1 // SPDX-License-Identifier: GPL-2.0
4 * Written by Mark Hemment, 1996/97.
5 * (markhe@nextd.demon.co.uk)
7 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
9 * Major cleanup, different bufctl logic, per-cpu arrays
10 * (c) 2000 Manfred Spraul
12 * Cleanup, make the head arrays unconditional, preparation for NUMA
13 * (c) 2002 Manfred Spraul
15 * An implementation of the Slab Allocator as described in outline in;
16 * UNIX Internals: The New Frontiers by Uresh Vahalia
17 * Pub: Prentice Hall ISBN 0-13-101908-2
18 * or with a little more detail in;
19 * The Slab Allocator: An Object-Caching Kernel Memory Allocator
20 * Jeff Bonwick (Sun Microsystems).
21 * Presented at: USENIX Summer 1994 Technical Conference
23 * The memory is organized in caches, one cache for each object type.
24 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
25 * Each cache consists out of many slabs (they are small (usually one
26 * page long) and always contiguous), and each slab contains multiple
27 * initialized objects.
29 * This means, that your constructor is used only for newly allocated
30 * slabs and you must pass objects with the same initializations to
33 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
34 * normal). If you need a special memory type, then must create a new
35 * cache for that memory type.
37 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
38 * full slabs with 0 free objects
40 * empty slabs with no allocated objects
42 * If partial slabs exist, then new allocations come from these slabs,
43 * otherwise from empty slabs or new slabs are allocated.
45 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
46 * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
48 * Each cache has a short per-cpu head array, most allocs
49 * and frees go into that array, and if that array overflows, then 1/2
50 * of the entries in the array are given back into the global cache.
51 * The head array is strictly LIFO and should improve the cache hit rates.
52 * On SMP, it additionally reduces the spinlock operations.
54 * The c_cpuarray may not be read with enabled local interrupts -
55 * it's changed with a smp_call_function().
57 * SMP synchronization:
58 * constructors and destructors are called without any locking.
59 * Several members in struct kmem_cache and struct slab never change, they
60 * are accessed without any locking.
61 * The per-cpu arrays are never accessed from the wrong cpu, no locking,
62 * and local interrupts are disabled so slab code is preempt-safe.
63 * The non-constant members are protected with a per-cache irq spinlock.
65 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
66 * in 2000 - many ideas in the current implementation are derived from
69 * Further notes from the original documentation:
71 * 11 April '97. Started multi-threading - markhe
72 * The global cache-chain is protected by the mutex 'slab_mutex'.
73 * The sem is only needed when accessing/extending the cache-chain, which
74 * can never happen inside an interrupt (kmem_cache_create(),
75 * kmem_cache_shrink() and kmem_cache_reap()).
77 * At present, each engine can be growing a cache. This should be blocked.
79 * 15 March 2005. NUMA slab allocator.
80 * Shai Fultheim <shai@scalex86.org>.
81 * Shobhit Dayal <shobhit@calsoftinc.com>
82 * Alok N Kataria <alokk@calsoftinc.com>
83 * Christoph Lameter <christoph@lameter.com>
85 * Modified the slab allocator to be node aware on NUMA systems.
86 * Each node has its own list of partial, free and full slabs.
87 * All object allocations for a node occur from node specific slab lists.
90 #include <linux/slab.h>
92 #include <linux/poison.h>
93 #include <linux/swap.h>
94 #include <linux/cache.h>
95 #include <linux/interrupt.h>
96 #include <linux/init.h>
97 #include <linux/compiler.h>
98 #include <linux/cpuset.h>
99 #include <linux/proc_fs.h>
100 #include <linux/seq_file.h>
101 #include <linux/notifier.h>
102 #include <linux/kallsyms.h>
103 #include <linux/cpu.h>
104 #include <linux/sysctl.h>
105 #include <linux/module.h>
106 #include <linux/rcupdate.h>
107 #include <linux/string.h>
108 #include <linux/uaccess.h>
109 #include <linux/nodemask.h>
110 #include <linux/kmemleak.h>
111 #include <linux/mempolicy.h>
112 #include <linux/mutex.h>
113 #include <linux/fault-inject.h>
114 #include <linux/rtmutex.h>
115 #include <linux/reciprocal_div.h>
116 #include <linux/debugobjects.h>
117 #include <linux/memory.h>
118 #include <linux/prefetch.h>
119 #include <linux/sched/task_stack.h>
121 #include <net/sock.h>
123 #include <asm/cacheflush.h>
124 #include <asm/tlbflush.h>
125 #include <asm/page.h>
127 #include <trace/events/kmem.h>
129 #include "internal.h"
134 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
135 * 0 for faster, smaller code (especially in the critical paths).
137 * STATS - 1 to collect stats for /proc/slabinfo.
138 * 0 for faster, smaller code (especially in the critical paths).
140 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
143 #ifdef CONFIG_DEBUG_SLAB
146 #define FORCED_DEBUG 1
150 #define FORCED_DEBUG 0
153 /* Shouldn't this be in a header file somewhere? */
154 #define BYTES_PER_WORD sizeof(void *)
155 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
157 #ifndef ARCH_KMALLOC_FLAGS
158 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
161 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \
162 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0)
164 #if FREELIST_BYTE_INDEX
165 typedef unsigned char freelist_idx_t
;
167 typedef unsigned short freelist_idx_t
;
170 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
176 * - LIFO ordering, to hand out cache-warm objects from _alloc
177 * - reduce the number of linked list operations
178 * - reduce spinlock operations
180 * The limit is stored in the per-cpu structure to reduce the data cache
187 unsigned int batchcount
;
188 unsigned int touched
;
190 * Must have this definition in here for the proper
191 * alignment of array_cache. Also simplifies accessing
198 struct array_cache ac
;
202 * Need this for bootstrapping a per node allocator.
204 #define NUM_INIT_LISTS (2 * MAX_NUMNODES)
205 static struct kmem_cache_node __initdata init_kmem_cache_node
[NUM_INIT_LISTS
];
206 #define CACHE_CACHE 0
207 #define SIZE_NODE (MAX_NUMNODES)
209 static int drain_freelist(struct kmem_cache
*cache
,
210 struct kmem_cache_node
*n
, int tofree
);
211 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int len
,
212 int node
, struct list_head
*list
);
213 static void slabs_destroy(struct kmem_cache
*cachep
, struct list_head
*list
);
214 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
);
215 static void cache_reap(struct work_struct
*unused
);
217 static inline void fixup_objfreelist_debug(struct kmem_cache
*cachep
,
219 static inline void fixup_slab_list(struct kmem_cache
*cachep
,
220 struct kmem_cache_node
*n
, struct page
*page
,
222 static int slab_early_init
= 1;
224 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
226 static void kmem_cache_node_init(struct kmem_cache_node
*parent
)
228 INIT_LIST_HEAD(&parent
->slabs_full
);
229 INIT_LIST_HEAD(&parent
->slabs_partial
);
230 INIT_LIST_HEAD(&parent
->slabs_free
);
231 parent
->total_slabs
= 0;
232 parent
->free_slabs
= 0;
233 parent
->shared
= NULL
;
234 parent
->alien
= NULL
;
235 parent
->colour_next
= 0;
236 spin_lock_init(&parent
->list_lock
);
237 parent
->free_objects
= 0;
238 parent
->free_touched
= 0;
241 #define MAKE_LIST(cachep, listp, slab, nodeid) \
243 INIT_LIST_HEAD(listp); \
244 list_splice(&get_node(cachep, nodeid)->slab, listp); \
247 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
249 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
250 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
251 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
254 #define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000U)
255 #define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000U)
256 #define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB)
257 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
259 #define BATCHREFILL_LIMIT 16
261 * Optimization question: fewer reaps means less probability for unnessary
262 * cpucache drain/refill cycles.
264 * OTOH the cpuarrays can contain lots of objects,
265 * which could lock up otherwise freeable slabs.
267 #define REAPTIMEOUT_AC (2*HZ)
268 #define REAPTIMEOUT_NODE (4*HZ)
271 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
272 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
273 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
274 #define STATS_INC_GROWN(x) ((x)->grown++)
275 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y))
276 #define STATS_SET_HIGH(x) \
278 if ((x)->num_active > (x)->high_mark) \
279 (x)->high_mark = (x)->num_active; \
281 #define STATS_INC_ERR(x) ((x)->errors++)
282 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
283 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
284 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
285 #define STATS_SET_FREEABLE(x, i) \
287 if ((x)->max_freeable < i) \
288 (x)->max_freeable = i; \
290 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
291 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
292 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
293 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
295 #define STATS_INC_ACTIVE(x) do { } while (0)
296 #define STATS_DEC_ACTIVE(x) do { } while (0)
297 #define STATS_INC_ALLOCED(x) do { } while (0)
298 #define STATS_INC_GROWN(x) do { } while (0)
299 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0)
300 #define STATS_SET_HIGH(x) do { } while (0)
301 #define STATS_INC_ERR(x) do { } while (0)
302 #define STATS_INC_NODEALLOCS(x) do { } while (0)
303 #define STATS_INC_NODEFREES(x) do { } while (0)
304 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
305 #define STATS_SET_FREEABLE(x, i) do { } while (0)
306 #define STATS_INC_ALLOCHIT(x) do { } while (0)
307 #define STATS_INC_ALLOCMISS(x) do { } while (0)
308 #define STATS_INC_FREEHIT(x) do { } while (0)
309 #define STATS_INC_FREEMISS(x) do { } while (0)
315 * memory layout of objects:
317 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
318 * the end of an object is aligned with the end of the real
319 * allocation. Catches writes behind the end of the allocation.
320 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
322 * cachep->obj_offset: The real object.
323 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
324 * cachep->size - 1* BYTES_PER_WORD: last caller address
325 * [BYTES_PER_WORD long]
327 static int obj_offset(struct kmem_cache
*cachep
)
329 return cachep
->obj_offset
;
332 static unsigned long long *dbg_redzone1(struct kmem_cache
*cachep
, void *objp
)
334 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
335 return (unsigned long long*) (objp
+ obj_offset(cachep
) -
336 sizeof(unsigned long long));
339 static unsigned long long *dbg_redzone2(struct kmem_cache
*cachep
, void *objp
)
341 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
342 if (cachep
->flags
& SLAB_STORE_USER
)
343 return (unsigned long long *)(objp
+ cachep
->size
-
344 sizeof(unsigned long long) -
346 return (unsigned long long *) (objp
+ cachep
->size
-
347 sizeof(unsigned long long));
350 static void **dbg_userword(struct kmem_cache
*cachep
, void *objp
)
352 BUG_ON(!(cachep
->flags
& SLAB_STORE_USER
));
353 return (void **)(objp
+ cachep
->size
- BYTES_PER_WORD
);
358 #define obj_offset(x) 0
359 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
360 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
361 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
366 * Do not go above this order unless 0 objects fit into the slab or
367 * overridden on the command line.
369 #define SLAB_MAX_ORDER_HI 1
370 #define SLAB_MAX_ORDER_LO 0
371 static int slab_max_order
= SLAB_MAX_ORDER_LO
;
372 static bool slab_max_order_set __initdata
;
374 static inline void *index_to_obj(struct kmem_cache
*cache
, struct page
*page
,
377 return page
->s_mem
+ cache
->size
* idx
;
380 #define BOOT_CPUCACHE_ENTRIES 1
381 /* internal cache of cache description objs */
382 static struct kmem_cache kmem_cache_boot
= {
384 .limit
= BOOT_CPUCACHE_ENTRIES
,
386 .size
= sizeof(struct kmem_cache
),
387 .name
= "kmem_cache",
390 static DEFINE_PER_CPU(struct delayed_work
, slab_reap_work
);
392 static inline struct array_cache
*cpu_cache_get(struct kmem_cache
*cachep
)
394 return this_cpu_ptr(cachep
->cpu_cache
);
398 * Calculate the number of objects and left-over bytes for a given buffer size.
400 static unsigned int cache_estimate(unsigned long gfporder
, size_t buffer_size
,
401 slab_flags_t flags
, size_t *left_over
)
404 size_t slab_size
= PAGE_SIZE
<< gfporder
;
407 * The slab management structure can be either off the slab or
408 * on it. For the latter case, the memory allocated for a
411 * - @buffer_size bytes for each object
412 * - One freelist_idx_t for each object
414 * We don't need to consider alignment of freelist because
415 * freelist will be at the end of slab page. The objects will be
416 * at the correct alignment.
418 * If the slab management structure is off the slab, then the
419 * alignment will already be calculated into the size. Because
420 * the slabs are all pages aligned, the objects will be at the
421 * correct alignment when allocated.
423 if (flags
& (CFLGS_OBJFREELIST_SLAB
| CFLGS_OFF_SLAB
)) {
424 num
= slab_size
/ buffer_size
;
425 *left_over
= slab_size
% buffer_size
;
427 num
= slab_size
/ (buffer_size
+ sizeof(freelist_idx_t
));
428 *left_over
= slab_size
%
429 (buffer_size
+ sizeof(freelist_idx_t
));
436 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
438 static void __slab_error(const char *function
, struct kmem_cache
*cachep
,
441 pr_err("slab error in %s(): cache `%s': %s\n",
442 function
, cachep
->name
, msg
);
444 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
449 * By default on NUMA we use alien caches to stage the freeing of
450 * objects allocated from other nodes. This causes massive memory
451 * inefficiencies when using fake NUMA setup to split memory into a
452 * large number of small nodes, so it can be disabled on the command
456 static int use_alien_caches __read_mostly
= 1;
457 static int __init
noaliencache_setup(char *s
)
459 use_alien_caches
= 0;
462 __setup("noaliencache", noaliencache_setup
);
464 static int __init
slab_max_order_setup(char *str
)
466 get_option(&str
, &slab_max_order
);
467 slab_max_order
= slab_max_order
< 0 ? 0 :
468 min(slab_max_order
, MAX_ORDER
- 1);
469 slab_max_order_set
= true;
473 __setup("slab_max_order=", slab_max_order_setup
);
477 * Special reaping functions for NUMA systems called from cache_reap().
478 * These take care of doing round robin flushing of alien caches (containing
479 * objects freed on different nodes from which they were allocated) and the
480 * flushing of remote pcps by calling drain_node_pages.
482 static DEFINE_PER_CPU(unsigned long, slab_reap_node
);
484 static void init_reap_node(int cpu
)
486 per_cpu(slab_reap_node
, cpu
) = next_node_in(cpu_to_mem(cpu
),
490 static void next_reap_node(void)
492 int node
= __this_cpu_read(slab_reap_node
);
494 node
= next_node_in(node
, node_online_map
);
495 __this_cpu_write(slab_reap_node
, node
);
499 #define init_reap_node(cpu) do { } while (0)
500 #define next_reap_node(void) do { } while (0)
504 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
505 * via the workqueue/eventd.
506 * Add the CPU number into the expiration time to minimize the possibility of
507 * the CPUs getting into lockstep and contending for the global cache chain
510 static void start_cpu_timer(int cpu
)
512 struct delayed_work
*reap_work
= &per_cpu(slab_reap_work
, cpu
);
514 if (reap_work
->work
.func
== NULL
) {
516 INIT_DEFERRABLE_WORK(reap_work
, cache_reap
);
517 schedule_delayed_work_on(cpu
, reap_work
,
518 __round_jiffies_relative(HZ
, cpu
));
522 static void init_arraycache(struct array_cache
*ac
, int limit
, int batch
)
527 ac
->batchcount
= batch
;
532 static struct array_cache
*alloc_arraycache(int node
, int entries
,
533 int batchcount
, gfp_t gfp
)
535 size_t memsize
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
536 struct array_cache
*ac
= NULL
;
538 ac
= kmalloc_node(memsize
, gfp
, node
);
540 * The array_cache structures contain pointers to free object.
541 * However, when such objects are allocated or transferred to another
542 * cache the pointers are not cleared and they could be counted as
543 * valid references during a kmemleak scan. Therefore, kmemleak must
544 * not scan such objects.
546 kmemleak_no_scan(ac
);
547 init_arraycache(ac
, entries
, batchcount
);
551 static noinline
void cache_free_pfmemalloc(struct kmem_cache
*cachep
,
552 struct page
*page
, void *objp
)
554 struct kmem_cache_node
*n
;
558 page_node
= page_to_nid(page
);
559 n
= get_node(cachep
, page_node
);
561 spin_lock(&n
->list_lock
);
562 free_block(cachep
, &objp
, 1, page_node
, &list
);
563 spin_unlock(&n
->list_lock
);
565 slabs_destroy(cachep
, &list
);
569 * Transfer objects in one arraycache to another.
570 * Locking must be handled by the caller.
572 * Return the number of entries transferred.
574 static int transfer_objects(struct array_cache
*to
,
575 struct array_cache
*from
, unsigned int max
)
577 /* Figure out how many entries to transfer */
578 int nr
= min3(from
->avail
, max
, to
->limit
- to
->avail
);
583 memcpy(to
->entry
+ to
->avail
, from
->entry
+ from
->avail
-nr
,
591 /* &alien->lock must be held by alien callers. */
592 static __always_inline
void __free_one(struct array_cache
*ac
, void *objp
)
594 /* Avoid trivial double-free. */
595 if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED
) &&
596 WARN_ON_ONCE(ac
->avail
> 0 && ac
->entry
[ac
->avail
- 1] == objp
))
598 ac
->entry
[ac
->avail
++] = objp
;
603 #define drain_alien_cache(cachep, alien) do { } while (0)
604 #define reap_alien(cachep, n) do { } while (0)
606 static inline struct alien_cache
**alloc_alien_cache(int node
,
607 int limit
, gfp_t gfp
)
612 static inline void free_alien_cache(struct alien_cache
**ac_ptr
)
616 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
621 static inline void *alternate_node_alloc(struct kmem_cache
*cachep
,
627 static inline void *____cache_alloc_node(struct kmem_cache
*cachep
,
628 gfp_t flags
, int nodeid
)
633 static inline gfp_t
gfp_exact_node(gfp_t flags
)
635 return flags
& ~__GFP_NOFAIL
;
638 #else /* CONFIG_NUMA */
640 static void *____cache_alloc_node(struct kmem_cache
*, gfp_t
, int);
641 static void *alternate_node_alloc(struct kmem_cache
*, gfp_t
);
643 static struct alien_cache
*__alloc_alien_cache(int node
, int entries
,
644 int batch
, gfp_t gfp
)
646 size_t memsize
= sizeof(void *) * entries
+ sizeof(struct alien_cache
);
647 struct alien_cache
*alc
= NULL
;
649 alc
= kmalloc_node(memsize
, gfp
, node
);
651 kmemleak_no_scan(alc
);
652 init_arraycache(&alc
->ac
, entries
, batch
);
653 spin_lock_init(&alc
->lock
);
658 static struct alien_cache
**alloc_alien_cache(int node
, int limit
, gfp_t gfp
)
660 struct alien_cache
**alc_ptr
;
665 alc_ptr
= kcalloc_node(nr_node_ids
, sizeof(void *), gfp
, node
);
670 if (i
== node
|| !node_online(i
))
672 alc_ptr
[i
] = __alloc_alien_cache(node
, limit
, 0xbaadf00d, gfp
);
674 for (i
--; i
>= 0; i
--)
683 static void free_alien_cache(struct alien_cache
**alc_ptr
)
694 static void __drain_alien_cache(struct kmem_cache
*cachep
,
695 struct array_cache
*ac
, int node
,
696 struct list_head
*list
)
698 struct kmem_cache_node
*n
= get_node(cachep
, node
);
701 spin_lock(&n
->list_lock
);
703 * Stuff objects into the remote nodes shared array first.
704 * That way we could avoid the overhead of putting the objects
705 * into the free lists and getting them back later.
708 transfer_objects(n
->shared
, ac
, ac
->limit
);
710 free_block(cachep
, ac
->entry
, ac
->avail
, node
, list
);
712 spin_unlock(&n
->list_lock
);
717 * Called from cache_reap() to regularly drain alien caches round robin.
719 static void reap_alien(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
)
721 int node
= __this_cpu_read(slab_reap_node
);
724 struct alien_cache
*alc
= n
->alien
[node
];
725 struct array_cache
*ac
;
729 if (ac
->avail
&& spin_trylock_irq(&alc
->lock
)) {
732 __drain_alien_cache(cachep
, ac
, node
, &list
);
733 spin_unlock_irq(&alc
->lock
);
734 slabs_destroy(cachep
, &list
);
740 static void drain_alien_cache(struct kmem_cache
*cachep
,
741 struct alien_cache
**alien
)
744 struct alien_cache
*alc
;
745 struct array_cache
*ac
;
748 for_each_online_node(i
) {
754 spin_lock_irqsave(&alc
->lock
, flags
);
755 __drain_alien_cache(cachep
, ac
, i
, &list
);
756 spin_unlock_irqrestore(&alc
->lock
, flags
);
757 slabs_destroy(cachep
, &list
);
762 static int __cache_free_alien(struct kmem_cache
*cachep
, void *objp
,
763 int node
, int page_node
)
765 struct kmem_cache_node
*n
;
766 struct alien_cache
*alien
= NULL
;
767 struct array_cache
*ac
;
770 n
= get_node(cachep
, node
);
771 STATS_INC_NODEFREES(cachep
);
772 if (n
->alien
&& n
->alien
[page_node
]) {
773 alien
= n
->alien
[page_node
];
775 spin_lock(&alien
->lock
);
776 if (unlikely(ac
->avail
== ac
->limit
)) {
777 STATS_INC_ACOVERFLOW(cachep
);
778 __drain_alien_cache(cachep
, ac
, page_node
, &list
);
780 __free_one(ac
, objp
);
781 spin_unlock(&alien
->lock
);
782 slabs_destroy(cachep
, &list
);
784 n
= get_node(cachep
, page_node
);
785 spin_lock(&n
->list_lock
);
786 free_block(cachep
, &objp
, 1, page_node
, &list
);
787 spin_unlock(&n
->list_lock
);
788 slabs_destroy(cachep
, &list
);
793 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
795 int page_node
= page_to_nid(virt_to_page(objp
));
796 int node
= numa_mem_id();
798 * Make sure we are not freeing a object from another node to the array
801 if (likely(node
== page_node
))
804 return __cache_free_alien(cachep
, objp
, node
, page_node
);
808 * Construct gfp mask to allocate from a specific node but do not reclaim or
809 * warn about failures.
811 static inline gfp_t
gfp_exact_node(gfp_t flags
)
813 return (flags
| __GFP_THISNODE
| __GFP_NOWARN
) & ~(__GFP_RECLAIM
|__GFP_NOFAIL
);
817 static int init_cache_node(struct kmem_cache
*cachep
, int node
, gfp_t gfp
)
819 struct kmem_cache_node
*n
;
822 * Set up the kmem_cache_node for cpu before we can
823 * begin anything. Make sure some other cpu on this
824 * node has not already allocated this
826 n
= get_node(cachep
, node
);
828 spin_lock_irq(&n
->list_lock
);
829 n
->free_limit
= (1 + nr_cpus_node(node
)) * cachep
->batchcount
+
831 spin_unlock_irq(&n
->list_lock
);
836 n
= kmalloc_node(sizeof(struct kmem_cache_node
), gfp
, node
);
840 kmem_cache_node_init(n
);
841 n
->next_reap
= jiffies
+ REAPTIMEOUT_NODE
+
842 ((unsigned long)cachep
) % REAPTIMEOUT_NODE
;
845 (1 + nr_cpus_node(node
)) * cachep
->batchcount
+ cachep
->num
;
848 * The kmem_cache_nodes don't come and go as CPUs
849 * come and go. slab_mutex is sufficient
852 cachep
->node
[node
] = n
;
857 #if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
859 * Allocates and initializes node for a node on each slab cache, used for
860 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
861 * will be allocated off-node since memory is not yet online for the new node.
862 * When hotplugging memory or a cpu, existing node are not replaced if
865 * Must hold slab_mutex.
867 static int init_cache_node_node(int node
)
870 struct kmem_cache
*cachep
;
872 list_for_each_entry(cachep
, &slab_caches
, list
) {
873 ret
= init_cache_node(cachep
, node
, GFP_KERNEL
);
882 static int setup_kmem_cache_node(struct kmem_cache
*cachep
,
883 int node
, gfp_t gfp
, bool force_change
)
886 struct kmem_cache_node
*n
;
887 struct array_cache
*old_shared
= NULL
;
888 struct array_cache
*new_shared
= NULL
;
889 struct alien_cache
**new_alien
= NULL
;
892 if (use_alien_caches
) {
893 new_alien
= alloc_alien_cache(node
, cachep
->limit
, gfp
);
898 if (cachep
->shared
) {
899 new_shared
= alloc_arraycache(node
,
900 cachep
->shared
* cachep
->batchcount
, 0xbaadf00d, gfp
);
905 ret
= init_cache_node(cachep
, node
, gfp
);
909 n
= get_node(cachep
, node
);
910 spin_lock_irq(&n
->list_lock
);
911 if (n
->shared
&& force_change
) {
912 free_block(cachep
, n
->shared
->entry
,
913 n
->shared
->avail
, node
, &list
);
914 n
->shared
->avail
= 0;
917 if (!n
->shared
|| force_change
) {
918 old_shared
= n
->shared
;
919 n
->shared
= new_shared
;
924 n
->alien
= new_alien
;
928 spin_unlock_irq(&n
->list_lock
);
929 slabs_destroy(cachep
, &list
);
932 * To protect lockless access to n->shared during irq disabled context.
933 * If n->shared isn't NULL in irq disabled context, accessing to it is
934 * guaranteed to be valid until irq is re-enabled, because it will be
935 * freed after synchronize_rcu().
937 if (old_shared
&& force_change
)
943 free_alien_cache(new_alien
);
950 static void cpuup_canceled(long cpu
)
952 struct kmem_cache
*cachep
;
953 struct kmem_cache_node
*n
= NULL
;
954 int node
= cpu_to_mem(cpu
);
955 const struct cpumask
*mask
= cpumask_of_node(node
);
957 list_for_each_entry(cachep
, &slab_caches
, list
) {
958 struct array_cache
*nc
;
959 struct array_cache
*shared
;
960 struct alien_cache
**alien
;
963 n
= get_node(cachep
, node
);
967 spin_lock_irq(&n
->list_lock
);
969 /* Free limit for this kmem_cache_node */
970 n
->free_limit
-= cachep
->batchcount
;
972 /* cpu is dead; no one can alloc from it. */
973 nc
= per_cpu_ptr(cachep
->cpu_cache
, cpu
);
974 free_block(cachep
, nc
->entry
, nc
->avail
, node
, &list
);
977 if (!cpumask_empty(mask
)) {
978 spin_unlock_irq(&n
->list_lock
);
984 free_block(cachep
, shared
->entry
,
985 shared
->avail
, node
, &list
);
992 spin_unlock_irq(&n
->list_lock
);
996 drain_alien_cache(cachep
, alien
);
997 free_alien_cache(alien
);
1001 slabs_destroy(cachep
, &list
);
1004 * In the previous loop, all the objects were freed to
1005 * the respective cache's slabs, now we can go ahead and
1006 * shrink each nodelist to its limit.
1008 list_for_each_entry(cachep
, &slab_caches
, list
) {
1009 n
= get_node(cachep
, node
);
1012 drain_freelist(cachep
, n
, INT_MAX
);
1016 static int cpuup_prepare(long cpu
)
1018 struct kmem_cache
*cachep
;
1019 int node
= cpu_to_mem(cpu
);
1023 * We need to do this right in the beginning since
1024 * alloc_arraycache's are going to use this list.
1025 * kmalloc_node allows us to add the slab to the right
1026 * kmem_cache_node and not this cpu's kmem_cache_node
1028 err
= init_cache_node_node(node
);
1033 * Now we can go ahead with allocating the shared arrays and
1036 list_for_each_entry(cachep
, &slab_caches
, list
) {
1037 err
= setup_kmem_cache_node(cachep
, node
, GFP_KERNEL
, false);
1044 cpuup_canceled(cpu
);
1048 int slab_prepare_cpu(unsigned int cpu
)
1052 mutex_lock(&slab_mutex
);
1053 err
= cpuup_prepare(cpu
);
1054 mutex_unlock(&slab_mutex
);
1059 * This is called for a failed online attempt and for a successful
1062 * Even if all the cpus of a node are down, we don't free the
1063 * kmem_cache_node of any cache. This to avoid a race between cpu_down, and
1064 * a kmalloc allocation from another cpu for memory from the node of
1065 * the cpu going down. The list3 structure is usually allocated from
1066 * kmem_cache_create() and gets destroyed at kmem_cache_destroy().
1068 int slab_dead_cpu(unsigned int cpu
)
1070 mutex_lock(&slab_mutex
);
1071 cpuup_canceled(cpu
);
1072 mutex_unlock(&slab_mutex
);
1077 static int slab_online_cpu(unsigned int cpu
)
1079 start_cpu_timer(cpu
);
1083 static int slab_offline_cpu(unsigned int cpu
)
1086 * Shutdown cache reaper. Note that the slab_mutex is held so
1087 * that if cache_reap() is invoked it cannot do anything
1088 * expensive but will only modify reap_work and reschedule the
1091 cancel_delayed_work_sync(&per_cpu(slab_reap_work
, cpu
));
1092 /* Now the cache_reaper is guaranteed to be not running. */
1093 per_cpu(slab_reap_work
, cpu
).work
.func
= NULL
;
1097 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1099 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1100 * Returns -EBUSY if all objects cannot be drained so that the node is not
1103 * Must hold slab_mutex.
1105 static int __meminit
drain_cache_node_node(int node
)
1107 struct kmem_cache
*cachep
;
1110 list_for_each_entry(cachep
, &slab_caches
, list
) {
1111 struct kmem_cache_node
*n
;
1113 n
= get_node(cachep
, node
);
1117 drain_freelist(cachep
, n
, INT_MAX
);
1119 if (!list_empty(&n
->slabs_full
) ||
1120 !list_empty(&n
->slabs_partial
)) {
1128 static int __meminit
slab_memory_callback(struct notifier_block
*self
,
1129 unsigned long action
, void *arg
)
1131 struct memory_notify
*mnb
= arg
;
1135 nid
= mnb
->status_change_nid
;
1140 case MEM_GOING_ONLINE
:
1141 mutex_lock(&slab_mutex
);
1142 ret
= init_cache_node_node(nid
);
1143 mutex_unlock(&slab_mutex
);
1145 case MEM_GOING_OFFLINE
:
1146 mutex_lock(&slab_mutex
);
1147 ret
= drain_cache_node_node(nid
);
1148 mutex_unlock(&slab_mutex
);
1152 case MEM_CANCEL_ONLINE
:
1153 case MEM_CANCEL_OFFLINE
:
1157 return notifier_from_errno(ret
);
1159 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1162 * swap the static kmem_cache_node with kmalloced memory
1164 static void __init
init_list(struct kmem_cache
*cachep
, struct kmem_cache_node
*list
,
1167 struct kmem_cache_node
*ptr
;
1169 ptr
= kmalloc_node(sizeof(struct kmem_cache_node
), GFP_NOWAIT
, nodeid
);
1172 memcpy(ptr
, list
, sizeof(struct kmem_cache_node
));
1174 * Do not assume that spinlocks can be initialized via memcpy:
1176 spin_lock_init(&ptr
->list_lock
);
1178 MAKE_ALL_LISTS(cachep
, ptr
, nodeid
);
1179 cachep
->node
[nodeid
] = ptr
;
1183 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1184 * size of kmem_cache_node.
1186 static void __init
set_up_node(struct kmem_cache
*cachep
, int index
)
1190 for_each_online_node(node
) {
1191 cachep
->node
[node
] = &init_kmem_cache_node
[index
+ node
];
1192 cachep
->node
[node
]->next_reap
= jiffies
+
1194 ((unsigned long)cachep
) % REAPTIMEOUT_NODE
;
1199 * Initialisation. Called after the page allocator have been initialised and
1200 * before smp_init().
1202 void __init
kmem_cache_init(void)
1206 kmem_cache
= &kmem_cache_boot
;
1208 if (!IS_ENABLED(CONFIG_NUMA
) || num_possible_nodes() == 1)
1209 use_alien_caches
= 0;
1211 for (i
= 0; i
< NUM_INIT_LISTS
; i
++)
1212 kmem_cache_node_init(&init_kmem_cache_node
[i
]);
1215 * Fragmentation resistance on low memory - only use bigger
1216 * page orders on machines with more than 32MB of memory if
1217 * not overridden on the command line.
1219 if (!slab_max_order_set
&& totalram_pages() > (32 << 20) >> PAGE_SHIFT
)
1220 slab_max_order
= SLAB_MAX_ORDER_HI
;
1222 /* Bootstrap is tricky, because several objects are allocated
1223 * from caches that do not exist yet:
1224 * 1) initialize the kmem_cache cache: it contains the struct
1225 * kmem_cache structures of all caches, except kmem_cache itself:
1226 * kmem_cache is statically allocated.
1227 * Initially an __init data area is used for the head array and the
1228 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1229 * array at the end of the bootstrap.
1230 * 2) Create the first kmalloc cache.
1231 * The struct kmem_cache for the new cache is allocated normally.
1232 * An __init data area is used for the head array.
1233 * 3) Create the remaining kmalloc caches, with minimally sized
1235 * 4) Replace the __init data head arrays for kmem_cache and the first
1236 * kmalloc cache with kmalloc allocated arrays.
1237 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1238 * the other cache's with kmalloc allocated memory.
1239 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1242 /* 1) create the kmem_cache */
1245 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1247 create_boot_cache(kmem_cache
, "kmem_cache",
1248 offsetof(struct kmem_cache
, node
) +
1249 nr_node_ids
* sizeof(struct kmem_cache_node
*),
1250 SLAB_HWCACHE_ALIGN
, 0, 0);
1251 list_add(&kmem_cache
->list
, &slab_caches
);
1252 slab_state
= PARTIAL
;
1255 * Initialize the caches that provide memory for the kmem_cache_node
1256 * structures first. Without this, further allocations will bug.
1258 kmalloc_caches
[KMALLOC_NORMAL
][INDEX_NODE
] = create_kmalloc_cache(
1259 kmalloc_info
[INDEX_NODE
].name
[KMALLOC_NORMAL
],
1260 kmalloc_info
[INDEX_NODE
].size
,
1261 ARCH_KMALLOC_FLAGS
, 0,
1262 kmalloc_info
[INDEX_NODE
].size
);
1263 slab_state
= PARTIAL_NODE
;
1264 setup_kmalloc_cache_index_table();
1266 slab_early_init
= 0;
1268 /* 5) Replace the bootstrap kmem_cache_node */
1272 for_each_online_node(nid
) {
1273 init_list(kmem_cache
, &init_kmem_cache_node
[CACHE_CACHE
+ nid
], nid
);
1275 init_list(kmalloc_caches
[KMALLOC_NORMAL
][INDEX_NODE
],
1276 &init_kmem_cache_node
[SIZE_NODE
+ nid
], nid
);
1280 create_kmalloc_caches(ARCH_KMALLOC_FLAGS
);
1283 void __init
kmem_cache_init_late(void)
1285 struct kmem_cache
*cachep
;
1287 /* 6) resize the head arrays to their final sizes */
1288 mutex_lock(&slab_mutex
);
1289 list_for_each_entry(cachep
, &slab_caches
, list
)
1290 if (enable_cpucache(cachep
, GFP_NOWAIT
))
1292 mutex_unlock(&slab_mutex
);
1299 * Register a memory hotplug callback that initializes and frees
1302 hotplug_memory_notifier(slab_memory_callback
, SLAB_CALLBACK_PRI
);
1306 * The reap timers are started later, with a module init call: That part
1307 * of the kernel is not yet operational.
1311 static int __init
cpucache_init(void)
1316 * Register the timers that return unneeded pages to the page allocator
1318 ret
= cpuhp_setup_state(CPUHP_AP_ONLINE_DYN
, "SLAB online",
1319 slab_online_cpu
, slab_offline_cpu
);
1324 __initcall(cpucache_init
);
1326 static noinline
void
1327 slab_out_of_memory(struct kmem_cache
*cachep
, gfp_t gfpflags
, int nodeid
)
1330 struct kmem_cache_node
*n
;
1331 unsigned long flags
;
1333 static DEFINE_RATELIMIT_STATE(slab_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
1334 DEFAULT_RATELIMIT_BURST
);
1336 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slab_oom_rs
))
1339 pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
1340 nodeid
, gfpflags
, &gfpflags
);
1341 pr_warn(" cache: %s, object size: %d, order: %d\n",
1342 cachep
->name
, cachep
->size
, cachep
->gfporder
);
1344 for_each_kmem_cache_node(cachep
, node
, n
) {
1345 unsigned long total_slabs
, free_slabs
, free_objs
;
1347 spin_lock_irqsave(&n
->list_lock
, flags
);
1348 total_slabs
= n
->total_slabs
;
1349 free_slabs
= n
->free_slabs
;
1350 free_objs
= n
->free_objects
;
1351 spin_unlock_irqrestore(&n
->list_lock
, flags
);
1353 pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld\n",
1354 node
, total_slabs
- free_slabs
, total_slabs
,
1355 (total_slabs
* cachep
->num
) - free_objs
,
1356 total_slabs
* cachep
->num
);
1362 * Interface to system's page allocator. No need to hold the
1363 * kmem_cache_node ->list_lock.
1365 * If we requested dmaable memory, we will get it. Even if we
1366 * did not request dmaable memory, we might get it, but that
1367 * would be relatively rare and ignorable.
1369 static struct page
*kmem_getpages(struct kmem_cache
*cachep
, gfp_t flags
,
1374 flags
|= cachep
->allocflags
;
1376 page
= __alloc_pages_node(nodeid
, flags
, cachep
->gfporder
);
1378 slab_out_of_memory(cachep
, flags
, nodeid
);
1382 account_slab_page(page
, cachep
->gfporder
, cachep
);
1383 __SetPageSlab(page
);
1384 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1385 if (sk_memalloc_socks() && page_is_pfmemalloc(page
))
1386 SetPageSlabPfmemalloc(page
);
1392 * Interface to system's page release.
1394 static void kmem_freepages(struct kmem_cache
*cachep
, struct page
*page
)
1396 int order
= cachep
->gfporder
;
1398 BUG_ON(!PageSlab(page
));
1399 __ClearPageSlabPfmemalloc(page
);
1400 __ClearPageSlab(page
);
1401 page_mapcount_reset(page
);
1402 page
->mapping
= NULL
;
1404 if (current
->reclaim_state
)
1405 current
->reclaim_state
->reclaimed_slab
+= 1 << order
;
1406 unaccount_slab_page(page
, order
, cachep
);
1407 __free_pages(page
, order
);
1410 static void kmem_rcu_free(struct rcu_head
*head
)
1412 struct kmem_cache
*cachep
;
1415 page
= container_of(head
, struct page
, rcu_head
);
1416 cachep
= page
->slab_cache
;
1418 kmem_freepages(cachep
, page
);
1422 static bool is_debug_pagealloc_cache(struct kmem_cache
*cachep
)
1424 if (debug_pagealloc_enabled_static() && OFF_SLAB(cachep
) &&
1425 (cachep
->size
% PAGE_SIZE
) == 0)
1431 #ifdef CONFIG_DEBUG_PAGEALLOC
1432 static void slab_kernel_map(struct kmem_cache
*cachep
, void *objp
, int map
)
1434 if (!is_debug_pagealloc_cache(cachep
))
1437 kernel_map_pages(virt_to_page(objp
), cachep
->size
/ PAGE_SIZE
, map
);
1441 static inline void slab_kernel_map(struct kmem_cache
*cachep
, void *objp
,
1446 static void poison_obj(struct kmem_cache
*cachep
, void *addr
, unsigned char val
)
1448 int size
= cachep
->object_size
;
1449 addr
= &((char *)addr
)[obj_offset(cachep
)];
1451 memset(addr
, val
, size
);
1452 *(unsigned char *)(addr
+ size
- 1) = POISON_END
;
1455 static void dump_line(char *data
, int offset
, int limit
)
1458 unsigned char error
= 0;
1461 pr_err("%03x: ", offset
);
1462 for (i
= 0; i
< limit
; i
++) {
1463 if (data
[offset
+ i
] != POISON_FREE
) {
1464 error
= data
[offset
+ i
];
1468 print_hex_dump(KERN_CONT
, "", 0, 16, 1,
1469 &data
[offset
], limit
, 1);
1471 if (bad_count
== 1) {
1472 error
^= POISON_FREE
;
1473 if (!(error
& (error
- 1))) {
1474 pr_err("Single bit error detected. Probably bad RAM.\n");
1476 pr_err("Run memtest86+ or a similar memory test tool.\n");
1478 pr_err("Run a memory test tool.\n");
1487 static void print_objinfo(struct kmem_cache
*cachep
, void *objp
, int lines
)
1492 if (cachep
->flags
& SLAB_RED_ZONE
) {
1493 pr_err("Redzone: 0x%llx/0x%llx\n",
1494 *dbg_redzone1(cachep
, objp
),
1495 *dbg_redzone2(cachep
, objp
));
1498 if (cachep
->flags
& SLAB_STORE_USER
)
1499 pr_err("Last user: (%pSR)\n", *dbg_userword(cachep
, objp
));
1500 realobj
= (char *)objp
+ obj_offset(cachep
);
1501 size
= cachep
->object_size
;
1502 for (i
= 0; i
< size
&& lines
; i
+= 16, lines
--) {
1505 if (i
+ limit
> size
)
1507 dump_line(realobj
, i
, limit
);
1511 static void check_poison_obj(struct kmem_cache
*cachep
, void *objp
)
1517 if (is_debug_pagealloc_cache(cachep
))
1520 realobj
= (char *)objp
+ obj_offset(cachep
);
1521 size
= cachep
->object_size
;
1523 for (i
= 0; i
< size
; i
++) {
1524 char exp
= POISON_FREE
;
1527 if (realobj
[i
] != exp
) {
1532 pr_err("Slab corruption (%s): %s start=%px, len=%d\n",
1533 print_tainted(), cachep
->name
,
1535 print_objinfo(cachep
, objp
, 0);
1537 /* Hexdump the affected line */
1540 if (i
+ limit
> size
)
1542 dump_line(realobj
, i
, limit
);
1545 /* Limit to 5 lines */
1551 /* Print some data about the neighboring objects, if they
1554 struct page
*page
= virt_to_head_page(objp
);
1557 objnr
= obj_to_index(cachep
, page
, objp
);
1559 objp
= index_to_obj(cachep
, page
, objnr
- 1);
1560 realobj
= (char *)objp
+ obj_offset(cachep
);
1561 pr_err("Prev obj: start=%px, len=%d\n", realobj
, size
);
1562 print_objinfo(cachep
, objp
, 2);
1564 if (objnr
+ 1 < cachep
->num
) {
1565 objp
= index_to_obj(cachep
, page
, objnr
+ 1);
1566 realobj
= (char *)objp
+ obj_offset(cachep
);
1567 pr_err("Next obj: start=%px, len=%d\n", realobj
, size
);
1568 print_objinfo(cachep
, objp
, 2);
1575 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
,
1580 if (OBJFREELIST_SLAB(cachep
) && cachep
->flags
& SLAB_POISON
) {
1581 poison_obj(cachep
, page
->freelist
- obj_offset(cachep
),
1585 for (i
= 0; i
< cachep
->num
; i
++) {
1586 void *objp
= index_to_obj(cachep
, page
, i
);
1588 if (cachep
->flags
& SLAB_POISON
) {
1589 check_poison_obj(cachep
, objp
);
1590 slab_kernel_map(cachep
, objp
, 1);
1592 if (cachep
->flags
& SLAB_RED_ZONE
) {
1593 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
1594 slab_error(cachep
, "start of a freed object was overwritten");
1595 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
1596 slab_error(cachep
, "end of a freed object was overwritten");
1601 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
,
1608 * slab_destroy - destroy and release all objects in a slab
1609 * @cachep: cache pointer being destroyed
1610 * @page: page pointer being destroyed
1612 * Destroy all the objs in a slab page, and release the mem back to the system.
1613 * Before calling the slab page must have been unlinked from the cache. The
1614 * kmem_cache_node ->list_lock is not held/needed.
1616 static void slab_destroy(struct kmem_cache
*cachep
, struct page
*page
)
1620 freelist
= page
->freelist
;
1621 slab_destroy_debugcheck(cachep
, page
);
1622 if (unlikely(cachep
->flags
& SLAB_TYPESAFE_BY_RCU
))
1623 call_rcu(&page
->rcu_head
, kmem_rcu_free
);
1625 kmem_freepages(cachep
, page
);
1628 * From now on, we don't use freelist
1629 * although actual page can be freed in rcu context
1631 if (OFF_SLAB(cachep
))
1632 kmem_cache_free(cachep
->freelist_cache
, freelist
);
1635 static void slabs_destroy(struct kmem_cache
*cachep
, struct list_head
*list
)
1637 struct page
*page
, *n
;
1639 list_for_each_entry_safe(page
, n
, list
, slab_list
) {
1640 list_del(&page
->slab_list
);
1641 slab_destroy(cachep
, page
);
1646 * calculate_slab_order - calculate size (page order) of slabs
1647 * @cachep: pointer to the cache that is being created
1648 * @size: size of objects to be created in this cache.
1649 * @flags: slab allocation flags
1651 * Also calculates the number of objects per slab.
1653 * This could be made much more intelligent. For now, try to avoid using
1654 * high order pages for slabs. When the gfp() functions are more friendly
1655 * towards high-order requests, this should be changed.
1657 * Return: number of left-over bytes in a slab
1659 static size_t calculate_slab_order(struct kmem_cache
*cachep
,
1660 size_t size
, slab_flags_t flags
)
1662 size_t left_over
= 0;
1665 for (gfporder
= 0; gfporder
<= KMALLOC_MAX_ORDER
; gfporder
++) {
1669 num
= cache_estimate(gfporder
, size
, flags
, &remainder
);
1673 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */
1674 if (num
> SLAB_OBJ_MAX_NUM
)
1677 if (flags
& CFLGS_OFF_SLAB
) {
1678 struct kmem_cache
*freelist_cache
;
1679 size_t freelist_size
;
1681 freelist_size
= num
* sizeof(freelist_idx_t
);
1682 freelist_cache
= kmalloc_slab(freelist_size
, 0u);
1683 if (!freelist_cache
)
1687 * Needed to avoid possible looping condition
1688 * in cache_grow_begin()
1690 if (OFF_SLAB(freelist_cache
))
1693 /* check if off slab has enough benefit */
1694 if (freelist_cache
->size
> cachep
->size
/ 2)
1698 /* Found something acceptable - save it away */
1700 cachep
->gfporder
= gfporder
;
1701 left_over
= remainder
;
1704 * A VFS-reclaimable slab tends to have most allocations
1705 * as GFP_NOFS and we really don't want to have to be allocating
1706 * higher-order pages when we are unable to shrink dcache.
1708 if (flags
& SLAB_RECLAIM_ACCOUNT
)
1712 * Large number of objects is good, but very large slabs are
1713 * currently bad for the gfp()s.
1715 if (gfporder
>= slab_max_order
)
1719 * Acceptable internal fragmentation?
1721 if (left_over
* 8 <= (PAGE_SIZE
<< gfporder
))
1727 static struct array_cache __percpu
*alloc_kmem_cache_cpus(
1728 struct kmem_cache
*cachep
, int entries
, int batchcount
)
1732 struct array_cache __percpu
*cpu_cache
;
1734 size
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
1735 cpu_cache
= __alloc_percpu(size
, sizeof(void *));
1740 for_each_possible_cpu(cpu
) {
1741 init_arraycache(per_cpu_ptr(cpu_cache
, cpu
),
1742 entries
, batchcount
);
1748 static int __ref
setup_cpu_cache(struct kmem_cache
*cachep
, gfp_t gfp
)
1750 if (slab_state
>= FULL
)
1751 return enable_cpucache(cachep
, gfp
);
1753 cachep
->cpu_cache
= alloc_kmem_cache_cpus(cachep
, 1, 1);
1754 if (!cachep
->cpu_cache
)
1757 if (slab_state
== DOWN
) {
1758 /* Creation of first cache (kmem_cache). */
1759 set_up_node(kmem_cache
, CACHE_CACHE
);
1760 } else if (slab_state
== PARTIAL
) {
1761 /* For kmem_cache_node */
1762 set_up_node(cachep
, SIZE_NODE
);
1766 for_each_online_node(node
) {
1767 cachep
->node
[node
] = kmalloc_node(
1768 sizeof(struct kmem_cache_node
), gfp
, node
);
1769 BUG_ON(!cachep
->node
[node
]);
1770 kmem_cache_node_init(cachep
->node
[node
]);
1774 cachep
->node
[numa_mem_id()]->next_reap
=
1775 jiffies
+ REAPTIMEOUT_NODE
+
1776 ((unsigned long)cachep
) % REAPTIMEOUT_NODE
;
1778 cpu_cache_get(cachep
)->avail
= 0;
1779 cpu_cache_get(cachep
)->limit
= BOOT_CPUCACHE_ENTRIES
;
1780 cpu_cache_get(cachep
)->batchcount
= 1;
1781 cpu_cache_get(cachep
)->touched
= 0;
1782 cachep
->batchcount
= 1;
1783 cachep
->limit
= BOOT_CPUCACHE_ENTRIES
;
1787 slab_flags_t
kmem_cache_flags(unsigned int object_size
,
1788 slab_flags_t flags
, const char *name
,
1789 void (*ctor
)(void *))
1795 __kmem_cache_alias(const char *name
, unsigned int size
, unsigned int align
,
1796 slab_flags_t flags
, void (*ctor
)(void *))
1798 struct kmem_cache
*cachep
;
1800 cachep
= find_mergeable(size
, align
, flags
, name
, ctor
);
1805 * Adjust the object sizes so that we clear
1806 * the complete object on kzalloc.
1808 cachep
->object_size
= max_t(int, cachep
->object_size
, size
);
1813 static bool set_objfreelist_slab_cache(struct kmem_cache
*cachep
,
1814 size_t size
, slab_flags_t flags
)
1821 * If slab auto-initialization on free is enabled, store the freelist
1822 * off-slab, so that its contents don't end up in one of the allocated
1825 if (unlikely(slab_want_init_on_free(cachep
)))
1828 if (cachep
->ctor
|| flags
& SLAB_TYPESAFE_BY_RCU
)
1831 left
= calculate_slab_order(cachep
, size
,
1832 flags
| CFLGS_OBJFREELIST_SLAB
);
1836 if (cachep
->num
* sizeof(freelist_idx_t
) > cachep
->object_size
)
1839 cachep
->colour
= left
/ cachep
->colour_off
;
1844 static bool set_off_slab_cache(struct kmem_cache
*cachep
,
1845 size_t size
, slab_flags_t flags
)
1852 * Always use on-slab management when SLAB_NOLEAKTRACE
1853 * to avoid recursive calls into kmemleak.
1855 if (flags
& SLAB_NOLEAKTRACE
)
1859 * Size is large, assume best to place the slab management obj
1860 * off-slab (should allow better packing of objs).
1862 left
= calculate_slab_order(cachep
, size
, flags
| CFLGS_OFF_SLAB
);
1867 * If the slab has been placed off-slab, and we have enough space then
1868 * move it on-slab. This is at the expense of any extra colouring.
1870 if (left
>= cachep
->num
* sizeof(freelist_idx_t
))
1873 cachep
->colour
= left
/ cachep
->colour_off
;
1878 static bool set_on_slab_cache(struct kmem_cache
*cachep
,
1879 size_t size
, slab_flags_t flags
)
1885 left
= calculate_slab_order(cachep
, size
, flags
);
1889 cachep
->colour
= left
/ cachep
->colour_off
;
1895 * __kmem_cache_create - Create a cache.
1896 * @cachep: cache management descriptor
1897 * @flags: SLAB flags
1899 * Returns a ptr to the cache on success, NULL on failure.
1900 * Cannot be called within a int, but can be interrupted.
1901 * The @ctor is run when new pages are allocated by the cache.
1905 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1906 * to catch references to uninitialised memory.
1908 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1909 * for buffer overruns.
1911 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1912 * cacheline. This can be beneficial if you're counting cycles as closely
1915 * Return: a pointer to the created cache or %NULL in case of error
1917 int __kmem_cache_create(struct kmem_cache
*cachep
, slab_flags_t flags
)
1919 size_t ralign
= BYTES_PER_WORD
;
1922 unsigned int size
= cachep
->size
;
1927 * Enable redzoning and last user accounting, except for caches with
1928 * large objects, if the increased size would increase the object size
1929 * above the next power of two: caches with object sizes just above a
1930 * power of two have a significant amount of internal fragmentation.
1932 if (size
< 4096 || fls(size
- 1) == fls(size
-1 + REDZONE_ALIGN
+
1933 2 * sizeof(unsigned long long)))
1934 flags
|= SLAB_RED_ZONE
| SLAB_STORE_USER
;
1935 if (!(flags
& SLAB_TYPESAFE_BY_RCU
))
1936 flags
|= SLAB_POISON
;
1941 * Check that size is in terms of words. This is needed to avoid
1942 * unaligned accesses for some archs when redzoning is used, and makes
1943 * sure any on-slab bufctl's are also correctly aligned.
1945 size
= ALIGN(size
, BYTES_PER_WORD
);
1947 if (flags
& SLAB_RED_ZONE
) {
1948 ralign
= REDZONE_ALIGN
;
1949 /* If redzoning, ensure that the second redzone is suitably
1950 * aligned, by adjusting the object size accordingly. */
1951 size
= ALIGN(size
, REDZONE_ALIGN
);
1954 /* 3) caller mandated alignment */
1955 if (ralign
< cachep
->align
) {
1956 ralign
= cachep
->align
;
1958 /* disable debug if necessary */
1959 if (ralign
> __alignof__(unsigned long long))
1960 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
1964 cachep
->align
= ralign
;
1965 cachep
->colour_off
= cache_line_size();
1966 /* Offset must be a multiple of the alignment. */
1967 if (cachep
->colour_off
< cachep
->align
)
1968 cachep
->colour_off
= cachep
->align
;
1970 if (slab_is_available())
1978 * Both debugging options require word-alignment which is calculated
1981 if (flags
& SLAB_RED_ZONE
) {
1982 /* add space for red zone words */
1983 cachep
->obj_offset
+= sizeof(unsigned long long);
1984 size
+= 2 * sizeof(unsigned long long);
1986 if (flags
& SLAB_STORE_USER
) {
1987 /* user store requires one word storage behind the end of
1988 * the real object. But if the second red zone needs to be
1989 * aligned to 64 bits, we must allow that much space.
1991 if (flags
& SLAB_RED_ZONE
)
1992 size
+= REDZONE_ALIGN
;
1994 size
+= BYTES_PER_WORD
;
1998 kasan_cache_create(cachep
, &size
, &flags
);
2000 size
= ALIGN(size
, cachep
->align
);
2002 * We should restrict the number of objects in a slab to implement
2003 * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition.
2005 if (FREELIST_BYTE_INDEX
&& size
< SLAB_OBJ_MIN_SIZE
)
2006 size
= ALIGN(SLAB_OBJ_MIN_SIZE
, cachep
->align
);
2010 * To activate debug pagealloc, off-slab management is necessary
2011 * requirement. In early phase of initialization, small sized slab
2012 * doesn't get initialized so it would not be possible. So, we need
2013 * to check size >= 256. It guarantees that all necessary small
2014 * sized slab is initialized in current slab initialization sequence.
2016 if (debug_pagealloc_enabled_static() && (flags
& SLAB_POISON
) &&
2017 size
>= 256 && cachep
->object_size
> cache_line_size()) {
2018 if (size
< PAGE_SIZE
|| size
% PAGE_SIZE
== 0) {
2019 size_t tmp_size
= ALIGN(size
, PAGE_SIZE
);
2021 if (set_off_slab_cache(cachep
, tmp_size
, flags
)) {
2022 flags
|= CFLGS_OFF_SLAB
;
2023 cachep
->obj_offset
+= tmp_size
- size
;
2031 if (set_objfreelist_slab_cache(cachep
, size
, flags
)) {
2032 flags
|= CFLGS_OBJFREELIST_SLAB
;
2036 if (set_off_slab_cache(cachep
, size
, flags
)) {
2037 flags
|= CFLGS_OFF_SLAB
;
2041 if (set_on_slab_cache(cachep
, size
, flags
))
2047 cachep
->freelist_size
= cachep
->num
* sizeof(freelist_idx_t
);
2048 cachep
->flags
= flags
;
2049 cachep
->allocflags
= __GFP_COMP
;
2050 if (flags
& SLAB_CACHE_DMA
)
2051 cachep
->allocflags
|= GFP_DMA
;
2052 if (flags
& SLAB_CACHE_DMA32
)
2053 cachep
->allocflags
|= GFP_DMA32
;
2054 if (flags
& SLAB_RECLAIM_ACCOUNT
)
2055 cachep
->allocflags
|= __GFP_RECLAIMABLE
;
2056 cachep
->size
= size
;
2057 cachep
->reciprocal_buffer_size
= reciprocal_value(size
);
2061 * If we're going to use the generic kernel_map_pages()
2062 * poisoning, then it's going to smash the contents of
2063 * the redzone and userword anyhow, so switch them off.
2065 if (IS_ENABLED(CONFIG_PAGE_POISONING
) &&
2066 (cachep
->flags
& SLAB_POISON
) &&
2067 is_debug_pagealloc_cache(cachep
))
2068 cachep
->flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
2071 if (OFF_SLAB(cachep
)) {
2072 cachep
->freelist_cache
=
2073 kmalloc_slab(cachep
->freelist_size
, 0u);
2076 err
= setup_cpu_cache(cachep
, gfp
);
2078 __kmem_cache_release(cachep
);
2086 static void check_irq_off(void)
2088 BUG_ON(!irqs_disabled());
2091 static void check_irq_on(void)
2093 BUG_ON(irqs_disabled());
2096 static void check_mutex_acquired(void)
2098 BUG_ON(!mutex_is_locked(&slab_mutex
));
2101 static void check_spinlock_acquired(struct kmem_cache
*cachep
)
2105 assert_spin_locked(&get_node(cachep
, numa_mem_id())->list_lock
);
2109 static void check_spinlock_acquired_node(struct kmem_cache
*cachep
, int node
)
2113 assert_spin_locked(&get_node(cachep
, node
)->list_lock
);
2118 #define check_irq_off() do { } while(0)
2119 #define check_irq_on() do { } while(0)
2120 #define check_mutex_acquired() do { } while(0)
2121 #define check_spinlock_acquired(x) do { } while(0)
2122 #define check_spinlock_acquired_node(x, y) do { } while(0)
2125 static void drain_array_locked(struct kmem_cache
*cachep
, struct array_cache
*ac
,
2126 int node
, bool free_all
, struct list_head
*list
)
2130 if (!ac
|| !ac
->avail
)
2133 tofree
= free_all
? ac
->avail
: (ac
->limit
+ 4) / 5;
2134 if (tofree
> ac
->avail
)
2135 tofree
= (ac
->avail
+ 1) / 2;
2137 free_block(cachep
, ac
->entry
, tofree
, node
, list
);
2138 ac
->avail
-= tofree
;
2139 memmove(ac
->entry
, &(ac
->entry
[tofree
]), sizeof(void *) * ac
->avail
);
2142 static void do_drain(void *arg
)
2144 struct kmem_cache
*cachep
= arg
;
2145 struct array_cache
*ac
;
2146 int node
= numa_mem_id();
2147 struct kmem_cache_node
*n
;
2151 ac
= cpu_cache_get(cachep
);
2152 n
= get_node(cachep
, node
);
2153 spin_lock(&n
->list_lock
);
2154 free_block(cachep
, ac
->entry
, ac
->avail
, node
, &list
);
2155 spin_unlock(&n
->list_lock
);
2156 slabs_destroy(cachep
, &list
);
2160 static void drain_cpu_caches(struct kmem_cache
*cachep
)
2162 struct kmem_cache_node
*n
;
2166 on_each_cpu(do_drain
, cachep
, 1);
2168 for_each_kmem_cache_node(cachep
, node
, n
)
2170 drain_alien_cache(cachep
, n
->alien
);
2172 for_each_kmem_cache_node(cachep
, node
, n
) {
2173 spin_lock_irq(&n
->list_lock
);
2174 drain_array_locked(cachep
, n
->shared
, node
, true, &list
);
2175 spin_unlock_irq(&n
->list_lock
);
2177 slabs_destroy(cachep
, &list
);
2182 * Remove slabs from the list of free slabs.
2183 * Specify the number of slabs to drain in tofree.
2185 * Returns the actual number of slabs released.
2187 static int drain_freelist(struct kmem_cache
*cache
,
2188 struct kmem_cache_node
*n
, int tofree
)
2190 struct list_head
*p
;
2195 while (nr_freed
< tofree
&& !list_empty(&n
->slabs_free
)) {
2197 spin_lock_irq(&n
->list_lock
);
2198 p
= n
->slabs_free
.prev
;
2199 if (p
== &n
->slabs_free
) {
2200 spin_unlock_irq(&n
->list_lock
);
2204 page
= list_entry(p
, struct page
, slab_list
);
2205 list_del(&page
->slab_list
);
2209 * Safe to drop the lock. The slab is no longer linked
2212 n
->free_objects
-= cache
->num
;
2213 spin_unlock_irq(&n
->list_lock
);
2214 slab_destroy(cache
, page
);
2221 bool __kmem_cache_empty(struct kmem_cache
*s
)
2224 struct kmem_cache_node
*n
;
2226 for_each_kmem_cache_node(s
, node
, n
)
2227 if (!list_empty(&n
->slabs_full
) ||
2228 !list_empty(&n
->slabs_partial
))
2233 int __kmem_cache_shrink(struct kmem_cache
*cachep
)
2237 struct kmem_cache_node
*n
;
2239 drain_cpu_caches(cachep
);
2242 for_each_kmem_cache_node(cachep
, node
, n
) {
2243 drain_freelist(cachep
, n
, INT_MAX
);
2245 ret
+= !list_empty(&n
->slabs_full
) ||
2246 !list_empty(&n
->slabs_partial
);
2248 return (ret
? 1 : 0);
2251 int __kmem_cache_shutdown(struct kmem_cache
*cachep
)
2253 return __kmem_cache_shrink(cachep
);
2256 void __kmem_cache_release(struct kmem_cache
*cachep
)
2259 struct kmem_cache_node
*n
;
2261 cache_random_seq_destroy(cachep
);
2263 free_percpu(cachep
->cpu_cache
);
2265 /* NUMA: free the node structures */
2266 for_each_kmem_cache_node(cachep
, i
, n
) {
2268 free_alien_cache(n
->alien
);
2270 cachep
->node
[i
] = NULL
;
2275 * Get the memory for a slab management obj.
2277 * For a slab cache when the slab descriptor is off-slab, the
2278 * slab descriptor can't come from the same cache which is being created,
2279 * Because if it is the case, that means we defer the creation of
2280 * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.
2281 * And we eventually call down to __kmem_cache_create(), which
2282 * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one.
2283 * This is a "chicken-and-egg" problem.
2285 * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,
2286 * which are all initialized during kmem_cache_init().
2288 static void *alloc_slabmgmt(struct kmem_cache
*cachep
,
2289 struct page
*page
, int colour_off
,
2290 gfp_t local_flags
, int nodeid
)
2293 void *addr
= page_address(page
);
2295 page
->s_mem
= addr
+ colour_off
;
2298 if (OBJFREELIST_SLAB(cachep
))
2300 else if (OFF_SLAB(cachep
)) {
2301 /* Slab management obj is off-slab. */
2302 freelist
= kmem_cache_alloc_node(cachep
->freelist_cache
,
2303 local_flags
, nodeid
);
2307 /* We will use last bytes at the slab for freelist */
2308 freelist
= addr
+ (PAGE_SIZE
<< cachep
->gfporder
) -
2309 cachep
->freelist_size
;
2315 static inline freelist_idx_t
get_free_obj(struct page
*page
, unsigned int idx
)
2317 return ((freelist_idx_t
*)page
->freelist
)[idx
];
2320 static inline void set_free_obj(struct page
*page
,
2321 unsigned int idx
, freelist_idx_t val
)
2323 ((freelist_idx_t
*)(page
->freelist
))[idx
] = val
;
2326 static void cache_init_objs_debug(struct kmem_cache
*cachep
, struct page
*page
)
2331 for (i
= 0; i
< cachep
->num
; i
++) {
2332 void *objp
= index_to_obj(cachep
, page
, i
);
2334 if (cachep
->flags
& SLAB_STORE_USER
)
2335 *dbg_userword(cachep
, objp
) = NULL
;
2337 if (cachep
->flags
& SLAB_RED_ZONE
) {
2338 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2339 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2342 * Constructors are not allowed to allocate memory from the same
2343 * cache which they are a constructor for. Otherwise, deadlock.
2344 * They must also be threaded.
2346 if (cachep
->ctor
&& !(cachep
->flags
& SLAB_POISON
)) {
2347 kasan_unpoison_object_data(cachep
,
2348 objp
+ obj_offset(cachep
));
2349 cachep
->ctor(objp
+ obj_offset(cachep
));
2350 kasan_poison_object_data(
2351 cachep
, objp
+ obj_offset(cachep
));
2354 if (cachep
->flags
& SLAB_RED_ZONE
) {
2355 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2356 slab_error(cachep
, "constructor overwrote the end of an object");
2357 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2358 slab_error(cachep
, "constructor overwrote the start of an object");
2360 /* need to poison the objs? */
2361 if (cachep
->flags
& SLAB_POISON
) {
2362 poison_obj(cachep
, objp
, POISON_FREE
);
2363 slab_kernel_map(cachep
, objp
, 0);
2369 #ifdef CONFIG_SLAB_FREELIST_RANDOM
2370 /* Hold information during a freelist initialization */
2371 union freelist_init_state
{
2377 struct rnd_state rnd_state
;
2381 * Initialize the state based on the randomization methode available.
2382 * return true if the pre-computed list is available, false otherwize.
2384 static bool freelist_state_initialize(union freelist_init_state
*state
,
2385 struct kmem_cache
*cachep
,
2391 /* Use best entropy available to define a random shift */
2392 rand
= get_random_int();
2394 /* Use a random state if the pre-computed list is not available */
2395 if (!cachep
->random_seq
) {
2396 prandom_seed_state(&state
->rnd_state
, rand
);
2399 state
->list
= cachep
->random_seq
;
2400 state
->count
= count
;
2401 state
->pos
= rand
% count
;
2407 /* Get the next entry on the list and randomize it using a random shift */
2408 static freelist_idx_t
next_random_slot(union freelist_init_state
*state
)
2410 if (state
->pos
>= state
->count
)
2412 return state
->list
[state
->pos
++];
2415 /* Swap two freelist entries */
2416 static void swap_free_obj(struct page
*page
, unsigned int a
, unsigned int b
)
2418 swap(((freelist_idx_t
*)page
->freelist
)[a
],
2419 ((freelist_idx_t
*)page
->freelist
)[b
]);
2423 * Shuffle the freelist initialization state based on pre-computed lists.
2424 * return true if the list was successfully shuffled, false otherwise.
2426 static bool shuffle_freelist(struct kmem_cache
*cachep
, struct page
*page
)
2428 unsigned int objfreelist
= 0, i
, rand
, count
= cachep
->num
;
2429 union freelist_init_state state
;
2435 precomputed
= freelist_state_initialize(&state
, cachep
, count
);
2437 /* Take a random entry as the objfreelist */
2438 if (OBJFREELIST_SLAB(cachep
)) {
2440 objfreelist
= count
- 1;
2442 objfreelist
= next_random_slot(&state
);
2443 page
->freelist
= index_to_obj(cachep
, page
, objfreelist
) +
2449 * On early boot, generate the list dynamically.
2450 * Later use a pre-computed list for speed.
2453 for (i
= 0; i
< count
; i
++)
2454 set_free_obj(page
, i
, i
);
2456 /* Fisher-Yates shuffle */
2457 for (i
= count
- 1; i
> 0; i
--) {
2458 rand
= prandom_u32_state(&state
.rnd_state
);
2460 swap_free_obj(page
, i
, rand
);
2463 for (i
= 0; i
< count
; i
++)
2464 set_free_obj(page
, i
, next_random_slot(&state
));
2467 if (OBJFREELIST_SLAB(cachep
))
2468 set_free_obj(page
, cachep
->num
- 1, objfreelist
);
2473 static inline bool shuffle_freelist(struct kmem_cache
*cachep
,
2478 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
2480 static void cache_init_objs(struct kmem_cache
*cachep
,
2487 cache_init_objs_debug(cachep
, page
);
2489 /* Try to randomize the freelist if enabled */
2490 shuffled
= shuffle_freelist(cachep
, page
);
2492 if (!shuffled
&& OBJFREELIST_SLAB(cachep
)) {
2493 page
->freelist
= index_to_obj(cachep
, page
, cachep
->num
- 1) +
2497 for (i
= 0; i
< cachep
->num
; i
++) {
2498 objp
= index_to_obj(cachep
, page
, i
);
2499 objp
= kasan_init_slab_obj(cachep
, objp
);
2501 /* constructor could break poison info */
2502 if (DEBUG
== 0 && cachep
->ctor
) {
2503 kasan_unpoison_object_data(cachep
, objp
);
2505 kasan_poison_object_data(cachep
, objp
);
2509 set_free_obj(page
, i
, i
);
2513 static void *slab_get_obj(struct kmem_cache
*cachep
, struct page
*page
)
2517 objp
= index_to_obj(cachep
, page
, get_free_obj(page
, page
->active
));
2523 static void slab_put_obj(struct kmem_cache
*cachep
,
2524 struct page
*page
, void *objp
)
2526 unsigned int objnr
= obj_to_index(cachep
, page
, objp
);
2530 /* Verify double free bug */
2531 for (i
= page
->active
; i
< cachep
->num
; i
++) {
2532 if (get_free_obj(page
, i
) == objnr
) {
2533 pr_err("slab: double free detected in cache '%s', objp %px\n",
2534 cachep
->name
, objp
);
2540 if (!page
->freelist
)
2541 page
->freelist
= objp
+ obj_offset(cachep
);
2543 set_free_obj(page
, page
->active
, objnr
);
2547 * Map pages beginning at addr to the given cache and slab. This is required
2548 * for the slab allocator to be able to lookup the cache and slab of a
2549 * virtual address for kfree, ksize, and slab debugging.
2551 static void slab_map_pages(struct kmem_cache
*cache
, struct page
*page
,
2554 page
->slab_cache
= cache
;
2555 page
->freelist
= freelist
;
2559 * Grow (by 1) the number of slabs within a cache. This is called by
2560 * kmem_cache_alloc() when there are no active objs left in a cache.
2562 static struct page
*cache_grow_begin(struct kmem_cache
*cachep
,
2563 gfp_t flags
, int nodeid
)
2569 struct kmem_cache_node
*n
;
2573 * Be lazy and only check for valid flags here, keeping it out of the
2574 * critical path in kmem_cache_alloc().
2576 if (unlikely(flags
& GFP_SLAB_BUG_MASK
))
2577 flags
= kmalloc_fix_flags(flags
);
2579 WARN_ON_ONCE(cachep
->ctor
&& (flags
& __GFP_ZERO
));
2580 local_flags
= flags
& (GFP_CONSTRAINT_MASK
|GFP_RECLAIM_MASK
);
2583 if (gfpflags_allow_blocking(local_flags
))
2587 * Get mem for the objs. Attempt to allocate a physical page from
2590 page
= kmem_getpages(cachep
, local_flags
, nodeid
);
2594 page_node
= page_to_nid(page
);
2595 n
= get_node(cachep
, page_node
);
2597 /* Get colour for the slab, and cal the next value. */
2599 if (n
->colour_next
>= cachep
->colour
)
2602 offset
= n
->colour_next
;
2603 if (offset
>= cachep
->colour
)
2606 offset
*= cachep
->colour_off
;
2609 * Call kasan_poison_slab() before calling alloc_slabmgmt(), so
2610 * page_address() in the latter returns a non-tagged pointer,
2611 * as it should be for slab pages.
2613 kasan_poison_slab(page
);
2615 /* Get slab management. */
2616 freelist
= alloc_slabmgmt(cachep
, page
, offset
,
2617 local_flags
& ~GFP_CONSTRAINT_MASK
, page_node
);
2618 if (OFF_SLAB(cachep
) && !freelist
)
2621 slab_map_pages(cachep
, page
, freelist
);
2623 cache_init_objs(cachep
, page
);
2625 if (gfpflags_allow_blocking(local_flags
))
2626 local_irq_disable();
2631 kmem_freepages(cachep
, page
);
2633 if (gfpflags_allow_blocking(local_flags
))
2634 local_irq_disable();
2638 static void cache_grow_end(struct kmem_cache
*cachep
, struct page
*page
)
2640 struct kmem_cache_node
*n
;
2648 INIT_LIST_HEAD(&page
->slab_list
);
2649 n
= get_node(cachep
, page_to_nid(page
));
2651 spin_lock(&n
->list_lock
);
2653 if (!page
->active
) {
2654 list_add_tail(&page
->slab_list
, &n
->slabs_free
);
2657 fixup_slab_list(cachep
, n
, page
, &list
);
2659 STATS_INC_GROWN(cachep
);
2660 n
->free_objects
+= cachep
->num
- page
->active
;
2661 spin_unlock(&n
->list_lock
);
2663 fixup_objfreelist_debug(cachep
, &list
);
2669 * Perform extra freeing checks:
2670 * - detect bad pointers.
2671 * - POISON/RED_ZONE checking
2673 static void kfree_debugcheck(const void *objp
)
2675 if (!virt_addr_valid(objp
)) {
2676 pr_err("kfree_debugcheck: out of range ptr %lxh\n",
2677 (unsigned long)objp
);
2682 static inline void verify_redzone_free(struct kmem_cache
*cache
, void *obj
)
2684 unsigned long long redzone1
, redzone2
;
2686 redzone1
= *dbg_redzone1(cache
, obj
);
2687 redzone2
= *dbg_redzone2(cache
, obj
);
2692 if (redzone1
== RED_ACTIVE
&& redzone2
== RED_ACTIVE
)
2695 if (redzone1
== RED_INACTIVE
&& redzone2
== RED_INACTIVE
)
2696 slab_error(cache
, "double free detected");
2698 slab_error(cache
, "memory outside object was overwritten");
2700 pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
2701 obj
, redzone1
, redzone2
);
2704 static void *cache_free_debugcheck(struct kmem_cache
*cachep
, void *objp
,
2705 unsigned long caller
)
2710 BUG_ON(virt_to_cache(objp
) != cachep
);
2712 objp
-= obj_offset(cachep
);
2713 kfree_debugcheck(objp
);
2714 page
= virt_to_head_page(objp
);
2716 if (cachep
->flags
& SLAB_RED_ZONE
) {
2717 verify_redzone_free(cachep
, objp
);
2718 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2719 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2721 if (cachep
->flags
& SLAB_STORE_USER
)
2722 *dbg_userword(cachep
, objp
) = (void *)caller
;
2724 objnr
= obj_to_index(cachep
, page
, objp
);
2726 BUG_ON(objnr
>= cachep
->num
);
2727 BUG_ON(objp
!= index_to_obj(cachep
, page
, objnr
));
2729 if (cachep
->flags
& SLAB_POISON
) {
2730 poison_obj(cachep
, objp
, POISON_FREE
);
2731 slab_kernel_map(cachep
, objp
, 0);
2737 #define kfree_debugcheck(x) do { } while(0)
2738 #define cache_free_debugcheck(x,objp,z) (objp)
2741 static inline void fixup_objfreelist_debug(struct kmem_cache
*cachep
,
2749 objp
= next
- obj_offset(cachep
);
2750 next
= *(void **)next
;
2751 poison_obj(cachep
, objp
, POISON_FREE
);
2756 static inline void fixup_slab_list(struct kmem_cache
*cachep
,
2757 struct kmem_cache_node
*n
, struct page
*page
,
2760 /* move slabp to correct slabp list: */
2761 list_del(&page
->slab_list
);
2762 if (page
->active
== cachep
->num
) {
2763 list_add(&page
->slab_list
, &n
->slabs_full
);
2764 if (OBJFREELIST_SLAB(cachep
)) {
2766 /* Poisoning will be done without holding the lock */
2767 if (cachep
->flags
& SLAB_POISON
) {
2768 void **objp
= page
->freelist
;
2774 page
->freelist
= NULL
;
2777 list_add(&page
->slab_list
, &n
->slabs_partial
);
2780 /* Try to find non-pfmemalloc slab if needed */
2781 static noinline
struct page
*get_valid_first_slab(struct kmem_cache_node
*n
,
2782 struct page
*page
, bool pfmemalloc
)
2790 if (!PageSlabPfmemalloc(page
))
2793 /* No need to keep pfmemalloc slab if we have enough free objects */
2794 if (n
->free_objects
> n
->free_limit
) {
2795 ClearPageSlabPfmemalloc(page
);
2799 /* Move pfmemalloc slab to the end of list to speed up next search */
2800 list_del(&page
->slab_list
);
2801 if (!page
->active
) {
2802 list_add_tail(&page
->slab_list
, &n
->slabs_free
);
2805 list_add_tail(&page
->slab_list
, &n
->slabs_partial
);
2807 list_for_each_entry(page
, &n
->slabs_partial
, slab_list
) {
2808 if (!PageSlabPfmemalloc(page
))
2812 n
->free_touched
= 1;
2813 list_for_each_entry(page
, &n
->slabs_free
, slab_list
) {
2814 if (!PageSlabPfmemalloc(page
)) {
2823 static struct page
*get_first_slab(struct kmem_cache_node
*n
, bool pfmemalloc
)
2827 assert_spin_locked(&n
->list_lock
);
2828 page
= list_first_entry_or_null(&n
->slabs_partial
, struct page
,
2831 n
->free_touched
= 1;
2832 page
= list_first_entry_or_null(&n
->slabs_free
, struct page
,
2838 if (sk_memalloc_socks())
2839 page
= get_valid_first_slab(n
, page
, pfmemalloc
);
2844 static noinline
void *cache_alloc_pfmemalloc(struct kmem_cache
*cachep
,
2845 struct kmem_cache_node
*n
, gfp_t flags
)
2851 if (!gfp_pfmemalloc_allowed(flags
))
2854 spin_lock(&n
->list_lock
);
2855 page
= get_first_slab(n
, true);
2857 spin_unlock(&n
->list_lock
);
2861 obj
= slab_get_obj(cachep
, page
);
2864 fixup_slab_list(cachep
, n
, page
, &list
);
2866 spin_unlock(&n
->list_lock
);
2867 fixup_objfreelist_debug(cachep
, &list
);
2873 * Slab list should be fixed up by fixup_slab_list() for existing slab
2874 * or cache_grow_end() for new slab
2876 static __always_inline
int alloc_block(struct kmem_cache
*cachep
,
2877 struct array_cache
*ac
, struct page
*page
, int batchcount
)
2880 * There must be at least one object available for
2883 BUG_ON(page
->active
>= cachep
->num
);
2885 while (page
->active
< cachep
->num
&& batchcount
--) {
2886 STATS_INC_ALLOCED(cachep
);
2887 STATS_INC_ACTIVE(cachep
);
2888 STATS_SET_HIGH(cachep
);
2890 ac
->entry
[ac
->avail
++] = slab_get_obj(cachep
, page
);
2896 static void *cache_alloc_refill(struct kmem_cache
*cachep
, gfp_t flags
)
2899 struct kmem_cache_node
*n
;
2900 struct array_cache
*ac
, *shared
;
2906 node
= numa_mem_id();
2908 ac
= cpu_cache_get(cachep
);
2909 batchcount
= ac
->batchcount
;
2910 if (!ac
->touched
&& batchcount
> BATCHREFILL_LIMIT
) {
2912 * If there was little recent activity on this cache, then
2913 * perform only a partial refill. Otherwise we could generate
2916 batchcount
= BATCHREFILL_LIMIT
;
2918 n
= get_node(cachep
, node
);
2920 BUG_ON(ac
->avail
> 0 || !n
);
2921 shared
= READ_ONCE(n
->shared
);
2922 if (!n
->free_objects
&& (!shared
|| !shared
->avail
))
2925 spin_lock(&n
->list_lock
);
2926 shared
= READ_ONCE(n
->shared
);
2928 /* See if we can refill from the shared array */
2929 if (shared
&& transfer_objects(ac
, shared
, batchcount
)) {
2930 shared
->touched
= 1;
2934 while (batchcount
> 0) {
2935 /* Get slab alloc is to come from. */
2936 page
= get_first_slab(n
, false);
2940 check_spinlock_acquired(cachep
);
2942 batchcount
= alloc_block(cachep
, ac
, page
, batchcount
);
2943 fixup_slab_list(cachep
, n
, page
, &list
);
2947 n
->free_objects
-= ac
->avail
;
2949 spin_unlock(&n
->list_lock
);
2950 fixup_objfreelist_debug(cachep
, &list
);
2953 if (unlikely(!ac
->avail
)) {
2954 /* Check if we can use obj in pfmemalloc slab */
2955 if (sk_memalloc_socks()) {
2956 void *obj
= cache_alloc_pfmemalloc(cachep
, n
, flags
);
2962 page
= cache_grow_begin(cachep
, gfp_exact_node(flags
), node
);
2965 * cache_grow_begin() can reenable interrupts,
2966 * then ac could change.
2968 ac
= cpu_cache_get(cachep
);
2969 if (!ac
->avail
&& page
)
2970 alloc_block(cachep
, ac
, page
, batchcount
);
2971 cache_grow_end(cachep
, page
);
2978 return ac
->entry
[--ac
->avail
];
2981 static inline void cache_alloc_debugcheck_before(struct kmem_cache
*cachep
,
2984 might_sleep_if(gfpflags_allow_blocking(flags
));
2988 static void *cache_alloc_debugcheck_after(struct kmem_cache
*cachep
,
2989 gfp_t flags
, void *objp
, unsigned long caller
)
2991 WARN_ON_ONCE(cachep
->ctor
&& (flags
& __GFP_ZERO
));
2994 if (cachep
->flags
& SLAB_POISON
) {
2995 check_poison_obj(cachep
, objp
);
2996 slab_kernel_map(cachep
, objp
, 1);
2997 poison_obj(cachep
, objp
, POISON_INUSE
);
2999 if (cachep
->flags
& SLAB_STORE_USER
)
3000 *dbg_userword(cachep
, objp
) = (void *)caller
;
3002 if (cachep
->flags
& SLAB_RED_ZONE
) {
3003 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
||
3004 *dbg_redzone2(cachep
, objp
) != RED_INACTIVE
) {
3005 slab_error(cachep
, "double free, or memory outside object was overwritten");
3006 pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
3007 objp
, *dbg_redzone1(cachep
, objp
),
3008 *dbg_redzone2(cachep
, objp
));
3010 *dbg_redzone1(cachep
, objp
) = RED_ACTIVE
;
3011 *dbg_redzone2(cachep
, objp
) = RED_ACTIVE
;
3014 objp
+= obj_offset(cachep
);
3015 if (cachep
->ctor
&& cachep
->flags
& SLAB_POISON
)
3017 if (ARCH_SLAB_MINALIGN
&&
3018 ((unsigned long)objp
& (ARCH_SLAB_MINALIGN
-1))) {
3019 pr_err("0x%px: not aligned to ARCH_SLAB_MINALIGN=%d\n",
3020 objp
, (int)ARCH_SLAB_MINALIGN
);
3025 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3028 static inline void *____cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3031 struct array_cache
*ac
;
3035 ac
= cpu_cache_get(cachep
);
3036 if (likely(ac
->avail
)) {
3038 objp
= ac
->entry
[--ac
->avail
];
3040 STATS_INC_ALLOCHIT(cachep
);
3044 STATS_INC_ALLOCMISS(cachep
);
3045 objp
= cache_alloc_refill(cachep
, flags
);
3047 * the 'ac' may be updated by cache_alloc_refill(),
3048 * and kmemleak_erase() requires its correct value.
3050 ac
= cpu_cache_get(cachep
);
3054 * To avoid a false negative, if an object that is in one of the
3055 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3056 * treat the array pointers as a reference to the object.
3059 kmemleak_erase(&ac
->entry
[ac
->avail
]);
3065 * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
3067 * If we are in_interrupt, then process context, including cpusets and
3068 * mempolicy, may not apply and should not be used for allocation policy.
3070 static void *alternate_node_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3072 int nid_alloc
, nid_here
;
3074 if (in_interrupt() || (flags
& __GFP_THISNODE
))
3076 nid_alloc
= nid_here
= numa_mem_id();
3077 if (cpuset_do_slab_mem_spread() && (cachep
->flags
& SLAB_MEM_SPREAD
))
3078 nid_alloc
= cpuset_slab_spread_node();
3079 else if (current
->mempolicy
)
3080 nid_alloc
= mempolicy_slab_node();
3081 if (nid_alloc
!= nid_here
)
3082 return ____cache_alloc_node(cachep
, flags
, nid_alloc
);
3087 * Fallback function if there was no memory available and no objects on a
3088 * certain node and fall back is permitted. First we scan all the
3089 * available node for available objects. If that fails then we
3090 * perform an allocation without specifying a node. This allows the page
3091 * allocator to do its reclaim / fallback magic. We then insert the
3092 * slab into the proper nodelist and then allocate from it.
3094 static void *fallback_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3096 struct zonelist
*zonelist
;
3099 enum zone_type highest_zoneidx
= gfp_zone(flags
);
3103 unsigned int cpuset_mems_cookie
;
3105 if (flags
& __GFP_THISNODE
)
3109 cpuset_mems_cookie
= read_mems_allowed_begin();
3110 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
3114 * Look through allowed nodes for objects available
3115 * from existing per node queues.
3117 for_each_zone_zonelist(zone
, z
, zonelist
, highest_zoneidx
) {
3118 nid
= zone_to_nid(zone
);
3120 if (cpuset_zone_allowed(zone
, flags
) &&
3121 get_node(cache
, nid
) &&
3122 get_node(cache
, nid
)->free_objects
) {
3123 obj
= ____cache_alloc_node(cache
,
3124 gfp_exact_node(flags
), nid
);
3132 * This allocation will be performed within the constraints
3133 * of the current cpuset / memory policy requirements.
3134 * We may trigger various forms of reclaim on the allowed
3135 * set and go into memory reserves if necessary.
3137 page
= cache_grow_begin(cache
, flags
, numa_mem_id());
3138 cache_grow_end(cache
, page
);
3140 nid
= page_to_nid(page
);
3141 obj
= ____cache_alloc_node(cache
,
3142 gfp_exact_node(flags
), nid
);
3145 * Another processor may allocate the objects in
3146 * the slab since we are not holding any locks.
3153 if (unlikely(!obj
&& read_mems_allowed_retry(cpuset_mems_cookie
)))
3159 * A interface to enable slab creation on nodeid
3161 static void *____cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
,
3165 struct kmem_cache_node
*n
;
3169 VM_BUG_ON(nodeid
< 0 || nodeid
>= MAX_NUMNODES
);
3170 n
= get_node(cachep
, nodeid
);
3174 spin_lock(&n
->list_lock
);
3175 page
= get_first_slab(n
, false);
3179 check_spinlock_acquired_node(cachep
, nodeid
);
3181 STATS_INC_NODEALLOCS(cachep
);
3182 STATS_INC_ACTIVE(cachep
);
3183 STATS_SET_HIGH(cachep
);
3185 BUG_ON(page
->active
== cachep
->num
);
3187 obj
= slab_get_obj(cachep
, page
);
3190 fixup_slab_list(cachep
, n
, page
, &list
);
3192 spin_unlock(&n
->list_lock
);
3193 fixup_objfreelist_debug(cachep
, &list
);
3197 spin_unlock(&n
->list_lock
);
3198 page
= cache_grow_begin(cachep
, gfp_exact_node(flags
), nodeid
);
3200 /* This slab isn't counted yet so don't update free_objects */
3201 obj
= slab_get_obj(cachep
, page
);
3203 cache_grow_end(cachep
, page
);
3205 return obj
? obj
: fallback_alloc(cachep
, flags
);
3208 static __always_inline
void *
3209 slab_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
,
3210 unsigned long caller
)
3212 unsigned long save_flags
;
3214 int slab_node
= numa_mem_id();
3215 struct obj_cgroup
*objcg
= NULL
;
3217 flags
&= gfp_allowed_mask
;
3218 cachep
= slab_pre_alloc_hook(cachep
, &objcg
, 1, flags
);
3219 if (unlikely(!cachep
))
3222 cache_alloc_debugcheck_before(cachep
, flags
);
3223 local_irq_save(save_flags
);
3225 if (nodeid
== NUMA_NO_NODE
)
3228 if (unlikely(!get_node(cachep
, nodeid
))) {
3229 /* Node not bootstrapped yet */
3230 ptr
= fallback_alloc(cachep
, flags
);
3234 if (nodeid
== slab_node
) {
3236 * Use the locally cached objects if possible.
3237 * However ____cache_alloc does not allow fallback
3238 * to other nodes. It may fail while we still have
3239 * objects on other nodes available.
3241 ptr
= ____cache_alloc(cachep
, flags
);
3245 /* ___cache_alloc_node can fall back to other nodes */
3246 ptr
= ____cache_alloc_node(cachep
, flags
, nodeid
);
3248 local_irq_restore(save_flags
);
3249 ptr
= cache_alloc_debugcheck_after(cachep
, flags
, ptr
, caller
);
3251 if (unlikely(slab_want_init_on_alloc(flags
, cachep
)) && ptr
)
3252 memset(ptr
, 0, cachep
->object_size
);
3254 slab_post_alloc_hook(cachep
, objcg
, flags
, 1, &ptr
);
3258 static __always_inline
void *
3259 __do_cache_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3263 if (current
->mempolicy
|| cpuset_do_slab_mem_spread()) {
3264 objp
= alternate_node_alloc(cache
, flags
);
3268 objp
= ____cache_alloc(cache
, flags
);
3271 * We may just have run out of memory on the local node.
3272 * ____cache_alloc_node() knows how to locate memory on other nodes
3275 objp
= ____cache_alloc_node(cache
, flags
, numa_mem_id());
3282 static __always_inline
void *
3283 __do_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3285 return ____cache_alloc(cachep
, flags
);
3288 #endif /* CONFIG_NUMA */
3290 static __always_inline
void *
3291 slab_alloc(struct kmem_cache
*cachep
, gfp_t flags
, unsigned long caller
)
3293 unsigned long save_flags
;
3295 struct obj_cgroup
*objcg
= NULL
;
3297 flags
&= gfp_allowed_mask
;
3298 cachep
= slab_pre_alloc_hook(cachep
, &objcg
, 1, flags
);
3299 if (unlikely(!cachep
))
3302 cache_alloc_debugcheck_before(cachep
, flags
);
3303 local_irq_save(save_flags
);
3304 objp
= __do_cache_alloc(cachep
, flags
);
3305 local_irq_restore(save_flags
);
3306 objp
= cache_alloc_debugcheck_after(cachep
, flags
, objp
, caller
);
3309 if (unlikely(slab_want_init_on_alloc(flags
, cachep
)) && objp
)
3310 memset(objp
, 0, cachep
->object_size
);
3312 slab_post_alloc_hook(cachep
, objcg
, flags
, 1, &objp
);
3317 * Caller needs to acquire correct kmem_cache_node's list_lock
3318 * @list: List of detached free slabs should be freed by caller
3320 static void free_block(struct kmem_cache
*cachep
, void **objpp
,
3321 int nr_objects
, int node
, struct list_head
*list
)
3324 struct kmem_cache_node
*n
= get_node(cachep
, node
);
3327 n
->free_objects
+= nr_objects
;
3329 for (i
= 0; i
< nr_objects
; i
++) {
3335 page
= virt_to_head_page(objp
);
3336 list_del(&page
->slab_list
);
3337 check_spinlock_acquired_node(cachep
, node
);
3338 slab_put_obj(cachep
, page
, objp
);
3339 STATS_DEC_ACTIVE(cachep
);
3341 /* fixup slab chains */
3342 if (page
->active
== 0) {
3343 list_add(&page
->slab_list
, &n
->slabs_free
);
3346 /* Unconditionally move a slab to the end of the
3347 * partial list on free - maximum time for the
3348 * other objects to be freed, too.
3350 list_add_tail(&page
->slab_list
, &n
->slabs_partial
);
3354 while (n
->free_objects
> n
->free_limit
&& !list_empty(&n
->slabs_free
)) {
3355 n
->free_objects
-= cachep
->num
;
3357 page
= list_last_entry(&n
->slabs_free
, struct page
, slab_list
);
3358 list_move(&page
->slab_list
, list
);
3364 static void cache_flusharray(struct kmem_cache
*cachep
, struct array_cache
*ac
)
3367 struct kmem_cache_node
*n
;
3368 int node
= numa_mem_id();
3371 batchcount
= ac
->batchcount
;
3374 n
= get_node(cachep
, node
);
3375 spin_lock(&n
->list_lock
);
3377 struct array_cache
*shared_array
= n
->shared
;
3378 int max
= shared_array
->limit
- shared_array
->avail
;
3380 if (batchcount
> max
)
3382 memcpy(&(shared_array
->entry
[shared_array
->avail
]),
3383 ac
->entry
, sizeof(void *) * batchcount
);
3384 shared_array
->avail
+= batchcount
;
3389 free_block(cachep
, ac
->entry
, batchcount
, node
, &list
);
3396 list_for_each_entry(page
, &n
->slabs_free
, slab_list
) {
3397 BUG_ON(page
->active
);
3401 STATS_SET_FREEABLE(cachep
, i
);
3404 spin_unlock(&n
->list_lock
);
3405 slabs_destroy(cachep
, &list
);
3406 ac
->avail
-= batchcount
;
3407 memmove(ac
->entry
, &(ac
->entry
[batchcount
]), sizeof(void *)*ac
->avail
);
3411 * Release an obj back to its cache. If the obj has a constructed state, it must
3412 * be in this state _before_ it is released. Called with disabled ints.
3414 static __always_inline
void __cache_free(struct kmem_cache
*cachep
, void *objp
,
3415 unsigned long caller
)
3417 /* Put the object into the quarantine, don't touch it for now. */
3418 if (kasan_slab_free(cachep
, objp
, _RET_IP_
))
3421 /* Use KCSAN to help debug racy use-after-free. */
3422 if (!(cachep
->flags
& SLAB_TYPESAFE_BY_RCU
))
3423 __kcsan_check_access(objp
, cachep
->object_size
,
3424 KCSAN_ACCESS_WRITE
| KCSAN_ACCESS_ASSERT
);
3426 ___cache_free(cachep
, objp
, caller
);
3429 void ___cache_free(struct kmem_cache
*cachep
, void *objp
,
3430 unsigned long caller
)
3432 struct array_cache
*ac
= cpu_cache_get(cachep
);
3435 if (unlikely(slab_want_init_on_free(cachep
)))
3436 memset(objp
, 0, cachep
->object_size
);
3437 kmemleak_free_recursive(objp
, cachep
->flags
);
3438 objp
= cache_free_debugcheck(cachep
, objp
, caller
);
3439 memcg_slab_free_hook(cachep
, virt_to_head_page(objp
), objp
);
3442 * Skip calling cache_free_alien() when the platform is not numa.
3443 * This will avoid cache misses that happen while accessing slabp (which
3444 * is per page memory reference) to get nodeid. Instead use a global
3445 * variable to skip the call, which is mostly likely to be present in
3448 if (nr_online_nodes
> 1 && cache_free_alien(cachep
, objp
))
3451 if (ac
->avail
< ac
->limit
) {
3452 STATS_INC_FREEHIT(cachep
);
3454 STATS_INC_FREEMISS(cachep
);
3455 cache_flusharray(cachep
, ac
);
3458 if (sk_memalloc_socks()) {
3459 struct page
*page
= virt_to_head_page(objp
);
3461 if (unlikely(PageSlabPfmemalloc(page
))) {
3462 cache_free_pfmemalloc(cachep
, page
, objp
);
3467 __free_one(ac
, objp
);
3471 * kmem_cache_alloc - Allocate an object
3472 * @cachep: The cache to allocate from.
3473 * @flags: See kmalloc().
3475 * Allocate an object from this cache. The flags are only relevant
3476 * if the cache has no available objects.
3478 * Return: pointer to the new object or %NULL in case of error
3480 void *kmem_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3482 void *ret
= slab_alloc(cachep
, flags
, _RET_IP_
);
3484 trace_kmem_cache_alloc(_RET_IP_
, ret
,
3485 cachep
->object_size
, cachep
->size
, flags
);
3489 EXPORT_SYMBOL(kmem_cache_alloc
);
3491 static __always_inline
void
3492 cache_alloc_debugcheck_after_bulk(struct kmem_cache
*s
, gfp_t flags
,
3493 size_t size
, void **p
, unsigned long caller
)
3497 for (i
= 0; i
< size
; i
++)
3498 p
[i
] = cache_alloc_debugcheck_after(s
, flags
, p
[i
], caller
);
3501 int kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t size
,
3505 struct obj_cgroup
*objcg
= NULL
;
3507 s
= slab_pre_alloc_hook(s
, &objcg
, size
, flags
);
3511 cache_alloc_debugcheck_before(s
, flags
);
3513 local_irq_disable();
3514 for (i
= 0; i
< size
; i
++) {
3515 void *objp
= __do_cache_alloc(s
, flags
);
3517 if (unlikely(!objp
))
3523 cache_alloc_debugcheck_after_bulk(s
, flags
, size
, p
, _RET_IP_
);
3525 /* Clear memory outside IRQ disabled section */
3526 if (unlikely(slab_want_init_on_alloc(flags
, s
)))
3527 for (i
= 0; i
< size
; i
++)
3528 memset(p
[i
], 0, s
->object_size
);
3530 slab_post_alloc_hook(s
, objcg
, flags
, size
, p
);
3531 /* FIXME: Trace call missing. Christoph would like a bulk variant */
3535 cache_alloc_debugcheck_after_bulk(s
, flags
, i
, p
, _RET_IP_
);
3536 slab_post_alloc_hook(s
, objcg
, flags
, i
, p
);
3537 __kmem_cache_free_bulk(s
, i
, p
);
3540 EXPORT_SYMBOL(kmem_cache_alloc_bulk
);
3542 #ifdef CONFIG_TRACING
3544 kmem_cache_alloc_trace(struct kmem_cache
*cachep
, gfp_t flags
, size_t size
)
3548 ret
= slab_alloc(cachep
, flags
, _RET_IP_
);
3550 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3551 trace_kmalloc(_RET_IP_
, ret
,
3552 size
, cachep
->size
, flags
);
3555 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
3560 * kmem_cache_alloc_node - Allocate an object on the specified node
3561 * @cachep: The cache to allocate from.
3562 * @flags: See kmalloc().
3563 * @nodeid: node number of the target node.
3565 * Identical to kmem_cache_alloc but it will allocate memory on the given
3566 * node, which can improve the performance for cpu bound structures.
3568 * Fallback to other node is possible if __GFP_THISNODE is not set.
3570 * Return: pointer to the new object or %NULL in case of error
3572 void *kmem_cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
3574 void *ret
= slab_alloc_node(cachep
, flags
, nodeid
, _RET_IP_
);
3576 trace_kmem_cache_alloc_node(_RET_IP_
, ret
,
3577 cachep
->object_size
, cachep
->size
,
3582 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3584 #ifdef CONFIG_TRACING
3585 void *kmem_cache_alloc_node_trace(struct kmem_cache
*cachep
,
3592 ret
= slab_alloc_node(cachep
, flags
, nodeid
, _RET_IP_
);
3594 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3595 trace_kmalloc_node(_RET_IP_
, ret
,
3600 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
3603 static __always_inline
void *
3604 __do_kmalloc_node(size_t size
, gfp_t flags
, int node
, unsigned long caller
)
3606 struct kmem_cache
*cachep
;
3609 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3611 cachep
= kmalloc_slab(size
, flags
);
3612 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3614 ret
= kmem_cache_alloc_node_trace(cachep
, flags
, node
, size
);
3615 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3620 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3622 return __do_kmalloc_node(size
, flags
, node
, _RET_IP_
);
3624 EXPORT_SYMBOL(__kmalloc_node
);
3626 void *__kmalloc_node_track_caller(size_t size
, gfp_t flags
,
3627 int node
, unsigned long caller
)
3629 return __do_kmalloc_node(size
, flags
, node
, caller
);
3631 EXPORT_SYMBOL(__kmalloc_node_track_caller
);
3632 #endif /* CONFIG_NUMA */
3635 * __do_kmalloc - allocate memory
3636 * @size: how many bytes of memory are required.
3637 * @flags: the type of memory to allocate (see kmalloc).
3638 * @caller: function caller for debug tracking of the caller
3640 * Return: pointer to the allocated memory or %NULL in case of error
3642 static __always_inline
void *__do_kmalloc(size_t size
, gfp_t flags
,
3643 unsigned long caller
)
3645 struct kmem_cache
*cachep
;
3648 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3650 cachep
= kmalloc_slab(size
, flags
);
3651 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3653 ret
= slab_alloc(cachep
, flags
, caller
);
3655 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3656 trace_kmalloc(caller
, ret
,
3657 size
, cachep
->size
, flags
);
3662 void *__kmalloc(size_t size
, gfp_t flags
)
3664 return __do_kmalloc(size
, flags
, _RET_IP_
);
3666 EXPORT_SYMBOL(__kmalloc
);
3668 void *__kmalloc_track_caller(size_t size
, gfp_t flags
, unsigned long caller
)
3670 return __do_kmalloc(size
, flags
, caller
);
3672 EXPORT_SYMBOL(__kmalloc_track_caller
);
3675 * kmem_cache_free - Deallocate an object
3676 * @cachep: The cache the allocation was from.
3677 * @objp: The previously allocated object.
3679 * Free an object which was previously allocated from this
3682 void kmem_cache_free(struct kmem_cache
*cachep
, void *objp
)
3684 unsigned long flags
;
3685 cachep
= cache_from_obj(cachep
, objp
);
3689 local_irq_save(flags
);
3690 debug_check_no_locks_freed(objp
, cachep
->object_size
);
3691 if (!(cachep
->flags
& SLAB_DEBUG_OBJECTS
))
3692 debug_check_no_obj_freed(objp
, cachep
->object_size
);
3693 __cache_free(cachep
, objp
, _RET_IP_
);
3694 local_irq_restore(flags
);
3696 trace_kmem_cache_free(_RET_IP_
, objp
);
3698 EXPORT_SYMBOL(kmem_cache_free
);
3700 void kmem_cache_free_bulk(struct kmem_cache
*orig_s
, size_t size
, void **p
)
3702 struct kmem_cache
*s
;
3705 local_irq_disable();
3706 for (i
= 0; i
< size
; i
++) {
3709 if (!orig_s
) /* called via kfree_bulk */
3710 s
= virt_to_cache(objp
);
3712 s
= cache_from_obj(orig_s
, objp
);
3716 debug_check_no_locks_freed(objp
, s
->object_size
);
3717 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
3718 debug_check_no_obj_freed(objp
, s
->object_size
);
3720 __cache_free(s
, objp
, _RET_IP_
);
3724 /* FIXME: add tracing */
3726 EXPORT_SYMBOL(kmem_cache_free_bulk
);
3729 * kfree - free previously allocated memory
3730 * @objp: pointer returned by kmalloc.
3732 * If @objp is NULL, no operation is performed.
3734 * Don't free memory not originally allocated by kmalloc()
3735 * or you will run into trouble.
3737 void kfree(const void *objp
)
3739 struct kmem_cache
*c
;
3740 unsigned long flags
;
3742 trace_kfree(_RET_IP_
, objp
);
3744 if (unlikely(ZERO_OR_NULL_PTR(objp
)))
3746 local_irq_save(flags
);
3747 kfree_debugcheck(objp
);
3748 c
= virt_to_cache(objp
);
3750 local_irq_restore(flags
);
3753 debug_check_no_locks_freed(objp
, c
->object_size
);
3755 debug_check_no_obj_freed(objp
, c
->object_size
);
3756 __cache_free(c
, (void *)objp
, _RET_IP_
);
3757 local_irq_restore(flags
);
3759 EXPORT_SYMBOL(kfree
);
3762 * This initializes kmem_cache_node or resizes various caches for all nodes.
3764 static int setup_kmem_cache_nodes(struct kmem_cache
*cachep
, gfp_t gfp
)
3768 struct kmem_cache_node
*n
;
3770 for_each_online_node(node
) {
3771 ret
= setup_kmem_cache_node(cachep
, node
, gfp
, true);
3780 if (!cachep
->list
.next
) {
3781 /* Cache is not active yet. Roll back what we did */
3784 n
= get_node(cachep
, node
);
3787 free_alien_cache(n
->alien
);
3789 cachep
->node
[node
] = NULL
;
3797 /* Always called with the slab_mutex held */
3798 static int do_tune_cpucache(struct kmem_cache
*cachep
, int limit
,
3799 int batchcount
, int shared
, gfp_t gfp
)
3801 struct array_cache __percpu
*cpu_cache
, *prev
;
3804 cpu_cache
= alloc_kmem_cache_cpus(cachep
, limit
, batchcount
);
3808 prev
= cachep
->cpu_cache
;
3809 cachep
->cpu_cache
= cpu_cache
;
3811 * Without a previous cpu_cache there's no need to synchronize remote
3812 * cpus, so skip the IPIs.
3815 kick_all_cpus_sync();
3818 cachep
->batchcount
= batchcount
;
3819 cachep
->limit
= limit
;
3820 cachep
->shared
= shared
;
3825 for_each_online_cpu(cpu
) {
3828 struct kmem_cache_node
*n
;
3829 struct array_cache
*ac
= per_cpu_ptr(prev
, cpu
);
3831 node
= cpu_to_mem(cpu
);
3832 n
= get_node(cachep
, node
);
3833 spin_lock_irq(&n
->list_lock
);
3834 free_block(cachep
, ac
->entry
, ac
->avail
, node
, &list
);
3835 spin_unlock_irq(&n
->list_lock
);
3836 slabs_destroy(cachep
, &list
);
3841 return setup_kmem_cache_nodes(cachep
, gfp
);
3844 /* Called with slab_mutex held always */
3845 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
)
3852 err
= cache_random_seq_create(cachep
, cachep
->num
, gfp
);
3856 if (limit
&& shared
&& batchcount
)
3859 * The head array serves three purposes:
3860 * - create a LIFO ordering, i.e. return objects that are cache-warm
3861 * - reduce the number of spinlock operations.
3862 * - reduce the number of linked list operations on the slab and
3863 * bufctl chains: array operations are cheaper.
3864 * The numbers are guessed, we should auto-tune as described by
3867 if (cachep
->size
> 131072)
3869 else if (cachep
->size
> PAGE_SIZE
)
3871 else if (cachep
->size
> 1024)
3873 else if (cachep
->size
> 256)
3879 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3880 * allocation behaviour: Most allocs on one cpu, most free operations
3881 * on another cpu. For these cases, an efficient object passing between
3882 * cpus is necessary. This is provided by a shared array. The array
3883 * replaces Bonwick's magazine layer.
3884 * On uniprocessor, it's functionally equivalent (but less efficient)
3885 * to a larger limit. Thus disabled by default.
3888 if (cachep
->size
<= PAGE_SIZE
&& num_possible_cpus() > 1)
3893 * With debugging enabled, large batchcount lead to excessively long
3894 * periods with disabled local interrupts. Limit the batchcount
3899 batchcount
= (limit
+ 1) / 2;
3901 err
= do_tune_cpucache(cachep
, limit
, batchcount
, shared
, gfp
);
3904 pr_err("enable_cpucache failed for %s, error %d\n",
3905 cachep
->name
, -err
);
3910 * Drain an array if it contains any elements taking the node lock only if
3911 * necessary. Note that the node listlock also protects the array_cache
3912 * if drain_array() is used on the shared array.
3914 static void drain_array(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
,
3915 struct array_cache
*ac
, int node
)
3919 /* ac from n->shared can be freed if we don't hold the slab_mutex. */
3920 check_mutex_acquired();
3922 if (!ac
|| !ac
->avail
)
3930 spin_lock_irq(&n
->list_lock
);
3931 drain_array_locked(cachep
, ac
, node
, false, &list
);
3932 spin_unlock_irq(&n
->list_lock
);
3934 slabs_destroy(cachep
, &list
);
3938 * cache_reap - Reclaim memory from caches.
3939 * @w: work descriptor
3941 * Called from workqueue/eventd every few seconds.
3943 * - clear the per-cpu caches for this CPU.
3944 * - return freeable pages to the main free memory pool.
3946 * If we cannot acquire the cache chain mutex then just give up - we'll try
3947 * again on the next iteration.
3949 static void cache_reap(struct work_struct
*w
)
3951 struct kmem_cache
*searchp
;
3952 struct kmem_cache_node
*n
;
3953 int node
= numa_mem_id();
3954 struct delayed_work
*work
= to_delayed_work(w
);
3956 if (!mutex_trylock(&slab_mutex
))
3957 /* Give up. Setup the next iteration. */
3960 list_for_each_entry(searchp
, &slab_caches
, list
) {
3964 * We only take the node lock if absolutely necessary and we
3965 * have established with reasonable certainty that
3966 * we can do some work if the lock was obtained.
3968 n
= get_node(searchp
, node
);
3970 reap_alien(searchp
, n
);
3972 drain_array(searchp
, n
, cpu_cache_get(searchp
), node
);
3975 * These are racy checks but it does not matter
3976 * if we skip one check or scan twice.
3978 if (time_after(n
->next_reap
, jiffies
))
3981 n
->next_reap
= jiffies
+ REAPTIMEOUT_NODE
;
3983 drain_array(searchp
, n
, n
->shared
, node
);
3985 if (n
->free_touched
)
3986 n
->free_touched
= 0;
3990 freed
= drain_freelist(searchp
, n
, (n
->free_limit
+
3991 5 * searchp
->num
- 1) / (5 * searchp
->num
));
3992 STATS_ADD_REAPED(searchp
, freed
);
3998 mutex_unlock(&slab_mutex
);
4001 /* Set up the next iteration */
4002 schedule_delayed_work_on(smp_processor_id(), work
,
4003 round_jiffies_relative(REAPTIMEOUT_AC
));
4006 void get_slabinfo(struct kmem_cache
*cachep
, struct slabinfo
*sinfo
)
4008 unsigned long active_objs
, num_objs
, active_slabs
;
4009 unsigned long total_slabs
= 0, free_objs
= 0, shared_avail
= 0;
4010 unsigned long free_slabs
= 0;
4012 struct kmem_cache_node
*n
;
4014 for_each_kmem_cache_node(cachep
, node
, n
) {
4016 spin_lock_irq(&n
->list_lock
);
4018 total_slabs
+= n
->total_slabs
;
4019 free_slabs
+= n
->free_slabs
;
4020 free_objs
+= n
->free_objects
;
4023 shared_avail
+= n
->shared
->avail
;
4025 spin_unlock_irq(&n
->list_lock
);
4027 num_objs
= total_slabs
* cachep
->num
;
4028 active_slabs
= total_slabs
- free_slabs
;
4029 active_objs
= num_objs
- free_objs
;
4031 sinfo
->active_objs
= active_objs
;
4032 sinfo
->num_objs
= num_objs
;
4033 sinfo
->active_slabs
= active_slabs
;
4034 sinfo
->num_slabs
= total_slabs
;
4035 sinfo
->shared_avail
= shared_avail
;
4036 sinfo
->limit
= cachep
->limit
;
4037 sinfo
->batchcount
= cachep
->batchcount
;
4038 sinfo
->shared
= cachep
->shared
;
4039 sinfo
->objects_per_slab
= cachep
->num
;
4040 sinfo
->cache_order
= cachep
->gfporder
;
4043 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*cachep
)
4047 unsigned long high
= cachep
->high_mark
;
4048 unsigned long allocs
= cachep
->num_allocations
;
4049 unsigned long grown
= cachep
->grown
;
4050 unsigned long reaped
= cachep
->reaped
;
4051 unsigned long errors
= cachep
->errors
;
4052 unsigned long max_freeable
= cachep
->max_freeable
;
4053 unsigned long node_allocs
= cachep
->node_allocs
;
4054 unsigned long node_frees
= cachep
->node_frees
;
4055 unsigned long overflows
= cachep
->node_overflow
;
4057 seq_printf(m
, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu",
4058 allocs
, high
, grown
,
4059 reaped
, errors
, max_freeable
, node_allocs
,
4060 node_frees
, overflows
);
4064 unsigned long allochit
= atomic_read(&cachep
->allochit
);
4065 unsigned long allocmiss
= atomic_read(&cachep
->allocmiss
);
4066 unsigned long freehit
= atomic_read(&cachep
->freehit
);
4067 unsigned long freemiss
= atomic_read(&cachep
->freemiss
);
4069 seq_printf(m
, " : cpustat %6lu %6lu %6lu %6lu",
4070 allochit
, allocmiss
, freehit
, freemiss
);
4075 #define MAX_SLABINFO_WRITE 128
4077 * slabinfo_write - Tuning for the slab allocator
4079 * @buffer: user buffer
4080 * @count: data length
4083 * Return: %0 on success, negative error code otherwise.
4085 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
4086 size_t count
, loff_t
*ppos
)
4088 char kbuf
[MAX_SLABINFO_WRITE
+ 1], *tmp
;
4089 int limit
, batchcount
, shared
, res
;
4090 struct kmem_cache
*cachep
;
4092 if (count
> MAX_SLABINFO_WRITE
)
4094 if (copy_from_user(&kbuf
, buffer
, count
))
4096 kbuf
[MAX_SLABINFO_WRITE
] = '\0';
4098 tmp
= strchr(kbuf
, ' ');
4103 if (sscanf(tmp
, " %d %d %d", &limit
, &batchcount
, &shared
) != 3)
4106 /* Find the cache in the chain of caches. */
4107 mutex_lock(&slab_mutex
);
4109 list_for_each_entry(cachep
, &slab_caches
, list
) {
4110 if (!strcmp(cachep
->name
, kbuf
)) {
4111 if (limit
< 1 || batchcount
< 1 ||
4112 batchcount
> limit
|| shared
< 0) {
4115 res
= do_tune_cpucache(cachep
, limit
,
4122 mutex_unlock(&slab_mutex
);
4128 #ifdef CONFIG_HARDENED_USERCOPY
4130 * Rejects incorrectly sized objects and objects that are to be copied
4131 * to/from userspace but do not fall entirely within the containing slab
4132 * cache's usercopy region.
4134 * Returns NULL if check passes, otherwise const char * to name of cache
4135 * to indicate an error.
4137 void __check_heap_object(const void *ptr
, unsigned long n
, struct page
*page
,
4140 struct kmem_cache
*cachep
;
4142 unsigned long offset
;
4144 ptr
= kasan_reset_tag(ptr
);
4146 /* Find and validate object. */
4147 cachep
= page
->slab_cache
;
4148 objnr
= obj_to_index(cachep
, page
, (void *)ptr
);
4149 BUG_ON(objnr
>= cachep
->num
);
4151 /* Find offset within object. */
4152 offset
= ptr
- index_to_obj(cachep
, page
, objnr
) - obj_offset(cachep
);
4154 /* Allow address range falling entirely within usercopy region. */
4155 if (offset
>= cachep
->useroffset
&&
4156 offset
- cachep
->useroffset
<= cachep
->usersize
&&
4157 n
<= cachep
->useroffset
- offset
+ cachep
->usersize
)
4161 * If the copy is still within the allocated object, produce
4162 * a warning instead of rejecting the copy. This is intended
4163 * to be a temporary method to find any missing usercopy
4166 if (usercopy_fallback
&&
4167 offset
<= cachep
->object_size
&&
4168 n
<= cachep
->object_size
- offset
) {
4169 usercopy_warn("SLAB object", cachep
->name
, to_user
, offset
, n
);
4173 usercopy_abort("SLAB object", cachep
->name
, to_user
, offset
, n
);
4175 #endif /* CONFIG_HARDENED_USERCOPY */
4178 * __ksize -- Uninstrumented ksize.
4179 * @objp: pointer to the object
4181 * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
4182 * safety checks as ksize() with KASAN instrumentation enabled.
4184 * Return: size of the actual memory used by @objp in bytes
4186 size_t __ksize(const void *objp
)
4188 struct kmem_cache
*c
;
4192 if (unlikely(objp
== ZERO_SIZE_PTR
))
4195 c
= virt_to_cache(objp
);
4196 size
= c
? c
->object_size
: 0;
4200 EXPORT_SYMBOL(__ksize
);