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 void __kmem_cache_free_bulk(struct kmem_cache *s, size_t nr, void **p) 108 { 109 size_t i; 110 111 for (i = 0; i < nr; i++) 112 kmem_cache_free(s, p[i]); 113 } 114 115 bool __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr, 116 void **p) 117 { 118 size_t i; 119 120 for (i = 0; i < nr; i++) { 121 void *x = p[i] = kmem_cache_alloc(s, flags); 122 if (!x) { 123 __kmem_cache_free_bulk(s, i, p); 124 return false; 125 } 126 } 127 return true; 128 } 129 130 #ifdef CONFIG_MEMCG_KMEM 131 void slab_init_memcg_params(struct kmem_cache *s) 132 { 133 s->memcg_params.is_root_cache = true; 134 INIT_LIST_HEAD(&s->memcg_params.list); 135 RCU_INIT_POINTER(s->memcg_params.memcg_caches, NULL); 136 } 137 138 static int init_memcg_params(struct kmem_cache *s, 139 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 140 { 141 struct memcg_cache_array *arr; 142 143 if (memcg) { 144 s->memcg_params.is_root_cache = false; 145 s->memcg_params.memcg = memcg; 146 s->memcg_params.root_cache = root_cache; 147 return 0; 148 } 149 150 slab_init_memcg_params(s); 151 152 if (!memcg_nr_cache_ids) 153 return 0; 154 155 arr = kzalloc(sizeof(struct memcg_cache_array) + 156 memcg_nr_cache_ids * sizeof(void *), 157 GFP_KERNEL); 158 if (!arr) 159 return -ENOMEM; 160 161 RCU_INIT_POINTER(s->memcg_params.memcg_caches, arr); 162 return 0; 163 } 164 165 static void destroy_memcg_params(struct kmem_cache *s) 166 { 167 if (is_root_cache(s)) 168 kfree(rcu_access_pointer(s->memcg_params.memcg_caches)); 169 } 170 171 static int update_memcg_params(struct kmem_cache *s, int new_array_size) 172 { 173 struct memcg_cache_array *old, *new; 174 175 if (!is_root_cache(s)) 176 return 0; 177 178 new = kzalloc(sizeof(struct memcg_cache_array) + 179 new_array_size * sizeof(void *), GFP_KERNEL); 180 if (!new) 181 return -ENOMEM; 182 183 old = rcu_dereference_protected(s->memcg_params.memcg_caches, 184 lockdep_is_held(&slab_mutex)); 185 if (old) 186 memcpy(new->entries, old->entries, 187 memcg_nr_cache_ids * sizeof(void *)); 188 189 rcu_assign_pointer(s->memcg_params.memcg_caches, new); 190 if (old) 191 kfree_rcu(old, rcu); 192 return 0; 193 } 194 195 int memcg_update_all_caches(int num_memcgs) 196 { 197 struct kmem_cache *s; 198 int ret = 0; 199 200 mutex_lock(&slab_mutex); 201 list_for_each_entry(s, &slab_caches, list) { 202 ret = update_memcg_params(s, num_memcgs); 203 /* 204 * Instead of freeing the memory, we'll just leave the caches 205 * up to this point in an updated state. 206 */ 207 if (ret) 208 break; 209 } 210 mutex_unlock(&slab_mutex); 211 return ret; 212 } 213 #else 214 static inline int init_memcg_params(struct kmem_cache *s, 215 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 216 { 217 return 0; 218 } 219 220 static inline void destroy_memcg_params(struct kmem_cache *s) 221 { 222 } 223 #endif /* CONFIG_MEMCG_KMEM */ 224 225 /* 226 * Find a mergeable slab cache 227 */ 228 int slab_unmergeable(struct kmem_cache *s) 229 { 230 if (slab_nomerge || (s->flags & SLAB_NEVER_MERGE)) 231 return 1; 232 233 if (!is_root_cache(s)) 234 return 1; 235 236 if (s->ctor) 237 return 1; 238 239 /* 240 * We may have set a slab to be unmergeable during bootstrap. 241 */ 242 if (s->refcount < 0) 243 return 1; 244 245 return 0; 246 } 247 248 struct kmem_cache *find_mergeable(size_t size, size_t align, 249 unsigned long flags, const char *name, void (*ctor)(void *)) 250 { 251 struct kmem_cache *s; 252 253 if (slab_nomerge || (flags & SLAB_NEVER_MERGE)) 254 return NULL; 255 256 if (ctor) 257 return NULL; 258 259 size = ALIGN(size, sizeof(void *)); 260 align = calculate_alignment(flags, align, size); 261 size = ALIGN(size, align); 262 flags = kmem_cache_flags(size, flags, name, NULL); 263 264 list_for_each_entry_reverse(s, &slab_caches, list) { 265 if (slab_unmergeable(s)) 266 continue; 267 268 if (size > s->size) 269 continue; 270 271 if ((flags & SLAB_MERGE_SAME) != (s->flags & SLAB_MERGE_SAME)) 272 continue; 273 /* 274 * Check if alignment is compatible. 275 * Courtesy of Adrian Drzewiecki 276 */ 277 if ((s->size & ~(align - 1)) != s->size) 278 continue; 279 280 if (s->size - size >= sizeof(void *)) 281 continue; 282 283 if (IS_ENABLED(CONFIG_SLAB) && align && 284 (align > s->align || s->align % align)) 285 continue; 286 287 return s; 288 } 289 return NULL; 290 } 291 292 /* 293 * Figure out what the alignment of the objects will be given a set of 294 * flags, a user specified alignment and the size of the objects. 295 */ 296 unsigned long calculate_alignment(unsigned long flags, 297 unsigned long align, unsigned long size) 298 { 299 /* 300 * If the user wants hardware cache aligned objects then follow that 301 * suggestion if the object is sufficiently large. 302 * 303 * The hardware cache alignment cannot override the specified 304 * alignment though. If that is greater then use it. 305 */ 306 if (flags & SLAB_HWCACHE_ALIGN) { 307 unsigned long ralign = cache_line_size(); 308 while (size <= ralign / 2) 309 ralign /= 2; 310 align = max(align, ralign); 311 } 312 313 if (align < ARCH_SLAB_MINALIGN) 314 align = ARCH_SLAB_MINALIGN; 315 316 return ALIGN(align, sizeof(void *)); 317 } 318 319 static struct kmem_cache * 320 do_kmem_cache_create(const char *name, size_t object_size, size_t size, 321 size_t align, unsigned long flags, void (*ctor)(void *), 322 struct mem_cgroup *memcg, struct kmem_cache *root_cache) 323 { 324 struct kmem_cache *s; 325 int err; 326 327 err = -ENOMEM; 328 s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL); 329 if (!s) 330 goto out; 331 332 s->name = name; 333 s->object_size = object_size; 334 s->size = size; 335 s->align = align; 336 s->ctor = ctor; 337 338 err = init_memcg_params(s, memcg, root_cache); 339 if (err) 340 goto out_free_cache; 341 342 err = __kmem_cache_create(s, flags); 343 if (err) 344 goto out_free_cache; 345 346 s->refcount = 1; 347 list_add(&s->list, &slab_caches); 348 out: 349 if (err) 350 return ERR_PTR(err); 351 return s; 352 353 out_free_cache: 354 destroy_memcg_params(s); 355 kmem_cache_free(kmem_cache, s); 356 goto out; 357 } 358 359 /* 360 * kmem_cache_create - Create a cache. 361 * @name: A string which is used in /proc/slabinfo to identify this cache. 362 * @size: The size of objects to be created in this cache. 363 * @align: The required alignment for the objects. 364 * @flags: SLAB flags 365 * @ctor: A constructor for the objects. 366 * 367 * Returns a ptr to the cache on success, NULL on failure. 368 * Cannot be called within a interrupt, but can be interrupted. 369 * The @ctor is run when new pages are allocated by the cache. 370 * 371 * The flags are 372 * 373 * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) 374 * to catch references to uninitialised memory. 375 * 376 * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check 377 * for buffer overruns. 378 * 379 * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware 380 * cacheline. This can be beneficial if you're counting cycles as closely 381 * as davem. 382 */ 383 struct kmem_cache * 384 kmem_cache_create(const char *name, size_t size, size_t align, 385 unsigned long flags, void (*ctor)(void *)) 386 { 387 struct kmem_cache *s; 388 const char *cache_name; 389 int err; 390 391 get_online_cpus(); 392 get_online_mems(); 393 memcg_get_cache_ids(); 394 395 mutex_lock(&slab_mutex); 396 397 err = kmem_cache_sanity_check(name, size); 398 if (err) { 399 s = NULL; /* suppress uninit var warning */ 400 goto out_unlock; 401 } 402 403 /* 404 * Some allocators will constraint the set of valid flags to a subset 405 * of all flags. We expect them to define CACHE_CREATE_MASK in this 406 * case, and we'll just provide them with a sanitized version of the 407 * passed flags. 408 */ 409 flags &= CACHE_CREATE_MASK; 410 411 s = __kmem_cache_alias(name, size, align, flags, ctor); 412 if (s) 413 goto out_unlock; 414 415 cache_name = kstrdup_const(name, GFP_KERNEL); 416 if (!cache_name) { 417 err = -ENOMEM; 418 goto out_unlock; 419 } 420 421 s = do_kmem_cache_create(cache_name, size, size, 422 calculate_alignment(flags, align, size), 423 flags, ctor, NULL, NULL); 424 if (IS_ERR(s)) { 425 err = PTR_ERR(s); 426 kfree_const(cache_name); 427 } 428 429 out_unlock: 430 mutex_unlock(&slab_mutex); 431 432 memcg_put_cache_ids(); 433 put_online_mems(); 434 put_online_cpus(); 435 436 if (err) { 437 if (flags & SLAB_PANIC) 438 panic("kmem_cache_create: Failed to create slab '%s'. Error %d\n", 439 name, err); 440 else { 441 printk(KERN_WARNING "kmem_cache_create(%s) failed with error %d", 442 name, err); 443 dump_stack(); 444 } 445 return NULL; 446 } 447 return s; 448 } 449 EXPORT_SYMBOL(kmem_cache_create); 450 451 static int do_kmem_cache_shutdown(struct kmem_cache *s, 452 struct list_head *release, bool *need_rcu_barrier) 453 { 454 if (__kmem_cache_shutdown(s) != 0) { 455 printk(KERN_ERR "kmem_cache_destroy %s: " 456 "Slab cache still has objects\n", s->name); 457 dump_stack(); 458 return -EBUSY; 459 } 460 461 if (s->flags & SLAB_DESTROY_BY_RCU) 462 *need_rcu_barrier = true; 463 464 #ifdef CONFIG_MEMCG_KMEM 465 if (!is_root_cache(s)) 466 list_del(&s->memcg_params.list); 467 #endif 468 list_move(&s->list, release); 469 return 0; 470 } 471 472 static void do_kmem_cache_release(struct list_head *release, 473 bool need_rcu_barrier) 474 { 475 struct kmem_cache *s, *s2; 476 477 if (need_rcu_barrier) 478 rcu_barrier(); 479 480 list_for_each_entry_safe(s, s2, release, list) { 481 #ifdef SLAB_SUPPORTS_SYSFS 482 sysfs_slab_remove(s); 483 #else 484 slab_kmem_cache_release(s); 485 #endif 486 } 487 } 488 489 #ifdef CONFIG_MEMCG_KMEM 490 /* 491 * memcg_create_kmem_cache - Create a cache for a memory cgroup. 492 * @memcg: The memory cgroup the new cache is for. 493 * @root_cache: The parent of the new cache. 494 * 495 * This function attempts to create a kmem cache that will serve allocation 496 * requests going from @memcg to @root_cache. The new cache inherits properties 497 * from its parent. 498 */ 499 void memcg_create_kmem_cache(struct mem_cgroup *memcg, 500 struct kmem_cache *root_cache) 501 { 502 static char memcg_name_buf[NAME_MAX + 1]; /* protected by slab_mutex */ 503 struct cgroup_subsys_state *css = &memcg->css; 504 struct memcg_cache_array *arr; 505 struct kmem_cache *s = NULL; 506 char *cache_name; 507 int idx; 508 509 get_online_cpus(); 510 get_online_mems(); 511 512 mutex_lock(&slab_mutex); 513 514 /* 515 * The memory cgroup could have been deactivated while the cache 516 * creation work was pending. 517 */ 518 if (!memcg_kmem_is_active(memcg)) 519 goto out_unlock; 520 521 idx = memcg_cache_id(memcg); 522 arr = rcu_dereference_protected(root_cache->memcg_params.memcg_caches, 523 lockdep_is_held(&slab_mutex)); 524 525 /* 526 * Since per-memcg caches are created asynchronously on first 527 * allocation (see memcg_kmem_get_cache()), several threads can try to 528 * create the same cache, but only one of them may succeed. 529 */ 530 if (arr->entries[idx]) 531 goto out_unlock; 532 533 cgroup_name(css->cgroup, memcg_name_buf, sizeof(memcg_name_buf)); 534 cache_name = kasprintf(GFP_KERNEL, "%s(%d:%s)", root_cache->name, 535 css->id, memcg_name_buf); 536 if (!cache_name) 537 goto out_unlock; 538 539 s = do_kmem_cache_create(cache_name, root_cache->object_size, 540 root_cache->size, root_cache->align, 541 root_cache->flags, root_cache->ctor, 542 memcg, root_cache); 543 /* 544 * If we could not create a memcg cache, do not complain, because 545 * that's not critical at all as we can always proceed with the root 546 * cache. 547 */ 548 if (IS_ERR(s)) { 549 kfree(cache_name); 550 goto out_unlock; 551 } 552 553 list_add(&s->memcg_params.list, &root_cache->memcg_params.list); 554 555 /* 556 * Since readers won't lock (see cache_from_memcg_idx()), we need a 557 * barrier here to ensure nobody will see the kmem_cache partially 558 * initialized. 559 */ 560 smp_wmb(); 561 arr->entries[idx] = s; 562 563 out_unlock: 564 mutex_unlock(&slab_mutex); 565 566 put_online_mems(); 567 put_online_cpus(); 568 } 569 570 void memcg_deactivate_kmem_caches(struct mem_cgroup *memcg) 571 { 572 int idx; 573 struct memcg_cache_array *arr; 574 struct kmem_cache *s, *c; 575 576 idx = memcg_cache_id(memcg); 577 578 get_online_cpus(); 579 get_online_mems(); 580 581 mutex_lock(&slab_mutex); 582 list_for_each_entry(s, &slab_caches, list) { 583 if (!is_root_cache(s)) 584 continue; 585 586 arr = rcu_dereference_protected(s->memcg_params.memcg_caches, 587 lockdep_is_held(&slab_mutex)); 588 c = arr->entries[idx]; 589 if (!c) 590 continue; 591 592 __kmem_cache_shrink(c, true); 593 arr->entries[idx] = NULL; 594 } 595 mutex_unlock(&slab_mutex); 596 597 put_online_mems(); 598 put_online_cpus(); 599 } 600 601 void memcg_destroy_kmem_caches(struct mem_cgroup *memcg) 602 { 603 LIST_HEAD(release); 604 bool need_rcu_barrier = false; 605 struct kmem_cache *s, *s2; 606 607 get_online_cpus(); 608 get_online_mems(); 609 610 mutex_lock(&slab_mutex); 611 list_for_each_entry_safe(s, s2, &slab_caches, list) { 612 if (is_root_cache(s) || s->memcg_params.memcg != memcg) 613 continue; 614 /* 615 * The cgroup is about to be freed and therefore has no charges 616 * left. Hence, all its caches must be empty by now. 617 */ 618 BUG_ON(do_kmem_cache_shutdown(s, &release, &need_rcu_barrier)); 619 } 620 mutex_unlock(&slab_mutex); 621 622 put_online_mems(); 623 put_online_cpus(); 624 625 do_kmem_cache_release(&release, need_rcu_barrier); 626 } 627 #endif /* CONFIG_MEMCG_KMEM */ 628 629 void slab_kmem_cache_release(struct kmem_cache *s) 630 { 631 destroy_memcg_params(s); 632 kfree_const(s->name); 633 kmem_cache_free(kmem_cache, s); 634 } 635 636 void kmem_cache_destroy(struct kmem_cache *s) 637 { 638 struct kmem_cache *c, *c2; 639 LIST_HEAD(release); 640 bool need_rcu_barrier = false; 641 bool busy = false; 642 643 if (unlikely(!s)) 644 return; 645 646 BUG_ON(!is_root_cache(s)); 647 648 get_online_cpus(); 649 get_online_mems(); 650 651 mutex_lock(&slab_mutex); 652 653 s->refcount--; 654 if (s->refcount) 655 goto out_unlock; 656 657 for_each_memcg_cache_safe(c, c2, s) { 658 if (do_kmem_cache_shutdown(c, &release, &need_rcu_barrier)) 659 busy = true; 660 } 661 662 if (!busy) 663 do_kmem_cache_shutdown(s, &release, &need_rcu_barrier); 664 665 out_unlock: 666 mutex_unlock(&slab_mutex); 667 668 put_online_mems(); 669 put_online_cpus(); 670 671 do_kmem_cache_release(&release, need_rcu_barrier); 672 } 673 EXPORT_SYMBOL(kmem_cache_destroy); 674 675 /** 676 * kmem_cache_shrink - Shrink a cache. 677 * @cachep: The cache to shrink. 678 * 679 * Releases as many slabs as possible for a cache. 680 * To help debugging, a zero exit status indicates all slabs were released. 681 */ 682 int kmem_cache_shrink(struct kmem_cache *cachep) 683 { 684 int ret; 685 686 get_online_cpus(); 687 get_online_mems(); 688 ret = __kmem_cache_shrink(cachep, false); 689 put_online_mems(); 690 put_online_cpus(); 691 return ret; 692 } 693 EXPORT_SYMBOL(kmem_cache_shrink); 694 695 int slab_is_available(void) 696 { 697 return slab_state >= UP; 698 } 699 700 #ifndef CONFIG_SLOB 701 /* Create a cache during boot when no slab services are available yet */ 702 void __init create_boot_cache(struct kmem_cache *s, const char *name, size_t size, 703 unsigned long flags) 704 { 705 int err; 706 707 s->name = name; 708 s->size = s->object_size = size; 709 s->align = calculate_alignment(flags, ARCH_KMALLOC_MINALIGN, size); 710 711 slab_init_memcg_params(s); 712 713 err = __kmem_cache_create(s, flags); 714 715 if (err) 716 panic("Creation of kmalloc slab %s size=%zu failed. Reason %d\n", 717 name, size, err); 718 719 s->refcount = -1; /* Exempt from merging for now */ 720 } 721 722 struct kmem_cache *__init create_kmalloc_cache(const char *name, size_t size, 723 unsigned long flags) 724 { 725 struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT); 726 727 if (!s) 728 panic("Out of memory when creating slab %s\n", name); 729 730 create_boot_cache(s, name, size, flags); 731 list_add(&s->list, &slab_caches); 732 s->refcount = 1; 733 return s; 734 } 735 736 struct kmem_cache *kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; 737 EXPORT_SYMBOL(kmalloc_caches); 738 739 #ifdef CONFIG_ZONE_DMA 740 struct kmem_cache *kmalloc_dma_caches[KMALLOC_SHIFT_HIGH + 1]; 741 EXPORT_SYMBOL(kmalloc_dma_caches); 742 #endif 743 744 /* 745 * Conversion table for small slabs sizes / 8 to the index in the 746 * kmalloc array. This is necessary for slabs < 192 since we have non power 747 * of two cache sizes there. The size of larger slabs can be determined using 748 * fls. 749 */ 750 static s8 size_index[24] = { 751 3, /* 8 */ 752 4, /* 16 */ 753 5, /* 24 */ 754 5, /* 32 */ 755 6, /* 40 */ 756 6, /* 48 */ 757 6, /* 56 */ 758 6, /* 64 */ 759 1, /* 72 */ 760 1, /* 80 */ 761 1, /* 88 */ 762 1, /* 96 */ 763 7, /* 104 */ 764 7, /* 112 */ 765 7, /* 120 */ 766 7, /* 128 */ 767 2, /* 136 */ 768 2, /* 144 */ 769 2, /* 152 */ 770 2, /* 160 */ 771 2, /* 168 */ 772 2, /* 176 */ 773 2, /* 184 */ 774 2 /* 192 */ 775 }; 776 777 static inline int size_index_elem(size_t bytes) 778 { 779 return (bytes - 1) / 8; 780 } 781 782 /* 783 * Find the kmem_cache structure that serves a given size of 784 * allocation 785 */ 786 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags) 787 { 788 int index; 789 790 if (unlikely(size > KMALLOC_MAX_SIZE)) { 791 WARN_ON_ONCE(!(flags & __GFP_NOWARN)); 792 return NULL; 793 } 794 795 if (size <= 192) { 796 if (!size) 797 return ZERO_SIZE_PTR; 798 799 index = size_index[size_index_elem(size)]; 800 } else 801 index = fls(size - 1); 802 803 #ifdef CONFIG_ZONE_DMA 804 if (unlikely((flags & GFP_DMA))) 805 return kmalloc_dma_caches[index]; 806 807 #endif 808 return kmalloc_caches[index]; 809 } 810 811 /* 812 * kmalloc_info[] is to make slub_debug=,kmalloc-xx option work at boot time. 813 * kmalloc_index() supports up to 2^26=64MB, so the final entry of the table is 814 * kmalloc-67108864. 815 */ 816 static struct { 817 const char *name; 818 unsigned long size; 819 } const kmalloc_info[] __initconst = { 820 {NULL, 0}, {"kmalloc-96", 96}, 821 {"kmalloc-192", 192}, {"kmalloc-8", 8}, 822 {"kmalloc-16", 16}, {"kmalloc-32", 32}, 823 {"kmalloc-64", 64}, {"kmalloc-128", 128}, 824 {"kmalloc-256", 256}, {"kmalloc-512", 512}, 825 {"kmalloc-1024", 1024}, {"kmalloc-2048", 2048}, 826 {"kmalloc-4096", 4096}, {"kmalloc-8192", 8192}, 827 {"kmalloc-16384", 16384}, {"kmalloc-32768", 32768}, 828 {"kmalloc-65536", 65536}, {"kmalloc-131072", 131072}, 829 {"kmalloc-262144", 262144}, {"kmalloc-524288", 524288}, 830 {"kmalloc-1048576", 1048576}, {"kmalloc-2097152", 2097152}, 831 {"kmalloc-4194304", 4194304}, {"kmalloc-8388608", 8388608}, 832 {"kmalloc-16777216", 16777216}, {"kmalloc-33554432", 33554432}, 833 {"kmalloc-67108864", 67108864} 834 }; 835 836 /* 837 * Patch up the size_index table if we have strange large alignment 838 * requirements for the kmalloc array. This is only the case for 839 * MIPS it seems. The standard arches will not generate any code here. 840 * 841 * Largest permitted alignment is 256 bytes due to the way we 842 * handle the index determination for the smaller caches. 843 * 844 * Make sure that nothing crazy happens if someone starts tinkering 845 * around with ARCH_KMALLOC_MINALIGN 846 */ 847 void __init setup_kmalloc_cache_index_table(void) 848 { 849 int i; 850 851 BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 || 852 (KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1))); 853 854 for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) { 855 int elem = size_index_elem(i); 856 857 if (elem >= ARRAY_SIZE(size_index)) 858 break; 859 size_index[elem] = KMALLOC_SHIFT_LOW; 860 } 861 862 if (KMALLOC_MIN_SIZE >= 64) { 863 /* 864 * The 96 byte size cache is not used if the alignment 865 * is 64 byte. 866 */ 867 for (i = 64 + 8; i <= 96; i += 8) 868 size_index[size_index_elem(i)] = 7; 869 870 } 871 872 if (KMALLOC_MIN_SIZE >= 128) { 873 /* 874 * The 192 byte sized cache is not used if the alignment 875 * is 128 byte. Redirect kmalloc to use the 256 byte cache 876 * instead. 877 */ 878 for (i = 128 + 8; i <= 192; i += 8) 879 size_index[size_index_elem(i)] = 8; 880 } 881 } 882 883 static void __init new_kmalloc_cache(int idx, unsigned long flags) 884 { 885 kmalloc_caches[idx] = create_kmalloc_cache(kmalloc_info[idx].name, 886 kmalloc_info[idx].size, flags); 887 } 888 889 /* 890 * Create the kmalloc array. Some of the regular kmalloc arrays 891 * may already have been created because they were needed to 892 * enable allocations for slab creation. 893 */ 894 void __init create_kmalloc_caches(unsigned long flags) 895 { 896 int i; 897 898 for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) { 899 if (!kmalloc_caches[i]) 900 new_kmalloc_cache(i, flags); 901 902 /* 903 * Caches that are not of the two-to-the-power-of size. 904 * These have to be created immediately after the 905 * earlier power of two caches 906 */ 907 if (KMALLOC_MIN_SIZE <= 32 && !kmalloc_caches[1] && i == 6) 908 new_kmalloc_cache(1, flags); 909 if (KMALLOC_MIN_SIZE <= 64 && !kmalloc_caches[2] && i == 7) 910 new_kmalloc_cache(2, flags); 911 } 912 913 /* Kmalloc array is now usable */ 914 slab_state = UP; 915 916 #ifdef CONFIG_ZONE_DMA 917 for (i = 0; i <= KMALLOC_SHIFT_HIGH; i++) { 918 struct kmem_cache *s = kmalloc_caches[i]; 919 920 if (s) { 921 int size = kmalloc_size(i); 922 char *n = kasprintf(GFP_NOWAIT, 923 "dma-kmalloc-%d", size); 924 925 BUG_ON(!n); 926 kmalloc_dma_caches[i] = create_kmalloc_cache(n, 927 size, SLAB_CACHE_DMA | flags); 928 } 929 } 930 #endif 931 } 932 #endif /* !CONFIG_SLOB */ 933 934 /* 935 * To avoid unnecessary overhead, we pass through large allocation requests 936 * directly to the page allocator. We use __GFP_COMP, because we will need to 937 * know the allocation order to free the pages properly in kfree. 938 */ 939 void *kmalloc_order(size_t size, gfp_t flags, unsigned int order) 940 { 941 void *ret; 942 struct page *page; 943 944 flags |= __GFP_COMP; 945 page = alloc_kmem_pages(flags, order); 946 ret = page ? page_address(page) : NULL; 947 kmemleak_alloc(ret, size, 1, flags); 948 kasan_kmalloc_large(ret, size); 949 return ret; 950 } 951 EXPORT_SYMBOL(kmalloc_order); 952 953 #ifdef CONFIG_TRACING 954 void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order) 955 { 956 void *ret = kmalloc_order(size, flags, order); 957 trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags); 958 return ret; 959 } 960 EXPORT_SYMBOL(kmalloc_order_trace); 961 #endif 962 963 #ifdef CONFIG_SLABINFO 964 965 #ifdef CONFIG_SLAB 966 #define SLABINFO_RIGHTS (S_IWUSR | S_IRUSR) 967 #else 968 #define SLABINFO_RIGHTS S_IRUSR 969 #endif 970 971 static void print_slabinfo_header(struct seq_file *m) 972 { 973 /* 974 * Output format version, so at least we can change it 975 * without _too_ many complaints. 976 */ 977 #ifdef CONFIG_DEBUG_SLAB 978 seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); 979 #else 980 seq_puts(m, "slabinfo - version: 2.1\n"); 981 #endif 982 seq_puts(m, "# name <active_objs> <num_objs> <objsize> " 983 "<objperslab> <pagesperslab>"); 984 seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); 985 seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); 986 #ifdef CONFIG_DEBUG_SLAB 987 seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped> " 988 "<error> <maxfreeable> <nodeallocs> <remotefrees> <alienoverflow>"); 989 seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); 990 #endif 991 seq_putc(m, '\n'); 992 } 993 994 void *slab_start(struct seq_file *m, loff_t *pos) 995 { 996 mutex_lock(&slab_mutex); 997 return seq_list_start(&slab_caches, *pos); 998 } 999 1000 void *slab_next(struct seq_file *m, void *p, loff_t *pos) 1001 { 1002 return seq_list_next(p, &slab_caches, pos); 1003 } 1004 1005 void slab_stop(struct seq_file *m, void *p) 1006 { 1007 mutex_unlock(&slab_mutex); 1008 } 1009 1010 static void 1011 memcg_accumulate_slabinfo(struct kmem_cache *s, struct slabinfo *info) 1012 { 1013 struct kmem_cache *c; 1014 struct slabinfo sinfo; 1015 1016 if (!is_root_cache(s)) 1017 return; 1018 1019 for_each_memcg_cache(c, s) { 1020 memset(&sinfo, 0, sizeof(sinfo)); 1021 get_slabinfo(c, &sinfo); 1022 1023 info->active_slabs += sinfo.active_slabs; 1024 info->num_slabs += sinfo.num_slabs; 1025 info->shared_avail += sinfo.shared_avail; 1026 info->active_objs += sinfo.active_objs; 1027 info->num_objs += sinfo.num_objs; 1028 } 1029 } 1030 1031 static void cache_show(struct kmem_cache *s, struct seq_file *m) 1032 { 1033 struct slabinfo sinfo; 1034 1035 memset(&sinfo, 0, sizeof(sinfo)); 1036 get_slabinfo(s, &sinfo); 1037 1038 memcg_accumulate_slabinfo(s, &sinfo); 1039 1040 seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", 1041 cache_name(s), sinfo.active_objs, sinfo.num_objs, s->size, 1042 sinfo.objects_per_slab, (1 << sinfo.cache_order)); 1043 1044 seq_printf(m, " : tunables %4u %4u %4u", 1045 sinfo.limit, sinfo.batchcount, sinfo.shared); 1046 seq_printf(m, " : slabdata %6lu %6lu %6lu", 1047 sinfo.active_slabs, sinfo.num_slabs, sinfo.shared_avail); 1048 slabinfo_show_stats(m, s); 1049 seq_putc(m, '\n'); 1050 } 1051 1052 static int slab_show(struct seq_file *m, void *p) 1053 { 1054 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1055 1056 if (p == slab_caches.next) 1057 print_slabinfo_header(m); 1058 if (is_root_cache(s)) 1059 cache_show(s, m); 1060 return 0; 1061 } 1062 1063 #ifdef CONFIG_MEMCG_KMEM 1064 int memcg_slab_show(struct seq_file *m, void *p) 1065 { 1066 struct kmem_cache *s = list_entry(p, struct kmem_cache, list); 1067 struct mem_cgroup *memcg = mem_cgroup_from_css(seq_css(m)); 1068 1069 if (p == slab_caches.next) 1070 print_slabinfo_header(m); 1071 if (!is_root_cache(s) && s->memcg_params.memcg == memcg) 1072 cache_show(s, m); 1073 return 0; 1074 } 1075 #endif 1076 1077 /* 1078 * slabinfo_op - iterator that generates /proc/slabinfo 1079 * 1080 * Output layout: 1081 * cache-name 1082 * num-active-objs 1083 * total-objs 1084 * object size 1085 * num-active-slabs 1086 * total-slabs 1087 * num-pages-per-slab 1088 * + further values on SMP and with statistics enabled 1089 */ 1090 static const struct seq_operations slabinfo_op = { 1091 .start = slab_start, 1092 .next = slab_next, 1093 .stop = slab_stop, 1094 .show = slab_show, 1095 }; 1096 1097 static int slabinfo_open(struct inode *inode, struct file *file) 1098 { 1099 return seq_open(file, &slabinfo_op); 1100 } 1101 1102 static const struct file_operations proc_slabinfo_operations = { 1103 .open = slabinfo_open, 1104 .read = seq_read, 1105 .write = slabinfo_write, 1106 .llseek = seq_lseek, 1107 .release = seq_release, 1108 }; 1109 1110 static int __init slab_proc_init(void) 1111 { 1112 proc_create("slabinfo", SLABINFO_RIGHTS, NULL, 1113 &proc_slabinfo_operations); 1114 return 0; 1115 } 1116 module_init(slab_proc_init); 1117 #endif /* CONFIG_SLABINFO */ 1118 1119 static __always_inline void *__do_krealloc(const void *p, size_t new_size, 1120 gfp_t flags) 1121 { 1122 void *ret; 1123 size_t ks = 0; 1124 1125 if (p) 1126 ks = ksize(p); 1127 1128 if (ks >= new_size) { 1129 kasan_krealloc((void *)p, new_size); 1130 return (void *)p; 1131 } 1132 1133 ret = kmalloc_track_caller(new_size, flags); 1134 if (ret && p) 1135 memcpy(ret, p, ks); 1136 1137 return ret; 1138 } 1139 1140 /** 1141 * __krealloc - like krealloc() but don't free @p. 1142 * @p: object to reallocate memory for. 1143 * @new_size: how many bytes of memory are required. 1144 * @flags: the type of memory to allocate. 1145 * 1146 * This function is like krealloc() except it never frees the originally 1147 * allocated buffer. Use this if you don't want to free the buffer immediately 1148 * like, for example, with RCU. 1149 */ 1150 void *__krealloc(const void *p, size_t new_size, gfp_t flags) 1151 { 1152 if (unlikely(!new_size)) 1153 return ZERO_SIZE_PTR; 1154 1155 return __do_krealloc(p, new_size, flags); 1156 1157 } 1158 EXPORT_SYMBOL(__krealloc); 1159 1160 /** 1161 * krealloc - reallocate memory. The contents will remain unchanged. 1162 * @p: object to reallocate memory for. 1163 * @new_size: how many bytes of memory are required. 1164 * @flags: the type of memory to allocate. 1165 * 1166 * The contents of the object pointed to are preserved up to the 1167 * lesser of the new and old sizes. If @p is %NULL, krealloc() 1168 * behaves exactly like kmalloc(). If @new_size is 0 and @p is not a 1169 * %NULL pointer, the object pointed to is freed. 1170 */ 1171 void *krealloc(const void *p, size_t new_size, gfp_t flags) 1172 { 1173 void *ret; 1174 1175 if (unlikely(!new_size)) { 1176 kfree(p); 1177 return ZERO_SIZE_PTR; 1178 } 1179 1180 ret = __do_krealloc(p, new_size, flags); 1181 if (ret && p != ret) 1182 kfree(p); 1183 1184 return ret; 1185 } 1186 EXPORT_SYMBOL(krealloc); 1187 1188 /** 1189 * kzfree - like kfree but zero memory 1190 * @p: object to free memory of 1191 * 1192 * The memory of the object @p points to is zeroed before freed. 1193 * If @p is %NULL, kzfree() does nothing. 1194 * 1195 * Note: this function zeroes the whole allocated buffer which can be a good 1196 * deal bigger than the requested buffer size passed to kmalloc(). So be 1197 * careful when using this function in performance sensitive code. 1198 */ 1199 void kzfree(const void *p) 1200 { 1201 size_t ks; 1202 void *mem = (void *)p; 1203 1204 if (unlikely(ZERO_OR_NULL_PTR(mem))) 1205 return; 1206 ks = ksize(mem); 1207 memset(mem, 0, ks); 1208 kfree(mem); 1209 } 1210 EXPORT_SYMBOL(kzfree); 1211 1212 /* Tracepoints definitions. */ 1213 EXPORT_TRACEPOINT_SYMBOL(kmalloc); 1214 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc); 1215 EXPORT_TRACEPOINT_SYMBOL(kmalloc_node); 1216 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_alloc_node); 1217 EXPORT_TRACEPOINT_SYMBOL(kfree); 1218 EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free); 1219