root/mm/slob.c

DEFINITIONS

1. slob_page_free
2. set_slob_page_free
3. clear_slob_page_free
4. set_slob
5. slob_units
6. slob_next
7. slob_last
8. slob_new_pages
9. slob_free_pages
10. slob_page_alloc
11. slob_alloc
12. slob_free
13. __do_kmalloc_node
14. __kmalloc
15. __kmalloc_track_caller
16. __kmalloc_node_track_caller
17. kfree
18. __ksize
19. __kmem_cache_create
20. slob_alloc_node
21. kmem_cache_alloc
22. __kmalloc_node
23. kmem_cache_alloc_node
24. __kmem_cache_free
25. kmem_rcu_free
26. kmem_cache_free
27. kmem_cache_free_bulk
28. kmem_cache_alloc_bulk
29. __kmem_cache_shutdown
30. __kmem_cache_release
31. __kmem_cache_shrink
32. kmem_cache_init
33. kmem_cache_init_late

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * SLOB Allocator: Simple List Of Blocks
   4  *
   5  * Matt Mackall <mpm@selenic.com> 12/30/03
   6  *
   7  * NUMA support by Paul Mundt, 2007.
   8  *
   9  * How SLOB works:
  10  *
  11  * The core of SLOB is a traditional K&R style heap allocator, with
  12  * support for returning aligned objects. The granularity of this
  13  * allocator is as little as 2 bytes, however typically most architectures
  14  * will require 4 bytes on 32-bit and 8 bytes on 64-bit.
  15  *
  16  * The slob heap is a set of linked list of pages from alloc_pages(),
  17  * and within each page, there is a singly-linked list of free blocks
  18  * (slob_t). The heap is grown on demand. To reduce fragmentation,
  19  * heap pages are segregated into three lists, with objects less than
  20  * 256 bytes, objects less than 1024 bytes, and all other objects.
  21  *
  22  * Allocation from heap involves first searching for a page with
  23  * sufficient free blocks (using a next-fit-like approach) followed by
  24  * a first-fit scan of the page. Deallocation inserts objects back
  25  * into the free list in address order, so this is effectively an
  26  * address-ordered first fit.
  27  *
  28  * Above this is an implementation of kmalloc/kfree. Blocks returned
  29  * from kmalloc are prepended with a 4-byte header with the kmalloc size.
  30  * If kmalloc is asked for objects of PAGE_SIZE or larger, it calls
  31  * alloc_pages() directly, allocating compound pages so the page order
  32  * does not have to be separately tracked.
  33  * These objects are detected in kfree() because PageSlab()
  34  * is false for them.
  35  *
  36  * SLAB is emulated on top of SLOB by simply calling constructors and
  37  * destructors for every SLAB allocation. Objects are returned with the
  38  * 4-byte alignment unless the SLAB_HWCACHE_ALIGN flag is set, in which
  39  * case the low-level allocator will fragment blocks to create the proper
  40  * alignment. Again, objects of page-size or greater are allocated by
  41  * calling alloc_pages(). As SLAB objects know their size, no separate
  42  * size bookkeeping is necessary and there is essentially no allocation
  43  * space overhead, and compound pages aren't needed for multi-page
  44  * allocations.
  45  *
  46  * NUMA support in SLOB is fairly simplistic, pushing most of the real
  47  * logic down to the page allocator, and simply doing the node accounting
  48  * on the upper levels. In the event that a node id is explicitly
  49  * provided, __alloc_pages_node() with the specified node id is used
  50  * instead. The common case (or when the node id isn't explicitly provided)
  51  * will default to the current node, as per numa_node_id().
  52  *
  53  * Node aware pages are still inserted in to the global freelist, and
  54  * these are scanned for by matching against the node id encoded in the
  55  * page flags. As a result, block allocations that can be satisfied from
  56  * the freelist will only be done so on pages residing on the same node,
  57  * in order to prevent random node placement.
  58  */
  59 
  60 #include <linux/kernel.h>
  61 #include <linux/slab.h>
  62 
  63 #include <linux/mm.h>
  64 #include <linux/swap.h> /* struct reclaim_state */
  65 #include <linux/cache.h>
  66 #include <linux/init.h>
  67 #include <linux/export.h>
  68 #include <linux/rcupdate.h>
  69 #include <linux/list.h>
  70 #include <linux/kmemleak.h>
  71 
  72 #include <trace/events/kmem.h>
  73 
  74 #include <linux/atomic.h>
  75 
  76 #include "slab.h"
  77 /*
  78  * slob_block has a field 'units', which indicates size of block if +ve,
  79  * or offset of next block if -ve (in SLOB_UNITs).
  80  *
  81  * Free blocks of size 1 unit simply contain the offset of the next block.
  82  * Those with larger size contain their size in the first SLOB_UNIT of
  83  * memory, and the offset of the next free block in the second SLOB_UNIT.
  84  */
  85 #if PAGE_SIZE <= (32767 * 2)
  86 typedef s16 slobidx_t;
  87 #else
  88 typedef s32 slobidx_t;
  89 #endif
  90 
  91 struct slob_block {
  92         slobidx_t units;
  93 };
  94 typedef struct slob_block slob_t;
  95 
  96 /*
  97  * All partially free slob pages go on these lists.
  98  */
  99 #define SLOB_BREAK1 256
 100 #define SLOB_BREAK2 1024
 101 static LIST_HEAD(free_slob_small);
 102 static LIST_HEAD(free_slob_medium);
 103 static LIST_HEAD(free_slob_large);
 104 
 105 /*
 106  * slob_page_free: true for pages on free_slob_pages list.
 107  */
 108 static inline int slob_page_free(struct page *sp)
 109 {
 110         return PageSlobFree(sp);
 111 }
 112 
 113 static void set_slob_page_free(struct page *sp, struct list_head *list)
 114 {
 115         list_add(&sp->slab_list, list);
 116         __SetPageSlobFree(sp);
 117 }
 118 
 119 static inline void clear_slob_page_free(struct page *sp)
 120 {
 121         list_del(&sp->slab_list);
 122         __ClearPageSlobFree(sp);
 123 }
 124 
 125 #define SLOB_UNIT sizeof(slob_t)
 126 #define SLOB_UNITS(size) DIV_ROUND_UP(size, SLOB_UNIT)
 127 
 128 /*
 129  * struct slob_rcu is inserted at the tail of allocated slob blocks, which
 130  * were created with a SLAB_TYPESAFE_BY_RCU slab. slob_rcu is used to free
 131  * the block using call_rcu.
 132  */
 133 struct slob_rcu {
 134         struct rcu_head head;
 135         int size;
 136 };
 137 
 138 /*
 139  * slob_lock protects all slob allocator structures.
 140  */
 141 static DEFINE_SPINLOCK(slob_lock);
 142 
 143 /*
 144  * Encode the given size and next info into a free slob block s.
 145  */
 146 static void set_slob(slob_t *s, slobidx_t size, slob_t *next)
 147 {
 148         slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
 149         slobidx_t offset = next - base;
 150 
 151         if (size > 1) {
 152                 s[0].units = size;
 153                 s[1].units = offset;
 154         } else
 155                 s[0].units = -offset;
 156 }
 157 
 158 /*
 159  * Return the size of a slob block.
 160  */
 161 static slobidx_t slob_units(slob_t *s)
 162 {
 163         if (s->units > 0)
 164                 return s->units;
 165         return 1;
 166 }
 167 
 168 /*
 169  * Return the next free slob block pointer after this one.
 170  */
 171 static slob_t *slob_next(slob_t *s)
 172 {
 173         slob_t *base = (slob_t *)((unsigned long)s & PAGE_MASK);
 174         slobidx_t next;
 175 
 176         if (s[0].units < 0)
 177                 next = -s[0].units;
 178         else
 179                 next = s[1].units;
 180         return base+next;
 181 }
 182 
 183 /*
 184  * Returns true if s is the last free block in its page.
 185  */
 186 static int slob_last(slob_t *s)
 187 {
 188         return !((unsigned long)slob_next(s) & ~PAGE_MASK);
 189 }
 190 
 191 static void *slob_new_pages(gfp_t gfp, int order, int node)
 192 {
 193         struct page *page;
 194 
 195 #ifdef CONFIG_NUMA
 196         if (node != NUMA_NO_NODE)
 197                 page = __alloc_pages_node(node, gfp, order);
 198         else
 199 #endif
 200                 page = alloc_pages(gfp, order);
 201 
 202         if (!page)
 203                 return NULL;
 204 
 205         mod_node_page_state(page_pgdat(page), NR_SLAB_UNRECLAIMABLE,
 206                             1 << order);
 207         return page_address(page);
 208 }
 209 
 210 static void slob_free_pages(void *b, int order)
 211 {
 212         struct page *sp = virt_to_page(b);
 213 
 214         if (current->reclaim_state)
 215                 current->reclaim_state->reclaimed_slab += 1 << order;
 216 
 217         mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE,
 218                             -(1 << order));
 219         __free_pages(sp, order);
 220 }
 221 
 222 /*
 223  * slob_page_alloc() - Allocate a slob block within a given slob_page sp.
 224  * @sp: Page to look in.
 225  * @size: Size of the allocation.
 226  * @align: Allocation alignment.
 227  * @align_offset: Offset in the allocated block that will be aligned.
 228  * @page_removed_from_list: Return parameter.
 229  *
 230  * Tries to find a chunk of memory at least @size bytes big within @page.
 231  *
 232  * Return: Pointer to memory if allocated, %NULL otherwise.  If the
 233  *         allocation fills up @page then the page is removed from the
 234  *         freelist, in this case @page_removed_from_list will be set to
 235  *         true (set to false otherwise).
 236  */
 237 static void *slob_page_alloc(struct page *sp, size_t size, int align,
 238                               int align_offset, bool *page_removed_from_list)
 239 {
 240         slob_t *prev, *cur, *aligned = NULL;
 241         int delta = 0, units = SLOB_UNITS(size);
 242 
 243         *page_removed_from_list = false;
 244         for (prev = NULL, cur = sp->freelist; ; prev = cur, cur = slob_next(cur)) {
 245                 slobidx_t avail = slob_units(cur);
 246 
 247                 /*
 248                  * 'aligned' will hold the address of the slob block so that the
 249                  * address 'aligned'+'align_offset' is aligned according to the
 250                  * 'align' parameter. This is for kmalloc() which prepends the
 251                  * allocated block with its size, so that the block itself is
 252                  * aligned when needed.
 253                  */
 254                 if (align) {
 255                         aligned = (slob_t *)
 256                                 (ALIGN((unsigned long)cur + align_offset, align)
 257                                  - align_offset);
 258                         delta = aligned - cur;
 259                 }
 260                 if (avail >= units + delta) { /* room enough? */
 261                         slob_t *next;
 262 
 263                         if (delta) { /* need to fragment head to align? */
 264                                 next = slob_next(cur);
 265                                 set_slob(aligned, avail - delta, next);
 266                                 set_slob(cur, delta, aligned);
 267                                 prev = cur;
 268                                 cur = aligned;
 269                                 avail = slob_units(cur);
 270                         }
 271 
 272                         next = slob_next(cur);
 273                         if (avail == units) { /* exact fit? unlink. */
 274                                 if (prev)
 275                                         set_slob(prev, slob_units(prev), next);
 276                                 else
 277                                         sp->freelist = next;
 278                         } else { /* fragment */
 279                                 if (prev)
 280                                         set_slob(prev, slob_units(prev), cur + units);
 281                                 else
 282                                         sp->freelist = cur + units;
 283                                 set_slob(cur + units, avail - units, next);
 284                         }
 285 
 286                         sp->units -= units;
 287                         if (!sp->units) {
 288                                 clear_slob_page_free(sp);
 289                                 *page_removed_from_list = true;
 290                         }
 291                         return cur;
 292                 }
 293                 if (slob_last(cur))
 294                         return NULL;
 295         }
 296 }
 297 
 298 /*
 299  * slob_alloc: entry point into the slob allocator.
 300  */
 301 static void *slob_alloc(size_t size, gfp_t gfp, int align, int node,
 302                                                         int align_offset)
 303 {
 304         struct page *sp;
 305         struct list_head *slob_list;
 306         slob_t *b = NULL;
 307         unsigned long flags;
 308         bool _unused;
 309 
 310         if (size < SLOB_BREAK1)
 311                 slob_list = &free_slob_small;
 312         else if (size < SLOB_BREAK2)
 313                 slob_list = &free_slob_medium;
 314         else
 315                 slob_list = &free_slob_large;
 316 
 317         spin_lock_irqsave(&slob_lock, flags);
 318         /* Iterate through each partially free page, try to find room */
 319         list_for_each_entry(sp, slob_list, slab_list) {
 320                 bool page_removed_from_list = false;
 321 #ifdef CONFIG_NUMA
 322                 /*
 323                  * If there's a node specification, search for a partial
 324                  * page with a matching node id in the freelist.
 325                  */
 326                 if (node != NUMA_NO_NODE && page_to_nid(sp) != node)
 327                         continue;
 328 #endif
 329                 /* Enough room on this page? */
 330                 if (sp->units < SLOB_UNITS(size))
 331                         continue;
 332 
 333                 b = slob_page_alloc(sp, size, align, align_offset, &page_removed_from_list);
 334                 if (!b)
 335                         continue;
 336 
 337                 /*
 338                  * If slob_page_alloc() removed sp from the list then we
 339                  * cannot call list functions on sp.  If so allocation
 340                  * did not fragment the page anyway so optimisation is
 341                  * unnecessary.
 342                  */
 343                 if (!page_removed_from_list) {
 344                         /*
 345                          * Improve fragment distribution and reduce our average
 346                          * search time by starting our next search here. (see
 347                          * Knuth vol 1, sec 2.5, pg 449)
 348                          */
 349                         if (!list_is_first(&sp->slab_list, slob_list))
 350                                 list_rotate_to_front(&sp->slab_list, slob_list);
 351                 }
 352                 break;
 353         }
 354         spin_unlock_irqrestore(&slob_lock, flags);
 355 
 356         /* Not enough space: must allocate a new page */
 357         if (!b) {
 358                 b = slob_new_pages(gfp & ~__GFP_ZERO, 0, node);
 359                 if (!b)
 360                         return NULL;
 361                 sp = virt_to_page(b);
 362                 __SetPageSlab(sp);
 363 
 364                 spin_lock_irqsave(&slob_lock, flags);
 365                 sp->units = SLOB_UNITS(PAGE_SIZE);
 366                 sp->freelist = b;
 367                 INIT_LIST_HEAD(&sp->slab_list);
 368                 set_slob(b, SLOB_UNITS(PAGE_SIZE), b + SLOB_UNITS(PAGE_SIZE));
 369                 set_slob_page_free(sp, slob_list);
 370                 b = slob_page_alloc(sp, size, align, align_offset, &_unused);
 371                 BUG_ON(!b);
 372                 spin_unlock_irqrestore(&slob_lock, flags);
 373         }
 374         if (unlikely(gfp & __GFP_ZERO))
 375                 memset(b, 0, size);
 376         return b;
 377 }
 378 
 379 /*
 380  * slob_free: entry point into the slob allocator.
 381  */
 382 static void slob_free(void *block, int size)
 383 {
 384         struct page *sp;
 385         slob_t *prev, *next, *b = (slob_t *)block;
 386         slobidx_t units;
 387         unsigned long flags;
 388         struct list_head *slob_list;
 389 
 390         if (unlikely(ZERO_OR_NULL_PTR(block)))
 391                 return;
 392         BUG_ON(!size);
 393 
 394         sp = virt_to_page(block);
 395         units = SLOB_UNITS(size);
 396 
 397         spin_lock_irqsave(&slob_lock, flags);
 398 
 399         if (sp->units + units == SLOB_UNITS(PAGE_SIZE)) {
 400                 /* Go directly to page allocator. Do not pass slob allocator */
 401                 if (slob_page_free(sp))
 402                         clear_slob_page_free(sp);
 403                 spin_unlock_irqrestore(&slob_lock, flags);
 404                 __ClearPageSlab(sp);
 405                 page_mapcount_reset(sp);
 406                 slob_free_pages(b, 0);
 407                 return;
 408         }
 409 
 410         if (!slob_page_free(sp)) {
 411                 /* This slob page is about to become partially free. Easy! */
 412                 sp->units = units;
 413                 sp->freelist = b;
 414                 set_slob(b, units,
 415                         (void *)((unsigned long)(b +
 416                                         SLOB_UNITS(PAGE_SIZE)) & PAGE_MASK));
 417                 if (size < SLOB_BREAK1)
 418                         slob_list = &free_slob_small;
 419                 else if (size < SLOB_BREAK2)
 420                         slob_list = &free_slob_medium;
 421                 else
 422                         slob_list = &free_slob_large;
 423                 set_slob_page_free(sp, slob_list);
 424                 goto out;
 425         }
 426 
 427         /*
 428          * Otherwise the page is already partially free, so find reinsertion
 429          * point.
 430          */
 431         sp->units += units;
 432 
 433         if (b < (slob_t *)sp->freelist) {
 434                 if (b + units == sp->freelist) {
 435                         units += slob_units(sp->freelist);
 436                         sp->freelist = slob_next(sp->freelist);
 437                 }
 438                 set_slob(b, units, sp->freelist);
 439                 sp->freelist = b;
 440         } else {
 441                 prev = sp->freelist;
 442                 next = slob_next(prev);
 443                 while (b > next) {
 444                         prev = next;
 445                         next = slob_next(prev);
 446                 }
 447 
 448                 if (!slob_last(prev) && b + units == next) {
 449                         units += slob_units(next);
 450                         set_slob(b, units, slob_next(next));
 451                 } else
 452                         set_slob(b, units, next);
 453 
 454                 if (prev + slob_units(prev) == b) {
 455                         units = slob_units(b) + slob_units(prev);
 456                         set_slob(prev, units, slob_next(b));
 457                 } else
 458                         set_slob(prev, slob_units(prev), b);
 459         }
 460 out:
 461         spin_unlock_irqrestore(&slob_lock, flags);
 462 }
 463 
 464 /*
 465  * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend.
 466  */
 467 
 468 static __always_inline void *
 469 __do_kmalloc_node(size_t size, gfp_t gfp, int node, unsigned long caller)
 470 {
 471         unsigned int *m;
 472         int minalign = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
 473         void *ret;
 474 
 475         gfp &= gfp_allowed_mask;
 476 
 477         fs_reclaim_acquire(gfp);
 478         fs_reclaim_release(gfp);
 479 
 480         if (size < PAGE_SIZE - minalign) {
 481                 int align = minalign;
 482 
 483                 /*
 484                  * For power of two sizes, guarantee natural alignment for
 485                  * kmalloc()'d objects.
 486                  */
 487                 if (is_power_of_2(size))
 488                         align = max(minalign, (int) size);
 489 
 490                 if (!size)
 491                         return ZERO_SIZE_PTR;
 492 
 493                 m = slob_alloc(size + minalign, gfp, align, node, minalign);
 494 
 495                 if (!m)
 496                         return NULL;
 497                 *m = size;
 498                 ret = (void *)m + minalign;
 499 
 500                 trace_kmalloc_node(caller, ret,
 501                                    size, size + minalign, gfp, node);
 502         } else {
 503                 unsigned int order = get_order(size);
 504 
 505                 if (likely(order))
 506                         gfp |= __GFP_COMP;
 507                 ret = slob_new_pages(gfp, order, node);
 508 
 509                 trace_kmalloc_node(caller, ret,
 510                                    size, PAGE_SIZE << order, gfp, node);
 511         }
 512 
 513         kmemleak_alloc(ret, size, 1, gfp);
 514         return ret;
 515 }
 516 
 517 void *__kmalloc(size_t size, gfp_t gfp)
 518 {
 519         return __do_kmalloc_node(size, gfp, NUMA_NO_NODE, _RET_IP_);
 520 }
 521 EXPORT_SYMBOL(__kmalloc);
 522 
 523 void *__kmalloc_track_caller(size_t size, gfp_t gfp, unsigned long caller)
 524 {
 525         return __do_kmalloc_node(size, gfp, NUMA_NO_NODE, caller);
 526 }
 527 
 528 #ifdef CONFIG_NUMA
 529 void *__kmalloc_node_track_caller(size_t size, gfp_t gfp,
 530                                         int node, unsigned long caller)
 531 {
 532         return __do_kmalloc_node(size, gfp, node, caller);
 533 }
 534 #endif
 535 
 536 void kfree(const void *block)
 537 {
 538         struct page *sp;
 539 
 540         trace_kfree(_RET_IP_, block);
 541 
 542         if (unlikely(ZERO_OR_NULL_PTR(block)))
 543                 return;
 544         kmemleak_free(block);
 545 
 546         sp = virt_to_page(block);
 547         if (PageSlab(sp)) {
 548                 int align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
 549                 unsigned int *m = (unsigned int *)(block - align);
 550                 slob_free(m, *m + align);
 551         } else {
 552                 unsigned int order = compound_order(sp);
 553                 mod_node_page_state(page_pgdat(sp), NR_SLAB_UNRECLAIMABLE,
 554                                     -(1 << order));
 555                 __free_pages(sp, order);
 556 
 557         }
 558 }
 559 EXPORT_SYMBOL(kfree);
 560 
 561 /* can't use ksize for kmem_cache_alloc memory, only kmalloc */
 562 size_t __ksize(const void *block)
 563 {
 564         struct page *sp;
 565         int align;
 566         unsigned int *m;
 567 
 568         BUG_ON(!block);
 569         if (unlikely(block == ZERO_SIZE_PTR))
 570                 return 0;
 571 
 572         sp = virt_to_page(block);
 573         if (unlikely(!PageSlab(sp)))
 574                 return page_size(sp);
 575 
 576         align = max_t(size_t, ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
 577         m = (unsigned int *)(block - align);
 578         return SLOB_UNITS(*m) * SLOB_UNIT;
 579 }
 580 EXPORT_SYMBOL(__ksize);
 581 
 582 int __kmem_cache_create(struct kmem_cache *c, slab_flags_t flags)
 583 {
 584         if (flags & SLAB_TYPESAFE_BY_RCU) {
 585                 /* leave room for rcu footer at the end of object */
 586                 c->size += sizeof(struct slob_rcu);
 587         }
 588         c->flags = flags;
 589         return 0;
 590 }
 591 
 592 static void *slob_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
 593 {
 594         void *b;
 595 
 596         flags &= gfp_allowed_mask;
 597 
 598         fs_reclaim_acquire(flags);
 599         fs_reclaim_release(flags);
 600 
 601         if (c->size < PAGE_SIZE) {
 602                 b = slob_alloc(c->size, flags, c->align, node, 0);
 603                 trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size,
 604                                             SLOB_UNITS(c->size) * SLOB_UNIT,
 605                                             flags, node);
 606         } else {
 607                 b = slob_new_pages(flags, get_order(c->size), node);
 608                 trace_kmem_cache_alloc_node(_RET_IP_, b, c->object_size,
 609                                             PAGE_SIZE << get_order(c->size),
 610                                             flags, node);
 611         }
 612 
 613         if (b && c->ctor) {
 614                 WARN_ON_ONCE(flags & __GFP_ZERO);
 615                 c->ctor(b);
 616         }
 617 
 618         kmemleak_alloc_recursive(b, c->size, 1, c->flags, flags);
 619         return b;
 620 }
 621 
 622 void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
 623 {
 624         return slob_alloc_node(cachep, flags, NUMA_NO_NODE);
 625 }
 626 EXPORT_SYMBOL(kmem_cache_alloc);
 627 
 628 #ifdef CONFIG_NUMA
 629 void *__kmalloc_node(size_t size, gfp_t gfp, int node)
 630 {
 631         return __do_kmalloc_node(size, gfp, node, _RET_IP_);
 632 }
 633 EXPORT_SYMBOL(__kmalloc_node);
 634 
 635 void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t gfp, int node)
 636 {
 637         return slob_alloc_node(cachep, gfp, node);
 638 }
 639 EXPORT_SYMBOL(kmem_cache_alloc_node);
 640 #endif
 641 
 642 static void __kmem_cache_free(void *b, int size)
 643 {
 644         if (size < PAGE_SIZE)
 645                 slob_free(b, size);
 646         else
 647                 slob_free_pages(b, get_order(size));
 648 }
 649 
 650 static void kmem_rcu_free(struct rcu_head *head)
 651 {
 652         struct slob_rcu *slob_rcu = (struct slob_rcu *)head;
 653         void *b = (void *)slob_rcu - (slob_rcu->size - sizeof(struct slob_rcu));
 654 
 655         __kmem_cache_free(b, slob_rcu->size);
 656 }
 657 
 658 void kmem_cache_free(struct kmem_cache *c, void *b)
 659 {
 660         kmemleak_free_recursive(b, c->flags);
 661         if (unlikely(c->flags & SLAB_TYPESAFE_BY_RCU)) {
 662                 struct slob_rcu *slob_rcu;
 663                 slob_rcu = b + (c->size - sizeof(struct slob_rcu));
 664                 slob_rcu->size = c->size;
 665                 call_rcu(&slob_rcu->head, kmem_rcu_free);
 666         } else {
 667                 __kmem_cache_free(b, c->size);
 668         }
 669 
 670         trace_kmem_cache_free(_RET_IP_, b);
 671 }
 672 EXPORT_SYMBOL(kmem_cache_free);
 673 
 674 void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
 675 {
 676         __kmem_cache_free_bulk(s, size, p);
 677 }
 678 EXPORT_SYMBOL(kmem_cache_free_bulk);
 679 
 680 int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
 681                                                                 void **p)
 682 {
 683         return __kmem_cache_alloc_bulk(s, flags, size, p);
 684 }
 685 EXPORT_SYMBOL(kmem_cache_alloc_bulk);
 686 
 687 int __kmem_cache_shutdown(struct kmem_cache *c)
 688 {
 689         /* No way to check for remaining objects */
 690         return 0;
 691 }
 692 
 693 void __kmem_cache_release(struct kmem_cache *c)
 694 {
 695 }
 696 
 697 int __kmem_cache_shrink(struct kmem_cache *d)
 698 {
 699         return 0;
 700 }
 701 
 702 struct kmem_cache kmem_cache_boot = {
 703         .name = "kmem_cache",
 704         .size = sizeof(struct kmem_cache),
 705         .flags = SLAB_PANIC,
 706         .align = ARCH_KMALLOC_MINALIGN,
 707 };
 708 
 709 void __init kmem_cache_init(void)
 710 {
 711         kmem_cache = &kmem_cache_boot;
 712         slab_state = UP;
 713 }
 714 
 715 void __init kmem_cache_init_late(void)
 716 {
 717         slab_state = FULL;
 718 }