1/*
   2 * SLUB: A slab allocator that limits cache line use instead of queuing
   3 * objects in per cpu and per node lists.
   4 *
   5 * The allocator synchronizes using per slab locks or atomic operatios
   6 * and only uses a centralized lock to manage a pool of partial slabs.
   7 *
   8 * (C) 2007 SGI, Christoph Lameter
   9 * (C) 2011 Linux Foundation, Christoph Lameter
  10 */
  11
  12#include <linux/mm.h>
  13#include <linux/swap.h> /* struct reclaim_state */
  14#include <linux/module.h>
  15#include <linux/bit_spinlock.h>
  16#include <linux/interrupt.h>
 
  17#include <linux/bitops.h>
  18#include <linux/slab.h>
 
  19#include <linux/proc_fs.h>
  20#include <linux/seq_file.h>
  21#include <linux/kmemcheck.h>
 
  22#include <linux/cpu.h>
  23#include <linux/cpuset.h>
  24#include <linux/mempolicy.h>
  25#include <linux/ctype.h>
 
  26#include <linux/debugobjects.h>
  27#include <linux/kallsyms.h>
 
  28#include <linux/memory.h>
  29#include <linux/math64.h>
  30#include <linux/fault-inject.h>
 
  31#include <linux/stacktrace.h>
  32#include <linux/prefetch.h>
 
 
 
 
 
  33
 
  34#include <trace/events/kmem.h>
  35
 
 
  36/*
  37 * Lock order:
  38 *   1. slub_lock (Global Semaphore)
  39 *   2. node->list_lock
  40 *   3. slab_lock(page) (Only on some arches and for debugging)
 
 
  41 *
  42 *   slub_lock
  43 *
  44 *   The role of the slub_lock is to protect the list of all the slabs
  45 *   and to synchronize major metadata changes to slab cache structures.
 
 
 
 
 
 
  46 *
  47 *   The slab_lock is only used for debugging and on arches that do not
  48 *   have the ability to do a cmpxchg_double. It only protects the second
  49 *   double word in the page struct. Meaning
  50 *	A. page->freelist	-> List of object free in a page
  51 *	B. page->counters	-> Counters of objects
  52 *	C. page->frozen		-> frozen state
  53 *
  54 *   If a slab is frozen then it is exempt from list management. It is not
  55 *   on any list. The processor that froze the slab is the one who can
  56 *   perform list operations on the page. Other processors may put objects
  57 *   onto the freelist but the processor that froze the slab is the only
  58 *   one that can retrieve the objects from the page's freelist.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  59 *
  60 *   The list_lock protects the partial and full list on each node and
  61 *   the partial slab counter. If taken then no new slabs may be added or
  62 *   removed from the lists nor make the number of partial slabs be modified.
  63 *   (Note that the total number of slabs is an atomic value that may be
  64 *   modified without taking the list lock).
  65 *
  66 *   The list_lock is a centralized lock and thus we avoid taking it as
  67 *   much as possible. As long as SLUB does not have to handle partial
  68 *   slabs, operations can continue without any centralized lock. F.e.
  69 *   allocating a long series of objects that fill up slabs does not require
  70 *   the list lock.
  71 *   Interrupts are disabled during allocation and deallocation in order to
  72 *   make the slab allocator safe to use in the context of an irq. In addition
  73 *   interrupts are disabled to ensure that the processor does not change
  74 *   while handling per_cpu slabs, due to kernel preemption.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
  75 *
  76 * SLUB assigns one slab for allocation to each processor.
  77 * Allocations only occur from these slabs called cpu slabs.
  78 *
  79 * Slabs with free elements are kept on a partial list and during regular
  80 * operations no list for full slabs is used. If an object in a full slab is
  81 * freed then the slab will show up again on the partial lists.
  82 * We track full slabs for debugging purposes though because otherwise we
  83 * cannot scan all objects.
  84 *
  85 * Slabs are freed when they become empty. Teardown and setup is
  86 * minimal so we rely on the page allocators per cpu caches for
  87 * fast frees and allocs.
  88 *
  89 * Overloading of page flags that are otherwise used for LRU management.
  90 *
  91 * PageActive 		The slab is frozen and exempt from list processing.
  92 * 			This means that the slab is dedicated to a purpose
  93 * 			such as satisfying allocations for a specific
  94 * 			processor. Objects may be freed in the slab while
  95 * 			it is frozen but slab_free will then skip the usual
  96 * 			list operations. It is up to the processor holding
  97 * 			the slab to integrate the slab into the slab lists
  98 * 			when the slab is no longer needed.
  99 *
 100 * 			One use of this flag is to mark slabs that are
 101 * 			used for allocations. Then such a slab becomes a cpu
 102 * 			slab. The cpu slab may be equipped with an additional
 103 * 			freelist that allows lockless access to
 104 * 			free objects in addition to the regular freelist
 105 * 			that requires the slab lock.
 106 *
 107 * PageError		Slab requires special handling due to debug
 108 * 			options set. This moves	slab handling out of
 109 * 			the fast path and disables lockless freelists.
 110 */
 111
 112#define SLAB_DEBUG_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 113		SLAB_TRACE | SLAB_DEBUG_FREE)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 114
 115static inline int kmem_cache_debug(struct kmem_cache *s)
 116{
 117#ifdef CONFIG_SLUB_DEBUG
 118	return unlikely(s->flags & SLAB_DEBUG_FLAGS);
 
 119#else
 120	return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 121#endif
 122}
 123
 124/*
 125 * Issues still to be resolved:
 126 *
 127 * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
 128 *
 129 * - Variable sizing of the per node arrays
 130 */
 131
 132/* Enable to test recovery from slab corruption on boot */
 133#undef SLUB_RESILIENCY_TEST
 134
 135/* Enable to log cmpxchg failures */
 136#undef SLUB_DEBUG_CMPXCHG
 137
 
 138/*
 139 * Mininum number of partial slabs. These will be left on the partial
 140 * lists even if they are empty. kmem_cache_shrink may reclaim them.
 141 */
 142#define MIN_PARTIAL 5
 143
 144/*
 145 * Maximum number of desirable partial slabs.
 146 * The existence of more partial slabs makes kmem_cache_shrink
 147 * sort the partial list by the number of objects in the.
 148 */
 149#define MAX_PARTIAL 10
 
 
 
 
 150
 151#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
 152				SLAB_POISON | SLAB_STORE_USER)
 153
 154/*
 155 * Debugging flags that require metadata to be stored in the slab.  These get
 156 * disabled when slub_debug=O is used and a cache's min order increases with
 157 * metadata.
 158 */
 159#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
 
 
 160
 161/*
 162 * Set of flags that will prevent slab merging
 
 
 163 */
 164#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
 165		SLAB_TRACE | SLAB_DESTROY_BY_RCU | SLAB_NOLEAKTRACE | \
 166		SLAB_FAILSLAB)
 167
 168#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_RECLAIM_ACCOUNT | \
 169		SLAB_CACHE_DMA | SLAB_NOTRACK)
 170
 171#define OO_SHIFT	16
 172#define OO_MASK		((1 << OO_SHIFT) - 1)
 173#define MAX_OBJS_PER_PAGE	32767 /* since page.objects is u15 */
 174
 175/* Internal SLUB flags */
 176#define __OBJECT_POISON		0x80000000UL /* Poison object */
 177#define __CMPXCHG_DOUBLE	0x40000000UL /* Use cmpxchg_double */
 
 178
 179static int kmem_size = sizeof(struct kmem_cache);
 180
 181#ifdef CONFIG_SMP
 182static struct notifier_block slab_notifier;
 183#endif
 184
 185static enum {
 186	DOWN,		/* No slab functionality available */
 187	PARTIAL,	/* Kmem_cache_node works */
 188	UP,		/* Everything works but does not show up in sysfs */
 189	SYSFS		/* Sysfs up */
 190} slab_state = DOWN;
 191
 192/* A list of all slab caches on the system */
 193static DECLARE_RWSEM(slub_lock);
 194static LIST_HEAD(slab_caches);
 195
 196/*
 197 * Tracking user of a slab.
 198 */
 199#define TRACK_ADDRS_COUNT 16
 200struct track {
 201	unsigned long addr;	/* Called from address */
 202#ifdef CONFIG_STACKTRACE
 203	unsigned long addrs[TRACK_ADDRS_COUNT];	/* Called from address */
 204#endif
 205	int cpu;		/* Was running on cpu */
 206	int pid;		/* Pid context */
 207	unsigned long when;	/* When did the operation occur */
 208};
 209
 210enum track_item { TRACK_ALLOC, TRACK_FREE };
 211
 212#ifdef CONFIG_SYSFS
 213static int sysfs_slab_add(struct kmem_cache *);
 214static int sysfs_slab_alias(struct kmem_cache *, const char *);
 215static void sysfs_slab_remove(struct kmem_cache *);
 216
 217#else
 218static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
 219static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
 220							{ return 0; }
 221static inline void sysfs_slab_remove(struct kmem_cache *s)
 222{
 223	kfree(s->name);
 224	kfree(s);
 225}
 226
 
 
 
 
 227#endif
 228
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 229static inline void stat(const struct kmem_cache *s, enum stat_item si)
 230{
 231#ifdef CONFIG_SLUB_STATS
 232	__this_cpu_inc(s->cpu_slab->stat[si]);
 
 
 
 
 233#endif
 234}
 235
 236/********************************************************************
 237 * 			Core slab cache functions
 238 *******************************************************************/
 239
 240int slab_is_available(void)
 241{
 242	return slab_state >= UP;
 
 
 243}
 244
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 245static inline struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
 246{
 247	return s->node[node];
 248}
 249
 250/* Verify that a pointer has an address that is valid within a slab page */
 251static inline int check_valid_pointer(struct kmem_cache *s,
 252				struct page *page, const void *object)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 253{
 254	void *base;
 255
 256	if (!object)
 257		return 1;
 
 
 
 
 
 258
 259	base = page_address(page);
 260	if (object < base || object >= base + page->objects * s->size ||
 261		(object - base) % s->size) {
 262		return 0;
 263	}
 264
 265	return 1;
 
 
 
 
 
 266}
 267
 268static inline void *get_freepointer(struct kmem_cache *s, void *object)
 269{
 270	return *(void **)(object + s->offset);
 
 
 
 
 
 
 271}
 272
 
 273static void prefetch_freepointer(const struct kmem_cache *s, void *object)
 274{
 275	prefetch(object + s->offset);
 276}
 
 277
 
 
 
 
 
 
 
 
 
 
 
 278static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
 279{
 280	void *p;
 
 281
 282#ifdef CONFIG_DEBUG_PAGEALLOC
 283	probe_kernel_read(&p, (void **)(object + s->offset), sizeof(p));
 284#else
 285	p = get_freepointer(s, object);
 286#endif
 287	return p;
 
 288}
 289
 290static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
 291{
 292	*(void **)(object + s->offset) = fp;
 293}
 294
 295/* Loop over all objects in a slab */
 296#define for_each_object(__p, __s, __addr, __objects) \
 297	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
 298			__p += (__s)->size)
 299
 300/* Determine object index from a given position */
 301static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
 302{
 303	return (p - addr) / s->size;
 304}
 305
 306static inline size_t slab_ksize(const struct kmem_cache *s)
 
 
 
 307{
 308#ifdef CONFIG_SLUB_DEBUG
 309	/*
 310	 * Debugging requires use of the padding between object
 311	 * and whatever may come after it.
 312	 */
 313	if (s->flags & (SLAB_RED_ZONE | SLAB_POISON))
 314		return s->objsize;
 315
 316#endif
 317	/*
 318	 * If we have the need to store the freelist pointer
 319	 * back there or track user information then we can
 320	 * only use the space before that information.
 321	 */
 322	if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
 
 
 323		return s->inuse;
 324	/*
 325	 * Else we can use all the padding etc for the allocation
 326	 */
 327	return s->size;
 328}
 329
 330static inline int order_objects(int order, unsigned long size, int reserved)
 
 
 
 
 
 
 331{
 332	return ((PAGE_SIZE << order) - reserved) / size;
 333}
 334
 335static inline struct kmem_cache_order_objects oo_make(int order,
 336		unsigned long size, int reserved)
 337{
 338	struct kmem_cache_order_objects x = {
 339		(order << OO_SHIFT) + order_objects(order, size, reserved)
 340	};
 341
 342	return x;
 343}
 344
 345static inline int oo_order(struct kmem_cache_order_objects x)
 346{
 347	return x.x >> OO_SHIFT;
 348}
 349
 350static inline int oo_objects(struct kmem_cache_order_objects x)
 351{
 352	return x.x & OO_MASK;
 353}
 354
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 355/*
 356 * Per slab locking using the pagelock
 357 */
 358static __always_inline void slab_lock(struct page *page)
 
 
 
 
 
 
 
 
 
 
 
 
 
 359{
 360	bit_spin_lock(PG_locked, &page->flags);
 
 
 
 
 
 
 
 361}
 362
 363static __always_inline void slab_unlock(struct page *page)
 
 
 
 364{
 365	__bit_spin_unlock(PG_locked, &page->flags);
 
 
 
 
 
 
 
 
 
 
 
 366}
 367
 368/* Interrupts must be disabled (for the fallback code to work right) */
 369static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 
 
 
 
 
 
 370		void *freelist_old, unsigned long counters_old,
 371		void *freelist_new, unsigned long counters_new,
 372		const char *n)
 373{
 374	VM_BUG_ON(!irqs_disabled());
 375#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
 376    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 
 
 377	if (s->flags & __CMPXCHG_DOUBLE) {
 378		if (cmpxchg_double(&page->freelist, &page->counters,
 379			freelist_old, counters_old,
 380			freelist_new, counters_new))
 381		return 1;
 382	} else
 383#endif
 384	{
 385		slab_lock(page);
 386		if (page->freelist == freelist_old && page->counters == counters_old) {
 387			page->freelist = freelist_new;
 388			page->counters = counters_new;
 389			slab_unlock(page);
 390			return 1;
 391		}
 392		slab_unlock(page);
 393	}
 
 
 394
 395	cpu_relax();
 396	stat(s, CMPXCHG_DOUBLE_FAIL);
 397
 398#ifdef SLUB_DEBUG_CMPXCHG
 399	printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
 400#endif
 401
 402	return 0;
 403}
 404
 405static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct page *page,
 406		void *freelist_old, unsigned long counters_old,
 407		void *freelist_new, unsigned long counters_new,
 408		const char *n)
 409{
 410#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
 411    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
 412	if (s->flags & __CMPXCHG_DOUBLE) {
 413		if (cmpxchg_double(&page->freelist, &page->counters,
 414			freelist_old, counters_old,
 415			freelist_new, counters_new))
 416		return 1;
 417	} else
 418#endif
 419	{
 420		unsigned long flags;
 421
 422		local_irq_save(flags);
 423		slab_lock(page);
 424		if (page->freelist == freelist_old && page->counters == counters_old) {
 425			page->freelist = freelist_new;
 426			page->counters = counters_new;
 427			slab_unlock(page);
 428			local_irq_restore(flags);
 429			return 1;
 430		}
 431		slab_unlock(page);
 432		local_irq_restore(flags);
 433	}
 
 
 434
 435	cpu_relax();
 436	stat(s, CMPXCHG_DOUBLE_FAIL);
 437
 438#ifdef SLUB_DEBUG_CMPXCHG
 439	printk(KERN_INFO "%s %s: cmpxchg double redo ", n, s->name);
 440#endif
 441
 442	return 0;
 443}
 444
 445#ifdef CONFIG_SLUB_DEBUG
 446/*
 447 * Determine a map of object in use on a page.
 448 *
 449 * Node listlock must be held to guarantee that the page does
 450 * not vanish from under us.
 451 */
 452static void get_map(struct kmem_cache *s, struct page *page, unsigned long *map)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 453{
 
 454	void *p;
 455	void *addr = page_address(page);
 456
 457	for (p = page->freelist; p; p = get_freepointer(s, p))
 458		set_bit(slab_index(p, s, addr), map);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 459}
 460
 461/*
 462 * Debug settings:
 463 */
 464#ifdef CONFIG_SLUB_DEBUG_ON
 465static int slub_debug = DEBUG_DEFAULT_FLAGS;
 466#else
 467static int slub_debug;
 468#endif
 469
 470static char *slub_debug_slabs;
 471static int disable_higher_order_debug;
 472
 473/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 474 * Object debugging
 475 */
 476static void print_section(char *text, u8 *addr, unsigned int length)
 
 
 
 477{
 478	print_hex_dump(KERN_ERR, text, DUMP_PREFIX_ADDRESS, 16, 1, addr,
 479			length, 1);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 480}
 481
 482static struct track *get_track(struct kmem_cache *s, void *object,
 483	enum track_item alloc)
 484{
 485	struct track *p;
 486
 487	if (s->offset)
 488		p = object + s->offset + sizeof(void *);
 489	else
 490		p = object + s->inuse;
 
 
 
 
 
 
 
 
 
 
 491
 492	return p + alloc;
 
 
 
 
 
 493}
 
 494
 495static void set_track(struct kmem_cache *s, void *object,
 496			enum track_item alloc, unsigned long addr)
 
 497{
 498	struct track *p = get_track(s, object, alloc);
 499
 500	if (addr) {
 501#ifdef CONFIG_STACKTRACE
 502		struct stack_trace trace;
 503		int i;
 504
 505		trace.nr_entries = 0;
 506		trace.max_entries = TRACK_ADDRS_COUNT;
 507		trace.entries = p->addrs;
 508		trace.skip = 3;
 509		save_stack_trace(&trace);
 510
 511		/* See rant in lockdep.c */
 512		if (trace.nr_entries != 0 &&
 513		    trace.entries[trace.nr_entries - 1] == ULONG_MAX)
 514			trace.nr_entries--;
 515
 516		for (i = trace.nr_entries; i < TRACK_ADDRS_COUNT; i++)
 517			p->addrs[i] = 0;
 518#endif
 519		p->addr = addr;
 520		p->cpu = smp_processor_id();
 521		p->pid = current->pid;
 522		p->when = jiffies;
 523	} else
 524		memset(p, 0, sizeof(struct track));
 525}
 526
 527static void init_tracking(struct kmem_cache *s, void *object)
 528{
 
 
 529	if (!(s->flags & SLAB_STORE_USER))
 530		return;
 531
 532	set_track(s, object, TRACK_FREE, 0UL);
 533	set_track(s, object, TRACK_ALLOC, 0UL);
 534}
 535
 536static void print_track(const char *s, struct track *t)
 537{
 
 
 538	if (!t->addr)
 539		return;
 540
 541	printk(KERN_ERR "INFO: %s in %pS age=%lu cpu=%u pid=%d\n",
 542		s, (void *)t->addr, jiffies - t->when, t->cpu, t->pid);
 543#ifdef CONFIG_STACKTRACE
 544	{
 545		int i;
 546		for (i = 0; i < TRACK_ADDRS_COUNT; i++)
 547			if (t->addrs[i])
 548				printk(KERN_ERR "\t%pS\n", (void *)t->addrs[i]);
 549			else
 550				break;
 551	}
 552#endif
 553}
 554
 555static void print_tracking(struct kmem_cache *s, void *object)
 556{
 
 557	if (!(s->flags & SLAB_STORE_USER))
 558		return;
 559
 560	print_track("Allocated", get_track(s, object, TRACK_ALLOC));
 561	print_track("Freed", get_track(s, object, TRACK_FREE));
 562}
 563
 564static void print_page_info(struct page *page)
 565{
 566	printk(KERN_ERR "INFO: Slab 0x%p objects=%u used=%u fp=0x%p flags=0x%04lx\n",
 567		page, page->objects, page->inuse, page->freelist, page->flags);
 
 
 568
 
 
 
 569}
 570
 571static void slab_bug(struct kmem_cache *s, char *fmt, ...)
 572{
 
 573	va_list args;
 574	char buf[100];
 575
 576	va_start(args, fmt);
 577	vsnprintf(buf, sizeof(buf), fmt, args);
 
 
 
 
 578	va_end(args);
 579	printk(KERN_ERR "========================================"
 580			"=====================================\n");
 581	printk(KERN_ERR "BUG %s (%s): %s\n", s->name, print_tainted(), buf);
 582	printk(KERN_ERR "----------------------------------------"
 583			"-------------------------------------\n\n");
 584}
 585
 
 586static void slab_fix(struct kmem_cache *s, char *fmt, ...)
 587{
 
 588	va_list args;
 589	char buf[100];
 
 
 590
 591	va_start(args, fmt);
 592	vsnprintf(buf, sizeof(buf), fmt, args);
 
 
 593	va_end(args);
 594	printk(KERN_ERR "FIX %s: %s\n", s->name, buf);
 595}
 596
 597static void print_trailer(struct kmem_cache *s, struct page *page, u8 *p)
 598{
 599	unsigned int off;	/* Offset of last byte */
 600	u8 *addr = page_address(page);
 601
 602	print_tracking(s, p);
 603
 604	print_page_info(page);
 605
 606	printk(KERN_ERR "INFO: Object 0x%p @offset=%tu fp=0x%p\n\n",
 607			p, p - addr, get_freepointer(s, p));
 608
 609	if (p > addr + 16)
 610		print_section("Bytes b4 ", p - 16, 16);
 
 
 
 611
 612	print_section("Object ", p, min_t(unsigned long, s->objsize,
 613				PAGE_SIZE));
 614	if (s->flags & SLAB_RED_ZONE)
 615		print_section("Redzone ", p + s->objsize,
 616			s->inuse - s->objsize);
 617
 618	if (s->offset)
 619		off = s->offset + sizeof(void *);
 620	else
 621		off = s->inuse;
 622
 623	if (s->flags & SLAB_STORE_USER)
 624		off += 2 * sizeof(struct track);
 625
 626	if (off != s->size)
 
 
 
 
 
 627		/* Beginning of the filler is the free pointer */
 628		print_section("Padding ", p + off, s->size - off);
 
 629
 630	dump_stack();
 631}
 632
 633static void object_err(struct kmem_cache *s, struct page *page,
 634			u8 *object, char *reason)
 635{
 
 
 
 636	slab_bug(s, "%s", reason);
 637	print_trailer(s, page, object);
 
 638}
 639
 640static void slab_err(struct kmem_cache *s, struct page *page, char *fmt, ...)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 641{
 642	va_list args;
 643	char buf[100];
 644
 
 
 
 645	va_start(args, fmt);
 646	vsnprintf(buf, sizeof(buf), fmt, args);
 647	va_end(args);
 648	slab_bug(s, "%s", buf);
 649	print_page_info(page);
 650	dump_stack();
 
 651}
 652
 653static void init_object(struct kmem_cache *s, void *object, u8 val)
 654{
 655	u8 *p = object;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 656
 657	if (s->flags & __OBJECT_POISON) {
 658		memset(p, POISON_FREE, s->objsize - 1);
 659		p[s->objsize - 1] = POISON_END;
 660	}
 661
 662	if (s->flags & SLAB_RED_ZONE)
 663		memset(p + s->objsize, val, s->inuse - s->objsize);
 
 664}
 665
 666static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
 667						void *from, void *to)
 668{
 669	slab_fix(s, "Restoring 0x%p-0x%p=0x%x\n", from, to - 1, data);
 670	memset(from, data, to - from);
 671}
 672
 673static int check_bytes_and_report(struct kmem_cache *s, struct page *page,
 674			u8 *object, char *what,
 675			u8 *start, unsigned int value, unsigned int bytes)
 
 
 
 
 
 
 
 676{
 677	u8 *fault;
 678	u8 *end;
 
 679
 680	fault = memchr_inv(start, value, bytes);
 
 
 681	if (!fault)
 682		return 1;
 683
 684	end = start + bytes;
 685	while (end > fault && end[-1] == value)
 686		end--;
 687
 
 
 
 688	slab_bug(s, "%s overwritten", what);
 689	printk(KERN_ERR "INFO: 0x%p-0x%p. First byte 0x%x instead of 0x%x\n",
 690					fault, end - 1, fault[0], value);
 691	print_trailer(s, page, object);
 692
 
 693	restore_bytes(s, what, value, fault, end);
 694	return 0;
 695}
 696
 697/*
 698 * Object layout:
 699 *
 700 * object address
 701 * 	Bytes of the object to be managed.
 702 * 	If the freepointer may overlay the object then the free
 703 * 	pointer is the first word of the object.
 704 *
 705 * 	Poisoning uses 0x6b (POISON_FREE) and the last byte is
 706 * 	0xa5 (POISON_END)
 707 *
 708 * object + s->objsize
 709 * 	Padding to reach word boundary. This is also used for Redzoning.
 710 * 	Padding is extended by another word if Redzoning is enabled and
 711 * 	objsize == inuse.
 712 *
 713 * 	We fill with 0xbb (RED_INACTIVE) for inactive objects and with
 714 * 	0xcc (RED_ACTIVE) for objects in use.
 715 *
 716 * object + s->inuse
 717 * 	Meta data starts here.
 718 *
 719 * 	A. Free pointer (if we cannot overwrite object on free)
 720 * 	B. Tracking data for SLAB_STORE_USER
 721 * 	C. Padding to reach required alignment boundary or at mininum
 
 722 * 		one word if debugging is on to be able to detect writes
 723 * 		before the word boundary.
 724 *
 725 *	Padding is done using 0x5a (POISON_INUSE)
 726 *
 727 * object + s->size
 728 * 	Nothing is used beyond s->size.
 729 *
 730 * If slabcaches are merged then the objsize and inuse boundaries are mostly
 731 * ignored. And therefore no slab options that rely on these boundaries
 732 * may be used with merged slabcaches.
 733 */
 734
 735static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
 736{
 737	unsigned long off = s->inuse;	/* The end of info */
 738
 739	if (s->offset)
 740		/* Freepointer is placed after the object. */
 741		off += sizeof(void *);
 742
 743	if (s->flags & SLAB_STORE_USER)
 744		/* We also have user information there */
 745		off += 2 * sizeof(struct track);
 746
 747	if (s->size == off)
 
 
 
 
 
 
 748		return 1;
 749
 750	return check_bytes_and_report(s, page, p, "Object padding",
 751				p + off, POISON_INUSE, s->size - off);
 752}
 753
 754/* Check the pad bytes at the end of a slab page */
 755static int slab_pad_check(struct kmem_cache *s, struct page *page)
 
 756{
 757	u8 *start;
 758	u8 *fault;
 759	u8 *end;
 
 760	int length;
 761	int remainder;
 762
 763	if (!(s->flags & SLAB_POISON))
 764		return 1;
 765
 766	start = page_address(page);
 767	length = (PAGE_SIZE << compound_order(page)) - s->reserved;
 768	end = start + length;
 769	remainder = length % s->size;
 770	if (!remainder)
 771		return 1;
 772
 773	fault = memchr_inv(end - remainder, POISON_INUSE, remainder);
 
 
 
 774	if (!fault)
 775		return 1;
 776	while (end > fault && end[-1] == POISON_INUSE)
 777		end--;
 778
 779	slab_err(s, page, "Padding overwritten. 0x%p-0x%p", fault, end - 1);
 780	print_section("Padding ", end - remainder, remainder);
 
 781
 782	restore_bytes(s, "slab padding", POISON_INUSE, end - remainder, end);
 783	return 0;
 784}
 785
 786static int check_object(struct kmem_cache *s, struct page *page,
 787					void *object, u8 val)
 788{
 789	u8 *p = object;
 790	u8 *endobject = object + s->objsize;
 
 
 791
 792	if (s->flags & SLAB_RED_ZONE) {
 793		if (!check_bytes_and_report(s, page, object, "Redzone",
 794			endobject, val, s->inuse - s->objsize))
 795			return 0;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 796	} else {
 797		if ((s->flags & SLAB_POISON) && s->objsize < s->inuse) {
 798			check_bytes_and_report(s, page, p, "Alignment padding",
 799				endobject, POISON_INUSE, s->inuse - s->objsize);
 
 
 800		}
 801	}
 802
 803	if (s->flags & SLAB_POISON) {
 804		if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
 805			(!check_bytes_and_report(s, page, p, "Poison", p,
 806					POISON_FREE, s->objsize - 1) ||
 807			 !check_bytes_and_report(s, page, p, "Poison",
 808				p + s->objsize - 1, POISON_END, 1)))
 809			return 0;
 
 
 
 
 
 
 
 
 
 
 
 810		/*
 811		 * check_pad_bytes cleans up on its own.
 812		 */
 813		check_pad_bytes(s, page, p);
 
 814	}
 815
 816	if (!s->offset && val == SLUB_RED_ACTIVE)
 817		/*
 818		 * Object and freepointer overlap. Cannot check
 819		 * freepointer while object is allocated.
 820		 */
 821		return 1;
 822
 823	/* Check free pointer validity */
 824	if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
 825		object_err(s, page, p, "Freepointer corrupt");
 826		/*
 827		 * No choice but to zap it and thus lose the remainder
 828		 * of the free objects in this slab. May cause
 829		 * another error because the object count is now wrong.
 830		 */
 831		set_freepointer(s, p, NULL);
 832		return 0;
 833	}
 834	return 1;
 
 
 
 
 
 
 835}
 836
 837static int check_slab(struct kmem_cache *s, struct page *page)
 838{
 839	int maxobj;
 840
 841	VM_BUG_ON(!irqs_disabled());
 842
 843	if (!PageSlab(page)) {
 844		slab_err(s, page, "Not a valid slab page");
 845		return 0;
 846	}
 847
 848	maxobj = order_objects(compound_order(page), s->size, s->reserved);
 849	if (page->objects > maxobj) {
 850		slab_err(s, page, "objects %u > max %u",
 851			s->name, page->objects, maxobj);
 852		return 0;
 853	}
 854	if (page->inuse > page->objects) {
 855		slab_err(s, page, "inuse %u > max %u",
 856			s->name, page->inuse, page->objects);
 857		return 0;
 858	}
 
 
 
 
 
 859	/* Slab_pad_check fixes things up after itself */
 860	slab_pad_check(s, page);
 861	return 1;
 862}
 863
 864/*
 865 * Determine if a certain object on a page is on the freelist. Must hold the
 866 * slab lock to guarantee that the chains are in a consistent state.
 867 */
 868static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
 869{
 870	int nr = 0;
 871	void *fp;
 872	void *object = NULL;
 873	unsigned long max_objects;
 874
 875	fp = page->freelist;
 876	while (fp && nr <= page->objects) {
 877		if (fp == search)
 878			return 1;
 879		if (!check_valid_pointer(s, page, fp)) {
 880			if (object) {
 881				object_err(s, page, object,
 882					"Freechain corrupt");
 883				set_freepointer(s, object, NULL);
 884				break;
 885			} else {
 886				slab_err(s, page, "Freepointer corrupt");
 887				page->freelist = NULL;
 888				page->inuse = page->objects;
 889				slab_fix(s, "Freelist cleared");
 890				return 0;
 891			}
 892			break;
 893		}
 894		object = fp;
 895		fp = get_freepointer(s, object);
 896		nr++;
 897	}
 898
 899	max_objects = order_objects(compound_order(page), s->size, s->reserved);
 900	if (max_objects > MAX_OBJS_PER_PAGE)
 901		max_objects = MAX_OBJS_PER_PAGE;
 902
 903	if (page->objects != max_objects) {
 904		slab_err(s, page, "Wrong number of objects. Found %d but "
 905			"should be %d", page->objects, max_objects);
 906		page->objects = max_objects;
 907		slab_fix(s, "Number of objects adjusted.");
 908	}
 909	if (page->inuse != page->objects - nr) {
 910		slab_err(s, page, "Wrong object count. Counter is %d but "
 911			"counted were %d", page->inuse, page->objects - nr);
 912		page->inuse = page->objects - nr;
 913		slab_fix(s, "Object count adjusted.");
 914	}
 915	return search == NULL;
 916}
 917
 918static void trace(struct kmem_cache *s, struct page *page, void *object,
 919								int alloc)
 920{
 921	if (s->flags & SLAB_TRACE) {
 922		printk(KERN_INFO "TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
 923			s->name,
 924			alloc ? "alloc" : "free",
 925			object, page->inuse,
 926			page->freelist);
 927
 928		if (!alloc)
 929			print_section("Object ", (void *)object, s->objsize);
 
 930
 931		dump_stack();
 932	}
 933}
 934
 935/*
 936 * Hooks for other subsystems that check memory allocations. In a typical
 937 * production configuration these hooks all should produce no code at all.
 938 */
 939static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
 940{
 941	flags &= gfp_allowed_mask;
 942	lockdep_trace_alloc(flags);
 943	might_sleep_if(flags & __GFP_WAIT);
 944
 945	return should_failslab(s->objsize, flags, s->flags);
 946}
 947
 948static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags, void *object)
 949{
 950	flags &= gfp_allowed_mask;
 951	kmemcheck_slab_alloc(s, flags, object, slab_ksize(s));
 952	kmemleak_alloc_recursive(object, s->objsize, 1, s->flags, flags);
 953}
 954
 955static inline void slab_free_hook(struct kmem_cache *s, void *x)
 956{
 957	kmemleak_free_recursive(x, s->flags);
 958
 959	/*
 960	 * Trouble is that we may no longer disable interupts in the fast path
 961	 * So in order to make the debug calls that expect irqs to be
 962	 * disabled we need to disable interrupts temporarily.
 963	 */
 964#if defined(CONFIG_KMEMCHECK) || defined(CONFIG_LOCKDEP)
 965	{
 966		unsigned long flags;
 967
 968		local_irq_save(flags);
 969		kmemcheck_slab_free(s, x, s->objsize);
 970		debug_check_no_locks_freed(x, s->objsize);
 971		local_irq_restore(flags);
 972	}
 973#endif
 974	if (!(s->flags & SLAB_DEBUG_OBJECTS))
 975		debug_check_no_obj_freed(x, s->objsize);
 976}
 977
 978/*
 979 * Tracking of fully allocated slabs for debugging purposes.
 980 *
 981 * list_lock must be held.
 982 */
 983static void add_full(struct kmem_cache *s,
 984	struct kmem_cache_node *n, struct page *page)
 985{
 986	if (!(s->flags & SLAB_STORE_USER))
 987		return;
 988
 989	list_add(&page->lru, &n->full);
 
 990}
 991
 992/*
 993 * list_lock must be held.
 994 */
 995static void remove_full(struct kmem_cache *s, struct page *page)
 996{
 997	if (!(s->flags & SLAB_STORE_USER))
 998		return;
 999
1000	list_del(&page->lru);
1001}
1002
1003/* Tracking of the number of slabs for debugging purposes */
1004static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1005{
1006	struct kmem_cache_node *n = get_node(s, node);
1007
1008	return atomic_long_read(&n->nr_slabs);
1009}
1010
1011static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1012{
1013	return atomic_long_read(&n->nr_slabs);
1014}
1015
1016static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
1017{
1018	struct kmem_cache_node *n = get_node(s, node);
1019
1020	/*
1021	 * May be called early in order to allocate a slab for the
1022	 * kmem_cache_node structure. Solve the chicken-egg
1023	 * dilemma by deferring the increment of the count during
1024	 * bootstrap (see early_kmem_cache_node_alloc).
1025	 */
1026	if (n) {
1027		atomic_long_inc(&n->nr_slabs);
1028		atomic_long_add(objects, &n->total_objects);
1029	}
1030}
1031static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
1032{
1033	struct kmem_cache_node *n = get_node(s, node);
1034
1035	atomic_long_dec(&n->nr_slabs);
1036	atomic_long_sub(objects, &n->total_objects);
1037}
1038
1039/* Object debug checks for alloc/free paths */
1040static void setup_object_debug(struct kmem_cache *s, struct page *page,
1041								void *object)
1042{
1043	if (!(s->flags & (SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON)))
1044		return;
1045
1046	init_object(s, object, SLUB_RED_INACTIVE);
1047	init_tracking(s, object);
1048}
1049
1050static noinline int alloc_debug_processing(struct kmem_cache *s, struct page *page,
1051					void *object, unsigned long addr)
1052{
1053	if (!check_slab(s, page))
1054		goto bad;
 
 
 
 
 
1055
1056	if (!check_valid_pointer(s, page, object)) {
1057		object_err(s, page, object, "Freelist Pointer check fails");
1058		goto bad;
 
 
 
 
 
 
1059	}
1060
1061	if (!check_object(s, page, object, SLUB_RED_INACTIVE))
1062		goto bad;
1063
1064	/* Success perform special debug activities for allocs */
1065	if (s->flags & SLAB_STORE_USER)
1066		set_track(s, object, TRACK_ALLOC, addr);
1067	trace(s, page, object, 1);
1068	init_object(s, object, SLUB_RED_ACTIVE);
1069	return 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1070
1071bad:
1072	if (PageSlab(page)) {
1073		/*
1074		 * If this is a slab page then lets do the best we can
1075		 * to avoid issues in the future. Marking all objects
1076		 * as used avoids touching the remaining objects.
1077		 */
1078		slab_fix(s, "Marking all objects used");
1079		page->inuse = page->objects;
1080		page->freelist = NULL;
 
1081	}
1082	return 0;
1083}
1084
1085static noinline int free_debug_processing(struct kmem_cache *s,
1086		 struct page *page, void *object, unsigned long addr)
1087{
1088	unsigned long flags;
1089	int rc = 0;
1090
1091	local_irq_save(flags);
1092	slab_lock(page);
1093
1094	if (!check_slab(s, page))
1095		goto fail;
1096
1097	if (!check_valid_pointer(s, page, object)) {
1098		slab_err(s, page, "Invalid object pointer 0x%p", object);
1099		goto fail;
1100	}
1101
1102	if (on_freelist(s, page, object)) {
1103		object_err(s, page, object, "Object already free");
1104		goto fail;
1105	}
1106
1107	if (!check_object(s, page, object, SLUB_RED_ACTIVE))
1108		goto out;
1109
1110	if (unlikely(s != page->slab)) {
1111		if (!PageSlab(page)) {
1112			slab_err(s, page, "Attempt to free object(0x%p) "
1113				"outside of slab", object);
1114		} else if (!page->slab) {
1115			printk(KERN_ERR
1116				"SLUB <none>: no slab for object 0x%p.\n",
1117						object);
1118			dump_stack();
1119		} else
1120			object_err(s, page, object,
1121					"page slab pointer corrupt.");
1122		goto fail;
1123	}
1124
1125	if (s->flags & SLAB_STORE_USER)
1126		set_track(s, object, TRACK_FREE, addr);
1127	trace(s, page, object, 0);
1128	init_object(s, object, SLUB_RED_INACTIVE);
1129	rc = 1;
1130out:
1131	slab_unlock(page);
1132	local_irq_restore(flags);
1133	return rc;
1134
1135fail:
1136	slab_fix(s, "Object at 0x%p not freed", object);
1137	goto out;
1138}
1139
1140static int __init setup_slub_debug(char *str)
 
 
 
 
 
 
 
 
 
 
 
1141{
1142	slub_debug = DEBUG_DEFAULT_FLAGS;
1143	if (*str++ != '=' || !*str)
1144		/*
1145		 * No options specified. Switch on full debugging.
1146		 */
1147		goto out;
1148
1149	if (*str == ',')
 
 
 
 
1150		/*
1151		 * No options but restriction on slabs. This means full
1152		 * debugging for slabs matching a pattern.
1153		 */
 
1154		goto check_slabs;
1155
1156	if (tolower(*str) == 'o') {
1157		/*
1158		 * Avoid enabling debugging on caches if its minimum order
1159		 * would increase as a result.
1160		 */
1161		disable_higher_order_debug = 1;
1162		goto out;
1163	}
 
1164
1165	slub_debug = 0;
1166	if (*str == '-')
1167		/*
1168		 * Switch off all debugging measures.
1169		 */
1170		goto out;
1171
1172	/*
1173	 * Determine which debug features should be switched on
1174	 */
1175	for (; *str && *str != ','; str++) {
1176		switch (tolower(*str)) {
 
 
 
1177		case 'f':
1178			slub_debug |= SLAB_DEBUG_FREE;
1179			break;
1180		case 'z':
1181			slub_debug |= SLAB_RED_ZONE;
1182			break;
1183		case 'p':
1184			slub_debug |= SLAB_POISON;
1185			break;
1186		case 'u':
1187			slub_debug |= SLAB_STORE_USER;
1188			break;
1189		case 't':
1190			slub_debug |= SLAB_TRACE;
1191			break;
1192		case 'a':
1193			slub_debug |= SLAB_FAILSLAB;
 
 
 
 
 
 
 
1194			break;
1195		default:
1196			printk(KERN_ERR "slub_debug option '%c' "
1197				"unknown. skipped\n", *str);
1198		}
1199	}
1200
1201check_slabs:
1202	if (*str == ',')
1203		slub_debug_slabs = str + 1;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1204out:
 
 
 
 
 
 
 
 
 
 
 
1205	return 1;
1206}
1207
1208__setup("slub_debug", setup_slub_debug);
 
1209
1210static unsigned long kmem_cache_flags(unsigned long objsize,
1211	unsigned long flags, const char *name,
1212	void (*ctor)(void *))
 
 
 
 
 
 
 
 
1213{
 
 
 
 
 
 
 
 
 
1214	/*
1215	 * Enable debugging if selected on the kernel commandline.
 
 
1216	 */
1217	if (slub_debug && (!slub_debug_slabs ||
1218		!strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs))))
1219		flags |= slub_debug;
1220
1221	return flags;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1222}
1223#else
1224static inline void setup_object_debug(struct kmem_cache *s,
1225			struct page *page, void *object) {}
 
1226
1227static inline int alloc_debug_processing(struct kmem_cache *s,
1228	struct page *page, void *object, unsigned long addr) { return 0; }
1229
1230static inline int free_debug_processing(struct kmem_cache *s,
1231	struct page *page, void *object, unsigned long addr) { return 0; }
 
1232
1233static inline int slab_pad_check(struct kmem_cache *s, struct page *page)
1234			{ return 1; }
1235static inline int check_object(struct kmem_cache *s, struct page *page,
1236			void *object, u8 val) { return 1; }
 
 
 
1237static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
1238					struct page *page) {}
1239static inline void remove_full(struct kmem_cache *s, struct page *page) {}
1240static inline unsigned long kmem_cache_flags(unsigned long objsize,
1241	unsigned long flags, const char *name,
1242	void (*ctor)(void *))
1243{
1244	return flags;
1245}
1246#define slub_debug 0
1247
1248#define disable_higher_order_debug 0
1249
1250static inline unsigned long slabs_node(struct kmem_cache *s, int node)
1251							{ return 0; }
1252static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
1253							{ return 0; }
1254static inline void inc_slabs_node(struct kmem_cache *s, int node,
1255							int objects) {}
1256static inline void dec_slabs_node(struct kmem_cache *s, int node,
1257							int objects) {}
 
 
 
 
 
 
 
 
1258
1259static inline int slab_pre_alloc_hook(struct kmem_cache *s, gfp_t flags)
1260							{ return 0; }
1261
1262static inline void slab_post_alloc_hook(struct kmem_cache *s, gfp_t flags,
1263		void *object) {}
1264
1265static inline void slab_free_hook(struct kmem_cache *s, void *x) {}
 
 
 
1266
1267#endif /* CONFIG_SLUB_DEBUG */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1268
1269/*
1270 * Slab allocation and freeing
 
 
1271 */
1272static inline struct page *alloc_slab_page(gfp_t flags, int node,
1273					struct kmem_cache_order_objects oo)
 
 
 
1274{
1275	int order = oo_order(oo);
 
 
 
1276
1277	flags |= __GFP_NOTRACK;
 
 
 
 
 
 
 
 
1278
1279	if (node == NUMA_NO_NODE)
1280		return alloc_pages(flags, order);
1281	else
1282		return alloc_pages_exact_node(node, flags, order);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1283}
1284
1285static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
1286{
1287	struct page *page;
1288	struct kmem_cache_order_objects oo = s->oo;
1289	gfp_t alloc_gfp;
1290
1291	flags &= gfp_allowed_mask;
 
 
1292
1293	if (flags & __GFP_WAIT)
1294		local_irq_enable();
 
 
 
 
 
 
 
 
 
1295
1296	flags |= s->allocflags;
 
 
 
1297
1298	/*
1299	 * Let the initial higher-order allocation fail under memory pressure
1300	 * so we fall-back to the minimum order allocation.
1301	 */
1302	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
 
1303
1304	page = alloc_slab_page(alloc_gfp, node, oo);
1305	if (unlikely(!page)) {
1306		oo = s->min;
1307		/*
1308		 * Allocation may have failed due to fragmentation.
1309		 * Try a lower order alloc if possible
1310		 */
1311		page = alloc_slab_page(flags, node, oo);
1312
1313		if (page)
1314			stat(s, ORDER_FALLBACK);
1315	}
 
 
 
 
 
 
 
 
 
 
 
1316
1317	if (flags & __GFP_WAIT)
1318		local_irq_disable();
1319
1320	if (!page)
 
 
 
 
 
 
 
1321		return NULL;
1322
1323	if (kmemcheck_enabled
1324		&& !(s->flags & (SLAB_NOTRACK | DEBUG_DEFAULT_FLAGS))) {
1325		int pages = 1 << oo_order(oo);
1326
1327		kmemcheck_alloc_shadow(page, oo_order(oo), flags, node);
 
 
 
 
 
 
 
 
 
 
 
1328
 
 
 
 
 
 
 
1329		/*
1330		 * Objects from caches that have a constructor don't get
1331		 * cleared when they're allocated, so we need to do it here.
 
1332		 */
1333		if (s->ctor)
1334			kmemcheck_mark_uninitialized_pages(page, pages);
1335		else
1336			kmemcheck_mark_unallocated_pages(page, pages);
1337	}
 
 
 
 
 
 
 
 
1338
1339	page->objects = oo_objects(oo);
1340	mod_zone_page_state(page_zone(page),
1341		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
1342		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1343		1 << oo_order(oo));
 
1344
1345	return page;
 
 
 
 
 
 
 
 
1346}
1347
1348static void setup_object(struct kmem_cache *s, struct page *page,
1349				void *object)
 
 
1350{
1351	setup_object_debug(s, page, object);
1352	if (unlikely(s->ctor))
1353		s->ctor(object);
1354}
1355
1356static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
 
 
1357{
1358	struct page *page;
1359	void *start;
1360	void *last;
1361	void *p;
1362
1363	BUG_ON(flags & GFP_SLAB_BUG_MASK);
1364
1365	page = allocate_slab(s,
1366		flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
1367	if (!page)
1368		goto out;
1369
1370	inc_slabs_node(s, page_to_nid(page), page->objects);
1371	page->slab = s;
1372	__SetPageSlab(page);
1373
1374	start = page_address(page);
1375
1376	if (unlikely(s->flags & SLAB_POISON))
1377		memset(start, POISON_INUSE, PAGE_SIZE << compound_order(page));
1378
1379	last = start;
1380	for_each_object(p, s, start, page->objects) {
1381		setup_object(s, page, last);
1382		set_freepointer(s, last, p);
1383		last = p;
1384	}
1385	setup_object(s, page, last);
1386	set_freepointer(s, last, NULL);
1387
1388	page->freelist = start;
1389	page->inuse = page->objects;
1390	page->frozen = 1;
1391out:
1392	return page;
 
 
1393}
1394
1395static void __free_slab(struct kmem_cache *s, struct page *page)
 
 
1396{
1397	int order = compound_order(page);
1398	int pages = 1 << order;
1399
1400	if (kmem_cache_debug(s)) {
1401		void *p;
 
 
 
 
 
 
 
1402
1403		slab_pad_check(s, page);
1404		for_each_object(p, s, page_address(page),
1405						page->objects)
1406			check_object(s, page, p, SLUB_RED_INACTIVE);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1407	}
1408
1409	kmemcheck_free_shadow(page, compound_order(page));
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1410
1411	mod_zone_page_state(page_zone(page),
1412		(s->flags & SLAB_RECLAIM_ACCOUNT) ?
1413		NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
1414		-pages);
1415
1416	__ClearPageSlab(page);
1417	reset_page_mapcount(page);
1418	if (current->reclaim_state)
1419		current->reclaim_state->reclaimed_slab += pages;
1420	__free_pages(page, order);
 
 
1421}
1422
1423#define need_reserve_slab_rcu						\
1424	(sizeof(((struct page *)NULL)->lru) < sizeof(struct rcu_head))
 
 
1425
1426static void rcu_free_slab(struct rcu_head *h)
1427{
1428	struct page *page;
 
 
1429
1430	if (need_reserve_slab_rcu)
1431		page = virt_to_head_page(h);
1432	else
1433		page = container_of((struct list_head *)h, struct page, lru);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1434
1435	__free_slab(page->slab, page);
 
 
1436}
1437
1438static void free_slab(struct kmem_cache *s, struct page *page)
 
 
1439{
1440	if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
1441		struct rcu_head *head;
1442
1443		if (need_reserve_slab_rcu) {
1444			int order = compound_order(page);
1445			int offset = (PAGE_SIZE << order) - s->reserved;
 
 
 
 
 
 
1446
1447			VM_BUG_ON(s->reserved != sizeof(*head));
1448			head = page_address(page) + offset;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1449		} else {
1450			/*
1451			 * RCU free overloads the RCU head over the LRU
 
1452			 */
1453			head = (void *)&page->lru;
1454		}
 
1455
1456		call_rcu(head, rcu_free_slab);
1457	} else
1458		__free_slab(s, page);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1459}
1460
1461static void discard_slab(struct kmem_cache *s, struct page *page)
1462{
1463	dec_slabs_node(s, page_to_nid(page), page->objects);
1464	free_slab(s, page);
 
 
 
 
1465}
1466
1467/*
1468 * Management of partially allocated slabs.
1469 *
1470 * list_lock must be held.
1471 */
1472static inline void add_partial(struct kmem_cache_node *n,
1473				struct page *page, int tail)
1474{
1475	n->nr_partial++;
1476	if (tail == DEACTIVATE_TO_TAIL)
1477		list_add_tail(&page->lru, &n->partial);
1478	else
1479		list_add(&page->lru, &n->partial);
 
 
 
 
 
 
 
 
1480}
1481
1482/*
1483 * list_lock must be held.
1484 */
1485static inline void remove_partial(struct kmem_cache_node *n,
1486					struct page *page)
1487{
1488	list_del(&page->lru);
 
 
1489	n->nr_partial--;
1490}
1491
1492/*
1493 * Lock slab, remove from the partial list and put the object into the
1494 * per cpu freelist.
1495 *
1496 * Returns a list of objects or NULL if it fails.
1497 *
1498 * Must hold list_lock.
1499 */
1500static inline void *acquire_slab(struct kmem_cache *s,
1501		struct kmem_cache_node *n, struct page *page,
1502		int mode)
1503{
1504	void *freelist;
1505	unsigned long counters;
1506	struct page new;
1507
1508	/*
1509	 * Zap the freelist and set the frozen bit.
1510	 * The old freelist is the list of objects for the
1511	 * per cpu allocation list.
1512	 */
1513	do {
1514		freelist = page->freelist;
1515		counters = page->counters;
1516		new.counters = counters;
1517		if (mode) {
1518			new.inuse = page->objects;
1519			new.freelist = NULL;
1520		} else {
1521			new.freelist = freelist;
1522		}
1523
1524		VM_BUG_ON(new.frozen);
1525		new.frozen = 1;
 
 
 
 
 
 
 
1526
1527	} while (!__cmpxchg_double_slab(s, page,
1528			freelist, counters,
1529			new.freelist, new.counters,
1530			"lock and freeze"));
1531
1532	remove_partial(n, page);
1533	return freelist;
1534}
1535
1536static int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1537
1538/*
1539 * Try to allocate a partial slab from a specific node.
1540 */
1541static void *get_partial_node(struct kmem_cache *s,
1542		struct kmem_cache_node *n, struct kmem_cache_cpu *c)
 
1543{
1544	struct page *page, *page2;
1545	void *object = NULL;
 
1546
1547	/*
1548	 * Racy check. If we mistakenly see no partial slabs then we
1549	 * just allocate an empty slab. If we mistakenly try to get a
1550	 * partial slab and there is none available then get_partials()
1551	 * will return NULL.
1552	 */
1553	if (!n || !n->nr_partial)
1554		return NULL;
1555
1556	spin_lock(&n->list_lock);
1557	list_for_each_entry_safe(page, page2, &n->partial, lru) {
1558		void *t = acquire_slab(s, n, page, object == NULL);
1559		int available;
1560
1561		if (!t)
1562			break;
 
 
 
 
 
 
 
 
 
 
1563
1564		if (!object) {
1565			c->page = page;
1566			c->node = page_to_nid(page);
1567			stat(s, ALLOC_FROM_PARTIAL);
1568			object = t;
1569			available =  page->objects - page->inuse;
 
 
1570		} else {
1571			available = put_cpu_partial(s, page, 0);
1572			stat(s, CPU_PARTIAL_NODE);
1573		}
1574		if (kmem_cache_debug(s) || available > s->cpu_partial / 2)
1575			break;
1576
 
 
 
 
1577	}
1578	spin_unlock(&n->list_lock);
1579	return object;
1580}
1581
1582/*
1583 * Get a page from somewhere. Search in increasing NUMA distances.
1584 */
1585static void *get_any_partial(struct kmem_cache *s, gfp_t flags,
1586		struct kmem_cache_cpu *c)
1587{
1588#ifdef CONFIG_NUMA
1589	struct zonelist *zonelist;
1590	struct zoneref *z;
1591	struct zone *zone;
1592	enum zone_type high_zoneidx = gfp_zone(flags);
1593	void *object;
1594	unsigned int cpuset_mems_cookie;
1595
1596	/*
1597	 * The defrag ratio allows a configuration of the tradeoffs between
1598	 * inter node defragmentation and node local allocations. A lower
1599	 * defrag_ratio increases the tendency to do local allocations
1600	 * instead of attempting to obtain partial slabs from other nodes.
1601	 *
1602	 * If the defrag_ratio is set to 0 then kmalloc() always
1603	 * returns node local objects. If the ratio is higher then kmalloc()
1604	 * may return off node objects because partial slabs are obtained
1605	 * from other nodes and filled up.
1606	 *
1607	 * If /sys/kernel/slab/xx/defrag_ratio is set to 100 (which makes
1608	 * defrag_ratio = 1000) then every (well almost) allocation will
1609	 * first attempt to defrag slab caches on other nodes. This means
1610	 * scanning over all nodes to look for partial slabs which may be
1611	 * expensive if we do it every time we are trying to find a slab
1612	 * with available objects.
1613	 */
1614	if (!s->remote_node_defrag_ratio ||
1615			get_cycles() % 1024 > s->remote_node_defrag_ratio)
1616		return NULL;
1617
1618	do {
1619		cpuset_mems_cookie = get_mems_allowed();
1620		zonelist = node_zonelist(slab_node(current->mempolicy), flags);
1621		for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
1622			struct kmem_cache_node *n;
1623
1624			n = get_node(s, zone_to_nid(zone));
1625
1626			if (n && cpuset_zone_allowed_hardwall(zone, flags) &&
1627					n->nr_partial > s->min_partial) {
1628				object = get_partial_node(s, n, c);
1629				if (object) {
1630					/*
1631					 * Return the object even if
1632					 * put_mems_allowed indicated that
1633					 * the cpuset mems_allowed was
1634					 * updated in parallel. It's a
1635					 * harmless race between the alloc
1636					 * and the cpuset update.
1637					 */
1638					put_mems_allowed(cpuset_mems_cookie);
1639					return object;
1640				}
1641			}
1642		}
1643	} while (!put_mems_allowed(cpuset_mems_cookie));
1644#endif
1645	return NULL;
1646}
1647
1648/*
1649 * Get a partial page, lock it and return it.
1650 */
1651static void *get_partial(struct kmem_cache *s, gfp_t flags, int node,
1652		struct kmem_cache_cpu *c)
1653{
1654	void *object;
1655	int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node;
 
 
 
1656
1657	object = get_partial_node(s, get_node(s, searchnode), c);
1658	if (object || node != NUMA_NO_NODE)
1659		return object;
1660
1661	return get_any_partial(s, flags, c);
1662}
1663
1664#ifdef CONFIG_PREEMPT
 
 
1665/*
1666 * Calculate the next globally unique transaction for disambiguiation
1667 * during cmpxchg. The transactions start with the cpu number and are then
1668 * incremented by CONFIG_NR_CPUS.
1669 */
1670#define TID_STEP  roundup_pow_of_two(CONFIG_NR_CPUS)
1671#else
1672/*
1673 * No preemption supported therefore also no need to check for
1674 * different cpus.
1675 */
1676#define TID_STEP 1
1677#endif
1678
1679static inline unsigned long next_tid(unsigned long tid)
1680{
1681	return tid + TID_STEP;
1682}
1683
 
1684static inline unsigned int tid_to_cpu(unsigned long tid)
1685{
1686	return tid % TID_STEP;
1687}
1688
1689static inline unsigned long tid_to_event(unsigned long tid)
1690{
1691	return tid / TID_STEP;
1692}
 
1693
1694static inline unsigned int init_tid(int cpu)
1695{
1696	return cpu;
1697}
1698
1699static inline void note_cmpxchg_failure(const char *n,
1700		const struct kmem_cache *s, unsigned long tid)
1701{
1702#ifdef SLUB_DEBUG_CMPXCHG
1703	unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
1704
1705	printk(KERN_INFO "%s %s: cmpxchg redo ", n, s->name);
1706
1707#ifdef CONFIG_PREEMPT
1708	if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
1709		printk("due to cpu change %d -> %d\n",
1710			tid_to_cpu(tid), tid_to_cpu(actual_tid));
1711	else
1712#endif
1713	if (tid_to_event(tid) != tid_to_event(actual_tid))
1714		printk("due to cpu running other code. Event %ld->%ld\n",
1715			tid_to_event(tid), tid_to_event(actual_tid));
1716	else
1717		printk("for unknown reason: actual=%lx was=%lx target=%lx\n",
1718			actual_tid, tid, next_tid(tid));
1719#endif
1720	stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
1721}
1722
1723void init_kmem_cache_cpus(struct kmem_cache *s)
1724{
1725	int cpu;
 
1726
1727	for_each_possible_cpu(cpu)
1728		per_cpu_ptr(s->cpu_slab, cpu)->tid = init_tid(cpu);
 
 
 
1729}
1730
1731/*
1732 * Remove the cpu slab
 
 
 
1733 */
1734static void deactivate_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
 
1735{
1736	enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE };
1737	struct page *page = c->page;
1738	struct kmem_cache_node *n = get_node(s, page_to_nid(page));
1739	int lock = 0;
1740	enum slab_modes l = M_NONE, m = M_NONE;
1741	void *freelist;
1742	void *nextfree;
1743	int tail = DEACTIVATE_TO_HEAD;
1744	struct page new;
1745	struct page old;
 
1746
1747	if (page->freelist) {
1748		stat(s, DEACTIVATE_REMOTE_FREES);
1749		tail = DEACTIVATE_TO_TAIL;
1750	}
1751
1752	c->tid = next_tid(c->tid);
1753	c->page = NULL;
1754	freelist = c->freelist;
1755	c->freelist = NULL;
1756
1757	/*
1758	 * Stage one: Free all available per cpu objects back
1759	 * to the page freelist while it is still frozen. Leave the
1760	 * last one.
1761	 *
1762	 * There is no need to take the list->lock because the page
1763	 * is still frozen.
1764	 */
1765	while (freelist && (nextfree = get_freepointer(s, freelist))) {
1766		void *prior;
1767		unsigned long counters;
 
1768
1769		do {
1770			prior = page->freelist;
1771			counters = page->counters;
1772			set_freepointer(s, freelist, prior);
1773			new.counters = counters;
1774			new.inuse--;
1775			VM_BUG_ON(!new.frozen);
1776
1777		} while (!__cmpxchg_double_slab(s, page,
1778			prior, counters,
1779			freelist, new.counters,
1780			"drain percpu freelist"));
1781
1782		freelist = nextfree;
1783	}
1784
1785	/*
1786	 * Stage two: Ensure that the page is unfrozen while the
1787	 * list presence reflects the actual number of objects
1788	 * during unfreeze.
1789	 *
1790	 * We setup the list membership and then perform a cmpxchg
1791	 * with the count. If there is a mismatch then the page
1792	 * is not unfrozen but the page is on the wrong list.
1793	 *
1794	 * Then we restart the process which may have to remove
1795	 * the page from the list that we just put it on again
1796	 * because the number of objects in the slab may have
1797	 * changed.
1798	 */
1799redo:
1800
1801	old.freelist = page->freelist;
1802	old.counters = page->counters;
1803	VM_BUG_ON(!old.frozen);
1804
1805	/* Determine target state of the slab */
1806	new.counters = old.counters;
1807	if (freelist) {
1808		new.inuse--;
1809		set_freepointer(s, freelist, old.freelist);
1810		new.freelist = freelist;
1811	} else
1812		new.freelist = old.freelist;
1813
1814	new.frozen = 0;
1815
1816	if (!new.inuse && n->nr_partial > s->min_partial)
1817		m = M_FREE;
1818	else if (new.freelist) {
1819		m = M_PARTIAL;
1820		if (!lock) {
1821			lock = 1;
1822			/*
1823			 * Taking the spinlock removes the possiblity
1824			 * that acquire_slab() will see a slab page that
1825			 * is frozen
1826			 */
1827			spin_lock(&n->list_lock);
1828		}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1829	} else {
1830		m = M_FULL;
1831		if (kmem_cache_debug(s) && !lock) {
1832			lock = 1;
1833			/*
1834			 * This also ensures that the scanning of full
1835			 * slabs from diagnostic functions will not see
1836			 * any frozen slabs.
1837			 */
1838			spin_lock(&n->list_lock);
1839		}
1840	}
 
1841
1842	if (l != m) {
1843
1844		if (l == M_PARTIAL)
1845
1846			remove_partial(n, page);
1847
1848		else if (l == M_FULL)
1849
1850			remove_full(s, page);
1851
1852		if (m == M_PARTIAL) {
1853
1854			add_partial(n, page, tail);
1855			stat(s, tail);
 
1856
1857		} else if (m == M_FULL) {
 
 
 
1858
1859			stat(s, DEACTIVATE_FULL);
1860			add_full(s, n, page);
 
1861
 
 
 
 
 
 
1862		}
1863	}
1864
1865	l = m;
1866	if (!__cmpxchg_double_slab(s, page,
1867				old.freelist, old.counters,
1868				new.freelist, new.counters,
1869				"unfreezing slab"))
1870		goto redo;
1871
1872	if (lock)
1873		spin_unlock(&n->list_lock);
 
1874
1875	if (m == M_FREE) {
1876		stat(s, DEACTIVATE_EMPTY);
1877		discard_slab(s, page);
1878		stat(s, FREE_SLAB);
1879	}
1880}
1881
1882/* Unfreeze all the cpu partial slabs */
1883static void unfreeze_partials(struct kmem_cache *s)
 
 
1884{
1885	struct kmem_cache_node *n = NULL;
1886	struct kmem_cache_cpu *c = this_cpu_ptr(s->cpu_slab);
1887	struct page *page, *discard_page = NULL;
1888
1889	while ((page = c->partial)) {
1890		enum slab_modes { M_PARTIAL, M_FREE };
1891		enum slab_modes l, m;
1892		struct page new;
1893		struct page old;
1894
1895		c->partial = page->next;
1896		l = M_FREE;
1897
1898		do {
 
 
 
1899
1900			old.freelist = page->freelist;
1901			old.counters = page->counters;
1902			VM_BUG_ON(!old.frozen);
1903
1904			new.counters = old.counters;
1905			new.freelist = old.freelist;
 
 
1906
1907			new.frozen = 0;
 
1908
1909			if (!new.inuse && (!n || n->nr_partial > s->min_partial))
1910				m = M_FREE;
1911			else {
1912				struct kmem_cache_node *n2 = get_node(s,
1913							page_to_nid(page));
1914
1915				m = M_PARTIAL;
1916				if (n != n2) {
1917					if (n)
1918						spin_unlock(&n->list_lock);
1919
1920					n = n2;
1921					spin_lock(&n->list_lock);
1922				}
1923			}
 
 
 
 
 
 
 
 
1924
1925			if (l != m) {
1926				if (l == M_PARTIAL) {
1927					remove_partial(n, page);
1928					stat(s, FREE_REMOVE_PARTIAL);
1929				} else {
1930					add_partial(n, page,
1931						DEACTIVATE_TO_TAIL);
1932					stat(s, FREE_ADD_PARTIAL);
1933				}
1934
1935				l = m;
1936			}
1937
1938		} while (!cmpxchg_double_slab(s, page,
1939				old.freelist, old.counters,
1940				new.freelist, new.counters,
1941				"unfreezing slab"));
1942
1943		if (m == M_FREE) {
1944			page->next = discard_page;
1945			discard_page = page;
 
 
 
1946		}
1947	}
1948
1949	if (n)
1950		spin_unlock(&n->list_lock);
1951
1952	while (discard_page) {
1953		page = discard_page;
1954		discard_page = discard_page->next;
1955
1956		stat(s, DEACTIVATE_EMPTY);
1957		discard_slab(s, page);
1958		stat(s, FREE_SLAB);
 
 
 
 
1959	}
1960}
1961
1962/*
1963 * Put a page that was just frozen (in __slab_free) into a partial page
1964 * slot if available. This is done without interrupts disabled and without
1965 * preemption disabled. The cmpxchg is racy and may put the partial page
1966 * onto a random cpus partial slot.
1967 *
1968 * If we did not find a slot then simply move all the partials to the
1969 * per node partial list.
1970 */
1971int put_cpu_partial(struct kmem_cache *s, struct page *page, int drain)
1972{
1973	struct page *oldpage;
1974	int pages;
1975	int pobjects;
1976
1977	do {
1978		pages = 0;
1979		pobjects = 0;
1980		oldpage = this_cpu_read(s->cpu_slab->partial);
1981
1982		if (oldpage) {
1983			pobjects = oldpage->pobjects;
1984			pages = oldpage->pages;
1985			if (drain && pobjects > s->cpu_partial) {
1986				unsigned long flags;
1987				/*
1988				 * partial array is full. Move the existing
1989				 * set to the per node partial list.
1990				 */
1991				local_irq_save(flags);
1992				unfreeze_partials(s);
1993				local_irq_restore(flags);
1994				pobjects = 0;
1995				pages = 0;
1996				stat(s, CPU_PARTIAL_DRAIN);
1997			}
1998		}
1999
2000		pages++;
2001		pobjects += page->objects - page->inuse;
2002
2003		page->pages = pages;
2004		page->pobjects = pobjects;
2005		page->next = oldpage;
 
 
2006
2007	} while (this_cpu_cmpxchg(s->cpu_slab->partial, oldpage, page) != oldpage);
2008	return pobjects;
 
 
2009}
2010
2011static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
2012{
2013	stat(s, CPUSLAB_FLUSH);
2014	deactivate_slab(s, c);
 
 
 
 
 
 
 
 
 
 
 
 
2015}
2016
 
 
 
 
 
 
2017/*
2018 * Flush cpu slab.
2019 *
2020 * Called from IPI handler with interrupts disabled.
2021 */
2022static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
2023{
2024	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
 
 
2025
2026	if (likely(c)) {
2027		if (c->page)
2028			flush_slab(s, c);
2029
2030		unfreeze_partials(s);
2031	}
 
 
 
 
 
2032}
2033
2034static void flush_cpu_slab(void *d)
2035{
2036	struct kmem_cache *s = d;
2037
2038	__flush_cpu_slab(s, smp_processor_id());
2039}
2040
2041static bool has_cpu_slab(int cpu, void *info)
 
 
 
2042{
2043	struct kmem_cache *s = info;
2044	struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
2045
2046	return c->page || c->partial;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2047}
2048
2049static void flush_all(struct kmem_cache *s)
2050{
2051	on_each_cpu_cond(has_cpu_slab, flush_cpu_slab, s, 1, GFP_ATOMIC);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2052}
2053
 
 
 
 
 
 
 
2054/*
2055 * Check if the objects in a per cpu structure fit numa
2056 * locality expectations.
2057 */
2058static inline int node_match(struct kmem_cache_cpu *c, int node)
2059{
2060#ifdef CONFIG_NUMA
2061	if (node != NUMA_NO_NODE && c->node != node)
2062		return 0;
2063#endif
2064	return 1;
2065}
2066
2067static int count_free(struct page *page)
 
 
 
 
 
 
2068{
2069	return page->objects - page->inuse;
2070}
2071
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2072static unsigned long count_partial(struct kmem_cache_node *n,
2073					int (*get_count)(struct page *))
2074{
2075	unsigned long flags;
2076	unsigned long x = 0;
2077	struct page *page;
2078
2079	spin_lock_irqsave(&n->list_lock, flags);
2080	list_for_each_entry(page, &n->partial, lru)
2081		x += get_count(page);
2082	spin_unlock_irqrestore(&n->list_lock, flags);
2083	return x;
2084}
 
2085
2086static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
2087{
2088#ifdef CONFIG_SLUB_DEBUG
2089	return atomic_long_read(&n->total_objects);
2090#else
2091	return 0;
2092#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2093}
2094
2095static noinline void
2096slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
2097{
 
 
 
2098	int node;
 
2099
2100	printk(KERN_WARNING
2101		"SLUB: Unable to allocate memory on node %d (gfp=0x%x)\n",
2102		nid, gfpflags);
2103	printk(KERN_WARNING "  cache: %s, object size: %d, buffer size: %d, "
2104		"default order: %d, min order: %d\n", s->name, s->objsize,
2105		s->size, oo_order(s->oo), oo_order(s->min));
2106
2107	if (oo_order(s->min) > get_order(s->objsize))
2108		printk(KERN_WARNING "  %s debugging increased min order, use "
2109		       "slub_debug=O to disable.\n", s->name);
 
 
2110
2111	for_each_online_node(node) {
2112		struct kmem_cache_node *n = get_node(s, node);
2113		unsigned long nr_slabs;
2114		unsigned long nr_objs;
2115		unsigned long nr_free;
2116
2117		if (!n)
2118			continue;
2119
2120		nr_free  = count_partial(n, count_free);
2121		nr_slabs = node_nr_slabs(n);
2122		nr_objs  = node_nr_objs(n);
2123
2124		printk(KERN_WARNING
2125			"  node %d: slabs: %ld, objs: %ld, free: %ld\n",
2126			node, nr_slabs, nr_objs, nr_free);
2127	}
2128}
 
 
 
 
2129
2130static inline void *new_slab_objects(struct kmem_cache *s, gfp_t flags,
2131			int node, struct kmem_cache_cpu **pc)
2132{
2133	void *object;
2134	struct kmem_cache_cpu *c;
2135	struct page *page = new_slab(s, flags, node);
2136
2137	if (page) {
2138		c = __this_cpu_ptr(s->cpu_slab);
2139		if (c->page)
2140			flush_slab(s, c);
2141
2142		/*
2143		 * No other reference to the page yet so we can
2144		 * muck around with it freely without cmpxchg
2145		 */
2146		object = page->freelist;
2147		page->freelist = NULL;
2148
2149		stat(s, ALLOC_SLAB);
2150		c->node = page_to_nid(page);
2151		c->page = page;
2152		*pc = c;
2153	} else
2154		object = NULL;
 
 
2155
2156	return object;
 
2157}
2158
2159/*
2160 * Check the page->freelist of a page and either transfer the freelist to the per cpu freelist
2161 * or deactivate the page.
2162 *
2163 * The page is still frozen if the return value is not NULL.
2164 *
2165 * If this function returns NULL then the page has been unfrozen.
2166 */
2167static inline void *get_freelist(struct kmem_cache *s, struct page *page)
2168{
2169	struct page new;
2170	unsigned long counters;
2171	void *freelist;
2172
 
 
2173	do {
2174		freelist = page->freelist;
2175		counters = page->counters;
 
2176		new.counters = counters;
2177		VM_BUG_ON(!new.frozen);
2178
2179		new.inuse = page->objects;
2180		new.frozen = freelist != NULL;
2181
2182	} while (!cmpxchg_double_slab(s, page,
2183		freelist, counters,
2184		NULL, new.counters,
2185		"get_freelist"));
2186
2187	return freelist;
2188}
2189
2190/*
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2191 * Slow path. The lockless freelist is empty or we need to perform
2192 * debugging duties.
2193 *
2194 * Processing is still very fast if new objects have been freed to the
2195 * regular freelist. In that case we simply take over the regular freelist
2196 * as the lockless freelist and zap the regular freelist.
2197 *
2198 * If that is not working then we fall back to the partial lists. We take the
2199 * first element of the freelist as the object to allocate now and move the
2200 * rest of the freelist to the lockless freelist.
2201 *
2202 * And if we were unable to get a new slab from the partial slab lists then
2203 * we need to allocate a new slab. This is the slowest path since it involves
2204 * a call to the page allocator and the setup of a new slab.
 
 
 
2205 */
2206static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
2207			  unsigned long addr, struct kmem_cache_cpu *c)
2208{
2209	void **object;
 
2210	unsigned long flags;
 
 
2211
2212	local_irq_save(flags);
2213#ifdef CONFIG_PREEMPT
2214	/*
2215	 * We may have been preempted and rescheduled on a different
2216	 * cpu before disabling interrupts. Need to reload cpu area
2217	 * pointer.
2218	 */
2219	c = this_cpu_ptr(s->cpu_slab);
2220#endif
2221
2222	if (!c->page)
2223		goto new_slab;
2224redo:
2225	if (unlikely(!node_match(c, node))) {
2226		stat(s, ALLOC_NODE_MISMATCH);
2227		deactivate_slab(s, c);
 
 
 
 
 
2228		goto new_slab;
2229	}
2230
2231	/* must check again c->freelist in case of cpu migration or IRQ */
2232	object = c->freelist;
2233	if (object)
2234		goto load_freelist;
 
 
 
 
 
 
 
 
2235
2236	stat(s, ALLOC_SLOWPATH);
 
 
 
 
 
 
2237
2238	object = get_freelist(s, c->page);
 
 
 
 
 
 
 
 
2239
2240	if (!object) {
2241		c->page = NULL;
 
 
 
 
2242		stat(s, DEACTIVATE_BYPASS);
2243		goto new_slab;
2244	}
2245
2246	stat(s, ALLOC_REFILL);
2247
2248load_freelist:
2249	c->freelist = get_freepointer(s, object);
 
 
 
 
 
 
 
 
 
2250	c->tid = next_tid(c->tid);
2251	local_irq_restore(flags);
2252	return object;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2253
2254new_slab:
2255
2256	if (c->partial) {
2257		c->page = c->partial;
2258		c->partial = c->page->next;
2259		c->node = page_to_nid(c->page);
2260		stat(s, CPU_PARTIAL_ALLOC);
2261		c->freelist = NULL;
2262		goto redo;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2263	}
 
2264
2265	/* Then do expensive stuff like retrieving pages from the partial lists */
2266	object = get_partial(s, gfpflags, node, c);
2267
2268	if (unlikely(!object)) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2269
2270		object = new_slab_objects(s, gfpflags, node, &c);
 
2271
2272		if (unlikely(!object)) {
2273			if (!(gfpflags & __GFP_NOWARN) && printk_ratelimit())
2274				slab_out_of_memory(s, gfpflags, node);
2275
2276			local_irq_restore(flags);
2277			return NULL;
 
 
 
 
 
 
 
2278		}
 
 
2279	}
2280
2281	if (likely(!kmem_cache_debug(s)))
2282		goto load_freelist;
2283
2284	/* Only entered in the debug case */
2285	if (!alloc_debug_processing(s, c->page, object, addr))
2286		goto new_slab;	/* Slab failed checks. Next slab needed */
2287
2288	c->freelist = get_freepointer(s, object);
2289	deactivate_slab(s, c);
2290	c->node = NUMA_NO_NODE;
2291	local_irq_restore(flags);
2292	return object;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2293}
2294
2295/*
2296 * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
2297 * have the fastpath folded into their functions. So no function call
2298 * overhead for requests that can be satisfied on the fastpath.
2299 *
2300 * The fastpath works by first checking if the lockless freelist can be used.
2301 * If not then __slab_alloc is called for slow processing.
2302 *
2303 * Otherwise we can simply pick the next object from the lockless free list.
2304 */
2305static __always_inline void *slab_alloc(struct kmem_cache *s,
2306		gfp_t gfpflags, int node, unsigned long addr)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2307{
2308	void **object;
2309	struct kmem_cache_cpu *c;
 
2310	unsigned long tid;
2311
2312	if (slab_pre_alloc_hook(s, gfpflags))
2313		return NULL;
2314
2315redo:
2316
2317	/*
2318	 * Must read kmem_cache cpu data via this cpu ptr. Preemption is
2319	 * enabled. We may switch back and forth between cpus while
2320	 * reading from one cpu area. That does not matter as long
2321	 * as we end up on the original cpu again when doing the cmpxchg.
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2322	 */
2323	c = __this_cpu_ptr(s->cpu_slab);
2324
2325	/*
2326	 * The transaction ids are globally unique per cpu and per operation on
2327	 * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
2328	 * occurs on the right processor and that there was no operation on the
2329	 * linked list in between.
2330	 */
2331	tid = c->tid;
2332	barrier();
2333
2334	object = c->freelist;
2335	if (unlikely(!object || !node_match(c, node)))
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2336
2337		object = __slab_alloc(s, gfpflags, node, addr, c);
 
 
 
2338
2339	else {
 
 
 
2340		void *next_object = get_freepointer_safe(s, object);
2341
2342		/*
2343		 * The cmpxchg will only match if there was no additional
2344		 * operation and if we are on the right processor.
2345		 *
2346		 * The cmpxchg does the following atomically (without lock semantics!)
 
2347		 * 1. Relocate first pointer to the current per cpu area.
2348		 * 2. Verify that tid and freelist have not been changed
2349		 * 3. If they were not changed replace tid and freelist
2350		 *
2351		 * Since this is without lock semantics the protection is only against
2352		 * code executing on this cpu *not* from access by other cpus.
 
2353		 */
2354		if (unlikely(!this_cpu_cmpxchg_double(
2355				s->cpu_slab->freelist, s->cpu_slab->tid,
2356				object, tid,
2357				next_object, next_tid(tid)))) {
2358
2359			note_cmpxchg_failure("slab_alloc", s, tid);
2360			goto redo;
2361		}
2362		prefetch_freepointer(s, next_object);
2363		stat(s, ALLOC_FASTPATH);
2364	}
2365
2366	if (unlikely(gfpflags & __GFP_ZERO) && object)
2367		memset(object, 0, s->objsize);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2368
2369	slab_post_alloc_hook(s, gfpflags, object);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2370
2371	return object;
2372}
2373
2374void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
 
 
 
 
 
 
 
 
 
 
 
 
2375{
2376	void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
 
2377
2378	trace_kmem_cache_alloc(_RET_IP_, ret, s->objsize, s->size, gfpflags);
2379
2380	return ret;
2381}
2382EXPORT_SYMBOL(kmem_cache_alloc);
 
 
 
 
 
 
 
 
 
2383
2384#ifdef CONFIG_TRACING
2385void *kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size)
 
 
 
 
 
 
 
 
 
 
 
 
2386{
2387	void *ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, _RET_IP_);
2388	trace_kmalloc(_RET_IP_, ret, size, s->size, gfpflags);
 
 
2389	return ret;
2390}
2391EXPORT_SYMBOL(kmem_cache_alloc_trace);
2392
2393void *kmalloc_order_trace(size_t size, gfp_t flags, unsigned int order)
 
 
 
 
 
2394{
2395	void *ret = kmalloc_order(size, flags, order);
2396	trace_kmalloc(_RET_IP_, ret, size, PAGE_SIZE << order, flags);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2397	return ret;
2398}
2399EXPORT_SYMBOL(kmalloc_order_trace);
2400#endif
2401
2402#ifdef CONFIG_NUMA
2403void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2404{
2405	void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
 
2406
2407	trace_kmem_cache_alloc_node(_RET_IP_, ret,
2408				    s->objsize, s->size, gfpflags, node);
2409
 
2410	return ret;
2411}
2412EXPORT_SYMBOL(kmem_cache_alloc_node);
2413
2414#ifdef CONFIG_TRACING
2415void *kmem_cache_alloc_node_trace(struct kmem_cache *s,
2416				    gfp_t gfpflags,
2417				    int node, size_t size)
2418{
2419	void *ret = slab_alloc(s, gfpflags, node, _RET_IP_);
2420
2421	trace_kmalloc_node(_RET_IP_, ret,
2422			   size, s->size, gfpflags, node);
 
2423	return ret;
2424}
2425EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
2426#endif
2427#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2428
2429/*
2430 * Slow patch handling. This may still be called frequently since objects
2431 * have a longer lifetime than the cpu slabs in most processing loads.
2432 *
2433 * So we still attempt to reduce cache line usage. Just take the slab
2434 * lock and free the item. If there is no additional partial page
2435 * handling required then we can return immediately.
2436 */
2437static void __slab_free(struct kmem_cache *s, struct page *page,
2438			void *x, unsigned long addr)
 
 
2439{
2440	void *prior;
2441	void **object = (void *)x;
2442	int was_frozen;
2443	int inuse;
2444	struct page new;
2445	unsigned long counters;
2446	struct kmem_cache_node *n = NULL;
2447	unsigned long uninitialized_var(flags);
 
2448
2449	stat(s, FREE_SLOWPATH);
2450
2451	if (kmem_cache_debug(s) && !free_debug_processing(s, page, x, addr))
 
2452		return;
 
2453
2454	do {
2455		prior = page->freelist;
2456		counters = page->counters;
2457		set_freepointer(s, object, prior);
 
 
 
 
2458		new.counters = counters;
2459		was_frozen = new.frozen;
2460		new.inuse--;
2461		if ((!new.inuse || !prior) && !was_frozen && !n) {
2462
2463			if (!kmem_cache_debug(s) && !prior)
2464
2465				/*
2466				 * Slab was on no list before and will be partially empty
2467				 * We can defer the list move and instead freeze it.
2468				 */
2469				new.frozen = 1;
2470
2471			else { /* Needs to be taken off a list */
2472
2473	                        n = get_node(s, page_to_nid(page));
2474				/*
2475				 * Speculatively acquire the list_lock.
2476				 * If the cmpxchg does not succeed then we may
2477				 * drop the list_lock without any processing.
2478				 *
2479				 * Otherwise the list_lock will synchronize with
2480				 * other processors updating the list of slabs.
2481				 */
2482				spin_lock_irqsave(&n->list_lock, flags);
2483
 
2484			}
2485		}
2486		inuse = new.inuse;
2487
2488	} while (!cmpxchg_double_slab(s, page,
2489		prior, counters,
2490		object, new.counters,
2491		"__slab_free"));
2492
2493	if (likely(!n)) {
2494
2495		/*
2496		 * If we just froze the page then put it onto the
2497		 * per cpu partial list.
2498		 */
2499		if (new.frozen && !was_frozen) {
2500			put_cpu_partial(s, page, 1);
 
 
 
 
 
 
2501			stat(s, CPU_PARTIAL_FREE);
2502		}
2503		/*
2504		 * The list lock was not taken therefore no list
2505		 * activity can be necessary.
2506		 */
2507                if (was_frozen)
2508                        stat(s, FREE_FROZEN);
2509                return;
2510        }
2511
2512	/*
2513	 * was_frozen may have been set after we acquired the list_lock in
2514	 * an earlier loop. So we need to check it here again.
2515	 */
2516	if (was_frozen)
2517		stat(s, FREE_FROZEN);
2518	else {
2519		if (unlikely(!inuse && n->nr_partial > s->min_partial))
2520                        goto slab_empty;
2521
2522		/*
2523		 * Objects left in the slab. If it was not on the partial list before
2524		 * then add it.
2525		 */
2526		if (unlikely(!prior)) {
2527			remove_full(s, page);
2528			add_partial(n, page, DEACTIVATE_TO_TAIL);
2529			stat(s, FREE_ADD_PARTIAL);
2530		}
 
2531	}
2532	spin_unlock_irqrestore(&n->list_lock, flags);
2533	return;
2534
2535slab_empty:
2536	if (prior) {
2537		/*
2538		 * Slab on the partial list.
2539		 */
2540		remove_partial(n, page);
2541		stat(s, FREE_REMOVE_PARTIAL);
2542	} else
2543		/* Slab must be on the full list */
2544		remove_full(s, page);
2545
2546	spin_unlock_irqrestore(&n->list_lock, flags);
2547	stat(s, FREE_SLAB);
2548	discard_slab(s, page);
2549}
2550
 
2551/*
2552 * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
2553 * can perform fastpath freeing without additional function calls.
2554 *
2555 * The fastpath is only possible if we are freeing to the current cpu slab
2556 * of this processor. This typically the case if we have just allocated
2557 * the item before.
2558 *
2559 * If fastpath is not possible then fall back to __slab_free where we deal
2560 * with all sorts of special processing.
2561 */
2562static __always_inline void slab_free(struct kmem_cache *s,
2563			struct page *page, void *x, unsigned long addr)
 
 
 
 
 
2564{
2565	void **object = (void *)x;
2566	struct kmem_cache_cpu *c;
2567	unsigned long tid;
2568
2569	slab_free_hook(s, x);
2570
2571redo:
2572	/*
2573	 * Determine the currently cpus per cpu slab.
2574	 * The cpu may change afterward. However that does not matter since
2575	 * data is retrieved via this pointer. If we are on the same cpu
2576	 * during the cmpxchg then the free will succedd.
2577	 */
2578	c = __this_cpu_ptr(s->cpu_slab);
 
2579
2580	tid = c->tid;
2581	barrier();
2582
2583	if (likely(page == c->page)) {
2584		set_freepointer(s, object, c->freelist);
 
 
 
 
 
2585
2586		if (unlikely(!this_cpu_cmpxchg_double(
2587				s->cpu_slab->freelist, s->cpu_slab->tid,
2588				c->freelist, tid,
2589				object, next_tid(tid)))) {
2590
 
2591			note_cmpxchg_failure("slab_free", s, tid);
2592			goto redo;
2593		}
2594		stat(s, FREE_FASTPATH);
2595	} else
2596		__slab_free(s, page, x, addr);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2597
 
 
2598}
2599
2600void kmem_cache_free(struct kmem_cache *s, void *x)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2601{
2602	struct page *page;
2603
2604	page = virt_to_head_page(x);
 
 
2605
2606	slab_free(s, page, x, _RET_IP_);
 
 
 
 
 
 
2607
2608	trace_kmem_cache_free(_RET_IP_, x);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2609}
2610EXPORT_SYMBOL(kmem_cache_free);
2611
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2612/*
2613 * Object placement in a slab is made very easy because we always start at
2614 * offset 0. If we tune the size of the object to the alignment then we can
2615 * get the required alignment by putting one properly sized object after
2616 * another.
2617 *
2618 * Notice that the allocation order determines the sizes of the per cpu
2619 * caches. Each processor has always one slab available for allocations.
2620 * Increasing the allocation order reduces the number of times that slabs
2621 * must be moved on and off the partial lists and is therefore a factor in
2622 * locking overhead.
2623 */
2624
2625/*
2626 * Mininum / Maximum order of slab pages. This influences locking overhead
2627 * and slab fragmentation. A higher order reduces the number of partial slabs
2628 * and increases the number of allocations possible without having to
2629 * take the list_lock.
2630 */
2631static int slub_min_order;
2632static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
2633static int slub_min_objects;
2634
2635/*
2636 * Merge control. If this is set then no merging of slab caches will occur.
2637 * (Could be removed. This was introduced to pacify the merge skeptics.)
2638 */
2639static int slub_nomerge;
2640
2641/*
2642 * Calculate the order of allocation given an slab object size.
2643 *
2644 * The order of allocation has significant impact on performance and other
2645 * system components. Generally order 0 allocations should be preferred since
2646 * order 0 does not cause fragmentation in the page allocator. Larger objects
2647 * be problematic to put into order 0 slabs because there may be too much
2648 * unused space left. We go to a higher order if more than 1/16th of the slab
2649 * would be wasted.
2650 *
2651 * In order to reach satisfactory performance we must ensure that a minimum
2652 * number of objects is in one slab. Otherwise we may generate too much
2653 * activity on the partial lists which requires taking the list_lock. This is
2654 * less a concern for large slabs though which are rarely used.
2655 *
2656 * slub_max_order specifies the order where we begin to stop considering the
2657 * number of objects in a slab as critical. If we reach slub_max_order then
2658 * we try to keep the page order as low as possible. So we accept more waste
2659 * of space in favor of a small page order.
2660 *
2661 * Higher order allocations also allow the placement of more objects in a
2662 * slab and thereby reduce object handling overhead. If the user has
2663 * requested a higher mininum order then we start with that one instead of
2664 * the smallest order which will fit the object.
2665 */
2666static inline int slab_order(int size, int min_objects,
2667				int max_order, int fract_leftover, int reserved)
 
2668{
2669	int order;
2670	int rem;
2671	int min_order = slub_min_order;
2672
2673	if (order_objects(min_order, size, reserved) > MAX_OBJS_PER_PAGE)
2674		return get_order(size * MAX_OBJS_PER_PAGE) - 1;
2675
2676	for (order = max(min_order,
2677				fls(min_objects * size - 1) - PAGE_SHIFT);
2678			order <= max_order; order++) {
2679
2680		unsigned long slab_size = PAGE_SIZE << order;
2681
2682		if (slab_size < min_objects * size + reserved)
2683			continue;
2684
2685		rem = (slab_size - reserved) % size;
2686
2687		if (rem <= slab_size / fract_leftover)
2688			break;
2689
2690	}
2691
2692	return order;
2693}
2694
2695static inline int calculate_order(int size, int reserved)
2696{
2697	int order;
2698	int min_objects;
2699	int fraction;
2700	int max_objects;
2701
2702	/*
2703	 * Attempt to find best configuration for a slab. This
2704	 * works by first attempting to generate a layout with
2705	 * the best configuration and backing off gradually.
2706	 *
2707	 * First we reduce the acceptable waste in a slab. Then
2708	 * we reduce the minimum objects required in a slab.
2709	 */
2710	min_objects = slub_min_objects;
2711	if (!min_objects)
2712		min_objects = 4 * (fls(nr_cpu_ids) + 1);
2713	max_objects = order_objects(slub_max_order, size, reserved);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2714	min_objects = min(min_objects, max_objects);
2715
2716	while (min_objects > 1) {
2717		fraction = 16;
2718		while (fraction >= 4) {
2719			order = slab_order(size, min_objects,
2720					slub_max_order, fraction, reserved);
2721			if (order <= slub_max_order)
2722				return order;
2723			fraction /= 2;
2724		}
2725		min_objects--;
2726	}
2727
2728	/*
2729	 * We were unable to place multiple objects in a slab. Now
2730	 * lets see if we can place a single object there.
 
 
 
 
 
 
 
 
 
 
 
2731	 */
2732	order = slab_order(size, 1, slub_max_order, 1, reserved);
2733	if (order <= slub_max_order)
2734		return order;
 
 
 
2735
2736	/*
2737	 * Doh this slab cannot be placed using slub_max_order.
2738	 */
2739	order = slab_order(size, 1, MAX_ORDER, 1, reserved);
2740	if (order < MAX_ORDER)
2741		return order;
2742	return -ENOSYS;
2743}
2744
2745/*
2746 * Figure out what the alignment of the objects will be.
2747 */
2748static unsigned long calculate_alignment(unsigned long flags,
2749		unsigned long align, unsigned long size)
2750{
2751	/*
2752	 * If the user wants hardware cache aligned objects then follow that
2753	 * suggestion if the object is sufficiently large.
2754	 *
2755	 * The hardware cache alignment cannot override the specified
2756	 * alignment though. If that is greater then use it.
2757	 */
2758	if (flags & SLAB_HWCACHE_ALIGN) {
2759		unsigned long ralign = cache_line_size();
2760		while (size <= ralign / 2)
2761			ralign /= 2;
2762		align = max(align, ralign);
2763	}
2764
2765	if (align < ARCH_SLAB_MINALIGN)
2766		align = ARCH_SLAB_MINALIGN;
2767
2768	return ALIGN(align, sizeof(void *));
2769}
2770
2771static void
2772init_kmem_cache_node(struct kmem_cache_node *n)
2773{
2774	n->nr_partial = 0;
2775	spin_lock_init(&n->list_lock);
2776	INIT_LIST_HEAD(&n->partial);
2777#ifdef CONFIG_SLUB_DEBUG
2778	atomic_long_set(&n->nr_slabs, 0);
2779	atomic_long_set(&n->total_objects, 0);
2780	INIT_LIST_HEAD(&n->full);
2781#endif
2782}
2783
 
2784static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
2785{
2786	BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
2787			SLUB_PAGE_SHIFT * sizeof(struct kmem_cache_cpu));
 
2788
2789	/*
2790	 * Must align to double word boundary for the double cmpxchg
2791	 * instructions to work; see __pcpu_double_call_return_bool().
2792	 */
2793	s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
2794				     2 * sizeof(void *));
2795
2796	if (!s->cpu_slab)
2797		return 0;
2798
2799	init_kmem_cache_cpus(s);
2800
2801	return 1;
2802}
 
 
 
 
 
 
2803
2804static struct kmem_cache *kmem_cache_node;
2805
2806/*
2807 * No kmalloc_node yet so do it by hand. We know that this is the first
2808 * slab on the node for this slabcache. There are no concurrent accesses
2809 * possible.
2810 *
2811 * Note that this function only works on the kmalloc_node_cache
2812 * when allocating for the kmalloc_node_cache. This is used for bootstrapping
2813 * memory on a fresh node that has no slab structures yet.
2814 */
2815static void early_kmem_cache_node_alloc(int node)
2816{
2817	struct page *page;
2818	struct kmem_cache_node *n;
2819
2820	BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
2821
2822	page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
2823
2824	BUG_ON(!page);
2825	if (page_to_nid(page) != node) {
2826		printk(KERN_ERR "SLUB: Unable to allocate memory from "
2827				"node %d\n", node);
2828		printk(KERN_ERR "SLUB: Allocating a useless per node structure "
2829				"in order to be able to continue\n");
2830	}
2831
2832	n = page->freelist;
2833	BUG_ON(!n);
2834	page->freelist = get_freepointer(kmem_cache_node, n);
2835	page->inuse = 1;
2836	page->frozen = 0;
2837	kmem_cache_node->node[node] = n;
2838#ifdef CONFIG_SLUB_DEBUG
2839	init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
2840	init_tracking(kmem_cache_node, n);
2841#endif
 
 
 
 
2842	init_kmem_cache_node(n);
2843	inc_slabs_node(kmem_cache_node, node, page->objects);
2844
2845	add_partial(n, page, DEACTIVATE_TO_HEAD);
 
 
 
 
2846}
2847
2848static void free_kmem_cache_nodes(struct kmem_cache *s)
2849{
2850	int node;
 
2851
2852	for_each_node_state(node, N_NORMAL_MEMORY) {
2853		struct kmem_cache_node *n = s->node[node];
2854
2855		if (n)
2856			kmem_cache_free(kmem_cache_node, n);
2857
2858		s->node[node] = NULL;
 
2859	}
2860}
2861
 
 
 
 
 
 
 
 
 
2862static int init_kmem_cache_nodes(struct kmem_cache *s)
2863{
2864	int node;
2865
2866	for_each_node_state(node, N_NORMAL_MEMORY) {
2867		struct kmem_cache_node *n;
2868
2869		if (slab_state == DOWN) {
2870			early_kmem_cache_node_alloc(node);
2871			continue;
2872		}
2873		n = kmem_cache_alloc_node(kmem_cache_node,
2874						GFP_KERNEL, node);
2875
2876		if (!n) {
2877			free_kmem_cache_nodes(s);
2878			return 0;
2879		}
2880
2881		s->node[node] = n;
2882		init_kmem_cache_node(n);
 
2883	}
2884	return 1;
2885}
2886
2887static void set_min_partial(struct kmem_cache *s, unsigned long min)
2888{
2889	if (min < MIN_PARTIAL)
2890		min = MIN_PARTIAL;
2891	else if (min > MAX_PARTIAL)
2892		min = MAX_PARTIAL;
2893	s->min_partial = min;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
2894}
2895
2896/*
2897 * calculate_sizes() determines the order and the distribution of data within
2898 * a slab object.
2899 */
2900static int calculate_sizes(struct kmem_cache *s, int forced_order)
2901{
2902	unsigned long flags = s->flags;
2903	unsigned long size = s->objsize;
2904	unsigned long align = s->align;
2905	int order;
2906
2907	/*
2908	 * Round up object size to the next word boundary. We can only
2909	 * place the free pointer at word boundaries and this determines
2910	 * the possible location of the free pointer.
2911	 */
2912	size = ALIGN(size, sizeof(void *));
2913
2914#ifdef CONFIG_SLUB_DEBUG
2915	/*
2916	 * Determine if we can poison the object itself. If the user of
2917	 * the slab may touch the object after free or before allocation
2918	 * then we should never poison the object itself.
2919	 */
2920	if ((flags & SLAB_POISON) && !(flags & SLAB_DESTROY_BY_RCU) &&
2921			!s->ctor)
2922		s->flags |= __OBJECT_POISON;
2923	else
2924		s->flags &= ~__OBJECT_POISON;
2925
2926
2927	/*
2928	 * If we are Redzoning then check if there is some space between the
2929	 * end of the object and the free pointer. If not then add an
2930	 * additional word to have some bytes to store Redzone information.
2931	 */
2932	if ((flags & SLAB_RED_ZONE) && size == s->objsize)
2933		size += sizeof(void *);
2934#endif
2935
2936	/*
2937	 * With that we have determined the number of bytes in actual use
2938	 * by the object. This is the potential offset to the free pointer.
2939	 */
2940	s->inuse = size;
2941
2942	if (((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
2943		s->ctor)) {
 
 
2944		/*
2945		 * Relocate free pointer after the object if it is not
2946		 * permitted to overwrite the first word of the object on
2947		 * kmem_cache_free.
2948		 *
2949		 * This is the case if we do RCU, have a constructor or
2950		 * destructor or are poisoning the objects.
 
 
 
 
 
 
 
 
2951		 */
2952		s->offset = size;
2953		size += sizeof(void *);
 
 
 
 
 
 
 
 
 
2954	}
2955
2956#ifdef CONFIG_SLUB_DEBUG
2957	if (flags & SLAB_STORE_USER)
2958		/*
2959		 * Need to store information about allocs and frees after
2960		 * the object.
2961		 */
2962		size += 2 * sizeof(struct track);
2963
2964	if (flags & SLAB_RED_ZONE)
 
 
 
 
 
 
 
 
2965		/*
2966		 * Add some empty padding so that we can catch
2967		 * overwrites from earlier objects rather than let
2968		 * tracking information or the free pointer be
2969		 * corrupted if a user writes before the start
2970		 * of the object.
2971		 */
2972		size += sizeof(void *);
2973#endif
2974
2975	/*
2976	 * Determine the alignment based on various parameters that the
2977	 * user specified and the dynamic determination of cache line size
2978	 * on bootup.
2979	 */
2980	align = calculate_alignment(flags, align, s->objsize);
2981	s->align = align;
2982
2983	/*
2984	 * SLUB stores one object immediately after another beginning from
2985	 * offset 0. In order to align the objects we have to simply size
2986	 * each object to conform to the alignment.
2987	 */
2988	size = ALIGN(size, align);
2989	s->size = size;
2990	if (forced_order >= 0)
2991		order = forced_order;
2992	else
2993		order = calculate_order(size, s->reserved);
2994
2995	if (order < 0)
2996		return 0;
2997
2998	s->allocflags = 0;
2999	if (order)
3000		s->allocflags |= __GFP_COMP;
3001
3002	if (s->flags & SLAB_CACHE_DMA)
3003		s->allocflags |= SLUB_DMA;
 
 
 
3004
3005	if (s->flags & SLAB_RECLAIM_ACCOUNT)
3006		s->allocflags |= __GFP_RECLAIMABLE;
3007
3008	/*
3009	 * Determine the number of objects per slab
3010	 */
3011	s->oo = oo_make(order, size, s->reserved);
3012	s->min = oo_make(get_order(size), size, s->reserved);
3013	if (oo_objects(s->oo) > oo_objects(s->max))
3014		s->max = s->oo;
3015
3016	return !!oo_objects(s->oo);
3017
3018}
3019
3020static int kmem_cache_open(struct kmem_cache *s,
3021		const char *name, size_t size,
3022		size_t align, unsigned long flags,
3023		void (*ctor)(void *))
3024{
3025	memset(s, 0, kmem_size);
3026	s->name = name;
3027	s->ctor = ctor;
3028	s->objsize = size;
3029	s->align = align;
3030	s->flags = kmem_cache_flags(size, flags, name, ctor);
3031	s->reserved = 0;
3032
3033	if (need_reserve_slab_rcu && (s->flags & SLAB_DESTROY_BY_RCU))
3034		s->reserved = sizeof(struct rcu_head);
3035
3036	if (!calculate_sizes(s, -1))
3037		goto error;
3038	if (disable_higher_order_debug) {
3039		/*
3040		 * Disable debugging flags that store metadata if the min slab
3041		 * order increased.
3042		 */
3043		if (get_order(s->size) > get_order(s->objsize)) {
3044			s->flags &= ~DEBUG_METADATA_FLAGS;
3045			s->offset = 0;
3046			if (!calculate_sizes(s, -1))
3047				goto error;
3048		}
3049	}
3050
3051#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
3052    defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
3053	if (system_has_cmpxchg_double() && (s->flags & SLAB_DEBUG_FLAGS) == 0)
3054		/* Enable fast mode */
3055		s->flags |= __CMPXCHG_DOUBLE;
3056#endif
3057
3058	/*
3059	 * The larger the object size is, the more pages we want on the partial
3060	 * list to avoid pounding the page allocator excessively.
3061	 */
3062	set_min_partial(s, ilog2(s->size) / 2);
3063
3064	/*
3065	 * cpu_partial determined the maximum number of objects kept in the
3066	 * per cpu partial lists of a processor.
3067	 *
3068	 * Per cpu partial lists mainly contain slabs that just have one
3069	 * object freed. If they are used for allocation then they can be
3070	 * filled up again with minimal effort. The slab will never hit the
3071	 * per node partial lists and therefore no locking will be required.
3072	 *
3073	 * This setting also determines
3074	 *
3075	 * A) The number of objects from per cpu partial slabs dumped to the
3076	 *    per node list when we reach the limit.
3077	 * B) The number of objects in cpu partial slabs to extract from the
3078	 *    per node list when we run out of per cpu objects. We only fetch 50%
3079	 *    to keep some capacity around for frees.
3080	 */
3081	if (kmem_cache_debug(s))
3082		s->cpu_partial = 0;
3083	else if (s->size >= PAGE_SIZE)
3084		s->cpu_partial = 2;
3085	else if (s->size >= 1024)
3086		s->cpu_partial = 6;
3087	else if (s->size >= 256)
3088		s->cpu_partial = 13;
3089	else
3090		s->cpu_partial = 30;
3091
3092	s->refcount = 1;
3093#ifdef CONFIG_NUMA
3094	s->remote_node_defrag_ratio = 1000;
3095#endif
3096	if (!init_kmem_cache_nodes(s))
3097		goto error;
3098
3099	if (alloc_kmem_cache_cpus(s))
3100		return 1;
3101
3102	free_kmem_cache_nodes(s);
3103error:
3104	if (flags & SLAB_PANIC)
3105		panic("Cannot create slab %s size=%lu realsize=%u "
3106			"order=%u offset=%u flags=%lx\n",
3107			s->name, (unsigned long)size, s->size, oo_order(s->oo),
3108			s->offset, flags);
3109	return 0;
3110}
3111
3112/*
3113 * Determine the size of a slab object
3114 */
3115unsigned int kmem_cache_size(struct kmem_cache *s)
3116{
3117	return s->objsize;
3118}
3119EXPORT_SYMBOL(kmem_cache_size);
3120
3121static void list_slab_objects(struct kmem_cache *s, struct page *page,
3122							const char *text)
3123{
3124#ifdef CONFIG_SLUB_DEBUG
3125	void *addr = page_address(page);
3126	void *p;
3127	unsigned long *map = kzalloc(BITS_TO_LONGS(page->objects) *
3128				     sizeof(long), GFP_ATOMIC);
3129	if (!map)
3130		return;
3131	slab_err(s, page, "%s", text);
3132	slab_lock(page);
3133
3134	get_map(s, page, map);
3135	for_each_object(p, s, addr, page->objects) {
 
 
 
 
3136
3137		if (!test_bit(slab_index(p, s, addr), map)) {
3138			printk(KERN_ERR "INFO: Object 0x%p @offset=%tu\n",
3139							p, p - addr);
 
3140			print_tracking(s, p);
3141		}
3142	}
3143	slab_unlock(page);
3144	kfree(map);
3145#endif
3146}
3147
3148/*
3149 * Attempt to free all partial slabs on a node.
3150 * This is called from kmem_cache_close(). We must be the last thread
3151 * using the cache and therefore we do not need to lock anymore.
3152 */
3153static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
3154{
3155	struct page *page, *h;
 
3156
3157	list_for_each_entry_safe(page, h, &n->partial, lru) {
3158		if (!page->inuse) {
3159			remove_partial(n, page);
3160			discard_slab(s, page);
 
 
3161		} else {
3162			list_slab_objects(s, page,
3163				"Objects remaining on kmem_cache_close()");
3164		}
3165	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3166}
3167
3168/*
3169 * Release all resources used by a slab cache.
3170 */
3171static inline int kmem_cache_close(struct kmem_cache *s)
3172{
3173	int node;
 
3174
3175	flush_all(s);
3176	free_percpu(s->cpu_slab);
3177	/* Attempt to free all objects */
3178	for_each_node_state(node, N_NORMAL_MEMORY) {
3179		struct kmem_cache_node *n = get_node(s, node);
3180
3181		free_partial(s, n);
3182		if (n->nr_partial || slabs_node(s, node))
3183			return 1;
3184	}
3185	free_kmem_cache_nodes(s);
3186	return 0;
3187}
3188
3189/*
3190 * Close a cache and release the kmem_cache structure
3191 * (must be used for caches created using kmem_cache_create)
3192 */
3193void kmem_cache_destroy(struct kmem_cache *s)
3194{
3195	down_write(&slub_lock);
3196	s->refcount--;
3197	if (!s->refcount) {
3198		list_del(&s->list);
3199		up_write(&slub_lock);
3200		if (kmem_cache_close(s)) {
3201			printk(KERN_ERR "SLUB %s: %s called for cache that "
3202				"still has objects.\n", s->name, __func__);
3203			dump_stack();
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
3204		}
3205		if (s->flags & SLAB_DESTROY_BY_RCU)
3206			rcu_barrier();
3207		sysfs_slab_remove(s);
3208	} else
3209		up_write(&slub_lock);
3210}
3211EXPORT_SYMBOL(kmem_cache_destroy);
3212
3213/********************************************************************
3214 *		Kmalloc subsystem
3215 *******************************************************************/
3216
3217struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
3218EXPORT_SYMBOL(kmalloc_caches);
3219
3220static struct kmem_cache *kmem_cache;
3221
3222#ifdef CONFIG_ZONE_DMA
3223static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
3224#endif
3225
3226static int __init setup_slub_min_order(char *str)
3227{
3228	get_option(&str, &slub_min_order);
 
 
 
3229
3230	return 1;
3231}
3232
3233__setup("slub_min_order=", setup_slub_min_order);
 
 
3234
3235static int __init setup_slub_max_order(char *str)
3236{
3237	get_option(&str, &slub_max_order);
3238	slub_max_order = min(slub_max_order, MAX_ORDER - 1);
 
 
 
3239
3240	return 1;
3241}
3242
3243__setup("slub_max_order=", setup_slub_max_order);
 
3244
3245static int __init setup_slub_min_objects(char *str)
3246{
3247	get_option(&str, &slub_min_objects);
3248
3249	return 1;
3250}
3251
3252__setup("slub_min_objects=", setup_slub_min_objects);
3253
3254static int __init setup_slub_nomerge(char *str)
3255{
3256	slub_nomerge = 1;
3257	return 1;
3258}
3259
3260__setup("slub_nomerge", setup_slub_nomerge);
3261
3262static struct kmem_cache *__init create_kmalloc_cache(const char *name,
3263						int size, unsigned int flags)
3264{
3265	struct kmem_cache *s;
3266
3267	s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3268
3269	/*
3270	 * This function is called with IRQs disabled during early-boot on
3271	 * single CPU so there's no need to take slub_lock here.
3272	 */
3273	if (!kmem_cache_open(s, name, size, ARCH_KMALLOC_MINALIGN,
3274								flags, NULL))
3275		goto panic;
3276
3277	list_add(&s->list, &slab_caches);
3278	return s;
3279
3280panic:
3281	panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
3282	return NULL;
3283}
3284
3285/*
3286 * Conversion table for small slabs sizes / 8 to the index in the
3287 * kmalloc array. This is necessary for slabs < 192 since we have non power
3288 * of two cache sizes there. The size of larger slabs can be determined using
3289 * fls.
3290 */
3291static s8 size_index[24] = {
3292	3,	/* 8 */
3293	4,	/* 16 */
3294	5,	/* 24 */
3295	5,	/* 32 */
3296	6,	/* 40 */
3297	6,	/* 48 */
3298	6,	/* 56 */
3299	6,	/* 64 */
3300	1,	/* 72 */
3301	1,	/* 80 */
3302	1,	/* 88 */
3303	1,	/* 96 */
3304	7,	/* 104 */
3305	7,	/* 112 */
3306	7,	/* 120 */
3307	7,	/* 128 */
3308	2,	/* 136 */
3309	2,	/* 144 */
3310	2,	/* 152 */
3311	2,	/* 160 */
3312	2,	/* 168 */
3313	2,	/* 176 */
3314	2,	/* 184 */
3315	2	/* 192 */
3316};
3317
3318static inline int size_index_elem(size_t bytes)
3319{
3320	return (bytes - 1) / 8;
3321}
3322
3323static struct kmem_cache *get_slab(size_t size, gfp_t flags)
3324{
3325	int index;
3326
3327	if (size <= 192) {
3328		if (!size)
3329			return ZERO_SIZE_PTR;
3330
3331		index = size_index[size_index_elem(size)];
3332	} else
3333		index = fls(size - 1);
3334
3335#ifdef CONFIG_ZONE_DMA
3336	if (unlikely((flags & SLUB_DMA)))
3337		return kmalloc_dma_caches[index];
3338
3339#endif
3340	return kmalloc_caches[index];
3341}
3342
3343void *__kmalloc(size_t size, gfp_t flags)
3344{
3345	struct kmem_cache *s;
3346	void *ret;
3347
3348	if (unlikely(size > SLUB_MAX_SIZE))
3349		return kmalloc_large(size, flags);
3350
3351	s = get_slab(size, flags);
3352
3353	if (unlikely(ZERO_OR_NULL_PTR(s)))
3354		return s;
3355
3356	ret = slab_alloc(s, flags, NUMA_NO_NODE, _RET_IP_);
3357
3358	trace_kmalloc(_RET_IP_, ret, size, s->size, flags);
3359
3360	return ret;
3361}
3362EXPORT_SYMBOL(__kmalloc);
3363
3364#ifdef CONFIG_NUMA
3365static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
3366{
3367	struct page *page;
3368	void *ptr = NULL;
3369
3370	flags |= __GFP_COMP | __GFP_NOTRACK;
3371	page = alloc_pages_node(node, flags, get_order(size));
3372	if (page)
3373		ptr = page_address(page);
3374
3375	kmemleak_alloc(ptr, size, 1, flags);
3376	return ptr;
3377}
3378
3379void *__kmalloc_node(size_t size, gfp_t flags, int node)
3380{
3381	struct kmem_cache *s;
3382	void *ret;
3383
3384	if (unlikely(size > SLUB_MAX_SIZE)) {
3385		ret = kmalloc_large_node(size, flags, node);
3386
3387		trace_kmalloc_node(_RET_IP_, ret,
3388				   size, PAGE_SIZE << get_order(size),
3389				   flags, node);
3390
3391		return ret;
3392	}
3393
3394	s = get_slab(size, flags);
3395
3396	if (unlikely(ZERO_OR_NULL_PTR(s)))
3397		return s;
3398
3399	ret = slab_alloc(s, flags, node, _RET_IP_);
3400
3401	trace_kmalloc_node(_RET_IP_, ret, size, s->size, flags, node);
3402
3403	return ret;
3404}
3405EXPORT_SYMBOL(__kmalloc_node);
3406#endif
3407
3408size_t ksize(const void *object)
3409{
3410	struct page *page;
3411
3412	if (unlikely(object == ZERO_SIZE_PTR))
3413		return 0;
3414
3415	page = virt_to_head_page(object);
3416
3417	if (unlikely(!PageSlab(page))) {
3418		WARN_ON(!PageCompound(page));
3419		return PAGE_SIZE << compound_order(page);
3420	}
3421
3422	return slab_ksize(page->slab);
3423}
3424EXPORT_SYMBOL(ksize);
3425
3426#ifdef CONFIG_SLUB_DEBUG
3427bool verify_mem_not_deleted(const void *x)
 
 
 
 
 
 
 
 
 
3428{
3429	struct page *page;
3430	void *object = (void *)x;
3431	unsigned long flags;
3432	bool rv;
3433
3434	if (unlikely(ZERO_OR_NULL_PTR(x)))
3435		return false;
3436
3437	local_irq_save(flags);
 
3438
3439	page = virt_to_head_page(x);
3440	if (unlikely(!PageSlab(page))) {
3441		/* maybe it was from stack? */
3442		rv = true;
3443		goto out_unlock;
3444	}
 
 
 
 
3445
3446	slab_lock(page);
3447	if (on_freelist(page->slab, page, object)) {
3448		object_err(page->slab, page, object, "Object is on free-list");
3449		rv = false;
3450	} else {
3451		rv = true;
3452	}
3453	slab_unlock(page);
3454
3455out_unlock:
3456	local_irq_restore(flags);
3457	return rv;
3458}
3459EXPORT_SYMBOL(verify_mem_not_deleted);
3460#endif
3461
3462void kfree(const void *x)
3463{
3464	struct page *page;
3465	void *object = (void *)x;
3466
3467	trace_kfree(_RET_IP_, x);
3468
3469	if (unlikely(ZERO_OR_NULL_PTR(x)))
 
3470		return;
3471
3472	page = virt_to_head_page(x);
3473	if (unlikely(!PageSlab(page))) {
3474		BUG_ON(!PageCompound(page));
3475		kmemleak_free(x);
3476		put_page(page);
3477		return;
3478	}
3479	slab_free(page->slab, page, object, _RET_IP_);
3480}
3481EXPORT_SYMBOL(kfree);
 
 
3482
3483/*
3484 * kmem_cache_shrink removes empty slabs from the partial lists and sorts
3485 * the remaining slabs by the number of items in use. The slabs with the
3486 * most items in use come first. New allocations will then fill those up
3487 * and thus they can be removed from the partial lists.
3488 *
3489 * The slabs with the least items are placed last. This results in them
3490 * being allocated from last increasing the chance that the last objects
3491 * are freed in them.
3492 */
3493int kmem_cache_shrink(struct kmem_cache *s)
3494{
3495	int node;
3496	int i;
3497	struct kmem_cache_node *n;
3498	struct page *page;
3499	struct page *t;
3500	int objects = oo_objects(s->max);
3501	struct list_head *slabs_by_inuse =
3502		kmalloc(sizeof(struct list_head) * objects, GFP_KERNEL);
3503	unsigned long flags;
 
3504
3505	if (!slabs_by_inuse)
3506		return -ENOMEM;
3507
3508	flush_all(s);
3509	for_each_node_state(node, N_NORMAL_MEMORY) {
3510		n = get_node(s, node);
3511
3512		if (!n->nr_partial)
3513			continue;
3514
3515		for (i = 0; i < objects; i++)
3516			INIT_LIST_HEAD(slabs_by_inuse + i);
3517
3518		spin_lock_irqsave(&n->list_lock, flags);
3519
3520		/*
3521		 * Build lists indexed by the items in use in each slab.
3522		 *
3523		 * Note that concurrent frees may occur while we hold the
3524		 * list_lock. page->inuse here is the upper limit.
3525		 */
3526		list_for_each_entry_safe(page, t, &n->partial, lru) {
3527			list_move(&page->lru, slabs_by_inuse + page->inuse);
3528			if (!page->inuse)
 
 
 
 
 
 
 
 
 
3529				n->nr_partial--;
 
 
 
3530		}
3531
3532		/*
3533		 * Rebuild the partial list with the slabs filled up most
3534		 * first and the least used slabs at the end.
3535		 */
3536		for (i = objects - 1; i > 0; i--)
3537			list_splice(slabs_by_inuse + i, n->partial.prev);
3538
3539		spin_unlock_irqrestore(&n->list_lock, flags);
3540
3541		/* Release empty slabs */
3542		list_for_each_entry_safe(page, t, slabs_by_inuse, lru)
3543			discard_slab(s, page);
 
 
 
3544	}
3545
3546	kfree(slabs_by_inuse);
3547	return 0;
 
 
 
 
 
3548}
3549EXPORT_SYMBOL(kmem_cache_shrink);
3550
3551#if defined(CONFIG_MEMORY_HOTPLUG)
3552static int slab_mem_going_offline_callback(void *arg)
3553{
3554	struct kmem_cache *s;
3555
3556	down_read(&slub_lock);
3557	list_for_each_entry(s, &slab_caches, list)
3558		kmem_cache_shrink(s);
3559	up_read(&slub_lock);
 
 
3560
3561	return 0;
3562}
3563
3564static void slab_mem_offline_callback(void *arg)
3565{
3566	struct kmem_cache_node *n;
3567	struct kmem_cache *s;
3568	struct memory_notify *marg = arg;
3569	int offline_node;
3570
3571	offline_node = marg->status_change_nid;
3572
3573	/*
3574	 * If the node still has available memory. we need kmem_cache_node
3575	 * for it yet.
3576	 */
3577	if (offline_node < 0)
3578		return;
3579
3580	down_read(&slub_lock);
3581	list_for_each_entry(s, &slab_caches, list) {
3582		n = get_node(s, offline_node);
3583		if (n) {
3584			/*
3585			 * if n->nr_slabs > 0, slabs still exist on the node
3586			 * that is going down. We were unable to free them,
3587			 * and offline_pages() function shouldn't call this
3588			 * callback. So, we must fail.
3589			 */
3590			BUG_ON(slabs_node(s, offline_node));
3591
3592			s->node[offline_node] = NULL;
3593			kmem_cache_free(kmem_cache_node, n);
3594		}
3595	}
3596	up_read(&slub_lock);
3597}
3598
3599static int slab_mem_going_online_callback(void *arg)
3600{
3601	struct kmem_cache_node *n;
3602	struct kmem_cache *s;
3603	struct memory_notify *marg = arg;
3604	int nid = marg->status_change_nid;
3605	int ret = 0;
3606
3607	/*
3608	 * If the node's memory is already available, then kmem_cache_node is
3609	 * already created. Nothing to do.
3610	 */
3611	if (nid < 0)
3612		return 0;
3613
3614	/*
3615	 * We are bringing a node online. No memory is available yet. We must
3616	 * allocate a kmem_cache_node structure in order to bring the node
3617	 * online.
3618	 */
3619	down_read(&slub_lock);
3620	list_for_each_entry(s, &slab_caches, list) {
3621		/*
 
 
 
 
 
 
3622		 * XXX: kmem_cache_alloc_node will fallback to other nodes
3623		 *      since memory is not yet available from the node that
3624		 *      is brought up.
3625		 */
3626		n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
3627		if (!n) {
3628			ret = -ENOMEM;
3629			goto out;
3630		}
3631		init_kmem_cache_node(n);
3632		s->node[nid] = n;
3633	}
 
 
 
 
 
3634out:
3635	up_read(&slub_lock);
3636	return ret;
3637}
3638
3639static int slab_memory_callback(struct notifier_block *self,
3640				unsigned long action, void *arg)
3641{
3642	int ret = 0;
3643
3644	switch (action) {
3645	case MEM_GOING_ONLINE:
3646		ret = slab_mem_going_online_callback(arg);
3647		break;
3648	case MEM_GOING_OFFLINE:
3649		ret = slab_mem_going_offline_callback(arg);
3650		break;
3651	case MEM_OFFLINE:
3652	case MEM_CANCEL_ONLINE:
3653		slab_mem_offline_callback(arg);
3654		break;
3655	case MEM_ONLINE:
3656	case MEM_CANCEL_OFFLINE:
3657		break;
3658	}
3659	if (ret)
3660		ret = notifier_from_errno(ret);
3661	else
3662		ret = NOTIFY_OK;
3663	return ret;
3664}
3665
3666#endif /* CONFIG_MEMORY_HOTPLUG */
3667
3668/********************************************************************
3669 *			Basic setup of slabs
3670 *******************************************************************/
3671
3672/*
3673 * Used for early kmem_cache structures that were allocated using
3674 * the page allocator
 
3675 */
3676
3677static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
3678{
3679	int node;
 
 
3680
3681	list_add(&s->list, &slab_caches);
3682	s->refcount = -1;
 
 
 
 
 
 
 
 
3683
3684	for_each_node_state(node, N_NORMAL_MEMORY) {
3685		struct kmem_cache_node *n = get_node(s, node);
3686		struct page *p;
3687
3688		if (n) {
3689			list_for_each_entry(p, &n->partial, lru)
3690				p->slab = s;
3691
3692#ifdef CONFIG_SLUB_DEBUG
3693			list_for_each_entry(p, &n->full, lru)
3694				p->slab = s;
3695#endif
3696		}
3697	}
 
 
3698}
3699
3700void __init kmem_cache_init(void)
3701{
3702	int i;
3703	int caches = 0;
3704	struct kmem_cache *temp_kmem_cache;
3705	int order;
3706	struct kmem_cache *temp_kmem_cache_node;
3707	unsigned long kmalloc_size;
3708
3709	if (debug_guardpage_minorder())
3710		slub_max_order = 0;
3711
3712	kmem_size = offsetof(struct kmem_cache, node) +
3713				nr_node_ids * sizeof(struct kmem_cache_node *);
 
3714
3715	/* Allocate two kmem_caches from the page allocator */
3716	kmalloc_size = ALIGN(kmem_size, cache_line_size());
3717	order = get_order(2 * kmalloc_size);
3718	kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
3719
3720	/*
3721	 * Must first have the slab cache available for the allocations of the
3722	 * struct kmem_cache_node's. There is special bootstrap code in
3723	 * kmem_cache_open for slab_state == DOWN.
3724	 */
3725	kmem_cache_node = (void *)kmem_cache + kmalloc_size;
 
3726
3727	kmem_cache_open(kmem_cache_node, "kmem_cache_node",
3728		sizeof(struct kmem_cache_node),
3729		0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3730
3731	hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
3732
3733	/* Able to allocate the per node structures */
3734	slab_state = PARTIAL;
3735
3736	temp_kmem_cache = kmem_cache;
3737	kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
3738		0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
3739	kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3740	memcpy(kmem_cache, temp_kmem_cache, kmem_size);
3741
3742	/*
3743	 * Allocate kmem_cache_node properly from the kmem_cache slab.
3744	 * kmem_cache_node is separately allocated so no need to
3745	 * update any list pointers.
3746	 */
3747	temp_kmem_cache_node = kmem_cache_node;
3748
3749	kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
3750	memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
3751
3752	kmem_cache_bootstrap_fixup(kmem_cache_node);
3753
3754	caches++;
3755	kmem_cache_bootstrap_fixup(kmem_cache);
3756	caches++;
3757	/* Free temporary boot structure */
3758	free_pages((unsigned long)temp_kmem_cache, order);
3759
3760	/* Now we can use the kmem_cache to allocate kmalloc slabs */
 
 
3761
3762	/*
3763	 * Patch up the size_index table if we have strange large alignment
3764	 * requirements for the kmalloc array. This is only the case for
3765	 * MIPS it seems. The standard arches will not generate any code here.
3766	 *
3767	 * Largest permitted alignment is 256 bytes due to the way we
3768	 * handle the index determination for the smaller caches.
3769	 *
3770	 * Make sure that nothing crazy happens if someone starts tinkering
3771	 * around with ARCH_KMALLOC_MINALIGN
3772	 */
3773	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 256 ||
3774		(KMALLOC_MIN_SIZE & (KMALLOC_MIN_SIZE - 1)));
3775
3776	for (i = 8; i < KMALLOC_MIN_SIZE; i += 8) {
3777		int elem = size_index_elem(i);
3778		if (elem >= ARRAY_SIZE(size_index))
3779			break;
3780		size_index[elem] = KMALLOC_SHIFT_LOW;
3781	}
3782
3783	if (KMALLOC_MIN_SIZE == 64) {
3784		/*
3785		 * The 96 byte size cache is not used if the alignment
3786		 * is 64 byte.
3787		 */
3788		for (i = 64 + 8; i <= 96; i += 8)
3789			size_index[size_index_elem(i)] = 7;
3790	} else if (KMALLOC_MIN_SIZE == 128) {
3791		/*
3792		 * The 192 byte sized cache is not used if the alignment
3793		 * is 128 byte. Redirect kmalloc to use the 256 byte cache
3794		 * instead.
3795		 */
3796		for (i = 128 + 8; i <= 192; i += 8)
3797			size_index[size_index_elem(i)] = 8;
3798	}
3799
3800	/* Caches that are not of the two-to-the-power-of size */
3801	if (KMALLOC_MIN_SIZE <= 32) {
3802		kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
3803		caches++;
3804	}
3805
3806	if (KMALLOC_MIN_SIZE <= 64) {
3807		kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
3808		caches++;
3809	}
3810
3811	for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3812		kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
3813		caches++;
3814	}
3815
3816	slab_state = UP;
 
3817
3818	/* Provide the correct kmalloc names now that the caches are up */
3819	if (KMALLOC_MIN_SIZE <= 32) {
3820		kmalloc_caches[1]->name = kstrdup(kmalloc_caches[1]->name, GFP_NOWAIT);
3821		BUG_ON(!kmalloc_caches[1]->name);
3822	}
3823
3824	if (KMALLOC_MIN_SIZE <= 64) {
3825		kmalloc_caches[2]->name = kstrdup(kmalloc_caches[2]->name, GFP_NOWAIT);
3826		BUG_ON(!kmalloc_caches[2]->name);
3827	}
3828
3829	for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
3830		char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
3831
3832		BUG_ON(!s);
3833		kmalloc_caches[i]->name = s;
3834	}
3835
3836#ifdef CONFIG_SMP
3837	register_cpu_notifier(&slab_notifier);
3838#endif
3839
3840#ifdef CONFIG_ZONE_DMA
3841	for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
3842		struct kmem_cache *s = kmalloc_caches[i];
3843
3844		if (s && s->size) {
3845			char *name = kasprintf(GFP_NOWAIT,
3846				 "dma-kmalloc-%d", s->objsize);
3847
3848			BUG_ON(!name);
3849			kmalloc_dma_caches[i] = create_kmalloc_cache(name,
3850				s->objsize, SLAB_CACHE_DMA);
3851		}
3852	}
3853#endif
3854	printk(KERN_INFO
3855		"SLUB: Genslabs=%d, HWalign=%d, Order=%d-%d, MinObjects=%d,"
3856		" CPUs=%d, Nodes=%d\n",
3857		caches, cache_line_size(),
3858		slub_min_order, slub_max_order, slub_min_objects,
3859		nr_cpu_ids, nr_node_ids);
3860}
3861
3862void __init kmem_cache_init_late(void)
3863{
 
 
 
 
3864}
3865
3866/*
3867 * Find a mergeable slab cache
3868 */
3869static int slab_unmergeable(struct kmem_cache *s)
3870{
3871	if (slub_nomerge || (s->flags & SLUB_NEVER_MERGE))
3872		return 1;
3873
3874	if (s->ctor)
3875		return 1;
3876
3877	/*
3878	 * We may have set a slab to be unmergeable during bootstrap.
3879	 */
3880	if (s->refcount < 0)
3881		return 1;
3882
3883	return 0;
3884}
3885
3886static struct kmem_cache *find_mergeable(size_t size,
3887		size_t align, unsigned long flags, const char *name,
3888		void (*ctor)(void *))
3889{
3890	struct kmem_cache *s;
3891
3892	if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
3893		return NULL;
3894
3895	if (ctor)
3896		return NULL;
3897
3898	size = ALIGN(size, sizeof(void *));
3899	align = calculate_alignment(flags, align, size);
3900	size = ALIGN(size, align);
3901	flags = kmem_cache_flags(size, flags, name, NULL);
3902
3903	list_for_each_entry(s, &slab_caches, list) {
3904		if (slab_unmergeable(s))
3905			continue;
3906
3907		if (size > s->size)
3908			continue;
3909
3910		if ((flags & SLUB_MERGE_SAME) != (s->flags & SLUB_MERGE_SAME))
3911				continue;
3912		/*
3913		 * Check if alignment is compatible.
3914		 * Courtesy of Adrian Drzewiecki
3915		 */
3916		if ((s->size & ~(align - 1)) != s->size)
3917			continue;
3918
3919		if (s->size - size >= sizeof(void *))
3920			continue;
3921
3922		return s;
3923	}
3924	return NULL;
3925}
3926
3927struct kmem_cache *kmem_cache_create(const char *name, size_t size,
3928		size_t align, unsigned long flags, void (*ctor)(void *))
3929{
3930	struct kmem_cache *s;
3931	char *n;
3932
3933	if (WARN_ON(!name))
3934		return NULL;
3935
3936	down_write(&slub_lock);
3937	s = find_mergeable(size, align, flags, name, ctor);
3938	if (s) {
 
 
 
 
3939		s->refcount++;
 
3940		/*
3941		 * Adjust the object sizes so that we clear
3942		 * the complete object on kzalloc.
3943		 */
3944		s->objsize = max(s->objsize, (int)size);
3945		s->inuse = max_t(int, s->inuse, ALIGN(size, sizeof(void *)));
3946
3947		if (sysfs_slab_alias(s, name)) {
3948			s->refcount--;
3949			goto err;
3950		}
3951		up_write(&slub_lock);
3952		return s;
3953	}
3954
3955	n = kstrdup(name, GFP_KERNEL);
3956	if (!n)
3957		goto err;
3958
3959	s = kmalloc(kmem_size, GFP_KERNEL);
3960	if (s) {
3961		if (kmem_cache_open(s, n,
3962				size, align, flags, ctor)) {
3963			list_add(&s->list, &slab_caches);
3964			up_write(&slub_lock);
3965			if (sysfs_slab_add(s)) {
3966				down_write(&slub_lock);
3967				list_del(&s->list);
3968				kfree(n);
3969				kfree(s);
3970				goto err;
3971			}
3972			return s;
3973		}
3974		kfree(s);
3975	}
3976	kfree(n);
3977err:
3978	up_write(&slub_lock);
3979
3980	if (flags & SLAB_PANIC)
3981		panic("Cannot create slabcache %s\n", name);
3982	else
3983		s = NULL;
3984	return s;
3985}
3986EXPORT_SYMBOL(kmem_cache_create);
3987
3988#ifdef CONFIG_SMP
3989/*
3990 * Use the cpu notifier to insure that the cpu slabs are flushed when
3991 * necessary.
3992 */
3993static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
3994		unsigned long action, void *hcpu)
3995{
3996	long cpu = (long)hcpu;
3997	struct kmem_cache *s;
3998	unsigned long flags;
3999
4000	switch (action) {
4001	case CPU_UP_CANCELED:
4002	case CPU_UP_CANCELED_FROZEN:
4003	case CPU_DEAD:
4004	case CPU_DEAD_FROZEN:
4005		down_read(&slub_lock);
4006		list_for_each_entry(s, &slab_caches, list) {
4007			local_irq_save(flags);
4008			__flush_cpu_slab(s, cpu);
4009			local_irq_restore(flags);
4010		}
4011		up_read(&slub_lock);
4012		break;
4013	default:
4014		break;
4015	}
4016	return NOTIFY_OK;
4017}
4018
4019static struct notifier_block __cpuinitdata slab_notifier = {
4020	.notifier_call = slab_cpuup_callback
4021};
4022
 
 
 
 
 
 
 
 
 
4023#endif
4024
4025void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, unsigned long caller)
4026{
4027	struct kmem_cache *s;
4028	void *ret;
4029
4030	if (unlikely(size > SLUB_MAX_SIZE))
4031		return kmalloc_large(size, gfpflags);
4032
4033	s = get_slab(size, gfpflags);
4034
4035	if (unlikely(ZERO_OR_NULL_PTR(s)))
4036		return s;
 
 
4037
4038	ret = slab_alloc(s, gfpflags, NUMA_NO_NODE, caller);
 
 
 
 
 
4039
4040	/* Honor the call site pointer we received. */
4041	trace_kmalloc(caller, ret, size, s->size, gfpflags);
 
 
 
 
4042
4043	return ret;
4044}
4045
4046#ifdef CONFIG_NUMA
4047void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
4048					int node, unsigned long caller)
4049{
4050	struct kmem_cache *s;
4051	void *ret;
4052
4053	if (unlikely(size > SLUB_MAX_SIZE)) {
4054		ret = kmalloc_large_node(size, gfpflags, node);
 
 
 
4055
4056		trace_kmalloc_node(caller, ret,
4057				   size, PAGE_SIZE << get_order(size),
4058				   gfpflags, node);
4059
4060		return ret;
4061	}
4062
4063	s = get_slab(size, gfpflags);
4064
4065	if (unlikely(ZERO_OR_NULL_PTR(s)))
4066		return s;
 
4067
4068	ret = slab_alloc(s, gfpflags, node, caller);
 
 
 
 
 
4069
4070	/* Honor the call site pointer we received. */
4071	trace_kmalloc_node(caller, ret, size, s->size, gfpflags, node);
4072
4073	return ret;
 
 
 
4074}
4075#endif
4076
4077#ifdef CONFIG_SYSFS
4078static int count_inuse(struct page *page)
4079{
4080	return page->inuse;
4081}
4082
4083static int count_total(struct page *page)
4084{
4085	return page->objects;
4086}
4087#endif
4088
4089#ifdef CONFIG_SLUB_DEBUG
4090static int validate_slab(struct kmem_cache *s, struct page *page,
4091						unsigned long *map)
4092{
4093	void *p;
4094	void *addr = page_address(page);
4095
4096	if (!check_slab(s, page) ||
4097			!on_freelist(s, page, NULL))
4098		return 0;
4099
4100	/* Now we know that a valid freelist exists */
4101	bitmap_zero(map, page->objects);
 
 
 
4102
4103	get_map(s, page, map);
4104	for_each_object(p, s, addr, page->objects) {
4105		if (test_bit(slab_index(p, s, addr), map))
4106			if (!check_object(s, page, p, SLUB_RED_INACTIVE))
4107				return 0;
4108	}
4109
4110	for_each_object(p, s, addr, page->objects)
4111		if (!test_bit(slab_index(p, s, addr), map))
4112			if (!check_object(s, page, p, SLUB_RED_ACTIVE))
4113				return 0;
4114	return 1;
4115}
4116
4117static void validate_slab_slab(struct kmem_cache *s, struct page *page,
4118						unsigned long *map)
4119{
4120	slab_lock(page);
4121	validate_slab(s, page, map);
4122	slab_unlock(page);
4123}
4124
4125static int validate_slab_node(struct kmem_cache *s,
4126		struct kmem_cache_node *n, unsigned long *map)
4127{
4128	unsigned long count = 0;
4129	struct page *page;
4130	unsigned long flags;
4131
4132	spin_lock_irqsave(&n->list_lock, flags);
4133
4134	list_for_each_entry(page, &n->partial, lru) {
4135		validate_slab_slab(s, page, map);
4136		count++;
4137	}
4138	if (count != n->nr_partial)
4139		printk(KERN_ERR "SLUB %s: %ld partial slabs counted but "
4140			"counter=%ld\n", s->name, count, n->nr_partial);
 
 
4141
4142	if (!(s->flags & SLAB_STORE_USER))
4143		goto out;
4144
4145	list_for_each_entry(page, &n->full, lru) {
4146		validate_slab_slab(s, page, map);
4147		count++;
4148	}
4149	if (count != atomic_long_read(&n->nr_slabs))
4150		printk(KERN_ERR "SLUB: %s %ld slabs counted but "
4151			"counter=%ld\n", s->name, count,
4152			atomic_long_read(&n->nr_slabs));
 
4153
4154out:
4155	spin_unlock_irqrestore(&n->list_lock, flags);
4156	return count;
4157}
4158
4159static long validate_slab_cache(struct kmem_cache *s)
4160{
4161	int node;
4162	unsigned long count = 0;
4163	unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4164				sizeof(unsigned long), GFP_KERNEL);
4165
4166	if (!map)
 
4167		return -ENOMEM;
4168
4169	flush_all(s);
4170	for_each_node_state(node, N_NORMAL_MEMORY) {
4171		struct kmem_cache_node *n = get_node(s, node);
 
 
4172
4173		count += validate_slab_node(s, n, map);
4174	}
4175	kfree(map);
4176	return count;
4177}
 
 
 
4178/*
4179 * Generate lists of code addresses where slabcache objects are allocated
4180 * and freed.
4181 */
4182
4183struct location {
 
4184	unsigned long count;
4185	unsigned long addr;
 
4186	long long sum_time;
4187	long min_time;
4188	long max_time;
4189	long min_pid;
4190	long max_pid;
4191	DECLARE_BITMAP(cpus, NR_CPUS);
4192	nodemask_t nodes;
4193};
4194
4195struct loc_track {
4196	unsigned long max;
4197	unsigned long count;
4198	struct location *loc;
 
4199};
4200
 
 
4201static void free_loc_track(struct loc_track *t)
4202{
4203	if (t->max)
4204		free_pages((unsigned long)t->loc,
4205			get_order(sizeof(struct location) * t->max));
4206}
4207
4208static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
4209{
4210	struct location *l;
4211	int order;
4212
4213	order = get_order(sizeof(struct location) * max);
4214
4215	l = (void *)__get_free_pages(flags, order);
4216	if (!l)
4217		return 0;
4218
4219	if (t->count) {
4220		memcpy(l, t->loc, sizeof(struct location) * t->count);
4221		free_loc_track(t);
4222	}
4223	t->max = max;
4224	t->loc = l;
4225	return 1;
4226}
4227
4228static int add_location(struct loc_track *t, struct kmem_cache *s,
4229				const struct track *track)
 
4230{
4231	long start, end, pos;
4232	struct location *l;
4233	unsigned long caddr;
4234	unsigned long age = jiffies - track->when;
 
 
4235
 
 
 
4236	start = -1;
4237	end = t->count;
4238
4239	for ( ; ; ) {
4240		pos = start + (end - start + 1) / 2;
4241
4242		/*
4243		 * There is nothing at "end". If we end up there
4244		 * we need to add something to before end.
4245		 */
4246		if (pos == end)
4247			break;
4248
4249		caddr = t->loc[pos].addr;
4250		if (track->addr == caddr) {
 
 
 
 
4251
4252			l = &t->loc[pos];
4253			l->count++;
4254			if (track->when) {
4255				l->sum_time += age;
4256				if (age < l->min_time)
4257					l->min_time = age;
4258				if (age > l->max_time)
4259					l->max_time = age;
4260
4261				if (track->pid < l->min_pid)
4262					l->min_pid = track->pid;
4263				if (track->pid > l->max_pid)
4264					l->max_pid = track->pid;
4265
4266				cpumask_set_cpu(track->cpu,
4267						to_cpumask(l->cpus));
4268			}
4269			node_set(page_to_nid(virt_to_page(track)), l->nodes);
4270			return 1;
4271		}
4272
4273		if (track->addr < caddr)
4274			end = pos;
 
 
 
 
 
4275		else
4276			start = pos;
4277	}
4278
4279	/*
4280	 * Not found. Insert new tracking element.
4281	 */
4282	if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
4283		return 0;
4284
4285	l = t->loc + pos;
4286	if (pos < t->count)
4287		memmove(l + 1, l,
4288			(t->count - pos) * sizeof(struct location));
4289	t->count++;
4290	l->count = 1;
4291	l->addr = track->addr;
4292	l->sum_time = age;
4293	l->min_time = age;
4294	l->max_time = age;
4295	l->min_pid = track->pid;
4296	l->max_pid = track->pid;
 
 
4297	cpumask_clear(to_cpumask(l->cpus));
4298	cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
4299	nodes_clear(l->nodes);
4300	node_set(page_to_nid(virt_to_page(track)), l->nodes);
4301	return 1;
4302}
4303
4304static void process_slab(struct loc_track *t, struct kmem_cache *s,
4305		struct page *page, enum track_item alloc,
4306		unsigned long *map)
4307{
4308	void *addr = page_address(page);
 
4309	void *p;
4310
4311	bitmap_zero(map, page->objects);
4312	get_map(s, page, map);
4313
4314	for_each_object(p, s, addr, page->objects)
4315		if (!test_bit(slab_index(p, s, addr), map))
4316			add_location(t, s, get_track(s, p, alloc));
4317}
4318
4319static int list_locations(struct kmem_cache *s, char *buf,
4320					enum track_item alloc)
4321{
4322	int len = 0;
4323	unsigned long i;
4324	struct loc_track t = { 0, 0, NULL };
4325	int node;
4326	unsigned long *map = kmalloc(BITS_TO_LONGS(oo_objects(s->max)) *
4327				     sizeof(unsigned long), GFP_KERNEL);
4328
4329	if (!map || !alloc_loc_track(&t, PAGE_SIZE / sizeof(struct location),
4330				     GFP_TEMPORARY)) {
4331		kfree(map);
4332		return sprintf(buf, "Out of memory\n");
4333	}
4334	/* Push back cpu slabs */
4335	flush_all(s);
4336
4337	for_each_node_state(node, N_NORMAL_MEMORY) {
4338		struct kmem_cache_node *n = get_node(s, node);
4339		unsigned long flags;
4340		struct page *page;
4341
4342		if (!atomic_long_read(&n->nr_slabs))
4343			continue;
4344
4345		spin_lock_irqsave(&n->list_lock, flags);
4346		list_for_each_entry(page, &n->partial, lru)
4347			process_slab(&t, s, page, alloc, map);
4348		list_for_each_entry(page, &n->full, lru)
4349			process_slab(&t, s, page, alloc, map);
4350		spin_unlock_irqrestore(&n->list_lock, flags);
4351	}
4352
4353	for (i = 0; i < t.count; i++) {
4354		struct location *l = &t.loc[i];
4355
4356		if (len > PAGE_SIZE - KSYM_SYMBOL_LEN - 100)
4357			break;
4358		len += sprintf(buf + len, "%7ld ", l->count);
4359
4360		if (l->addr)
4361			len += sprintf(buf + len, "%pS", (void *)l->addr);
4362		else
4363			len += sprintf(buf + len, "<not-available>");
4364
4365		if (l->sum_time != l->min_time) {
4366			len += sprintf(buf + len, " age=%ld/%ld/%ld",
4367				l->min_time,
4368				(long)div_u64(l->sum_time, l->count),
4369				l->max_time);
4370		} else
4371			len += sprintf(buf + len, " age=%ld",
4372				l->min_time);
4373
4374		if (l->min_pid != l->max_pid)
4375			len += sprintf(buf + len, " pid=%ld-%ld",
4376				l->min_pid, l->max_pid);
4377		else
4378			len += sprintf(buf + len, " pid=%ld",
4379				l->min_pid);
4380
4381		if (num_online_cpus() > 1 &&
4382				!cpumask_empty(to_cpumask(l->cpus)) &&
4383				len < PAGE_SIZE - 60) {
4384			len += sprintf(buf + len, " cpus=");
4385			len += cpulist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4386						 to_cpumask(l->cpus));
4387		}
4388
4389		if (nr_online_nodes > 1 && !nodes_empty(l->nodes) &&
4390				len < PAGE_SIZE - 60) {
4391			len += sprintf(buf + len, " nodes=");
4392			len += nodelist_scnprintf(buf + len, PAGE_SIZE - len - 50,
4393					l->nodes);
4394		}
4395
4396		len += sprintf(buf + len, "\n");
4397	}
4398
4399	free_loc_track(&t);
4400	kfree(map);
4401	if (!t.count)
4402		len += sprintf(buf, "No data\n");
4403	return len;
4404}
4405#endif
4406
4407#ifdef SLUB_RESILIENCY_TEST
4408static void resiliency_test(void)
4409{
4410	u8 *p;
4411
4412	BUILD_BUG_ON(KMALLOC_MIN_SIZE > 16 || SLUB_PAGE_SHIFT < 10);
4413
4414	printk(KERN_ERR "SLUB resiliency testing\n");
4415	printk(KERN_ERR "-----------------------\n");
4416	printk(KERN_ERR "A. Corruption after allocation\n");
4417
4418	p = kzalloc(16, GFP_KERNEL);
4419	p[16] = 0x12;
4420	printk(KERN_ERR "\n1. kmalloc-16: Clobber Redzone/next pointer"
4421			" 0x12->0x%p\n\n", p + 16);
4422
4423	validate_slab_cache(kmalloc_caches[4]);
4424
4425	/* Hmmm... The next two are dangerous */
4426	p = kzalloc(32, GFP_KERNEL);
4427	p[32 + sizeof(void *)] = 0x34;
4428	printk(KERN_ERR "\n2. kmalloc-32: Clobber next pointer/next slab"
4429			" 0x34 -> -0x%p\n", p);
4430	printk(KERN_ERR
4431		"If allocated object is overwritten then not detectable\n\n");
4432
4433	validate_slab_cache(kmalloc_caches[5]);
4434	p = kzalloc(64, GFP_KERNEL);
4435	p += 64 + (get_cycles() & 0xff) * sizeof(void *);
4436	*p = 0x56;
4437	printk(KERN_ERR "\n3. kmalloc-64: corrupting random byte 0x56->0x%p\n",
4438									p);
4439	printk(KERN_ERR
4440		"If allocated object is overwritten then not detectable\n\n");
4441	validate_slab_cache(kmalloc_caches[6]);
4442
4443	printk(KERN_ERR "\nB. Corruption after free\n");
4444	p = kzalloc(128, GFP_KERNEL);
4445	kfree(p);
4446	*p = 0x78;
4447	printk(KERN_ERR "1. kmalloc-128: Clobber first word 0x78->0x%p\n\n", p);
4448	validate_slab_cache(kmalloc_caches[7]);
4449
4450	p = kzalloc(256, GFP_KERNEL);
4451	kfree(p);
4452	p[50] = 0x9a;
4453	printk(KERN_ERR "\n2. kmalloc-256: Clobber 50th byte 0x9a->0x%p\n\n",
4454			p);
4455	validate_slab_cache(kmalloc_caches[8]);
4456
4457	p = kzalloc(512, GFP_KERNEL);
4458	kfree(p);
4459	p[512] = 0xab;
4460	printk(KERN_ERR "\n3. kmalloc-512: Clobber redzone 0xab->0x%p\n\n", p);
4461	validate_slab_cache(kmalloc_caches[9]);
4462}
4463#else
4464#ifdef CONFIG_SYSFS
4465static void resiliency_test(void) {};
4466#endif
4467#endif
4468
4469#ifdef CONFIG_SYSFS
4470enum slab_stat_type {
4471	SL_ALL,			/* All slabs */
4472	SL_PARTIAL,		/* Only partially allocated slabs */
4473	SL_CPU,			/* Only slabs used for cpu caches */
4474	SL_OBJECTS,		/* Determine allocated objects not slabs */
4475	SL_TOTAL		/* Determine object capacity not slabs */
4476};
4477
4478#define SO_ALL		(1 << SL_ALL)
4479#define SO_PARTIAL	(1 << SL_PARTIAL)
4480#define SO_CPU		(1 << SL_CPU)
4481#define SO_OBJECTS	(1 << SL_OBJECTS)
4482#define SO_TOTAL	(1 << SL_TOTAL)
4483
4484static ssize_t show_slab_objects(struct kmem_cache *s,
4485			    char *buf, unsigned long flags)
4486{
4487	unsigned long total = 0;
4488	int node;
4489	int x;
4490	unsigned long *nodes;
4491	unsigned long *per_cpu;
4492
4493	nodes = kzalloc(2 * sizeof(unsigned long) * nr_node_ids, GFP_KERNEL);
4494	if (!nodes)
4495		return -ENOMEM;
4496	per_cpu = nodes + nr_node_ids;
4497
4498	if (flags & SO_CPU) {
4499		int cpu;
4500
4501		for_each_possible_cpu(cpu) {
4502			struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
4503			int node = ACCESS_ONCE(c->node);
4504			struct page *page;
 
4505
4506			if (node < 0)
 
4507				continue;
4508			page = ACCESS_ONCE(c->page);
4509			if (page) {
 
 
 
 
 
 
 
 
 
 
 
 
 
 
4510				if (flags & SO_TOTAL)
4511					x = page->objects;
4512				else if (flags & SO_OBJECTS)
4513					x = page->inuse;
4514				else
4515					x = 1;
4516
4517				total += x;
4518				nodes[node] += x;
4519			}
4520			page = c->partial;
4521
4522			if (page) {
4523				x = page->pobjects;
4524				total += x;
4525				nodes[node] += x;
4526			}
4527			per_cpu[node]++;
4528		}
4529	}
4530
4531	lock_memory_hotplug();
 
 
 
 
 
 
 
 
 
 
4532#ifdef CONFIG_SLUB_DEBUG
4533	if (flags & SO_ALL) {
4534		for_each_node_state(node, N_NORMAL_MEMORY) {
4535			struct kmem_cache_node *n = get_node(s, node);
4536
4537		if (flags & SO_TOTAL)
4538			x = atomic_long_read(&n->total_objects);
4539		else if (flags & SO_OBJECTS)
4540			x = atomic_long_read(&n->total_objects) -
4541				count_partial(n, count_free);
4542
 
 
 
 
4543			else
4544				x = atomic_long_read(&n->nr_slabs);
4545			total += x;
4546			nodes[node] += x;
4547		}
4548
4549	} else
4550#endif
4551	if (flags & SO_PARTIAL) {
4552		for_each_node_state(node, N_NORMAL_MEMORY) {
4553			struct kmem_cache_node *n = get_node(s, node);
4554
 
4555			if (flags & SO_TOTAL)
4556				x = count_partial(n, count_total);
4557			else if (flags & SO_OBJECTS)
4558				x = count_partial(n, count_inuse);
4559			else
4560				x = n->nr_partial;
4561			total += x;
4562			nodes[node] += x;
4563		}
4564	}
4565	x = sprintf(buf, "%lu", total);
 
4566#ifdef CONFIG_NUMA
4567	for_each_node_state(node, N_NORMAL_MEMORY)
4568		if (nodes[node])
4569			x += sprintf(buf + x, " N%d=%lu",
4570					node, nodes[node]);
 
4571#endif
4572	unlock_memory_hotplug();
4573	kfree(nodes);
4574	return x + sprintf(buf + x, "\n");
4575}
4576
4577#ifdef CONFIG_SLUB_DEBUG
4578static int any_slab_objects(struct kmem_cache *s)
4579{
4580	int node;
4581
4582	for_each_online_node(node) {
4583		struct kmem_cache_node *n = get_node(s, node);
4584
4585		if (!n)
4586			continue;
4587
4588		if (atomic_long_read(&n->total_objects))
4589			return 1;
4590	}
4591	return 0;
4592}
4593#endif
4594
4595#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
4596#define to_slab(n) container_of(n, struct kmem_cache, kobj)
4597
4598struct slab_attribute {
4599	struct attribute attr;
4600	ssize_t (*show)(struct kmem_cache *s, char *buf);
4601	ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
4602};
4603
4604#define SLAB_ATTR_RO(_name) \
4605	static struct slab_attribute _name##_attr = \
4606	__ATTR(_name, 0400, _name##_show, NULL)
4607
4608#define SLAB_ATTR(_name) \
4609	static struct slab_attribute _name##_attr =  \
4610	__ATTR(_name, 0600, _name##_show, _name##_store)
4611
4612static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
4613{
4614	return sprintf(buf, "%d\n", s->size);
4615}
4616SLAB_ATTR_RO(slab_size);
4617
4618static ssize_t align_show(struct kmem_cache *s, char *buf)
4619{
4620	return sprintf(buf, "%d\n", s->align);
4621}
4622SLAB_ATTR_RO(align);
4623
4624static ssize_t object_size_show(struct kmem_cache *s, char *buf)
4625{
4626	return sprintf(buf, "%d\n", s->objsize);
4627}
4628SLAB_ATTR_RO(object_size);
4629
4630static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
4631{
4632	return sprintf(buf, "%d\n", oo_objects(s->oo));
4633}
4634SLAB_ATTR_RO(objs_per_slab);
4635
4636static ssize_t order_store(struct kmem_cache *s,
4637				const char *buf, size_t length)
4638{
4639	unsigned long order;
4640	int err;
4641
4642	err = strict_strtoul(buf, 10, &order);
4643	if (err)
4644		return err;
4645
4646	if (order > slub_max_order || order < slub_min_order)
4647		return -EINVAL;
4648
4649	calculate_sizes(s, order);
4650	return length;
4651}
4652
4653static ssize_t order_show(struct kmem_cache *s, char *buf)
4654{
4655	return sprintf(buf, "%d\n", oo_order(s->oo));
4656}
4657SLAB_ATTR(order);
4658
4659static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
4660{
4661	return sprintf(buf, "%lu\n", s->min_partial);
4662}
4663
4664static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
4665				 size_t length)
4666{
4667	unsigned long min;
4668	int err;
4669
4670	err = strict_strtoul(buf, 10, &min);
4671	if (err)
4672		return err;
4673
4674	set_min_partial(s, min);
4675	return length;
4676}
4677SLAB_ATTR(min_partial);
4678
4679static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
4680{
4681	return sprintf(buf, "%u\n", s->cpu_partial);
 
 
 
 
 
4682}
4683
4684static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
4685				 size_t length)
4686{
4687	unsigned long objects;
4688	int err;
4689
4690	err = strict_strtoul(buf, 10, &objects);
4691	if (err)
4692		return err;
4693	if (objects && kmem_cache_debug(s))
4694		return -EINVAL;
4695
4696	s->cpu_partial = objects;
4697	flush_all(s);
4698	return length;
4699}
4700SLAB_ATTR(cpu_partial);
4701
4702static ssize_t ctor_show(struct kmem_cache *s, char *buf)
4703{
4704	if (!s->ctor)
4705		return 0;
4706	return sprintf(buf, "%pS\n", s->ctor);
4707}
4708SLAB_ATTR_RO(ctor);
4709
4710static ssize_t aliases_show(struct kmem_cache *s, char *buf)
4711{
4712	return sprintf(buf, "%d\n", s->refcount - 1);
4713}
4714SLAB_ATTR_RO(aliases);
4715
4716static ssize_t partial_show(struct kmem_cache *s, char *buf)
4717{
4718	return show_slab_objects(s, buf, SO_PARTIAL);
4719}
4720SLAB_ATTR_RO(partial);
4721
4722static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
4723{
4724	return show_slab_objects(s, buf, SO_CPU);
4725}
4726SLAB_ATTR_RO(cpu_slabs);
4727
4728static ssize_t objects_show(struct kmem_cache *s, char *buf)
4729{
4730	return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
4731}
4732SLAB_ATTR_RO(objects);
4733
4734static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
4735{
4736	return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
4737}
4738SLAB_ATTR_RO(objects_partial);
4739
4740static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
4741{
4742	int objects = 0;
4743	int pages = 0;
4744	int cpu;
4745	int len;
4746
 
4747	for_each_online_cpu(cpu) {
4748		struct page *page = per_cpu_ptr(s->cpu_slab, cpu)->partial;
4749
4750		if (page) {
4751			pages += page->pages;
4752			objects += page->pobjects;
4753		}
4754	}
 
4755
4756	len = sprintf(buf, "%d(%d)", objects, pages);
 
 
4757
4758#ifdef CONFIG_SMP
4759	for_each_online_cpu(cpu) {
4760		struct page *page = per_cpu_ptr(s->cpu_slab, cpu) ->partial;
4761
4762		if (page && len < PAGE_SIZE - 20)
4763			len += sprintf(buf + len, " C%d=%d(%d)", cpu,
4764				page->pobjects, page->pages);
 
 
 
 
4765	}
4766#endif
4767	return len + sprintf(buf + len, "\n");
 
 
4768}
4769SLAB_ATTR_RO(slabs_cpu_partial);
4770
4771static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
4772{
4773	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
4774}
4775
4776static ssize_t reclaim_account_store(struct kmem_cache *s,
4777				const char *buf, size_t length)
4778{
4779	s->flags &= ~SLAB_RECLAIM_ACCOUNT;
4780	if (buf[0] == '1')
4781		s->flags |= SLAB_RECLAIM_ACCOUNT;
4782	return length;
4783}
4784SLAB_ATTR(reclaim_account);
4785
4786static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
4787{
4788	return sprintf(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
4789}
4790SLAB_ATTR_RO(hwcache_align);
4791
4792#ifdef CONFIG_ZONE_DMA
4793static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
4794{
4795	return sprintf(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
4796}
4797SLAB_ATTR_RO(cache_dma);
4798#endif
4799
4800static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
 
4801{
4802	return sprintf(buf, "%d\n", !!(s->flags & SLAB_DESTROY_BY_RCU));
4803}
4804SLAB_ATTR_RO(destroy_by_rcu);
 
4805
4806static ssize_t reserved_show(struct kmem_cache *s, char *buf)
4807{
4808	return sprintf(buf, "%d\n", s->reserved);
4809}
4810SLAB_ATTR_RO(reserved);
4811
4812#ifdef CONFIG_SLUB_DEBUG
4813static ssize_t slabs_show(struct kmem_cache *s, char *buf)
4814{
4815	return show_slab_objects(s, buf, SO_ALL);
4816}
4817SLAB_ATTR_RO(slabs);
4818
4819static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
4820{
4821	return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
4822}
4823SLAB_ATTR_RO(total_objects);
4824
4825static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
4826{
4827	return sprintf(buf, "%d\n", !!(s->flags & SLAB_DEBUG_FREE));
4828}
 
4829
4830static ssize_t sanity_checks_store(struct kmem_cache *s,
4831				const char *buf, size_t length)
4832{
4833	s->flags &= ~SLAB_DEBUG_FREE;
4834	if (buf[0] == '1') {
4835		s->flags &= ~__CMPXCHG_DOUBLE;
4836		s->flags |= SLAB_DEBUG_FREE;
4837	}
4838	return length;
4839}
4840SLAB_ATTR(sanity_checks);
4841
4842static ssize_t trace_show(struct kmem_cache *s, char *buf)
4843{
4844	return sprintf(buf, "%d\n", !!(s->flags & SLAB_TRACE));
4845}
4846
4847static ssize_t trace_store(struct kmem_cache *s, const char *buf,
4848							size_t length)
4849{
4850	s->flags &= ~SLAB_TRACE;
4851	if (buf[0] == '1') {
4852		s->flags &= ~__CMPXCHG_DOUBLE;
4853		s->flags |= SLAB_TRACE;
4854	}
4855	return length;
4856}
4857SLAB_ATTR(trace);
4858
4859static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
4860{
4861	return sprintf(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
4862}
4863
4864static ssize_t red_zone_store(struct kmem_cache *s,
4865				const char *buf, size_t length)
4866{
4867	if (any_slab_objects(s))
4868		return -EBUSY;
4869
4870	s->flags &= ~SLAB_RED_ZONE;
4871	if (buf[0] == '1') {
4872		s->flags &= ~__CMPXCHG_DOUBLE;
4873		s->flags |= SLAB_RED_ZONE;
4874	}
4875	calculate_sizes(s, -1);
4876	return length;
4877}
4878SLAB_ATTR(red_zone);
4879
4880static ssize_t poison_show(struct kmem_cache *s, char *buf)
4881{
4882	return sprintf(buf, "%d\n", !!(s->flags & SLAB_POISON));
4883}
4884
4885static ssize_t poison_store(struct kmem_cache *s,
4886				const char *buf, size_t length)
4887{
4888	if (any_slab_objects(s))
4889		return -EBUSY;
4890
4891	s->flags &= ~SLAB_POISON;
4892	if (buf[0] == '1') {
4893		s->flags &= ~__CMPXCHG_DOUBLE;
4894		s->flags |= SLAB_POISON;
4895	}
4896	calculate_sizes(s, -1);
4897	return length;
4898}
4899SLAB_ATTR(poison);
4900
4901static ssize_t store_user_show(struct kmem_cache *s, char *buf)
4902{
4903	return sprintf(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
4904}
4905
4906static ssize_t store_user_store(struct kmem_cache *s,
4907				const char *buf, size_t length)
4908{
4909	if (any_slab_objects(s))
4910		return -EBUSY;
4911
4912	s->flags &= ~SLAB_STORE_USER;
4913	if (buf[0] == '1') {
4914		s->flags &= ~__CMPXCHG_DOUBLE;
4915		s->flags |= SLAB_STORE_USER;
4916	}
4917	calculate_sizes(s, -1);
4918	return length;
4919}
4920SLAB_ATTR(store_user);
4921
4922static ssize_t validate_show(struct kmem_cache *s, char *buf)
4923{
4924	return 0;
4925}
4926
4927static ssize_t validate_store(struct kmem_cache *s,
4928			const char *buf, size_t length)
4929{
4930	int ret = -EINVAL;
4931
4932	if (buf[0] == '1') {
4933		ret = validate_slab_cache(s);
4934		if (ret >= 0)
4935			ret = length;
4936	}
4937	return ret;
4938}
4939SLAB_ATTR(validate);
4940
4941static ssize_t alloc_calls_show(struct kmem_cache *s, char *buf)
4942{
4943	if (!(s->flags & SLAB_STORE_USER))
4944		return -ENOSYS;
4945	return list_locations(s, buf, TRACK_ALLOC);
4946}
4947SLAB_ATTR_RO(alloc_calls);
4948
4949static ssize_t free_calls_show(struct kmem_cache *s, char *buf)
4950{
4951	if (!(s->flags & SLAB_STORE_USER))
4952		return -ENOSYS;
4953	return list_locations(s, buf, TRACK_FREE);
4954}
4955SLAB_ATTR_RO(free_calls);
4956#endif /* CONFIG_SLUB_DEBUG */
4957
4958#ifdef CONFIG_FAILSLAB
4959static ssize_t failslab_show(struct kmem_cache *s, char *buf)
4960{
4961	return sprintf(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
4962}
4963
4964static ssize_t failslab_store(struct kmem_cache *s, const char *buf,
4965							size_t length)
4966{
4967	s->flags &= ~SLAB_FAILSLAB;
 
 
4968	if (buf[0] == '1')
4969		s->flags |= SLAB_FAILSLAB;
 
 
 
4970	return length;
4971}
4972SLAB_ATTR(failslab);
4973#endif
4974
4975static ssize_t shrink_show(struct kmem_cache *s, char *buf)
4976{
4977	return 0;
4978}
4979
4980static ssize_t shrink_store(struct kmem_cache *s,
4981			const char *buf, size_t length)
4982{
4983	if (buf[0] == '1') {
4984		int rc = kmem_cache_shrink(s);
4985
4986		if (rc)
4987			return rc;
4988	} else
4989		return -EINVAL;
4990	return length;
4991}
4992SLAB_ATTR(shrink);
4993
4994#ifdef CONFIG_NUMA
4995static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
4996{
4997	return sprintf(buf, "%d\n", s->remote_node_defrag_ratio / 10);
4998}
4999
5000static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
5001				const char *buf, size_t length)
5002{
5003	unsigned long ratio;
5004	int err;
5005
5006	err = strict_strtoul(buf, 10, &ratio);
5007	if (err)
5008		return err;
 
 
5009
5010	if (ratio <= 100)
5011		s->remote_node_defrag_ratio = ratio * 10;
5012
5013	return length;
5014}
5015SLAB_ATTR(remote_node_defrag_ratio);
5016#endif
5017
5018#ifdef CONFIG_SLUB_STATS
5019static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
5020{
5021	unsigned long sum  = 0;
5022	int cpu;
5023	int len;
5024	int *data = kmalloc(nr_cpu_ids * sizeof(int), GFP_KERNEL);
5025
5026	if (!data)
5027		return -ENOMEM;
5028
5029	for_each_online_cpu(cpu) {
5030		unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
5031
5032		data[cpu] = x;
5033		sum += x;
5034	}
5035
5036	len = sprintf(buf, "%lu", sum);
5037
5038#ifdef CONFIG_SMP
5039	for_each_online_cpu(cpu) {
5040		if (data[cpu] && len < PAGE_SIZE - 20)
5041			len += sprintf(buf + len, " C%d=%u", cpu, data[cpu]);
 
5042	}
5043#endif
5044	kfree(data);
5045	return len + sprintf(buf + len, "\n");
 
 
5046}
5047
5048static void clear_stat(struct kmem_cache *s, enum stat_item si)
5049{
5050	int cpu;
5051
5052	for_each_online_cpu(cpu)
5053		per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
5054}
5055
5056#define STAT_ATTR(si, text) 					\
5057static ssize_t text##_show(struct kmem_cache *s, char *buf)	\
5058{								\
5059	return show_stat(s, buf, si);				\
5060}								\
5061static ssize_t text##_store(struct kmem_cache *s,		\
5062				const char *buf, size_t length)	\
5063{								\
5064	if (buf[0] != '0')					\
5065		return -EINVAL;					\
5066	clear_stat(s, si);					\
5067	return length;						\
5068}								\
5069SLAB_ATTR(text);						\
5070
5071STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
5072STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
5073STAT_ATTR(FREE_FASTPATH, free_fastpath);
5074STAT_ATTR(FREE_SLOWPATH, free_slowpath);
5075STAT_ATTR(FREE_FROZEN, free_frozen);
5076STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
5077STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
5078STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
5079STAT_ATTR(ALLOC_SLAB, alloc_slab);
5080STAT_ATTR(ALLOC_REFILL, alloc_refill);
5081STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
5082STAT_ATTR(FREE_SLAB, free_slab);
5083STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
5084STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
5085STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
5086STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
5087STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
5088STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
5089STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
5090STAT_ATTR(ORDER_FALLBACK, order_fallback);
5091STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
5092STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
5093STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
5094STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
5095STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
5096STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5097#endif
5098
5099static struct attribute *slab_attrs[] = {
5100	&slab_size_attr.attr,
5101	&object_size_attr.attr,
5102	&objs_per_slab_attr.attr,
5103	&order_attr.attr,
5104	&min_partial_attr.attr,
5105	&cpu_partial_attr.attr,
5106	&objects_attr.attr,
5107	&objects_partial_attr.attr,
5108	&partial_attr.attr,
5109	&cpu_slabs_attr.attr,
5110	&ctor_attr.attr,
5111	&aliases_attr.attr,
5112	&align_attr.attr,
5113	&hwcache_align_attr.attr,
5114	&reclaim_account_attr.attr,
5115	&destroy_by_rcu_attr.attr,
5116	&shrink_attr.attr,
5117	&reserved_attr.attr,
5118	&slabs_cpu_partial_attr.attr,
5119#ifdef CONFIG_SLUB_DEBUG
5120	&total_objects_attr.attr,
 
5121	&slabs_attr.attr,
5122	&sanity_checks_attr.attr,
5123	&trace_attr.attr,
5124	&red_zone_attr.attr,
5125	&poison_attr.attr,
5126	&store_user_attr.attr,
5127	&validate_attr.attr,
5128	&alloc_calls_attr.attr,
5129	&free_calls_attr.attr,
5130#endif
5131#ifdef CONFIG_ZONE_DMA
5132	&cache_dma_attr.attr,
5133#endif
5134#ifdef CONFIG_NUMA
5135	&remote_node_defrag_ratio_attr.attr,
5136#endif
5137#ifdef CONFIG_SLUB_STATS
5138	&alloc_fastpath_attr.attr,
5139	&alloc_slowpath_attr.attr,
5140	&free_fastpath_attr.attr,
5141	&free_slowpath_attr.attr,
5142	&free_frozen_attr.attr,
5143	&free_add_partial_attr.attr,
5144	&free_remove_partial_attr.attr,
5145	&alloc_from_partial_attr.attr,
5146	&alloc_slab_attr.attr,
5147	&alloc_refill_attr.attr,
5148	&alloc_node_mismatch_attr.attr,
5149	&free_slab_attr.attr,
5150	&cpuslab_flush_attr.attr,
5151	&deactivate_full_attr.attr,
5152	&deactivate_empty_attr.attr,
5153	&deactivate_to_head_attr.attr,
5154	&deactivate_to_tail_attr.attr,
5155	&deactivate_remote_frees_attr.attr,
5156	&deactivate_bypass_attr.attr,
5157	&order_fallback_attr.attr,
5158	&cmpxchg_double_fail_attr.attr,
5159	&cmpxchg_double_cpu_fail_attr.attr,
5160	&cpu_partial_alloc_attr.attr,
5161	&cpu_partial_free_attr.attr,
5162	&cpu_partial_node_attr.attr,
5163	&cpu_partial_drain_attr.attr,
5164#endif
5165#ifdef CONFIG_FAILSLAB
5166	&failslab_attr.attr,
5167#endif
 
 
 
 
 
 
5168
5169	NULL
5170};
5171
5172static struct attribute_group slab_attr_group = {
5173	.attrs = slab_attrs,
5174};
5175
5176static ssize_t slab_attr_show(struct kobject *kobj,
5177				struct attribute *attr,
5178				char *buf)
5179{
5180	struct slab_attribute *attribute;
5181	struct kmem_cache *s;
5182	int err;
5183
5184	attribute = to_slab_attr(attr);
5185	s = to_slab(kobj);
5186
5187	if (!attribute->show)
5188		return -EIO;
5189
5190	err = attribute->show(s, buf);
5191
5192	return err;
5193}
5194
5195static ssize_t slab_attr_store(struct kobject *kobj,
5196				struct attribute *attr,
5197				const char *buf, size_t len)
5198{
5199	struct slab_attribute *attribute;
5200	struct kmem_cache *s;
5201	int err;
5202
5203	attribute = to_slab_attr(attr);
5204	s = to_slab(kobj);
5205
5206	if (!attribute->store)
5207		return -EIO;
5208
5209	err = attribute->store(s, buf, len);
5210
5211	return err;
5212}
5213
5214static void kmem_cache_release(struct kobject *kobj)
5215{
5216	struct kmem_cache *s = to_slab(kobj);
5217
5218	kfree(s->name);
5219	kfree(s);
5220}
5221
5222static const struct sysfs_ops slab_sysfs_ops = {
5223	.show = slab_attr_show,
5224	.store = slab_attr_store,
5225};
5226
5227static struct kobj_type slab_ktype = {
5228	.sysfs_ops = &slab_sysfs_ops,
5229	.release = kmem_cache_release
5230};
5231
5232static int uevent_filter(struct kset *kset, struct kobject *kobj)
5233{
5234	struct kobj_type *ktype = get_ktype(kobj);
5235
5236	if (ktype == &slab_ktype)
5237		return 1;
5238	return 0;
5239}
5240
5241static const struct kset_uevent_ops slab_uevent_ops = {
5242	.filter = uevent_filter,
5243};
5244
5245static struct kset *slab_kset;
5246
5247#define ID_STR_LENGTH 64
5248
5249/* Create a unique string id for a slab cache:
5250 *
5251 * Format	:[flags-]size
5252 */
5253static char *create_unique_id(struct kmem_cache *s)
5254{
5255	char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
5256	char *p = name;
5257
5258	BUG_ON(!name);
 
5259
5260	*p++ = ':';
5261	/*
5262	 * First flags affecting slabcache operations. We will only
5263	 * get here for aliasable slabs so we do not need to support
5264	 * too many flags. The flags here must cover all flags that
5265	 * are matched during merging to guarantee that the id is
5266	 * unique.
5267	 */
5268	if (s->flags & SLAB_CACHE_DMA)
5269		*p++ = 'd';
 
 
5270	if (s->flags & SLAB_RECLAIM_ACCOUNT)
5271		*p++ = 'a';
5272	if (s->flags & SLAB_DEBUG_FREE)
5273		*p++ = 'F';
5274	if (!(s->flags & SLAB_NOTRACK))
5275		*p++ = 't';
5276	if (p != name + 1)
5277		*p++ = '-';
5278	p += sprintf(p, "%07d", s->size);
5279	BUG_ON(p > name + ID_STR_LENGTH - 1);
 
 
 
 
 
5280	return name;
5281}
5282
5283static int sysfs_slab_add(struct kmem_cache *s)
5284{
5285	int err;
5286	const char *name;
5287	int unmergeable;
 
5288
5289	if (slab_state < SYSFS)
5290		/* Defer until later */
5291		return 0;
5292
5293	unmergeable = slab_unmergeable(s);
5294	if (unmergeable) {
5295		/*
5296		 * Slabcache can never be merged so we can use the name proper.
5297		 * This is typically the case for debug situations. In that
5298		 * case we can catch duplicate names easily.
5299		 */
5300		sysfs_remove_link(&slab_kset->kobj, s->name);
5301		name = s->name;
5302	} else {
5303		/*
5304		 * Create a unique name for the slab as a target
5305		 * for the symlinks.
5306		 */
5307		name = create_unique_id(s);
 
 
5308	}
5309
5310	s->kobj.kset = slab_kset;
5311	err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, name);
5312	if (err) {
5313		kobject_put(&s->kobj);
5314		return err;
5315	}
5316
5317	err = sysfs_create_group(&s->kobj, &slab_attr_group);
5318	if (err) {
5319		kobject_del(&s->kobj);
5320		kobject_put(&s->kobj);
5321		return err;
5322	}
5323	kobject_uevent(&s->kobj, KOBJ_ADD);
5324	if (!unmergeable) {
5325		/* Setup first alias */
5326		sysfs_slab_alias(s, s->name);
5327		kfree(name);
5328	}
5329	return 0;
 
 
 
 
 
 
5330}
5331
5332static void sysfs_slab_remove(struct kmem_cache *s)
5333{
5334	if (slab_state < SYSFS)
5335		/*
5336		 * Sysfs has not been setup yet so no need to remove the
5337		 * cache from sysfs.
5338		 */
5339		return;
5340
5341	kobject_uevent(&s->kobj, KOBJ_REMOVE);
5342	kobject_del(&s->kobj);
5343	kobject_put(&s->kobj);
5344}
5345
5346/*
5347 * Need to buffer aliases during bootup until sysfs becomes
5348 * available lest we lose that information.
5349 */
5350struct saved_alias {
5351	struct kmem_cache *s;
5352	const char *name;
5353	struct saved_alias *next;
5354};
5355
5356static struct saved_alias *alias_list;
5357
5358static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
5359{
5360	struct saved_alias *al;
5361
5362	if (slab_state == SYSFS) {
5363		/*
5364		 * If we have a leftover link then remove it.
5365		 */
5366		sysfs_remove_link(&slab_kset->kobj, name);
 
 
 
 
 
5367		return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
5368	}
5369
5370	al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
5371	if (!al)
5372		return -ENOMEM;
5373
5374	al->s = s;
5375	al->name = name;
5376	al->next = alias_list;
5377	alias_list = al;
 
5378	return 0;
5379}
5380
5381static int __init slab_sysfs_init(void)
5382{
5383	struct kmem_cache *s;
5384	int err;
5385
5386	down_write(&slub_lock);
5387
5388	slab_kset = kset_create_and_add("slab", &slab_uevent_ops, kernel_kobj);
5389	if (!slab_kset) {
5390		up_write(&slub_lock);
5391		printk(KERN_ERR "Cannot register slab subsystem.\n");
5392		return -ENOSYS;
5393	}
5394
5395	slab_state = SYSFS;
5396
5397	list_for_each_entry(s, &slab_caches, list) {
5398		err = sysfs_slab_add(s);
5399		if (err)
5400			printk(KERN_ERR "SLUB: Unable to add boot slab %s"
5401						" to sysfs\n", s->name);
5402	}
5403
5404	while (alias_list) {
5405		struct saved_alias *al = alias_list;
5406
5407		alias_list = alias_list->next;
5408		err = sysfs_slab_alias(al->s, al->name);
5409		if (err)
5410			printk(KERN_ERR "SLUB: Unable to add boot slab alias"
5411					" %s to sysfs\n", s->name);
5412		kfree(al);
5413	}
5414
5415	up_write(&slub_lock);
5416	resiliency_test();
5417	return 0;
5418}
 
 
5419
5420__initcall(slab_sysfs_init);
5421#endif /* CONFIG_SYSFS */
 
 
 
 
5422
5423/*
5424 * The /proc/slabinfo ABI
5425 */
5426#ifdef CONFIG_SLABINFO
5427static void print_slabinfo_header(struct seq_file *m)
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
5428{
5429	seq_puts(m, "slabinfo - version: 2.1\n");
5430	seq_puts(m, "# name            <active_objs> <num_objs> <objsize> "
5431		 "<objperslab> <pagesperslab>");
5432	seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>");
5433	seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>");
5434	seq_putc(m, '\n');
5435}
5436
5437static void *s_start(struct seq_file *m, loff_t *pos)
5438{
5439	loff_t n = *pos;
5440
5441	down_read(&slub_lock);
5442	if (!n)
5443		print_slabinfo_header(m);
5444
5445	return seq_list_start(&slab_caches, *pos);
5446}
5447
5448static void *s_next(struct seq_file *m, void *p, loff_t *pos)
5449{
5450	return seq_list_next(p, &slab_caches, pos);
 
 
 
 
 
 
5451}
5452
5453static void s_stop(struct seq_file *m, void *p)
5454{
5455	up_read(&slub_lock);
 
 
 
5456}
5457
5458static int s_show(struct seq_file *m, void *p)
 
 
 
 
 
 
 
5459{
5460	unsigned long nr_partials = 0;
5461	unsigned long nr_slabs = 0;
5462	unsigned long nr_inuse = 0;
5463	unsigned long nr_objs = 0;
5464	unsigned long nr_free = 0;
5465	struct kmem_cache *s;
5466	int node;
 
 
 
 
5467
5468	s = list_entry(p, struct kmem_cache, list);
 
5469
5470	for_each_online_node(node) {
5471		struct kmem_cache_node *n = get_node(s, node);
 
 
 
 
 
 
 
 
5472
5473		if (!n)
 
 
 
 
 
 
 
 
 
 
5474			continue;
5475
5476		nr_partials += n->nr_partial;
5477		nr_slabs += atomic_long_read(&n->nr_slabs);
5478		nr_objs += atomic_long_read(&n->total_objects);
5479		nr_free += count_partial(n, count_free);
 
 
5480	}
5481
5482	nr_inuse = nr_objs - nr_free;
5483
5484	seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", s->name, nr_inuse,
5485		   nr_objs, s->size, oo_objects(s->oo),
5486		   (1 << oo_order(s->oo)));
5487	seq_printf(m, " : tunables %4u %4u %4u", 0, 0, 0);
5488	seq_printf(m, " : slabdata %6lu %6lu %6lu", nr_slabs, nr_slabs,
5489		   0UL);
5490	seq_putc(m, '\n');
5491	return 0;
5492}
5493
5494static const struct seq_operations slabinfo_op = {
5495	.start = s_start,
5496	.next = s_next,
5497	.stop = s_stop,
5498	.show = s_show,
 
 
 
 
 
 
 
 
 
5499};
5500
5501static int slabinfo_open(struct inode *inode, struct file *file)
5502{
5503	return seq_open(file, &slabinfo_op);
 
 
 
 
 
 
 
 
 
 
 
5504}
5505
5506static const struct file_operations proc_slabinfo_operations = {
5507	.open		= slabinfo_open,
5508	.read		= seq_read,
5509	.llseek		= seq_lseek,
5510	.release	= seq_release,
5511};
5512
5513static int __init slab_proc_init(void)
5514{
5515	proc_create("slabinfo", S_IRUSR, NULL, &proc_slabinfo_operations);
 
 
 
 
 
 
 
5516	return 0;
 
5517}
5518module_init(slab_proc_init);
5519#endif /* CONFIG_SLABINFO */