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SLUB: Get rid of dynamic DMA kmalloc cache allocation

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Dynamic DMA kmalloc cache allocation is troublesome since the
new percpu allocator does not support allocations in atomic contexts.
Reserve some statically allocated kmalloc_cpu structures instead.

Signed-off-by: Christoph Lameter <cl@linux-foundation.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
This commit is contained in:
Christoph Lameter 2009-12-18 16:26:21 -06:00 committed by Pekka Enberg
parent 9dfc6e68bf
commit 756dee7587
2 changed files with 21 additions and 22 deletions
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19
include/linux/slub_def.h
View File

@ -131,11 +131,21 @@ struct kmem_cache {
#define SLUB_PAGE_SHIFT (PAGE_SHIFT + 2)
#ifdef CONFIG_ZONE_DMA
#define SLUB_DMA __GFP_DMA
/* Reserve extra caches for potential DMA use */
#define KMALLOC_CACHES (2 * SLUB_PAGE_SHIFT - 6)
#else
/* Disable DMA functionality */
#define SLUB_DMA (__force gfp_t)0
#define KMALLOC_CACHES SLUB_PAGE_SHIFT
#endif
/*
* 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[SLUB_PAGE_SHIFT];
extern struct kmem_cache kmalloc_caches[KMALLOC_CACHES];
/*
* Sorry that the following has to be that ugly but some versions of GCC
@ -203,13 +213,6 @@ static __always_inline struct kmem_cache *kmalloc_slab(size_t size)
return &kmalloc_caches[index];
}
#ifdef CONFIG_ZONE_DMA
#define SLUB_DMA __GFP_DMA
#else
/* Disable DMA functionality */
#define SLUB_DMA (__force gfp_t)0
#endif
void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
void *__kmalloc(size_t size, gfp_t flags);

24
mm/slub.c
View File

@ -2092,7 +2092,7 @@ static inline int alloc_kmem_cache_cpus(struct kmem_cache *s, gfp_t flags)
{
int cpu;
if (s < kmalloc_caches + SLUB_PAGE_SHIFT && s >= kmalloc_caches)
if (s < kmalloc_caches + KMALLOC_CACHES && s >= kmalloc_caches)
/*
* Boot time creation of the kmalloc array. Use static per cpu data
* since the per cpu allocator is not available yet.
@ -2539,7 +2539,7 @@ EXPORT_SYMBOL(kmem_cache_destroy);
* Kmalloc subsystem
*******************************************************************/
struct kmem_cache kmalloc_caches[SLUB_PAGE_SHIFT] __cacheline_aligned;
struct kmem_cache kmalloc_caches[KMALLOC_CACHES] __cacheline_aligned;
EXPORT_SYMBOL(kmalloc_caches);
static int __init setup_slub_min_order(char *str)
@ -2629,6 +2629,7 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
char *text;
size_t realsize;
unsigned long slabflags;
int i;
s = kmalloc_caches_dma[index];
if (s)
@ -2649,18 +2650,13 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
text = kasprintf(flags & ~SLUB_DMA, "kmalloc_dma-%d",
(unsigned int)realsize);
if (flags & __GFP_WAIT)
s = kmalloc(kmem_size, flags & ~SLUB_DMA);
else {
int i;
s = NULL;
for (i = 0; i < KMALLOC_CACHES; i++)
if (!kmalloc_caches[i].size)
break;
s = NULL;
for (i = 0; i < SLUB_PAGE_SHIFT; i++)
if (kmalloc_caches[i].size) {
s = kmalloc_caches + i;
break;
}
}
BUG_ON(i >= KMALLOC_CACHES);
s = kmalloc_caches + i;
/*
* Must defer sysfs creation to a workqueue because we don't know
@ -2674,7 +2670,7 @@ static noinline struct kmem_cache *dma_kmalloc_cache(int index, gfp_t flags)
if (!s || !text || !kmem_cache_open(s, flags, text,
realsize, ARCH_KMALLOC_MINALIGN, slabflags, NULL)) {
kfree(s);
s->size = 0;
kfree(text);
goto unlock_out;
}