[SLUB 1/3] SLUB core

Christoph Lameter
2007-03-07T02:35:08Z

SLUB core

Basic new slab allocator. See overview for details

Signed-off-by: Christoph Lameter <clameter@sgi.com>

Index: linux-2.6.21-rc2-mm1/fs/proc/proc_misc.c
===================================================================
--- linux-2.6.21-rc2-mm1.orig/fs/proc/proc_misc.c 2007-03-06 17:59:44.000000000 -0800
+++ linux-2.6.21-rc2-mm1/fs/proc/proc_misc.c 2007-03-06 18:03:49.000000000 -0800
@@ -399,6 +399,21 @@ static const struct file_operations proc
};
#endif

+#ifdef CONFIG_SLUB
+extern struct seq_operations slubinfo_op;
+static int slubinfo_open(struct inode *inode, struct file *file)
+{
+ return seq_open(file, &slubinfo_op);
+}
+static const struct file_operations proc_slubinfo_operations = {
+ .open = slubinfo_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = seq_release,
+};
+#endif
+
+
#ifdef CONFIG_SLAB
static int slabinfo_open(struct inode *inode, struct file *file)
{
@@ -789,6 +804,9 @@ void __init proc_misc_init(void)
#endif
create_seq_entry("stat", 0, &proc_stat_operations);
create_seq_entry("interrupts", 0, &proc_interrupts_operations);
+#ifdef CONFIG_SLUB
+ create_seq_entry("slubinfo",S_IWUSR|S_IRUGO,&proc_slubinfo_operations);
+#endif
#ifdef CONFIG_SLAB
create_seq_entry("slabinfo",S_IWUSR|S_IRUGO,&proc_slabinfo_operations);
#ifdef CONFIG_DEBUG_SLAB_LEAK
Index: linux-2.6.21-rc2-mm1/include/linux/mm_types.h
===================================================================
--- linux-2.6.21-rc2-mm1.orig/include/linux/mm_types.h 2007-03-06 17:59:44.000000000 -0800
+++ linux-2.6.21-rc2-mm1/include/linux/mm_types.h 2007-03-06 18:03:49.000000000 -0800
@@ -19,10 +19,16 @@ struct page {
unsigned long flags; /* Atomic flags, some possibly
* updated asynchronously */
atomic_t _count; /* Usage count, see below. */
- atomic_t _mapcount; /* Count of ptes mapped in mms,
+ union {
+ atomic_t _mapcount; /* Count of ptes mapped in mms,
* to show when page is mapped
* & limit reverse map searches.
*/
+ struct { /* SLUB uses */
+ short unsigned int inuse;
+ short unsigned int offset;
+ };
+ };
union {
struct {
unsigned long private; /* Mapping-private opaque data:
@@ -43,8 +49,15 @@ struct page {
#if NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS
spinlock_t ptl;
#endif
+ struct { /* SLUB uses */
+ struct page *first_page; /* Compound pages */
+ struct kmem_cache *slab; /* Pointer to slab */
+ };
+ };
+ union {
+ pgoff_t index; /* Our offset within mapping. */
+ void *freelist; /* SLUB: pointer to free object */
};
- pgoff_t index; /* Our offset within mapping. */
struct list_head lru; /* Pageout list, eg. active_list
* protected by zone->lru_lock !
*/
Index: linux-2.6.21-rc2-mm1/include/linux/slab.h
===================================================================
--- linux-2.6.21-rc2-mm1.orig/include/linux/slab.h 2007-03-06 17:59:44.000000000 -0800
+++ linux-2.6.21-rc2-mm1/include/linux/slab.h 2007-03-06 18:03:49.000000000 -0800
@@ -32,6 +32,7 @@ typedef struct kmem_cache kmem_cache_t _
#define SLAB_PANIC 0x00040000UL /* Panic if kmem_cache_create() fails */
#define SLAB_DESTROY_BY_RCU 0x00080000UL /* Defer freeing slabs to RCU */
#define SLAB_MEM_SPREAD 0x00100000UL /* Spread some memory over cpuset */
+#define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */

/* Flags passed to a constructor functions */
#define SLAB_CTOR_CONSTRUCTOR 0x001UL /* If not set, then deconstructor */
@@ -95,9 +96,14 @@ static inline void *kcalloc(size_t n, si
* the appropriate general cache at compile time.
*/

-#ifdef CONFIG_SLAB
+#if defined(CONFIG_SLAB) || defined(CONFIG_SLUB)
+#ifdef CONFIG_SLUB
+#include <linux/slub_def.h>
+#else
#include <linux/slab_def.h>
+#endif /* !CONFIG_SLUB */
#else
+
/*
* Fallback definitions for an allocator not wanting to provide
* its own optimized kmalloc definitions (like SLOB).
Index: linux-2.6.21-rc2-mm1/include/linux/slub_def.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.21-rc2-mm1/include/linux/slub_def.h 2007-03-06 18:03:49.000000000 -0800
@@ -0,0 +1,168 @@
+#ifndef _LINUX_SLUB_DEF_H
+#define _LINUX_SLUB_DEF_H
+
+/*
+ * SLUB : A Slab allocator without object queues.
+ *
+ * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
+ */
+#include <linux/types.h>
+#include <linux/gfp.h>
+#include <linux/workqueue.h>
+
+struct kmem_cache_node {
+ spinlock_t list_lock; /* Protect partial list and nr_partial */
+ unsigned long nr_partial;
+ atomic_long_t nr_slabs;
+ struct list_head partial;
+};
+
+/*
+ * Slab cache management.
+ */
+struct kmem_cache {
+ int offset; /* Free pointer offset. */
+ unsigned int order;
+ unsigned long flags;
+ int size; /* Total size of an object */
+ int objects; /* Number of objects in slab */
+ struct kmem_cache_node local_node;
+ int refcount; /* Refcount for destroy */
+ void (*ctor)(void *, struct kmem_cache *, unsigned long);
+ void (*dtor)(void *, struct kmem_cache *, unsigned long);
+
+ int objsize; /* The size of an object that is in a chunk */
+ int inuse; /* Used portion of the chunk */
+ const char *name; /* Name (only for display!) */
+ char *aliases; /* Slabs merged into this one */
+ struct list_head list; /* List of slabs */
+#ifdef CONFIG_SMP
+ struct mutex flushing;
+ atomic_t cpu_slabs; /*
+ * if >0 then flusher is scheduled. Also used
+ * to count remaining cpus if flushing
+ */
+ struct delayed_work flush;
+#endif
+#ifdef CONFIG_NUMA
+ struct kmem_cache_node *node[MAX_NUMNODES];
+#endif
+ struct page *cpu_slab[NR_CPUS];
+};
+
+/*
+ * Kmalloc subsystem.
+ */
+#define KMALLOC_SHIFT_LOW 3
+
+#define KMALLOC_SHIFT_HIGH 18
+
+#if L1_CACHE_BYTES <= 64
+#define KMALLOC_EXTRAS 2
+#define KMALLOC_EXTRA
+#else
+#define KMALLOC_EXTRAS 0
+#endif
+
+#define KMALLOC_NR_CACHES (KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW \
+ + 1 + KMALLOC_EXTRAS)
+/*
+ * We keep the general caches in an array of slab caches that are used for
+ * 2^x bytes of allocations.
+ */
+extern struct kmem_cache kmalloc_caches[KMALLOC_NR_CACHES];
+
+/*
+ * Sorry that the following has to be that ugly but some versions of GCC
+ * have trouble with constant propagation and loops.
+ */
+static inline int kmalloc_index(int size)
+{
+ if (size <= 8) return 3;
+ if (size <= 16) return 4;
+ if (size <= 32) return 5;
+ if (size <= 64) return 6;
+#ifdef KMALLOC_EXTRA
+ if (size <= 96) return KMALLOC_SHIFT_HIGH + 1;
+#endif
+ if (size <= 128) return 7;
+#ifdef KMALLOC_EXTRA
+ if (size <= 192) return KMALLOC_SHIFT_HIGH + 2;
+#endif
+ if (size <= 256) return 8;
+ if (size <= 512) return 9;
+ if (size <= 1024) return 10;
+ if (size <= 2048) return 11;
+ if (size <= 4096) return 12;
+ if (size <= 8 * 1024) return 13;
+ if (size <= 16 * 1024) return 14;
+ if (size <= 32 * 1024) return 15;
+ if (size <= 64 * 1024) return 16;
+ if (size <= 128 * 1024) return 17;
+ if (size <= 256 * 1024) return 18;
+ return -1;
+}
+
+/*
+ * Find the slab cache for a given combination of allocation flags and size.
+ *
+ * This ought to end up with a global pointer to the right cache
+ * in kmalloc_caches.
+ */
+static inline struct kmem_cache *kmalloc_slab(size_t size)
+{
+ int index = kmalloc_index(size) - KMALLOC_SHIFT_LOW;
+
+ if (index < 0) {
+ /*
+ * Generate a link failure. Would be great if we could
+ * do something to stop the compile here.
+ */
+ extern void __kmalloc_size_too_large(void);
+ __kmalloc_size_too_large();
+ }
+ return &kmalloc_caches[index];
+}
+
+#ifdef CONFIG_ZONE_DMA
+#define SLUB_DMA __GFP_DMA
+#else
+/* Disable SLAB functionality */
+#define SLUB_DMA 0
+#endif
+
+static inline void *kmalloc(size_t size, gfp_t flags)
+{
+ if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
+ struct kmem_cache *s = kmalloc_slab(size);
+
+ return kmem_cache_alloc(s, flags);
+ } else
+ return __kmalloc(size, flags);
+}
+
+static inline void *kzalloc(size_t size, gfp_t flags)
+{
+ if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
+ struct kmem_cache *s = kmalloc_slab(size);
+
+ return kmem_cache_zalloc(s, flags);
+ } else
+ return __kzalloc(size, flags);
+}
+
+#ifdef CONFIG_NUMA
+extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
+
+static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
+{
+ if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) {
+ struct kmem_cache *s = kmalloc_slab(size);
+
+ return kmem_cache_alloc_node(s, flags, node);
+ } else
+ return __kmalloc_node(size, flags, node);
+}
+#endif
+
+#endif /* _LINUX_SLUB_DEF_H */
Index: linux-2.6.21-rc2-mm1/init/Kconfig
===================================================================
--- linux-2.6.21-rc2-mm1.orig/init/Kconfig 2007-03-06 17:59:44.000000000 -0800
+++ linux-2.6.21-rc2-mm1/init/Kconfig 2007-03-06 18:03:49.000000000 -0800
@@ -481,15 +481,6 @@ config SHMEM
option replaces shmem and tmpfs with the much simpler ramfs code,
which may be appropriate on small systems without swap.

-config SLAB
- default y
- bool "Use full SLAB allocator" if (EMBEDDED && !SMP && !SPARSEMEM)
- help
- Disabling this replaces the advanced SLAB allocator and
- kmalloc support with the drastically simpler SLOB allocator.
- SLOB is more space efficient but does not scale well and is
- more susceptible to fragmentation.
-
config VM_EVENT_COUNTERS
default y
bool "Enable VM event counters for /proc/vmstat" if EMBEDDED
@@ -537,6 +528,46 @@ config RCU_TRACE
Say Y here if you want to enable RCU tracing
Say N if you are unsure.

+choice
+ prompt "Choose SLAB allocator"
+ default SLAB
+ help
+ This option allows to select a slab allocator.
+
+config SLAB
+ bool "SLAB"
+ help
+ The regular slab allocator that is established and known to work
+ well in all environments. It organizes chache hot objects in
+ per cpu and per node queues. SLAB is the default choice for
+ slab allocator.
+
+config SLUB
+ depends on EXPERIMENTAL
+ bool "SLUB (Unqueued Allocator)"
+ help
+ SLUB is a slab allocator that minimizes cache line usage
+ instead of managing queues of cached objects (SLAB approach).
+ Per cpu caching is realized using slabs of objects instead
+ of queues of objects. SLUB can use memory in the most efficient
+ way and has enhanced diagnostics.
+
+config SLOB
+#
+# SLOB cannot support SMP because SLAB_DESTROY_BY_RCU does not work
+# properly.
+#
+ depends on EMBEDDED && !SMP && !SPARSEMEM
+ bool "SLOB (Simple Allocator)"
+ help
+ SLOB replaces the SLAB allocator with a drastically simpler
+ allocator. SLOB is more space efficient that SLAB but does not
+ scale well (single lock for all operations) and is more susceptible
+ to fragmentation. SLOB it is a great choice to reduce
+ memory usage and code size.
+
+endchoice
+
endmenu # General setup

config RT_MUTEXES
@@ -552,10 +583,6 @@ config BASE_SMALL
default 0 if BASE_FULL
default 1 if !BASE_FULL

-config SLOB
- default !SLAB
- bool
-
menu "Loadable module support"

config MODULES
Index: linux-2.6.21-rc2-mm1/mm/Makefile
===================================================================
--- linux-2.6.21-rc2-mm1.orig/mm/Makefile 2007-03-06 17:59:44.000000000 -0800
+++ linux-2.6.21-rc2-mm1/mm/Makefile 2007-03-06 18:03:49.000000000 -0800
@@ -26,6 +26,7 @@ obj-$(CONFIG_TMPFS_POSIX_ACL) += shmem_a
obj-$(CONFIG_TINY_SHMEM) += tiny-shmem.o
obj-$(CONFIG_SLOB) += slob.o
obj-$(CONFIG_SLAB) += slab.o
+obj-$(CONFIG_SLUB) += slub.o
obj-$(CONFIG_MEMORY_HOTPLUG) += memory_hotplug.o
obj-$(CONFIG_FS_XIP) += filemap_xip.o
obj-$(CONFIG_MIGRATION) += migrate.o
Index: linux-2.6.21-rc2-mm1/mm/slub.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6.21-rc2-mm1/mm/slub.c 2007-03-06 18:05:36.000000000 -0800
@@ -0,0 +1,2253 @@
+/*
+ * SLUB: A slab allocator that limits cache line use instead of queuing
+ * objects in per cpu and per node lists.
+ *
+ * The allocator synchronizes using per slab locks and only
+ * uses a centralized lock to manage a pool of partial slabs.
+ *
+ * (C) 2007 SGI, Christoph Lameter <clameter@sgi.com>
+ */
+
+#include <linux/mm.h>
+#include <linux/module.h>
+#include <linux/bit_spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/mempolicy.h>
+#include <linux/ctype.h>
+
+/*
+ * Lock order:
+ * 1. slab_lock(page)
+ * 2. slab->list_lock
+ *
+ * SLUB assigns one slab for allocation to each processor.
+ * Allocations only occur from these slabs called cpu slabs.
+ *
+ * If a cpu slab exists then a workqueue thread checks every 10
+ * seconds if the cpu slab is still in use. The cpu slab is pushed back
+ * to the list if inactive [only needed for SMP].
+ *
+ * Slabs with free elements are kept on a partial list.
+ * There is no list for full slabs. If an object in a full slab is
+ * freed then the slab will show up again on the partial lists.
+ * Otherwise there is no need to track full slabs (but we keep a counter).
+ *
+ * Slabs are freed when they become empty. Teardown and setup is
+ * minimal so we rely on the page allocators per cpu caches for
+ * fast frees and allocs.
+ *
+ * Overloading of page flags that are otherwise used for LRU management.
+ *
+ * PageActive The slab is used as a cpu cache. Allocations
+ * may be performed from the slab. The slab is not
+ * on a partial list.
+ *
+ * PageReferenced The per cpu slab was used recently. This is used
+ * to push back per cpu slabs if they are unused
+ * for a longer time period.
+ *
+ * PageError Slab requires special handling due to debug
+ * options set or a single page slab. This moves
+ * slab handling out of the fast path.
+ */
+
+/*
+ * Flags from the regular SLAB that SLUB does not support:
+ */
+#define SLUB_UNIMPLEMENTED (SLAB_DEBUG_INITIAL)
+
+#define DEBUG_DEFAULT_FLAGS (SLAB_DEBUG_FREE | SLAB_RED_ZONE | \
+ SLAB_POISON)
+/*
+ * Set of flags that will prevent slab merging
+ */
+#define SLUB_NEVER_MERGE (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER | \
+ SLAB_TRACE)
+
+#define SLUB_MERGE_SAME (SLAB_DEBUG_FREE | SLAB_DESTROY_BY_RCU | \
+ SLAB_RECLAIM_ACCOUNT | SLAB_CACHE_DMA)
+
+#ifndef ARCH_KMALLOC_MINALIGN
+#define ARCH_KMALLOC_MINALIGN sizeof(void *)
+#endif
+
+#ifndef ARCH_SLAB_MINALIGN
+#define ARCH_SLAB_MINALIGN sizeof(void *)
+#endif
+
+static int kmem_size = sizeof(struct kmem_cache);
+
+#ifdef CONFIG_SMP
+static struct notifier_block slab_notifier;
+#endif
+
+static enum {
+ DOWN, /* No slab functionality available */
+ PARTIAL, /* kmem_cache_open() works but kmalloc does not */
+ UP /* Everything works */
+} slab_state = DOWN;
+
+int slab_is_available(void) {
+ return slab_state == UP;
+}
+
+/* A list of all slab caches on the system */
+static DECLARE_RWSEM(slub_lock);
+LIST_HEAD(slab_caches);
+
+/********************************************************************
+ * Core slab cache functions
+ *******************************************************************/
+
+struct kmem_cache_node *get_node(struct kmem_cache *s, int node)
+{
+#ifdef CONFIG_NUMA
+ return s->node[node];
+#else
+ return &s->local_node;
+#endif
+}
+
+/*
+ * Object debugging
+ */
+static void print_section(char *text, u8 *addr, unsigned int length)
+{
+ int i, offset;
+ int newline = 1;
+ char ascii[17];
+
+ if (length > 128)
+ length = 128;
+ ascii[16] = 0;
+
+ for (i = 0; i < length; i++) {
+ if (newline) {
+ printk(KERN_ERR "%10s %p: ", text, addr + i);
+ newline = 0;
+ }
+ printk(" %02x", addr[i]);
+ offset = i % 16;
+ ascii[offset] = isgraph(addr[i]) ? addr[i] : '.';
+ if (offset == 15) {
+ printk(" %s\n",ascii);
+ newline = 1;
+ }
+ }
+ if (!newline) {
+ i %= 16;
+ while (i < 16) {
+ printk(" ");
+ ascii[i] = ' ';
+ i++;
+ }
+ printk(" %s\n", ascii);
+ }
+}
+
+/*
+ * Slow version of get and set free pointer.
+ *
+ * This requires touching the cache lines of kmem_cache.
+ * The offset can also be obtained from the page. In that
+ * case it is in the cacheline that we already need to touch.
+ */
+static void *get_freepointer(struct kmem_cache *s, void *object)
+{
+ return *(void **)(object + s->offset);
+}
+
+static void set_freepointer(struct kmem_cache *s, void *object, void *fp)
+{
+ *(void **)(object + s->offset) = fp;
+}
+
+/*
+ * Tracking user of a slab.
+ */
+static void *get_track(struct kmem_cache *s, void *object, int alloc)
+{
+ void **p = object + s->inuse + sizeof(void *);
+
+ return p[alloc];
+}
+
+static void set_track(struct kmem_cache *s, void *object,
+ int alloc, void *addr)
+{
+ void **p = object + s->inuse + sizeof(void *);
+
+ p[alloc] = addr;
+}
+
+#define set_tracking(__s, __o, __a) set_track(__s, __o, __a, \
+ __builtin_return_address(0))
+
+static void init_tracking(struct kmem_cache *s, void *object)
+{
+ if (s->flags & SLAB_STORE_USER) {
+ set_track(s, object, 0, NULL);
+ set_track(s, object, 1, NULL);
+ }
+}
+
+static void print_trailer(struct kmem_cache *s, u8 *p)
+{
+ unsigned int off; /* Offset of last byte */
+
+ if (s->offset)
+ off = s->offset + sizeof(void *);
+ else
+ off = s->inuse;
+
+ if (s->flags & SLAB_RED_ZONE)
+ print_section("Redzone", p + s->objsize,
+ s->inuse - s->objsize);
+
+ printk(KERN_ERR "FreePointer %p: %p\n",
+ p + s->offset,
+ get_freepointer(s, p));
+
+ if (s->flags & SLAB_STORE_USER) {
+ printk(KERN_ERR "Last Allocate from %p. Last Free from %p\n",
+ get_track(s, p, 0), get_track(s, p, 1));
+ off += 2 * sizeof(void *);
+ }
+
+ if (off != s->size)
+ /* Beginning of the filler is the free pointer */
+ print_section("Filler", p + off, s->size - off);
+}
+
+static void object_err(struct kmem_cache *s, struct page *page,
+ u8 *object, char *reason)
+{
+ u8 *addr = page_address(page);
+
+ printk(KERN_ERR "*** SLUB: %s in %s@%p Slab %p\n",
+ reason, s->name, object, page);
+ printk(KERN_ERR " offset=%u flags=%04lx inuse=%u freelist=%p\n",
+ (int)(object - addr), page->flags, page->inuse, page->freelist);
+ if (object > addr + 16)
+ print_section("Bytes b4", object - 16, 16);
+ print_section("Object", object, s->objsize);
+ print_trailer(s, object);
+ dump_stack();
+}
+
+static void init_object(struct kmem_cache *s, void *object, int active)
+{
+ u8 *p = object;
+
+ if (s->objects == 1)
+ return;
+
+ if (s->flags & SLAB_POISON) {
+ memset(p, POISON_FREE, s->objsize -1);
+ p[s->objsize -1] = POISON_END;
+ }
+
+ if (s->flags & SLAB_RED_ZONE)
+ memset(p + s->objsize,
+ active ? RED_ACTIVE : RED_INACTIVE,
+ s->inuse - s->objsize);
+}
+
+static int check_bytes(u8 *start, unsigned int value, unsigned int bytes)
+{
+ while (bytes) {
+ if (*start != (u8)value)
+ return 0;
+ start++;
+ bytes--;
+ }
+ return 1;
+}
+
+
+static int check_valid_pointer(struct kmem_cache *s, struct page *page,
+ void *object)
+{
+ void *base;
+
+ if (!object)
+ return 1;
+
+ base = page_address(page);
+ if (object < base || object >= base + s->objects * s->size ||
+ (object - base) % s->size) {
+ return 0;
+ }
+
+ return 1;
+}
+
+/*
+ * Object layout:
+ *
+ * object address
+ * Bytes of the object to be managed.
+ * If the freepointer may overlay the object then the free
+ * pointer is the first word of the object.
+ * Poisoning uses 0x6b (POISON_FREE) and the last byte is
+ * 0xa5 (POISON_END)
+ *
+ * object + s->objsize
+ * Padding to reach word boundary. This is also used for Redzoning.
+ * Padding is extended to word size if Redzoning is enabled
+ * and objsize == inuse.
+ * We fill with 0x71 (RED_INACTIVE) for inactive objects and with
+ * 0xa5 (RED_ACTIVE) for objects in use.
+ *
+ * object + s->inuse
+ * A. Free pointer (if we cannot overwrite object on free)
+ * B. Tracking data for SLAB_STORE_USER
+ * C. Padding to reach required alignment boundary
+ * Padding is done using 0x5a (POISON_INUSE)
+ *
+ * object + s->size
+ *
+ * If slabcaches are merged then the objsize and inuse boundaries are to be ignored.
+ * And therefore no slab options that rely on these boundaries may be used with
+ * merged slabcaches.
+ */
+
+static int check_pad_bytes(struct kmem_cache *s, struct page *page, u8 *p)
+{
+ unsigned long off = s->inuse; /* The end of info */
+
+ if (s->offset)
+ /* Freepointer is placed after the object. */
+ off += sizeof(void *);
+
+ if (s->flags & SLAB_STORE_USER)
+ /* We also have user information there */
+ off += 2 * sizeof(void *);
+
+ if (s->size == off)
+ return 1;
+
+ if (check_bytes(p + off, POISON_INUSE, s->size - off))
+ return 1;
+
+ object_err(s, page, p, "Object padding check fails");
+ return 0;
+}
+
+static int check_object(struct kmem_cache *s, struct page *page,
+ void *object, int active)
+{
+ u8 *p = object;
+ u8 *endobject = object + s->objsize;
+
+ /* Single object slabs do not get policed */
+ if (s->objects == 1)
+ return 1;
+
+ if (s->flags & SLAB_RED_ZONE) {
+ if (!check_bytes(endobject,
+ active ? RED_ACTIVE : RED_INACTIVE,
+ s->inuse - s->objsize)) {
+ object_err(s, page, object,
+ active ? "Redzone Active check fails" :
+ "Redzone Inactive check fails");
+ return 0;
+ }
+ } else
+ if ((s->flags & SLAB_POISON) &&
+ s->objsize < s->inuse &&
+ !check_bytes(endobject, POISON_INUSE, s->inuse - s->objsize))
+ object_err(s, page, p, "Alignment padding check fails");
+
+ if (s->flags & SLAB_POISON) {
+ if (!active && (!check_bytes(p, POISON_FREE, s->objsize - 1) ||
+ p[s->objsize -1] != POISON_END)) {
+ object_err(s, page, p, "Poison");
+ return 0;
+ }
+ if (!check_pad_bytes(s, page, p))
+ return 0;
+ }
+
+ if (!s->offset && active)
+ /*
+ * Object and freepointer overlap. Cannot check
+ * freepointer while object is allocated.
+ */
+ return 1;
+
+ /* Check free pointer validity */
+ if (!check_valid_pointer(s, page, get_freepointer(s, p))) {
+ object_err(s, page, p, "Freepointer corrupt");
+ /*
+ * No choice but to zap it. This may cause
+ * another error because the object count
+ * is now wrong.
+ */
+ set_freepointer(s, p, NULL);
+ return 0;
+ }
+ return 1;
+}
+
+static int check_slab(struct kmem_cache *s, struct page *page)
+{
+ if (!PageSlab(page)) {
+ printk(KERN_CRIT "SLUB: %s Not a valid slab page @%p flags=%lx"
+ " mapping=%p count=%d \n",
+ s->name, page, page->flags, page->mapping,
+ page_count(page));
+ return 0;
+ }
+ if (page->offset * sizeof(void *) != s->offset) {
+ printk(KERN_CRIT "SLUB: %s Corrupted offset %lu in slab @%p"
+ " flags=%lx mapping=%p count=%d\n",
+ s->name,
+ (unsigned long)(page->offset * sizeof(void *)),
+ page,
+ page->flags,
+ page->mapping,
+ page_count(page));
+ return 0;
+ }
+ if (page->inuse > s->objects) {
+ printk(KERN_CRIT "SLUB: %s Inuse %u > max %u in slab page @%p"
+ " flags=%lx mapping=%p count=%d\n",
+ s->name, page->inuse, s->objects, page, page->flags,
+ page->mapping, page_count(page));
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * Determine if a certain object on a page is on the freelist and
+ * therefore free. Must hold the slab lock for cpu slabs to
+ * guarantee that the chains are consistent.
+ */
+static int on_freelist(struct kmem_cache *s, struct page *page, void *search)
+{
+ int nr = 0;
+ void *fp = page->freelist;
+ void *object = NULL;
+
+ if (s->objects == 1)
+ return 0;
+
+ while (fp && nr <= s->objects) {
+ if (fp == search)
+ return 1;
+ if (!check_valid_pointer(s, page, fp)) {
+ if (object) {
+ object_err(s, page, object, "Freechain corrupt");
+ set_freepointer(s, object, NULL);
+ break;
+ } else {
+ printk(KERN_ERR "SLUB: %s slab %p freepointer %p corrupted.\n",
+ s->name, page, fp);
+ dump_stack();
+ page->freelist = NULL;
+ page->inuse = s->objects;
+ return 0;
+ }
+ break;
+ }
+ object = fp;
+ fp = get_freepointer(s, object);
+ nr++;
+ }
+
+ if (page->inuse != s->objects - nr) {
+ printk(KERN_CRIT "slab %s: page %p wrong object count."
+ " counter is %d but counted were %d\n",
+ s->name, page, page->inuse,
+ s->objects - nr);
+ page->inuse = s->objects - nr;
+ }
+ return 0;
+}
+
+static int alloc_object_checks(struct kmem_cache *s, struct page *page,
+ void *object)
+{
+ if (!check_slab(s, page))
+ goto bad;
+
+ if (object && !on_freelist(s, page, object)) {
+ printk(KERN_ERR "SLAB: %s Object %p@%p already allocated.\n",
+ s->name, object, page);
+ goto dump;
+ }
+
+ if (!check_valid_pointer(s, page, object)) {
+ object_err(s, page, object, "Freelist Pointer check fails");
+ goto dump;
+ }
+
+ if (!object)
+ return 1;
+
+ if (!check_object(s, page, object, 0))
+ goto bad;
+ init_object(s, object, 1);
+
+ if (s->flags & SLAB_TRACE) {
+ printk("SLUB-Trace %s alloc object=%p slab=%p inuse=%d"
+ " freelist=%p\n",
+ s->name, object, page, page->inuse,
+ page->freelist);
+ dump_stack();
+ }
+ return 1;
+dump:
+ dump_stack();
+bad:
+ /* Mark slab full */
+ page->inuse = s->objects;
+ page->freelist = NULL;
+ return 0;
+}
+
+static int free_object_checks(struct kmem_cache *s, struct page *page, void *object)
+{
+ if (!check_slab(s, page)) {
+ goto fail;
+ }
+
+ if (!check_valid_pointer(s, page, object)) {
+ printk(KERN_ERR "SLUB: %s slab %p invalid object pointer %p\n",
+ s->name, page, object);
+ goto fail;
+ }
+
+ if (on_freelist(s, page, object)) {
+ printk(KERN_CRIT "SLUB: %s slab %p object %p already free.\n",
+ s->name, page, object);
+ goto fail;
+ }
+
+ if (!check_object(s, page, object, 1))
+ return 0;
+
+ if (unlikely(s != page->slab)) {
+ if (!PageSlab(page))
+ printk(KERN_CRIT "slab_free %s size %d: attempt to"
+ "free object(%p) outside of slab.\n",
+ s->name, s->size, object);
+ else
+ if (!page->slab)
+ printk(KERN_CRIT
+ "slab_free : no slab(NULL) for object %p.\n",
+ object);
+ else
+ printk(KERN_CRIT "slab_free %s(%d): object at %p"
+ " belongs to slab %s(%d)\n",
+ s->name, s->size, object,
+ page->slab->name, page->slab->size);
+ goto fail;
+ }
+ if (s->flags & SLAB_TRACE) {
+ printk("SLUB-Trace %s free object=%p slab=%p"
+ "inuse=%d freelist=%p\n",
+ s->name, object, page, page->inuse,
+ page->freelist);
+ print_section("SLUB-Trace", object, s->objsize);
+ dump_stack();
+ }
+ init_object(s, object, 0);
+ return 1;
+fail:
+ dump_stack();
+ return 0;
+}
+
+/*
+ * Slab allocation and freeing
+ */
+static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ struct page * page;
+ int pages = 1 << s->order;
+
+ if (s->order)
+ flags |= __GFP_COMP;
+
+ if (s->flags & SLUB_DMA)
+ flags |= GFP_DMA;
+
+ if (node == -1)
+ page = alloc_pages(flags, s->order);
+ else
+ page = alloc_pages_node(node, flags, s->order);
+
+ if (!page)
+ return NULL;
+
+ mod_zone_page_state(page_zone(page),
+ (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+ NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
+ pages);
+
+ if (unlikely(s->ctor)) {
+ void *start = page_address(page);
+ void *end = start + (pages << PAGE_SHIFT);
+ void *p;
+ int mode = 1;
+
+ if (!(flags & __GFP_WAIT))
+ mode |= SLAB_CTOR_ATOMIC;
+
+ for (p = start; p <= end - s->size; p += s->size)
+ s->ctor(p, s, mode);
+ }
+ return page;
+}
+
+static struct page *new_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ struct page *page;
+ struct kmem_cache_node *n;
+
+ BUG_ON(flags & ~(GFP_DMA | GFP_LEVEL_MASK | __GFP_NO_GROW));
+ if (flags & __GFP_NO_GROW)
+ return NULL;
+
+ if (flags & __GFP_WAIT)
+ local_irq_enable();
+
+ page = allocate_slab(s, flags & GFP_LEVEL_MASK, node);
+ if (!page)
+ goto out;
+
+ n = get_node(s, page_to_nid(page));
+ if (n)
+ atomic_long_inc(&n->nr_slabs);
+ page->offset = s->offset / sizeof(void *);
+ page->slab = s;
+ page->flags |= 1 << PG_slab;
+ if (s->flags & (SLAB_DEBUG_FREE | SLAB_RED_ZONE | SLAB_POISON |
+ SLAB_STORE_USER | SLAB_TRACE) ||
+ s->objects == 1)
+ page->flags |= 1 << PG_error;
+
+ if (s->objects > 1) {
+ void *start = page_address(page);
+ void *end = start + s->objects * s->size;
+ void *last = start;
+ void *p = start + s->size;
+
+ if (unlikely(s->flags & SLAB_POISON))
+ memset(start, POISON_INUSE, PAGE_SIZE << s->order);
+ while (p < end) {
+ if (PageError(page)) {
+ init_object(s, last, 0);
+ init_tracking(s, last);
+ }
+ set_freepointer(s, last, p);
+ last = p;
+ p += s->size;
+ }
+ set_freepointer(s, last, NULL);
+ page->freelist = start;
+ page->inuse = 0;
+ if (PageError(page)) {
+ init_object(s, last, 0);
+ init_tracking(s, last);
+ }
+ }
+
+out:
+ if (flags & __GFP_WAIT)
+ local_irq_disable();
+ return page;
+}
+
+
+static void __free_slab(struct kmem_cache *s, struct page *page)
+{
+ int pages = 1 << s->order;
+
+ if (unlikely(PageError(page) || s->dtor)) {
+ void *start = page_address(page);
+ void *end = start + (pages << PAGE_SHIFT);
+ void *p;
+ int n;
+
+ for (p = start; p <= end - s->size; p += s->size) {
+ if (s->dtor)
+ s->dtor(p, s, 0);
+ else
+ check_object(s, page, p, 0);
+ }
+ n = end - p;
+ if (n && (s->flags & SLAB_POISON) &&
+ check_bytes(p, POISON_INUSE, n)) {
+ printk(KERN_ERR "SLUB: %s slab %p: Slab"
+ "Padding fails check\n", s->name, p);
+ print_section("Slab Pad", p, n);
+ }
+ }
+
+ mod_zone_page_state(page_zone(page),
+ (s->flags & SLAB_RECLAIM_ACCOUNT) ?
+ NR_SLAB_RECLAIMABLE : NR_SLAB_UNRECLAIMABLE,
+ - pages);
+
+ __free_pages(page, s->order);
+}
+
+static void rcu_free_slab(struct rcu_head *h)
+{
+ struct page *page;
+ struct kmem_cache *s;
+
+ page = container_of((struct list_head *)h, struct page, lru);
+ s = (struct kmem_cache *)page->mapping;
+ page->mapping = NULL;
+ __free_slab(s, page);
+}
+
+static void free_slab(struct kmem_cache *s, struct page *page)
+{
+ if (unlikely(s->flags & SLAB_DESTROY_BY_RCU)) {
+ /*
+ * RCU free overloads the RCU head over the LRU
+ */
+ struct rcu_head *head = (void *)&page->lru;
+
+ page->mapping = (void *)s;
+ call_rcu(head, rcu_free_slab);
+ } else
+ __free_slab(s, page);
+}
+
+static void discard_slab(struct kmem_cache *s, struct page *page)
+{
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ atomic_long_dec(&n->nr_slabs);
+
+ page->mapping = NULL;
+ reset_page_mapcount(page);
+ page->flags &= ~(1 << PG_slab | 1 << PG_error);
+ free_slab(s, page);
+}
+
+/*
+ * Per slab locking using the pagelock
+ */
+static __always_inline void slab_lock(struct page *page)
+{
+#ifdef CONFIG_SMP
+ bit_spin_lock(PG_locked, &page->flags);
+#endif
+}
+
+static __always_inline void slab_unlock(struct page *page)
+{
+#ifdef CONFIG_SMP
+ bit_spin_unlock(PG_locked, &page->flags);
+#endif
+}
+
+static __always_inline int slab_trylock(struct page *page)
+{
+ int rc = 1;
+#ifdef CONFIG_SMP
+ rc = bit_spin_trylock(PG_locked, &page->flags);
+#endif
+ return rc;
+}
+
+/*
+ * Management of partially allocated slabs
+ */
+static void __always_inline add_partial(struct kmem_cache *s, struct page *page)
+{
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ spin_lock(&n->list_lock);
+ n->nr_partial++;
+ list_add_tail(&page->lru, &n->partial);
+ spin_unlock(&n->list_lock);
+}
+
+static void __always_inline remove_partial(struct kmem_cache *s,
+ struct page *page)
+{
+ struct kmem_cache_node *n = get_node(s, page_to_nid(page));
+
+ spin_lock(&n->list_lock);
+ list_del(&page->lru);
+ n->nr_partial--;
+ spin_unlock(&n->list_lock);
+}
+
+/*
+ * Lock page and remove it from the partial list
+ *
+ * Must hold list_lock
+ */
+static __always_inline int lock_and_del_slab(struct kmem_cache_node *n,
+ struct page *page)
+{
+ if (slab_trylock(page)) {
+ list_del(&page->lru);
+ n->nr_partial--;
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Try to get a partial slab from a specific node
+ */
+static struct page *get_partial_node(struct kmem_cache_node *n)
+{
+ struct page *page;
+
+ /*
+ * Racy check. If we mistakenly see no partial slabs then we
+ * just allocate an empty slab. If we mistakenly try to get a
+ * partial slab then get_partials() will return NULL.
+ */
+ if (!n || !n->nr_partial)
+ return NULL;
+
+ spin_lock(&n->list_lock);
+ list_for_each_entry(page, &n->partial, lru)
+ if (lock_and_del_slab(n, page))
+ goto out;
+ page = NULL;
+out:
+ spin_unlock(&n->list_lock);
+ return page;
+}
+
+/*
+ * Get a page from somewhere. Search in increasing NUMA
+ * distances.
+ */
+static struct page *get_any_partial(struct kmem_cache *s, gfp_t flags)
+{
+#ifdef CONFIG_NUMA
+ struct zonelist *zonelist = &NODE_DATA(slab_node(current->mempolicy))
+ ->node_zonelists[gfp_zone(flags)];
+ struct zone **z;
+ struct page *page;
+
+ for (z = zonelist->zones; *z; z++) {
+ struct kmem_cache_node *n;
+
+ n = get_node(s, zone_to_nid(*z));
+
+ if (n && cpuset_zone_allowed_hardwall(*z, flags) &&
+ n->nr_partial > 2) {
+ page = get_partial_node(n);
+ if (page)
+ return page;
+ }
+ }
+#endif
+ return NULL;
+}
+
+/*
+ * Get a partial page, lock it and return it.
+ */
+static struct page *get_partial(struct kmem_cache *s, gfp_t flags, int node)
+{
+ struct page *page;
+ int searchnode = (node == -1) ? numa_node_id() : node;
+
+ page = get_partial_node(get_node(s, searchnode));
+ if (page || (flags & __GFP_THISNODE))
+ return page;
+
+ return get_any_partial(s, flags);
+}
+
+/*
+ * Move a page back to the lists.
+ *
+ * Must be called with the slab lock held.
+ *
+ * On exit the slab lock will have been dropped.
+ */
+static void __always_inline putback_slab(struct kmem_cache *s, struct page *page)
+{
+ if (page->inuse) {
+ if (page->inuse < s->objects)
+ add_partial(s, page);
+ slab_unlock(page);
+ } else {
+ slab_unlock(page);
+ discard_slab(s, page);
+ }
+}
+
+/*
+ * Remove the cpu slab
+ */
+static void __always_inline deactivate_slab(struct kmem_cache *s,
+ struct page *page, int cpu)
+{
+ s->cpu_slab[cpu] = NULL;
+ ClearPageActive(page);
+ ClearPageReferenced(page);
+
+ putback_slab(s, page);
+}
+
+static void flush_slab(struct kmem_cache *s, struct page *page, int cpu)
+{
+ slab_lock(page);
+ deactivate_slab(s, page, cpu);
+}
+
+/*
+ * Flush cpu slab.
+ * Called from IPI handler with interrupts disabled.
+ */
+static void __flush_cpu_slab(struct kmem_cache *s, int cpu)
+{
+ struct page *page = s->cpu_slab[cpu];
+
+ if (likely(page))
+ flush_slab(s, page, cpu);
+}
+
+static void flush_cpu_slab(void *d)
+{
+ struct kmem_cache *s = d;
+ int cpu = smp_processor_id();
+
+ __flush_cpu_slab(s, cpu);
+}
+
+#ifdef CONFIG_SMP
+/*
+ * Called from IPI to check and flush cpu slabs.
+ */
+static void check_flush_cpu_slab(void *private)
+{
+ struct kmem_cache *s = private;
+ int cpu = smp_processor_id();
+ struct page *page = s->cpu_slab[cpu];
+
+ if (page) {
+ if (!TestClearPageReferenced(page))
+ return;
+ flush_slab(s, page, cpu);
+ }
+ atomic_dec(&s->cpu_slabs);
+}
+
+/*
+ * Called from eventd
+ */
+static void flusher(struct work_struct *w)
+{
+ struct kmem_cache *s = container_of(w, struct kmem_cache, flush.work);
+
+ if (!mutex_trylock(&s->flushing))
+ return;
+
+ atomic_set(&s->cpu_slabs, num_online_cpus());
+ on_each_cpu(check_flush_cpu_slab, s, 1, 1);
+ if (atomic_read(&s->cpu_slabs))
+ schedule_delayed_work(&s->flush, 30 * HZ);
+ mutex_unlock(&s->flushing);
+}
+
+static void flush_all(struct kmem_cache *s)
+{
+ if (atomic_read(&s->cpu_slabs)) {
+ mutex_lock(&s->flushing);
+ cancel_delayed_work(&s->flush);
+ atomic_set(&s->cpu_slabs, 0);
+ on_each_cpu(flush_cpu_slab, s, 1, 1);
+ mutex_unlock(&s->flushing);
+ }
+}
+#else
+static void flush_all(struct kmem_cache *s)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ flush_cpu_slab(s);
+ local_irq_restore(flags);
+}
+#endif
+
+static __always_inline void *slab_alloc(struct kmem_cache *s,
+ gfp_t gfpflags, int node)
+{
+ struct page *page;
+ void **object;
+ unsigned long flags;
+ int cpu;
+
+ local_irq_save(flags);
+ cpu = smp_processor_id();
+ page = s->cpu_slab[cpu];
+ if (!page)
+ goto new_slab;
+
+ slab_lock(page);
+ if (unlikely(node != -1 && page_to_nid(page) != node))
+ goto another_slab;
+redo:
+ if (unlikely(!page->freelist))
+ goto another_slab;
+ object = page->freelist;
+ if (unlikely(PageError(page))) {
+ if (!alloc_object_checks(s, page, object))
+ goto another_slab;
+ if (s->flags & SLAB_STORE_USER)
+ set_tracking(s, object, 0);
+ }
+ page->inuse++;
+ page->freelist = object[page->offset];
+ SetPageReferenced(page);
+ slab_unlock(page);
+ local_irq_restore(flags);
+ return object;
+
+another_slab:
+ deactivate_slab(s, page, cpu);
+
+new_slab:
+ page = get_partial(s, gfpflags, node);
+ if (unlikely(!page)) {
+
+ page = new_slab(s, gfpflags, node);
+ if (!page) {
+ local_irq_restore(flags);
+ return NULL;
+ }
+
+ if (s->objects == 1) {
+ local_irq_restore(flags);
+ return page_address(page);
+ }
+
+ if (s->cpu_slab[cpu]) {
+ /*
+ * Someone else populated the cpu_slab while
+ * we enabled interrupts. The page may not
+ * be on the required node.
+ */
+ if (node == -1 ||
+ page_to_nid(s->cpu_slab[cpu]) == node) {
+ /*
+ * Current cpuslab is acceptable and we
+ * want the current one since its cache hot
+ */
+ discard_slab(s, page);
+ page = s->cpu_slab[cpu];
+ slab_lock(page);
+ goto redo;
+ }
+ flush_slab(s, s->cpu_slab[cpu], cpu);
+ }
+ slab_lock(page);
+ }
+
+ s->cpu_slab[cpu] = page;
+ SetPageActive(page);
+
+#ifdef CONFIG_SMP
+ if (!atomic_read(&s->cpu_slabs) && keventd_up()) {
+ atomic_inc(&s->cpu_slabs);
+ schedule_delayed_work(&s->flush, 30 * HZ);
+ }
+#endif
+ goto redo;
+}
+
+void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
+{
+ return slab_alloc(s, gfpflags, -1);
+}
+EXPORT_SYMBOL(kmem_cache_alloc);
+
+#ifdef CONFIG_NUMA
+void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
+{
+ return slab_alloc(s, gfpflags, node);
+}
+EXPORT_SYMBOL(kmem_cache_alloc_node);
+#endif
+
+void kmem_cache_free(struct kmem_cache *s, void *x)
+{
+ struct page * page;
+ void *prior;
+ void **object = (void *)x;
+ unsigned long flags;
+
+ if (!object)
+ return;
+
+ page = virt_to_page(x);
+
+ if (unlikely(PageCompound(page)))
+ page = page->first_page;
+
+ if (!s)
+ s = page->slab;
+
+ local_irq_save(flags);
+
+ if (unlikely(PageError(page)) && s->objects == 1)
+ goto single_object_slab;
+
+ slab_lock(page);
+
+ if (unlikely(PageError(page))) {
+ if (!free_object_checks(s, page, x))
+ goto out_unlock;
+ if (s->flags & SLAB_STORE_USER)
+ set_tracking(s, object, 1);
+ }
+
+ prior = object[page->offset] = page->freelist;
+ page->freelist = object;
+ page->inuse--;
+
+ if (likely(PageActive(page) || (page->inuse && prior)))
+ goto out_unlock;
+
+ if (!prior) {
+ /*
+ * The slab was full before. It will have one free
+ * object now. So move to the partial list.
+ */
+ add_partial(s, page);
+ goto out_unlock;
+ }
+
+ /*
+ * All object have been freed.
+ */
+ remove_partial(s, page);
+ slab_unlock(page);
+single_object_slab:
+ discard_slab(s, page);
+ local_irq_restore(flags);
+ return;
+
+out_unlock:
+ slab_unlock(page);
+ local_irq_restore(flags);
+}
+EXPORT_SYMBOL(kmem_cache_free);
+
+/* Figure out on which slab object the object resides */
+static __always_inline struct page *get_object_page(const void *x)
+{
+ struct page *page = virt_to_page(x);
+
+ if (unlikely(PageCompound(page)))
+ page = page->first_page;
+
+ if (!PageSlab(page))
+ return NULL;
+
+ return page;
+}
+
+/*
+ * kmem_cache_open produces objects aligned at "size" and the first object
+ * is placed at offset 0 in the slab (We have no metainformation on the
+ * slab, all slabs are in essence "off slab").
+ *
+ * In order to get the desired alignment one just needs to align the
+ * size.
+ *
+ * Notice that the allocation order determines the sizes of the per cpu
+ * caches. Each processor has always one slab available for allocations.
+ * Increasing the allocation order reduces the number of times that slabs
+ * must be moved on and off the partial lists and therefore may influence
+ * locking overhead.
+ *
+ * The offset is used to relocate the free list link in each object. It is
+ * therefore possible to move the free list link behind the object. This
+ * is necessary for RCU to work properly and also useful for debugging.
+ *
+ * No freelists are necessary if there is only one element per slab.
+ */
+
+/*
+ * Mininum order of slab pages. This influences locking overhead and slab
+ * fragmentation. A higher order reduces the number of partial slabs
+ * and increases the number of allocations possible without having to
+ * take the list_lock.
+ */
+static int slub_min_order = 0;
+
+/*
+ * Merge control. If this is set then no merging of slab caches will occur.
+ */
+static int slub_nomerge = 0;
+
+/*
+ * Debug settings:
+ */
+static int slub_debug = 0;
+
+static char *slub_debug_slabs = NULL;
+
+static int calculate_order(int size)
+{
+ int order;
+ int rem;
+
+ if ((size & (size -1)) == 0) {
+ /*
+ * We can use the page allocator if the requested size
+ * is compatible with the page sizes supported.
+ */
+ int order = fls(size) - 1 - PAGE_SHIFT;
+
+ if (order >= 0)
+ return order;
+ }
+
+ for (order = max(slub_min_order, fls(size - 1) - PAGE_SHIFT);
+ order < MAX_ORDER; order++) {
+ unsigned long slab_size = PAGE_SIZE << order;
+
+ if (slab_size < size)
+ continue;
+
+ rem = slab_size % size;
+
+ if (rem * 8 <= PAGE_SIZE << order)
+ break;
+
+ }
+ if (order >= MAX_ORDER)
+ return -E2BIG;
+ return order;
+}
+
+static unsigned long calculate_alignment(unsigned long flags,
+ unsigned long align)
+{
+ if (flags & SLAB_HWCACHE_ALIGN)
+ return L1_CACHE_BYTES;
+ if (flags & SLAB_MUST_HWCACHE_ALIGN)
+ return max(align, (unsigned long)L1_CACHE_BYTES);
+
+ if (align < ARCH_SLAB_MINALIGN)
+ return ARCH_SLAB_MINALIGN;
+
+ return ALIGN(align, sizeof(void *));
+}
+
+static void free_kmem_cache_nodes(struct kmem_cache *s)
+{
+#ifdef CONFIG_NUMA
+ int node;
+
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = s->node[node];
+ if (n && n != &s->local_node)
+ kfree(n);
+ s->node[node] = NULL;
+ }
+#endif
+}
+
+static void init_kmem_cache_node(struct kmem_cache_node *n)
+{
+ memset(n, 0, sizeof(struct kmem_cache_node));
+ atomic_long_set(&n->nr_slabs, 0);
+ spin_lock_init(&n->list_lock);
+ INIT_LIST_HEAD(&n->partial);
+}
+
+static int init_kmem_cache_nodes(struct kmem_cache *s, gfp_t gfpflags)
+{
+#ifdef CONFIG_NUMA
+ int node;
+ int local_node;
+
+ if (slab_state == UP)
+ local_node = page_to_nid(virt_to_page(s));
+ else
+ local_node = 0;
+
+ for_each_online_node(node) {
+ struct kmem_cache_node *n;
+
+ if (local_node == node)
+ n = &s->local_node;
+ else
+ if (slab_state == DOWN) {
+ /*
+ * No kmalloc_node yet so do it by hand.
+ * We know that this is the first slab on the
+ * node for this slabcache. There are no concurrent
+ * accesses possible. Which simplifies things.
+ */
+ unsigned long flags;
+ struct page *page;
+
+ BUG_ON(s->size < sizeof(struct kmem_cache_node));
+ local_irq_save(flags);
+ page = new_slab(s, gfpflags, node);
+
+ BUG_ON(!page);
+ n = page->freelist;
+ page->freelist = *(void **)page->freelist;
+ page->inuse++;
+ local_irq_restore(flags);
+ } else
+ n = kmalloc_node(sizeof(struct kmem_cache_node),
+ gfpflags, node);
+
+ if (!n) {
+ free_kmem_cache_nodes(s);
+ return 0;
+ }
+
+ s->node[node] = n;
+ init_kmem_cache_node(n);
+
+ if (slab_state == DOWN)
+ atomic_long_inc(&n->nr_slabs);
+ }
+#else
+ init_kmem_cache_node(&s->local_node);
+#endif
+ return 1;
+}
+
+static int kmem_cache_open(struct kmem_cache *s, gfp_t gfpflags,
+ const char *name, size_t size,
+ size_t align, unsigned long flags,
+ void (*ctor)(void *, struct kmem_cache *, unsigned long),
+ void (*dtor)(void *, struct kmem_cache *, unsigned long))
+{
+ int tentative_size;
+ BUG_ON(flags & SLUB_UNIMPLEMENTED);
+
+ memset(s, 0, kmem_size);
+
+ /*
+ * Enable debugging if selected on the kernel commandline.
+ */
+ if (slub_debug &&
+ (!slub_debug_slabs ||
+ strncmp(slub_debug_slabs, name, strlen(slub_debug_slabs)) == 0))
+ flags |= slub_debug;
+
+ if ((flags & SLAB_POISON) &&((flags & SLAB_DESTROY_BY_RCU) ||
+ ctor || dtor)) {
+ if (!(slub_debug & SLAB_POISON))
+ printk(KERN_WARNING "SLUB %s: Clearing SLAB_POISON "
+ "because de/constructor exists.\n",
+ s->name);
+ flags &= ~SLAB_POISON;
+ }
+
+ tentative_size = ALIGN(size, calculate_alignment(align, flags));
+
+ /*
+ * Single object slabs are passed through to the page allocator
+ * and therefore the checks we can do are limited.
+ */
+ if (size * 2 > (PAGE_SIZE << calculate_order(tentative_size)))
+ flags &= ~(SLAB_RED_ZONE | SLAB_DEBUG_FREE | \
+ SLAB_STORE_USER | SLAB_POISON);
+
+ s->name = name;
+ s->ctor = ctor;
+ s->dtor = dtor;
+ s->objsize = size;
+ s->flags = flags;
+
+ size = ALIGN(size, sizeof(void *));
+
+ /*
+ * If we redzone then check if we have space through above
+ * alignment. If not then add an additional word, so
+ * that we have a guard value to check for overwrites.
+ */
+ if ((s->flags & SLAB_RED_ZONE) && size == s->objsize)
+ size += sizeof(void *);
+
+ s->inuse = size;
+
+ if (size * 2 < (PAGE_SIZE << calculate_order(size)) &&
+ ((flags & (SLAB_DESTROY_BY_RCU | SLAB_POISON)) ||
+ ctor || dtor)) {
+ /*
+ * Relocate free pointer after the object if it is not
+ * permitted to overwrite the first word of the object on
+ * kmem_cache_free.
+ *
+ * This is the case if we do RCU, have a constructor or
+ * destructor or are poisoning the objects.
+ */
+ s->offset = size;
+ size += sizeof(void *);
+ }
+
+ if (flags & SLAB_STORE_USER)
+ size += 2 * sizeof(void *);
+
+ align = calculate_alignment(flags, align);
+
+ size = ALIGN(size, align);
+ s->size = size;
+
+ s->order = calculate_order(size);
+ if (s->order < 0)
+ goto error;
+
+ s->objects = (PAGE_SIZE << s->order) / size;
+ if (!s->objects || s->objects > 65535)
+ goto error;
+
+ s->refcount = 1;
+
+#ifdef CONFIG_SMP
+ mutex_init(&s->flushing);
+ atomic_set(&s->cpu_slabs, 0);
+ INIT_DELAYED_WORK(&s->flush, flusher);
+#endif
+ if (init_kmem_cache_nodes(s, gfpflags & ~SLUB_DMA)) {
+ return 1;
+ }
+error:
+ if (flags & SLAB_PANIC)
+ panic("Cannot create slab %s size=%lu realsize=%u "
+ "order=%u offset=%u flags=%lx\n",
+ s->name, (unsigned long)size, s->size, s->order,
+ s->offset, flags);
+ return 0;
+}
+EXPORT_SYMBOL(kmem_cache_open);
+
+/*
+ * Check if a given pointer is valid
+ */
+int kmem_ptr_validate(struct kmem_cache *s, const void *object)
+{
+ struct page * page;
+ void *addr;
+
+ page = get_object_page(object);
+
+ if (!page || s != page->slab)
+ /* No slab or wrong slab */
+ return 0;
+
+ addr = page_address(page);
+ if (object < addr || object >= addr + s->objects * s->size)
+ /* Out of bounds */
+ return 0;
+
+ if ((object - addr) & s->size)
+ /* Improperly aligned */
+ return 0;
+
+ /*
+ * We could also check here if the object is on the slabs freelist.
+ * But this would be too expensive and it seems that the main
+ * purpose of kmem_ptr_valid is to check if the object belongs
+ * to a certain slab.
+ */
+ return 1;
+}
+EXPORT_SYMBOL(kmem_ptr_validate);
+
+/*
+ * Determine the size of a slab object
+ */
+unsigned int kmem_cache_size(struct kmem_cache *s)
+{
+ return s->objsize;
+}
+EXPORT_SYMBOL(kmem_cache_size);
+
+const char *kmem_cache_name(struct kmem_cache *s)
+{
+ return s->name;
+}
+EXPORT_SYMBOL(kmem_cache_name);
+
+static int free_list(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct list_head *list)
+{
+ int slabs_inuse = 0;
+ unsigned long flags;
+ struct page *page, *h;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry_safe(page, h, list, lru)
+ if (!page->inuse) {
+ list_del(&page->lru);
+ discard_slab(s, page);
+ } else
+ slabs_inuse++;
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ return slabs_inuse;
+}
+
+/*
+ * Release all resources used by slab cache
+ * (if possible...)
+ */
+static int kmem_cache_close(struct kmem_cache *s)
+{
+ int node;
+
+ flush_all(s);
+
+ /* Attempt to free all objects */
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = get_node(s, node);
+
+ free_list(s, n, &n->partial);
+ if (atomic_long_read(&n->nr_slabs))
+ return 1;
+ }
+ free_kmem_cache_nodes(s);
+ return 0;
+}
+EXPORT_SYMBOL(kmem_cache_close);
+
+/*
+ * Close a cache and release the kmem_cache structure
+ * (must be used for caches created using kmem_cache_create)
+ */
+void kmem_cache_destroy(struct kmem_cache *s)
+{
+ down_write(&slub_lock);
+ if (s->refcount)
+ s->refcount--;
+ else {
+ list_del(&s->list);
+ BUG_ON(kmem_cache_close(s));
+ kfree(s);
+ }
+ up_write(&slub_lock);
+}
+EXPORT_SYMBOL(kmem_cache_destroy);
+
+static unsigned long slab_objects(struct kmem_cache *s,
+ unsigned long *p_total, unsigned long *p_cpu_slabs,
+ unsigned long *p_partial, unsigned long *nodes)
+{
+ int nr_slabs = 0;
+ int nr_partial_slabs = 0;
+ int nr_cpu_slabs = 0;
+ int in_cpu_slabs = 0;
+ int in_partial_slabs = 0;
+ int cpu;
+ int node;
+ unsigned long flags;
+ struct page *page;
+
+ for_each_online_node(node) {
+ struct kmem_cache_node *n = get_node(s, node);
+
+ nr_slabs += atomic_read(&n->nr_slabs);
+ nr_partial_slabs += n->nr_partial;
+
+ nodes[node] = atomic_read(&n->nr_slabs) +
+ n->nr_partial;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry(page, &n->partial, lru)
+ in_partial_slabs += page->inuse;
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ }
+
+ for_each_possible_cpu(cpu) {
+ page = s->cpu_slab[cpu];
+ if (page) {
+ nr_cpu_slabs++;
+ in_cpu_slabs += page->inuse;
+ nodes[page_to_nid(page)]++;
+ }
+ }
+
+ if (p_partial)
+ *p_partial = nr_partial_slabs;
+
+ if (p_cpu_slabs)
+ *p_cpu_slabs = nr_cpu_slabs;
+
+ if (p_total)
+ *p_total = nr_slabs;
+
+ return in_partial_slabs + in_cpu_slabs +
+ (nr_slabs - nr_partial_slabs - nr_cpu_slabs) * s->objects;
+}
+
+/********************************************************************
+ * Kmalloc subsystem
+ *******************************************************************/
+
+struct kmem_cache kmalloc_caches[KMALLOC_NR_CACHES] __cacheline_aligned;
+EXPORT_SYMBOL(kmalloc_caches);
+
+#ifdef CONFIG_ZONE_DMA
+static struct kmem_cache *kmalloc_caches_dma[KMALLOC_NR_CACHES];
+#endif
+
+static int __init setup_slub_min_order(char *str)
+{
+ get_option (&str, &slub_min_order);
+
+ return 1;
+}
+
+__setup("slub_min_order=", setup_slub_min_order);
+
+static int __init setup_slub_nomerge(char *str)
+{
+ slub_nomerge = 1;
+ return 1;
+}
+
+__setup("slub_nomerge", setup_slub_nomerge);
+
+static int __init setup_slub_debug(char *str)
+{
+ if (!str || *str != '=')
+ slub_debug = DEBUG_DEFAULT_FLAGS;
+ else {
+ str++;
+ if (*str == 0 || *str == ',')
+ slub_debug = DEBUG_DEFAULT_FLAGS;
+ else
+ for( ;*str && *str != ','; str++)
+ switch (*str) {
+ case 'f' : case 'F' : slub_debug |= SLAB_DEBUG_FREE;break;
+ case 'z' : case 'Z' : slub_debug |= SLAB_RED_ZONE;break;
+ case 'p' : case 'P' : slub_debug |= SLAB_POISON;break;
+ case 'u' : case 'U' : slub_debug |= SLAB_STORE_USER;break;
+ case 't' : case 'T' : slub_debug |= SLAB_TRACE;break;
+ default:
+ printk(KERN_CRIT "slub_debug option '%c' unknown. skipped\n",*str);
+ }
+ }
+
+ if (*str == ',')
+ slub_debug_slabs = str + 1;
+ return 1;
+}
+
+__setup("slub_debug", setup_slub_debug);
+
+static struct kmem_cache *create_kmalloc_cache(struct kmem_cache *s,
+ const char *name, int size, gfp_t gfp_flags)
+{
+ unsigned int flags = 0;
+
+ if (gfp_flags & SLUB_DMA)
+ flags = SLAB_CACHE_DMA;
+
+ down_write(&slub_lock);
+ if (!kmem_cache_open(s, gfp_flags, name, size, ARCH_KMALLOC_MINALIGN,
+ flags, NULL, NULL))
+ panic("Creation of kmalloc slab %s size=%d failed.\n",
+ name, size);
+ list_add(&s->list, &slab_caches);
+ up_write(&slub_lock);
+ return s;
+}
+
+static struct kmem_cache *get_slab(size_t size, gfp_t flags)
+{
+ int index = kmalloc_index(size) - KMALLOC_SHIFT_LOW;
+
+ /* SLAB allows allocations with zero size. So warn on those */
+ WARN_ON(size == 0);
+ /* Allocation too large? */
+ BUG_ON(index < 0);
+
+#ifdef CONFIG_ZONE_DMA
+ if ((flags & SLUB_DMA)) {
+ struct kmem_cache *s;
+ struct kmem_cache *x;
+ char *text;
+ size_t realsize;
+
+ s = kmalloc_caches_dma[index];
+ if (s)
+ return s;
+
+ /* Dynamically create dma cache */
+ x = kmalloc(kmem_size, flags & ~SLUB_DMA);
+ if (!x)
+ panic("Unable to allocate memory for dma cache\n");
+
+#ifdef KMALLOC_EXTRA
+ if (index <= KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW)
+#endif
+ realsize = 1 << (index + KMALLOC_SHIFT_LOW);
+#ifdef KMALLOC_EXTRA
+ else {
+ index -= KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW +1;
+ if (!index)
+ realsize = 96;
+ else
+ realsize = 192;
+ }
+#endif
+
+ text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
+ (unsigned int)realsize);
+ s = create_kmalloc_cache(x, text, realsize, flags);
+ kmalloc_caches_dma[index] = s;
+ return s;
+ }
+#endif
+ return &kmalloc_caches[index];
+}
+
+void *__kmalloc(size_t size, gfp_t flags)
+{
+ return kmem_cache_alloc(get_slab(size, flags), flags);
+}
+EXPORT_SYMBOL(__kmalloc);
+
+#ifdef CONFIG_NUMA
+void *__kmalloc_node(size_t size, gfp_t flags, int node)
+{
+ return kmem_cache_alloc_node(get_slab(size, flags),
+ flags, node);
+}
+EXPORT_SYMBOL(__kmalloc_node);
+#endif
+
+size_t ksize(const void *object)
+{
+ struct page *page = get_object_page(object);
+ struct kmem_cache *s;
+
+ BUG_ON(!page);
+ s = page->slab;
+ BUG_ON(!s);
+ if (s->flags & SLAB_RED_ZONE)
+ return s->objsize;
+ if (s->flags & (SLAB_DESTROY_BY_RCU | SLAB_STORE_USER))
+ return s->inuse;
+ return s->size;
+}
+EXPORT_SYMBOL(ksize);
+
+void kfree(const void *object)
+{
+ kmem_cache_free(NULL, (void *)object);
+}
+EXPORT_SYMBOL(kfree);
+
+/**
+ * krealloc - reallocate memory. The contents will remain unchanged.
+ *
+ * @p: object to reallocate memory for.
+ * @new_size: how many bytes of memory are required.
+ * @flags: the type of memory to allocate.
+ *
+ * The contents of the object pointed to are preserved up to the
+ * lesser of the new and old sizes. If @p is %NULL, krealloc()
+ * behaves exactly like kmalloc(). If @size is 0 and @p is not a
+ * %NULL pointer, the object pointed to is freed.
+ */
+void *krealloc(const void *p, size_t new_size, gfp_t flags)
+{
+ struct kmem_cache *new_cache;
+ void *ret;
+ struct page *page;
+
+ if (unlikely(!p))
+ return kmalloc(new_size, flags);
+
+ if (unlikely(!new_size)) {
+ kfree(p);
+ return NULL;
+ }
+
+ page = virt_to_page(p);
+
+ if (unlikely(PageCompound(page)))
+ page = page->first_page;
+
+ new_cache = get_slab(new_size, flags);
+
+ /*
+ * If new size fits in the current cache, bail out.
+ */
+ if (likely(page->slab == new_cache))
+ return (void *)p;
+
+ /*
+ * We are on the slow-path here so do not use __cache_alloc
+ * because it bloats kernel text.
+ */
+ ret = kmalloc(new_size, flags);
+ if (ret) {
+ memcpy(ret, p, min(new_size, ksize(p)));
+ kfree(p);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(krealloc);
+
+/********************************************************************
+ * Basic setup of slabs
+ *******************************************************************/
+
+void __init kmem_cache_init(void)
+{
+ int i;
+ int kmem_cache_node_cache =
+ kmalloc_index(sizeof(struct kmem_cache_node));
+
+ BUG_ON(kmem_cache_node_cache < 0 ||
+ kmem_cache_node_cache > KMALLOC_SHIFT_HIGH);
+
+ /*
+ * Must first have the slab cache available for the allocations of the
+ * struct kmalloc_cache_node's. There is special bootstrap code in
+ * kmem_cache_open for the situation when slab_state == DOWN.
+ */
+ create_kmalloc_cache(&kmalloc_caches[kmem_cache_node_cache
+ - KMALLOC_SHIFT_LOW],
+ "kmalloc",
+ 1 << kmem_cache_node_cache,
+ GFP_KERNEL);
+
+ /* Now we are able to allocate the per node structures */
+ slab_state = PARTIAL;
+
+ for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
+ if (i == kmem_cache_node_cache)
+ continue;
+
+ create_kmalloc_cache(
+ &kmalloc_caches[i - KMALLOC_SHIFT_LOW],
+ "kmalloc", 1 << i, GFP_KERNEL);
+ }
+
+#ifdef KMALLOC_EXTRA
+ /* Caches that are not of the two-to-the-power-of size */
+ create_kmalloc_cache(&kmalloc_caches
+ [KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW + 1],
+ "kmalloc-96", 96, GFP_KERNEL);
+ create_kmalloc_cache(&kmalloc_caches
+ [KMALLOC_SHIFT_HIGH - KMALLOC_SHIFT_LOW + 2],
+ "kmalloc-192", 192, GFP_KERNEL);
+#endif
+ slab_state = UP;
+
+ /* Provide the correct kmalloc names now that the caches are up */
+ for (i = KMALLOC_SHIFT_LOW; i <= KMALLOC_SHIFT_HIGH; i++) {
+ char *name = kasprintf(GFP_KERNEL, "kmalloc-%d", 1 << i);
+
+ BUG_ON(!name);
+ kmalloc_caches[i - KMALLOC_SHIFT_LOW].name = name;
+ };
+
+#ifdef CONFIG_SMP
+ register_cpu_notifier(&slab_notifier);
+#endif
+ if (nr_cpu_ids) /* Remove when nr_cpu_ids was fixed ! */
+ kmem_size = offsetof(struct kmem_cache, cpu_slab)
+ + nr_cpu_ids * sizeof(struct page *);
+
+ printk(KERN_INFO "SLUB V4: General Slabs=%d, HW alignment=%d, Processors=%d, Nodes=%d\n",
+ KMALLOC_SHIFT_HIGH + KMALLOC_EXTRAS + 1 - KMALLOC_SHIFT_LOW,
+ L1_CACHE_BYTES, nr_cpu_ids, nr_node_ids);
+}
+
+static struct kmem_cache *kmem_cache_dup(struct kmem_cache *s,
+ gfp_t flags, const char *name)
+{
+ if (s->refcount == 1) {
+ s->refcount++;
+ if (!s->aliases)
+ s->aliases = kstrdup(name, flags);
+ else {
+ char *x = s->aliases;
+ s->aliases = kasprintf(flags, "%s/%s", s->aliases, name);
+ kfree(x);
+ }
+ } else
+ s = NULL;
+ return s;
+}
+
+/*
+ * Find a mergeable slab cache
+ */
+static struct kmem_cache *find_mergeable(size_t size,
+ size_t align, unsigned long flags,
+ void (*ctor)(void *, struct kmem_cache *, unsigned long),
+ void (*dtor)(void *, struct kmem_cache *, unsigned long))
+{
+ struct list_head *h;
+
+ if (slub_nomerge || (flags & SLUB_NEVER_MERGE))
+ return NULL;
+
+ if (ctor || dtor)
+ return NULL;
+
+ size = ALIGN(size, sizeof(void *));
+ align = calculate_alignment(flags, align);
+ size = ALIGN(size, align);
+
+ list_for_each(h, &slab_caches) {
+ struct kmem_cache *s =
+ container_of(h, struct kmem_cache, list);
+
+ if (size > s->size)
+ continue;
+
+ if (s->flags & SLUB_NEVER_MERGE)
+ continue;
+
+ if (s->dtor || s->ctor)
+ continue;
+
+ if (((flags | slub_debug) & SLUB_MERGE_SAME) !=
+ (s->flags & SLUB_MERGE_SAME))
+ continue;
+ /*
+ * Check if alignment is compatible.
+ * Courtesy of Adrian Drzewiecki
+ */
+ if ((s->size & ~(align -1)) != s->size)
+ continue;
+
+ if (s->size - size >= sizeof(void *))
+ continue;
+
+ return s;
+ }
+ return NULL;
+}
+
+struct kmem_cache *kmem_cache_create(const char *name, size_t size,
+ size_t align, unsigned long flags,
+ void (*ctor)(void *, struct kmem_cache *, unsigned long),
+ void (*dtor)(void *, struct kmem_cache *, unsigned long))
+{
+ struct kmem_cache *s;
+
+ down_write(&slub_lock);
+ s = find_mergeable(size, align, flags, dtor, ctor);
+ if (s) {
+ s = kmem_cache_dup(s, GFP_KERNEL, name);
+ if (s)
+ goto out;
+
+ }
+ s = kmalloc(kmem_size, GFP_KERNEL);
+ if (s && kmem_cache_open(s, GFP_KERNEL, name,
+ size, align, flags, ctor, dtor)) {
+ list_add(&s->list, &slab_caches);
+ } else
+ kfree(s);
+out:
+ up_write(&slub_lock);
+ return s;
+}
+EXPORT_SYMBOL(kmem_cache_create);
+
+void *kmem_cache_zalloc(struct kmem_cache *s, gfp_t flags)
+{
+ void *x;
+
+ x = kmem_cache_alloc(s, flags);
+ if (x)
+ memset(x, 0, s->objsize);
+ return x;
+}
+EXPORT_SYMBOL(kmem_cache_zalloc);
+
+/********************************************************************
+ * Slab proc interface
+ *******************************************************************/
+
+static void print_slubinfo_header(struct seq_file *m)
+{
+ /*
+ * Output format version, so at least we can change it
+ * without _too_ many complaints.
+ */
+ seq_puts(m, "slubinfo - version: 1.0\n");
+ seq_puts(m, "# name <objects> <order> <objsize> <objperslab>"
+ " <slabs>/<partial>/<cpu> <flags>");
+#ifdef CONFIG_NUMA
+ seq_puts(m, " <nodes>");
+#endif
+ seq_putc(m, '\n');
+}
+
+static void *s_start(struct seq_file *m, loff_t *pos)
+{
+ loff_t n = *pos;
+ struct list_head *p;
+
+ down_read(&slub_lock);
+ if (!n)
+ print_slubinfo_header(m);
+ p = slab_caches.next;
+ while (n--) {
+ p = p->next;
+ if (p == &slab_caches)
+ return NULL;
+ }
+ return list_entry(p, struct kmem_cache, list);
+}
+
+static void *s_next(struct seq_file *m, void *p, loff_t *pos)
+{
+ struct kmem_cache *s = p;
+ ++*pos;
+ return s->list.next == &slab_caches ?
+ NULL : list_entry(s->list.next, struct kmem_cache, list);
+}
+
+static void s_stop(struct seq_file *m, void *p)
+{
+ up_read(&slub_lock);
+}
+
+static void display_nodes(struct seq_file *m, unsigned long *nodes)
+{
+#ifdef CONFIG_NUMA
+ int node;
+
+ for_each_online_node(node)
+ if (nodes[node])
+ seq_printf(m, " N%d=%lu", node, nodes[node]);
+#endif
+}
+
+static int s_show(struct seq_file *m, void *p)
+{
+ struct kmem_cache *s = p;
+ unsigned long total_slabs;
+ unsigned long cpu_slabs;
+ unsigned long partial_slabs;
+ unsigned long objects;
+ unsigned char options[17];
+ char *d = options;
+ char *x;
+ unsigned long nodes[nr_node_ids];
+
+ objects = slab_objects(s, &total_slabs, &cpu_slabs,
+ &partial_slabs, nodes);
+ if (s->ctor)
+ *d++ = 'C';
+ if (s->dtor)
+ *d++ = 'D';
+ if (s->flags & SLAB_DESTROY_BY_RCU)
+ *d++ = 'R';
+ if (s->flags & SLAB_MEM_SPREAD)
+ *d++ = 'S';
+ if (s->flags & SLAB_CACHE_DMA)
+ *d++ = 'd';
+ if (s->flags & SLAB_RECLAIM_ACCOUNT)
+ *d++ = 'r';
+ if (s->flags & SLAB_PANIC)
+ *d++ = 'p';
+ if (s->flags & SLAB_HWCACHE_ALIGN)
+ *d++ = 'a';
+ if (s->flags & SLAB_MUST_HWCACHE_ALIGN)
+ *d++ = 'A';
+ if (s->flags & SLAB_DEBUG_FREE)
+ *d++ = 'F';
+ if (s->flags & SLAB_DEBUG_INITIAL)
+ *d++ = 'I';
+ if (s->flags & SLAB_STORE_USER)
+ *d++ = 'U';
+ if (s->flags & SLAB_RED_ZONE)
+ *d++ = 'Z';
+ if (s->flags & SLAB_POISON)
+ *d++ = 'P';
+ if (s->flags & SLAB_TRACE)
+ *d++ = 'T';
+
+ *d = 0;
+
+ x = kasprintf(GFP_KERNEL, "%lu/%lu/%lu", total_slabs, partial_slabs,
+ cpu_slabs);
+
+ seq_printf(m, "%-21s %6lu %1d %6u %4d %12s %7s",
+ s->name, objects, s->order, s->objsize, s->objects, x, options);
+
+ kfree(x);
+ display_nodes(m, nodes);
+ if (s->aliases) {
+ seq_putc(m, ' ');
+ seq_puts(m, s->aliases);
+ }
+ seq_putc(m, '\n');
+ return 0;
+}
+
+/*
+ * slabinfo_op - iterator that generates /proc/slabinfo
+ */
+struct seq_operations slubinfo_op = {
+ .start = s_start,
+ .next = s_next,
+ .stop = s_stop,
+ .show = s_show,
+};
+
+#ifdef CONFIG_SMP
+static void for_all_slabs(void (*func)(struct kmem_cache *, int), int cpu)
+{
+ struct list_head *h;
+
+ down_read(&slub_lock);
+ list_for_each(h, &slab_caches) {
+ struct kmem_cache *s =
+ container_of(h, struct kmem_cache, list);
+
+ func(s, cpu);
+ }
+ up_read(&slub_lock);
+}
+
+/*
+ * Use the cpu notifier to insure that the thresholds are recalculated
+ * when necessary.
+ */
+static int __cpuinit slab_cpuup_callback(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ long cpu = (long)hcpu;
+
+ switch (action) {
+ case CPU_UP_CANCELED:
+ case CPU_DEAD:
+ for_all_slabs(__flush_cpu_slab, cpu);
+ break;
+ default:
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block __cpuinitdata slab_notifier =
+ { &slab_cpuup_callback, NULL, 0 };
+
+#endif
+
+/***************************************************************
+ * Compatiblility definitions
+ **************************************************************/
+
+int kmem_cache_shrink(struct kmem_cache *s)
+{
+ flush_all(s);
+ return 0;
+}
+EXPORT_SYMBOL(kmem_cache_shrink);
+
+#ifdef CONFIG_NUMA
+
+/*****************************************************************
+ * Generic reaper used to support the page allocator
+ * (the cpu slabs are reaped by a per slab workqueue).
+ *
+ * Maybe move this to the page allocator?
+ ****************************************************************/
+
+static DEFINE_PER_CPU(unsigned long, reap_node);
+
+static void init_reap_node(int cpu)
+{
+ int node;
+
+ node = next_node(cpu_to_node(cpu), node_online_map);
+ if (node == MAX_NUMNODES)
+ node = first_node(node_online_map);
+
+ __get_cpu_var(reap_node) = node;
+}
+
+static void next_reap_node(void)
+{
+ int node = __get_cpu_var(reap_node);
+
+ /*
+ * Also drain per cpu pages on remote zones
+ */
+ if (node != numa_node_id())
+ drain_node_pages(node);
+
+ node = next_node(node, node_online_map);
+ if (unlikely(node >= MAX_NUMNODES))
+ node = first_node(node_online_map);
+ __get_cpu_var(reap_node) = node;
+}
+#else
+#define init_reap_node(cpu) do { } while (0)
+#define next_reap_node(void) do { } while (0)
+#endif
+
+#define REAPTIMEOUT_CPUC (2*HZ)
+
+#ifdef CONFIG_SMP
+static DEFINE_PER_CPU(struct delayed_work, reap_work);
+
+static void cache_reap(struct work_struct *unused)
+{
+ next_reap_node();
+ refresh_cpu_vm_stats(smp_processor_id());
+ schedule_delayed_work(&__get_cpu_var(reap_work),
+ REAPTIMEOUT_CPUC);
+}
+
+static void __devinit start_cpu_timer(int cpu)
+{
+ struct delayed_work *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->work.func == NULL) {
+ init_reap_node(cpu);
+ INIT_DELAYED_WORK(reap_work, cache_reap);
+ schedule_delayed_work_on(cpu, reap_work, HZ + 3 * cpu);
+ }
+}
+
+static int __init cpucache_init(void)
+{
+ int cpu;
+
+ /*
+ * Register the timers that drain pcp pages and update vm statistics
+ */
+ for_each_online_cpu(cpu)
+ start_cpu_timer(cpu);
+ return 0;
+}
+__initcall(cpucache_init);
+#endif
+