]>
Commit | Line | Data |
---|---|---|
1da177e4 LT |
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 | */ | |
198 | static 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 | */ | |
207 | struct 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 | */ | |
231 | struct 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 | */ | |
250 | struct 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 | |
261 | struct 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 | */ | |
273 | struct 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 | ||
302 | struct 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 | */ | |
435 | static int obj_dbghead(kmem_cache_t *cachep) | |
436 | { | |
437 | return cachep->dbghead; | |
438 | } | |
439 | ||
440 | static int obj_reallen(kmem_cache_t *cachep) | |
441 | { | |
442 | return cachep->reallen; | |
443 | } | |
444 | ||
445 | static 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 | ||
451 | static 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 | ||
459 | static 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 | |
495 | static 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. */ | |
507 | struct 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 | }; | |
513 | EXPORT_SYMBOL(malloc_sizes); | |
514 | ||
515 | /* Must match cache_sizes above. Out of line to keep cache footprint low. */ | |
516 | struct cache_names { | |
517 | char *name; | |
518 | char *name_dma; | |
519 | }; | |
520 | ||
521 | static 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 | ||
528 | static struct arraycache_init initarray_cache __initdata = | |
529 | { { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; | |
530 | static struct arraycache_init initarray_generic = | |
531 | { { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; | |
532 | ||
533 | /* internal cache of cache description objs */ | |
534 | static 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. */ | |
548 | static struct semaphore cache_chain_sem; | |
549 | static 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 | */ | |
557 | atomic_t slab_reclaim_pages; | |
558 | EXPORT_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 | */ | |
564 | static enum { | |
565 | NONE, | |
566 | PARTIAL, | |
567 | FULL | |
568 | } g_cpucache_up; | |
569 | ||
570 | static DEFINE_PER_CPU(struct work_struct, reap_work); | |
571 | ||
572 | static void free_block(kmem_cache_t* cachep, void** objpp, int len); | |
573 | static void enable_cpucache (kmem_cache_t *cachep); | |
574 | static void cache_reap (void *unused); | |
575 | ||
576 | static inline void **ac_entry(struct array_cache *ac) | |
577 | { | |
578 | return (void**)(ac+1); | |
579 | } | |
580 | ||
581 | static inline struct array_cache *ac_data(kmem_cache_t *cachep) | |
582 | { | |
583 | return cachep->array[smp_processor_id()]; | |
584 | } | |
585 | ||
586 | static 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. */ | |
611 | static 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 | ||
640 | static 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 | */ | |
654 | static 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 | ||
669 | static 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 | ||
692 | static 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; | |
743 | bad: | |
744 | up(&cache_chain_sem); | |
745 | return NOTIFY_BAD; | |
746 | } | |
747 | ||
748 | static 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 | */ | |
753 | void __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 | ||
873 | static 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 | */ | |
898 | static 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 | */ | |
928 | static 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 | ||
947 | static 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 | |
960 | static 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 | ||
993 | static 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 | ||
1002 | static 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 | ||
1015 | static 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 | ||
1044 | static 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 | */ | |
1109 | static 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 | */ | |
1196 | kmem_cache_t * | |
1197 | kmem_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; | |
1352 | cal_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. */ | |
1378 | next: | |
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(); | |
1492 | opps: | |
1493 | if (!cachep && (flags & SLAB_PANIC)) | |
1494 | panic("kmem_cache_create(): failed to create slab `%s'\n", | |
1495 | name); | |
1496 | return cachep; | |
1497 | } | |
1498 | EXPORT_SYMBOL(kmem_cache_create); | |
1499 | ||
1500 | #if DEBUG | |
1501 | static void check_irq_off(void) | |
1502 | { | |
1503 | BUG_ON(!irqs_disabled()); | |
1504 | } | |
1505 | ||
1506 | static void check_irq_on(void) | |
1507 | { | |
1508 | BUG_ON(irqs_disabled()); | |
1509 | } | |
1510 | ||
1511 | static 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 | */ | |
1527 | static 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 | ||
1542 | static void drain_array_locked(kmem_cache_t* cachep, | |
1543 | struct array_cache *ac, int force); | |
1544 | ||
1545 | static 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 | ||
1558 | static 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 */ | |
1570 | static 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 | */ | |
1612 | int kmem_cache_shrink(kmem_cache_t *cachep) | |
1613 | { | |
1614 | if (!cachep || in_interrupt()) | |
1615 | BUG(); | |
1616 | ||
1617 | return __cache_shrink(cachep); | |
1618 | } | |
1619 | EXPORT_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 | */ | |
1638 | int 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 | } | |
1683 | EXPORT_SYMBOL(kmem_cache_destroy); | |
1684 | ||
1685 | /* Get the memory for a slab management obj. */ | |
1686 | static 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 | ||
1707 | static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp) | |
1708 | { | |
1709 | return (kmem_bufctl_t *)(slabp+1); | |
1710 | } | |
1711 | ||
1712 | static 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 | ||
1758 | static 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 | ||
1769 | static 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 | */ | |
1788 | static 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; | |
1861 | opps1: | |
1862 | kmem_freepages(cachep, objp); | |
1863 | failed: | |
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 | */ | |
1877 | static 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 | ||
1893 | static 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 | ||
1960 | static 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) { | |
1973 | bad: | |
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 | ||
1991 | static 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); | |
1999 | retry: | |
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 | ||
2066 | must_grow: | |
2067 | l3->free_objects -= ac->avail; | |
2068 | alloc_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 | ||
2087 | static inline void | |
2088 | cache_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 | |
2097 | static void * | |
2098 | cache_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 | ||
2143 | static 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 | ||
2171 | static 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 | ||
2222 | static 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); | |
2247 | free_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 | */ | |
2279 | static 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 | */ | |
2305 | void *kmem_cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) | |
2306 | { | |
2307 | return __cache_alloc(cachep, flags); | |
2308 | } | |
2309 | EXPORT_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 | */ | |
2325 | int 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; | |
2349 | out: | |
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 | */ | |
2364 | void *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 | } | |
2402 | got_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 | } | |
2436 | EXPORT_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 | */ | |
2461 | void *__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 | } | |
2470 | EXPORT_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 | */ | |
2481 | void *__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 | ||
2504 | unwind_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 | } | |
2513 | EXPORT_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 | */ | |
2524 | void 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 | } | |
2532 | EXPORT_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 | */ | |
2540 | void *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 | } | |
2552 | EXPORT_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 | */ | |
2561 | void 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 | } | |
2574 | EXPORT_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 | */ | |
2584 | void | |
2585 | free_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 | } | |
2597 | EXPORT_SYMBOL(free_percpu); | |
2598 | #endif | |
2599 | ||
2600 | unsigned int kmem_cache_size(kmem_cache_t *cachep) | |
2601 | { | |
2602 | return obj_reallen(cachep); | |
2603 | } | |
2604 | EXPORT_SYMBOL(kmem_cache_size); | |
2605 | ||
2606 | struct ccupdate_struct { | |
2607 | kmem_cache_t *cachep; | |
2608 | struct array_cache *new[NR_CPUS]; | |
2609 | }; | |
2610 | ||
2611 | static 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 | ||
2624 | static 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 | ||
2680 | static 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 | ||
2732 | static 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 | */ | |
2763 | static 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); | |
2824 | next_unlock: | |
2825 | spin_unlock_irq(&searchp->spinlock); | |
2826 | next: | |
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 | ||
2837 | static 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 | ||
2872 | static 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 | ||
2880 | static void s_stop(struct seq_file *m, void *p) | |
2881 | { | |
2882 | up(&cache_chain_sem); | |
2883 | } | |
2884 | ||
2885 | static 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 | ||
2985 | struct 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 | */ | |
3000 | ssize_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 | ||
3046 | unsigned 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 | } |