1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef MM_SLAB_H 3 #define MM_SLAB_H 4 /* 5 * Internal slab definitions 6 */ 7 8 #ifdef CONFIG_SLOB 9 /* 10 * Common fields provided in kmem_cache by all slab allocators 11 * This struct is either used directly by the allocator (SLOB) 12 * or the allocator must include definitions for all fields 13 * provided in kmem_cache_common in their definition of kmem_cache. 14 * 15 * Once we can do anonymous structs (C11 standard) we could put a 16 * anonymous struct definition in these allocators so that the 17 * separate allocations in the kmem_cache structure of SLAB and 18 * SLUB is no longer needed. 19 */ 20 struct kmem_cache { 21 unsigned int object_size;/* The original size of the object */ 22 unsigned int size; /* The aligned/padded/added on size */ 23 unsigned int align; /* Alignment as calculated */ 24 slab_flags_t flags; /* Active flags on the slab */ 25 unsigned int useroffset;/* Usercopy region offset */ 26 unsigned int usersize; /* Usercopy region size */ 27 const char *name; /* Slab name for sysfs */ 28 int refcount; /* Use counter */ 29 void (*ctor)(void *); /* Called on object slot creation */ 30 struct list_head list; /* List of all slab caches on the system */ 31 }; 32 33 #endif /* CONFIG_SLOB */ 34 35 #ifdef CONFIG_SLAB 36 #include <linux/slab_def.h> 37 #endif 38 39 #ifdef CONFIG_SLUB 40 #include <linux/slub_def.h> 41 #endif 42 43 #include <linux/memcontrol.h> 44 #include <linux/fault-inject.h> 45 #include <linux/kasan.h> 46 #include <linux/kmemleak.h> 47 #include <linux/random.h> 48 #include <linux/sched/mm.h> 49 #include <linux/kmemleak.h> 50 51 /* 52 * State of the slab allocator. 53 * 54 * This is used to describe the states of the allocator during bootup. 55 * Allocators use this to gradually bootstrap themselves. Most allocators 56 * have the problem that the structures used for managing slab caches are 57 * allocated from slab caches themselves. 58 */ 59 enum slab_state { 60 DOWN, /* No slab functionality yet */ 61 PARTIAL, /* SLUB: kmem_cache_node available */ 62 PARTIAL_NODE, /* SLAB: kmalloc size for node struct available */ 63 UP, /* Slab caches usable but not all extras yet */ 64 FULL /* Everything is working */ 65 }; 66 67 extern enum slab_state slab_state; 68 69 /* The slab cache mutex protects the management structures during changes */ 70 extern struct mutex slab_mutex; 71 72 /* The list of all slab caches on the system */ 73 extern struct list_head slab_caches; 74 75 /* The slab cache that manages slab cache information */ 76 extern struct kmem_cache *kmem_cache; 77 78 /* A table of kmalloc cache names and sizes */ 79 extern const struct kmalloc_info_struct { 80 const char *name[NR_KMALLOC_TYPES]; 81 unsigned int size; 82 } kmalloc_info[]; 83 84 #ifndef CONFIG_SLOB 85 /* Kmalloc array related functions */ 86 void setup_kmalloc_cache_index_table(void); 87 void create_kmalloc_caches(slab_flags_t); 88 89 /* Find the kmalloc slab corresponding for a certain size */ 90 struct kmem_cache *kmalloc_slab(size_t, gfp_t); 91 #endif 92 93 gfp_t kmalloc_fix_flags(gfp_t flags); 94 95 /* Functions provided by the slab allocators */ 96 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags); 97 98 struct kmem_cache *create_kmalloc_cache(const char *name, unsigned int size, 99 slab_flags_t flags, unsigned int useroffset, 100 unsigned int usersize); 101 extern void create_boot_cache(struct kmem_cache *, const char *name, 102 unsigned int size, slab_flags_t flags, 103 unsigned int useroffset, unsigned int usersize); 104 105 int slab_unmergeable(struct kmem_cache *s); 106 struct kmem_cache *find_mergeable(unsigned size, unsigned align, 107 slab_flags_t flags, const char *name, void (*ctor)(void *)); 108 #ifndef CONFIG_SLOB 109 struct kmem_cache * 110 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, 111 slab_flags_t flags, void (*ctor)(void *)); 112 113 slab_flags_t kmem_cache_flags(unsigned int object_size, 114 slab_flags_t flags, const char *name, 115 void (*ctor)(void *)); 116 #else 117 static inline struct kmem_cache * 118 __kmem_cache_alias(const char *name, unsigned int size, unsigned int align, 119 slab_flags_t flags, void (*ctor)(void *)) 120 { return NULL; } 121 122 static inline slab_flags_t kmem_cache_flags(unsigned int object_size, 123 slab_flags_t flags, const char *name, 124 void (*ctor)(void *)) 125 { 126 return flags; 127 } 128 #endif 129 130 131 /* Legal flag mask for kmem_cache_create(), for various configurations */ 132 #define SLAB_CORE_FLAGS (SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA | \ 133 SLAB_CACHE_DMA32 | SLAB_PANIC | \ 134 SLAB_TYPESAFE_BY_RCU | SLAB_DEBUG_OBJECTS ) 135 136 #if defined(CONFIG_DEBUG_SLAB) 137 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER) 138 #elif defined(CONFIG_SLUB_DEBUG) 139 #define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \ 140 SLAB_TRACE | SLAB_CONSISTENCY_CHECKS) 141 #else 142 #define SLAB_DEBUG_FLAGS (0) 143 #endif 144 145 #if defined(CONFIG_SLAB) 146 #define SLAB_CACHE_FLAGS (SLAB_MEM_SPREAD | SLAB_NOLEAKTRACE | \ 147 SLAB_RECLAIM_ACCOUNT | SLAB_TEMPORARY | \ 148 SLAB_ACCOUNT) 149 #elif defined(CONFIG_SLUB) 150 #define SLAB_CACHE_FLAGS (SLAB_NOLEAKTRACE | SLAB_RECLAIM_ACCOUNT | \ 151 SLAB_TEMPORARY | SLAB_ACCOUNT) 152 #else 153 #define SLAB_CACHE_FLAGS (0) 154 #endif 155 156 /* Common flags available with current configuration */ 157 #define CACHE_CREATE_MASK (SLAB_CORE_FLAGS | SLAB_DEBUG_FLAGS | SLAB_CACHE_FLAGS) 158 159 /* Common flags permitted for kmem_cache_create */ 160 #define SLAB_FLAGS_PERMITTED (SLAB_CORE_FLAGS | \ 161 SLAB_RED_ZONE | \ 162 SLAB_POISON | \ 163 SLAB_STORE_USER | \ 164 SLAB_TRACE | \ 165 SLAB_CONSISTENCY_CHECKS | \ 166 SLAB_MEM_SPREAD | \ 167 SLAB_NOLEAKTRACE | \ 168 SLAB_RECLAIM_ACCOUNT | \ 169 SLAB_TEMPORARY | \ 170 SLAB_ACCOUNT) 171 172 bool __kmem_cache_empty(struct kmem_cache *); 173 int __kmem_cache_shutdown(struct kmem_cache *); 174 void __kmem_cache_release(struct kmem_cache *); 175 int __kmem_cache_shrink(struct kmem_cache *); 176 void slab_kmem_cache_release(struct kmem_cache *); 177 178 struct seq_file; 179 struct file; 180 181 struct slabinfo { 182 unsigned long active_objs; 183 unsigned long num_objs; 184 unsigned long active_slabs; 185 unsigned long num_slabs; 186 unsigned long shared_avail; 187 unsigned int limit; 188 unsigned int batchcount; 189 unsigned int shared; 190 unsigned int objects_per_slab; 191 unsigned int cache_order; 192 }; 193 194 void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo); 195 void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s); 196 ssize_t slabinfo_write(struct file *file, const char __user *buffer, 197 size_t count, loff_t *ppos); 198 199 /* 200 * Generic implementation of bulk operations 201 * These are useful for situations in which the allocator cannot 202 * perform optimizations. In that case segments of the object listed 203 * may be allocated or freed using these operations. 204 */ 205 void __kmem_cache_free_bulk(struct kmem_cache *, size_t, void **); 206 int __kmem_cache_alloc_bulk(struct kmem_cache *, gfp_t, size_t, void **); 207 208 static inline int cache_vmstat_idx(struct kmem_cache *s) 209 { 210 return (s->flags & SLAB_RECLAIM_ACCOUNT) ? 211 NR_SLAB_RECLAIMABLE_B : NR_SLAB_UNRECLAIMABLE_B; 212 } 213 214 #ifdef CONFIG_SLUB_DEBUG 215 #ifdef CONFIG_SLUB_DEBUG_ON 216 DECLARE_STATIC_KEY_TRUE(slub_debug_enabled); 217 #else 218 DECLARE_STATIC_KEY_FALSE(slub_debug_enabled); 219 #endif 220 extern void print_tracking(struct kmem_cache *s, void *object); 221 #else 222 static inline void print_tracking(struct kmem_cache *s, void *object) 223 { 224 } 225 #endif 226 227 /* 228 * Returns true if any of the specified slub_debug flags is enabled for the 229 * cache. Use only for flags parsed by setup_slub_debug() as it also enables 230 * the static key. 231 */ 232 static inline bool kmem_cache_debug_flags(struct kmem_cache *s, slab_flags_t flags) 233 { 234 #ifdef CONFIG_SLUB_DEBUG 235 VM_WARN_ON_ONCE(!(flags & SLAB_DEBUG_FLAGS)); 236 if (static_branch_unlikely(&slub_debug_enabled)) 237 return s->flags & flags; 238 #endif 239 return false; 240 } 241 242 #ifdef CONFIG_MEMCG_KMEM 243 static inline struct obj_cgroup **page_obj_cgroups(struct page *page) 244 { 245 /* 246 * page->mem_cgroup and page->obj_cgroups are sharing the same 247 * space. To distinguish between them in case we don't know for sure 248 * that the page is a slab page (e.g. page_cgroup_ino()), let's 249 * always set the lowest bit of obj_cgroups. 250 */ 251 return (struct obj_cgroup **) 252 ((unsigned long)page->obj_cgroups & ~0x1UL); 253 } 254 255 static inline bool page_has_obj_cgroups(struct page *page) 256 { 257 return ((unsigned long)page->obj_cgroups & 0x1UL); 258 } 259 260 int memcg_alloc_page_obj_cgroups(struct page *page, struct kmem_cache *s, 261 gfp_t gfp); 262 263 static inline void memcg_free_page_obj_cgroups(struct page *page) 264 { 265 kfree(page_obj_cgroups(page)); 266 page->obj_cgroups = NULL; 267 } 268 269 static inline size_t obj_full_size(struct kmem_cache *s) 270 { 271 /* 272 * For each accounted object there is an extra space which is used 273 * to store obj_cgroup membership. Charge it too. 274 */ 275 return s->size + sizeof(struct obj_cgroup *); 276 } 277 278 static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s, 279 size_t objects, 280 gfp_t flags) 281 { 282 struct obj_cgroup *objcg; 283 284 if (memcg_kmem_bypass()) 285 return NULL; 286 287 objcg = get_obj_cgroup_from_current(); 288 if (!objcg) 289 return NULL; 290 291 if (obj_cgroup_charge(objcg, flags, objects * obj_full_size(s))) { 292 obj_cgroup_put(objcg); 293 return NULL; 294 } 295 296 return objcg; 297 } 298 299 static inline void mod_objcg_state(struct obj_cgroup *objcg, 300 struct pglist_data *pgdat, 301 int idx, int nr) 302 { 303 struct mem_cgroup *memcg; 304 struct lruvec *lruvec; 305 306 rcu_read_lock(); 307 memcg = obj_cgroup_memcg(objcg); 308 lruvec = mem_cgroup_lruvec(memcg, pgdat); 309 mod_memcg_lruvec_state(lruvec, idx, nr); 310 rcu_read_unlock(); 311 } 312 313 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, 314 struct obj_cgroup *objcg, 315 gfp_t flags, size_t size, 316 void **p) 317 { 318 struct page *page; 319 unsigned long off; 320 size_t i; 321 322 if (!objcg) 323 return; 324 325 flags &= ~__GFP_ACCOUNT; 326 for (i = 0; i < size; i++) { 327 if (likely(p[i])) { 328 page = virt_to_head_page(p[i]); 329 330 if (!page_has_obj_cgroups(page) && 331 memcg_alloc_page_obj_cgroups(page, s, flags)) { 332 obj_cgroup_uncharge(objcg, obj_full_size(s)); 333 continue; 334 } 335 336 off = obj_to_index(s, page, p[i]); 337 obj_cgroup_get(objcg); 338 page_obj_cgroups(page)[off] = objcg; 339 mod_objcg_state(objcg, page_pgdat(page), 340 cache_vmstat_idx(s), obj_full_size(s)); 341 } else { 342 obj_cgroup_uncharge(objcg, obj_full_size(s)); 343 } 344 } 345 obj_cgroup_put(objcg); 346 } 347 348 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page, 349 void *p) 350 { 351 struct obj_cgroup *objcg; 352 unsigned int off; 353 354 if (!memcg_kmem_enabled()) 355 return; 356 357 if (!page_has_obj_cgroups(page)) 358 return; 359 360 off = obj_to_index(s, page, p); 361 objcg = page_obj_cgroups(page)[off]; 362 page_obj_cgroups(page)[off] = NULL; 363 364 if (!objcg) 365 return; 366 367 obj_cgroup_uncharge(objcg, obj_full_size(s)); 368 mod_objcg_state(objcg, page_pgdat(page), cache_vmstat_idx(s), 369 -obj_full_size(s)); 370 371 obj_cgroup_put(objcg); 372 } 373 374 #else /* CONFIG_MEMCG_KMEM */ 375 static inline bool page_has_obj_cgroups(struct page *page) 376 { 377 return false; 378 } 379 380 static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr) 381 { 382 return NULL; 383 } 384 385 static inline int memcg_alloc_page_obj_cgroups(struct page *page, 386 struct kmem_cache *s, gfp_t gfp) 387 { 388 return 0; 389 } 390 391 static inline void memcg_free_page_obj_cgroups(struct page *page) 392 { 393 } 394 395 static inline struct obj_cgroup *memcg_slab_pre_alloc_hook(struct kmem_cache *s, 396 size_t objects, 397 gfp_t flags) 398 { 399 return NULL; 400 } 401 402 static inline void memcg_slab_post_alloc_hook(struct kmem_cache *s, 403 struct obj_cgroup *objcg, 404 gfp_t flags, size_t size, 405 void **p) 406 { 407 } 408 409 static inline void memcg_slab_free_hook(struct kmem_cache *s, struct page *page, 410 void *p) 411 { 412 } 413 #endif /* CONFIG_MEMCG_KMEM */ 414 415 static inline struct kmem_cache *virt_to_cache(const void *obj) 416 { 417 struct page *page; 418 419 page = virt_to_head_page(obj); 420 if (WARN_ONCE(!PageSlab(page), "%s: Object is not a Slab page!\n", 421 __func__)) 422 return NULL; 423 return page->slab_cache; 424 } 425 426 static __always_inline void account_slab_page(struct page *page, int order, 427 struct kmem_cache *s) 428 { 429 mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s), 430 PAGE_SIZE << order); 431 } 432 433 static __always_inline void unaccount_slab_page(struct page *page, int order, 434 struct kmem_cache *s) 435 { 436 if (memcg_kmem_enabled()) 437 memcg_free_page_obj_cgroups(page); 438 439 mod_node_page_state(page_pgdat(page), cache_vmstat_idx(s), 440 -(PAGE_SIZE << order)); 441 } 442 443 static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x) 444 { 445 struct kmem_cache *cachep; 446 447 if (!IS_ENABLED(CONFIG_SLAB_FREELIST_HARDENED) && 448 !kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) 449 return s; 450 451 cachep = virt_to_cache(x); 452 if (WARN(cachep && cachep != s, 453 "%s: Wrong slab cache. %s but object is from %s\n", 454 __func__, s->name, cachep->name)) 455 print_tracking(cachep, x); 456 return cachep; 457 } 458 459 static inline size_t slab_ksize(const struct kmem_cache *s) 460 { 461 #ifndef CONFIG_SLUB 462 return s->object_size; 463 464 #else /* CONFIG_SLUB */ 465 # ifdef CONFIG_SLUB_DEBUG 466 /* 467 * Debugging requires use of the padding between object 468 * and whatever may come after it. 469 */ 470 if (s->flags & (SLAB_RED_ZONE | SLAB_POISON)) 471 return s->object_size; 472 # endif 473 if (s->flags & SLAB_KASAN) 474 return s->object_size; 475 /* 476 * If we have the need to store the freelist pointer 477 * back there or track user information then we can 478 * only use the space before that information. 479 */ 480 if (s->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_STORE_USER)) 481 return s->inuse; 482 /* 483 * Else we can use all the padding etc for the allocation 484 */ 485 return s->size; 486 #endif 487 } 488 489 static inline struct kmem_cache *slab_pre_alloc_hook(struct kmem_cache *s, 490 struct obj_cgroup **objcgp, 491 size_t size, gfp_t flags) 492 { 493 flags &= gfp_allowed_mask; 494 495 fs_reclaim_acquire(flags); 496 fs_reclaim_release(flags); 497 498 might_sleep_if(gfpflags_allow_blocking(flags)); 499 500 if (should_failslab(s, flags)) 501 return NULL; 502 503 if (memcg_kmem_enabled() && 504 ((flags & __GFP_ACCOUNT) || (s->flags & SLAB_ACCOUNT))) 505 *objcgp = memcg_slab_pre_alloc_hook(s, size, flags); 506 507 return s; 508 } 509 510 static inline void slab_post_alloc_hook(struct kmem_cache *s, 511 struct obj_cgroup *objcg, 512 gfp_t flags, size_t size, void **p) 513 { 514 size_t i; 515 516 flags &= gfp_allowed_mask; 517 for (i = 0; i < size; i++) { 518 p[i] = kasan_slab_alloc(s, p[i], flags); 519 /* As p[i] might get tagged, call kmemleak hook after KASAN. */ 520 kmemleak_alloc_recursive(p[i], s->object_size, 1, 521 s->flags, flags); 522 } 523 524 if (memcg_kmem_enabled()) 525 memcg_slab_post_alloc_hook(s, objcg, flags, size, p); 526 } 527 528 #ifndef CONFIG_SLOB 529 /* 530 * The slab lists for all objects. 531 */ 532 struct kmem_cache_node { 533 spinlock_t list_lock; 534 535 #ifdef CONFIG_SLAB 536 struct list_head slabs_partial; /* partial list first, better asm code */ 537 struct list_head slabs_full; 538 struct list_head slabs_free; 539 unsigned long total_slabs; /* length of all slab lists */ 540 unsigned long free_slabs; /* length of free slab list only */ 541 unsigned long free_objects; 542 unsigned int free_limit; 543 unsigned int colour_next; /* Per-node cache coloring */ 544 struct array_cache *shared; /* shared per node */ 545 struct alien_cache **alien; /* on other nodes */ 546 unsigned long next_reap; /* updated without locking */ 547 int free_touched; /* updated without locking */ 548 #endif 549 550 #ifdef CONFIG_SLUB 551 unsigned long nr_partial; 552 struct list_head partial; 553 #ifdef CONFIG_SLUB_DEBUG 554 atomic_long_t nr_slabs; 555 atomic_long_t total_objects; 556 struct list_head full; 557 #endif 558 #endif 559 560 }; 561 562 static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node) 563 { 564 return s->node[node]; 565 } 566 567 /* 568 * Iterator over all nodes. The body will be executed for each node that has 569 * a kmem_cache_node structure allocated (which is true for all online nodes) 570 */ 571 #define for_each_kmem_cache_node(__s, __node, __n) \ 572 for (__node = 0; __node < nr_node_ids; __node++) \ 573 if ((__n = get_node(__s, __node))) 574 575 #endif 576 577 void *slab_start(struct seq_file *m, loff_t *pos); 578 void *slab_next(struct seq_file *m, void *p, loff_t *pos); 579 void slab_stop(struct seq_file *m, void *p); 580 int memcg_slab_show(struct seq_file *m, void *p); 581 582 #if defined(CONFIG_SLAB) || defined(CONFIG_SLUB_DEBUG) 583 void dump_unreclaimable_slab(void); 584 #else 585 static inline void dump_unreclaimable_slab(void) 586 { 587 } 588 #endif 589 590 void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr); 591 592 #ifdef CONFIG_SLAB_FREELIST_RANDOM 593 int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count, 594 gfp_t gfp); 595 void cache_random_seq_destroy(struct kmem_cache *cachep); 596 #else 597 static inline int cache_random_seq_create(struct kmem_cache *cachep, 598 unsigned int count, gfp_t gfp) 599 { 600 return 0; 601 } 602 static inline void cache_random_seq_destroy(struct kmem_cache *cachep) { } 603 #endif /* CONFIG_SLAB_FREELIST_RANDOM */ 604 605 static inline bool slab_want_init_on_alloc(gfp_t flags, struct kmem_cache *c) 606 { 607 if (static_branch_unlikely(&init_on_alloc)) { 608 if (c->ctor) 609 return false; 610 if (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) 611 return flags & __GFP_ZERO; 612 return true; 613 } 614 return flags & __GFP_ZERO; 615 } 616 617 static inline bool slab_want_init_on_free(struct kmem_cache *c) 618 { 619 if (static_branch_unlikely(&init_on_free)) 620 return !(c->ctor || 621 (c->flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON))); 622 return false; 623 } 624 625 #endif /* MM_SLAB_H */ 626