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/kfence.h>
104 #include <linux/cpu.h>
105 #include <linux/sysctl.h>
106 #include <linux/module.h>
107 #include <linux/rcupdate.h>
108 #include <linux/string.h>
109 #include <linux/uaccess.h>
110 #include <linux/nodemask.h>
111 #include <linux/kmemleak.h>
112 #include <linux/mempolicy.h>
113 #include <linux/mutex.h>
114 #include <linux/fault-inject.h>
115 #include <linux/rtmutex.h>
116 #include <linux/reciprocal_div.h>
117 #include <linux/debugobjects.h>
118 #include <linux/memory.h>
119 #include <linux/prefetch.h>
120 #include <linux/sched/task_stack.h>
122 #include <net/sock.h>
124 #include <asm/cacheflush.h>
125 #include <asm/tlbflush.h>
126 #include <asm/page.h>
128 #include <trace/events/kmem.h>
130 #include "internal.h"
135 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON.
136 * 0 for faster, smaller code (especially in the critical paths).
138 * STATS - 1 to collect stats for /proc/slabinfo.
139 * 0 for faster, smaller code (especially in the critical paths).
141 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
144 #ifdef CONFIG_DEBUG_SLAB
147 #define FORCED_DEBUG 1
151 #define FORCED_DEBUG 0
154 /* Shouldn't this be in a header file somewhere? */
155 #define BYTES_PER_WORD sizeof(void *)
156 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
158 #ifndef ARCH_KMALLOC_FLAGS
159 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
162 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \
163 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0)
165 #if FREELIST_BYTE_INDEX
166 typedef unsigned char freelist_idx_t
;
168 typedef unsigned short freelist_idx_t
;
171 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
177 * - LIFO ordering, to hand out cache-warm objects from _alloc
178 * - reduce the number of linked list operations
179 * - reduce spinlock operations
181 * The limit is stored in the per-cpu structure to reduce the data cache
188 unsigned int batchcount
;
189 unsigned int touched
;
191 * Must have this definition in here for the proper
192 * alignment of array_cache. Also simplifies accessing
199 struct array_cache ac
;
203 * Need this for bootstrapping a per node allocator.
205 #define NUM_INIT_LISTS (2 * MAX_NUMNODES)
206 static struct kmem_cache_node __initdata init_kmem_cache_node
[NUM_INIT_LISTS
];
207 #define CACHE_CACHE 0
208 #define SIZE_NODE (MAX_NUMNODES)
210 static int drain_freelist(struct kmem_cache
*cache
,
211 struct kmem_cache_node
*n
, int tofree
);
212 static void free_block(struct kmem_cache
*cachep
, void **objpp
, int len
,
213 int node
, struct list_head
*list
);
214 static void slabs_destroy(struct kmem_cache
*cachep
, struct list_head
*list
);
215 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
);
216 static void cache_reap(struct work_struct
*unused
);
218 static inline void fixup_objfreelist_debug(struct kmem_cache
*cachep
,
220 static inline void fixup_slab_list(struct kmem_cache
*cachep
,
221 struct kmem_cache_node
*n
, struct slab
*slab
,
223 static int slab_early_init
= 1;
225 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
227 static void kmem_cache_node_init(struct kmem_cache_node
*parent
)
229 INIT_LIST_HEAD(&parent
->slabs_full
);
230 INIT_LIST_HEAD(&parent
->slabs_partial
);
231 INIT_LIST_HEAD(&parent
->slabs_free
);
232 parent
->total_slabs
= 0;
233 parent
->free_slabs
= 0;
234 parent
->shared
= NULL
;
235 parent
->alien
= NULL
;
236 parent
->colour_next
= 0;
237 spin_lock_init(&parent
->list_lock
);
238 parent
->free_objects
= 0;
239 parent
->free_touched
= 0;
242 #define MAKE_LIST(cachep, listp, slab, nodeid) \
244 INIT_LIST_HEAD(listp); \
245 list_splice(&get_node(cachep, nodeid)->slab, listp); \
248 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
250 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
251 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
252 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
255 #define CFLGS_OBJFREELIST_SLAB ((slab_flags_t __force)0x40000000U)
256 #define CFLGS_OFF_SLAB ((slab_flags_t __force)0x80000000U)
257 #define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB)
258 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
260 #define BATCHREFILL_LIMIT 16
262 * Optimization question: fewer reaps means less probability for unnecessary
263 * cpucache drain/refill cycles.
265 * OTOH the cpuarrays can contain lots of objects,
266 * which could lock up otherwise freeable slabs.
268 #define REAPTIMEOUT_AC (2*HZ)
269 #define REAPTIMEOUT_NODE (4*HZ)
272 #define STATS_INC_ACTIVE(x) ((x)->num_active++)
273 #define STATS_DEC_ACTIVE(x) ((x)->num_active--)
274 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
275 #define STATS_INC_GROWN(x) ((x)->grown++)
276 #define STATS_ADD_REAPED(x, y) ((x)->reaped += (y))
277 #define STATS_SET_HIGH(x) \
279 if ((x)->num_active > (x)->high_mark) \
280 (x)->high_mark = (x)->num_active; \
282 #define STATS_INC_ERR(x) ((x)->errors++)
283 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++)
284 #define STATS_INC_NODEFREES(x) ((x)->node_frees++)
285 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
286 #define STATS_SET_FREEABLE(x, i) \
288 if ((x)->max_freeable < i) \
289 (x)->max_freeable = i; \
291 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit)
292 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss)
293 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit)
294 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss)
296 #define STATS_INC_ACTIVE(x) do { } while (0)
297 #define STATS_DEC_ACTIVE(x) do { } while (0)
298 #define STATS_INC_ALLOCED(x) do { } while (0)
299 #define STATS_INC_GROWN(x) do { } while (0)
300 #define STATS_ADD_REAPED(x, y) do { (void)(y); } while (0)
301 #define STATS_SET_HIGH(x) do { } while (0)
302 #define STATS_INC_ERR(x) do { } while (0)
303 #define STATS_INC_NODEALLOCS(x) do { } while (0)
304 #define STATS_INC_NODEFREES(x) do { } while (0)
305 #define STATS_INC_ACOVERFLOW(x) do { } while (0)
306 #define STATS_SET_FREEABLE(x, i) do { } while (0)
307 #define STATS_INC_ALLOCHIT(x) do { } while (0)
308 #define STATS_INC_ALLOCMISS(x) do { } while (0)
309 #define STATS_INC_FREEHIT(x) do { } while (0)
310 #define STATS_INC_FREEMISS(x) do { } while (0)
316 * memory layout of objects:
318 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that
319 * the end of an object is aligned with the end of the real
320 * allocation. Catches writes behind the end of the allocation.
321 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
323 * cachep->obj_offset: The real object.
324 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
325 * cachep->size - 1* BYTES_PER_WORD: last caller address
326 * [BYTES_PER_WORD long]
328 static int obj_offset(struct kmem_cache
*cachep
)
330 return cachep
->obj_offset
;
333 static unsigned long long *dbg_redzone1(struct kmem_cache
*cachep
, void *objp
)
335 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
336 return (unsigned long long *) (objp
+ obj_offset(cachep
) -
337 sizeof(unsigned long long));
340 static unsigned long long *dbg_redzone2(struct kmem_cache
*cachep
, void *objp
)
342 BUG_ON(!(cachep
->flags
& SLAB_RED_ZONE
));
343 if (cachep
->flags
& SLAB_STORE_USER
)
344 return (unsigned long long *)(objp
+ cachep
->size
-
345 sizeof(unsigned long long) -
347 return (unsigned long long *) (objp
+ cachep
->size
-
348 sizeof(unsigned long long));
351 static void **dbg_userword(struct kmem_cache
*cachep
, void *objp
)
353 BUG_ON(!(cachep
->flags
& SLAB_STORE_USER
));
354 return (void **)(objp
+ cachep
->size
- BYTES_PER_WORD
);
359 #define obj_offset(x) 0
360 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
361 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
362 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
367 * Do not go above this order unless 0 objects fit into the slab or
368 * overridden on the command line.
370 #define SLAB_MAX_ORDER_HI 1
371 #define SLAB_MAX_ORDER_LO 0
372 static int slab_max_order
= SLAB_MAX_ORDER_LO
;
373 static bool slab_max_order_set __initdata
;
375 static inline void *index_to_obj(struct kmem_cache
*cache
,
376 const struct slab
*slab
, unsigned int idx
)
378 return slab
->s_mem
+ cache
->size
* idx
;
381 #define BOOT_CPUCACHE_ENTRIES 1
382 /* internal cache of cache description objs */
383 static struct kmem_cache kmem_cache_boot
= {
385 .limit
= BOOT_CPUCACHE_ENTRIES
,
387 .size
= sizeof(struct kmem_cache
),
388 .name
= "kmem_cache",
391 static DEFINE_PER_CPU(struct delayed_work
, slab_reap_work
);
393 static inline struct array_cache
*cpu_cache_get(struct kmem_cache
*cachep
)
395 return this_cpu_ptr(cachep
->cpu_cache
);
399 * Calculate the number of objects and left-over bytes for a given buffer size.
401 static unsigned int cache_estimate(unsigned long gfporder
, size_t buffer_size
,
402 slab_flags_t flags
, size_t *left_over
)
405 size_t slab_size
= PAGE_SIZE
<< gfporder
;
408 * The slab management structure can be either off the slab or
409 * on it. For the latter case, the memory allocated for a
412 * - @buffer_size bytes for each object
413 * - One freelist_idx_t for each object
415 * We don't need to consider alignment of freelist because
416 * freelist will be at the end of slab page. The objects will be
417 * at the correct alignment.
419 * If the slab management structure is off the slab, then the
420 * alignment will already be calculated into the size. Because
421 * the slabs are all pages aligned, the objects will be at the
422 * correct alignment when allocated.
424 if (flags
& (CFLGS_OBJFREELIST_SLAB
| CFLGS_OFF_SLAB
)) {
425 num
= slab_size
/ buffer_size
;
426 *left_over
= slab_size
% buffer_size
;
428 num
= slab_size
/ (buffer_size
+ sizeof(freelist_idx_t
));
429 *left_over
= slab_size
%
430 (buffer_size
+ sizeof(freelist_idx_t
));
437 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
439 static void __slab_error(const char *function
, struct kmem_cache
*cachep
,
442 pr_err("slab error in %s(): cache `%s': %s\n",
443 function
, cachep
->name
, msg
);
445 add_taint(TAINT_BAD_PAGE
, LOCKDEP_NOW_UNRELIABLE
);
450 * By default on NUMA we use alien caches to stage the freeing of
451 * objects allocated from other nodes. This causes massive memory
452 * inefficiencies when using fake NUMA setup to split memory into a
453 * large number of small nodes, so it can be disabled on the command
457 static int use_alien_caches __read_mostly
= 1;
458 static int __init
noaliencache_setup(char *s
)
460 use_alien_caches
= 0;
463 __setup("noaliencache", noaliencache_setup
);
465 static int __init
slab_max_order_setup(char *str
)
467 get_option(&str
, &slab_max_order
);
468 slab_max_order
= slab_max_order
< 0 ? 0 :
469 min(slab_max_order
, MAX_ORDER
- 1);
470 slab_max_order_set
= true;
474 __setup("slab_max_order=", slab_max_order_setup
);
478 * Special reaping functions for NUMA systems called from cache_reap().
479 * These take care of doing round robin flushing of alien caches (containing
480 * objects freed on different nodes from which they were allocated) and the
481 * flushing of remote pcps by calling drain_node_pages.
483 static DEFINE_PER_CPU(unsigned long, slab_reap_node
);
485 static void init_reap_node(int cpu
)
487 per_cpu(slab_reap_node
, cpu
) = next_node_in(cpu_to_mem(cpu
),
491 static void next_reap_node(void)
493 int node
= __this_cpu_read(slab_reap_node
);
495 node
= next_node_in(node
, node_online_map
);
496 __this_cpu_write(slab_reap_node
, node
);
500 #define init_reap_node(cpu) do { } while (0)
501 #define next_reap_node(void) do { } while (0)
505 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz
506 * via the workqueue/eventd.
507 * Add the CPU number into the expiration time to minimize the possibility of
508 * the CPUs getting into lockstep and contending for the global cache chain
511 static void start_cpu_timer(int cpu
)
513 struct delayed_work
*reap_work
= &per_cpu(slab_reap_work
, cpu
);
515 if (reap_work
->work
.func
== NULL
) {
517 INIT_DEFERRABLE_WORK(reap_work
, cache_reap
);
518 schedule_delayed_work_on(cpu
, reap_work
,
519 __round_jiffies_relative(HZ
, cpu
));
523 static void init_arraycache(struct array_cache
*ac
, int limit
, int batch
)
528 ac
->batchcount
= batch
;
533 static struct array_cache
*alloc_arraycache(int node
, int entries
,
534 int batchcount
, gfp_t gfp
)
536 size_t memsize
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
537 struct array_cache
*ac
= NULL
;
539 ac
= kmalloc_node(memsize
, gfp
, node
);
541 * The array_cache structures contain pointers to free object.
542 * However, when such objects are allocated or transferred to another
543 * cache the pointers are not cleared and they could be counted as
544 * valid references during a kmemleak scan. Therefore, kmemleak must
545 * not scan such objects.
547 kmemleak_no_scan(ac
);
548 init_arraycache(ac
, entries
, batchcount
);
552 static noinline
void cache_free_pfmemalloc(struct kmem_cache
*cachep
,
553 struct slab
*slab
, void *objp
)
555 struct kmem_cache_node
*n
;
559 slab_node
= slab_nid(slab
);
560 n
= get_node(cachep
, slab_node
);
562 spin_lock(&n
->list_lock
);
563 free_block(cachep
, &objp
, 1, slab_node
, &list
);
564 spin_unlock(&n
->list_lock
);
566 slabs_destroy(cachep
, &list
);
570 * Transfer objects in one arraycache to another.
571 * Locking must be handled by the caller.
573 * Return the number of entries transferred.
575 static int transfer_objects(struct array_cache
*to
,
576 struct array_cache
*from
, unsigned int max
)
578 /* Figure out how many entries to transfer */
579 int nr
= min3(from
->avail
, max
, to
->limit
- to
->avail
);
584 memcpy(to
->entry
+ to
->avail
, from
->entry
+ from
->avail
- nr
,
592 /* &alien->lock must be held by alien callers. */
593 static __always_inline
void __free_one(struct array_cache
*ac
, void *objp
)
595 /* Avoid trivial double-free. */
596 if (IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED
) &&
597 WARN_ON_ONCE(ac
->avail
> 0 && ac
->entry
[ac
->avail
- 1] == objp
))
599 ac
->entry
[ac
->avail
++] = objp
;
604 #define drain_alien_cache(cachep, alien) do { } while (0)
605 #define reap_alien(cachep, n) do { } while (0)
607 static inline struct alien_cache
**alloc_alien_cache(int node
,
608 int limit
, gfp_t gfp
)
613 static inline void free_alien_cache(struct alien_cache
**ac_ptr
)
617 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
622 static inline gfp_t
gfp_exact_node(gfp_t flags
)
624 return flags
& ~__GFP_NOFAIL
;
627 #else /* CONFIG_NUMA */
629 static struct alien_cache
*__alloc_alien_cache(int node
, int entries
,
630 int batch
, gfp_t gfp
)
632 size_t memsize
= sizeof(void *) * entries
+ sizeof(struct alien_cache
);
633 struct alien_cache
*alc
= NULL
;
635 alc
= kmalloc_node(memsize
, gfp
, node
);
637 kmemleak_no_scan(alc
);
638 init_arraycache(&alc
->ac
, entries
, batch
);
639 spin_lock_init(&alc
->lock
);
644 static struct alien_cache
**alloc_alien_cache(int node
, int limit
, gfp_t gfp
)
646 struct alien_cache
**alc_ptr
;
651 alc_ptr
= kcalloc_node(nr_node_ids
, sizeof(void *), gfp
, node
);
656 if (i
== node
|| !node_online(i
))
658 alc_ptr
[i
] = __alloc_alien_cache(node
, limit
, 0xbaadf00d, gfp
);
660 for (i
--; i
>= 0; i
--)
669 static void free_alien_cache(struct alien_cache
**alc_ptr
)
680 static void __drain_alien_cache(struct kmem_cache
*cachep
,
681 struct array_cache
*ac
, int node
,
682 struct list_head
*list
)
684 struct kmem_cache_node
*n
= get_node(cachep
, node
);
687 spin_lock(&n
->list_lock
);
689 * Stuff objects into the remote nodes shared array first.
690 * That way we could avoid the overhead of putting the objects
691 * into the free lists and getting them back later.
694 transfer_objects(n
->shared
, ac
, ac
->limit
);
696 free_block(cachep
, ac
->entry
, ac
->avail
, node
, list
);
698 spin_unlock(&n
->list_lock
);
703 * Called from cache_reap() to regularly drain alien caches round robin.
705 static void reap_alien(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
)
707 int node
= __this_cpu_read(slab_reap_node
);
710 struct alien_cache
*alc
= n
->alien
[node
];
711 struct array_cache
*ac
;
715 if (ac
->avail
&& spin_trylock_irq(&alc
->lock
)) {
718 __drain_alien_cache(cachep
, ac
, node
, &list
);
719 spin_unlock_irq(&alc
->lock
);
720 slabs_destroy(cachep
, &list
);
726 static void drain_alien_cache(struct kmem_cache
*cachep
,
727 struct alien_cache
**alien
)
730 struct alien_cache
*alc
;
731 struct array_cache
*ac
;
734 for_each_online_node(i
) {
740 spin_lock_irqsave(&alc
->lock
, flags
);
741 __drain_alien_cache(cachep
, ac
, i
, &list
);
742 spin_unlock_irqrestore(&alc
->lock
, flags
);
743 slabs_destroy(cachep
, &list
);
748 static int __cache_free_alien(struct kmem_cache
*cachep
, void *objp
,
749 int node
, int slab_node
)
751 struct kmem_cache_node
*n
;
752 struct alien_cache
*alien
= NULL
;
753 struct array_cache
*ac
;
756 n
= get_node(cachep
, node
);
757 STATS_INC_NODEFREES(cachep
);
758 if (n
->alien
&& n
->alien
[slab_node
]) {
759 alien
= n
->alien
[slab_node
];
761 spin_lock(&alien
->lock
);
762 if (unlikely(ac
->avail
== ac
->limit
)) {
763 STATS_INC_ACOVERFLOW(cachep
);
764 __drain_alien_cache(cachep
, ac
, slab_node
, &list
);
766 __free_one(ac
, objp
);
767 spin_unlock(&alien
->lock
);
768 slabs_destroy(cachep
, &list
);
770 n
= get_node(cachep
, slab_node
);
771 spin_lock(&n
->list_lock
);
772 free_block(cachep
, &objp
, 1, slab_node
, &list
);
773 spin_unlock(&n
->list_lock
);
774 slabs_destroy(cachep
, &list
);
779 static inline int cache_free_alien(struct kmem_cache
*cachep
, void *objp
)
781 int slab_node
= slab_nid(virt_to_slab(objp
));
782 int node
= numa_mem_id();
784 * Make sure we are not freeing an object from another node to the array
787 if (likely(node
== slab_node
))
790 return __cache_free_alien(cachep
, objp
, node
, slab_node
);
794 * Construct gfp mask to allocate from a specific node but do not reclaim or
795 * warn about failures.
797 static inline gfp_t
gfp_exact_node(gfp_t flags
)
799 return (flags
| __GFP_THISNODE
| __GFP_NOWARN
) & ~(__GFP_RECLAIM
|__GFP_NOFAIL
);
803 static int init_cache_node(struct kmem_cache
*cachep
, int node
, gfp_t gfp
)
805 struct kmem_cache_node
*n
;
808 * Set up the kmem_cache_node for cpu before we can
809 * begin anything. Make sure some other cpu on this
810 * node has not already allocated this
812 n
= get_node(cachep
, node
);
814 spin_lock_irq(&n
->list_lock
);
815 n
->free_limit
= (1 + nr_cpus_node(node
)) * cachep
->batchcount
+
817 spin_unlock_irq(&n
->list_lock
);
822 n
= kmalloc_node(sizeof(struct kmem_cache_node
), gfp
, node
);
826 kmem_cache_node_init(n
);
827 n
->next_reap
= jiffies
+ REAPTIMEOUT_NODE
+
828 ((unsigned long)cachep
) % REAPTIMEOUT_NODE
;
831 (1 + nr_cpus_node(node
)) * cachep
->batchcount
+ cachep
->num
;
834 * The kmem_cache_nodes don't come and go as CPUs
835 * come and go. slab_mutex provides sufficient
838 cachep
->node
[node
] = n
;
843 #if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
845 * Allocates and initializes node for a node on each slab cache, used for
846 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
847 * will be allocated off-node since memory is not yet online for the new node.
848 * When hotplugging memory or a cpu, existing nodes are not replaced if
851 * Must hold slab_mutex.
853 static int init_cache_node_node(int node
)
856 struct kmem_cache
*cachep
;
858 list_for_each_entry(cachep
, &slab_caches
, list
) {
859 ret
= init_cache_node(cachep
, node
, GFP_KERNEL
);
868 static int setup_kmem_cache_node(struct kmem_cache
*cachep
,
869 int node
, gfp_t gfp
, bool force_change
)
872 struct kmem_cache_node
*n
;
873 struct array_cache
*old_shared
= NULL
;
874 struct array_cache
*new_shared
= NULL
;
875 struct alien_cache
**new_alien
= NULL
;
878 if (use_alien_caches
) {
879 new_alien
= alloc_alien_cache(node
, cachep
->limit
, gfp
);
884 if (cachep
->shared
) {
885 new_shared
= alloc_arraycache(node
,
886 cachep
->shared
* cachep
->batchcount
, 0xbaadf00d, gfp
);
891 ret
= init_cache_node(cachep
, node
, gfp
);
895 n
= get_node(cachep
, node
);
896 spin_lock_irq(&n
->list_lock
);
897 if (n
->shared
&& force_change
) {
898 free_block(cachep
, n
->shared
->entry
,
899 n
->shared
->avail
, node
, &list
);
900 n
->shared
->avail
= 0;
903 if (!n
->shared
|| force_change
) {
904 old_shared
= n
->shared
;
905 n
->shared
= new_shared
;
910 n
->alien
= new_alien
;
914 spin_unlock_irq(&n
->list_lock
);
915 slabs_destroy(cachep
, &list
);
918 * To protect lockless access to n->shared during irq disabled context.
919 * If n->shared isn't NULL in irq disabled context, accessing to it is
920 * guaranteed to be valid until irq is re-enabled, because it will be
921 * freed after synchronize_rcu().
923 if (old_shared
&& force_change
)
929 free_alien_cache(new_alien
);
936 static void cpuup_canceled(long cpu
)
938 struct kmem_cache
*cachep
;
939 struct kmem_cache_node
*n
= NULL
;
940 int node
= cpu_to_mem(cpu
);
941 const struct cpumask
*mask
= cpumask_of_node(node
);
943 list_for_each_entry(cachep
, &slab_caches
, list
) {
944 struct array_cache
*nc
;
945 struct array_cache
*shared
;
946 struct alien_cache
**alien
;
949 n
= get_node(cachep
, node
);
953 spin_lock_irq(&n
->list_lock
);
955 /* Free limit for this kmem_cache_node */
956 n
->free_limit
-= cachep
->batchcount
;
958 /* cpu is dead; no one can alloc from it. */
959 nc
= per_cpu_ptr(cachep
->cpu_cache
, cpu
);
960 free_block(cachep
, nc
->entry
, nc
->avail
, node
, &list
);
963 if (!cpumask_empty(mask
)) {
964 spin_unlock_irq(&n
->list_lock
);
970 free_block(cachep
, shared
->entry
,
971 shared
->avail
, node
, &list
);
978 spin_unlock_irq(&n
->list_lock
);
982 drain_alien_cache(cachep
, alien
);
983 free_alien_cache(alien
);
987 slabs_destroy(cachep
, &list
);
990 * In the previous loop, all the objects were freed to
991 * the respective cache's slabs, now we can go ahead and
992 * shrink each nodelist to its limit.
994 list_for_each_entry(cachep
, &slab_caches
, list
) {
995 n
= get_node(cachep
, node
);
998 drain_freelist(cachep
, n
, INT_MAX
);
1002 static int cpuup_prepare(long cpu
)
1004 struct kmem_cache
*cachep
;
1005 int node
= cpu_to_mem(cpu
);
1009 * We need to do this right in the beginning since
1010 * alloc_arraycache's are going to use this list.
1011 * kmalloc_node allows us to add the slab to the right
1012 * kmem_cache_node and not this cpu's kmem_cache_node
1014 err
= init_cache_node_node(node
);
1019 * Now we can go ahead with allocating the shared arrays and
1022 list_for_each_entry(cachep
, &slab_caches
, list
) {
1023 err
= setup_kmem_cache_node(cachep
, node
, GFP_KERNEL
, false);
1030 cpuup_canceled(cpu
);
1034 int slab_prepare_cpu(unsigned int cpu
)
1038 mutex_lock(&slab_mutex
);
1039 err
= cpuup_prepare(cpu
);
1040 mutex_unlock(&slab_mutex
);
1045 * This is called for a failed online attempt and for a successful
1048 * Even if all the cpus of a node are down, we don't free the
1049 * kmem_cache_node of any cache. This is to avoid a race between cpu_down, and
1050 * a kmalloc allocation from another cpu for memory from the node of
1051 * the cpu going down. The kmem_cache_node structure is usually allocated from
1052 * kmem_cache_create() and gets destroyed at kmem_cache_destroy().
1054 int slab_dead_cpu(unsigned int cpu
)
1056 mutex_lock(&slab_mutex
);
1057 cpuup_canceled(cpu
);
1058 mutex_unlock(&slab_mutex
);
1063 static int slab_online_cpu(unsigned int cpu
)
1065 start_cpu_timer(cpu
);
1069 static int slab_offline_cpu(unsigned int cpu
)
1072 * Shutdown cache reaper. Note that the slab_mutex is held so
1073 * that if cache_reap() is invoked it cannot do anything
1074 * expensive but will only modify reap_work and reschedule the
1077 cancel_delayed_work_sync(&per_cpu(slab_reap_work
, cpu
));
1078 /* Now the cache_reaper is guaranteed to be not running. */
1079 per_cpu(slab_reap_work
, cpu
).work
.func
= NULL
;
1083 #if defined(CONFIG_NUMA)
1085 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1086 * Returns -EBUSY if all objects cannot be drained so that the node is not
1089 * Must hold slab_mutex.
1091 static int __meminit
drain_cache_node_node(int node
)
1093 struct kmem_cache
*cachep
;
1096 list_for_each_entry(cachep
, &slab_caches
, list
) {
1097 struct kmem_cache_node
*n
;
1099 n
= get_node(cachep
, node
);
1103 drain_freelist(cachep
, n
, INT_MAX
);
1105 if (!list_empty(&n
->slabs_full
) ||
1106 !list_empty(&n
->slabs_partial
)) {
1114 static int __meminit
slab_memory_callback(struct notifier_block
*self
,
1115 unsigned long action
, void *arg
)
1117 struct memory_notify
*mnb
= arg
;
1121 nid
= mnb
->status_change_nid
;
1126 case MEM_GOING_ONLINE
:
1127 mutex_lock(&slab_mutex
);
1128 ret
= init_cache_node_node(nid
);
1129 mutex_unlock(&slab_mutex
);
1131 case MEM_GOING_OFFLINE
:
1132 mutex_lock(&slab_mutex
);
1133 ret
= drain_cache_node_node(nid
);
1134 mutex_unlock(&slab_mutex
);
1138 case MEM_CANCEL_ONLINE
:
1139 case MEM_CANCEL_OFFLINE
:
1143 return notifier_from_errno(ret
);
1145 #endif /* CONFIG_NUMA */
1148 * swap the static kmem_cache_node with kmalloced memory
1150 static void __init
init_list(struct kmem_cache
*cachep
, struct kmem_cache_node
*list
,
1153 struct kmem_cache_node
*ptr
;
1155 ptr
= kmalloc_node(sizeof(struct kmem_cache_node
), GFP_NOWAIT
, nodeid
);
1158 memcpy(ptr
, list
, sizeof(struct kmem_cache_node
));
1160 * Do not assume that spinlocks can be initialized via memcpy:
1162 spin_lock_init(&ptr
->list_lock
);
1164 MAKE_ALL_LISTS(cachep
, ptr
, nodeid
);
1165 cachep
->node
[nodeid
] = ptr
;
1169 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1170 * size of kmem_cache_node.
1172 static void __init
set_up_node(struct kmem_cache
*cachep
, int index
)
1176 for_each_online_node(node
) {
1177 cachep
->node
[node
] = &init_kmem_cache_node
[index
+ node
];
1178 cachep
->node
[node
]->next_reap
= jiffies
+
1180 ((unsigned long)cachep
) % REAPTIMEOUT_NODE
;
1185 * Initialisation. Called after the page allocator have been initialised and
1186 * before smp_init().
1188 void __init
kmem_cache_init(void)
1192 kmem_cache
= &kmem_cache_boot
;
1194 if (!IS_ENABLED(CONFIG_NUMA
) || num_possible_nodes() == 1)
1195 use_alien_caches
= 0;
1197 for (i
= 0; i
< NUM_INIT_LISTS
; i
++)
1198 kmem_cache_node_init(&init_kmem_cache_node
[i
]);
1201 * Fragmentation resistance on low memory - only use bigger
1202 * page orders on machines with more than 32MB of memory if
1203 * not overridden on the command line.
1205 if (!slab_max_order_set
&& totalram_pages() > (32 << 20) >> PAGE_SHIFT
)
1206 slab_max_order
= SLAB_MAX_ORDER_HI
;
1208 /* Bootstrap is tricky, because several objects are allocated
1209 * from caches that do not exist yet:
1210 * 1) initialize the kmem_cache cache: it contains the struct
1211 * kmem_cache structures of all caches, except kmem_cache itself:
1212 * kmem_cache is statically allocated.
1213 * Initially an __init data area is used for the head array and the
1214 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1215 * array at the end of the bootstrap.
1216 * 2) Create the first kmalloc cache.
1217 * The struct kmem_cache for the new cache is allocated normally.
1218 * An __init data area is used for the head array.
1219 * 3) Create the remaining kmalloc caches, with minimally sized
1221 * 4) Replace the __init data head arrays for kmem_cache and the first
1222 * kmalloc cache with kmalloc allocated arrays.
1223 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1224 * the other cache's with kmalloc allocated memory.
1225 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1228 /* 1) create the kmem_cache */
1231 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1233 create_boot_cache(kmem_cache
, "kmem_cache",
1234 offsetof(struct kmem_cache
, node
) +
1235 nr_node_ids
* sizeof(struct kmem_cache_node
*),
1236 SLAB_HWCACHE_ALIGN
, 0, 0);
1237 list_add(&kmem_cache
->list
, &slab_caches
);
1238 slab_state
= PARTIAL
;
1241 * Initialize the caches that provide memory for the kmem_cache_node
1242 * structures first. Without this, further allocations will bug.
1244 kmalloc_caches
[KMALLOC_NORMAL
][INDEX_NODE
] = create_kmalloc_cache(
1245 kmalloc_info
[INDEX_NODE
].name
[KMALLOC_NORMAL
],
1246 kmalloc_info
[INDEX_NODE
].size
,
1247 ARCH_KMALLOC_FLAGS
, 0,
1248 kmalloc_info
[INDEX_NODE
].size
);
1249 slab_state
= PARTIAL_NODE
;
1250 setup_kmalloc_cache_index_table();
1252 slab_early_init
= 0;
1254 /* 5) Replace the bootstrap kmem_cache_node */
1258 for_each_online_node(nid
) {
1259 init_list(kmem_cache
, &init_kmem_cache_node
[CACHE_CACHE
+ nid
], nid
);
1261 init_list(kmalloc_caches
[KMALLOC_NORMAL
][INDEX_NODE
],
1262 &init_kmem_cache_node
[SIZE_NODE
+ nid
], nid
);
1266 create_kmalloc_caches(ARCH_KMALLOC_FLAGS
);
1269 void __init
kmem_cache_init_late(void)
1271 struct kmem_cache
*cachep
;
1273 /* 6) resize the head arrays to their final sizes */
1274 mutex_lock(&slab_mutex
);
1275 list_for_each_entry(cachep
, &slab_caches
, list
)
1276 if (enable_cpucache(cachep
, GFP_NOWAIT
))
1278 mutex_unlock(&slab_mutex
);
1285 * Register a memory hotplug callback that initializes and frees
1288 hotplug_memory_notifier(slab_memory_callback
, SLAB_CALLBACK_PRI
);
1292 * The reap timers are started later, with a module init call: That part
1293 * of the kernel is not yet operational.
1297 static int __init
cpucache_init(void)
1302 * Register the timers that return unneeded pages to the page allocator
1304 ret
= cpuhp_setup_state(CPUHP_AP_ONLINE_DYN
, "SLAB online",
1305 slab_online_cpu
, slab_offline_cpu
);
1310 __initcall(cpucache_init
);
1312 static noinline
void
1313 slab_out_of_memory(struct kmem_cache
*cachep
, gfp_t gfpflags
, int nodeid
)
1316 struct kmem_cache_node
*n
;
1317 unsigned long flags
;
1319 static DEFINE_RATELIMIT_STATE(slab_oom_rs
, DEFAULT_RATELIMIT_INTERVAL
,
1320 DEFAULT_RATELIMIT_BURST
);
1322 if ((gfpflags
& __GFP_NOWARN
) || !__ratelimit(&slab_oom_rs
))
1325 pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
1326 nodeid
, gfpflags
, &gfpflags
);
1327 pr_warn(" cache: %s, object size: %d, order: %d\n",
1328 cachep
->name
, cachep
->size
, cachep
->gfporder
);
1330 for_each_kmem_cache_node(cachep
, node
, n
) {
1331 unsigned long total_slabs
, free_slabs
, free_objs
;
1333 spin_lock_irqsave(&n
->list_lock
, flags
);
1334 total_slabs
= n
->total_slabs
;
1335 free_slabs
= n
->free_slabs
;
1336 free_objs
= n
->free_objects
;
1337 spin_unlock_irqrestore(&n
->list_lock
, flags
);
1339 pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld\n",
1340 node
, total_slabs
- free_slabs
, total_slabs
,
1341 (total_slabs
* cachep
->num
) - free_objs
,
1342 total_slabs
* cachep
->num
);
1348 * Interface to system's page allocator. No need to hold the
1349 * kmem_cache_node ->list_lock.
1351 * If we requested dmaable memory, we will get it. Even if we
1352 * did not request dmaable memory, we might get it, but that
1353 * would be relatively rare and ignorable.
1355 static struct slab
*kmem_getpages(struct kmem_cache
*cachep
, gfp_t flags
,
1358 struct folio
*folio
;
1361 flags
|= cachep
->allocflags
;
1363 folio
= (struct folio
*) __alloc_pages_node(nodeid
, flags
, cachep
->gfporder
);
1365 slab_out_of_memory(cachep
, flags
, nodeid
);
1369 slab
= folio_slab(folio
);
1371 account_slab(slab
, cachep
->gfporder
, cachep
, flags
);
1372 __folio_set_slab(folio
);
1373 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1374 if (sk_memalloc_socks() && page_is_pfmemalloc(folio_page(folio
, 0)))
1375 slab_set_pfmemalloc(slab
);
1381 * Interface to system's page release.
1383 static void kmem_freepages(struct kmem_cache
*cachep
, struct slab
*slab
)
1385 int order
= cachep
->gfporder
;
1386 struct folio
*folio
= slab_folio(slab
);
1388 BUG_ON(!folio_test_slab(folio
));
1389 __slab_clear_pfmemalloc(slab
);
1390 __folio_clear_slab(folio
);
1391 page_mapcount_reset(folio_page(folio
, 0));
1392 folio
->mapping
= NULL
;
1394 if (current
->reclaim_state
)
1395 current
->reclaim_state
->reclaimed_slab
+= 1 << order
;
1396 unaccount_slab(slab
, order
, cachep
);
1397 __free_pages(folio_page(folio
, 0), order
);
1400 static void kmem_rcu_free(struct rcu_head
*head
)
1402 struct kmem_cache
*cachep
;
1405 slab
= container_of(head
, struct slab
, rcu_head
);
1406 cachep
= slab
->slab_cache
;
1408 kmem_freepages(cachep
, slab
);
1412 static bool is_debug_pagealloc_cache(struct kmem_cache
*cachep
)
1414 if (debug_pagealloc_enabled_static() && OFF_SLAB(cachep
) &&
1415 (cachep
->size
% PAGE_SIZE
) == 0)
1421 #ifdef CONFIG_DEBUG_PAGEALLOC
1422 static void slab_kernel_map(struct kmem_cache
*cachep
, void *objp
, int map
)
1424 if (!is_debug_pagealloc_cache(cachep
))
1427 __kernel_map_pages(virt_to_page(objp
), cachep
->size
/ PAGE_SIZE
, map
);
1431 static inline void slab_kernel_map(struct kmem_cache
*cachep
, void *objp
,
1436 static void poison_obj(struct kmem_cache
*cachep
, void *addr
, unsigned char val
)
1438 int size
= cachep
->object_size
;
1439 addr
= &((char *)addr
)[obj_offset(cachep
)];
1441 memset(addr
, val
, size
);
1442 *(unsigned char *)(addr
+ size
- 1) = POISON_END
;
1445 static void dump_line(char *data
, int offset
, int limit
)
1448 unsigned char error
= 0;
1451 pr_err("%03x: ", offset
);
1452 for (i
= 0; i
< limit
; i
++) {
1453 if (data
[offset
+ i
] != POISON_FREE
) {
1454 error
= data
[offset
+ i
];
1458 print_hex_dump(KERN_CONT
, "", 0, 16, 1,
1459 &data
[offset
], limit
, 1);
1461 if (bad_count
== 1) {
1462 error
^= POISON_FREE
;
1463 if (!(error
& (error
- 1))) {
1464 pr_err("Single bit error detected. Probably bad RAM.\n");
1466 pr_err("Run memtest86+ or a similar memory test tool.\n");
1468 pr_err("Run a memory test tool.\n");
1477 static void print_objinfo(struct kmem_cache
*cachep
, void *objp
, int lines
)
1482 if (cachep
->flags
& SLAB_RED_ZONE
) {
1483 pr_err("Redzone: 0x%llx/0x%llx\n",
1484 *dbg_redzone1(cachep
, objp
),
1485 *dbg_redzone2(cachep
, objp
));
1488 if (cachep
->flags
& SLAB_STORE_USER
)
1489 pr_err("Last user: (%pSR)\n", *dbg_userword(cachep
, objp
));
1490 realobj
= (char *)objp
+ obj_offset(cachep
);
1491 size
= cachep
->object_size
;
1492 for (i
= 0; i
< size
&& lines
; i
+= 16, lines
--) {
1495 if (i
+ limit
> size
)
1497 dump_line(realobj
, i
, limit
);
1501 static void check_poison_obj(struct kmem_cache
*cachep
, void *objp
)
1507 if (is_debug_pagealloc_cache(cachep
))
1510 realobj
= (char *)objp
+ obj_offset(cachep
);
1511 size
= cachep
->object_size
;
1513 for (i
= 0; i
< size
; i
++) {
1514 char exp
= POISON_FREE
;
1517 if (realobj
[i
] != exp
) {
1522 pr_err("Slab corruption (%s): %s start=%px, len=%d\n",
1523 print_tainted(), cachep
->name
,
1525 print_objinfo(cachep
, objp
, 0);
1527 /* Hexdump the affected line */
1530 if (i
+ limit
> size
)
1532 dump_line(realobj
, i
, limit
);
1535 /* Limit to 5 lines */
1541 /* Print some data about the neighboring objects, if they
1544 struct slab
*slab
= virt_to_slab(objp
);
1547 objnr
= obj_to_index(cachep
, slab
, objp
);
1549 objp
= index_to_obj(cachep
, slab
, objnr
- 1);
1550 realobj
= (char *)objp
+ obj_offset(cachep
);
1551 pr_err("Prev obj: start=%px, len=%d\n", realobj
, size
);
1552 print_objinfo(cachep
, objp
, 2);
1554 if (objnr
+ 1 < cachep
->num
) {
1555 objp
= index_to_obj(cachep
, slab
, objnr
+ 1);
1556 realobj
= (char *)objp
+ obj_offset(cachep
);
1557 pr_err("Next obj: start=%px, len=%d\n", realobj
, size
);
1558 print_objinfo(cachep
, objp
, 2);
1565 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
,
1570 if (OBJFREELIST_SLAB(cachep
) && cachep
->flags
& SLAB_POISON
) {
1571 poison_obj(cachep
, slab
->freelist
- obj_offset(cachep
),
1575 for (i
= 0; i
< cachep
->num
; i
++) {
1576 void *objp
= index_to_obj(cachep
, slab
, i
);
1578 if (cachep
->flags
& SLAB_POISON
) {
1579 check_poison_obj(cachep
, objp
);
1580 slab_kernel_map(cachep
, objp
, 1);
1582 if (cachep
->flags
& SLAB_RED_ZONE
) {
1583 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
1584 slab_error(cachep
, "start of a freed object was overwritten");
1585 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
1586 slab_error(cachep
, "end of a freed object was overwritten");
1591 static void slab_destroy_debugcheck(struct kmem_cache
*cachep
,
1598 * slab_destroy - destroy and release all objects in a slab
1599 * @cachep: cache pointer being destroyed
1600 * @slab: slab being destroyed
1602 * Destroy all the objs in a slab, and release the mem back to the system.
1603 * Before calling the slab must have been unlinked from the cache. The
1604 * kmem_cache_node ->list_lock is not held/needed.
1606 static void slab_destroy(struct kmem_cache
*cachep
, struct slab
*slab
)
1610 freelist
= slab
->freelist
;
1611 slab_destroy_debugcheck(cachep
, slab
);
1612 if (unlikely(cachep
->flags
& SLAB_TYPESAFE_BY_RCU
))
1613 call_rcu(&slab
->rcu_head
, kmem_rcu_free
);
1615 kmem_freepages(cachep
, slab
);
1618 * From now on, we don't use freelist
1619 * although actual page can be freed in rcu context
1621 if (OFF_SLAB(cachep
))
1622 kmem_cache_free(cachep
->freelist_cache
, freelist
);
1626 * Update the size of the caches before calling slabs_destroy as it may
1627 * recursively call kfree.
1629 static void slabs_destroy(struct kmem_cache
*cachep
, struct list_head
*list
)
1631 struct slab
*slab
, *n
;
1633 list_for_each_entry_safe(slab
, n
, list
, slab_list
) {
1634 list_del(&slab
->slab_list
);
1635 slab_destroy(cachep
, slab
);
1640 * calculate_slab_order - calculate size (page order) of slabs
1641 * @cachep: pointer to the cache that is being created
1642 * @size: size of objects to be created in this cache.
1643 * @flags: slab allocation flags
1645 * Also calculates the number of objects per slab.
1647 * This could be made much more intelligent. For now, try to avoid using
1648 * high order pages for slabs. When the gfp() functions are more friendly
1649 * towards high-order requests, this should be changed.
1651 * Return: number of left-over bytes in a slab
1653 static size_t calculate_slab_order(struct kmem_cache
*cachep
,
1654 size_t size
, slab_flags_t flags
)
1656 size_t left_over
= 0;
1659 for (gfporder
= 0; gfporder
<= KMALLOC_MAX_ORDER
; gfporder
++) {
1663 num
= cache_estimate(gfporder
, size
, flags
, &remainder
);
1667 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */
1668 if (num
> SLAB_OBJ_MAX_NUM
)
1671 if (flags
& CFLGS_OFF_SLAB
) {
1672 struct kmem_cache
*freelist_cache
;
1673 size_t freelist_size
;
1675 freelist_size
= num
* sizeof(freelist_idx_t
);
1676 freelist_cache
= kmalloc_slab(freelist_size
, 0u);
1677 if (!freelist_cache
)
1681 * Needed to avoid possible looping condition
1682 * in cache_grow_begin()
1684 if (OFF_SLAB(freelist_cache
))
1687 /* check if off slab has enough benefit */
1688 if (freelist_cache
->size
> cachep
->size
/ 2)
1692 /* Found something acceptable - save it away */
1694 cachep
->gfporder
= gfporder
;
1695 left_over
= remainder
;
1698 * A VFS-reclaimable slab tends to have most allocations
1699 * as GFP_NOFS and we really don't want to have to be allocating
1700 * higher-order pages when we are unable to shrink dcache.
1702 if (flags
& SLAB_RECLAIM_ACCOUNT
)
1706 * Large number of objects is good, but very large slabs are
1707 * currently bad for the gfp()s.
1709 if (gfporder
>= slab_max_order
)
1713 * Acceptable internal fragmentation?
1715 if (left_over
* 8 <= (PAGE_SIZE
<< gfporder
))
1721 static struct array_cache __percpu
*alloc_kmem_cache_cpus(
1722 struct kmem_cache
*cachep
, int entries
, int batchcount
)
1726 struct array_cache __percpu
*cpu_cache
;
1728 size
= sizeof(void *) * entries
+ sizeof(struct array_cache
);
1729 cpu_cache
= __alloc_percpu(size
, sizeof(void *));
1734 for_each_possible_cpu(cpu
) {
1735 init_arraycache(per_cpu_ptr(cpu_cache
, cpu
),
1736 entries
, batchcount
);
1742 static int __ref
setup_cpu_cache(struct kmem_cache
*cachep
, gfp_t gfp
)
1744 if (slab_state
>= FULL
)
1745 return enable_cpucache(cachep
, gfp
);
1747 cachep
->cpu_cache
= alloc_kmem_cache_cpus(cachep
, 1, 1);
1748 if (!cachep
->cpu_cache
)
1751 if (slab_state
== DOWN
) {
1752 /* Creation of first cache (kmem_cache). */
1753 set_up_node(kmem_cache
, CACHE_CACHE
);
1754 } else if (slab_state
== PARTIAL
) {
1755 /* For kmem_cache_node */
1756 set_up_node(cachep
, SIZE_NODE
);
1760 for_each_online_node(node
) {
1761 cachep
->node
[node
] = kmalloc_node(
1762 sizeof(struct kmem_cache_node
), gfp
, node
);
1763 BUG_ON(!cachep
->node
[node
]);
1764 kmem_cache_node_init(cachep
->node
[node
]);
1768 cachep
->node
[numa_mem_id()]->next_reap
=
1769 jiffies
+ REAPTIMEOUT_NODE
+
1770 ((unsigned long)cachep
) % REAPTIMEOUT_NODE
;
1772 cpu_cache_get(cachep
)->avail
= 0;
1773 cpu_cache_get(cachep
)->limit
= BOOT_CPUCACHE_ENTRIES
;
1774 cpu_cache_get(cachep
)->batchcount
= 1;
1775 cpu_cache_get(cachep
)->touched
= 0;
1776 cachep
->batchcount
= 1;
1777 cachep
->limit
= BOOT_CPUCACHE_ENTRIES
;
1781 slab_flags_t
kmem_cache_flags(unsigned int object_size
,
1782 slab_flags_t flags
, const char *name
)
1788 __kmem_cache_alias(const char *name
, unsigned int size
, unsigned int align
,
1789 slab_flags_t flags
, void (*ctor
)(void *))
1791 struct kmem_cache
*cachep
;
1793 cachep
= find_mergeable(size
, align
, flags
, name
, ctor
);
1798 * Adjust the object sizes so that we clear
1799 * the complete object on kzalloc.
1801 cachep
->object_size
= max_t(int, cachep
->object_size
, size
);
1806 static bool set_objfreelist_slab_cache(struct kmem_cache
*cachep
,
1807 size_t size
, slab_flags_t flags
)
1814 * If slab auto-initialization on free is enabled, store the freelist
1815 * off-slab, so that its contents don't end up in one of the allocated
1818 if (unlikely(slab_want_init_on_free(cachep
)))
1821 if (cachep
->ctor
|| flags
& SLAB_TYPESAFE_BY_RCU
)
1824 left
= calculate_slab_order(cachep
, size
,
1825 flags
| CFLGS_OBJFREELIST_SLAB
);
1829 if (cachep
->num
* sizeof(freelist_idx_t
) > cachep
->object_size
)
1832 cachep
->colour
= left
/ cachep
->colour_off
;
1837 static bool set_off_slab_cache(struct kmem_cache
*cachep
,
1838 size_t size
, slab_flags_t flags
)
1845 * Always use on-slab management when SLAB_NOLEAKTRACE
1846 * to avoid recursive calls into kmemleak.
1848 if (flags
& SLAB_NOLEAKTRACE
)
1852 * Size is large, assume best to place the slab management obj
1853 * off-slab (should allow better packing of objs).
1855 left
= calculate_slab_order(cachep
, size
, flags
| CFLGS_OFF_SLAB
);
1860 * If the slab has been placed off-slab, and we have enough space then
1861 * move it on-slab. This is at the expense of any extra colouring.
1863 if (left
>= cachep
->num
* sizeof(freelist_idx_t
))
1866 cachep
->colour
= left
/ cachep
->colour_off
;
1871 static bool set_on_slab_cache(struct kmem_cache
*cachep
,
1872 size_t size
, slab_flags_t flags
)
1878 left
= calculate_slab_order(cachep
, size
, flags
);
1882 cachep
->colour
= left
/ cachep
->colour_off
;
1888 * __kmem_cache_create - Create a cache.
1889 * @cachep: cache management descriptor
1890 * @flags: SLAB flags
1892 * Returns a ptr to the cache on success, NULL on failure.
1893 * Cannot be called within an int, but can be interrupted.
1894 * The @ctor is run when new pages are allocated by the cache.
1898 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1899 * to catch references to uninitialised memory.
1901 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1902 * for buffer overruns.
1904 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1905 * cacheline. This can be beneficial if you're counting cycles as closely
1908 * Return: a pointer to the created cache or %NULL in case of error
1910 int __kmem_cache_create(struct kmem_cache
*cachep
, slab_flags_t flags
)
1912 size_t ralign
= BYTES_PER_WORD
;
1915 unsigned int size
= cachep
->size
;
1920 * Enable redzoning and last user accounting, except for caches with
1921 * large objects, if the increased size would increase the object size
1922 * above the next power of two: caches with object sizes just above a
1923 * power of two have a significant amount of internal fragmentation.
1925 if (size
< 4096 || fls(size
- 1) == fls(size
-1 + REDZONE_ALIGN
+
1926 2 * sizeof(unsigned long long)))
1927 flags
|= SLAB_RED_ZONE
| SLAB_STORE_USER
;
1928 if (!(flags
& SLAB_TYPESAFE_BY_RCU
))
1929 flags
|= SLAB_POISON
;
1934 * Check that size is in terms of words. This is needed to avoid
1935 * unaligned accesses for some archs when redzoning is used, and makes
1936 * sure any on-slab bufctl's are also correctly aligned.
1938 size
= ALIGN(size
, BYTES_PER_WORD
);
1940 if (flags
& SLAB_RED_ZONE
) {
1941 ralign
= REDZONE_ALIGN
;
1942 /* If redzoning, ensure that the second redzone is suitably
1943 * aligned, by adjusting the object size accordingly. */
1944 size
= ALIGN(size
, REDZONE_ALIGN
);
1947 /* 3) caller mandated alignment */
1948 if (ralign
< cachep
->align
) {
1949 ralign
= cachep
->align
;
1951 /* disable debug if necessary */
1952 if (ralign
> __alignof__(unsigned long long))
1953 flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
1957 cachep
->align
= ralign
;
1958 cachep
->colour_off
= cache_line_size();
1959 /* Offset must be a multiple of the alignment. */
1960 if (cachep
->colour_off
< cachep
->align
)
1961 cachep
->colour_off
= cachep
->align
;
1963 if (slab_is_available())
1971 * Both debugging options require word-alignment which is calculated
1974 if (flags
& SLAB_RED_ZONE
) {
1975 /* add space for red zone words */
1976 cachep
->obj_offset
+= sizeof(unsigned long long);
1977 size
+= 2 * sizeof(unsigned long long);
1979 if (flags
& SLAB_STORE_USER
) {
1980 /* user store requires one word storage behind the end of
1981 * the real object. But if the second red zone needs to be
1982 * aligned to 64 bits, we must allow that much space.
1984 if (flags
& SLAB_RED_ZONE
)
1985 size
+= REDZONE_ALIGN
;
1987 size
+= BYTES_PER_WORD
;
1991 kasan_cache_create(cachep
, &size
, &flags
);
1993 size
= ALIGN(size
, cachep
->align
);
1995 * We should restrict the number of objects in a slab to implement
1996 * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition.
1998 if (FREELIST_BYTE_INDEX
&& size
< SLAB_OBJ_MIN_SIZE
)
1999 size
= ALIGN(SLAB_OBJ_MIN_SIZE
, cachep
->align
);
2003 * To activate debug pagealloc, off-slab management is necessary
2004 * requirement. In early phase of initialization, small sized slab
2005 * doesn't get initialized so it would not be possible. So, we need
2006 * to check size >= 256. It guarantees that all necessary small
2007 * sized slab is initialized in current slab initialization sequence.
2009 if (debug_pagealloc_enabled_static() && (flags
& SLAB_POISON
) &&
2010 size
>= 256 && cachep
->object_size
> cache_line_size()) {
2011 if (size
< PAGE_SIZE
|| size
% PAGE_SIZE
== 0) {
2012 size_t tmp_size
= ALIGN(size
, PAGE_SIZE
);
2014 if (set_off_slab_cache(cachep
, tmp_size
, flags
)) {
2015 flags
|= CFLGS_OFF_SLAB
;
2016 cachep
->obj_offset
+= tmp_size
- size
;
2024 if (set_objfreelist_slab_cache(cachep
, size
, flags
)) {
2025 flags
|= CFLGS_OBJFREELIST_SLAB
;
2029 if (set_off_slab_cache(cachep
, size
, flags
)) {
2030 flags
|= CFLGS_OFF_SLAB
;
2034 if (set_on_slab_cache(cachep
, size
, flags
))
2040 cachep
->freelist_size
= cachep
->num
* sizeof(freelist_idx_t
);
2041 cachep
->flags
= flags
;
2042 cachep
->allocflags
= __GFP_COMP
;
2043 if (flags
& SLAB_CACHE_DMA
)
2044 cachep
->allocflags
|= GFP_DMA
;
2045 if (flags
& SLAB_CACHE_DMA32
)
2046 cachep
->allocflags
|= GFP_DMA32
;
2047 if (flags
& SLAB_RECLAIM_ACCOUNT
)
2048 cachep
->allocflags
|= __GFP_RECLAIMABLE
;
2049 cachep
->size
= size
;
2050 cachep
->reciprocal_buffer_size
= reciprocal_value(size
);
2054 * If we're going to use the generic kernel_map_pages()
2055 * poisoning, then it's going to smash the contents of
2056 * the redzone and userword anyhow, so switch them off.
2058 if (IS_ENABLED(CONFIG_PAGE_POISONING
) &&
2059 (cachep
->flags
& SLAB_POISON
) &&
2060 is_debug_pagealloc_cache(cachep
))
2061 cachep
->flags
&= ~(SLAB_RED_ZONE
| SLAB_STORE_USER
);
2064 if (OFF_SLAB(cachep
)) {
2065 cachep
->freelist_cache
=
2066 kmalloc_slab(cachep
->freelist_size
, 0u);
2069 err
= setup_cpu_cache(cachep
, gfp
);
2071 __kmem_cache_release(cachep
);
2079 static void check_irq_off(void)
2081 BUG_ON(!irqs_disabled());
2084 static void check_irq_on(void)
2086 BUG_ON(irqs_disabled());
2089 static void check_mutex_acquired(void)
2091 BUG_ON(!mutex_is_locked(&slab_mutex
));
2094 static void check_spinlock_acquired(struct kmem_cache
*cachep
)
2098 assert_spin_locked(&get_node(cachep
, numa_mem_id())->list_lock
);
2102 static void check_spinlock_acquired_node(struct kmem_cache
*cachep
, int node
)
2106 assert_spin_locked(&get_node(cachep
, node
)->list_lock
);
2111 #define check_irq_off() do { } while(0)
2112 #define check_irq_on() do { } while(0)
2113 #define check_mutex_acquired() do { } while(0)
2114 #define check_spinlock_acquired(x) do { } while(0)
2115 #define check_spinlock_acquired_node(x, y) do { } while(0)
2118 static void drain_array_locked(struct kmem_cache
*cachep
, struct array_cache
*ac
,
2119 int node
, bool free_all
, struct list_head
*list
)
2123 if (!ac
|| !ac
->avail
)
2126 tofree
= free_all
? ac
->avail
: (ac
->limit
+ 4) / 5;
2127 if (tofree
> ac
->avail
)
2128 tofree
= (ac
->avail
+ 1) / 2;
2130 free_block(cachep
, ac
->entry
, tofree
, node
, list
);
2131 ac
->avail
-= tofree
;
2132 memmove(ac
->entry
, &(ac
->entry
[tofree
]), sizeof(void *) * ac
->avail
);
2135 static void do_drain(void *arg
)
2137 struct kmem_cache
*cachep
= arg
;
2138 struct array_cache
*ac
;
2139 int node
= numa_mem_id();
2140 struct kmem_cache_node
*n
;
2144 ac
= cpu_cache_get(cachep
);
2145 n
= get_node(cachep
, node
);
2146 spin_lock(&n
->list_lock
);
2147 free_block(cachep
, ac
->entry
, ac
->avail
, node
, &list
);
2148 spin_unlock(&n
->list_lock
);
2150 slabs_destroy(cachep
, &list
);
2153 static void drain_cpu_caches(struct kmem_cache
*cachep
)
2155 struct kmem_cache_node
*n
;
2159 on_each_cpu(do_drain
, cachep
, 1);
2161 for_each_kmem_cache_node(cachep
, node
, n
)
2163 drain_alien_cache(cachep
, n
->alien
);
2165 for_each_kmem_cache_node(cachep
, node
, n
) {
2166 spin_lock_irq(&n
->list_lock
);
2167 drain_array_locked(cachep
, n
->shared
, node
, true, &list
);
2168 spin_unlock_irq(&n
->list_lock
);
2170 slabs_destroy(cachep
, &list
);
2175 * Remove slabs from the list of free slabs.
2176 * Specify the number of slabs to drain in tofree.
2178 * Returns the actual number of slabs released.
2180 static int drain_freelist(struct kmem_cache
*cache
,
2181 struct kmem_cache_node
*n
, int tofree
)
2183 struct list_head
*p
;
2188 while (nr_freed
< tofree
&& !list_empty(&n
->slabs_free
)) {
2190 spin_lock_irq(&n
->list_lock
);
2191 p
= n
->slabs_free
.prev
;
2192 if (p
== &n
->slabs_free
) {
2193 spin_unlock_irq(&n
->list_lock
);
2197 slab
= list_entry(p
, struct slab
, slab_list
);
2198 list_del(&slab
->slab_list
);
2202 * Safe to drop the lock. The slab is no longer linked
2205 n
->free_objects
-= cache
->num
;
2206 spin_unlock_irq(&n
->list_lock
);
2207 slab_destroy(cache
, slab
);
2214 bool __kmem_cache_empty(struct kmem_cache
*s
)
2217 struct kmem_cache_node
*n
;
2219 for_each_kmem_cache_node(s
, node
, n
)
2220 if (!list_empty(&n
->slabs_full
) ||
2221 !list_empty(&n
->slabs_partial
))
2226 int __kmem_cache_shrink(struct kmem_cache
*cachep
)
2230 struct kmem_cache_node
*n
;
2232 drain_cpu_caches(cachep
);
2235 for_each_kmem_cache_node(cachep
, node
, n
) {
2236 drain_freelist(cachep
, n
, INT_MAX
);
2238 ret
+= !list_empty(&n
->slabs_full
) ||
2239 !list_empty(&n
->slabs_partial
);
2241 return (ret
? 1 : 0);
2244 int __kmem_cache_shutdown(struct kmem_cache
*cachep
)
2246 return __kmem_cache_shrink(cachep
);
2249 void __kmem_cache_release(struct kmem_cache
*cachep
)
2252 struct kmem_cache_node
*n
;
2254 cache_random_seq_destroy(cachep
);
2256 free_percpu(cachep
->cpu_cache
);
2258 /* NUMA: free the node structures */
2259 for_each_kmem_cache_node(cachep
, i
, n
) {
2261 free_alien_cache(n
->alien
);
2263 cachep
->node
[i
] = NULL
;
2268 * Get the memory for a slab management obj.
2270 * For a slab cache when the slab descriptor is off-slab, the
2271 * slab descriptor can't come from the same cache which is being created,
2272 * Because if it is the case, that means we defer the creation of
2273 * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.
2274 * And we eventually call down to __kmem_cache_create(), which
2275 * in turn looks up in the kmalloc_{dma,}_caches for the desired-size one.
2276 * This is a "chicken-and-egg" problem.
2278 * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,
2279 * which are all initialized during kmem_cache_init().
2281 static void *alloc_slabmgmt(struct kmem_cache
*cachep
,
2282 struct slab
*slab
, int colour_off
,
2283 gfp_t local_flags
, int nodeid
)
2286 void *addr
= slab_address(slab
);
2288 slab
->s_mem
= addr
+ colour_off
;
2291 if (OBJFREELIST_SLAB(cachep
))
2293 else if (OFF_SLAB(cachep
)) {
2294 /* Slab management obj is off-slab. */
2295 freelist
= kmem_cache_alloc_node(cachep
->freelist_cache
,
2296 local_flags
, nodeid
);
2298 /* We will use last bytes at the slab for freelist */
2299 freelist
= addr
+ (PAGE_SIZE
<< cachep
->gfporder
) -
2300 cachep
->freelist_size
;
2306 static inline freelist_idx_t
get_free_obj(struct slab
*slab
, unsigned int idx
)
2308 return ((freelist_idx_t
*) slab
->freelist
)[idx
];
2311 static inline void set_free_obj(struct slab
*slab
,
2312 unsigned int idx
, freelist_idx_t val
)
2314 ((freelist_idx_t
*)(slab
->freelist
))[idx
] = val
;
2317 static void cache_init_objs_debug(struct kmem_cache
*cachep
, struct slab
*slab
)
2322 for (i
= 0; i
< cachep
->num
; i
++) {
2323 void *objp
= index_to_obj(cachep
, slab
, i
);
2325 if (cachep
->flags
& SLAB_STORE_USER
)
2326 *dbg_userword(cachep
, objp
) = NULL
;
2328 if (cachep
->flags
& SLAB_RED_ZONE
) {
2329 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2330 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2333 * Constructors are not allowed to allocate memory from the same
2334 * cache which they are a constructor for. Otherwise, deadlock.
2335 * They must also be threaded.
2337 if (cachep
->ctor
&& !(cachep
->flags
& SLAB_POISON
)) {
2338 kasan_unpoison_object_data(cachep
,
2339 objp
+ obj_offset(cachep
));
2340 cachep
->ctor(objp
+ obj_offset(cachep
));
2341 kasan_poison_object_data(
2342 cachep
, objp
+ obj_offset(cachep
));
2345 if (cachep
->flags
& SLAB_RED_ZONE
) {
2346 if (*dbg_redzone2(cachep
, objp
) != RED_INACTIVE
)
2347 slab_error(cachep
, "constructor overwrote the end of an object");
2348 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
)
2349 slab_error(cachep
, "constructor overwrote the start of an object");
2351 /* need to poison the objs? */
2352 if (cachep
->flags
& SLAB_POISON
) {
2353 poison_obj(cachep
, objp
, POISON_FREE
);
2354 slab_kernel_map(cachep
, objp
, 0);
2360 #ifdef CONFIG_SLAB_FREELIST_RANDOM
2361 /* Hold information during a freelist initialization */
2362 union freelist_init_state
{
2368 struct rnd_state rnd_state
;
2372 * Initialize the state based on the randomization method available.
2373 * return true if the pre-computed list is available, false otherwise.
2375 static bool freelist_state_initialize(union freelist_init_state
*state
,
2376 struct kmem_cache
*cachep
,
2382 /* Use best entropy available to define a random shift */
2383 rand
= get_random_int();
2385 /* Use a random state if the pre-computed list is not available */
2386 if (!cachep
->random_seq
) {
2387 prandom_seed_state(&state
->rnd_state
, rand
);
2390 state
->list
= cachep
->random_seq
;
2391 state
->count
= count
;
2392 state
->pos
= rand
% count
;
2398 /* Get the next entry on the list and randomize it using a random shift */
2399 static freelist_idx_t
next_random_slot(union freelist_init_state
*state
)
2401 if (state
->pos
>= state
->count
)
2403 return state
->list
[state
->pos
++];
2406 /* Swap two freelist entries */
2407 static void swap_free_obj(struct slab
*slab
, unsigned int a
, unsigned int b
)
2409 swap(((freelist_idx_t
*) slab
->freelist
)[a
],
2410 ((freelist_idx_t
*) slab
->freelist
)[b
]);
2414 * Shuffle the freelist initialization state based on pre-computed lists.
2415 * return true if the list was successfully shuffled, false otherwise.
2417 static bool shuffle_freelist(struct kmem_cache
*cachep
, struct slab
*slab
)
2419 unsigned int objfreelist
= 0, i
, rand
, count
= cachep
->num
;
2420 union freelist_init_state state
;
2426 precomputed
= freelist_state_initialize(&state
, cachep
, count
);
2428 /* Take a random entry as the objfreelist */
2429 if (OBJFREELIST_SLAB(cachep
)) {
2431 objfreelist
= count
- 1;
2433 objfreelist
= next_random_slot(&state
);
2434 slab
->freelist
= index_to_obj(cachep
, slab
, objfreelist
) +
2440 * On early boot, generate the list dynamically.
2441 * Later use a pre-computed list for speed.
2444 for (i
= 0; i
< count
; i
++)
2445 set_free_obj(slab
, i
, i
);
2447 /* Fisher-Yates shuffle */
2448 for (i
= count
- 1; i
> 0; i
--) {
2449 rand
= prandom_u32_state(&state
.rnd_state
);
2451 swap_free_obj(slab
, i
, rand
);
2454 for (i
= 0; i
< count
; i
++)
2455 set_free_obj(slab
, i
, next_random_slot(&state
));
2458 if (OBJFREELIST_SLAB(cachep
))
2459 set_free_obj(slab
, cachep
->num
- 1, objfreelist
);
2464 static inline bool shuffle_freelist(struct kmem_cache
*cachep
,
2469 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
2471 static void cache_init_objs(struct kmem_cache
*cachep
,
2478 cache_init_objs_debug(cachep
, slab
);
2480 /* Try to randomize the freelist if enabled */
2481 shuffled
= shuffle_freelist(cachep
, slab
);
2483 if (!shuffled
&& OBJFREELIST_SLAB(cachep
)) {
2484 slab
->freelist
= index_to_obj(cachep
, slab
, cachep
->num
- 1) +
2488 for (i
= 0; i
< cachep
->num
; i
++) {
2489 objp
= index_to_obj(cachep
, slab
, i
);
2490 objp
= kasan_init_slab_obj(cachep
, objp
);
2492 /* constructor could break poison info */
2493 if (DEBUG
== 0 && cachep
->ctor
) {
2494 kasan_unpoison_object_data(cachep
, objp
);
2496 kasan_poison_object_data(cachep
, objp
);
2500 set_free_obj(slab
, i
, i
);
2504 static void *slab_get_obj(struct kmem_cache
*cachep
, struct slab
*slab
)
2508 objp
= index_to_obj(cachep
, slab
, get_free_obj(slab
, slab
->active
));
2514 static void slab_put_obj(struct kmem_cache
*cachep
,
2515 struct slab
*slab
, void *objp
)
2517 unsigned int objnr
= obj_to_index(cachep
, slab
, objp
);
2521 /* Verify double free bug */
2522 for (i
= slab
->active
; i
< cachep
->num
; i
++) {
2523 if (get_free_obj(slab
, i
) == objnr
) {
2524 pr_err("slab: double free detected in cache '%s', objp %px\n",
2525 cachep
->name
, objp
);
2531 if (!slab
->freelist
)
2532 slab
->freelist
= objp
+ obj_offset(cachep
);
2534 set_free_obj(slab
, slab
->active
, objnr
);
2538 * Grow (by 1) the number of slabs within a cache. This is called by
2539 * kmem_cache_alloc() when there are no active objs left in a cache.
2541 static struct slab
*cache_grow_begin(struct kmem_cache
*cachep
,
2542 gfp_t flags
, int nodeid
)
2548 struct kmem_cache_node
*n
;
2552 * Be lazy and only check for valid flags here, keeping it out of the
2553 * critical path in kmem_cache_alloc().
2555 if (unlikely(flags
& GFP_SLAB_BUG_MASK
))
2556 flags
= kmalloc_fix_flags(flags
);
2558 WARN_ON_ONCE(cachep
->ctor
&& (flags
& __GFP_ZERO
));
2559 local_flags
= flags
& (GFP_CONSTRAINT_MASK
|GFP_RECLAIM_MASK
);
2562 if (gfpflags_allow_blocking(local_flags
))
2566 * Get mem for the objs. Attempt to allocate a physical page from
2569 slab
= kmem_getpages(cachep
, local_flags
, nodeid
);
2573 slab_node
= slab_nid(slab
);
2574 n
= get_node(cachep
, slab_node
);
2576 /* Get colour for the slab, and cal the next value. */
2578 if (n
->colour_next
>= cachep
->colour
)
2581 offset
= n
->colour_next
;
2582 if (offset
>= cachep
->colour
)
2585 offset
*= cachep
->colour_off
;
2588 * Call kasan_poison_slab() before calling alloc_slabmgmt(), so
2589 * page_address() in the latter returns a non-tagged pointer,
2590 * as it should be for slab pages.
2592 kasan_poison_slab(slab
);
2594 /* Get slab management. */
2595 freelist
= alloc_slabmgmt(cachep
, slab
, offset
,
2596 local_flags
& ~GFP_CONSTRAINT_MASK
, slab_node
);
2597 if (OFF_SLAB(cachep
) && !freelist
)
2600 slab
->slab_cache
= cachep
;
2601 slab
->freelist
= freelist
;
2603 cache_init_objs(cachep
, slab
);
2605 if (gfpflags_allow_blocking(local_flags
))
2606 local_irq_disable();
2611 kmem_freepages(cachep
, slab
);
2613 if (gfpflags_allow_blocking(local_flags
))
2614 local_irq_disable();
2618 static void cache_grow_end(struct kmem_cache
*cachep
, struct slab
*slab
)
2620 struct kmem_cache_node
*n
;
2628 INIT_LIST_HEAD(&slab
->slab_list
);
2629 n
= get_node(cachep
, slab_nid(slab
));
2631 spin_lock(&n
->list_lock
);
2633 if (!slab
->active
) {
2634 list_add_tail(&slab
->slab_list
, &n
->slabs_free
);
2637 fixup_slab_list(cachep
, n
, slab
, &list
);
2639 STATS_INC_GROWN(cachep
);
2640 n
->free_objects
+= cachep
->num
- slab
->active
;
2641 spin_unlock(&n
->list_lock
);
2643 fixup_objfreelist_debug(cachep
, &list
);
2649 * Perform extra freeing checks:
2650 * - detect bad pointers.
2651 * - POISON/RED_ZONE checking
2653 static void kfree_debugcheck(const void *objp
)
2655 if (!virt_addr_valid(objp
)) {
2656 pr_err("kfree_debugcheck: out of range ptr %lxh\n",
2657 (unsigned long)objp
);
2662 static inline void verify_redzone_free(struct kmem_cache
*cache
, void *obj
)
2664 unsigned long long redzone1
, redzone2
;
2666 redzone1
= *dbg_redzone1(cache
, obj
);
2667 redzone2
= *dbg_redzone2(cache
, obj
);
2672 if (redzone1
== RED_ACTIVE
&& redzone2
== RED_ACTIVE
)
2675 if (redzone1
== RED_INACTIVE
&& redzone2
== RED_INACTIVE
)
2676 slab_error(cache
, "double free detected");
2678 slab_error(cache
, "memory outside object was overwritten");
2680 pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
2681 obj
, redzone1
, redzone2
);
2684 static void *cache_free_debugcheck(struct kmem_cache
*cachep
, void *objp
,
2685 unsigned long caller
)
2690 BUG_ON(virt_to_cache(objp
) != cachep
);
2692 objp
-= obj_offset(cachep
);
2693 kfree_debugcheck(objp
);
2694 slab
= virt_to_slab(objp
);
2696 if (cachep
->flags
& SLAB_RED_ZONE
) {
2697 verify_redzone_free(cachep
, objp
);
2698 *dbg_redzone1(cachep
, objp
) = RED_INACTIVE
;
2699 *dbg_redzone2(cachep
, objp
) = RED_INACTIVE
;
2701 if (cachep
->flags
& SLAB_STORE_USER
)
2702 *dbg_userword(cachep
, objp
) = (void *)caller
;
2704 objnr
= obj_to_index(cachep
, slab
, objp
);
2706 BUG_ON(objnr
>= cachep
->num
);
2707 BUG_ON(objp
!= index_to_obj(cachep
, slab
, objnr
));
2709 if (cachep
->flags
& SLAB_POISON
) {
2710 poison_obj(cachep
, objp
, POISON_FREE
);
2711 slab_kernel_map(cachep
, objp
, 0);
2717 #define kfree_debugcheck(x) do { } while(0)
2718 #define cache_free_debugcheck(x, objp, z) (objp)
2721 static inline void fixup_objfreelist_debug(struct kmem_cache
*cachep
,
2729 objp
= next
- obj_offset(cachep
);
2730 next
= *(void **)next
;
2731 poison_obj(cachep
, objp
, POISON_FREE
);
2736 static inline void fixup_slab_list(struct kmem_cache
*cachep
,
2737 struct kmem_cache_node
*n
, struct slab
*slab
,
2740 /* move slabp to correct slabp list: */
2741 list_del(&slab
->slab_list
);
2742 if (slab
->active
== cachep
->num
) {
2743 list_add(&slab
->slab_list
, &n
->slabs_full
);
2744 if (OBJFREELIST_SLAB(cachep
)) {
2746 /* Poisoning will be done without holding the lock */
2747 if (cachep
->flags
& SLAB_POISON
) {
2748 void **objp
= slab
->freelist
;
2754 slab
->freelist
= NULL
;
2757 list_add(&slab
->slab_list
, &n
->slabs_partial
);
2760 /* Try to find non-pfmemalloc slab if needed */
2761 static noinline
struct slab
*get_valid_first_slab(struct kmem_cache_node
*n
,
2762 struct slab
*slab
, bool pfmemalloc
)
2770 if (!slab_test_pfmemalloc(slab
))
2773 /* No need to keep pfmemalloc slab if we have enough free objects */
2774 if (n
->free_objects
> n
->free_limit
) {
2775 slab_clear_pfmemalloc(slab
);
2779 /* Move pfmemalloc slab to the end of list to speed up next search */
2780 list_del(&slab
->slab_list
);
2781 if (!slab
->active
) {
2782 list_add_tail(&slab
->slab_list
, &n
->slabs_free
);
2785 list_add_tail(&slab
->slab_list
, &n
->slabs_partial
);
2787 list_for_each_entry(slab
, &n
->slabs_partial
, slab_list
) {
2788 if (!slab_test_pfmemalloc(slab
))
2792 n
->free_touched
= 1;
2793 list_for_each_entry(slab
, &n
->slabs_free
, slab_list
) {
2794 if (!slab_test_pfmemalloc(slab
)) {
2803 static struct slab
*get_first_slab(struct kmem_cache_node
*n
, bool pfmemalloc
)
2807 assert_spin_locked(&n
->list_lock
);
2808 slab
= list_first_entry_or_null(&n
->slabs_partial
, struct slab
,
2811 n
->free_touched
= 1;
2812 slab
= list_first_entry_or_null(&n
->slabs_free
, struct slab
,
2818 if (sk_memalloc_socks())
2819 slab
= get_valid_first_slab(n
, slab
, pfmemalloc
);
2824 static noinline
void *cache_alloc_pfmemalloc(struct kmem_cache
*cachep
,
2825 struct kmem_cache_node
*n
, gfp_t flags
)
2831 if (!gfp_pfmemalloc_allowed(flags
))
2834 spin_lock(&n
->list_lock
);
2835 slab
= get_first_slab(n
, true);
2837 spin_unlock(&n
->list_lock
);
2841 obj
= slab_get_obj(cachep
, slab
);
2844 fixup_slab_list(cachep
, n
, slab
, &list
);
2846 spin_unlock(&n
->list_lock
);
2847 fixup_objfreelist_debug(cachep
, &list
);
2853 * Slab list should be fixed up by fixup_slab_list() for existing slab
2854 * or cache_grow_end() for new slab
2856 static __always_inline
int alloc_block(struct kmem_cache
*cachep
,
2857 struct array_cache
*ac
, struct slab
*slab
, int batchcount
)
2860 * There must be at least one object available for
2863 BUG_ON(slab
->active
>= cachep
->num
);
2865 while (slab
->active
< cachep
->num
&& batchcount
--) {
2866 STATS_INC_ALLOCED(cachep
);
2867 STATS_INC_ACTIVE(cachep
);
2868 STATS_SET_HIGH(cachep
);
2870 ac
->entry
[ac
->avail
++] = slab_get_obj(cachep
, slab
);
2876 static void *cache_alloc_refill(struct kmem_cache
*cachep
, gfp_t flags
)
2879 struct kmem_cache_node
*n
;
2880 struct array_cache
*ac
, *shared
;
2886 node
= numa_mem_id();
2888 ac
= cpu_cache_get(cachep
);
2889 batchcount
= ac
->batchcount
;
2890 if (!ac
->touched
&& batchcount
> BATCHREFILL_LIMIT
) {
2892 * If there was little recent activity on this cache, then
2893 * perform only a partial refill. Otherwise we could generate
2896 batchcount
= BATCHREFILL_LIMIT
;
2898 n
= get_node(cachep
, node
);
2900 BUG_ON(ac
->avail
> 0 || !n
);
2901 shared
= READ_ONCE(n
->shared
);
2902 if (!n
->free_objects
&& (!shared
|| !shared
->avail
))
2905 spin_lock(&n
->list_lock
);
2906 shared
= READ_ONCE(n
->shared
);
2908 /* See if we can refill from the shared array */
2909 if (shared
&& transfer_objects(ac
, shared
, batchcount
)) {
2910 shared
->touched
= 1;
2914 while (batchcount
> 0) {
2915 /* Get slab alloc is to come from. */
2916 slab
= get_first_slab(n
, false);
2920 check_spinlock_acquired(cachep
);
2922 batchcount
= alloc_block(cachep
, ac
, slab
, batchcount
);
2923 fixup_slab_list(cachep
, n
, slab
, &list
);
2927 n
->free_objects
-= ac
->avail
;
2929 spin_unlock(&n
->list_lock
);
2930 fixup_objfreelist_debug(cachep
, &list
);
2933 if (unlikely(!ac
->avail
)) {
2934 /* Check if we can use obj in pfmemalloc slab */
2935 if (sk_memalloc_socks()) {
2936 void *obj
= cache_alloc_pfmemalloc(cachep
, n
, flags
);
2942 slab
= cache_grow_begin(cachep
, gfp_exact_node(flags
), node
);
2945 * cache_grow_begin() can reenable interrupts,
2946 * then ac could change.
2948 ac
= cpu_cache_get(cachep
);
2949 if (!ac
->avail
&& slab
)
2950 alloc_block(cachep
, ac
, slab
, batchcount
);
2951 cache_grow_end(cachep
, slab
);
2958 return ac
->entry
[--ac
->avail
];
2962 static void *cache_alloc_debugcheck_after(struct kmem_cache
*cachep
,
2963 gfp_t flags
, void *objp
, unsigned long caller
)
2965 WARN_ON_ONCE(cachep
->ctor
&& (flags
& __GFP_ZERO
));
2966 if (!objp
|| is_kfence_address(objp
))
2968 if (cachep
->flags
& SLAB_POISON
) {
2969 check_poison_obj(cachep
, objp
);
2970 slab_kernel_map(cachep
, objp
, 1);
2971 poison_obj(cachep
, objp
, POISON_INUSE
);
2973 if (cachep
->flags
& SLAB_STORE_USER
)
2974 *dbg_userword(cachep
, objp
) = (void *)caller
;
2976 if (cachep
->flags
& SLAB_RED_ZONE
) {
2977 if (*dbg_redzone1(cachep
, objp
) != RED_INACTIVE
||
2978 *dbg_redzone2(cachep
, objp
) != RED_INACTIVE
) {
2979 slab_error(cachep
, "double free, or memory outside object was overwritten");
2980 pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
2981 objp
, *dbg_redzone1(cachep
, objp
),
2982 *dbg_redzone2(cachep
, objp
));
2984 *dbg_redzone1(cachep
, objp
) = RED_ACTIVE
;
2985 *dbg_redzone2(cachep
, objp
) = RED_ACTIVE
;
2988 objp
+= obj_offset(cachep
);
2989 if (cachep
->ctor
&& cachep
->flags
& SLAB_POISON
)
2991 if ((unsigned long)objp
& (arch_slab_minalign() - 1)) {
2992 pr_err("0x%px: not aligned to arch_slab_minalign()=%u\n", objp
,
2993 arch_slab_minalign());
2998 #define cache_alloc_debugcheck_after(a, b, objp, d) (objp)
3001 static inline void *____cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3004 struct array_cache
*ac
;
3008 ac
= cpu_cache_get(cachep
);
3009 if (likely(ac
->avail
)) {
3011 objp
= ac
->entry
[--ac
->avail
];
3013 STATS_INC_ALLOCHIT(cachep
);
3017 STATS_INC_ALLOCMISS(cachep
);
3018 objp
= cache_alloc_refill(cachep
, flags
);
3020 * the 'ac' may be updated by cache_alloc_refill(),
3021 * and kmemleak_erase() requires its correct value.
3023 ac
= cpu_cache_get(cachep
);
3027 * To avoid a false negative, if an object that is in one of the
3028 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3029 * treat the array pointers as a reference to the object.
3032 kmemleak_erase(&ac
->entry
[ac
->avail
]);
3037 static void *____cache_alloc_node(struct kmem_cache
*, gfp_t
, int);
3040 * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
3042 * If we are in_interrupt, then process context, including cpusets and
3043 * mempolicy, may not apply and should not be used for allocation policy.
3045 static void *alternate_node_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3047 int nid_alloc
, nid_here
;
3049 if (in_interrupt() || (flags
& __GFP_THISNODE
))
3051 nid_alloc
= nid_here
= numa_mem_id();
3052 if (cpuset_do_slab_mem_spread() && (cachep
->flags
& SLAB_MEM_SPREAD
))
3053 nid_alloc
= cpuset_slab_spread_node();
3054 else if (current
->mempolicy
)
3055 nid_alloc
= mempolicy_slab_node();
3056 if (nid_alloc
!= nid_here
)
3057 return ____cache_alloc_node(cachep
, flags
, nid_alloc
);
3062 * Fallback function if there was no memory available and no objects on a
3063 * certain node and fall back is permitted. First we scan all the
3064 * available node for available objects. If that fails then we
3065 * perform an allocation without specifying a node. This allows the page
3066 * allocator to do its reclaim / fallback magic. We then insert the
3067 * slab into the proper nodelist and then allocate from it.
3069 static void *fallback_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3071 struct zonelist
*zonelist
;
3074 enum zone_type highest_zoneidx
= gfp_zone(flags
);
3078 unsigned int cpuset_mems_cookie
;
3080 if (flags
& __GFP_THISNODE
)
3084 cpuset_mems_cookie
= read_mems_allowed_begin();
3085 zonelist
= node_zonelist(mempolicy_slab_node(), flags
);
3089 * Look through allowed nodes for objects available
3090 * from existing per node queues.
3092 for_each_zone_zonelist(zone
, z
, zonelist
, highest_zoneidx
) {
3093 nid
= zone_to_nid(zone
);
3095 if (cpuset_zone_allowed(zone
, flags
) &&
3096 get_node(cache
, nid
) &&
3097 get_node(cache
, nid
)->free_objects
) {
3098 obj
= ____cache_alloc_node(cache
,
3099 gfp_exact_node(flags
), nid
);
3107 * This allocation will be performed within the constraints
3108 * of the current cpuset / memory policy requirements.
3109 * We may trigger various forms of reclaim on the allowed
3110 * set and go into memory reserves if necessary.
3112 slab
= cache_grow_begin(cache
, flags
, numa_mem_id());
3113 cache_grow_end(cache
, slab
);
3115 nid
= slab_nid(slab
);
3116 obj
= ____cache_alloc_node(cache
,
3117 gfp_exact_node(flags
), nid
);
3120 * Another processor may allocate the objects in
3121 * the slab since we are not holding any locks.
3128 if (unlikely(!obj
&& read_mems_allowed_retry(cpuset_mems_cookie
)))
3134 * An interface to enable slab creation on nodeid
3136 static void *____cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
,
3140 struct kmem_cache_node
*n
;
3144 VM_BUG_ON(nodeid
< 0 || nodeid
>= MAX_NUMNODES
);
3145 n
= get_node(cachep
, nodeid
);
3149 spin_lock(&n
->list_lock
);
3150 slab
= get_first_slab(n
, false);
3154 check_spinlock_acquired_node(cachep
, nodeid
);
3156 STATS_INC_NODEALLOCS(cachep
);
3157 STATS_INC_ACTIVE(cachep
);
3158 STATS_SET_HIGH(cachep
);
3160 BUG_ON(slab
->active
== cachep
->num
);
3162 obj
= slab_get_obj(cachep
, slab
);
3165 fixup_slab_list(cachep
, n
, slab
, &list
);
3167 spin_unlock(&n
->list_lock
);
3168 fixup_objfreelist_debug(cachep
, &list
);
3172 spin_unlock(&n
->list_lock
);
3173 slab
= cache_grow_begin(cachep
, gfp_exact_node(flags
), nodeid
);
3175 /* This slab isn't counted yet so don't update free_objects */
3176 obj
= slab_get_obj(cachep
, slab
);
3178 cache_grow_end(cachep
, slab
);
3180 return obj
? obj
: fallback_alloc(cachep
, flags
);
3183 static __always_inline
void *
3184 slab_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
, size_t orig_size
,
3185 unsigned long caller
)
3187 unsigned long save_flags
;
3189 int slab_node
= numa_mem_id();
3190 struct obj_cgroup
*objcg
= NULL
;
3193 flags
&= gfp_allowed_mask
;
3194 cachep
= slab_pre_alloc_hook(cachep
, NULL
, &objcg
, 1, flags
);
3195 if (unlikely(!cachep
))
3198 ptr
= kfence_alloc(cachep
, orig_size
, flags
);
3202 local_irq_save(save_flags
);
3204 if (nodeid
== NUMA_NO_NODE
)
3207 if (unlikely(!get_node(cachep
, nodeid
))) {
3208 /* Node not bootstrapped yet */
3209 ptr
= fallback_alloc(cachep
, flags
);
3213 if (nodeid
== slab_node
) {
3215 * Use the locally cached objects if possible.
3216 * However ____cache_alloc does not allow fallback
3217 * to other nodes. It may fail while we still have
3218 * objects on other nodes available.
3220 ptr
= ____cache_alloc(cachep
, flags
);
3224 /* ___cache_alloc_node can fall back to other nodes */
3225 ptr
= ____cache_alloc_node(cachep
, flags
, nodeid
);
3227 local_irq_restore(save_flags
);
3228 ptr
= cache_alloc_debugcheck_after(cachep
, flags
, ptr
, caller
);
3229 init
= slab_want_init_on_alloc(flags
, cachep
);
3232 slab_post_alloc_hook(cachep
, objcg
, flags
, 1, &ptr
, init
);
3236 static __always_inline
void *
3237 __do_cache_alloc(struct kmem_cache
*cache
, gfp_t flags
)
3241 if (current
->mempolicy
|| cpuset_do_slab_mem_spread()) {
3242 objp
= alternate_node_alloc(cache
, flags
);
3246 objp
= ____cache_alloc(cache
, flags
);
3249 * We may just have run out of memory on the local node.
3250 * ____cache_alloc_node() knows how to locate memory on other nodes
3253 objp
= ____cache_alloc_node(cache
, flags
, numa_mem_id());
3260 static __always_inline
void *
3261 __do_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3263 return ____cache_alloc(cachep
, flags
);
3266 #endif /* CONFIG_NUMA */
3268 static __always_inline
void *
3269 slab_alloc(struct kmem_cache
*cachep
, struct list_lru
*lru
, gfp_t flags
,
3270 size_t orig_size
, unsigned long caller
)
3272 unsigned long save_flags
;
3274 struct obj_cgroup
*objcg
= NULL
;
3277 flags
&= gfp_allowed_mask
;
3278 cachep
= slab_pre_alloc_hook(cachep
, lru
, &objcg
, 1, flags
);
3279 if (unlikely(!cachep
))
3282 objp
= kfence_alloc(cachep
, orig_size
, flags
);
3286 local_irq_save(save_flags
);
3287 objp
= __do_cache_alloc(cachep
, flags
);
3288 local_irq_restore(save_flags
);
3289 objp
= cache_alloc_debugcheck_after(cachep
, flags
, objp
, caller
);
3291 init
= slab_want_init_on_alloc(flags
, cachep
);
3294 slab_post_alloc_hook(cachep
, objcg
, flags
, 1, &objp
, init
);
3299 * Caller needs to acquire correct kmem_cache_node's list_lock
3300 * @list: List of detached free slabs should be freed by caller
3302 static void free_block(struct kmem_cache
*cachep
, void **objpp
,
3303 int nr_objects
, int node
, struct list_head
*list
)
3306 struct kmem_cache_node
*n
= get_node(cachep
, node
);
3309 n
->free_objects
+= nr_objects
;
3311 for (i
= 0; i
< nr_objects
; i
++) {
3317 slab
= virt_to_slab(objp
);
3318 list_del(&slab
->slab_list
);
3319 check_spinlock_acquired_node(cachep
, node
);
3320 slab_put_obj(cachep
, slab
, objp
);
3321 STATS_DEC_ACTIVE(cachep
);
3323 /* fixup slab chains */
3324 if (slab
->active
== 0) {
3325 list_add(&slab
->slab_list
, &n
->slabs_free
);
3328 /* Unconditionally move a slab to the end of the
3329 * partial list on free - maximum time for the
3330 * other objects to be freed, too.
3332 list_add_tail(&slab
->slab_list
, &n
->slabs_partial
);
3336 while (n
->free_objects
> n
->free_limit
&& !list_empty(&n
->slabs_free
)) {
3337 n
->free_objects
-= cachep
->num
;
3339 slab
= list_last_entry(&n
->slabs_free
, struct slab
, slab_list
);
3340 list_move(&slab
->slab_list
, list
);
3346 static void cache_flusharray(struct kmem_cache
*cachep
, struct array_cache
*ac
)
3349 struct kmem_cache_node
*n
;
3350 int node
= numa_mem_id();
3353 batchcount
= ac
->batchcount
;
3356 n
= get_node(cachep
, node
);
3357 spin_lock(&n
->list_lock
);
3359 struct array_cache
*shared_array
= n
->shared
;
3360 int max
= shared_array
->limit
- shared_array
->avail
;
3362 if (batchcount
> max
)
3364 memcpy(&(shared_array
->entry
[shared_array
->avail
]),
3365 ac
->entry
, sizeof(void *) * batchcount
);
3366 shared_array
->avail
+= batchcount
;
3371 free_block(cachep
, ac
->entry
, batchcount
, node
, &list
);
3378 list_for_each_entry(slab
, &n
->slabs_free
, slab_list
) {
3379 BUG_ON(slab
->active
);
3383 STATS_SET_FREEABLE(cachep
, i
);
3386 spin_unlock(&n
->list_lock
);
3387 ac
->avail
-= batchcount
;
3388 memmove(ac
->entry
, &(ac
->entry
[batchcount
]), sizeof(void *)*ac
->avail
);
3389 slabs_destroy(cachep
, &list
);
3393 * Release an obj back to its cache. If the obj has a constructed state, it must
3394 * be in this state _before_ it is released. Called with disabled ints.
3396 static __always_inline
void __cache_free(struct kmem_cache
*cachep
, void *objp
,
3397 unsigned long caller
)
3401 memcg_slab_free_hook(cachep
, virt_to_slab(objp
), &objp
, 1);
3403 if (is_kfence_address(objp
)) {
3404 kmemleak_free_recursive(objp
, cachep
->flags
);
3405 __kfence_free(objp
);
3410 * As memory initialization might be integrated into KASAN,
3411 * kasan_slab_free and initialization memset must be
3412 * kept together to avoid discrepancies in behavior.
3414 init
= slab_want_init_on_free(cachep
);
3415 if (init
&& !kasan_has_integrated_init())
3416 memset(objp
, 0, cachep
->object_size
);
3417 /* KASAN might put objp into memory quarantine, delaying its reuse. */
3418 if (kasan_slab_free(cachep
, objp
, init
))
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 kmemleak_free_recursive(objp
, cachep
->flags
);
3436 objp
= cache_free_debugcheck(cachep
, objp
, caller
);
3439 * Skip calling cache_free_alien() when the platform is not numa.
3440 * This will avoid cache misses that happen while accessing slabp (which
3441 * is per page memory reference) to get nodeid. Instead use a global
3442 * variable to skip the call, which is mostly likely to be present in
3445 if (nr_online_nodes
> 1 && cache_free_alien(cachep
, objp
))
3448 if (ac
->avail
< ac
->limit
) {
3449 STATS_INC_FREEHIT(cachep
);
3451 STATS_INC_FREEMISS(cachep
);
3452 cache_flusharray(cachep
, ac
);
3455 if (sk_memalloc_socks()) {
3456 struct slab
*slab
= virt_to_slab(objp
);
3458 if (unlikely(slab_test_pfmemalloc(slab
))) {
3459 cache_free_pfmemalloc(cachep
, slab
, objp
);
3464 __free_one(ac
, objp
);
3467 static __always_inline
3468 void *__kmem_cache_alloc_lru(struct kmem_cache
*cachep
, struct list_lru
*lru
,
3471 void *ret
= slab_alloc(cachep
, lru
, flags
, cachep
->object_size
, _RET_IP_
);
3473 trace_kmem_cache_alloc(_RET_IP_
, ret
, cachep
,
3474 cachep
->object_size
, cachep
->size
, flags
);
3480 * kmem_cache_alloc - Allocate an object
3481 * @cachep: The cache to allocate from.
3482 * @flags: See kmalloc().
3484 * Allocate an object from this cache. The flags are only relevant
3485 * if the cache has no available objects.
3487 * Return: pointer to the new object or %NULL in case of error
3489 void *kmem_cache_alloc(struct kmem_cache
*cachep
, gfp_t flags
)
3491 return __kmem_cache_alloc_lru(cachep
, NULL
, flags
);
3493 EXPORT_SYMBOL(kmem_cache_alloc
);
3495 void *kmem_cache_alloc_lru(struct kmem_cache
*cachep
, struct list_lru
*lru
,
3498 return __kmem_cache_alloc_lru(cachep
, lru
, flags
);
3500 EXPORT_SYMBOL(kmem_cache_alloc_lru
);
3502 static __always_inline
void
3503 cache_alloc_debugcheck_after_bulk(struct kmem_cache
*s
, gfp_t flags
,
3504 size_t size
, void **p
, unsigned long caller
)
3508 for (i
= 0; i
< size
; i
++)
3509 p
[i
] = cache_alloc_debugcheck_after(s
, flags
, p
[i
], caller
);
3512 int kmem_cache_alloc_bulk(struct kmem_cache
*s
, gfp_t flags
, size_t size
,
3516 struct obj_cgroup
*objcg
= NULL
;
3518 s
= slab_pre_alloc_hook(s
, NULL
, &objcg
, size
, flags
);
3522 local_irq_disable();
3523 for (i
= 0; i
< size
; i
++) {
3524 void *objp
= kfence_alloc(s
, s
->object_size
, flags
) ?: __do_cache_alloc(s
, flags
);
3526 if (unlikely(!objp
))
3532 cache_alloc_debugcheck_after_bulk(s
, flags
, size
, p
, _RET_IP_
);
3535 * memcg and kmem_cache debug support and memory initialization.
3536 * Done outside of the IRQ disabled section.
3538 slab_post_alloc_hook(s
, objcg
, flags
, size
, p
,
3539 slab_want_init_on_alloc(flags
, s
));
3540 /* FIXME: Trace call missing. Christoph would like a bulk variant */
3544 cache_alloc_debugcheck_after_bulk(s
, flags
, i
, p
, _RET_IP_
);
3545 slab_post_alloc_hook(s
, objcg
, flags
, i
, p
, false);
3546 kmem_cache_free_bulk(s
, i
, p
);
3549 EXPORT_SYMBOL(kmem_cache_alloc_bulk
);
3551 #ifdef CONFIG_TRACING
3553 kmem_cache_alloc_trace(struct kmem_cache
*cachep
, gfp_t flags
, size_t size
)
3557 ret
= slab_alloc(cachep
, NULL
, flags
, size
, _RET_IP_
);
3559 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3560 trace_kmalloc(_RET_IP_
, ret
, cachep
,
3561 size
, cachep
->size
, flags
);
3564 EXPORT_SYMBOL(kmem_cache_alloc_trace
);
3569 * kmem_cache_alloc_node - Allocate an object on the specified node
3570 * @cachep: The cache to allocate from.
3571 * @flags: See kmalloc().
3572 * @nodeid: node number of the target node.
3574 * Identical to kmem_cache_alloc but it will allocate memory on the given
3575 * node, which can improve the performance for cpu bound structures.
3577 * Fallback to other node is possible if __GFP_THISNODE is not set.
3579 * Return: pointer to the new object or %NULL in case of error
3581 void *kmem_cache_alloc_node(struct kmem_cache
*cachep
, gfp_t flags
, int nodeid
)
3583 void *ret
= slab_alloc_node(cachep
, flags
, nodeid
, cachep
->object_size
, _RET_IP_
);
3585 trace_kmem_cache_alloc_node(_RET_IP_
, ret
, cachep
,
3586 cachep
->object_size
, cachep
->size
,
3591 EXPORT_SYMBOL(kmem_cache_alloc_node
);
3593 #ifdef CONFIG_TRACING
3594 void *kmem_cache_alloc_node_trace(struct kmem_cache
*cachep
,
3601 ret
= slab_alloc_node(cachep
, flags
, nodeid
, size
, _RET_IP_
);
3603 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3604 trace_kmalloc_node(_RET_IP_
, ret
, cachep
,
3609 EXPORT_SYMBOL(kmem_cache_alloc_node_trace
);
3612 static __always_inline
void *
3613 __do_kmalloc_node(size_t size
, gfp_t flags
, int node
, unsigned long caller
)
3615 struct kmem_cache
*cachep
;
3618 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3620 cachep
= kmalloc_slab(size
, flags
);
3621 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3623 ret
= kmem_cache_alloc_node_trace(cachep
, flags
, node
, size
);
3624 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3629 void *__kmalloc_node(size_t size
, gfp_t flags
, int node
)
3631 return __do_kmalloc_node(size
, flags
, node
, _RET_IP_
);
3633 EXPORT_SYMBOL(__kmalloc_node
);
3635 void *__kmalloc_node_track_caller(size_t size
, gfp_t flags
,
3636 int node
, unsigned long caller
)
3638 return __do_kmalloc_node(size
, flags
, node
, caller
);
3640 EXPORT_SYMBOL(__kmalloc_node_track_caller
);
3641 #endif /* CONFIG_NUMA */
3643 #ifdef CONFIG_PRINTK
3644 void __kmem_obj_info(struct kmem_obj_info
*kpp
, void *object
, struct slab
*slab
)
3646 struct kmem_cache
*cachep
;
3650 kpp
->kp_ptr
= object
;
3651 kpp
->kp_slab
= slab
;
3652 cachep
= slab
->slab_cache
;
3653 kpp
->kp_slab_cache
= cachep
;
3654 objp
= object
- obj_offset(cachep
);
3655 kpp
->kp_data_offset
= obj_offset(cachep
);
3656 slab
= virt_to_slab(objp
);
3657 objnr
= obj_to_index(cachep
, slab
, objp
);
3658 objp
= index_to_obj(cachep
, slab
, objnr
);
3659 kpp
->kp_objp
= objp
;
3660 if (DEBUG
&& cachep
->flags
& SLAB_STORE_USER
)
3661 kpp
->kp_ret
= *dbg_userword(cachep
, objp
);
3666 * __do_kmalloc - allocate memory
3667 * @size: how many bytes of memory are required.
3668 * @flags: the type of memory to allocate (see kmalloc).
3669 * @caller: function caller for debug tracking of the caller
3671 * Return: pointer to the allocated memory or %NULL in case of error
3673 static __always_inline
void *__do_kmalloc(size_t size
, gfp_t flags
,
3674 unsigned long caller
)
3676 struct kmem_cache
*cachep
;
3679 if (unlikely(size
> KMALLOC_MAX_CACHE_SIZE
))
3681 cachep
= kmalloc_slab(size
, flags
);
3682 if (unlikely(ZERO_OR_NULL_PTR(cachep
)))
3684 ret
= slab_alloc(cachep
, NULL
, flags
, size
, caller
);
3686 ret
= kasan_kmalloc(cachep
, ret
, size
, flags
);
3687 trace_kmalloc(caller
, ret
, cachep
,
3688 size
, cachep
->size
, flags
);
3693 void *__kmalloc(size_t size
, gfp_t flags
)
3695 return __do_kmalloc(size
, flags
, _RET_IP_
);
3697 EXPORT_SYMBOL(__kmalloc
);
3699 void *__kmalloc_track_caller(size_t size
, gfp_t flags
, unsigned long caller
)
3701 return __do_kmalloc(size
, flags
, caller
);
3703 EXPORT_SYMBOL(__kmalloc_track_caller
);
3706 * kmem_cache_free - Deallocate an object
3707 * @cachep: The cache the allocation was from.
3708 * @objp: The previously allocated object.
3710 * Free an object which was previously allocated from this
3713 void kmem_cache_free(struct kmem_cache
*cachep
, void *objp
)
3715 unsigned long flags
;
3716 cachep
= cache_from_obj(cachep
, objp
);
3720 trace_kmem_cache_free(_RET_IP_
, objp
, cachep
->name
);
3721 local_irq_save(flags
);
3722 debug_check_no_locks_freed(objp
, cachep
->object_size
);
3723 if (!(cachep
->flags
& SLAB_DEBUG_OBJECTS
))
3724 debug_check_no_obj_freed(objp
, cachep
->object_size
);
3725 __cache_free(cachep
, objp
, _RET_IP_
);
3726 local_irq_restore(flags
);
3728 EXPORT_SYMBOL(kmem_cache_free
);
3730 void kmem_cache_free_bulk(struct kmem_cache
*orig_s
, size_t size
, void **p
)
3732 struct kmem_cache
*s
;
3735 local_irq_disable();
3736 for (i
= 0; i
< size
; i
++) {
3739 if (!orig_s
) /* called via kfree_bulk */
3740 s
= virt_to_cache(objp
);
3742 s
= cache_from_obj(orig_s
, objp
);
3746 debug_check_no_locks_freed(objp
, s
->object_size
);
3747 if (!(s
->flags
& SLAB_DEBUG_OBJECTS
))
3748 debug_check_no_obj_freed(objp
, s
->object_size
);
3750 __cache_free(s
, objp
, _RET_IP_
);
3754 /* FIXME: add tracing */
3756 EXPORT_SYMBOL(kmem_cache_free_bulk
);
3759 * kfree - free previously allocated memory
3760 * @objp: pointer returned by kmalloc.
3762 * If @objp is NULL, no operation is performed.
3764 * Don't free memory not originally allocated by kmalloc()
3765 * or you will run into trouble.
3767 void kfree(const void *objp
)
3769 struct kmem_cache
*c
;
3770 unsigned long flags
;
3772 trace_kfree(_RET_IP_
, objp
);
3774 if (unlikely(ZERO_OR_NULL_PTR(objp
)))
3776 local_irq_save(flags
);
3777 kfree_debugcheck(objp
);
3778 c
= virt_to_cache(objp
);
3780 local_irq_restore(flags
);
3783 debug_check_no_locks_freed(objp
, c
->object_size
);
3785 debug_check_no_obj_freed(objp
, c
->object_size
);
3786 __cache_free(c
, (void *)objp
, _RET_IP_
);
3787 local_irq_restore(flags
);
3789 EXPORT_SYMBOL(kfree
);
3792 * This initializes kmem_cache_node or resizes various caches for all nodes.
3794 static int setup_kmem_cache_nodes(struct kmem_cache
*cachep
, gfp_t gfp
)
3798 struct kmem_cache_node
*n
;
3800 for_each_online_node(node
) {
3801 ret
= setup_kmem_cache_node(cachep
, node
, gfp
, true);
3810 if (!cachep
->list
.next
) {
3811 /* Cache is not active yet. Roll back what we did */
3814 n
= get_node(cachep
, node
);
3817 free_alien_cache(n
->alien
);
3819 cachep
->node
[node
] = NULL
;
3827 /* Always called with the slab_mutex held */
3828 static int do_tune_cpucache(struct kmem_cache
*cachep
, int limit
,
3829 int batchcount
, int shared
, gfp_t gfp
)
3831 struct array_cache __percpu
*cpu_cache
, *prev
;
3834 cpu_cache
= alloc_kmem_cache_cpus(cachep
, limit
, batchcount
);
3838 prev
= cachep
->cpu_cache
;
3839 cachep
->cpu_cache
= cpu_cache
;
3841 * Without a previous cpu_cache there's no need to synchronize remote
3842 * cpus, so skip the IPIs.
3845 kick_all_cpus_sync();
3848 cachep
->batchcount
= batchcount
;
3849 cachep
->limit
= limit
;
3850 cachep
->shared
= shared
;
3855 for_each_online_cpu(cpu
) {
3858 struct kmem_cache_node
*n
;
3859 struct array_cache
*ac
= per_cpu_ptr(prev
, cpu
);
3861 node
= cpu_to_mem(cpu
);
3862 n
= get_node(cachep
, node
);
3863 spin_lock_irq(&n
->list_lock
);
3864 free_block(cachep
, ac
->entry
, ac
->avail
, node
, &list
);
3865 spin_unlock_irq(&n
->list_lock
);
3866 slabs_destroy(cachep
, &list
);
3871 return setup_kmem_cache_nodes(cachep
, gfp
);
3874 /* Called with slab_mutex held always */
3875 static int enable_cpucache(struct kmem_cache
*cachep
, gfp_t gfp
)
3882 err
= cache_random_seq_create(cachep
, cachep
->num
, gfp
);
3887 * The head array serves three purposes:
3888 * - create a LIFO ordering, i.e. return objects that are cache-warm
3889 * - reduce the number of spinlock operations.
3890 * - reduce the number of linked list operations on the slab and
3891 * bufctl chains: array operations are cheaper.
3892 * The numbers are guessed, we should auto-tune as described by
3895 if (cachep
->size
> 131072)
3897 else if (cachep
->size
> PAGE_SIZE
)
3899 else if (cachep
->size
> 1024)
3901 else if (cachep
->size
> 256)
3907 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3908 * allocation behaviour: Most allocs on one cpu, most free operations
3909 * on another cpu. For these cases, an efficient object passing between
3910 * cpus is necessary. This is provided by a shared array. The array
3911 * replaces Bonwick's magazine layer.
3912 * On uniprocessor, it's functionally equivalent (but less efficient)
3913 * to a larger limit. Thus disabled by default.
3916 if (cachep
->size
<= PAGE_SIZE
&& num_possible_cpus() > 1)
3921 * With debugging enabled, large batchcount lead to excessively long
3922 * periods with disabled local interrupts. Limit the batchcount
3927 batchcount
= (limit
+ 1) / 2;
3928 err
= do_tune_cpucache(cachep
, limit
, batchcount
, shared
, gfp
);
3931 pr_err("enable_cpucache failed for %s, error %d\n",
3932 cachep
->name
, -err
);
3937 * Drain an array if it contains any elements taking the node lock only if
3938 * necessary. Note that the node listlock also protects the array_cache
3939 * if drain_array() is used on the shared array.
3941 static void drain_array(struct kmem_cache
*cachep
, struct kmem_cache_node
*n
,
3942 struct array_cache
*ac
, int node
)
3946 /* ac from n->shared can be freed if we don't hold the slab_mutex. */
3947 check_mutex_acquired();
3949 if (!ac
|| !ac
->avail
)
3957 spin_lock_irq(&n
->list_lock
);
3958 drain_array_locked(cachep
, ac
, node
, false, &list
);
3959 spin_unlock_irq(&n
->list_lock
);
3961 slabs_destroy(cachep
, &list
);
3965 * cache_reap - Reclaim memory from caches.
3966 * @w: work descriptor
3968 * Called from workqueue/eventd every few seconds.
3970 * - clear the per-cpu caches for this CPU.
3971 * - return freeable pages to the main free memory pool.
3973 * If we cannot acquire the cache chain mutex then just give up - we'll try
3974 * again on the next iteration.
3976 static void cache_reap(struct work_struct
*w
)
3978 struct kmem_cache
*searchp
;
3979 struct kmem_cache_node
*n
;
3980 int node
= numa_mem_id();
3981 struct delayed_work
*work
= to_delayed_work(w
);
3983 if (!mutex_trylock(&slab_mutex
))
3984 /* Give up. Setup the next iteration. */
3987 list_for_each_entry(searchp
, &slab_caches
, list
) {
3991 * We only take the node lock if absolutely necessary and we
3992 * have established with reasonable certainty that
3993 * we can do some work if the lock was obtained.
3995 n
= get_node(searchp
, node
);
3997 reap_alien(searchp
, n
);
3999 drain_array(searchp
, n
, cpu_cache_get(searchp
), node
);
4002 * These are racy checks but it does not matter
4003 * if we skip one check or scan twice.
4005 if (time_after(n
->next_reap
, jiffies
))
4008 n
->next_reap
= jiffies
+ REAPTIMEOUT_NODE
;
4010 drain_array(searchp
, n
, n
->shared
, node
);
4012 if (n
->free_touched
)
4013 n
->free_touched
= 0;
4017 freed
= drain_freelist(searchp
, n
, (n
->free_limit
+
4018 5 * searchp
->num
- 1) / (5 * searchp
->num
));
4019 STATS_ADD_REAPED(searchp
, freed
);
4025 mutex_unlock(&slab_mutex
);
4028 /* Set up the next iteration */
4029 schedule_delayed_work_on(smp_processor_id(), work
,
4030 round_jiffies_relative(REAPTIMEOUT_AC
));
4033 void get_slabinfo(struct kmem_cache
*cachep
, struct slabinfo
*sinfo
)
4035 unsigned long active_objs
, num_objs
, active_slabs
;
4036 unsigned long total_slabs
= 0, free_objs
= 0, shared_avail
= 0;
4037 unsigned long free_slabs
= 0;
4039 struct kmem_cache_node
*n
;
4041 for_each_kmem_cache_node(cachep
, node
, n
) {
4043 spin_lock_irq(&n
->list_lock
);
4045 total_slabs
+= n
->total_slabs
;
4046 free_slabs
+= n
->free_slabs
;
4047 free_objs
+= n
->free_objects
;
4050 shared_avail
+= n
->shared
->avail
;
4052 spin_unlock_irq(&n
->list_lock
);
4054 num_objs
= total_slabs
* cachep
->num
;
4055 active_slabs
= total_slabs
- free_slabs
;
4056 active_objs
= num_objs
- free_objs
;
4058 sinfo
->active_objs
= active_objs
;
4059 sinfo
->num_objs
= num_objs
;
4060 sinfo
->active_slabs
= active_slabs
;
4061 sinfo
->num_slabs
= total_slabs
;
4062 sinfo
->shared_avail
= shared_avail
;
4063 sinfo
->limit
= cachep
->limit
;
4064 sinfo
->batchcount
= cachep
->batchcount
;
4065 sinfo
->shared
= cachep
->shared
;
4066 sinfo
->objects_per_slab
= cachep
->num
;
4067 sinfo
->cache_order
= cachep
->gfporder
;
4070 void slabinfo_show_stats(struct seq_file
*m
, struct kmem_cache
*cachep
)
4074 unsigned long high
= cachep
->high_mark
;
4075 unsigned long allocs
= cachep
->num_allocations
;
4076 unsigned long grown
= cachep
->grown
;
4077 unsigned long reaped
= cachep
->reaped
;
4078 unsigned long errors
= cachep
->errors
;
4079 unsigned long max_freeable
= cachep
->max_freeable
;
4080 unsigned long node_allocs
= cachep
->node_allocs
;
4081 unsigned long node_frees
= cachep
->node_frees
;
4082 unsigned long overflows
= cachep
->node_overflow
;
4084 seq_printf(m
, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu",
4085 allocs
, high
, grown
,
4086 reaped
, errors
, max_freeable
, node_allocs
,
4087 node_frees
, overflows
);
4091 unsigned long allochit
= atomic_read(&cachep
->allochit
);
4092 unsigned long allocmiss
= atomic_read(&cachep
->allocmiss
);
4093 unsigned long freehit
= atomic_read(&cachep
->freehit
);
4094 unsigned long freemiss
= atomic_read(&cachep
->freemiss
);
4096 seq_printf(m
, " : cpustat %6lu %6lu %6lu %6lu",
4097 allochit
, allocmiss
, freehit
, freemiss
);
4102 #define MAX_SLABINFO_WRITE 128
4104 * slabinfo_write - Tuning for the slab allocator
4106 * @buffer: user buffer
4107 * @count: data length
4110 * Return: %0 on success, negative error code otherwise.
4112 ssize_t
slabinfo_write(struct file
*file
, const char __user
*buffer
,
4113 size_t count
, loff_t
*ppos
)
4115 char kbuf
[MAX_SLABINFO_WRITE
+ 1], *tmp
;
4116 int limit
, batchcount
, shared
, res
;
4117 struct kmem_cache
*cachep
;
4119 if (count
> MAX_SLABINFO_WRITE
)
4121 if (copy_from_user(&kbuf
, buffer
, count
))
4123 kbuf
[MAX_SLABINFO_WRITE
] = '\0';
4125 tmp
= strchr(kbuf
, ' ');
4130 if (sscanf(tmp
, " %d %d %d", &limit
, &batchcount
, &shared
) != 3)
4133 /* Find the cache in the chain of caches. */
4134 mutex_lock(&slab_mutex
);
4136 list_for_each_entry(cachep
, &slab_caches
, list
) {
4137 if (!strcmp(cachep
->name
, kbuf
)) {
4138 if (limit
< 1 || batchcount
< 1 ||
4139 batchcount
> limit
|| shared
< 0) {
4142 res
= do_tune_cpucache(cachep
, limit
,
4149 mutex_unlock(&slab_mutex
);
4155 #ifdef CONFIG_HARDENED_USERCOPY
4157 * Rejects incorrectly sized objects and objects that are to be copied
4158 * to/from userspace but do not fall entirely within the containing slab
4159 * cache's usercopy region.
4161 * Returns NULL if check passes, otherwise const char * to name of cache
4162 * to indicate an error.
4164 void __check_heap_object(const void *ptr
, unsigned long n
,
4165 const struct slab
*slab
, bool to_user
)
4167 struct kmem_cache
*cachep
;
4169 unsigned long offset
;
4171 ptr
= kasan_reset_tag(ptr
);
4173 /* Find and validate object. */
4174 cachep
= slab
->slab_cache
;
4175 objnr
= obj_to_index(cachep
, slab
, (void *)ptr
);
4176 BUG_ON(objnr
>= cachep
->num
);
4178 /* Find offset within object. */
4179 if (is_kfence_address(ptr
))
4180 offset
= ptr
- kfence_object_start(ptr
);
4182 offset
= ptr
- index_to_obj(cachep
, slab
, objnr
) - obj_offset(cachep
);
4184 /* Allow address range falling entirely within usercopy region. */
4185 if (offset
>= cachep
->useroffset
&&
4186 offset
- cachep
->useroffset
<= cachep
->usersize
&&
4187 n
<= cachep
->useroffset
- offset
+ cachep
->usersize
)
4190 usercopy_abort("SLAB object", cachep
->name
, to_user
, offset
, n
);
4192 #endif /* CONFIG_HARDENED_USERCOPY */
4195 * __ksize -- Uninstrumented ksize.
4196 * @objp: pointer to the object
4198 * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
4199 * safety checks as ksize() with KASAN instrumentation enabled.
4201 * Return: size of the actual memory used by @objp in bytes
4203 size_t __ksize(const void *objp
)
4205 struct kmem_cache
*c
;
4209 if (unlikely(objp
== ZERO_SIZE_PTR
))
4212 c
= virt_to_cache(objp
);
4213 size
= c
? c
->object_size
: 0;
4217 EXPORT_SYMBOL(__ksize
);