1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef MM_SLAB_H 3 #define MM_SLAB_H 4 /* 5 * Internal slab definitions 6 */ 7 void __init kmem_cache_init(void); 8 9 #ifdef CONFIG_64BIT 10 # ifdef system_has_cmpxchg128 11 # define system_has_freelist_aba() system_has_cmpxchg128() 12 # define try_cmpxchg_freelist try_cmpxchg128 13 # endif 14 #define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg128 15 typedef u128 freelist_full_t; 16 #else /* CONFIG_64BIT */ 17 # ifdef system_has_cmpxchg64 18 # define system_has_freelist_aba() system_has_cmpxchg64() 19 # define try_cmpxchg_freelist try_cmpxchg64 20 # endif 21 #define this_cpu_try_cmpxchg_freelist this_cpu_try_cmpxchg64 22 typedef u64 freelist_full_t; 23 #endif /* CONFIG_64BIT */ 24 25 #if defined(system_has_freelist_aba) && !defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE) 26 #undef system_has_freelist_aba 27 #endif 28 29 /* 30 * Freelist pointer and counter to cmpxchg together, avoids the typical ABA 31 * problems with cmpxchg of just a pointer. 32 */ 33 typedef union { 34 struct { 35 void *freelist; 36 unsigned long counter; 37 }; 38 freelist_full_t full; 39 } freelist_aba_t; 40 41 /* Reuses the bits in struct page */ 42 struct slab { 43 unsigned long __page_flags; 44 45 #if defined(CONFIG_SLAB) 46 47 struct kmem_cache *slab_cache; 48 union { 49 struct { 50 struct list_head slab_list; 51 void *freelist; /* array of free object indexes */ 52 void *s_mem; /* first object */ 53 }; 54 struct rcu_head rcu_head; 55 }; 56 unsigned int active; 57 58 #elif defined(CONFIG_SLUB) 59 60 struct kmem_cache *slab_cache; 61 union { 62 struct { 63 union { 64 struct list_head slab_list; 65 #ifdef CONFIG_SLUB_CPU_PARTIAL 66 struct { 67 struct slab *next; 68 int slabs; /* Nr of slabs left */ 69 }; 70 #endif 71 }; 72 /* Double-word boundary */ 73 union { 74 struct { 75 void *freelist; /* first free object */ 76 union { 77 unsigned long counters; 78 struct { 79 unsigned inuse:16; 80 unsigned objects:15; 81 /* 82 * If slab debugging is enabled then the 83 * frozen bit can be reused to indicate 84 * that the slab was corrupted 85 */ 86 unsigned frozen:1; 87 }; 88 }; 89 }; 90 #ifdef system_has_freelist_aba 91 freelist_aba_t freelist_counter; 92 #endif 93 }; 94 }; 95 struct rcu_head rcu_head; 96 }; 97 unsigned int __unused; 98 99 #else 100 #error "Unexpected slab allocator configured" 101 #endif 102 103 atomic_t __page_refcount; 104 #ifdef CONFIG_MEMCG 105 unsigned long memcg_data; 106 #endif 107 }; 108 109 #define SLAB_MATCH(pg, sl) \ 110 static_assert(offsetof(struct page, pg) == offsetof(struct slab, sl)) 111 SLAB_MATCH(flags, __page_flags); 112 SLAB_MATCH(compound_head, slab_cache); /* Ensure bit 0 is clear */ 113 SLAB_MATCH(_refcount, __page_refcount); 114 #ifdef CONFIG_MEMCG 115 SLAB_MATCH(memcg_data, memcg_data); 116 #endif 117 #undef SLAB_MATCH 118 static_assert(sizeof(struct slab) <= sizeof(struct page)); 119 #if defined(system_has_freelist_aba) && defined(CONFIG_SLUB) 120 static_assert(IS_ALIGNED(offsetof(struct slab, freelist), sizeof(freelist_aba_t))); 121 #endif 122 123 /** 124 * folio_slab - Converts from folio to slab. 125 * @folio: The folio. 126 * 127 * Currently struct slab is a different representation of a folio where 128 * folio_test_slab() is true. 129 * 130 * Return: The slab which contains this folio. 131 */ 132 #define folio_slab(folio) (_Generic((folio), \ 133 const struct folio *: (const struct slab *)(folio), \ 134 struct folio *: (struct slab *)(folio))) 135 136 /** 137 * slab_folio - The folio allocated for a slab 138 * @slab: The slab. 139 * 140 * Slabs are allocated as folios that contain the individual objects and are 141 * using some fields in the first struct page of the folio - those fields are 142 * now accessed by struct slab. It is occasionally necessary to convert back to 143 * a folio in order to communicate with the rest of the mm. Please use this 144 * helper function instead of casting yourself, as the implementation may change 145 * in the future. 146 */ 147 #define slab_folio(s) (_Generic((s), \ 148 const struct slab *: (const struct folio *)s, \ 149 struct slab *: (struct folio *)s)) 150 151 /** 152 * page_slab - Converts from first struct page to slab. 153 * @p: The first (either head of compound or single) page of slab. 154 * 155 * A temporary wrapper to convert struct page to struct slab in situations where 156 * we know the page is the compound head, or single order-0 page. 157 * 158 * Long-term ideally everything would work with struct slab directly or go 159 * through folio to struct slab. 160 * 161 * Return: The slab which contains this page 162 */ 163 #define page_slab(p) (_Generic((p), \ 164 const struct page *: (const struct slab *)(p), \ 165 struct page *: (struct slab *)(p))) 166 167 /** 168 * slab_page - The first struct page allocated for a slab 169 * @slab: The slab. 170 * 171 * A convenience wrapper for converting slab to the first struct page of the 172 * underlying folio, to communicate with code not yet converted to folio or 173 * struct slab. 174 */ 175 #define slab_page(s) folio_page(slab_folio(s), 0) 176 177 /* 178 * If network-based swap is enabled, sl*b must keep track of whether pages 179 * were allocated from pfmemalloc reserves. 180 */ 181 static inline bool slab_test_pfmemalloc(const struct slab *slab) 182 { 183 return folio_test_active((struct folio *)slab_folio(slab)); 184 } 185 186 static inline void slab_set_pfmemalloc(struct slab *slab) 187 { 188 folio_set_active(slab_folio(slab)); 189 } 190 191 static inline void slab_clear_pfmemalloc(struct slab *slab) 192 { 193 folio_clear_active(slab_folio(slab)); 194 } 195 196 static inline void __slab_clear_pfmemalloc(struct slab *slab) 197 { 198 __folio_clear_active(slab_folio(slab)); 199 } 200 201 static inline void *slab_address(const struct slab *slab) 202 { 203 return folio_address(slab_folio(slab)); 204 } 205 206 static inline int slab_nid(const struct slab *slab) 207 { 208 return folio_nid(slab_folio(slab)); 209 } 210 211 static inline pg_data_t *slab_pgdat(const struct slab *slab) 212 { 213 return folio_pgdat(slab_folio(slab)); 214 } 215 216 static inline struct slab *virt_to_slab(const void *addr) 217 { 218 struct folio *folio = virt_to_folio(addr); 219 220 if (!folio_test_slab(folio)) 221 return NULL; 222 223 return folio_slab(folio); 224 } 225 226 static inline int slab_order(const struct slab *slab) 227 { 228 return folio_order((struct folio *)slab_folio(slab)); 229 } 230 231 static inline size_t slab_size(const struct slab *slab) 232 { 233 return PAGE_SIZE << slab_order(slab); 234 } 235 236 #ifdef CONFIG_SLAB 237 #include <linux/slab_def.h> 238 #endif 239 240 #ifdef CONFIG_SLUB 241 #include <linux/slub_def.h> 242 #endif 243 244 #include <linux/memcontrol.h> 245 #include <linux/fault-inject.h> 246 #include <linux/kasan.h> 247 #include <linux/kmemleak.h> 248 #include <linux/random.h> 249 #include <linux/sched/mm.h> 250 #include <linux/list_lru.h> 251 252 /* 253 * State of the slab allocator. 254 * 255 * This is used to describe the states of the allocator during bootup. 256 * Allocators use this to gradually bootstrap themselves. Most allocators 257 * have the problem that the structures used for managing slab caches are 258 * allocated from slab caches themselves. 259 */ 260 enum slab_state { 261 DOWN, /* No slab functionality yet */ 262 PARTIAL, /* SLUB: kmem_cache_node available */ 263 PARTIAL_NODE, /* SLAB: kmalloc size for node struct available */ 264 UP, /* Slab caches usable but not all extras yet */ 265 FULL /* Everything is working */ 266 }; 267 268 extern enum slab_state slab_state; 269 270 /* The slab cache mutex protects the management structures during changes */ 271 extern struct mutex slab_mutex; 272 273 /* The list of all slab caches on the system */ 274 extern struct list_head slab_caches; 275 276 /* The slab cache that manages slab cache information */ 277 extern struct kmem_cache *kmem_cache; 278 279 /* A table of kmalloc cache names and sizes */ 280 extern const struct kmalloc_info_struct { 281 const char *name[NR_KMALLOC_TYPES]; 282 unsigned int size; 283 } kmalloc_info[]; 284 285 /* Kmalloc array related functions */ 286 void setup_kmalloc_cache_index_table(void); 287 void create_kmalloc_caches(slab_flags_t); 288 289 /* Find the kmalloc slab corresponding for a certain size */ 290 struct kmem_cache *kmalloc_slab(size_t size, gfp_t flags, unsigned long caller); 291 292 void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, 293 int node, size_t orig_size, 294 unsigned long caller); 295 void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller); 296 297 gfp_t kmalloc_fix_flags(gfp_t flags); 298 299 /* Functions provided by the slab allocators */ 300 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags); 301 302 void __init new_kmalloc_cache(int idx, enum kmalloc_cache_type type, 303 slab_flags_t flags); 304 extern void create_boot_cache(struct kmem_cache *, const char *name, 305 unsigned int size, slab_flags_t flags, 306 unsigned int useroffset, unsigned int usersize); 307 308 int slab_unmergeable(struct kmem_cache *s); 309 struct kmem_cache *find_mergeable(unsigned size, unsigned align, 310 slab_flags_t flags, const char *name, void (*ctor)(void *)); 311 struct kmem_cache * 312 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, 313 slab_flags_t flags, void (*ctor)(void *)); 314 315 slab_flags_t kmem_cache_flags(unsigned int object_size, 316 slab_flags_t flags, const char *name); 317 318 static inline bool is_kmalloc_cache(struct kmem_cache *s) 319 { 320 return (s->flags & SLAB_KMALLOC); 321 } 322 323 /* Legal flag mask for kmem_cache_create(), for various configurations */ 324 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \ 325 SLAB_CACHE_DMA32 | SLAB_PANIC | \ 326 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS ) 327 328 #if defined(CONFIG_DEBUG_SLAB) 329 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) 330 #elif defined(CONFIG_SLUB_DEBUG) 331 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 332 SLAB_TRACE | SLAB_CONSISTENCY_CHECKS) 333 #else 334 #define SLAB_DEBUG_FLAGS (0) 335 #endif 336 337 #if defined(CONFIG_SLAB) 338 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \ 339 SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \ 340 SLAB_ACCOUNT | SLAB_NO_MERGE) 341 #elif defined(CONFIG_SLUB) 342 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \ 343 SLAB_TEMPORARY | SLAB_ACCOUNT | \ 344 SLAB_NO_USER_FLAGS | SLAB_KMALLOC | SLAB_NO_MERGE) 345 #else 346 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE) 347 #endif 348 349 /* Common flags available with current configuration */ 350 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS) 351 352 /* Common flags permitted for kmem_cache_create */ 353 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \ 354 SLAB_RED_ZONE | \ 355 SLAB_POISON | \ 356 SLAB_STORE_USER | \ 357 SLAB_TRACE | \ 358 SLAB_CONSISTENCY_CHECKS | \ 359 SLAB_MEM_SPREAD | \ 360 SLAB_NOLEAKTRACE | \ 361 SLAB_RECLAIM_ACCOUNT | \ 362 SLAB_TEMPORARY | \ 363 SLAB_ACCOUNT | \ 364 SLAB_KMALLOC | \ 365 SLAB_NO_MERGE | \ 366 SLAB_NO_USER_FLAGS) 367 368 bool __kmem_cache_empty(struct kmem_cache *); 369 int __kmem_cache_shutdown(struct kmem_cache *); 370 void __kmem_cache_release(struct kmem_cache *); 371 int __kmem_cache_shrink(struct kmem_cache *); 372 void slab_kmem_cache_release(struct kmem_cache *); 373 374 struct seq_file; 375 struct file; 376 377 struct slabinfo { 378 unsigned long active_objs; 379 unsigned long num_objs; 380 unsigned long active_slabs; 381 unsigned long num_slabs; 382 unsigned long shared_avail; 383 unsigned int limit; 384 unsigned int batchcount; 385 unsigned int shared; 386 unsigned int objects_per_slab; 387 unsigned int cache_order; 388 }; 389 390 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo); 391 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s); 392 ssize_t slabinfo_write(struct file *file, const char __user *buffer, 393 size_t count, loff_t *ppos); 394 395 static inline enum node_stat_item cache_vmstat_idx(struct kmem_cache *s) 396 { 397 return (s->flags & SLAB_RECLAIM_ACCOUNT) ? 398 NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B; 399 } 400 401 #ifdef CONFIG_SLUB_DEBUG 402 #ifdef CONFIG_SLUB_DEBUG_ON 403 DECLARE_STATIC_KEY_TRUE(slub_debug_enabled); 404 #else 405 DECLARE_STATIC_KEY_FALSE(slub_debug_enabled); 406 #endif 407 extern void print_tracking(struct kmem_cache *s, void *object); 408 long validate_slab_cache(struct kmem_cache *s); 409 static inline bool __slub_debug_enabled(void) 410 { 411 return static_branch_unlikely(&slub_debug_enabled); 412 } 413 #else 414 static inline void print_tracking(struct kmem_cache *s, void *object) 415 { 416 } 417 static inline bool __slub_debug_enabled(void) 418 { 419 return false; 420 } 421 #endif 422 423 /* 424 * Returns true if any of the specified slub_debug flags is enabled for the 425 * cache. Use only for flags parsed by setup_slub_debug() as it also enables 426 * the static key. 427 */ 428 static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags) 429 { 430 if (IS_ENABLED(CONFIG_SLUB_DEBUG)) 431 VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS)); 432 if (__slub_debug_enabled()) 433 return s->flags & flags; 434 return false; 435 } 436 437 #ifdef CONFIG_MEMCG_KMEM 438 /* 439 * slab_objcgs - get the object cgroups vector associated with a slab 440 * @slab: a pointer to the slab struct 441 * 442 * Returns a pointer to the object cgroups vector associated with the slab, 443 * or NULL if no such vector has been associated yet. 444 */ 445 static inline struct obj_cgroup **slab_objcgs(struct slab *slab) 446 { 447 unsigned long memcg_data = READ_ONCE(slab->memcg_data); 448 449 VM_BUG_ON_PAGE(memcg_data && !(memcg_data & MEMCG_DATA_OBJCGS), 450 slab_page(slab)); 451 VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, slab_page(slab)); 452 453 return (struct obj_cgroup **)(memcg_data & ~MEMCG_DATA_FLAGS_MASK); 454 } 455 456 int memcg_alloc_slab_cgroups(struct slab *slab, struct kmem_cache *s, 457 gfp_t gfp, bool new_slab); 458 void mod_objcg_state(struct obj_cgroup *objcg, struct pglist_data *pgdat, 459 enum node_stat_item idx, int nr); 460 461 static inline void memcg_free_slab_cgroups(struct slab *slab) 462 { 463 kfree(slab_objcgs(slab)); 464 slab->memcg_data = 0; 465 } 466 467 static inline size_t obj_full_size(struct kmem_cache *s) 468 { 469 /* 470 * For each accounted object there is an extra space which is used 471 * to store obj_cgroup membership. Charge it too. 472 */ 473 return s->size + sizeof(struct obj_cgroup *); 474 } 475 476 /* 477 * Returns false if the allocation should fail. 478 */ 479 static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, 480 struct list_lru *lru, 481 struct obj_cgroup **objcgp, 482 size_t objects, gfp_t flags) 483 { 484 struct obj_cgroup *objcg; 485 486 if (!memcg_kmem_online()) 487 return true; 488 489 if (!(flags & __GFP_ACCOUNT) && !(s->flags & SLAB_ACCOUNT)) 490 return true; 491 492 objcg = get_obj_cgroup_from_current(); 493 if (!objcg) 494 return true; 495 496 if (lru) { 497 int ret; 498 struct mem_cgroup *memcg; 499 500 memcg = get_mem_cgroup_from_objcg(objcg); 501 ret = memcg_list_lru_alloc(memcg, lru, flags); 502 css_put(&memcg->css); 503 504 if (ret) 505 goto out; 506 } 507 508 if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) 509 goto out; 510 511 *objcgp = objcg; 512 return true; 513 out: 514 obj_cgroup_put(objcg); 515 return false; 516 } 517 518 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, 519 struct obj_cgroup *objcg, 520 gfp_t flags, size_t size, 521 void **p) 522 { 523 struct slab *slab; 524 unsigned long off; 525 size_t i; 526 527 if (!memcg_kmem_online() || !objcg) 528 return; 529 530 for (i = 0; i < size; i++) { 531 if (likely(p[i])) { 532 slab = virt_to_slab(p[i]); 533 534 if (!slab_objcgs(slab) && 535 memcg_alloc_slab_cgroups(slab, s, flags, 536 false)) { 537 obj_cgroup_uncharge(objcg, obj_full_size(s)); 538 continue; 539 } 540 541 off = obj_to_index(s, slab, p[i]); 542 obj_cgroup_get(objcg); 543 slab_objcgs(slab)[off] = objcg; 544 mod_objcg_state(objcg, slab_pgdat(slab), 545 cache_vmstat_idx(s), obj_full_size(s)); 546 } else { 547 obj_cgroup_uncharge(objcg, obj_full_size(s)); 548 } 549 } 550 obj_cgroup_put(objcg); 551 } 552 553 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, 554 void **p, int objects) 555 { 556 struct obj_cgroup **objcgs; 557 int i; 558 559 if (!memcg_kmem_online()) 560 return; 561 562 objcgs = slab_objcgs(slab); 563 if (!objcgs) 564 return; 565 566 for (i = 0; i < objects; i++) { 567 struct obj_cgroup *objcg; 568 unsigned int off; 569 570 off = obj_to_index(s, slab, p[i]); 571 objcg = objcgs[off]; 572 if (!objcg) 573 continue; 574 575 objcgs[off] = NULL; 576 obj_cgroup_uncharge(objcg, obj_full_size(s)); 577 mod_objcg_state(objcg, slab_pgdat(slab), cache_vmstat_idx(s), 578 -obj_full_size(s)); 579 obj_cgroup_put(objcg); 580 } 581 } 582 583 #else /* CONFIG_MEMCG_KMEM */ 584 static inline struct obj_cgroup **slab_objcgs(struct slab *slab) 585 { 586 return NULL; 587 } 588 589 static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr) 590 { 591 return NULL; 592 } 593 594 static inline int memcg_alloc_slab_cgroups(struct slab *slab, 595 struct kmem_cache *s, gfp_t gfp, 596 bool new_slab) 597 { 598 return 0; 599 } 600 601 static inline void memcg_free_slab_cgroups(struct slab *slab) 602 { 603 } 604 605 static inline bool memcg_slab_pre_alloc_hook(struct kmem_cache *s, 606 struct list_lru *lru, 607 struct obj_cgroup **objcgp, 608 size_t objects, gfp_t flags) 609 { 610 return true; 611 } 612 613 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, 614 struct obj_cgroup *objcg, 615 gfp_t flags, size_t size, 616 void **p) 617 { 618 } 619 620 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct slab *slab, 621 void **p, int objects) 622 { 623 } 624 #endif /* CONFIG_MEMCG_KMEM */ 625 626 static inline struct kmem_cache *virt_to_cache(const void *obj) 627 { 628 struct slab *slab; 629 630 slab = virt_to_slab(obj); 631 if (WARN_ONCE(!slab, "%s: Object is not a Slab page!\n", 632 __func__)) 633 return NULL; 634 return slab->slab_cache; 635 } 636 637 static __always_inline void account_slab(struct slab *slab, int order, 638 struct kmem_cache *s, gfp_t gfp) 639 { 640 if (memcg_kmem_online() && (s->flags & SLAB_ACCOUNT)) 641 memcg_alloc_slab_cgroups(slab, s, gfp, true); 642 643 mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), 644 PAGE_SIZE << order); 645 } 646 647 static __always_inline void unaccount_slab(struct slab *slab, int order, 648 struct kmem_cache *s) 649 { 650 if (memcg_kmem_online()) 651 memcg_free_slab_cgroups(slab); 652 653 mod_node_page_state(slab_pgdat(slab), cache_vmstat_idx(s), 654 -(PAGE_SIZE << order)); 655 } 656 657 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x) 658 { 659 struct kmem_cache *cachep; 660 661 if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && 662 !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) 663 return s; 664 665 cachep = virt_to_cache(x); 666 if (WARN(cachep && cachep != s, 667 "%s: Wrong slab cache. %s but object is from %s\n", 668 __func__, s->name, cachep->name)) 669 print_tracking(cachep, x); 670 return cachep; 671 } 672 673 void free_large_kmalloc(struct folio *folio, void *object); 674 675 size_t __ksize(const void *objp); 676 677 static inline size_t slab_ksize(const struct kmem_cache *s) 678 { 679 #ifndef CONFIG_SLUB 680 return s->object_size; 681 682 #else /* CONFIG_SLUB */ 683 # ifdef CONFIG_SLUB_DEBUG 684 /* 685 * Debugging requires use of the padding between object 686 * and whatever may come after it. 687 */ 688 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) 689 return s->object_size; 690 # endif 691 if (s->flags & SLAB_KASAN) 692 return s->object_size; 693 /* 694 * If we have the need to store the freelist pointer 695 * back there or track user information then we can 696 * only use the space before that information. 697 */ 698 if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER)) 699 return s->inuse; 700 /* 701 * Else we can use all the padding etc for the allocation 702 */ 703 return s->size; 704 #endif 705 } 706 707 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, 708 struct list_lru *lru, 709 struct obj_cgroup **objcgp, 710 size_t size, gfp_t flags) 711 { 712 flags &= gfp_allowed_mask; 713 714 might_alloc(flags); 715 716 if (should_failslab(s, flags)) 717 return NULL; 718 719 if (!memcg_slab_pre_alloc_hook(s, lru, objcgp, size, flags)) 720 return NULL; 721 722 return s; 723 } 724 725 static inline void slab_post_alloc_hook(struct kmem_cache *s, 726 struct obj_cgroup *objcg, gfp_t flags, 727 size_t size, void **p, bool init, 728 unsigned int orig_size) 729 { 730 unsigned int zero_size = s->object_size; 731 bool kasan_init = init; 732 size_t i; 733 734 flags &= gfp_allowed_mask; 735 736 /* 737 * For kmalloc object, the allocated memory size(object_size) is likely 738 * larger than the requested size(orig_size). If redzone check is 739 * enabled for the extra space, don't zero it, as it will be redzoned 740 * soon. The redzone operation for this extra space could be seen as a 741 * replacement of current poisoning under certain debug option, and 742 * won't break other sanity checks. 743 */ 744 if (kmem_cache_debug_flags(s, SLAB_STORE_USER | SLAB_RED_ZONE) && 745 (s->flags & SLAB_KMALLOC)) 746 zero_size = orig_size; 747 748 /* 749 * When slub_debug is enabled, avoid memory initialization integrated 750 * into KASAN and instead zero out the memory via the memset below with 751 * the proper size. Otherwise, KASAN might overwrite SLUB redzones and 752 * cause false-positive reports. This does not lead to a performance 753 * penalty on production builds, as slub_debug is not intended to be 754 * enabled there. 755 */ 756 if (__slub_debug_enabled()) 757 kasan_init = false; 758 759 /* 760 * As memory initialization might be integrated into KASAN, 761 * kasan_slab_alloc and initialization memset must be 762 * kept together to avoid discrepancies in behavior. 763 * 764 * As p[i] might get tagged, memset and kmemleak hook come after KASAN. 765 */ 766 for (i = 0; i < size; i++) { 767 p[i] = kasan_slab_alloc(s, p[i], flags, kasan_init); 768 if (p[i] && init && (!kasan_init || !kasan_has_integrated_init())) 769 memset(p[i], 0, zero_size); 770 kmemleak_alloc_recursive(p[i], s->object_size, 1, 771 s->flags, flags); 772 kmsan_slab_alloc(s, p[i], flags); 773 } 774 775 memcg_slab_post_alloc_hook(s, objcg, flags, size, p); 776 } 777 778 /* 779 * The slab lists for all objects. 780 */ 781 struct kmem_cache_node { 782 #ifdef CONFIG_SLAB 783 raw_spinlock_t list_lock; 784 struct list_head slabs_partial; /* partial list first, better asm code */ 785 struct list_head slabs_full; 786 struct list_head slabs_free; 787 unsigned long total_slabs; /* length of all slab lists */ 788 unsigned long free_slabs; /* length of free slab list only */ 789 unsigned long free_objects; 790 unsigned int free_limit; 791 unsigned int colour_next; /* Per-node cache coloring */ 792 struct array_cache *shared; /* shared per node */ 793 struct alien_cache **alien; /* on other nodes */ 794 unsigned long next_reap; /* updated without locking */ 795 int free_touched; /* updated without locking */ 796 #endif 797 798 #ifdef CONFIG_SLUB 799 spinlock_t list_lock; 800 unsigned long nr_partial; 801 struct list_head partial; 802 #ifdef CONFIG_SLUB_DEBUG 803 atomic_long_t nr_slabs; 804 atomic_long_t total_objects; 805 struct list_head full; 806 #endif 807 #endif 808 809 }; 810 811 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) 812 { 813 return s->node[node]; 814 } 815 816 /* 817 * Iterator over all nodes. The body will be executed for each node that has 818 * a kmem_cache_node structure allocated (which is true for all online nodes) 819 */ 820 #define for_each_kmem_cache_node(__s, __node, __n) \ 821 for (__node = 0; __node < nr_node_ids; __node++) \ 822 if ((__n = get_node(__s, __node))) 823 824 825 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 826 void dump_unreclaimable_slab(void); 827 #else 828 static inline void dump_unreclaimable_slab(void) 829 { 830 } 831 #endif 832 833 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr); 834 835 #ifdef CONFIG_SLAB_FREELIST_RANDOM 836 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 837 gfp_t gfp); 838 void cache_random_seq_destroy(struct kmem_cache *cachep); 839 #else 840 static inline int cache_random_seq_create(struct kmem_cache *cachep, 841 unsigned int count, gfp_t gfp) 842 { 843 return 0; 844 } 845 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { } 846 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 847 848 static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) 849 { 850 if (static_branch_maybe(CONFIG_INIT_ON_ALLOC_DEFAULT_ON, 851 &init_on_alloc)) { 852 if (c->ctor) 853 return false; 854 if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) 855 return flags & __GFP_ZERO; 856 return true; 857 } 858 return flags & __GFP_ZERO; 859 } 860 861 static inline bool slab_want_init_on_free(struct kmem_cache *c) 862 { 863 if (static_branch_maybe(CONFIG_INIT_ON_FREE_DEFAULT_ON, 864 &init_on_free)) 865 return !(c->ctor || 866 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))); 867 return false; 868 } 869 870 #if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG) 871 void debugfs_slab_release(struct kmem_cache *); 872 #else 873 static inline void debugfs_slab_release(struct kmem_cache *s) { } 874 #endif 875 876 #ifdef CONFIG_PRINTK 877 #define KS_ADDRS_COUNT 16 878 struct kmem_obj_info { 879 void *kp_ptr; 880 struct slab *kp_slab; 881 void *kp_objp; 882 unsigned long kp_data_offset; 883 struct kmem_cache *kp_slab_cache; 884 void *kp_ret; 885 void *kp_stack[KS_ADDRS_COUNT]; 886 void *kp_free_stack[KS_ADDRS_COUNT]; 887 }; 888 void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab); 889 #endif 890 891 void __check_heap_object(const void *ptr, unsigned long n, 892 const struct slab *slab, bool to_user); 893 894 #ifdef CONFIG_SLUB_DEBUG 895 void skip_orig_size_check(struct kmem_cache *s, const void *object); 896 #endif 897 898 #endif /* MM_SLAB_H */ 899