Linux-2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 3060 insertions, 0 deletions

diff --git a/mm/slab.c b/mm/slab.c
new file mode 100644
index 000000000000..ec660d85ddd7
--- /dev/null
+++ b/mm/slab.c
@@ -0,0 +1,3060 @@
+/*
+ * linux/mm/slab.c
+ * Written by Mark Hemment, 1996/97.
+ * (markhe@nextd.demon.co.uk)
+ *
+ * kmem_cache_destroy() + some cleanup - 1999 Andrea Arcangeli
+ *
+ * Major cleanup, different bufctl logic, per-cpu arrays
+ *	(c) 2000 Manfred Spraul
+ *
+ * Cleanup, make the head arrays unconditional, preparation for NUMA
+ * 	(c) 2002 Manfred Spraul
+ *
+ * An implementation of the Slab Allocator as described in outline in;
+ *	UNIX Internals: The New Frontiers by Uresh Vahalia
+ *	Pub: Prentice Hall	ISBN 0-13-101908-2
+ * or with a little more detail in;
+ *	The Slab Allocator: An Object-Caching Kernel Memory Allocator
+ *	Jeff Bonwick (Sun Microsystems).
+ *	Presented at: USENIX Summer 1994 Technical Conference
+ *
+ * The memory is organized in caches, one cache for each object type.
+ * (e.g. inode_cache, dentry_cache, buffer_head, vm_area_struct)
+ * Each cache consists out of many slabs (they are small (usually one
+ * page long) and always contiguous), and each slab contains multiple
+ * initialized objects.
+ *
+ * This means, that your constructor is used only for newly allocated
+ * slabs and you must pass objects with the same intializations to
+ * kmem_cache_free.
+ *
+ * Each cache can only support one memory type (GFP_DMA, GFP_HIGHMEM,
+ * normal). If you need a special memory type, then must create a new
+ * cache for that memory type.
+ *
+ * In order to reduce fragmentation, the slabs are sorted in 3 groups:
+ *   full slabs with 0 free objects
+ *   partial slabs
+ *   empty slabs with no allocated objects
+ *
+ * If partial slabs exist, then new allocations come from these slabs,
+ * otherwise from empty slabs or new slabs are allocated.
+ *
+ * kmem_cache_destroy() CAN CRASH if you try to allocate from the cache
+ * during kmem_cache_destroy(). The caller must prevent concurrent allocs.
+ *
+ * Each cache has a short per-cpu head array, most allocs
+ * and frees go into that array, and if that array overflows, then 1/2
+ * of the entries in the array are given back into the global cache.
+ * The head array is strictly LIFO and should improve the cache hit rates.
+ * On SMP, it additionally reduces the spinlock operations.
+ *
+ * The c_cpuarray may not be read with enabled local interrupts - 
+ * it's changed with a smp_call_function().
+ *
+ * SMP synchronization:
+ *  constructors and destructors are called without any locking.
+ *  Several members in kmem_cache_t and struct slab never change, they
+ *	are accessed without any locking.
+ *  The per-cpu arrays are never accessed from the wrong cpu, no locking,
+ *  	and local interrupts are disabled so slab code is preempt-safe.
+ *  The non-constant members are protected with a per-cache irq spinlock.
+ *
+ * Many thanks to Mark Hemment, who wrote another per-cpu slab patch
+ * in 2000 - many ideas in the current implementation are derived from
+ * his patch.
+ *
+ * Further notes from the original documentation:
+ *
+ * 11 April '97.  Started multi-threading - markhe
+ *	The global cache-chain is protected by the semaphore 'cache_chain_sem'.
+ *	The sem is only needed when accessing/extending the cache-chain, which
+ *	can never happen inside an interrupt (kmem_cache_create(),
+ *	kmem_cache_shrink() and kmem_cache_reap()).
+ *
+ *	At present, each engine can be growing a cache.  This should be blocked.
+ *
+ */
+
+#include	<linux/config.h>
+#include	<linux/slab.h>
+#include	<linux/mm.h>
+#include	<linux/swap.h>
+#include	<linux/cache.h>
+#include	<linux/interrupt.h>
+#include	<linux/init.h>
+#include	<linux/compiler.h>
+#include	<linux/seq_file.h>
+#include	<linux/notifier.h>
+#include	<linux/kallsyms.h>
+#include	<linux/cpu.h>
+#include	<linux/sysctl.h>
+#include	<linux/module.h>
+#include	<linux/rcupdate.h>
+
+#include	<asm/uaccess.h>
+#include	<asm/cacheflush.h>
+#include	<asm/tlbflush.h>
+#include	<asm/page.h>
+
+/*
+ * DEBUG	- 1 for kmem_cache_create() to honour; SLAB_DEBUG_INITIAL,
+ *		  SLAB_RED_ZONE & SLAB_POISON.
+ *		  0 for faster, smaller code (especially in the critical paths).
+ *
+ * STATS	- 1 to collect stats for /proc/slabinfo.
+ *		  0 for faster, smaller code (especially in the critical paths).
+ *
+ * FORCED_DEBUG	- 1 enables SLAB_RED_ZONE and SLAB_POISON (if possible)
+ */
+
+#ifdef CONFIG_DEBUG_SLAB
+#define	DEBUG		1
+#define	STATS		1
+#define	FORCED_DEBUG	1
+#else
+#define	DEBUG		0
+#define	STATS		0
+#define	FORCED_DEBUG	0
+#endif
+
+
+/* Shouldn't this be in a header file somewhere? */
+#define	BYTES_PER_WORD		sizeof(void *)
+
+#ifndef cache_line_size
+#define cache_line_size()	L1_CACHE_BYTES
+#endif
+
+#ifndef ARCH_KMALLOC_MINALIGN
+/*
+ * Enforce a minimum alignment for the kmalloc caches.
+ * Usually, the kmalloc caches are cache_line_size() aligned, except when
+ * DEBUG and FORCED_DEBUG are enabled, then they are BYTES_PER_WORD aligned.
+ * Some archs want to perform DMA into kmalloc caches and need a guaranteed
+ * alignment larger than BYTES_PER_WORD. ARCH_KMALLOC_MINALIGN allows that.
+ * Note that this flag disables some debug features.
+ */
+#define ARCH_KMALLOC_MINALIGN 0
+#endif
+
+#ifndef ARCH_SLAB_MINALIGN
+/*
+ * Enforce a minimum alignment for all caches.
+ * Intended for archs that get misalignment faults even for BYTES_PER_WORD
+ * aligned buffers. Includes ARCH_KMALLOC_MINALIGN.
+ * If possible: Do not enable this flag for CONFIG_DEBUG_SLAB, it disables
+ * some debug features.
+ */
+#define ARCH_SLAB_MINALIGN 0
+#endif
+
+#ifndef ARCH_KMALLOC_FLAGS
+#define ARCH_KMALLOC_FLAGS SLAB_HWCACHE_ALIGN
+#endif
+
+/* Legal flag mask for kmem_cache_create(). */
+#if DEBUG
+# define CREATE_MASK	(SLAB_DEBUG_INITIAL | SLAB_RED_ZONE | \
+			 SLAB_POISON | SLAB_HWCACHE_ALIGN | \
+			 SLAB_NO_REAP | SLAB_CACHE_DMA | \
+			 SLAB_MUST_HWCACHE_ALIGN | SLAB_STORE_USER | \
+			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
+			 SLAB_DESTROY_BY_RCU)
+#else
+# define CREATE_MASK	(SLAB_HWCACHE_ALIGN | SLAB_NO_REAP | \
+			 SLAB_CACHE_DMA | SLAB_MUST_HWCACHE_ALIGN | \
+			 SLAB_RECLAIM_ACCOUNT | SLAB_PANIC | \
+			 SLAB_DESTROY_BY_RCU)
+#endif
+
+/*
+ * kmem_bufctl_t:
+ *
+ * Bufctl's are used for linking objs within a slab
+ * linked offsets.
+ *
+ * This implementation relies on "struct page" for locating the cache &
+ * slab an object belongs to.
+ * This allows the bufctl structure to be small (one int), but limits
+ * the number of objects a slab (not a cache) can contain when off-slab
+ * bufctls are used. The limit is the size of the largest general cache
+ * that does not use off-slab slabs.
+ * For 32bit archs with 4 kB pages, is this 56.
+ * This is not serious, as it is only for large objects, when it is unwise
+ * to have too many per slab.
+ * Note: This limit can be raised by introducing a general cache whose size
+ * is less than 512 (PAGE_SIZE<<3), but greater than 256.
+ */
+
+#define BUFCTL_END	(((kmem_bufctl_t)(~0U))-0)
+#define BUFCTL_FREE	(((kmem_bufctl_t)(~0U))-1)
+#define	SLAB_LIMIT	(((kmem_bufctl_t)(~0U))-2)
+
+/* Max number of objs-per-slab for caches which use off-slab slabs.
+ * Needed to avoid a possible looping condition in cache_grow().
+ */
+static unsigned long offslab_limit;
+
+/*
+ * struct slab
+ *
+ * Manages the objs in a slab. Placed either at the beginning of mem allocated
+ * for a slab, or allocated from an general cache.
+ * Slabs are chained into three list: fully used, partial, fully free slabs.
+ */
+struct slab {
+	struct list_head	list;
+	unsigned long		colouroff;
+	void			*s_mem;		/* including colour offset */
+	unsigned int		inuse;		/* num of objs active in slab */
+	kmem_bufctl_t		free;
+};
+
+/*
+ * struct slab_rcu
+ *
+ * slab_destroy on a SLAB_DESTROY_BY_RCU cache uses this structure to
+ * arrange for kmem_freepages to be called via RCU.  This is useful if
+ * we need to approach a kernel structure obliquely, from its address
+ * obtained without the usual locking.  We can lock the structure to
+ * stabilize it and check it's still at the given address, only if we
+ * can be sure that the memory has not been meanwhile reused for some
+ * other kind of object (which our subsystem's lock might corrupt).
+ *
+ * rcu_read_lock before reading the address, then rcu_read_unlock after
+ * taking the spinlock within the structure expected at that address.
+ *
+ * We assume struct slab_rcu can overlay struct slab when destroying.
+ */
+struct slab_rcu {
+	struct rcu_head		head;
+	kmem_cache_t		*cachep;
+	void			*addr;
+};
+
+/*
+ * struct array_cache
+ *
+ * Per cpu structures
+ * Purpose:
+ * - LIFO ordering, to hand out cache-warm objects from _alloc
+ * - reduce the number of linked list operations
+ * - reduce spinlock operations
+ *
+ * The limit is stored in the per-cpu structure to reduce the data cache
+ * footprint.
+ *
+ */
+struct array_cache {
+	unsigned int avail;
+	unsigned int limit;
+	unsigned int batchcount;
+	unsigned int touched;
+};
+
+/* bootstrap: The caches do not work without cpuarrays anymore,
+ * but the cpuarrays are allocated from the generic caches...
+ */
+#define BOOT_CPUCACHE_ENTRIES	1
+struct arraycache_init {
+	struct array_cache cache;
+	void * entries[BOOT_CPUCACHE_ENTRIES];
+};
+
+/*
+ * The slab lists of all objects.
+ * Hopefully reduce the internal fragmentation
+ * NUMA: The spinlock could be moved from the kmem_cache_t
+ * into this structure, too. Figure out what causes
+ * fewer cross-node spinlock operations.
+ */
+struct kmem_list3 {
+	struct list_head	slabs_partial;	/* partial list first, better asm code */
+	struct list_head	slabs_full;
+	struct list_head	slabs_free;
+	unsigned long	free_objects;
+	int		free_touched;
+	unsigned long	next_reap;
+	struct array_cache	*shared;
+};
+
+#define LIST3_INIT(parent) \
+	{ \
+		.slabs_full	= LIST_HEAD_INIT(parent.slabs_full), \
+		.slabs_partial	= LIST_HEAD_INIT(parent.slabs_partial), \
+		.slabs_free	= LIST_HEAD_INIT(parent.slabs_free) \
+	}
+#define list3_data(cachep) \
+	(&(cachep)->lists)
+
+/* NUMA: per-node */
+#define list3_data_ptr(cachep, ptr) \
+		list3_data(cachep)
+
+/*
+ * kmem_cache_t
+ *
+ * manages a cache.
+ */
+	
+struct kmem_cache_s {
+/* 1) per-cpu data, touched during every alloc/free */
+	struct array_cache	*array[NR_CPUS];
+	unsigned int		batchcount;
+	unsigned int		limit;
+/* 2) touched by every alloc & free from the backend */
+	struct kmem_list3	lists;
+	/* NUMA: kmem_3list_t	*nodelists[MAX_NUMNODES] */
+	unsigned int		objsize;
+	unsigned int	 	flags;	/* constant flags */
+	unsigned int		num;	/* # of objs per slab */
+	unsigned int		free_limit; /* upper limit of objects in the lists */
+	spinlock_t		spinlock;
+
+/* 3) cache_grow/shrink */
+	/* order of pgs per slab (2^n) */
+	unsigned int		gfporder;
+
+	/* force GFP flags, e.g. GFP_DMA */
+	unsigned int		gfpflags;
+
+	size_t			colour;		/* cache colouring range */
+	unsigned int		colour_off;	/* colour offset */
+	unsigned int		colour_next;	/* cache colouring */
+	kmem_cache_t		*slabp_cache;
+	unsigned int		slab_size;
+	unsigned int		dflags;		/* dynamic flags */
+
+	/* constructor func */
+	void (*ctor)(void *, kmem_cache_t *, unsigned long);
+
+	/* de-constructor func */
+	void (*dtor)(void *, kmem_cache_t *, unsigned long);
+
+/* 4) cache creation/removal */
+	const char		*name;
+	struct list_head	next;
+
+/* 5) statistics */
+#if STATS
+	unsigned long		num_active;
+	unsigned long		num_allocations;
+	unsigned long		high_mark;
+	unsigned long		grown;
+	unsigned long		reaped;
+	unsigned long 		errors;
+	unsigned long		max_freeable;
+	unsigned long		node_allocs;
+	atomic_t		allochit;
+	atomic_t		allocmiss;
+	atomic_t		freehit;
+	atomic_t		freemiss;
+#endif
+#if DEBUG
+	int			dbghead;
+	int			reallen;
+#endif
+};
+
+#define CFLGS_OFF_SLAB		(0x80000000UL)
+#define	OFF_SLAB(x)	((x)->flags & CFLGS_OFF_SLAB)
+
+#define BATCHREFILL_LIMIT	16
+/* Optimization question: fewer reaps means less 
+ * probability for unnessary cpucache drain/refill cycles.
+ *
+ * OTHO the cpuarrays can contain lots of objects,
+ * which could lock up otherwise freeable slabs.
+ */
+#define REAPTIMEOUT_CPUC	(2*HZ)
+#define REAPTIMEOUT_LIST3	(4*HZ)
+
+#if STATS
+#define	STATS_INC_ACTIVE(x)	((x)->num_active++)
+#define	STATS_DEC_ACTIVE(x)	((x)->num_active--)
+#define	STATS_INC_ALLOCED(x)	((x)->num_allocations++)
+#define	STATS_INC_GROWN(x)	((x)->grown++)
+#define	STATS_INC_REAPED(x)	((x)->reaped++)
+#define	STATS_SET_HIGH(x)	do { if ((x)->num_active > (x)->high_mark) \
+					(x)->high_mark = (x)->num_active; \
+				} while (0)
+#define	STATS_INC_ERR(x)	((x)->errors++)
+#define	STATS_INC_NODEALLOCS(x)	((x)->node_allocs++)
+#define	STATS_SET_FREEABLE(x, i) \
+				do { if ((x)->max_freeable < i) \
+					(x)->max_freeable = i; \
+				} while (0)
+
+#define STATS_INC_ALLOCHIT(x)	atomic_inc(&(x)->allochit)
+#define STATS_INC_ALLOCMISS(x)	atomic_inc(&(x)->allocmiss)
+#define STATS_INC_FREEHIT(x)	atomic_inc(&(x)->freehit)
+#define STATS_INC_FREEMISS(x)	atomic_inc(&(x)->freemiss)
+#else
+#define	STATS_INC_ACTIVE(x)	do { } while (0)
+#define	STATS_DEC_ACTIVE(x)	do { } while (0)
+#define	STATS_INC_ALLOCED(x)	do { } while (0)
+#define	STATS_INC_GROWN(x)	do { } while (0)
+#define	STATS_INC_REAPED(x)	do { } while (0)
+#define	STATS_SET_HIGH(x)	do { } while (0)
+#define	STATS_INC_ERR(x)	do { } while (0)
+#define	STATS_INC_NODEALLOCS(x)	do { } while (0)
+#define	STATS_SET_FREEABLE(x, i) \
+				do { } while (0)
+
+#define STATS_INC_ALLOCHIT(x)	do { } while (0)
+#define STATS_INC_ALLOCMISS(x)	do { } while (0)
+#define STATS_INC_FREEHIT(x)	do { } while (0)
+#define STATS_INC_FREEMISS(x)	do { } while (0)
+#endif
+
+#if DEBUG
+/* Magic nums for obj red zoning.
+ * Placed in the first word before and the first word after an obj.
+ */
+#define	RED_INACTIVE	0x5A2CF071UL	/* when obj is inactive */
+#define	RED_ACTIVE	0x170FC2A5UL	/* when obj is active */
+
+/* ...and for poisoning */
+#define	POISON_INUSE	0x5a	/* for use-uninitialised poisoning */
+#define POISON_FREE	0x6b	/* for use-after-free poisoning */
+#define	POISON_END	0xa5	/* end-byte of poisoning */
+
+/* memory layout of objects:
+ * 0		: objp
+ * 0 .. cachep->dbghead - BYTES_PER_WORD - 1: padding. This ensures that
+ * 		the end of an object is aligned with the end of the real
+ * 		allocation. Catches writes behind the end of the allocation.
+ * cachep->dbghead - BYTES_PER_WORD .. cachep->dbghead - 1:
+ * 		redzone word.
+ * cachep->dbghead: The real object.
+ * cachep->objsize - 2* BYTES_PER_WORD: redzone word [BYTES_PER_WORD long]
+ * cachep->objsize - 1* BYTES_PER_WORD: last caller address [BYTES_PER_WORD long]
+ */
+static int obj_dbghead(kmem_cache_t *cachep)
+{
+	return cachep->dbghead;
+}
+
+static int obj_reallen(kmem_cache_t *cachep)
+{
+	return cachep->reallen;
+}
+
+static unsigned long *dbg_redzone1(kmem_cache_t *cachep, void *objp)
+{
+	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
+	return (unsigned long*) (objp+obj_dbghead(cachep)-BYTES_PER_WORD);
+}
+
+static unsigned long *dbg_redzone2(kmem_cache_t *cachep, void *objp)
+{
+	BUG_ON(!(cachep->flags & SLAB_RED_ZONE));
+	if (cachep->flags & SLAB_STORE_USER)
+		return (unsigned long*) (objp+cachep->objsize-2*BYTES_PER_WORD);
+	return (unsigned long*) (objp+cachep->objsize-BYTES_PER_WORD);
+}
+
+static void **dbg_userword(kmem_cache_t *cachep, void *objp)
+{
+	BUG_ON(!(cachep->flags & SLAB_STORE_USER));
+	return (void**)(objp+cachep->objsize-BYTES_PER_WORD);
+}
+
+#else
+
+#define obj_dbghead(x)			0
+#define obj_reallen(cachep)		(cachep->objsize)
+#define dbg_redzone1(cachep, objp)	({BUG(); (unsigned long *)NULL;})
+#define dbg_redzone2(cachep, objp)	({BUG(); (unsigned long *)NULL;})
+#define dbg_userword(cachep, objp)	({BUG(); (void **)NULL;})
+
+#endif
+
+/*
+ * Maximum size of an obj (in 2^order pages)
+ * and absolute limit for the gfp order.
+ */
+#if defined(CONFIG_LARGE_ALLOCS)
+#define	MAX_OBJ_ORDER	13	/* up to 32Mb */
+#define	MAX_GFP_ORDER	13	/* up to 32Mb */
+#elif defined(CONFIG_MMU)
+#define	MAX_OBJ_ORDER	5	/* 32 pages */
+#define	MAX_GFP_ORDER	5	/* 32 pages */
+#else
+#define	MAX_OBJ_ORDER	8	/* up to 1Mb */
+#define	MAX_GFP_ORDER	8	/* up to 1Mb */
+#endif
+
+/*
+ * Do not go above this order unless 0 objects fit into the slab.
+ */
+#define	BREAK_GFP_ORDER_HI	1
+#define	BREAK_GFP_ORDER_LO	0
+static int slab_break_gfp_order = BREAK_GFP_ORDER_LO;
+
+/* Macros for storing/retrieving the cachep and or slab from the
+ * global 'mem_map'. These are used to find the slab an obj belongs to.
+ * With kfree(), these are used to find the cache which an obj belongs to.
+ */
+#define	SET_PAGE_CACHE(pg,x)  ((pg)->lru.next = (struct list_head *)(x))
+#define	GET_PAGE_CACHE(pg)    ((kmem_cache_t *)(pg)->lru.next)
+#define	SET_PAGE_SLAB(pg,x)   ((pg)->lru.prev = (struct list_head *)(x))
+#define	GET_PAGE_SLAB(pg)     ((struct slab *)(pg)->lru.prev)
+
+/* These are the default caches for kmalloc. Custom caches can have other sizes. */
+struct cache_sizes malloc_sizes[] = {
+#define CACHE(x) { .cs_size = (x) },
+#include <linux/kmalloc_sizes.h>
+	CACHE(ULONG_MAX)
+#undef CACHE
+};
+EXPORT_SYMBOL(malloc_sizes);
+
+/* Must match cache_sizes above. Out of line to keep cache footprint low. */
+struct cache_names {
+	char *name;
+	char *name_dma;
+};
+
+static struct cache_names __initdata cache_names[] = {
+#define CACHE(x) { .name = "size-" #x, .name_dma = "size-" #x "(DMA)" },
+#include <linux/kmalloc_sizes.h>
+	{ NULL, }
+#undef CACHE
+};
+
+static struct arraycache_init initarray_cache __initdata =
+	{ { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
+static struct arraycache_init initarray_generic =
+	{ { 0, BOOT_CPUCACHE_ENTRIES, 1, 0} };
+
+/* internal cache of cache description objs */
+static kmem_cache_t cache_cache = {
+	.lists		= LIST3_INIT(cache_cache.lists),
+	.batchcount	= 1,
+	.limit		= BOOT_CPUCACHE_ENTRIES,
+	.objsize	= sizeof(kmem_cache_t),
+	.flags		= SLAB_NO_REAP,
+	.spinlock	= SPIN_LOCK_UNLOCKED,
+	.name		= "kmem_cache",
+#if DEBUG
+	.reallen	= sizeof(kmem_cache_t),
+#endif
+};
+
+/* Guard access to the cache-chain. */
+static struct semaphore	cache_chain_sem;
+static struct list_head cache_chain;
+
+/*
+ * vm_enough_memory() looks at this to determine how many
+ * slab-allocated pages are possibly freeable under pressure
+ *
+ * SLAB_RECLAIM_ACCOUNT turns this on per-slab
+ */
+atomic_t slab_reclaim_pages;
+EXPORT_SYMBOL(slab_reclaim_pages);
+
+/*
+ * chicken and egg problem: delay the per-cpu array allocation
+ * until the general caches are up.
+ */
+static enum {
+	NONE,
+	PARTIAL,
+	FULL
+} g_cpucache_up;
+
+static DEFINE_PER_CPU(struct work_struct, reap_work);
+
+static void free_block(kmem_cache_t* cachep, void** objpp, int len);
+static void enable_cpucache (kmem_cache_t *cachep);
+static void cache_reap (void *unused);
+
+static inline void **ac_entry(struct array_cache *ac)
+{
+	return (void**)(ac+1);
+}
+
+static inline struct array_cache *ac_data(kmem_cache_t *cachep)
+{
+	return cachep->array[smp_processor_id()];
+}
+
+static inline kmem_cache_t *kmem_find_general_cachep(size_t size, int gfpflags)
+{
+	struct cache_sizes *csizep = malloc_sizes;
+
+#if DEBUG
+	/* This happens if someone tries to call
+ 	* kmem_cache_create(), or __kmalloc(), before
+ 	* the generic caches are initialized.
+ 	*/
+	BUG_ON(csizep->cs_cachep == NULL);
+#endif
+	while (size > csizep->cs_size)
+		csizep++;
+
+	/*
+	 * Really subtile: The last entry with cs->cs_size==ULONG_MAX
+	 * has cs_{dma,}cachep==NULL. Thus no special case
+	 * for large kmalloc calls required.
+	 */
+	if (unlikely(gfpflags & GFP_DMA))
+		return csizep->cs_dmacachep;
+	return csizep->cs_cachep;
+}
+
+/* Cal the num objs, wastage, and bytes left over for a given slab size. */
+static void cache_estimate(unsigned long gfporder, size_t size, size_t align,
+		 int flags, size_t *left_over, unsigned int *num)
+{
+	int i;
+	size_t wastage = PAGE_SIZE<<gfporder;
+	size_t extra = 0;
+	size_t base = 0;
+
+	if (!(flags & CFLGS_OFF_SLAB)) {
+		base = sizeof(struct slab);
+		extra = sizeof(kmem_bufctl_t);
+	}
+	i = 0;
+	while (i*size + ALIGN(base+i*extra, align) <= wastage)
+		i++;
+	if (i > 0)
+		i--;
+
+	if (i > SLAB_LIMIT)
+		i = SLAB_LIMIT;
+
+	*num = i;
+	wastage -= i*size;
+	wastage -= ALIGN(base+i*extra, align);
+	*left_over = wastage;
+}
+
+#define slab_error(cachep, msg) __slab_error(__FUNCTION__, cachep, msg)
+
+static void __slab_error(const char *function, kmem_cache_t *cachep, char *msg)
+{
+	printk(KERN_ERR "slab error in %s(): cache `%s': %s\n",
+		function, cachep->name, msg);
+	dump_stack();
+}
+
+/*
+ * Initiate the reap timer running on the target CPU.  We run at around 1 to 2Hz
+ * via the workqueue/eventd.
+ * Add the CPU number into the expiration time to minimize the possibility of
+ * the CPUs getting into lockstep and contending for the global cache chain
+ * lock.
+ */
+static void __devinit start_cpu_timer(int cpu)
+{
+	struct work_struct *reap_work = &per_cpu(reap_work, cpu);
+
+	/*
+	 * When this gets called from do_initcalls via cpucache_init(),
+	 * init_workqueues() has already run, so keventd will be setup
+	 * at that time.
+	 */
+	if (keventd_up() && reap_work->func == NULL) {
+		INIT_WORK(reap_work, cache_reap, NULL);
+		schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
+	}
+}
+
+static struct array_cache *alloc_arraycache(int cpu, int entries,
+						int batchcount)
+{
+	int memsize = sizeof(void*)*entries+sizeof(struct array_cache);
+	struct array_cache *nc = NULL;
+
+	if (cpu != -1) {
+		kmem_cache_t *cachep;
+		cachep = kmem_find_general_cachep(memsize, GFP_KERNEL);
+		if (cachep)
+			nc = kmem_cache_alloc_node(cachep, cpu_to_node(cpu));
+	}
+	if (!nc)
+		nc = kmalloc(memsize, GFP_KERNEL);
+	if (nc) {
+		nc->avail = 0;
+		nc->limit = entries;
+		nc->batchcount = batchcount;
+		nc->touched = 0;
+	}
+	return nc;
+}
+
+static int __devinit cpuup_callback(struct notifier_block *nfb,
+				  unsigned long action, void *hcpu)
+{
+	long cpu = (long)hcpu;
+	kmem_cache_t* cachep;
+
+	switch (action) {
+	case CPU_UP_PREPARE:
+		down(&cache_chain_sem);
+		list_for_each_entry(cachep, &cache_chain, next) {
+			struct array_cache *nc;
+
+			nc = alloc_arraycache(cpu, cachep->limit, cachep->batchcount);
+			if (!nc)
+				goto bad;
+
+			spin_lock_irq(&cachep->spinlock);
+			cachep->array[cpu] = nc;
+			cachep->free_limit = (1+num_online_cpus())*cachep->batchcount
+						+ cachep->num;
+			spin_unlock_irq(&cachep->spinlock);
+
+		}
+		up(&cache_chain_sem);
+		break;
+	case CPU_ONLINE:
+		start_cpu_timer(cpu);
+		break;
+#ifdef CONFIG_HOTPLUG_CPU
+	case CPU_DEAD:
+		/* fall thru */
+	case CPU_UP_CANCELED:
+		down(&cache_chain_sem);
+
+		list_for_each_entry(cachep, &cache_chain, next) {
+			struct array_cache *nc;
+
+			spin_lock_irq(&cachep->spinlock);
+			/* cpu is dead; no one can alloc from it. */
+			nc = cachep->array[cpu];
+			cachep->array[cpu] = NULL;
+			cachep->free_limit -= cachep->batchcount;
+			free_block(cachep, ac_entry(nc), nc->avail);
+			spin_unlock_irq(&cachep->spinlock);
+			kfree(nc);
+		}
+		up(&cache_chain_sem);
+		break;
+#endif
+	}
+	return NOTIFY_OK;
+bad:
+	up(&cache_chain_sem);
+	return NOTIFY_BAD;
+}
+
+static struct notifier_block cpucache_notifier = { &cpuup_callback, NULL, 0 };
+
+/* Initialisation.
+ * Called after the gfp() functions have been enabled, and before smp_init().
+ */
+void __init kmem_cache_init(void)
+{
+	size_t left_over;
+	struct cache_sizes *sizes;
+	struct cache_names *names;
+
+	/*
+	 * Fragmentation resistance on low memory - only use bigger
+	 * page orders on machines with more than 32MB of memory.
+	 */
+	if (num_physpages > (32 << 20) >> PAGE_SHIFT)
+		slab_break_gfp_order = BREAK_GFP_ORDER_HI;
+
+	
+	/* Bootstrap is tricky, because several objects are allocated
+	 * from caches that do not exist yet:
+	 * 1) initialize the cache_cache cache: it contains the kmem_cache_t
+	 *    structures of all caches, except cache_cache itself: cache_cache
+	 *    is statically allocated.
+	 *    Initially an __init data area is used for the head array, it's
+	 *    replaced with a kmalloc allocated array at the end of the bootstrap.
+	 * 2) Create the first kmalloc cache.
+	 *    The kmem_cache_t for the new cache is allocated normally. An __init
+	 *    data area is used for the head array.
+	 * 3) Create the remaining kmalloc caches, with minimally sized head arrays.
+	 * 4) Replace the __init data head arrays for cache_cache and the first
+	 *    kmalloc cache with kmalloc allocated arrays.
+	 * 5) Resize the head arrays of the kmalloc caches to their final sizes.
+	 */
+
+	/* 1) create the cache_cache */
+	init_MUTEX(&cache_chain_sem);
+	INIT_LIST_HEAD(&cache_chain);
+	list_add(&cache_cache.next, &cache_chain);
+	cache_cache.colour_off = cache_line_size();
+	cache_cache.array[smp_processor_id()] = &initarray_cache.cache;
+
+	cache_cache.objsize = ALIGN(cache_cache.objsize, cache_line_size());
+
+	cache_estimate(0, cache_cache.objsize, cache_line_size(), 0,
+				&left_over, &cache_cache.num);
+	if (!cache_cache.num)
+		BUG();
+
+	cache_cache.colour = left_over/cache_cache.colour_off;
+	cache_cache.colour_next = 0;
+	cache_cache.slab_size = ALIGN(cache_cache.num*sizeof(kmem_bufctl_t) +
+				sizeof(struct slab), cache_line_size());
+
+	/* 2+3) create the kmalloc caches */
+	sizes = malloc_sizes;
+	names = cache_names;
+
+	while (sizes->cs_size != ULONG_MAX) {
+		/* For performance, all the general caches are L1 aligned.
+		 * This should be particularly beneficial on SMP boxes, as it
+		 * eliminates "false sharing".
+		 * Note for systems short on memory removing the alignment will
+		 * allow tighter packing of the smaller caches. */
+		sizes->cs_cachep = kmem_cache_create(names->name,
+			sizes->cs_size, ARCH_KMALLOC_MINALIGN,
+			(ARCH_KMALLOC_FLAGS | SLAB_PANIC), NULL, NULL);
+
+		/* Inc off-slab bufctl limit until the ceiling is hit. */
+		if (!(OFF_SLAB(sizes->cs_cachep))) {
+			offslab_limit = sizes->cs_size-sizeof(struct slab);
+			offslab_limit /= sizeof(kmem_bufctl_t);
+		}
+
+		sizes->cs_dmacachep = kmem_cache_create(names->name_dma,
+			sizes->cs_size, ARCH_KMALLOC_MINALIGN,
+			(ARCH_KMALLOC_FLAGS | SLAB_CACHE_DMA | SLAB_PANIC),
+			NULL, NULL);
+
+		sizes++;
+		names++;
+	}
+	/* 4) Replace the bootstrap head arrays */
+	{
+		void * ptr;
+		
+		ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
+		local_irq_disable();
+		BUG_ON(ac_data(&cache_cache) != &initarray_cache.cache);
+		memcpy(ptr, ac_data(&cache_cache), sizeof(struct arraycache_init));
+		cache_cache.array[smp_processor_id()] = ptr;
+		local_irq_enable();
+	
+		ptr = kmalloc(sizeof(struct arraycache_init), GFP_KERNEL);
+		local_irq_disable();
+		BUG_ON(ac_data(malloc_sizes[0].cs_cachep) != &initarray_generic.cache);
+		memcpy(ptr, ac_data(malloc_sizes[0].cs_cachep),
+				sizeof(struct arraycache_init));
+		malloc_sizes[0].cs_cachep->array[smp_processor_id()] = ptr;
+		local_irq_enable();
+	}
+
+	/* 5) resize the head arrays to their final sizes */
+	{
+		kmem_cache_t *cachep;
+		down(&cache_chain_sem);
+		list_for_each_entry(cachep, &cache_chain, next)
+			enable_cpucache(cachep);
+		up(&cache_chain_sem);
+	}
+
+	/* Done! */
+	g_cpucache_up = FULL;
+
+	/* Register a cpu startup notifier callback
+	 * that initializes ac_data for all new cpus
+	 */
+	register_cpu_notifier(&cpucache_notifier);
+	
+
+	/* The reap timers are started later, with a module init call:
+	 * That part of the kernel is not yet operational.
+	 */
+}
+
+static int __init cpucache_init(void)
+{
+	int cpu;
+
+	/* 
+	 * Register the timers that return unneeded
+	 * pages to gfp.
+	 */
+	for (cpu = 0; cpu < NR_CPUS; cpu++) {
+		if (cpu_online(cpu))
+			start_cpu_timer(cpu);
+	}
+
+	return 0;
+}
+
+__initcall(cpucache_init);
+
+/*
+ * Interface to system's page allocator. No need to hold the cache-lock.
+ *
+ * If we requested dmaable memory, we will get it. Even if we
+ * did not request dmaable memory, we might get it, but that
+ * would be relatively rare and ignorable.
+ */
+static void *kmem_getpages(kmem_cache_t *cachep, unsigned int __nocast flags, int nodeid)
+{
+	struct page *page;
+	void *addr;
+	int i;
+
+	flags |= cachep->gfpflags;
+	if (likely(nodeid == -1)) {
+		page = alloc_pages(flags, cachep->gfporder);
+	} else {
+		page = alloc_pages_node(nodeid, flags, cachep->gfporder);
+	}
+	if (!page)
+		return NULL;
+	addr = page_address(page);
+
+	i = (1 << cachep->gfporder);
+	if (cachep->flags & SLAB_RECLAIM_ACCOUNT)
+		atomic_add(i, &slab_reclaim_pages);
+	add_page_state(nr_slab, i);
+	while (i--) {
+		SetPageSlab(page);
+		page++;
+	}
+	return addr;
+}
+
+/*
+ * Interface to system's page release.
+ */
+static void kmem_freepages(kmem_cache_t *cachep, void *addr)
+{
+	unsigned long i = (1<<cachep->gfporder);
+	struct page *page = virt_to_page(addr);
+	const unsigned long nr_freed = i;
+
+	while (i--) {
+		if (!TestClearPageSlab(page))
+			BUG();
+		page++;
+	}
+	sub_page_state(nr_slab, nr_freed);
+	if (current->reclaim_state)
+		current->reclaim_state->reclaimed_slab += nr_freed;
+	free_pages((unsigned long)addr, cachep->gfporder);
+	if (cachep->flags & SLAB_RECLAIM_ACCOUNT) 
+		atomic_sub(1<<cachep->gfporder, &slab_reclaim_pages);
+}
+
+static void kmem_rcu_free(struct rcu_head *head)
+{
+	struct slab_rcu *slab_rcu = (struct slab_rcu *) head;
+	kmem_cache_t *cachep = slab_rcu->cachep;
+
+	kmem_freepages(cachep, slab_rcu->addr);
+	if (OFF_SLAB(cachep))
+		kmem_cache_free(cachep->slabp_cache, slab_rcu);
+}
+
+#if DEBUG
+
+#ifdef CONFIG_DEBUG_PAGEALLOC
+static void store_stackinfo(kmem_cache_t *cachep, unsigned long *addr,
+				unsigned long caller)
+{
+	int size = obj_reallen(cachep);
+
+	addr = (unsigned long *)&((char*)addr)[obj_dbghead(cachep)];
+
+	if (size < 5*sizeof(unsigned long))
+		return;
+
+	*addr++=0x12345678;
+	*addr++=caller;
+	*addr++=smp_processor_id();
+	size -= 3*sizeof(unsigned long);
+	{
+		unsigned long *sptr = &caller;
+		unsigned long svalue;
+
+		while (!kstack_end(sptr)) {
+			svalue = *sptr++;
+			if (kernel_text_address(svalue)) {
+				*addr++=svalue;
+				size -= sizeof(unsigned long);
+				if (size <= sizeof(unsigned long))
+					break;
+			}
+		}
+
+	}
+	*addr++=0x87654321;
+}
+#endif
+
+static void poison_obj(kmem_cache_t *cachep, void *addr, unsigned char val)
+{
+	int size = obj_reallen(cachep);
+	addr = &((char*)addr)[obj_dbghead(cachep)];
+
+	memset(addr, val, size);
+	*(unsigned char *)(addr+size-1) = POISON_END;
+}
+
+static void dump_line(char *data, int offset, int limit)
+{
+	int i;
+	printk(KERN_ERR "%03x:", offset);
+	for (i=0;i<limit;i++) {
+		printk(" %02x", (unsigned char)data[offset+i]);
+	}
+	printk("\n");
+}
+#endif
+
+#if DEBUG
+
+static void print_objinfo(kmem_cache_t *cachep, void *objp, int lines)
+{
+	int i, size;
+	char *realobj;
+
+	if (cachep->flags & SLAB_RED_ZONE) {
+		printk(KERN_ERR "Redzone: 0x%lx/0x%lx.\n",
+			*dbg_redzone1(cachep, objp),
+			*dbg_redzone2(cachep, objp));
+	}
+
+	if (cachep->flags & SLAB_STORE_USER) {
+		printk(KERN_ERR "Last user: [<%p>]",
+				*dbg_userword(cachep, objp));
+		print_symbol("(%s)",
+				(unsigned long)*dbg_userword(cachep, objp));
+		printk("\n");
+	}
+	realobj = (char*)objp+obj_dbghead(cachep);
+	size = obj_reallen(cachep);
+	for (i=0; i<size && lines;i+=16, lines--) {
+		int limit;
+		limit = 16;
+		if (i+limit > size)
+			limit = size-i;
+		dump_line(realobj, i, limit);
+	}
+}
+
+static void check_poison_obj(kmem_cache_t *cachep, void *objp)
+{
+	char *realobj;
+	int size, i;
+	int lines = 0;
+
+	realobj = (char*)objp+obj_dbghead(cachep);
+	size = obj_reallen(cachep);
+
+	for (i=0;i<size;i++) {
+		char exp = POISON_FREE;
+		if (i == size-1)
+			exp = POISON_END;
+		if (realobj[i] != exp) {
+			int limit;
+			/* Mismatch ! */
+			/* Print header */
+			if (lines == 0) {
+				printk(KERN_ERR "Slab corruption: start=%p, len=%d\n",
+						realobj, size);
+				print_objinfo(cachep, objp, 0);
+			}
+			/* Hexdump the affected line */
+			i = (i/16)*16;
+			limit = 16;
+			if (i+limit > size)
+				limit = size-i;
+			dump_line(realobj, i, limit);
+			i += 16;
+			lines++;
+			/* Limit to 5 lines */
+			if (lines > 5)
+				break;
+		}
+	}
+	if (lines != 0) {
+		/* Print some data about the neighboring objects, if they
+		 * exist:
+		 */
+		struct slab *slabp = GET_PAGE_SLAB(virt_to_page(objp));
+		int objnr;
+
+		objnr = (objp-slabp->s_mem)/cachep->objsize;
+		if (objnr) {
+			objp = slabp->s_mem+(objnr-1)*cachep->objsize;
+			realobj = (char*)objp+obj_dbghead(cachep);
+			printk(KERN_ERR "Prev obj: start=%p, len=%d\n",
+						realobj, size);
+			print_objinfo(cachep, objp, 2);
+		}
+		if (objnr+1 < cachep->num) {
+			objp = slabp->s_mem+(objnr+1)*cachep->objsize;
+			realobj = (char*)objp+obj_dbghead(cachep);
+			printk(KERN_ERR "Next obj: start=%p, len=%d\n",
+						realobj, size);
+			print_objinfo(cachep, objp, 2);
+		}
+	}
+}
+#endif
+
+/* Destroy all the objs in a slab, and release the mem back to the system.
+ * Before calling the slab must have been unlinked from the cache.
+ * The cache-lock is not held/needed.
+ */
+static void slab_destroy (kmem_cache_t *cachep, struct slab *slabp)
+{
+	void *addr = slabp->s_mem - slabp->colouroff;
+
+#if DEBUG
+	int i;
+	for (i = 0; i < cachep->num; i++) {
+		void *objp = slabp->s_mem + cachep->objsize * i;
+
+		if (cachep->flags & SLAB_POISON) {
+#ifdef CONFIG_DEBUG_PAGEALLOC
+			if ((cachep->objsize%PAGE_SIZE)==0 && OFF_SLAB(cachep))
+				kernel_map_pages(virt_to_page(objp), cachep->objsize/PAGE_SIZE,1);
+			else
+				check_poison_obj(cachep, objp);
+#else
+			check_poison_obj(cachep, objp);
+#endif
+