1 /* 2 * Slab allocator functions that are independent of the allocator strategy 3 * 4 * (C) 2012 Christoph Lameter <cl@linux.com> 5 */ 6 #include <linux/slab.h> 7 8 #include <linux/mm.h> 9 #include <linux/poison.h> 10 #include <linux/interrupt.h> 11 #include <linux/memory.h> 12 #include <linux/compiler.h> 13 #include <linux/module.h> 14 #include <linux/cpu.h> 15 #include <linux/uaccess.h> 16 #include <linux/seq_file.h> 17 #include <linux/proc_fs.h> 18 #include <asm/cacheflush.h> 19 #include <asm/tlbflush.h> 20 #include <asm/page.h> 21 #include <linux/memcontrol.h> 22 23 #define CREATE_TRACE_POINTS 24 #include <trace/events/kmem.h> 25 26 #include "slab.h" 27 28 enum slab_state slab_state; 29 LIST_HEAD(slab_caches); 30 DEFINE_MUTEX(slab_mutex); 31 struct kmem_cache *kmem_cache; 32 33 /* 34 * Set of flags that will prevent slab merging 35 */ 36 #define SLAB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 37 SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \ 38 SLAB_FAILSLAB) 39 40 #define SLAB_MERGE_SAME (SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA | SLAB_NOTRACK) 41 42 /* 43 * Merge control. If this is set then no merging of slab caches will occur. 44 * (Could be removed. This was introduced to pacify the merge skeptics.) 45 */ 46 static int slab_nomerge; 47 48 static int __init setup_slab_nomerge(char *str) 49 { 50 slab_nomerge = 1; 51 return 1; 52 } 53 54 #ifdef CONFIG_SLUB 55 __setup_param("slub_nomerge", slub_nomerge, setup_slab_nomerge, 0); 56 #endif 57 58 __setup("slab_nomerge", setup_slab_nomerge); 59 60 /* 61 * Determine the size of a slab object 62 */ 63 unsigned int kmem_cache_size(struct kmem_cache *s) 64 { 65 return s->object_size; 66 } 67 EXPORT_SYMBOL(kmem_cache_size); 68 69 #ifdef CONFIG_DEBUG_VM 70 static int kmem_cache_sanity_check(const char *name, size_t size) 71 { 72 struct kmem_cache *s = NULL; 73 74 if (!name || in_interrupt() || size < sizeof(void *) || 75 size > KMALLOC_MAX_SIZE) { 76 pr_err("kmem_cache_create(%s) integrity check failed\n", name); 77 return -EINVAL; 78 } 79 80 list_for_each_entry(s, &slab_caches, list) { 81 char tmp; 82 int res; 83 84 /* 85 * This happens when the module gets unloaded and doesn't 86 * destroy its slab cache and no-one else reuses the vmalloc 87 * area of the module. Print a warning. 88 */ 89 res = probe_kernel_address(s->name, tmp); 90 if (res) { 91 pr_err("Slab cache with size %d has lost its name\n", 92 s->object_size); 93 continue; 94 } 95 } 96 97 WARN_ON(strchr(name, ' ')); /* It confuses parsers */ 98 return 0; 99 } 100 #else 101 static inline int kmem_cache_sanity_check(const char *name, size_t size) 102 { 103 return 0; 104 } 105 #endif 106 107 #ifdef CONFIG_MEMCG_KMEM 108 void slab_init_memcg_params(struct kmem_cache *s) 109 { 110 s->memcg_params.is_root_cache = true; 111 INIT_LIST_HEAD(&s->memcg_params.list); 112 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL); 113 } 114 115 static int init_memcg_params(struct kmem_cache *s, 116 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 117 { 118 struct memcg_cache_array *arr; 119 120 if (memcg) { 121 s->memcg_params.is_root_cache = false; 122 s->memcg_params.memcg = memcg; 123 s->memcg_params.root_cache = root_cache; 124 return 0; 125 } 126 127 slab_init_memcg_params(s); 128 129 if (!memcg_nr_cache_ids) 130 return 0; 131 132 arr = kzalloc(sizeof(struct memcg_cache_array) + 133 memcg_nr_cache_ids * sizeof(void *), 134 GFP_KERNEL); 135 if (!arr) 136 return -ENOMEM; 137 138 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr); 139 return 0; 140 } 141 142 static void destroy_memcg_params(struct kmem_cache *s) 143 { 144 if (is_root_cache(s)) 145 kfree(rcu_access_pointer(s->memcg_params.memcg_caches)); 146 } 147 148 static int update_memcg_params(struct kmem_cache *s, int new_array_size) 149 { 150 struct memcg_cache_array *old, *new; 151 152 if (!is_root_cache(s)) 153 return 0; 154 155 new = kzalloc(sizeof(struct memcg_cache_array) + 156 new_array_size * sizeof(void *), GFP_KERNEL); 157 if (!new) 158 return -ENOMEM; 159 160 old = rcu_dereference_protected(s->memcg_params.memcg_caches, 161 lockdep_is_held(&slab_mutex)); 162 if (old) 163 memcpy(new->entries, old->entries, 164 memcg_nr_cache_ids * sizeof(void *)); 165 166 rcu_assign_pointer(s->memcg_params.memcg_caches, new); 167 if (old) 168 kfree_rcu(old, rcu); 169 return 0; 170 } 171 172 int memcg_update_all_caches(int num_memcgs) 173 { 174 struct kmem_cache *s; 175 int ret = 0; 176 177 mutex_lock(&slab_mutex); 178 list_for_each_entry(s, &slab_caches, list) { 179 ret = update_memcg_params(s, num_memcgs); 180 /* 181 * Instead of freeing the memory, we'll just leave the caches 182 * up to this point in an updated state. 183 */ 184 if (ret) 185 break; 186 } 187 mutex_unlock(&slab_mutex); 188 return ret; 189 } 190 #else 191 static inline int init_memcg_params(struct kmem_cache *s, 192 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 193 { 194 return 0; 195 } 196 197 static inline void destroy_memcg_params(struct kmem_cache *s) 198 { 199 } 200 #endif /* CONFIG_MEMCG_KMEM */ 201 202 /* 203 * Find a mergeable slab cache 204 */ 205 int slab_unmergeable(struct kmem_cache *s) 206 { 207 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) 208 return 1; 209 210 if (!is_root_cache(s)) 211 return 1; 212 213 if (s->ctor) 214 return 1; 215 216 /* 217 * We may have set a slab to be unmergeable during bootstrap. 218 */ 219 if (s->refcount < 0) 220 return 1; 221 222 return 0; 223 } 224 225 struct kmem_cache *find_mergeable(size_t size, size_t align, 226 unsigned long flags, const char *name, void (*ctor)(void *)) 227 { 228 struct kmem_cache *s; 229 230 if (slab_nomerge || (flags & SLAB_NEVER_MERGE)) 231 return NULL; 232 233 if (ctor) 234 return NULL; 235 236 size = ALIGN(size, sizeof(void *)); 237 align = calculate_alignment(flags, align, size); 238 size = ALIGN(size, align); 239 flags = kmem_cache_flags(size, flags, name, NULL); 240 241 list_for_each_entry_reverse(s, &slab_caches, list) { 242 if (slab_unmergeable(s)) 243 continue; 244 245 if (size > s->size) 246 continue; 247 248 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) 249 continue; 250 /* 251 * Check if alignment is compatible. 252 * Courtesy of Adrian Drzewiecki 253 */ 254 if ((s->size & ~(align - 1)) != s->size) 255 continue; 256 257 if (s->size - size >= sizeof(void *)) 258 continue; 259 260 if (IS_ENABLED(CONFIG_SLAB) && align && 261 (align > s->align || s->align % align)) 262 continue; 263 264 return s; 265 } 266 return NULL; 267 } 268 269 /* 270 * Figure out what the alignment of the objects will be given a set of 271 * flags, a user specified alignment and the size of the objects. 272 */ 273 unsigned long calculate_alignment(unsigned long flags, 274 unsigned long align, unsigned long size) 275 { 276 /* 277 * If the user wants hardware cache aligned objects then follow that 278 * suggestion if the object is sufficiently large. 279 * 280 * The hardware cache alignment cannot override the specified 281 * alignment though. If that is greater then use it. 282 */ 283 if (flags & SLAB_HWCACHE_ALIGN) { 284 unsigned long ralign = cache_line_size(); 285 while (size <= ralign / 2) 286 ralign /= 2; 287 align = max(align, ralign); 288 } 289 290 if (align < ARCH_SLAB_MINALIGN) 291 align = ARCH_SLAB_MINALIGN; 292 293 return ALIGN(align, sizeof(void *)); 294 } 295 296 static struct kmem_cache * 297 do_kmem_cache_create(const char *name, size_t object_size, size_t size, 298 size_t align, unsigned long flags, void (*ctor)(void *), 299 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 300 { 301 struct kmem_cache *s; 302 int err; 303 304 err = -ENOMEM; 305 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); 306 if (!s) 307 goto out; 308 309 s->name = name; 310 s->object_size = object_size; 311 s->size = size; 312 s->align = align; 313 s->ctor = ctor; 314 315 err = init_memcg_params(s, memcg, root_cache); 316 if (err) 317 goto out_free_cache; 318 319 err = __kmem_cache_create(s, flags); 320 if (err) 321 goto out_free_cache; 322 323 s->refcount = 1; 324 list_add(&s->list, &slab_caches); 325 out: 326 if (err) 327 return ERR_PTR(err); 328 return s; 329 330 out_free_cache: 331 destroy_memcg_params(s); 332 kmem_cache_free(kmem_cache, s); 333 goto out; 334 } 335 336 /* 337 * kmem_cache_create - Create a cache. 338 * @name: A string which is used in /proc/slabinfo to identify this cache. 339 * @size: The size of objects to be created in this cache. 340 * @align: The required alignment for the objects. 341 * @flags: SLAB flags 342 * @ctor: A constructor for the objects. 343 * 344 * Returns a ptr to the cache on success, NULL on failure. 345 * Cannot be called within a interrupt, but can be interrupted. 346 * The @ctor is run when new pages are allocated by the cache. 347 * 348 * The flags are 349 * 350 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 351 * to catch references to uninitialised memory. 352 * 353 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 354 * for buffer overruns. 355 * 356 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 357 * cacheline. This can be beneficial if you're counting cycles as closely 358 * as davem. 359 */ 360 struct kmem_cache * 361 kmem_cache_create(const char *name, size_t size, size_t align, 362 unsigned long flags, void (*ctor)(void *)) 363 { 364 struct kmem_cache *s; 365 const char *cache_name; 366 int err; 367 368 get_online_cpus(); 369 get_online_mems(); 370 memcg_get_cache_ids(); 371 372 mutex_lock(&slab_mutex); 373 374 err = kmem_cache_sanity_check(name, size); 375 if (err) { 376 s = NULL; /* suppress uninit var warning */ 377 goto out_unlock; 378 } 379 380 /* 381 * Some allocators will constraint the set of valid flags to a subset 382 * of all flags. We expect them to define CACHE_CREATE_MASK in this 383 * case, and we'll just provide them with a sanitized version of the 384 * passed flags. 385 */ 386 flags &= CACHE_CREATE_MASK; 387 388 s = __kmem_cache_alias(name, size, align, flags, ctor); 389 if (s) 390 goto out_unlock; 391 392 cache_name = kstrdup_const(name, GFP_KERNEL); 393 if (!cache_name) { 394 err = -ENOMEM; 395 goto out_unlock; 396 } 397 398 s = do_kmem_cache_create(cache_name, size, size, 399 calculate_alignment(flags, align, size), 400 flags, ctor, NULL, NULL); 401 if (IS_ERR(s)) { 402 err = PTR_ERR(s); 403 kfree_const(cache_name); 404 } 405 406 out_unlock: 407 mutex_unlock(&slab_mutex); 408 409 memcg_put_cache_ids(); 410 put_online_mems(); 411 put_online_cpus(); 412 413 if (err) { 414 if (flags & SLAB_PANIC) 415 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", 416 name, err); 417 else { 418 printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d", 419 name, err); 420 dump_stack(); 421 } 422 return NULL; 423 } 424 return s; 425 } 426 EXPORT_SYMBOL(kmem_cache_create); 427 428 static int do_kmem_cache_shutdown(struct kmem_cache *s, 429 struct list_head *release, bool *need_rcu_barrier) 430 { 431 if (__kmem_cache_shutdown(s) != 0) { 432 printk(KERN_ERR "kmem_cache_destroy %s: " 433 "Slab cache still has objects\n", s->name); 434 dump_stack(); 435 return -EBUSY; 436 } 437 438 if (s->flags & SLAB_DESTROY_BY_RCU) 439 *need_rcu_barrier = true; 440 441 #ifdef CONFIG_MEMCG_KMEM 442 if (!is_root_cache(s)) 443 list_del(&s->memcg_params.list); 444 #endif 445 list_move(&s->list, release); 446 return 0; 447 } 448 449 static void do_kmem_cache_release(struct list_head *release, 450 bool need_rcu_barrier) 451 { 452 struct kmem_cache *s, *s2; 453 454 if (need_rcu_barrier) 455 rcu_barrier(); 456 457 list_for_each_entry_safe(s, s2, release, list) { 458 #ifdef SLAB_SUPPORTS_SYSFS 459 sysfs_slab_remove(s); 460 #else 461 slab_kmem_cache_release(s); 462 #endif 463 } 464 } 465 466 #ifdef CONFIG_MEMCG_KMEM 467 /* 468 * memcg_create_kmem_cache - Create a cache for a memory cgroup. 469 * @memcg: The memory cgroup the new cache is for. 470 * @root_cache: The parent of the new cache. 471 * 472 * This function attempts to create a kmem cache that will serve allocation 473 * requests going from @memcg to @root_cache. The new cache inherits properties 474 * from its parent. 475 */ 476 void memcg_create_kmem_cache(struct mem_cgroup *memcg, 477 struct kmem_cache *root_cache) 478 { 479 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */ 480 struct cgroup_subsys_state *css = mem_cgroup_css(memcg); 481 struct memcg_cache_array *arr; 482 struct kmem_cache *s = NULL; 483 char *cache_name; 484 int idx; 485 486 get_online_cpus(); 487 get_online_mems(); 488 489 mutex_lock(&slab_mutex); 490 491 /* 492 * The memory cgroup could have been deactivated while the cache 493 * creation work was pending. 494 */ 495 if (!memcg_kmem_is_active(memcg)) 496 goto out_unlock; 497 498 idx = memcg_cache_id(memcg); 499 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches, 500 lockdep_is_held(&slab_mutex)); 501 502 /* 503 * Since per-memcg caches are created asynchronously on first 504 * allocation (see memcg_kmem_get_cache()), several threads can try to 505 * create the same cache, but only one of them may succeed. 506 */ 507 if (arr->entries[idx]) 508 goto out_unlock; 509 510 cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf)); 511 cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, 512 css->id, memcg_name_buf); 513 if (!cache_name) 514 goto out_unlock; 515 516 s = do_kmem_cache_create(cache_name, root_cache->object_size, 517 root_cache->size, root_cache->align, 518 root_cache->flags, root_cache->ctor, 519 memcg, root_cache); 520 /* 521 * If we could not create a memcg cache, do not complain, because 522 * that's not critical at all as we can always proceed with the root 523 * cache. 524 */ 525 if (IS_ERR(s)) { 526 kfree(cache_name); 527 goto out_unlock; 528 } 529 530 list_add(&s->memcg_params.list, &root_cache->memcg_params.list); 531 532 /* 533 * Since readers won't lock (see cache_from_memcg_idx()), we need a 534 * barrier here to ensure nobody will see the kmem_cache partially 535 * initialized. 536 */ 537 smp_wmb(); 538 arr->entries[idx] = s; 539 540 out_unlock: 541 mutex_unlock(&slab_mutex); 542 543 put_online_mems(); 544 put_online_cpus(); 545 } 546 547 void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) 548 { 549 int idx; 550 struct memcg_cache_array *arr; 551 struct kmem_cache *s, *c; 552 553 idx = memcg_cache_id(memcg); 554 555 get_online_cpus(); 556 get_online_mems(); 557 558 mutex_lock(&slab_mutex); 559 list_for_each_entry(s, &slab_caches, list) { 560 if (!is_root_cache(s)) 561 continue; 562 563 arr = rcu_dereference_protected(s->memcg_params.memcg_caches, 564 lockdep_is_held(&slab_mutex)); 565 c = arr->entries[idx]; 566 if (!c) 567 continue; 568 569 __kmem_cache_shrink(c, true); 570 arr->entries[idx] = NULL; 571 } 572 mutex_unlock(&slab_mutex); 573 574 put_online_mems(); 575 put_online_cpus(); 576 } 577 578 void memcg_destroy_kmem_caches(struct mem_cgroup *memcg) 579 { 580 LIST_HEAD(release); 581 bool need_rcu_barrier = false; 582 struct kmem_cache *s, *s2; 583 584 get_online_cpus(); 585 get_online_mems(); 586 587 mutex_lock(&slab_mutex); 588 list_for_each_entry_safe(s, s2, &slab_caches, list) { 589 if (is_root_cache(s) || s->memcg_params.memcg != memcg) 590 continue; 591 /* 592 * The cgroup is about to be freed and therefore has no charges 593 * left. Hence, all its caches must be empty by now. 594 */ 595 BUG_ON(do_kmem_cache_shutdown(s, &release, &need_rcu_barrier)); 596 } 597 mutex_unlock(&slab_mutex); 598 599 put_online_mems(); 600 put_online_cpus(); 601 602 do_kmem_cache_release(&release, need_rcu_barrier); 603 } 604 #endif /* CONFIG_MEMCG_KMEM */ 605 606 void slab_kmem_cache_release(struct kmem_cache *s) 607 { 608 destroy_memcg_params(s); 609 kfree_const(s->name); 610 kmem_cache_free(kmem_cache, s); 611 } 612 613 void kmem_cache_destroy(struct kmem_cache *s) 614 { 615 struct kmem_cache *c, *c2; 616 LIST_HEAD(release); 617 bool need_rcu_barrier = false; 618 bool busy = false; 619 620 BUG_ON(!is_root_cache(s)); 621 622 get_online_cpus(); 623 get_online_mems(); 624 625 mutex_lock(&slab_mutex); 626 627 s->refcount--; 628 if (s->refcount) 629 goto out_unlock; 630 631 for_each_memcg_cache_safe(c, c2, s) { 632 if (do_kmem_cache_shutdown(c, &release, &need_rcu_barrier)) 633 busy = true; 634 } 635 636 if (!busy) 637 do_kmem_cache_shutdown(s, &release, &need_rcu_barrier); 638 639 out_unlock: 640 mutex_unlock(&slab_mutex); 641 642 put_online_mems(); 643 put_online_cpus(); 644 645 do_kmem_cache_release(&release, need_rcu_barrier); 646 } 647 EXPORT_SYMBOL(kmem_cache_destroy); 648 649 /** 650 * kmem_cache_shrink - Shrink a cache. 651 * @cachep: The cache to shrink. 652 * 653 * Releases as many slabs as possible for a cache. 654 * To help debugging, a zero exit status indicates all slabs were released. 655 */ 656 int kmem_cache_shrink(struct kmem_cache *cachep) 657 { 658 int ret; 659 660 get_online_cpus(); 661 get_online_mems(); 662 ret = __kmem_cache_shrink(cachep, false); 663 put_online_mems(); 664 put_online_cpus(); 665 return ret; 666 } 667 EXPORT_SYMBOL(kmem_cache_shrink); 668 669 int slab_is_available(void) 670 { 671 return slab_state >= UP; 672 } 673 674 #ifndef CONFIG_SLOB 675 /* Create a cache during boot when no slab services are available yet */ 676 void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size, 677 unsigned long flags) 678 { 679 int err; 680 681 s->name = name; 682 s->size = s->object_size = size; 683 s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); 684 685 slab_init_memcg_params(s); 686 687 err = __kmem_cache_create(s, flags); 688 689 if (err) 690 panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n", 691 name, size, err); 692 693 s->refcount = -1; /* Exempt from merging for now */ 694 } 695 696 struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size, 697 unsigned long flags) 698 { 699 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 700 701 if (!s) 702 panic("Out of memory when creating slab %s\n", name); 703 704 create_boot_cache(s, name, size, flags); 705 list_add(&s->list, &slab_caches); 706 s->refcount = 1; 707 return s; 708 } 709 710 struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; 711 EXPORT_SYMBOL(kmalloc_caches); 712 713 #ifdef CONFIG_ZONE_DMA 714 struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1]; 715 EXPORT_SYMBOL(kmalloc_dma_caches); 716 #endif 717 718 /* 719 * Conversion table for small slabs sizes / 8 to the index in the 720 * kmalloc array. This is necessary for slabs < 192 since we have non power 721 * of two cache sizes there. The size of larger slabs can be determined using 722 * fls. 723 */ 724 static s8 size_index[24] = { 725 3, /* 8 */ 726 4, /* 16 */ 727 5, /* 24 */ 728 5, /* 32 */ 729 6, /* 40 */ 730 6, /* 48 */ 731 6, /* 56 */ 732 6, /* 64 */ 733 1, /* 72 */ 734 1, /* 80 */ 735 1, /* 88 */ 736 1, /* 96 */ 737 7, /* 104 */ 738 7, /* 112 */ 739 7, /* 120 */ 740 7, /* 128 */ 741 2, /* 136 */ 742 2, /* 144 */ 743 2, /* 152 */ 744 2, /* 160 */ 745 2, /* 168 */ 746 2, /* 176 */ 747 2, /* 184 */ 748 2 /* 192 */ 749 }; 750 751 static inline int size_index_elem(size_t bytes) 752 { 753 return (bytes - 1) / 8; 754 } 755 756 /* 757 * Find the kmem_cache structure that serves a given size of 758 * allocation 759 */ 760 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) 761 { 762 int index; 763 764 if (unlikely(size > KMALLOC_MAX_SIZE)) { 765 WARN_ON_ONCE(!(flags & __GFP_NOWARN)); 766 return NULL; 767 } 768 769 if (size <= 192) { 770 if (!size) 771 return ZERO_SIZE_PTR; 772 773 index = size_index[size_index_elem(size)]; 774 } else 775 index = fls(size - 1); 776 777 #ifdef CONFIG_ZONE_DMA 778 if (unlikely((flags & GFP_DMA))) 779 return kmalloc_dma_caches[index]; 780 781 #endif 782 return kmalloc_caches[index]; 783 } 784 785 /* 786 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 787 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is 788 * kmalloc-67108864. 789 */ 790 static struct { 791 const char *name; 792 unsigned long size; 793 } const kmalloc_info[] __initconst = { 794 {NULL, 0}, {"kmalloc-96", 96}, 795 {"kmalloc-192", 192}, {"kmalloc-8", 8}, 796 {"kmalloc-16", 16}, {"kmalloc-32", 32}, 797 {"kmalloc-64", 64}, {"kmalloc-128", 128}, 798 {"kmalloc-256", 256}, {"kmalloc-512", 512}, 799 {"kmalloc-1024", 1024}, {"kmalloc-2048", 2048}, 800 {"kmalloc-4096", 4096}, {"kmalloc-8192", 8192}, 801 {"kmalloc-16384", 16384}, {"kmalloc-32768", 32768}, 802 {"kmalloc-65536", 65536}, {"kmalloc-131072", 131072}, 803 {"kmalloc-262144", 262144}, {"kmalloc-524288", 524288}, 804 {"kmalloc-1048576", 1048576}, {"kmalloc-2097152", 2097152}, 805 {"kmalloc-4194304", 4194304}, {"kmalloc-8388608", 8388608}, 806 {"kmalloc-16777216", 16777216}, {"kmalloc-33554432", 33554432}, 807 {"kmalloc-67108864", 67108864} 808 }; 809 810 /* 811 * Patch up the size_index table if we have strange large alignment 812 * requirements for the kmalloc array. This is only the case for 813 * MIPS it seems. The standard arches will not generate any code here. 814 * 815 * Largest permitted alignment is 256 bytes due to the way we 816 * handle the index determination for the smaller caches. 817 * 818 * Make sure that nothing crazy happens if someone starts tinkering 819 * around with ARCH_KMALLOC_MINALIGN 820 */ 821 void __init setup_kmalloc_cache_index_table(void) 822 { 823 int i; 824 825 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 826 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); 827 828 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 829 int elem = size_index_elem(i); 830 831 if (elem >= ARRAY_SIZE(size_index)) 832 break; 833 size_index[elem] = KMALLOC_SHIFT_LOW; 834 } 835 836 if (KMALLOC_MIN_SIZE >= 64) { 837 /* 838 * The 96 byte size cache is not used if the alignment 839 * is 64 byte. 840 */ 841 for (i = 64 + 8; i <= 96; i += 8) 842 size_index[size_index_elem(i)] = 7; 843 844 } 845 846 if (KMALLOC_MIN_SIZE >= 128) { 847 /* 848 * The 192 byte sized cache is not used if the alignment 849 * is 128 byte. Redirect kmalloc to use the 256 byte cache 850 * instead. 851 */ 852 for (i = 128 + 8; i <= 192; i += 8) 853 size_index[size_index_elem(i)] = 8; 854 } 855 } 856 857 static void __init new_kmalloc_cache(int idx, unsigned long flags) 858 { 859 kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name, 860 kmalloc_info[idx].size, flags); 861 } 862 863 /* 864 * Create the kmalloc array. Some of the regular kmalloc arrays 865 * may already have been created because they were needed to 866 * enable allocations for slab creation. 867 */ 868 void __init create_kmalloc_caches(unsigned long flags) 869 { 870 int i; 871 872 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 873 if (!kmalloc_caches[i]) 874 new_kmalloc_cache(i, flags); 875 876 /* 877 * Caches that are not of the two-to-the-power-of size. 878 * These have to be created immediately after the 879 * earlier power of two caches 880 */ 881 if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) 882 new_kmalloc_cache(1, flags); 883 if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) 884 new_kmalloc_cache(2, flags); 885 } 886 887 /* Kmalloc array is now usable */ 888 slab_state = UP; 889 890 #ifdef CONFIG_ZONE_DMA 891 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { 892 struct kmem_cache *s = kmalloc_caches[i]; 893 894 if (s) { 895 int size = kmalloc_size(i); 896 char *n = kasprintf(GFP_NOWAIT, 897 "dma-kmalloc-%d", size); 898 899 BUG_ON(!n); 900 kmalloc_dma_caches[i] = create_kmalloc_cache(n, 901 size, SLAB_CACHE_DMA | flags); 902 } 903 } 904 #endif 905 } 906 #endif /* !CONFIG_SLOB */ 907 908 /* 909 * To avoid unnecessary overhead, we pass through large allocation requests 910 * directly to the page allocator. We use __GFP_COMP, because we will need to 911 * know the allocation order to free the pages properly in kfree. 912 */ 913 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) 914 { 915 void *ret; 916 struct page *page; 917 918 flags |= __GFP_COMP; 919 page = alloc_kmem_pages(flags, order); 920 ret = page ? page_address(page) : NULL; 921 kmemleak_alloc(ret, size, 1, flags); 922 kasan_kmalloc_large(ret, size); 923 return ret; 924 } 925 EXPORT_SYMBOL(kmalloc_order); 926 927 #ifdef CONFIG_TRACING 928 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) 929 { 930 void *ret = kmalloc_order(size, flags, order); 931 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); 932 return ret; 933 } 934 EXPORT_SYMBOL(kmalloc_order_trace); 935 #endif 936 937 #ifdef CONFIG_SLABINFO 938 939 #ifdef CONFIG_SLAB 940 #define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR) 941 #else 942 #define SLABINFO_RIGHTS S_IRUSR 943 #endif 944 945 static void print_slabinfo_header(struct seq_file *m) 946 { 947 /* 948 * Output format version, so at least we can change it 949 * without _too_ many complaints. 950 */ 951 #ifdef CONFIG_DEBUG_SLAB 952 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 953 #else 954 seq_puts(m, "slabinfo - version: 2.1\n"); 955 #endif 956 seq_puts(m, "# name <active_objs> <num_objs> <objsize> " 957 "<objperslab> <pagesperslab>"); 958 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 959 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 960 #ifdef CONFIG_DEBUG_SLAB 961 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> " 962 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 963 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 964 #endif 965 seq_putc(m, '\n'); 966 } 967 968 void *slab_start(struct seq_file *m, loff_t *pos) 969 { 970 mutex_lock(&slab_mutex); 971 return seq_list_start(&slab_caches, *pos); 972 } 973 974 void *slab_next(struct seq_file *m, void *p, loff_t *pos) 975 { 976 return seq_list_next(p, &slab_caches, pos); 977 } 978 979 void slab_stop(struct seq_file *m, void *p) 980 { 981 mutex_unlock(&slab_mutex); 982 } 983 984 static void 985 memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) 986 { 987 struct kmem_cache *c; 988 struct slabinfo sinfo; 989 990 if (!is_root_cache(s)) 991 return; 992 993 for_each_memcg_cache(c, s) { 994 memset(&sinfo, 0, sizeof(sinfo)); 995 get_slabinfo(c, &sinfo); 996 997 info->active_slabs += sinfo.active_slabs; 998 info->num_slabs += sinfo.num_slabs; 999 info->shared_avail += sinfo.shared_avail; 1000 info->active_objs += sinfo.active_objs; 1001 info->num_objs += sinfo.num_objs; 1002 } 1003 } 1004 1005 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1006 { 1007 struct slabinfo sinfo; 1008 1009 memset(&sinfo, 0, sizeof(sinfo)); 1010 get_slabinfo(s, &sinfo); 1011 1012 memcg_accumulate_slabinfo(s, &sinfo); 1013 1014 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1015 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, 1016 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1017 1018 seq_printf(m, " : tunables %4u %4u %4u", 1019 sinfo.limit, sinfo.batchcount, sinfo.shared); 1020 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1021 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1022 slabinfo_show_stats(m, s); 1023 seq_putc(m, '\n'); 1024 } 1025 1026 static int slab_show(struct seq_file *m, void *p) 1027 { 1028 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1029 1030 if (p == slab_caches.next) 1031 print_slabinfo_header(m); 1032 if (is_root_cache(s)) 1033 cache_show(s, m); 1034 return 0; 1035 } 1036 1037 #ifdef CONFIG_MEMCG_KMEM 1038 int memcg_slab_show(struct seq_file *m, void *p) 1039 { 1040 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1041 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1042 1043 if (p == slab_caches.next) 1044 print_slabinfo_header(m); 1045 if (!is_root_cache(s) && s->memcg_params.memcg == memcg) 1046 cache_show(s, m); 1047 return 0; 1048 } 1049 #endif 1050 1051 /* 1052 * slabinfo_op - iterator that generates /proc/slabinfo 1053 * 1054 * Output layout: 1055 * cache-name 1056 * num-active-objs 1057 * total-objs 1058 * object size 1059 * num-active-slabs 1060 * total-slabs 1061 * num-pages-per-slab 1062 * + further values on SMP and with statistics enabled 1063 */ 1064 static const struct seq_operations slabinfo_op = { 1065 .start = slab_start, 1066 .next = slab_next, 1067 .stop = slab_stop, 1068 .show = slab_show, 1069 }; 1070 1071 static int slabinfo_open(struct inode *inode, struct file *file) 1072 { 1073 return seq_open(file, &slabinfo_op); 1074 } 1075 1076 static const struct file_operations proc_slabinfo_operations = { 1077 .open = slabinfo_open, 1078 .read = seq_read, 1079 .write = slabinfo_write, 1080 .llseek = seq_lseek, 1081 .release = seq_release, 1082 }; 1083 1084 static int __init slab_proc_init(void) 1085 { 1086 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, 1087 &proc_slabinfo_operations); 1088 return 0; 1089 } 1090 module_init(slab_proc_init); 1091 #endif /* CONFIG_SLABINFO */ 1092 1093 static __always_inline void *__do_krealloc(const void *p, size_t new_size, 1094 gfp_t flags) 1095 { 1096 void *ret; 1097 size_t ks = 0; 1098 1099 if (p) 1100 ks = ksize(p); 1101 1102 if (ks >= new_size) { 1103 kasan_krealloc((void *)p, new_size); 1104 return (void *)p; 1105 } 1106 1107 ret = kmalloc_track_caller(new_size, flags); 1108 if (ret && p) 1109 memcpy(ret, p, ks); 1110 1111 return ret; 1112 } 1113 1114 /** 1115 * __krealloc - like krealloc() but don't free @p. 1116 * @p: object to reallocate memory for. 1117 * @new_size: how many bytes of memory are required. 1118 * @flags: the type of memory to allocate. 1119 * 1120 * This function is like krealloc() except it never frees the originally 1121 * allocated buffer. Use this if you don't want to free the buffer immediately 1122 * like, for example, with RCU. 1123 */ 1124 void *__krealloc(const void *p, size_t new_size, gfp_t flags) 1125 { 1126 if (unlikely(!new_size)) 1127 return ZERO_SIZE_PTR; 1128 1129 return __do_krealloc(p, new_size, flags); 1130 1131 } 1132 EXPORT_SYMBOL(__krealloc); 1133 1134 /** 1135 * krealloc - reallocate memory. The contents will remain unchanged. 1136 * @p: object to reallocate memory for. 1137 * @new_size: how many bytes of memory are required. 1138 * @flags: the type of memory to allocate. 1139 * 1140 * The contents of the object pointed to are preserved up to the 1141 * lesser of the new and old sizes. If @p is %NULL, krealloc() 1142 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a 1143 * %NULL pointer, the object pointed to is freed. 1144 */ 1145 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1146 { 1147 void *ret; 1148 1149 if (unlikely(!new_size)) { 1150 kfree(p); 1151 return ZERO_SIZE_PTR; 1152 } 1153 1154 ret = __do_krealloc(p, new_size, flags); 1155 if (ret && p != ret) 1156 kfree(p); 1157 1158 return ret; 1159 } 1160 EXPORT_SYMBOL(krealloc); 1161 1162 /** 1163 * kzfree - like kfree but zero memory 1164 * @p: object to free memory of 1165 * 1166 * The memory of the object @p points to is zeroed before freed. 1167 * If @p is %NULL, kzfree() does nothing. 1168 * 1169 * Note: this function zeroes the whole allocated buffer which can be a good 1170 * deal bigger than the requested buffer size passed to kmalloc(). So be 1171 * careful when using this function in performance sensitive code. 1172 */ 1173 void kzfree(const void *p) 1174 { 1175 size_t ks; 1176 void *mem = (void *)p; 1177 1178 if (unlikely(ZERO_OR_NULL_PTR(mem))) 1179 return; 1180 ks = ksize(mem); 1181 memset(mem, 0, ks); 1182 kfree(mem); 1183 } 1184 EXPORT_SYMBOL(kzfree); 1185 1186 /* Tracepoints definitions. */ 1187 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1188 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1189 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); 1190 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); 1191 EXPORT_TRACEPOINT_SYMBOL(kfree); 1192 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1193