1 /* 2 * linux/mm/slab.c 3 * Written by Mark Hemment, 1996/97. 4 * (markhe@nextd.demon.co.uk) 5 * 6 * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli 7 * 8 * Major cleanup, different bufctl logic, per-cpu arrays 9 * (c) 2000 Manfred Spraul 10 * 11 * Cleanup, make the head arrays unconditional, preparation for NUMA 12 * (c) 2002 Manfred Spraul 13 * 14 * An implementation of the Slab Allocator as described in outline in; 15 * UNIX Internals: The New Frontiers by Uresh Vahalia 16 * Pub: Prentice Hall ISBN 0-13-101908-2 17 * or with a little more detail in; 18 * The Slab Allocator: An Object-Caching Kernel Memory Allocator 19 * Jeff Bonwick (Sun Microsystems). 20 * Presented at: USENIX Summer 1994 Technical Conference 21 * 22 * The memory is organized in caches, one cache for each object type. 23 * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct) 24 * Each cache consists out of many slabs (they are small (usually one 25 * page long) and always contiguous), and each slab contains multiple 26 * initialized objects. 27 * 28 * This means, that your constructor is used only for newly allocated 29 * slabs and you must pass objects with the same initializations to 30 * kmem_cache_free. 31 * 32 * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM, 33 * normal). If you need a special memory type, then must create a new 34 * cache for that memory type. 35 * 36 * In order to reduce fragmentation, the slabs are sorted in 3 groups: 37 * full slabs with 0 free objects 38 * partial slabs 39 * empty slabs with no allocated objects 40 * 41 * If partial slabs exist, then new allocations come from these slabs, 42 * otherwise from empty slabs or new slabs are allocated. 43 * 44 * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache 45 * during kmem_cache_destroy(). The caller must prevent concurrent allocs. 46 * 47 * Each cache has a short per-cpu head array, most allocs 48 * and frees go into that array, and if that array overflows, then 1/2 49 * of the entries in the array are given back into the global cache. 50 * The head array is strictly LIFO and should improve the cache hit rates. 51 * On SMP, it additionally reduces the spinlock operations. 52 * 53 * The c_cpuarray may not be read with enabled local interrupts - 54 * it's changed with a smp_call_function(). 55 * 56 * SMP synchronization: 57 * constructors and destructors are called without any locking. 58 * Several members in struct kmem_cache and struct slab never change, they 59 * are accessed without any locking. 60 * The per-cpu arrays are never accessed from the wrong cpu, no locking, 61 * and local interrupts are disabled so slab code is preempt-safe. 62 * The non-constant members are protected with a per-cache irq spinlock. 63 * 64 * Many thanks to Mark Hemment, who wrote another per-cpu slab patch 65 * in 2000 - many ideas in the current implementation are derived from 66 * his patch. 67 * 68 * Further notes from the original documentation: 69 * 70 * 11 April '97. Started multi-threading - markhe 71 * The global cache-chain is protected by the mutex 'slab_mutex'. 72 * The sem is only needed when accessing/extending the cache-chain, which 73 * can never happen inside an interrupt (kmem_cache_create(), 74 * kmem_cache_shrink() and kmem_cache_reap()). 75 * 76 * At present, each engine can be growing a cache. This should be blocked. 77 * 78 * 15 March 2005. NUMA slab allocator. 79 * Shai Fultheim <shai@scalex86.org>. 80 * Shobhit Dayal <shobhit@calsoftinc.com> 81 * Alok N Kataria <alokk@calsoftinc.com> 82 * Christoph Lameter <christoph@lameter.com> 83 * 84 * Modified the slab allocator to be node aware on NUMA systems. 85 * Each node has its own list of partial, free and full slabs. 86 * All object allocations for a node occur from node specific slab lists. 87 */ 88 89 #include <linux/slab.h> 90 #include <linux/mm.h> 91 #include <linux/poison.h> 92 #include <linux/swap.h> 93 #include <linux/cache.h> 94 #include <linux/interrupt.h> 95 #include <linux/init.h> 96 #include <linux/compiler.h> 97 #include <linux/cpuset.h> 98 #include <linux/proc_fs.h> 99 #include <linux/seq_file.h> 100 #include <linux/notifier.h> 101 #include <linux/kallsyms.h> 102 #include <linux/cpu.h> 103 #include <linux/sysctl.h> 104 #include <linux/module.h> 105 #include <linux/rcupdate.h> 106 #include <linux/string.h> 107 #include <linux/uaccess.h> 108 #include <linux/nodemask.h> 109 #include <linux/kmemleak.h> 110 #include <linux/mempolicy.h> 111 #include <linux/mutex.h> 112 #include <linux/fault-inject.h> 113 #include <linux/rtmutex.h> 114 #include <linux/reciprocal_div.h> 115 #include <linux/debugobjects.h> 116 #include <linux/kmemcheck.h> 117 #include <linux/memory.h> 118 #include <linux/prefetch.h> 119 120 #include <net/sock.h> 121 122 #include <asm/cacheflush.h> 123 #include <asm/tlbflush.h> 124 #include <asm/page.h> 125 126 #include <trace/events/kmem.h> 127 128 #include "internal.h" 129 130 #include "slab.h" 131 132 /* 133 * DEBUG - 1 for kmem_cache_create() to honour; SLAB_RED_ZONE & SLAB_POISON. 134 * 0 for faster, smaller code (especially in the critical paths). 135 * 136 * STATS - 1 to collect stats for /proc/slabinfo. 137 * 0 for faster, smaller code (especially in the critical paths). 138 * 139 * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible) 140 */ 141 142 #ifdef CONFIG_DEBUG_SLAB 143 #define DEBUG 1 144 #define STATS 1 145 #define FORCED_DEBUG 1 146 #else 147 #define DEBUG 0 148 #define STATS 0 149 #define FORCED_DEBUG 0 150 #endif 151 152 /* Shouldn't this be in a header file somewhere? */ 153 #define BYTES_PER_WORD sizeof(void *) 154 #define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long)) 155 156 #ifndef ARCH_KMALLOC_FLAGS 157 #define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN 158 #endif 159 160 #define FREELIST_BYTE_INDEX (((PAGE_SIZE >> BITS_PER_BYTE) \ 161 <= SLAB_OBJ_MIN_SIZE) ? 1 : 0) 162 163 #if FREELIST_BYTE_INDEX 164 typedef unsigned char freelist_idx_t; 165 #else 166 typedef unsigned short freelist_idx_t; 167 #endif 168 169 #define SLAB_OBJ_MAX_NUM ((1 << sizeof(freelist_idx_t) * BITS_PER_BYTE) - 1) 170 171 /* 172 * struct array_cache 173 * 174 * Purpose: 175 * - LIFO ordering, to hand out cache-warm objects from _alloc 176 * - reduce the number of linked list operations 177 * - reduce spinlock operations 178 * 179 * The limit is stored in the per-cpu structure to reduce the data cache 180 * footprint. 181 * 182 */ 183 struct array_cache { 184 unsigned int avail; 185 unsigned int limit; 186 unsigned int batchcount; 187 unsigned int touched; 188 void *entry[]; /* 189 * Must have this definition in here for the proper 190 * alignment of array_cache. Also simplifies accessing 191 * the entries. 192 */ 193 }; 194 195 struct alien_cache { 196 spinlock_t lock; 197 struct array_cache ac; 198 }; 199 200 /* 201 * Need this for bootstrapping a per node allocator. 202 */ 203 #define NUM_INIT_LISTS (2 * MAX_NUMNODES) 204 static struct kmem_cache_node __initdata init_kmem_cache_node[NUM_INIT_LISTS]; 205 #define CACHE_CACHE 0 206 #define SIZE_NODE (MAX_NUMNODES) 207 208 static int drain_freelist(struct kmem_cache *cache, 209 struct kmem_cache_node *n, int tofree); 210 static void free_block(struct kmem_cache *cachep, void **objpp, int len, 211 int node, struct list_head *list); 212 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list); 213 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp); 214 static void cache_reap(struct work_struct *unused); 215 216 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, 217 void **list); 218 static inline void fixup_slab_list(struct kmem_cache *cachep, 219 struct kmem_cache_node *n, struct page *page, 220 void **list); 221 static int slab_early_init = 1; 222 223 #define INDEX_NODE kmalloc_index(sizeof(struct kmem_cache_node)) 224 225 static void kmem_cache_node_init(struct kmem_cache_node *parent) 226 { 227 INIT_LIST_HEAD(&parent->slabs_full); 228 INIT_LIST_HEAD(&parent->slabs_partial); 229 INIT_LIST_HEAD(&parent->slabs_free); 230 parent->shared = NULL; 231 parent->alien = NULL; 232 parent->colour_next = 0; 233 spin_lock_init(&parent->list_lock); 234 parent->free_objects = 0; 235 parent->free_touched = 0; 236 parent->num_slabs = 0; 237 } 238 239 #define MAKE_LIST(cachep, listp, slab, nodeid) \ 240 do { \ 241 INIT_LIST_HEAD(listp); \ 242 list_splice(&get_node(cachep, nodeid)->slab, listp); \ 243 } while (0) 244 245 #define MAKE_ALL_LISTS(cachep, ptr, nodeid) \ 246 do { \ 247 MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \ 248 MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \ 249 MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \ 250 } while (0) 251 252 #define CFLGS_OBJFREELIST_SLAB (0x40000000UL) 253 #define CFLGS_OFF_SLAB (0x80000000UL) 254 #define OBJFREELIST_SLAB(x) ((x)->flags & CFLGS_OBJFREELIST_SLAB) 255 #define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) 256 257 #define BATCHREFILL_LIMIT 16 258 /* 259 * Optimization question: fewer reaps means less probability for unnessary 260 * cpucache drain/refill cycles. 261 * 262 * OTOH the cpuarrays can contain lots of objects, 263 * which could lock up otherwise freeable slabs. 264 */ 265 #define REAPTIMEOUT_AC (2*HZ) 266 #define REAPTIMEOUT_NODE (4*HZ) 267 268 #if STATS 269 #define STATS_INC_ACTIVE(x) ((x)->num_active++) 270 #define STATS_DEC_ACTIVE(x) ((x)->num_active--) 271 #define STATS_INC_ALLOCED(x) ((x)->num_allocations++) 272 #define STATS_INC_GROWN(x) ((x)->grown++) 273 #define STATS_ADD_REAPED(x,y) ((x)->reaped += (y)) 274 #define STATS_SET_HIGH(x) \ 275 do { \ 276 if ((x)->num_active > (x)->high_mark) \ 277 (x)->high_mark = (x)->num_active; \ 278 } while (0) 279 #define STATS_INC_ERR(x) ((x)->errors++) 280 #define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++) 281 #define STATS_INC_NODEFREES(x) ((x)->node_frees++) 282 #define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++) 283 #define STATS_SET_FREEABLE(x, i) \ 284 do { \ 285 if ((x)->max_freeable < i) \ 286 (x)->max_freeable = i; \ 287 } while (0) 288 #define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit) 289 #define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss) 290 #define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit) 291 #define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss) 292 #else 293 #define STATS_INC_ACTIVE(x) do { } while (0) 294 #define STATS_DEC_ACTIVE(x) do { } while (0) 295 #define STATS_INC_ALLOCED(x) do { } while (0) 296 #define STATS_INC_GROWN(x) do { } while (0) 297 #define STATS_ADD_REAPED(x,y) do { (void)(y); } while (0) 298 #define STATS_SET_HIGH(x) do { } while (0) 299 #define STATS_INC_ERR(x) do { } while (0) 300 #define STATS_INC_NODEALLOCS(x) do { } while (0) 301 #define STATS_INC_NODEFREES(x) do { } while (0) 302 #define STATS_INC_ACOVERFLOW(x) do { } while (0) 303 #define STATS_SET_FREEABLE(x, i) do { } while (0) 304 #define STATS_INC_ALLOCHIT(x) do { } while (0) 305 #define STATS_INC_ALLOCMISS(x) do { } while (0) 306 #define STATS_INC_FREEHIT(x) do { } while (0) 307 #define STATS_INC_FREEMISS(x) do { } while (0) 308 #endif 309 310 #if DEBUG 311 312 /* 313 * memory layout of objects: 314 * 0 : objp 315 * 0 .. cachep->obj_offset - BYTES_PER_WORD - 1: padding. This ensures that 316 * the end of an object is aligned with the end of the real 317 * allocation. Catches writes behind the end of the allocation. 318 * cachep->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1: 319 * redzone word. 320 * cachep->obj_offset: The real object. 321 * cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long] 322 * cachep->size - 1* BYTES_PER_WORD: last caller address 323 * [BYTES_PER_WORD long] 324 */ 325 static int obj_offset(struct kmem_cache *cachep) 326 { 327 return cachep->obj_offset; 328 } 329 330 static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp) 331 { 332 BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); 333 return (unsigned long long*) (objp + obj_offset(cachep) - 334 sizeof(unsigned long long)); 335 } 336 337 static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp) 338 { 339 BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); 340 if (cachep->flags & SLAB_STORE_USER) 341 return (unsigned long long *)(objp + cachep->size - 342 sizeof(unsigned long long) - 343 REDZONE_ALIGN); 344 return (unsigned long long *) (objp + cachep->size - 345 sizeof(unsigned long long)); 346 } 347 348 static void **dbg_userword(struct kmem_cache *cachep, void *objp) 349 { 350 BUG_ON(!(cachep->flags & SLAB_STORE_USER)); 351 return (void **)(objp + cachep->size - BYTES_PER_WORD); 352 } 353 354 #else 355 356 #define obj_offset(x) 0 357 #define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) 358 #define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;}) 359 #define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;}) 360 361 #endif 362 363 #ifdef CONFIG_DEBUG_SLAB_LEAK 364 365 static inline bool is_store_user_clean(struct kmem_cache *cachep) 366 { 367 return atomic_read(&cachep->store_user_clean) == 1; 368 } 369 370 static inline void set_store_user_clean(struct kmem_cache *cachep) 371 { 372 atomic_set(&cachep->store_user_clean, 1); 373 } 374 375 static inline void set_store_user_dirty(struct kmem_cache *cachep) 376 { 377 if (is_store_user_clean(cachep)) 378 atomic_set(&cachep->store_user_clean, 0); 379 } 380 381 #else 382 static inline void set_store_user_dirty(struct kmem_cache *cachep) {} 383 384 #endif 385 386 /* 387 * Do not go above this order unless 0 objects fit into the slab or 388 * overridden on the command line. 389 */ 390 #define SLAB_MAX_ORDER_HI 1 391 #define SLAB_MAX_ORDER_LO 0 392 static int slab_max_order = SLAB_MAX_ORDER_LO; 393 static bool slab_max_order_set __initdata; 394 395 static inline struct kmem_cache *virt_to_cache(const void *obj) 396 { 397 struct page *page = virt_to_head_page(obj); 398 return page->slab_cache; 399 } 400 401 static inline void *index_to_obj(struct kmem_cache *cache, struct page *page, 402 unsigned int idx) 403 { 404 return page->s_mem + cache->size * idx; 405 } 406 407 /* 408 * We want to avoid an expensive divide : (offset / cache->size) 409 * Using the fact that size is a constant for a particular cache, 410 * we can replace (offset / cache->size) by 411 * reciprocal_divide(offset, cache->reciprocal_buffer_size) 412 */ 413 static inline unsigned int obj_to_index(const struct kmem_cache *cache, 414 const struct page *page, void *obj) 415 { 416 u32 offset = (obj - page->s_mem); 417 return reciprocal_divide(offset, cache->reciprocal_buffer_size); 418 } 419 420 #define BOOT_CPUCACHE_ENTRIES 1 421 /* internal cache of cache description objs */ 422 static struct kmem_cache kmem_cache_boot = { 423 .batchcount = 1, 424 .limit = BOOT_CPUCACHE_ENTRIES, 425 .shared = 1, 426 .size = sizeof(struct kmem_cache), 427 .name = "kmem_cache", 428 }; 429 430 static DEFINE_PER_CPU(struct delayed_work, slab_reap_work); 431 432 static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep) 433 { 434 return this_cpu_ptr(cachep->cpu_cache); 435 } 436 437 /* 438 * Calculate the number of objects and left-over bytes for a given buffer size. 439 */ 440 static unsigned int cache_estimate(unsigned long gfporder, size_t buffer_size, 441 unsigned long flags, size_t *left_over) 442 { 443 unsigned int num; 444 size_t slab_size = PAGE_SIZE << gfporder; 445 446 /* 447 * The slab management structure can be either off the slab or 448 * on it. For the latter case, the memory allocated for a 449 * slab is used for: 450 * 451 * - @buffer_size bytes for each object 452 * - One freelist_idx_t for each object 453 * 454 * We don't need to consider alignment of freelist because 455 * freelist will be at the end of slab page. The objects will be 456 * at the correct alignment. 457 * 458 * If the slab management structure is off the slab, then the 459 * alignment will already be calculated into the size. Because 460 * the slabs are all pages aligned, the objects will be at the 461 * correct alignment when allocated. 462 */ 463 if (flags & (CFLGS_OBJFREELIST_SLAB | CFLGS_OFF_SLAB)) { 464 num = slab_size / buffer_size; 465 *left_over = slab_size % buffer_size; 466 } else { 467 num = slab_size / (buffer_size + sizeof(freelist_idx_t)); 468 *left_over = slab_size % 469 (buffer_size + sizeof(freelist_idx_t)); 470 } 471 472 return num; 473 } 474 475 #if DEBUG 476 #define slab_error(cachep, msg) __slab_error(__func__, cachep, msg) 477 478 static void __slab_error(const char *function, struct kmem_cache *cachep, 479 char *msg) 480 { 481 pr_err("slab error in %s(): cache `%s': %s\n", 482 function, cachep->name, msg); 483 dump_stack(); 484 add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE); 485 } 486 #endif 487 488 /* 489 * By default on NUMA we use alien caches to stage the freeing of 490 * objects allocated from other nodes. This causes massive memory 491 * inefficiencies when using fake NUMA setup to split memory into a 492 * large number of small nodes, so it can be disabled on the command 493 * line 494 */ 495 496 static int use_alien_caches __read_mostly = 1; 497 static int __init noaliencache_setup(char *s) 498 { 499 use_alien_caches = 0; 500 return 1; 501 } 502 __setup("noaliencache", noaliencache_setup); 503 504 static int __init slab_max_order_setup(char *str) 505 { 506 get_option(&str, &slab_max_order); 507 slab_max_order = slab_max_order < 0 ? 0 : 508 min(slab_max_order, MAX_ORDER - 1); 509 slab_max_order_set = true; 510 511 return 1; 512 } 513 __setup("slab_max_order=", slab_max_order_setup); 514 515 #ifdef CONFIG_NUMA 516 /* 517 * Special reaping functions for NUMA systems called from cache_reap(). 518 * These take care of doing round robin flushing of alien caches (containing 519 * objects freed on different nodes from which they were allocated) and the 520 * flushing of remote pcps by calling drain_node_pages. 521 */ 522 static DEFINE_PER_CPU(unsigned long, slab_reap_node); 523 524 static void init_reap_node(int cpu) 525 { 526 per_cpu(slab_reap_node, cpu) = next_node_in(cpu_to_mem(cpu), 527 node_online_map); 528 } 529 530 static void next_reap_node(void) 531 { 532 int node = __this_cpu_read(slab_reap_node); 533 534 node = next_node_in(node, node_online_map); 535 __this_cpu_write(slab_reap_node, node); 536 } 537 538 #else 539 #define init_reap_node(cpu) do { } while (0) 540 #define next_reap_node(void) do { } while (0) 541 #endif 542 543 /* 544 * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz 545 * via the workqueue/eventd. 546 * Add the CPU number into the expiration time to minimize the possibility of 547 * the CPUs getting into lockstep and contending for the global cache chain 548 * lock. 549 */ 550 static void start_cpu_timer(int cpu) 551 { 552 struct delayed_work *reap_work = &per_cpu(slab_reap_work, cpu); 553 554 /* 555 * When this gets called from do_initcalls via cpucache_init(), 556 * init_workqueues() has already run, so keventd will be setup 557 * at that time. 558 */ 559 if (keventd_up() && reap_work->work.func == NULL) { 560 init_reap_node(cpu); 561 INIT_DEFERRABLE_WORK(reap_work, cache_reap); 562 schedule_delayed_work_on(cpu, reap_work, 563 __round_jiffies_relative(HZ, cpu)); 564 } 565 } 566 567 static void init_arraycache(struct array_cache *ac, int limit, int batch) 568 { 569 /* 570 * The array_cache structures contain pointers to free object. 571 * However, when such objects are allocated or transferred to another 572 * cache the pointers are not cleared and they could be counted as 573 * valid references during a kmemleak scan. Therefore, kmemleak must 574 * not scan such objects. 575 */ 576 kmemleak_no_scan(ac); 577 if (ac) { 578 ac->avail = 0; 579 ac->limit = limit; 580 ac->batchcount = batch; 581 ac->touched = 0; 582 } 583 } 584 585 static struct array_cache *alloc_arraycache(int node, int entries, 586 int batchcount, gfp_t gfp) 587 { 588 size_t memsize = sizeof(void *) * entries + sizeof(struct array_cache); 589 struct array_cache *ac = NULL; 590 591 ac = kmalloc_node(memsize, gfp, node); 592 init_arraycache(ac, entries, batchcount); 593 return ac; 594 } 595 596 static noinline void cache_free_pfmemalloc(struct kmem_cache *cachep, 597 struct page *page, void *objp) 598 { 599 struct kmem_cache_node *n; 600 int page_node; 601 LIST_HEAD(list); 602 603 page_node = page_to_nid(page); 604 n = get_node(cachep, page_node); 605 606 spin_lock(&n->list_lock); 607 free_block(cachep, &objp, 1, page_node, &list); 608 spin_unlock(&n->list_lock); 609 610 slabs_destroy(cachep, &list); 611 } 612 613 /* 614 * Transfer objects in one arraycache to another. 615 * Locking must be handled by the caller. 616 * 617 * Return the number of entries transferred. 618 */ 619 static int transfer_objects(struct array_cache *to, 620 struct array_cache *from, unsigned int max) 621 { 622 /* Figure out how many entries to transfer */ 623 int nr = min3(from->avail, max, to->limit - to->avail); 624 625 if (!nr) 626 return 0; 627 628 memcpy(to->entry + to->avail, from->entry + from->avail -nr, 629 sizeof(void *) *nr); 630 631 from->avail -= nr; 632 to->avail += nr; 633 return nr; 634 } 635 636 #ifndef CONFIG_NUMA 637 638 #define drain_alien_cache(cachep, alien) do { } while (0) 639 #define reap_alien(cachep, n) do { } while (0) 640 641 static inline struct alien_cache **alloc_alien_cache(int node, 642 int limit, gfp_t gfp) 643 { 644 return NULL; 645 } 646 647 static inline void free_alien_cache(struct alien_cache **ac_ptr) 648 { 649 } 650 651 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 652 { 653 return 0; 654 } 655 656 static inline void *alternate_node_alloc(struct kmem_cache *cachep, 657 gfp_t flags) 658 { 659 return NULL; 660 } 661 662 static inline void *____cache_alloc_node(struct kmem_cache *cachep, 663 gfp_t flags, int nodeid) 664 { 665 return NULL; 666 } 667 668 static inline gfp_t gfp_exact_node(gfp_t flags) 669 { 670 return flags & ~__GFP_NOFAIL; 671 } 672 673 #else /* CONFIG_NUMA */ 674 675 static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int); 676 static void *alternate_node_alloc(struct kmem_cache *, gfp_t); 677 678 static struct alien_cache *__alloc_alien_cache(int node, int entries, 679 int batch, gfp_t gfp) 680 { 681 size_t memsize = sizeof(void *) * entries + sizeof(struct alien_cache); 682 struct alien_cache *alc = NULL; 683 684 alc = kmalloc_node(memsize, gfp, node); 685 init_arraycache(&alc->ac, entries, batch); 686 spin_lock_init(&alc->lock); 687 return alc; 688 } 689 690 static struct alien_cache **alloc_alien_cache(int node, int limit, gfp_t gfp) 691 { 692 struct alien_cache **alc_ptr; 693 size_t memsize = sizeof(void *) * nr_node_ids; 694 int i; 695 696 if (limit > 1) 697 limit = 12; 698 alc_ptr = kzalloc_node(memsize, gfp, node); 699 if (!alc_ptr) 700 return NULL; 701 702 for_each_node(i) { 703 if (i == node || !node_online(i)) 704 continue; 705 alc_ptr[i] = __alloc_alien_cache(node, limit, 0xbaadf00d, gfp); 706 if (!alc_ptr[i]) { 707 for (i--; i >= 0; i--) 708 kfree(alc_ptr[i]); 709 kfree(alc_ptr); 710 return NULL; 711 } 712 } 713 return alc_ptr; 714 } 715 716 static void free_alien_cache(struct alien_cache **alc_ptr) 717 { 718 int i; 719 720 if (!alc_ptr) 721 return; 722 for_each_node(i) 723 kfree(alc_ptr[i]); 724 kfree(alc_ptr); 725 } 726 727 static void __drain_alien_cache(struct kmem_cache *cachep, 728 struct array_cache *ac, int node, 729 struct list_head *list) 730 { 731 struct kmem_cache_node *n = get_node(cachep, node); 732 733 if (ac->avail) { 734 spin_lock(&n->list_lock); 735 /* 736 * Stuff objects into the remote nodes shared array first. 737 * That way we could avoid the overhead of putting the objects 738 * into the free lists and getting them back later. 739 */ 740 if (n->shared) 741 transfer_objects(n->shared, ac, ac->limit); 742 743 free_block(cachep, ac->entry, ac->avail, node, list); 744 ac->avail = 0; 745 spin_unlock(&n->list_lock); 746 } 747 } 748 749 /* 750 * Called from cache_reap() to regularly drain alien caches round robin. 751 */ 752 static void reap_alien(struct kmem_cache *cachep, struct kmem_cache_node *n) 753 { 754 int node = __this_cpu_read(slab_reap_node); 755 756 if (n->alien) { 757 struct alien_cache *alc = n->alien[node]; 758 struct array_cache *ac; 759 760 if (alc) { 761 ac = &alc->ac; 762 if (ac->avail && spin_trylock_irq(&alc->lock)) { 763 LIST_HEAD(list); 764 765 __drain_alien_cache(cachep, ac, node, &list); 766 spin_unlock_irq(&alc->lock); 767 slabs_destroy(cachep, &list); 768 } 769 } 770 } 771 } 772 773 static void drain_alien_cache(struct kmem_cache *cachep, 774 struct alien_cache **alien) 775 { 776 int i = 0; 777 struct alien_cache *alc; 778 struct array_cache *ac; 779 unsigned long flags; 780 781 for_each_online_node(i) { 782 alc = alien[i]; 783 if (alc) { 784 LIST_HEAD(list); 785 786 ac = &alc->ac; 787 spin_lock_irqsave(&alc->lock, flags); 788 __drain_alien_cache(cachep, ac, i, &list); 789 spin_unlock_irqrestore(&alc->lock, flags); 790 slabs_destroy(cachep, &list); 791 } 792 } 793 } 794 795 static int __cache_free_alien(struct kmem_cache *cachep, void *objp, 796 int node, int page_node) 797 { 798 struct kmem_cache_node *n; 799 struct alien_cache *alien = NULL; 800 struct array_cache *ac; 801 LIST_HEAD(list); 802 803 n = get_node(cachep, node); 804 STATS_INC_NODEFREES(cachep); 805 if (n->alien && n->alien[page_node]) { 806 alien = n->alien[page_node]; 807 ac = &alien->ac; 808 spin_lock(&alien->lock); 809 if (unlikely(ac->avail == ac->limit)) { 810 STATS_INC_ACOVERFLOW(cachep); 811 __drain_alien_cache(cachep, ac, page_node, &list); 812 } 813 ac->entry[ac->avail++] = objp; 814 spin_unlock(&alien->lock); 815 slabs_destroy(cachep, &list); 816 } else { 817 n = get_node(cachep, page_node); 818 spin_lock(&n->list_lock); 819 free_block(cachep, &objp, 1, page_node, &list); 820 spin_unlock(&n->list_lock); 821 slabs_destroy(cachep, &list); 822 } 823 return 1; 824 } 825 826 static inline int cache_free_alien(struct kmem_cache *cachep, void *objp) 827 { 828 int page_node = page_to_nid(virt_to_page(objp)); 829 int node = numa_mem_id(); 830 /* 831 * Make sure we are not freeing a object from another node to the array 832 * cache on this cpu. 833 */ 834 if (likely(node == page_node)) 835 return 0; 836 837 return __cache_free_alien(cachep, objp, node, page_node); 838 } 839 840 /* 841 * Construct gfp mask to allocate from a specific node but do not reclaim or 842 * warn about failures. 843 */ 844 static inline gfp_t gfp_exact_node(gfp_t flags) 845 { 846 return (flags | __GFP_THISNODE | __GFP_NOWARN) & ~(__GFP_RECLAIM|__GFP_NOFAIL); 847 } 848 #endif 849 850 static int init_cache_node(struct kmem_cache *cachep, int node, gfp_t gfp) 851 { 852 struct kmem_cache_node *n; 853 854 /* 855 * Set up the kmem_cache_node for cpu before we can 856 * begin anything. Make sure some other cpu on this 857 * node has not already allocated this 858 */ 859 n = get_node(cachep, node); 860 if (n) { 861 spin_lock_irq(&n->list_lock); 862 n->free_limit = (1 + nr_cpus_node(node)) * cachep->batchcount + 863 cachep->num; 864 spin_unlock_irq(&n->list_lock); 865 866 return 0; 867 } 868 869 n = kmalloc_node(sizeof(struct kmem_cache_node), gfp, node); 870 if (!n) 871 return -ENOMEM; 872 873 kmem_cache_node_init(n); 874 n->next_reap = jiffies + REAPTIMEOUT_NODE + 875 ((unsigned long)cachep) % REAPTIMEOUT_NODE; 876 877 n->free_limit = 878 (1 + nr_cpus_node(node)) * cachep->batchcount + cachep->num; 879 880 /* 881 * The kmem_cache_nodes don't come and go as CPUs 882 * come and go. slab_mutex is sufficient 883 * protection here. 884 */ 885 cachep->node[node] = n; 886 887 return 0; 888 } 889 890 #if (defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)) || defined(CONFIG_SMP) 891 /* 892 * Allocates and initializes node for a node on each slab cache, used for 893 * either memory or cpu hotplug. If memory is being hot-added, the kmem_cache_node 894 * will be allocated off-node since memory is not yet online for the new node. 895 * When hotplugging memory or a cpu, existing node are not replaced if 896 * already in use. 897 * 898 * Must hold slab_mutex. 899 */ 900 static int init_cache_node_node(int node) 901 { 902 int ret; 903 struct kmem_cache *cachep; 904 905 list_for_each_entry(cachep, &slab_caches, list) { 906 ret = init_cache_node(cachep, node, GFP_KERNEL); 907 if (ret) 908 return ret; 909 } 910 911 return 0; 912 } 913 #endif 914 915 static int setup_kmem_cache_node(struct kmem_cache *cachep, 916 int node, gfp_t gfp, bool force_change) 917 { 918 int ret = -ENOMEM; 919 struct kmem_cache_node *n; 920 struct array_cache *old_shared = NULL; 921 struct array_cache *new_shared = NULL; 922 struct alien_cache **new_alien = NULL; 923 LIST_HEAD(list); 924 925 if (use_alien_caches) { 926 new_alien = alloc_alien_cache(node, cachep->limit, gfp); 927 if (!new_alien) 928 goto fail; 929 } 930 931 if (cachep->shared) { 932 new_shared = alloc_arraycache(node, 933 cachep->shared * cachep->batchcount, 0xbaadf00d, gfp); 934 if (!new_shared) 935 goto fail; 936 } 937 938 ret = init_cache_node(cachep, node, gfp); 939 if (ret) 940 goto fail; 941 942 n = get_node(cachep, node); 943 spin_lock_irq(&n->list_lock); 944 if (n->shared && force_change) { 945 free_block(cachep, n->shared->entry, 946 n->shared->avail, node, &list); 947 n->shared->avail = 0; 948 } 949 950 if (!n->shared || force_change) { 951 old_shared = n->shared; 952 n->shared = new_shared; 953 new_shared = NULL; 954 } 955 956 if (!n->alien) { 957 n->alien = new_alien; 958 new_alien = NULL; 959 } 960 961 spin_unlock_irq(&n->list_lock); 962 slabs_destroy(cachep, &list); 963 964 /* 965 * To protect lockless access to n->shared during irq disabled context. 966 * If n->shared isn't NULL in irq disabled context, accessing to it is 967 * guaranteed to be valid until irq is re-enabled, because it will be 968 * freed after synchronize_sched(). 969 */ 970 if (old_shared && force_change) 971 synchronize_sched(); 972 973 fail: 974 kfree(old_shared); 975 kfree(new_shared); 976 free_alien_cache(new_alien); 977 978 return ret; 979 } 980 981 #ifdef CONFIG_SMP 982 983 static void cpuup_canceled(long cpu) 984 { 985 struct kmem_cache *cachep; 986 struct kmem_cache_node *n = NULL; 987 int node = cpu_to_mem(cpu); 988 const struct cpumask *mask = cpumask_of_node(node); 989 990 list_for_each_entry(cachep, &slab_caches, list) { 991 struct array_cache *nc; 992 struct array_cache *shared; 993 struct alien_cache **alien; 994 LIST_HEAD(list); 995 996 n = get_node(cachep, node); 997 if (!n) 998 continue; 999 1000 spin_lock_irq(&n->list_lock); 1001 1002 /* Free limit for this kmem_cache_node */ 1003 n->free_limit -= cachep->batchcount; 1004 1005 /* cpu is dead; no one can alloc from it. */ 1006 nc = per_cpu_ptr(cachep->cpu_cache, cpu); 1007 if (nc) { 1008 free_block(cachep, nc->entry, nc->avail, node, &list); 1009 nc->avail = 0; 1010 } 1011 1012 if (!cpumask_empty(mask)) { 1013 spin_unlock_irq(&n->list_lock); 1014 goto free_slab; 1015 } 1016 1017 shared = n->shared; 1018 if (shared) { 1019 free_block(cachep, shared->entry, 1020 shared->avail, node, &list); 1021 n->shared = NULL; 1022 } 1023 1024 alien = n->alien; 1025 n->alien = NULL; 1026 1027 spin_unlock_irq(&n->list_lock); 1028 1029 kfree(shared); 1030 if (alien) { 1031 drain_alien_cache(cachep, alien); 1032 free_alien_cache(alien); 1033 } 1034 1035 free_slab: 1036 slabs_destroy(cachep, &list); 1037 } 1038 /* 1039 * In the previous loop, all the objects were freed to 1040 * the respective cache's slabs, now we can go ahead and 1041 * shrink each nodelist to its limit. 1042 */ 1043 list_for_each_entry(cachep, &slab_caches, list) { 1044 n = get_node(cachep, node); 1045 if (!n) 1046 continue; 1047 drain_freelist(cachep, n, INT_MAX); 1048 } 1049 } 1050 1051 static int cpuup_prepare(long cpu) 1052 { 1053 struct kmem_cache *cachep; 1054 int node = cpu_to_mem(cpu); 1055 int err; 1056 1057 /* 1058 * We need to do this right in the beginning since 1059 * alloc_arraycache's are going to use this list. 1060 * kmalloc_node allows us to add the slab to the right 1061 * kmem_cache_node and not this cpu's kmem_cache_node 1062 */ 1063 err = init_cache_node_node(node); 1064 if (err < 0) 1065 goto bad; 1066 1067 /* 1068 * Now we can go ahead with allocating the shared arrays and 1069 * array caches 1070 */ 1071 list_for_each_entry(cachep, &slab_caches, list) { 1072 err = setup_kmem_cache_node(cachep, node, GFP_KERNEL, false); 1073 if (err) 1074 goto bad; 1075 } 1076 1077 return 0; 1078 bad: 1079 cpuup_canceled(cpu); 1080 return -ENOMEM; 1081 } 1082 1083 int slab_prepare_cpu(unsigned int cpu) 1084 { 1085 int err; 1086 1087 mutex_lock(&slab_mutex); 1088 err = cpuup_prepare(cpu); 1089 mutex_unlock(&slab_mutex); 1090 return err; 1091 } 1092 1093 /* 1094 * This is called for a failed online attempt and for a successful 1095 * offline. 1096 * 1097 * Even if all the cpus of a node are down, we don't free the 1098 * kmem_list3 of any cache. This to avoid a race between cpu_down, and 1099 * a kmalloc allocation from another cpu for memory from the node of 1100 * the cpu going down. The list3 structure is usually allocated from 1101 * kmem_cache_create() and gets destroyed at kmem_cache_destroy(). 1102 */ 1103 int slab_dead_cpu(unsigned int cpu) 1104 { 1105 mutex_lock(&slab_mutex); 1106 cpuup_canceled(cpu); 1107 mutex_unlock(&slab_mutex); 1108 return 0; 1109 } 1110 #endif 1111 1112 static int slab_online_cpu(unsigned int cpu) 1113 { 1114 start_cpu_timer(cpu); 1115 return 0; 1116 } 1117 1118 static int slab_offline_cpu(unsigned int cpu) 1119 { 1120 /* 1121 * Shutdown cache reaper. Note that the slab_mutex is held so 1122 * that if cache_reap() is invoked it cannot do anything 1123 * expensive but will only modify reap_work and reschedule the 1124 * timer. 1125 */ 1126 cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu)); 1127 /* Now the cache_reaper is guaranteed to be not running. */ 1128 per_cpu(slab_reap_work, cpu).work.func = NULL; 1129 return 0; 1130 } 1131 1132 #if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG) 1133 /* 1134 * Drains freelist for a node on each slab cache, used for memory hot-remove. 1135 * Returns -EBUSY if all objects cannot be drained so that the node is not 1136 * removed. 1137 * 1138 * Must hold slab_mutex. 1139 */ 1140 static int __meminit drain_cache_node_node(int node) 1141 { 1142 struct kmem_cache *cachep; 1143 int ret = 0; 1144 1145 list_for_each_entry(cachep, &slab_caches, list) { 1146 struct kmem_cache_node *n; 1147 1148 n = get_node(cachep, node); 1149 if (!n) 1150 continue; 1151 1152 drain_freelist(cachep, n, INT_MAX); 1153 1154 if (!list_empty(&n->slabs_full) || 1155 !list_empty(&n->slabs_partial)) { 1156 ret = -EBUSY; 1157 break; 1158 } 1159 } 1160 return ret; 1161 } 1162 1163 static int __meminit slab_memory_callback(struct notifier_block *self, 1164 unsigned long action, void *arg) 1165 { 1166 struct memory_notify *mnb = arg; 1167 int ret = 0; 1168 int nid; 1169 1170 nid = mnb->status_change_nid; 1171 if (nid < 0) 1172 goto out; 1173 1174 switch (action) { 1175 case MEM_GOING_ONLINE: 1176 mutex_lock(&slab_mutex); 1177 ret = init_cache_node_node(nid); 1178 mutex_unlock(&slab_mutex); 1179 break; 1180 case MEM_GOING_OFFLINE: 1181 mutex_lock(&slab_mutex); 1182 ret = drain_cache_node_node(nid); 1183 mutex_unlock(&slab_mutex); 1184 break; 1185 case MEM_ONLINE: 1186 case MEM_OFFLINE: 1187 case MEM_CANCEL_ONLINE: 1188 case MEM_CANCEL_OFFLINE: 1189 break; 1190 } 1191 out: 1192 return notifier_from_errno(ret); 1193 } 1194 #endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */ 1195 1196 /* 1197 * swap the static kmem_cache_node with kmalloced memory 1198 */ 1199 static void __init init_list(struct kmem_cache *cachep, struct kmem_cache_node *list, 1200 int nodeid) 1201 { 1202 struct kmem_cache_node *ptr; 1203 1204 ptr = kmalloc_node(sizeof(struct kmem_cache_node), GFP_NOWAIT, nodeid); 1205 BUG_ON(!ptr); 1206 1207 memcpy(ptr, list, sizeof(struct kmem_cache_node)); 1208 /* 1209 * Do not assume that spinlocks can be initialized via memcpy: 1210 */ 1211 spin_lock_init(&ptr->list_lock); 1212 1213 MAKE_ALL_LISTS(cachep, ptr, nodeid); 1214 cachep->node[nodeid] = ptr; 1215 } 1216 1217 /* 1218 * For setting up all the kmem_cache_node for cache whose buffer_size is same as 1219 * size of kmem_cache_node. 1220 */ 1221 static void __init set_up_node(struct kmem_cache *cachep, int index) 1222 { 1223 int node; 1224 1225 for_each_online_node(node) { 1226 cachep->node[node] = &init_kmem_cache_node[index + node]; 1227 cachep->node[node]->next_reap = jiffies + 1228 REAPTIMEOUT_NODE + 1229 ((unsigned long)cachep) % REAPTIMEOUT_NODE; 1230 } 1231 } 1232 1233 /* 1234 * Initialisation. Called after the page allocator have been initialised and 1235 * before smp_init(). 1236 */ 1237 void __init kmem_cache_init(void) 1238 { 1239 int i; 1240 1241 BUILD_BUG_ON(sizeof(((struct page *)NULL)->lru) < 1242 sizeof(struct rcu_head)); 1243 kmem_cache = &kmem_cache_boot; 1244 1245 if (!IS_ENABLED(CONFIG_NUMA) || num_possible_nodes() == 1) 1246 use_alien_caches = 0; 1247 1248 for (i = 0; i < NUM_INIT_LISTS; i++) 1249 kmem_cache_node_init(&init_kmem_cache_node[i]); 1250 1251 /* 1252 * Fragmentation resistance on low memory - only use bigger 1253 * page orders on machines with more than 32MB of memory if 1254 * not overridden on the command line. 1255 */ 1256 if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT) 1257 slab_max_order = SLAB_MAX_ORDER_HI; 1258 1259 /* Bootstrap is tricky, because several objects are allocated 1260 * from caches that do not exist yet: 1261 * 1) initialize the kmem_cache cache: it contains the struct 1262 * kmem_cache structures of all caches, except kmem_cache itself: 1263 * kmem_cache is statically allocated. 1264 * Initially an __init data area is used for the head array and the 1265 * kmem_cache_node structures, it's replaced with a kmalloc allocated 1266 * array at the end of the bootstrap. 1267 * 2) Create the first kmalloc cache. 1268 * The struct kmem_cache for the new cache is allocated normally. 1269 * An __init data area is used for the head array. 1270 * 3) Create the remaining kmalloc caches, with minimally sized 1271 * head arrays. 1272 * 4) Replace the __init data head arrays for kmem_cache and the first 1273 * kmalloc cache with kmalloc allocated arrays. 1274 * 5) Replace the __init data for kmem_cache_node for kmem_cache and 1275 * the other cache's with kmalloc allocated memory. 1276 * 6) Resize the head arrays of the kmalloc caches to their final sizes. 1277 */ 1278 1279 /* 1) create the kmem_cache */ 1280 1281 /* 1282 * struct kmem_cache size depends on nr_node_ids & nr_cpu_ids 1283 */ 1284 create_boot_cache(kmem_cache, "kmem_cache", 1285 offsetof(struct kmem_cache, node) + 1286 nr_node_ids * sizeof(struct kmem_cache_node *), 1287 SLAB_HWCACHE_ALIGN); 1288 list_add(&kmem_cache->list, &slab_caches); 1289 slab_state = PARTIAL; 1290 1291 /* 1292 * Initialize the caches that provide memory for the kmem_cache_node 1293 * structures first. Without this, further allocations will bug. 1294 */ 1295 kmalloc_caches[INDEX_NODE] = create_kmalloc_cache("kmalloc-node", 1296 kmalloc_size(INDEX_NODE), ARCH_KMALLOC_FLAGS); 1297 slab_state = PARTIAL_NODE; 1298 setup_kmalloc_cache_index_table(); 1299 1300 slab_early_init = 0; 1301 1302 /* 5) Replace the bootstrap kmem_cache_node */ 1303 { 1304 int nid; 1305 1306 for_each_online_node(nid) { 1307 init_list(kmem_cache, &init_kmem_cache_node[CACHE_CACHE + nid], nid); 1308 1309 init_list(kmalloc_caches[INDEX_NODE], 1310 &init_kmem_cache_node[SIZE_NODE + nid], nid); 1311 } 1312 } 1313 1314 create_kmalloc_caches(ARCH_KMALLOC_FLAGS); 1315 } 1316 1317 void __init kmem_cache_init_late(void) 1318 { 1319 struct kmem_cache *cachep; 1320 1321 slab_state = UP; 1322 1323 /* 6) resize the head arrays to their final sizes */ 1324 mutex_lock(&slab_mutex); 1325 list_for_each_entry(cachep, &slab_caches, list) 1326 if (enable_cpucache(cachep, GFP_NOWAIT)) 1327 BUG(); 1328 mutex_unlock(&slab_mutex); 1329 1330 /* Done! */ 1331 slab_state = FULL; 1332 1333 #ifdef CONFIG_NUMA 1334 /* 1335 * Register a memory hotplug callback that initializes and frees 1336 * node. 1337 */ 1338 hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); 1339 #endif 1340 1341 /* 1342 * The reap timers are started later, with a module init call: That part 1343 * of the kernel is not yet operational. 1344 */ 1345 } 1346 1347 static int __init cpucache_init(void) 1348 { 1349 int ret; 1350 1351 /* 1352 * Register the timers that return unneeded pages to the page allocator 1353 */ 1354 ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "SLAB online", 1355 slab_online_cpu, slab_offline_cpu); 1356 WARN_ON(ret < 0); 1357 1358 /* Done! */ 1359 slab_state = FULL; 1360 return 0; 1361 } 1362 __initcall(cpucache_init); 1363 1364 static noinline void 1365 slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid) 1366 { 1367 #if DEBUG 1368 struct kmem_cache_node *n; 1369 struct page *page; 1370 unsigned long flags; 1371 int node; 1372 static DEFINE_RATELIMIT_STATE(slab_oom_rs, DEFAULT_RATELIMIT_INTERVAL, 1373 DEFAULT_RATELIMIT_BURST); 1374 1375 if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slab_oom_rs)) 1376 return; 1377 1378 pr_warn("SLAB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n", 1379 nodeid, gfpflags, &gfpflags); 1380 pr_warn(" cache: %s, object size: %d, order: %d\n", 1381 cachep->name, cachep->size, cachep->gfporder); 1382 1383 for_each_kmem_cache_node(cachep, node, n) { 1384 unsigned long active_objs = 0, num_objs = 0, free_objects = 0; 1385 unsigned long active_slabs = 0, num_slabs = 0; 1386 unsigned long num_slabs_partial = 0, num_slabs_free = 0; 1387 unsigned long num_slabs_full; 1388 1389 spin_lock_irqsave(&n->list_lock, flags); 1390 num_slabs = n->num_slabs; 1391 list_for_each_entry(page, &n->slabs_partial, lru) { 1392 active_objs += page->active; 1393 num_slabs_partial++; 1394 } 1395 list_for_each_entry(page, &n->slabs_free, lru) 1396 num_slabs_free++; 1397 1398 free_objects += n->free_objects; 1399 spin_unlock_irqrestore(&n->list_lock, flags); 1400 1401 num_objs = num_slabs * cachep->num; 1402 active_slabs = num_slabs - num_slabs_free; 1403 num_slabs_full = num_slabs - 1404 (num_slabs_partial + num_slabs_free); 1405 active_objs += (num_slabs_full * cachep->num); 1406 1407 pr_warn(" node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n", 1408 node, active_slabs, num_slabs, active_objs, num_objs, 1409 free_objects); 1410 } 1411 #endif 1412 } 1413 1414 /* 1415 * Interface to system's page allocator. No need to hold the 1416 * kmem_cache_node ->list_lock. 1417 * 1418 * If we requested dmaable memory, we will get it. Even if we 1419 * did not request dmaable memory, we might get it, but that 1420 * would be relatively rare and ignorable. 1421 */ 1422 static struct page *kmem_getpages(struct kmem_cache *cachep, gfp_t flags, 1423 int nodeid) 1424 { 1425 struct page *page; 1426 int nr_pages; 1427 1428 flags |= cachep->allocflags; 1429 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1430 flags |= __GFP_RECLAIMABLE; 1431 1432 page = __alloc_pages_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder); 1433 if (!page) { 1434 slab_out_of_memory(cachep, flags, nodeid); 1435 return NULL; 1436 } 1437 1438 if (memcg_charge_slab(page, flags, cachep->gfporder, cachep)) { 1439 __free_pages(page, cachep->gfporder); 1440 return NULL; 1441 } 1442 1443 nr_pages = (1 << cachep->gfporder); 1444 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1445 add_zone_page_state(page_zone(page), 1446 NR_SLAB_RECLAIMABLE, nr_pages); 1447 else 1448 add_zone_page_state(page_zone(page), 1449 NR_SLAB_UNRECLAIMABLE, nr_pages); 1450 1451 __SetPageSlab(page); 1452 /* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */ 1453 if (sk_memalloc_socks() && page_is_pfmemalloc(page)) 1454 SetPageSlabPfmemalloc(page); 1455 1456 if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) { 1457 kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid); 1458 1459 if (cachep->ctor) 1460 kmemcheck_mark_uninitialized_pages(page, nr_pages); 1461 else 1462 kmemcheck_mark_unallocated_pages(page, nr_pages); 1463 } 1464 1465 return page; 1466 } 1467 1468 /* 1469 * Interface to system's page release. 1470 */ 1471 static void kmem_freepages(struct kmem_cache *cachep, struct page *page) 1472 { 1473 int order = cachep->gfporder; 1474 unsigned long nr_freed = (1 << order); 1475 1476 kmemcheck_free_shadow(page, order); 1477 1478 if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 1479 sub_zone_page_state(page_zone(page), 1480 NR_SLAB_RECLAIMABLE, nr_freed); 1481 else 1482 sub_zone_page_state(page_zone(page), 1483 NR_SLAB_UNRECLAIMABLE, nr_freed); 1484 1485 BUG_ON(!PageSlab(page)); 1486 __ClearPageSlabPfmemalloc(page); 1487 __ClearPageSlab(page); 1488 page_mapcount_reset(page); 1489 page->mapping = NULL; 1490 1491 if (current->reclaim_state) 1492 current->reclaim_state->reclaimed_slab += nr_freed; 1493 memcg_uncharge_slab(page, order, cachep); 1494 __free_pages(page, order); 1495 } 1496 1497 static void kmem_rcu_free(struct rcu_head *head) 1498 { 1499 struct kmem_cache *cachep; 1500 struct page *page; 1501 1502 page = container_of(head, struct page, rcu_head); 1503 cachep = page->slab_cache; 1504 1505 kmem_freepages(cachep, page); 1506 } 1507 1508 #if DEBUG 1509 static bool is_debug_pagealloc_cache(struct kmem_cache *cachep) 1510 { 1511 if (debug_pagealloc_enabled() && OFF_SLAB(cachep) && 1512 (cachep->size % PAGE_SIZE) == 0) 1513 return true; 1514 1515 return false; 1516 } 1517 1518 #ifdef CONFIG_DEBUG_PAGEALLOC 1519 static void store_stackinfo(struct kmem_cache *cachep, unsigned long *addr, 1520 unsigned long caller) 1521 { 1522 int size = cachep->object_size; 1523 1524 addr = (unsigned long *)&((char *)addr)[obj_offset(cachep)]; 1525 1526 if (size < 5 * sizeof(unsigned long)) 1527 return; 1528 1529 *addr++ = 0x12345678; 1530 *addr++ = caller; 1531 *addr++ = smp_processor_id(); 1532 size -= 3 * sizeof(unsigned long); 1533 { 1534 unsigned long *sptr = &caller; 1535 unsigned long svalue; 1536 1537 while (!kstack_end(sptr)) { 1538 svalue = *sptr++; 1539 if (kernel_text_address(svalue)) { 1540 *addr++ = svalue; 1541 size -= sizeof(unsigned long); 1542 if (size <= sizeof(unsigned long)) 1543 break; 1544 } 1545 } 1546 1547 } 1548 *addr++ = 0x87654321; 1549 } 1550 1551 static void slab_kernel_map(struct kmem_cache *cachep, void *objp, 1552 int map, unsigned long caller) 1553 { 1554 if (!is_debug_pagealloc_cache(cachep)) 1555 return; 1556 1557 if (caller) 1558 store_stackinfo(cachep, objp, caller); 1559 1560 kernel_map_pages(virt_to_page(objp), cachep->size / PAGE_SIZE, map); 1561 } 1562 1563 #else 1564 static inline void slab_kernel_map(struct kmem_cache *cachep, void *objp, 1565 int map, unsigned long caller) {} 1566 1567 #endif 1568 1569 static void poison_obj(struct kmem_cache *cachep, void *addr, unsigned char val) 1570 { 1571 int size = cachep->object_size; 1572 addr = &((char *)addr)[obj_offset(cachep)]; 1573 1574 memset(addr, val, size); 1575 *(unsigned char *)(addr + size - 1) = POISON_END; 1576 } 1577 1578 static void dump_line(char *data, int offset, int limit) 1579 { 1580 int i; 1581 unsigned char error = 0; 1582 int bad_count = 0; 1583 1584 pr_err("%03x: ", offset); 1585 for (i = 0; i < limit; i++) { 1586 if (data[offset + i] != POISON_FREE) { 1587 error = data[offset + i]; 1588 bad_count++; 1589 } 1590 } 1591 print_hex_dump(KERN_CONT, "", 0, 16, 1, 1592 &data[offset], limit, 1); 1593 1594 if (bad_count == 1) { 1595 error ^= POISON_FREE; 1596 if (!(error & (error - 1))) { 1597 pr_err("Single bit error detected. Probably bad RAM.\n"); 1598 #ifdef CONFIG_X86 1599 pr_err("Run memtest86+ or a similar memory test tool.\n"); 1600 #else 1601 pr_err("Run a memory test tool.\n"); 1602 #endif 1603 } 1604 } 1605 } 1606 #endif 1607 1608 #if DEBUG 1609 1610 static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines) 1611 { 1612 int i, size; 1613 char *realobj; 1614 1615 if (cachep->flags & SLAB_RED_ZONE) { 1616 pr_err("Redzone: 0x%llx/0x%llx\n", 1617 *dbg_redzone1(cachep, objp), 1618 *dbg_redzone2(cachep, objp)); 1619 } 1620 1621 if (cachep->flags & SLAB_STORE_USER) { 1622 pr_err("Last user: [<%p>](%pSR)\n", 1623 *dbg_userword(cachep, objp), 1624 *dbg_userword(cachep, objp)); 1625 } 1626 realobj = (char *)objp + obj_offset(cachep); 1627 size = cachep->object_size; 1628 for (i = 0; i < size && lines; i += 16, lines--) { 1629 int limit; 1630 limit = 16; 1631 if (i + limit > size) 1632 limit = size - i; 1633 dump_line(realobj, i, limit); 1634 } 1635 } 1636 1637 static void check_poison_obj(struct kmem_cache *cachep, void *objp) 1638 { 1639 char *realobj; 1640 int size, i; 1641 int lines = 0; 1642 1643 if (is_debug_pagealloc_cache(cachep)) 1644 return; 1645 1646 realobj = (char *)objp + obj_offset(cachep); 1647 size = cachep->object_size; 1648 1649 for (i = 0; i < size; i++) { 1650 char exp = POISON_FREE; 1651 if (i == size - 1) 1652 exp = POISON_END; 1653 if (realobj[i] != exp) { 1654 int limit; 1655 /* Mismatch ! */ 1656 /* Print header */ 1657 if (lines == 0) { 1658 pr_err("Slab corruption (%s): %s start=%p, len=%d\n", 1659 print_tainted(), cachep->name, 1660 realobj, size); 1661 print_objinfo(cachep, objp, 0); 1662 } 1663 /* Hexdump the affected line */ 1664 i = (i / 16) * 16; 1665 limit = 16; 1666 if (i + limit > size) 1667 limit = size - i; 1668 dump_line(realobj, i, limit); 1669 i += 16; 1670 lines++; 1671 /* Limit to 5 lines */ 1672 if (lines > 5) 1673 break; 1674 } 1675 } 1676 if (lines != 0) { 1677 /* Print some data about the neighboring objects, if they 1678 * exist: 1679 */ 1680 struct page *page = virt_to_head_page(objp); 1681 unsigned int objnr; 1682 1683 objnr = obj_to_index(cachep, page, objp); 1684 if (objnr) { 1685 objp = index_to_obj(cachep, page, objnr - 1); 1686 realobj = (char *)objp + obj_offset(cachep); 1687 pr_err("Prev obj: start=%p, len=%d\n", realobj, size); 1688 print_objinfo(cachep, objp, 2); 1689 } 1690 if (objnr + 1 < cachep->num) { 1691 objp = index_to_obj(cachep, page, objnr + 1); 1692 realobj = (char *)objp + obj_offset(cachep); 1693 pr_err("Next obj: start=%p, len=%d\n", realobj, size); 1694 print_objinfo(cachep, objp, 2); 1695 } 1696 } 1697 } 1698 #endif 1699 1700 #if DEBUG 1701 static void slab_destroy_debugcheck(struct kmem_cache *cachep, 1702 struct page *page) 1703 { 1704 int i; 1705 1706 if (OBJFREELIST_SLAB(cachep) && cachep->flags & SLAB_POISON) { 1707 poison_obj(cachep, page->freelist - obj_offset(cachep), 1708 POISON_FREE); 1709 } 1710 1711 for (i = 0; i < cachep->num; i++) { 1712 void *objp = index_to_obj(cachep, page, i); 1713 1714 if (cachep->flags & SLAB_POISON) { 1715 check_poison_obj(cachep, objp); 1716 slab_kernel_map(cachep, objp, 1, 0); 1717 } 1718 if (cachep->flags & SLAB_RED_ZONE) { 1719 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) 1720 slab_error(cachep, "start of a freed object was overwritten"); 1721 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) 1722 slab_error(cachep, "end of a freed object was overwritten"); 1723 } 1724 } 1725 } 1726 #else 1727 static void slab_destroy_debugcheck(struct kmem_cache *cachep, 1728 struct page *page) 1729 { 1730 } 1731 #endif 1732 1733 /** 1734 * slab_destroy - destroy and release all objects in a slab 1735 * @cachep: cache pointer being destroyed 1736 * @page: page pointer being destroyed 1737 * 1738 * Destroy all the objs in a slab page, and release the mem back to the system. 1739 * Before calling the slab page must have been unlinked from the cache. The 1740 * kmem_cache_node ->list_lock is not held/needed. 1741 */ 1742 static void slab_destroy(struct kmem_cache *cachep, struct page *page) 1743 { 1744 void *freelist; 1745 1746 freelist = page->freelist; 1747 slab_destroy_debugcheck(cachep, page); 1748 if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) 1749 call_rcu(&page->rcu_head, kmem_rcu_free); 1750 else 1751 kmem_freepages(cachep, page); 1752 1753 /* 1754 * From now on, we don't use freelist 1755 * although actual page can be freed in rcu context 1756 */ 1757 if (OFF_SLAB(cachep)) 1758 kmem_cache_free(cachep->freelist_cache, freelist); 1759 } 1760 1761 static void slabs_destroy(struct kmem_cache *cachep, struct list_head *list) 1762 { 1763 struct page *page, *n; 1764 1765 list_for_each_entry_safe(page, n, list, lru) { 1766 list_del(&page->lru); 1767 slab_destroy(cachep, page); 1768 } 1769 } 1770 1771 /** 1772 * calculate_slab_order - calculate size (page order) of slabs 1773 * @cachep: pointer to the cache that is being created 1774 * @size: size of objects to be created in this cache. 1775 * @flags: slab allocation flags 1776 * 1777 * Also calculates the number of objects per slab. 1778 * 1779 * This could be made much more intelligent. For now, try to avoid using 1780 * high order pages for slabs. When the gfp() functions are more friendly 1781 * towards high-order requests, this should be changed. 1782 */ 1783 static size_t calculate_slab_order(struct kmem_cache *cachep, 1784 size_t size, unsigned long flags) 1785 { 1786 size_t left_over = 0; 1787 int gfporder; 1788 1789 for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) { 1790 unsigned int num; 1791 size_t remainder; 1792 1793 num = cache_estimate(gfporder, size, flags, &remainder); 1794 if (!num) 1795 continue; 1796 1797 /* Can't handle number of objects more than SLAB_OBJ_MAX_NUM */ 1798 if (num > SLAB_OBJ_MAX_NUM) 1799 break; 1800 1801 if (flags & CFLGS_OFF_SLAB) { 1802 struct kmem_cache *freelist_cache; 1803 size_t freelist_size; 1804 1805 freelist_size = num * sizeof(freelist_idx_t); 1806 freelist_cache = kmalloc_slab(freelist_size, 0u); 1807 if (!freelist_cache) 1808 continue; 1809 1810 /* 1811 * Needed to avoid possible looping condition 1812 * in cache_grow_begin() 1813 */ 1814 if (OFF_SLAB(freelist_cache)) 1815 continue; 1816 1817 /* check if off slab has enough benefit */ 1818 if (freelist_cache->size > cachep->size / 2) 1819 continue; 1820 } 1821 1822 /* Found something acceptable - save it away */ 1823 cachep->num = num; 1824 cachep->gfporder = gfporder; 1825 left_over = remainder; 1826 1827 /* 1828 * A VFS-reclaimable slab tends to have most allocations 1829 * as GFP_NOFS and we really don't want to have to be allocating 1830 * higher-order pages when we are unable to shrink dcache. 1831 */ 1832 if (flags & SLAB_RECLAIM_ACCOUNT) 1833 break; 1834 1835 /* 1836 * Large number of objects is good, but very large slabs are 1837 * currently bad for the gfp()s. 1838 */ 1839 if (gfporder >= slab_max_order) 1840 break; 1841 1842 /* 1843 * Acceptable internal fragmentation? 1844 */ 1845 if (left_over * 8 <= (PAGE_SIZE << gfporder)) 1846 break; 1847 } 1848 return left_over; 1849 } 1850 1851 static struct array_cache __percpu *alloc_kmem_cache_cpus( 1852 struct kmem_cache *cachep, int entries, int batchcount) 1853 { 1854 int cpu; 1855 size_t size; 1856 struct array_cache __percpu *cpu_cache; 1857 1858 size = sizeof(void *) * entries + sizeof(struct array_cache); 1859 cpu_cache = __alloc_percpu(size, sizeof(void *)); 1860 1861 if (!cpu_cache) 1862 return NULL; 1863 1864 for_each_possible_cpu(cpu) { 1865 init_arraycache(per_cpu_ptr(cpu_cache, cpu), 1866 entries, batchcount); 1867 } 1868 1869 return cpu_cache; 1870 } 1871 1872 static int __ref setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp) 1873 { 1874 if (slab_state >= FULL) 1875 return enable_cpucache(cachep, gfp); 1876 1877 cachep->cpu_cache = alloc_kmem_cache_cpus(cachep, 1, 1); 1878 if (!cachep->cpu_cache) 1879 return 1; 1880 1881 if (slab_state == DOWN) { 1882 /* Creation of first cache (kmem_cache). */ 1883 set_up_node(kmem_cache, CACHE_CACHE); 1884 } else if (slab_state == PARTIAL) { 1885 /* For kmem_cache_node */ 1886 set_up_node(cachep, SIZE_NODE); 1887 } else { 1888 int node; 1889 1890 for_each_online_node(node) { 1891 cachep->node[node] = kmalloc_node( 1892 sizeof(struct kmem_cache_node), gfp, node); 1893 BUG_ON(!cachep->node[node]); 1894 kmem_cache_node_init(cachep->node[node]); 1895 } 1896 } 1897 1898 cachep->node[numa_mem_id()]->next_reap = 1899 jiffies + REAPTIMEOUT_NODE + 1900 ((unsigned long)cachep) % REAPTIMEOUT_NODE; 1901 1902 cpu_cache_get(cachep)->avail = 0; 1903 cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES; 1904 cpu_cache_get(cachep)->batchcount = 1; 1905 cpu_cache_get(cachep)->touched = 0; 1906 cachep->batchcount = 1; 1907 cachep->limit = BOOT_CPUCACHE_ENTRIES; 1908 return 0; 1909 } 1910 1911 unsigned long kmem_cache_flags(unsigned long object_size, 1912 unsigned long flags, const char *name, 1913 void (*ctor)(void *)) 1914 { 1915 return flags; 1916 } 1917 1918 struct kmem_cache * 1919 __kmem_cache_alias(const char *name, size_t size, size_t align, 1920 unsigned long flags, void (*ctor)(void *)) 1921 { 1922 struct kmem_cache *cachep; 1923 1924 cachep = find_mergeable(size, align, flags, name, ctor); 1925 if (cachep) { 1926 cachep->refcount++; 1927 1928 /* 1929 * Adjust the object sizes so that we clear 1930 * the complete object on kzalloc. 1931 */ 1932 cachep->object_size = max_t(int, cachep->object_size, size); 1933 } 1934 return cachep; 1935 } 1936 1937 static bool set_objfreelist_slab_cache(struct kmem_cache *cachep, 1938 size_t size, unsigned long flags) 1939 { 1940 size_t left; 1941 1942 cachep->num = 0; 1943 1944 if (cachep->ctor || flags & SLAB_DESTROY_BY_RCU) 1945 return false; 1946 1947 left = calculate_slab_order(cachep, size, 1948 flags | CFLGS_OBJFREELIST_SLAB); 1949 if (!cachep->num) 1950 return false; 1951 1952 if (cachep->num * sizeof(freelist_idx_t) > cachep->object_size) 1953 return false; 1954 1955 cachep->colour = left / cachep->colour_off; 1956 1957 return true; 1958 } 1959 1960 static bool set_off_slab_cache(struct kmem_cache *cachep, 1961 size_t size, unsigned long flags) 1962 { 1963 size_t left; 1964 1965 cachep->num = 0; 1966 1967 /* 1968 * Always use on-slab management when SLAB_NOLEAKTRACE 1969 * to avoid recursive calls into kmemleak. 1970 */ 1971 if (flags & SLAB_NOLEAKTRACE) 1972 return false; 1973 1974 /* 1975 * Size is large, assume best to place the slab management obj 1976 * off-slab (should allow better packing of objs). 1977 */ 1978 left = calculate_slab_order(cachep, size, flags | CFLGS_OFF_SLAB); 1979 if (!cachep->num) 1980 return false; 1981 1982 /* 1983 * If the slab has been placed off-slab, and we have enough space then 1984 * move it on-slab. This is at the expense of any extra colouring. 1985 */ 1986 if (left >= cachep->num * sizeof(freelist_idx_t)) 1987 return false; 1988 1989 cachep->colour = left / cachep->colour_off; 1990 1991 return true; 1992 } 1993 1994 static bool set_on_slab_cache(struct kmem_cache *cachep, 1995 size_t size, unsigned long flags) 1996 { 1997 size_t left; 1998 1999 cachep->num = 0; 2000 2001 left = calculate_slab_order(cachep, size, flags); 2002 if (!cachep->num) 2003 return false; 2004 2005 cachep->colour = left / cachep->colour_off; 2006 2007 return true; 2008 } 2009 2010 /** 2011 * __kmem_cache_create - Create a cache. 2012 * @cachep: cache management descriptor 2013 * @flags: SLAB flags 2014 * 2015 * Returns a ptr to the cache on success, NULL on failure. 2016 * Cannot be called within a int, but can be interrupted. 2017 * The @ctor is run when new pages are allocated by the cache. 2018 * 2019 * The flags are 2020 * 2021 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 2022 * to catch references to uninitialised memory. 2023 * 2024 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 2025 * for buffer overruns. 2026 * 2027 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 2028 * cacheline. This can be beneficial if you're counting cycles as closely 2029 * as davem. 2030 */ 2031 int 2032 __kmem_cache_create (struct kmem_cache *cachep, unsigned long flags) 2033 { 2034 size_t ralign = BYTES_PER_WORD; 2035 gfp_t gfp; 2036 int err; 2037 size_t size = cachep->size; 2038 2039 #if DEBUG 2040 #if FORCED_DEBUG 2041 /* 2042 * Enable redzoning and last user accounting, except for caches with 2043 * large objects, if the increased size would increase the object size 2044 * above the next power of two: caches with object sizes just above a 2045 * power of two have a significant amount of internal fragmentation. 2046 */ 2047 if (size < 4096 || fls(size - 1) == fls(size-1 + REDZONE_ALIGN + 2048 2 * sizeof(unsigned long long))) 2049 flags |= SLAB_RED_ZONE | SLAB_STORE_USER; 2050 if (!(flags & SLAB_DESTROY_BY_RCU)) 2051 flags |= SLAB_POISON; 2052 #endif 2053 #endif 2054 2055 /* 2056 * Check that size is in terms of words. This is needed to avoid 2057 * unaligned accesses for some archs when redzoning is used, and makes 2058 * sure any on-slab bufctl's are also correctly aligned. 2059 */ 2060 if (size & (BYTES_PER_WORD - 1)) { 2061 size += (BYTES_PER_WORD - 1); 2062 size &= ~(BYTES_PER_WORD - 1); 2063 } 2064 2065 if (flags & SLAB_RED_ZONE) { 2066 ralign = REDZONE_ALIGN; 2067 /* If redzoning, ensure that the second redzone is suitably 2068 * aligned, by adjusting the object size accordingly. */ 2069 size += REDZONE_ALIGN - 1; 2070 size &= ~(REDZONE_ALIGN - 1); 2071 } 2072 2073 /* 3) caller mandated alignment */ 2074 if (ralign < cachep->align) { 2075 ralign = cachep->align; 2076 } 2077 /* disable debug if necessary */ 2078 if (ralign > __alignof__(unsigned long long)) 2079 flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); 2080 /* 2081 * 4) Store it. 2082 */ 2083 cachep->align = ralign; 2084 cachep->colour_off = cache_line_size(); 2085 /* Offset must be a multiple of the alignment. */ 2086 if (cachep->colour_off < cachep->align) 2087 cachep->colour_off = cachep->align; 2088 2089 if (slab_is_available()) 2090 gfp = GFP_KERNEL; 2091 else 2092 gfp = GFP_NOWAIT; 2093 2094 #if DEBUG 2095 2096 /* 2097 * Both debugging options require word-alignment which is calculated 2098 * into align above. 2099 */ 2100 if (flags & SLAB_RED_ZONE) { 2101 /* add space for red zone words */ 2102 cachep->obj_offset += sizeof(unsigned long long); 2103 size += 2 * sizeof(unsigned long long); 2104 } 2105 if (flags & SLAB_STORE_USER) { 2106 /* user store requires one word storage behind the end of 2107 * the real object. But if the second red zone needs to be 2108 * aligned to 64 bits, we must allow that much space. 2109 */ 2110 if (flags & SLAB_RED_ZONE) 2111 size += REDZONE_ALIGN; 2112 else 2113 size += BYTES_PER_WORD; 2114 } 2115 #endif 2116 2117 kasan_cache_create(cachep, &size, &flags); 2118 2119 size = ALIGN(size, cachep->align); 2120 /* 2121 * We should restrict the number of objects in a slab to implement 2122 * byte sized index. Refer comment on SLAB_OBJ_MIN_SIZE definition. 2123 */ 2124 if (FREELIST_BYTE_INDEX && size < SLAB_OBJ_MIN_SIZE) 2125 size = ALIGN(SLAB_OBJ_MIN_SIZE, cachep->align); 2126 2127 #if DEBUG 2128 /* 2129 * To activate debug pagealloc, off-slab management is necessary 2130 * requirement. In early phase of initialization, small sized slab 2131 * doesn't get initialized so it would not be possible. So, we need 2132 * to check size >= 256. It guarantees that all necessary small 2133 * sized slab is initialized in current slab initialization sequence. 2134 */ 2135 if (debug_pagealloc_enabled() && (flags & SLAB_POISON) && 2136 size >= 256 && cachep->object_size > cache_line_size()) { 2137 if (size < PAGE_SIZE || size % PAGE_SIZE == 0) { 2138 size_t tmp_size = ALIGN(size, PAGE_SIZE); 2139 2140 if (set_off_slab_cache(cachep, tmp_size, flags)) { 2141 flags |= CFLGS_OFF_SLAB; 2142 cachep->obj_offset += tmp_size - size; 2143 size = tmp_size; 2144 goto done; 2145 } 2146 } 2147 } 2148 #endif 2149 2150 if (set_objfreelist_slab_cache(cachep, size, flags)) { 2151 flags |= CFLGS_OBJFREELIST_SLAB; 2152 goto done; 2153 } 2154 2155 if (set_off_slab_cache(cachep, size, flags)) { 2156 flags |= CFLGS_OFF_SLAB; 2157 goto done; 2158 } 2159 2160 if (set_on_slab_cache(cachep, size, flags)) 2161 goto done; 2162 2163 return -E2BIG; 2164 2165 done: 2166 cachep->freelist_size = cachep->num * sizeof(freelist_idx_t); 2167 cachep->flags = flags; 2168 cachep->allocflags = __GFP_COMP; 2169 if (flags & SLAB_CACHE_DMA) 2170 cachep->allocflags |= GFP_DMA; 2171 cachep->size = size; 2172 cachep->reciprocal_buffer_size = reciprocal_value(size); 2173 2174 #if DEBUG 2175 /* 2176 * If we're going to use the generic kernel_map_pages() 2177 * poisoning, then it's going to smash the contents of 2178 * the redzone and userword anyhow, so switch them off. 2179 */ 2180 if (IS_ENABLED(CONFIG_PAGE_POISONING) && 2181 (cachep->flags & SLAB_POISON) && 2182 is_debug_pagealloc_cache(cachep)) 2183 cachep->flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER); 2184 #endif 2185 2186 if (OFF_SLAB(cachep)) { 2187 cachep->freelist_cache = 2188 kmalloc_slab(cachep->freelist_size, 0u); 2189 } 2190 2191 err = setup_cpu_cache(cachep, gfp); 2192 if (err) { 2193 __kmem_cache_release(cachep); 2194 return err; 2195 } 2196 2197 return 0; 2198 } 2199 2200 #if DEBUG 2201 static void check_irq_off(void) 2202 { 2203 BUG_ON(!irqs_disabled()); 2204 } 2205 2206 static void check_irq_on(void) 2207 { 2208 BUG_ON(irqs_disabled()); 2209 } 2210 2211 static void check_mutex_acquired(void) 2212 { 2213 BUG_ON(!mutex_is_locked(&slab_mutex)); 2214 } 2215 2216 static void check_spinlock_acquired(struct kmem_cache *cachep) 2217 { 2218 #ifdef CONFIG_SMP 2219 check_irq_off(); 2220 assert_spin_locked(&get_node(cachep, numa_mem_id())->list_lock); 2221 #endif 2222 } 2223 2224 static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node) 2225 { 2226 #ifdef CONFIG_SMP 2227 check_irq_off(); 2228 assert_spin_locked(&get_node(cachep, node)->list_lock); 2229 #endif 2230 } 2231 2232 #else 2233 #define check_irq_off() do { } while(0) 2234 #define check_irq_on() do { } while(0) 2235 #define check_mutex_acquired() do { } while(0) 2236 #define check_spinlock_acquired(x) do { } while(0) 2237 #define check_spinlock_acquired_node(x, y) do { } while(0) 2238 #endif 2239 2240 static void drain_array_locked(struct kmem_cache *cachep, struct array_cache *ac, 2241 int node, bool free_all, struct list_head *list) 2242 { 2243 int tofree; 2244 2245 if (!ac || !ac->avail) 2246 return; 2247 2248 tofree = free_all ? ac->avail : (ac->limit + 4) / 5; 2249 if (tofree > ac->avail) 2250 tofree = (ac->avail + 1) / 2; 2251 2252 free_block(cachep, ac->entry, tofree, node, list); 2253 ac->avail -= tofree; 2254 memmove(ac->entry, &(ac->entry[tofree]), sizeof(void *) * ac->avail); 2255 } 2256 2257 static void do_drain(void *arg) 2258 { 2259 struct kmem_cache *cachep = arg; 2260 struct array_cache *ac; 2261 int node = numa_mem_id(); 2262 struct kmem_cache_node *n; 2263 LIST_HEAD(list); 2264 2265 check_irq_off(); 2266 ac = cpu_cache_get(cachep); 2267 n = get_node(cachep, node); 2268 spin_lock(&n->list_lock); 2269 free_block(cachep, ac->entry, ac->avail, node, &list); 2270 spin_unlock(&n->list_lock); 2271 slabs_destroy(cachep, &list); 2272 ac->avail = 0; 2273 } 2274 2275 static void drain_cpu_caches(struct kmem_cache *cachep) 2276 { 2277 struct kmem_cache_node *n; 2278 int node; 2279 LIST_HEAD(list); 2280 2281 on_each_cpu(do_drain, cachep, 1); 2282 check_irq_on(); 2283 for_each_kmem_cache_node(cachep, node, n) 2284 if (n->alien) 2285 drain_alien_cache(cachep, n->alien); 2286 2287 for_each_kmem_cache_node(cachep, node, n) { 2288 spin_lock_irq(&n->list_lock); 2289 drain_array_locked(cachep, n->shared, node, true, &list); 2290 spin_unlock_irq(&n->list_lock); 2291 2292 slabs_destroy(cachep, &list); 2293 } 2294 } 2295 2296 /* 2297 * Remove slabs from the list of free slabs. 2298 * Specify the number of slabs to drain in tofree. 2299 * 2300 * Returns the actual number of slabs released. 2301 */ 2302 static int drain_freelist(struct kmem_cache *cache, 2303 struct kmem_cache_node *n, int tofree) 2304 { 2305 struct list_head *p; 2306 int nr_freed; 2307 struct page *page; 2308 2309 nr_freed = 0; 2310 while (nr_freed < tofree && !list_empty(&n->slabs_free)) { 2311 2312 spin_lock_irq(&n->list_lock); 2313 p = n->slabs_free.prev; 2314 if (p == &n->slabs_free) { 2315 spin_unlock_irq(&n->list_lock); 2316 goto out; 2317 } 2318 2319 page = list_entry(p, struct page, lru); 2320 list_del(&page->lru); 2321 n->num_slabs--; 2322 /* 2323 * Safe to drop the lock. The slab is no longer linked 2324 * to the cache. 2325 */ 2326 n->free_objects -= cache->num; 2327 spin_unlock_irq(&n->list_lock); 2328 slab_destroy(cache, page); 2329 nr_freed++; 2330 } 2331 out: 2332 return nr_freed; 2333 } 2334 2335 int __kmem_cache_shrink(struct kmem_cache *cachep, bool deactivate) 2336 { 2337 int ret = 0; 2338 int node; 2339 struct kmem_cache_node *n; 2340 2341 drain_cpu_caches(cachep); 2342 2343 check_irq_on(); 2344 for_each_kmem_cache_node(cachep, node, n) { 2345 drain_freelist(cachep, n, INT_MAX); 2346 2347 ret += !list_empty(&n->slabs_full) || 2348 !list_empty(&n->slabs_partial); 2349 } 2350 return (ret ? 1 : 0); 2351 } 2352 2353 int __kmem_cache_shutdown(struct kmem_cache *cachep) 2354 { 2355 return __kmem_cache_shrink(cachep, false); 2356 } 2357 2358 void __kmem_cache_release(struct kmem_cache *cachep) 2359 { 2360 int i; 2361 struct kmem_cache_node *n; 2362 2363 cache_random_seq_destroy(cachep); 2364 2365 free_percpu(cachep->cpu_cache); 2366 2367 /* NUMA: free the node structures */ 2368 for_each_kmem_cache_node(cachep, i, n) { 2369 kfree(n->shared); 2370 free_alien_cache(n->alien); 2371 kfree(n); 2372 cachep->node[i] = NULL; 2373 } 2374 } 2375 2376 /* 2377 * Get the memory for a slab management obj. 2378 * 2379 * For a slab cache when the slab descriptor is off-slab, the 2380 * slab descriptor can't come from the same cache which is being created, 2381 * Because if it is the case, that means we defer the creation of 2382 * the kmalloc_{dma,}_cache of size sizeof(slab descriptor) to this point. 2383 * And we eventually call down to __kmem_cache_create(), which 2384 * in turn looks up in the kmalloc_{dma,}_caches for the disired-size one. 2385 * This is a "chicken-and-egg" problem. 2386 * 2387 * So the off-slab slab descriptor shall come from the kmalloc_{dma,}_caches, 2388 * which are all initialized during kmem_cache_init(). 2389 */ 2390 static void *alloc_slabmgmt(struct kmem_cache *cachep, 2391 struct page *page, int colour_off, 2392 gfp_t local_flags, int nodeid) 2393 { 2394 void *freelist; 2395 void *addr = page_address(page); 2396 2397 page->s_mem = addr + colour_off; 2398 page->active = 0; 2399 2400 if (OBJFREELIST_SLAB(cachep)) 2401 freelist = NULL; 2402 else if (OFF_SLAB(cachep)) { 2403 /* Slab management obj is off-slab. */ 2404 freelist = kmem_cache_alloc_node(cachep->freelist_cache, 2405 local_flags, nodeid); 2406 if (!freelist) 2407 return NULL; 2408 } else { 2409 /* We will use last bytes at the slab for freelist */ 2410 freelist = addr + (PAGE_SIZE << cachep->gfporder) - 2411 cachep->freelist_size; 2412 } 2413 2414 return freelist; 2415 } 2416 2417 static inline freelist_idx_t get_free_obj(struct page *page, unsigned int idx) 2418 { 2419 return ((freelist_idx_t *)page->freelist)[idx]; 2420 } 2421 2422 static inline void set_free_obj(struct page *page, 2423 unsigned int idx, freelist_idx_t val) 2424 { 2425 ((freelist_idx_t *)(page->freelist))[idx] = val; 2426 } 2427 2428 static void cache_init_objs_debug(struct kmem_cache *cachep, struct page *page) 2429 { 2430 #if DEBUG 2431 int i; 2432 2433 for (i = 0; i < cachep->num; i++) { 2434 void *objp = index_to_obj(cachep, page, i); 2435 2436 if (cachep->flags & SLAB_STORE_USER) 2437 *dbg_userword(cachep, objp) = NULL; 2438 2439 if (cachep->flags & SLAB_RED_ZONE) { 2440 *dbg_redzone1(cachep, objp) = RED_INACTIVE; 2441 *dbg_redzone2(cachep, objp) = RED_INACTIVE; 2442 } 2443 /* 2444 * Constructors are not allowed to allocate memory from the same 2445 * cache which they are a constructor for. Otherwise, deadlock. 2446 * They must also be threaded. 2447 */ 2448 if (cachep->ctor && !(cachep->flags & SLAB_POISON)) { 2449 kasan_unpoison_object_data(cachep, 2450 objp + obj_offset(cachep)); 2451 cachep->ctor(objp + obj_offset(cachep)); 2452 kasan_poison_object_data( 2453 cachep, objp + obj_offset(cachep)); 2454 } 2455 2456 if (cachep->flags & SLAB_RED_ZONE) { 2457 if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) 2458 slab_error(cachep, "constructor overwrote the end of an object"); 2459 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) 2460 slab_error(cachep, "constructor overwrote the start of an object"); 2461 } 2462 /* need to poison the objs? */ 2463 if (cachep->flags & SLAB_POISON) { 2464 poison_obj(cachep, objp, POISON_FREE); 2465 slab_kernel_map(cachep, objp, 0, 0); 2466 } 2467 } 2468 #endif 2469 } 2470 2471 #ifdef CONFIG_SLAB_FREELIST_RANDOM 2472 /* Hold information during a freelist initialization */ 2473 union freelist_init_state { 2474 struct { 2475 unsigned int pos; 2476 unsigned int *list; 2477 unsigned int count; 2478 unsigned int rand; 2479 }; 2480 struct rnd_state rnd_state; 2481 }; 2482 2483 /* 2484 * Initialize the state based on the randomization methode available. 2485 * return true if the pre-computed list is available, false otherwize. 2486 */ 2487 static bool freelist_state_initialize(union freelist_init_state *state, 2488 struct kmem_cache *cachep, 2489 unsigned int count) 2490 { 2491 bool ret; 2492 unsigned int rand; 2493 2494 /* Use best entropy available to define a random shift */ 2495 rand = get_random_int(); 2496 2497 /* Use a random state if the pre-computed list is not available */ 2498 if (!cachep->random_seq) { 2499 prandom_seed_state(&state->rnd_state, rand); 2500 ret = false; 2501 } else { 2502 state->list = cachep->random_seq; 2503 state->count = count; 2504 state->pos = 0; 2505 state->rand = rand; 2506 ret = true; 2507 } 2508 return ret; 2509 } 2510 2511 /* Get the next entry on the list and randomize it using a random shift */ 2512 static freelist_idx_t next_random_slot(union freelist_init_state *state) 2513 { 2514 return (state->list[state->pos++] + state->rand) % state->count; 2515 } 2516 2517 /* Swap two freelist entries */ 2518 static void swap_free_obj(struct page *page, unsigned int a, unsigned int b) 2519 { 2520 swap(((freelist_idx_t *)page->freelist)[a], 2521 ((freelist_idx_t *)page->freelist)[b]); 2522 } 2523 2524 /* 2525 * Shuffle the freelist initialization state based on pre-computed lists. 2526 * return true if the list was successfully shuffled, false otherwise. 2527 */ 2528 static bool shuffle_freelist(struct kmem_cache *cachep, struct page *page) 2529 { 2530 unsigned int objfreelist = 0, i, rand, count = cachep->num; 2531 union freelist_init_state state; 2532 bool precomputed; 2533 2534 if (count < 2) 2535 return false; 2536 2537 precomputed = freelist_state_initialize(&state, cachep, count); 2538 2539 /* Take a random entry as the objfreelist */ 2540 if (OBJFREELIST_SLAB(cachep)) { 2541 if (!precomputed) 2542 objfreelist = count - 1; 2543 else 2544 objfreelist = next_random_slot(&state); 2545 page->freelist = index_to_obj(cachep, page, objfreelist) + 2546 obj_offset(cachep); 2547 count--; 2548 } 2549 2550 /* 2551 * On early boot, generate the list dynamically. 2552 * Later use a pre-computed list for speed. 2553 */ 2554 if (!precomputed) { 2555 for (i = 0; i < count; i++) 2556 set_free_obj(page, i, i); 2557 2558 /* Fisher-Yates shuffle */ 2559 for (i = count - 1; i > 0; i--) { 2560 rand = prandom_u32_state(&state.rnd_state); 2561 rand %= (i + 1); 2562 swap_free_obj(page, i, rand); 2563 } 2564 } else { 2565 for (i = 0; i < count; i++) 2566 set_free_obj(page, i, next_random_slot(&state)); 2567 } 2568 2569 if (OBJFREELIST_SLAB(cachep)) 2570 set_free_obj(page, cachep->num - 1, objfreelist); 2571 2572 return true; 2573 } 2574 #else 2575 static inline bool shuffle_freelist(struct kmem_cache *cachep, 2576 struct page *page) 2577 { 2578 return false; 2579 } 2580 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 2581 2582 static void cache_init_objs(struct kmem_cache *cachep, 2583 struct page *page) 2584 { 2585 int i; 2586 void *objp; 2587 bool shuffled; 2588 2589 cache_init_objs_debug(cachep, page); 2590 2591 /* Try to randomize the freelist if enabled */ 2592 shuffled = shuffle_freelist(cachep, page); 2593 2594 if (!shuffled && OBJFREELIST_SLAB(cachep)) { 2595 page->freelist = index_to_obj(cachep, page, cachep->num - 1) + 2596 obj_offset(cachep); 2597 } 2598 2599 for (i = 0; i < cachep->num; i++) { 2600 objp = index_to_obj(cachep, page, i); 2601 kasan_init_slab_obj(cachep, objp); 2602 2603 /* constructor could break poison info */ 2604 if (DEBUG == 0 && cachep->ctor) { 2605 kasan_unpoison_object_data(cachep, objp); 2606 cachep->ctor(objp); 2607 kasan_poison_object_data(cachep, objp); 2608 } 2609 2610 if (!shuffled) 2611 set_free_obj(page, i, i); 2612 } 2613 } 2614 2615 static void *slab_get_obj(struct kmem_cache *cachep, struct page *page) 2616 { 2617 void *objp; 2618 2619 objp = index_to_obj(cachep, page, get_free_obj(page, page->active)); 2620 page->active++; 2621 2622 #if DEBUG 2623 if (cachep->flags & SLAB_STORE_USER) 2624 set_store_user_dirty(cachep); 2625 #endif 2626 2627 return objp; 2628 } 2629 2630 static void slab_put_obj(struct kmem_cache *cachep, 2631 struct page *page, void *objp) 2632 { 2633 unsigned int objnr = obj_to_index(cachep, page, objp); 2634 #if DEBUG 2635 unsigned int i; 2636 2637 /* Verify double free bug */ 2638 for (i = page->active; i < cachep->num; i++) { 2639 if (get_free_obj(page, i) == objnr) { 2640 pr_err("slab: double free detected in cache '%s', objp %p\n", 2641 cachep->name, objp); 2642 BUG(); 2643 } 2644 } 2645 #endif 2646 page->active--; 2647 if (!page->freelist) 2648 page->freelist = objp + obj_offset(cachep); 2649 2650 set_free_obj(page, page->active, objnr); 2651 } 2652 2653 /* 2654 * Map pages beginning at addr to the given cache and slab. This is required 2655 * for the slab allocator to be able to lookup the cache and slab of a 2656 * virtual address for kfree, ksize, and slab debugging. 2657 */ 2658 static void slab_map_pages(struct kmem_cache *cache, struct page *page, 2659 void *freelist) 2660 { 2661 page->slab_cache = cache; 2662 page->freelist = freelist; 2663 } 2664 2665 /* 2666 * Grow (by 1) the number of slabs within a cache. This is called by 2667 * kmem_cache_alloc() when there are no active objs left in a cache. 2668 */ 2669 static struct page *cache_grow_begin(struct kmem_cache *cachep, 2670 gfp_t flags, int nodeid) 2671 { 2672 void *freelist; 2673 size_t offset; 2674 gfp_t local_flags; 2675 int page_node; 2676 struct kmem_cache_node *n; 2677 struct page *page; 2678 2679 /* 2680 * Be lazy and only check for valid flags here, keeping it out of the 2681 * critical path in kmem_cache_alloc(). 2682 */ 2683 if (unlikely(flags & GFP_SLAB_BUG_MASK)) { 2684 gfp_t invalid_mask = flags & GFP_SLAB_BUG_MASK; 2685 flags &= ~GFP_SLAB_BUG_MASK; 2686 pr_warn("Unexpected gfp: %#x (%pGg). Fixing up to gfp: %#x (%pGg). Fix your code!\n", 2687 invalid_mask, &invalid_mask, flags, &flags); 2688 dump_stack(); 2689 } 2690 local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK); 2691 2692 check_irq_off(); 2693 if (gfpflags_allow_blocking(local_flags)) 2694 local_irq_enable(); 2695 2696 /* 2697 * Get mem for the objs. Attempt to allocate a physical page from 2698 * 'nodeid'. 2699 */ 2700 page = kmem_getpages(cachep, local_flags, nodeid); 2701 if (!page) 2702 goto failed; 2703 2704 page_node = page_to_nid(page); 2705 n = get_node(cachep, page_node); 2706 2707 /* Get colour for the slab, and cal the next value. */ 2708 n->colour_next++; 2709 if (n->colour_next >= cachep->colour) 2710 n->colour_next = 0; 2711 2712 offset = n->colour_next; 2713 if (offset >= cachep->colour) 2714 offset = 0; 2715 2716 offset *= cachep->colour_off; 2717 2718 /* Get slab management. */ 2719 freelist = alloc_slabmgmt(cachep, page, offset, 2720 local_flags & ~GFP_CONSTRAINT_MASK, page_node); 2721 if (OFF_SLAB(cachep) && !freelist) 2722 goto opps1; 2723 2724 slab_map_pages(cachep, page, freelist); 2725 2726 kasan_poison_slab(page); 2727 cache_init_objs(cachep, page); 2728 2729 if (gfpflags_allow_blocking(local_flags)) 2730 local_irq_disable(); 2731 2732 return page; 2733 2734 opps1: 2735 kmem_freepages(cachep, page); 2736 failed: 2737 if (gfpflags_allow_blocking(local_flags)) 2738 local_irq_disable(); 2739 return NULL; 2740 } 2741 2742 static void cache_grow_end(struct kmem_cache *cachep, struct page *page) 2743 { 2744 struct kmem_cache_node *n; 2745 void *list = NULL; 2746 2747 check_irq_off(); 2748 2749 if (!page) 2750 return; 2751 2752 INIT_LIST_HEAD(&page->lru); 2753 n = get_node(cachep, page_to_nid(page)); 2754 2755 spin_lock(&n->list_lock); 2756 if (!page->active) 2757 list_add_tail(&page->lru, &(n->slabs_free)); 2758 else 2759 fixup_slab_list(cachep, n, page, &list); 2760 2761 n->num_slabs++; 2762 STATS_INC_GROWN(cachep); 2763 n->free_objects += cachep->num - page->active; 2764 spin_unlock(&n->list_lock); 2765 2766 fixup_objfreelist_debug(cachep, &list); 2767 } 2768 2769 #if DEBUG 2770 2771 /* 2772 * Perform extra freeing checks: 2773 * - detect bad pointers. 2774 * - POISON/RED_ZONE checking 2775 */ 2776 static void kfree_debugcheck(const void *objp) 2777 { 2778 if (!virt_addr_valid(objp)) { 2779 pr_err("kfree_debugcheck: out of range ptr %lxh\n", 2780 (unsigned long)objp); 2781 BUG(); 2782 } 2783 } 2784 2785 static inline void verify_redzone_free(struct kmem_cache *cache, void *obj) 2786 { 2787 unsigned long long redzone1, redzone2; 2788 2789 redzone1 = *dbg_redzone1(cache, obj); 2790 redzone2 = *dbg_redzone2(cache, obj); 2791 2792 /* 2793 * Redzone is ok. 2794 */ 2795 if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE) 2796 return; 2797 2798 if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE) 2799 slab_error(cache, "double free detected"); 2800 else 2801 slab_error(cache, "memory outside object was overwritten"); 2802 2803 pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n", 2804 obj, redzone1, redzone2); 2805 } 2806 2807 static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp, 2808 unsigned long caller) 2809 { 2810 unsigned int objnr; 2811 struct page *page; 2812 2813 BUG_ON(virt_to_cache(objp) != cachep); 2814 2815 objp -= obj_offset(cachep); 2816 kfree_debugcheck(objp); 2817 page = virt_to_head_page(objp); 2818 2819 if (cachep->flags & SLAB_RED_ZONE) { 2820 verify_redzone_free(cachep, objp); 2821 *dbg_redzone1(cachep, objp) = RED_INACTIVE; 2822 *dbg_redzone2(cachep, objp) = RED_INACTIVE; 2823 } 2824 if (cachep->flags & SLAB_STORE_USER) { 2825 set_store_user_dirty(cachep); 2826 *dbg_userword(cachep, objp) = (void *)caller; 2827 } 2828 2829 objnr = obj_to_index(cachep, page, objp); 2830 2831 BUG_ON(objnr >= cachep->num); 2832 BUG_ON(objp != index_to_obj(cachep, page, objnr)); 2833 2834 if (cachep->flags & SLAB_POISON) { 2835 poison_obj(cachep, objp, POISON_FREE); 2836 slab_kernel_map(cachep, objp, 0, caller); 2837 } 2838 return objp; 2839 } 2840 2841 #else 2842 #define kfree_debugcheck(x) do { } while(0) 2843 #define cache_free_debugcheck(x,objp,z) (objp) 2844 #endif 2845 2846 static inline void fixup_objfreelist_debug(struct kmem_cache *cachep, 2847 void **list) 2848 { 2849 #if DEBUG 2850 void *next = *list; 2851 void *objp; 2852 2853 while (next) { 2854 objp = next - obj_offset(cachep); 2855 next = *(void **)next; 2856 poison_obj(cachep, objp, POISON_FREE); 2857 } 2858 #endif 2859 } 2860 2861 static inline void fixup_slab_list(struct kmem_cache *cachep, 2862 struct kmem_cache_node *n, struct page *page, 2863 void **list) 2864 { 2865 /* move slabp to correct slabp list: */ 2866 list_del(&page->lru); 2867 if (page->active == cachep->num) { 2868 list_add(&page->lru, &n->slabs_full); 2869 if (OBJFREELIST_SLAB(cachep)) { 2870 #if DEBUG 2871 /* Poisoning will be done without holding the lock */ 2872 if (cachep->flags & SLAB_POISON) { 2873 void **objp = page->freelist; 2874 2875 *objp = *list; 2876 *list = objp; 2877 } 2878 #endif 2879 page->freelist = NULL; 2880 } 2881 } else 2882 list_add(&page->lru, &n->slabs_partial); 2883 } 2884 2885 /* Try to find non-pfmemalloc slab if needed */ 2886 static noinline struct page *get_valid_first_slab(struct kmem_cache_node *n, 2887 struct page *page, bool pfmemalloc) 2888 { 2889 if (!page) 2890 return NULL; 2891 2892 if (pfmemalloc) 2893 return page; 2894 2895 if (!PageSlabPfmemalloc(page)) 2896 return page; 2897 2898 /* No need to keep pfmemalloc slab if we have enough free objects */ 2899 if (n->free_objects > n->free_limit) { 2900 ClearPageSlabPfmemalloc(page); 2901 return page; 2902 } 2903 2904 /* Move pfmemalloc slab to the end of list to speed up next search */ 2905 list_del(&page->lru); 2906 if (!page->active) 2907 list_add_tail(&page->lru, &n->slabs_free); 2908 else 2909 list_add_tail(&page->lru, &n->slabs_partial); 2910 2911 list_for_each_entry(page, &n->slabs_partial, lru) { 2912 if (!PageSlabPfmemalloc(page)) 2913 return page; 2914 } 2915 2916 list_for_each_entry(page, &n->slabs_free, lru) { 2917 if (!PageSlabPfmemalloc(page)) 2918 return page; 2919 } 2920 2921 return NULL; 2922 } 2923 2924 static struct page *get_first_slab(struct kmem_cache_node *n, bool pfmemalloc) 2925 { 2926 struct page *page; 2927 2928 page = list_first_entry_or_null(&n->slabs_partial, 2929 struct page, lru); 2930 if (!page) { 2931 n->free_touched = 1; 2932 page = list_first_entry_or_null(&n->slabs_free, 2933 struct page, lru); 2934 } 2935 2936 if (sk_memalloc_socks()) 2937 return get_valid_first_slab(n, page, pfmemalloc); 2938 2939 return page; 2940 } 2941 2942 static noinline void *cache_alloc_pfmemalloc(struct kmem_cache *cachep, 2943 struct kmem_cache_node *n, gfp_t flags) 2944 { 2945 struct page *page; 2946 void *obj; 2947 void *list = NULL; 2948 2949 if (!gfp_pfmemalloc_allowed(flags)) 2950 return NULL; 2951 2952 spin_lock(&n->list_lock); 2953 page = get_first_slab(n, true); 2954 if (!page) { 2955 spin_unlock(&n->list_lock); 2956 return NULL; 2957 } 2958 2959 obj = slab_get_obj(cachep, page); 2960 n->free_objects--; 2961 2962 fixup_slab_list(cachep, n, page, &list); 2963 2964 spin_unlock(&n->list_lock); 2965 fixup_objfreelist_debug(cachep, &list); 2966 2967 return obj; 2968 } 2969 2970 /* 2971 * Slab list should be fixed up by fixup_slab_list() for existing slab 2972 * or cache_grow_end() for new slab 2973 */ 2974 static __always_inline int alloc_block(struct kmem_cache *cachep, 2975 struct array_cache *ac, struct page *page, int batchcount) 2976 { 2977 /* 2978 * There must be at least one object available for 2979 * allocation. 2980 */ 2981 BUG_ON(page->active >= cachep->num); 2982 2983 while (page->active < cachep->num && batchcount--) { 2984 STATS_INC_ALLOCED(cachep); 2985 STATS_INC_ACTIVE(cachep); 2986 STATS_SET_HIGH(cachep); 2987 2988 ac->entry[ac->avail++] = slab_get_obj(cachep, page); 2989 } 2990 2991 return batchcount; 2992 } 2993 2994 static void *cache_alloc_refill(struct kmem_cache *cachep, gfp_t flags) 2995 { 2996 int batchcount; 2997 struct kmem_cache_node *n; 2998 struct array_cache *ac, *shared; 2999 int node; 3000 void *list = NULL; 3001 struct page *page; 3002 3003 check_irq_off(); 3004 node = numa_mem_id(); 3005 3006 ac = cpu_cache_get(cachep); 3007 batchcount = ac->batchcount; 3008 if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { 3009 /* 3010 * If there was little recent activity on this cache, then 3011 * perform only a partial refill. Otherwise we could generate 3012 * refill bouncing. 3013 */ 3014 batchcount = BATCHREFILL_LIMIT; 3015 } 3016 n = get_node(cachep, node); 3017 3018 BUG_ON(ac->avail > 0 || !n); 3019 shared = READ_ONCE(n->shared); 3020 if (!n->free_objects && (!shared || !shared->avail)) 3021 goto direct_grow; 3022 3023 spin_lock(&n->list_lock); 3024 shared = READ_ONCE(n->shared); 3025 3026 /* See if we can refill from the shared array */ 3027 if (shared && transfer_objects(ac, shared, batchcount)) { 3028 shared->touched = 1; 3029 goto alloc_done; 3030 } 3031 3032 while (batchcount > 0) { 3033 /* Get slab alloc is to come from. */ 3034 page = get_first_slab(n, false); 3035 if (!page) 3036 goto must_grow; 3037 3038 check_spinlock_acquired(cachep); 3039 3040 batchcount = alloc_block(cachep, ac, page, batchcount); 3041 fixup_slab_list(cachep, n, page, &list); 3042 } 3043 3044 must_grow: 3045 n->free_objects -= ac->avail; 3046 alloc_done: 3047 spin_unlock(&n->list_lock); 3048 fixup_objfreelist_debug(cachep, &list); 3049 3050 direct_grow: 3051 if (unlikely(!ac->avail)) { 3052 /* Check if we can use obj in pfmemalloc slab */ 3053 if (sk_memalloc_socks()) { 3054 void *obj = cache_alloc_pfmemalloc(cachep, n, flags); 3055 3056 if (obj) 3057 return obj; 3058 } 3059 3060 page = cache_grow_begin(cachep, gfp_exact_node(flags), node); 3061 3062 /* 3063 * cache_grow_begin() can reenable interrupts, 3064 * then ac could change. 3065 */ 3066 ac = cpu_cache_get(cachep); 3067 if (!ac->avail && page) 3068 alloc_block(cachep, ac, page, batchcount); 3069 cache_grow_end(cachep, page); 3070 3071 if (!ac->avail) 3072 return NULL; 3073 } 3074 ac->touched = 1; 3075 3076 return ac->entry[--ac->avail]; 3077 } 3078 3079 static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep, 3080 gfp_t flags) 3081 { 3082 might_sleep_if(gfpflags_allow_blocking(flags)); 3083 } 3084 3085 #if DEBUG 3086 static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep, 3087 gfp_t flags, void *objp, unsigned long caller) 3088 { 3089 if (!objp) 3090 return objp; 3091 if (cachep->flags & SLAB_POISON) { 3092 check_poison_obj(cachep, objp); 3093 slab_kernel_map(cachep, objp, 1, 0); 3094 poison_obj(cachep, objp, POISON_INUSE); 3095 } 3096 if (cachep->flags & SLAB_STORE_USER) 3097 *dbg_userword(cachep, objp) = (void *)caller; 3098 3099 if (cachep->flags & SLAB_RED_ZONE) { 3100 if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || 3101 *dbg_redzone2(cachep, objp) != RED_INACTIVE) { 3102 slab_error(cachep, "double free, or memory outside object was overwritten"); 3103 pr_err("%p: redzone 1:0x%llx, redzone 2:0x%llx\n", 3104 objp, *dbg_redzone1(cachep, objp), 3105 *dbg_redzone2(cachep, objp)); 3106 } 3107 *dbg_redzone1(cachep, objp) = RED_ACTIVE; 3108 *dbg_redzone2(cachep, objp) = RED_ACTIVE; 3109 } 3110 3111 objp += obj_offset(cachep); 3112 if (cachep->ctor && cachep->flags & SLAB_POISON) 3113 cachep->ctor(objp); 3114 if (ARCH_SLAB_MINALIGN && 3115 ((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) { 3116 pr_err("0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n", 3117 objp, (int)ARCH_SLAB_MINALIGN); 3118 } 3119 return objp; 3120 } 3121 #else 3122 #define cache_alloc_debugcheck_after(a,b,objp,d) (objp) 3123 #endif 3124 3125 static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3126 { 3127 void *objp; 3128 struct array_cache *ac; 3129 3130 check_irq_off(); 3131 3132 ac = cpu_cache_get(cachep); 3133 if (likely(ac->avail)) { 3134 ac->touched = 1; 3135 objp = ac->entry[--ac->avail]; 3136 3137 STATS_INC_ALLOCHIT(cachep); 3138 goto out; 3139 } 3140 3141 STATS_INC_ALLOCMISS(cachep); 3142 objp = cache_alloc_refill(cachep, flags); 3143 /* 3144 * the 'ac' may be updated by cache_alloc_refill(), 3145 * and kmemleak_erase() requires its correct value. 3146 */ 3147 ac = cpu_cache_get(cachep); 3148 3149 out: 3150 /* 3151 * To avoid a false negative, if an object that is in one of the 3152 * per-CPU caches is leaked, we need to make sure kmemleak doesn't 3153 * treat the array pointers as a reference to the object. 3154 */ 3155 if (objp) 3156 kmemleak_erase(&ac->entry[ac->avail]); 3157 return objp; 3158 } 3159 3160 #ifdef CONFIG_NUMA 3161 /* 3162 * Try allocating on another node if PFA_SPREAD_SLAB is a mempolicy is set. 3163 * 3164 * If we are in_interrupt, then process context, including cpusets and 3165 * mempolicy, may not apply and should not be used for allocation policy. 3166 */ 3167 static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags) 3168 { 3169 int nid_alloc, nid_here; 3170 3171 if (in_interrupt() || (flags & __GFP_THISNODE)) 3172 return NULL; 3173 nid_alloc = nid_here = numa_mem_id(); 3174 if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD)) 3175 nid_alloc = cpuset_slab_spread_node(); 3176 else if (current->mempolicy) 3177 nid_alloc = mempolicy_slab_node(); 3178 if (nid_alloc != nid_here) 3179 return ____cache_alloc_node(cachep, flags, nid_alloc); 3180 return NULL; 3181 } 3182 3183 /* 3184 * Fallback function if there was no memory available and no objects on a 3185 * certain node and fall back is permitted. First we scan all the 3186 * available node for available objects. If that fails then we 3187 * perform an allocation without specifying a node. This allows the page 3188 * allocator to do its reclaim / fallback magic. We then insert the 3189 * slab into the proper nodelist and then allocate from it. 3190 */ 3191 static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags) 3192 { 3193 struct zonelist *zonelist; 3194 struct zoneref *z; 3195 struct zone *zone; 3196 enum zone_type high_zoneidx = gfp_zone(flags); 3197 void *obj = NULL; 3198 struct page *page; 3199 int nid; 3200 unsigned int cpuset_mems_cookie; 3201 3202 if (flags & __GFP_THISNODE) 3203 return NULL; 3204 3205 retry_cpuset: 3206 cpuset_mems_cookie = read_mems_allowed_begin(); 3207 zonelist = node_zonelist(mempolicy_slab_node(), flags); 3208 3209 retry: 3210 /* 3211 * Look through allowed nodes for objects available 3212 * from existing per node queues. 3213 */ 3214 for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { 3215 nid = zone_to_nid(zone); 3216 3217 if (cpuset_zone_allowed(zone, flags) && 3218 get_node(cache, nid) && 3219 get_node(cache, nid)->free_objects) { 3220 obj = ____cache_alloc_node(cache, 3221 gfp_exact_node(flags), nid); 3222 if (obj) 3223 break; 3224 } 3225 } 3226 3227 if (!obj) { 3228 /* 3229 * This allocation will be performed within the constraints 3230 * of the current cpuset / memory policy requirements. 3231 * We may trigger various forms of reclaim on the allowed 3232 * set and go into memory reserves if necessary. 3233 */ 3234 page = cache_grow_begin(cache, flags, numa_mem_id()); 3235 cache_grow_end(cache, page); 3236 if (page) { 3237 nid = page_to_nid(page); 3238 obj = ____cache_alloc_node(cache, 3239 gfp_exact_node(flags), nid); 3240 3241 /* 3242 * Another processor may allocate the objects in 3243 * the slab since we are not holding any locks. 3244 */ 3245 if (!obj) 3246 goto retry; 3247 } 3248 } 3249 3250 if (unlikely(!obj && read_mems_allowed_retry(cpuset_mems_cookie))) 3251 goto retry_cpuset; 3252 return obj; 3253 } 3254 3255 /* 3256 * A interface to enable slab creation on nodeid 3257 */ 3258 static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, 3259 int nodeid) 3260 { 3261 struct page *page; 3262 struct kmem_cache_node *n; 3263 void *obj = NULL; 3264 void *list = NULL; 3265 3266 VM_BUG_ON(nodeid < 0 || nodeid >= MAX_NUMNODES); 3267 n = get_node(cachep, nodeid); 3268 BUG_ON(!n); 3269 3270 check_irq_off(); 3271 spin_lock(&n->list_lock); 3272 page = get_first_slab(n, false); 3273 if (!page) 3274 goto must_grow; 3275 3276 check_spinlock_acquired_node(cachep, nodeid); 3277 3278 STATS_INC_NODEALLOCS(cachep); 3279 STATS_INC_ACTIVE(cachep); 3280 STATS_SET_HIGH(cachep); 3281 3282 BUG_ON(page->active == cachep->num); 3283 3284 obj = slab_get_obj(cachep, page); 3285 n->free_objects--; 3286 3287 fixup_slab_list(cachep, n, page, &list); 3288 3289 spin_unlock(&n->list_lock); 3290 fixup_objfreelist_debug(cachep, &list); 3291 return obj; 3292 3293 must_grow: 3294 spin_unlock(&n->list_lock); 3295 page = cache_grow_begin(cachep, gfp_exact_node(flags), nodeid); 3296 if (page) { 3297 /* This slab isn't counted yet so don't update free_objects */ 3298 obj = slab_get_obj(cachep, page); 3299 } 3300 cache_grow_end(cachep, page); 3301 3302 return obj ? obj : fallback_alloc(cachep, flags); 3303 } 3304 3305 static __always_inline void * 3306 slab_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid, 3307 unsigned long caller) 3308 { 3309 unsigned long save_flags; 3310 void *ptr; 3311 int slab_node = numa_mem_id(); 3312 3313 flags &= gfp_allowed_mask; 3314 cachep = slab_pre_alloc_hook(cachep, flags); 3315 if (unlikely(!cachep)) 3316 return NULL; 3317 3318 cache_alloc_debugcheck_before(cachep, flags); 3319 local_irq_save(save_flags); 3320 3321 if (nodeid == NUMA_NO_NODE) 3322 nodeid = slab_node; 3323 3324 if (unlikely(!get_node(cachep, nodeid))) { 3325 /* Node not bootstrapped yet */ 3326 ptr = fallback_alloc(cachep, flags); 3327 goto out; 3328 } 3329 3330 if (nodeid == slab_node) { 3331 /* 3332 * Use the locally cached objects if possible. 3333 * However ____cache_alloc does not allow fallback 3334 * to other nodes. It may fail while we still have 3335 * objects on other nodes available. 3336 */ 3337 ptr = ____cache_alloc(cachep, flags); 3338 if (ptr) 3339 goto out; 3340 } 3341 /* ___cache_alloc_node can fall back to other nodes */ 3342 ptr = ____cache_alloc_node(cachep, flags, nodeid); 3343 out: 3344 local_irq_restore(save_flags); 3345 ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller); 3346 3347 if (unlikely(flags & __GFP_ZERO) && ptr) 3348 memset(ptr, 0, cachep->object_size); 3349 3350 slab_post_alloc_hook(cachep, flags, 1, &ptr); 3351 return ptr; 3352 } 3353 3354 static __always_inline void * 3355 __do_cache_alloc(struct kmem_cache *cache, gfp_t flags) 3356 { 3357 void *objp; 3358 3359 if (current->mempolicy || cpuset_do_slab_mem_spread()) { 3360 objp = alternate_node_alloc(cache, flags); 3361 if (objp) 3362 goto out; 3363 } 3364 objp = ____cache_alloc(cache, flags); 3365 3366 /* 3367 * We may just have run out of memory on the local node. 3368 * ____cache_alloc_node() knows how to locate memory on other nodes 3369 */ 3370 if (!objp) 3371 objp = ____cache_alloc_node(cache, flags, numa_mem_id()); 3372 3373 out: 3374 return objp; 3375 } 3376 #else 3377 3378 static __always_inline void * 3379 __do_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3380 { 3381 return ____cache_alloc(cachep, flags); 3382 } 3383 3384 #endif /* CONFIG_NUMA */ 3385 3386 static __always_inline void * 3387 slab_alloc(struct kmem_cache *cachep, gfp_t flags, unsigned long caller) 3388 { 3389 unsigned long save_flags; 3390 void *objp; 3391 3392 flags &= gfp_allowed_mask; 3393 cachep = slab_pre_alloc_hook(cachep, flags); 3394 if (unlikely(!cachep)) 3395 return NULL; 3396 3397 cache_alloc_debugcheck_before(cachep, flags); 3398 local_irq_save(save_flags); 3399 objp = __do_cache_alloc(cachep, flags); 3400 local_irq_restore(save_flags); 3401 objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller); 3402 prefetchw(objp); 3403 3404 if (unlikely(flags & __GFP_ZERO) && objp) 3405 memset(objp, 0, cachep->object_size); 3406 3407 slab_post_alloc_hook(cachep, flags, 1, &objp); 3408 return objp; 3409 } 3410 3411 /* 3412 * Caller needs to acquire correct kmem_cache_node's list_lock 3413 * @list: List of detached free slabs should be freed by caller 3414 */ 3415 static void free_block(struct kmem_cache *cachep, void **objpp, 3416 int nr_objects, int node, struct list_head *list) 3417 { 3418 int i; 3419 struct kmem_cache_node *n = get_node(cachep, node); 3420 struct page *page; 3421 3422 n->free_objects += nr_objects; 3423 3424 for (i = 0; i < nr_objects; i++) { 3425 void *objp; 3426 struct page *page; 3427 3428 objp = objpp[i]; 3429 3430 page = virt_to_head_page(objp); 3431 list_del(&page->lru); 3432 check_spinlock_acquired_node(cachep, node); 3433 slab_put_obj(cachep, page, objp); 3434 STATS_DEC_ACTIVE(cachep); 3435 3436 /* fixup slab chains */ 3437 if (page->active == 0) 3438 list_add(&page->lru, &n->slabs_free); 3439 else { 3440 /* Unconditionally move a slab to the end of the 3441 * partial list on free - maximum time for the 3442 * other objects to be freed, too. 3443 */ 3444 list_add_tail(&page->lru, &n->slabs_partial); 3445 } 3446 } 3447 3448 while (n->free_objects > n->free_limit && !list_empty(&n->slabs_free)) { 3449 n->free_objects -= cachep->num; 3450 3451 page = list_last_entry(&n->slabs_free, struct page, lru); 3452 list_move(&page->lru, list); 3453 n->num_slabs--; 3454 } 3455 } 3456 3457 static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac) 3458 { 3459 int batchcount; 3460 struct kmem_cache_node *n; 3461 int node = numa_mem_id(); 3462 LIST_HEAD(list); 3463 3464 batchcount = ac->batchcount; 3465 3466 check_irq_off(); 3467 n = get_node(cachep, node); 3468 spin_lock(&n->list_lock); 3469 if (n->shared) { 3470 struct array_cache *shared_array = n->shared; 3471 int max = shared_array->limit - shared_array->avail; 3472 if (max) { 3473 if (batchcount > max) 3474 batchcount = max; 3475 memcpy(&(shared_array->entry[shared_array->avail]), 3476 ac->entry, sizeof(void *) * batchcount); 3477 shared_array->avail += batchcount; 3478 goto free_done; 3479 } 3480 } 3481 3482 free_block(cachep, ac->entry, batchcount, node, &list); 3483 free_done: 3484 #if STATS 3485 { 3486 int i = 0; 3487 struct page *page; 3488 3489 list_for_each_entry(page, &n->slabs_free, lru) { 3490 BUG_ON(page->active); 3491 3492 i++; 3493 } 3494 STATS_SET_FREEABLE(cachep, i); 3495 } 3496 #endif 3497 spin_unlock(&n->list_lock); 3498 slabs_destroy(cachep, &list); 3499 ac->avail -= batchcount; 3500 memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail); 3501 } 3502 3503 /* 3504 * Release an obj back to its cache. If the obj has a constructed state, it must 3505 * be in this state _before_ it is released. Called with disabled ints. 3506 */ 3507 static inline void __cache_free(struct kmem_cache *cachep, void *objp, 3508 unsigned long caller) 3509 { 3510 /* Put the object into the quarantine, don't touch it for now. */ 3511 if (kasan_slab_free(cachep, objp)) 3512 return; 3513 3514 ___cache_free(cachep, objp, caller); 3515 } 3516 3517 void ___cache_free(struct kmem_cache *cachep, void *objp, 3518 unsigned long caller) 3519 { 3520 struct array_cache *ac = cpu_cache_get(cachep); 3521 3522 check_irq_off(); 3523 kmemleak_free_recursive(objp, cachep->flags); 3524 objp = cache_free_debugcheck(cachep, objp, caller); 3525 3526 kmemcheck_slab_free(cachep, objp, cachep->object_size); 3527 3528 /* 3529 * Skip calling cache_free_alien() when the platform is not numa. 3530 * This will avoid cache misses that happen while accessing slabp (which 3531 * is per page memory reference) to get nodeid. Instead use a global 3532 * variable to skip the call, which is mostly likely to be present in 3533 * the cache. 3534 */ 3535 if (nr_online_nodes > 1 && cache_free_alien(cachep, objp)) 3536 return; 3537 3538 if (ac->avail < ac->limit) { 3539 STATS_INC_FREEHIT(cachep); 3540 } else { 3541 STATS_INC_FREEMISS(cachep); 3542 cache_flusharray(cachep, ac); 3543 } 3544 3545 if (sk_memalloc_socks()) { 3546 struct page *page = virt_to_head_page(objp); 3547 3548 if (unlikely(PageSlabPfmemalloc(page))) { 3549 cache_free_pfmemalloc(cachep, page, objp); 3550 return; 3551 } 3552 } 3553 3554 ac->entry[ac->avail++] = objp; 3555 } 3556 3557 /** 3558 * kmem_cache_alloc - Allocate an object 3559 * @cachep: The cache to allocate from. 3560 * @flags: See kmalloc(). 3561 * 3562 * Allocate an object from this cache. The flags are only relevant 3563 * if the cache has no available objects. 3564 */ 3565 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags) 3566 { 3567 void *ret = slab_alloc(cachep, flags, _RET_IP_); 3568 3569 kasan_slab_alloc(cachep, ret, flags); 3570 trace_kmem_cache_alloc(_RET_IP_, ret, 3571 cachep->object_size, cachep->size, flags); 3572 3573 return ret; 3574 } 3575 EXPORT_SYMBOL(kmem_cache_alloc); 3576 3577 static __always_inline void 3578 cache_alloc_debugcheck_after_bulk(struct kmem_cache *s, gfp_t flags, 3579 size_t size, void **p, unsigned long caller) 3580 { 3581 size_t i; 3582 3583 for (i = 0; i < size; i++) 3584 p[i] = cache_alloc_debugcheck_after(s, flags, p[i], caller); 3585 } 3586 3587 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size, 3588 void **p) 3589 { 3590 size_t i; 3591 3592 s = slab_pre_alloc_hook(s, flags); 3593 if (!s) 3594 return 0; 3595 3596 cache_alloc_debugcheck_before(s, flags); 3597 3598 local_irq_disable(); 3599 for (i = 0; i < size; i++) { 3600 void *objp = __do_cache_alloc(s, flags); 3601 3602 if (unlikely(!objp)) 3603 goto error; 3604 p[i] = objp; 3605 } 3606 local_irq_enable(); 3607 3608 cache_alloc_debugcheck_after_bulk(s, flags, size, p, _RET_IP_); 3609 3610 /* Clear memory outside IRQ disabled section */ 3611 if (unlikely(flags & __GFP_ZERO)) 3612 for (i = 0; i < size; i++) 3613 memset(p[i], 0, s->object_size); 3614 3615 slab_post_alloc_hook(s, flags, size, p); 3616 /* FIXME: Trace call missing. Christoph would like a bulk variant */ 3617 return size; 3618 error: 3619 local_irq_enable(); 3620 cache_alloc_debugcheck_after_bulk(s, flags, i, p, _RET_IP_); 3621 slab_post_alloc_hook(s, flags, i, p); 3622 __kmem_cache_free_bulk(s, i, p); 3623 return 0; 3624 } 3625 EXPORT_SYMBOL(kmem_cache_alloc_bulk); 3626 3627 #ifdef CONFIG_TRACING 3628 void * 3629 kmem_cache_alloc_trace(struct kmem_cache *cachep, gfp_t flags, size_t size) 3630 { 3631 void *ret; 3632 3633 ret = slab_alloc(cachep, flags, _RET_IP_); 3634 3635 kasan_kmalloc(cachep, ret, size, flags); 3636 trace_kmalloc(_RET_IP_, ret, 3637 size, cachep->size, flags); 3638 return ret; 3639 } 3640 EXPORT_SYMBOL(kmem_cache_alloc_trace); 3641 #endif 3642 3643 #ifdef CONFIG_NUMA 3644 /** 3645 * kmem_cache_alloc_node - Allocate an object on the specified node 3646 * @cachep: The cache to allocate from. 3647 * @flags: See kmalloc(). 3648 * @nodeid: node number of the target node. 3649 * 3650 * Identical to kmem_cache_alloc but it will allocate memory on the given 3651 * node, which can improve the performance for cpu bound structures. 3652 * 3653 * Fallback to other node is possible if __GFP_THISNODE is not set. 3654 */ 3655 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid) 3656 { 3657 void *ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); 3658 3659 kasan_slab_alloc(cachep, ret, flags); 3660 trace_kmem_cache_alloc_node(_RET_IP_, ret, 3661 cachep->object_size, cachep->size, 3662 flags, nodeid); 3663 3664 return ret; 3665 } 3666 EXPORT_SYMBOL(kmem_cache_alloc_node); 3667 3668 #ifdef CONFIG_TRACING 3669 void *kmem_cache_alloc_node_trace(struct kmem_cache *cachep, 3670 gfp_t flags, 3671 int nodeid, 3672 size_t size) 3673 { 3674 void *ret; 3675 3676 ret = slab_alloc_node(cachep, flags, nodeid, _RET_IP_); 3677 3678 kasan_kmalloc(cachep, ret, size, flags); 3679 trace_kmalloc_node(_RET_IP_, ret, 3680 size, cachep->size, 3681 flags, nodeid); 3682 return ret; 3683 } 3684 EXPORT_SYMBOL(kmem_cache_alloc_node_trace); 3685 #endif 3686 3687 static __always_inline void * 3688 __do_kmalloc_node(size_t size, gfp_t flags, int node, unsigned long caller) 3689 { 3690 struct kmem_cache *cachep; 3691 void *ret; 3692 3693 cachep = kmalloc_slab(size, flags); 3694 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3695 return cachep; 3696 ret = kmem_cache_alloc_node_trace(cachep, flags, node, size); 3697 kasan_kmalloc(cachep, ret, size, flags); 3698 3699 return ret; 3700 } 3701 3702 void *__kmalloc_node(size_t size, gfp_t flags, int node) 3703 { 3704 return __do_kmalloc_node(size, flags, node, _RET_IP_); 3705 } 3706 EXPORT_SYMBOL(__kmalloc_node); 3707 3708 void *__kmalloc_node_track_caller(size_t size, gfp_t flags, 3709 int node, unsigned long caller) 3710 { 3711 return __do_kmalloc_node(size, flags, node, caller); 3712 } 3713 EXPORT_SYMBOL(__kmalloc_node_track_caller); 3714 #endif /* CONFIG_NUMA */ 3715 3716 /** 3717 * __do_kmalloc - allocate memory 3718 * @size: how many bytes of memory are required. 3719 * @flags: the type of memory to allocate (see kmalloc). 3720 * @caller: function caller for debug tracking of the caller 3721 */ 3722 static __always_inline void *__do_kmalloc(size_t size, gfp_t flags, 3723 unsigned long caller) 3724 { 3725 struct kmem_cache *cachep; 3726 void *ret; 3727 3728 cachep = kmalloc_slab(size, flags); 3729 if (unlikely(ZERO_OR_NULL_PTR(cachep))) 3730 return cachep; 3731 ret = slab_alloc(cachep, flags, caller); 3732 3733 kasan_kmalloc(cachep, ret, size, flags); 3734 trace_kmalloc(caller, ret, 3735 size, cachep->size, flags); 3736 3737 return ret; 3738 } 3739 3740 void *__kmalloc(size_t size, gfp_t flags) 3741 { 3742 return __do_kmalloc(size, flags, _RET_IP_); 3743 } 3744 EXPORT_SYMBOL(__kmalloc); 3745 3746 void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller) 3747 { 3748 return __do_kmalloc(size, flags, caller); 3749 } 3750 EXPORT_SYMBOL(__kmalloc_track_caller); 3751 3752 /** 3753 * kmem_cache_free - Deallocate an object 3754 * @cachep: The cache the allocation was from. 3755 * @objp: The previously allocated object. 3756 * 3757 * Free an object which was previously allocated from this 3758 * cache. 3759 */ 3760 void kmem_cache_free(struct kmem_cache *cachep, void *objp) 3761 { 3762 unsigned long flags; 3763 cachep = cache_from_obj(cachep, objp); 3764 if (!cachep) 3765 return; 3766 3767 local_irq_save(flags); 3768 debug_check_no_locks_freed(objp, cachep->object_size); 3769 if (!(cachep->flags & SLAB_DEBUG_OBJECTS)) 3770 debug_check_no_obj_freed(objp, cachep->object_size); 3771 __cache_free(cachep, objp, _RET_IP_); 3772 local_irq_restore(flags); 3773 3774 trace_kmem_cache_free(_RET_IP_, objp); 3775 } 3776 EXPORT_SYMBOL(kmem_cache_free); 3777 3778 void kmem_cache_free_bulk(struct kmem_cache *orig_s, size_t size, void **p) 3779 { 3780 struct kmem_cache *s; 3781 size_t i; 3782 3783 local_irq_disable(); 3784 for (i = 0; i < size; i++) { 3785 void *objp = p[i]; 3786 3787 if (!orig_s) /* called via kfree_bulk */ 3788 s = virt_to_cache(objp); 3789 else 3790 s = cache_from_obj(orig_s, objp); 3791 3792 debug_check_no_locks_freed(objp, s->object_size); 3793 if (!(s->flags & SLAB_DEBUG_OBJECTS)) 3794 debug_check_no_obj_freed(objp, s->object_size); 3795 3796 __cache_free(s, objp, _RET_IP_); 3797 } 3798 local_irq_enable(); 3799 3800 /* FIXME: add tracing */ 3801 } 3802 EXPORT_SYMBOL(kmem_cache_free_bulk); 3803 3804 /** 3805 * kfree - free previously allocated memory 3806 * @objp: pointer returned by kmalloc. 3807 * 3808 * If @objp is NULL, no operation is performed. 3809 * 3810 * Don't free memory not originally allocated by kmalloc() 3811 * or you will run into trouble. 3812 */ 3813 void kfree(const void *objp) 3814 { 3815 struct kmem_cache *c; 3816 unsigned long flags; 3817 3818 trace_kfree(_RET_IP_, objp); 3819 3820 if (unlikely(ZERO_OR_NULL_PTR(objp))) 3821 return; 3822 local_irq_save(flags); 3823 kfree_debugcheck(objp); 3824 c = virt_to_cache(objp); 3825 debug_check_no_locks_freed(objp, c->object_size); 3826 3827 debug_check_no_obj_freed(objp, c->object_size); 3828 __cache_free(c, (void *)objp, _RET_IP_); 3829 local_irq_restore(flags); 3830 } 3831 EXPORT_SYMBOL(kfree); 3832 3833 /* 3834 * This initializes kmem_cache_node or resizes various caches for all nodes. 3835 */ 3836 static int setup_kmem_cache_nodes(struct kmem_cache *cachep, gfp_t gfp) 3837 { 3838 int ret; 3839 int node; 3840 struct kmem_cache_node *n; 3841 3842 for_each_online_node(node) { 3843 ret = setup_kmem_cache_node(cachep, node, gfp, true); 3844 if (ret) 3845 goto fail; 3846 3847 } 3848 3849 return 0; 3850 3851 fail: 3852 if (!cachep->list.next) { 3853 /* Cache is not active yet. Roll back what we did */ 3854 node--; 3855 while (node >= 0) { 3856 n = get_node(cachep, node); 3857 if (n) { 3858 kfree(n->shared); 3859 free_alien_cache(n->alien); 3860 kfree(n); 3861 cachep->node[node] = NULL; 3862 } 3863 node--; 3864 } 3865 } 3866 return -ENOMEM; 3867 } 3868 3869 /* Always called with the slab_mutex held */ 3870 static int __do_tune_cpucache(struct kmem_cache *cachep, int limit, 3871 int batchcount, int shared, gfp_t gfp) 3872 { 3873 struct array_cache __percpu *cpu_cache, *prev; 3874 int cpu; 3875 3876 cpu_cache = alloc_kmem_cache_cpus(cachep, limit, batchcount); 3877 if (!cpu_cache) 3878 return -ENOMEM; 3879 3880 prev = cachep->cpu_cache; 3881 cachep->cpu_cache = cpu_cache; 3882 kick_all_cpus_sync(); 3883 3884 check_irq_on(); 3885 cachep->batchcount = batchcount; 3886 cachep->limit = limit; 3887 cachep->shared = shared; 3888 3889 if (!prev) 3890 goto setup_node; 3891 3892 for_each_online_cpu(cpu) { 3893 LIST_HEAD(list); 3894 int node; 3895 struct kmem_cache_node *n; 3896 struct array_cache *ac = per_cpu_ptr(prev, cpu); 3897 3898 node = cpu_to_mem(cpu); 3899 n = get_node(cachep, node); 3900 spin_lock_irq(&n->list_lock); 3901 free_block(cachep, ac->entry, ac->avail, node, &list); 3902 spin_unlock_irq(&n->list_lock); 3903 slabs_destroy(cachep, &list); 3904 } 3905 free_percpu(prev); 3906 3907 setup_node: 3908 return setup_kmem_cache_nodes(cachep, gfp); 3909 } 3910 3911 static int do_tune_cpucache(struct kmem_cache *cachep, int limit, 3912 int batchcount, int shared, gfp_t gfp) 3913 { 3914 int ret; 3915 struct kmem_cache *c; 3916 3917 ret = __do_tune_cpucache(cachep, limit, batchcount, shared, gfp); 3918 3919 if (slab_state < FULL) 3920 return ret; 3921 3922 if ((ret < 0) || !is_root_cache(cachep)) 3923 return ret; 3924 3925 lockdep_assert_held(&slab_mutex); 3926 for_each_memcg_cache(c, cachep) { 3927 /* return value determined by the root cache only */ 3928 __do_tune_cpucache(c, limit, batchcount, shared, gfp); 3929 } 3930 3931 return ret; 3932 } 3933 3934 /* Called with slab_mutex held always */ 3935 static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp) 3936 { 3937 int err; 3938 int limit = 0; 3939 int shared = 0; 3940 int batchcount = 0; 3941 3942 err = cache_random_seq_create(cachep, cachep->num, gfp); 3943 if (err) 3944 goto end; 3945 3946 if (!is_root_cache(cachep)) { 3947 struct kmem_cache *root = memcg_root_cache(cachep); 3948 limit = root->limit; 3949 shared = root->shared; 3950 batchcount = root->batchcount; 3951 } 3952 3953 if (limit && shared && batchcount) 3954 goto skip_setup; 3955 /* 3956 * The head array serves three purposes: 3957 * - create a LIFO ordering, i.e. return objects that are cache-warm 3958 * - reduce the number of spinlock operations. 3959 * - reduce the number of linked list operations on the slab and 3960 * bufctl chains: array operations are cheaper. 3961 * The numbers are guessed, we should auto-tune as described by 3962 * Bonwick. 3963 */ 3964 if (cachep->size > 131072) 3965 limit = 1; 3966 else if (cachep->size > PAGE_SIZE) 3967 limit = 8; 3968 else if (cachep->size > 1024) 3969 limit = 24; 3970 else if (cachep->size > 256) 3971 limit = 54; 3972 else 3973 limit = 120; 3974 3975 /* 3976 * CPU bound tasks (e.g. network routing) can exhibit cpu bound 3977 * allocation behaviour: Most allocs on one cpu, most free operations 3978 * on another cpu. For these cases, an efficient object passing between 3979 * cpus is necessary. This is provided by a shared array. The array 3980 * replaces Bonwick's magazine layer. 3981 * On uniprocessor, it's functionally equivalent (but less efficient) 3982 * to a larger limit. Thus disabled by default. 3983 */ 3984 shared = 0; 3985 if (cachep->size <= PAGE_SIZE && num_possible_cpus() > 1) 3986 shared = 8; 3987 3988 #if DEBUG 3989 /* 3990 * With debugging enabled, large batchcount lead to excessively long 3991 * periods with disabled local interrupts. Limit the batchcount 3992 */ 3993 if (limit > 32) 3994 limit = 32; 3995 #endif 3996 batchcount = (limit + 1) / 2; 3997 skip_setup: 3998 err = do_tune_cpucache(cachep, limit, batchcount, shared, gfp); 3999 end: 4000 if (err) 4001 pr_err("enable_cpucache failed for %s, error %d\n", 4002 cachep->name, -err); 4003 return err; 4004 } 4005 4006 /* 4007 * Drain an array if it contains any elements taking the node lock only if 4008 * necessary. Note that the node listlock also protects the array_cache 4009 * if drain_array() is used on the shared array. 4010 */ 4011 static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n, 4012 struct array_cache *ac, int node) 4013 { 4014 LIST_HEAD(list); 4015 4016 /* ac from n->shared can be freed if we don't hold the slab_mutex. */ 4017 check_mutex_acquired(); 4018 4019 if (!ac || !ac->avail) 4020 return; 4021 4022 if (ac->touched) { 4023 ac->touched = 0; 4024 return; 4025 } 4026 4027 spin_lock_irq(&n->list_lock); 4028 drain_array_locked(cachep, ac, node, false, &list); 4029 spin_unlock_irq(&n->list_lock); 4030 4031 slabs_destroy(cachep, &list); 4032 } 4033 4034 /** 4035 * cache_reap - Reclaim memory from caches. 4036 * @w: work descriptor 4037 * 4038 * Called from workqueue/eventd every few seconds. 4039 * Purpose: 4040 * - clear the per-cpu caches for this CPU. 4041 * - return freeable pages to the main free memory pool. 4042 * 4043 * If we cannot acquire the cache chain mutex then just give up - we'll try 4044 * again on the next iteration. 4045 */ 4046 static void cache_reap(struct work_struct *w) 4047 { 4048 struct kmem_cache *searchp; 4049 struct kmem_cache_node *n; 4050 int node = numa_mem_id(); 4051 struct delayed_work *work = to_delayed_work(w); 4052 4053 if (!mutex_trylock(&slab_mutex)) 4054 /* Give up. Setup the next iteration. */ 4055 goto out; 4056 4057 list_for_each_entry(searchp, &slab_caches, list) { 4058 check_irq_on(); 4059 4060 /* 4061 * We only take the node lock if absolutely necessary and we 4062 * have established with reasonable certainty that 4063 * we can do some work if the lock was obtained. 4064 */ 4065 n = get_node(searchp, node); 4066 4067 reap_alien(searchp, n); 4068 4069 drain_array(searchp, n, cpu_cache_get(searchp), node); 4070 4071 /* 4072 * These are racy checks but it does not matter 4073 * if we skip one check or scan twice. 4074 */ 4075 if (time_after(n->next_reap, jiffies)) 4076 goto next; 4077 4078 n->next_reap = jiffies + REAPTIMEOUT_NODE; 4079 4080 drain_array(searchp, n, n->shared, node); 4081 4082 if (n->free_touched) 4083 n->free_touched = 0; 4084 else { 4085 int freed; 4086 4087 freed = drain_freelist(searchp, n, (n->free_limit + 4088 5 * searchp->num - 1) / (5 * searchp->num)); 4089 STATS_ADD_REAPED(searchp, freed); 4090 } 4091 next: 4092 cond_resched(); 4093 } 4094 check_irq_on(); 4095 mutex_unlock(&slab_mutex); 4096 next_reap_node(); 4097 out: 4098 /* Set up the next iteration */ 4099 schedule_delayed_work(work, round_jiffies_relative(REAPTIMEOUT_AC)); 4100 } 4101 4102 #ifdef CONFIG_SLABINFO 4103 void get_slabinfo(struct kmem_cache *cachep, struct slabinfo *sinfo) 4104 { 4105 struct page *page; 4106 unsigned long active_objs; 4107 unsigned long num_objs; 4108 unsigned long active_slabs = 0; 4109 unsigned long num_slabs, free_objects = 0, shared_avail = 0; 4110 unsigned long num_slabs_partial = 0, num_slabs_free = 0; 4111 unsigned long num_slabs_full = 0; 4112 const char *name; 4113 char *error = NULL; 4114 int node; 4115 struct kmem_cache_node *n; 4116 4117 active_objs = 0; 4118 num_slabs = 0; 4119 for_each_kmem_cache_node(cachep, node, n) { 4120 4121 check_irq_on(); 4122 spin_lock_irq(&n->list_lock); 4123 4124 num_slabs += n->num_slabs; 4125 4126 list_for_each_entry(page, &n->slabs_partial, lru) { 4127 if (page->active == cachep->num && !error) 4128 error = "slabs_partial accounting error"; 4129 if (!page->active && !error) 4130 error = "slabs_partial accounting error"; 4131 active_objs += page->active; 4132 num_slabs_partial++; 4133 } 4134 4135 list_for_each_entry(page, &n->slabs_free, lru) { 4136 if (page->active && !error) 4137 error = "slabs_free accounting error"; 4138 num_slabs_free++; 4139 } 4140 4141 free_objects += n->free_objects; 4142 if (n->shared) 4143 shared_avail += n->shared->avail; 4144 4145 spin_unlock_irq(&n->list_lock); 4146 } 4147 num_objs = num_slabs * cachep->num; 4148 active_slabs = num_slabs - num_slabs_free; 4149 num_slabs_full = num_slabs - (num_slabs_partial + num_slabs_free); 4150 active_objs += (num_slabs_full * cachep->num); 4151 4152 if (num_objs - active_objs != free_objects && !error) 4153 error = "free_objects accounting error"; 4154 4155 name = cachep->name; 4156 if (error) 4157 pr_err("slab: cache %s error: %s\n", name, error); 4158 4159 sinfo->active_objs = active_objs; 4160 sinfo->num_objs = num_objs; 4161 sinfo->active_slabs = active_slabs; 4162 sinfo->num_slabs = num_slabs; 4163 sinfo->shared_avail = shared_avail; 4164 sinfo->limit = cachep->limit; 4165 sinfo->batchcount = cachep->batchcount; 4166 sinfo->shared = cachep->shared; 4167 sinfo->objects_per_slab = cachep->num; 4168 sinfo->cache_order = cachep->gfporder; 4169 } 4170 4171 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *cachep) 4172 { 4173 #if STATS 4174 { /* node stats */ 4175 unsigned long high = cachep->high_mark; 4176 unsigned long allocs = cachep->num_allocations; 4177 unsigned long grown = cachep->grown; 4178 unsigned long reaped = cachep->reaped; 4179 unsigned long errors = cachep->errors; 4180 unsigned long max_freeable = cachep->max_freeable; 4181 unsigned long node_allocs = cachep->node_allocs; 4182 unsigned long node_frees = cachep->node_frees; 4183 unsigned long overflows = cachep->node_overflow; 4184 4185 seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu %4lu", 4186 allocs, high, grown, 4187 reaped, errors, max_freeable, node_allocs, 4188 node_frees, overflows); 4189 } 4190 /* cpu stats */ 4191 { 4192 unsigned long allochit = atomic_read(&cachep->allochit); 4193 unsigned long allocmiss = atomic_read(&cachep->allocmiss); 4194 unsigned long freehit = atomic_read(&cachep->freehit); 4195 unsigned long freemiss = atomic_read(&cachep->freemiss); 4196 4197 seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", 4198 allochit, allocmiss, freehit, freemiss); 4199 } 4200 #endif 4201 } 4202 4203 #define MAX_SLABINFO_WRITE 128 4204 /** 4205 * slabinfo_write - Tuning for the slab allocator 4206 * @file: unused 4207 * @buffer: user buffer 4208 * @count: data length 4209 * @ppos: unused 4210 */ 4211 ssize_t slabinfo_write(struct file *file, const char __user *buffer, 4212 size_t count, loff_t *ppos) 4213 { 4214 char kbuf[MAX_SLABINFO_WRITE + 1], *tmp; 4215 int limit, batchcount, shared, res; 4216 struct kmem_cache *cachep; 4217 4218 if (count > MAX_SLABINFO_WRITE) 4219 return -EINVAL; 4220 if (copy_from_user(&kbuf, buffer, count)) 4221 return -EFAULT; 4222 kbuf[MAX_SLABINFO_WRITE] = '\0'; 4223 4224 tmp = strchr(kbuf, ' '); 4225 if (!tmp) 4226 return -EINVAL; 4227 *tmp = '\0'; 4228 tmp++; 4229 if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) 4230 return -EINVAL; 4231 4232 /* Find the cache in the chain of caches. */ 4233 mutex_lock(&slab_mutex); 4234 res = -EINVAL; 4235 list_for_each_entry(cachep, &slab_caches, list) { 4236 if (!strcmp(cachep->name, kbuf)) { 4237 if (limit < 1 || batchcount < 1 || 4238 batchcount > limit || shared < 0) { 4239 res = 0; 4240 } else { 4241 res = do_tune_cpucache(cachep, limit, 4242 batchcount, shared, 4243 GFP_KERNEL); 4244 } 4245 break; 4246 } 4247 } 4248 mutex_unlock(&slab_mutex); 4249 if (res >= 0) 4250 res = count; 4251 return res; 4252 } 4253 4254 #ifdef CONFIG_DEBUG_SLAB_LEAK 4255 4256 static inline int add_caller(unsigned long *n, unsigned long v) 4257 { 4258 unsigned long *p; 4259 int l; 4260 if (!v) 4261 return 1; 4262 l = n[1]; 4263 p = n + 2; 4264 while (l) { 4265 int i = l/2; 4266 unsigned long *q = p + 2 * i; 4267 if (*q == v) { 4268 q[1]++; 4269 return 1; 4270 } 4271 if (*q > v) { 4272 l = i; 4273 } else { 4274 p = q + 2; 4275 l -= i + 1; 4276 } 4277 } 4278 if (++n[1] == n[0]) 4279 return 0; 4280 memmove(p + 2, p, n[1] * 2 * sizeof(unsigned long) - ((void *)p - (void *)n)); 4281 p[0] = v; 4282 p[1] = 1; 4283 return 1; 4284 } 4285 4286 static void handle_slab(unsigned long *n, struct kmem_cache *c, 4287 struct page *page) 4288 { 4289 void *p; 4290 int i, j; 4291 unsigned long v; 4292 4293 if (n[0] == n[1]) 4294 return; 4295 for (i = 0, p = page->s_mem; i < c->num; i++, p += c->size) { 4296 bool active = true; 4297 4298 for (j = page->active; j < c->num; j++) { 4299 if (get_free_obj(page, j) == i) { 4300 active = false; 4301 break; 4302 } 4303 } 4304 4305 if (!active) 4306 continue; 4307 4308 /* 4309 * probe_kernel_read() is used for DEBUG_PAGEALLOC. page table 4310 * mapping is established when actual object allocation and 4311 * we could mistakenly access the unmapped object in the cpu 4312 * cache. 4313 */ 4314 if (probe_kernel_read(&v, dbg_userword(c, p), sizeof(v))) 4315 continue; 4316 4317 if (!add_caller(n, v)) 4318 return; 4319 } 4320 } 4321 4322 static void show_symbol(struct seq_file *m, unsigned long address) 4323 { 4324 #ifdef CONFIG_KALLSYMS 4325 unsigned long offset, size; 4326 char modname[MODULE_NAME_LEN], name[KSYM_NAME_LEN]; 4327 4328 if (lookup_symbol_attrs(address, &size, &offset, modname, name) == 0) { 4329 seq_printf(m, "%s+%#lx/%#lx", name, offset, size); 4330 if (modname[0]) 4331 seq_printf(m, " [%s]", modname); 4332 return; 4333 } 4334 #endif 4335 seq_printf(m, "%p", (void *)address); 4336 } 4337 4338 static int leaks_show(struct seq_file *m, void *p) 4339 { 4340 struct kmem_cache *cachep = list_entry(p, struct kmem_cache, list); 4341 struct page *page; 4342 struct kmem_cache_node *n; 4343 const char *name; 4344 unsigned long *x = m->private; 4345 int node; 4346 int i; 4347 4348 if (!(cachep->flags & SLAB_STORE_USER)) 4349 return 0; 4350 if (!(cachep->flags & SLAB_RED_ZONE)) 4351 return 0; 4352 4353 /* 4354 * Set store_user_clean and start to grab stored user information 4355 * for all objects on this cache. If some alloc/free requests comes 4356 * during the processing, information would be wrong so restart 4357 * whole processing. 4358 */ 4359 do { 4360 set_store_user_clean(cachep); 4361 drain_cpu_caches(cachep); 4362 4363 x[1] = 0; 4364 4365 for_each_kmem_cache_node(cachep, node, n) { 4366 4367 check_irq_on(); 4368 spin_lock_irq(&n->list_lock); 4369 4370 list_for_each_entry(page, &n->slabs_full, lru) 4371 handle_slab(x, cachep, page); 4372 list_for_each_entry(page, &n->slabs_partial, lru) 4373 handle_slab(x, cachep, page); 4374 spin_unlock_irq(&n->list_lock); 4375 } 4376 } while (!is_store_user_clean(cachep)); 4377 4378 name = cachep->name; 4379 if (x[0] == x[1]) { 4380 /* Increase the buffer size */ 4381 mutex_unlock(&slab_mutex); 4382 m->private = kzalloc(x[0] * 4 * sizeof(unsigned long), GFP_KERNEL); 4383 if (!m->private) { 4384 /* Too bad, we are really out */ 4385 m->private = x; 4386 mutex_lock(&slab_mutex); 4387 return -ENOMEM; 4388 } 4389 *(unsigned long *)m->private = x[0] * 2; 4390 kfree(x); 4391 mutex_lock(&slab_mutex); 4392 /* Now make sure this entry will be retried */ 4393 m->count = m->size; 4394 return 0; 4395 } 4396 for (i = 0; i < x[1]; i++) { 4397 seq_printf(m, "%s: %lu ", name, x[2*i+3]); 4398 show_symbol(m, x[2*i+2]); 4399 seq_putc(m, '\n'); 4400 } 4401 4402 return 0; 4403 } 4404 4405 static const struct seq_operations slabstats_op = { 4406 .start = slab_start, 4407 .next = slab_next, 4408 .stop = slab_stop, 4409 .show = leaks_show, 4410 }; 4411 4412 static int slabstats_open(struct inode *inode, struct file *file) 4413 { 4414 unsigned long *n; 4415 4416 n = __seq_open_private(file, &slabstats_op, PAGE_SIZE); 4417 if (!n) 4418 return -ENOMEM; 4419 4420 *n = PAGE_SIZE / (2 * sizeof(unsigned long)); 4421 4422 return 0; 4423 } 4424 4425 static const struct file_operations proc_slabstats_operations = { 4426 .open = slabstats_open, 4427 .read = seq_read, 4428 .llseek = seq_lseek, 4429 .release = seq_release_private, 4430 }; 4431 #endif 4432 4433 static int __init slab_proc_init(void) 4434 { 4435 #ifdef CONFIG_DEBUG_SLAB_LEAK 4436 proc_create("slab_allocators", 0, NULL, &proc_slabstats_operations); 4437 #endif 4438 return 0; 4439 } 4440 module_init(slab_proc_init); 4441 #endif 4442 4443 #ifdef CONFIG_HARDENED_USERCOPY 4444 /* 4445 * Rejects objects that are incorrectly sized. 4446 * 4447 * Returns NULL if check passes, otherwise const char * to name of cache 4448 * to indicate an error. 4449 */ 4450 const char *__check_heap_object(const void *ptr, unsigned long n, 4451 struct page *page) 4452 { 4453 struct kmem_cache *cachep; 4454 unsigned int objnr; 4455 unsigned long offset; 4456 4457 /* Find and validate object. */ 4458 cachep = page->slab_cache; 4459 objnr = obj_to_index(cachep, page, (void *)ptr); 4460 BUG_ON(objnr >= cachep->num); 4461 4462 /* Find offset within object. */ 4463 offset = ptr - index_to_obj(cachep, page, objnr) - obj_offset(cachep); 4464 4465 /* Allow address range falling entirely within object size. */ 4466 if (offset <= cachep->object_size && n <= cachep->object_size - offset) 4467 return NULL; 4468 4469 return cachep->name; 4470 } 4471 #endif /* CONFIG_HARDENED_USERCOPY */ 4472 4473 /** 4474 * ksize - get the actual amount of memory allocated for a given object 4475 * @objp: Pointer to the object 4476 * 4477 * kmalloc may internally round up allocations and return more memory 4478 * than requested. ksize() can be used to determine the actual amount of 4479 * memory allocated. The caller may use this additional memory, even though 4480 * a smaller amount of memory was initially specified with the kmalloc call. 4481 * The caller must guarantee that objp points to a valid object previously 4482 * allocated with either kmalloc() or kmem_cache_alloc(). The object 4483 * must not be freed during the duration of the call. 4484 */ 4485 size_t ksize(const void *objp) 4486 { 4487 size_t size; 4488 4489 BUG_ON(!objp); 4490 if (unlikely(objp == ZERO_SIZE_PTR)) 4491 return 0; 4492 4493 size = virt_to_cache(objp)->object_size; 4494 /* We assume that ksize callers could use the whole allocated area, 4495 * so we need to unpoison this area. 4496 */ 4497 kasan_unpoison_shadow(objp, size); 4498 4499 return size; 4500 } 4501 EXPORT_SYMBOL(ksize); 4502