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slub: Dynamically size kmalloc cache allocations

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kmalloc caches are statically defined and may take up a lot of space just
because the sizes of the node array has to be dimensioned for the largest
node count supported.

This patch makes the size of the kmem_cache structure dynamic throughout by
creating a kmem_cache slab cache for the kmem_cache objects. The bootstrap
occurs by allocating the initial one or two kmem_cache objects from the
page allocator.

C2->C3
	- Fix various issues indicated by David
	- Make create kmalloc_cache return a kmem_cache * pointer.

Acked-by: David Rientjes <rientjes@google.com>
Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
This commit is contained in:
Christoph Lameter 2010-08-20 12:37:15 -05:00 committed by Pekka Enberg
parent 6c182dc0de
commit 51df114281
2 changed files with 140 additions and 58 deletions
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7
include/linux/slub_def.h
View File

@ -139,19 +139,16 @@ struct kmem_cache {
#ifdef CONFIG_ZONE_DMA #ifdef CONFIG_ZONE_DMA
#define SLUB_DMA __GFP_DMA #define SLUB_DMA __GFP_DMA
/* Reserve extra caches for potential DMA use */
#define KMALLOC_CACHES (2 * SLUB_PAGE_SHIFT)
#else #else
/* Disable DMA functionality */ /* Disable DMA functionality */
#define SLUB_DMA (__force gfp_t)0 #define SLUB_DMA (__force gfp_t)0
#define KMALLOC_CACHES SLUB_PAGE_SHIFT
#endif #endif
/* /*
* We keep the general caches in an array of slab caches that are used for * We keep the general caches in an array of slab caches that are used for
* 2^x bytes of allocations. * 2^x bytes of allocations.
*/ */
extern struct kmem_cache kmalloc_caches[KMALLOC_CACHES]; extern struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
/* /*
* Sorry that the following has to be that ugly but some versions of GCC * Sorry that the following has to be that ugly but some versions of GCC
@ -216,7 +213,7 @@ static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
if (index == 0) if (index == 0)
return NULL; return NULL;
return &kmalloc_caches[index]; return kmalloc_caches[index];
} }
void *kmem_cache_alloc(struct kmem_cache *, gfp_t); void *kmem_cache_alloc(struct kmem_cache *, gfp_t);

191
mm/slub.c
View File

@ -168,7 +168,6 @@ static inline int kmem_cache_debug(struct kmem_cache *s)
/* Internal SLUB flags */ /* Internal SLUB flags */
#define __OBJECT_POISON 0x80000000UL /* Poison object */ #define __OBJECT_POISON 0x80000000UL /* Poison object */
#define __SYSFS_ADD_DEFERRED 0x40000000UL /* Not yet visible via sysfs */
static int kmem_size = sizeof(struct kmem_cache); static int kmem_size = sizeof(struct kmem_cache);
@ -178,7 +177,7 @@ static struct notifier_block slab_notifier;
static enum { static enum {
DOWN, /* No slab functionality available */ DOWN, /* No slab functionality available */
PARTIAL, /* kmem_cache_open() works but kmalloc does not */ PARTIAL, /* Kmem_cache_node works */
UP, /* Everything works but does not show up in sysfs */ UP, /* Everything works but does not show up in sysfs */
SYSFS /* Sysfs up */ SYSFS /* Sysfs up */
} slab_state = DOWN; } slab_state = DOWN;
@ -2073,6 +2072,8 @@ static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
} }
#ifdef CONFIG_NUMA #ifdef CONFIG_NUMA
static struct kmem_cache *kmem_cache_node;
/* /*
* No kmalloc_node yet so do it by hand. We know that this is the first * 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 * slab on the node for this slabcache. There are no concurrent accesses
@ -2088,9 +2089,9 @@ static void early_kmem_cache_node_alloc(int node)
struct kmem_cache_node *n; struct kmem_cache_node *n;
unsigned long flags; unsigned long flags;
BUG_ON(kmalloc_caches->size < sizeof(struct kmem_cache_node)); BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
page = new_slab(kmalloc_caches, GFP_NOWAIT, node); page = new_slab(kmem_cache_node, GFP_NOWAIT, node);
BUG_ON(!page); BUG_ON(!page);
if (page_to_nid(page) != node) { if (page_to_nid(page) != node) {
@ -2102,15 +2103,15 @@ static void early_kmem_cache_node_alloc(int node)
n = page->freelist; n = page->freelist;
BUG_ON(!n); BUG_ON(!n);
page->freelist = get_freepointer(kmalloc_caches, n); page->freelist = get_freepointer(kmem_cache_node, n);
page->inuse++; page->inuse++;
kmalloc_caches->node[node] = n; kmem_cache_node->node[node] = n;
#ifdef CONFIG_SLUB_DEBUG #ifdef CONFIG_SLUB_DEBUG
init_object(kmalloc_caches, n, 1); init_object(kmem_cache_node, n, 1);
init_tracking(kmalloc_caches, n); init_tracking(kmem_cache_node, n);
#endif #endif
init_kmem_cache_node(n, kmalloc_caches); init_kmem_cache_node(n, kmem_cache_node);
inc_slabs_node(kmalloc_caches, node, page->objects); inc_slabs_node(kmem_cache_node, node, page->objects);
/* /*
* lockdep requires consistent irq usage for each lock * lockdep requires consistent irq usage for each lock
@ -2128,8 +2129,10 @@ static void free_kmem_cache_nodes(struct kmem_cache *s)
for_each_node_state(node, N_NORMAL_MEMORY) { for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n = s->node[node]; struct kmem_cache_node *n = s->node[node];
if (n) if (n)
kmem_cache_free(kmalloc_caches, n); kmem_cache_free(kmem_cache_node, n);
s->node[node] = NULL; s->node[node] = NULL;
} }
} }
@ -2145,7 +2148,7 @@ static int init_kmem_cache_nodes(struct kmem_cache *s)
early_kmem_cache_node_alloc(node); early_kmem_cache_node_alloc(node);
continue; continue;
} }
n = kmem_cache_alloc_node(kmalloc_caches, n = kmem_cache_alloc_node(kmem_cache_node,
GFP_KERNEL, node); GFP_KERNEL, node);
if (!n) { if (!n) {
@ -2498,11 +2501,13 @@ EXPORT_SYMBOL(kmem_cache_destroy);
* Kmalloc subsystem * Kmalloc subsystem
*******************************************************************/ *******************************************************************/
struct kmem_cache kmalloc_caches[KMALLOC_CACHES] __cacheline_aligned; struct kmem_cache *kmalloc_caches[SLUB_PAGE_SHIFT];
EXPORT_SYMBOL(kmalloc_caches); EXPORT_SYMBOL(kmalloc_caches);
static struct kmem_cache *kmem_cache;
#ifdef CONFIG_ZONE_DMA #ifdef CONFIG_ZONE_DMA
static struct kmem_cache kmalloc_dma_caches[SLUB_PAGE_SHIFT]; static struct kmem_cache *kmalloc_dma_caches[SLUB_PAGE_SHIFT];
#endif #endif
static int __init setup_slub_min_order(char *str) static int __init setup_slub_min_order(char *str)
@ -2541,9 +2546,13 @@ static int __init setup_slub_nomerge(char *str)
__setup("slub_nomerge", setup_slub_nomerge); __setup("slub_nomerge", setup_slub_nomerge);
static void create_kmalloc_cache(struct kmem_cache *s, static struct kmem_cache *__init create_kmalloc_cache(const char *name,
const char *name, int size, unsigned int flags) int size, unsigned int flags)
{ {
struct kmem_cache *s;
s = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
/* /*
* This function is called with IRQs disabled during early-boot on * This function is called with IRQs disabled during early-boot on
* single CPU so there's no need to take slub_lock here. * single CPU so there's no need to take slub_lock here.
@ -2553,12 +2562,11 @@ static void create_kmalloc_cache(struct kmem_cache *s,
goto panic; goto panic;
list_add(&s->list, &slab_caches); list_add(&s->list, &slab_caches);
return s;
if (!sysfs_slab_add(s))
return;
panic: panic:
panic("Creation of kmalloc slab %s size=%d failed.\n", name, size); panic("Creation of kmalloc slab %s size=%d failed.\n", name, size);
return NULL;
} }
/* /*
@ -2613,10 +2621,10 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags)
#ifdef CONFIG_ZONE_DMA #ifdef CONFIG_ZONE_DMA
if (unlikely((flags & SLUB_DMA))) if (unlikely((flags & SLUB_DMA)))
return &kmalloc_dma_caches[index]; return kmalloc_dma_caches[index];
#endif #endif
return &kmalloc_caches[index]; return kmalloc_caches[index];
} }
void *__kmalloc(size_t size, gfp_t flags) void *__kmalloc(size_t size, gfp_t flags)
@ -2940,46 +2948,113 @@ static int slab_memory_callback(struct notifier_block *self,
* Basic setup of slabs * Basic setup of slabs
*******************************************************************/ *******************************************************************/
/*
* Used for early kmem_cache structures that were allocated using
* the page allocator
*/
static void __init kmem_cache_bootstrap_fixup(struct kmem_cache *s)
{
int node;
list_add(&s->list, &slab_caches);
s->refcount = -1;
for_each_node_state(node, N_NORMAL_MEMORY) {
struct kmem_cache_node *n = get_node(s, node);
struct page *p;
if (n) {
list_for_each_entry(p, &n->partial, lru)
p->slab = s;
#ifdef CONFIG_SLAB_DEBUG
list_for_each_entry(p, &n->full, lru)
p->slab = s;
#endif
}
}
}
void __init kmem_cache_init(void) void __init kmem_cache_init(void)
{ {
int i; int i;
int caches = 0; int caches = 0;
struct kmem_cache *temp_kmem_cache;
int order;
#ifdef CONFIG_NUMA #ifdef CONFIG_NUMA
struct kmem_cache *temp_kmem_cache_node;
unsigned long kmalloc_size;
kmem_size = offsetof(struct kmem_cache, node) +
nr_node_ids * sizeof(struct kmem_cache_node *);
/* Allocate two kmem_caches from the page allocator */
kmalloc_size = ALIGN(kmem_size, cache_line_size());
order = get_order(2 * kmalloc_size);
kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
/* /*
* Must first have the slab cache available for the allocations of the * Must first have the slab cache available for the allocations of the
* struct kmem_cache_node's. There is special bootstrap code in * struct kmem_cache_node's. There is special bootstrap code in
* kmem_cache_open for slab_state == DOWN. * kmem_cache_open for slab_state == DOWN.
*/ */
create_kmalloc_cache(&kmalloc_caches[0], "kmem_cache_node", kmem_cache_node = (void *)kmem_cache + kmalloc_size;
sizeof(struct kmem_cache_node), 0);
kmalloc_caches[0].refcount = -1; kmem_cache_open(kmem_cache_node, "kmem_cache_node",
caches++; sizeof(struct kmem_cache_node),
0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI); hotplug_memory_notifier(slab_memory_callback, SLAB_CALLBACK_PRI);
#else
/* Allocate a single kmem_cache from the page allocator */
kmem_size = sizeof(struct kmem_cache);
order = get_order(kmem_size);
kmem_cache = (void *)__get_free_pages(GFP_NOWAIT, order);
#endif #endif
/* Able to allocate the per node structures */ /* Able to allocate the per node structures */
slab_state = PARTIAL; slab_state = PARTIAL;
/* Caches that are not of the two-to-the-power-of size */ temp_kmem_cache = kmem_cache;
if (KMALLOC_MIN_SIZE <= 32) { kmem_cache_open(kmem_cache, "kmem_cache", kmem_size,
create_kmalloc_cache(&kmalloc_caches[1], 0, SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
"kmalloc-96", 96, 0); kmem_cache = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
caches++; memcpy(kmem_cache, temp_kmem_cache, kmem_size);
}
if (KMALLOC_MIN_SIZE <= 64) {
create_kmalloc_cache(&kmalloc_caches[2],
"kmalloc-192", 192, 0);
caches++;
}
for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) { #ifdef CONFIG_NUMA
create_kmalloc_cache(&kmalloc_caches[i], /*
"kmalloc", 1 << i, 0); * Allocate kmem_cache_node properly from the kmem_cache slab.
caches++; * kmem_cache_node is separately allocated so no need to
} * update any list pointers.
*/
temp_kmem_cache_node = kmem_cache_node;
kmem_cache_node = kmem_cache_alloc(kmem_cache, GFP_NOWAIT);
memcpy(kmem_cache_node, temp_kmem_cache_node, kmem_size);
kmem_cache_bootstrap_fixup(kmem_cache_node);
caches++;
#else
/*
* kmem_cache has kmem_cache_node embedded and we moved it!
* Update the list heads
*/
INIT_LIST_HEAD(&kmem_cache->local_node.partial);
list_splice(&temp_kmem_cache->local_node.partial, &kmem_cache->local_node.partial);
#ifdef CONFIG_SLUB_DEBUG
INIT_LIST_HEAD(&kmem_cache->local_node.full);
list_splice(&temp_kmem_cache->local_node.full, &kmem_cache->local_node.full);
#endif
#endif
kmem_cache_bootstrap_fixup(kmem_cache);
caches++;
/* Free temporary boot structure */
free_pages((unsigned long)temp_kmem_cache, order);
/* Now we can use the kmem_cache to allocate kmalloc slabs */
/* /*
* Patch up the size_index table if we have strange large alignment * Patch up the size_index table if we have strange large alignment
@ -3019,6 +3094,22 @@ void __init kmem_cache_init(void)
size_index[size_index_elem(i)] = 8; size_index[size_index_elem(i)] = 8;
} }
/* Caches that are not of the two-to-the-power-of size */
if (KMALLOC_MIN_SIZE <= 32) {
kmalloc_caches[1] = create_kmalloc_cache("kmalloc-96", 96, 0);
caches++;
}
if (KMALLOC_MIN_SIZE <= 64) {
kmalloc_caches[2] = create_kmalloc_cache("kmalloc-192", 192, 0);
caches++;
}
for (i = KMALLOC_SHIFT_LOW; i < SLUB_PAGE_SHIFT; i++) {
kmalloc_caches[i] = create_kmalloc_cache("kmalloc", 1 << i, 0);
caches++;
}
slab_state = UP; slab_state = UP;
/* Provide the correct kmalloc names now that the caches are up */ /* Provide the correct kmalloc names now that the caches are up */
@ -3026,30 +3117,24 @@ void __init kmem_cache_init(void)
char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i); char *s = kasprintf(GFP_NOWAIT, "kmalloc-%d", 1 << i);
BUG_ON(!s); BUG_ON(!s);
kmalloc_caches[i].name = s; kmalloc_caches[i]->name = s;
} }
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
register_cpu_notifier(&slab_notifier); register_cpu_notifier(&slab_notifier);
#endif #endif
#ifdef CONFIG_NUMA
kmem_size = offsetof(struct kmem_cache, node) +
nr_node_ids * sizeof(struct kmem_cache_node *);
#else
kmem_size = sizeof(struct kmem_cache);
#endif
#ifdef CONFIG_ZONE_DMA #ifdef CONFIG_ZONE_DMA
for (i = 1; i < SLUB_PAGE_SHIFT; i++) { for (i = 0; i < SLUB_PAGE_SHIFT; i++) {
struct kmem_cache *s = &kmalloc_caches[i]; struct kmem_cache *s = kmalloc_caches[i];
if (s->size) { if (s && s->size) {
char *name = kasprintf(GFP_NOWAIT, char *name = kasprintf(GFP_NOWAIT,
"dma-kmalloc-%d", s->objsize); "dma-kmalloc-%d", s->objsize);
BUG_ON(!name); BUG_ON(!name);
create_kmalloc_cache(&kmalloc_dma_caches[i], kmalloc_dma_caches[i] = create_kmalloc_cache(name,
name, s->objsize, SLAB_CACHE_DMA); s->objsize, SLAB_CACHE_DMA);
} }
} }
#endif #endif