 3590 } 3591 } else { 3592 /* Unconditionally move a slab to the end of the 3593 * partial list on free - maximum time for the 3594 * other objects to be freed, too. 3595 */ 3596 list_add_tail(&slabp->list, &l3->slabs_partial); 3597 } 3598 } 3599} 3600 3601static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) 3602{ 3603 int batchcount; 3604 struct kmem_list3 *l3; 3605 int node = numa_mem_id(); 3606 3607 batchcount = ac->batchcount; 3608#if DEBUG 3609 BUG_ON(!batchcount || batchcount > ac->avail); 3610#endif 3611 check_irq_off(); 3612 l3 = cachep->nodelists[node]; 3613 spin_lock(&l3->list_lock); 3614 if (l3->shared) { 3615 struct array_cache *shared_array = l3->shared; 3616 int max = shared_array->limit - shared_array->avail; 3617 if (max) { 3618 if (batchcount > max) 3619 batchcount = max; 3620 memcpy(&(shared_array->entry[shared_array->avail]), 3621 ac->entry, sizeof(void *) * batchcount); 3622 shared_array->avail += batchcount; 3623 goto free_done; 3624 } 3625 } 3626 3627 free_block(cachep, ac->entry, batchcount, node); 3628free_done: 3629#if STATS 3630 { 3631 int i = 0; 3632 struct list_head *p; 3633 3634 p = l3->slabs_free.next; 3635 while (p != &(l3->slabs_free)) { 3636 struct slab *slabp; 3637 3638 slabp = list_entry(p, struct slab, list); 3639 BUG_ON(slabp->inuse); 3640 3641 i++; 3642 p = p->next; 3643 } 3644 STATS_SET_FREEABLE(cachep, i); 3645 } 3646#endif 3647 spin_unlock(&l3->list_lock); 3648 ac->avail -= batchcount; 3649 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); 3650} 3651 3652/* 3653 * Release an obj back to its cache. If the obj has a constructed state, it must 3654 * be in this state _before_ it is released. Called with disabled ints. 3655 */ 3656static inline void __cache_free(struct kmem_cache *cachep, void *objp, 3657 void *caller) 3658{ 3659 struct array_cache *ac = cpu_cache_get(cachep); 3660 3661 check_irq_off(); 3662 kmemleak_free_recursive(objp, cachep->flags); 3663 objp = cache_free_debugcheck(cachep, objp, caller); 3664 3665 kmemcheck_slab_free(cachep, objp, obj_size(cachep)); 3666 3667 /* 3668 * Skip calling cache_free_alien() when the platform is not numa. 3669 * This will avoid cache misses that happen while accessing slabp (which 3670 * is per page memory reference) to get nodeid. Instead use a global 3671 * variable to skip the call, which is mostly likely to be present in 3672 * the cache. 3673 */ 3674 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) 3675 return; 3676 3677 if (likely(ac->avail < ac->limit)) { 3678 STATS_INC_FREEHIT(cachep); 3679 ac->entry[ac->avail++] = objp; 3680 return; 3681 } else { 3682 STATS_INC_FREEMISS(cachep); 3683 cache_flusharray(cachep, ac); 3684 ac->entry[ac->avail++] = objp; 3685 } 3686} 3687 3688/** 3689 * kmem_cache_alloc - Allocate an object 3690 * @cachep: The cache to allocate from. 3691 * @flags: See kmalloc(). 3692 * 3693 * Allocate an object from this cache. The flags are only relevant 3694 * if the cache has no available objects. 3695 */ 3696void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3697{ 3698 void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0)); 3699 3700 trace_kmem_cache_alloc(_RET_IP_, ret, 3701 obj_size(cachep), cachep->buffer_size, flags); 3702 3703 return ret; 3704} 3705EXPORT_SYMBOL(kmem_cache_alloc); 3706 3707#ifdef CONFIG_TRACING 3708void * 3709kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags) 3710{ 3711 void *ret; 3712 3713 ret = __cache_alloc(cachep, flags, __builtin_return_address(0)); 3714 3715 trace_kmalloc(_RET_IP_, ret, 3716 size, slab_buffer_size(cachep), flags); 3717 return ret; 3718} 3719EXPORT_SYMBOL(kmem_cache_alloc_trace); 3720#endif 3721 3722#ifdef CONFIG_NUMA 3723void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) 3724{ 3725 void *ret = __cache_alloc_node(cachep, flags, nodeid, 3726 __builtin_return_address(0)); 3727 3728 trace_kmem_cache_alloc_node(_RET_IP_, ret, 3729 obj_size(cachep), cachep->buffer_size, 3730 flags, nodeid); 3731 3732 return ret; 3733} 3734EXPORT_SYMBOL(kmem_cache_alloc_node); 3735 3736#ifdef CONFIG_TRACING 3737void *kmem_cache_alloc_node_trace(size_t size, 3738 struct kmem_cache *cachep, 3739 gfp_t flags, 3740 int nodeid) 3741{ 3742 void *ret; 3743 3744 ret = __cache_alloc_node(cachep, flags, nodeid, 3745 __builtin_return_address(0)); 3746 trace_kmalloc_node(_RET_IP_, ret, 3747 size, slab_buffer_size(cachep), 3748 flags, nodeid); 3749 return ret; 3750} 3751EXPORT_SYMBOL(kmem_cache_alloc_node_trace); 3752#endif 3753 3754static __always_inline void * 3755__do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller) 3756{ 3757 struct kmem_cache *cachep; 3758 3759 cachep = kmem_find_general_cachep(size, flags); 3760 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3761 return cachep; 3762 return kmem_cache_alloc_node_trace(size, cachep, flags, node); 3763} 3764 3765#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING) 3766void *__kmalloc_node(size_t size, gfp_t flags, int node) 3767{ 3768 return __do_kmalloc_node(size, flags, node, 3769 __builtin_return_address(0)); 3770} 3771EXPORT_SYMBOL(__kmalloc_node); 3772 3773void *__kmalloc_node_track_caller(size_t size, gfp_t flags, 3774 int node, unsigned long caller) 3775{ 3776 return __do_kmalloc_node(size, flags, node, (void *)caller); 3777} 3778EXPORT_SYMBOL(__kmalloc_node_track_caller); 3779#else 3780void *__kmalloc_node(size_t size, gfp_t flags, int node) 3781{ 3782 return __do_kmalloc_node(size, flags, node, NULL); 3783} 3784EXPORT_SYMBOL(__kmalloc_node); 3785#endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */ 3786#endif /* CONFIG_NUMA */ 3787 3788/** 3789 * __do_kmalloc - allocate memory 3790 * @size: how many bytes of memory are required. 3791 * @flags: the type of memory to allocate (see kmalloc). 3792 * @caller: function caller for debug tracking of the caller 3793 */ 3794static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, 3795 void *caller) 3796{ 3797 struct kmem_cache *cachep; 3798 void *ret; 3799 3800 /* If you want to save a few bytes .text space: replace 3801 * __ with kmem_. 3802 * Then kmalloc uses the uninlined functions instead of the inline 3803 * functions. 3804 */ 3805 cachep = __find_general_cachep(size, flags); 3806 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3807 return cachep; 3808 ret = __cache_alloc(cachep, flags, caller); 3809 3810 trace_kmalloc((unsigned long) caller, ret, 3811 size, cachep->buffer_size, flags); 3812 3813 return ret; 3814} 3815 3816 3817#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING) 3818void *__kmalloc(size_t size, gfp_t flags) 3819{ 3820 return __do_kmalloc(size, flags, __builtin_return_address(0)); 3821} 3822EXPORT_SYMBOL(__kmalloc); 3823 3824void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller) 3825{ 3826 return __do_kmalloc(size, flags, (void *)caller); 3827} 3828EXPORT_SYMBOL(__kmalloc_track_caller); 3829 3830#else 3831void *__kmalloc(size_t size, gfp_t flags) 3832{ 3833 return __do_kmalloc(size, flags, NULL); 3834} 3835EXPORT_SYMBOL(__kmalloc); 3836#endif 3837 3838/** 3839 * kmem_cache_free - Deallocate an object 3840 * @cachep: The cache the allocation was from. 3841 * @objp: The previously allocated object. 3842 * 3843 * Free an object which was previously allocated from this 3844 * cache. 3845 */ 3846void kmem_cache_free(struct kmem_cache *cachep, void *objp) 3847{ 3848 unsigned long flags; 3849 3850 local_irq_save(flags); 3851 debug_check_no_locks_freed(objp, obj_size(cachep)); 3852 if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) 3853 debug_check_no_obj_freed(objp, obj_size(cachep)); 3854 __cache_free(cachep, objp, __builtin_return_address(0)); 3855 local_irq_restore(flags); 3856 3857 trace_kmem_cache_free(_RET_IP_, objp); 3858} 3859EXPORT_SYMBOL(kmem_cache_free); 3860 3861/** 3862 * kfree - free previously allocated memory 3863 * @objp: pointer returned by kmalloc. 3864 * 3865 * If @objp is NULL, no operation is performed. 3866 * 3867 * Don't free memory not originally allocated by kmalloc() 3868 * or you will run into trouble. 3869 */ 3870void kfree(const void *objp) 3871{ 3872 struct kmem_cache *c; 3873 unsigned long flags; 3874 3875 trace_kfree(_RET_IP_, objp); 3876 3877 if (unlikely(ZERO_OR_NULL_PTR(objp))) 3878 return; 3879 local_irq_save(flags); 3880 kfree_debugcheck(objp); 3881 c = virt_to_cache(objp); 3882 debug_check_no_locks_freed(objp, obj_size(c)); 3883 debug_check_no_obj_freed(objp, obj_size(c)); 3884 __cache_free(c, (void *)objp, __builtin_return_address(0)); 3885 local_irq_restore(flags); 3886} 3887EXPORT_SYMBOL(kfree); 3888 3889unsigned int kmem_cache_size(struct kmem_cache *cachep) 3890{ 3891 return obj_size(cachep); 3892} 3893EXPORT_SYMBOL(kmem_cache_size); 3894 3895/* 3896 * This initializes kmem_list3 or resizes various caches for all nodes. 3897 */ 3898static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp) 3899{ 3900 int node; 3901 struct kmem_list3 *l3; 3902 struct array_cache *new_shared; 3903 struct array_cache **new_alien = NULL; 3904 3905 for_each_online_node(node) { 3906 3907 if (use_alien_caches) { 3908 new_alien = alloc_alien_cache(node, cachep->limit, gfp); 3909 if (!new_alien) 3910 goto fail; 3911 } 3912 3913 new_shared = NULL; 3914 if (cachep->shared) { 3915 new_shared = alloc_arraycache(node, 3916 cachep->shared*cachep->batchcount, 3917 0xbaadf00d, gfp); 3918 if (!new_shared) { 3919 free_alien_cache(new_alien); 3920 goto fail; 3921 } 3922 } 3923 3924 l3 = cachep->nodelists[node]; 3925 if (l3) { 3926 struct array_cache *shared = l3->shared; 3927 3928 spin_lock_irq(&l3->list_lock); 3929 3930 if (shared) 3931 free_block(cachep, shared->entry, 3932 shared->avail, node); 3933 3934 l3->shared = new_shared; 3935 if (!l3->alien) { 3936 l3->alien = new_alien; 3937 new_alien = NULL; 3938 } 3939 l3->free_limit = (1 + nr_cpus_node(node)) * 3940 cachep->batchcount + cachep->num; 3941 spin_unlock_irq(&l3->list_lock); 3942 kfree(shared); 3943 free_alien_cache(new_alien); 3944 continue; 3945 } 3946 l3 = kmalloc_node(sizeof(struct kmem_list3), gfp, node); 3947 if (!l3) { 3948 free_alien_cache(new_alien); 3949 kfree(new_shared); 3950 goto fail; 3951 } 3952 3953 kmem_list3_init(l3); 3954 l3->next_reap = jiffies + REAPTIMEOUT_LIST3 + 3955 ((unsigned long)cachep) % REAPTIMEOUT_LIST3; 3956 l3->shared = new_shared; 3957 l3->alien = new_alien; 3958 l3->free_limit = (1 + nr_cpus_node(node)) * 3959 cachep->batchcount + cachep->num; 3960 cachep->nodelists[node] = l3; 3961 } 3962 return 0; 3963 3964fail: 3965 if (!cachep->next.next) { 3966 /* Cache is not active yet. Roll back what we did */ 3967 node--; 3968 while (node >= 0) { 3969 if (cachep->nodelists[node]) { 3970 l3 = cachep->nodelists[node]; 3971 3972 kfree(l3->shared); 3973 free_alien_cache(l3->alien); 3974 kfree(l3); 3975 cachep->nodelists[node] = NULL; 3976 } 3977 node--; 3978 } 3979 } 3980 return -ENOMEM; 3981} 3982 3983struct ccupdate_struct { 3984 struct kmem_cache *cachep; 3985 struct array_cache *new[0]; 3986}; 3987 3988static void do_ccupdate_local(void *info) 3989{ 3990 struct ccupdate_struct *new = info; 3991 struct array_cache *old; 3992 3993 check_irq_off(); 3994 old = cpu_cache_get(new->cachep); 3995 3996 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()]; 3997 new->new[smp_processor_id()] = old; 3998} 3999 4000/* Always called with the cache_chain_mutex held */ 4001static int do_tune_cpucache(struct kmem_cache *cachep, int limit, 4002 int batchcount, int shared, gfp_t gfp) 4003{ 4004 struct ccupdate_struct *new; 4005 int i; 4006 4007 new = kzalloc(sizeof(*new) + nr_cpu_ids * sizeof(struct array_cache *), 4008 gfp); 4009 if (!new) 4010 return -ENOMEM; 4011 4012 for_each_online_cpu(i) { 4013 new->new[i] = alloc_arraycache(cpu_to_mem(i), limit, 4014 batchcount, gfp); 4015 if (!new->new[i]) { 4016 for (i--; i >= 0; i--) 4017 kfree(new->new[i]); 4018 kfree(new); 4019 return -ENOMEM; 4020 } 4021 } 4022 new->cachep = cachep; 4023 4024 on_each_cpu(do_ccupdate_local, (void *)new, 1); 4025 4026 check_irq_on(); 4027 cachep->batchcount = batchcount; 4028 cachep->limit = limit; 4029 cachep->shared = shared; 4030 4031 for_each_online_cpu(i) { 4032 struct array_cache *ccold = new->new[i]; 4033 if (!ccold) 4034 continue; 4035 spin_lock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock); 4036 free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i)); 4037 spin_unlock_irq(&cachep->nodelists[cpu_to_mem(i)]->list_lock); 4038 kfree(ccold); 4039 } 4040 kfree(new); 4041 return alloc_kmemlist(cachep, gfp); 4042} 4043 4044/* Called with cache_chain_mutex held always */ 4045static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) 4046{ 4047 int err; 4048 int limit, shared; 4049 4050 /* 4051 * The head array serves three purposes: 4052 * - create a LIFO ordering, i.e. return objects that are cache-warm 4053 * - reduce the number of spinlock operations. 4054 * - reduce the number of linked list operations on the slab and 4055 * bufctl chains: array operations are cheaper. 4056 * The numbers are guessed, we should auto-tune as described by 4057 * Bonwick. 4058 */ 4059 if (cachep->buffer_size > 131072) 4060 limit = 1; 4061 else if (cachep->buffer_size > PAGE_SIZE) 4062 limit = 8; 4063 else if (cachep->buffer_size > 1024) 4064 limit = 24; 4065 else if (cachep->buffer_size > 256) 4066 limit = 54; 4067 else 4068 limit = 120; 4069 4070 /* 4071 * CPU bound tasks (e.g. network routing) can exhibit cpu bound 4072 * allocation behaviour: Most allocs on one cpu, most free operations 4073 * on another cpu. For these cases, an efficient object passing between 4074 * cpus is necessary. This is provided by a shared array. The array 4075 * replaces Bonwick's magazine layer. 4076 * On uniprocessor, it's functionally equivalent (but less efficient) 4077 * to a larger limit. Thus disabled by default. 4078 */ 4079 shared = 0; 4080 if (cachep->buffer_size <= PAGE_SIZE && num_possible_cpus() > 1) 4081 shared = 8; 4082 4083#if DEBUG 4084 /* 4085 * With debugging enabled, large batchcount lead to excessively long 4086 * periods with disabled local interrupts. Limit the batchcount 4087 */ 4088 if (limit > 32) 4089 limit = 32; 4090#endif 4091 err = do_tune_cpucache(cachep, limit, (limit + 1) / 2, shared, gfp); 4092 if (err) 4093 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n", 4094 cachep->name, -err); 4095 return err; 4096} 4097 4098/* 4099 * Drain an array if it contains any elements taking the l3 lock only if 4100 * necessary. Note that the l3 listlock also protects the array_cache 4101 * if drain_array() is used on the shared array. 4102 */ 4103static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3, 4104 struct array_cache *ac, int force, int node) 4105{ 4106 int tofree; 4107 4108 if (!ac || !ac->avail) 4109 return; 4110 if (ac->touched && !force) { 4111 ac->touched = 0; 4112 } else { 4113 spin_lock_irq(&l3->list_lock); 4114 if (ac->avail) { 4115 tofree = force ? ac->avail : (ac->limit + 4) / 5; 4116 if (tofree > ac->avail) 4117 tofree = (ac->avail + 1) / 2; 4118 free_block(cachep, ac->entry, tofree, node); 4119 ac->avail -= tofree; 4120 memmove(ac->entry, &(ac->entry[tofree]), 4121 sizeof(void *) * ac->avail); 4122 } 4123 spin_unlock_irq(&l3->list_lock); 4124 } 4125} 4126 4127/** 4128 * cache_reap - Reclaim memory from caches. 4129 * @w: work descriptor 4130 * 4131 * Called from workqueue/eventd every few seconds. 4132 * Purpose: 4133 * - clear the per-cpu caches for this CPU. 4134 * - return freeable pages to the main free memory pool. 4135 * 4136 * If we cannot acquire the cache chain mutex then just give up - we'll try 4137 * again on the next iteration. 4138 */ 4139static void cache_reap(struct work_struct *w) 4140{ 4141 struct kmem_cache *searchp; 4142 struct kmem_list3 *l3; 4143 int node = numa_mem_id(); 4144 struct delayed_work *work = to_delayed_work(w); 4145 4146 if (!mutex_trylock(&cache_chain_mutex)) 4147 /* Give up. Setup the next iteration. */ 4148 goto out; 4149 4150 list_for_each_entry(searchp, &cache_chain, next) { 4151 check_irq_on(); 4152 4153 /* 4154 * We only take the l3 lock if absolutely necessary and we 4155 * have established with reasonable certainty that 4156 * we can do some work if the lock was obtained. 4157 */ 4158 l3 = searchp->nodelists[node]; 4159 4160 reap_alien(searchp, l3); 4161 4162 drain_array(searchp, l3, cpu_cache_get(searchp), 0, node); 4163 4164 /* 4165 * These are racy checks but it does not matter 4166 * if we skip one check or scan twice. 4167 */ 4168 if (time_after(l3->next_reap, jiffies)) 4169 goto next; 4170 4171 l3->next_reap = jiffies + REAPTIMEOUT_LIST3; 4172 4173 drain_array(searchp, l3, l3->shared, 0, node); 4174 4175 if (l3->free_touched) 4176 l3->free_touched = 0; 4177 else { 4178 int freed; 4179 4180 freed = drain_freelist(searchp, l3, (l3->free_limit + 4181 5 * searchp->num - 1) / (5 * searchp->num)); 4182 STATS_ADD_REAPED(searchp, freed); 4183 } 4184next: 4185 cond_resched(); 4186 } 4187 check_irq_on(); 4188 mutex_unlock(&cache_chain_mutex); 4189 next_reap_node(); 4190out: 4191 /* Set up the next iteration */ 4192 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_CPUC)); 4193} 4194 4195#ifdef CONFIG_SLABINFO 4196 4197static void print_slabinfo_header(struct seq_file *m) 4198{ 4199 /* 4200 * Output format version, so at least we can change it 4201 * without _too_ many complaints. 4202 */ 4203#if STATS 4204 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 4205#else 4206 seq_puts(m, "slabinfo - version: 2.1\n"); 4207#endif 4208 seq_puts(m, "# name <active_objs> <num_objs> <objsize> " 4209 "<objperslab> <pagesperslab>"); 4210 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 4211 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 4212#if STATS 4213 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> " 4214 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 4215 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 4216#endif 4217 seq_putc(m, '\n'); 4218} 4219 4220static void *s_start(struct seq_file *m, loff_t *pos) 4221{ 4222 loff_t n = *pos; 4223 4224 mutex_lock(&cache_chain_mutex); 4225 if (!n) 4226 print_slabinfo_header(m); 4227 4228 return seq_list_start(&cache_chain, *pos); 4229} 4230 4231static void *s_next(struct seq_file *m, void *p, loff_t *pos) 4232{ 4233 return seq_list_next(p, &cache_chain, pos); 4234} 4235 4236static void s_stop(struct seq_file *m, void *p) 4237{ 4238 mutex_unlock(&cache_chain_mutex); 4239} 4240 4241static int s_show(struct seq_file *m, void *p) 4242{ 4243 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next); 4244 struct slab *slabp; 4245 unsigned long active_objs; 4246 unsigned long num_objs; 4247 unsigned long active_slabs = 0; 4248 unsigned long num_slabs, free_objects = 0, shared_avail = 0; 4249 const char *name; 4250 char *error = NULL; 4251 int node; 4252 struct kmem_list3 *l3; 4253 4254 active_objs = 0; 4255 num_slabs = 0; 4256 for_each_online_node(node) { 4257 l3 = cachep->nodelists[node]; 4258 if (!l3) 4259 continue; 4260 4261 check_irq_on(); 4262 spin_lock_irq(&l3->list_lock); 4263 4264 list_for_each_entry(slabp, &l3->slabs_full, list) { 4265 if (slabp->inuse != cachep->num && !error) 4266 error = "slabs_full accounting error"; 4267 active_objs += cachep->num; 4268 active_slabs++; 4269 } 4270 list_for_each_entry(slabp, &l3->slabs_partial, list) { 4271 if (slabp->inuse == cachep->num && !error) 4272 error = "slabs_partial inuse accounting error"; 4273 if (!slabp->inuse && !error) 4274 error = "slabs_partial/inuse accounting error"; 4275 active_objs += slabp->inuse; 4276 active_slabs++; 4277 } 4278 list_for_each_entry(slabp, &l3->slabs_free, list) { 4279 if (slabp->inuse && !error) 4280 error = "slabs_free/inuse accounting error"; 4281 num_slabs++; 4282 } 4283 free_objects += l3->free_objects; 4284 if (l3->shared) 4285 shared_avail += l3->shared->avail; 4286 4287 spin_unlock_irq(&l3->list_lock); 4288 } 4289 num_slabs += active_slabs; 4290 num_objs = num_slabs * cachep->num; 4291 if (num_objs - active_objs != free_objects && !error) 4292 error = "free_objects accounting error"; 4293 4294 name = cachep->name; 4295 if (error) 4296 printk(KERN_ERR "slab: cache %s error: %s\n", name, error); 4297 4298 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 4299 name, active_objs, num_objs, cachep->buffer_size, 4300 cachep->num, (1 << cachep->gfporder)); 4301 seq_printf(m, " : tunables %4u %4u %4u", 4302 cachep->limit, cachep->batchcount, cachep->shared); 4303 seq_printf(m, " : slabdata %6lu %6lu %6lu", 4304 active_slabs, num_slabs, shared_avail); 4305#if STATS 4306 { /* list3 stats */ 4307 unsigned long high = cachep->high_mark; 4308 unsigned long allocs = cachep->num_allocations; 4309 unsigned long grown = cachep->grown; 4310 unsigned long reaped = cachep->reaped; 4311 unsigned long errors = cachep->errors; 4312 unsigned long max_freeable = cachep->max_freeable; 4313 unsigned long node_allocs = cachep->node_allocs; 4314 unsigned long node_frees = cachep->node_frees; 4315 unsigned long overflows = cachep->node_overflow; 4316 4317 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu " 4318 "%4lu %4lu %4lu %4lu %4lu", 4319 allocs, high, grown, 4320 reaped, errors, max_freeable, node_allocs, 4321 node_frees, overflows); 4322 } 4323 /* cpu stats */ 4324 { 4325 unsigned long allochit = atomic_read(&cachep->allochit); 4326 unsigned long allocmiss = atomic_read(&cachep->allocmiss); 4327 unsigned long freehit = atomic_read(&cachep->freehit); 4328 unsigned long freemiss = atomic_read(&cachep->freemiss); 4329 4330 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", 4331 allochit, allocmiss, freehit, freemiss); 4332 } 4333#endif 4334 seq_putc(m, '\n'); 4335 return 0; 4336} 4337 4338/* 4339 * slabinfo_op - iterator that generates /proc/slabinfo 4340 * 4341 * Output layout: 4342 * cache-name 4343 * num-active-objs 4344 * total-objs 4345 * object size 4346 * num-active-slabs 4347 * total-slabs 4348 * num-pages-per-slab 4349 * + further values on SMP and with statistics enabled 4350 */ 4351 4352static const struct seq_operations slabinfo_op = { 4353 .start = s_start, 4354 .next = s_next, 4355 .stop = s_stop, 4356 .show = s_show, 4357}; 4358 4359#define MAX_SLABINFO_WRITE 128 4360/** 4361 * slabinfo_write - Tuning for the slab allocator 4362 * @file: unused 4363 * @buffer: user buffer 4364 * @count: data length 4365 * @ppos: unused 4366 */ 4367static ssize_t slabinfo_write(struct file *file, const char __user *buffer, 4368 size_t count, loff_t *ppos) 4369{ 4370 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; 4371 int limit, batchcount, shared, res; 4372 struct kmem_cache *cachep; 4373 4374 if (count > MAX_SLABINFO_WRITE) 4375 return -EINVAL; 4376 if (copy_from_user(&kbuf, buffer, count)) 4377 return -EFAULT; 4378 kbuf[MAX_SLABINFO_WRITE] = '\0'; 4379 4380 tmp = strchr(kbuf, ' '); 4381 if (!tmp) 4382 return -EINVAL; 4383 *tmp = '\0'; 4384 tmp++; 4385 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) 4386 return -EINVAL; 4387 4388 /* Find the cache in the chain of caches. */ 4389 mutex_lock(&cache_chain_mutex); 4390 res = -EINVAL; 4391 list_for_each_entry(cachep, &cache_chain, next) { 4392 if (!strcmp(cachep->name, kbuf)) { 4393 if (limit < 1 || batchcount < 1 || 4394 batchcount > limit || shared < 0) { 4395 res = 0; 4396 } else { 4397 res = do_tune_cpucache(cachep, limit, 4398 batchcount, shared, 4399 GFP_KERNEL); 4400 } 4401 break; 4402 } 4403 } 4404 mutex_unlock(&cache_chain_mutex); 4405 if (res >= 0) 4406 res = count; 4407 return res; 4408} 4409 4410static int slabinfo_open(struct inode *inode, struct file *file) 4411{ 4412 return seq_open(file, &slabinfo_op); 4413} 4414 4415static const struct file_operations proc_slabinfo_operations = { 4416 .open = slabinfo_open, 4417 .read = seq_read, 4418 .write = slabinfo_write, 4419 .llseek = seq_lseek, 4420 .release = seq_release, 4421}; 4422 4423#ifdef CONFIG_DEBUG_SLAB_LEAK 4424 4425static void *leaks_start(struct seq_file *m, loff_t *pos) 4426{ 4427 mutex_lock(&cache_chain_mutex); 4428 return seq_list_start(&cache_chain, *pos); 4429} 4430 4431static inline int add_caller(unsigned long *n, unsigned long v) 4432{ 4433 unsigned long *p; 4434 int l; 4435 if (!v) 4436 return 1; 4437 l = n[1]; 4438 p = n + 2; 4439 while (l) { 4440 int i = l/2; 4441 unsigned long *q = p + 2 * i; 4442 if (*q == v) { 4443 q[1]++; 4444 return 1; 4445 } 4446 if (*q > v) { 4447 l = i; 4448 } else { 4449 p = q + 2; 4450 l -= i + 1; 4451 } 4452 } 4453 if (++n[1] == n[0]) 4454 return 0; 4455 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n)); 4456 p[0] = v; 4457 p[1] = 1; 4458 return 1; 4459} 4460 4461static void handle_slab(unsigned long *n, struct kmem_cache *c, struct slab *s) 4462{ 4463 void *p; 4464 int i; 4465 if (n[0] == n[1]) 4466 return; 4467 for (i = 0, p = s->s_mem; i < c->num; i++, p += c->buffer_size) { 4468 if (slab_bufctl(s)[i] != BUFCTL_ACTIVE) 4469 continue; 4470 if (!add_caller(n, (unsigned long)*dbg_userword(c, p))) 4471 return; 4472 } 4473} 4474 4475static void show_symbol(struct seq_file *m, unsigned long address) 4476{ 4477#ifdef CONFIG_KALLSYMS 4478 unsigned long offset, size; 4479 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN]; 4480 4481 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) { 4482 seq_printf(m, "%s+%#lx/%#lx", name, offset, size); 4483 if (modname[0]) 4484 seq_printf(m, " [%s]", modname); 4485 return; 4486 } 4487#endif 4488 seq_printf(m, "%p", (void *)address); 4489} 4490 4491static int leaks_show(struct seq_file *m, void *p) 4492{ 4493 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, next); 4494 struct slab *slabp; 4495 struct kmem_list3 *l3; 4496 const char *name; 4497 unsigned long *n = m->private; 4498 int node; 4499 int i; 4500 4501 if (!(cachep->flags & SLAB_STORE_USER)) 4502 return 0; 4503 if (!(cachep->flags & SLAB_RED_ZONE)) 4504 return 0; 4505 4506 /* OK, we can do it */ 4507 4508 n[1] = 0; 4509 4510 for_each_online_node(node) { 4511 l3 = cachep->nodelists[node]; 4512 if (!l3) 4513 continue; 4514 4515 check_irq_on(); 4516 spin_lock_irq(&l3->list_lock); 4517 4518 list_for_each_entry(slabp, &l3->slabs_full, list) 4519 handle_slab(n, cachep, slabp); 4520 list_for_each_entry(slabp, &l3->slabs_partial, list) 4521 handle_slab(n, cachep, slabp); 4522 spin_unlock_irq(&l3->list_lock); 4523 } 4524 name = cachep->name; 4525 if (n[0] == n[1]) { 4526 /* Increase the buffer size */ 4527 mutex_unlock(&cache_chain_mutex); 4528 m->private = kzalloc(n[0] * 4 * sizeof(unsigned long), GFP_KERNEL); 4529 if (!m->private) { 4530 /* Too bad, we are really out */ 4531 m->private = n; 4532 mutex_lock(&cache_chain_mutex); 4533 return -ENOMEM; 4534 } 4535 *(unsigned long *)m->private = n[0] * 2; 4536 kfree(n); 4537 mutex_lock(&cache_chain_mutex); 4538 /* Now make sure this entry will be retried */ 4539 m->count = m->size; 4540 return 0; 4541 } 4542 for (i = 0; i < n[1]; i++) { 4543 seq_printf(m, "%s: %lu ", name, n[2*i+3]); 4544 show_symbol(m, n[2*i+2]); 4545 seq_putc(m, '\n'); 4546 } 4547 4548 return 0; 4549} 4550 4551static const struct seq_operations slabstats_op = { 4552 .start = leaks_start, 4553 .next = s_next, 4554 .stop = s_stop, 4555 .show = leaks_show, 4556}; 4557 4558static int slabstats_open(struct inode *inode, struct file *file) 4559{ 4560 unsigned long *n = kzalloc(PAGE_SIZE, GFP_KERNEL); 4561 int ret = -ENOMEM; 4562 if (n) { 4563 ret = seq_open(file, &slabstats_op); 4564 if (!ret) { 4565 struct seq_file *m = file->private_data; 4566 *n = PAGE_SIZE / (2 * sizeof(unsigned long)); 4567 m->private = n; 4568 n = NULL; 4569 } 4570 kfree(n); 4571 } 4572 return ret; 4573} 4574 4575static const struct file_operations proc_slabstats_operations = { 4576 .open = slabstats_open, 4577 .read = seq_read, 4578 .llseek = seq_lseek, 4579 .release = seq_release_private, 4580}; 4581#endif 4582 4583static int __init slab_proc_init(void) 4584{ 4585 proc_create("slabinfo",S_IWUSR|S_IRUSR,NULL,&proc_slabinfo_operations); 4586#ifdef CONFIG_DEBUG_SLAB_LEAK 4587 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations); 4588#endif 4589 return 0; 4590} 4591module_init(slab_proc_init); 4592#endif 4593 4594/** 4595 * ksize - get the actual amount of memory allocated for a given object 4596 * @objp: Pointer to the object 4597 * 4598 * kmalloc may internally round up allocations and return more memory 4599 * than requested. ksize() can be used to determine the actual amount of 4600 * memory allocated. The caller may use this additional memory, even though 4601 * a smaller amount of memory was initially specified with the kmalloc call. 4602 * The caller must guarantee that objp points to a valid object previously 4603 * allocated with either kmalloc() or kmem_cache_alloc(). The object 4604 * must not be freed during the duration of the call. 4605 */ 4606size_t ksize(const void *objp) 4607{ 4608 BUG_ON(!objp); 4609 if (unlikely(objp == ZERO_SIZE_PTR)) 4610 return 0; 4611 4612 return obj_size(virt_to_cache(objp)); 4613} 4614EXPORT_SYMBOL(ksize); 4615