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/*
* 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
*
* 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.
*
* 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.
*
* On SMP systems, 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.
* This reduces the number of spinlock operations.
*
* The c_cpuarray may not be read with enabled local interrupts.
*
* SMP synchronization:
* constructors and destructors are called without any locking.
* Several members in kmem_cache_t and slab_t never change, they
* are accessed without any locking.
* The per-cpu arrays are never accessed from the wrong cpu, no locking.
* The non-constant members are protected with a per-cache irq spinlock.
*
* Further notes from the original documentation:
*
* 11 April '97. Started multi-threading - markhe
* The global cache-chain is protected by the semaphore 'cache_chain_sem'.
* The sem is only needed when accessing/extending the cache-chain, which
* can never happen inside an interrupt (kmem_cache_create(),
* kmem_cache_shrink() and kmem_cache_reap()).
*
* To prevent kmem_cache_shrink() trying to shrink a 'growing' cache (which
* maybe be sleeping and therefore not holding the semaphore/lock), the
* growing field is used. This also prevents reaping from a cache.
*
* At present, each engine can be growing a cache. This should be blocked.
*
*/
#include <linux/config.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/compiler.h>
#include <linux/seq_file.h>
#include <asm/uaccess.h>
/*
* DEBUG - 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
* SLAB_RED_ZONE & SLAB_POISON.
* 0 for faster, smaller code (especially in the critical paths).
*
* STATS - 1 to collect stats for /proc/slabinfo.
* 0 for faster, smaller code (especially in the critical paths).
*
* FORCED_DEBUG - 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
*/
#ifdef CONFIG_DEBUG_SLAB
#define DEBUG 1
#define STATS 1
#define FORCED_DEBUG 1
#else
#define DEBUG 0
#define STATS 0
#define FORCED_DEBUG 0
#endif
/*
* Parameters for kmem_cache_reap
*/
#define REAP_SCANLEN 10
#define REAP_PERFECT 10
/* Shouldn't this be in a header file somewhere? */
#define BYTES_PER_WORD sizeof(void *)
/* Legal flag mask for kmem_cache_create(). */
#if DEBUG
# define CREATE_MASK (SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
SLAB_POISON | SLAB_HWCACHE_ALIGN | \
SLAB_NO_REAP | SLAB_CACHE_DMA | \
SLAB_MUST_HWCACHE_ALIGN)
#else
# define CREATE_MASK (SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \
SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN)
#endif
/*
* kmem_bufctl_t:
*
* Bufctl's are used for linking objs within a slab
* linked offsets.
*
* This implementation relies on "struct page" for locating the cache &
* slab an object belongs to.
* This allows the bufctl structure to be small (one int), but limits
* the number of objects a slab (not a cache) can contain when off-slab
* bufctls are used. The limit is the size of the largest general cache
* that does not use off-slab slabs.
* For 32bit archs with 4 kB pages, is this 56.
* This is not serious, as it is only for large objects, when it is unwise
* to have too many per slab.
* Note: This limit can be raised by introducing a general cache whose size
* is less than 512 (PAGE_SIZE<<3), but greater than 256.
*/
#define BUFCTL_END 0xffffFFFF
#define SLAB_LIMIT 0xffffFFFE
typedef unsigned int kmem_bufctl_t;
/* Max number of objs-per-slab for caches which use off-slab slabs.
* Needed to avoid a possible looping condition in kmem_cache_grow().
*/
static unsigned long offslab_limit;
/*
* slab_t
*
* 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.
*/
typedef struct slab_s {
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;
} slab_t;
#define slab_bufctl(slabp) \
((kmem_bufctl_t *)(((slab_t*)slabp)+1))
/*
* cpucache_t
*
* Per cpu structures
* The limit is stored in the per-cpu structure to reduce the data cache
* footprint.
*/
typedef struct cpucache_s {
unsigned int avail;
unsigned int limit;
} cpucache_t;
#define cc_entry(cpucache) \
((void **)(((cpucache_t*)(cpucache))+1))
#define cc_data(cachep) \
((cachep)->cpudata[smp_processor_id()])
/*
* kmem_cache_t
*
* manages a cache.
*/
#define CACHE_NAMELEN 20 /* max name length for a slab cache */
struct kmem_cache_s {
/* 1) each alloc & free */
/* full, partial first, then free */
struct list_head slabs_full;
struct list_head slabs_partial;
struct list_head slabs_free;
unsigned int objsize;
unsigned int flags; /* constant flags */
unsigned int num; /* # of objs per slab */
spinlock_t spinlock;
#ifdef CONFIG_SMP
unsigned int batchcount;
#endif
/* 2) slab additions /removals */
/* order of pgs per slab (2^n) */
unsigned int gfporder;
/* force GFP flags, e.g. GFP_DMA */
unsigned int gfpflags;
size_t colour; /* cache colouring range */
unsigned int colour_off; /* colour offset */
unsigned int colour_next; /* cache colouring */
kmem_cache_t *slabp_cache;
unsigned int growing;
unsigned int dflags; /* dynamic flags */
/* constructor func */
void (*ctor)(void *, kmem_cache_t *, unsigned long);
/* de-constructor func */
void (*dtor)(void *, kmem_cache_t *, unsigned long);
unsigned long failures;
/* 3) cache creation/removal */
char name[CACHE_NAMELEN];
struct list_head next;
#ifdef CONFIG_SMP
/* 4) per-cpu data */
cpucache_t *cpudata[NR_CPUS];
#endif
#if STATS
unsigned long num_active;
unsigned long num_allocations;
unsigned long high_mark;
unsigned long grown;
unsigned long reaped;
unsigned long errors;
#ifdef CONFIG_SMP
atomic_t allochit;
atomic_t allocmiss;
atomic_t freehit;
atomic_t freemiss;
#endif
#endif
};
/* internal c_flags */
#define CFLGS_OFF_SLAB 0x010000UL /* slab management in own cache */
#define CFLGS_OPTIMIZE 0x020000UL /* optimized slab lookup */
/* c_dflags (dynamic flags). Need to hold the spinlock to access this member */
#define DFLGS_GROWN 0x000001UL /* don't reap a recently grown */
#define OFF_SLAB(x) ((x)->flags & CFLGS_OFF_SLAB)
#define OPTIMIZE(x) ((x)->flags & CFLGS_OPTIMIZE)
#define GROWN(x) ((x)->dlags & DFLGS_GROWN)
#if STATS
#define STATS_INC_ACTIVE(x) ((x)->num_active++)
#define STATS_DEC_ACTIVE(x) ((x)->num_active--)
#define STATS_INC_ALLOCED(x) ((x)->num_allocations++)
#define STATS_INC_GROWN(x) ((x)->grown++)
#define STATS_INC_REAPED(x) ((x)->reaped++)
#define STATS_SET_HIGH(x) do { if ((x)->num_active > (x)->high_mark) \
(x)->high_mark = (x)->num_active; \
} while (0)
#define STATS_INC_ERR(x) ((x)->errors++)
#else
#define STATS_INC_ACTIVE(x) do { } while (0)
#define STATS_DEC_ACTIVE(x) do { } while (0)
#define STATS_INC_ALLOCED(x) do { } while (0)
#define STATS_INC_GROWN(x) do { } while (0)
#define STATS_INC_REAPED(x) do { } while (0)
#define STATS_SET_HIGH(x) do { } while (0)
#define STATS_INC_ERR(x) do { } while (0)
#endif
#if STATS && defined(CONFIG_SMP)
#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_ALLOCHIT(x) do { } while (0)
#define STATS_INC_ALLOCMISS(x) do { } while (0)
#define STATS_INC_FREEHIT(x) do { } while (0)
#define STATS_INC_FREEMISS(x) do { } while (0)
#endif
#if DEBUG
/* Magic nums for obj red zoning.
* Placed in the first word before and the first word after an obj.
*/
#define RED_MAGIC1 0x5A2CF071UL /* when obj is active */
#define RED_MAGIC2 0x170FC2A5UL /* when obj is inactive */
/* ...and for poisoning */
#define POISON_BYTE 0x5a /* byte value for poisoning */
#define POISON_END 0xa5 /* end-byte of poisoning */
#endif
/* maximum size of an obj (in 2^order pages) */
#define MAX_OBJ_ORDER 5 /* 32 pages */
/*
* Do not go above this order unless 0 objects fit into the slab.
*/
#define BREAK_GFP_ORDER_HI 2
#define BREAK_GFP_ORDER_LO 1
static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
/*
* Absolute limit for the gfp order
*/
#define MAX_GFP_ORDER 5 /* 32 pages */
/* Macros for storing/retrieving the cachep and or slab from the
* global 'mem_map'. These are used to find the slab an obj belongs to.
* With kfree(), these are used to find the cache which an obj belongs to.
*/
#define SET_PAGE_CACHE(pg,x) ((pg)->list.next = (struct list_head *)(x))
#define GET_PAGE_CACHE(pg) ((kmem_cache_t *)(pg)->list.next)
#define SET_PAGE_SLAB(pg,x) ((pg)->list.prev = (struct list_head *)(x))
#define GET_PAGE_SLAB(pg) ((slab_t *)(pg)->list.prev)
/* Size description struct for general caches. */
typedef struct cache_sizes {
size_t cs_size;
kmem_cache_t *cs_cachep;
kmem_cache_t *cs_dmacachep;
} cache_sizes_t;
static cache_sizes_t cache_sizes[] = {
#if PAGE_SIZE == 4096
{ 32, NULL, NULL},
#endif
{ 64, NULL, NULL},
{ 128, NULL, NULL},
{ 256, NULL, NULL},
{ 512, NULL, NULL},
{ 1024, NULL, NULL},
{ 2048, NULL, NULL},
{ 4096, NULL, NULL},
{ 8192, NULL, NULL},
{ 16384, NULL, NULL},
{ 32768, NULL, NULL},
{ 65536, NULL, NULL},
{131072, NULL, NULL},
{ 0, NULL, NULL}
};
/* internal cache of cache description objs */
static kmem_cache_t cache_cache = {
slabs_full: LIST_HEAD_INIT(cache_cache.slabs_full),
slabs_partial: LIST_HEAD_INIT(cache_cache.slabs_partial),
slabs_free: LIST_HEAD_INIT(cache_cache.slabs_free),
objsize: sizeof(kmem_cache_t),
flags: SLAB_NO_REAP,
spinlock: SPIN_LOCK_UNLOCKED,
colour_off: L1_CACHE_BYTES,
name: "kmem_cache",
};
/* Guard access to the cache-chain. */
static struct semaphore cache_chain_sem;
/* Place maintainer for reaping. */
static kmem_cache_t *clock_searchp = &cache_cache;
#define cache_chain (cache_cache.next)
#ifdef CONFIG_SMP
/*
* chicken and egg problem: delay the per-cpu array allocation
* until the general caches are up.
*/
static int g_cpucache_up;
static void enable_cpucache (kmem_cache_t *cachep);
static void enable_all_cpucaches (void);
#endif
/* Cal the num objs, wastage, and bytes left over for a given slab size. */
static void kmem_cache_estimate (unsigned long gfporder, size_t size,
int flags, size_t *left_over, unsigned int *num)
{
int i;
size_t wastage = PAGE_SIZE<<gfporder;
size_t extra = 0;
size_t base = 0;
if (!(flags & CFLGS_OFF_SLAB)) {
base = sizeof(slab_t);
extra = sizeof(kmem_bufctl_t);
}
i = 0;
while (i*size + L1_CACHE_ALIGN(base+i*extra) <= wastage)
i++;
if (i > 0)
i--;
if (i > SLAB_LIMIT)
i = SLAB_LIMIT;
*num = i;
wastage -= i*size;
wastage -= L1_CACHE_ALIGN(base+i*extra);
*left_over = wastage;
}
/* Initialisation - setup the `cache' cache. */
void __init kmem_cache_init(void)
{
size_t left_over;
init_MUTEX(&cache_chain_sem);
INIT_LIST_HEAD(&cache_chain);
kmem_cache_estimate(0, cache_cache.objsize, 0,
&left_over, &cache_cache.num);
if (!cache_cache.num)
BUG();
cache_cache.colour = left_over/cache_cache.colour_off;
cache_cache.colour_next = 0;
}
/* Initialisation - setup remaining internal and general caches.
* Called after the gfp() functions have been enabled, and before smp_init().
*/
void __init kmem_cache_sizes_init(void)
{
cache_sizes_t *sizes = cache_sizes;
char name[20];
/*
* Fragmentation resistance on low memory - only use bigger
* page orders on machines with more than 32MB of memory.
*/
if (num_physpages > (32 << 20) >> PAGE_SHIFT)
slab_break_gfp_order = BREAK_GFP_ORDER_HI;
do {
/* 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. */
snprintf(name, sizeof(name), "size-%Zd",sizes->cs_size);
if (!(sizes->cs_cachep =
kmem_cache_create(name, sizes->cs_size,
0, SLAB_HWCACHE_ALIGN, NULL, NULL))) {
BUG();
}
/* Inc off-slab bufctl limit until the ceiling is hit. */
if (!(OFF_SLAB(sizes->cs_cachep))) {
offslab_limit = sizes->cs_size-sizeof(slab_t);
offslab_limit /= 2;
}
snprintf(name, sizeof(name), "size-%Zd(DMA)",sizes->cs_size);
sizes->cs_dmacachep = kmem_cache_create(name, sizes->cs_size, 0,
SLAB_CACHE_DMA|SLAB_HWCACHE_ALIGN, NULL, NULL);
if (!sizes->cs_dmacachep)
BUG();
sizes++;
} while (sizes->cs_size);
}
int __init kmem_cpucache_init(void)
{
#ifdef CONFIG_SMP
g_cpucache_up = 1;
enable_all_cpucaches();
#endif
return 0;
}
__initcall(kmem_cpucache_init);
/* Interface to system's page allocator. No need to hold the cache-lock.
*/
static inline void * kmem_getpages (kmem_cache_t *cachep, unsigned long flags)
{
void *addr;
/*
* 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.
*/
flags |= cachep->gfpflags;
addr = (void*) __get_free_pages(flags, cachep->gfporder);
/* Assume that now we have the pages no one else can legally
* messes with the 'struct page's.
* However vm_scan() might try to test the structure to see if
* it is a named-page or buffer-page. The members it tests are
* of no interest here.....
*/
return addr;
}
/* Interface to system's page release. */
static inline void kmem_freepages (kmem_cache_t *cachep, void *addr)
{
unsigned long i = (1<<cachep->gfporder);
struct page *page = virt_to_page(addr);
/* free_pages() does not clear the type bit - we do that.
* The pages have been unlinked from their cache-slab,
* but their 'struct page's might be accessed in
* vm_scan(). Shouldn't be a worry.
*/
while (i--) {
PageClearSlab(page);
page++;
}
free_pages((unsigned long)addr, cachep->gfporder);
}
#if DEBUG
static inline void kmem_poison_obj (kmem_cache_t *cachep, void *addr)
{
int size = cachep->objsize;
if (cachep->flags & SLAB_RED_ZONE) {
addr += BYTES_PER_WORD;
size -= 2*BYTES_PER_WORD;
}
memset(addr, POISON_BYTE, size);
*(unsigned char *)(addr+size-1) = POISON_END;
}
static inline int kmem_check_poison_obj (kmem_cache_t *cachep, void *addr)
{
int size = cachep->objsize;
void *end;
if (cachep->flags & SLAB_RED_ZONE) {
addr += BYTES_PER_WORD;
size -= 2*BYTES_PER_WORD;
}
end = memchr(addr, POISON_END, size);
if (end != (addr+size-1))
return 1;
return 0;
}
#endif
/* Destroy all the objs in a slab, and release the mem back to the system.
* Before calling the slab must have been unlinked from the cache.
* The cache-lock is not held/needed.
*/
static void kmem_slab_destroy (kmem_cache_t *cachep, slab_t *slabp)
{
if (cachep->dtor
#if DEBUG
|| cachep->flags & (SLAB_POISON | SLAB_RED_ZONE)
#endif
) {
int i;
for (i = 0; i < cachep->num; i++) {
void* objp = slabp->s_mem+cachep->objsize*i;
#if DEBUG
if (cachep->flags & SLAB_RED_ZONE) {
if (*((unsigned long*)(objp)) != RED_MAGIC1)
BUG();
if (*((unsigned long*)(objp + cachep->objsize
-BYTES_PER_WORD)) != RED_MAGIC1)
BUG();
objp += BYTES_PER_WORD;
}
#endif
if (cachep->dtor)
(cachep->dtor)(objp, cachep, 0);
#if DEBUG
if (cachep->flags & SLAB_RED_ZONE) {
objp -= BYTES_PER_WORD;
}
if ((cachep->flags & SLAB_POISON) &&
kmem_check_poison_obj(cachep, objp))
BUG();
#endif
}
}
kmem_freepages(cachep, slabp->s_mem-slabp->colouroff);
if (OFF_SLAB(cachep))
kmem_cache_free(cachep->slabp_cache, slabp);
}
/**
* kmem_cache_create - Create a cache.
* @name: A string which is used in /proc/slabinfo to identify this cache.
* @size: The size of objects to be created in this cache.
* @offset: The offset to use within the page.
* @flags: SLAB flags
* @ctor: A constructor for the objects.
* @dtor: A destructor for the objects.
*
* Returns a ptr to the cache on success, NULL on failure.
* Cannot be called within a int, but can be interrupted.
* The @ctor is run when new pages are allocated by the cache
* and the @dtor is run before the pages are handed back.
* The flags are
*
* %SLAB_POISON - Poison the slab with a known test pattern (a5a5a5a5)
* to catch references to uninitialised memory.
*
* %SLAB_RED_ZONE - Insert `Red' zones around the allocated memory to check
* for buffer overruns.
*
* %SLAB_NO_REAP - Don't automatically reap this cache when we're under
* memory pressure.
*
* %SLAB_HWCACHE_ALIGN - Align the objects in this cache to a hardware
* cacheline. This can be beneficial if you're counting cycles as closely
* as davem.
*/
kmem_cache_t *
kmem_cache_create (const char *name, size_t size, size_t offset,
unsigned long flags, void (*ctor)(void*, kmem_cache_t *, unsigned long),
void (*dtor)(void*, kmem_cache_t *, unsigned long))
{
const char *func_nm = KERN_ERR "kmem_create: ";
size_t left_over, align, slab_size;
kmem_cache_t *cachep = NULL;
/*
* Sanity checks... these are all serious usage bugs.
*/
if ((!name) ||
((strlen(name) >= CACHE_NAMELEN - 1)) ||
in_interrupt() ||
(size < BYTES_PER_WORD) ||
(size > (1<<MAX_OBJ_ORDER)*PAGE_SIZE) ||
(dtor && !ctor) ||
(offset < 0 || offset > size))
BUG();
#if DEBUG
if ((flags & SLAB_DEBUG_INITIAL) && !ctor) {
/* No constructor, but inital state check requested */
printk("%sNo con, but init state check requested - %s\n", func_nm, name);
flags &= ~SLAB_DEBUG_INITIAL;
}
if ((flags & SLAB_POISON) && ctor) {
/* request for poisoning, but we can't do that with a constructor */
printk("%sPoisoning requested, but con given - %s\n", func_nm, name);
flags &= ~SLAB_POISON;
}
#if FORCED_DEBUG
if ((size < (PAGE_SIZE>>3)) && !(flags & SLAB_MUST_HWCACHE_ALIGN))
/*
* do not red zone large object, causes severe
* fragmentation.
*/
flags |= SLAB_RED_ZONE;
if (!ctor)
flags |= SLAB_POISON;
#endif
#endif
/*
* Always checks flags, a caller might be expecting debug
* support which isn't available.
*/
BUG_ON(flags & ~CREATE_MASK);
/* Get cache's description obj. */
cachep = (kmem_cache_t *) kmem_cache_alloc(&cache_cache, SLAB_KERNEL);
if (!cachep)
goto opps;
memset(cachep, 0, sizeof(kmem_cache_t));
/* 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);
printk("%sForcing size word alignment - %s\n", func_nm, name);
}
#if DEBUG
if (flags & SLAB_RED_ZONE) {
/*
* There is no point trying to honour cache alignment
* when redzoning.
*/
flags &= ~SLAB_HWCACHE_ALIGN;
size += 2*BYTES_PER_WORD; /* words for redzone */
}
#endif
align = BYTES_PER_WORD;
if (flags & SLAB_HWCACHE_ALIGN)
align = L1_CACHE_BYTES;
/* Determine if the slab management is 'on' or 'off' slab. */
if (size >= (PAGE_SIZE>>3))
/*
* Size is large, assume best to place the slab management obj
* off-slab (should allow better packing of objs).
*/
flags |= CFLGS_OFF_SLAB;
if (flags & SLAB_HWCACHE_ALIGN) {
/* Need to adjust size so that objs are cache aligned. */
/* Small obj size, can get at least two per cache line. */
/* FIXME: only power of 2 supported, was better */
while (size < align/2)
align /= 2;
size = (size+align-1)&(~(align-1));
}
/* Cal size (in pages) of slabs, and the num of objs per slab.
* This could be made much more intelligent. For now, try to avoid
* using high page-orders for slabs. When the gfp() funcs are more
* friendly towards high-order requests, this should be changed.
*/
do {
unsigned int break_flag = 0;
cal_wastage:
kmem_cache_estimate(cachep->gfporder, size, flags,
&left_over, &cachep->num);
if (break_flag)
break;
if (cachep->gfporder >= MAX_GFP_ORDER)
break;
if (!cachep->num)
goto next;
if (flags & CFLGS_OFF_SLAB && cachep->num > offslab_limit) {
/* Oops, this num of objs will cause problems. */
cachep->gfporder--;
break_flag++;
goto cal_wastage;
}
/*
* Large num of objs is good, but v. large slabs are currently
* bad for the gfp()s.
*/
if (cachep->gfporder >= slab_break_gfp_order)
break;
if ((left_over*8) <= (PAGE_SIZE<<cachep->gfporder))
break; /* Acceptable internal fragmentation. */
next:
cachep->gfporder++;
} while (1);
if (!cachep->num) {
printk("kmem_cache_create: couldn't create cache %s.\n", name);
kmem_cache_free(&cache_cache, cachep);
cachep = NULL;
goto opps;
}
slab_size = L1_CACHE_ALIGN(cachep->num*sizeof(kmem_bufctl_t)+sizeof(slab_t));
/*
* 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;
}
/* Offset must be a multiple of the alignment. */
offset += (align-1);
offset &= ~(align-1);
if (!offset)
offset = L1_CACHE_BYTES;
cachep->colour_off = offset;
cachep->colour = left_over/offset;
/* init remaining fields */
if (!cachep->gfporder && !(flags & CFLGS_OFF_SLAB))
flags |= CFLGS_OPTIMIZE;
cachep->flags = flags;
cachep->gfpflags = 0;
if (flags & SLAB_CACHE_DMA)
cachep->gfpflags |= GFP_DMA;
spin_lock_init(&cachep->spinlock);
cachep->objsize = size;
INIT_LIST_HEAD(&cachep->slabs_full);
INIT_LIST_HEAD(&cachep->slabs_partial);
INIT_LIST_HEAD(&cachep->slabs_free);
if (flags & CFLGS_OFF_SLAB)
cachep->slabp_cache = kmem_find_general_cachep(slab_size,0);
cachep->ctor = ctor;
cachep->dtor = dtor;
/* Copy name over so we don't have problems with unloaded modules */
strcpy(cachep->name, name);
#ifdef CONFIG_SMP
if (g_cpucache_up)
enable_cpucache(cachep);
#endif
/* Need the semaphore to access the chain. */
down(&cache_chain_sem);
{
struct list_head *p;
list_for_each(p, &cache_chain) {
kmem_cache_t *pc = list_entry(p, kmem_cache_t, next);
/* The name field is constant - no lock needed. */
if (!strcmp(pc->name, name))
BUG();
}
}
/* There is no reason to lock our new cache before we
* link it in - no one knows about it yet...
*/
list_add(&cachep->next, &cache_chain);
up(&cache_chain_sem);
opps:
return cachep;
}
#if DEBUG
/*
* This check if the kmem_cache_t pointer is chained in the cache_cache
* list. -arca
*/
static int is_chained_kmem_cache(kmem_cache_t * cachep)
{
struct list_head *p;
int ret = 0;
/* Find the cache in the chain of caches. */
down(&cache_chain_sem);
list_for_each(p, &cache_chain) {
if (p == &cachep->next) {
ret = 1;
break;
}
}
up(&cache_chain_sem);
return ret;
}
#else
#define is_chained_kmem_cache(x) 1
#endif
#ifdef CONFIG_SMP
/*
* Waits for all CPUs to execute func().
*/
static void smp_call_function_all_cpus(void (*func) (void *arg), void *arg)
{
local_irq_disable();
func(arg);
local_irq_enable();
if (smp_call_function(func, arg, 1, 1))
BUG();
}
typedef struct ccupdate_struct_s
{
kmem_cache_t *cachep;
cpucache_t *new[NR_CPUS];
} ccupdate_struct_t;
static void do_ccupdate_local(void *info)
{
ccupdate_struct_t *new = (ccupdate_struct_t *)info;
cpucache_t *old = cc_data(new->cachep);
cc_data(new->cachep) = new->new[smp_processor_id()];
new->new[smp_processor_id()] = old;
}
static void free_block (kmem_cache_t* cachep, void** objpp, int len);
static void drain_cpu_caches(kmem_cache_t *cachep)
{
ccupdate_struct_t new;
int i;
memset(&new.new,0,sizeof(new.new));
new.cachep = cachep;
down(&cache_chain_sem);
smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
for (i = 0; i < smp_num_cpus; i++) {
cpucache_t* ccold = new.new[cpu_logical_map(i)];
if (!ccold || (ccold->avail == 0))
continue;
local_irq_disable();
free_block(cachep, cc_entry(ccold), ccold->avail);
local_irq_enable();
ccold->avail = 0;
}
smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
up(&cache_chain_sem);
}
#else
#define drain_cpu_caches(cachep) do { } while (0)
#endif
/*
* Called with the &cachep->spinlock held, returns number of slabs released
*/
static int __kmem_cache_shrink_locked(kmem_cache_t *cachep)
{
slab_t *slabp;
int ret = 0;
/* If the cache is growing, stop shrinking. */
while (!cachep->growing) {
struct list_head *p;
p = cachep->slabs_free.prev;
if (p == &cachep->slabs_free)
break;
slabp = list_entry(cachep->slabs_free.prev, slab_t, list);
#if DEBUG
if (slabp->inuse)
BUG();
#endif
list_del(&slabp->list);
spin_unlock_irq(&cachep->spinlock);
kmem_slab_destroy(cachep, slabp);
ret++;
spin_lock_irq(&cachep->spinlock);
}
return ret;
}
static int __kmem_cache_shrink(kmem_cache_t *cachep)
{
int ret;
drain_cpu_caches(cachep);
spin_lock_irq(&cachep->spinlock);
__kmem_cache_shrink_locked(cachep);
ret = !list_empty(&cachep->slabs_full) ||
!list_empty(&cachep->slabs_partial);
spin_unlock_irq(&cachep->spinlock);
return ret;
}
/**
* kmem_cache_shrink - Shrink a cache.
* @cachep: The cache to shrink.
*
* Releases as many slabs as possible for a cache.
* Returns number of pages released.
*/
int kmem_cache_shrink(kmem_cache_t *cachep)
{
int ret;
if (!cachep || in_interrupt() || !is_chained_kmem_cache(cachep))
BUG();
spin_lock_irq(&cachep->spinlock);
ret = __kmem_cache_shrink_locked(cachep);
spin_unlock_irq(&cachep->spinlock);
return ret << cachep->gfporder;
}
/**
* kmem_cache_destroy - delete a cache
* @cachep: the cache to destroy
*
* Remove a kmem_cache_t object from the slab cache.
* Returns 0 on success.
*
* It is expected this function will be called by a module when it is
* unloaded. This will remove the cache completely, and avoid a duplicate
* cache being allocated each time a module is loaded and unloaded, if the
* module doesn't have persistent in-kernel storage across loads and unloads.
*
* The cache must be empty before calling this function.
*
* The caller must guarantee that noone will allocate memory from the cache
* during the kmem_cache_destroy().
*/
int kmem_cache_destroy (kmem_cache_t * cachep)
{
if (!cachep || in_interrupt() || cachep->growing)
BUG();
/* Find the cache in the chain of caches. */
down(&cache_chain_sem);
/* the chain is never empty, cache_cache is never destroyed */
if (clock_searchp == cachep)
clock_searchp = list_entry(cachep->next.next,
kmem_cache_t, next);
list_del(&cachep->next);
up(&cache_chain_sem);
if (__kmem_cache_shrink(cachep)) {
printk(KERN_ERR "kmem_cache_destroy: Can't free all objects %p\n",
cachep);
down(&cache_chain_sem);
list_add(&cachep->next,&cache_chain);
up(&cache_chain_sem);
return 1;
}
#ifdef CONFIG_SMP
{
int i;
for (i = 0; i < NR_CPUS; i++)
kfree(cachep->cpudata[i]);
}
#endif
kmem_cache_free(&cache_cache, cachep);
return 0;
}
/* Get the memory for a slab management obj. */
static inline slab_t * kmem_cache_slabmgmt (kmem_cache_t *cachep,
void *objp, int colour_off, int local_flags)
{
slab_t *slabp;
if (OFF_SLAB(cachep)) {
/* Slab management obj is off-slab. */
slabp = kmem_cache_alloc(cachep->slabp_cache, local_flags);
if (!slabp)
return NULL;
} else {
/* FIXME: change to
slabp = objp
* if you enable OPTIMIZE
*/
slabp = objp+colour_off;
colour_off += L1_CACHE_ALIGN(cachep->num *
sizeof(kmem_bufctl_t) + sizeof(slab_t));
}
slabp->inuse = 0;
slabp->colouroff = colour_off;
slabp->s_mem = objp+colour_off;
return slabp;
}
static inline void kmem_cache_init_objs (kmem_cache_t * cachep,
slab_t * slabp, unsigned long ctor_flags)
{
int i;
for (i = 0; i < cachep->num; i++) {
void* objp = slabp->s_mem+cachep->objsize*i;
#if DEBUG
if (cachep->flags & SLAB_RED_ZONE) {
*((unsigned long*)(objp)) = RED_MAGIC1;
*((unsigned long*)(objp + cachep->objsize -
BYTES_PER_WORD)) = RED_MAGIC1;
objp += BYTES_PER_WORD;
}
#endif
/*
* 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->ctor(objp, cachep, ctor_flags);
#if DEBUG
if (cachep->flags & SLAB_RED_ZONE)
objp -= BYTES_PER_WORD;
if (cachep->flags & SLAB_POISON)
/* need to poison the objs */
kmem_poison_obj(cachep, objp);
if (cachep->flags & SLAB_RED_ZONE) {
if (*((unsigned long*)(objp)) != RED_MAGIC1)
BUG();
if (*((unsigned long*)(objp + cachep->objsize -
BYTES_PER_WORD)) != RED_MAGIC1)
BUG();
}
#endif
slab_bufctl(slabp)[i] = i+1;
}
slab_bufctl(slabp)[i-1] = BUFCTL_END;
slabp->free = 0;
}
/*
* 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 kmem_cache_grow (kmem_cache_t * cachep, int flags)
{
slab_t *slabp;
struct page *page;
void *objp;
size_t offset;
unsigned int i, local_flags;
unsigned long ctor_flags;
unsigned long save_flags;
/* Be lazy and only check for valid flags here,
* keeping it out of the critical path in kmem_cache_alloc().
*/
if (flags & ~(SLAB_DMA|SLAB_LEVEL_MASK|SLAB_NO_GROW))
BUG();
if (flags & SLAB_NO_GROW)
return 0;
/*
* 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).
*/
if (in_interrupt() && (flags & SLAB_LEVEL_MASK) != SLAB_ATOMIC)
BUG();
ctor_flags = SLAB_CTOR_CONSTRUCTOR;
local_flags = (flags & SLAB_LEVEL_MASK);
if (local_flags == SLAB_ATOMIC)
/*
* Not allowed to sleep. Need to tell a constructor about
* this - it might need to know...
*/
ctor_flags |= SLAB_CTOR_ATOMIC;
/* About to mess with non-constant members - lock. */
spin_lock_irqsave(&cachep->spinlock, save_flags);
/* Get colour for the slab, and cal the next value. */
offset = cachep->colour_next;
cachep->colour_next++;
if (cachep->colour_next >= cachep->colour)
cachep->colour_next = 0;
offset *= cachep->colour_off;
cachep->dflags |= DFLGS_GROWN;
cachep->growing++;
spin_unlock_irqrestore(&cachep->spinlock, save_flags);
/* A series of memory allocations for a new slab.
* Neither the cache-chain semaphore, or cache-lock, are
* held, but the incrementing c_growing prevents this
* cache from being reaped or shrunk.
* Note: The cache could be selected in for reaping in
* kmem_cache_reap(), but when the final test is made the
* growing value will be seen.
*/
/* Get mem for the objs. */
if (!(objp = kmem_getpages(cachep, flags)))
goto failed;
/* Get slab management. */
if (!(slabp = kmem_cache_slabmgmt(cachep, objp, offset, local_flags)))
goto opps1;
/* Nasty!!!!!! I hope this is OK. */
i = 1 << cachep->gfporder;
page = virt_to_page(objp);
do {
SET_PAGE_CACHE(page, cachep);
SET_PAGE_SLAB(page, slabp);
PageSetSlab(page);
page++;
} while (--i);
kmem_cache_init_objs(cachep, slabp, ctor_flags);
spin_lock_irqsave(&cachep->spinlock, save_flags);
cachep->growing--;
/* Make slab active. */
list_add_tail(&slabp->list, &cachep->slabs_free);
STATS_INC_GROWN(cachep);
cachep->failures = 0;
spin_unlock_irqrestore(&cachep->spinlock, save_flags);
return 1;
opps1:
kmem_freepages(cachep, objp);
failed:
spin_lock_irqsave(&cachep->spinlock, save_flags);
cachep->growing--;
spin_unlock_irqrestore(&cachep->spinlock, save_flags);
return 0;
}
/*
* Perform extra freeing checks:
* - detect double free
* - detect bad pointers.
* Called with the cache-lock held.
*/
#if DEBUG
static int kmem_extra_free_checks (kmem_cache_t * cachep,
slab_t *slabp, void * objp)
{
int i;
unsigned int objnr = (objp-slabp->s_mem)/cachep->objsize;
if (objnr >= cachep->num)
BUG();
if (objp != slabp->s_mem + objnr*cachep->objsize)
BUG();
/* Check slab's freelist to see if this obj is there. */
for (i = slabp->free; i != BUFCTL_END; i = slab_bufctl(slabp)[i]) {
if (i == objnr)
BUG();
}
return 0;
}
#endif
static inline void kmem_cache_alloc_head(kmem_cache_t *cachep, int flags)
{
if (flags & SLAB_DMA) {
if (!(cachep->gfpflags & GFP_DMA))
BUG();
} else {
if (cachep->gfpflags & GFP_DMA)
BUG();
}
}
static inline void * kmem_cache_alloc_one_tail (kmem_cache_t *cachep,
slab_t *slabp)
{
void *objp;
STATS_INC_ALLOCED(cachep);
STATS_INC_ACTIVE(cachep);
STATS_SET_HIGH(cachep);
/* get obj pointer */
slabp->inuse++;
objp = slabp->s_mem + slabp->free*cachep->objsize;
slabp->free=slab_bufctl(slabp)[slabp->free];
if (unlikely(slabp->free == BUFCTL_END)) {
list_del(&slabp->list);
list_add(&slabp->list, &cachep->slabs_full);
}
#if DEBUG
if (cachep->flags & SLAB_POISON)
if (kmem_check_poison_obj(cachep, objp))
BUG();
if (cachep->flags & SLAB_RED_ZONE) {
/* Set alloc red-zone, and check old one. */
if (xchg((unsigned long *)objp, RED_MAGIC2) !=
RED_MAGIC1)
BUG();
if (xchg((unsigned long *)(objp+cachep->objsize -
BYTES_PER_WORD), RED_MAGIC2) != RED_MAGIC1)
BUG();
objp += BYTES_PER_WORD;
}
#endif
return objp;
}
/*
* Returns a ptr to an obj in the given cache.
* caller must guarantee synchronization
* #define for the goto optimization 8-)
*/
#define kmem_cache_alloc_one(cachep) \
({ \
struct list_head * slabs_partial, * entry; \
slab_t *slabp; \
\
slabs_partial = &(cachep)->slabs_partial; \
entry = slabs_partial->next; \
if (unlikely(entry == slabs_partial)) { \
struct list_head * slabs_free; \
slabs_free = &(cachep)->slabs_free; \
entry = slabs_free->next; \
if (unlikely(entry == slabs_free)) \
goto alloc_new_slab; \
list_del(entry); \
list_add(entry, slabs_partial); \
} \
\
slabp = list_entry(entry, slab_t, list); \
kmem_cache_alloc_one_tail(cachep, slabp); \
})
#ifdef CONFIG_SMP
void* kmem_cache_alloc_batch(kmem_cache_t* cachep, cpucache_t* cc, int flags)
{
int batchcount = cachep->batchcount;
spin_lock(&cachep->spinlock);
while (batchcount--) {
struct list_head * slabs_partial, * entry;
slab_t *slabp;
/* Get slab alloc is to come from. */
slabs_partial = &(cachep)->slabs_partial;
entry = slabs_partial->next;
if (unlikely(entry == slabs_partial)) {
struct list_head * slabs_free;
slabs_free = &(cachep)->slabs_free;
entry = slabs_free->next;
if (unlikely(entry == slabs_free))
break;
list_del(entry);
list_add(entry, slabs_partial);
}
slabp = list_entry(entry, slab_t, list);
cc_entry(cc)[cc->avail++] =
kmem_cache_alloc_one_tail(cachep, slabp);
}
spin_unlock(&cachep->spinlock);
if (cc->avail)
return cc_entry(cc)[--cc->avail];
return NULL;
}
#endif
static inline void * __kmem_cache_alloc (kmem_cache_t *cachep, int flags)
{
unsigned long save_flags;
void* objp;
kmem_cache_alloc_head(cachep, flags);
try_again:
local_irq_save(save_flags);
#ifdef CONFIG_SMP
{
cpucache_t *cc = cc_data(cachep);
if (cc) {
if (cc->avail) {
STATS_INC_ALLOCHIT(cachep);
objp = cc_entry(cc)[--cc->avail];
} else {
STATS_INC_ALLOCMISS(cachep);
objp = kmem_cache_alloc_batch(cachep,cc,flags);
if (!objp)
goto alloc_new_slab_nolock;
}
} else {
spin_lock(&cachep->spinlock);
objp = kmem_cache_alloc_one(cachep);
spin_unlock(&cachep->spinlock);
}
}
#else
objp = kmem_cache_alloc_one(cachep);
#endif
local_irq_restore(save_flags);
return objp;
alloc_new_slab:
#ifdef CONFIG_SMP
spin_unlock(&cachep->spinlock);
alloc_new_slab_nolock:
#endif
local_irq_restore(save_flags);
if (kmem_cache_grow(cachep, flags))
/* Someone may have stolen our objs. Doesn't matter, we'll
* just come back here again.
*/
goto try_again;
return NULL;
}
/*
* Release an obj back to its cache. If the obj has a constructed
* state, it should be in this state _before_ it is released.
* - caller is responsible for the synchronization
*/
#if DEBUG
# define CHECK_NR(pg) \
do { \
if (!VALID_PAGE(pg)) { \
printk(KERN_ERR "kfree: out of range ptr %lxh.\n", \
(unsigned long)objp); \
BUG(); \
} \
} while (0)
# define CHECK_PAGE(page) \
do { \
CHECK_NR(page); \
if (!PageSlab(page)) { \
printk(KERN_ERR "kfree: bad ptr %lxh.\n", \
(unsigned long)objp); \
BUG(); \
} \
} while (0)
#else
# define CHECK_PAGE(pg) do { } while (0)
#endif
static inline void kmem_cache_free_one(kmem_cache_t *cachep, void *objp)
{
slab_t* slabp;
CHECK_PAGE(virt_to_page(objp));
/* reduces memory footprint
*
if (OPTIMIZE(cachep))
slabp = (void*)((unsigned long)objp&(~(PAGE_SIZE-1)));
else
*/
slabp = GET_PAGE_SLAB(virt_to_page(objp));
#if DEBUG
if (cachep->flags & SLAB_DEBUG_INITIAL)
/* Need to call the slab's constructor so the
* caller can perform a verify of its state (debugging).
* Called without the cache-lock held.
*/
cachep->ctor(objp, cachep, SLAB_CTOR_CONSTRUCTOR|SLAB_CTOR_VERIFY);
if (cachep->flags & SLAB_RED_ZONE) {
objp -= BYTES_PER_WORD;
if (xchg((unsigned long *)objp, RED_MAGIC1) != RED_MAGIC2)
/* Either write before start, or a double free. */
BUG();
if (xchg((unsigned long *)(objp+cachep->objsize -
BYTES_PER_WORD), RED_MAGIC1) != RED_MAGIC2)
/* Either write past end, or a double free. */
BUG();
}
if (cachep->flags & SLAB_POISON)
kmem_poison_obj(cachep, objp);
if (kmem_extra_free_checks(cachep, slabp, objp))
return;
#endif
{
unsigned int objnr = (objp-slabp->s_mem)/cachep->objsize;
slab_bufctl(slabp)[objnr] = slabp->free;
slabp->free = objnr;
}
STATS_DEC_ACTIVE(cachep);
/* fixup slab chains */
{
int inuse = slabp->inuse;
if (unlikely(!--slabp->inuse)) {
/* Was partial or full, now empty. */
list_del(&slabp->list);
list_add(&slabp->list, &cachep->slabs_free);
} else if (unlikely(inuse == cachep->num)) {
/* Was full. */
list_del(&slabp->list);
list_add(&slabp->list, &cachep->slabs_partial);
}
}
}
#ifdef CONFIG_SMP
static inline void __free_block (kmem_cache_t* cachep,
void** objpp, int len)
{
for ( ; len > 0; len--, objpp++)
kmem_cache_free_one(cachep, *objpp);
}
static void free_block (kmem_cache_t* cachep, void** objpp, int len)
{
spin_lock(&cachep->spinlock);
__free_block(cachep, objpp, len);
spin_unlock(&cachep->spinlock);
}
#endif
/*
* __kmem_cache_free
* called with disabled ints
*/
static inline void __kmem_cache_free (kmem_cache_t *cachep, void* objp)
{
#ifdef CONFIG_SMP
cpucache_t *cc = cc_data(cachep);
CHECK_PAGE(virt_to_page(objp));
if (cc) {
int batchcount;
if (cc->avail < cc->limit) {
STATS_INC_FREEHIT(cachep);
cc_entry(cc)[cc->avail++] = objp;
return;
}
STATS_INC_FREEMISS(cachep);
batchcount = cachep->batchcount;
cc->avail -= batchcount;
free_block(cachep,
&cc_entry(cc)[cc->avail],batchcount);
cc_entry(cc)[cc->avail++] = objp;
return;
} else {
free_block(cachep, &objp, 1);
}
#else
kmem_cache_free_one(cachep, objp);
#endif
}
/**
* kmem_cache_alloc - Allocate an object
* @cachep: The cache to allocate from.
* @flags: See kmalloc().
*
* Allocate an object from this cache. The flags are only relevant
* if the cache has no available objects.
*/
void * kmem_cache_alloc (kmem_cache_t *cachep, int flags)
{
return __kmem_cache_alloc(cachep, flags);
}
/**
* kmalloc - allocate memory
* @size: how many bytes of memory are required.
* @flags: the type of memory to allocate.
*
* kmalloc is the normal method of allocating memory
* in the kernel.
*
* The @flags argument may be one of:
*
* %GFP_USER - Allocate memory on behalf of user. May sleep.
*
* %GFP_KERNEL - Allocate normal kernel ram. May sleep.
*
* %GFP_ATOMIC - Allocation will not sleep. Use inside interrupt handlers.
*
* Additionally, the %GFP_DMA flag may be set to indicate the memory
* must be suitable for DMA. This can mean different things on different
* platforms. For example, on i386, it means that the memory must come
* from the first 16MB.
*/
void * kmalloc (size_t size, int flags)
{
cache_sizes_t *csizep = cache_sizes;
for (; csizep->cs_size; csizep++) {
if (size > csizep->cs_size)
continue;
return __kmem_cache_alloc(flags & GFP_DMA ?
csizep->cs_dmacachep : csizep->cs_cachep, flags);
}
return NULL;
}
/**
* kmem_cache_free - Deallocate an object
* @cachep: The cache the allocation was from.
* @objp: The previously allocated object.
*
* Free an object which was previously allocated from this
* cache.
*/
void kmem_cache_free (kmem_cache_t *cachep, void *objp)
{
unsigned long flags;
#if DEBUG
CHECK_PAGE(virt_to_page(objp));
if (cachep != GET_PAGE_CACHE(virt_to_page(objp)))
BUG();
#endif
local_irq_save(flags);
__kmem_cache_free(cachep, objp);
local_irq_restore(flags);
}
/**
* kfree - free previously allocated memory
* @objp: pointer returned by kmalloc.
*
* Don't free memory not originally allocated by kmalloc()
* or you will run into trouble.
*/
void kfree (const void *objp)
{
kmem_cache_t *c;
unsigned long flags;
if (!objp)
return;
local_irq_save(flags);
CHECK_PAGE(virt_to_page(objp));
c = GET_PAGE_CACHE(virt_to_page(objp));
__kmem_cache_free(c, (void*)objp);
local_irq_restore(flags);
}
unsigned int kmem_cache_size(kmem_cache_t *cachep)
{
#if DEBUG
if (cachep->flags & SLAB_RED_ZONE)
return (cachep->objsize - 2*BYTES_PER_WORD);
#endif
return cachep->objsize;
}
kmem_cache_t * kmem_find_general_cachep (size_t size, int gfpflags)
{
cache_sizes_t *csizep = cache_sizes;
/* This function could be moved to the header file, and
* made inline so consumers can quickly determine what
* cache pointer they require.
*/
for ( ; csizep->cs_size; csizep++) {
if (size > csizep->cs_size)
continue;
break;
}
return (gfpflags & GFP_DMA) ? csizep->cs_dmacachep : csizep->cs_cachep;
}
#ifdef CONFIG_SMP
/* called with cache_chain_sem acquired. */
static int kmem_tune_cpucache (kmem_cache_t* cachep, int limit, int batchcount)
{
ccupdate_struct_t new;
int i;
/*
* These are admin-provided, so we are more graceful.
*/
if (limit < 0)
return -EINVAL;
if (batchcount < 0)
return -EINVAL;
if (batchcount > limit)
return -EINVAL;
if (limit != 0 && !batchcount)
return -EINVAL;
memset(&new.new,0,sizeof(new.new));
if (limit) {
for (i = 0; i< smp_num_cpus; i++) {
cpucache_t* ccnew;
ccnew = kmalloc(sizeof(void*)*limit+
sizeof(cpucache_t), GFP_KERNEL);
if (!ccnew)
goto oom;
ccnew->limit = limit;
ccnew->avail = 0;
new.new[cpu_logical_map(i)] = ccnew;
}
}
new.cachep = cachep;
spin_lock_irq(&cachep->spinlock);
cachep->batchcount = batchcount;
spin_unlock_irq(&cachep->spinlock);
smp_call_function_all_cpus(do_ccupdate_local, (void *)&new);
for (i = 0; i < smp_num_cpus; i++) {
cpucache_t* ccold = new.new[cpu_logical_map(i)];
if (!ccold)
continue;
local_irq_disable();
free_block(cachep, cc_entry(ccold), ccold->avail);
local_irq_enable();
kfree(ccold);
}
return 0;
oom:
for (i--; i >= 0; i--)
kfree(new.new[cpu_logical_map(i)]);
return -ENOMEM;
}
static void enable_cpucache (kmem_cache_t *cachep)
{
int err;
int limit;
/* FIXME: optimize */
if (cachep->objsize > PAGE_SIZE)
return;
if (cachep->objsize > 1024)
limit = 60;
else if (cachep->objsize > 256)
limit = 124;
else
limit = 252;
err = kmem_tune_cpucache(cachep, limit, limit/2);
if (err)
printk(KERN_ERR "enable_cpucache failed for %s, error %d.\n",
cachep->name, -err);
}
static void enable_all_cpucaches (void)
{
struct list_head* p;
down(&cache_chain_sem);
p = &cache_cache.next;
do {
kmem_cache_t* cachep = list_entry(p, kmem_cache_t, next);
enable_cpucache(cachep);
p = cachep->next.next;
} while (p != &cache_cache.next);
up(&cache_chain_sem);
}
#endif
/**
* kmem_cache_reap - Reclaim memory from caches.
* @gfp_mask: the type of memory required.
*
* Called from do_try_to_free_pages() and __alloc_pages()
*/
int kmem_cache_reap (int gfp_mask)
{
slab_t *slabp;
kmem_cache_t *searchp;
kmem_cache_t *best_cachep;
unsigned int best_pages;
unsigned int best_len;
unsigned int scan;
int ret = 0;
if (gfp_mask & __GFP_WAIT)
down(&cache_chain_sem);
else
if (down_trylock(&cache_chain_sem))
return 0;
scan = REAP_SCANLEN;
best_len = 0;
best_pages = 0;
best_cachep = NULL;
searchp = clock_searchp;
do {
unsigned int pages;
struct list_head* p;
unsigned int full_free;
/* It's safe to test this without holding the cache-lock. */
if (searchp->flags & SLAB_NO_REAP)
goto next;
spin_lock_irq(&searchp->spinlock);
if (searchp->growing)
goto next_unlock;
if (searchp->dflags & DFLGS_GROWN) {
searchp->dflags &= ~DFLGS_GROWN;
goto next_unlock;
}
#ifdef CONFIG_SMP
{
cpucache_t *cc = cc_data(searchp);
if (cc && cc->avail) {
__free_block(searchp, cc_entry(cc), cc->avail);
cc->avail = 0;
}
}
#endif
full_free = 0;
p = searchp->slabs_free.next;
while (p != &searchp->slabs_free) {
slabp = list_entry(p, slab_t, list);
#if DEBUG
if (slabp->inuse)
BUG();
#endif
full_free++;
p = p->next;
}
/*
* Try to avoid slabs with constructors and/or
* more than one page per slab (as it can be difficult
* to get high orders from gfp()).
*/
pages = full_free * (1<<searchp->gfporder);
if (searchp->ctor)
pages = (pages*4+1)/5;
if (searchp->gfporder)
pages = (pages*4+1)/5;
if (pages > best_pages) {
best_cachep = searchp;
best_len = full_free;
best_pages = pages;
if (pages >= REAP_PERFECT) {
clock_searchp = list_entry(searchp->next.next,
kmem_cache_t,next);
goto perfect;
}
}
next_unlock:
spin_unlock_irq(&searchp->spinlock);
next:
searchp = list_entry(searchp->next.next,kmem_cache_t,next);
} while (--scan && searchp != clock_searchp);
clock_searchp = searchp;
if (!best_cachep)
/* couldn't find anything to reap */
goto out;
spin_lock_irq(&best_cachep->spinlock);
perfect:
/* free only 50% of the free slabs */
best_len = (best_len + 1)/2;
for (scan = 0; scan < best_len; scan++) {
struct list_head *p;
if (best_cachep->growing)
break;
p = best_cachep->slabs_free.prev;
if (p == &best_cachep->slabs_free)
break;
slabp = list_entry(p,slab_t,list);
#if DEBUG
if (slabp->inuse)
BUG();
#endif
list_del(&slabp->list);
STATS_INC_REAPED(best_cachep);
/* Safe to drop the lock. The slab is no longer linked to the
* cache.
*/
spin_unlock_irq(&best_cachep->spinlock);
kmem_slab_destroy(best_cachep, slabp);
spin_lock_irq(&best_cachep->spinlock);
}
spin_unlock_irq(&best_cachep->spinlock);
ret = scan * (1 << best_cachep->gfporder);
out:
up(&cache_chain_sem);
return ret;
}
#ifdef CONFIG_PROC_FS
static void *s_start(struct seq_file *m, loff_t *pos)
{
loff_t n = *pos;
struct list_head *p;
down(&cache_chain_sem);
if (!n)
return (void *)1;
p = &cache_cache.next;
while (--n) {
p = p->next;
if (p == &cache_cache.next)
return NULL;
}
return list_entry(p, kmem_cache_t, next);
}
static void *s_next(struct seq_file *m, void *p, loff_t *pos)
{
kmem_cache_t *cachep = p;
++*pos;
if (p == (void *)1)
return &cache_cache;
cachep = list_entry(cachep->next.next, kmem_cache_t, next);
return cachep == &cache_cache ? NULL : cachep;
}
static void s_stop(struct seq_file *m, void *p)
{
up(&cache_chain_sem);
}
static int s_show(struct seq_file *m, void *p)
{
kmem_cache_t *cachep = p;
struct list_head *q;
slab_t *slabp;
unsigned long active_objs;
unsigned long num_objs;
unsigned long active_slabs = 0;
unsigned long num_slabs;
const char *name;
if (p == (void*)1) {
/*
* Output format version, so at least we can change it
* without _too_ many complaints.
*/
seq_puts(m, "slabinfo - version: 1.1"
#if STATS
" (statistics)"
#endif
#ifdef CONFIG_SMP
" (SMP)"
#endif
"\n");
return 0;
}
spin_lock_irq(&cachep->spinlock);
active_objs = 0;
num_slabs = 0;
list_for_each(q,&cachep->slabs_full) {
slabp = list_entry(q, slab_t, list);
if (slabp->inuse != cachep->num)
BUG();
active_objs += cachep->num;
active_slabs++;
}
list_for_each(q,&cachep->slabs_partial) {
slabp = list_entry(q, slab_t, list);
if (slabp->inuse == cachep->num || !slabp->inuse)
BUG();
active_objs += slabp->inuse;
active_slabs++;
}
list_for_each(q,&cachep->slabs_free) {
slabp = list_entry(q, slab_t, list);
if (slabp->inuse)
BUG();
num_slabs++;
}
num_slabs+=active_slabs;
num_objs = num_slabs*cachep->num;
name = cachep->name;
{
char tmp;
mm_segment_t old_fs;
old_fs = get_fs();
set_fs(KERNEL_DS);
if (__get_user(tmp, name))
name = "broken";
set_fs(old_fs);
}
seq_printf(m, "%-17s %6lu %6lu %6u %4lu %4lu %4u",
name, active_objs, num_objs, cachep->objsize,
active_slabs, num_slabs, (1<<cachep->gfporder));
#if STATS
{
unsigned long errors = cachep->errors;
unsigned long high = cachep->high_mark;
unsigned long grown = cachep->grown;
unsigned long reaped = cachep->reaped;
unsigned long allocs = cachep->num_allocations;
seq_printf(m, " : %6lu %7lu %5lu %4lu %4lu",
high, allocs, grown, reaped, errors);
}
#endif
#ifdef CONFIG_SMP
{
cpucache_t *cc = cc_data(cachep);
unsigned int batchcount = cachep->batchcount;
unsigned int limit;
if (cc)
limit = cc->limit;
else
limit = 0;
seq_printf(m, " : %4u %4u",
limit, batchcount);
}
#endif
#if STATS && defined(CONFIG_SMP)
{
unsigned long allochit = atomic_read(&cachep->allochit);
unsigned long allocmiss = atomic_read(&cachep->allocmiss);
unsigned long freehit = atomic_read(&cachep->freehit);
unsigned long freemiss = atomic_read(&cachep->freemiss);
seq_printf(m, " : %6lu %6lu %6lu %6lu",
allochit, allocmiss, freehit, freemiss);
}
#endif
spin_unlock_irq(&cachep->spinlock);
seq_putc(m, '\n');
return 0;
}
/**
* slabinfo_op - iterator that generates /proc/slabinfo
*
* Output layout:
* cache-name
* num-active-objs
* total-objs
* object size
* num-active-slabs
* total-slabs
* num-pages-per-slab
* + further values on SMP and with statistics enabled
*/
struct seq_operations slabinfo_op = {
start: s_start,
next: s_next,
stop: s_stop,
show: s_show
};
#define MAX_SLABINFO_WRITE 128
/**
* slabinfo_write - SMP tuning for the slab allocator
* @file: unused
* @buffer: user buffer
* @count: data len
* @data: unused
*/
ssize_t slabinfo_write(struct file *file, const char *buffer,
size_t count, loff_t *ppos)
{
#ifdef CONFIG_SMP
char kbuf[MAX_SLABINFO_WRITE+1], *tmp;
int limit, batchcount, res;
struct list_head *p;
if (count > MAX_SLABINFO_WRITE)
return -EINVAL;
if (copy_from_user(&kbuf, buffer, count))
return -EFAULT;
kbuf[MAX_SLABINFO_WRITE] = '\0';
tmp = strchr(kbuf, ' ');
if (!tmp)
return -EINVAL;
*tmp = '\0';
tmp++;
limit = simple_strtol(tmp, &tmp, 10);
while (*tmp == ' ')
tmp++;
batchcount = simple_strtol(tmp, &tmp, 10);
/* Find the cache in the chain of caches. */
down(&cache_chain_sem);
res = -EINVAL;
list_for_each(p,&cache_chain) {
kmem_cache_t *cachep = list_entry(p, kmem_cache_t, next);
if (!strcmp(cachep->name, kbuf)) {
res = kmem_tune_cpucache(cachep, limit, batchcount);
break;
}
}
up(&cache_chain_sem);
if (res >= 0)
res = count;
return res;
#else
return -EINVAL;
#endif
}
#endif