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 <[email protected]>
---
include/linux/slub_def.h | 19 +++++++++++--------
mm/slub.c | 24 ++++++++++--------------
2 files changed, 21 insertions(+), 22 deletions(-)
Index: linux-2.6/include/linux/slub_def.h
===================================================================
--- linux-2.6.orig/include/linux/slub_def.h 2009-09-29 11:42:06.000000000 -0500
+++ linux-2.6/include/linux/slub_def.h 2009-09-29 11:43:18.000000000 -0500
@@ -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
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);
Index: linux-2.6/mm/slub.c
===================================================================
--- linux-2.6.orig/mm/slub.c 2009-09-29 11:42:06.000000000 -0500
+++ linux-2.6/mm/slub.c 2009-09-29 11:43:18.000000000 -0500
@@ -2090,7 +2090,7 @@ static inline int alloc_kmem_cache_cpus(
{
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.
@@ -2537,7 +2537,7 @@ 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)
@@ -2627,6 +2627,7 @@ static noinline struct kmem_cache *dma_k
char *text;
size_t realsize;
unsigned long slabflags;
+ int i;
s = kmalloc_caches_dma[index];
if (s)
@@ -2647,18 +2648,13 @@ static noinline struct kmem_cache *dma_k
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
@@ -2672,7 +2668,7 @@ static noinline struct kmem_cache *dma_k
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;
}
--