The patch titled
Subject: mm: don't call should_failslab() for !CONFIG_FAILSLAB
has been added to the -mm tree. Its filename is
mm-dont-call-should_failslab-for-config_failslab.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-dont-call-should_failslab-for-config_failslab.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-dont-call-should_failslab-for-config_failslab.patch
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------------------------------------------------------
From: Jens Axboe <axboe@xxxxxxxxx>
Subject: mm: don't call should_failslab() for !CONFIG_FAILSLAB
Allocations can be a very hot path, and this out-of-line function
call is noticeable.
Link: https://lkml.kernel.org/r/e01e5e40-692a-519c-4cba-e3331f173c82@xxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Cc: Christoph Lameter <cl@xxxxxxxxx>
Cc: Pekka Enberg <penberg@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Joonsoo Kim <iamjoonsoo.kim@xxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/fault-inject.h | 2 +-
mm/slab.h | 2 ++
mm/slab_common.c | 2 ++
3 files changed, 5 insertions(+), 1 deletion(-)
--- a/include/linux/fault-inject.h~mm-dont-call-should_failslab-for-config_failslab
+++ a/include/linux/fault-inject.h
@@ -64,8 +64,8 @@ static inline struct dentry *fault_creat
struct kmem_cache;
-int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
#ifdef CONFIG_FAILSLAB
+int should_failslab(struct kmem_cache *s, gfp_t gfpflags);
extern bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags);
#else
static inline bool __should_failslab(struct kmem_cache *s, gfp_t gfpflags)
--- a/mm/slab_common.c~mm-dont-call-should_failslab-for-config_failslab
+++ a/mm/slab_common.c
@@ -1323,6 +1323,7 @@ EXPORT_TRACEPOINT_SYMBOL(kmem_cache_allo
EXPORT_TRACEPOINT_SYMBOL(kfree);
EXPORT_TRACEPOINT_SYMBOL(kmem_cache_free);
+#ifdef CONFIG_FAILSLAB
int should_failslab(struct kmem_cache *s, gfp_t gfpflags)
{
if (__should_failslab(s, gfpflags))
@@ -1330,3 +1331,4 @@ int should_failslab(struct kmem_cache *s
return 0;
}
ALLOW_ERROR_INJECTION(should_failslab, ERRNO);
+#endif
--- a/mm/slab.h~mm-dont-call-should_failslab-for-config_failslab
+++ a/mm/slab.h
@@ -491,8 +491,10 @@ static inline struct kmem_cache *slab_pr
might_alloc(flags);
+#ifdef CONFIG_FAILSLAB
if (should_failslab(s, flags))
return NULL;
+#endif
if (!memcg_slab_pre_alloc_hook(s, objcgp, size, flags))
return NULL;
_
Patches currently in -mm which might be from axboe@xxxxxxxxx are
mm-dont-call-should_failslab-for-config_failslab.patch
