Thread (37 messages) flat view 37 messages, 5 authors, 2012-02-13
STALE5301d

[PATCH 12/15] mm: Micro-optimise slab to avoid a function call

From: Mel Gorman <mgorman@suse.de>
Date: 2012-02-06 22:56:35
Also in: linux-mm, lkml
Subsystem: memory management, the rest · Maintainers: Andrew Morton, Linus Torvalds

Getting and putting objects in SLAB currently requires a function call
but the bulk of the work is related to PFMEMALLOC reserves which are
only consumed when network-backed storage is critical. Use an inline
function to determine if the function call is required.

Signed-off-by: Mel Gorman <mgorman@suse.de>
---
 mm/slab.c |   28 ++++++++++++++++++++++++++--
 1 files changed, 26 insertions(+), 2 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index 95c96b9..268cd96 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -117,6 +117,8 @@
 #include	<linux/memory.h>
 #include	<linux/prefetch.h>
 
+#include	<net/sock.h>
+
 #include	<asm/cacheflush.h>
 #include	<asm/tlbflush.h>
 #include	<asm/page.h>
@@ -1001,7 +1003,7 @@ static void check_ac_pfmemalloc(struct kmem_cache *cachep,
 	ac->pfmemalloc = false;
 }
 
-static void *ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
+static void *__ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
 						gfp_t flags, bool force_refill)
 {
 	int i;
@@ -1048,7 +1050,20 @@ static void *ac_get_obj(struct kmem_cache *cachep, struct array_cache *ac,
 	return objp;
 }
 
-static void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
+static inline void *ac_get_obj(struct kmem_cache *cachep,
+			struct array_cache *ac, gfp_t flags, bool force_refill)
+{
+	void *objp;
+
+	if (unlikely(sk_memalloc_socks()))
+		objp = __ac_get_obj(cachep, ac, flags, force_refill);
+	else
+		objp = ac->entry[--ac->avail];
+
+	return objp;
+}
+
+static void *__ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
 								void *objp)
 {
 	struct slab *slabp;
@@ -1061,6 +1076,15 @@ static void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
 			set_obj_pfmemalloc(&objp);
 	}
 
+	return objp;
+}
+
+static inline void ac_put_obj(struct kmem_cache *cachep, struct array_cache *ac,
+								void *objp)
+{
+	if (unlikely(sk_memalloc_socks()))
+		objp = __ac_put_obj(cachep, ac, objp);
+
 	ac->entry[ac->avail++] = objp;
 }
 
-- 
1.7.3.4
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