Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

4759 lines (4158 sloc) 124.844 kb
/*
* 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 initializations 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 struct kmem_cache 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 mutex 'slab_mutex'.
* 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.
*
* 15 March 2005. NUMA slab allocator.
* Shai Fultheim <shai@scalex86.org>.
* Shobhit Dayal <shobhit@calsoftinc.com>
* Alok N Kataria <alokk@calsoftinc.com>
* Christoph Lameter <christoph@lameter.com>
*
* Modified the slab allocator to be node aware on NUMA systems.
* Each node has its own list of partial, free and full slabs.
* All object allocations for a node occur from node specific slab lists.
*/
#include <linux/slab.h>
#include "slab.h"
#include <linux/mm.h>
#include <linux/poison.h>
#include <linux/swap.h>
#include <linux/cache.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/cpuset.h>
#include <linux/proc_fs.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 <linux/string.h>
#include <linux/uaccess.h>
#include <linux/nodemask.h>
#include <linux/kmemleak.h>
#include <linux/mempolicy.h>
#include <linux/mutex.h>
#include <linux/fault-inject.h>
#include <linux/rtmutex.h>
#include <linux/reciprocal_div.h>
#include <linux/debugobjects.h>
#include <linux/kmemcheck.h>
#include <linux/memory.h>
#include <linux/prefetch.h>
#include <net/sock.h>
#include <asm/cacheflush.h>
#include <asm/tlbflush.h>
#include <asm/page.h>
#include <trace/events/kmem.h>
#include "internal.h"
/*
* DEBUG - 1 for kmem_cache_create() to honour; 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 *)
#define REDZONE_ALIGN max(BYTES_PER_WORD, __alignof__(unsigned long long))
#ifndef ARCH_KMALLOC_FLAGS
#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
#endif
/*
* true if a page was allocated from pfmemalloc reserves for network-based
* swap
*/
static bool pfmemalloc_active __read_mostly;
/* Legal flag mask for kmem_cache_create(). */
#if DEBUG
# define CREATE_MASK (SLAB_RED_ZONE | \
SLAB_POISON | SLAB_HWCACHE_ALIGN | \
SLAB_CACHE_DMA | \
SLAB_STORE_USER | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
#else
# define CREATE_MASK (SLAB_HWCACHE_ALIGN | \
SLAB_CACHE_DMA | \
SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
SLAB_DESTROY_BY_RCU | SLAB_MEM_SPREAD | \
SLAB_DEBUG_OBJECTS | SLAB_NOLEAKTRACE | SLAB_NOTRACK)
#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.
*/
typedef unsigned int kmem_bufctl_t;
#define BUFCTL_END (((kmem_bufctl_t)(~0U))-0)
#define BUFCTL_FREE (((kmem_bufctl_t)(~0U))-1)
#define BUFCTL_ACTIVE (((kmem_bufctl_t)(~0U))-2)
#define SLAB_LIMIT (((kmem_bufctl_t)(~0U))-3)
/*
* 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.
*/
struct slab_rcu {
struct rcu_head head;
struct kmem_cache *cachep;
void *addr;
};
/*
* 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 {
union {
struct {
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;
unsigned short nodeid;
};
struct slab_rcu __slab_cover_slab_rcu;
};
};
/*
* struct array_cache
*
* 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;
spinlock_t lock;
void *entry[]; /*
* Must have this definition in here for the proper
* alignment of array_cache. Also simplifies accessing
* the entries.
*
* Entries should not be directly dereferenced as
* entries belonging to slabs marked pfmemalloc will
* have the lower bits set SLAB_OBJ_PFMEMALLOC
*/
};
#define SLAB_OBJ_PFMEMALLOC 1
static inline bool is_obj_pfmemalloc(void *objp)
{
return (unsigned long)objp & SLAB_OBJ_PFMEMALLOC;
}
static inline void set_obj_pfmemalloc(void **objp)
{
*objp = (void *)((unsigned long)*objp | SLAB_OBJ_PFMEMALLOC);
return;
}
static inline void clear_obj_pfmemalloc(void **objp)
{
*objp = (void *)((unsigned long)*objp & ~SLAB_OBJ_PFMEMALLOC);
}
/*
* 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 for all objects.
*/
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;
unsigned int free_limit;
unsigned int colour_next; /* Per-node cache coloring */
spinlock_t list_lock;
struct array_cache *shared; /* shared per node */
struct array_cache **alien; /* on other nodes */
unsigned long next_reap; /* updated without locking */
int free_touched; /* updated without locking */
};
/*
* Need this for bootstrapping a per node allocator.
*/
#define NUM_INIT_LISTS (3 * MAX_NUMNODES)
static struct kmem_list3 __initdata initkmem_list3[NUM_INIT_LISTS];
#define CACHE_CACHE 0
#define SIZE_AC MAX_NUMNODES
#define SIZE_L3 (2 * MAX_NUMNODES)
static int drain_freelist(struct kmem_cache *cache,
struct kmem_list3 *l3, int tofree);
static void free_block(struct kmem_cache *cachep, void **objpp, int len,
int node);
static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
static void cache_reap(struct work_struct *unused);
/*
* This function must be completely optimized away if a constant is passed to
* it. Mostly the same as what is in linux/slab.h except it returns an index.
*/
static __always_inline int index_of(const size_t size)
{
extern void __bad_size(void);
if (__builtin_constant_p(size)) {
int i = 0;
#define CACHE(x) \
if (size <=x) \
return i; \
else \
i++;
#include <linux/kmalloc_sizes.h>
#undef CACHE
__bad_size();
} else
__bad_size();
return 0;
}
static int slab_early_init = 1;
#define INDEX_AC index_of(sizeof(struct arraycache_init))
#define INDEX_L3 index_of(sizeof(struct kmem_list3))
static void kmem_list3_init(struct kmem_list3 *parent)
{
INIT_LIST_HEAD(&parent->slabs_full);
INIT_LIST_HEAD(&parent->slabs_partial);
INIT_LIST_HEAD(&parent->slabs_free);
parent->shared = NULL;
parent->alien = NULL;
parent->colour_next = 0;
spin_lock_init(&parent->list_lock);
parent->free_objects = 0;
parent->free_touched = 0;
}
#define MAKE_LIST(cachep, listp, slab, nodeid) \
do { \
INIT_LIST_HEAD(listp); \
list_splice(&(cachep->nodelists[nodeid]->slab), listp); \
} while (0)
#define MAKE_ALL_LISTS(cachep, ptr, nodeid) \
do { \
MAKE_LIST((cachep), (&(ptr)->slabs_full), slabs_full, nodeid); \
MAKE_LIST((cachep), (&(ptr)->slabs_partial), slabs_partial, nodeid); \
MAKE_LIST((cachep), (&(ptr)->slabs_free), slabs_free, nodeid); \
} while (0)
#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.
*
* OTOH 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_ADD_REAPED(x,y) ((x)->reaped += (y))
#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_INC_NODEFREES(x) ((x)->node_frees++)
#define STATS_INC_ACOVERFLOW(x) ((x)->node_overflow++)
#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_ADD_REAPED(x,y) do { (void)(y); } 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_INC_NODEFREES(x) do { } while (0)
#define STATS_INC_ACOVERFLOW(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
/*
* memory layout of objects:
* 0 : objp
* 0 .. cachep->obj_offset - 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->obj_offset - BYTES_PER_WORD .. cachep->obj_offset - 1:
* redzone word.
* cachep->obj_offset: The real object.
* cachep->size - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
* cachep->size - 1* BYTES_PER_WORD: last caller address
* [BYTES_PER_WORD long]
*/
static int obj_offset(struct kmem_cache *cachep)
{
return cachep->obj_offset;
}
static unsigned long long *dbg_redzone1(struct kmem_cache *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
return (unsigned long long*) (objp + obj_offset(cachep) -
sizeof(unsigned long long));
}
static unsigned long long *dbg_redzone2(struct kmem_cache *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
if (cachep->flags & SLAB_STORE_USER)
return (unsigned long long *)(objp + cachep->size -
sizeof(unsigned long long) -
REDZONE_ALIGN);
return (unsigned long long *) (objp + cachep->size -
sizeof(unsigned long long));
}
static void **dbg_userword(struct kmem_cache *cachep, void *objp)
{
BUG_ON(!(cachep->flags & SLAB_STORE_USER));
return (void **)(objp + cachep->size - BYTES_PER_WORD);
}
#else
#define obj_offset(x) 0
#define dbg_redzone1(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
#define dbg_redzone2(cachep, objp) ({BUG(); (unsigned long long *)NULL;})
#define dbg_userword(cachep, objp) ({BUG(); (void **)NULL;})
#endif
#ifdef CONFIG_TRACING
size_t slab_buffer_size(struct kmem_cache *cachep)
{
return cachep->size;
}
EXPORT_SYMBOL(slab_buffer_size);
#endif
/*
* Do not go above this order unless 0 objects fit into the slab or
* overridden on the command line.
*/
#define SLAB_MAX_ORDER_HI 1
#define SLAB_MAX_ORDER_LO 0
static int slab_max_order = SLAB_MAX_ORDER_LO;
static bool slab_max_order_set __initdata;
static inline struct kmem_cache *page_get_cache(struct page *page)
{
page = compound_head(page);
BUG_ON(!PageSlab(page));
return page->slab_cache;
}
static inline struct kmem_cache *virt_to_cache(const void *obj)
{
struct page *page = virt_to_head_page(obj);
return page->slab_cache;
}
static inline struct slab *virt_to_slab(const void *obj)
{
struct page *page = virt_to_head_page(obj);
VM_BUG_ON(!PageSlab(page));
return page->slab_page;
}
static inline void *index_to_obj(struct kmem_cache *cache, struct slab *slab,
unsigned int idx)
{
return slab->s_mem + cache->size * idx;
}
/*
* We want to avoid an expensive divide : (offset / cache->size)
* Using the fact that size is a constant for a particular cache,
* we can replace (offset / cache->size) by
* reciprocal_divide(offset, cache->reciprocal_buffer_size)
*/
static inline unsigned int obj_to_index(const struct kmem_cache *cache,
const struct slab *slab, void *obj)
{
u32 offset = (obj - slab->s_mem);
return reciprocal_divide(offset, cache->reciprocal_buffer_size);
}
/*
* 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 struct kmem_list3 *cache_cache_nodelists[MAX_NUMNODES];
static struct kmem_cache cache_cache = {
.nodelists = cache_cache_nodelists,
.batchcount = 1,
.limit = BOOT_CPUCACHE_ENTRIES,
.shared = 1,
.size = sizeof(struct kmem_cache),
.name = "kmem_cache",
};
#define BAD_ALIEN_MAGIC 0x01020304ul
#ifdef CONFIG_LOCKDEP
/*
* Slab sometimes uses the kmalloc slabs to store the slab headers
* for other slabs "off slab".
* The locking for this is tricky in that it nests within the locks
* of all other slabs in a few places; to deal with this special
* locking we put on-slab caches into a separate lock-class.
*
* We set lock class for alien array caches which are up during init.
* The lock annotation will be lost if all cpus of a node goes down and
* then comes back up during hotplug
*/
static struct lock_class_key on_slab_l3_key;
static struct lock_class_key on_slab_alc_key;
static struct lock_class_key debugobj_l3_key;
static struct lock_class_key debugobj_alc_key;
static void slab_set_lock_classes(struct kmem_cache *cachep,
struct lock_class_key *l3_key, struct lock_class_key *alc_key,
int q)
{
struct array_cache **alc;
struct kmem_list3 *l3;
int r;
l3 = cachep->nodelists[q];
if (!l3)
return;
lockdep_set_class(&l3->list_lock, l3_key);
alc = l3->alien;
/*
* FIXME: This check for BAD_ALIEN_MAGIC
* should go away when common slab code is taught to
* work even without alien caches.
* Currently, non NUMA code returns BAD_ALIEN_MAGIC
* for alloc_alien_cache,
*/
if (!alc || (unsigned long)alc == BAD_ALIEN_MAGIC)
return;
for_each_node(r) {
if (alc[r])
lockdep_set_class(&alc[r]->lock, alc_key);
}
}
static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
{
slab_set_lock_classes(cachep, &debugobj_l3_key, &debugobj_alc_key, node);
}
static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
{
int node;
for_each_online_node(node)
slab_set_debugobj_lock_classes_node(cachep, node);
}
static void init_node_lock_keys(int q)
{
struct cache_sizes *s = malloc_sizes;
if (slab_state < UP)
return;
for (s = malloc_sizes; s->cs_size != ULONG_MAX; s++) {
struct kmem_list3 *l3;
l3 = s->cs_cachep->nodelists[q];
if (!l3 || OFF_SLAB(s->cs_cachep))
continue;
slab_set_lock_classes(s->cs_cachep, &on_slab_l3_key,
&on_slab_alc_key, q);
}
}
static inline void init_lock_keys(void)
{
int node;
for_each_node(node)
init_node_lock_keys(node);
}
#else
static void init_node_lock_keys(int q)
{
}
static inline void init_lock_keys(void)
{
}
static void slab_set_debugobj_lock_classes_node(struct kmem_cache *cachep, int node)
{
}
static void slab_set_debugobj_lock_classes(struct kmem_cache *cachep)
{
}
#endif
static DEFINE_PER_CPU(struct delayed_work, slab_reap_work);
static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
{
return cachep->array[smp_processor_id()];
}
static inline struct kmem_cache *__find_general_cachep(size_t size,
gfp_t 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(malloc_sizes[INDEX_AC].cs_cachep == NULL);
#endif
if (!size)
return ZERO_SIZE_PTR;
while (size > csizep->cs_size)
csizep++;
/*
* Really subtle: The last entry with cs->cs_size==ULONG_MAX
* has cs_{dma,}cachep==NULL. Thus no special case
* for large kmalloc calls required.
*/
#ifdef CONFIG_ZONE_DMA
if (unlikely(gfpflags & GFP_DMA))
return csizep->cs_dmacachep;
#endif
return csizep->cs_cachep;
}
static struct kmem_cache *kmem_find_general_cachep(size_t size, gfp_t gfpflags)
{
return __find_general_cachep(size, gfpflags);
}
static size_t slab_mgmt_size(size_t nr_objs, size_t align)
{
return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
}
/*
* Calculate the number of objects and left-over bytes for a given buffer size.
*/
static void cache_estimate(unsigned long gfporder, size_t buffer_size,
size_t align, int flags, size_t *left_over,
unsigned int *num)
{
int nr_objs;
size_t mgmt_size;
size_t slab_size = PAGE_SIZE << gfporder;
/*
* The slab management structure can be either off the slab or
* on it. For the latter case, the memory allocated for a
* slab is used for:
*
* - The struct slab
* - One kmem_bufctl_t for each object
* - Padding to respect alignment of @align
* - @buffer_size bytes for each object
*
* If the slab management structure is off the slab, then the
* alignment will already be calculated into the size. Because
* the slabs are all pages aligned, the objects will be at the
* correct alignment when allocated.
*/
if (flags & CFLGS_OFF_SLAB) {
mgmt_size = 0;
nr_objs = slab_size / buffer_size;
if (nr_objs > SLAB_LIMIT)
nr_objs = SLAB_LIMIT;
} else {
/*
* Ignore padding for the initial guess. The padding
* is at most @align-1 bytes, and @buffer_size is at
* least @align. In the worst case, this result will
* be one greater than the number of objects that fit
* into the memory allocation when taking the padding
* into account.
*/
nr_objs = (slab_size - sizeof(struct slab)) /
(buffer_size + sizeof(kmem_bufctl_t));
/*
* This calculated number will be either the right
* amount, or one greater than what we want.
*/
if (slab_mgmt_size(nr_objs, align) + nr_objs*buffer_size
> slab_size)
nr_objs--;
if (nr_objs > SLAB_LIMIT)
nr_objs = SLAB_LIMIT;
mgmt_size = slab_mgmt_size(nr_objs, align);
}
*num = nr_objs;
*left_over = slab_size - nr_objs*buffer_size - mgmt_size;
}
#define slab_error(cachep, msg) __slab_error(__func__, cachep, msg)
static void __slab_error(const char *function, struct kmem_cache *cachep,
char *msg)
{
printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
function, cachep->name, msg);
dump_stack();
}
/*
* By default on NUMA we use alien caches to stage the freeing of
* objects allocated from other nodes. This causes massive memory
* inefficiencies when using fake NUMA setup to split memory into a
* large number of small nodes, so it can be disabled on the command
* line
*/
static int use_alien_caches __read_mostly = 1;
static int __init noaliencache_setup(char *s)
{
use_alien_caches = 0;
return 1;
}
__setup("noaliencache", noaliencache_setup);
static int __init slab_max_order_setup(char *str)
{
get_option(&str, &slab_max_order);
slab_max_order = slab_max_order < 0 ? 0 :
min(slab_max_order, MAX_ORDER - 1);
slab_max_order_set = true;
return 1;
}
__setup("slab_max_order=", slab_max_order_setup);
#ifdef CONFIG_NUMA
/*
* Special reaping functions for NUMA systems called from cache_reap().
* These take care of doing round robin flushing of alien caches (containing
* objects freed on different nodes from which they were allocated) and the
* flushing of remote pcps by calling drain_node_pages.
*/
static DEFINE_PER_CPU(unsigned long, slab_reap_node);
static void init_reap_node(int cpu)
{
int node;
node = next_node(cpu_to_mem(cpu), node_online_map);
if (node == MAX_NUMNODES)
node = first_node(node_online_map);
per_cpu(slab_reap_node, cpu) = node;
}
static void next_reap_node(void)
{
int node = __this_cpu_read(slab_reap_node);
node = next_node(node, node_online_map);
if (unlikely(node >= MAX_NUMNODES))
node = first_node(node_online_map);
__this_cpu_write(slab_reap_node, node);
}
#else
#define init_reap_node(cpu) do { } while (0)
#define next_reap_node(void) do { } while (0)
#endif
/*
* 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 __cpuinit start_cpu_timer(int cpu)
{
struct delayed_work *reap_work = &per_cpu(slab_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->work.func == NULL) {
init_reap_node(cpu);
INIT_DELAYED_WORK_DEFERRABLE(reap_work, cache_reap);
schedule_delayed_work_on(cpu, reap_work,
__round_jiffies_relative(HZ, cpu));
}
}
static struct array_cache *alloc_arraycache(int node, int entries,
int batchcount, gfp_t gfp)
{
int memsize = sizeof(void *) * entries + sizeof(struct array_cache);
struct array_cache *nc = NULL;
nc = kmalloc_node(memsize, gfp, node);
/*
* The array_cache structures contain pointers to free object.
* However, when such objects are allocated or transferred to another
* cache the pointers are not cleared and they could be counted as
* valid references during a kmemleak scan. Therefore, kmemleak must
* not scan such objects.
*/
kmemleak_no_scan(nc);
if (nc) {
nc->avail = 0;
nc->limit = entries;
nc->batchcount = batchcount;
nc->touched = 0;
spin_lock_init(&nc->lock);
}
return nc;
}
static inline bool is_slab_pfmemalloc(struct slab *slabp)
{
struct page *page = virt_to_page(slabp->s_mem);
return PageSlabPfmemalloc(page);
}
/* Clears pfmemalloc_active if no slabs have pfmalloc set */
static void recheck_pfmemalloc_active(struct kmem_cache *cachep,
struct array_cache *ac)
{
struct kmem_list3 *l3 = cachep->nodelists[numa_mem_id()];
struct slab *slabp;
unsigned long flags;
if (!pfmemalloc_active)
return;
spin_lock_irqsave(&l3->list_lock, flags);
list_for_each_entry(slabp, &l3->slabs_full, list)
if (is_slab_pfmemalloc(slabp))
goto out;
list_for_each_entry(slabp, &l3->slabs_partial, list)
if (is_slab_pfmemalloc(slabp))
goto out;
list_for_each_entry(slabp, &l3->slabs_free, list)
if (is_slab_pfmemalloc(slabp))
goto out;
pfmemalloc_active = false;
out:
spin_unlock_irqrestore(&l3->list_lock, flags);
}
static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
gfp_t flags, bool force_refill)
{
int i;
void *objp = ac->entry[--ac->avail];
/* Ensure the caller is allowed to use objects from PFMEMALLOC slab */
if (unlikely(is_obj_pfmemalloc(objp))) {
struct kmem_list3 *l3;
if (gfp_pfmemalloc_allowed(flags)) {
clear_obj_pfmemalloc(&objp);
return objp;
}
/* The caller cannot use PFMEMALLOC objects, find another one */
for (i = 1; i < ac->avail; i++) {
/* If a !PFMEMALLOC object is found, swap them */
if (!is_obj_pfmemalloc(ac->entry[i])) {
objp = ac->entry[i];
ac->entry[i] = ac->entry[ac->avail];
ac->entry[ac->avail] = objp;
return objp;
}
}
/*
* If there are empty slabs on the slabs_free list and we are
* being forced to refill the cache, mark this one !pfmemalloc.
*/
l3 = cachep->nodelists[numa_mem_id()];
if (!list_empty(&l3->slabs_free) && force_refill) {
struct slab *slabp = virt_to_slab(objp);
ClearPageSlabPfmemalloc(virt_to_page(slabp->s_mem));
clear_obj_pfmemalloc(&objp);
recheck_pfmemalloc_active(cachep, ac);
return objp;
}
/* No !PFMEMALLOC objects available */
ac->avail++;
objp = NULL;
}
return objp;
}
static inline void *ac_get_obj(struct kmem_cache *cachep,
struct array_cache *ac, gfp_t flags, bool force_refill)
{
void *objp;
if (unlikely(sk_memalloc_socks()))
objp = __ac_get_obj(cachep, ac, flags, force_refill);
else
objp = ac->entry[--ac->avail];
return objp;
}
static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
void *objp)
{
if (unlikely(pfmemalloc_active)) {
/* Some pfmemalloc slabs exist, check if this is one */
struct page *page = virt_to_page(objp);
if (PageSlabPfmemalloc(page))
set_obj_pfmemalloc(&objp);
}
return objp;
}
static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
void *objp)
{
if (unlikely(sk_memalloc_socks()))
objp = __ac_put_obj(cachep, ac, objp);
ac->entry[ac->avail++] = objp;
}
/*
* Transfer objects in one arraycache to another.
* Locking must be handled by the caller.
*
* Return the number of entries transferred.
*/
static int transfer_objects(struct array_cache *to,
struct array_cache *from, unsigned int max)
{
/* Figure out how many entries to transfer */
int nr = min3(from->avail, max, to->limit - to->avail);
if (!nr)
return 0;
memcpy(to->entry + to->avail, from->entry + from->avail -nr,
sizeof(void *) *nr);
from->avail -= nr;
to->avail += nr;
return nr;
}
#ifndef CONFIG_NUMA
#define drain_alien_cache(cachep, alien) do { } while (0)
#define reap_alien(cachep, l3) do { } while (0)
static inline struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
{
return (struct array_cache **)BAD_ALIEN_MAGIC;
}
static inline void free_alien_cache(struct array_cache **ac_ptr)
{
}
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
{
return 0;
}
static inline void *alternate_node_alloc(struct kmem_cache *cachep,
gfp_t flags)
{
return NULL;
}
static inline void *____cache_alloc_node(struct kmem_cache *cachep,
gfp_t flags, int nodeid)
{
return NULL;
}
#else /* CONFIG_NUMA */
static void *____cache_alloc_node(struct kmem_cache *, gfp_t, int);
static void *alternate_node_alloc(struct kmem_cache *, gfp_t);
static struct array_cache **alloc_alien_cache(int node, int limit, gfp_t gfp)
{
struct array_cache **ac_ptr;
int memsize = sizeof(void *) * nr_node_ids;
int i;
if (limit > 1)
limit = 12;
ac_ptr = kzalloc_node(memsize, gfp, node);
if (ac_ptr) {
for_each_node(i) {
if (i == node || !node_online(i))
continue;
ac_ptr[i] = alloc_arraycache(node, limit, 0xbaadf00d, gfp);
if (!ac_ptr[i]) {
for (i--; i >= 0; i--)
kfree(ac_ptr[i]);
kfree(ac_ptr);
return NULL;
}
}
}
return ac_ptr;
}
static void free_alien_cache(struct array_cache **ac_ptr)
{
int i;
if (!ac_ptr)
return;
for_each_node(i)
kfree(ac_ptr[i]);
kfree(ac_ptr);
}
static void __drain_alien_cache(struct kmem_cache *cachep,
struct array_cache *ac, int node)
{
struct kmem_list3 *rl3 = cachep->nodelists[node];
if (ac->avail) {
spin_lock(&rl3->list_lock);
/*
* Stuff objects into the remote nodes shared array first.
* That way we could avoid the overhead of putting the objects
* into the free lists and getting them back later.
*/
if (rl3->shared)
transfer_objects(rl3->shared, ac, ac->limit);
free_block(cachep, ac->entry, ac->avail, node);
ac->avail = 0;
spin_unlock(&rl3->list_lock);
}
}
/*
* Called from cache_reap() to regularly drain alien caches round robin.
*/
static void reap_alien(struct kmem_cache *cachep, struct kmem_list3 *l3)
{
int node = __this_cpu_read(slab_reap_node);
if (l3->alien) {
struct array_cache *ac = l3->alien[node];
if (ac && ac->avail && spin_trylock_irq(&ac->lock)) {
__drain_alien_cache(cachep, ac, node);
spin_unlock_irq(&ac->lock);
}
}
}
static void drain_alien_cache(struct kmem_cache *cachep,
struct array_cache **alien)
{
int i = 0;
struct array_cache *ac;
unsigned long flags;
for_each_online_node(i) {
ac = alien[i];
if (ac) {
spin_lock_irqsave(&ac->lock, flags);
__drain_alien_cache(cachep, ac, i);
spin_unlock_irqrestore(&ac->lock, flags);
}
}
}
static inline int cache_free_alien(struct kmem_cache *cachep, void *objp)
{
struct slab *slabp = virt_to_slab(objp);
int nodeid = slabp->nodeid;
struct kmem_list3 *l3;
struct array_cache *alien = NULL;
int node;
node = numa_mem_id();
/*
* Make sure we are not freeing a object from another node to the array
* cache on this cpu.
*/
if (likely(slabp->nodeid == node))
return 0;
l3 = cachep->nodelists[node];
STATS_INC_NODEFREES(cachep);
if (l3->alien && l3->alien[nodeid]) {
alien = l3->alien[nodeid];
spin_lock(&alien->lock);
if (unlikely(alien->avail == alien->limit)) {
STATS_INC_ACOVERFLOW(cachep);
__drain_alien_cache(cachep, alien, nodeid);
}
ac_put_obj(cachep, alien, objp);
spin_unlock(&alien->lock);
} else {
spin_lock(&(cachep->nodelists[nodeid])->list_lock);
free_block(cachep, &objp, 1, nodeid);
spin_unlock(&(cachep->nodelists[nodeid])->list_lock);
}
return 1;
}
#endif
/*
* Allocates and initializes nodelists for a node on each slab cache, used for
* either memory or cpu hotplug. If memory is being hot-added, the kmem_list3
* will be allocated off-node since memory is not yet online for the new node.
* When hotplugging memory or a cpu, existing nodelists are not replaced if
* already in use.
*
* Must hold slab_mutex.
*/
static int init_cache_nodelists_node(int node)
{
struct kmem_cache *cachep;
struct kmem_list3 *l3;
const int memsize = sizeof(struct kmem_list3);
list_for_each_entry(cachep, &slab_caches, list) {
/*
* Set up the size64 kmemlist for cpu before we can
* begin anything. Make sure some other cpu on this
* node has not already allocated this
*/
if (!cachep->nodelists[node]) {
l3 = kmalloc_node(memsize, GFP_KERNEL, node);
if (!l3)
return -ENOMEM;
kmem_list3_init(l3);
l3->next_reap = jiffies + REAPTIMEOUT_LIST3 +
((unsigned long)cachep) % REAPTIMEOUT_LIST3;
/*
* The l3s don't come and go as CPUs come and
* go. slab_mutex is sufficient
* protection here.
*/
cachep->nodelists[node] = l3;
}
spin_lock_irq(&cachep->nodelists[node]->list_lock);
cachep->nodelists[node]->free_limit =
(1 + nr_cpus_node(node)) *
cachep->batchcount + cachep->num;
spin_unlock_irq(&cachep->nodelists[node]->list_lock);
}
return 0;
}
static void __cpuinit cpuup_canceled(long cpu)
{
struct kmem_cache *cachep;
struct kmem_list3 *l3 = NULL;
int node = cpu_to_mem(cpu);
const struct cpumask *mask = cpumask_of_node(node);
list_for_each_entry(cachep, &slab_caches, list) {
struct array_cache *nc;
struct array_cache *shared;
struct array_cache **alien;
/* cpu is dead; no one can alloc from it. */
nc = cachep->array[cpu];
cachep->array[cpu] = NULL;
l3 = cachep->nodelists[node];
if (!l3)
goto free_array_cache;
spin_lock_irq(&l3->list_lock);
/* Free limit for this kmem_list3 */
l3->free_limit -= cachep->batchcount;
if (nc)
free_block(cachep, nc->entry, nc->avail, node);
if (!cpumask_empty(mask)) {
spin_unlock_irq(&l3->list_lock);
goto free_array_cache;
}
shared = l3->shared;
if (shared) {
free_block(cachep, shared->entry,
shared->avail, node);
l3->shared = NULL;
}
alien = l3->alien;
l3->alien = NULL;
spin_unlock_irq(&l3->list_lock);
kfree(shared);
if (alien) {
drain_alien_cache(cachep, alien);
free_alien_cache(alien);
}
free_array_cache:
kfree(nc);
}
/*
* In the previous loop, all the objects were freed to
* the respective cache's slabs, now we can go ahead and
* shrink each nodelist to its limit.
*/
list_for_each_entry(cachep, &slab_caches, list) {
l3 = cachep->nodelists[node];
if (!l3)
continue;
drain_freelist(cachep, l3, l3->free_objects);
}
}
static int __cpuinit cpuup_prepare(long cpu)
{
struct kmem_cache *cachep;
struct kmem_list3 *l3 = NULL;
int node = cpu_to_mem(cpu);
int err;
/*
* We need to do this right in the beginning since
* alloc_arraycache's are going to use this list.
* kmalloc_node allows us to add the slab to the right
* kmem_list3 and not this cpu's kmem_list3
*/
err = init_cache_nodelists_node(node);
if (err < 0)
goto bad;
/*
* Now we can go ahead with allocating the shared arrays and
* array caches
*/
list_for_each_entry(cachep, &slab_caches, list) {
struct array_cache *nc;
struct array_cache *shared = NULL;
struct array_cache **alien = NULL;
nc = alloc_arraycache(node, cachep->limit,
cachep->batchcount, GFP_KERNEL);
if (!nc)
goto bad;
if (cachep->shared) {
shared = alloc_arraycache(node,
cachep->shared * cachep->batchcount,
0xbaadf00d, GFP_KERNEL);
if (!shared) {
kfree(nc);
goto bad;
}
}
if (use_alien_caches) {
alien = alloc_alien_cache(node, cachep->limit, GFP_KERNEL);
if (!alien) {
kfree(shared);
kfree(nc);
goto bad;
}
}
cachep->array[cpu] = nc;
l3 = cachep->nodelists[node];
BUG_ON(!l3);
spin_lock_irq(&l3->list_lock);
if (!l3->shared) {
/*
* We are serialised from CPU_DEAD or
* CPU_UP_CANCELLED by the cpucontrol lock
*/
l3->shared = shared;
shared = NULL;
}
#ifdef CONFIG_NUMA
if (!l3->alien) {
l3->alien = alien;
alien = NULL;
}
#endif
spin_unlock_irq(&l3->list_lock);
kfree(shared);
free_alien_cache(alien);
if (cachep->flags & SLAB_DEBUG_OBJECTS)
slab_set_debugobj_lock_classes_node(cachep, node);
}
init_node_lock_keys(node);
return 0;
bad:
cpuup_canceled(cpu);
return -ENOMEM;
}
static int __cpuinit cpuup_callback(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
long cpu = (long)hcpu;
int err = 0;
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
mutex_lock(&slab_mutex);
err = cpuup_prepare(cpu);
mutex_unlock(&slab_mutex);
break;
case CPU_ONLINE:
case CPU_ONLINE_FROZEN:
start_cpu_timer(cpu);
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
/*
* Shutdown cache reaper. Note that the slab_mutex is
* held so that if cache_reap() is invoked it cannot do
* anything expensive but will only modify reap_work
* and reschedule the timer.
*/
cancel_delayed_work_sync(&per_cpu(slab_reap_work, cpu));
/* Now the cache_reaper is guaranteed to be not running. */
per_cpu(slab_reap_work, cpu).work.func = NULL;
break;
case CPU_DOWN_FAILED:
case CPU_DOWN_FAILED_FROZEN:
start_cpu_timer(cpu);
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
/*
* Even if all the cpus of a node are down, we don't free the
* kmem_list3 of any cache. This to avoid a race between
* cpu_down, and a kmalloc allocation from another cpu for
* memory from the node of the cpu going down. The list3
* structure is usually allocated from kmem_cache_create() and
* gets destroyed at kmem_cache_destroy().
*/
/* fall through */
#endif
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
mutex_lock(&slab_mutex);
cpuup_canceled(cpu);
mutex_unlock(&slab_mutex);
break;
}
return notifier_from_errno(err);
}
static struct notifier_block __cpuinitdata cpucache_notifier = {
&cpuup_callback, NULL, 0
};
#if defined(CONFIG_NUMA) && defined(CONFIG_MEMORY_HOTPLUG)
/*
* Drains freelist for a node on each slab cache, used for memory hot-remove.
* Returns -EBUSY if all objects cannot be drained so that the node is not
* removed.
*
* Must hold slab_mutex.
*/
static int __meminit drain_cache_nodelists_node(int node)
{
struct kmem_cache *cachep;
int ret = 0;
list_for_each_entry(cachep, &slab_caches, list) {
struct kmem_list3 *l3;
l3 = cachep->nodelists[node];
if (!l3)
continue;
drain_freelist(cachep, l3, l3->free_objects);
if (!list_empty(&l3->slabs_full) ||
!list_empty(&l3->slabs_partial)) {
ret = -EBUSY;
break;
}
}
return ret;
}
static int __meminit slab_memory_callback(struct notifier_block *self,
unsigned long action, void *arg)
{
struct memory_notify *mnb = arg;
int ret = 0;
int nid;
nid = mnb->status_change_nid;
if (nid < 0)
goto out;
switch (action) {
case MEM_GOING_ONLINE:
mutex_lock(&slab_mutex);
ret = init_cache_nodelists_node(nid);
mutex_unlock(&slab_mutex);
break;
case MEM_GOING_OFFLINE:
mutex_lock(&slab_mutex);
ret = drain_cache_nodelists_node(nid);
mutex_unlock(&slab_mutex);
break;
case MEM_ONLINE:
case MEM_OFFLINE:
case MEM_CANCEL_ONLINE:
case MEM_CANCEL_OFFLINE:
break;
}
out:
return notifier_from_errno(ret);
}
#endif /* CONFIG_NUMA && CONFIG_MEMORY_HOTPLUG */
/*
* swap the static kmem_list3 with kmalloced memory
*/
static void __init init_list(struct kmem_cache *cachep, struct kmem_list3 *list,
int nodeid)
{
struct kmem_list3 *ptr;
ptr = kmalloc_node(sizeof(struct kmem_list3), GFP_NOWAIT, nodeid);
BUG_ON(!ptr);
memcpy(ptr, list, sizeof(struct kmem_list3));
/*
* Do not assume that spinlocks can be initialized via memcpy:
*/
spin_lock_init(&ptr->list_lock);
MAKE_ALL_LISTS(cachep, ptr, nodeid);
cachep->nodelists[nodeid] = ptr;
}
/*
* For setting up all the kmem_list3s for cache whose buffer_size is same as
* size of kmem_list3.
*/
static void __init set_up_list3s(struct kmem_cache *cachep, int index)
{
int node;
for_each_online_node(node) {
cachep->nodelists[node] = &initkmem_list3[index + node];
cachep->nodelists[node]->next_reap = jiffies +
REAPTIMEOUT_LIST3 +
((unsigned long)cachep) % REAPTIMEOUT_LIST3;
}
}
/*
* Initialisation. Called after the page allocator have been initialised and
* before smp_init().
*/
void __init kmem_cache_init(void)
{
size_t left_over;
struct cache_sizes *sizes;
struct cache_names *names;
int i;
int order;
int node;
if (num_possible_nodes() == 1)
use_alien_caches = 0;
for (i = 0; i < NUM_INIT_LISTS; i++) {
kmem_list3_init(&initkmem_list3[i]);
if (i < MAX_NUMNODES)
cache_cache.nodelists[i] = NULL;
}
set_up_list3s(&cache_cache, CACHE_CACHE);
/*
* Fragmentation resistance on low memory - only use bigger
* page orders on machines with more than 32MB of memory if
* not overridden on the command line.
*/
if (!slab_max_order_set && totalram_pages > (32 << 20) >> PAGE_SHIFT)
slab_max_order = SLAB_MAX_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 struct
* kmem_cache structures of all caches, except cache_cache itself:
* cache_cache is statically allocated.
* Initially an __init data area is used for the head array and the
* kmem_list3 structures, it's replaced with a kmalloc allocated
* array at the end of the bootstrap.
* 2) Create the first kmalloc cache.
* The struct kmem_cache 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) Replace the __init data for kmem_list3 for cache_cache and
* the other cache's with kmalloc allocated memory.
* 6) Resize the head arrays of the kmalloc caches to their final sizes.
*/
node = numa_mem_id();
/* 1) create the cache_cache */
INIT_LIST_HEAD(&slab_caches);
list_add(&cache_cache.list, &slab_caches);
cache_cache.colour_off = cache_line_size();
cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
cache_cache.nodelists[node] = &initkmem_list3[CACHE_CACHE + node];
/*
* struct kmem_cache size depends on nr_node_ids & nr_cpu_ids
*/
cache_cache.size = offsetof(struct kmem_cache, array[nr_cpu_ids]) +
nr_node_ids * sizeof(struct kmem_list3 *);
cache_cache.object_size = cache_cache.size;
cache_cache.size = ALIGN(cache_cache.size,
cache_line_size());
cache_cache.reciprocal_buffer_size =
reciprocal_value(cache_cache.size);
for (order = 0; order < MAX_ORDER; order++) {
cache_estimate(order, cache_cache.size,
cache_line_size(), 0, &left_over, &cache_cache.num);
if (cache_cache.num)
break;
}
BUG_ON(!cache_cache.num);
cache_cache.gfporder = order;
cache_cache.colour = left_over / cache_cache.colour_off;
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;
/*
* Initialize the caches that provide memory for the array cache and the
* kmem_list3 structures first. Without this, further allocations will
* bug.
*/
sizes[INDEX_AC].cs_cachep = __kmem_cache_create(names[INDEX_AC].name,
sizes[INDEX_AC].cs_size,
ARCH_KMALLOC_MINALIGN,
ARCH_KMALLOC_FLAGS|SLAB_PANIC,
NULL);
if (INDEX_AC != INDEX_L3) {
sizes[INDEX_L3].cs_cachep =
__kmem_cache_create(names[INDEX_L3].name,
sizes[INDEX_L3].cs_size,
ARCH_KMALLOC_MINALIGN,
ARCH_KMALLOC_FLAGS|SLAB_PANIC,
NULL);
}
slab_early_init = 0;
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.
*/
if (!sizes->cs_cachep) {
sizes->cs_cachep = __kmem_cache_create(names->name,
sizes->cs_size,
ARCH_KMALLOC_MINALIGN,
ARCH_KMALLOC_FLAGS|SLAB_PANIC,
NULL);
}
#ifdef CONFIG_ZONE_DMA
sizes->cs_dmacachep = __kmem_cache_create(
names->name_dma,
sizes->cs_size,
ARCH_KMALLOC_MINALIGN,
ARCH_KMALLOC_FLAGS|SLAB_CACHE_DMA|
SLAB_PANIC,
NULL);
#endif
sizes++;
names++;
}
/* 4) Replace the bootstrap head arrays */
{
struct array_cache *ptr;
ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
BUG_ON(cpu_cache_get(&cache_cache) != &initarray_cache.cache);
memcpy(ptr, cpu_cache_get(&cache_cache),
sizeof(struct arraycache_init));
/*
* Do not assume that spinlocks can be initialized via memcpy:
*/
spin_lock_init(&ptr->lock);
cache_cache.array[smp_processor_id()] = ptr;
ptr = kmalloc(sizeof(struct arraycache_init), GFP_NOWAIT);
BUG_ON(cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep)
!= &initarray_generic.cache);
memcpy(ptr, cpu_cache_get(malloc_sizes[INDEX_AC].cs_cachep),
sizeof(struct arraycache_init));
/*
* Do not assume that spinlocks can be initialized via memcpy:
*/
spin_lock_init(&ptr->lock);
malloc_sizes[INDEX_AC].cs_cachep->array[smp_processor_id()] =
ptr;
}
/* 5) Replace the bootstrap kmem_list3's */
{
int nid;
for_each_online_node(nid) {
init_list(&cache_cache, &initkmem_list3[CACHE_CACHE + nid], nid);
init_list(malloc_sizes[INDEX_AC].cs_cachep,
&initkmem_list3[SIZE_AC + nid], nid);
if (INDEX_AC != INDEX_L3) {
init_list(malloc_sizes[INDEX_L3].cs_cachep,
&initkmem_list3[SIZE_L3 + nid], nid);
}
}
}
slab_state = UP;
}
void __init kmem_cache_init_late(void)
{
struct kmem_cache *cachep;
slab_state = UP;
/* Annotate slab for lockdep -- annotate the malloc caches */
init_lock_keys();
/* 6) resize the head arrays to their final sizes */
mutex_lock(&slab_mutex);
list_for_each_entry(cachep, &slab_caches, list)
if (enable_cpucache(cachep, GFP_NOWAIT))
BUG();
mutex_unlock(&slab_mutex);
/* Done! */
slab_state = FULL;
/*
* Register a cpu startup notifier callback that initializes
* cpu_cache_get for all new cpus
*/
register_cpu_notifier(&cpucache_notifier);
#ifdef CONFIG_NUMA
/*
* Register a memory hotplug callback that initializes and frees
* nodelists.
*/
hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
#endif
/*
* 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 the page allocator
*/
for_each_online_cpu(cpu)
start_cpu_timer(cpu);
/* Done! */
slab_state = FULL;
return 0;
}
__initcall(cpucache_init);
static noinline void
slab_out_of_memory(struct kmem_cache *cachep, gfp_t gfpflags, int nodeid)
{
struct kmem_list3 *l3;
struct slab *slabp;
unsigned long flags;
int node;
printk(KERN_WARNING
"SLAB: Unable to allocate memory on node %d (gfp=0x%x)\n",
nodeid, gfpflags);
printk(KERN_WARNING " cache: %s, object size: %d, order: %d\n",
cachep->name, cachep->size, cachep->gfporder);
for_each_online_node(node) {
unsigned long active_objs = 0, num_objs = 0, free_objects = 0;
unsigned long active_slabs = 0, num_slabs = 0;
l3 = cachep->nodelists[node];
if (!l3)
continue;
spin_lock_irqsave(&l3->list_lock, flags);
list_for_each_entry(slabp, &l3->slabs_full, list) {
active_objs += cachep->num;
active_slabs++;
}
list_for_each_entry(slabp, &l3->slabs_partial, list) {
active_objs += slabp->inuse;
active_slabs++;
}
list_for_each_entry(slabp, &l3->slabs_free, list)
num_slabs++;
free_objects += l3->free_objects;
spin_unlock_irqrestore(&l3->list_lock, flags);
num_slabs += active_slabs;
num_objs = num_slabs * cachep->num;
printk(KERN_WARNING
" node %d: slabs: %ld/%ld, objs: %ld/%ld, free: %ld\n",
node, active_slabs, num_slabs, active_objs, num_objs,
free_objects);
}
}
/*
* 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(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{
struct page *page;
int nr_pages;
int i;
#ifndef CONFIG_MMU
/*
* Nommu uses slab's for process anonymous memory allocations, and thus
* requires __GFP_COMP to properly refcount higher order allocations
*/
flags |= __GFP_COMP;
#endif
flags |= cachep->allocflags;
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
flags |= __GFP_RECLAIMABLE;
page = alloc_pages_exact_node(nodeid, flags | __GFP_NOTRACK, cachep->gfporder);
if (!page) {
if (!(flags & __GFP_NOWARN) && printk_ratelimit())
slab_out_of_memory(cachep, flags, nodeid);
return NULL;
}
/* Record if ALLOC_NO_WATERMARKS was set when allocating the slab */
if (unlikely(page->pfmemalloc))
pfmemalloc_active = true;
nr_pages = (1 << cachep->gfporder);
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
add_zone_page_state(page_zone(page),
NR_SLAB_RECLAIMABLE, nr_pages);
else
add_zone_page_state(page_zone(page),
NR_SLAB_UNRECLAIMABLE, nr_pages);
for (i = 0; i < nr_pages; i++) {
__SetPageSlab(page + i);
if (page->pfmemalloc)
SetPageSlabPfmemalloc(page + i);
}
if (kmemcheck_enabled && !(cachep->flags & SLAB_NOTRACK)) {
kmemcheck_alloc_shadow(page, cachep->gfporder, flags, nodeid);
if (cachep->ctor)
kmemcheck_mark_uninitialized_pages(page, nr_pages);
else
kmemcheck_mark_unallocated_pages(page, nr_pages);
}
return page_address(page);
}
/*
* Interface to system's page release.
*/
static void kmem_freepages(struct kmem_cache *cachep, void *addr)
{
unsigned long i = (1 << cachep->gfporder);
struct page *page = virt_to_page(addr);
const unsigned long nr_freed = i;
kmemcheck_free_shadow(page, cachep->gfporder);
if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
sub_zone_page_state(page_zone(page),
NR_SLAB_RECLAIMABLE, nr_freed);
else
sub_zone_page_state(page_zone(page),
NR_SLAB_UNRECLAIMABLE, nr_freed);
while (i--) {
BUG_ON(!PageSlab(page));
__ClearPageSlabPfmemalloc(page);
__ClearPageSlab(page);
page++;
}
if (current->reclaim_state)
current->reclaim_state->reclaimed_slab += nr_freed;
free_pages((unsigned long)addr, cachep->gfporder);
}
static void kmem_rcu_free(struct rcu_head *head)
{
struct slab_rcu *slab_rcu = (struct slab_rcu *)head;
struct kmem_cache *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(struct kmem_cache *cachep, unsigned long *addr,
unsigned long caller)
{
int size = cachep->object_size;
addr = (unsigned long *)&((char *)addr)[obj_offset(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(struct kmem_cache *cachep, void *addr, unsigned char val)
{
int size = cachep->object_size;
addr = &((char *)addr)[obj_offset(cachep)];
memset(addr, val, size);
*(unsigned char *)(addr + size - 1) = POISON_END;
}
static void dump_line(char *data, int offset, int limit)
{
int i;
unsigned char error = 0;
int bad_count = 0;
printk(KERN_ERR "%03x: ", offset);
for (i = 0; i < limit; i++) {
if (data[offset + i] != POISON_FREE) {
error = data[offset + i];
bad_count++;
}
}
print_hex_dump(KERN_CONT, "", 0, 16, 1,
&data[offset], limit, 1);
if (bad_count == 1) {
error ^= POISON_FREE;
if (!(error & (error - 1))) {
printk(KERN_ERR "Single bit error detected. Probably "
"bad RAM.\n");
#ifdef CONFIG_X86
printk(KERN_ERR "Run memtest86+ or a similar memory "
"test tool.\n");
#else
printk(KERN_ERR "Run a memory test tool.\n");
#endif
}
}
}
#endif
#if DEBUG
static void print_objinfo(struct kmem_cache *cachep, void *objp, int lines)
{
int i, size;
char *realobj;
if (cachep->flags & SLAB_RED_ZONE) {
printk(KERN_ERR "Redzone: 0x%llx/0x%llx.\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_offset(cachep);
size = cachep->object_size;
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(struct kmem_cache *cachep, void *objp)
{
char *realobj;
int size, i;
int lines = 0;
realobj = (char *)objp + obj_offset(cachep);
size = cachep->object_size;
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 (%s): %s start=%p, len=%d\n",
print_tainted(), cachep->name, 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 = virt_to_slab(objp);
unsigned int objnr;
objnr = obj_to_index(cachep, slabp, objp);
if (objnr) {
objp = index_to_obj(cachep, slabp, objnr - 1);
realobj = (char *)objp + obj_offset(cachep);
printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
realobj, size);
print_objinfo(cachep, objp, 2);
}
if (objnr + 1 < cachep->num) {
objp = index_to_obj(cachep, slabp, objnr + 1);
realobj = (char *)objp + obj_offset(cachep);
printk(KERN_ERR "Next obj: start=%p, len=%d\n",
realobj, size);
print_objinfo(cachep, objp, 2);
}
}
}
#endif
#if DEBUG
static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
{
int i;
for (i = 0; i < cachep->num; i++) {
void *objp = index_to_obj(cachep, slabp, i);
if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
if (cachep->size % PAGE_SIZE == 0 &&
OFF_SLAB(cachep))
kernel_map_pages(virt_to_page(objp),
cachep->size / 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");
}
}
}
#else
static void slab_destroy_debugcheck(struct kmem_cache *cachep, struct slab *slabp)
{
}
#endif
/**
* slab_destroy - destroy and release all objects in a slab
* @cachep: cache pointer being destroyed
* @slabp: slab pointer being destroyed
*
* 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(struct kmem_cache *cachep, struct slab *slabp)
{
void *addr = slabp->s_mem - slabp->colouroff;
slab_destroy_debugcheck(cachep, slabp);
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);
}
}
static void __kmem_cache_destroy(struct kmem_cache *cachep)
{
int i;
struct kmem_list3 *l3;
for_each_online_cpu(i)
kfree(cachep->array[i]);
/* NUMA: free the list3 structures */
for_each_online_node(i) {
l3 = cachep->nodelists[i];
if (l3) {
kfree(l3->shared);
free_alien_cache(l3->alien);
kfree(l3);
}
}
kmem_cache_free(&cache_cache, cachep);
}
/**
* calculate_slab_order - calculate size (page order) of slabs
* @cachep: pointer to the cache that is being created
* @size: size of objects to be created in this cache.
* @align: required alignment for the objects.
* @flags: slab allocation flags
*
* Also calculates the number of objects per slab.
*
* This could be made much more intelligent. For now, try to avoid using
* high order pages for slabs. When the gfp() functions are more friendly
* towards high-order requests, this should be changed.
*/
static size_t calculate_slab_order(struct kmem_cache *cachep,
size_t size, size_t align, unsigned long flags)
{
unsigned long offslab_limit;
size_t left_over = 0;
int gfporder;
for (gfporder = 0; gfporder <= KMALLOC_MAX_ORDER; gfporder++) {
unsigned int num;
size_t remainder;
cache_estimate(gfporder, size, align, flags, &remainder, &num);
if (!num)
continue;
if (flags & CFLGS_OFF_SLAB) {
/*
* Max number of objs-per-slab for caches which
* use off-slab slabs. Needed to avoid a possible
* looping condition in cache_grow().
*/
offslab_limit = size - sizeof(struct slab);
offslab_limit /= sizeof(kmem_bufctl_t);
if (num > offslab_limit)
break;
}
/* Found something acceptable - save it away */
cachep->num = num;
cachep->gfporder = gfporder;
left_over = remainder;
/*
* 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.
*/
if (flags & SLAB_RECLAIM_ACCOUNT)
break;
/*
* Large number of objects is good, but very large slabs are
* currently bad for the gfp()s.
*/
if (gfporder >= slab_max_order)
break;
/*
* Acceptable internal fragmentation?
*/
if (left_over * 8 <= (PAGE_SIZE << gfporder))
break;
}
return left_over;
}
static int __init_refok setup_cpu_cache(struct kmem_cache *cachep, gfp_t gfp)
{
if (slab_state >= FULL)
return enable_cpucache(cachep, gfp);
if (slab_state == DOWN) {
/*
* 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;
/*
* If the cache that's used by kmalloc(sizeof(kmem_list3)) is
* the first cache, then we need to set up all its list3s,
* otherwise the creation of further caches will BUG().
*/
set_up_list3s(cachep, SIZE_AC);
if (INDEX_AC == INDEX_L3)
slab_state = PARTIAL_L3;
else
slab_state = PARTIAL_ARRAYCACHE;
} else {
cachep->array[smp_processor_id()] =
kmalloc(sizeof(struct arraycache_init), gfp);
if (slab_state == PARTIAL_ARRAYCACHE) {
set_up_list3s(cachep, SIZE_L3);
slab_state = PARTIAL_L3;
} else {
int node;
for_each_online_node(node) {
cachep->nodelists[node] =
kmalloc_node(sizeof(struct kmem_list3),
gfp, node);
BUG_ON(!cachep->nodelists[node]);
kmem_list3_init(cachep->nodelists[node]);
}
}
}
cachep->nodelists[numa_mem_id()]->next_reap =
jiffies + REAPTIMEOUT_LIST3 +
((unsigned long)cachep) % REAPTIMEOUT_LIST3;
cpu_cache_get(cachep)->avail = 0;
cpu_cache_get(cachep)->limit = BOOT_CPUCACHE_ENTRIES;
cpu_cache_get(cachep)->batchcount = 1;
cpu_cache_get(cachep)->touched = 0;
cachep->batchcount = 1;
cachep->limit = BOOT_CPUCACHE_ENTRIES;
return 0;
}
/**
* __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.
*
* 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.
*
* @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_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.
*/
struct kmem_cache *
__kmem_cache_create (const char *name, size_t size, size_t align,
unsigned long flags, void (*ctor)(void *))
{
size_t left_over, slab_size, ralign;
struct kmem_cache *cachep = NULL;
gfp_t gfp;
#if DEBUG
#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 + REDZONE_ALIGN +
2 * sizeof(unsigned long long)))
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
/*
* Always checks flags, a caller might be expecting debug support which
* isn't available.
*/
BUG_ON(flags & ~CREATE_MASK);
/*
* 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 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;
}
/*
* Redzoning and user store require word alignment or possibly larger.
* Note this will be overridden by architecture or caller mandated
* alignment if either is greater than BYTES_PER_WORD.
*/
if (flags & SLAB_STORE_USER)
ralign = BYTES_PER_WORD;
if (flags & SLAB_RED_ZONE) {
ralign = REDZONE_ALIGN;
/* If redzoning, ensure that the second redzone is suitably
* aligned, by adjusting the object size accordingly. */
size += REDZONE_ALIGN - 1;
size &= ~(REDZONE_ALIGN - 1);
}
/* 2) arch mandated alignment */
if (ralign < ARCH_SLAB_MINALIGN) {
ralign = ARCH_SLAB_MINALIGN;
}
/* 3) caller mandated alignment */
if (ralign < align) {
ralign = align;
}
/* disable debug if necessary */
if (ralign > __alignof__(unsigned long long))
flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
/*
* 4) Store it.
*/
align = ralign;
if (slab_is_available())
gfp = GFP_KERNEL;
else
gfp = GFP_NOWAIT;
/* Get cache's description obj. */
cachep = kmem_cache_zalloc(&cache_cache, gfp);
if (!cachep)
return NULL;
cachep->nodelists = (struct kmem_list3 **)&cachep->array[nr_cpu_ids];
cachep->object_size = size;
cachep->align = align;
#if DEBUG
/*
* Both debugging options require word-alignment which is calculated
* into align above.
*/
if (flags & SLAB_RED_ZONE) {
/* add space for red zone words */
cachep->obj_offset += sizeof(unsigned long long);
size += 2 * sizeof(unsigned long long);
}
if (flags & SLAB_STORE_USER) {
/* user store requires one word storage behind the end of
* the real object. But if the second red zone needs to be
* aligned to 64 bits, we must allow that much space.
*/
if (flags & SLAB_RED_ZONE)
size += REDZONE_ALIGN;
else
size += BYTES_PER_WORD;
}
#if FORCED_DEBUG && defined(CONFIG_DEBUG_PAGEALLOC)
if (size >= malloc_sizes[INDEX_L3 + 1].cs_size
&& cachep->object_size > cache_line_size() && ALIGN(size, align) < PAGE_SIZE) {
cachep->obj_offset += PAGE_SIZE - ALIGN(size, align);
size = PAGE_SIZE;
}
#endif
#endif
/*
* Determine if the slab management is 'on' or 'off' slab.
* (bootstrapping cannot cope with offslab caches so don't do
* it too early on. Always use on-slab management when
* SLAB_NOLEAKTRACE to avoid recursive calls into kmemleak)
*/
if ((size >= (PAGE_SIZE >> 3)) && !slab_early_init &&
!(flags & SLAB_NOLEAKTRACE))
/*
* 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);
left_over = calculate_slab_order(cachep, size, align, flags);
if (!cachep->num) {
printk(KERN_ERR
"kmem_cache_create: couldn't create cache %s.\n", name);
kmem_cache_free(&cache_cache, cachep);
return NULL;
}
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);
#ifdef CONFIG_PAGE_POISONING
/* If we're going to use the generic kernel_map_pages()
* poisoning, then it's going to smash the contents of
* the redzone and userword anyhow, so switch them off.
*/
if (size % PAGE_SIZE == 0 && flags & SLAB_POISON)
flags &= ~(SLAB_RED_ZONE | SLAB_STORE_USER);
#endif
}
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->allocflags = 0;
if (CONFIG_ZONE_DMA_FLAG && (flags & SLAB_CACHE_DMA))
cachep->allocflags |= GFP_DMA;
cachep->size = size;
cachep->reciprocal_buffer_size = reciprocal_value(size);
if (flags & CFLGS_OFF_SLAB) {
cachep->slabp_cache = kmem_find_general_cachep(slab_size, 0u);
/*
* This is a possibility for one of the malloc_sizes caches.
* But since we go off slab only for object size greater than
* PAGE_SIZE/8, and malloc_sizes gets created in ascending order,
* this should not happen at all.
* But leave a BUG_ON for some lucky dude.
*/
BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache));
}
cachep->ctor = ctor;
cachep->name = name;
if (setup_cpu_cache(cachep, gfp)) {
__kmem_cache_destroy(cachep);
return NULL;
}
if (flags & SLAB_DEBUG_OBJECTS) {
/*
* Would deadlock through slab_destroy()->call_rcu()->
* debug_object_activate()->kmem_cache_alloc().
*/
WARN_ON_ONCE(flags & SLAB_DESTROY_BY_RCU);
slab_set_debugobj_lock_classes(cachep);
}
/* cache setup completed, link it into the list */
list_add(&cachep->list, &slab_caches);
return cachep;
}
#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(struct kmem_cache *cachep)
{
#ifdef CONFIG_SMP
check_irq_off();
assert_spin_locked(&cachep->nodelists[numa_mem_id()]->list_lock);
#endif
}
static void check_spinlock_acquired_node(struct kmem_cache *cachep, int node)
{
#ifdef CONFIG_SMP
check_irq_off();
assert_spin_locked(&cachep->nodelists[node]->list_lock);
#endif
}
#else
#define check_irq_off() do { } while(0)
#define check_irq_on() do { } while(0)
#define check_spinlock_acquired(x) do { } while(0)
#define check_spinlock_acquired_node(x, y) do { } while(0)
#endif
static void drain_array(struct kmem_cache *cachep, struct kmem_list3 *l3,
struct array_cache *ac,
int force, int node);
static void do_drain(void *arg)
{
struct kmem_cache *cachep = arg;
struct array_cache *ac;
int node = numa_mem_id();
check_irq_off();
ac = cpu_cache_get(cachep);
spin_lock(&cachep->nodelists[node]->list_lock);
free_block(cachep, ac->entry, ac->avail, node);
spin_unlock(&cachep->nodelists[node]->list_lock);
ac->avail = 0;
}
static void drain_cpu_caches(struct kmem_cache *cachep)
{
struct kmem_list3 *l3;
int node;
on_each_cpu(do_drain, cachep, 1);
check_irq_on();
for_each_online_node(node) {
l3 = cachep->nodelists[node];
if (l3 && l3->alien)
drain_alien_cache(cachep, l3->alien);
}
for_each_online_node(node) {
l3 = cachep->nodelists[node];
if (l3)
drain_array(cachep, l3, l3->shared, 1, node);
}
}
/*
* Remove slabs from the list of free slabs.
* Specify the number of slabs to drain in tofree.
*
* Returns the actual number of slabs released.
*/
static int drain_freelist(struct kmem_cache *cache,
struct kmem_list3 *l3, int tofree)
{
struct list_head *p;
int nr_freed;
struct slab *slabp;
nr_freed = 0;
while (nr_freed < tofree && !list_empty(&l3->slabs_free)) {
spin_lock_irq(&l3->list_lock);
p = l3->slabs_free.prev;
if (p == &l3->slabs_free) {
spin_unlock_irq(&l3->list_lock);
goto out;
}
slabp = list_entry(p, struct slab, list);
#if DEBUG
BUG_ON(slabp->inuse);
#endif
list_del(&slabp->list);
/*
* Safe to drop the lock. The slab is no longer linked
* to the cache.
*/
l3->free_objects -= cache->num;
spin_unlock_irq(&l3->list_lock);
slab_destroy(cache, slabp);
nr_freed++;
}
out:
return nr_freed;
}
/* Called with slab_mutex held to protect against cpu hotplug */
static int __cache_shrink(struct kmem_cache *cachep)
{
int ret = 0, i = 0;
struct kmem_list3 *l3;
drain_cpu_caches(cachep);
check_irq_on();
for_each_online_node(i) {
l3 = cachep->nodelists[i];
if (!l3)
continue;
drain_freelist(cachep, l3, l3->free_objects);
ret += !list_empty(&l3->slabs_full) ||
!list_empty(&l3->slabs_partial);
}
return (ret ? 1 : 0);
}
/**
* 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(struct kmem_cache *cachep)
{
int ret;
BUG_ON(!cachep || in_interrupt());
get_online_cpus();
mutex_lock(&slab_mutex);
ret = __cache_shrink(cachep);
mutex_unlock(&slab_mutex);
put_online_cpus();
return ret;
}
EXPORT_SYMBOL(kmem_cache_shrink);
/**
* kmem_cache_destroy - delete a cache
* @cachep: the cache to destroy
*
* Remove a &struct kmem_cache object from the slab cache.
*
* 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 no one will allocate memory from the cache
* during the kmem_cache_destroy().
*/
void kmem_cache_destroy(struct kmem_cache *cachep)
{
BUG_ON(!cachep || in_interrupt());
/* Find the cache in the chain of caches. */
get_online_cpus();
mutex_lock(&slab_mutex);
/*
* the chain is never empty, cache_cache is never destroyed
*/
list_del(&cachep->list);
if (__cache_shrink(cachep)) {
slab_error(cachep, "Can't free all objects");
list_add(&cachep->list, &slab_caches);
mutex_unlock(&slab_mutex);
put_online_cpus();
return;
}
if (unlikely(cachep->flags & SLAB_DESTROY_BY_RCU))
rcu_barrier();
__kmem_cache_destroy(cachep);
mutex_unlock(&slab_mutex);
put_online_cpus();
}
EXPORT_SYMBOL(kmem_cache_destroy);
/*
* Get the memory for a slab management obj.
* For a slab cache when the slab descriptor is off-slab, slab descriptors
* always come from malloc_sizes caches. The slab descriptor cannot
* come from the same cache which is getting created because,
* when we are searching for an appropriate cache for these
* descriptors in kmem_cache_create, we search through the malloc_sizes array.
* If we are creating a malloc_sizes cache here it would not be visible to
* kmem_find_general_cachep till the initialization is complete.
* Hence we cannot have slabp_cache same as the original cache.
*/
static struct slab *alloc_slabmgmt(struct kmem_cache *cachep, void *objp,
int colour_off, gfp_t local_flags,
int nodeid)
{
struct slab *slabp;
if (OFF_SLAB(cachep)) {
/* Slab management obj is off-slab. */
slabp = kmem_cache_alloc_node(cachep->slabp_cache,
local_flags, nodeid);
/*
* If the first object in the slab is leaked (it's allocated
* but no one has a reference to it), we want to make sure
* kmemleak does not treat the ->s_mem pointer as a reference
* to the object. Otherwise we will not report the leak.
*/
kmemleak_scan_area(&slabp->list, sizeof(struct list_head),
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;
slabp->nodeid = nodeid;
slabp->free = 0;
return slabp;
}
static inline kmem_bufctl_t *slab_bufctl(struct slab *slabp)
{
return (kmem_bufctl_t *) (slabp + 1);
}
static void cache_init_objs(struct kmem_cache *cachep,
struct slab *slabp)
{
int i;
for (i = 0; i < cachep->num; i++) {
void *objp = index_to_obj(cachep, slabp, 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_offset(cachep));
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->size % PAGE_SIZE) == 0 &&
OFF_SLAB(cachep) && cachep->flags & SLAB_POISON)
kernel_map_pages(virt_to_page(objp),
cachep->size / PAGE_SIZE, 0);
#else
if (cachep->ctor)
cachep->ctor(objp);
#endif
slab_bufctl(slabp)[i] = i + 1;
}
slab_bufctl(slabp)[i - 1] = BUFCTL_END;
}
static void kmem_flagcheck(struct kmem_cache *cachep, gfp_t flags)
{
if (CONFIG_ZONE_DMA_FLAG) {
if (flags & GFP_DMA)
BUG_ON(!(cachep->allocflags & GFP_DMA));
else
BUG_ON(cachep->allocflags & GFP_DMA);
}
}
static void *slab_get_obj(struct kmem_cache *cachep, struct slab *slabp,
int nodeid)
{
void *objp = index_to_obj(cachep, slabp, slabp->free);
kmem_bufctl_t next;
slabp->inuse++;
next = slab_bufctl(slabp)[slabp->free];
#if DEBUG
slab_bufctl(slabp)[slabp->free] = BUFCTL_FREE;
WARN_ON(slabp->nodeid != nodeid);
#endif
slabp->free = next;
return objp;
}
static void slab_put_obj(struct kmem_cache *cachep, struct slab *slabp,
void *objp, int nodeid)
{
unsigned int objnr = obj_to_index(cachep, slabp, objp);
#if DEBUG
/* Verify that the slab belongs to the intended node */
WARN_ON(slabp->nodeid != nodeid);
if (slab_bufctl(slabp)[objnr] + 1 <= SLAB_LIMIT + 1) {
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;
slabp->inuse--;
}
/*
* Map pages beginning at addr to the given cache and slab. This is required
* for the slab allocator to be able to lookup the cache and slab of a
* virtual address for kfree, ksize, and slab debugging.
*/
static void slab_map_pages(struct kmem_cache *cache, struct slab *slab,
void *addr)
{
int nr_pages;
struct page *page;
page = virt_to_page(addr);
nr_pages = 1;
if (likely(!PageCompound(page)))
nr_pages <<= cache->gfporder;
do {
page->slab_cache = cache;
page->slab_page = slab;
page++;
} while (--nr_pages);
}
/*
* 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(struct kmem_cache *cachep,
gfp_t flags, int nodeid, void *objp)
{
struct slab *slabp;
size_t offset;
gfp_t local_flags;
struct kmem_list3 *l3;
/*
* Be lazy and only check for valid flags here, keeping it out of the
* critical path in kmem_cache_alloc().
*/
BUG_ON(flags & GFP_SLAB_BUG_MASK);
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
/* Take the l3 list lock to change the colour_next on this node */
check_irq_off();
l3 = cachep->nodelists[nodeid];
spin_lock(&l3->list_lock);
/* Get colour for the slab, and cal the next value. */
offset = l3->colour_next;
l3->colour_next++;
if (l3->colour_next >= cachep->colour)
l3->colour_next = 0;
spin_unlock(&l3->list_lock);
offset *= cachep->colour_off;
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. Attempt to allocate a physical page from
* 'nodeid'.
*/
if (!objp)
objp = kmem_getpages(cachep, local_flags, nodeid);
if (!objp)
goto failed;
/* Get slab management. */
slabp = alloc_slabmgmt(cachep, objp, offset,
local_flags & ~GFP_CONSTRAINT_MASK, nodeid);
if (!slabp)
goto opps1;
slab_map_pages(cachep, slabp, objp);
cache_init_objs(cachep, slabp);
if (local_flags & __GFP_WAIT)
local_irq_disable();
check_irq_off();
spin_lock(&l3->list_lock);
/* Make slab active. */
list_add_tail(&slabp->list, &(l3->slabs_free));
STATS_INC_GROWN(cachep);
l3->free_objects += cachep->num;
spin_unlock(&l3->list_lock);
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
*/
static void kfree_debugcheck(const void *objp)
{
if (!virt_addr_valid(objp)) {
printk(KERN_ERR "kfree_debugcheck: out of range ptr %lxh.\n",
(unsigned long)objp);
BUG();
}
}
static inline void verify_redzone_free(struct kmem_cache *cache, void *obj)
{
unsigned long long redzone1, redzone2;
redzone1 = *dbg_redzone1(cache, obj);
redzone2 = *dbg_redzone2(cache, obj);
/*
* Redzone is ok.
*/
if (redzone1 == RED_ACTIVE && redzone2 == RED_ACTIVE)
return;
if (redzone1 == RED_INACTIVE && redzone2 == RED_INACTIVE)
slab_error(cache, "double free detected");
else
slab_error(cache, "memory outside object was overwritten");
printk(KERN_ERR "%p: redzone 1:0x%llx, redzone 2:0x%llx.\n",
obj, redzone1, redzone2);
}
static void *cache_free_debugcheck(struct kmem_cache *cachep, void *objp,
void *caller)
{
struct page *page;
unsigned int objnr;
struct slab *slabp;
BUG_ON(virt_to_cache(objp) != cachep);
objp -= obj_offset(cachep);
kfree_debugcheck(objp);
page = virt_to_head_page(objp);
slabp = page->slab_page;
if (cachep->flags & SLAB_RED_ZONE) {
verify_redzone_free(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 = obj_to_index(cachep, slabp, objp);
BUG_ON(objnr >= cachep->num);
BUG_ON(objp != index_to_obj(cachep, slabp, objnr));
#ifdef CONFIG_DEBUG_SLAB_LEAK
slab_bufctl(slabp)[objnr] = BUFCTL_FREE;
#endif
if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
if ((cachep->size % PAGE_SIZE)==0 && OFF_SLAB(cachep)) {
store_stackinfo(cachep, objp, (unsigned long)caller);
kernel_map_pages(virt_to_page(objp),
cachep->size / PAGE_SIZE, 0);
} else {
poison_obj(cachep, objp, POISON_FREE);
}
#else
poison_obj(cachep, objp, POISON_FREE);
#endif
}
return objp;
}
static void check_slabp(struct kmem_cache *cachep, struct slab *slabp)
{
kmem_bufctl_t i;
int entries = 0;
/* 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). Tainted(%s). Hexdump:\n",
cachep->name, cachep->num, slabp, slabp->inuse,
print_tainted());
print_hex_dump(KERN_ERR, "", DUMP_PREFIX_OFFSET, 16, 1, slabp,
sizeof(*slabp) + cachep->num * sizeof(kmem_bufctl_t),
1);
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(struct kmem_cache *cachep, gfp_t flags,
bool force_refill)
{
int batchcount;
struct kmem_list3 *l3;
struct array_cache *ac;
int node;
check_irq_off();
node = numa_mem_id();
if (unlikely(force_refill))
goto force_grow;
retry:
ac = cpu_cache_get(cachep);
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 = cachep->nodelists[node];
BUG_ON(ac->avail > 0 || !l3);
spin_lock(&l3->list_lock);
/* See if we can refill from the shared array */
if (l3->shared && transfer_objects(ac, l3->shared, batchcount)) {
l3->shared->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);
/*
* The slab was either on partial or free list so
* there must be at least one object available for
* allocation.
*/
BUG_ON(slabp->inuse >= cachep->num);
while (slabp->inuse < cachep->num && batchcount--) {
STATS_INC_ALLOCED(cachep);
STATS_INC_ACTIVE(cachep);
STATS_SET_HIGH(cachep);
ac_put_obj(cachep, ac, slab_get_obj(cachep, slabp,
node));
}
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(&l3->list_lock);
if (unlikely(!ac->avail)) {
int x;
force_grow:
x = cache_grow(cachep, flags | GFP_THISNODE, node, NULL);
/* cache_grow can reenable interrupts, then ac could change. */
ac = cpu_cache_get(cachep);
/* no objects in sight? abort */
if (!x && (ac->avail == 0 || force_refill))
return NULL;
if (!ac->avail) /* objects refilled by interrupt? */
goto retry;
}
ac->touched = 1;
return ac_get_obj(cachep, ac, flags, force_refill);
}
static inline void cache_alloc_debugcheck_before(struct kmem_cache *cachep,
gfp_t flags)
{
might_sleep_if(flags & __GFP_WAIT);
#if DEBUG
kmem_flagcheck(cachep, flags);
#endif
}
#if DEBUG
static void *cache_alloc_debugcheck_after(struct kmem_cache *cachep,
gfp_t flags, void *objp, void *caller)
{
if (!objp)
return objp;
if (cachep->flags & SLAB_POISON) {
#ifdef CONFIG_DEBUG_PAGEALLOC
if ((cachep->size % PAGE_SIZE) == 0 && OFF_SLAB(cachep))
kernel_map_pages(virt_to_page(objp),
cachep->size / 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%llx, redzone 2:0x%llx\n",
objp, *dbg_redzone1(cachep, objp),
*dbg_redzone2(cachep, objp));
}
*dbg_redzone1(cachep, objp) = RED_ACTIVE;
*dbg_redzone2(cachep, objp) = RED_ACTIVE;
}
#ifdef CONFIG_DEBUG_SLAB_LEAK
{
struct slab *slabp;
unsigned objnr;
slabp = virt_to_head_page(objp)->slab_page;
objnr = (unsigned)(objp - slabp->s_mem) / cachep->size;
slab_bufctl(slabp)[objnr] = BUFCTL_ACTIVE;
}
#endif
objp += obj_offset(cachep);
if (cachep->ctor && cachep->flags & SLAB_POISON)
cachep->ctor(objp);
if (ARCH_SLAB_MINALIGN &&
((unsigned long)objp & (ARCH_SLAB_MINALIGN-1))) {
printk(KERN_ERR "0x%p: not aligned to ARCH_SLAB_MINALIGN=%d\n",
objp, (int)ARCH_SLAB_MINALIGN);
}
return objp;
}
#else
#define cache_alloc_debugcheck_after(a,b,objp,d) (objp)
#endif
static bool slab_should_failslab(struct kmem_cache *cachep, gfp_t flags)
{
if (cachep == &cache_cache)
return false;
return should_failslab(cachep->object_size, flags, cachep->flags);
}
static inline void *____cache_alloc(struct kmem_cache *cachep, gfp_t flags)
{
void *objp;
struct array_cache *ac;
bool force_refill = false;
check_irq_off();
ac = cpu_cache_get(cachep);
if (likely(ac->avail)) {
ac->touched = 1;
objp = ac_get_obj(cachep, ac, flags, false);
/*
* Allow for the possibility all avail objects are not allowed
* by the current flags
*/
if (objp) {
STATS_INC_ALLOCHIT(cachep);
goto out;
}
force_refill = true;
}
STATS_INC_ALLOCMISS(cachep);
objp = cache_alloc_refill(cachep, flags, force_refill);
/*
* the 'ac' may be updated by cache_alloc_refill(),
* and kmemleak_erase() requires its correct value.
*/
ac = cpu_cache_get(cachep);
out:
/*
* To avoid a false negative, if an object that is in one of the
* per-CPU caches is leaked, we need to make sure kmemleak doesn't
* treat the array pointers as a reference to the object.
*/
if (objp)
kmemleak_erase(&ac->entry[ac->avail]);
return objp;
}
#ifdef CONFIG_NUMA
/*
* Try allocating on another node if PF_SPREAD_SLAB|PF_MEMPOLICY.
*
* If we are in_interrupt, then process context, including cpusets and
* mempolicy, may not apply and should not be used for allocation policy.
*/
static void *alternate_node_alloc(struct kmem_cache *cachep, gfp_t flags)
{
int nid_alloc, nid_here;
if (in_interrupt() || (flags & __GFP_THISNODE))
return NULL;
nid_alloc = nid_here = numa_mem_id();
if (cpuset_do_slab_mem_spread() && (cachep->flags & SLAB_MEM_SPREAD))
nid_alloc = cpuset_slab_spread_node();
else if (current->mempolicy)
nid_alloc = slab_node();
if (nid_alloc != nid_here)
return ____cache_alloc_node(cachep, flags, nid_alloc);
return NULL;
}
/*
* Fallback function if there was no memory available and no objects on a
* certain node and fall back is permitted. First we scan all the
* available nodelists for available objects. If that fails then we
* perform an allocation without specifying a node. This allows the page
* allocator to do its reclaim / fallback magic. We then insert the
* slab into the proper nodelist and then allocate from it.
*/
static void *fallback_alloc(struct kmem_cache *cache, gfp_t flags)
{
struct zonelist *zonelist;
gfp_t local_flags;
struct zoneref *z;
struct zone *zone;
enum zone_type high_zoneidx = gfp_zone(flags);
void *obj = NULL;
int nid;
unsigned int cpuset_mems_cookie;
if (flags & __GFP_THISNODE)
return NULL;
local_flags = flags & (GFP_CONSTRAINT_MASK|GFP_RECLAIM_MASK);
retry_cpuset:
cpuset_mems_cookie = get_mems_allowed();
zonelist = node_zonelist(slab_node(), flags);
retry:
/*
* Look through allowed nodes for objects available
* from existing per node queues.
*/
for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) {
nid = zone_to_nid(zone);
if (cpuset_zone_allowed_hardwall(zone, flags) &&
cache->nodelists[nid] &&
cache->nodelists[nid]->free_objects) {
obj = ____cache_alloc_node(cache,
flags | GFP_THISNODE, nid);
if (obj)
break;
}
}
if (!obj) {
/*
* This allocation will be performed within the constraints
* of the current cpuset / memory policy requirements.
* We may trigger various forms of reclaim on the allowed
* set and go into memory reserves if necessary.
*/
if (local_flags & __GFP_WAIT)
local_irq_enable();
kmem_flagcheck(cache, flags);
obj = kmem_getpages(cache, local_flags, numa_mem_id());
if (local_flags & __GFP_WAIT)
local_irq_disable();
if (obj) {
/*
* Insert into the appropriate per node queues
*/
nid = page_to_nid(virt_to_page(obj));
if (cache_grow(cache, flags, nid, obj)) {
obj = ____cache_alloc_node(cache,
flags | GFP_THISNODE, nid);
if (!obj)
/*
* Another processor may allocate the
* objects in the slab since we are
* not holding any locks.
*/
goto retry;
} else {
/* cache_grow already freed obj */
obj = NULL;
}
}
}
if (unlikely(!put_mems_allowed(cpuset_mems_cookie) && !obj))
goto retry_cpuset;
return obj;
}
/*
* A interface to enable slab creation on nodeid
*/
static void *____cache_alloc_node(struct kmem_cache *cachep, gfp_t flags,
int nodeid)
{
struct list_head *entry;
struct slab *slabp;
struct kmem_list3 *l3;
void *obj;
int x;
l3 = cachep->nodelists[nodeid];
BUG_ON(!l3);
retry:
check_irq_off();
spin_lock(&l3->list_lock);
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_spinlock_acquired_node(cachep, nodeid);
check_slabp(cachep, slabp);
STATS_INC_NODEALLOCS(cachep);
STATS_INC_ACTIVE(cachep);
STATS_SET_HIGH(cachep);
BUG_ON(slabp->inuse == cachep->num);
obj = slab_get_obj(cachep, slabp, nodeid);
check_slabp(cachep, slabp);
l3->free_objects--;
/* 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);
spin_unlock(&l3->list_lock);
goto done;
must_grow:
spin_unlock(&l3->list_lock);
x = cache_grow(cachep, flags | GFP_THISNODE, nodeid, NULL);
if (x)
goto retry;
return fallback_alloc(cachep, flags);
done:
return obj;
}
/**
* 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.
* @caller: return address of caller, used for debug information
*
* Identical to kmem_cache_alloc but it will allocate memory on the given
* node, which can improve the performance for cpu bound structures.
*
* Fallback to other node is possible if __GFP_THISNODE is not set.
*/
static __always_inline void *
__cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid,
void *caller)
{
unsigned long save_flags;
void *ptr;
int slab_node = numa_mem_id();
flags &= gfp_allowed_mask;
lockdep_trace_alloc(flags);
if (slab_should_failslab(cachep, flags))
return NULL;
cache_alloc_debugcheck_before(cachep, flags);
local_irq_save(save_flags);
if (nodeid == NUMA_NO_NODE)
nodeid = slab_node;
if (unlikely(!cachep->nodelists[nodeid])) {
/* Node not bootstrapped yet */
ptr = fallback_alloc(cachep, flags);
goto out;
}
if (nodeid == slab_node) {
/*
* Use the locally cached objects if possible.
* However ____cache_alloc does not allow fallback
* to other nodes. It may fail while we still have
* objects on other nodes available.
*/
ptr = ____cache_alloc(cachep, flags);
if (ptr)
goto out;
}
/* ___cache_alloc_node can fall back to other nodes */
ptr = ____cache_alloc_node(cachep, flags, nodeid);
out:
local_irq_restore(save_flags);
ptr = cache_alloc_debugcheck_after(cachep, flags, ptr, caller);
kmemleak_alloc_recursive(ptr, cachep->object_size, 1, cachep->flags,
flags);
if (likely(ptr))
kmemcheck_slab_alloc(cachep, flags, ptr, cachep->object_size);
if (unlikely((flags & __GFP_ZERO) && ptr))
memset(ptr, 0, cachep->object_size);
return ptr;
}
static __always_inline void *
__do_cache_alloc(struct kmem_cache *cache, gfp_t flags)
{
void *objp;
if (unlikely(current->flags & (PF_SPREAD_SLAB | PF_MEMPOLICY))) {
objp = alternate_node_alloc(cache, flags);
if (objp)
goto out;
}
objp = ____cache_alloc(cache, flags);
/*
* We may just have run out of memory on the local node.
* ____cache_alloc_node() knows how to locate memory on other nodes
*/
if (!objp)
objp = ____cache_alloc_node(cache, flags, numa_mem_id());
out:
return objp;
}
#else
static __always_inline void *
__do_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
{
return ____cache_alloc(cachep, flags);
}
#endif /* CONFIG_NUMA */
static __always_inline void *
__cache_alloc(struct kmem_cache *cachep, gfp_t flags, void *caller)
{
unsigned long save_flags;
void *objp;
flags &= gfp_allowed_mask;
lockdep_trace_alloc(flags);
if (slab_should_failslab(cachep, flags))
return NULL;
cache_alloc_debugcheck_before(cachep, flags);
local_irq_save(save_flags);
objp = __do_cache_alloc(cachep, flags);
local_irq_restore(save_flags);
objp = cache_alloc_debugcheck_after(cachep, flags, objp, caller);
kmemleak_alloc_recursive(objp, cachep->object_size, 1, cachep->flags,
flags);
prefetchw(objp);
if (likely(objp))
kmemcheck_slab_alloc(cachep, flags, objp, cachep->object_size);
if (unlikely((flags & __GFP_ZERO) && objp))
memset(objp, 0, cachep->object_size);
return objp;
}
/*
* Caller needs to acquire correct kmem_list's list_lock
*/
static void free_block(struct kmem_cache *cachep, void **objpp, int nr_objects,
int node)
{
int i;
struct kmem_list3 *l3;
for (i = 0; i < nr_objects; i++) {
void *objp;
struct slab *slabp;
clear_obj_pfmemalloc(&objpp[i]);
objp = objpp[i];
slabp = virt_to_slab(objp);
l3 = cachep->nodelists[node];
list_del(&slabp->list);
check_spinlock_acquired_node(cachep, node);
check_slabp(cachep, slabp);
slab_put_obj(cachep, slabp, objp, node);
STATS_DEC_ACTIVE(cachep);
l3->free_objects++;
check_slabp(cachep, slabp);
/* fixup slab chains */
if (slabp->inuse == 0) {
if (l3->free_objects > l3->free_limit) {
l3->free_objects -= cachep->num;
/* No need to drop any previously held
* lock here, even if we have a off-slab slab
* descriptor it is guaranteed to come from
* a different cache, refer to comments before
* alloc_slabmgmt.
*/
slab_destroy(cachep, slabp);
} else {
list_add(&slabp->list, &l3->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, &l3->slabs_partial);
}
}
}
static void cache_flusharray(struct kmem_cache *cachep, struct array_cache *ac)
{
int batchcount;
struct kmem_list3 *l3;
int node = numa_mem_id();
batchcount = ac->batchcount;
#if DEBUG
BUG_ON(!batchcount || batchcount > ac->avail);
#endif
check_irq_off();
l3 = cachep->nodelists[node];
spin_lock(&l3->list_lock);
if (l3->shared) {
struct array_cache *shared_array = l3->shared;
int max = shared_array->limit - shared_array->avail;
if (max) {
if (batchcount > max)
batchcount = max;
memcpy(&(shared_array->entry[shared_array->avail]),
ac->entry, sizeof(void *) * batchcount);
shared_array->avail += batchcount;
goto free_done;
}
}
free_block(cachep, ac->entry, batchcount, node);
free_done:
#if STATS
{
int i = 0;
struct list_head *p;
p = l3->slabs_free.next;
while (p != &(l3->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(&l3->list_lock);
ac->avail -= batchcount;
memmove(ac->entry, &(ac->entry[batchcount]), sizeof(void *)*ac->avail);
}
/*
* 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(struct kmem_cache *cachep, void *objp,
void *caller)
{
struct array_cache *ac = cpu_cache_get(cachep);
check_irq_off();
kmemleak_free_recursive(objp, cachep->flags);
objp = cache_free_debugcheck(cachep, objp, caller);
kmemcheck_slab_free(cachep, objp, cachep->object_size);
/*
* Skip calling cache_free_alien() when the platform is not numa.
* This will avoid cache misses that happen while accessing slabp (which
* is per page memory reference) to get nodeid. Instead use a global
* variable to skip the call, which is mostly likely to be present in
* the cache.
*/
if (nr_online_nodes > 1 && cache_free_alien(cachep, objp))
return;
if (likely(ac->avail < ac->limit)) {
STATS_INC_FREEHIT(cachep);
} else {
STATS_INC_FREEMISS(cachep);
cache_flusharray(cachep, ac);
}
ac_put_obj(cachep, ac, 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(struct kmem_cache *cachep, gfp_t flags)
{
void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
trace_kmem_cache_alloc(_RET_IP_, ret,
cachep->object_size, cachep->size, flags);
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc);
#ifdef CONFIG_TRACING
void *
kmem_cache_alloc_trace(size_t size, struct kmem_cache *cachep, gfp_t flags)
{
void *ret;
ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
trace_kmalloc(_RET_IP_, ret,
size, slab_buffer_size(cachep), flags);
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc_trace);
#endif
#ifdef CONFIG_NUMA
void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
{
void *ret = __cache_alloc_node(cachep, flags, nodeid,
__builtin_return_address(0));
trace_kmem_cache_alloc_node(_RET_IP_, ret,
cachep->object_size, cachep->size,
flags, nodeid);
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc_node);
#ifdef CONFIG_TRACING
void *kmem_cache_alloc_node_trace(size_t size,
struct kmem_cache *cachep,
gfp_t flags,
int nodeid)
{
void *ret;
ret = __cache_alloc_node(cachep, flags, nodeid,
__builtin_return_address(0));
trace_kmalloc_node(_RET_IP_, ret,
size, slab_buffer_size(cachep),
flags, nodeid);
return ret;
}
EXPORT_SYMBOL(kmem_cache_alloc_node_trace);
#endif
static __always_inline void *
__do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller)
{
struct kmem_cache *cachep;
cachep = kmem_find_general_cachep(size, flags);
if (unlikely(ZERO_OR_NULL_PTR(cachep)))
return cachep;
return kmem_cache_alloc_node_trace(size, cachep, flags, node);
}
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
return __do_kmalloc_node(size, flags, node,
__builtin_return_address(0));
}
EXPORT_SYMBOL(__kmalloc_node);
void *__kmalloc_node_track_caller(size_t size, gfp_t flags,
int node, unsigned long caller)
{
return __do_kmalloc_node(size, flags, node, (void *)caller);
}
EXPORT_SYMBOL(__kmalloc_node_track_caller);
#else
void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
return __do_kmalloc_node(size, flags, node, NULL);
}
EXPORT_SYMBOL(__kmalloc_node);
#endif /* CONFIG_DEBUG_SLAB || CONFIG_TRACING */
#endif /* CONFIG_NUMA */
/**
* __do_kmalloc - allocate memory
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate (see kmalloc).
* @caller: function caller for debug tracking of the caller
*/
static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
void *caller)
{
struct kmem_cache *cachep;
void *ret;
/* If you want to save a few bytes .text space: replace
* __ with kmem_.
* Then kmalloc uses the uninlined functions instead of the inline
* functions.
*/
cachep = __find_general_cachep(size, flags);
if (unlikely(ZERO_OR_NULL_PTR(cachep)))
return cachep;
ret = __cache_alloc(cachep, flags, caller);
trace_kmalloc((unsigned long) caller, ret,
size, cachep->size, flags);
return ret;
}
#if defined(CONFIG_DEBUG_SLAB) || defined(CONFIG_TRACING)
void *__kmalloc(size_t size, gfp_t flags)
{
return __do_kmalloc(size, flags, __builtin_return_address(0));
}
EXPORT_SYMBOL(__kmalloc);
void *__kmalloc_track_caller(size_t size, gfp_t flags, unsigned long caller)
{
return __do_kmalloc(size, flags, (void *)caller);
}
EXPORT_SYMBOL(__kmalloc_track_caller);
#else
void *__kmalloc(size_t size, gfp_t flags)
{
return __do_kmalloc(size, flags, NULL);
}
EXPORT_SYMBOL(__kmalloc);
#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(struct kmem_cache *cachep, void *objp)
{
unsigned long flags;
local_irq_save(flags);
debug_check_no_locks_freed(objp, cachep->object_size);
if (!(cachep->flags & SLAB_DEBUG_OBJECTS))
debug_check_no_obj_freed(objp, cachep->object_size);
__cache_free(cachep, objp, __builtin_return_address(0));
local_irq_restore(flags);
trace_kmem_cache_free(_RET_IP_, objp);
}
EXPORT_SYMBOL(kmem_cache_free);
/**
* kfree - free previously allocated memory
* @objp: pointer returned by kmalloc.
*
* If @objp is NULL, no operation is performed.
*
* Don't free memory not originally allocated by kmalloc()
* or you will run into trouble.
*/
void kfree(const void *objp)
{
struct kmem_cache *c;
unsigned long flags;
trace_kfree(_RET_IP_, objp);
if (unlikely(ZERO_OR_NULL_PTR(objp)))
return;
local_irq_save(flags);
kfree_debugcheck(objp);
c = virt_to_cache(objp);
debug_check_no_locks_freed(objp, c->object_size);
debug_check_no_obj_freed(objp, c->object_size);
__cache_free(c, (void *)objp, __builtin_return_address(0));
local_irq_restore(flags);
}
EXPORT_SYMBOL(kfree);
unsigned int kmem_cache_size(struct kmem_cache *cachep)
{
return cachep->object_size;
}
EXPORT_SYMBOL(kmem_cache_size);
/*
* This initializes kmem_list3 or resizes various caches for all nodes.
*/
static int alloc_kmemlist(struct kmem_cache *cachep, gfp_t gfp)
{
int node;
struct kmem_list3 *l3;
struct array_cache *new_shared;
struct array_cache **new_alien = NULL;
for_each_online_node(node) {
if (use_alien_caches) {
new_alien = alloc_alien_cache(node, cachep->limit, gfp);
if (!new_alien)
goto fail;
}
new_shared = NULL;
if (cachep->shared) {
new_shared = alloc_arraycache(node,
cachep->shared*cachep->batchcount,
0xbaadf00d, gfp);
if (!new_shared) {
free_alien_cache(new_alien);
goto fail;
}
}
l3 = cachep->nodelists[node];
if (l3) {
struct array_cache *shared = l3->shared;