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Diffstat (limited to 'mm/slab.c')
| -rw-r--r-- | mm/slab.c | 3060 |
1 files changed, 3060 insertions, 0 deletions
diff --git a/mm/slab.c b/mm/slab.c new file mode 100644 index 0000000..ec660d8 --- /dev/null +++ b/mm/slab.c @@ -0,0 +1,3060 @@ +/* + * linux/mm/slab.c + * Written by Mark Hemment, 1996/97. + * (markhe@nextd.demon.co.uk) + * + * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli + * + * Major cleanup, different bufctl logic, per-cpu arrays + * (c) 2000 Manfred Spraul + * + * Cleanup, make the head arrays unconditional, preparation for NUMA + * (c) 2002 Manfred Spraul + * + * An implementation of the Slab Allocator as described in outline in; + * UNIX Internals: The New Frontiers by Uresh Vahalia + * Pub: Prentice Hall ISBN 0-13-101908-2 + * or with a little more detail in; + * The Slab Allocator: An Object-Caching Kernel Memory Allocator + * Jeff Bonwick (Sun Microsystems). + * Presented at: USENIX Summer 1994 Technical Conference + * + * The memory is organized in caches, one cache for each object type. + * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct) + * Each cache consists out of many slabs (they are small (usually one + * page long) and always contiguous), and each slab contains multiple + * initialized objects. + * + * This means, that your constructor is used only for newly allocated + * slabs and you must pass objects with the same intializations to + * kmem_cache_free. + * + * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM, + * normal). If you need a special memory type, then must create a new + * cache for that memory type. + * + * In order to reduce fragmentation, the slabs are sorted in 3 groups: + * full slabs with 0 free objects + * partial slabs + * empty slabs with no allocated objects + * + * If partial slabs exist, then new allocations come from these slabs, + * otherwise from empty slabs or new slabs are allocated. + * + * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache + * during kmem_cache_destroy(). The caller must prevent concurrent allocs. + * + * Each cache has a short per-cpu head array, most allocs + * and frees go into that array, and if that array overflows, then 1/2 + * of the entries in the array are given back into the global cache. + * The head array is strictly LIFO and should improve the cache hit rates. + * On SMP, it additionally reduces the spinlock operations. + * + * The c_cpuarray may not be read with enabled local interrupts - + * it's changed with a smp_call_function(). + * + * SMP synchronization: + * constructors and destructors are called without any locking. + * Several members in kmem_cache_t and struct slab never change, they + * are accessed without any locking. + * The per-cpu arrays are never accessed from the wrong cpu, no locking, + * and local interrupts are disabled so slab code is preempt-safe. + * The non-constant members are protected with a per-cache irq spinlock. + * + * Many thanks to Mark Hemment, who wrote another per-cpu slab patch + * in 2000 - many ideas in the current implementation are derived from + * his patch. + * + * Further notes from the original documentation: + * + * 11 April '97. Started multi-threading - markhe + * The global cache-chain is protected by the semaphore 'cache_chain_sem'. + * The sem is only needed when accessing/extending the cache-chain, which + * can never happen inside an interrupt (kmem_cache_create(), + * kmem_cache_shrink() and kmem_cache_reap()). + * + * At present, each engine can be growing a cache. This should be blocked. + * + */ + +#include <linux/config.h> +#include <linux/slab.h> +#include <linux/mm.h> +#include <linux/swap.h> +#include <linux/cache.h> +#include <linux/interrupt.h> +#include <linux/init.h> +#include <linux/compiler.h> +#include <linux/seq_file.h> +#include <linux/notifier.h> +#include <linux/kallsyms.h> +#include <linux/cpu.h> +#include <linux/sysctl.h> +#include <linux/module.h> +#include <linux/rcupdate.h> + +#include <asm/uaccess.h> +#include <asm/cacheflush.h> +#include <asm/tlbflush.h> +#include <asm/page.h> + +/* + * DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL, + * SLAB_RED_ZONE & SLAB_POISON. + * 0 for faster, smaller code (especially in the critical paths). + * + * STATS - 1 to collect stats for /proc/slabinfo. + * 0 for faster, smaller code (especially in the critical paths). + * + * FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible) + */ + +#ifdef CONFIG_DEBUG_SLAB +#define DEBUG 1 +#define STATS 1 +#define FORCED_DEBUG 1 +#else +#define DEBUG 0 +#define STATS 0 +#define FORCED_DEBUG 0 +#endif + + +/* Shouldn't this be in a header file somewhere? */ +#define BYTES_PER_WORD sizeof(void *) + +#ifndef cache_line_size +#define cache_line_size() L1_CACHE_BYTES +#endif + +#ifndef ARCH_KMALLOC_MINALIGN +/* + * Enforce a minimum alignment for the kmalloc caches. + * Usually, the kmalloc caches are cache_line_size() aligned, except when + * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned. + * Some archs want to perform DMA into kmalloc caches and need a guaranteed + * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that. + * Note that this flag disables some debug features. + */ +#define ARCH_KMALLOC_MINALIGN 0 +#endif + +#ifndef ARCH_SLAB_MINALIGN +/* + * Enforce a minimum alignment for all caches. + * Intended for archs that get misalignment faults even for BYTES_PER_WORD + * aligned buffers. Includes ARCH_KMALLOC_MINALIGN. + * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables + * some debug features. + */ +#define ARCH_SLAB_MINALIGN 0 +#endif + +#ifndef ARCH_KMALLOC_FLAGS +#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN +#endif + +/* Legal flag mask for kmem_cache_create(). */ +#if DEBUG +# define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \ + SLAB_POISON | SLAB_HWCACHE_ALIGN | \ + SLAB_NO_REAP | SLAB_CACHE_DMA | \ + SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \ + SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ + SLAB_DESTROY_BY_RCU) +#else +# define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \ + SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \ + SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \ + SLAB_DESTROY_BY_RCU) +#endif + +/* + * kmem_bufctl_t: + * + * Bufctl's are used for linking objs within a slab + * linked offsets. + * + * This implementation relies on "struct page" for locating the cache & + * slab an object belongs to. + * This allows the bufctl structure to be small (one int), but limits + * the number of objects a slab (not a cache) can contain when off-slab + * bufctls are used. The limit is the size of the largest general cache + * that does not use off-slab slabs. + * For 32bit archs with 4 kB pages, is this 56. + * This is not serious, as it is only for large objects, when it is unwise + * to have too many per slab. + * Note: This limit can be raised by introducing a general cache whose size + * is less than 512 (PAGE_SIZE<<3), but greater than 256. + */ + +#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0) +#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1) +#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-2) + +/* Max number of objs-per-slab for caches which use off-slab slabs. + * Needed to avoid a possible looping condition in cache_grow(). + */ +static unsigned long offslab_limit; + +/* + * struct slab + * + * Manages the objs in a slab. Placed either at the beginning of mem allocated + * for a slab, or allocated from an general cache. + * Slabs are chained into three list: fully used, partial, fully free slabs. + */ +struct slab { + struct list_head list; + unsigned long colouroff; + void *s_mem; /* including colour offset */ + unsigned int inuse; /* num of objs active in slab */ + kmem_bufctl_t free; +}; + +/* + * struct slab_rcu + * + * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to + * arrange for kmem_freepages to be called via RCU. This is useful if + * we need to approach a kernel structure obliquely, from its address + * obtained without the usual locking. We can lock the structure to + * stabilize it and check it's still at the given address, only if we + * can be sure that the memory has not been meanwhile reused for some + * other kind of object (which our subsystem's lock might corrupt). + * + * rcu_read_lock before reading the address, then rcu_read_unlock after + * taking the spinlock within the structure expected at that address. + * + * We assume struct slab_rcu can overlay struct slab when destroying. + */ +struct slab_rcu { + struct rcu_head head; + kmem_cache_t *cachep; + void *addr; +}; + +/* + * struct array_cache + * + * Per cpu structures + * Purpose: + * - LIFO ordering, to hand out cache-warm objects from _alloc + * - reduce the number of linked list operations + * - reduce spinlock operations + * + * The limit is stored in the per-cpu structure to reduce the data cache + * footprint. + * + */ +struct array_cache { + unsigned int avail; + unsigned int limit; + unsigned int batchcount; + unsigned int touched; +}; + +/* bootstrap: The caches do not work without cpuarrays anymore, + * but the cpuarrays are allocated from the generic caches... + */ +#define BOOT_CPUCACHE_ENTRIES 1 +struct arraycache_init { + struct array_cache cache; + void * entries[BOOT_CPUCACHE_ENTRIES]; +}; + +/* + * The slab lists of all objects. + * Hopefully reduce the internal fragmentation + * NUMA: The spinlock could be moved from the kmem_cache_t + * into this structure, too. Figure out what causes + * fewer cross-node spinlock operations. + */ +struct kmem_list3 { + struct list_head slabs_partial; /* partial list first, better asm code */ + struct list_head slabs_full; + struct list_head slabs_free; + unsigned long free_objects; + int free_touched; + unsigned long next_reap; + struct array_cache *shared; +}; + +#define LIST3_INIT(parent) \ + { \ + .slabs_full = LIST_HEAD_INIT(parent.slabs_full), \ + .slabs_partial = LIST_HEAD_INIT(parent.slabs_partial), \ + .slabs_free = LIST_HEAD_INIT(parent.slabs_free) \ + } +#define list3_data(cachep) \ + (&(cachep)->lists) + +/* NUMA: per-node */ +#define list3_data_ptr(cachep, ptr) \ + list3_data(cachep) + +/* + * kmem_cache_t + * + * manages a cache. + */ + +struct kmem_cache_s { +/* 1) per-cpu data, touched during every alloc/free */ + struct array_cache *array[NR_CPUS]; + unsigned int batchcount; + unsigned int limit; +/* 2) touched by every alloc & free from the backend */ + struct kmem_list3 lists; + /* NUMA: kmem_3list_t *nodelists[MAX_NUMNODES] */ + unsigned int objsize; + unsigned int flags; /* constant flags */ + unsigned int num; /* # of objs per slab */ + unsigned int free_limit; /* upper limit of objects in the lists */ + spinlock_t spinlock; + +/* 3) cache_grow/shrink */ + /* order of pgs per slab (2^n) */ + unsigned int gfporder; + + /* force GFP flags, e.g. GFP_DMA */ + unsigned int gfpflags; + + size_t colour; /* cache colouring range */ + unsigned int colour_off; /* colour offset */ + unsigned int colour_next; /* cache colouring */ + kmem_cache_t *slabp_cache; + unsigned int slab_size; + unsigned int dflags; /* dynamic flags */ + + /* constructor func */ + void (*ctor)(void *, kmem_cache_t *, unsigned long); + + /* de-constructor func */ + void (*dtor)(void *, kmem_cache_t *, unsigned long); + +/* 4) cache creation/removal */ + const char *name; + struct list_head next; + +/* 5) statistics */ +#if STATS + unsigned long num_active; + unsigned long num_allocations; + unsigned long high_mark; + unsigned long grown; + unsigned long reaped; + unsigned long errors; + unsigned long max_freeable; + unsigned long node_allocs; + atomic_t allochit; + atomic_t allocmiss; + atomic_t freehit; + atomic_t freemiss; +#endif +#if DEBUG + int dbghead; + int reallen; +#endif +}; + +#define CFLGS_OFF_SLAB (0x80000000UL) +#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB) + +#define BATCHREFILL_LIMIT 16 +/* Optimization question: fewer reaps means less + * probability for unnessary cpucache drain/refill cycles. + * + * OTHO the cpuarrays can contain lots of objects, + * which could lock up otherwise freeable slabs. + */ +#define REAPTIMEOUT_CPUC (2*HZ) +#define REAPTIMEOUT_LIST3 (4*HZ) + +#if STATS +#define STATS_INC_ACTIVE(x) ((x)->num_active++) +#define STATS_DEC_ACTIVE(x) ((x)->num_active--) +#define STATS_INC_ALLOCED(x) ((x)->num_allocations++) +#define STATS_INC_GROWN(x) ((x)->grown++) +#define STATS_INC_REAPED(x) ((x)->reaped++) +#define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \ + (x)->high_mark = (x)->num_active; \ + } while (0) +#define STATS_INC_ERR(x) ((x)->errors++) +#define STATS_INC_NODEALLOCS(x) ((x)->node_allocs++) +#define STATS_SET_FREEABLE(x, i) \ + do { if ((x)->max_freeable < i) \ + (x)->max_freeable = i; \ + } while (0) + +#define STATS_INC_ALLOCHIT(x) atomic_inc(&(x)->allochit) +#define STATS_INC_ALLOCMISS(x) atomic_inc(&(x)->allocmiss) +#define STATS_INC_FREEHIT(x) atomic_inc(&(x)->freehit) +#define STATS_INC_FREEMISS(x) atomic_inc(&(x)->freemiss) +#else +#define STATS_INC_ACTIVE(x) do { } while (0) +#define STATS_DEC_ACTIVE(x) do { } while (0) +#define STATS_INC_ALLOCED(x) do { } while (0) +#define STATS_INC_GROWN(x) do { } while (0) +#define STATS_INC_REAPED(x) do { } while (0) +#define STATS_SET_HIGH(x) do { } while (0) +#define STATS_INC_ERR(x) do { } while (0) +#define STATS_INC_NODEALLOCS(x) do { } while (0) +#define STATS_SET_FREEABLE(x, i) \ + do { } while (0) + +#define STATS_INC_ALLOCHIT(x) do { } while (0) +#define STATS_INC_ALLOCMISS(x) do { } while (0) +#define STATS_INC_FREEHIT(x) do { } while (0) +#define STATS_INC_FREEMISS(x) do { } while (0) +#endif + +#if DEBUG +/* Magic nums for obj red zoning. + * Placed in the first word before and the first word after an obj. + */ +#define RED_INACTIVE 0x5A2CF071UL /* when obj is inactive */ +#define RED_ACTIVE 0x170FC2A5UL /* when obj is active */ + +/* ...and for poisoning */ +#define POISON_INUSE 0x5a /* for use-uninitialised poisoning */ +#define POISON_FREE 0x6b /* for use-after-free poisoning */ +#define POISON_END 0xa5 /* end-byte of poisoning */ + +/* memory layout of objects: + * 0 : objp + * 0 .. cachep->dbghead - BYTES_PER_WORD - 1: padding. This ensures that + * the end of an object is aligned with the end of the real + * allocation. Catches writes behind the end of the allocation. + * cachep->dbghead - BYTES_PER_WORD .. cachep->dbghead - 1: + * redzone word. + * cachep->dbghead: The real object. + * cachep->objsize - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long] + * cachep->objsize - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long] + */ +static int obj_dbghead(kmem_cache_t *cachep) +{ + return cachep->dbghead; +} + +static int obj_reallen(kmem_cache_t *cachep) +{ + return cachep->reallen; +} + +static unsigned long *dbg_redzone1(kmem_cache_t *cachep, void *objp) +{ + BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); + return (unsigned long*) (objp+obj_dbghead(cachep)-BYTES_PER_WORD); +} + +static unsigned long *dbg_redzone2(kmem_cache_t *cachep, void *objp) +{ + BUG_ON(!(cachep->flags & SLAB_RED_ZONE)); + if (cachep->flags & SLAB_STORE_USER) + return (unsigned long*) (objp+cachep->objsize-2*BYTES_PER_WORD); + return (unsigned long*) (objp+cachep->objsize-BYTES_PER_WORD); +} + +static void **dbg_userword(kmem_cache_t *cachep, void *objp) +{ + BUG_ON(!(cachep->flags & SLAB_STORE_USER)); + return (void**)(objp+cachep->objsize-BYTES_PER_WORD); +} + +#else + +#define obj_dbghead(x) 0 +#define obj_reallen(cachep) (cachep->objsize) +#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long *)NULL;}) +#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long *)NULL;}) +#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;}) + +#endif + +/* + * Maximum size of an obj (in 2^order pages) + * and absolute limit for the gfp order. + */ +#if defined(CONFIG_LARGE_ALLOCS) +#define MAX_OBJ_ORDER 13 /* up to 32Mb */ +#define MAX_GFP_ORDER 13 /* up to 32Mb */ +#elif defined(CONFIG_MMU) +#define MAX_OBJ_ORDER 5 /* 32 pages */ +#define MAX_GFP_ORDER 5 /* 32 pages */ +#else +#define MAX_OBJ_ORDER 8 /* up to 1Mb */ +#define MAX_GFP_ORDER 8 /* up to 1Mb */ +#endif + +/* + * Do not go above this order unless 0 objects fit into the slab. + */ +#define BREAK_GFP_ORDER_HI 1 +#define BREAK_GFP_ORDER_LO 0 +static int slab_break_gfp_order = BREAK_GFP_ORDER_LO; + +/* Macros for storing/retrieving the cachep and or slab from the + * global 'mem_map'. These are used to find the slab an obj belongs to. + * With kfree(), these are used to find the cache which an obj belongs to. + */ +#define SET_PAGE_CACHE(pg,x) ((pg)->lru.next = (struct list_head *)(x)) +#define GET_PAGE_CACHE(pg) ((kmem_cache_t *)(pg)->lru.next) +#define SET_PAGE_SLAB(pg,x) ((pg)->lru.prev = (struct list_head *)(x)) +#define GET_PAGE_SLAB(pg) ((struct slab *)(pg)->lru.prev) + +/* These are the default caches for kmalloc. Custom caches can have other sizes. */ +struct cache_sizes malloc_sizes[] = { +#define CACHE(x) { .cs_size = (x) }, +#include <linux/kmalloc_sizes.h> + CACHE(ULONG_MAX) +#undef CACHE +}; +EXPORT_SYMBOL(malloc_sizes); + +/* Must match cache_sizes above. Out of line to keep cache footprint low. */ +struct cache_names { + char *name; + char *name_dma; +}; + +static struct cache_names __initdata cache_names[] = { +#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" }, +#include <linux/kmalloc_sizes.h> + { NULL, } +#undef CACHE +}; + +static struct arraycache_init initarray_cache __initdata = + { { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; +static struct arraycache_init initarray_generic = + { { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} }; + +/* internal cache of cache description objs */ +static kmem_cache_t cache_cache = { + .lists = LIST3_INIT(cache_cache.lists), + .batchcount = 1, + .limit = BOOT_CPUCACHE_ENTRIES, + .objsize = sizeof(kmem_cache_t), + .flags = SLAB_NO_REAP, + .spinlock = SPIN_LOCK_UNLOCKED, + .name = "kmem_cache", +#if DEBUG + .reallen = sizeof(kmem_cache_t), +#endif +}; + +/* Guard access to the cache-chain. */ +static struct semaphore cache_chain_sem; +static struct list_head cache_chain; + +/* + * vm_enough_memory() looks at this to determine how many + * slab-allocated pages are possibly freeable under pressure + * + * SLAB_RECLAIM_ACCOUNT turns this on per-slab + */ +atomic_t slab_reclaim_pages; +EXPORT_SYMBOL(slab_reclaim_pages); + +/* + * chicken and egg problem: delay the per-cpu array allocation + * until the general caches are up. + */ +static enum { + NONE, + PARTIAL, + FULL +} g_cpucache_up; + +static DEFINE_PER_CPU(struct work_struct, reap_work); + +static void free_block(kmem_cache_t* cachep, void** objpp, int len); +static void enable_cpucache (kmem_cache_t *cachep); +static void cache_reap (void *unused); + +static inline void **ac_entry(struct array_cache *ac) +{ + return (void**)(ac+1); +} + +static inline struct array_cache *ac_data(kmem_cache_t *cachep) +{ + return cachep->array[smp_processor_id()]; +} + +static inline kmem_cache_t *kmem_find_general_cachep(size_t size, int gfpflags) +{ + struct cache_sizes *csizep = malloc_sizes; + +#if DEBUG + /* This happens if someone tries to call + * kmem_cache_create(), or __kmalloc(), before + * the generic caches are initialized. + */ + BUG_ON(csizep->cs_cachep == NULL); +#endif + while (size > csizep->cs_size) + csizep++; + + /* + * Really subtile: The last entry with cs->cs_size==ULONG_MAX + * has cs_{dma,}cachep==NULL. Thus no special case + * for large kmalloc calls required. + */ + if (unlikely(gfpflags & GFP_DMA)) + return csizep->cs_dmacachep; + return csizep->cs_cachep; +} + +/* Cal the num objs, wastage, and bytes left over for a given slab size. */ +static void cache_estimate(unsigned long gfporder, size_t size, size_t align, + int flags, size_t *left_over, unsigned int *num) +{ + int i; + size_t wastage = PAGE_SIZE<<gfporder; + size_t extra = 0; + size_t base = 0; + + if (!(flags & CFLGS_OFF_SLAB)) { + base = sizeof(struct slab); + extra = sizeof(kmem_bufctl_t); + } + i = 0; + while (i*size + ALIGN(base+i*extra, align) <= wastage) + i++; + if (i > 0) + i--; + + if (i > SLAB_LIMIT) + i = SLAB_LIMIT; + + *num = i; + wastage -= i*size; + wastage -= ALIGN(base+i*extra, align); + *left_over = wastage; +} + +#define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg) + +static void __slab_error(const char *function, kmem_cache_t *cachep, char *msg) +{ + printk(KERN_ERR "slab error in %s(): cache `%s': %s\n", + function, cachep->name, msg); + dump_stack(); +} + +/* + * Initiate the reap timer running on the target CPU. We run at around 1 to 2Hz + * via the workqueue/eventd. + * Add the CPU number into the expiration time to minimize the possibility of + * the CPUs getting into lockstep and contending for the global cache chain + * lock. + */ +static void __devinit start_cpu_timer(int cpu) +{ + struct work_struct *reap_work = &per_cpu(reap_work, cpu); + + /* + * When this gets called from do_initcalls via cpucache_init(), + * init_workqueues() has already run, so keventd will be setup + * at that time. + */ + if (keventd_up() && reap_work->func == NULL) { + INIT_WORK(reap_work, cache_reap, NULL); + schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu); + } +} + +static struct array_cache *alloc_arraycache(int cpu, int entries, + int batchcount) +{ + int memsize = sizeof(void*)*entries+sizeof(struct array_cache); + struct array_cache *nc = NULL; + + if (cpu != -1) { + kmem_cache_t *cachep; + cachep = kmem_find_general_cachep(memsize, GFP_KERNEL); + if (cachep) + nc = kmem_cache_alloc_node(cachep, cpu_to_node(cpu)); + } + if (!nc) + nc = kmalloc(memsize, GFP_KERNEL); + if (nc) { + nc->avail = 0; + nc->limit = entries; + nc->batchcount = batchcount; + nc->touched = 0; + } + return nc; +} + +static int __devinit cpuup_callback(struct notifier_block *nfb, + unsigned long action, void *hcpu) +{ + long cpu = (long)hcpu; + kmem_cache_t* cachep; + + switch (action) { + case CPU_UP_PREPARE: + down(&cache_chain_sem); + list_for_each_entry(cachep, &cache_chain, next) { + struct array_cache *nc; + + nc = alloc_arraycache(cpu, cachep->limit, cachep->batchcount); + if (!nc) + goto bad; + + spin_lock_irq(&cachep->spinlock); + cachep->array[cpu] = nc; + cachep->free_limit = (1+num_online_cpus())*cachep->batchcount + + cachep->num; + spin_unlock_irq(&cachep->spinlock); + + } + up(&cache_chain_sem); + break; + case CPU_ONLINE: + start_cpu_timer(cpu); + break; +#ifdef CONFIG_HOTPLUG_CPU + case CPU_DEAD: + /* fall thru */ + case CPU_UP_CANCELED: + down(&cache_chain_sem); + + list_for_each_entry(cachep, &cache_chain, next) { + struct array_cache *nc; + + spin_lock_irq(&cachep->spinlock); + /* cpu is dead; no one can alloc from it. */ + nc = cachep->array[cpu]; + cachep->array[cpu] = NULL; + cachep->free_limit -= cachep->batchcount; + free_block(cachep, ac_entry(nc), nc->avail); + spin_unlock_irq(&cachep->spinlock); + kfree(nc); + } + up(&cache_chain_sem); + break; +#endif + } + return NOTIFY_OK; +bad: + up(&cache_chain_sem); + return NOTIFY_BAD; +} + +static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 }; + +/* Initialisation. + * Called after the gfp() functions have been enabled, and before smp_init(). + */ +void __init kmem_cache_init(void) +{ + size_t left_over; + struct cache_sizes *sizes; + struct cache_names *names; + + /* + * Fragmentation resistance on low memory - only use bigger + * page orders on machines with more than 32MB of memory. + */ + if (num_physpages > (32 << 20) >> PAGE_SHIFT) + slab_break_gfp_order = BREAK_GFP_ORDER_HI; + + + /* Bootstrap is tricky, because several objects are allocated + * from caches that do not exist yet: + * 1) initialize the cache_cache cache: it contains the kmem_cache_t + * structures of all caches, except cache_cache itself: cache_cache + * is statically allocated. + * Initially an __init data area is used for the head array, it's + * replaced with a kmalloc allocated array at the end of the bootstrap. + * 2) Create the first kmalloc cache. + * The kmem_cache_t for the new cache is allocated normally. An __init + * data area is used for the head array. + * 3) Create the remaining kmalloc caches, with minimally sized head arrays. + * 4) Replace the __init data head arrays for cache_cache and the first + * kmalloc cache with kmalloc allocated arrays. + * 5) Resize the head arrays of the kmalloc caches to their final sizes. + */ + + /* 1) create the cache_cache */ + init_MUTEX(&cache_chain_sem); + INIT_LIST_HEAD(&cache_chain); + list_add(&cache_cache.next, &cache_chain); + cache_cache.colour_off = cache_line_size(); + cache_cache.array[smp_processor_id()] = &initarray_cache.cache; + + cache_cache.objsize = ALIGN(cache_cache.objsize, cache_line_size()); + + cache_estimate(0, cache_cache.objsize, cache_line_size(), 0, + &left_over, &cache_cache.num); + if (!cache_cache.num) + BUG(); + + cache_cache.colour = left_over/cache_cache.colour_off; + cache_cache.colour_next = 0; + cache_cache.slab_size = ALIGN(cache_cache.num*sizeof(kmem_bufctl_t) + + sizeof(struct slab), cache_line_size()); + + /* 2+3) create the kmalloc caches */ + sizes = malloc_sizes; + names = cache_names; + + while (sizes->cs_size != ULONG_MAX) { + /* For performance, all the general caches are L1 aligned. + * This should be particularly beneficial on SMP boxes, as it + * eliminates "false sharing". + * Note for systems short on memory removing the alignment will + * allow tighter packing of the smaller caches. */ + sizes->cs_cachep = kmem_cache_create(names->name, + sizes->cs_size, ARCH_KMALLOC_MINALIGN, + (ARCH_KMALLOC_FLAGS | SLAB_PANIC), NULL, NULL); + + /* Inc off-slab bufctl limit until the ceiling is hit. */ + if (!(OFF_SLAB(sizes->cs_cachep))) { + offslab_limit = sizes->cs_size-sizeof(struct slab); + offslab_limit /= sizeof(kmem_bufctl_t); + } + + sizes->cs_dmacachep = kmem_cache_create(names->name_dma, + sizes->cs_size, ARCH_KMALLOC_MINALIGN, + (ARCH_KMALLOC_FLAGS | SLAB_CACHE_DMA | SLAB_PANIC), + NULL, NULL); + + sizes++; + names++; + } + /* 4) Replace the bootstrap head arrays */ + { + void * ptr; + + ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL); + local_irq_disable(); + BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache); + memcpy(ptr, ac_data(&cache_cache), sizeof(struct arraycache_init)); + cache_cache.array[smp_processor_id()] = ptr; + local_irq_enable(); + + ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL); + local_irq_disable(); + BUG_ON(ac_data(malloc_sizes[0].cs_cachep) != &initarray_generic.cache); + memcpy(ptr, ac_data(malloc_sizes[0].cs_cachep), + sizeof(struct arraycache_init)); + malloc_sizes[0].cs_cachep->array[smp_processor_id()] = ptr; + local_irq_enable(); + } + + /* 5) resize the head arrays to their final sizes */ + { + kmem_cache_t *cachep; + down(&cache_chain_sem); + list_for_each_entry(cachep, &cache_chain, next) + enable_cpucache(cachep); + up(&cache_chain_sem); + } + + /* Done! */ + g_cpucache_up = FULL; + + /* Register a cpu startup notifier callback + * that initializes ac_data for all new cpus + */ + register_cpu_notifier(&cpucache_notifier); + + + /* The reap timers are started later, with a module init call: + * That part of the kernel is not yet operational. + */ +} + +static int __init cpucache_init(void) +{ + int cpu; + + /* + * Register the timers that return unneeded + * pages to gfp. + */ + for (cpu = 0; cpu < NR_CPUS; cpu++) { + if (cpu_online(cpu)) + start_cpu_timer(cpu); + } + + return 0; +} + +__initcall(cpucache_init); + +/* + * Interface to system's page allocator. No need to hold the cache-lock. + * + * If we requested dmaable memory, we will get it. Even if we + * did not request dmaable memory, we might get it, but that + * would be relatively rare and ignorable. + */ +static void *kmem_getpages(kmem_cache_t *cachep, unsigned int __nocast flags, int nodeid) +{ + struct page *page; + void *addr; + int i; + + flags |= cachep->gfpflags; + if (likely(nodeid == -1)) { + page = alloc_pages(flags, cachep->gfporder); + } else { + page = alloc_pages_node(nodeid, flags, cachep->gfporder); + } + if (!page) + return NULL; + addr = page_address(page); + + i = (1 << cachep->gfporder); + if (cachep->flags & SLAB_RECLAIM_ACCOUNT) + atomic_add(i, &slab_reclaim_pages); + add_page_state(nr_slab, i); + while (i--) { + SetPageSlab(page); + page++; + } + return addr; +} + +/* + * Interface to system's page release. + */ +static void kmem_freepages(kmem_cache_t *cachep, void *addr) +{ + unsigned long i = (1<<cachep->gfporder); + struct page *page = virt_to_page(addr); + const unsigned long nr_freed = i; + + while (i--) { + if (!TestClearPageSlab(page)) + BUG(); + page++; + } + sub_page_state(nr_slab, nr_freed); + if (current->reclaim_state) + current->reclaim_state->reclaimed_slab += nr_freed; + free_pages((unsigned long)addr, cachep->gfporder); + if (cachep->flags & SLAB_RECLAIM_ACCOUNT) + atomic_sub(1<<cachep->gfporder, &slab_reclaim_pages); +} + +static void kmem_rcu_free(struct rcu_head *head) +{ + struct slab_rcu *slab_rcu = (struct slab_rcu *) head; + kmem_cache_t *cachep = slab_rcu->cachep; + + kmem_freepages(cachep, slab_rcu->addr); + if (OFF_SLAB(cachep)) + kmem_cache_free(cachep->slabp_cache, slab_rcu); +} + +#if DEBUG + +#ifdef CONFIG_DEBUG_PAGEALLOC +static void store_stackinfo(kmem_cache_t *cachep, unsigned long *addr, + unsigned long caller) +{ + int size = obj_reallen(cachep); + + addr = (unsigned long *)&((char*)addr)[obj_dbghead(cachep)]; + + if (size < 5*sizeof(unsigned long)) + return; + + *addr++=0x12345678; + *addr++=caller; + *addr++=smp_processor_id(); + size -= 3*sizeof(unsigned long); + { + unsigned long *sptr = &caller; + unsigned long svalue; + + while (!kstack_end(sptr)) { + svalue = *sptr++; + if (kernel_text_address(svalue)) { + *addr++=svalue; + size -= sizeof(unsigned long); + if (size <= sizeof(unsigned long)) + break; + } + } + + } + *addr++=0x87654321; +} +#endif + +static void poison_obj(kmem_cache_t *cachep, void *addr, unsigned char val) +{ + int size = obj_reallen(cachep); + addr = &((char*)addr)[obj_dbghead(cachep)]; + + memset(addr, val, size); + *(unsigned char *)(addr+size-1) = POISON_END; +} + +static void dump_line(char *data, int offset, int limit) +{ + int i; + printk(KERN_ERR "%03x:", offset); + for (i=0;i<limit;i++) { + printk(" %02x", (unsigned char)data[offset+i]); + } + printk("\n"); +} +#endif + +#if DEBUG + +static void print_objinfo(kmem_cache_t *cachep, void *objp, int lines) +{ + int i, size; + char *realobj; + + if (cachep->flags & SLAB_RED_ZONE) { + printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n", + *dbg_redzone1(cachep, objp), + *dbg_redzone2(cachep, objp)); + } + + if (cachep->flags & SLAB_STORE_USER) { + printk(KERN_ERR "Last user: [<%p>]", + *dbg_userword(cachep, objp)); + print_symbol("(%s)", + (unsigned long)*dbg_userword(cachep, objp)); + printk("\n"); + } + realobj = (char*)objp+obj_dbghead(cachep); + size = obj_reallen(cachep); + for (i=0; i<size && lines;i+=16, lines--) { + int limit; + limit = 16; + if (i+limit > size) + limit = size-i; + dump_line(realobj, i, limit); + } +} + +static void check_poison_obj(kmem_cache_t *cachep, void *objp) +{ + char *realobj; + int size, i; + int lines = 0; + + realobj = (char*)objp+obj_dbghead(cachep); + size = obj_reallen(cachep); + + for (i=0;i<size;i++) { + char exp = POISON_FREE; + if (i == size-1) + exp = POISON_END; + if (realobj[i] != exp) { + int limit; + /* Mismatch ! */ + /* Print header */ + if (lines == 0) { + printk(KERN_ERR "Slab corruption: start=%p, len=%d\n", + realobj, size); + print_objinfo(cachep, objp, 0); + } + /* Hexdump the affected line */ + i = (i/16)*16; + limit = 16; + if (i+limit > size) + limit = size-i; + dump_line(realobj, i, limit); + i += 16; + lines++; + /* Limit to 5 lines */ + if (lines > 5) + break; + } + } + if (lines != 0) { + /* Print some data about the neighboring objects, if they + * exist: + */ + struct slab *slabp = GET_PAGE_SLAB(virt_to_page(objp)); + int objnr; + + objnr = (objp-slabp->s_mem)/cachep->objsize; + if (objnr) { + objp = slabp->s_mem+(objnr-1)*cachep->objsize; + realobj = (char*)objp+obj_dbghead(cachep); + printk(KERN_ERR "Prev obj: start=%p, len=%d\n", + realobj, size); + print_objinfo(cachep, objp, 2); + } + if (objnr+1 < cachep->num) { + objp = slabp->s_mem+(objnr+1)*cachep->objsize; + realobj = (char*)objp+obj_dbghead(cachep); + printk(KERN_ERR "Next obj: start=%p, len=%d\n", + realobj, size); + print_objinfo(cachep, objp, 2); + } + } +} +#endif + +/* Destroy all the objs in a slab, and release the mem back to the system. + * Before calling the slab must have been unlinked from the cache. + * The cache-lock is not held/needed. + */ +static void slab_destroy (kmem_cache_t *cachep, struct slab *slabp) +{ + void *addr = slabp->s_mem - slabp->colouroff; + +#if DEBUG + int i; + for (i = 0; i < cachep->num; i++) { + void *objp = slabp->s_mem + cachep->objsize * i; + + if (cachep->flags & SLAB_POISON) { +#ifdef CONFIG_DEBUG_PAGEALLOC + if ((cachep->objsize%PAGE_SIZE)==0 && OFF_SLAB(cachep)) + kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE,1); + else + check_poison_obj(cachep, objp); +#else + check_poison_obj(cachep, objp); +#endif + } + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "start of a freed object " + "was overwritten"); + if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "end of a freed object " + "was overwritten"); + } + if (cachep->dtor && !(cachep->flags & SLAB_POISON)) + (cachep->dtor)(objp+obj_dbghead(cachep), cachep, 0); + } +#else + if (cachep->dtor) { + int i; + for (i = 0; i < cachep->num; i++) { + void* objp = slabp->s_mem+cachep->objsize*i; + (cachep->dtor)(objp, cachep, 0); + } + } +#endif + + if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) { + struct slab_rcu *slab_rcu; + + slab_rcu = (struct slab_rcu *) slabp; + slab_rcu->cachep = cachep; + slab_rcu->addr = addr; + call_rcu(&slab_rcu->head, kmem_rcu_free); + } else { + kmem_freepages(cachep, addr); + if (OFF_SLAB(cachep)) + kmem_cache_free(cachep->slabp_cache, slabp); + } +} + +/** + * kmem_cache_create - Create a cache. + * @name: A string which is used in /proc/slabinfo to identify this cache. + * @size: The size of objects to be created in this cache. + * @align: The required alignment for the objects. + * @flags: SLAB flags + * @ctor: A constructor for the objects. + * @dtor: A destructor for the objects. + * + * Returns a ptr to the cache on success, NULL on failure. + * Cannot be called within a int, but can be interrupted. + * The @ctor is run when new pages are allocated by the cache + * and the @dtor is run before the pages are handed back. + * + * @name must be valid until the cache is destroyed. This implies that + * the module calling this has to destroy the cache before getting + * unloaded. + * + * The flags are + * + * %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5) + * to catch references to uninitialised memory. + * + * %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check + * for buffer overruns. + * + * %SLAB_NO_REAP - Don't automatically reap this cache when we're under + * memory pressure. + * + * %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware + * cacheline. This can be beneficial if you're counting cycles as closely + * as davem. + */ +kmem_cache_t * +kmem_cache_create (const char *name, size_t size, size_t align, + unsigned long flags, void (*ctor)(void*, kmem_cache_t *, unsigned long), + void (*dtor)(void*, kmem_cache_t *, unsigned long)) +{ + size_t left_over, slab_size, ralign; + kmem_cache_t *cachep = NULL; + + /* + * Sanity checks... these are all serious usage bugs. + */ + if ((!name) || + in_interrupt() || + (size < BYTES_PER_WORD) || + (size > (1<<MAX_OBJ_ORDER)*PAGE_SIZE) || + (dtor && !ctor)) { + printk(KERN_ERR "%s: Early error in slab %s\n", + __FUNCTION__, name); + BUG(); + } + +#if DEBUG + WARN_ON(strchr(name, ' ')); /* It confuses parsers */ + if ((flags & SLAB_DEBUG_INITIAL) && !ctor) { + /* No constructor, but inital state check requested */ + printk(KERN_ERR "%s: No con, but init state check " + "requested - %s\n", __FUNCTION__, name); + flags &= ~SLAB_DEBUG_INITIAL; + } + +#if FORCED_DEBUG + /* + * Enable redzoning and last user accounting, except for caches with + * large objects, if the increased size would increase the object size + * above the next power of two: caches with object sizes just above a + * power of two have a significant amount of internal fragmentation. + */ + if ((size < 4096 || fls(size-1) == fls(size-1+3*BYTES_PER_WORD))) + flags |= SLAB_RED_ZONE|SLAB_STORE_USER; + if (!(flags & SLAB_DESTROY_BY_RCU)) + flags |= SLAB_POISON; +#endif + if (flags & SLAB_DESTROY_BY_RCU) + BUG_ON(flags & SLAB_POISON); +#endif + if (flags & SLAB_DESTROY_BY_RCU) + BUG_ON(dtor); + + /* + * Always checks flags, a caller might be expecting debug + * support which isn't available. + */ + if (flags & ~CREATE_MASK) + BUG(); + + /* Check that size is in terms of words. This is needed to avoid + * unaligned accesses for some archs when redzoning is used, and makes + * sure any on-slab bufctl's are also correctly aligned. + */ + if (size & (BYTES_PER_WORD-1)) { + size += (BYTES_PER_WORD-1); + size &= ~(BYTES_PER_WORD-1); + } + + /* calculate out the final buffer alignment: */ + /* 1) arch recommendation: can be overridden for debug */ + if (flags & SLAB_HWCACHE_ALIGN) { + /* Default alignment: as specified by the arch code. + * Except if an object is really small, then squeeze multiple + * objects into one cacheline. + */ + ralign = cache_line_size(); + while (size <= ralign/2) + ralign /= 2; + } else { + ralign = BYTES_PER_WORD; + } + /* 2) arch mandated alignment: disables debug if necessary */ + if (ralign < ARCH_SLAB_MINALIGN) { + ralign = ARCH_SLAB_MINALIGN; + if (ralign > BYTES_PER_WORD) + flags &= ~(SLAB_RED_ZONE|SLAB_STORE_USER); + } + /* 3) caller mandated alignment: disables debug if necessary */ + if (ralign < align) { + ralign = align; + if (ralign > BYTES_PER_WORD) + flags &= ~(SLAB_RED_ZONE|SLAB_STORE_USER); + } + /* 4) Store it. Note that the debug code below can reduce + * the alignment to BYTES_PER_WORD. + */ + align = ralign; + + /* Get cache's description obj. */ + cachep = (kmem_cache_t *) kmem_cache_alloc(&cache_cache, SLAB_KERNEL); + if (!cachep) + goto opps; + memset(cachep, 0, sizeof(kmem_cache_t)); + +#if DEBUG + cachep->reallen = size; + + if (flags & SLAB_RED_ZONE) { + /* redzoning only works with word aligned caches */ + align = BYTES_PER_WORD; + + /* add space for red zone words */ + cachep->dbghead += BYTES_PER_WORD; + size += 2*BYTES_PER_WORD; + } + if (flags & SLAB_STORE_USER) { + /* user store requires word alignment and + * one word storage behind the end of the real + * object. + */ + align = BYTES_PER_WORD; + size += BYTES_PER_WORD; + } +#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC) + if (size > 128 && cachep->reallen > cache_line_size() && size < PAGE_SIZE) { + cachep->dbghead += PAGE_SIZE - size; + size = PAGE_SIZE; + } +#endif +#endif + + /* Determine if the slab management is 'on' or 'off' slab. */ + if (size >= (PAGE_SIZE>>3)) + /* + * Size is large, assume best to place the slab management obj + * off-slab (should allow better packing of objs). + */ + flags |= CFLGS_OFF_SLAB; + + size = ALIGN(size, align); + + if ((flags & SLAB_RECLAIM_ACCOUNT) && size <= PAGE_SIZE) { + /* + * A VFS-reclaimable slab tends to have most allocations + * as GFP_NOFS and we really don't want to have to be allocating + * higher-order pages when we are unable to shrink dcache. + */ + cachep->gfporder = 0; + cache_estimate(cachep->gfporder, size, align, flags, + &left_over, &cachep->num); + } else { + /* + * Calculate size (in pages) of slabs, and the num of objs per + * slab. This could be made much more intelligent. For now, + * try to avoid using high page-orders for slabs. When the + * gfp() funcs are more friendly towards high-order requests, + * this should be changed. + */ + do { + unsigned int break_flag = 0; +cal_wastage: + cache_estimate(cachep->gfporder, size, align, flags, + &left_over, &cachep->num); + if (break_flag) + break; + if (cachep->gfporder >= MAX_GFP_ORDER) + break; + if (!cachep->num) + goto next; + if (flags & CFLGS_OFF_SLAB && + cachep->num > offslab_limit) { + /* This num of objs will cause problems. */ + cachep->gfporder--; + break_flag++; + goto cal_wastage; + } + + /* + * Large num of objs is good, but v. large slabs are + * currently bad for the gfp()s. + */ + if (cachep->gfporder >= slab_break_gfp_order) + break; + + if ((left_over*8) <= (PAGE_SIZE<<cachep->gfporder)) + break; /* Acceptable internal fragmentation. */ +next: + cachep->gfporder++; + } while (1); + } + + if (!cachep->num) { + printk("kmem_cache_create: couldn't create cache %s.\n", name); + kmem_cache_free(&cache_cache, cachep); + cachep = NULL; + goto opps; + } + slab_size = ALIGN(cachep->num*sizeof(kmem_bufctl_t) + + sizeof(struct slab), align); + + /* + * If the slab has been placed off-slab, and we have enough space then + * move it on-slab. This is at the expense of any extra colouring. + */ + if (flags & CFLGS_OFF_SLAB && left_over >= slab_size) { + flags &= ~CFLGS_OFF_SLAB; + left_over -= slab_size; + } + + if (flags & CFLGS_OFF_SLAB) { + /* really off slab. No need for manual alignment */ + slab_size = cachep->num*sizeof(kmem_bufctl_t)+sizeof(struct slab); + } + + cachep->colour_off = cache_line_size(); + /* Offset must be a multiple of the alignment. */ + if (cachep->colour_off < align) + cachep->colour_off = align; + cachep->colour = left_over/cachep->colour_off; + cachep->slab_size = slab_size; + cachep->flags = flags; + cachep->gfpflags = 0; + if (flags & SLAB_CACHE_DMA) + cachep->gfpflags |= GFP_DMA; + spin_lock_init(&cachep->spinlock); + cachep->objsize = size; + /* NUMA */ + INIT_LIST_HEAD(&cachep->lists.slabs_full); + INIT_LIST_HEAD(&cachep->lists.slabs_partial); + INIT_LIST_HEAD(&cachep->lists.slabs_free); + + if (flags & CFLGS_OFF_SLAB) + cachep->slabp_cache = kmem_find_general_cachep(slab_size,0); + cachep->ctor = ctor; + cachep->dtor = dtor; + cachep->name = name; + + /* Don't let CPUs to come and go */ + lock_cpu_hotplug(); + + if (g_cpucache_up == FULL) { + enable_cpucache(cachep); + } else { + if (g_cpucache_up == NONE) { + /* Note: the first kmem_cache_create must create + * the cache that's used by kmalloc(24), otherwise + * the creation of further caches will BUG(). + */ + cachep->array[smp_processor_id()] = &initarray_generic.cache; + g_cpucache_up = PARTIAL; + } else { + cachep->array[smp_processor_id()] = kmalloc(sizeof(struct arraycache_init),GFP_KERNEL); + } + BUG_ON(!ac_data(cachep)); + ac_data(cachep)->avail = 0; + ac_data(cachep)->limit = BOOT_CPUCACHE_ENTRIES; + ac_data(cachep)->batchcount = 1; + ac_data(cachep)->touched = 0; + cachep->batchcount = 1; + cachep->limit = BOOT_CPUCACHE_ENTRIES; + cachep->free_limit = (1+num_online_cpus())*cachep->batchcount + + cachep->num; + } + + cachep->lists.next_reap = jiffies + REAPTIMEOUT_LIST3 + + ((unsigned long)cachep)%REAPTIMEOUT_LIST3; + + /* Need the semaphore to access the chain. */ + down(&cache_chain_sem); + { + struct list_head *p; + mm_segment_t old_fs; + + old_fs = get_fs(); + set_fs(KERNEL_DS); + list_for_each(p, &cache_chain) { + kmem_cache_t *pc = list_entry(p, kmem_cache_t, next); + char tmp; + /* This happens when the module gets unloaded and doesn't + destroy its slab cache and noone else reuses the vmalloc + area of the module. Print a warning. */ + if (__get_user(tmp,pc->name)) { + printk("SLAB: cache with size %d has lost its name\n", + pc->objsize); + continue; + } + if (!strcmp(pc->name,name)) { + printk("kmem_cache_create: duplicate cache %s\n",name); + up(&cache_chain_sem); + unlock_cpu_hotplug(); + BUG(); + } + } + set_fs(old_fs); + } + + /* cache setup completed, link it into the list */ + list_add(&cachep->next, &cache_chain); + up(&cache_chain_sem); + unlock_cpu_hotplug(); +opps: + if (!cachep && (flags & SLAB_PANIC)) + panic("kmem_cache_create(): failed to create slab `%s'\n", + name); + return cachep; +} +EXPORT_SYMBOL(kmem_cache_create); + +#if DEBUG +static void check_irq_off(void) +{ + BUG_ON(!irqs_disabled()); +} + +static void check_irq_on(void) +{ + BUG_ON(irqs_disabled()); +} + +static void check_spinlock_acquired(kmem_cache_t *cachep) +{ +#ifdef CONFIG_SMP + check_irq_off(); + BUG_ON(spin_trylock(&cachep->spinlock)); +#endif +} +#else +#define check_irq_off() do { } while(0) +#define check_irq_on() do { } while(0) +#define check_spinlock_acquired(x) do { } while(0) +#endif + +/* + * Waits for all CPUs to execute func(). + */ +static void smp_call_function_all_cpus(void (*func) (void *arg), void *arg) +{ + check_irq_on(); + preempt_disable(); + + local_irq_disable(); + func(arg); + local_irq_enable(); + + if (smp_call_function(func, arg, 1, 1)) + BUG(); + + preempt_enable(); +} + +static void drain_array_locked(kmem_cache_t* cachep, + struct array_cache *ac, int force); + +static void do_drain(void *arg) +{ + kmem_cache_t *cachep = (kmem_cache_t*)arg; + struct array_cache *ac; + + check_irq_off(); + ac = ac_data(cachep); + spin_lock(&cachep->spinlock); + free_block(cachep, &ac_entry(ac)[0], ac->avail); + spin_unlock(&cachep->spinlock); + ac->avail = 0; +} + +static void drain_cpu_caches(kmem_cache_t *cachep) +{ + smp_call_function_all_cpus(do_drain, cachep); + check_irq_on(); + spin_lock_irq(&cachep->spinlock); + if (cachep->lists.shared) + drain_array_locked(cachep, cachep->lists.shared, 1); + spin_unlock_irq(&cachep->spinlock); +} + + +/* NUMA shrink all list3s */ +static int __cache_shrink(kmem_cache_t *cachep) +{ + struct slab *slabp; + int ret; + + drain_cpu_caches(cachep); + + check_irq_on(); + spin_lock_irq(&cachep->spinlock); + + for(;;) { + struct list_head *p; + + p = cachep->lists.slabs_free.prev; + if (p == &cachep->lists.slabs_free) + break; + + slabp = list_entry(cachep->lists.slabs_free.prev, struct slab, list); +#if DEBUG + if (slabp->inuse) + BUG(); +#endif + list_del(&slabp->list); + + cachep->lists.free_objects -= cachep->num; + spin_unlock_irq(&cachep->spinlock); + slab_destroy(cachep, slabp); + spin_lock_irq(&cachep->spinlock); + } + ret = !list_empty(&cachep->lists.slabs_full) || + !list_empty(&cachep->lists.slabs_partial); + spin_unlock_irq(&cachep->spinlock); + return ret; +} + +/** + * kmem_cache_shrink - Shrink a cache. + * @cachep: The cache to shrink. + * + * Releases as many slabs as possible for a cache. + * To help debugging, a zero exit status indicates all slabs were released. + */ +int kmem_cache_shrink(kmem_cache_t *cachep) +{ + if (!cachep || in_interrupt()) + BUG(); + + return __cache_shrink(cachep); +} +EXPORT_SYMBOL(kmem_cache_shrink); + +/** + * kmem_cache_destroy - delete a cache + * @cachep: the cache to destroy + * + * Remove a kmem_cache_t object from the slab cache. + * Returns 0 on success. + * + * It is expected this function will be called by a module when it is + * unloaded. This will remove the cache completely, and avoid a duplicate + * cache being allocated each time a module is loaded and unloaded, if the + * module doesn't have persistent in-kernel storage across loads and unloads. + * + * The cache must be empty before calling this function. + * + * The caller must guarantee that noone will allocate memory from the cache + * during the kmem_cache_destroy(). + */ +int kmem_cache_destroy(kmem_cache_t * cachep) +{ + int i; + + if (!cachep || in_interrupt()) + BUG(); + + /* Don't let CPUs to come and go */ + lock_cpu_hotplug(); + + /* Find the cache in the chain of caches. */ + down(&cache_chain_sem); + /* + * the chain is never empty, cache_cache is never destroyed + */ + list_del(&cachep->next); + up(&cache_chain_sem); + + if (__cache_shrink(cachep)) { + slab_error(cachep, "Can't free all objects"); + down(&cache_chain_sem); + list_add(&cachep->next,&cache_chain); + up(&cache_chain_sem); + unlock_cpu_hotplug(); + return 1; + } + + if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU)) + synchronize_kernel(); + + /* no cpu_online check required here since we clear the percpu + * array on cpu offline and set this to NULL. + */ + for (i = 0; i < NR_CPUS; i++) + kfree(cachep->array[i]); + + /* NUMA: free the list3 structures */ + kfree(cachep->lists.shared); + cachep->lists.shared = NULL; + kmem_cache_free(&cache_cache, cachep); + + unlock_cpu_hotplug(); + + return 0; +} +EXPORT_SYMBOL(kmem_cache_destroy); + +/* Get the memory for a slab management obj. */ +static struct slab* alloc_slabmgmt(kmem_cache_t *cachep, + void *objp, int colour_off, unsigned int __nocast local_flags) +{ + struct slab *slabp; + + if (OFF_SLAB(cachep)) { + /* Slab management obj is off-slab. */ + slabp = kmem_cache_alloc(cachep->slabp_cache, local_flags); + if (!slabp) + return NULL; + } else { + slabp = objp+colour_off; + colour_off += cachep->slab_size; + } + slabp->inuse = 0; + slabp->colouroff = colour_off; + slabp->s_mem = objp+colour_off; + + return slabp; +} + +static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp) +{ + return (kmem_bufctl_t *)(slabp+1); +} + +static void cache_init_objs(kmem_cache_t *cachep, + struct slab *slabp, unsigned long ctor_flags) +{ + int i; + + for (i = 0; i < cachep->num; i++) { + void* objp = slabp->s_mem+cachep->objsize*i; +#if DEBUG + /* need to poison the objs? */ + if (cachep->flags & SLAB_POISON) + poison_obj(cachep, objp, POISON_FREE); + if (cachep->flags & SLAB_STORE_USER) + *dbg_userword(cachep, objp) = NULL; + + if (cachep->flags & SLAB_RED_ZONE) { + *dbg_redzone1(cachep, objp) = RED_INACTIVE; + *dbg_redzone2(cachep, objp) = RED_INACTIVE; + } + /* + * Constructors are not allowed to allocate memory from + * the same cache which they are a constructor for. + * Otherwise, deadlock. They must also be threaded. + */ + if (cachep->ctor && !(cachep->flags & SLAB_POISON)) + cachep->ctor(objp+obj_dbghead(cachep), cachep, ctor_flags); + + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone2(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "constructor overwrote the" + " end of an object"); + if (*dbg_redzone1(cachep, objp) != RED_INACTIVE) + slab_error(cachep, "constructor overwrote the" + " start of an object"); + } + if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep) && cachep->flags & SLAB_POISON) + kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 0); +#else + if (cachep->ctor) + cachep->ctor(objp, cachep, ctor_flags); +#endif + slab_bufctl(slabp)[i] = i+1; + } + slab_bufctl(slabp)[i-1] = BUFCTL_END; + slabp->free = 0; +} + +static void kmem_flagcheck(kmem_cache_t *cachep, unsigned int flags) +{ + if (flags & SLAB_DMA) { + if (!(cachep->gfpflags & GFP_DMA)) + BUG(); + } else { + if (cachep->gfpflags & GFP_DMA) + BUG(); + } +} + +static void set_slab_attr(kmem_cache_t *cachep, struct slab *slabp, void *objp) +{ + int i; + struct page *page; + + /* Nasty!!!!!! I hope this is OK. */ + i = 1 << cachep->gfporder; + page = virt_to_page(objp); + do { + SET_PAGE_CACHE(page, cachep); + SET_PAGE_SLAB(page, slabp); + page++; + } while (--i); +} + +/* + * Grow (by 1) the number of slabs within a cache. This is called by + * kmem_cache_alloc() when there are no active objs left in a cache. + */ +static int cache_grow(kmem_cache_t *cachep, unsigned int __nocast flags, int nodeid) +{ + struct slab *slabp; + void *objp; + size_t offset; + unsigned int local_flags; + unsigned long ctor_flags; + + /* Be lazy and only check for valid flags here, + * keeping it out of the critical path in kmem_cache_alloc(). + */ + if (flags & ~(SLAB_DMA|SLAB_LEVEL_MASK|SLAB_NO_GROW)) + BUG(); + if (flags & SLAB_NO_GROW) + return 0; + + ctor_flags = SLAB_CTOR_CONSTRUCTOR; + local_flags = (flags & SLAB_LEVEL_MASK); + if (!(local_flags & __GFP_WAIT)) + /* + * Not allowed to sleep. Need to tell a constructor about + * this - it might need to know... + */ + ctor_flags |= SLAB_CTOR_ATOMIC; + + /* About to mess with non-constant members - lock. */ + check_irq_off(); + spin_lock(&cachep->spinlock); + + /* Get colour for the slab, and cal the next value. */ + offset = cachep->colour_next; + cachep->colour_next++; + if (cachep->colour_next >= cachep->colour) + cachep->colour_next = 0; + offset *= cachep->colour_off; + + spin_unlock(&cachep->spinlock); + + if (local_flags & __GFP_WAIT) + local_irq_enable(); + + /* + * The test for missing atomic flag is performed here, rather than + * the more obvious place, simply to reduce the critical path length + * in kmem_cache_alloc(). If a caller is seriously mis-behaving they + * will eventually be caught here (where it matters). + */ + kmem_flagcheck(cachep, flags); + + + /* Get mem for the objs. */ + if (!(objp = kmem_getpages(cachep, flags, nodeid))) + goto failed; + + /* Get slab management. */ + if (!(slabp = alloc_slabmgmt(cachep, objp, offset, local_flags))) + goto opps1; + + set_slab_attr(cachep, slabp, objp); + + cache_init_objs(cachep, slabp, ctor_flags); + + if (local_flags & __GFP_WAIT) + local_irq_disable(); + check_irq_off(); + spin_lock(&cachep->spinlock); + + /* Make slab active. */ + list_add_tail(&slabp->list, &(list3_data(cachep)->slabs_free)); + STATS_INC_GROWN(cachep); + list3_data(cachep)->free_objects += cachep->num; + spin_unlock(&cachep->spinlock); + return 1; +opps1: + kmem_freepages(cachep, objp); +failed: + if (local_flags & __GFP_WAIT) + local_irq_disable(); + return 0; +} + +#if DEBUG + +/* + * Perform extra freeing checks: + * - detect bad pointers. + * - POISON/RED_ZONE checking + * - destructor calls, for caches with POISON+dtor + */ +static void kfree_debugcheck(const void *objp) +{ + struct page *page; + + if (!virt_addr_valid(objp)) { + printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n", + (unsigned long)objp); + BUG(); + } + page = virt_to_page(objp); + if (!PageSlab(page)) { + printk(KERN_ERR "kfree_debugcheck: bad ptr %lxh.\n", (unsigned long)objp); + BUG(); + } +} + +static void *cache_free_debugcheck(kmem_cache_t *cachep, void *objp, + void *caller) +{ + struct page *page; + unsigned int objnr; + struct slab *slabp; + + objp -= obj_dbghead(cachep); + kfree_debugcheck(objp); + page = virt_to_page(objp); + + if (GET_PAGE_CACHE(page) != cachep) { + printk(KERN_ERR "mismatch in kmem_cache_free: expected cache %p, got %p\n", + GET_PAGE_CACHE(page),cachep); + printk(KERN_ERR "%p is %s.\n", cachep, cachep->name); + printk(KERN_ERR "%p is %s.\n", GET_PAGE_CACHE(page), GET_PAGE_CACHE(page)->name); + WARN_ON(1); + } + slabp = GET_PAGE_SLAB(page); + + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone1(cachep, objp) != RED_ACTIVE || *dbg_redzone2(cachep, objp) != RED_ACTIVE) { + slab_error(cachep, "double free, or memory outside" + " object was overwritten"); + printk(KERN_ERR "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n", + objp, *dbg_redzone1(cachep, objp), *dbg_redzone2(cachep, objp)); + } + *dbg_redzone1(cachep, objp) = RED_INACTIVE; + *dbg_redzone2(cachep, objp) = RED_INACTIVE; + } + if (cachep->flags & SLAB_STORE_USER) + *dbg_userword(cachep, objp) = caller; + + objnr = (objp-slabp->s_mem)/cachep->objsize; + + BUG_ON(objnr >= cachep->num); + BUG_ON(objp != slabp->s_mem + objnr*cachep->objsize); + + if (cachep->flags & SLAB_DEBUG_INITIAL) { + /* Need to call the slab's constructor so the + * caller can perform a verify of its state (debugging). + * Called without the cache-lock held. + */ + cachep->ctor(objp+obj_dbghead(cachep), + cachep, SLAB_CTOR_CONSTRUCTOR|SLAB_CTOR_VERIFY); + } + if (cachep->flags & SLAB_POISON && cachep->dtor) { + /* we want to cache poison the object, + * call the destruction callback + */ + cachep->dtor(objp+obj_dbghead(cachep), cachep, 0); + } + if (cachep->flags & SLAB_POISON) { +#ifdef CONFIG_DEBUG_PAGEALLOC + if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) { + store_stackinfo(cachep, objp, (unsigned long)caller); + kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 0); + } else { + poison_obj(cachep, objp, POISON_FREE); + } +#else + poison_obj(cachep, objp, POISON_FREE); +#endif + } + return objp; +} + +static void check_slabp(kmem_cache_t *cachep, struct slab *slabp) +{ + kmem_bufctl_t i; + int entries = 0; + + check_spinlock_acquired(cachep); + /* Check slab's freelist to see if this obj is there. */ + for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) { + entries++; + if (entries > cachep->num || i >= cachep->num) + goto bad; + } + if (entries != cachep->num - slabp->inuse) { +bad: + printk(KERN_ERR "slab: Internal list corruption detected in cache '%s'(%d), slabp %p(%d). Hexdump:\n", + cachep->name, cachep->num, slabp, slabp->inuse); + for (i=0;i<sizeof(slabp)+cachep->num*sizeof(kmem_bufctl_t);i++) { + if ((i%16)==0) + printk("\n%03x:", i); + printk(" %02x", ((unsigned char*)slabp)[i]); + } + printk("\n"); + BUG(); + } +} +#else +#define kfree_debugcheck(x) do { } while(0) +#define cache_free_debugcheck(x,objp,z) (objp) +#define check_slabp(x,y) do { } while(0) +#endif + +static void *cache_alloc_refill(kmem_cache_t *cachep, unsigned int __nocast flags) +{ + int batchcount; + struct kmem_list3 *l3; + struct array_cache *ac; + + check_irq_off(); + ac = ac_data(cachep); +retry: + batchcount = ac->batchcount; + if (!ac->touched && batchcount > BATCHREFILL_LIMIT) { + /* if there was little recent activity on this + * cache, then perform only a partial refill. + * Otherwise we could generate refill bouncing. + */ + batchcount = BATCHREFILL_LIMIT; + } + l3 = list3_data(cachep); + + BUG_ON(ac->avail > 0); + spin_lock(&cachep->spinlock); + if (l3->shared) { + struct array_cache *shared_array = l3->shared; + if (shared_array->avail) { + if (batchcount > shared_array->avail) + batchcount = shared_array->avail; + shared_array->avail -= batchcount; + ac->avail = batchcount; + memcpy(ac_entry(ac), &ac_entry(shared_array)[shared_array->avail], + sizeof(void*)*batchcount); + shared_array->touched = 1; + goto alloc_done; + } + } + while (batchcount > 0) { + struct list_head *entry; + struct slab *slabp; + /* Get slab alloc is to come from. */ + entry = l3->slabs_partial.next; + if (entry == &l3->slabs_partial) { + l3->free_touched = 1; + entry = l3->slabs_free.next; + if (entry == &l3->slabs_free) + goto must_grow; + } + + slabp = list_entry(entry, struct slab, list); + check_slabp(cachep, slabp); + check_spinlock_acquired(cachep); + while (slabp->inuse < cachep->num && batchcount--) { + kmem_bufctl_t next; + STATS_INC_ALLOCED(cachep); + STATS_INC_ACTIVE(cachep); + STATS_SET_HIGH(cachep); + + /* get obj pointer */ + ac_entry(ac)[ac->avail++] = slabp->s_mem + slabp->free*cachep->objsize; + + slabp->inuse++; + next = slab_bufctl(slabp)[slabp->free]; +#if DEBUG + slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE; +#endif + slabp->free = next; + } + check_slabp(cachep, slabp); + + /* move slabp to correct slabp list: */ + list_del(&slabp->list); + if (slabp->free == BUFCTL_END) + list_add(&slabp->list, &l3->slabs_full); + else + list_add(&slabp->list, &l3->slabs_partial); + } + +must_grow: + l3->free_objects -= ac->avail; +alloc_done: + spin_unlock(&cachep->spinlock); + + if (unlikely(!ac->avail)) { + int x; + x = cache_grow(cachep, flags, -1); + + // cache_grow can reenable interrupts, then ac could change. + ac = ac_data(cachep); + if (!x && ac->avail == 0) // no objects in sight? abort + return NULL; + + if (!ac->avail) // objects refilled by interrupt? + goto retry; + } + ac->touched = 1; + return ac_entry(ac)[--ac->avail]; +} + +static inline void +cache_alloc_debugcheck_before(kmem_cache_t *cachep, unsigned int __nocast flags) +{ + might_sleep_if(flags & __GFP_WAIT); +#if DEBUG + kmem_flagcheck(cachep, flags); +#endif +} + +#if DEBUG +static void * +cache_alloc_debugcheck_after(kmem_cache_t *cachep, + unsigned long flags, void *objp, void *caller) +{ + if (!objp) + return objp; + if (cachep->flags & SLAB_POISON) { +#ifdef CONFIG_DEBUG_PAGEALLOC + if ((cachep->objsize % PAGE_SIZE) == 0 && OFF_SLAB(cachep)) + kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE, 1); + else + check_poison_obj(cachep, objp); +#else + check_poison_obj(cachep, objp); +#endif + poison_obj(cachep, objp, POISON_INUSE); + } + if (cachep->flags & SLAB_STORE_USER) + *dbg_userword(cachep, objp) = caller; + + if (cachep->flags & SLAB_RED_ZONE) { + if (*dbg_redzone1(cachep, objp) != RED_INACTIVE || *dbg_redzone2(cachep, objp) != RED_INACTIVE) { + slab_error(cachep, "double free, or memory outside" + " object was overwritten"); + printk(KERN_ERR "%p: redzone 1: 0x%lx, redzone 2: 0x%lx.\n", + objp, *dbg_redzone1(cachep, objp), *dbg_redzone2(cachep, objp)); + } + *dbg_redzone1(cachep, objp) = RED_ACTIVE; + *dbg_redzone2(cachep, objp) = RED_ACTIVE; + } + objp += obj_dbghead(cachep); + if (cachep->ctor && cachep->flags & SLAB_POISON) { + unsigned long ctor_flags = SLAB_CTOR_CONSTRUCTOR; + + if (!(flags & __GFP_WAIT)) + ctor_flags |= SLAB_CTOR_ATOMIC; + + cachep->ctor(objp, cachep, ctor_flags); + } + return objp; +} +#else +#define cache_alloc_debugcheck_after(a,b,objp,d) (objp) +#endif + + +static inline void *__cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) +{ + unsigned long save_flags; + void* objp; + struct array_cache *ac; + + cache_alloc_debugcheck_before(cachep, flags); + + local_irq_save(save_flags); + ac = ac_data(cachep); + if (likely(ac->avail)) { + STATS_INC_ALLOCHIT(cachep); + ac->touched = 1; + objp = ac_entry(ac)[--ac->avail]; + } else { + STATS_INC_ALLOCMISS(cachep); + objp = cache_alloc_refill(cachep, flags); + } + local_irq_restore(save_flags); + objp = cache_alloc_debugcheck_after(cachep, flags, objp, __builtin_return_address(0)); + return objp; +} + +/* + * NUMA: different approach needed if the spinlock is moved into + * the l3 structure + */ + +static void free_block(kmem_cache_t *cachep, void **objpp, int nr_objects) +{ + int i; + + check_spinlock_acquired(cachep); + + /* NUMA: move add into loop */ + cachep->lists.free_objects += nr_objects; + + for (i = 0; i < nr_objects; i++) { + void *objp = objpp[i]; + struct slab *slabp; + unsigned int objnr; + + slabp = GET_PAGE_SLAB(virt_to_page(objp)); + list_del(&slabp->list); + objnr = (objp - slabp->s_mem) / cachep->objsize; + check_slabp(cachep, slabp); +#if DEBUG + if (slab_bufctl(slabp)[objnr] != BUFCTL_FREE) { + printk(KERN_ERR "slab: double free detected in cache '%s', objp %p.\n", + cachep->name, objp); + BUG(); + } +#endif + slab_bufctl(slabp)[objnr] = slabp->free; + slabp->free = objnr; + STATS_DEC_ACTIVE(cachep); + slabp->inuse--; + check_slabp(cachep, slabp); + + /* fixup slab chains */ + if (slabp->inuse == 0) { + if (cachep->lists.free_objects > cachep->free_limit) { + cachep->lists.free_objects -= cachep->num; + slab_destroy(cachep, slabp); + } else { + list_add(&slabp->list, + &list3_data_ptr(cachep, objp)->slabs_free); + } + } else { + /* Unconditionally move a slab to the end of the + * partial list on free - maximum time for the + * other objects to be freed, too. + */ + list_add_tail(&slabp->list, + &list3_data_ptr(cachep, objp)->slabs_partial); + } + } +} + +static void cache_flusharray(kmem_cache_t *cachep, struct array_cache *ac) +{ + int batchcount; + + batchcount = ac->batchcount; +#if DEBUG + BUG_ON(!batchcount || batchcount > ac->avail); +#endif + check_irq_off(); + spin_lock(&cachep->spinlock); + if (cachep->lists.shared) { + struct array_cache *shared_array = cachep->lists.shared; + int max = shared_array->limit-shared_array->avail; + if (max) { + if (batchcount > max) + batchcount = max; + memcpy(&ac_entry(shared_array)[shared_array->avail], + &ac_entry(ac)[0], + sizeof(void*)*batchcount); + shared_array->avail += batchcount; + goto free_done; + } + } + + free_block(cachep, &ac_entry(ac)[0], batchcount); +free_done: +#if STATS + { + int i = 0; + struct list_head *p; + + p = list3_data(cachep)->slabs_free.next; + while (p != &(list3_data(cachep)->slabs_free)) { + struct slab *slabp; + + slabp = list_entry(p, struct slab, list); + BUG_ON(slabp->inuse); + + i++; + p = p->next; + } + STATS_SET_FREEABLE(cachep, i); + } +#endif + spin_unlock(&cachep->spinlock); + ac->avail -= batchcount; + memmove(&ac_entry(ac)[0], &ac_entry(ac)[batchcount], + sizeof(void*)*ac->avail); +} + +/* + * __cache_free + * Release an obj back to its cache. If the obj has a constructed + * state, it must be in this state _before_ it is released. + * + * Called with disabled ints. + */ +static inline void __cache_free(kmem_cache_t *cachep, void *objp) +{ + struct array_cache *ac = ac_data(cachep); + + check_irq_off(); + objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0)); + + if (likely(ac->avail < ac->limit)) { + STATS_INC_FREEHIT(cachep); + ac_entry(ac)[ac->avail++] = objp; + return; + } else { + STATS_INC_FREEMISS(cachep); + cache_flusharray(cachep, ac); + ac_entry(ac)[ac->avail++] = objp; + } +} + +/** + * kmem_cache_alloc - Allocate an object + * @cachep: The cache to allocate from. + * @flags: See kmalloc(). + * + * Allocate an object from this cache. The flags are only relevant + * if the cache has no available objects. + */ +void *kmem_cache_alloc(kmem_cache_t *cachep, unsigned int __nocast flags) +{ + return __cache_alloc(cachep, flags); +} +EXPORT_SYMBOL(kmem_cache_alloc); + +/** + * kmem_ptr_validate - check if an untrusted pointer might + * be a slab entry. + * @cachep: the cache we're checking against + * @ptr: pointer to validate + * + * This verifies that the untrusted pointer looks sane: + * it is _not_ a guarantee that the pointer is actually + * part of the slab cache in question, but it at least + * validates that the pointer can be dereferenced and + * looks half-way sane. + * + * Currently only used for dentry validation. + */ +int fastcall kmem_ptr_validate(kmem_cache_t *cachep, void *ptr) +{ + unsigned long addr = (unsigned long) ptr; + unsigned long min_addr = PAGE_OFFSET; + unsigned long align_mask = BYTES_PER_WORD-1; + unsigned long size = cachep->objsize; + struct page *page; + + if (unlikely(addr < min_addr)) + goto out; + if (unlikely(addr > (unsigned long)high_memory - size)) + goto out; + if (unlikely(addr & align_mask)) + goto out; + if (unlikely(!kern_addr_valid(addr))) + goto out; + if (unlikely(!kern_addr_valid(addr + size - 1))) + goto out; + page = virt_to_page(ptr); + if (unlikely(!PageSlab(page))) + goto out; + if (unlikely(GET_PAGE_CACHE(page) != cachep)) + goto out; + return 1; +out: + return 0; +} + +#ifdef CONFIG_NUMA +/** + * kmem_cache_alloc_node - Allocate an object on the specified node + * @cachep: The cache to allocate from. + * @flags: See kmalloc(). + * @nodeid: node number of the target node. + * + * Identical to kmem_cache_alloc, except that this function is slow + * and can sleep. And it will allocate memory on the given node, which + * can improve the performance for cpu bound structures. + */ +void *kmem_cache_alloc_node(kmem_cache_t *cachep, int nodeid) +{ + int loop; + void *objp; + struct slab *slabp; + kmem_bufctl_t next; + + for (loop = 0;;loop++) { + struct list_head *q; + + objp = NULL; + check_irq_on(); + spin_lock_irq(&cachep->spinlock); + /* walk through all partial and empty slab and find one + * from the right node */ + list_for_each(q,&cachep->lists.slabs_partial) { + slabp = list_entry(q, struct slab, list); + + if (page_to_nid(virt_to_page(slabp->s_mem)) == nodeid || + loop > 2) + goto got_slabp; + } + list_for_each(q, &cachep->lists.slabs_free) { + slabp = list_entry(q, struct slab, list); + + if (page_to_nid(virt_to_page(slabp->s_mem)) == nodeid || + loop > 2) + goto got_slabp; + } + spin_unlock_irq(&cachep->spinlock); + + local_irq_disable(); + if (!cache_grow(cachep, GFP_KERNEL, nodeid)) { + local_irq_enable(); + return NULL; + } + local_irq_enable(); + } +got_slabp: + /* found one: allocate object */ + check_slabp(cachep, slabp); + check_spinlock_acquired(cachep); + + STATS_INC_ALLOCED(cachep); + STATS_INC_ACTIVE(cachep); + STATS_SET_HIGH(cachep); + STATS_INC_NODEALLOCS(cachep); + + objp = slabp->s_mem + slabp->free*cachep->objsize; + + slabp->inuse++; + next = slab_bufctl(slabp)[slabp->free]; +#if DEBUG + slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE; +#endif + slabp->free = next; + check_slabp(cachep, slabp); + + /* move slabp to correct slabp list: */ + list_del(&slabp->list); + if (slabp->free == BUFCTL_END) + list_add(&slabp->list, &cachep->lists.slabs_full); + else + list_add(&slabp->list, &cachep->lists.slabs_partial); + + list3_data(cachep)->free_objects--; + spin_unlock_irq(&cachep->spinlock); + + objp = cache_alloc_debugcheck_after(cachep, GFP_KERNEL, objp, + __builtin_return_address(0)); + return objp; +} +EXPORT_SYMBOL(kmem_cache_alloc_node); + +#endif + +/** + * kmalloc - allocate memory + * @size: how many bytes of memory are required. + * @flags: the type of memory to allocate. + * + * kmalloc is the normal method of allocating memory + * in the kernel. + * + * The @flags argument may be one of: + * + * %GFP_USER - Allocate memory on behalf of user. May sleep. + * + * %GFP_KERNEL - Allocate normal kernel ram. May sleep. + * + * %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers. + * + * Additionally, the %GFP_DMA flag may be set to indicate the memory + * must be suitable for DMA. This can mean different things on different + * platforms. For example, on i386, it means that the memory must come + * from the first 16MB. + */ +void *__kmalloc(size_t size, unsigned int __nocast flags) +{ + kmem_cache_t *cachep; + + cachep = kmem_find_general_cachep(size, flags); + if (unlikely(cachep == NULL)) + return NULL; + return __cache_alloc(cachep, flags); +} +EXPORT_SYMBOL(__kmalloc); + +#ifdef CONFIG_SMP +/** + * __alloc_percpu - allocate one copy of the object for every present + * cpu in the system, zeroing them. + * Objects should be dereferenced using the per_cpu_ptr macro only. + * + * @size: how many bytes of memory are required. + * @align: the alignment, which can't be greater than SMP_CACHE_BYTES. + */ +void *__alloc_percpu(size_t size, size_t align) +{ + int i; + struct percpu_data *pdata = kmalloc(sizeof (*pdata), GFP_KERNEL); + + if (!pdata) + return NULL; + + for (i = 0; i < NR_CPUS; i++) { + if (!cpu_possible(i)) + continue; + pdata->ptrs[i] = kmem_cache_alloc_node( + kmem_find_general_cachep(size, GFP_KERNEL), + cpu_to_node(i)); + + if (!pdata->ptrs[i]) + goto unwind_oom; + memset(pdata->ptrs[i], 0, size); + } + + /* Catch derefs w/o wrappers */ + return (void *) (~(unsigned long) pdata); + +unwind_oom: + while (--i >= 0) { + if (!cpu_possible(i)) + continue; + kfree(pdata->ptrs[i]); + } + kfree(pdata); + return NULL; +} +EXPORT_SYMBOL(__alloc_percpu); +#endif + +/** + * kmem_cache_free - Deallocate an object + * @cachep: The cache the allocation was from. + * @objp: The previously allocated object. + * + * Free an object which was previously allocated from this + * cache. + */ +void kmem_cache_free(kmem_cache_t *cachep, void *objp) +{ + unsigned long flags; + + local_irq_save(flags); + __cache_free(cachep, objp); + local_irq_restore(flags); +} +EXPORT_SYMBOL(kmem_cache_free); + +/** + * kcalloc - allocate memory for an array. The memory is set to zero. + * @n: number of elements. + * @size: element size. + * @flags: the type of memory to allocate. + */ +void *kcalloc(size_t n, size_t size, unsigned int __nocast flags) +{ + void *ret = NULL; + + if (n != 0 && size > INT_MAX / n) + return ret; + + ret = kmalloc(n * size, flags); + if (ret) + memset(ret, 0, n * size); + return ret; +} +EXPORT_SYMBOL(kcalloc); + +/** + * kfree - free previously allocated memory + * @objp: pointer returned by kmalloc. + * + * Don't free memory not originally allocated by kmalloc() + * or you will run into trouble. + */ +void kfree(const void *objp) +{ + kmem_cache_t *c; + unsigned long flags; + + if (unlikely(!objp)) + return; + local_irq_save(flags); + kfree_debugcheck(objp); + c = GET_PAGE_CACHE(virt_to_page(objp)); + __cache_free(c, (void*)objp); + local_irq_restore(flags); +} +EXPORT_SYMBOL(kfree); + +#ifdef CONFIG_SMP +/** + * free_percpu - free previously allocated percpu memory + * @objp: pointer returned by alloc_percpu. + * + * Don't free memory not originally allocated by alloc_percpu() + * The complemented objp is to check for that. + */ +void +free_percpu(const void *objp) +{ + int i; + struct percpu_data *p = (struct percpu_data *) (~(unsigned long) objp); + + for (i = 0; i < NR_CPUS; i++) { + if (!cpu_possible(i)) + continue; + kfree(p->ptrs[i]); + } + kfree(p); +} +EXPORT_SYMBOL(free_percpu); +#endif + +unsigned int kmem_cache_size(kmem_cache_t *cachep) +{ + return obj_reallen(cachep); +} +EXPORT_SYMBOL(kmem_cache_size); + +struct ccupdate_struct { + kmem_cache_t *cachep; + struct array_cache *new[NR_CPUS]; +}; + +static void do_ccupdate_local(void *info) +{ + struct ccupdate_struct *new = (struct ccupdate_struct *)info; + struct array_cache *old; + + check_irq_off(); + old = ac_data(new->cachep); + + new->cachep->array[smp_processor_id()] = new->new[smp_processor_id()]; + new->new[smp_processor_id()] = old; +} + + +static int do_tune_cpucache(kmem_cache_t *cachep, int limit, int batchcount, + int shared) +{ + struct ccupdate_struct new; + struct array_cache *new_shared; + int i; + + memset(&new.new,0,sizeof(new.new)); + for (i = 0; i < NR_CPUS; i++) { + if (cpu_online(i)) { + new.new[i] = alloc_arraycache(i, limit, batchcount); + if (!new.new[i]) { + for (i--; i >= 0; i--) kfree(new.new[i]); + return -ENOMEM; + } + } else { + new.new[i] = NULL; + } + } + new.cachep = cachep; + + smp_call_function_all_cpus(do_ccupdate_local, (void *)&new); + + check_irq_on(); + spin_lock_irq(&cachep->spinlock); + cachep->batchcount = batchcount; + cachep->limit = limit; + cachep->free_limit = (1+num_online_cpus())*cachep->batchcount + cachep->num; + spin_unlock_irq(&cachep->spinlock); + + for (i = 0; i < NR_CPUS; i++) { + struct array_cache *ccold = new.new[i]; + if (!ccold) + continue; + spin_lock_irq(&cachep->spinlock); + free_block(cachep, ac_entry(ccold), ccold->avail); + spin_unlock_irq(&cachep->spinlock); + kfree(ccold); + } + new_shared = alloc_arraycache(-1, batchcount*shared, 0xbaadf00d); + if (new_shared) { + struct array_cache *old; + + spin_lock_irq(&cachep->spinlock); + old = cachep->lists.shared; + cachep->lists.shared = new_shared; + if (old) + free_block(cachep, ac_entry(old), old->avail); + spin_unlock_irq(&cachep->spinlock); + kfree(old); + } + + return 0; +} + + +static void enable_cpucache(kmem_cache_t *cachep) +{ + int err; + int limit, shared; + + /* The head array serves three purposes: + * - create a LIFO ordering, i.e. return objects that are cache-warm + * - reduce the number of spinlock operations. + * - reduce the number of linked list operations on the slab and + * bufctl chains: array operations are cheaper. + * The numbers are guessed, we should auto-tune as described by + * Bonwick. + */ + if (cachep->objsize > 131072) + limit = 1; + else if (cachep->objsize > PAGE_SIZE) + limit = 8; + else if (cachep->objsize > 1024) + limit = 24; + else if (cachep->objsize > 256) + limit = 54; + else + limit = 120; + + /* Cpu bound tasks (e.g. network routing) can exhibit cpu bound + * allocation behaviour: Most allocs on one cpu, most free operations + * on another cpu. For these cases, an efficient object passing between + * cpus is necessary. This is provided by a shared array. The array + * replaces Bonwick's magazine layer. + * On uniprocessor, it's functionally equivalent (but less efficient) + * to a larger limit. Thus disabled by default. + */ + shared = 0; +#ifdef CONFIG_SMP + if (cachep->objsize <= PAGE_SIZE) + shared = 8; +#endif + +#if DEBUG + /* With debugging enabled, large batchcount lead to excessively + * long periods with disabled local interrupts. Limit the + * batchcount + */ + if (limit > 32) + limit = 32; +#endif + err = do_tune_cpucache(cachep, limit, (limit+1)/2, shared); + if (err) + printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n", + cachep->name, -err); +} + +static void drain_array_locked(kmem_cache_t *cachep, + struct array_cache *ac, int force) +{ + int tofree; + + check_spinlock_acquired(cachep); + if (ac->touched && !force) { + ac->touched = 0; + } else if (ac->avail) { + tofree = force ? ac->avail : (ac->limit+4)/5; + if (tofree > ac->avail) { + tofree = (ac->avail+1)/2; + } + free_block(cachep, ac_entry(ac), tofree); + ac->avail -= tofree; + memmove(&ac_entry(ac)[0], &ac_entry(ac)[tofree], + sizeof(void*)*ac->avail); + } +} + +/** + * cache_reap - Reclaim memory from caches. + * + * Called from workqueue/eventd every few seconds. + * Purpose: + * - clear the per-cpu caches for this CPU. + * - return freeable pages to the main free memory pool. + * + * If we cannot acquire the cache chain semaphore then just give up - we'll + * try again on the next iteration. + */ +static void cache_reap(void *unused) +{ + struct list_head *walk; + + if (down_trylock(&cache_chain_sem)) { + /* Give up. Setup the next iteration. */ + schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC + smp_processor_id()); + return; + } + + list_for_each(walk, &cache_chain) { + kmem_cache_t *searchp; + struct list_head* p; + int tofree; + struct slab *slabp; + + searchp = list_entry(walk, kmem_cache_t, next); + + if (searchp->flags & SLAB_NO_REAP) + goto next; + + check_irq_on(); + + spin_lock_irq(&searchp->spinlock); + + drain_array_locked(searchp, ac_data(searchp), 0); + + if(time_after(searchp->lists.next_reap, jiffies)) + goto next_unlock; + + searchp->lists.next_reap = jiffies + REAPTIMEOUT_LIST3; + + if (searchp->lists.shared) + drain_array_locked(searchp, searchp->lists.shared, 0); + + if (searchp->lists.free_touched) { + searchp->lists.free_touched = 0; + goto next_unlock; + } + + tofree = (searchp->free_limit+5*searchp->num-1)/(5*searchp->num); + do { + p = list3_data(searchp)->slabs_free.next; + if (p == &(list3_data(searchp)->slabs_free)) + break; + + slabp = list_entry(p, struct slab, list); + BUG_ON(slabp->inuse); + list_del(&slabp->list); + STATS_INC_REAPED(searchp); + + /* Safe to drop the lock. The slab is no longer + * linked to the cache. + * searchp cannot disappear, we hold + * cache_chain_lock + */ + searchp->lists.free_objects -= searchp->num; + spin_unlock_irq(&searchp->spinlock); + slab_destroy(searchp, slabp); + spin_lock_irq(&searchp->spinlock); + } while(--tofree > 0); +next_unlock: + spin_unlock_irq(&searchp->spinlock); +next: + cond_resched(); + } + check_irq_on(); + up(&cache_chain_sem); + /* Setup the next iteration */ + schedule_delayed_work(&__get_cpu_var(reap_work), REAPTIMEOUT_CPUC + smp_processor_id()); +} + +#ifdef CONFIG_PROC_FS + +static void *s_start(struct seq_file *m, loff_t *pos) +{ + loff_t n = *pos; + struct list_head *p; + + down(&cache_chain_sem); + if (!n) { + /* + * Output format version, so at least we can change it + * without _too_ many complaints. + */ +#if STATS + seq_puts(m, "slabinfo - version: 2.1 (statistics)\n"); +#else + seq_puts(m, "slabinfo - version: 2.1\n"); +#endif + seq_puts(m, "# name <active_objs> <num_objs> <objsize> <objperslab> <pagesperslab>"); + seq_puts(m, " : tunables <limit> <batchcount> <sharedfactor>"); + seq_puts(m, " : slabdata <active_slabs> <num_slabs> <sharedavail>"); +#if STATS + seq_puts(m, " : globalstat <listallocs> <maxobjs> <grown> <reaped>" + " <error> <maxfreeable> <freelimit> <nodeallocs>"); + seq_puts(m, " : cpustat <allochit> <allocmiss> <freehit> <freemiss>"); +#endif + seq_putc(m, '\n'); + } + p = cache_chain.next; + while (n--) { + p = p->next; + if (p == &cache_chain) + return NULL; + } + return list_entry(p, kmem_cache_t, next); +} + +static void *s_next(struct seq_file *m, void *p, loff_t *pos) +{ + kmem_cache_t *cachep = p; + ++*pos; + return cachep->next.next == &cache_chain ? NULL + : list_entry(cachep->next.next, kmem_cache_t, next); +} + +static void s_stop(struct seq_file *m, void *p) +{ + up(&cache_chain_sem); +} + +static int s_show(struct seq_file *m, void *p) +{ + kmem_cache_t *cachep = p; + struct list_head *q; + struct slab *slabp; + unsigned long active_objs; + unsigned long num_objs; + unsigned long active_slabs = 0; + unsigned long num_slabs; + const char *name; + char *error = NULL; + + check_irq_on(); + spin_lock_irq(&cachep->spinlock); + active_objs = 0; + num_slabs = 0; + list_for_each(q,&cachep->lists.slabs_full) { + slabp = list_entry(q, struct slab, list); + if (slabp->inuse != cachep->num && !error) + error = "slabs_full accounting error"; + active_objs += cachep->num; + active_slabs++; + } + list_for_each(q,&cachep->lists.slabs_partial) { + slabp = list_entry(q, struct slab, list); + if (slabp->inuse == cachep->num && !error) + error = "slabs_partial inuse accounting error"; + if (!slabp->inuse && !error) + error = "slabs_partial/inuse accounting error"; + active_objs += slabp->inuse; + active_slabs++; + } + list_for_each(q,&cachep->lists.slabs_free) { + slabp = list_entry(q, struct slab, list); + if (slabp->inuse && !error) + error = "slabs_free/inuse accounting error"; + num_slabs++; + } + num_slabs+=active_slabs; + num_objs = num_slabs*cachep->num; + if (num_objs - active_objs != cachep->lists.free_objects && !error) + error = "free_objects accounting error"; + + name = cachep->name; + if (error) + printk(KERN_ERR "slab: cache %s error: %s\n", name, error); + + seq_printf(m, "%-17s %6lu %6lu %6u %4u %4d", + name, active_objs, num_objs, cachep->objsize, + cachep->num, (1<<cachep->gfporder)); + seq_printf(m, " : tunables %4u %4u %4u", + cachep->limit, cachep->batchcount, + cachep->lists.shared->limit/cachep->batchcount); + seq_printf(m, " : slabdata %6lu %6lu %6u", + active_slabs, num_slabs, cachep->lists.shared->avail); +#if STATS + { /* list3 stats */ + unsigned long high = cachep->high_mark; + unsigned long allocs = cachep->num_allocations; + unsigned long grown = cachep->grown; + unsigned long reaped = cachep->reaped; + unsigned long errors = cachep->errors; + unsigned long max_freeable = cachep->max_freeable; + unsigned long free_limit = cachep->free_limit; + unsigned long node_allocs = cachep->node_allocs; + + seq_printf(m, " : globalstat %7lu %6lu %5lu %4lu %4lu %4lu %4lu %4lu", + allocs, high, grown, reaped, errors, + max_freeable, free_limit, node_allocs); + } + /* cpu stats */ + { + unsigned long allochit = atomic_read(&cachep->allochit); + unsigned long allocmiss = atomic_read(&cachep->allocmiss); + unsigned long freehit = atomic_read(&cachep->freehit); + unsigned long freemiss = atomic_read(&cachep->freemiss); + + seq_printf(m, " : cpustat %6lu %6lu %6lu %6lu", + allochit, allocmiss, freehit, freemiss); + } +#endif + seq_putc(m, '\n'); + spin_unlock_irq(&cachep->spinlock); + return 0; +} + +/* + * slabinfo_op - iterator that generates /proc/slabinfo + * + * Output layout: + * cache-name + * num-active-objs + * total-objs + * object size + * num-active-slabs + * total-slabs + * num-pages-per-slab + * + further values on SMP and with statistics enabled + */ + +struct seq_operations slabinfo_op = { + .start = s_start, + .next = s_next, + .stop = s_stop, + .show = s_show, +}; + +#define MAX_SLABINFO_WRITE 128 +/** + * slabinfo_write - Tuning for the slab allocator + * @file: unused + * @buffer: user buffer + * @count: data length + * @ppos: unused + */ +ssize_t slabinfo_write(struct file *file, const char __user *buffer, + size_t count, loff_t *ppos) +{ + char kbuf[MAX_SLABINFO_WRITE+1], *tmp; + int limit, batchcount, shared, res; + struct list_head *p; + + if (count > MAX_SLABINFO_WRITE) + return -EINVAL; + if (copy_from_user(&kbuf, buffer, count)) + return -EFAULT; + kbuf[MAX_SLABINFO_WRITE] = '\0'; + + tmp = strchr(kbuf, ' '); + if (!tmp) + return -EINVAL; + *tmp = '\0'; + tmp++; + if (sscanf(tmp, " %d %d %d", &limit, &batchcount, &shared) != 3) + return -EINVAL; + + /* Find the cache in the chain of caches. */ + down(&cache_chain_sem); + res = -EINVAL; + list_for_each(p,&cache_chain) { + kmem_cache_t *cachep = list_entry(p, kmem_cache_t, next); + + if (!strcmp(cachep->name, kbuf)) { + if (limit < 1 || + batchcount < 1 || + batchcount > limit || + shared < 0) { + res = -EINVAL; + } else { + res = do_tune_cpucache(cachep, limit, batchcount, shared); + } + break; + } + } + up(&cache_chain_sem); + if (res >= 0) + res = count; + return res; +} +#endif + +unsigned int ksize(const void *objp) +{ + kmem_cache_t *c; + unsigned long flags; + unsigned int size = 0; + + if (likely(objp != NULL)) { + local_irq_save(flags); + c = GET_PAGE_CACHE(virt_to_page(objp)); + size = kmem_cache_size(c); + local_irq_restore(flags); + } + + return size; +} |
