1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Slab allocator functions that are independent of the allocator strategy 4 * 5 * (C) 2012 Christoph Lameter <cl@linux.com> 6 */ 7 #include <linux/slab.h> 8 9 #include <linux/mm.h> 10 #include <linux/poison.h> 11 #include <linux/interrupt.h> 12 #include <linux/memory.h> 13 #include <linux/compiler.h> 14 #include <linux/module.h> 15 #include <linux/cpu.h> 16 #include <linux/uaccess.h> 17 #include <linux/seq_file.h> 18 #include <linux/proc_fs.h> 19 #include <asm/cacheflush.h> 20 #include <asm/tlbflush.h> 21 #include <asm/page.h> 22 #include <linux/memcontrol.h> 23 24 #define CREATE_TRACE_POINTS 25 #include <trace/events/kmem.h> 26 27 #include "slab.h" 28 29 enum slab_state slab_state; 30 LIST_HEAD(slab_caches); 31 DEFINE_MUTEX(slab_mutex); 32 struct kmem_cache *kmem_cache; 33 34 static LIST_HEAD(slab_caches_to_rcu_destroy); 35 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work); 36 static DECLARE_WORK(slab_caches_to_rcu_destroy_work, 37 slab_caches_to_rcu_destroy_workfn); 38 39 /* 40 * Set of flags that will prevent slab merging 41 */ 42 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 43 SLAB_TRACE | SLAB_TYPESAFE_BY_RCU | SLAB_NOLEAKTRACE | \ 44 SLAB_FAILSLAB | SLAB_KASAN) 45 46 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | \ 47 SLAB_ACCOUNT) 48 49 /* 50 * Merge control. If this is set then no merging of slab caches will occur. 51 */ 52 static bool slab_nomerge = !IS_ENABLED(CONFIG_SLAB_MERGE_DEFAULT); 53 54 static int __init setup_slab_nomerge(char *str) 55 { 56 slab_nomerge = true; 57 return 1; 58 } 59 60 #ifdef CONFIG_SLUB 61 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); 62 #endif 63 64 __setup("slab_nomerge", setup_slab_nomerge); 65 66 /* 67 * Determine the size of a slab object 68 */ 69 unsigned int kmem_cache_size(struct kmem_cache *s) 70 { 71 return s->object_size; 72 } 73 EXPORT_SYMBOL(kmem_cache_size); 74 75 #ifdef CONFIG_DEBUG_VM 76 static int kmem_cache_sanity_check(const char *name, size_t size) 77 { 78 struct kmem_cache *s = NULL; 79 80 if (!name || in_interrupt() || size < sizeof(void *) || 81 size > KMALLOC_MAX_SIZE) { 82 pr_err("kmem_cache_create(%s) integrity check failed\n", name); 83 return -EINVAL; 84 } 85 86 list_for_each_entry(s, &slab_caches, list) { 87 char tmp; 88 int res; 89 90 /* 91 * This happens when the module gets unloaded and doesn't 92 * destroy its slab cache and no-one else reuses the vmalloc 93 * area of the module. Print a warning. 94 */ 95 res = probe_kernel_address(s->name, tmp); 96 if (res) { 97 pr_err("Slab cache with size %d has lost its name\n", 98 s->object_size); 99 continue; 100 } 101 } 102 103 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 104 return 0; 105 } 106 #else 107 static inline int kmem_cache_sanity_check(const char *name, size_t size) 108 { 109 return 0; 110 } 111 #endif 112 113 void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p) 114 { 115 size_t i; 116 117 for (i = 0; i < nr; i++) { 118 if (s) 119 kmem_cache_free(s, p[i]); 120 else 121 kfree(p[i]); 122 } 123 } 124 125 int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, 126 void **p) 127 { 128 size_t i; 129 130 for (i = 0; i < nr; i++) { 131 void *x = p[i] = kmem_cache_alloc(s, flags); 132 if (!x) { 133 __kmem_cache_free_bulk(s, i, p); 134 return 0; 135 } 136 } 137 return i; 138 } 139 140 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB) 141 142 LIST_HEAD(slab_root_caches); 143 144 void slab_init_memcg_params(struct kmem_cache *s) 145 { 146 s->memcg_params.root_cache = NULL; 147 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL); 148 INIT_LIST_HEAD(&s->memcg_params.children); 149 } 150 151 static int init_memcg_params(struct kmem_cache *s, 152 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 153 { 154 struct memcg_cache_array *arr; 155 156 if (root_cache) { 157 s->memcg_params.root_cache = root_cache; 158 s->memcg_params.memcg = memcg; 159 INIT_LIST_HEAD(&s->memcg_params.children_node); 160 INIT_LIST_HEAD(&s->memcg_params.kmem_caches_node); 161 return 0; 162 } 163 164 slab_init_memcg_params(s); 165 166 if (!memcg_nr_cache_ids) 167 return 0; 168 169 arr = kvzalloc(sizeof(struct memcg_cache_array) + 170 memcg_nr_cache_ids * sizeof(void *), 171 GFP_KERNEL); 172 if (!arr) 173 return -ENOMEM; 174 175 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr); 176 return 0; 177 } 178 179 static void destroy_memcg_params(struct kmem_cache *s) 180 { 181 if (is_root_cache(s)) 182 kvfree(rcu_access_pointer(s->memcg_params.memcg_caches)); 183 } 184 185 static void free_memcg_params(struct rcu_head *rcu) 186 { 187 struct memcg_cache_array *old; 188 189 old = container_of(rcu, struct memcg_cache_array, rcu); 190 kvfree(old); 191 } 192 193 static int update_memcg_params(struct kmem_cache *s, int new_array_size) 194 { 195 struct memcg_cache_array *old, *new; 196 197 new = kvzalloc(sizeof(struct memcg_cache_array) + 198 new_array_size * sizeof(void *), GFP_KERNEL); 199 if (!new) 200 return -ENOMEM; 201 202 old = rcu_dereference_protected(s->memcg_params.memcg_caches, 203 lockdep_is_held(&slab_mutex)); 204 if (old) 205 memcpy(new->entries, old->entries, 206 memcg_nr_cache_ids * sizeof(void *)); 207 208 rcu_assign_pointer(s->memcg_params.memcg_caches, new); 209 if (old) 210 call_rcu(&old->rcu, free_memcg_params); 211 return 0; 212 } 213 214 int memcg_update_all_caches(int num_memcgs) 215 { 216 struct kmem_cache *s; 217 int ret = 0; 218 219 mutex_lock(&slab_mutex); 220 list_for_each_entry(s, &slab_root_caches, root_caches_node) { 221 ret = update_memcg_params(s, num_memcgs); 222 /* 223 * Instead of freeing the memory, we'll just leave the caches 224 * up to this point in an updated state. 225 */ 226 if (ret) 227 break; 228 } 229 mutex_unlock(&slab_mutex); 230 return ret; 231 } 232 233 void memcg_link_cache(struct kmem_cache *s) 234 { 235 if (is_root_cache(s)) { 236 list_add(&s->root_caches_node, &slab_root_caches); 237 } else { 238 list_add(&s->memcg_params.children_node, 239 &s->memcg_params.root_cache->memcg_params.children); 240 list_add(&s->memcg_params.kmem_caches_node, 241 &s->memcg_params.memcg->kmem_caches); 242 } 243 } 244 245 static void memcg_unlink_cache(struct kmem_cache *s) 246 { 247 if (is_root_cache(s)) { 248 list_del(&s->root_caches_node); 249 } else { 250 list_del(&s->memcg_params.children_node); 251 list_del(&s->memcg_params.kmem_caches_node); 252 } 253 } 254 #else 255 static inline int init_memcg_params(struct kmem_cache *s, 256 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 257 { 258 return 0; 259 } 260 261 static inline void destroy_memcg_params(struct kmem_cache *s) 262 { 263 } 264 265 static inline void memcg_unlink_cache(struct kmem_cache *s) 266 { 267 } 268 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */ 269 270 /* 271 * Figure out what the alignment of the objects will be given a set of 272 * flags, a user specified alignment and the size of the objects. 273 */ 274 static unsigned long calculate_alignment(unsigned long flags, 275 unsigned long align, unsigned long size) 276 { 277 /* 278 * If the user wants hardware cache aligned objects then follow that 279 * suggestion if the object is sufficiently large. 280 * 281 * The hardware cache alignment cannot override the specified 282 * alignment though. If that is greater then use it. 283 */ 284 if (flags & SLAB_HWCACHE_ALIGN) { 285 unsigned long ralign; 286 287 ralign = cache_line_size(); 288 while (size <= ralign / 2) 289 ralign /= 2; 290 align = max(align, ralign); 291 } 292 293 if (align < ARCH_SLAB_MINALIGN) 294 align = ARCH_SLAB_MINALIGN; 295 296 return ALIGN(align, sizeof(void *)); 297 } 298 299 /* 300 * Find a mergeable slab cache 301 */ 302 int slab_unmergeable(struct kmem_cache *s) 303 { 304 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) 305 return 1; 306 307 if (!is_root_cache(s)) 308 return 1; 309 310 if (s->ctor) 311 return 1; 312 313 /* 314 * We may have set a slab to be unmergeable during bootstrap. 315 */ 316 if (s->refcount < 0) 317 return 1; 318 319 return 0; 320 } 321 322 struct kmem_cache *find_mergeable(size_t size, size_t align, 323 slab_flags_t flags, const char *name, void (*ctor)(void *)) 324 { 325 struct kmem_cache *s; 326 327 if (slab_nomerge) 328 return NULL; 329 330 if (ctor) 331 return NULL; 332 333 size = ALIGN(size, sizeof(void *)); 334 align = calculate_alignment(flags, align, size); 335 size = ALIGN(size, align); 336 flags = kmem_cache_flags(size, flags, name, NULL); 337 338 if (flags & SLAB_NEVER_MERGE) 339 return NULL; 340 341 list_for_each_entry_reverse(s, &slab_root_caches, root_caches_node) { 342 if (slab_unmergeable(s)) 343 continue; 344 345 if (size > s->size) 346 continue; 347 348 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) 349 continue; 350 /* 351 * Check if alignment is compatible. 352 * Courtesy of Adrian Drzewiecki 353 */ 354 if ((s->size & ~(align - 1)) != s->size) 355 continue; 356 357 if (s->size - size >= sizeof(void *)) 358 continue; 359 360 if (IS_ENABLED(CONFIG_SLAB) && align && 361 (align > s->align || s->align % align)) 362 continue; 363 364 return s; 365 } 366 return NULL; 367 } 368 369 static struct kmem_cache *create_cache(const char *name, 370 size_t object_size, size_t size, size_t align, 371 slab_flags_t flags, void (*ctor)(void *), 372 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 373 { 374 struct kmem_cache *s; 375 int err; 376 377 err = -ENOMEM; 378 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); 379 if (!s) 380 goto out; 381 382 s->name = name; 383 s->object_size = object_size; 384 s->size = size; 385 s->align = align; 386 s->ctor = ctor; 387 388 err = init_memcg_params(s, memcg, root_cache); 389 if (err) 390 goto out_free_cache; 391 392 err = __kmem_cache_create(s, flags); 393 if (err) 394 goto out_free_cache; 395 396 s->refcount = 1; 397 list_add(&s->list, &slab_caches); 398 memcg_link_cache(s); 399 out: 400 if (err) 401 return ERR_PTR(err); 402 return s; 403 404 out_free_cache: 405 destroy_memcg_params(s); 406 kmem_cache_free(kmem_cache, s); 407 goto out; 408 } 409 410 /* 411 * kmem_cache_create - Create a cache. 412 * @name: A string which is used in /proc/slabinfo to identify this cache. 413 * @size: The size of objects to be created in this cache. 414 * @align: The required alignment for the objects. 415 * @flags: SLAB flags 416 * @ctor: A constructor for the objects. 417 * 418 * Returns a ptr to the cache on success, NULL on failure. 419 * Cannot be called within a interrupt, but can be interrupted. 420 * The @ctor is run when new pages are allocated by the cache. 421 * 422 * The flags are 423 * 424 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 425 * to catch references to uninitialised memory. 426 * 427 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 428 * for buffer overruns. 429 * 430 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 431 * cacheline. This can be beneficial if you're counting cycles as closely 432 * as davem. 433 */ 434 struct kmem_cache * 435 kmem_cache_create(const char *name, size_t size, size_t align, 436 slab_flags_t flags, void (*ctor)(void *)) 437 { 438 struct kmem_cache *s = NULL; 439 const char *cache_name; 440 int err; 441 442 get_online_cpus(); 443 get_online_mems(); 444 memcg_get_cache_ids(); 445 446 mutex_lock(&slab_mutex); 447 448 err = kmem_cache_sanity_check(name, size); 449 if (err) { 450 goto out_unlock; 451 } 452 453 /* Refuse requests with allocator specific flags */ 454 if (flags & ~SLAB_FLAGS_PERMITTED) { 455 err = -EINVAL; 456 goto out_unlock; 457 } 458 459 /* 460 * Some allocators will constraint the set of valid flags to a subset 461 * of all flags. We expect them to define CACHE_CREATE_MASK in this 462 * case, and we'll just provide them with a sanitized version of the 463 * passed flags. 464 */ 465 flags &= CACHE_CREATE_MASK; 466 467 s = __kmem_cache_alias(name, size, align, flags, ctor); 468 if (s) 469 goto out_unlock; 470 471 cache_name = kstrdup_const(name, GFP_KERNEL); 472 if (!cache_name) { 473 err = -ENOMEM; 474 goto out_unlock; 475 } 476 477 s = create_cache(cache_name, size, size, 478 calculate_alignment(flags, align, size), 479 flags, ctor, NULL, NULL); 480 if (IS_ERR(s)) { 481 err = PTR_ERR(s); 482 kfree_const(cache_name); 483 } 484 485 out_unlock: 486 mutex_unlock(&slab_mutex); 487 488 memcg_put_cache_ids(); 489 put_online_mems(); 490 put_online_cpus(); 491 492 if (err) { 493 if (flags & SLAB_PANIC) 494 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", 495 name, err); 496 else { 497 pr_warn("kmem_cache_create(%s) failed with error %d\n", 498 name, err); 499 dump_stack(); 500 } 501 return NULL; 502 } 503 return s; 504 } 505 EXPORT_SYMBOL(kmem_cache_create); 506 507 static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work) 508 { 509 LIST_HEAD(to_destroy); 510 struct kmem_cache *s, *s2; 511 512 /* 513 * On destruction, SLAB_TYPESAFE_BY_RCU kmem_caches are put on the 514 * @slab_caches_to_rcu_destroy list. The slab pages are freed 515 * through RCU and and the associated kmem_cache are dereferenced 516 * while freeing the pages, so the kmem_caches should be freed only 517 * after the pending RCU operations are finished. As rcu_barrier() 518 * is a pretty slow operation, we batch all pending destructions 519 * asynchronously. 520 */ 521 mutex_lock(&slab_mutex); 522 list_splice_init(&slab_caches_to_rcu_destroy, &to_destroy); 523 mutex_unlock(&slab_mutex); 524 525 if (list_empty(&to_destroy)) 526 return; 527 528 rcu_barrier(); 529 530 list_for_each_entry_safe(s, s2, &to_destroy, list) { 531 #ifdef SLAB_SUPPORTS_SYSFS 532 sysfs_slab_release(s); 533 #else 534 slab_kmem_cache_release(s); 535 #endif 536 } 537 } 538 539 static int shutdown_cache(struct kmem_cache *s) 540 { 541 /* free asan quarantined objects */ 542 kasan_cache_shutdown(s); 543 544 if (__kmem_cache_shutdown(s) != 0) 545 return -EBUSY; 546 547 memcg_unlink_cache(s); 548 list_del(&s->list); 549 550 if (s->flags & SLAB_TYPESAFE_BY_RCU) { 551 list_add_tail(&s->list, &slab_caches_to_rcu_destroy); 552 schedule_work(&slab_caches_to_rcu_destroy_work); 553 } else { 554 #ifdef SLAB_SUPPORTS_SYSFS 555 sysfs_slab_release(s); 556 #else 557 slab_kmem_cache_release(s); 558 #endif 559 } 560 561 return 0; 562 } 563 564 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB) 565 /* 566 * memcg_create_kmem_cache - Create a cache for a memory cgroup. 567 * @memcg: The memory cgroup the new cache is for. 568 * @root_cache: The parent of the new cache. 569 * 570 * This function attempts to create a kmem cache that will serve allocation 571 * requests going from @memcg to @root_cache. The new cache inherits properties 572 * from its parent. 573 */ 574 void memcg_create_kmem_cache(struct mem_cgroup *memcg, 575 struct kmem_cache *root_cache) 576 { 577 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */ 578 struct cgroup_subsys_state *css = &memcg->css; 579 struct memcg_cache_array *arr; 580 struct kmem_cache *s = NULL; 581 char *cache_name; 582 int idx; 583 584 get_online_cpus(); 585 get_online_mems(); 586 587 mutex_lock(&slab_mutex); 588 589 /* 590 * The memory cgroup could have been offlined while the cache 591 * creation work was pending. 592 */ 593 if (memcg->kmem_state != KMEM_ONLINE) 594 goto out_unlock; 595 596 idx = memcg_cache_id(memcg); 597 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches, 598 lockdep_is_held(&slab_mutex)); 599 600 /* 601 * Since per-memcg caches are created asynchronously on first 602 * allocation (see memcg_kmem_get_cache()), several threads can try to 603 * create the same cache, but only one of them may succeed. 604 */ 605 if (arr->entries[idx]) 606 goto out_unlock; 607 608 cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf)); 609 cache_name = kasprintf(GFP_KERNEL, "%s(%llu:%s)", root_cache->name, 610 css->serial_nr, memcg_name_buf); 611 if (!cache_name) 612 goto out_unlock; 613 614 s = create_cache(cache_name, root_cache->object_size, 615 root_cache->size, root_cache->align, 616 root_cache->flags & CACHE_CREATE_MASK, 617 root_cache->ctor, memcg, root_cache); 618 /* 619 * If we could not create a memcg cache, do not complain, because 620 * that's not critical at all as we can always proceed with the root 621 * cache. 622 */ 623 if (IS_ERR(s)) { 624 kfree(cache_name); 625 goto out_unlock; 626 } 627 628 /* 629 * Since readers won't lock (see cache_from_memcg_idx()), we need a 630 * barrier here to ensure nobody will see the kmem_cache partially 631 * initialized. 632 */ 633 smp_wmb(); 634 arr->entries[idx] = s; 635 636 out_unlock: 637 mutex_unlock(&slab_mutex); 638 639 put_online_mems(); 640 put_online_cpus(); 641 } 642 643 static void kmemcg_deactivate_workfn(struct work_struct *work) 644 { 645 struct kmem_cache *s = container_of(work, struct kmem_cache, 646 memcg_params.deact_work); 647 648 get_online_cpus(); 649 get_online_mems(); 650 651 mutex_lock(&slab_mutex); 652 653 s->memcg_params.deact_fn(s); 654 655 mutex_unlock(&slab_mutex); 656 657 put_online_mems(); 658 put_online_cpus(); 659 660 /* done, put the ref from slab_deactivate_memcg_cache_rcu_sched() */ 661 css_put(&s->memcg_params.memcg->css); 662 } 663 664 static void kmemcg_deactivate_rcufn(struct rcu_head *head) 665 { 666 struct kmem_cache *s = container_of(head, struct kmem_cache, 667 memcg_params.deact_rcu_head); 668 669 /* 670 * We need to grab blocking locks. Bounce to ->deact_work. The 671 * work item shares the space with the RCU head and can't be 672 * initialized eariler. 673 */ 674 INIT_WORK(&s->memcg_params.deact_work, kmemcg_deactivate_workfn); 675 queue_work(memcg_kmem_cache_wq, &s->memcg_params.deact_work); 676 } 677 678 /** 679 * slab_deactivate_memcg_cache_rcu_sched - schedule deactivation after a 680 * sched RCU grace period 681 * @s: target kmem_cache 682 * @deact_fn: deactivation function to call 683 * 684 * Schedule @deact_fn to be invoked with online cpus, mems and slab_mutex 685 * held after a sched RCU grace period. The slab is guaranteed to stay 686 * alive until @deact_fn is finished. This is to be used from 687 * __kmemcg_cache_deactivate(). 688 */ 689 void slab_deactivate_memcg_cache_rcu_sched(struct kmem_cache *s, 690 void (*deact_fn)(struct kmem_cache *)) 691 { 692 if (WARN_ON_ONCE(is_root_cache(s)) || 693 WARN_ON_ONCE(s->memcg_params.deact_fn)) 694 return; 695 696 /* pin memcg so that @s doesn't get destroyed in the middle */ 697 css_get(&s->memcg_params.memcg->css); 698 699 s->memcg_params.deact_fn = deact_fn; 700 call_rcu_sched(&s->memcg_params.deact_rcu_head, kmemcg_deactivate_rcufn); 701 } 702 703 void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) 704 { 705 int idx; 706 struct memcg_cache_array *arr; 707 struct kmem_cache *s, *c; 708 709 idx = memcg_cache_id(memcg); 710 711 get_online_cpus(); 712 get_online_mems(); 713 714 mutex_lock(&slab_mutex); 715 list_for_each_entry(s, &slab_root_caches, root_caches_node) { 716 arr = rcu_dereference_protected(s->memcg_params.memcg_caches, 717 lockdep_is_held(&slab_mutex)); 718 c = arr->entries[idx]; 719 if (!c) 720 continue; 721 722 __kmemcg_cache_deactivate(c); 723 arr->entries[idx] = NULL; 724 } 725 mutex_unlock(&slab_mutex); 726 727 put_online_mems(); 728 put_online_cpus(); 729 } 730 731 void memcg_destroy_kmem_caches(struct mem_cgroup *memcg) 732 { 733 struct kmem_cache *s, *s2; 734 735 get_online_cpus(); 736 get_online_mems(); 737 738 mutex_lock(&slab_mutex); 739 list_for_each_entry_safe(s, s2, &memcg->kmem_caches, 740 memcg_params.kmem_caches_node) { 741 /* 742 * The cgroup is about to be freed and therefore has no charges 743 * left. Hence, all its caches must be empty by now. 744 */ 745 BUG_ON(shutdown_cache(s)); 746 } 747 mutex_unlock(&slab_mutex); 748 749 put_online_mems(); 750 put_online_cpus(); 751 } 752 753 static int shutdown_memcg_caches(struct kmem_cache *s) 754 { 755 struct memcg_cache_array *arr; 756 struct kmem_cache *c, *c2; 757 LIST_HEAD(busy); 758 int i; 759 760 BUG_ON(!is_root_cache(s)); 761 762 /* 763 * First, shutdown active caches, i.e. caches that belong to online 764 * memory cgroups. 765 */ 766 arr = rcu_dereference_protected(s->memcg_params.memcg_caches, 767 lockdep_is_held(&slab_mutex)); 768 for_each_memcg_cache_index(i) { 769 c = arr->entries[i]; 770 if (!c) 771 continue; 772 if (shutdown_cache(c)) 773 /* 774 * The cache still has objects. Move it to a temporary 775 * list so as not to try to destroy it for a second 776 * time while iterating over inactive caches below. 777 */ 778 list_move(&c->memcg_params.children_node, &busy); 779 else 780 /* 781 * The cache is empty and will be destroyed soon. Clear 782 * the pointer to it in the memcg_caches array so that 783 * it will never be accessed even if the root cache 784 * stays alive. 785 */ 786 arr->entries[i] = NULL; 787 } 788 789 /* 790 * Second, shutdown all caches left from memory cgroups that are now 791 * offline. 792 */ 793 list_for_each_entry_safe(c, c2, &s->memcg_params.children, 794 memcg_params.children_node) 795 shutdown_cache(c); 796 797 list_splice(&busy, &s->memcg_params.children); 798 799 /* 800 * A cache being destroyed must be empty. In particular, this means 801 * that all per memcg caches attached to it must be empty too. 802 */ 803 if (!list_empty(&s->memcg_params.children)) 804 return -EBUSY; 805 return 0; 806 } 807 #else 808 static inline int shutdown_memcg_caches(struct kmem_cache *s) 809 { 810 return 0; 811 } 812 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */ 813 814 void slab_kmem_cache_release(struct kmem_cache *s) 815 { 816 __kmem_cache_release(s); 817 destroy_memcg_params(s); 818 kfree_const(s->name); 819 kmem_cache_free(kmem_cache, s); 820 } 821 822 void kmem_cache_destroy(struct kmem_cache *s) 823 { 824 int err; 825 826 if (unlikely(!s)) 827 return; 828 829 get_online_cpus(); 830 get_online_mems(); 831 832 mutex_lock(&slab_mutex); 833 834 s->refcount--; 835 if (s->refcount) 836 goto out_unlock; 837 838 err = shutdown_memcg_caches(s); 839 if (!err) 840 err = shutdown_cache(s); 841 842 if (err) { 843 pr_err("kmem_cache_destroy %s: Slab cache still has objects\n", 844 s->name); 845 dump_stack(); 846 } 847 out_unlock: 848 mutex_unlock(&slab_mutex); 849 850 put_online_mems(); 851 put_online_cpus(); 852 } 853 EXPORT_SYMBOL(kmem_cache_destroy); 854 855 /** 856 * kmem_cache_shrink - Shrink a cache. 857 * @cachep: The cache to shrink. 858 * 859 * Releases as many slabs as possible for a cache. 860 * To help debugging, a zero exit status indicates all slabs were released. 861 */ 862 int kmem_cache_shrink(struct kmem_cache *cachep) 863 { 864 int ret; 865 866 get_online_cpus(); 867 get_online_mems(); 868 kasan_cache_shrink(cachep); 869 ret = __kmem_cache_shrink(cachep); 870 put_online_mems(); 871 put_online_cpus(); 872 return ret; 873 } 874 EXPORT_SYMBOL(kmem_cache_shrink); 875 876 bool slab_is_available(void) 877 { 878 return slab_state >= UP; 879 } 880 881 #ifndef CONFIG_SLOB 882 /* Create a cache during boot when no slab services are available yet */ 883 void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size, 884 slab_flags_t flags) 885 { 886 int err; 887 888 s->name = name; 889 s->size = s->object_size = size; 890 s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); 891 892 slab_init_memcg_params(s); 893 894 err = __kmem_cache_create(s, flags); 895 896 if (err) 897 panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n", 898 name, size, err); 899 900 s->refcount = -1; /* Exempt from merging for now */ 901 } 902 903 struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size, 904 slab_flags_t flags) 905 { 906 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 907 908 if (!s) 909 panic("Out of memory when creating slab %s\n", name); 910 911 create_boot_cache(s, name, size, flags); 912 list_add(&s->list, &slab_caches); 913 memcg_link_cache(s); 914 s->refcount = 1; 915 return s; 916 } 917 918 struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; 919 EXPORT_SYMBOL(kmalloc_caches); 920 921 #ifdef CONFIG_ZONE_DMA 922 struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1]; 923 EXPORT_SYMBOL(kmalloc_dma_caches); 924 #endif 925 926 /* 927 * Conversion table for small slabs sizes / 8 to the index in the 928 * kmalloc array. This is necessary for slabs < 192 since we have non power 929 * of two cache sizes there. The size of larger slabs can be determined using 930 * fls. 931 */ 932 static s8 size_index[24] = { 933 3, /* 8 */ 934 4, /* 16 */ 935 5, /* 24 */ 936 5, /* 32 */ 937 6, /* 40 */ 938 6, /* 48 */ 939 6, /* 56 */ 940 6, /* 64 */ 941 1, /* 72 */ 942 1, /* 80 */ 943 1, /* 88 */ 944 1, /* 96 */ 945 7, /* 104 */ 946 7, /* 112 */ 947 7, /* 120 */ 948 7, /* 128 */ 949 2, /* 136 */ 950 2, /* 144 */ 951 2, /* 152 */ 952 2, /* 160 */ 953 2, /* 168 */ 954 2, /* 176 */ 955 2, /* 184 */ 956 2 /* 192 */ 957 }; 958 959 static inline int size_index_elem(size_t bytes) 960 { 961 return (bytes - 1) / 8; 962 } 963 964 /* 965 * Find the kmem_cache structure that serves a given size of 966 * allocation 967 */ 968 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) 969 { 970 int index; 971 972 if (unlikely(size > KMALLOC_MAX_SIZE)) { 973 WARN_ON_ONCE(!(flags & __GFP_NOWARN)); 974 return NULL; 975 } 976 977 if (size <= 192) { 978 if (!size) 979 return ZERO_SIZE_PTR; 980 981 index = size_index[size_index_elem(size)]; 982 } else 983 index = fls(size - 1); 984 985 #ifdef CONFIG_ZONE_DMA 986 if (unlikely((flags & GFP_DMA))) 987 return kmalloc_dma_caches[index]; 988 989 #endif 990 return kmalloc_caches[index]; 991 } 992 993 /* 994 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 995 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is 996 * kmalloc-67108864. 997 */ 998 const struct kmalloc_info_struct kmalloc_info[] __initconst = { 999 {NULL, 0}, {"kmalloc-96", 96}, 1000 {"kmalloc-192", 192}, {"kmalloc-8", 8}, 1001 {"kmalloc-16", 16}, {"kmalloc-32", 32}, 1002 {"kmalloc-64", 64}, {"kmalloc-128", 128}, 1003 {"kmalloc-256", 256}, {"kmalloc-512", 512}, 1004 {"kmalloc-1024", 1024}, {"kmalloc-2048", 2048}, 1005 {"kmalloc-4096", 4096}, {"kmalloc-8192", 8192}, 1006 {"kmalloc-16384", 16384}, {"kmalloc-32768", 32768}, 1007 {"kmalloc-65536", 65536}, {"kmalloc-131072", 131072}, 1008 {"kmalloc-262144", 262144}, {"kmalloc-524288", 524288}, 1009 {"kmalloc-1048576", 1048576}, {"kmalloc-2097152", 2097152}, 1010 {"kmalloc-4194304", 4194304}, {"kmalloc-8388608", 8388608}, 1011 {"kmalloc-16777216", 16777216}, {"kmalloc-33554432", 33554432}, 1012 {"kmalloc-67108864", 67108864} 1013 }; 1014 1015 /* 1016 * Patch up the size_index table if we have strange large alignment 1017 * requirements for the kmalloc array. This is only the case for 1018 * MIPS it seems. The standard arches will not generate any code here. 1019 * 1020 * Largest permitted alignment is 256 bytes due to the way we 1021 * handle the index determination for the smaller caches. 1022 * 1023 * Make sure that nothing crazy happens if someone starts tinkering 1024 * around with ARCH_KMALLOC_MINALIGN 1025 */ 1026 void __init setup_kmalloc_cache_index_table(void) 1027 { 1028 int i; 1029 1030 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 1031 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); 1032 1033 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 1034 int elem = size_index_elem(i); 1035 1036 if (elem >= ARRAY_SIZE(size_index)) 1037 break; 1038 size_index[elem] = KMALLOC_SHIFT_LOW; 1039 } 1040 1041 if (KMALLOC_MIN_SIZE >= 64) { 1042 /* 1043 * The 96 byte size cache is not used if the alignment 1044 * is 64 byte. 1045 */ 1046 for (i = 64 + 8; i <= 96; i += 8) 1047 size_index[size_index_elem(i)] = 7; 1048 1049 } 1050 1051 if (KMALLOC_MIN_SIZE >= 128) { 1052 /* 1053 * The 192 byte sized cache is not used if the alignment 1054 * is 128 byte. Redirect kmalloc to use the 256 byte cache 1055 * instead. 1056 */ 1057 for (i = 128 + 8; i <= 192; i += 8) 1058 size_index[size_index_elem(i)] = 8; 1059 } 1060 } 1061 1062 static void __init new_kmalloc_cache(int idx, slab_flags_t flags) 1063 { 1064 kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name, 1065 kmalloc_info[idx].size, flags); 1066 } 1067 1068 /* 1069 * Create the kmalloc array. Some of the regular kmalloc arrays 1070 * may already have been created because they were needed to 1071 * enable allocations for slab creation. 1072 */ 1073 void __init create_kmalloc_caches(slab_flags_t flags) 1074 { 1075 int i; 1076 1077 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 1078 if (!kmalloc_caches[i]) 1079 new_kmalloc_cache(i, flags); 1080 1081 /* 1082 * Caches that are not of the two-to-the-power-of size. 1083 * These have to be created immediately after the 1084 * earlier power of two caches 1085 */ 1086 if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) 1087 new_kmalloc_cache(1, flags); 1088 if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) 1089 new_kmalloc_cache(2, flags); 1090 } 1091 1092 /* Kmalloc array is now usable */ 1093 slab_state = UP; 1094 1095 #ifdef CONFIG_ZONE_DMA 1096 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { 1097 struct kmem_cache *s = kmalloc_caches[i]; 1098 1099 if (s) { 1100 int size = kmalloc_size(i); 1101 char *n = kasprintf(GFP_NOWAIT, 1102 "dma-kmalloc-%d", size); 1103 1104 BUG_ON(!n); 1105 kmalloc_dma_caches[i] = create_kmalloc_cache(n, 1106 size, SLAB_CACHE_DMA | flags); 1107 } 1108 } 1109 #endif 1110 } 1111 #endif /* !CONFIG_SLOB */ 1112 1113 /* 1114 * To avoid unnecessary overhead, we pass through large allocation requests 1115 * directly to the page allocator. We use __GFP_COMP, because we will need to 1116 * know the allocation order to free the pages properly in kfree. 1117 */ 1118 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) 1119 { 1120 void *ret; 1121 struct page *page; 1122 1123 flags |= __GFP_COMP; 1124 page = alloc_pages(flags, order); 1125 ret = page ? page_address(page) : NULL; 1126 kmemleak_alloc(ret, size, 1, flags); 1127 kasan_kmalloc_large(ret, size, flags); 1128 return ret; 1129 } 1130 EXPORT_SYMBOL(kmalloc_order); 1131 1132 #ifdef CONFIG_TRACING 1133 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) 1134 { 1135 void *ret = kmalloc_order(size, flags, order); 1136 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); 1137 return ret; 1138 } 1139 EXPORT_SYMBOL(kmalloc_order_trace); 1140 #endif 1141 1142 #ifdef CONFIG_SLAB_FREELIST_RANDOM 1143 /* Randomize a generic freelist */ 1144 static void freelist_randomize(struct rnd_state *state, unsigned int *list, 1145 size_t count) 1146 { 1147 size_t i; 1148 unsigned int rand; 1149 1150 for (i = 0; i < count; i++) 1151 list[i] = i; 1152 1153 /* Fisher-Yates shuffle */ 1154 for (i = count - 1; i > 0; i--) { 1155 rand = prandom_u32_state(state); 1156 rand %= (i + 1); 1157 swap(list[i], list[rand]); 1158 } 1159 } 1160 1161 /* Create a random sequence per cache */ 1162 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 1163 gfp_t gfp) 1164 { 1165 struct rnd_state state; 1166 1167 if (count < 2 || cachep->random_seq) 1168 return 0; 1169 1170 cachep->random_seq = kcalloc(count, sizeof(unsigned int), gfp); 1171 if (!cachep->random_seq) 1172 return -ENOMEM; 1173 1174 /* Get best entropy at this stage of boot */ 1175 prandom_seed_state(&state, get_random_long()); 1176 1177 freelist_randomize(&state, cachep->random_seq, count); 1178 return 0; 1179 } 1180 1181 /* Destroy the per-cache random freelist sequence */ 1182 void cache_random_seq_destroy(struct kmem_cache *cachep) 1183 { 1184 kfree(cachep->random_seq); 1185 cachep->random_seq = NULL; 1186 } 1187 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 1188 1189 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 1190 #ifdef CONFIG_SLAB 1191 #define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR) 1192 #else 1193 #define SLABINFO_RIGHTS S_IRUSR 1194 #endif 1195 1196 static void print_slabinfo_header(struct seq_file *m) 1197 { 1198 /* 1199 * Output format version, so at least we can change it 1200 * without _too_ many complaints. 1201 */ 1202 #ifdef CONFIG_DEBUG_SLAB 1203 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 1204 #else 1205 seq_puts(m, "slabinfo - version: 2.1\n"); 1206 #endif 1207 seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); 1208 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 1209 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 1210 #ifdef CONFIG_DEBUG_SLAB 1211 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> <error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 1212 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 1213 #endif 1214 seq_putc(m, '\n'); 1215 } 1216 1217 void *slab_start(struct seq_file *m, loff_t *pos) 1218 { 1219 mutex_lock(&slab_mutex); 1220 return seq_list_start(&slab_root_caches, *pos); 1221 } 1222 1223 void *slab_next(struct seq_file *m, void *p, loff_t *pos) 1224 { 1225 return seq_list_next(p, &slab_root_caches, pos); 1226 } 1227 1228 void slab_stop(struct seq_file *m, void *p) 1229 { 1230 mutex_unlock(&slab_mutex); 1231 } 1232 1233 static void 1234 memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) 1235 { 1236 struct kmem_cache *c; 1237 struct slabinfo sinfo; 1238 1239 if (!is_root_cache(s)) 1240 return; 1241 1242 for_each_memcg_cache(c, s) { 1243 memset(&sinfo, 0, sizeof(sinfo)); 1244 get_slabinfo(c, &sinfo); 1245 1246 info->active_slabs += sinfo.active_slabs; 1247 info->num_slabs += sinfo.num_slabs; 1248 info->shared_avail += sinfo.shared_avail; 1249 info->active_objs += sinfo.active_objs; 1250 info->num_objs += sinfo.num_objs; 1251 } 1252 } 1253 1254 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1255 { 1256 struct slabinfo sinfo; 1257 1258 memset(&sinfo, 0, sizeof(sinfo)); 1259 get_slabinfo(s, &sinfo); 1260 1261 memcg_accumulate_slabinfo(s, &sinfo); 1262 1263 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1264 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, 1265 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1266 1267 seq_printf(m, " : tunables %4u %4u %4u", 1268 sinfo.limit, sinfo.batchcount, sinfo.shared); 1269 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1270 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1271 slabinfo_show_stats(m, s); 1272 seq_putc(m, '\n'); 1273 } 1274 1275 static int slab_show(struct seq_file *m, void *p) 1276 { 1277 struct kmem_cache *s = list_entry(p, struct kmem_cache, root_caches_node); 1278 1279 if (p == slab_root_caches.next) 1280 print_slabinfo_header(m); 1281 cache_show(s, m); 1282 return 0; 1283 } 1284 1285 void dump_unreclaimable_slab(void) 1286 { 1287 struct kmem_cache *s, *s2; 1288 struct slabinfo sinfo; 1289 1290 /* 1291 * Here acquiring slab_mutex is risky since we don't prefer to get 1292 * sleep in oom path. But, without mutex hold, it may introduce a 1293 * risk of crash. 1294 * Use mutex_trylock to protect the list traverse, dump nothing 1295 * without acquiring the mutex. 1296 */ 1297 if (!mutex_trylock(&slab_mutex)) { 1298 pr_warn("excessive unreclaimable slab but cannot dump stats\n"); 1299 return; 1300 } 1301 1302 pr_info("Unreclaimable slab info:\n"); 1303 pr_info("Name Used Total\n"); 1304 1305 list_for_each_entry_safe(s, s2, &slab_caches, list) { 1306 if (!is_root_cache(s) || (s->flags & SLAB_RECLAIM_ACCOUNT)) 1307 continue; 1308 1309 get_slabinfo(s, &sinfo); 1310 1311 if (sinfo.num_objs > 0) 1312 pr_info("%-17s %10luKB %10luKB\n", cache_name(s), 1313 (sinfo.active_objs * s->size) / 1024, 1314 (sinfo.num_objs * s->size) / 1024); 1315 } 1316 mutex_unlock(&slab_mutex); 1317 } 1318 1319 #if defined(CONFIG_MEMCG) 1320 void *memcg_slab_start(struct seq_file *m, loff_t *pos) 1321 { 1322 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1323 1324 mutex_lock(&slab_mutex); 1325 return seq_list_start(&memcg->kmem_caches, *pos); 1326 } 1327 1328 void *memcg_slab_next(struct seq_file *m, void *p, loff_t *pos) 1329 { 1330 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1331 1332 return seq_list_next(p, &memcg->kmem_caches, pos); 1333 } 1334 1335 void memcg_slab_stop(struct seq_file *m, void *p) 1336 { 1337 mutex_unlock(&slab_mutex); 1338 } 1339 1340 int memcg_slab_show(struct seq_file *m, void *p) 1341 { 1342 struct kmem_cache *s = list_entry(p, struct kmem_cache, 1343 memcg_params.kmem_caches_node); 1344 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1345 1346 if (p == memcg->kmem_caches.next) 1347 print_slabinfo_header(m); 1348 cache_show(s, m); 1349 return 0; 1350 } 1351 #endif 1352 1353 /* 1354 * slabinfo_op - iterator that generates /proc/slabinfo 1355 * 1356 * Output layout: 1357 * cache-name 1358 * num-active-objs 1359 * total-objs 1360 * object size 1361 * num-active-slabs 1362 * total-slabs 1363 * num-pages-per-slab 1364 * + further values on SMP and with statistics enabled 1365 */ 1366 static const struct seq_operations slabinfo_op = { 1367 .start = slab_start, 1368 .next = slab_next, 1369 .stop = slab_stop, 1370 .show = slab_show, 1371 }; 1372 1373 static int slabinfo_open(struct inode *inode, struct file *file) 1374 { 1375 return seq_open(file, &slabinfo_op); 1376 } 1377 1378 static const struct file_operations proc_slabinfo_operations = { 1379 .open = slabinfo_open, 1380 .read = seq_read, 1381 .write = slabinfo_write, 1382 .llseek = seq_lseek, 1383 .release = seq_release, 1384 }; 1385 1386 static int __init slab_proc_init(void) 1387 { 1388 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, 1389 &proc_slabinfo_operations); 1390 return 0; 1391 } 1392 module_init(slab_proc_init); 1393 #endif /* CONFIG_SLAB || CONFIG_SLUB_DEBUG */ 1394 1395 static __always_inline void *__do_krealloc(const void *p, size_t new_size, 1396 gfp_t flags) 1397 { 1398 void *ret; 1399 size_t ks = 0; 1400 1401 if (p) 1402 ks = ksize(p); 1403 1404 if (ks >= new_size) { 1405 kasan_krealloc((void *)p, new_size, flags); 1406 return (void *)p; 1407 } 1408 1409 ret = kmalloc_track_caller(new_size, flags); 1410 if (ret && p) 1411 memcpy(ret, p, ks); 1412 1413 return ret; 1414 } 1415 1416 /** 1417 * __krealloc - like krealloc() but don't free @p. 1418 * @p: object to reallocate memory for. 1419 * @new_size: how many bytes of memory are required. 1420 * @flags: the type of memory to allocate. 1421 * 1422 * This function is like krealloc() except it never frees the originally 1423 * allocated buffer. Use this if you don't want to free the buffer immediately 1424 * like, for example, with RCU. 1425 */ 1426 void *__krealloc(const void *p, size_t new_size, gfp_t flags) 1427 { 1428 if (unlikely(!new_size)) 1429 return ZERO_SIZE_PTR; 1430 1431 return __do_krealloc(p, new_size, flags); 1432 1433 } 1434 EXPORT_SYMBOL(__krealloc); 1435 1436 /** 1437 * krealloc - reallocate memory. The contents will remain unchanged. 1438 * @p: object to reallocate memory for. 1439 * @new_size: how many bytes of memory are required. 1440 * @flags: the type of memory to allocate. 1441 * 1442 * The contents of the object pointed to are preserved up to the 1443 * lesser of the new and old sizes. If @p is %NULL, krealloc() 1444 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a 1445 * %NULL pointer, the object pointed to is freed. 1446 */ 1447 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1448 { 1449 void *ret; 1450 1451 if (unlikely(!new_size)) { 1452 kfree(p); 1453 return ZERO_SIZE_PTR; 1454 } 1455 1456 ret = __do_krealloc(p, new_size, flags); 1457 if (ret && p != ret) 1458 kfree(p); 1459 1460 return ret; 1461 } 1462 EXPORT_SYMBOL(krealloc); 1463 1464 /** 1465 * kzfree - like kfree but zero memory 1466 * @p: object to free memory of 1467 * 1468 * The memory of the object @p points to is zeroed before freed. 1469 * If @p is %NULL, kzfree() does nothing. 1470 * 1471 * Note: this function zeroes the whole allocated buffer which can be a good 1472 * deal bigger than the requested buffer size passed to kmalloc(). So be 1473 * careful when using this function in performance sensitive code. 1474 */ 1475 void kzfree(const void *p) 1476 { 1477 size_t ks; 1478 void *mem = (void *)p; 1479 1480 if (unlikely(ZERO_OR_NULL_PTR(mem))) 1481 return; 1482 ks = ksize(mem); 1483 memset(mem, 0, ks); 1484 kfree(mem); 1485 } 1486 EXPORT_SYMBOL(kzfree); 1487 1488 /* Tracepoints definitions. */ 1489 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1490 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1491 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); 1492 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); 1493 EXPORT_TRACEPOINT_SYMBOL(kfree); 1494 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1495