1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/mm/slab.c
4 * Written by Mark Hemment, 1996/97.
5 * (markhe@nextd.demon.co.uk)
6 *
7 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
8 *
9 * Major cleanup, different bufctl logic, per-cpu arrays
10 * (c) 2000 Manfred Spraul
11 *
12 * Cleanup, make the head arrays unconditional, preparation for NUMA
13 * (c) 2002 Manfred Spraul
14 *
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
22 *
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.
28 *
29 * This means, that your constructor is used only for newly allocated
30 * slabs and you must pass objects with the same initializations to
31 * kmem_cache_free.
32 *
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.
36 *
37 * In order to reduce fragmentation, the slabs are sorted in 3 groups:
38 * full slabs with 0 free objects
39 * partial slabs
40 * empty slabs with no allocated objects
41 *
42 * If partial slabs exist, then new allocations come from these slabs,
43 * otherwise from empty slabs or new slabs are allocated.
44 *
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.
47 *
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.
53 *
54 * The c_cpuarray may not be read with enabled local interrupts -
55 * it's changed with a smp_call_function().
56 *
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.
64 *
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
67 * his patch.
68 *
69 * Further notes from the original documentation:
70 *
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()).
76 *
77 * At present, each engine can be growing a cache. This should be blocked.
78 *
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>
84 *
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.
88 */
89
90 #include <linux/slab.h>
91 #include <linux/mm.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>
121
122 #include <net/sock.h>
123
124 #include <asm/cacheflush.h>
125 #include <asm/tlbflush.h>
126 #include <asm/page.h>
127
128 #include <trace/events/kmem.h>
129
130 #include "internal.h"
131
132 #include "slab.h"
133
134 /*
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).
137 *
138 * STATS - 1 to collect stats for /proc/slabinfo.
139 * 0 for faster, smaller code (especially in the critical paths).
140 *
141 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
142 */
143
144 #ifdef CONFIG_DEBUG_SLAB
145 #define DEBUG 1
146 #define STATS 1
147 #define FORCED_DEBUG 1
148 #else
149 #define DEBUG 0
150 #define STATS 0
151 #define FORCED_DEBUG 0
152 #endif
153
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))
157
158 #ifndef ARCH_KMALLOC_FLAGS
159 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
160 #endif
161
162 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \
163 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0)
164
165 #if FREELIST_BYTE_INDEX
166 typedef unsigned char freelist_idx_t;
167 #else
168 typedef unsigned short freelist_idx_t;
169 #endif
170
171 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1)
172
173 /*
174 * struct array_cache
175 *
176 * Purpose:
177 * - LIFO ordering, to hand out cache-warm objects from _alloc
178 * - reduce the number of linked list operations
179 * - reduce spinlock operations
180 *
181 * The limit is stored in the per-cpu structure to reduce the data cache
182 * footprint.
183 *
184 */
185 struct array_cache {
186 unsigned int avail;
187 unsigned int limit;
188 unsigned int batchcount;
189 unsigned int touched;
190 void *entry[]; /*
191 * Must have this definition in here for the proper
192 * alignment of array_cache. Also simplifies accessing
193 * the entries.
194 */
195 };
196
197 struct alien_cache {
198 spinlock_t lock;
199 struct array_cache ac;
200 };
201
202 /*
203 * Need this for bootstrapping a per node allocator.
204 */
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)
209
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);
217
218 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
219 void **list);
220 static inline void fixup_slab_list(struct kmem_cache *cachep,
221 struct kmem_cache_node *n, struct page *page,
222 void **list);
223 static int slab_early_init = 1;
224
225 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node))
226
kmem_cache_node_init(struct kmem_cache_node * parent)227 static void kmem_cache_node_init(struct kmem_cache_node *parent)
228 {
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;
240 }
241
242 #define MAKE_LIST(cachep, listp, slab, nodeid) \
243 do { \
244 INIT_LIST_HEAD(listp); \
245 list_splice(&get_node(cachep, nodeid)->slab, listp); \
246 } while (0)
247
248 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
249 do { \
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); \
253 } while (0)
254
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)
259
260 #define BATCHREFILL_LIMIT 16
261 /*
262 * Optimization question: fewer reaps means less probability for unnessary
263 * cpucache drain/refill cycles.
264 *
265 * OTOH the cpuarrays can contain lots of objects,
266 * which could lock up otherwise freeable slabs.
267 */
268 #define REAPTIMEOUT_AC (2*HZ)
269 #define REAPTIMEOUT_NODE (4*HZ)
270
271 #if STATS
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) \
278 do { \
279 if ((x)->num_active > (x)->high_mark) \
280 (x)->high_mark = (x)->num_active; \
281 } while (0)
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) \
287 do { \
288 if ((x)->max_freeable < i) \
289 (x)->max_freeable = i; \
290 } while (0)
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)
295 #else
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)
311 #endif
312
313 #if DEBUG
314
315 /*
316 * memory layout of objects:
317 * 0 : objp
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:
322 * redzone word.
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]
327 */
obj_offset(struct kmem_cache * cachep)328 static int obj_offset(struct kmem_cache *cachep)
329 {
330 return cachep->obj_offset;
331 }
332
dbg_redzone1(struct kmem_cache * cachep,void * objp)333 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
334 {
335 BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
336 return (unsigned long long*) (objp + obj_offset(cachep) -
337 sizeof(unsigned long long));
338 }
339
dbg_redzone2(struct kmem_cache * cachep,void * objp)340 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
341 {
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) -
346 REDZONE_ALIGN);
347 return (unsigned long long *) (objp + cachep->size -
348 sizeof(unsigned long long));
349 }
350
dbg_userword(struct kmem_cache * cachep,void * objp)351 static void **dbg_userword(struct kmem_cache *cachep, void *objp)
352 {
353 BUG_ON(!(cachep->flags & SLAB_STORE_USER));
354 return (void **)(objp + cachep->size - BYTES_PER_WORD);
355 }
356
357 #else
358
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;})
363
364 #endif
365
366 /*
367 * Do not go above this order unless 0 objects fit into the slab or
368 * overridden on the command line.
369 */
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;
374
index_to_obj(struct kmem_cache * cache,struct page * page,unsigned int idx)375 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page,
376 unsigned int idx)
377 {
378 return page->s_mem + cache->size * idx;
379 }
380
381 #define BOOT_CPUCACHE_ENTRIES 1
382 /* internal cache of cache description objs */
383 static struct kmem_cache kmem_cache_boot = {
384 .batchcount = 1,
385 .limit = BOOT_CPUCACHE_ENTRIES,
386 .shared = 1,
387 .size = sizeof(struct kmem_cache),
388 .name = "kmem_cache",
389 };
390
391 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
392
cpu_cache_get(struct kmem_cache * cachep)393 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
394 {
395 return this_cpu_ptr(cachep->cpu_cache);
396 }
397
398 /*
399 * Calculate the number of objects and left-over bytes for a given buffer size.
400 */
cache_estimate(unsigned long gfporder,size_t buffer_size,slab_flags_t flags,size_t * left_over)401 static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size,
402 slab_flags_t flags, size_t *left_over)
403 {
404 unsigned int num;
405 size_t slab_size = PAGE_SIZE << gfporder;
406
407 /*
408 * The slab management structure can be either off the slab or
409 * on it. For the latter case, the memory allocated for a
410 * slab is used for:
411 *
412 * - @buffer_size bytes for each object
413 * - One freelist_idx_t for each object
414 *
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.
418 *
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.
423 */
424 if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) {
425 num = slab_size / buffer_size;
426 *left_over = slab_size % buffer_size;
427 } else {
428 num = slab_size / (buffer_size + sizeof(freelist_idx_t));
429 *left_over = slab_size %
430 (buffer_size + sizeof(freelist_idx_t));
431 }
432
433 return num;
434 }
435
436 #if DEBUG
437 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
438
__slab_error(const char * function,struct kmem_cache * cachep,char * msg)439 static void __slab_error(const char *function, struct kmem_cache *cachep,
440 char *msg)
441 {
442 pr_err("slab error in %s(): cache `%s': %s\n",
443 function, cachep->name, msg);
444 dump_stack();
445 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
446 }
447 #endif
448
449 /*
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
454 * line
455 */
456
457 static int use_alien_caches __read_mostly = 1;
noaliencache_setup(char * s)458 static int __init noaliencache_setup(char *s)
459 {
460 use_alien_caches = 0;
461 return 1;
462 }
463 __setup("noaliencache", noaliencache_setup);
464
slab_max_order_setup(char * str)465 static int __init slab_max_order_setup(char *str)
466 {
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;
471
472 return 1;
473 }
474 __setup("slab_max_order=", slab_max_order_setup);
475
476 #ifdef CONFIG_NUMA
477 /*
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.
482 */
483 static DEFINE_PER_CPU(unsigned long, slab_reap_node);
484
init_reap_node(int cpu)485 static void init_reap_node(int cpu)
486 {
487 per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu),
488 node_online_map);
489 }
490
next_reap_node(void)491 static void next_reap_node(void)
492 {
493 int node = __this_cpu_read(slab_reap_node);
494
495 node = next_node_in(node, node_online_map);
496 __this_cpu_write(slab_reap_node, node);
497 }
498
499 #else
500 #define init_reap_node(cpu) do { } while (0)
501 #define next_reap_node(void) do { } while (0)
502 #endif
503
504 /*
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
509 * lock.
510 */
start_cpu_timer(int cpu)511 static void start_cpu_timer(int cpu)
512 {
513 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu);
514
515 if (reap_work->work.func == NULL) {
516 init_reap_node(cpu);
517 INIT_DEFERRABLE_WORK(reap_work, cache_reap);
518 schedule_delayed_work_on(cpu, reap_work,
519 __round_jiffies_relative(HZ, cpu));
520 }
521 }
522
init_arraycache(struct array_cache * ac,int limit,int batch)523 static void init_arraycache(struct array_cache *ac, int limit, int batch)
524 {
525 if (ac) {
526 ac->avail = 0;
527 ac->limit = limit;
528 ac->batchcount = batch;
529 ac->touched = 0;
530 }
531 }
532
alloc_arraycache(int node,int entries,int batchcount,gfp_t gfp)533 static struct array_cache *alloc_arraycache(int node, int entries,
534 int batchcount, gfp_t gfp)
535 {
536 size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache);
537 struct array_cache *ac = NULL;
538
539 ac = kmalloc_node(memsize, gfp, node);
540 /*
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.
546 */
547 kmemleak_no_scan(ac);
548 init_arraycache(ac, entries, batchcount);
549 return ac;
550 }
551
cache_free_pfmemalloc(struct kmem_cache * cachep,struct page * page,void * objp)552 static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep,
553 struct page *page, void *objp)
554 {
555 struct kmem_cache_node *n;
556 int page_node;
557 LIST_HEAD(list);
558
559 page_node = page_to_nid(page);
560 n = get_node(cachep, page_node);
561
562 spin_lock(&n->list_lock);
563 free_block(cachep, &objp, 1, page_node, &list);
564 spin_unlock(&n->list_lock);
565
566 slabs_destroy(cachep, &list);
567 }
568
569 /*
570 * Transfer objects in one arraycache to another.
571 * Locking must be handled by the caller.
572 *
573 * Return the number of entries transferred.
574 */
transfer_objects(struct array_cache * to,struct array_cache * from,unsigned int max)575 static int transfer_objects(struct array_cache *to,
576 struct array_cache *from, unsigned int max)
577 {
578 /* Figure out how many entries to transfer */
579 int nr = min3(from->avail, max, to->limit - to->avail);
580
581 if (!nr)
582 return 0;
583
584 memcpy(to->entry + to->avail, from->entry + from->avail -nr,
585 sizeof(void *) *nr);
586
587 from->avail -= nr;
588 to->avail += nr;
589 return nr;
590 }
591
592 /* &alien->lock must be held by alien callers. */
__free_one(struct array_cache * ac,void * objp)593 static __always_inline void __free_one(struct array_cache *ac, void *objp)
594 {
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))
598 return;
599 ac->entry[ac->avail++] = objp;
600 }
601
602 #ifndef CONFIG_NUMA
603
604 #define drain_alien_cache(cachep, alien) do { } while (0)
605 #define reap_alien(cachep, n) do { } while (0)
606
alloc_alien_cache(int node,int limit,gfp_t gfp)607 static inline struct alien_cache **alloc_alien_cache(int node,
608 int limit, gfp_t gfp)
609 {
610 return NULL;
611 }
612
free_alien_cache(struct alien_cache ** ac_ptr)613 static inline void free_alien_cache(struct alien_cache **ac_ptr)
614 {
615 }
616
cache_free_alien(struct kmem_cache * cachep,void * objp)617 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
618 {
619 return 0;
620 }
621
alternate_node_alloc(struct kmem_cache * cachep,gfp_t flags)622 static inline void *alternate_node_alloc(struct kmem_cache *cachep,
623 gfp_t flags)
624 {
625 return NULL;
626 }
627
____cache_alloc_node(struct kmem_cache * cachep,gfp_t flags,int nodeid)628 static inline void *____cache_alloc_node(struct kmem_cache *cachep,
629 gfp_t flags, int nodeid)
630 {
631 return NULL;
632 }
633
gfp_exact_node(gfp_t flags)634 static inline gfp_t gfp_exact_node(gfp_t flags)
635 {
636 return flags & ~__GFP_NOFAIL;
637 }
638
639 #else /* CONFIG_NUMA */
640
641 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
642 static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
643
__alloc_alien_cache(int node,int entries,int batch,gfp_t gfp)644 static struct alien_cache *__alloc_alien_cache(int node, int entries,
645 int batch, gfp_t gfp)
646 {
647 size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache);
648 struct alien_cache *alc = NULL;
649
650 alc = kmalloc_node(memsize, gfp, node);
651 if (alc) {
652 kmemleak_no_scan(alc);
653 init_arraycache(&alc->ac, entries, batch);
654 spin_lock_init(&alc->lock);
655 }
656 return alc;
657 }
658
alloc_alien_cache(int node,int limit,gfp_t gfp)659 static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
660 {
661 struct alien_cache **alc_ptr;
662 int i;
663
664 if (limit > 1)
665 limit = 12;
666 alc_ptr = kcalloc_node(nr_node_ids, sizeof(void *), gfp, node);
667 if (!alc_ptr)
668 return NULL;
669
670 for_each_node(i) {
671 if (i == node || !node_online(i))
672 continue;
673 alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp);
674 if (!alc_ptr[i]) {
675 for (i--; i >= 0; i--)
676 kfree(alc_ptr[i]);
677 kfree(alc_ptr);
678 return NULL;
679 }
680 }
681 return alc_ptr;
682 }
683
free_alien_cache(struct alien_cache ** alc_ptr)684 static void free_alien_cache(struct alien_cache **alc_ptr)
685 {
686 int i;
687
688 if (!alc_ptr)
689 return;
690 for_each_node(i)
691 kfree(alc_ptr[i]);
692 kfree(alc_ptr);
693 }
694
__drain_alien_cache(struct kmem_cache * cachep,struct array_cache * ac,int node,struct list_head * list)695 static void __drain_alien_cache(struct kmem_cache *cachep,
696 struct array_cache *ac, int node,
697 struct list_head *list)
698 {
699 struct kmem_cache_node *n = get_node(cachep, node);
700
701 if (ac->avail) {
702 spin_lock(&n->list_lock);
703 /*
704 * Stuff objects into the remote nodes shared array first.
705 * That way we could avoid the overhead of putting the objects
706 * into the free lists and getting them back later.
707 */
708 if (n->shared)
709 transfer_objects(n->shared, ac, ac->limit);
710
711 free_block(cachep, ac->entry, ac->avail, node, list);
712 ac->avail = 0;
713 spin_unlock(&n->list_lock);
714 }
715 }
716
717 /*
718 * Called from cache_reap() to regularly drain alien caches round robin.
719 */
reap_alien(struct kmem_cache * cachep,struct kmem_cache_node * n)720 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n)
721 {
722 int node = __this_cpu_read(slab_reap_node);
723
724 if (n->alien) {
725 struct alien_cache *alc = n->alien[node];
726 struct array_cache *ac;
727
728 if (alc) {
729 ac = &alc->ac;
730 if (ac->avail && spin_trylock_irq(&alc->lock)) {
731 LIST_HEAD(list);
732
733 __drain_alien_cache(cachep, ac, node, &list);
734 spin_unlock_irq(&alc->lock);
735 slabs_destroy(cachep, &list);
736 }
737 }
738 }
739 }
740
drain_alien_cache(struct kmem_cache * cachep,struct alien_cache ** alien)741 static void drain_alien_cache(struct kmem_cache *cachep,
742 struct alien_cache **alien)
743 {
744 int i = 0;
745 struct alien_cache *alc;
746 struct array_cache *ac;
747 unsigned long flags;
748
749 for_each_online_node(i) {
750 alc = alien[i];
751 if (alc) {
752 LIST_HEAD(list);
753
754 ac = &alc->ac;
755 spin_lock_irqsave(&alc->lock, flags);
756 __drain_alien_cache(cachep, ac, i, &list);
757 spin_unlock_irqrestore(&alc->lock, flags);
758 slabs_destroy(cachep, &list);
759 }
760 }
761 }
762
__cache_free_alien(struct kmem_cache * cachep,void * objp,int node,int page_node)763 static int __cache_free_alien(struct kmem_cache *cachep, void *objp,
764 int node, int page_node)
765 {
766 struct kmem_cache_node *n;
767 struct alien_cache *alien = NULL;
768 struct array_cache *ac;
769 LIST_HEAD(list);
770
771 n = get_node(cachep, node);
772 STATS_INC_NODEFREES(cachep);
773 if (n->alien && n->alien[page_node]) {
774 alien = n->alien[page_node];
775 ac = &alien->ac;
776 spin_lock(&alien->lock);
777 if (unlikely(ac->avail == ac->limit)) {
778 STATS_INC_ACOVERFLOW(cachep);
779 __drain_alien_cache(cachep, ac, page_node, &list);
780 }
781 __free_one(ac, objp);
782 spin_unlock(&alien->lock);
783 slabs_destroy(cachep, &list);
784 } else {
785 n = get_node(cachep, page_node);
786 spin_lock(&n->list_lock);
787 free_block(cachep, &objp, 1, page_node, &list);
788 spin_unlock(&n->list_lock);
789 slabs_destroy(cachep, &list);
790 }
791 return 1;
792 }
793
cache_free_alien(struct kmem_cache * cachep,void * objp)794 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
795 {
796 int page_node = page_to_nid(virt_to_page(objp));
797 int node = numa_mem_id();
798 /*
799 * Make sure we are not freeing a object from another node to the array
800 * cache on this cpu.
801 */
802 if (likely(node == page_node))
803 return 0;
804
805 return __cache_free_alien(cachep, objp, node, page_node);
806 }
807
808 /*
809 * Construct gfp mask to allocate from a specific node but do not reclaim or
810 * warn about failures.
811 */
gfp_exact_node(gfp_t flags)812 static inline gfp_t gfp_exact_node(gfp_t flags)
813 {
814 return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL);
815 }
816 #endif
817
init_cache_node(struct kmem_cache * cachep,int node,gfp_t gfp)818 static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp)
819 {
820 struct kmem_cache_node *n;
821
822 /*
823 * Set up the kmem_cache_node for cpu before we can
824 * begin anything. Make sure some other cpu on this
825 * node has not already allocated this
826 */
827 n = get_node(cachep, node);
828 if (n) {
829 spin_lock_irq(&n->list_lock);
830 n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount +
831 cachep->num;
832 spin_unlock_irq(&n->list_lock);
833
834 return 0;
835 }
836
837 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node);
838 if (!n)
839 return -ENOMEM;
840
841 kmem_cache_node_init(n);
842 n->next_reap = jiffies + REAPTIMEOUT_NODE +
843 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
844
845 n->free_limit =
846 (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num;
847
848 /*
849 * The kmem_cache_nodes don't come and go as CPUs
850 * come and go. slab_mutex is sufficient
851 * protection here.
852 */
853 cachep->node[node] = n;
854
855 return 0;
856 }
857
858 #if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP)
859 /*
860 * Allocates and initializes node for a node on each slab cache, used for
861 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node
862 * will be allocated off-node since memory is not yet online for the new node.
863 * When hotplugging memory or a cpu, existing node are not replaced if
864 * already in use.
865 *
866 * Must hold slab_mutex.
867 */
init_cache_node_node(int node)868 static int init_cache_node_node(int node)
869 {
870 int ret;
871 struct kmem_cache *cachep;
872
873 list_for_each_entry(cachep, &slab_caches, list) {
874 ret = init_cache_node(cachep, node, GFP_KERNEL);
875 if (ret)
876 return ret;
877 }
878
879 return 0;
880 }
881 #endif
882
setup_kmem_cache_node(struct kmem_cache * cachep,int node,gfp_t gfp,bool force_change)883 static int setup_kmem_cache_node(struct kmem_cache *cachep,
884 int node, gfp_t gfp, bool force_change)
885 {
886 int ret = -ENOMEM;
887 struct kmem_cache_node *n;
888 struct array_cache *old_shared = NULL;
889 struct array_cache *new_shared = NULL;
890 struct alien_cache **new_alien = NULL;
891 LIST_HEAD(list);
892
893 if (use_alien_caches) {
894 new_alien = alloc_alien_cache(node, cachep->limit, gfp);
895 if (!new_alien)
896 goto fail;
897 }
898
899 if (cachep->shared) {
900 new_shared = alloc_arraycache(node,
901 cachep->shared * cachep->batchcount, 0xbaadf00d, gfp);
902 if (!new_shared)
903 goto fail;
904 }
905
906 ret = init_cache_node(cachep, node, gfp);
907 if (ret)
908 goto fail;
909
910 n = get_node(cachep, node);
911 spin_lock_irq(&n->list_lock);
912 if (n->shared && force_change) {
913 free_block(cachep, n->shared->entry,
914 n->shared->avail, node, &list);
915 n->shared->avail = 0;
916 }
917
918 if (!n->shared || force_change) {
919 old_shared = n->shared;
920 n->shared = new_shared;
921 new_shared = NULL;
922 }
923
924 if (!n->alien) {
925 n->alien = new_alien;
926 new_alien = NULL;
927 }
928
929 spin_unlock_irq(&n->list_lock);
930 slabs_destroy(cachep, &list);
931
932 /*
933 * To protect lockless access to n->shared during irq disabled context.
934 * If n->shared isn't NULL in irq disabled context, accessing to it is
935 * guaranteed to be valid until irq is re-enabled, because it will be
936 * freed after synchronize_rcu().
937 */
938 if (old_shared && force_change)
939 synchronize_rcu();
940
941 fail:
942 kfree(old_shared);
943 kfree(new_shared);
944 free_alien_cache(new_alien);
945
946 return ret;
947 }
948
949 #ifdef CONFIG_SMP
950
cpuup_canceled(long cpu)951 static void cpuup_canceled(long cpu)
952 {
953 struct kmem_cache *cachep;
954 struct kmem_cache_node *n = NULL;
955 int node = cpu_to_mem(cpu);
956 const struct cpumask *mask = cpumask_of_node(node);
957
958 list_for_each_entry(cachep, &slab_caches, list) {
959 struct array_cache *nc;
960 struct array_cache *shared;
961 struct alien_cache **alien;
962 LIST_HEAD(list);
963
964 n = get_node(cachep, node);
965 if (!n)
966 continue;
967
968 spin_lock_irq(&n->list_lock);
969
970 /* Free limit for this kmem_cache_node */
971 n->free_limit -= cachep->batchcount;
972
973 /* cpu is dead; no one can alloc from it. */
974 nc = per_cpu_ptr(cachep->cpu_cache, cpu);
975 free_block(cachep, nc->entry, nc->avail, node, &list);
976 nc->avail = 0;
977
978 if (!cpumask_empty(mask)) {
979 spin_unlock_irq(&n->list_lock);
980 goto free_slab;
981 }
982
983 shared = n->shared;
984 if (shared) {
985 free_block(cachep, shared->entry,
986 shared->avail, node, &list);
987 n->shared = NULL;
988 }
989
990 alien = n->alien;
991 n->alien = NULL;
992
993 spin_unlock_irq(&n->list_lock);
994
995 kfree(shared);
996 if (alien) {
997 drain_alien_cache(cachep, alien);
998 free_alien_cache(alien);
999 }
1000
1001 free_slab:
1002 slabs_destroy(cachep, &list);
1003 }
1004 /*
1005 * In the previous loop, all the objects were freed to
1006 * the respective cache's slabs, now we can go ahead and
1007 * shrink each nodelist to its limit.
1008 */
1009 list_for_each_entry(cachep, &slab_caches, list) {
1010 n = get_node(cachep, node);
1011 if (!n)
1012 continue;
1013 drain_freelist(cachep, n, INT_MAX);
1014 }
1015 }
1016
cpuup_prepare(long cpu)1017 static int cpuup_prepare(long cpu)
1018 {
1019 struct kmem_cache *cachep;
1020 int node = cpu_to_mem(cpu);
1021 int err;
1022
1023 /*
1024 * We need to do this right in the beginning since
1025 * alloc_arraycache's are going to use this list.
1026 * kmalloc_node allows us to add the slab to the right
1027 * kmem_cache_node and not this cpu's kmem_cache_node
1028 */
1029 err = init_cache_node_node(node);
1030 if (err < 0)
1031 goto bad;
1032
1033 /*
1034 * Now we can go ahead with allocating the shared arrays and
1035 * array caches
1036 */
1037 list_for_each_entry(cachep, &slab_caches, list) {
1038 err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false);
1039 if (err)
1040 goto bad;
1041 }
1042
1043 return 0;
1044 bad:
1045 cpuup_canceled(cpu);
1046 return -ENOMEM;
1047 }
1048
slab_prepare_cpu(unsigned int cpu)1049 int slab_prepare_cpu(unsigned int cpu)
1050 {
1051 int err;
1052
1053 mutex_lock(&slab_mutex);
1054 err = cpuup_prepare(cpu);
1055 mutex_unlock(&slab_mutex);
1056 return err;
1057 }
1058
1059 /*
1060 * This is called for a failed online attempt and for a successful
1061 * offline.
1062 *
1063 * Even if all the cpus of a node are down, we don't free the
1064 * kmem_cache_node of any cache. This to avoid a race between cpu_down, and
1065 * a kmalloc allocation from another cpu for memory from the node of
1066 * the cpu going down. The kmem_cache_node structure is usually allocated from
1067 * kmem_cache_create() and gets destroyed at kmem_cache_destroy().
1068 */
slab_dead_cpu(unsigned int cpu)1069 int slab_dead_cpu(unsigned int cpu)
1070 {
1071 mutex_lock(&slab_mutex);
1072 cpuup_canceled(cpu);
1073 mutex_unlock(&slab_mutex);
1074 return 0;
1075 }
1076 #endif
1077
slab_online_cpu(unsigned int cpu)1078 static int slab_online_cpu(unsigned int cpu)
1079 {
1080 start_cpu_timer(cpu);
1081 return 0;
1082 }
1083
slab_offline_cpu(unsigned int cpu)1084 static int slab_offline_cpu(unsigned int cpu)
1085 {
1086 /*
1087 * Shutdown cache reaper. Note that the slab_mutex is held so
1088 * that if cache_reap() is invoked it cannot do anything
1089 * expensive but will only modify reap_work and reschedule the
1090 * timer.
1091 */
1092 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
1093 /* Now the cache_reaper is guaranteed to be not running. */
1094 per_cpu(slab_reap_work, cpu).work.func = NULL;
1095 return 0;
1096 }
1097
1098 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
1099 /*
1100 * Drains freelist for a node on each slab cache, used for memory hot-remove.
1101 * Returns -EBUSY if all objects cannot be drained so that the node is not
1102 * removed.
1103 *
1104 * Must hold slab_mutex.
1105 */
drain_cache_node_node(int node)1106 static int __meminit drain_cache_node_node(int node)
1107 {
1108 struct kmem_cache *cachep;
1109 int ret = 0;
1110
1111 list_for_each_entry(cachep, &slab_caches, list) {
1112 struct kmem_cache_node *n;
1113
1114 n = get_node(cachep, node);
1115 if (!n)
1116 continue;
1117
1118 drain_freelist(cachep, n, INT_MAX);
1119
1120 if (!list_empty(&n->slabs_full) ||
1121 !list_empty(&n->slabs_partial)) {
1122 ret = -EBUSY;
1123 break;
1124 }
1125 }
1126 return ret;
1127 }
1128
slab_memory_callback(struct notifier_block * self,unsigned long action,void * arg)1129 static int __meminit slab_memory_callback(struct notifier_block *self,
1130 unsigned long action, void *arg)
1131 {
1132 struct memory_notify *mnb = arg;
1133 int ret = 0;
1134 int nid;
1135
1136 nid = mnb->status_change_nid;
1137 if (nid < 0)
1138 goto out;
1139
1140 switch (action) {
1141 case MEM_GOING_ONLINE:
1142 mutex_lock(&slab_mutex);
1143 ret = init_cache_node_node(nid);
1144 mutex_unlock(&slab_mutex);
1145 break;
1146 case MEM_GOING_OFFLINE:
1147 mutex_lock(&slab_mutex);
1148 ret = drain_cache_node_node(nid);
1149 mutex_unlock(&slab_mutex);
1150 break;
1151 case MEM_ONLINE:
1152 case MEM_OFFLINE:
1153 case MEM_CANCEL_ONLINE:
1154 case MEM_CANCEL_OFFLINE:
1155 break;
1156 }
1157 out:
1158 return notifier_from_errno(ret);
1159 }
1160 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
1161
1162 /*
1163 * swap the static kmem_cache_node with kmalloced memory
1164 */
init_list(struct kmem_cache * cachep,struct kmem_cache_node * list,int nodeid)1165 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list,
1166 int nodeid)
1167 {
1168 struct kmem_cache_node *ptr;
1169
1170 ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid);
1171 BUG_ON(!ptr);
1172
1173 memcpy(ptr, list, sizeof(struct kmem_cache_node));
1174 /*
1175 * Do not assume that spinlocks can be initialized via memcpy:
1176 */
1177 spin_lock_init(&ptr->list_lock);
1178
1179 MAKE_ALL_LISTS(cachep, ptr, nodeid);
1180 cachep->node[nodeid] = ptr;
1181 }
1182
1183 /*
1184 * For setting up all the kmem_cache_node for cache whose buffer_size is same as
1185 * size of kmem_cache_node.
1186 */
set_up_node(struct kmem_cache * cachep,int index)1187 static void __init set_up_node(struct kmem_cache *cachep, int index)
1188 {
1189 int node;
1190
1191 for_each_online_node(node) {
1192 cachep->node[node] = &init_kmem_cache_node[index + node];
1193 cachep->node[node]->next_reap = jiffies +
1194 REAPTIMEOUT_NODE +
1195 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1196 }
1197 }
1198
1199 /*
1200 * Initialisation. Called after the page allocator have been initialised and
1201 * before smp_init().
1202 */
kmem_cache_init(void)1203 void __init kmem_cache_init(void)
1204 {
1205 int i;
1206
1207 kmem_cache = &kmem_cache_boot;
1208
1209 if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1)
1210 use_alien_caches = 0;
1211
1212 for (i = 0; i < NUM_INIT_LISTS; i++)
1213 kmem_cache_node_init(&init_kmem_cache_node[i]);
1214
1215 /*
1216 * Fragmentation resistance on low memory - only use bigger
1217 * page orders on machines with more than 32MB of memory if
1218 * not overridden on the command line.
1219 */
1220 if (!slab_max_order_set && totalram_pages() > (32 << 20) >> PAGE_SHIFT)
1221 slab_max_order = SLAB_MAX_ORDER_HI;
1222
1223 /* Bootstrap is tricky, because several objects are allocated
1224 * from caches that do not exist yet:
1225 * 1) initialize the kmem_cache cache: it contains the struct
1226 * kmem_cache structures of all caches, except kmem_cache itself:
1227 * kmem_cache is statically allocated.
1228 * Initially an __init data area is used for the head array and the
1229 * kmem_cache_node structures, it's replaced with a kmalloc allocated
1230 * array at the end of the bootstrap.
1231 * 2) Create the first kmalloc cache.
1232 * The struct kmem_cache for the new cache is allocated normally.
1233 * An __init data area is used for the head array.
1234 * 3) Create the remaining kmalloc caches, with minimally sized
1235 * head arrays.
1236 * 4) Replace the __init data head arrays for kmem_cache and the first
1237 * kmalloc cache with kmalloc allocated arrays.
1238 * 5) Replace the __init data for kmem_cache_node for kmem_cache and
1239 * the other cache's with kmalloc allocated memory.
1240 * 6) Resize the head arrays of the kmalloc caches to their final sizes.
1241 */
1242
1243 /* 1) create the kmem_cache */
1244
1245 /*
1246 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
1247 */
1248 create_boot_cache(kmem_cache, "kmem_cache",
1249 offsetof(struct kmem_cache, node) +
1250 nr_node_ids * sizeof(struct kmem_cache_node *),
1251 SLAB_HWCACHE_ALIGN, 0, 0);
1252 list_add(&kmem_cache->list, &slab_caches);
1253 slab_state = PARTIAL;
1254
1255 /*
1256 * Initialize the caches that provide memory for the kmem_cache_node
1257 * structures first. Without this, further allocations will bug.
1258 */
1259 kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE] = create_kmalloc_cache(
1260 kmalloc_info[INDEX_NODE].name[KMALLOC_NORMAL],
1261 kmalloc_info[INDEX_NODE].size,
1262 ARCH_KMALLOC_FLAGS, 0,
1263 kmalloc_info[INDEX_NODE].size);
1264 slab_state = PARTIAL_NODE;
1265 setup_kmalloc_cache_index_table();
1266
1267 slab_early_init = 0;
1268
1269 /* 5) Replace the bootstrap kmem_cache_node */
1270 {
1271 int nid;
1272
1273 for_each_online_node(nid) {
1274 init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid);
1275
1276 init_list(kmalloc_caches[KMALLOC_NORMAL][INDEX_NODE],
1277 &init_kmem_cache_node[SIZE_NODE + nid], nid);
1278 }
1279 }
1280
1281 create_kmalloc_caches(ARCH_KMALLOC_FLAGS);
1282 }
1283
kmem_cache_init_late(void)1284 void __init kmem_cache_init_late(void)
1285 {
1286 struct kmem_cache *cachep;
1287
1288 /* 6) resize the head arrays to their final sizes */
1289 mutex_lock(&slab_mutex);
1290 list_for_each_entry(cachep, &slab_caches, list)
1291 if (enable_cpucache(cachep, GFP_NOWAIT))
1292 BUG();
1293 mutex_unlock(&slab_mutex);
1294
1295 /* Done! */
1296 slab_state = FULL;
1297
1298 #ifdef CONFIG_NUMA
1299 /*
1300 * Register a memory hotplug callback that initializes and frees
1301 * node.
1302 */
1303 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
1304 #endif
1305
1306 /*
1307 * The reap timers are started later, with a module init call: That part
1308 * of the kernel is not yet operational.
1309 */
1310 }
1311
cpucache_init(void)1312 static int __init cpucache_init(void)
1313 {
1314 int ret;
1315
1316 /*
1317 * Register the timers that return unneeded pages to the page allocator
1318 */
1319 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SLAB online",
1320 slab_online_cpu, slab_offline_cpu);
1321 WARN_ON(ret < 0);
1322
1323 return 0;
1324 }
1325 __initcall(cpucache_init);
1326
1327 static noinline void
slab_out_of_memory(struct kmem_cache * cachep,gfp_t gfpflags,int nodeid)1328 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
1329 {
1330 #if DEBUG
1331 struct kmem_cache_node *n;
1332 unsigned long flags;
1333 int node;
1334 static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
1335 DEFAULT_RATELIMIT_BURST);
1336
1337 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs))
1338 return;
1339
1340 pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
1341 nodeid, gfpflags, &gfpflags);
1342 pr_warn(" cache: %s, object size: %d, order: %d\n",
1343 cachep->name, cachep->size, cachep->gfporder);
1344
1345 for_each_kmem_cache_node(cachep, node, n) {
1346 unsigned long total_slabs, free_slabs, free_objs;
1347
1348 spin_lock_irqsave(&n->list_lock, flags);
1349 total_slabs = n->total_slabs;
1350 free_slabs = n->free_slabs;
1351 free_objs = n->free_objects;
1352 spin_unlock_irqrestore(&n->list_lock, flags);
1353
1354 pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld\n",
1355 node, total_slabs - free_slabs, total_slabs,
1356 (total_slabs * cachep->num) - free_objs,
1357 total_slabs * cachep->num);
1358 }
1359 #endif
1360 }
1361
1362 /*
1363 * Interface to system's page allocator. No need to hold the
1364 * kmem_cache_node ->list_lock.
1365 *
1366 * If we requested dmaable memory, we will get it. Even if we
1367 * did not request dmaable memory, we might get it, but that
1368 * would be relatively rare and ignorable.
1369 */
kmem_getpages(struct kmem_cache * cachep,gfp_t flags,int nodeid)1370 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags,
1371 int nodeid)
1372 {
1373 struct page *page;
1374
1375 flags |= cachep->allocflags;
1376
1377 page = __alloc_pages_node(nodeid, flags, cachep->gfporder);
1378 if (!page) {
1379 slab_out_of_memory(cachep, flags, nodeid);
1380 return NULL;
1381 }
1382
1383 account_slab_page(page, cachep->gfporder, cachep);
1384 __SetPageSlab(page);
1385 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
1386 if (sk_memalloc_socks() && page_is_pfmemalloc(page))
1387 SetPageSlabPfmemalloc(page);
1388
1389 return page;
1390 }
1391
1392 /*
1393 * Interface to system's page release.
1394 */
kmem_freepages(struct kmem_cache * cachep,struct page * page)1395 static void kmem_freepages(struct kmem_cache *cachep, struct page *page)
1396 {
1397 int order = cachep->gfporder;
1398
1399 BUG_ON(!PageSlab(page));
1400 __ClearPageSlabPfmemalloc(page);
1401 __ClearPageSlab(page);
1402 page_mapcount_reset(page);
1403 page->mapping = NULL;
1404
1405 if (current->reclaim_state)
1406 current->reclaim_state->reclaimed_slab += 1 << order;
1407 unaccount_slab_page(page, order, cachep);
1408 __free_pages(page, order);
1409 }
1410
kmem_rcu_free(struct rcu_head * head)1411 static void kmem_rcu_free(struct rcu_head *head)
1412 {
1413 struct kmem_cache *cachep;
1414 struct page *page;
1415
1416 page = container_of(head, struct page, rcu_head);
1417 cachep = page->slab_cache;
1418
1419 kmem_freepages(cachep, page);
1420 }
1421
1422 #if DEBUG
is_debug_pagealloc_cache(struct kmem_cache * cachep)1423 static bool is_debug_pagealloc_cache(struct kmem_cache *cachep)
1424 {
1425 if (debug_pagealloc_enabled_static() && OFF_SLAB(cachep) &&
1426 (cachep->size % PAGE_SIZE) == 0)
1427 return true;
1428
1429 return false;
1430 }
1431
1432 #ifdef CONFIG_DEBUG_PAGEALLOC
slab_kernel_map(struct kmem_cache * cachep,void * objp,int map)1433 static void slab_kernel_map(struct kmem_cache *cachep, void *objp, int map)
1434 {
1435 if (!is_debug_pagealloc_cache(cachep))
1436 return;
1437
1438 __kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map);
1439 }
1440
1441 #else
slab_kernel_map(struct kmem_cache * cachep,void * objp,int map)1442 static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp,
1443 int map) {}
1444
1445 #endif
1446
poison_obj(struct kmem_cache * cachep,void * addr,unsigned char val)1447 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val)
1448 {
1449 int size = cachep->object_size;
1450 addr = &((char *)addr)[obj_offset(cachep)];
1451
1452 memset(addr, val, size);
1453 *(unsigned char *)(addr + size - 1) = POISON_END;
1454 }
1455
dump_line(char * data,int offset,int limit)1456 static void dump_line(char *data, int offset, int limit)
1457 {
1458 int i;
1459 unsigned char error = 0;
1460 int bad_count = 0;
1461
1462 pr_err("%03x: ", offset);
1463 for (i = 0; i < limit; i++) {
1464 if (data[offset + i] != POISON_FREE) {
1465 error = data[offset + i];
1466 bad_count++;
1467 }
1468 }
1469 print_hex_dump(KERN_CONT, "", 0, 16, 1,
1470 &data[offset], limit, 1);
1471
1472 if (bad_count == 1) {
1473 error ^= POISON_FREE;
1474 if (!(error & (error - 1))) {
1475 pr_err("Single bit error detected. Probably bad RAM.\n");
1476 #ifdef CONFIG_X86
1477 pr_err("Run memtest86+ or a similar memory test tool.\n");
1478 #else
1479 pr_err("Run a memory test tool.\n");
1480 #endif
1481 }
1482 }
1483 }
1484 #endif
1485
1486 #if DEBUG
1487
print_objinfo(struct kmem_cache * cachep,void * objp,int lines)1488 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
1489 {
1490 int i, size;
1491 char *realobj;
1492
1493 if (cachep->flags & SLAB_RED_ZONE) {
1494 pr_err("Redzone: 0x%llx/0x%llx\n",
1495 *dbg_redzone1(cachep, objp),
1496 *dbg_redzone2(cachep, objp));
1497 }
1498
1499 if (cachep->flags & SLAB_STORE_USER)
1500 pr_err("Last user: (%pSR)\n", *dbg_userword(cachep, objp));
1501 realobj = (char *)objp + obj_offset(cachep);
1502 size = cachep->object_size;
1503 for (i = 0; i < size && lines; i += 16, lines--) {
1504 int limit;
1505 limit = 16;
1506 if (i + limit > size)
1507 limit = size - i;
1508 dump_line(realobj, i, limit);
1509 }
1510 }
1511
check_poison_obj(struct kmem_cache * cachep,void * objp)1512 static void check_poison_obj(struct kmem_cache *cachep, void *objp)
1513 {
1514 char *realobj;
1515 int size, i;
1516 int lines = 0;
1517
1518 if (is_debug_pagealloc_cache(cachep))
1519 return;
1520
1521 realobj = (char *)objp + obj_offset(cachep);
1522 size = cachep->object_size;
1523
1524 for (i = 0; i < size; i++) {
1525 char exp = POISON_FREE;
1526 if (i == size - 1)
1527 exp = POISON_END;
1528 if (realobj[i] != exp) {
1529 int limit;
1530 /* Mismatch ! */
1531 /* Print header */
1532 if (lines == 0) {
1533 pr_err("Slab corruption (%s): %s start=%px, len=%d\n",
1534 print_tainted(), cachep->name,
1535 realobj, size);
1536 print_objinfo(cachep, objp, 0);
1537 }
1538 /* Hexdump the affected line */
1539 i = (i / 16) * 16;
1540 limit = 16;
1541 if (i + limit > size)
1542 limit = size - i;
1543 dump_line(realobj, i, limit);
1544 i += 16;
1545 lines++;
1546 /* Limit to 5 lines */
1547 if (lines > 5)
1548 break;
1549 }
1550 }
1551 if (lines != 0) {
1552 /* Print some data about the neighboring objects, if they
1553 * exist:
1554 */
1555 struct page *page = virt_to_head_page(objp);
1556 unsigned int objnr;
1557
1558 objnr = obj_to_index(cachep, page, objp);
1559 if (objnr) {
1560 objp = index_to_obj(cachep, page, objnr - 1);
1561 realobj = (char *)objp + obj_offset(cachep);
1562 pr_err("Prev obj: start=%px, len=%d\n", realobj, size);
1563 print_objinfo(cachep, objp, 2);
1564 }
1565 if (objnr + 1 < cachep->num) {
1566 objp = index_to_obj(cachep, page, objnr + 1);
1567 realobj = (char *)objp + obj_offset(cachep);
1568 pr_err("Next obj: start=%px, len=%d\n", realobj, size);
1569 print_objinfo(cachep, objp, 2);
1570 }
1571 }
1572 }
1573 #endif
1574
1575 #if DEBUG
slab_destroy_debugcheck(struct kmem_cache * cachep,struct page * page)1576 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1577 struct page *page)
1578 {
1579 int i;
1580
1581 if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) {
1582 poison_obj(cachep, page->freelist - obj_offset(cachep),
1583 POISON_FREE);
1584 }
1585
1586 for (i = 0; i < cachep->num; i++) {
1587 void *objp = index_to_obj(cachep, page, i);
1588
1589 if (cachep->flags & SLAB_POISON) {
1590 check_poison_obj(cachep, objp);
1591 slab_kernel_map(cachep, objp, 1);
1592 }
1593 if (cachep->flags & SLAB_RED_ZONE) {
1594 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
1595 slab_error(cachep, "start of a freed object was overwritten");
1596 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
1597 slab_error(cachep, "end of a freed object was overwritten");
1598 }
1599 }
1600 }
1601 #else
slab_destroy_debugcheck(struct kmem_cache * cachep,struct page * page)1602 static void slab_destroy_debugcheck(struct kmem_cache *cachep,
1603 struct page *page)
1604 {
1605 }
1606 #endif
1607
1608 /**
1609 * slab_destroy - destroy and release all objects in a slab
1610 * @cachep: cache pointer being destroyed
1611 * @page: page pointer being destroyed
1612 *
1613 * Destroy all the objs in a slab page, and release the mem back to the system.
1614 * Before calling the slab page must have been unlinked from the cache. The
1615 * kmem_cache_node ->list_lock is not held/needed.
1616 */
slab_destroy(struct kmem_cache * cachep,struct page * page)1617 static void slab_destroy(struct kmem_cache *cachep, struct page *page)
1618 {
1619 void *freelist;
1620
1621 freelist = page->freelist;
1622 slab_destroy_debugcheck(cachep, page);
1623 if (unlikely(cachep->flags & SLAB_TYPESAFE_BY_RCU))
1624 call_rcu(&page->rcu_head, kmem_rcu_free);
1625 else
1626 kmem_freepages(cachep, page);
1627
1628 /*
1629 * From now on, we don't use freelist
1630 * although actual page can be freed in rcu context
1631 */
1632 if (OFF_SLAB(cachep))
1633 kmem_cache_free(cachep->freelist_cache, freelist);
1634 }
1635
1636 /*
1637 * Update the size of the caches before calling slabs_destroy as it may
1638 * recursively call kfree.
1639 */
slabs_destroy(struct kmem_cache * cachep,struct list_head * list)1640 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list)
1641 {
1642 struct page *page, *n;
1643
1644 list_for_each_entry_safe(page, n, list, slab_list) {
1645 list_del(&page->slab_list);
1646 slab_destroy(cachep, page);
1647 }
1648 }
1649
1650 /**
1651 * calculate_slab_order - calculate size (page order) of slabs
1652 * @cachep: pointer to the cache that is being created
1653 * @size: size of objects to be created in this cache.
1654 * @flags: slab allocation flags
1655 *
1656 * Also calculates the number of objects per slab.
1657 *
1658 * This could be made much more intelligent. For now, try to avoid using
1659 * high order pages for slabs. When the gfp() functions are more friendly
1660 * towards high-order requests, this should be changed.
1661 *
1662 * Return: number of left-over bytes in a slab
1663 */
calculate_slab_order(struct kmem_cache * cachep,size_t size,slab_flags_t flags)1664 static size_t calculate_slab_order(struct kmem_cache *cachep,
1665 size_t size, slab_flags_t flags)
1666 {
1667 size_t left_over = 0;
1668 int gfporder;
1669
1670 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
1671 unsigned int num;
1672 size_t remainder;
1673
1674 num = cache_estimate(gfporder, size, flags, &remainder);
1675 if (!num)
1676 continue;
1677
1678 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */
1679 if (num > SLAB_OBJ_MAX_NUM)
1680 break;
1681
1682 if (flags & CFLGS_OFF_SLAB) {
1683 struct kmem_cache *freelist_cache;
1684 size_t freelist_size;
1685
1686 freelist_size = num * sizeof(freelist_idx_t);
1687 freelist_cache = kmalloc_slab(freelist_size, 0u);
1688 if (!freelist_cache)
1689 continue;
1690
1691 /*
1692 * Needed to avoid possible looping condition
1693 * in cache_grow_begin()
1694 */
1695 if (OFF_SLAB(freelist_cache))
1696 continue;
1697
1698 /* check if off slab has enough benefit */
1699 if (freelist_cache->size > cachep->size / 2)
1700 continue;
1701 }
1702
1703 /* Found something acceptable - save it away */
1704 cachep->num = num;
1705 cachep->gfporder = gfporder;
1706 left_over = remainder;
1707
1708 /*
1709 * A VFS-reclaimable slab tends to have most allocations
1710 * as GFP_NOFS and we really don't want to have to be allocating
1711 * higher-order pages when we are unable to shrink dcache.
1712 */
1713 if (flags & SLAB_RECLAIM_ACCOUNT)
1714 break;
1715
1716 /*
1717 * Large number of objects is good, but very large slabs are
1718 * currently bad for the gfp()s.
1719 */
1720 if (gfporder >= slab_max_order)
1721 break;
1722
1723 /*
1724 * Acceptable internal fragmentation?
1725 */
1726 if (left_over * 8 <= (PAGE_SIZE << gfporder))
1727 break;
1728 }
1729 return left_over;
1730 }
1731
alloc_kmem_cache_cpus(struct kmem_cache * cachep,int entries,int batchcount)1732 static struct array_cache __percpu *alloc_kmem_cache_cpus(
1733 struct kmem_cache *cachep, int entries, int batchcount)
1734 {
1735 int cpu;
1736 size_t size;
1737 struct array_cache __percpu *cpu_cache;
1738
1739 size = sizeof(void *) * entries + sizeof(struct array_cache);
1740 cpu_cache = __alloc_percpu(size, sizeof(void *));
1741
1742 if (!cpu_cache)
1743 return NULL;
1744
1745 for_each_possible_cpu(cpu) {
1746 init_arraycache(per_cpu_ptr(cpu_cache, cpu),
1747 entries, batchcount);
1748 }
1749
1750 return cpu_cache;
1751 }
1752
setup_cpu_cache(struct kmem_cache * cachep,gfp_t gfp)1753 static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
1754 {
1755 if (slab_state >= FULL)
1756 return enable_cpucache(cachep, gfp);
1757
1758 cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1);
1759 if (!cachep->cpu_cache)
1760 return 1;
1761
1762 if (slab_state == DOWN) {
1763 /* Creation of first cache (kmem_cache). */
1764 set_up_node(kmem_cache, CACHE_CACHE);
1765 } else if (slab_state == PARTIAL) {
1766 /* For kmem_cache_node */
1767 set_up_node(cachep, SIZE_NODE);
1768 } else {
1769 int node;
1770
1771 for_each_online_node(node) {
1772 cachep->node[node] = kmalloc_node(
1773 sizeof(struct kmem_cache_node), gfp, node);
1774 BUG_ON(!cachep->node[node]);
1775 kmem_cache_node_init(cachep->node[node]);
1776 }
1777 }
1778
1779 cachep->node[numa_mem_id()]->next_reap =
1780 jiffies + REAPTIMEOUT_NODE +
1781 ((unsigned long)cachep) % REAPTIMEOUT_NODE;
1782
1783 cpu_cache_get(cachep)->avail = 0;
1784 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
1785 cpu_cache_get(cachep)->batchcount = 1;
1786 cpu_cache_get(cachep)->touched = 0;
1787 cachep->batchcount = 1;
1788 cachep->limit = BOOT_CPUCACHE_ENTRIES;
1789 return 0;
1790 }
1791
kmem_cache_flags(unsigned int object_size,slab_flags_t flags,const char * name)1792 slab_flags_t kmem_cache_flags(unsigned int object_size,
1793 slab_flags_t flags, const char *name)
1794 {
1795 return flags;
1796 }
1797
1798 struct kmem_cache *
__kmem_cache_alias(const char * name,unsigned int size,unsigned int align,slab_flags_t flags,void (* ctor)(void *))1799 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
1800 slab_flags_t flags, void (*ctor)(void *))
1801 {
1802 struct kmem_cache *cachep;
1803
1804 cachep = find_mergeable(size, align, flags, name, ctor);
1805 if (cachep) {
1806 cachep->refcount++;
1807
1808 /*
1809 * Adjust the object sizes so that we clear
1810 * the complete object on kzalloc.
1811 */
1812 cachep->object_size = max_t(int, cachep->object_size, size);
1813 }
1814 return cachep;
1815 }
1816
set_objfreelist_slab_cache(struct kmem_cache * cachep,size_t size,slab_flags_t flags)1817 static bool set_objfreelist_slab_cache(struct kmem_cache *cachep,
1818 size_t size, slab_flags_t flags)
1819 {
1820 size_t left;
1821
1822 cachep->num = 0;
1823
1824 /*
1825 * If slab auto-initialization on free is enabled, store the freelist
1826 * off-slab, so that its contents don't end up in one of the allocated
1827 * objects.
1828 */
1829 if (unlikely(slab_want_init_on_free(cachep)))
1830 return false;
1831
1832 if (cachep->ctor || flags & SLAB_TYPESAFE_BY_RCU)
1833 return false;
1834
1835 left = calculate_slab_order(cachep, size,
1836 flags | CFLGS_OBJFREELIST_SLAB);
1837 if (!cachep->num)
1838 return false;
1839
1840 if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size)
1841 return false;
1842
1843 cachep->colour = left / cachep->colour_off;
1844
1845 return true;
1846 }
1847
set_off_slab_cache(struct kmem_cache * cachep,size_t size,slab_flags_t flags)1848 static bool set_off_slab_cache(struct kmem_cache *cachep,
1849 size_t size, slab_flags_t flags)
1850 {
1851 size_t left;
1852
1853 cachep->num = 0;
1854
1855 /*
1856 * Always use on-slab management when SLAB_NOLEAKTRACE
1857 * to avoid recursive calls into kmemleak.
1858 */
1859 if (flags & SLAB_NOLEAKTRACE)
1860 return false;
1861
1862 /*
1863 * Size is large, assume best to place the slab management obj
1864 * off-slab (should allow better packing of objs).
1865 */
1866 left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB);
1867 if (!cachep->num)
1868 return false;
1869
1870 /*
1871 * If the slab has been placed off-slab, and we have enough space then
1872 * move it on-slab. This is at the expense of any extra colouring.
1873 */
1874 if (left >= cachep->num * sizeof(freelist_idx_t))
1875 return false;
1876
1877 cachep->colour = left / cachep->colour_off;
1878
1879 return true;
1880 }
1881
set_on_slab_cache(struct kmem_cache * cachep,size_t size,slab_flags_t flags)1882 static bool set_on_slab_cache(struct kmem_cache *cachep,
1883 size_t size, slab_flags_t flags)
1884 {
1885 size_t left;
1886
1887 cachep->num = 0;
1888
1889 left = calculate_slab_order(cachep, size, flags);
1890 if (!cachep->num)
1891 return false;
1892
1893 cachep->colour = left / cachep->colour_off;
1894
1895 return true;
1896 }
1897
1898 /**
1899 * __kmem_cache_create - Create a cache.
1900 * @cachep: cache management descriptor
1901 * @flags: SLAB flags
1902 *
1903 * Returns a ptr to the cache on success, NULL on failure.
1904 * Cannot be called within a int, but can be interrupted.
1905 * The @ctor is run when new pages are allocated by the cache.
1906 *
1907 * The flags are
1908 *
1909 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
1910 * to catch references to uninitialised memory.
1911 *
1912 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
1913 * for buffer overruns.
1914 *
1915 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
1916 * cacheline. This can be beneficial if you're counting cycles as closely
1917 * as davem.
1918 *
1919 * Return: a pointer to the created cache or %NULL in case of error
1920 */
__kmem_cache_create(struct kmem_cache * cachep,slab_flags_t flags)1921 int __kmem_cache_create(struct kmem_cache *cachep, slab_flags_t flags)
1922 {
1923 size_t ralign = BYTES_PER_WORD;
1924 gfp_t gfp;
1925 int err;
1926 unsigned int size = cachep->size;
1927
1928 #if DEBUG
1929 #if FORCED_DEBUG
1930 /*
1931 * Enable redzoning and last user accounting, except for caches with
1932 * large objects, if the increased size would increase the object size
1933 * above the next power of two: caches with object sizes just above a
1934 * power of two have a significant amount of internal fragmentation.
1935 */
1936 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN +
1937 2 * sizeof(unsigned long long)))
1938 flags |= SLAB_RED_ZONE | SLAB_STORE_USER;
1939 if (!(flags & SLAB_TYPESAFE_BY_RCU))
1940 flags |= SLAB_POISON;
1941 #endif
1942 #endif
1943
1944 /*
1945 * Check that size is in terms of words. This is needed to avoid
1946 * unaligned accesses for some archs when redzoning is used, and makes
1947 * sure any on-slab bufctl's are also correctly aligned.
1948 */
1949 size = ALIGN(size, BYTES_PER_WORD);
1950
1951 if (flags & SLAB_RED_ZONE) {
1952 ralign = REDZONE_ALIGN;
1953 /* If redzoning, ensure that the second redzone is suitably
1954 * aligned, by adjusting the object size accordingly. */
1955 size = ALIGN(size, REDZONE_ALIGN);
1956 }
1957
1958 /* 3) caller mandated alignment */
1959 if (ralign < cachep->align) {
1960 ralign = cachep->align;
1961 }
1962 /* disable debug if necessary */
1963 if (ralign > __alignof__(unsigned long long))
1964 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
1965 /*
1966 * 4) Store it.
1967 */
1968 cachep->align = ralign;
1969 cachep->colour_off = cache_line_size();
1970 /* Offset must be a multiple of the alignment. */
1971 if (cachep->colour_off < cachep->align)
1972 cachep->colour_off = cachep->align;
1973
1974 if (slab_is_available())
1975 gfp = GFP_KERNEL;
1976 else
1977 gfp = GFP_NOWAIT;
1978
1979 #if DEBUG
1980
1981 /*
1982 * Both debugging options require word-alignment which is calculated
1983 * into align above.
1984 */
1985 if (flags & SLAB_RED_ZONE) {
1986 /* add space for red zone words */
1987 cachep->obj_offset += sizeof(unsigned long long);
1988 size += 2 * sizeof(unsigned long long);
1989 }
1990 if (flags & SLAB_STORE_USER) {
1991 /* user store requires one word storage behind the end of
1992 * the real object. But if the second red zone needs to be
1993 * aligned to 64 bits, we must allow that much space.
1994 */
1995 if (flags & SLAB_RED_ZONE)
1996 size += REDZONE_ALIGN;
1997 else
1998 size += BYTES_PER_WORD;
1999 }
2000 #endif
2001
2002 kasan_cache_create(cachep, &size, &flags);
2003
2004 size = ALIGN(size, cachep->align);
2005 /*
2006 * We should restrict the number of objects in a slab to implement
2007 * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition.
2008 */
2009 if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE)
2010 size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align);
2011
2012 #if DEBUG
2013 /*
2014 * To activate debug pagealloc, off-slab management is necessary
2015 * requirement. In early phase of initialization, small sized slab
2016 * doesn't get initialized so it would not be possible. So, we need
2017 * to check size >= 256. It guarantees that all necessary small
2018 * sized slab is initialized in current slab initialization sequence.
2019 */
2020 if (debug_pagealloc_enabled_static() && (flags & SLAB_POISON) &&
2021 size >= 256 && cachep->object_size > cache_line_size()) {
2022 if (size < PAGE_SIZE || size % PAGE_SIZE == 0) {
2023 size_t tmp_size = ALIGN(size, PAGE_SIZE);
2024
2025 if (set_off_slab_cache(cachep, tmp_size, flags)) {
2026 flags |= CFLGS_OFF_SLAB;
2027 cachep->obj_offset += tmp_size - size;
2028 size = tmp_size;
2029 goto done;
2030 }
2031 }
2032 }
2033 #endif
2034
2035 if (set_objfreelist_slab_cache(cachep, size, flags)) {
2036 flags |= CFLGS_OBJFREELIST_SLAB;
2037 goto done;
2038 }
2039
2040 if (set_off_slab_cache(cachep, size, flags)) {
2041 flags |= CFLGS_OFF_SLAB;
2042 goto done;
2043 }
2044
2045 if (set_on_slab_cache(cachep, size, flags))
2046 goto done;
2047
2048 return -E2BIG;
2049
2050 done:
2051 cachep->freelist_size = cachep->num * sizeof(freelist_idx_t);
2052 cachep->flags = flags;
2053 cachep->allocflags = __GFP_COMP;
2054 if (flags & SLAB_CACHE_DMA)
2055 cachep->allocflags |= GFP_DMA;
2056 if (flags & SLAB_CACHE_DMA32)
2057 cachep->allocflags |= GFP_DMA32;
2058 if (flags & SLAB_RECLAIM_ACCOUNT)
2059 cachep->allocflags |= __GFP_RECLAIMABLE;
2060 cachep->size = size;
2061 cachep->reciprocal_buffer_size = reciprocal_value(size);
2062
2063 #if DEBUG
2064 /*
2065 * If we're going to use the generic kernel_map_pages()
2066 * poisoning, then it's going to smash the contents of
2067 * the redzone and userword anyhow, so switch them off.
2068 */
2069 if (IS_ENABLED(CONFIG_PAGE_POISONING) &&
2070 (cachep->flags & SLAB_POISON) &&
2071 is_debug_pagealloc_cache(cachep))
2072 cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
2073 #endif
2074
2075 if (OFF_SLAB(cachep)) {
2076 cachep->freelist_cache =
2077 kmalloc_slab(cachep->freelist_size, 0u);
2078 }
2079
2080 err = setup_cpu_cache(cachep, gfp);
2081 if (err) {
2082 __kmem_cache_release(cachep);
2083 return err;
2084 }
2085
2086 return 0;
2087 }
2088
2089 #if DEBUG
check_irq_off(void)2090 static void check_irq_off(void)
2091 {
2092 BUG_ON(!irqs_disabled());
2093 }
2094
check_irq_on(void)2095 static void check_irq_on(void)
2096 {
2097 BUG_ON(irqs_disabled());
2098 }
2099
check_mutex_acquired(void)2100 static void check_mutex_acquired(void)
2101 {
2102 BUG_ON(!mutex_is_locked(&slab_mutex));
2103 }
2104
check_spinlock_acquired(struct kmem_cache * cachep)2105 static void check_spinlock_acquired(struct kmem_cache *cachep)
2106 {
2107 #ifdef CONFIG_SMP
2108 check_irq_off();
2109 assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock);
2110 #endif
2111 }
2112
check_spinlock_acquired_node(struct kmem_cache * cachep,int node)2113 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
2114 {
2115 #ifdef CONFIG_SMP
2116 check_irq_off();
2117 assert_spin_locked(&get_node(cachep, node)->list_lock);
2118 #endif
2119 }
2120
2121 #else
2122 #define check_irq_off() do { } while(0)
2123 #define check_irq_on() do { } while(0)
2124 #define check_mutex_acquired() do { } while(0)
2125 #define check_spinlock_acquired(x) do { } while(0)
2126 #define check_spinlock_acquired_node(x, y) do { } while(0)
2127 #endif
2128
drain_array_locked(struct kmem_cache * cachep,struct array_cache * ac,int node,bool free_all,struct list_head * list)2129 static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac,
2130 int node, bool free_all, struct list_head *list)
2131 {
2132 int tofree;
2133
2134 if (!ac || !ac->avail)
2135 return;
2136
2137 tofree = free_all ? ac->avail : (ac->limit + 4) / 5;
2138 if (tofree > ac->avail)
2139 tofree = (ac->avail + 1) / 2;
2140
2141 free_block(cachep, ac->entry, tofree, node, list);
2142 ac->avail -= tofree;
2143 memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail);
2144 }
2145
do_drain(void * arg)2146 static void do_drain(void *arg)
2147 {
2148 struct kmem_cache *cachep = arg;
2149 struct array_cache *ac;
2150 int node = numa_mem_id();
2151 struct kmem_cache_node *n;
2152 LIST_HEAD(list);
2153
2154 check_irq_off();
2155 ac = cpu_cache_get(cachep);
2156 n = get_node(cachep, node);
2157 spin_lock(&n->list_lock);
2158 free_block(cachep, ac->entry, ac->avail, node, &list);
2159 spin_unlock(&n->list_lock);
2160 ac->avail = 0;
2161 slabs_destroy(cachep, &list);
2162 }
2163
drain_cpu_caches(struct kmem_cache * cachep)2164 static void drain_cpu_caches(struct kmem_cache *cachep)
2165 {
2166 struct kmem_cache_node *n;
2167 int node;
2168 LIST_HEAD(list);
2169
2170 on_each_cpu(do_drain, cachep, 1);
2171 check_irq_on();
2172 for_each_kmem_cache_node(cachep, node, n)
2173 if (n->alien)
2174 drain_alien_cache(cachep, n->alien);
2175
2176 for_each_kmem_cache_node(cachep, node, n) {
2177 spin_lock_irq(&n->list_lock);
2178 drain_array_locked(cachep, n->shared, node, true, &list);
2179 spin_unlock_irq(&n->list_lock);
2180
2181 slabs_destroy(cachep, &list);
2182 }
2183 }
2184
2185 /*
2186 * Remove slabs from the list of free slabs.
2187 * Specify the number of slabs to drain in tofree.
2188 *
2189 * Returns the actual number of slabs released.
2190 */
drain_freelist(struct kmem_cache * cache,struct kmem_cache_node * n,int tofree)2191 static int drain_freelist(struct kmem_cache *cache,
2192 struct kmem_cache_node *n, int tofree)
2193 {
2194 struct list_head *p;
2195 int nr_freed;
2196 struct page *page;
2197
2198 nr_freed = 0;
2199 while (nr_freed < tofree && !list_empty(&n->slabs_free)) {
2200
2201 spin_lock_irq(&n->list_lock);
2202 p = n->slabs_free.prev;
2203 if (p == &n->slabs_free) {
2204 spin_unlock_irq(&n->list_lock);
2205 goto out;
2206 }
2207
2208 page = list_entry(p, struct page, slab_list);
2209 list_del(&page->slab_list);
2210 n->free_slabs--;
2211 n->total_slabs--;
2212 /*
2213 * Safe to drop the lock. The slab is no longer linked
2214 * to the cache.
2215 */
2216 n->free_objects -= cache->num;
2217 spin_unlock_irq(&n->list_lock);
2218 slab_destroy(cache, page);
2219 nr_freed++;
2220 }
2221 out:
2222 return nr_freed;
2223 }
2224
__kmem_cache_empty(struct kmem_cache * s)2225 bool __kmem_cache_empty(struct kmem_cache *s)
2226 {
2227 int node;
2228 struct kmem_cache_node *n;
2229
2230 for_each_kmem_cache_node(s, node, n)
2231 if (!list_empty(&n->slabs_full) ||
2232 !list_empty(&n->slabs_partial))
2233 return false;
2234 return true;
2235 }
2236
__kmem_cache_shrink(struct kmem_cache * cachep)2237 int __kmem_cache_shrink(struct kmem_cache *cachep)
2238 {
2239 int ret = 0;
2240 int node;
2241 struct kmem_cache_node *n;
2242
2243 drain_cpu_caches(cachep);
2244
2245 check_irq_on();
2246 for_each_kmem_cache_node(cachep, node, n) {
2247 drain_freelist(cachep, n, INT_MAX);
2248
2249 ret += !list_empty(&n->slabs_full) ||
2250 !list_empty(&n->slabs_partial);
2251 }
2252 return (ret ? 1 : 0);
2253 }
2254
__kmem_cache_shutdown(struct kmem_cache * cachep)2255 int __kmem_cache_shutdown(struct kmem_cache *cachep)
2256 {
2257 return __kmem_cache_shrink(cachep);
2258 }
2259
__kmem_cache_release(struct kmem_cache * cachep)2260 void __kmem_cache_release(struct kmem_cache *cachep)
2261 {
2262 int i;
2263 struct kmem_cache_node *n;
2264
2265 cache_random_seq_destroy(cachep);
2266
2267 free_percpu(cachep->cpu_cache);
2268
2269 /* NUMA: free the node structures */
2270 for_each_kmem_cache_node(cachep, i, n) {
2271 kfree(n->shared);
2272 free_alien_cache(n->alien);
2273 kfree(n);
2274 cachep->node[i] = NULL;
2275 }
2276 }
2277
2278 /*
2279 * Get the memory for a slab management obj.
2280 *
2281 * For a slab cache when the slab descriptor is off-slab, the
2282 * slab descriptor can't come from the same cache which is being created,
2283 * Because if it is the case, that means we defer the creation of
2284 * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point.
2285 * And we eventually call down to __kmem_cache_create(), which
2286 * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one.
2287 * This is a "chicken-and-egg" problem.
2288 *
2289 * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches,
2290 * which are all initialized during kmem_cache_init().
2291 */
alloc_slabmgmt(struct kmem_cache * cachep,struct page * page,int colour_off,gfp_t local_flags,int nodeid)2292 static void *alloc_slabmgmt(struct kmem_cache *cachep,
2293 struct page *page, int colour_off,
2294 gfp_t local_flags, int nodeid)
2295 {
2296 void *freelist;
2297 void *addr = page_address(page);
2298
2299 page->s_mem = addr + colour_off;
2300 page->active = 0;
2301
2302 if (OBJFREELIST_SLAB(cachep))
2303 freelist = NULL;
2304 else if (OFF_SLAB(cachep)) {
2305 /* Slab management obj is off-slab. */
2306 freelist = kmem_cache_alloc_node(cachep->freelist_cache,
2307 local_flags, nodeid);
2308 } else {
2309 /* We will use last bytes at the slab for freelist */
2310 freelist = addr + (PAGE_SIZE << cachep->gfporder) -
2311 cachep->freelist_size;
2312 }
2313
2314 return freelist;
2315 }
2316
get_free_obj(struct page * page,unsigned int idx)2317 static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx)
2318 {
2319 return ((freelist_idx_t *)page->freelist)[idx];
2320 }
2321
set_free_obj(struct page * page,unsigned int idx,freelist_idx_t val)2322 static inline void set_free_obj(struct page *page,
2323 unsigned int idx, freelist_idx_t val)
2324 {
2325 ((freelist_idx_t *)(page->freelist))[idx] = val;
2326 }
2327
cache_init_objs_debug(struct kmem_cache * cachep,struct page * page)2328 static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page)
2329 {
2330 #if DEBUG
2331 int i;
2332
2333 for (i = 0; i < cachep->num; i++) {
2334 void *objp = index_to_obj(cachep, page, i);
2335
2336 if (cachep->flags & SLAB_STORE_USER)
2337 *dbg_userword(cachep, objp) = NULL;
2338
2339 if (cachep->flags & SLAB_RED_ZONE) {
2340 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2341 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2342 }
2343 /*
2344 * Constructors are not allowed to allocate memory from the same
2345 * cache which they are a constructor for. Otherwise, deadlock.
2346 * They must also be threaded.
2347 */
2348 if (cachep->ctor && !(cachep->flags & SLAB_POISON)) {
2349 kasan_unpoison_object_data(cachep,
2350 objp + obj_offset(cachep));
2351 cachep->ctor(objp + obj_offset(cachep));
2352 kasan_poison_object_data(
2353 cachep, objp + obj_offset(cachep));
2354 }
2355
2356 if (cachep->flags & SLAB_RED_ZONE) {
2357 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE)
2358 slab_error(cachep, "constructor overwrote the end of an object");
2359 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE)
2360 slab_error(cachep, "constructor overwrote the start of an object");
2361 }
2362 /* need to poison the objs? */
2363 if (cachep->flags & SLAB_POISON) {
2364 poison_obj(cachep, objp, POISON_FREE);
2365 slab_kernel_map(cachep, objp, 0);
2366 }
2367 }
2368 #endif
2369 }
2370
2371 #ifdef CONFIG_SLAB_FREELIST_RANDOM
2372 /* Hold information during a freelist initialization */
2373 union freelist_init_state {
2374 struct {
2375 unsigned int pos;
2376 unsigned int *list;
2377 unsigned int count;
2378 };
2379 struct rnd_state rnd_state;
2380 };
2381
2382 /*
2383 * Initialize the state based on the randomization methode available.
2384 * return true if the pre-computed list is available, false otherwize.
2385 */
freelist_state_initialize(union freelist_init_state * state,struct kmem_cache * cachep,unsigned int count)2386 static bool freelist_state_initialize(union freelist_init_state *state,
2387 struct kmem_cache *cachep,
2388 unsigned int count)
2389 {
2390 bool ret;
2391 unsigned int rand;
2392
2393 /* Use best entropy available to define a random shift */
2394 rand = get_random_int();
2395
2396 /* Use a random state if the pre-computed list is not available */
2397 if (!cachep->random_seq) {
2398 prandom_seed_state(&state->rnd_state, rand);
2399 ret = false;
2400 } else {
2401 state->list = cachep->random_seq;
2402 state->count = count;
2403 state->pos = rand % count;
2404 ret = true;
2405 }
2406 return ret;
2407 }
2408
2409 /* Get the next entry on the list and randomize it using a random shift */
next_random_slot(union freelist_init_state * state)2410 static freelist_idx_t next_random_slot(union freelist_init_state *state)
2411 {
2412 if (state->pos >= state->count)
2413 state->pos = 0;
2414 return state->list[state->pos++];
2415 }
2416
2417 /* Swap two freelist entries */
swap_free_obj(struct page * page,unsigned int a,unsigned int b)2418 static void swap_free_obj(struct page *page, unsigned int a, unsigned int b)
2419 {
2420 swap(((freelist_idx_t *)page->freelist)[a],
2421 ((freelist_idx_t *)page->freelist)[b]);
2422 }
2423
2424 /*
2425 * Shuffle the freelist initialization state based on pre-computed lists.
2426 * return true if the list was successfully shuffled, false otherwise.
2427 */
shuffle_freelist(struct kmem_cache * cachep,struct page * page)2428 static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page)
2429 {
2430 unsigned int objfreelist = 0, i, rand, count = cachep->num;
2431 union freelist_init_state state;
2432 bool precomputed;
2433
2434 if (count < 2)
2435 return false;
2436
2437 precomputed = freelist_state_initialize(&state, cachep, count);
2438
2439 /* Take a random entry as the objfreelist */
2440 if (OBJFREELIST_SLAB(cachep)) {
2441 if (!precomputed)
2442 objfreelist = count - 1;
2443 else
2444 objfreelist = next_random_slot(&state);
2445 page->freelist = index_to_obj(cachep, page, objfreelist) +
2446 obj_offset(cachep);
2447 count--;
2448 }
2449
2450 /*
2451 * On early boot, generate the list dynamically.
2452 * Later use a pre-computed list for speed.
2453 */
2454 if (!precomputed) {
2455 for (i = 0; i < count; i++)
2456 set_free_obj(page, i, i);
2457
2458 /* Fisher-Yates shuffle */
2459 for (i = count - 1; i > 0; i--) {
2460 rand = prandom_u32_state(&state.rnd_state);
2461 rand %= (i + 1);
2462 swap_free_obj(page, i, rand);
2463 }
2464 } else {
2465 for (i = 0; i < count; i++)
2466 set_free_obj(page, i, next_random_slot(&state));
2467 }
2468
2469 if (OBJFREELIST_SLAB(cachep))
2470 set_free_obj(page, cachep->num - 1, objfreelist);
2471
2472 return true;
2473 }
2474 #else
shuffle_freelist(struct kmem_cache * cachep,struct page * page)2475 static inline bool shuffle_freelist(struct kmem_cache *cachep,
2476 struct page *page)
2477 {
2478 return false;
2479 }
2480 #endif /* CONFIG_SLAB_FREELIST_RANDOM */
2481
cache_init_objs(struct kmem_cache * cachep,struct page * page)2482 static void cache_init_objs(struct kmem_cache *cachep,
2483 struct page *page)
2484 {
2485 int i;
2486 void *objp;
2487 bool shuffled;
2488
2489 cache_init_objs_debug(cachep, page);
2490
2491 /* Try to randomize the freelist if enabled */
2492 shuffled = shuffle_freelist(cachep, page);
2493
2494 if (!shuffled && OBJFREELIST_SLAB(cachep)) {
2495 page->freelist = index_to_obj(cachep, page, cachep->num - 1) +
2496 obj_offset(cachep);
2497 }
2498
2499 for (i = 0; i < cachep->num; i++) {
2500 objp = index_to_obj(cachep, page, i);
2501 objp = kasan_init_slab_obj(cachep, objp);
2502
2503 /* constructor could break poison info */
2504 if (DEBUG == 0 && cachep->ctor) {
2505 kasan_unpoison_object_data(cachep, objp);
2506 cachep->ctor(objp);
2507 kasan_poison_object_data(cachep, objp);
2508 }
2509
2510 if (!shuffled)
2511 set_free_obj(page, i, i);
2512 }
2513 }
2514
slab_get_obj(struct kmem_cache * cachep,struct page * page)2515 static void *slab_get_obj(struct kmem_cache *cachep, struct page *page)
2516 {
2517 void *objp;
2518
2519 objp = index_to_obj(cachep, page, get_free_obj(page, page->active));
2520 page->active++;
2521
2522 return objp;
2523 }
2524
slab_put_obj(struct kmem_cache * cachep,struct page * page,void * objp)2525 static void slab_put_obj(struct kmem_cache *cachep,
2526 struct page *page, void *objp)
2527 {
2528 unsigned int objnr = obj_to_index(cachep, page, objp);
2529 #if DEBUG
2530 unsigned int i;
2531
2532 /* Verify double free bug */
2533 for (i = page->active; i < cachep->num; i++) {
2534 if (get_free_obj(page, i) == objnr) {
2535 pr_err("slab: double free detected in cache '%s', objp %px\n",
2536 cachep->name, objp);
2537 BUG();
2538 }
2539 }
2540 #endif
2541 page->active--;
2542 if (!page->freelist)
2543 page->freelist = objp + obj_offset(cachep);
2544
2545 set_free_obj(page, page->active, objnr);
2546 }
2547
2548 /*
2549 * Map pages beginning at addr to the given cache and slab. This is required
2550 * for the slab allocator to be able to lookup the cache and slab of a
2551 * virtual address for kfree, ksize, and slab debugging.
2552 */
slab_map_pages(struct kmem_cache * cache,struct page * page,void * freelist)2553 static void slab_map_pages(struct kmem_cache *cache, struct page *page,
2554 void *freelist)
2555 {
2556 page->slab_cache = cache;
2557 page->freelist = freelist;
2558 }
2559
2560 /*
2561 * Grow (by 1) the number of slabs within a cache. This is called by
2562 * kmem_cache_alloc() when there are no active objs left in a cache.
2563 */
cache_grow_begin(struct kmem_cache * cachep,gfp_t flags,int nodeid)2564 static struct page *cache_grow_begin(struct kmem_cache *cachep,
2565 gfp_t flags, int nodeid)
2566 {
2567 void *freelist;
2568 size_t offset;
2569 gfp_t local_flags;
2570 int page_node;
2571 struct kmem_cache_node *n;
2572 struct page *page;
2573
2574 /*
2575 * Be lazy and only check for valid flags here, keeping it out of the
2576 * critical path in kmem_cache_alloc().
2577 */
2578 if (unlikely(flags & GFP_SLAB_BUG_MASK))
2579 flags = kmalloc_fix_flags(flags);
2580
2581 WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
2582 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
2583
2584 check_irq_off();
2585 if (gfpflags_allow_blocking(local_flags))
2586 local_irq_enable();
2587
2588 /*
2589 * Get mem for the objs. Attempt to allocate a physical page from
2590 * 'nodeid'.
2591 */
2592 page = kmem_getpages(cachep, local_flags, nodeid);
2593 if (!page)
2594 goto failed;
2595
2596 page_node = page_to_nid(page);
2597 n = get_node(cachep, page_node);
2598
2599 /* Get colour for the slab, and cal the next value. */
2600 n->colour_next++;
2601 if (n->colour_next >= cachep->colour)
2602 n->colour_next = 0;
2603
2604 offset = n->colour_next;
2605 if (offset >= cachep->colour)
2606 offset = 0;
2607
2608 offset *= cachep->colour_off;
2609
2610 /*
2611 * Call kasan_poison_slab() before calling alloc_slabmgmt(), so
2612 * page_address() in the latter returns a non-tagged pointer,
2613 * as it should be for slab pages.
2614 */
2615 kasan_poison_slab(page);
2616
2617 /* Get slab management. */
2618 freelist = alloc_slabmgmt(cachep, page, offset,
2619 local_flags & ~GFP_CONSTRAINT_MASK, page_node);
2620 if (OFF_SLAB(cachep) && !freelist)
2621 goto opps1;
2622
2623 slab_map_pages(cachep, page, freelist);
2624
2625 cache_init_objs(cachep, page);
2626
2627 if (gfpflags_allow_blocking(local_flags))
2628 local_irq_disable();
2629
2630 return page;
2631
2632 opps1:
2633 kmem_freepages(cachep, page);
2634 failed:
2635 if (gfpflags_allow_blocking(local_flags))
2636 local_irq_disable();
2637 return NULL;
2638 }
2639
cache_grow_end(struct kmem_cache * cachep,struct page * page)2640 static void cache_grow_end(struct kmem_cache *cachep, struct page *page)
2641 {
2642 struct kmem_cache_node *n;
2643 void *list = NULL;
2644
2645 check_irq_off();
2646
2647 if (!page)
2648 return;
2649
2650 INIT_LIST_HEAD(&page->slab_list);
2651 n = get_node(cachep, page_to_nid(page));
2652
2653 spin_lock(&n->list_lock);
2654 n->total_slabs++;
2655 if (!page->active) {
2656 list_add_tail(&page->slab_list, &n->slabs_free);
2657 n->free_slabs++;
2658 } else
2659 fixup_slab_list(cachep, n, page, &list);
2660
2661 STATS_INC_GROWN(cachep);
2662 n->free_objects += cachep->num - page->active;
2663 spin_unlock(&n->list_lock);
2664
2665 fixup_objfreelist_debug(cachep, &list);
2666 }
2667
2668 #if DEBUG
2669
2670 /*
2671 * Perform extra freeing checks:
2672 * - detect bad pointers.
2673 * - POISON/RED_ZONE checking
2674 */
kfree_debugcheck(const void * objp)2675 static void kfree_debugcheck(const void *objp)
2676 {
2677 if (!virt_addr_valid(objp)) {
2678 pr_err("kfree_debugcheck: out of range ptr %lxh\n",
2679 (unsigned long)objp);
2680 BUG();
2681 }
2682 }
2683
verify_redzone_free(struct kmem_cache * cache,void * obj)2684 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
2685 {
2686 unsigned long long redzone1, redzone2;
2687
2688 redzone1 = *dbg_redzone1(cache, obj);
2689 redzone2 = *dbg_redzone2(cache, obj);
2690
2691 /*
2692 * Redzone is ok.
2693 */
2694 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
2695 return;
2696
2697 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
2698 slab_error(cache, "double free detected");
2699 else
2700 slab_error(cache, "memory outside object was overwritten");
2701
2702 pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
2703 obj, redzone1, redzone2);
2704 }
2705
cache_free_debugcheck(struct kmem_cache * cachep,void * objp,unsigned long caller)2706 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
2707 unsigned long caller)
2708 {
2709 unsigned int objnr;
2710 struct page *page;
2711
2712 BUG_ON(virt_to_cache(objp) != cachep);
2713
2714 objp -= obj_offset(cachep);
2715 kfree_debugcheck(objp);
2716 page = virt_to_head_page(objp);
2717
2718 if (cachep->flags & SLAB_RED_ZONE) {
2719 verify_redzone_free(cachep, objp);
2720 *dbg_redzone1(cachep, objp) = RED_INACTIVE;
2721 *dbg_redzone2(cachep, objp) = RED_INACTIVE;
2722 }
2723 if (cachep->flags & SLAB_STORE_USER)
2724 *dbg_userword(cachep, objp) = (void *)caller;
2725
2726 objnr = obj_to_index(cachep, page, objp);
2727
2728 BUG_ON(objnr >= cachep->num);
2729 BUG_ON(objp != index_to_obj(cachep, page, objnr));
2730
2731 if (cachep->flags & SLAB_POISON) {
2732 poison_obj(cachep, objp, POISON_FREE);
2733 slab_kernel_map(cachep, objp, 0);
2734 }
2735 return objp;
2736 }
2737
2738 #else
2739 #define kfree_debugcheck(x) do { } while(0)
2740 #define cache_free_debugcheck(x,objp,z) (objp)
2741 #endif
2742
fixup_objfreelist_debug(struct kmem_cache * cachep,void ** list)2743 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep,
2744 void **list)
2745 {
2746 #if DEBUG
2747 void *next = *list;
2748 void *objp;
2749
2750 while (next) {
2751 objp = next - obj_offset(cachep);
2752 next = *(void **)next;
2753 poison_obj(cachep, objp, POISON_FREE);
2754 }
2755 #endif
2756 }
2757
fixup_slab_list(struct kmem_cache * cachep,struct kmem_cache_node * n,struct page * page,void ** list)2758 static inline void fixup_slab_list(struct kmem_cache *cachep,
2759 struct kmem_cache_node *n, struct page *page,
2760 void **list)
2761 {
2762 /* move slabp to correct slabp list: */
2763 list_del(&page->slab_list);
2764 if (page->active == cachep->num) {
2765 list_add(&page->slab_list, &n->slabs_full);
2766 if (OBJFREELIST_SLAB(cachep)) {
2767 #if DEBUG
2768 /* Poisoning will be done without holding the lock */
2769 if (cachep->flags & SLAB_POISON) {
2770 void **objp = page->freelist;
2771
2772 *objp = *list;
2773 *list = objp;
2774 }
2775 #endif
2776 page->freelist = NULL;
2777 }
2778 } else
2779 list_add(&page->slab_list, &n->slabs_partial);
2780 }
2781
2782 /* Try to find non-pfmemalloc slab if needed */
get_valid_first_slab(struct kmem_cache_node * n,struct page * page,bool pfmemalloc)2783 static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n,
2784 struct page *page, bool pfmemalloc)
2785 {
2786 if (!page)
2787 return NULL;
2788
2789 if (pfmemalloc)
2790 return page;
2791
2792 if (!PageSlabPfmemalloc(page))
2793 return page;
2794
2795 /* No need to keep pfmemalloc slab if we have enough free objects */
2796 if (n->free_objects > n->free_limit) {
2797 ClearPageSlabPfmemalloc(page);
2798 return page;
2799 }
2800
2801 /* Move pfmemalloc slab to the end of list to speed up next search */
2802 list_del(&page->slab_list);
2803 if (!page->active) {
2804 list_add_tail(&page->slab_list, &n->slabs_free);
2805 n->free_slabs++;
2806 } else
2807 list_add_tail(&page->slab_list, &n->slabs_partial);
2808
2809 list_for_each_entry(page, &n->slabs_partial, slab_list) {
2810 if (!PageSlabPfmemalloc(page))
2811 return page;
2812 }
2813
2814 n->free_touched = 1;
2815 list_for_each_entry(page, &n->slabs_free, slab_list) {
2816 if (!PageSlabPfmemalloc(page)) {
2817 n->free_slabs--;
2818 return page;
2819 }
2820 }
2821
2822 return NULL;
2823 }
2824
get_first_slab(struct kmem_cache_node * n,bool pfmemalloc)2825 static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc)
2826 {
2827 struct page *page;
2828
2829 assert_spin_locked(&n->list_lock);
2830 page = list_first_entry_or_null(&n->slabs_partial, struct page,
2831 slab_list);
2832 if (!page) {
2833 n->free_touched = 1;
2834 page = list_first_entry_or_null(&n->slabs_free, struct page,
2835 slab_list);
2836 if (page)
2837 n->free_slabs--;
2838 }
2839
2840 if (sk_memalloc_socks())
2841 page = get_valid_first_slab(n, page, pfmemalloc);
2842
2843 return page;
2844 }
2845
cache_alloc_pfmemalloc(struct kmem_cache * cachep,struct kmem_cache_node * n,gfp_t flags)2846 static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep,
2847 struct kmem_cache_node *n, gfp_t flags)
2848 {
2849 struct page *page;
2850 void *obj;
2851 void *list = NULL;
2852
2853 if (!gfp_pfmemalloc_allowed(flags))
2854 return NULL;
2855
2856 spin_lock(&n->list_lock);
2857 page = get_first_slab(n, true);
2858 if (!page) {
2859 spin_unlock(&n->list_lock);
2860 return NULL;
2861 }
2862
2863 obj = slab_get_obj(cachep, page);
2864 n->free_objects--;
2865
2866 fixup_slab_list(cachep, n, page, &list);
2867
2868 spin_unlock(&n->list_lock);
2869 fixup_objfreelist_debug(cachep, &list);
2870
2871 return obj;
2872 }
2873
2874 /*
2875 * Slab list should be fixed up by fixup_slab_list() for existing slab
2876 * or cache_grow_end() for new slab
2877 */
alloc_block(struct kmem_cache * cachep,struct array_cache * ac,struct page * page,int batchcount)2878 static __always_inline int alloc_block(struct kmem_cache *cachep,
2879 struct array_cache *ac, struct page *page, int batchcount)
2880 {
2881 /*
2882 * There must be at least one object available for
2883 * allocation.
2884 */
2885 BUG_ON(page->active >= cachep->num);
2886
2887 while (page->active < cachep->num && batchcount--) {
2888 STATS_INC_ALLOCED(cachep);
2889 STATS_INC_ACTIVE(cachep);
2890 STATS_SET_HIGH(cachep);
2891
2892 ac->entry[ac->avail++] = slab_get_obj(cachep, page);
2893 }
2894
2895 return batchcount;
2896 }
2897
cache_alloc_refill(struct kmem_cache * cachep,gfp_t flags)2898 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags)
2899 {
2900 int batchcount;
2901 struct kmem_cache_node *n;
2902 struct array_cache *ac, *shared;
2903 int node;
2904 void *list = NULL;
2905 struct page *page;
2906
2907 check_irq_off();
2908 node = numa_mem_id();
2909
2910 ac = cpu_cache_get(cachep);
2911 batchcount = ac->batchcount;
2912 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) {
2913 /*
2914 * If there was little recent activity on this cache, then
2915 * perform only a partial refill. Otherwise we could generate
2916 * refill bouncing.
2917 */
2918 batchcount = BATCHREFILL_LIMIT;
2919 }
2920 n = get_node(cachep, node);
2921
2922 BUG_ON(ac->avail > 0 || !n);
2923 shared = READ_ONCE(n->shared);
2924 if (!n->free_objects && (!shared || !shared->avail))
2925 goto direct_grow;
2926
2927 spin_lock(&n->list_lock);
2928 shared = READ_ONCE(n->shared);
2929
2930 /* See if we can refill from the shared array */
2931 if (shared && transfer_objects(ac, shared, batchcount)) {
2932 shared->touched = 1;
2933 goto alloc_done;
2934 }
2935
2936 while (batchcount > 0) {
2937 /* Get slab alloc is to come from. */
2938 page = get_first_slab(n, false);
2939 if (!page)
2940 goto must_grow;
2941
2942 check_spinlock_acquired(cachep);
2943
2944 batchcount = alloc_block(cachep, ac, page, batchcount);
2945 fixup_slab_list(cachep, n, page, &list);
2946 }
2947
2948 must_grow:
2949 n->free_objects -= ac->avail;
2950 alloc_done:
2951 spin_unlock(&n->list_lock);
2952 fixup_objfreelist_debug(cachep, &list);
2953
2954 direct_grow:
2955 if (unlikely(!ac->avail)) {
2956 /* Check if we can use obj in pfmemalloc slab */
2957 if (sk_memalloc_socks()) {
2958 void *obj = cache_alloc_pfmemalloc(cachep, n, flags);
2959
2960 if (obj)
2961 return obj;
2962 }
2963
2964 page = cache_grow_begin(cachep, gfp_exact_node(flags), node);
2965
2966 /*
2967 * cache_grow_begin() can reenable interrupts,
2968 * then ac could change.
2969 */
2970 ac = cpu_cache_get(cachep);
2971 if (!ac->avail && page)
2972 alloc_block(cachep, ac, page, batchcount);
2973 cache_grow_end(cachep, page);
2974
2975 if (!ac->avail)
2976 return NULL;
2977 }
2978 ac->touched = 1;
2979
2980 return ac->entry[--ac->avail];
2981 }
2982
cache_alloc_debugcheck_before(struct kmem_cache * cachep,gfp_t flags)2983 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
2984 gfp_t flags)
2985 {
2986 might_sleep_if(gfpflags_allow_blocking(flags));
2987 }
2988
2989 #if DEBUG
cache_alloc_debugcheck_after(struct kmem_cache * cachep,gfp_t flags,void * objp,unsigned long caller)2990 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
2991 gfp_t flags, void *objp, unsigned long caller)
2992 {
2993 WARN_ON_ONCE(cachep->ctor && (flags & __GFP_ZERO));
2994 if (!objp)
2995 return objp;
2996 if (cachep->flags & SLAB_POISON) {
2997 check_poison_obj(cachep, objp);
2998 slab_kernel_map(cachep, objp, 1);
2999 poison_obj(cachep, objp, POISON_INUSE);
3000 }
3001 if (cachep->flags & SLAB_STORE_USER)
3002 *dbg_userword(cachep, objp) = (void *)caller;
3003
3004 if (cachep->flags & SLAB_RED_ZONE) {
3005 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE ||
3006 *dbg_redzone2(cachep, objp) != RED_INACTIVE) {
3007 slab_error(cachep, "double free, or memory outside object was overwritten");
3008 pr_err("%px: redzone 1:0x%llx, redzone 2:0x%llx\n",
3009 objp, *dbg_redzone1(cachep, objp),
3010 *dbg_redzone2(cachep, objp));
3011 }
3012 *dbg_redzone1(cachep, objp) = RED_ACTIVE;
3013 *dbg_redzone2(cachep, objp) = RED_ACTIVE;
3014 }
3015
3016 objp += obj_offset(cachep);
3017 if (cachep->ctor && cachep->flags & SLAB_POISON)
3018 cachep->ctor(objp);
3019 if ((unsigned long)objp & (arch_slab_minalign() - 1)) {
3020 pr_err("0x%px: not aligned to arch_slab_minalign()=%u\n", objp,
3021 arch_slab_minalign());
3022 }
3023 return objp;
3024 }
3025 #else
3026 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
3027 #endif
3028
____cache_alloc(struct kmem_cache * cachep,gfp_t flags)3029 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3030 {
3031 void *objp;
3032 struct array_cache *ac;
3033
3034 check_irq_off();
3035
3036 ac = cpu_cache_get(cachep);
3037 if (likely(ac->avail)) {
3038 ac->touched = 1;
3039 objp = ac->entry[--ac->avail];
3040
3041 STATS_INC_ALLOCHIT(cachep);
3042 goto out;
3043 }
3044
3045 STATS_INC_ALLOCMISS(cachep);
3046 objp = cache_alloc_refill(cachep, flags);
3047 /*
3048 * the 'ac' may be updated by cache_alloc_refill(),
3049 * and kmemleak_erase() requires its correct value.
3050 */
3051 ac = cpu_cache_get(cachep);
3052
3053 out:
3054 /*
3055 * To avoid a false negative, if an object that is in one of the
3056 * per-CPU caches is leaked, we need to make sure kmemleak doesn't
3057 * treat the array pointers as a reference to the object.
3058 */
3059 if (objp)
3060 kmemleak_erase(&ac->entry[ac->avail]);
3061 return objp;
3062 }
3063
3064 #ifdef CONFIG_NUMA
3065 /*
3066 * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set.
3067 *
3068 * If we are in_interrupt, then process context, including cpusets and
3069 * mempolicy, may not apply and should not be used for allocation policy.
3070 */
alternate_node_alloc(struct kmem_cache * cachep,gfp_t flags)3071 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
3072 {
3073 int nid_alloc, nid_here;
3074
3075 if (in_interrupt() || (flags & __GFP_THISNODE))
3076 return NULL;
3077 nid_alloc = nid_here = numa_mem_id();
3078 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
3079 nid_alloc = cpuset_slab_spread_node();
3080 else if (current->mempolicy)
3081 nid_alloc = mempolicy_slab_node();
3082 if (nid_alloc != nid_here)
3083 return ____cache_alloc_node(cachep, flags, nid_alloc);
3084 return NULL;
3085 }
3086
3087 /*
3088 * Fallback function if there was no memory available and no objects on a
3089 * certain node and fall back is permitted. First we scan all the
3090 * available node for available objects. If that fails then we
3091 * perform an allocation without specifying a node. This allows the page
3092 * allocator to do its reclaim / fallback magic. We then insert the
3093 * slab into the proper nodelist and then allocate from it.
3094 */
fallback_alloc(struct kmem_cache * cache,gfp_t flags)3095 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
3096 {
3097 struct zonelist *zonelist;
3098 struct zoneref *z;
3099 struct zone *zone;
3100 enum zone_type highest_zoneidx = gfp_zone(flags);
3101 void *obj = NULL;
3102 struct page *page;
3103 int nid;
3104 unsigned int cpuset_mems_cookie;
3105
3106 if (flags & __GFP_THISNODE)
3107 return NULL;
3108
3109 retry_cpuset:
3110 cpuset_mems_cookie = read_mems_allowed_begin();
3111 zonelist = node_zonelist(mempolicy_slab_node(), flags);
3112
3113 retry:
3114 /*
3115 * Look through allowed nodes for objects available
3116 * from existing per node queues.
3117 */
3118 for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
3119 nid = zone_to_nid(zone);
3120
3121 if (cpuset_zone_allowed(zone, flags) &&
3122 get_node(cache, nid) &&
3123 get_node(cache, nid)->free_objects) {
3124 obj = ____cache_alloc_node(cache,
3125 gfp_exact_node(flags), nid);
3126 if (obj)
3127 break;
3128 }
3129 }
3130
3131 if (!obj) {
3132 /*
3133 * This allocation will be performed within the constraints
3134 * of the current cpuset / memory policy requirements.
3135 * We may trigger various forms of reclaim on the allowed
3136 * set and go into memory reserves if necessary.
3137 */
3138 page = cache_grow_begin(cache, flags, numa_mem_id());
3139 cache_grow_end(cache, page);
3140 if (page) {
3141 nid = page_to_nid(page);
3142 obj = ____cache_alloc_node(cache,
3143 gfp_exact_node(flags), nid);
3144
3145 /*
3146 * Another processor may allocate the objects in
3147 * the slab since we are not holding any locks.
3148 */
3149 if (!obj)
3150 goto retry;
3151 }
3152 }
3153
3154 if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie)))
3155 goto retry_cpuset;
3156 return obj;
3157 }
3158
3159 /*
3160 * A interface to enable slab creation on nodeid
3161 */
____cache_alloc_node(struct kmem_cache * cachep,gfp_t flags,int nodeid)3162 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
3163 int nodeid)
3164 {
3165 struct page *page;
3166 struct kmem_cache_node *n;
3167 void *obj = NULL;
3168 void *list = NULL;
3169
3170 VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES);
3171 n = get_node(cachep, nodeid);
3172 BUG_ON(!n);
3173
3174 check_irq_off();
3175 spin_lock(&n->list_lock);
3176 page = get_first_slab(n, false);
3177 if (!page)
3178 goto must_grow;
3179
3180 check_spinlock_acquired_node(cachep, nodeid);
3181
3182 STATS_INC_NODEALLOCS(cachep);
3183 STATS_INC_ACTIVE(cachep);
3184 STATS_SET_HIGH(cachep);
3185
3186 BUG_ON(page->active == cachep->num);
3187
3188 obj = slab_get_obj(cachep, page);
3189 n->free_objects--;
3190
3191 fixup_slab_list(cachep, n, page, &list);
3192
3193 spin_unlock(&n->list_lock);
3194 fixup_objfreelist_debug(cachep, &list);
3195 return obj;
3196
3197 must_grow:
3198 spin_unlock(&n->list_lock);
3199 page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid);
3200 if (page) {
3201 /* This slab isn't counted yet so don't update free_objects */
3202 obj = slab_get_obj(cachep, page);
3203 }
3204 cache_grow_end(cachep, page);
3205
3206 return obj ? obj : fallback_alloc(cachep, flags);
3207 }
3208
3209 static __always_inline void *
slab_alloc_node(struct kmem_cache * cachep,gfp_t flags,int nodeid,size_t orig_size,unsigned long caller)3210 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, size_t orig_size,
3211 unsigned long caller)
3212 {
3213 unsigned long save_flags;
3214 void *ptr;
3215 int slab_node = numa_mem_id();
3216 struct obj_cgroup *objcg = NULL;
3217 bool init = false;
3218
3219 flags &= gfp_allowed_mask;
3220 cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags);
3221 if (unlikely(!cachep))
3222 return NULL;
3223
3224 ptr = kfence_alloc(cachep, orig_size, flags);
3225 if (unlikely(ptr))
3226 goto out_hooks;
3227
3228 cache_alloc_debugcheck_before(cachep, flags);
3229 local_irq_save(save_flags);
3230
3231 if (nodeid == NUMA_NO_NODE)
3232 nodeid = slab_node;
3233
3234 if (unlikely(!get_node(cachep, nodeid))) {
3235 /* Node not bootstrapped yet */
3236 ptr = fallback_alloc(cachep, flags);
3237 goto out;
3238 }
3239
3240 if (nodeid == slab_node) {
3241 /*
3242 * Use the locally cached objects if possible.
3243 * However ____cache_alloc does not allow fallback
3244 * to other nodes. It may fail while we still have
3245 * objects on other nodes available.
3246 */
3247 ptr = ____cache_alloc(cachep, flags);
3248 if (ptr)
3249 goto out;
3250 }
3251 /* ___cache_alloc_node can fall back to other nodes */
3252 ptr = ____cache_alloc_node(cachep, flags, nodeid);
3253 out:
3254 local_irq_restore(save_flags);
3255 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
3256 init = slab_want_init_on_alloc(flags, cachep);
3257
3258 out_hooks:
3259 slab_post_alloc_hook(cachep, objcg, flags, 1, &ptr, init);
3260 return ptr;
3261 }
3262
3263 static __always_inline void *
__do_cache_alloc(struct kmem_cache * cache,gfp_t flags)3264 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
3265 {
3266 void *objp;
3267
3268 if (current->mempolicy || cpuset_do_slab_mem_spread()) {
3269 objp = alternate_node_alloc(cache, flags);
3270 if (objp)
3271 goto out;
3272 }
3273 objp = ____cache_alloc(cache, flags);
3274
3275 /*
3276 * We may just have run out of memory on the local node.
3277 * ____cache_alloc_node() knows how to locate memory on other nodes
3278 */
3279 if (!objp)
3280 objp = ____cache_alloc_node(cache, flags, numa_mem_id());
3281
3282 out:
3283 return objp;
3284 }
3285 #else
3286
3287 static __always_inline void *
__do_cache_alloc(struct kmem_cache * cachep,gfp_t flags)3288 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3289 {
3290 return ____cache_alloc(cachep, flags);
3291 }
3292
3293 #endif /* CONFIG_NUMA */
3294
3295 static __always_inline void *
slab_alloc(struct kmem_cache * cachep,gfp_t flags,size_t orig_size,unsigned long caller)3296 slab_alloc(struct kmem_cache *cachep, gfp_t flags, size_t orig_size, unsigned long caller)
3297 {
3298 unsigned long save_flags;
3299 void *objp;
3300 struct obj_cgroup *objcg = NULL;
3301 bool init = false;
3302
3303 flags &= gfp_allowed_mask;
3304 cachep = slab_pre_alloc_hook(cachep, &objcg, 1, flags);
3305 if (unlikely(!cachep))
3306 return NULL;
3307
3308 objp = kfence_alloc(cachep, orig_size, flags);
3309 if (unlikely(objp))
3310 goto out;
3311
3312 cache_alloc_debugcheck_before(cachep, flags);
3313 local_irq_save(save_flags);
3314 objp = __do_cache_alloc(cachep, flags);
3315 local_irq_restore(save_flags);
3316 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
3317 prefetchw(objp);
3318 init = slab_want_init_on_alloc(flags, cachep);
3319
3320 out:
3321 slab_post_alloc_hook(cachep, objcg, flags, 1, &objp, init);
3322 return objp;
3323 }
3324
3325 /*
3326 * Caller needs to acquire correct kmem_cache_node's list_lock
3327 * @list: List of detached free slabs should be freed by caller
3328 */
free_block(struct kmem_cache * cachep,void ** objpp,int nr_objects,int node,struct list_head * list)3329 static void free_block(struct kmem_cache *cachep, void **objpp,
3330 int nr_objects, int node, struct list_head *list)
3331 {
3332 int i;
3333 struct kmem_cache_node *n = get_node(cachep, node);
3334 struct page *page;
3335
3336 n->free_objects += nr_objects;
3337
3338 for (i = 0; i < nr_objects; i++) {
3339 void *objp;
3340 struct page *page;
3341
3342 objp = objpp[i];
3343
3344 page = virt_to_head_page(objp);
3345 list_del(&page->slab_list);
3346 check_spinlock_acquired_node(cachep, node);
3347 slab_put_obj(cachep, page, objp);
3348 STATS_DEC_ACTIVE(cachep);
3349
3350 /* fixup slab chains */
3351 if (page->active == 0) {
3352 list_add(&page->slab_list, &n->slabs_free);
3353 n->free_slabs++;
3354 } else {
3355 /* Unconditionally move a slab to the end of the
3356 * partial list on free - maximum time for the
3357 * other objects to be freed, too.
3358 */
3359 list_add_tail(&page->slab_list, &n->slabs_partial);
3360 }
3361 }
3362
3363 while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) {
3364 n->free_objects -= cachep->num;
3365
3366 page = list_last_entry(&n->slabs_free, struct page, slab_list);
3367 list_move(&page->slab_list, list);
3368 n->free_slabs--;
3369 n->total_slabs--;
3370 }
3371 }
3372
cache_flusharray(struct kmem_cache * cachep,struct array_cache * ac)3373 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
3374 {
3375 int batchcount;
3376 struct kmem_cache_node *n;
3377 int node = numa_mem_id();
3378 LIST_HEAD(list);
3379
3380 batchcount = ac->batchcount;
3381
3382 check_irq_off();
3383 n = get_node(cachep, node);
3384 spin_lock(&n->list_lock);
3385 if (n->shared) {
3386 struct array_cache *shared_array = n->shared;
3387 int max = shared_array->limit - shared_array->avail;
3388 if (max) {
3389 if (batchcount > max)
3390 batchcount = max;
3391 memcpy(&(shared_array->entry[shared_array->avail]),
3392 ac->entry, sizeof(void *) * batchcount);
3393 shared_array->avail += batchcount;
3394 goto free_done;
3395 }
3396 }
3397
3398 free_block(cachep, ac->entry, batchcount, node, &list);
3399 free_done:
3400 #if STATS
3401 {
3402 int i = 0;
3403 struct page *page;
3404
3405 list_for_each_entry(page, &n->slabs_free, slab_list) {
3406 BUG_ON(page->active);
3407
3408 i++;
3409 }
3410 STATS_SET_FREEABLE(cachep, i);
3411 }
3412 #endif
3413 spin_unlock(&n->list_lock);
3414 ac->avail -= batchcount;
3415 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
3416 slabs_destroy(cachep, &list);
3417 }
3418
3419 /*
3420 * Release an obj back to its cache. If the obj has a constructed state, it must
3421 * be in this state _before_ it is released. Called with disabled ints.
3422 */
__cache_free(struct kmem_cache * cachep,void * objp,unsigned long caller)3423 static __always_inline void __cache_free(struct kmem_cache *cachep, void *objp,
3424 unsigned long caller)
3425 {
3426 bool init;
3427
3428 if (is_kfence_address(objp)) {
3429 kmemleak_free_recursive(objp, cachep->flags);
3430 memcg_slab_free_hook(cachep, &objp, 1);
3431 __kfence_free(objp);
3432 return;
3433 }
3434
3435 /*
3436 * As memory initialization might be integrated into KASAN,
3437 * kasan_slab_free and initialization memset must be
3438 * kept together to avoid discrepancies in behavior.
3439 */
3440 init = slab_want_init_on_free(cachep);
3441 if (init && !kasan_has_integrated_init())
3442 memset(objp, 0, cachep->object_size);
3443 /* KASAN might put objp into memory quarantine, delaying its reuse. */
3444 if (kasan_slab_free(cachep, objp, init))
3445 return;
3446
3447 /* Use KCSAN to help debug racy use-after-free. */
3448 if (!(cachep->flags & SLAB_TYPESAFE_BY_RCU))
3449 __kcsan_check_access(objp, cachep->object_size,
3450 KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
3451
3452 ___cache_free(cachep, objp, caller);
3453 }
3454
___cache_free(struct kmem_cache * cachep,void * objp,unsigned long caller)3455 void ___cache_free(struct kmem_cache *cachep, void *objp,
3456 unsigned long caller)
3457 {
3458 struct array_cache *ac = cpu_cache_get(cachep);
3459
3460 check_irq_off();
3461 kmemleak_free_recursive(objp, cachep->flags);
3462 objp = cache_free_debugcheck(cachep, objp, caller);
3463 memcg_slab_free_hook(cachep, &objp, 1);
3464
3465 /*
3466 * Skip calling cache_free_alien() when the platform is not numa.
3467 * This will avoid cache misses that happen while accessing slabp (which
3468 * is per page memory reference) to get nodeid. Instead use a global
3469 * variable to skip the call, which is mostly likely to be present in
3470 * the cache.
3471 */
3472 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
3473 return;
3474
3475 if (ac->avail < ac->limit) {
3476 STATS_INC_FREEHIT(cachep);
3477 } else {
3478 STATS_INC_FREEMISS(cachep);
3479 cache_flusharray(cachep, ac);
3480 }
3481
3482 if (sk_memalloc_socks()) {
3483 struct page *page = virt_to_head_page(objp);
3484
3485 if (unlikely(PageSlabPfmemalloc(page))) {
3486 cache_free_pfmemalloc(cachep, page, objp);
3487 return;
3488 }
3489 }
3490
3491 __free_one(ac, objp);
3492 }
3493
3494 /**
3495 * kmem_cache_alloc - Allocate an object
3496 * @cachep: The cache to allocate from.
3497 * @flags: See kmalloc().
3498 *
3499 * Allocate an object from this cache. The flags are only relevant
3500 * if the cache has no available objects.
3501 *
3502 * Return: pointer to the new object or %NULL in case of error
3503 */
kmem_cache_alloc(struct kmem_cache * cachep,gfp_t flags)3504 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
3505 {
3506 void *ret = slab_alloc(cachep, flags, cachep->object_size, _RET_IP_);
3507
3508 trace_kmem_cache_alloc(_RET_IP_, ret,
3509 cachep->object_size, cachep->size, flags);
3510
3511 return ret;
3512 }
3513 EXPORT_SYMBOL(kmem_cache_alloc);
3514
3515 static __always_inline void
cache_alloc_debugcheck_after_bulk(struct kmem_cache * s,gfp_t flags,size_t size,void ** p,unsigned long caller)3516 cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags,
3517 size_t size, void **p, unsigned long caller)
3518 {
3519 size_t i;
3520
3521 for (i = 0; i < size; i++)
3522 p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller);
3523 }
3524
kmem_cache_alloc_bulk(struct kmem_cache * s,gfp_t flags,size_t size,void ** p)3525 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
3526 void **p)
3527 {
3528 size_t i;
3529 struct obj_cgroup *objcg = NULL;
3530
3531 s = slab_pre_alloc_hook(s, &objcg, size, flags);
3532 if (!s)
3533 return 0;
3534
3535 cache_alloc_debugcheck_before(s, flags);
3536
3537 local_irq_disable();
3538 for (i = 0; i < size; i++) {
3539 void *objp = kfence_alloc(s, s->object_size, flags) ?: __do_cache_alloc(s, flags);
3540
3541 if (unlikely(!objp))
3542 goto error;
3543 p[i] = objp;
3544 }
3545 local_irq_enable();
3546
3547 cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_);
3548
3549 /*
3550 * memcg and kmem_cache debug support and memory initialization.
3551 * Done outside of the IRQ disabled section.
3552 */
3553 slab_post_alloc_hook(s, objcg, flags, size, p,
3554 slab_want_init_on_alloc(flags, s));
3555 /* FIXME: Trace call missing. Christoph would like a bulk variant */
3556 return size;
3557 error:
3558 local_irq_enable();
3559 cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_);
3560 slab_post_alloc_hook(s, objcg, flags, i, p, false);
3561 __kmem_cache_free_bulk(s, i, p);
3562 return 0;
3563 }
3564 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
3565
3566 #ifdef CONFIG_TRACING
3567 void *
kmem_cache_alloc_trace(struct kmem_cache * cachep,gfp_t flags,size_t size)3568 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size)
3569 {
3570 void *ret;
3571
3572 ret = slab_alloc(cachep, flags, size, _RET_IP_);
3573
3574 ret = kasan_kmalloc(cachep, ret, size, flags);
3575 trace_kmalloc(_RET_IP_, ret,
3576 size, cachep->size, flags);
3577 return ret;
3578 }
3579 EXPORT_SYMBOL(kmem_cache_alloc_trace);
3580 #endif
3581
3582 #ifdef CONFIG_NUMA
3583 /**
3584 * kmem_cache_alloc_node - Allocate an object on the specified node
3585 * @cachep: The cache to allocate from.
3586 * @flags: See kmalloc().
3587 * @nodeid: node number of the target node.
3588 *
3589 * Identical to kmem_cache_alloc but it will allocate memory on the given
3590 * node, which can improve the performance for cpu bound structures.
3591 *
3592 * Fallback to other node is possible if __GFP_THISNODE is not set.
3593 *
3594 * Return: pointer to the new object or %NULL in case of error
3595 */
kmem_cache_alloc_node(struct kmem_cache * cachep,gfp_t flags,int nodeid)3596 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
3597 {
3598 void *ret = slab_alloc_node(cachep, flags, nodeid, cachep->object_size, _RET_IP_);
3599
3600 trace_kmem_cache_alloc_node(_RET_IP_, ret,
3601 cachep->object_size, cachep->size,
3602 flags, nodeid);
3603
3604 return ret;
3605 }
3606 EXPORT_SYMBOL(kmem_cache_alloc_node);
3607
3608 #ifdef CONFIG_TRACING
kmem_cache_alloc_node_trace(struct kmem_cache * cachep,gfp_t flags,int nodeid,size_t size)3609 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep,
3610 gfp_t flags,
3611 int nodeid,
3612 size_t size)
3613 {
3614 void *ret;
3615
3616 ret = slab_alloc_node(cachep, flags, nodeid, size, _RET_IP_);
3617
3618 ret = kasan_kmalloc(cachep, ret, size, flags);
3619 trace_kmalloc_node(_RET_IP_, ret,
3620 size, cachep->size,
3621 flags, nodeid);
3622 return ret;
3623 }
3624 EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
3625 #endif
3626
3627 static __always_inline void *
__do_kmalloc_node(size_t size,gfp_t flags,int node,unsigned long caller)3628 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller)
3629 {
3630 struct kmem_cache *cachep;
3631 void *ret;
3632
3633 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3634 return NULL;
3635 cachep = kmalloc_slab(size, flags);
3636 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3637 return cachep;
3638 ret = kmem_cache_alloc_node_trace(cachep, flags, node, size);
3639 ret = kasan_kmalloc(cachep, ret, size, flags);
3640
3641 return ret;
3642 }
3643
__kmalloc_node(size_t size,gfp_t flags,int node)3644 void *__kmalloc_node(size_t size, gfp_t flags, int node)
3645 {
3646 return __do_kmalloc_node(size, flags, node, _RET_IP_);
3647 }
3648 EXPORT_SYMBOL(__kmalloc_node);
3649
__kmalloc_node_track_caller(size_t size,gfp_t flags,int node,unsigned long caller)3650 void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
3651 int node, unsigned long caller)
3652 {
3653 return __do_kmalloc_node(size, flags, node, caller);
3654 }
3655 EXPORT_SYMBOL(__kmalloc_node_track_caller);
3656 #endif /* CONFIG_NUMA */
3657
3658 /**
3659 * __do_kmalloc - allocate memory
3660 * @size: how many bytes of memory are required.
3661 * @flags: the type of memory to allocate (see kmalloc).
3662 * @caller: function caller for debug tracking of the caller
3663 *
3664 * Return: pointer to the allocated memory or %NULL in case of error
3665 */
__do_kmalloc(size_t size,gfp_t flags,unsigned long caller)3666 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
3667 unsigned long caller)
3668 {
3669 struct kmem_cache *cachep;
3670 void *ret;
3671
3672 if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
3673 return NULL;
3674 cachep = kmalloc_slab(size, flags);
3675 if (unlikely(ZERO_OR_NULL_PTR(cachep)))
3676 return cachep;
3677 ret = slab_alloc(cachep, flags, size, caller);
3678
3679 ret = kasan_kmalloc(cachep, ret, size, flags);
3680 trace_kmalloc(caller, ret,
3681 size, cachep->size, flags);
3682
3683 return ret;
3684 }
3685
__kmalloc(size_t size,gfp_t flags)3686 void *__kmalloc(size_t size, gfp_t flags)
3687 {
3688 return __do_kmalloc(size, flags, _RET_IP_);
3689 }
3690 EXPORT_SYMBOL(__kmalloc);
3691
__kmalloc_track_caller(size_t size,gfp_t flags,unsigned long caller)3692 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
3693 {
3694 return __do_kmalloc(size, flags, caller);
3695 }
3696 EXPORT_SYMBOL(__kmalloc_track_caller);
3697
3698 /**
3699 * kmem_cache_free - Deallocate an object
3700 * @cachep: The cache the allocation was from.
3701 * @objp: The previously allocated object.
3702 *
3703 * Free an object which was previously allocated from this
3704 * cache.
3705 */
kmem_cache_free(struct kmem_cache * cachep,void * objp)3706 void kmem_cache_free(struct kmem_cache *cachep, void *objp)
3707 {
3708 unsigned long flags;
3709 cachep = cache_from_obj(cachep, objp);
3710 if (!cachep)
3711 return;
3712
3713 local_irq_save(flags);
3714 debug_check_no_locks_freed(objp, cachep->object_size);
3715 if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
3716 debug_check_no_obj_freed(objp, cachep->object_size);
3717 __cache_free(cachep, objp, _RET_IP_);
3718 local_irq_restore(flags);
3719
3720 trace_kmem_cache_free(_RET_IP_, objp);
3721 }
3722 EXPORT_SYMBOL(kmem_cache_free);
3723
kmem_cache_free_bulk(struct kmem_cache * orig_s,size_t size,void ** p)3724 void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p)
3725 {
3726 struct kmem_cache *s;
3727 size_t i;
3728
3729 local_irq_disable();
3730 for (i = 0; i < size; i++) {
3731 void *objp = p[i];
3732
3733 if (!orig_s) /* called via kfree_bulk */
3734 s = virt_to_cache(objp);
3735 else
3736 s = cache_from_obj(orig_s, objp);
3737 if (!s)
3738 continue;
3739
3740 debug_check_no_locks_freed(objp, s->object_size);
3741 if (!(s->flags & SLAB_DEBUG_OBJECTS))
3742 debug_check_no_obj_freed(objp, s->object_size);
3743
3744 __cache_free(s, objp, _RET_IP_);
3745 }
3746 local_irq_enable();
3747
3748 /* FIXME: add tracing */
3749 }
3750 EXPORT_SYMBOL(kmem_cache_free_bulk);
3751
3752 /**
3753 * kfree - free previously allocated memory
3754 * @objp: pointer returned by kmalloc.
3755 *
3756 * If @objp is NULL, no operation is performed.
3757 *
3758 * Don't free memory not originally allocated by kmalloc()
3759 * or you will run into trouble.
3760 */
kfree(const void * objp)3761 void kfree(const void *objp)
3762 {
3763 struct kmem_cache *c;
3764 unsigned long flags;
3765
3766 trace_kfree(_RET_IP_, objp);
3767
3768 if (unlikely(ZERO_OR_NULL_PTR(objp)))
3769 return;
3770 local_irq_save(flags);
3771 kfree_debugcheck(objp);
3772 c = virt_to_cache(objp);
3773 if (!c) {
3774 local_irq_restore(flags);
3775 return;
3776 }
3777 debug_check_no_locks_freed(objp, c->object_size);
3778
3779 debug_check_no_obj_freed(objp, c->object_size);
3780 __cache_free(c, (void *)objp, _RET_IP_);
3781 local_irq_restore(flags);
3782 }
3783 EXPORT_SYMBOL(kfree);
3784
3785 /*
3786 * This initializes kmem_cache_node or resizes various caches for all nodes.
3787 */
setup_kmem_cache_nodes(struct kmem_cache * cachep,gfp_t gfp)3788 static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp)
3789 {
3790 int ret;
3791 int node;
3792 struct kmem_cache_node *n;
3793
3794 for_each_online_node(node) {
3795 ret = setup_kmem_cache_node(cachep, node, gfp, true);
3796 if (ret)
3797 goto fail;
3798
3799 }
3800
3801 return 0;
3802
3803 fail:
3804 if (!cachep->list.next) {
3805 /* Cache is not active yet. Roll back what we did */
3806 node--;
3807 while (node >= 0) {
3808 n = get_node(cachep, node);
3809 if (n) {
3810 kfree(n->shared);
3811 free_alien_cache(n->alien);
3812 kfree(n);
3813 cachep->node[node] = NULL;
3814 }
3815 node--;
3816 }
3817 }
3818 return -ENOMEM;
3819 }
3820
3821 /* Always called with the slab_mutex held */
do_tune_cpucache(struct kmem_cache * cachep,int limit,int batchcount,int shared,gfp_t gfp)3822 static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
3823 int batchcount, int shared, gfp_t gfp)
3824 {
3825 struct array_cache __percpu *cpu_cache, *prev;
3826 int cpu;
3827
3828 cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount);
3829 if (!cpu_cache)
3830 return -ENOMEM;
3831
3832 prev = cachep->cpu_cache;
3833 cachep->cpu_cache = cpu_cache;
3834 /*
3835 * Without a previous cpu_cache there's no need to synchronize remote
3836 * cpus, so skip the IPIs.
3837 */
3838 if (prev)
3839 kick_all_cpus_sync();
3840
3841 check_irq_on();
3842 cachep->batchcount = batchcount;
3843 cachep->limit = limit;
3844 cachep->shared = shared;
3845
3846 if (!prev)
3847 goto setup_node;
3848
3849 for_each_online_cpu(cpu) {
3850 LIST_HEAD(list);
3851 int node;
3852 struct kmem_cache_node *n;
3853 struct array_cache *ac = per_cpu_ptr(prev, cpu);
3854
3855 node = cpu_to_mem(cpu);
3856 n = get_node(cachep, node);
3857 spin_lock_irq(&n->list_lock);
3858 free_block(cachep, ac->entry, ac->avail, node, &list);
3859 spin_unlock_irq(&n->list_lock);
3860 slabs_destroy(cachep, &list);
3861 }
3862 free_percpu(prev);
3863
3864 setup_node:
3865 return setup_kmem_cache_nodes(cachep, gfp);
3866 }
3867
3868 /* Called with slab_mutex held always */
enable_cpucache(struct kmem_cache * cachep,gfp_t gfp)3869 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp)
3870 {
3871 int err;
3872 int limit = 0;
3873 int shared = 0;
3874 int batchcount = 0;
3875
3876 err = cache_random_seq_create(cachep, cachep->num, gfp);
3877 if (err)
3878 goto end;
3879
3880 if (limit && shared && batchcount)
3881 goto skip_setup;
3882 /*
3883 * The head array serves three purposes:
3884 * - create a LIFO ordering, i.e. return objects that are cache-warm
3885 * - reduce the number of spinlock operations.
3886 * - reduce the number of linked list operations on the slab and
3887 * bufctl chains: array operations are cheaper.
3888 * The numbers are guessed, we should auto-tune as described by
3889 * Bonwick.
3890 */
3891 if (cachep->size > 131072)
3892 limit = 1;
3893 else if (cachep->size > PAGE_SIZE)
3894 limit = 8;
3895 else if (cachep->size > 1024)
3896 limit = 24;
3897 else if (cachep->size > 256)
3898 limit = 54;
3899 else
3900 limit = 120;
3901
3902 /*
3903 * CPU bound tasks (e.g. network routing) can exhibit cpu bound
3904 * allocation behaviour: Most allocs on one cpu, most free operations
3905 * on another cpu. For these cases, an efficient object passing between
3906 * cpus is necessary. This is provided by a shared array. The array
3907 * replaces Bonwick's magazine layer.
3908 * On uniprocessor, it's functionally equivalent (but less efficient)
3909 * to a larger limit. Thus disabled by default.
3910 */
3911 shared = 0;
3912 if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1)
3913 shared = 8;
3914
3915 #if DEBUG
3916 /*
3917 * With debugging enabled, large batchcount lead to excessively long
3918 * periods with disabled local interrupts. Limit the batchcount
3919 */
3920 if (limit > 32)
3921 limit = 32;
3922 #endif
3923 batchcount = (limit + 1) / 2;
3924 skip_setup:
3925 err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp);
3926 end:
3927 if (err)
3928 pr_err("enable_cpucache failed for %s, error %d\n",
3929 cachep->name, -err);
3930 return err;
3931 }
3932
3933 /*
3934 * Drain an array if it contains any elements taking the node lock only if
3935 * necessary. Note that the node listlock also protects the array_cache
3936 * if drain_array() is used on the shared array.
3937 */
drain_array(struct kmem_cache * cachep,struct kmem_cache_node * n,struct array_cache * ac,int node)3938 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
3939 struct array_cache *ac, int node)
3940 {
3941 LIST_HEAD(list);
3942
3943 /* ac from n->shared can be freed if we don't hold the slab_mutex. */
3944 check_mutex_acquired();
3945
3946 if (!ac || !ac->avail)
3947 return;
3948
3949 if (ac->touched) {
3950 ac->touched = 0;
3951 return;
3952 }
3953
3954 spin_lock_irq(&n->list_lock);
3955 drain_array_locked(cachep, ac, node, false, &list);
3956 spin_unlock_irq(&n->list_lock);
3957
3958 slabs_destroy(cachep, &list);
3959 }
3960
3961 /**
3962 * cache_reap - Reclaim memory from caches.
3963 * @w: work descriptor
3964 *
3965 * Called from workqueue/eventd every few seconds.
3966 * Purpose:
3967 * - clear the per-cpu caches for this CPU.
3968 * - return freeable pages to the main free memory pool.
3969 *
3970 * If we cannot acquire the cache chain mutex then just give up - we'll try
3971 * again on the next iteration.
3972 */
cache_reap(struct work_struct * w)3973 static void cache_reap(struct work_struct *w)
3974 {
3975 struct kmem_cache *searchp;
3976 struct kmem_cache_node *n;
3977 int node = numa_mem_id();
3978 struct delayed_work *work = to_delayed_work(w);
3979
3980 if (!mutex_trylock(&slab_mutex))
3981 /* Give up. Setup the next iteration. */
3982 goto out;
3983
3984 list_for_each_entry(searchp, &slab_caches, list) {
3985 check_irq_on();
3986
3987 /*
3988 * We only take the node lock if absolutely necessary and we
3989 * have established with reasonable certainty that
3990 * we can do some work if the lock was obtained.
3991 */
3992 n = get_node(searchp, node);
3993
3994 reap_alien(searchp, n);
3995
3996 drain_array(searchp, n, cpu_cache_get(searchp), node);
3997
3998 /*
3999 * These are racy checks but it does not matter
4000 * if we skip one check or scan twice.
4001 */
4002 if (time_after(n->next_reap, jiffies))
4003 goto next;
4004
4005 n->next_reap = jiffies + REAPTIMEOUT_NODE;
4006
4007 drain_array(searchp, n, n->shared, node);
4008
4009 if (n->free_touched)
4010 n->free_touched = 0;
4011 else {
4012 int freed;
4013
4014 freed = drain_freelist(searchp, n, (n->free_limit +
4015 5 * searchp->num - 1) / (5 * searchp->num));
4016 STATS_ADD_REAPED(searchp, freed);
4017 }
4018 next:
4019 cond_resched();
4020 }
4021 check_irq_on();
4022 mutex_unlock(&slab_mutex);
4023 next_reap_node();
4024 out:
4025 /* Set up the next iteration */
4026 schedule_delayed_work_on(smp_processor_id(), work,
4027 round_jiffies_relative(REAPTIMEOUT_AC));
4028 }
4029
get_slabinfo(struct kmem_cache * cachep,struct slabinfo * sinfo)4030 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo)
4031 {
4032 unsigned long active_objs, num_objs, active_slabs;
4033 unsigned long total_slabs = 0, free_objs = 0, shared_avail = 0;
4034 unsigned long free_slabs = 0;
4035 int node;
4036 struct kmem_cache_node *n;
4037
4038 for_each_kmem_cache_node(cachep, node, n) {
4039 check_irq_on();
4040 spin_lock_irq(&n->list_lock);
4041
4042 total_slabs += n->total_slabs;
4043 free_slabs += n->free_slabs;
4044 free_objs += n->free_objects;
4045
4046 if (n->shared)
4047 shared_avail += n->shared->avail;
4048
4049 spin_unlock_irq(&n->list_lock);
4050 }
4051 num_objs = total_slabs * cachep->num;
4052 active_slabs = total_slabs - free_slabs;
4053 active_objs = num_objs - free_objs;
4054
4055 sinfo->active_objs = active_objs;
4056 sinfo->num_objs = num_objs;
4057 sinfo->active_slabs = active_slabs;
4058 sinfo->num_slabs = total_slabs;
4059 sinfo->shared_avail = shared_avail;
4060 sinfo->limit = cachep->limit;
4061 sinfo->batchcount = cachep->batchcount;
4062 sinfo->shared = cachep->shared;
4063 sinfo->objects_per_slab = cachep->num;
4064 sinfo->cache_order = cachep->gfporder;
4065 }
4066 EXPORT_SYMBOL_GPL(get_slabinfo);
4067
slabinfo_show_stats(struct seq_file * m,struct kmem_cache * cachep)4068 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep)
4069 {
4070 #if STATS
4071 { /* node stats */
4072 unsigned long high = cachep->high_mark;
4073 unsigned long allocs = cachep->num_allocations;
4074 unsigned long grown = cachep->grown;
4075 unsigned long reaped = cachep->reaped;
4076 unsigned long errors = cachep->errors;
4077 unsigned long max_freeable = cachep->max_freeable;
4078 unsigned long node_allocs = cachep->node_allocs;
4079 unsigned long node_frees = cachep->node_frees;
4080 unsigned long overflows = cachep->node_overflow;
4081
4082 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu",
4083 allocs, high, grown,
4084 reaped, errors, max_freeable, node_allocs,
4085 node_frees, overflows);
4086 }
4087 /* cpu stats */
4088 {
4089 unsigned long allochit = atomic_read(&cachep->allochit);
4090 unsigned long allocmiss = atomic_read(&cachep->allocmiss);
4091 unsigned long freehit = atomic_read(&cachep->freehit);
4092 unsigned long freemiss = atomic_read(&cachep->freemiss);
4093
4094 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu",
4095 allochit, allocmiss, freehit, freemiss);
4096 }
4097 #endif
4098 }
4099
4100 #define MAX_SLABINFO_WRITE 128
4101 /**
4102 * slabinfo_write - Tuning for the slab allocator
4103 * @file: unused
4104 * @buffer: user buffer
4105 * @count: data length
4106 * @ppos: unused
4107 *
4108 * Return: %0 on success, negative error code otherwise.
4109 */
slabinfo_write(struct file * file,const char __user * buffer,size_t count,loff_t * ppos)4110 ssize_t slabinfo_write(struct file *file, const char __user *buffer,
4111 size_t count, loff_t *ppos)
4112 {
4113 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp;
4114 int limit, batchcount, shared, res;
4115 struct kmem_cache *cachep;
4116
4117 if (count > MAX_SLABINFO_WRITE)
4118 return -EINVAL;
4119 if (copy_from_user(&kbuf, buffer, count))
4120 return -EFAULT;
4121 kbuf[MAX_SLABINFO_WRITE] = '\0';
4122
4123 tmp = strchr(kbuf, ' ');
4124 if (!tmp)
4125 return -EINVAL;
4126 *tmp = '\0';
4127 tmp++;
4128 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3)
4129 return -EINVAL;
4130
4131 /* Find the cache in the chain of caches. */
4132 mutex_lock(&slab_mutex);
4133 res = -EINVAL;
4134 list_for_each_entry(cachep, &slab_caches, list) {
4135 if (!strcmp(cachep->name, kbuf)) {
4136 if (limit < 1 || batchcount < 1 ||
4137 batchcount > limit || shared < 0) {
4138 res = 0;
4139 } else {
4140 res = do_tune_cpucache(cachep, limit,
4141 batchcount, shared,
4142 GFP_KERNEL);
4143 }
4144 break;
4145 }
4146 }
4147 mutex_unlock(&slab_mutex);
4148 if (res >= 0)
4149 res = count;
4150 return res;
4151 }
4152
4153 #ifdef CONFIG_HARDENED_USERCOPY
4154 /*
4155 * Rejects incorrectly sized objects and objects that are to be copied
4156 * to/from userspace but do not fall entirely within the containing slab
4157 * cache's usercopy region.
4158 *
4159 * Returns NULL if check passes, otherwise const char * to name of cache
4160 * to indicate an error.
4161 */
__check_heap_object(const void * ptr,unsigned long n,struct page * page,bool to_user)4162 void __check_heap_object(const void *ptr, unsigned long n, struct page *page,
4163 bool to_user)
4164 {
4165 struct kmem_cache *cachep;
4166 unsigned int objnr;
4167 unsigned long offset;
4168
4169 ptr = kasan_reset_tag(ptr);
4170
4171 /* Find and validate object. */
4172 cachep = page->slab_cache;
4173 objnr = obj_to_index(cachep, page, (void *)ptr);
4174 BUG_ON(objnr >= cachep->num);
4175
4176 /* Find offset within object. */
4177 if (is_kfence_address(ptr))
4178 offset = ptr - kfence_object_start(ptr);
4179 else
4180 offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep);
4181
4182 /* Allow address range falling entirely within usercopy region. */
4183 if (offset >= cachep->useroffset &&
4184 offset - cachep->useroffset <= cachep->usersize &&
4185 n <= cachep->useroffset - offset + cachep->usersize)
4186 return;
4187
4188 /*
4189 * If the copy is still within the allocated object, produce
4190 * a warning instead of rejecting the copy. This is intended
4191 * to be a temporary method to find any missing usercopy
4192 * whitelists.
4193 */
4194 if (usercopy_fallback &&
4195 offset <= cachep->object_size &&
4196 n <= cachep->object_size - offset) {
4197 usercopy_warn("SLAB object", cachep->name, to_user, offset, n);
4198 return;
4199 }
4200
4201 usercopy_abort("SLAB object", cachep->name, to_user, offset, n);
4202 }
4203 #endif /* CONFIG_HARDENED_USERCOPY */
4204
4205 /**
4206 * __ksize -- Uninstrumented ksize.
4207 * @objp: pointer to the object
4208 *
4209 * Unlike ksize(), __ksize() is uninstrumented, and does not provide the same
4210 * safety checks as ksize() with KASAN instrumentation enabled.
4211 *
4212 * Return: size of the actual memory used by @objp in bytes
4213 */
__ksize(const void * objp)4214 size_t __ksize(const void *objp)
4215 {
4216 struct kmem_cache *c;
4217 size_t size;
4218
4219 BUG_ON(!objp);
4220 if (unlikely(objp == ZERO_SIZE_PTR))
4221 return 0;
4222
4223 c = virt_to_cache(objp);
4224 size = c ? c->object_size : 0;
4225
4226 return size;
4227 }
4228 EXPORT_SYMBOL(__ksize);
4229