summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorChristoph Lameter <cl@linux-foundation.org>2009-12-18 16:26:21 -0600
committerPekka Enberg <penberg@cs.helsinki.fi>2009-12-20 09:57:00 +0200
commit756dee75872a2a764b478e18076360b8a4ec9045 (patch)
treec4a09707be2f926631815dec98b0e0f3f4b9ae20
parent9dfc6e68bfe6ee452efb1a4e9ca26a9007f2b864 (diff)
downloadop-kernel-dev-756dee75872a2a764b478e18076360b8a4ec9045.zip
op-kernel-dev-756dee75872a2a764b478e18076360b8a4ec9045.tar.gz
SLUB: Get rid of dynamic DMA kmalloc cache allocation
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>
-rw-r--r--include/linux/slub_def.h19
-rw-r--r--mm/slub.c24
2 files changed, 21 insertions, 22 deletions
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index 17ebe0f..a78fb4a 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -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);
diff --git a/mm/slub.c b/mm/slub.c
index d6c9ecf..cdb7f02 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -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;
}
OpenPOWER on IntegriCloud