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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /mm/slab.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
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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 intializations 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 kmem_cache_t 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 semaphore 'cache_chain_sem'.
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 */
79
80#include <linux/config.h>
81#include <linux/slab.h>
82#include <linux/mm.h>
83#include <linux/swap.h>
84#include <linux/cache.h>
85#include <linux/interrupt.h>
86#include <linux/init.h>
87#include <linux/compiler.h>
88#include <linux/seq_file.h>
89#include <linux/notifier.h>
90#include <linux/kallsyms.h>
91#include <linux/cpu.h>
92#include <linux/sysctl.h>
93#include <linux/module.h>
94#include <linux/rcupdate.h>
95
96#include <asm/uaccess.h>
97#include <asm/cacheflush.h>
98#include <asm/tlbflush.h>
99#include <asm/page.h>
100
101/*
102 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
103 * SLAB_RED_ZONE & SLAB_POISON.
104 * 0 for faster, smaller code (especially in the critical paths).
105 *
106 * STATS - 1 to collect stats for /proc/slabinfo.
107 * 0 for faster, smaller code (especially in the critical paths).
108 *
109 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
110 */
111
112#ifdef CONFIG_DEBUG_SLAB
113#define DEBUG 1
114#define STATS 1
115#define FORCED_DEBUG 1
116#else
117#define DEBUG 0
118#define STATS 0
119#define FORCED_DEBUG 0
120#endif
121
122
123/* Shouldn't this be in a header file somewhere? */
124#define BYTES_PER_WORD sizeof(void *)
125
126#ifndef cache_line_size
127#define cache_line_size() L1_CACHE_BYTES
128#endif
129
130#ifndef ARCH_KMALLOC_MINALIGN
131/*
132 * Enforce a minimum alignment for the kmalloc caches.
133 * Usually, the kmalloc caches are cache_line_size() aligned, except when
134 * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
135 * Some archs want to perform DMA into kmalloc caches and need a guaranteed
136 * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
137 * Note that this flag disables some debug features.
138 */
139#define ARCH_KMALLOC_MINALIGN 0
140#endif
141
142#ifndef ARCH_SLAB_MINALIGN
143/*
144 * Enforce a minimum alignment for all caches.
145 * Intended for archs that get misalignment faults even for BYTES_PER_WORD
146 * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
147 * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
148 * some debug features.
149 */
150#define ARCH_SLAB_MINALIGN 0
151#endif
152
153#ifndef ARCH_KMALLOC_FLAGS
154#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
155#endif
156
157/* Legal flag mask for kmem_cache_create(). */
158#if DEBUG
159# define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
160 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
161 SLAB_NO_REAP | SLAB_CACHE_DMA | \
162 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
163 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
164 SLAB_DESTROY_BY_RCU)
165#else
166# define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \
167 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
168 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
169 SLAB_DESTROY_BY_RCU)
170#endif
171
172/*
173 * kmem_bufctl_t:
174 *
175 * Bufctl's are used for linking objs within a slab
176 * linked offsets.
177 *
178 * This implementation relies on "struct page" for locating the cache &
179 * slab an object belongs to.
180 * This allows the bufctl structure to be small (one int), but limits
181 * the number of objects a slab (not a cache) can contain when off-slab
182 * bufctls are used. The limit is the size of the largest general cache
183 * that does not use off-slab slabs.
184 * For 32bit archs with 4 kB pages, is this 56.
185 * This is not serious, as it is only for large objects, when it is unwise
186 * to have too many per slab.
187 * Note: This limit can be raised by introducing a general cache whose size
188 * is less than 512 (PAGE_SIZE<<3), but greater than 256.
189 */
190
191#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
192#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
193#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2)
194
195/* Max number of objs-per-slab for caches which use off-slab slabs.
196 * Needed to avoid a possible looping condition in cache_grow().
197 */
198static unsigned long offslab_limit;
199
200/*
201 * struct slab
202 *
203 * Manages the objs in a slab. Placed either at the beginning of mem allocated
204 * for a slab, or allocated from an general cache.
205 * Slabs are chained into three list: fully used, partial, fully free slabs.
206 */
207struct slab {
208 struct list_head list;
209 unsigned long colouroff;
210 void *s_mem; /* including colour offset */
211 unsigned int inuse; /* num of objs active in slab */
212 kmem_bufctl_t free;
213};
214
215/*
216 * struct slab_rcu
217 *
218 * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
219 * arrange for kmem_freepages to be called via RCU. This is useful if
220 * we need to approach a kernel structure obliquely, from its address
221 * obtained without the usual locking. We can lock the structure to
222 * stabilize it and check it's still at the given address, only if we
223 * can be sure that the memory has not been meanwhile reused for some
224 * other kind of object (which our subsystem's lock might corrupt).
225 *
226 * rcu_read_lock before reading the address, then rcu_read_unlock after
227 * taking the spinlock within the structure expected at that address.
228 *
229 * We assume struct slab_rcu can overlay struct slab when destroying.
230 */
231struct slab_rcu {
232 struct rcu_head head;
233 kmem_cache_t *cachep;
234 void *addr;
235};
236
237/*
238 * struct array_cache
239 *
240 * Per cpu structures
241 * Purpose:
242 * - LIFO ordering, to hand out cache-warm objects from _alloc
243 * - reduce the number of linked list operations
244 * - reduce spinlock operations
245 *
246 * The limit is stored in the per-cpu structure to reduce the data cache
247 * footprint.
248 *
249 */
250struct array_cache {
251 unsigned int avail;
252 unsigned int limit;
253 unsigned int batchcount;
254 unsigned int touched;
255};
256
257/* bootstrap: The caches do not work without cpuarrays anymore,
258 * but the cpuarrays are allocated from the generic caches...
259 */
260#define BOOT_CPUCACHE_ENTRIES 1
261struct arraycache_init {
262 struct array_cache cache;
263 void * entries[BOOT_CPUCACHE_ENTRIES];
264};
265
266/*
267 * The slab lists of all objects.
268 * Hopefully reduce the internal fragmentation
269 * NUMA: The spinlock could be moved from the kmem_cache_t
270 * into this structure, too. Figure out what causes
271 * fewer cross-node spinlock operations.
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 int free_touched;
279 unsigned long next_reap;
280 struct array_cache *shared;
281};
282
283#define LIST3_INIT(parent) \
284 { \
285 .slabs_full = LIST_HEAD_INIT(parent.slabs_full), \
286 .slabs_partial = LIST_HEAD_INIT(parent.slabs_partial), \
287 .slabs_free = LIST_HEAD_INIT(parent.slabs_free) \
288 }
289#define list3_data(cachep) \
290 (&(cachep)->lists)
291
292/* NUMA: per-node */
293#define list3_data_ptr(cachep, ptr) \
294 list3_data(cachep)
295
296/*
297 * kmem_cache_t
298 *
299 * manages a cache.
300 */
301
302struct kmem_cache_s {
303/* 1) per-cpu data, touched during every alloc/free */
304 struct array_cache *array[NR_CPUS];
305 unsigned int batchcount;
306 unsigned int limit;
307/* 2) touched by every alloc & free from the backend */
308 struct kmem_list3 lists;
309 /* NUMA: kmem_3list_t *nodelists[MAX_NUMNODES] */
310 unsigned int objsize;
311 unsigned int flags; /* constant flags */
312 unsigned int num; /* # of objs per slab */
313 unsigned int free_limit; /* upper limit of objects in the lists */
314 spinlock_t spinlock;
315
316/* 3) cache_grow/shrink */
317 /* order of pgs per slab (2^n) */
318 unsigned int gfporder;
319
320 /* force GFP flags, e.g. GFP_DMA */
321 unsigned int gfpflags;
322
323 size_t colour; /* cache colouring range */
324 unsigned int colour_off; /* colour offset */
325 unsigned int colour_next; /* cache colouring */
326 kmem_cache_t *slabp_cache;
327 unsigned int slab_size;
328 unsigned int dflags; /* dynamic flags */
329
330 /* constructor func */
331 void (*ctor)(void *, kmem_cache_t *, unsigned long);
332
333 /* de-constructor func */
334 void (*dtor)(void *, kmem_cache_t *, unsigned long);
335
336/* 4) cache creation/removal */
337 const char *name;
338 struct list_head next;
339
340/* 5) statistics */
341#if STATS
342 unsigned long num_active;
343 unsigned long num_allocations;
344 unsigned long high_mark;
345 unsigned long grown;
346 unsigned long reaped;
347 unsigned long errors;
348 unsigned long max_freeable;
349 unsigned long node_allocs;
350 atomic_t allochit;
351 atomic_t allocmiss;
352 atomic_t freehit;
353 atomic_t freemiss;
354#endif
355#if DEBUG
356 int dbghead;
357 int reallen;
358#endif
359};
360
361#define CFLGS_OFF_SLAB (0x80000000UL)
362#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
363
364#define BATCHREFILL_LIMIT 16
365/* Optimization question: fewer reaps means less
366 * probability for unnessary cpucache drain/refill cycles.
367 *
368 * OTHO the cpuarrays can contain lots of objects,
369 * which could lock up otherwise freeable slabs.
370 */
371#define REAPTIMEOUT_CPUC (2*HZ)
372#define REAPTIMEOUT_LIST3 (4*HZ)
373
374#if STATS
375#define STATS_INC_ACTIVE(x) ((x)->num_active++)
376#define STATS_DEC_ACTIVE(x) ((x)->num_active--)
377#define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
378#define STATS_INC_GROWN(x) ((x)->grown++)
379#define STATS_INC_REAPED(x) ((x)->reaped++)
380#define STATS_SET_HIGH(x) do { 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_SET_FREEABLE(x, i) \
386 do { if ((x)->max_freeable < i) \
387 (x)->max_freeable = i; \
388 } while (0)
389
390#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
391#define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
392#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
393#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
394#else
395#define STATS_INC_ACTIVE(x) do { } while (0)
396#define STATS_DEC_ACTIVE(x) do { } while (0)
397#define STATS_INC_ALLOCED(x) do { } while (0)
398#define STATS_INC_GROWN(x) do { } while (0)
399#define STATS_INC_REAPED(x) do { } while (0)
400#define STATS_SET_HIGH(x) do { } while (0)
401#define STATS_INC_ERR(x) do { } while (0)
402#define STATS_INC_NODEALLOCS(x) do { } while (0)
403#define STATS_SET_FREEABLE(x, i) \
404 do { } while (0)
405
406#define STATS_INC_ALLOCHIT(x) do { } while (0)
407#define STATS_INC_ALLOCMISS(x) do { } while (0)
408#define STATS_INC_FREEHIT(x) do { } while (0)
409#define STATS_INC_FREEMISS(x) do { } while (0)
410#endif
411
412#if DEBUG
413/* Magic nums for obj red zoning.
414 * Placed in the first word before and the first word after an obj.
415 */
416#define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */
417#define RED_ACTIVE 0x170FC2A5UL /* when obj is active */
418
419/* ...and for poisoning */
420#define POISON_INUSE 0x5a /* for use-uninitialised poisoning */
421#define POISON_FREE 0x6b /* for use-after-free poisoning */
422#define POISON_END 0xa5 /* end-byte of poisoning */
423
424/* memory layout of objects:
425 * 0 : objp
426 * 0 .. cachep->dbghead - BYTES_PER_WORD - 1: padding. This ensures that
427 * the end of an object is aligned with the end of the real
428 * allocation. Catches writes behind the end of the allocation.
429 * cachep->dbghead - BYTES_PER_WORD .. cachep->dbghead - 1:
430 * redzone word.
431 * cachep->dbghead: The real object.
432 * cachep->objsize - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
433 * cachep->objsize - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long]
434 */
435static int obj_dbghead(kmem_cache_t *cachep)
436{
437 return cachep->dbghead;
438}
439
440static int obj_reallen(kmem_cache_t *cachep)
441{
442 return cachep->reallen;
443}
444
445static unsigned long *dbg_redzone1(kmem_cache_t *cachep, void *objp)
446{
447 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
448 return (unsigned long*) (objp+obj_dbghead(cachep)-BYTES_PER_WORD);
449}
450
451static unsigned long *dbg_redzone2(kmem_cache_t *cachep, void *objp)
452{
453 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
454 if (cachep->flags & SLAB_STORE_USER)
455 return (unsigned long*) (objp+cachep->objsize-2*BYTES_PER_WORD);
456 return (unsigned long*) (objp+cachep->objsize-BYTES_PER_WORD);
457}
458
459static void **dbg_userword(kmem_cache_t *cachep, void *objp)
460{
461 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
462 return (void**)(objp+cachep->objsize-BYTES_PER_WORD);
463}
464
465#else
466
467#define obj_dbghead(x) 0
468#define obj_reallen(cachep) (cachep->objsize)
469#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;})
470#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;})
471#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
472
473#endif
474
475/*
476 * Maximum size of an obj (in 2^order pages)
477 * and absolute limit for the gfp order.
478 */
479#if defined(CONFIG_LARGE_ALLOCS)
480#define MAX_OBJ_ORDER 13 /* up to 32Mb */
481#define MAX_GFP_ORDER 13 /* up to 32Mb */
482#elif defined(CONFIG_MMU)
483#define MAX_OBJ_ORDER 5 /* 32 pages */
484#define MAX_GFP_ORDER 5 /* 32 pages */
485#else
486#define MAX_OBJ_ORDER 8 /* up to 1Mb */
487#define MAX_GFP_ORDER 8 /* up to 1Mb */
488#endif
489
490/*
491 * Do not go above this order unless 0 objects fit into the slab.
492 */
493#define BREAK_GFP_ORDER_HI 1
494#define BREAK_GFP_ORDER_LO 0
495static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
496
497/* Macros for storing/retrieving the cachep and or slab from the
498 * global 'mem_map'. These are used to find the slab an obj belongs to.
499 * With kfree(), these are used to find the cache which an obj belongs to.
500 */
501#define SET_PAGE_CACHE(pg,x) ((pg)->lru.next = (struct list_head *)(x))
502#define GET_PAGE_CACHE(pg) ((kmem_cache_t *)(pg)->lru.next)
503#define SET_PAGE_SLAB(pg,x) ((pg)->lru.prev = (struct list_head *)(x))
504#define GET_PAGE_SLAB(pg) ((struct slab *)(pg)->lru.prev)
505
506/* These are the default caches for kmalloc. Custom caches can have other sizes. */
507struct cache_sizes malloc_sizes[] = {
508#define CACHE(x) { .cs_size = (x) },
509#include <linux/kmalloc_sizes.h>
510 CACHE(ULONG_MAX)
511#undef CACHE
512};
513EXPORT_SYMBOL(malloc_sizes);
514
515/* Must match cache_sizes above. Out of line to keep cache footprint low. */
516struct cache_names {
517 char *name;
518 char *name_dma;
519};
520
521static struct cache_names __initdata cache_names[] = {
522#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
523#include <linux/kmalloc_sizes.h>
524 { NULL, }
525#undef CACHE
526};
527
528static struct arraycache_init initarray_cache __initdata =
529 { { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
530static struct arraycache_init initarray_generic =
531 { { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
532
533/* internal cache of cache description objs */
534static kmem_cache_t cache_cache = {
535 .lists = LIST3_INIT(cache_cache.lists),
536 .batchcount = 1,
537 .limit = BOOT_CPUCACHE_ENTRIES,
538 .objsize = sizeof(kmem_cache_t),
539 .flags = SLAB_NO_REAP,
540 .spinlock = SPIN_LOCK_UNLOCKED,
541 .name = "kmem_cache",
542#if DEBUG
543 .reallen = sizeof(kmem_cache_t),
544#endif
545};
546
547/* Guard access to the cache-chain. */
548static struct semaphore cache_chain_sem;
549static struct list_head cache_chain;
550
551/*
552 * vm_enough_memory() looks at this to determine how many
553 * slab-allocated pages are possibly freeable under pressure
554 *
555 * SLAB_RECLAIM_ACCOUNT turns this on per-slab
556 */
557atomic_t slab_reclaim_pages;
558EXPORT_SYMBOL(slab_reclaim_pages);
559
560/*
561 * chicken and egg problem: delay the per-cpu array allocation
562 * until the general caches are up.
563 */
564static enum {
565 NONE,
566 PARTIAL,
567 FULL
568} g_cpucache_up;
569
570static DEFINE_PER_CPU(struct work_struct, reap_work);
571
572static void free_block(kmem_cache_t* cachep, void** objpp, int len);
573static void enable_cpucache (kmem_cache_t *cachep);
574static void cache_reap (void *unused);
575
576static inline void **ac_entry(struct array_cache *ac)
577{
578 return (void**)(ac+1);
579}
580
581static inline struct array_cache *ac_data(kmem_cache_t *cachep)
582{
583 return cachep->array[smp_processor_id()];
584}
585
586static inline kmem_cache_t *kmem_find_general_cachep(size_t size, int gfpflags)
587{
588 struct cache_sizes *csizep = malloc_sizes;
589
590#if DEBUG
591 /* This happens if someone tries to call
592 * kmem_cache_create(), or __kmalloc(), before
593 * the generic caches are initialized.
594 */
595 BUG_ON(csizep->cs_cachep == NULL);
596#endif
597 while (size > csizep->cs_size)
598 csizep++;
599
600 /*
601 * Really subtile: The last entry with cs->cs_size==ULONG_MAX
602 * has cs_{dma,}cachep==NULL. Thus no special case
603 * for large kmalloc calls required.
604 */
605 if (unlikely(gfpflags & GFP_DMA))
606 return csizep->cs_dmacachep;
607 return csizep->cs_cachep;
608}
609
610/* Cal the num objs, wastage, and bytes left over for a given slab size. */
611static void cache_estimate(unsigned long gfporder, size_t size, size_t align,
612 int flags, size_t *left_over, unsigned int *num)
613{
614 int i;
615 size_t wastage = PAGE_SIZE<<gfporder;
616 size_t extra = 0;
617 size_t base = 0;
618
619 if (!(flags & CFLGS_OFF_SLAB)) {
620 base = sizeof(struct slab);
621 extra = sizeof(kmem_bufctl_t);
622 }
623 i = 0;
624 while (i*size + ALIGN(base+i*extra, align) <= wastage)
625 i++;
626 if (i > 0)
627 i--;
628
629 if (i > SLAB_LIMIT)
630 i = SLAB_LIMIT;
631
632 *num = i;
633 wastage -= i*size;
634 wastage -= ALIGN(base+i*extra, align);
635 *left_over = wastage;
636}
637
638#define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
639
640static void __slab_error(const char *function, kmem_cache_t *cachep, char *msg)
641{
642 printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
643 function, cachep->name, msg);
644 dump_stack();
645}
646
647/*
648 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
649 * via the workqueue/eventd.
650 * Add the CPU number into the expiration time to minimize the possibility of
651 * the CPUs getting into lockstep and contending for the global cache chain
652 * lock.
653 */
654static void __devinit start_cpu_timer(int cpu)
655{
656 struct work_struct *reap_work = &per_cpu(reap_work, cpu);
657
658 /*
659 * When this gets called from do_initcalls via cpucache_init(),
660 * init_workqueues() has already run, so keventd will be setup
661 * at that time.
662 */
663 if (keventd_up() && reap_work->func == NULL) {
664 INIT_WORK(reap_work, cache_reap, NULL);
665 schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
666 }
667}
668
669static struct array_cache *alloc_arraycache(int cpu, int entries,
670 int batchcount)
671{
672 int memsize = sizeof(void*)*entries+sizeof(struct array_cache);
673 struct array_cache *nc = NULL;
674
675 if (cpu != -1) {
676 kmem_cache_t *cachep;
677 cachep = kmem_find_general_cachep(memsize, GFP_KERNEL);
678 if (cachep)
679 nc = kmem_cache_alloc_node(cachep, cpu_to_node(cpu));
680 }
681 if (!nc)
682 nc = kmalloc(memsize, GFP_KERNEL);
683 if (nc) {
684 nc->avail = 0;
685 nc->limit = entries;
686 nc->batchcount = batchcount;
687 nc->touched = 0;
688 }
689 return nc;
690}
691
692static int __devinit cpuup_callback(struct notifier_block *nfb,
693 unsigned long action, void *hcpu)
694{
695 long cpu = (long)hcpu;
696 kmem_cache_t* cachep;
697
698 switch (action) {
699 case CPU_UP_PREPARE:
700 down(&cache_chain_sem);
701 list_for_each_entry(cachep, &cache_chain, next) {
702 struct array_cache *nc;
703
704 nc = alloc_arraycache(cpu, cachep->limit, cachep->batchcount);
705 if (!nc)
706 goto bad;
707
708 spin_lock_irq(&cachep->spinlock);
709 cachep->array[cpu] = nc;
710 cachep->free_limit = (1+num_online_cpus())*cachep->batchcount
711 + cachep->num;
712 spin_unlock_irq(&cachep->spinlock);
713
714 }
715 up(&cache_chain_sem);
716 break;
717 case CPU_ONLINE:
718 start_cpu_timer(cpu);
719 break;
720#ifdef CONFIG_HOTPLUG_CPU
721 case CPU_DEAD:
722 /* fall thru */
723 case CPU_UP_CANCELED:
724 down(&cache_chain_sem);
725
726 list_for_each_entry(cachep, &cache_chain, next) {
727 struct array_cache *nc;
728
729 spin_lock_irq(&cachep->spinlock);
730 /* cpu is dead; no one can alloc from it. */
731 nc = cachep->array[cpu];
732 cachep->array[cpu] = NULL;
733 cachep->free_limit -= cachep->batchcount;
734 free_block(cachep, ac_entry(nc), nc->avail);
735 spin_unlock_irq(&cachep->spinlock);
736 kfree(nc);
737 }
738 up(&cache_chain_sem);
739 break;
740#endif
741 }
742 return NOTIFY_OK;
743bad:
744 up(&cache_chain_sem);
745 return NOTIFY_BAD;
746}
747
748static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 };
749
750/* Initialisation.
751 * Called after the gfp() functions have been enabled, and before smp_init().
752 */
753void __init kmem_cache_init(void)
754{
755 size_t left_over;
756 struct cache_sizes *sizes;
757 struct cache_names *names;
758
759 /*
760 * Fragmentation resistance on low memory - only use bigger
761 * page orders on machines with more than 32MB of memory.
762 */
763 if (num_physpages > (32 << 20) >> PAGE_SHIFT)
764 slab_break_gfp_order = BREAK_GFP_ORDER_HI;
765
766
767 /* Bootstrap is tricky, because several objects are allocated
768 * from caches that do not exist yet:
769 * 1) initialize the cache_cache cache: it contains the kmem_cache_t
770 * structures of all caches, except cache_cache itself: cache_cache
771 * is statically allocated.
772 * Initially an __init data area is used for the head array, it's
773 * replaced with a kmalloc allocated array at the end of the bootstrap.
774 * 2) Create the first kmalloc cache.
775 * The kmem_cache_t for the new cache is allocated normally. An __init
776 * data area is used for the head array.
777 * 3) Create the remaining kmalloc caches, with minimally sized head arrays.
778 * 4) Replace the __init data head arrays for cache_cache and the first
779 * kmalloc cache with kmalloc allocated arrays.
780 * 5) Resize the head arrays of the kmalloc caches to their final sizes.
781 */
782
783 /* 1) create the cache_cache */
784 init_MUTEX(&cache_chain_sem);
785 INIT_LIST_HEAD(&cache_chain);
786 list_add(&cache_cache.next, &cache_chain);
787 cache_cache.colour_off = cache_line_size();
788 cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
789
790 cache_cache.objsize = ALIGN(cache_cache.objsize, cache_line_size());
791
792 cache_estimate(0, cache_cache.objsize, cache_line_size(), 0,
793 &left_over, &cache_cache.num);
794 if (!cache_cache.num)
795 BUG();
796
797 cache_cache.colour = left_over/cache_cache.colour_off;
798 cache_cache.colour_next = 0;
799 cache_cache.slab_size = ALIGN(cache_cache.num*sizeof(kmem_bufctl_t) +
800 sizeof(struct slab), cache_line_size());
801
802 /* 2+3) create the kmalloc caches */
803 sizes = malloc_sizes;
804 names = cache_names;
805
806 while (sizes->cs_size != ULONG_MAX) {
807 /* For performance, all the general caches are L1 aligned.
808 * This should be particularly beneficial on SMP boxes, as it
809 * eliminates "false sharing".
810 * Note for systems short on memory removing the alignment will
811 * allow tighter packing of the smaller caches. */
812 sizes->cs_cachep = kmem_cache_create(names->name,
813 sizes->cs_size, ARCH_KMALLOC_MINALIGN,
814 (ARCH_KMALLOC_FLAGS | SLAB_PANIC), NULL, NULL);
815
816 /* Inc off-slab bufctl limit until the ceiling is hit. */
817 if (!(OFF_SLAB(sizes->cs_cachep))) {
818 offslab_limit = sizes->cs_size-sizeof(struct slab);
819 offslab_limit /= sizeof(kmem_bufctl_t);
820 }
821
822 sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
823 sizes->cs_size, ARCH_KMALLOC_MINALIGN,
824 (ARCH_KMALLOC_FLAGS | SLAB_CACHE_DMA | SLAB_PANIC),
825 NULL, NULL);
826
827 sizes++;
828 names++;
829 }
830 /* 4) Replace the bootstrap head arrays */
831 {
832 void * ptr;
833
834 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
835 local_irq_disable();
836 BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache);
837 memcpy(ptr, ac_data(&cache_cache), sizeof(struct arraycache_init));
838 cache_cache.array[smp_processor_id()] = ptr;
839 local_irq_enable();
840
841 ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
842 local_irq_disable();
843 BUG_ON(ac_data(malloc_sizes[0].cs_cachep) != &initarray_generic.cache);
844 memcpy(ptr, ac_data(malloc_sizes[0].cs_cachep),
845 sizeof(struct arraycache_init));
846 malloc_sizes[0].cs_cachep->array[smp_processor_id()] = ptr;
847 local_irq_enable();
848 }
849
850 /* 5) resize the head arrays to their final sizes */
851 {
852 kmem_cache_t *cachep;
853 down(&cache_chain_sem);
854 list_for_each_entry(cachep, &cache_chain, next)
855 enable_cpucache(cachep);
856 up(&cache_chain_sem);
857 }
858
859 /* Done! */
860 g_cpucache_up = FULL;
861
862 /* Register a cpu startup notifier callback
863 * that initializes ac_data for all new cpus
864 */
865 register_cpu_notifier(&cpucache_notifier);
866
867
868 /* The reap timers are started later, with a module init call:
869 * That part of the kernel is not yet operational.
870 */
871}
872
873static int __init cpucache_init(void)
874{
875 int cpu;
876
877 /*
878 * Register the timers that return unneeded
879 * pages to gfp.
880 */
881 for (cpu = 0; cpu < NR_CPUS; cpu++) {
882 if (cpu_online(cpu))
883 start_cpu_timer(cpu);
884 }
885
886 return 0;
887}
888
889__initcall(cpucache_init);
890
891/*
892 * Interface to system's page allocator. No need to hold the cache-lock.
893 *
894 * If we requested dmaable memory, we will get it. Even if we
895 * did not request dmaable memory, we might get it, but that
896 * would be relatively rare and ignorable.
897 */
898static void *kmem_getpages(kmem_cache_t *cachep, unsigned int __nocast flags, int nodeid)
899{
900 struct page *page;
901 void *addr;
902 int i;
903
904 flags |= cachep->gfpflags;
905 if (likely(nodeid == -1)) {
906 page = alloc_pages(flags, cachep->gfporder);
907 } else {
908 page = alloc_pages_node(nodeid, flags, cachep->gfporder);
909 }
910 if (!page)
911 return NULL;
912 addr = page_address(page);
913
914 i = (1 << cachep->gfporder);
915 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
916 atomic_add(i, &slab_reclaim_pages);
917 add_page_state(nr_slab, i);
918 while (i--) {
919 SetPageSlab(page);
920 page++;
921 }
922 return addr;
923}
924
925/*
926 * Interface to system's page release.
927 */
928static void kmem_freepages(kmem_cache_t *cachep, void *addr)
929{
930 unsigned long i = (1<<cachep->gfporder);
931 struct page *page = virt_to_page(addr);
932 const unsigned long nr_freed = i;
933
934 while (i--) {
935 if (!TestClearPageSlab(page))
936 BUG();
937 page++;
938 }
939 sub_page_state(nr_slab, nr_freed);
940 if (current->reclaim_state)
941 current->reclaim_state->reclaimed_slab += nr_freed;
942 free_pages((unsigned long)addr, cachep->gfporder);
943 if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
944 atomic_sub(1<<cachep->gfporder, &slab_reclaim_pages);
945}
946
947static void kmem_rcu_free(struct rcu_head *head)
948{
949 struct slab_rcu *slab_rcu = (struct slab_rcu *) head;
950 kmem_cache_t *cachep = slab_rcu->cachep;
951
952 kmem_freepages(cachep, slab_rcu->addr);
953 if (OFF_SLAB(cachep))
954 kmem_cache_free(cachep->slabp_cache, slab_rcu);
955}
956
957#if DEBUG
958
959#ifdef CONFIG_DEBUG_PAGEALLOC
960static void store_stackinfo(kmem_cache_t *cachep, unsigned long *addr,
961 unsigned long caller)
962{
963 int size = obj_reallen(cachep);
964
965 addr = (unsigned long *)&((char*)addr)[obj_dbghead(cachep)];
966
967 if (size < 5*sizeof(unsigned long))
968 return;
969
970 *addr++=0x12345678;
971 *addr++=caller;
972 *addr++=smp_processor_id();
973 size -= 3*sizeof(unsigned long);
974 {
975 unsigned long *sptr = &caller;
976 unsigned long svalue;
977
978 while (!kstack_end(sptr)) {
979 svalue = *sptr++;
980 if (kernel_text_address(svalue)) {
981 *addr++=svalue;
982 size -= sizeof(unsigned long);
983 if (size <= sizeof(unsigned long))
984 break;
985 }
986 }
987
988 }
989 *addr++=0x87654321;
990}
991#endif
992
993static void poison_obj(kmem_cache_t *cachep, void *addr, unsigned char val)
994{
995 int size = obj_reallen(cachep);
996 addr = &((char*)addr)[obj_dbghead(cachep)];
997
998 memset(addr, val, size);
999 *(unsigned char *)(addr+size-1) = POISON_END;
1000}
1001
1002static void dump_line(char *data, int offset, int limit)
1003{
1004 int i;
1005 printk(KERN_ERR "%03x:", offset);
1006 for (i=0;i<limit;i++) {
1007 printk(" %02x", (unsigned char)data[offset+i]);
1008 }
1009 printk("\n");
1010}
1011#endif
1012
1013#if DEBUG
1014
1015static void print_objinfo(kmem_cache_t *cachep, void *objp, int lines)
1016{
1017 int i, size;
1018 char *realobj;
1019
1020 if (cachep->flags & SLAB_RED_ZONE) {
1021 printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n",
1022 *dbg_redzone1(cachep, objp),
1023 *dbg_redzone2(cachep, objp));
1024 }
1025
1026 if (cachep->flags & SLAB_STORE_USER) {
1027 printk(KERN_ERR "Last user: [<%p>]",
1028 *dbg_userword(cachep, objp));
1029 print_symbol("(%s)",
1030 (unsigned long)*dbg_userword(cachep, objp));
1031 printk("\n");
1032 }
1033 realobj = (char*)objp+obj_dbghead(cachep);
1034 size = obj_reallen(cachep);
1035 for (i=0; i<size && lines;i+=16, lines--) {
1036 int limit;
1037 limit = 16;
1038 if (i+limit > size)
1039 limit = size-i;
1040 dump_line(realobj, i, limit);
1041 }
1042}
1043
1044static void check_poison_obj(kmem_cache_t *cachep, void *objp)
1045{
1046 char *realobj;
1047 int size, i;
1048 int lines = 0;
1049
1050 realobj = (char*)objp+obj_dbghead(cachep);
1051 size = obj_reallen(cachep);
1052
1053 for (i=0;i<size;i++) {
1054 char exp = POISON_FREE;
1055 if (i == size-1)
1056 exp = POISON_END;
1057 if (realobj[i] != exp) {
1058 int limit;
1059 /* Mismatch ! */
1060 /* Print header */
1061 if (lines == 0) {
1062 printk(KERN_ERR "Slab corruption: start=%p, len=%d\n",
1063 realobj, size);
1064 print_objinfo(cachep, objp, 0);
1065 }
1066 /* Hexdump the affected line */
1067 i = (i/16)*16;
1068 limit = 16;
1069 if (i+limit > size)
1070 limit = size-i;
1071 dump_line(realobj, i, limit);
1072 i += 16;
1073 lines++;
1074 /* Limit to 5 lines */
1075 if (lines > 5)
1076 break;
1077 }
1078 }
1079 if (lines != 0) {
1080 /* Print some data about the neighboring objects, if they
1081 * exist:
1082 */
1083 struct slab *slabp = GET_PAGE_SLAB(virt_to_page(objp));
1084 int objnr;
1085
1086 objnr = (objp-slabp->s_mem)/cachep->objsize;
1087 if (objnr) {
1088 objp = slabp->s_mem+(objnr-1)*cachep->objsize;
1089 realobj = (char*)objp+obj_dbghead(cachep);
1090 printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
1091 realobj, size);
1092 print_objinfo(cachep, objp, 2);
1093 }
1094 if (objnr+1 < cachep->num) {
1095 objp = slabp->s_mem+(objnr+1)*cachep->objsize;
1096 realobj = (char*)objp+obj_dbghead(cachep);
1097 printk(KERN_ERR "Next obj: start=%p, len=%d\n",
1098 realobj, size);
1099 print_objinfo(cachep, objp, 2);
1100 }
1101 }
1102}
1103#endif
1104
1105/* Destroy all the objs in a slab, and release the mem back to the system.
1106 * Before calling the slab must have been unlinked from the cache.
1107 * The cache-lock is not held/needed.
1108 */
1109static void slab_destroy (kmem_cache_t *cachep, struct slab *slabp)
1110{
1111 void *addr = slabp->s_mem - slabp->colouroff;
1112
1113#if DEBUG
1114 int i;
1115 for (i = 0; i < cachep->num; i++) {
1116 void *objp = slabp->s_mem + cachep->objsize * i;
1117
1118 if (cachep->flags & SLAB_POISON) {
1119#ifdef CONFIG_DEBUG_PAGEALLOC
1120 if ((cachep->objsize%PAGE_SIZE)==0 && OFF_SLAB(cachep))
1121 kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE,1);
1122 else
1123 check_poison_obj(cachep, objp);
1124#else
1125 check_poison_obj(cachep, objp);
1126#endif
1127 }
1128 if (cachep->flags & SLAB_RED_ZONE) {
1129 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1130 slab_error(cachep, "start of a freed object "
1131 "was overwritten");
1132 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1133 slab_error(cachep, "end of a freed object "
1134 "was overwritten");
1135 }
1136 if (cachep->dtor && !(cachep->flags & SLAB_POISON))
1137 (cachep->dtor)(objp+obj_dbghead(cachep), cachep, 0);
1138 }
1139#else
1140 if (cachep->dtor) {
1141 int i;
1142 for (i = 0; i < cachep->num; i++) {
1143 void* objp = slabp->s_mem+cachep->objsize*i;
1144 (cachep->dtor)(objp, cachep, 0);
1145 }
1146 }
1147#endif
1148
1149 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) {
1150 struct slab_rcu *slab_rcu;
1151
1152 slab_rcu = (struct slab_rcu *) slabp;
1153 slab_rcu->cachep = cachep;
1154 slab_rcu->addr = addr;
1155 call_rcu(&slab_rcu->head, kmem_rcu_free);
1156 } else {
1157 kmem_freepages(cachep, addr);
1158 if (OFF_SLAB(cachep))
1159 kmem_cache_free(cachep->slabp_cache, slabp);
1160 }
1161}
1162
1163/**
1164 * kmem_cache_create - Create a cache.
1165 * @name: A string which is used in /proc/slabinfo to identify this cache.
1166 * @size: The size of objects to be created in this cache.
1167 * @align: The required alignment for the objects.
1168 * @flags: SLAB flags
1169 * @ctor: A constructor for the objects.
1170 * @dtor: A destructor for the objects.
1171 *
1172 * Returns a ptr to the cache on success, NULL on failure.
1173 * Cannot be called within a int, but can be interrupted.
1174 * The @ctor is run when new pages are allocated by the cache
1175 * and the @dtor is run before the pages are handed back.
1176 *
1177 * @name must be valid until the cache is destroyed. This implies that
1178 * the module calling this has to destroy the cache before getting
1179 * unloaded.
1180 *
1181 * The flags are
1182 *
1183 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1184 * to catch references to uninitialised memory.
1185 *
1186 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1187 * for buffer overruns.
1188 *
1189 * %SLAB_NO_REAP - Don't automatically reap this cache when we're under
1190 * memory pressure.
1191 *
1192 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1193 * cacheline. This can be beneficial if you're counting cycles as closely
1194 * as davem.
1195 */
1196kmem_cache_t *
1197kmem_cache_create (const char *name, size_t size, size_t align,
1198 unsigned long flags, void (*ctor)(void*, kmem_cache_t *, unsigned long),
1199 void (*dtor)(void*, kmem_cache_t *, unsigned long))
1200{
1201 size_t left_over, slab_size, ralign;
1202 kmem_cache_t *cachep = NULL;
1203
1204 /*
1205 * Sanity checks... these are all serious usage bugs.
1206 */
1207 if ((!name) ||
1208 in_interrupt() ||
1209 (size < BYTES_PER_WORD) ||
1210 (size > (1<<MAX_OBJ_ORDER)*PAGE_SIZE) ||
1211 (dtor && !ctor)) {
1212 printk(KERN_ERR "%s: Early error in slab %s\n",
1213 __FUNCTION__, name);
1214 BUG();
1215 }
1216
1217#if DEBUG
1218 WARN_ON(strchr(name, ' ')); /* It confuses parsers */
1219 if ((flags & SLAB_DEBUG_INITIAL) && !ctor) {
1220 /* No constructor, but inital state check requested */
1221 printk(KERN_ERR "%s: No con, but init state check "
1222 "requested - %s\n", __FUNCTION__, name);
1223 flags &= ~SLAB_DEBUG_INITIAL;
1224 }
1225
1226#if FORCED_DEBUG
1227 /*
1228 * Enable redzoning and last user accounting, except for caches with
1229 * large objects, if the increased size would increase the object size
1230 * above the next power of two: caches with object sizes just above a
1231 * power of two have a significant amount of internal fragmentation.
1232 */
1233 if ((size < 4096 || fls(size-1) == fls(size-1+3*BYTES_PER_WORD)))
1234 flags |= SLAB_RED_ZONE|SLAB_STORE_USER;
1235 if (!(flags & SLAB_DESTROY_BY_RCU))
1236 flags |= SLAB_POISON;
1237#endif
1238 if (flags & SLAB_DESTROY_BY_RCU)
1239 BUG_ON(flags & SLAB_POISON);
1240#endif
1241 if (flags & SLAB_DESTROY_BY_RCU)
1242 BUG_ON(dtor);
1243
1244 /*
1245 * Always checks flags, a caller might be expecting debug
1246 * support which isn't available.
1247 */
1248 if (flags & ~CREATE_MASK)
1249 BUG();
1250
1251 /* Check that size is in terms of words. This is needed to avoid
1252 * unaligned accesses for some archs when redzoning is used, and makes
1253 * sure any on-slab bufctl's are also correctly aligned.
1254 */
1255 if (size & (BYTES_PER_WORD-1)) {
1256 size += (BYTES_PER_WORD-1);
1257 size &= ~(BYTES_PER_WORD-1);
1258 }
1259
1260 /* calculate out the final buffer alignment: */
1261 /* 1) arch recommendation: can be overridden for debug */
1262 if (flags & SLAB_HWCACHE_ALIGN) {
1263 /* Default alignment: as specified by the arch code.
1264 * Except if an object is really small, then squeeze multiple
1265 * objects into one cacheline.
1266 */
1267 ralign = cache_line_size();
1268 while (size <= ralign/2)
1269 ralign /= 2;
1270 } else {
1271 ralign = BYTES_PER_WORD;
1272 }
1273 /* 2) arch mandated alignment: disables debug if necessary */
1274 if (ralign < ARCH_SLAB_MINALIGN) {
1275 ralign = ARCH_SLAB_MINALIGN;
1276 if (ralign > BYTES_PER_WORD)
1277 flags &= ~(SLAB_RED_ZONE|SLAB_STORE_USER);
1278 }
1279 /* 3) caller mandated alignment: disables debug if necessary */
1280 if (ralign < align) {
1281 ralign = align;
1282 if (ralign > BYTES_PER_WORD)
1283 flags &= ~(SLAB_RED_ZONE|SLAB_STORE_USER);
1284 }
1285 /* 4) Store it. Note that the debug code below can reduce
1286 * the alignment to BYTES_PER_WORD.
1287 */
1288 align = ralign;
1289
1290 /* Get cache's description obj. */
1291 cachep = (kmem_cache_t *) kmem_cache_alloc(&cache_cache, SLAB_KERNEL);
1292 if (!cachep)
1293 goto opps;
1294 memset(cachep, 0, sizeof(kmem_cache_t));
1295
1296#if DEBUG
1297 cachep->reallen = size;
1298
1299 if (flags & SLAB_RED_ZONE) {
1300 /* redzoning only works with word aligned caches */
1301 align = BYTES_PER_WORD;
1302
1303 /* add space for red zone words */
1304 cachep->dbghead += BYTES_PER_WORD;
1305 size += 2*BYTES_PER_WORD;
1306 }
1307 if (flags & SLAB_STORE_USER) {
1308 /* user store requires word alignment and
1309 * one word storage behind the end of the real
1310 * object.
1311 */
1312 align = BYTES_PER_WORD;
1313 size += BYTES_PER_WORD;
1314 }
1315#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
1316 if (size > 128 && cachep->reallen > cache_line_size() && size < PAGE_SIZE) {
1317 cachep->dbghead += PAGE_SIZE - size;
1318 size = PAGE_SIZE;
1319 }
1320#endif
1321#endif
1322
1323 /* Determine if the slab management is 'on' or 'off' slab. */
1324 if (size >= (PAGE_SIZE>>3))
1325 /*
1326 * Size is large, assume best to place the slab management obj
1327 * off-slab (should allow better packing of objs).
1328 */
1329 flags |= CFLGS_OFF_SLAB;
1330
1331 size = ALIGN(size, align);
1332
1333 if ((flags & SLAB_RECLAIM_ACCOUNT) && size <= PAGE_SIZE) {
1334 /*
1335 * A VFS-reclaimable slab tends to have most allocations
1336 * as GFP_NOFS and we really don't want to have to be allocating
1337 * higher-order pages when we are unable to shrink dcache.
1338 */
1339 cachep->gfporder = 0;
1340 cache_estimate(cachep->gfporder, size, align, flags,
1341 &left_over, &cachep->num);
1342 } else {
1343 /*
1344 * Calculate size (in pages) of slabs, and the num of objs per
1345 * slab. This could be made much more intelligent. For now,
1346 * try to avoid using high page-orders for slabs. When the
1347 * gfp() funcs are more friendly towards high-order requests,
1348 * this should be changed.
1349 */
1350 do {
1351 unsigned int break_flag = 0;
1352cal_wastage:
1353 cache_estimate(cachep->gfporder, size, align, flags,
1354 &left_over, &cachep->num);
1355 if (break_flag)
1356 break;
1357 if (cachep->gfporder >= MAX_GFP_ORDER)
1358 break;
1359 if (!cachep->num)
1360 goto next;
1361 if (flags & CFLGS_OFF_SLAB &&
1362 cachep->num > offslab_limit) {
1363 /* This num of objs will cause problems. */
1364 cachep->gfporder--;
1365 break_flag++;
1366 goto cal_wastage;
1367 }
1368
1369 /*
1370 * Large num of objs is good, but v. large slabs are
1371 * currently bad for the gfp()s.
1372 */
1373 if (cachep->gfporder >= slab_break_gfp_order)
1374 break;
1375
1376 if ((left_over*8) <= (PAGE_SIZE<<cachep->gfporder))
1377 break; /* Acceptable internal fragmentation. */
1378next:
1379 cachep->gfporder++;
1380 } while (1);
1381 }
1382
1383 if (!cachep->num) {
1384 printk("kmem_cache_create: couldn't create cache %s.\n", name);
1385 kmem_cache_free(&cache_cache, cachep);
1386 cachep = NULL;
1387 goto opps;
1388 }
1389 slab_size = ALIGN(cachep->num*sizeof(kmem_bufctl_t)
1390 + sizeof(struct slab), align);
1391
1392 /*
1393 * If the slab has been placed off-slab, and we have enough space then
1394 * move it on-slab. This is at the expense of any extra colouring.
1395 */
1396 if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) {
1397 flags &= ~CFLGS_OFF_SLAB;
1398 left_over -= slab_size;
1399 }
1400
1401 if (flags & CFLGS_OFF_SLAB) {
1402 /* really off slab. No need for manual alignment */
1403 slab_size = cachep->num*sizeof(kmem_bufctl_t)+sizeof(struct slab);
1404 }
1405
1406 cachep->colour_off = cache_line_size();
1407 /* Offset must be a multiple of the alignment. */
1408 if (cachep->colour_off < align)
1409 cachep->colour_off = align;
1410 cachep->colour = left_over/cachep->colour_off;
1411 cachep->slab_size = slab_size;
1412 cachep->flags = flags;
1413 cachep->gfpflags = 0;
1414 if (flags & SLAB_CACHE_DMA)
1415 cachep->gfpflags |= GFP_DMA;
1416 spin_lock_init(&cachep->spinlock);
1417 cachep->objsize = size;
1418 /* NUMA */
1419 INIT_LIST_HEAD(&cachep->lists.slabs_full);
1420 INIT_LIST_HEAD(&cachep->lists.slabs_partial);
1421 INIT_LIST_HEAD(&cachep->lists.slabs_free);
1422
1423 if (flags & CFLGS_OFF_SLAB)
1424 cachep->slabp_cache = kmem_find_general_cachep(slab_size,0);
1425 cachep->ctor = ctor;
1426 cachep->dtor = dtor;
1427 cachep->name = name;
1428
1429 /* Don't let CPUs to come and go */
1430 lock_cpu_hotplug();
1431
1432 if (g_cpucache_up == FULL) {
1433 enable_cpucache(cachep);
1434 } else {
1435 if (g_cpucache_up == NONE) {
1436 /* Note: the first kmem_cache_create must create
1437 * the cache that's used by kmalloc(24), otherwise
1438 * the creation of further caches will BUG().
1439 */
1440 cachep->array[smp_processor_id()] = &initarray_generic.cache;
1441 g_cpucache_up = PARTIAL;
1442 } else {
1443 cachep->array[smp_processor_id()] = kmalloc(sizeof(struct arraycache_init),GFP_KERNEL);
1444 }
1445 BUG_ON(!ac_data(cachep));
1446 ac_data(cachep)->avail = 0;
1447 ac_data(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1448 ac_data(cachep)->batchcount = 1;
1449 ac_data(cachep)->touched = 0;
1450 cachep->batchcount = 1;
1451 cachep->limit = BOOT_CPUCACHE_ENTRIES;
1452 cachep->free_limit = (1+num_online_cpus())*cachep->batchcount
1453 + cachep->num;
1454 }
1455
1456 cachep->lists.next_reap = jiffies + REAPTIMEOUT_LIST3 +
1457 ((unsigned long)cachep)%REAPTIMEOUT_LIST3;
1458
1459 /* Need the semaphore to access the chain. */
1460 down(&cache_chain_sem);
1461 {
1462 struct list_head *p;
1463 mm_segment_t old_fs;
1464
1465 old_fs = get_fs();
1466 set_fs(KERNEL_DS);
1467 list_for_each(p, &cache_chain) {
1468 kmem_cache_t *pc = list_entry(p, kmem_cache_t, next);
1469 char tmp;
1470 /* This happens when the module gets unloaded and doesn't
1471 destroy its slab cache and noone else reuses the vmalloc
1472 area of the module. Print a warning. */
1473 if (__get_user(tmp,pc->name)) {
1474 printk("SLAB: cache with size %d has lost its name\n",
1475 pc->objsize);
1476 continue;
1477 }
1478 if (!strcmp(pc->name,name)) {
1479 printk("kmem_cache_create: duplicate cache %s\n",name);
1480 up(&cache_chain_sem);
1481 unlock_cpu_hotplug();
1482 BUG();
1483 }
1484 }
1485 set_fs(old_fs);
1486 }
1487
1488 /* cache setup completed, link it into the list */
1489 list_add(&cachep->next, &cache_chain);
1490 up(&cache_chain_sem);
1491 unlock_cpu_hotplug();
1492opps:
1493 if (!cachep && (flags & SLAB_PANIC))
1494 panic("kmem_cache_create(): failed to create slab `%s'\n",
1495 name);
1496 return cachep;
1497}
1498EXPORT_SYMBOL(kmem_cache_create);
1499
1500#if DEBUG
1501static void check_irq_off(void)
1502{
1503 BUG_ON(!irqs_disabled());
1504}
1505
1506static void check_irq_on(void)
1507{
1508 BUG_ON(irqs_disabled());
1509}
1510
1511static void check_spinlock_acquired(kmem_cache_t *cachep)
1512{
1513#ifdef CONFIG_SMP
1514 check_irq_off();
1515 BUG_ON(spin_trylock(&cachep->spinlock));
1516#endif
1517}
1518#else
1519#define check_irq_off() do { } while(0)
1520#define check_irq_on() do { } while(0)
1521#define check_spinlock_acquired(x) do { } while(0)
1522#endif
1523
1524/*
1525 * Waits for all CPUs to execute func().
1526 */
1527static void smp_call_function_all_cpus(void (*func) (void *arg), void *arg)
1528{
1529 check_irq_on();
1530 preempt_disable();
1531
1532 local_irq_disable();
1533 func(arg);
1534 local_irq_enable();
1535
1536 if (smp_call_function(func, arg, 1, 1))
1537 BUG();
1538
1539 preempt_enable();
1540}
1541
1542static void drain_array_locked(kmem_cache_t* cachep,
1543 struct array_cache *ac, int force);
1544
1545static void do_drain(void *arg)
1546{
1547 kmem_cache_t *cachep = (kmem_cache_t*)arg;
1548 struct array_cache *ac;
1549
1550 check_irq_off();
1551 ac = ac_data(cachep);
1552 spin_lock(&cachep->spinlock);
1553 free_block(cachep, &ac_entry(ac)[0], ac->avail);
1554 spin_unlock(&cachep->spinlock);
1555 ac->avail = 0;
1556}
1557
1558static void drain_cpu_caches(kmem_cache_t *cachep)
1559{
1560 smp_call_function_all_cpus(do_drain, cachep);
1561 check_irq_on();
1562 spin_lock_irq(&cachep->spinlock);
1563 if (cachep->lists.shared)
1564 drain_array_locked(cachep, cachep->lists.shared, 1);
1565 spin_unlock_irq(&cachep->spinlock);
1566}
1567
1568
1569/* NUMA shrink all list3s */
1570static int __cache_shrink(kmem_cache_t *cachep)
1571{
1572 struct slab *slabp;
1573 int ret;
1574
1575 drain_cpu_caches(cachep);
1576
1577 check_irq_on();
1578 spin_lock_irq(&cachep->spinlock);
1579
1580 for(;;) {
1581 struct list_head *p;
1582
1583 p = cachep->lists.slabs_free.prev;
1584 if (p == &cachep->lists.slabs_free)
1585 break;
1586
1587 slabp = list_entry(cachep->lists.slabs_free.prev, struct slab, list);
1588#if DEBUG
1589 if (slabp->inuse)
1590 BUG();
1591#endif
1592 list_del(&slabp->list);
1593
1594 cachep->lists.free_objects -= cachep->num;
1595 spin_unlock_irq(&cachep->spinlock);
1596 slab_destroy(cachep, slabp);
1597 spin_lock_irq(&cachep->spinlock);
1598 }
1599 ret = !list_empty(&cachep->lists.slabs_full) ||
1600 !list_empty(&cachep->lists.slabs_partial);
1601 spin_unlock_irq(&cachep->spinlock);
1602 return ret;
1603}
1604
1605/**
1606 * kmem_cache_shrink - Shrink a cache.
1607 * @cachep: The cache to shrink.
1608 *
1609 * Releases as many slabs as possible for a cache.
1610 * To help debugging, a zero exit status indicates all slabs were released.
1611 */
1612int kmem_cache_shrink(kmem_cache_t *cachep)
1613{
1614 if (!cachep || in_interrupt())
1615 BUG();
1616
1617 return __cache_shrink(cachep);
1618}
1619EXPORT_SYMBOL(kmem_cache_shrink);
1620
1621/**
1622 * kmem_cache_destroy - delete a cache
1623 * @cachep: the cache to destroy
1624 *
1625 * Remove a kmem_cache_t object from the slab cache.
1626 * Returns 0 on success.
1627 *
1628 * It is expected this function will be called by a module when it is
1629 * unloaded. This will remove the cache completely, and avoid a duplicate
1630 * cache being allocated each time a module is loaded and unloaded, if the
1631 * module doesn't have persistent in-kernel storage across loads and unloads.
1632 *
1633 * The cache must be empty before calling this function.
1634 *
1635 * The caller must guarantee that noone will allocate memory from the cache
1636 * during the kmem_cache_destroy().
1637 */
1638int kmem_cache_destroy(kmem_cache_t * cachep)
1639{
1640 int i;
1641
1642 if (!cachep || in_interrupt())
1643 BUG();
1644
1645 /* Don't let CPUs to come and go */
1646 lock_cpu_hotplug();
1647
1648 /* Find the cache in the chain of caches. */
1649 down(&cache_chain_sem);
1650 /*
1651 * the chain is never empty, cache_cache is never destroyed
1652 */
1653 list_del(&cachep->next);
1654 up(&cache_chain_sem);
1655
1656 if (__cache_shrink(cachep)) {
1657 slab_error(cachep, "Can't free all objects");
1658 down(&cache_chain_sem);
1659 list_add(&cachep->next,&cache_chain);
1660 up(&cache_chain_sem);
1661 unlock_cpu_hotplug();
1662 return 1;
1663 }
1664
1665 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
1666 synchronize_kernel();
1667
1668 /* no cpu_online check required here since we clear the percpu
1669 * array on cpu offline and set this to NULL.
1670 */
1671 for (i = 0; i < NR_CPUS; i++)
1672 kfree(cachep->array[i]);
1673
1674 /* NUMA: free the list3 structures */
1675 kfree(cachep->lists.shared);
1676 cachep->lists.shared = NULL;
1677 kmem_cache_free(&cache_cache, cachep);
1678
1679 unlock_cpu_hotplug();
1680
1681 return 0;
1682}
1683EXPORT_SYMBOL(kmem_cache_destroy);
1684
1685/* Get the memory for a slab management obj. */
1686static struct slab* alloc_slabmgmt(kmem_cache_t *cachep,
1687 void *objp, int colour_off, unsigned int __nocast local_flags)
1688{
1689 struct slab *slabp;
1690
1691 if (OFF_SLAB(cachep)) {
1692 /* Slab management obj is off-slab. */
1693 slabp = kmem_cache_alloc(cachep->slabp_cache, local_flags);
1694 if (!slabp)
1695 return NULL;
1696 } else {
1697 slabp = objp+colour_off;
1698 colour_off += cachep->slab_size;
1699 }
1700 slabp->inuse = 0;
1701 slabp->colouroff = colour_off;
1702 slabp->s_mem = objp+colour_off;
1703
1704 return slabp;
1705}
1706
1707static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
1708{
1709 return (kmem_bufctl_t *)(slabp+1);
1710}
1711
1712static void cache_init_objs(kmem_cache_t *cachep,
1713 struct slab *slabp, unsigned long ctor_flags)
1714{
1715 int i;
1716
1717 for (i = 0; i < cachep->num; i++) {
1718 void* objp = slabp->s_mem+cachep->objsize*i;
1719#if DEBUG
1720 /* need to poison the objs? */
1721 if (cachep->flags & SLAB_POISON)
1722 poison_obj(cachep, objp, POISON_FREE);
1723 if (cachep->flags & SLAB_STORE_USER)
1724 *dbg_userword(cachep, objp) = NULL;
1725
1726 if (cachep->flags & SLAB_RED_ZONE) {
1727 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
1728 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
1729 }
1730 /*
1731 * Constructors are not allowed to allocate memory from
1732 * the same cache which they are a constructor for.
1733 * Otherwise, deadlock. They must also be threaded.
1734 */
1735 if (cachep->ctor && !(cachep->flags & SLAB_POISON))
1736 cachep->ctor(objp+obj_dbghead(cachep), cachep, ctor_flags);
1737
1738 if (cachep->flags & SLAB_RED_ZONE) {
1739 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1740 slab_error(cachep, "constructor overwrote the"
1741 " end of an object");
1742 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1743 slab_error(cachep, "constructor overwrote the"
1744 " start of an object");
1745 }
1746 if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
1747 kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 0);
1748#else
1749 if (cachep->ctor)
1750 cachep->ctor(objp, cachep, ctor_flags);
1751#endif
1752 slab_bufctl(slabp)[i] = i+1;
1753 }
1754 slab_bufctl(slabp)[i-1] = BUFCTL_END;
1755 slabp->free = 0;
1756}
1757
1758static void kmem_flagcheck(kmem_cache_t *cachep, unsigned int flags)
1759{
1760 if (flags & SLAB_DMA) {
1761 if (!(cachep->gfpflags & GFP_DMA))
1762 BUG();
1763 } else {
1764 if (cachep->gfpflags & GFP_DMA)
1765 BUG();
1766 }
1767}
1768
1769static void set_slab_attr(kmem_cache_t *cachep, struct slab *slabp, void *objp)
1770{
1771 int i;
1772 struct page *page;
1773
1774 /* Nasty!!!!!! I hope this is OK. */
1775 i = 1 << cachep->gfporder;
1776 page = virt_to_page(objp);
1777 do {
1778 SET_PAGE_CACHE(page, cachep);
1779 SET_PAGE_SLAB(page, slabp);
1780 page++;
1781 } while (--i);
1782}
1783
1784/*
1785 * Grow (by 1) the number of slabs within a cache. This is called by
1786 * kmem_cache_alloc() when there are no active objs left in a cache.
1787 */
1788static int cache_grow(kmem_cache_t *cachep, unsigned int __nocast flags, int nodeid)
1789{
1790 struct slab *slabp;
1791 void *objp;
1792 size_t offset;
1793 unsigned int local_flags;
1794 unsigned long ctor_flags;
1795
1796 /* Be lazy and only check for valid flags here,
1797 * keeping it out of the critical path in kmem_cache_alloc().
1798 */
1799 if (flags & ~(SLAB_DMA|SLAB_LEVEL_MASK|SLAB_NO_GROW))
1800 BUG();
1801 if (flags & SLAB_NO_GROW)
1802 return 0;
1803
1804 ctor_flags = SLAB_CTOR_CONSTRUCTOR;
1805 local_flags = (flags & SLAB_LEVEL_MASK);
1806 if (!(local_flags & __GFP_WAIT))
1807 /*
1808 * Not allowed to sleep. Need to tell a constructor about
1809 * this - it might need to know...
1810 */
1811 ctor_flags |= SLAB_CTOR_ATOMIC;
1812
1813 /* About to mess with non-constant members - lock. */
1814 check_irq_off();
1815 spin_lock(&cachep->spinlock);
1816
1817 /* Get colour for the slab, and cal the next value. */
1818 offset = cachep->colour_next;
1819 cachep->colour_next++;
1820 if (cachep->colour_next >= cachep->colour)
1821 cachep->colour_next = 0;
1822 offset *= cachep->colour_off;
1823
1824 spin_unlock(&cachep->spinlock);
1825
1826 if (local_flags & __GFP_WAIT)
1827 local_irq_enable();
1828
1829 /*
1830 * The test for missing atomic flag is performed here, rather than
1831 * the more obvious place, simply to reduce the critical path length
1832 * in kmem_cache_alloc(). If a caller is seriously mis-behaving they
1833 * will eventually be caught here (where it matters).
1834 */
1835 kmem_flagcheck(cachep, flags);
1836
1837
1838 /* Get mem for the objs. */
1839 if (!(objp = kmem_getpages(cachep, flags, nodeid)))
1840 goto failed;
1841
1842 /* Get slab management. */
1843 if (!(slabp = alloc_slabmgmt(cachep, objp, offset, local_flags)))
1844 goto opps1;
1845
1846 set_slab_attr(cachep, slabp, objp);
1847
1848 cache_init_objs(cachep, slabp, ctor_flags);
1849
1850 if (local_flags & __GFP_WAIT)
1851 local_irq_disable();
1852 check_irq_off();
1853 spin_lock(&cachep->spinlock);
1854
1855 /* Make slab active. */
1856 list_add_tail(&slabp->list, &(list3_data(cachep)->slabs_free));
1857 STATS_INC_GROWN(cachep);
1858 list3_data(cachep)->free_objects += cachep->num;
1859 spin_unlock(&cachep->spinlock);
1860 return 1;
1861opps1:
1862 kmem_freepages(cachep, objp);
1863failed:
1864 if (local_flags & __GFP_WAIT)
1865 local_irq_disable();
1866 return 0;
1867}
1868
1869#if DEBUG
1870
1871/*
1872 * Perform extra freeing checks:
1873 * - detect bad pointers.
1874 * - POISON/RED_ZONE checking
1875 * - destructor calls, for caches with POISON+dtor
1876 */
1877static void kfree_debugcheck(const void *objp)
1878{
1879 struct page *page;
1880
1881 if (!virt_addr_valid(objp)) {
1882 printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
1883 (unsigned long)objp);
1884 BUG();
1885 }
1886 page = virt_to_page(objp);
1887 if (!PageSlab(page)) {
1888 printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n", (unsigned long)objp);
1889 BUG();
1890 }
1891}
1892
1893static void *cache_free_debugcheck(kmem_cache_t *cachep, void *objp,
1894 void *caller)
1895{
1896 struct page *page;
1897 unsigned int objnr;
1898 struct slab *slabp;
1899
1900 objp -= obj_dbghead(cachep);
1901 kfree_debugcheck(objp);
1902 page = virt_to_page(objp);
1903
1904 if (GET_PAGE_CACHE(page) != cachep) {
1905 printk(KERN_ERR "mismatch in kmem_cache_free: expected cache %p, got %p\n",
1906 GET_PAGE_CACHE(page),cachep);
1907 printk(KERN_ERR "%p is %s.\n", cachep, cachep->name);
1908 printk(KERN_ERR "%p is %s.\n", GET_PAGE_CACHE(page), GET_PAGE_CACHE(page)->name);
1909 WARN_ON(1);
1910 }
1911 slabp = GET_PAGE_SLAB(page);
1912
1913 if (cachep->flags & SLAB_RED_ZONE) {
1914 if (*dbg_redzone1(cachep, objp) != RED_ACTIVE || *dbg_redzone2(cachep, objp) != RED_ACTIVE) {
1915 slab_error(cachep, "double free, or memory outside"
1916 " object was overwritten");
1917 printk(KERN_ERR "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
1918 objp, *dbg_redzone1(cachep, objp), *dbg_redzone2(cachep, objp));
1919 }
1920 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
1921 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
1922 }
1923 if (cachep->flags & SLAB_STORE_USER)
1924 *dbg_userword(cachep, objp) = caller;
1925
1926 objnr = (objp-slabp->s_mem)/cachep->objsize;
1927
1928 BUG_ON(objnr >= cachep->num);
1929 BUG_ON(objp != slabp->s_mem + objnr*cachep->objsize);
1930
1931 if (cachep->flags & SLAB_DEBUG_INITIAL) {
1932 /* Need to call the slab's constructor so the
1933 * caller can perform a verify of its state (debugging).
1934 * Called without the cache-lock held.
1935 */
1936 cachep->ctor(objp+obj_dbghead(cachep),
1937 cachep, SLAB_CTOR_CONSTRUCTOR|SLAB_CTOR_VERIFY);
1938 }
1939 if (cachep->flags & SLAB_POISON && cachep->dtor) {
1940 /* we want to cache poison the object,
1941 * call the destruction callback
1942 */
1943 cachep->dtor(objp+obj_dbghead(cachep), cachep, 0);
1944 }
1945 if (cachep->flags & SLAB_POISON) {
1946#ifdef CONFIG_DEBUG_PAGEALLOC
1947 if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) {
1948 store_stackinfo(cachep, objp, (unsigned long)caller);
1949 kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 0);
1950 } else {
1951 poison_obj(cachep, objp, POISON_FREE);
1952 }
1953#else
1954 poison_obj(cachep, objp, POISON_FREE);
1955#endif
1956 }
1957 return objp;
1958}
1959
1960static void check_slabp(kmem_cache_t *cachep, struct slab *slabp)
1961{
1962 kmem_bufctl_t i;
1963 int entries = 0;
1964
1965 check_spinlock_acquired(cachep);
1966 /* Check slab's freelist to see if this obj is there. */
1967 for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
1968 entries++;
1969 if (entries > cachep->num || i >= cachep->num)
1970 goto bad;
1971 }
1972 if (entries != cachep->num - slabp->inuse) {
1973bad:
1974 printk(KERN_ERR "slab: Internal list corruption detected in cache '%s'(%d), slabp %p(%d). Hexdump:\n",
1975 cachep->name, cachep->num, slabp, slabp->inuse);
1976 for (i=0;i<sizeof(slabp)+cachep->num*sizeof(kmem_bufctl_t);i++) {
1977 if ((i%16)==0)
1978 printk("\n%03x:", i);
1979 printk(" %02x", ((unsigned char*)slabp)[i]);
1980 }
1981 printk("\n");
1982 BUG();
1983 }
1984}
1985#else
1986#define kfree_debugcheck(x) do { } while(0)
1987#define cache_free_debugcheck(x,objp,z) (objp)
1988#define check_slabp(x,y) do { } while(0)
1989#endif
1990
1991static void *cache_alloc_refill(kmem_cache_t *cachep, unsigned int __nocast flags)
1992{
1993 int batchcount;
1994 struct kmem_list3 *l3;
1995 struct array_cache *ac;
1996
1997 check_irq_off();
1998 ac = ac_data(cachep);
1999retry:
2000 batchcount = ac->batchcount;
2001 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2002 /* if there was little recent activity on this
2003 * cache, then perform only a partial refill.
2004 * Otherwise we could generate refill bouncing.
2005 */
2006 batchcount = BATCHREFILL_LIMIT;
2007 }
2008 l3 = list3_data(cachep);
2009
2010 BUG_ON(ac->avail > 0);
2011 spin_lock(&cachep->spinlock);
2012 if (l3->shared) {
2013 struct array_cache *shared_array = l3->shared;
2014 if (shared_array->avail) {
2015 if (batchcount > shared_array->avail)
2016 batchcount = shared_array->avail;
2017 shared_array->avail -= batchcount;
2018 ac->avail = batchcount;
2019 memcpy(ac_entry(ac), &ac_entry(shared_array)[shared_array->avail],
2020 sizeof(void*)*batchcount);
2021 shared_array->touched = 1;
2022 goto alloc_done;
2023 }
2024 }
2025 while (batchcount > 0) {
2026 struct list_head *entry;
2027 struct slab *slabp;
2028 /* Get slab alloc is to come from. */
2029 entry = l3->slabs_partial.next;
2030 if (entry == &l3->slabs_partial) {
2031 l3->free_touched = 1;
2032 entry = l3->slabs_free.next;
2033 if (entry == &l3->slabs_free)
2034 goto must_grow;
2035 }
2036
2037 slabp = list_entry(entry, struct slab, list);
2038 check_slabp(cachep, slabp);
2039 check_spinlock_acquired(cachep);
2040 while (slabp->inuse < cachep->num && batchcount--) {
2041 kmem_bufctl_t next;
2042 STATS_INC_ALLOCED(cachep);
2043 STATS_INC_ACTIVE(cachep);
2044 STATS_SET_HIGH(cachep);
2045
2046 /* get obj pointer */
2047 ac_entry(ac)[ac->avail++] = slabp->s_mem + slabp->free*cachep->objsize;
2048
2049 slabp->inuse++;
2050 next = slab_bufctl(slabp)[slabp->free];
2051#if DEBUG
2052 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2053#endif
2054 slabp->free = next;
2055 }
2056 check_slabp(cachep, slabp);
2057
2058 /* move slabp to correct slabp list: */
2059 list_del(&slabp->list);
2060 if (slabp->free == BUFCTL_END)
2061 list_add(&slabp->list, &l3->slabs_full);
2062 else
2063 list_add(&slabp->list, &l3->slabs_partial);
2064 }
2065
2066must_grow:
2067 l3->free_objects -= ac->avail;
2068alloc_done:
2069 spin_unlock(&cachep->spinlock);
2070
2071 if (unlikely(!ac->avail)) {
2072 int x;
2073 x = cache_grow(cachep, flags, -1);
2074
2075 // cache_grow can reenable interrupts, then ac could change.
2076 ac = ac_data(cachep);
2077 if (!x && ac->avail == 0) // no objects in sight? abort
2078 return NULL;
2079
2080 if (!ac->avail) // objects refilled by interrupt?
2081 goto retry;
2082 }
2083 ac->touched = 1;
2084 return ac_entry(ac)[--ac->avail];
2085}
2086
2087static inline void
2088cache_alloc_debugcheck_before(kmem_cache_t *cachep, unsigned int __nocast flags)
2089{
2090 might_sleep_if(flags & __GFP_WAIT);
2091#if DEBUG
2092 kmem_flagcheck(cachep, flags);
2093#endif
2094}
2095
2096#if DEBUG
2097static void *
2098cache_alloc_debugcheck_after(kmem_cache_t *cachep,
2099 unsigned long flags, void *objp, void *caller)
2100{
2101 if (!objp)
2102 return objp;
2103 if (cachep->flags & SLAB_POISON) {
2104#ifdef CONFIG_DEBUG_PAGEALLOC
2105 if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
2106 kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 1);
2107 else
2108 check_poison_obj(cachep, objp);
2109#else
2110 check_poison_obj(cachep, objp);
2111#endif
2112 poison_obj(cachep, objp, POISON_INUSE);
2113 }
2114 if (cachep->flags & SLAB_STORE_USER)
2115 *dbg_userword(cachep, objp) = caller;
2116
2117 if (cachep->flags & SLAB_RED_ZONE) {
2118 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
2119 slab_error(cachep, "double free, or memory outside"
2120 " object was overwritten");
2121 printk(KERN_ERR "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n",
2122 objp, *dbg_redzone1(cachep, objp), *dbg_redzone2(cachep, objp));
2123 }
2124 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
2125 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
2126 }
2127 objp += obj_dbghead(cachep);
2128 if (cachep->ctor && cachep->flags & SLAB_POISON) {
2129 unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR;
2130
2131 if (!(flags & __GFP_WAIT))
2132 ctor_flags |= SLAB_CTOR_ATOMIC;
2133
2134 cachep->ctor(objp, cachep, ctor_flags);
2135 }
2136 return objp;
2137}
2138#else
2139#define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
2140#endif
2141
2142
2143static inline void *__cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags)
2144{
2145 unsigned long save_flags;
2146 void* objp;
2147 struct array_cache *ac;
2148
2149 cache_alloc_debugcheck_before(cachep, flags);
2150
2151 local_irq_save(save_flags);
2152 ac = ac_data(cachep);
2153 if (likely(ac->avail)) {
2154 STATS_INC_ALLOCHIT(cachep);
2155 ac->touched = 1;
2156 objp = ac_entry(ac)[--ac->avail];
2157 } else {
2158 STATS_INC_ALLOCMISS(cachep);
2159 objp = cache_alloc_refill(cachep, flags);
2160 }
2161 local_irq_restore(save_flags);
2162 objp = cache_alloc_debugcheck_after(cachep, flags, objp, __builtin_return_address(0));
2163 return objp;
2164}
2165
2166/*
2167 * NUMA: different approach needed if the spinlock is moved into
2168 * the l3 structure
2169 */
2170
2171static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects)
2172{
2173 int i;
2174
2175 check_spinlock_acquired(cachep);
2176
2177 /* NUMA: move add into loop */
2178 cachep->lists.free_objects += nr_objects;
2179
2180 for (i = 0; i < nr_objects; i++) {
2181 void *objp = objpp[i];
2182 struct slab *slabp;
2183 unsigned int objnr;
2184
2185 slabp = GET_PAGE_SLAB(virt_to_page(objp));
2186 list_del(&slabp->list);
2187 objnr = (objp - slabp->s_mem) / cachep->objsize;
2188 check_slabp(cachep, slabp);
2189#if DEBUG
2190 if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) {
2191 printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n",
2192 cachep->name, objp);
2193 BUG();
2194 }
2195#endif
2196 slab_bufctl(slabp)[objnr] = slabp->free;
2197 slabp->free = objnr;
2198 STATS_DEC_ACTIVE(cachep);
2199 slabp->inuse--;
2200 check_slabp(cachep, slabp);
2201
2202 /* fixup slab chains */
2203 if (slabp->inuse == 0) {
2204 if (cachep->lists.free_objects > cachep->free_limit) {
2205 cachep->lists.free_objects -= cachep->num;
2206 slab_destroy(cachep, slabp);
2207 } else {
2208 list_add(&slabp->list,
2209 &list3_data_ptr(cachep, objp)->slabs_free);
2210 }
2211 } else {
2212 /* Unconditionally move a slab to the end of the
2213 * partial list on free - maximum time for the
2214 * other objects to be freed, too.
2215 */
2216 list_add_tail(&slabp->list,
2217 &list3_data_ptr(cachep, objp)->slabs_partial);
2218 }
2219 }
2220}
2221
2222static void cache_flusharray(kmem_cache_t *cachep, struct array_cache *ac)
2223{
2224 int batchcount;
2225
2226 batchcount = ac->batchcount;
2227#if DEBUG
2228 BUG_ON(!batchcount || batchcount > ac->avail);
2229#endif
2230 check_irq_off();
2231 spin_lock(&cachep->spinlock);
2232 if (cachep->lists.shared) {
2233 struct array_cache *shared_array = cachep->lists.shared;
2234 int max = shared_array->limit-shared_array->avail;
2235 if (max) {
2236 if (batchcount > max)
2237 batchcount = max;
2238 memcpy(&ac_entry(shared_array)[shared_array->avail],
2239 &ac_entry(ac)[0],
2240 sizeof(void*)*batchcount);
2241 shared_array->avail += batchcount;
2242 goto free_done;
2243 }
2244 }
2245
2246 free_block(cachep, &ac_entry(ac)[0], batchcount);
2247free_done:
2248#if STATS
2249 {
2250 int i = 0;
2251 struct list_head *p;
2252
2253 p = list3_data(cachep)->slabs_free.next;
2254 while (p != &(list3_data(cachep)->slabs_free)) {
2255 struct slab *slabp;
2256
2257 slabp = list_entry(p, struct slab, list);
2258 BUG_ON(slabp->inuse);
2259
2260 i++;
2261 p = p->next;
2262 }
2263 STATS_SET_FREEABLE(cachep, i);
2264 }
2265#endif
2266 spin_unlock(&cachep->spinlock);
2267 ac->avail -= batchcount;
2268 memmove(&ac_entry(ac)[0], &ac_entry(ac)[batchcount],
2269 sizeof(void*)*ac->avail);
2270}
2271
2272/*
2273 * __cache_free
2274 * Release an obj back to its cache. If the obj has a constructed
2275 * state, it must be in this state _before_ it is released.
2276 *
2277 * Called with disabled ints.
2278 */
2279static inline void __cache_free(kmem_cache_t *cachep, void *objp)
2280{
2281 struct array_cache *ac = ac_data(cachep);
2282
2283 check_irq_off();
2284 objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
2285
2286 if (likely(ac->avail < ac->limit)) {
2287 STATS_INC_FREEHIT(cachep);
2288 ac_entry(ac)[ac->avail++] = objp;
2289 return;
2290 } else {
2291 STATS_INC_FREEMISS(cachep);
2292 cache_flusharray(cachep, ac);
2293 ac_entry(ac)[ac->avail++] = objp;
2294 }
2295}
2296
2297/**
2298 * kmem_cache_alloc - Allocate an object
2299 * @cachep: The cache to allocate from.
2300 * @flags: See kmalloc().
2301 *
2302 * Allocate an object from this cache. The flags are only relevant
2303 * if the cache has no available objects.
2304 */
2305void *kmem_cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags)
2306{
2307 return __cache_alloc(cachep, flags);
2308}
2309EXPORT_SYMBOL(kmem_cache_alloc);
2310
2311/**
2312 * kmem_ptr_validate - check if an untrusted pointer might
2313 * be a slab entry.
2314 * @cachep: the cache we're checking against
2315 * @ptr: pointer to validate
2316 *
2317 * This verifies that the untrusted pointer looks sane:
2318 * it is _not_ a guarantee that the pointer is actually
2319 * part of the slab cache in question, but it at least
2320 * validates that the pointer can be dereferenced and
2321 * looks half-way sane.
2322 *
2323 * Currently only used for dentry validation.
2324 */
2325int fastcall kmem_ptr_validate(kmem_cache_t *cachep, void *ptr)
2326{
2327 unsigned long addr = (unsigned long) ptr;
2328 unsigned long min_addr = PAGE_OFFSET;
2329 unsigned long align_mask = BYTES_PER_WORD-1;
2330 unsigned long size = cachep->objsize;
2331 struct page *page;
2332
2333 if (unlikely(addr < min_addr))
2334 goto out;
2335 if (unlikely(addr > (unsigned long)high_memory - size))
2336 goto out;
2337 if (unlikely(addr & align_mask))
2338 goto out;
2339 if (unlikely(!kern_addr_valid(addr)))
2340 goto out;
2341 if (unlikely(!kern_addr_valid(addr + size - 1)))
2342 goto out;
2343 page = virt_to_page(ptr);
2344 if (unlikely(!PageSlab(page)))
2345 goto out;
2346 if (unlikely(GET_PAGE_CACHE(page) != cachep))
2347 goto out;
2348 return 1;
2349out:
2350 return 0;
2351}
2352
2353#ifdef CONFIG_NUMA
2354/**
2355 * kmem_cache_alloc_node - Allocate an object on the specified node
2356 * @cachep: The cache to allocate from.
2357 * @flags: See kmalloc().
2358 * @nodeid: node number of the target node.
2359 *
2360 * Identical to kmem_cache_alloc, except that this function is slow
2361 * and can sleep. And it will allocate memory on the given node, which
2362 * can improve the performance for cpu bound structures.
2363 */
2364void *kmem_cache_alloc_node(kmem_cache_t *cachep, int nodeid)
2365{
2366 int loop;
2367 void *objp;
2368 struct slab *slabp;
2369 kmem_bufctl_t next;
2370
2371 for (loop = 0;;loop++) {
2372 struct list_head *q;
2373
2374 objp = NULL;
2375 check_irq_on();
2376 spin_lock_irq(&cachep->spinlock);
2377 /* walk through all partial and empty slab and find one
2378 * from the right node */
2379 list_for_each(q,&cachep->lists.slabs_partial) {
2380 slabp = list_entry(q, struct slab, list);
2381
2382 if (page_to_nid(virt_to_page(slabp->s_mem)) == nodeid ||
2383 loop > 2)
2384 goto got_slabp;
2385 }
2386 list_for_each(q, &cachep->lists.slabs_free) {
2387 slabp = list_entry(q, struct slab, list);
2388
2389 if (page_to_nid(virt_to_page(slabp->s_mem)) == nodeid ||
2390 loop > 2)
2391 goto got_slabp;
2392 }
2393 spin_unlock_irq(&cachep->spinlock);
2394
2395 local_irq_disable();
2396 if (!cache_grow(cachep, GFP_KERNEL, nodeid)) {
2397 local_irq_enable();
2398 return NULL;
2399 }
2400 local_irq_enable();
2401 }
2402got_slabp:
2403 /* found one: allocate object */
2404 check_slabp(cachep, slabp);
2405 check_spinlock_acquired(cachep);
2406
2407 STATS_INC_ALLOCED(cachep);
2408 STATS_INC_ACTIVE(cachep);
2409 STATS_SET_HIGH(cachep);
2410 STATS_INC_NODEALLOCS(cachep);
2411
2412 objp = slabp->s_mem + slabp->free*cachep->objsize;
2413
2414 slabp->inuse++;
2415 next = slab_bufctl(slabp)[slabp->free];
2416#if DEBUG
2417 slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
2418#endif
2419 slabp->free = next;
2420 check_slabp(cachep, slabp);
2421
2422 /* move slabp to correct slabp list: */
2423 list_del(&slabp->list);
2424 if (slabp->free == BUFCTL_END)
2425 list_add(&slabp->list, &cachep->lists.slabs_full);
2426 else
2427 list_add(&slabp->list, &cachep->lists.slabs_partial);
2428
2429 list3_data(cachep)->free_objects--;
2430 spin_unlock_irq(&cachep->spinlock);
2431
2432 objp = cache_alloc_debugcheck_after(cachep, GFP_KERNEL, objp,
2433 __builtin_return_address(0));
2434 return objp;
2435}
2436EXPORT_SYMBOL(kmem_cache_alloc_node);
2437
2438#endif
2439
2440/**
2441 * kmalloc - allocate memory
2442 * @size: how many bytes of memory are required.
2443 * @flags: the type of memory to allocate.
2444 *
2445 * kmalloc is the normal method of allocating memory
2446 * in the kernel.
2447 *
2448 * The @flags argument may be one of:
2449 *
2450 * %GFP_USER - Allocate memory on behalf of user. May sleep.
2451 *
2452 * %GFP_KERNEL - Allocate normal kernel ram. May sleep.
2453 *
2454 * %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers.
2455 *
2456 * Additionally, the %GFP_DMA flag may be set to indicate the memory
2457 * must be suitable for DMA. This can mean different things on different
2458 * platforms. For example, on i386, it means that the memory must come
2459 * from the first 16MB.
2460 */
2461void *__kmalloc(size_t size, unsigned int __nocast flags)
2462{
2463 kmem_cache_t *cachep;
2464
2465 cachep = kmem_find_general_cachep(size, flags);
2466 if (unlikely(cachep == NULL))
2467 return NULL;
2468 return __cache_alloc(cachep, flags);
2469}
2470EXPORT_SYMBOL(__kmalloc);
2471
2472#ifdef CONFIG_SMP
2473/**
2474 * __alloc_percpu - allocate one copy of the object for every present
2475 * cpu in the system, zeroing them.
2476 * Objects should be dereferenced using the per_cpu_ptr macro only.
2477 *
2478 * @size: how many bytes of memory are required.
2479 * @align: the alignment, which can't be greater than SMP_CACHE_BYTES.
2480 */
2481void *__alloc_percpu(size_t size, size_t align)
2482{
2483 int i;
2484 struct percpu_data *pdata = kmalloc(sizeof (*pdata), GFP_KERNEL);
2485
2486 if (!pdata)
2487 return NULL;
2488
2489 for (i = 0; i < NR_CPUS; i++) {
2490 if (!cpu_possible(i))
2491 continue;
2492 pdata->ptrs[i] = kmem_cache_alloc_node(
2493 kmem_find_general_cachep(size, GFP_KERNEL),
2494 cpu_to_node(i));
2495
2496 if (!pdata->ptrs[i])
2497 goto unwind_oom;
2498 memset(pdata->ptrs[i], 0, size);
2499 }
2500
2501 /* Catch derefs w/o wrappers */
2502 return (void *) (~(unsigned long) pdata);
2503
2504unwind_oom:
2505 while (--i >= 0) {
2506 if (!cpu_possible(i))
2507 continue;
2508 kfree(pdata->ptrs[i]);
2509 }
2510 kfree(pdata);
2511 return NULL;
2512}
2513EXPORT_SYMBOL(__alloc_percpu);
2514#endif
2515
2516/**
2517 * kmem_cache_free - Deallocate an object
2518 * @cachep: The cache the allocation was from.
2519 * @objp: The previously allocated object.
2520 *
2521 * Free an object which was previously allocated from this
2522 * cache.
2523 */
2524void kmem_cache_free(kmem_cache_t *cachep, void *objp)
2525{
2526 unsigned long flags;
2527
2528 local_irq_save(flags);
2529 __cache_free(cachep, objp);
2530 local_irq_restore(flags);
2531}
2532EXPORT_SYMBOL(kmem_cache_free);
2533
2534/**
2535 * kcalloc - allocate memory for an array. The memory is set to zero.
2536 * @n: number of elements.
2537 * @size: element size.
2538 * @flags: the type of memory to allocate.
2539 */
2540void *kcalloc(size_t n, size_t size, unsigned int __nocast flags)
2541{
2542 void *ret = NULL;
2543
2544 if (n != 0 && size > INT_MAX / n)
2545 return ret;
2546
2547 ret = kmalloc(n * size, flags);
2548 if (ret)
2549 memset(ret, 0, n * size);
2550 return ret;
2551}
2552EXPORT_SYMBOL(kcalloc);
2553
2554/**
2555 * kfree - free previously allocated memory
2556 * @objp: pointer returned by kmalloc.
2557 *
2558 * Don't free memory not originally allocated by kmalloc()
2559 * or you will run into trouble.
2560 */
2561void kfree(const void *objp)
2562{
2563 kmem_cache_t *c;
2564 unsigned long flags;
2565
2566 if (unlikely(!objp))
2567 return;
2568 local_irq_save(flags);
2569 kfree_debugcheck(objp);
2570 c = GET_PAGE_CACHE(virt_to_page(objp));
2571 __cache_free(c, (void*)objp);
2572 local_irq_restore(flags);
2573}
2574EXPORT_SYMBOL(kfree);
2575
2576#ifdef CONFIG_SMP
2577/**
2578 * free_percpu - free previously allocated percpu memory
2579 * @objp: pointer returned by alloc_percpu.
2580 *
2581 * Don't free memory not originally allocated by alloc_percpu()
2582 * The complemented objp is to check for that.
2583 */
2584void
2585free_percpu(const void *objp)
2586{
2587 int i;
2588 struct percpu_data *p = (struct percpu_data *) (~(unsigned long) objp);
2589
2590 for (i = 0; i < NR_CPUS; i++) {
2591 if (!cpu_possible(i))
2592 continue;
2593 kfree(p->ptrs[i]);
2594 }
2595 kfree(p);
2596}
2597EXPORT_SYMBOL(free_percpu);
2598#endif
2599
2600unsigned int kmem_cache_size(kmem_cache_t *cachep)
2601{
2602 return obj_reallen(cachep);
2603}
2604EXPORT_SYMBOL(kmem_cache_size);
2605
2606struct ccupdate_struct {
2607 kmem_cache_t *cachep;
2608 struct array_cache *new[NR_CPUS];
2609};
2610
2611static void do_ccupdate_local(void *info)
2612{
2613 struct ccupdate_struct *new = (struct ccupdate_struct *)info;
2614 struct array_cache *old;
2615
2616 check_irq_off();
2617 old = ac_data(new->cachep);
2618
2619 new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()];
2620 new->new[smp_processor_id()] = old;
2621}
2622
2623
2624static int do_tune_cpucache(kmem_cache_t *cachep, int limit, int batchcount,
2625 int shared)
2626{
2627 struct ccupdate_struct new;
2628 struct array_cache *new_shared;
2629 int i;
2630
2631 memset(&new.new,0,sizeof(new.new));
2632 for (i = 0; i < NR_CPUS; i++) {
2633 if (cpu_online(i)) {
2634 new.new[i] = alloc_arraycache(i, limit, batchcount);
2635 if (!new.new[i]) {
2636 for (i--; i >= 0; i--) kfree(new.new[i]);
2637 return -ENOMEM;
2638 }
2639 } else {
2640 new.new[i] = NULL;
2641 }
2642 }
2643 new.cachep = cachep;
2644
2645 smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
2646
2647 check_irq_on();
2648 spin_lock_irq(&cachep->spinlock);
2649 cachep->batchcount = batchcount;
2650 cachep->limit = limit;
2651 cachep->free_limit = (1+num_online_cpus())*cachep->batchcount + cachep->num;
2652 spin_unlock_irq(&cachep->spinlock);
2653
2654 for (i = 0; i < NR_CPUS; i++) {
2655 struct array_cache *ccold = new.new[i];
2656 if (!ccold)
2657 continue;
2658 spin_lock_irq(&cachep->spinlock);
2659 free_block(cachep, ac_entry(ccold), ccold->avail);
2660 spin_unlock_irq(&cachep->spinlock);
2661 kfree(ccold);
2662 }
2663 new_shared = alloc_arraycache(-1, batchcount*shared, 0xbaadf00d);
2664 if (new_shared) {
2665 struct array_cache *old;
2666
2667 spin_lock_irq(&cachep->spinlock);
2668 old = cachep->lists.shared;
2669 cachep->lists.shared = new_shared;
2670 if (old)
2671 free_block(cachep, ac_entry(old), old->avail);
2672 spin_unlock_irq(&cachep->spinlock);
2673 kfree(old);
2674 }
2675
2676 return 0;
2677}
2678
2679
2680static void enable_cpucache(kmem_cache_t *cachep)
2681{
2682 int err;
2683 int limit, shared;
2684
2685 /* The head array serves three purposes:
2686 * - create a LIFO ordering, i.e. return objects that are cache-warm
2687 * - reduce the number of spinlock operations.
2688 * - reduce the number of linked list operations on the slab and
2689 * bufctl chains: array operations are cheaper.
2690 * The numbers are guessed, we should auto-tune as described by
2691 * Bonwick.
2692 */
2693 if (cachep->objsize > 131072)
2694 limit = 1;
2695 else if (cachep->objsize > PAGE_SIZE)
2696 limit = 8;
2697 else if (cachep->objsize > 1024)
2698 limit = 24;
2699 else if (cachep->objsize > 256)
2700 limit = 54;
2701 else
2702 limit = 120;
2703
2704 /* Cpu bound tasks (e.g. network routing) can exhibit cpu bound
2705 * allocation behaviour: Most allocs on one cpu, most free operations
2706 * on another cpu. For these cases, an efficient object passing between
2707 * cpus is necessary. This is provided by a shared array. The array
2708 * replaces Bonwick's magazine layer.
2709 * On uniprocessor, it's functionally equivalent (but less efficient)
2710 * to a larger limit. Thus disabled by default.
2711 */
2712 shared = 0;
2713#ifdef CONFIG_SMP
2714 if (cachep->objsize <= PAGE_SIZE)
2715 shared = 8;
2716#endif
2717
2718#if DEBUG
2719 /* With debugging enabled, large batchcount lead to excessively
2720 * long periods with disabled local interrupts. Limit the
2721 * batchcount
2722 */
2723 if (limit > 32)
2724 limit = 32;
2725#endif
2726 err = do_tune_cpucache(cachep, limit, (limit+1)/2, shared);
2727 if (err)
2728 printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
2729 cachep->name, -err);
2730}
2731
2732static void drain_array_locked(kmem_cache_t *cachep,
2733 struct array_cache *ac, int force)
2734{
2735 int tofree;
2736
2737 check_spinlock_acquired(cachep);
2738 if (ac->touched && !force) {
2739 ac->touched = 0;
2740 } else if (ac->avail) {
2741 tofree = force ? ac->avail : (ac->limit+4)/5;
2742 if (tofree > ac->avail) {
2743 tofree = (ac->avail+1)/2;
2744 }
2745 free_block(cachep, ac_entry(ac), tofree);
2746 ac->avail -= tofree;
2747 memmove(&ac_entry(ac)[0], &ac_entry(ac)[tofree],
2748 sizeof(void*)*ac->avail);
2749 }
2750}
2751
2752/**
2753 * cache_reap - Reclaim memory from caches.
2754 *
2755 * Called from workqueue/eventd every few seconds.
2756 * Purpose:
2757 * - clear the per-cpu caches for this CPU.
2758 * - return freeable pages to the main free memory pool.
2759 *
2760 * If we cannot acquire the cache chain semaphore then just give up - we'll
2761 * try again on the next iteration.
2762 */
2763static void cache_reap(void *unused)
2764{
2765 struct list_head *walk;
2766
2767 if (down_trylock(&cache_chain_sem)) {
2768 /* Give up. Setup the next iteration. */
2769 schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC + smp_processor_id());
2770 return;
2771 }
2772
2773 list_for_each(walk, &cache_chain) {
2774 kmem_cache_t *searchp;
2775 struct list_head* p;
2776 int tofree;
2777 struct slab *slabp;
2778
2779 searchp = list_entry(walk, kmem_cache_t, next);
2780
2781 if (searchp->flags & SLAB_NO_REAP)
2782 goto next;
2783
2784 check_irq_on();
2785
2786 spin_lock_irq(&searchp->spinlock);
2787
2788 drain_array_locked(searchp, ac_data(searchp), 0);
2789
2790 if(time_after(searchp->lists.next_reap, jiffies))
2791 goto next_unlock;
2792
2793 searchp->lists.next_reap = jiffies + REAPTIMEOUT_LIST3;
2794
2795 if (searchp->lists.shared)
2796 drain_array_locked(searchp, searchp->lists.shared, 0);
2797
2798 if (searchp->lists.free_touched) {
2799 searchp->lists.free_touched = 0;
2800 goto next_unlock;
2801 }
2802
2803 tofree = (searchp->free_limit+5*searchp->num-1)/(5*searchp->num);
2804 do {
2805 p = list3_data(searchp)->slabs_free.next;
2806 if (p == &(list3_data(searchp)->slabs_free))
2807 break;
2808
2809 slabp = list_entry(p, struct slab, list);
2810 BUG_ON(slabp->inuse);
2811 list_del(&slabp->list);
2812 STATS_INC_REAPED(searchp);
2813
2814 /* Safe to drop the lock. The slab is no longer
2815 * linked to the cache.
2816 * searchp cannot disappear, we hold
2817 * cache_chain_lock
2818 */
2819 searchp->lists.free_objects -= searchp->num;
2820 spin_unlock_irq(&searchp->spinlock);
2821 slab_destroy(searchp, slabp);
2822 spin_lock_irq(&searchp->spinlock);
2823 } while(--tofree > 0);
2824next_unlock:
2825 spin_unlock_irq(&searchp->spinlock);
2826next:
2827 cond_resched();
2828 }
2829 check_irq_on();
2830 up(&cache_chain_sem);
2831 /* Setup the next iteration */
2832 schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC + smp_processor_id());
2833}
2834
2835#ifdef CONFIG_PROC_FS
2836
2837static void *s_start(struct seq_file *m, loff_t *pos)
2838{
2839 loff_t n = *pos;
2840 struct list_head *p;
2841
2842 down(&cache_chain_sem);
2843 if (!n) {
2844 /*
2845 * Output format version, so at least we can change it
2846 * without _too_ many complaints.
2847 */
2848#if STATS
2849 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n");
2850#else
2851 seq_puts(m, "slabinfo - version: 2.1\n");
2852#endif
2853 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>");
2854 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
2855 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
2856#if STATS
2857 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped>"
2858 " <error> <maxfreeable> <freelimit> <nodeallocs>");
2859 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>");
2860#endif
2861 seq_putc(m, '\n');
2862 }
2863 p = cache_chain.next;
2864 while (n--) {
2865 p = p->next;
2866 if (p == &cache_chain)
2867 return NULL;
2868 }
2869 return list_entry(p, kmem_cache_t, next);
2870}
2871
2872static void *s_next(struct seq_file *m, void *p, loff_t *pos)
2873{
2874 kmem_cache_t *cachep = p;
2875 ++*pos;
2876 return cachep->next.next == &cache_chain ? NULL
2877 : list_entry(cachep->next.next, kmem_cache_t, next);
2878}
2879
2880static void s_stop(struct seq_file *m, void *p)
2881{
2882 up(&cache_chain_sem);
2883}
2884
2885static int s_show(struct seq_file *m, void *p)
2886{
2887 kmem_cache_t *cachep = p;
2888 struct list_head *q;
2889 struct slab *slabp;
2890 unsigned long active_objs;
2891 unsigned long num_objs;
2892 unsigned long active_slabs = 0;
2893 unsigned long num_slabs;
2894 const char *name;
2895 char *error = NULL;
2896
2897 check_irq_on();
2898 spin_lock_irq(&cachep->spinlock);
2899 active_objs = 0;
2900 num_slabs = 0;
2901 list_for_each(q,&cachep->lists.slabs_full) {
2902 slabp = list_entry(q, struct slab, list);
2903 if (slabp->inuse != cachep->num && !error)
2904 error = "slabs_full accounting error";
2905 active_objs += cachep->num;
2906 active_slabs++;
2907 }
2908 list_for_each(q,&cachep->lists.slabs_partial) {
2909 slabp = list_entry(q, struct slab, list);
2910 if (slabp->inuse == cachep->num && !error)
2911 error = "slabs_partial inuse accounting error";
2912 if (!slabp->inuse && !error)
2913 error = "slabs_partial/inuse accounting error";
2914 active_objs += slabp->inuse;
2915 active_slabs++;
2916 }
2917 list_for_each(q,&cachep->lists.slabs_free) {
2918 slabp = list_entry(q, struct slab, list);
2919 if (slabp->inuse && !error)
2920 error = "slabs_free/inuse accounting error";
2921 num_slabs++;
2922 }
2923 num_slabs+=active_slabs;
2924 num_objs = num_slabs*cachep->num;
2925 if (num_objs - active_objs != cachep->lists.free_objects && !error)
2926 error = "free_objects accounting error";
2927
2928 name = cachep->name;
2929 if (error)
2930 printk(KERN_ERR "slab: cache %s error: %s\n", name, error);
2931
2932 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d",
2933 name, active_objs, num_objs, cachep->objsize,
2934 cachep->num, (1<<cachep->gfporder));
2935 seq_printf(m, " : tunables %4u %4u %4u",
2936 cachep->limit, cachep->batchcount,
2937 cachep->lists.shared->limit/cachep->batchcount);
2938 seq_printf(m, " : slabdata %6lu %6lu %6u",
2939 active_slabs, num_slabs, cachep->lists.shared->avail);
2940#if STATS
2941 { /* list3 stats */
2942 unsigned long high = cachep->high_mark;
2943 unsigned long allocs = cachep->num_allocations;
2944 unsigned long grown = cachep->grown;
2945 unsigned long reaped = cachep->reaped;
2946 unsigned long errors = cachep->errors;
2947 unsigned long max_freeable = cachep->max_freeable;
2948 unsigned long free_limit = cachep->free_limit;
2949 unsigned long node_allocs = cachep->node_allocs;
2950
2951 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu",
2952 allocs, high, grown, reaped, errors,
2953 max_freeable, free_limit, node_allocs);
2954 }
2955 /* cpu stats */
2956 {
2957 unsigned long allochit = atomic_read(&cachep->allochit);
2958 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
2959 unsigned long freehit = atomic_read(&cachep->freehit);
2960 unsigned long freemiss = atomic_read(&cachep->freemiss);
2961
2962 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
2963 allochit, allocmiss, freehit, freemiss);
2964 }
2965#endif
2966 seq_putc(m, '\n');
2967 spin_unlock_irq(&cachep->spinlock);
2968 return 0;
2969}
2970
2971/*
2972 * slabinfo_op - iterator that generates /proc/slabinfo
2973 *
2974 * Output layout:
2975 * cache-name
2976 * num-active-objs
2977 * total-objs
2978 * object size
2979 * num-active-slabs
2980 * total-slabs
2981 * num-pages-per-slab
2982 * + further values on SMP and with statistics enabled
2983 */
2984
2985struct seq_operations slabinfo_op = {
2986 .start = s_start,
2987 .next = s_next,
2988 .stop = s_stop,
2989 .show = s_show,
2990};
2991
2992#define MAX_SLABINFO_WRITE 128
2993/**
2994 * slabinfo_write - Tuning for the slab allocator
2995 * @file: unused
2996 * @buffer: user buffer
2997 * @count: data length
2998 * @ppos: unused
2999 */
3000ssize_t slabinfo_write(struct file *file, const char __user *buffer,
3001 size_t count, loff_t *ppos)
3002{
3003 char kbuf[MAX_SLABINFO_WRITE+1], *tmp;
3004 int limit, batchcount, shared, res;
3005 struct list_head *p;
3006
3007 if (count > MAX_SLABINFO_WRITE)
3008 return -EINVAL;
3009 if (copy_from_user(&kbuf, buffer, count))
3010 return -EFAULT;
3011 kbuf[MAX_SLABINFO_WRITE] = '\0';
3012
3013 tmp = strchr(kbuf, ' ');
3014 if (!tmp)
3015 return -EINVAL;
3016 *tmp = '\0';
3017 tmp++;
3018 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
3019 return -EINVAL;
3020
3021 /* Find the cache in the chain of caches. */
3022 down(&cache_chain_sem);
3023 res = -EINVAL;
3024 list_for_each(p,&cache_chain) {
3025 kmem_cache_t *cachep = list_entry(p, kmem_cache_t, next);
3026
3027 if (!strcmp(cachep->name, kbuf)) {
3028 if (limit < 1 ||
3029 batchcount < 1 ||
3030 batchcount > limit ||
3031 shared < 0) {
3032 res = -EINVAL;
3033 } else {
3034 res = do_tune_cpucache(cachep, limit, batchcount, shared);
3035 }
3036 break;
3037 }
3038 }
3039 up(&cache_chain_sem);
3040 if (res >= 0)
3041 res = count;
3042 return res;
3043}
3044#endif
3045
3046unsigned int ksize(const void *objp)
3047{
3048 kmem_cache_t *c;
3049 unsigned long flags;
3050 unsigned int size = 0;
3051
3052 if (likely(objp != NULL)) {
3053 local_irq_save(flags);
3054 c = GET_PAGE_CACHE(virt_to_page(objp));
3055 size = kmem_cache_size(c);
3056 local_irq_restore(flags);
3057 }
3058
3059 return size;
3060}
generated by cgit v1.2.2 (git 2.25.0) at 2024-11-01 04:16:15 -0400