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* + slub-reduce-duplicate-creation-on-the-first-object.patch added to -mm tree
@ 2014-06-24 21:56 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2014-06-24 21:56 UTC (permalink / raw
  To: weiyang, cl, iamjoonsoo.kim, penberg, rientjes, mm-commits


The patch titled
     Subject: slub: reduce duplicate creation on the first object
has been added to the -mm tree.  Its filename is
     slub-reduce-duplicate-creation-on-the-first-object.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/slub-reduce-duplicate-creation-on-the-first-object.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/slub-reduce-duplicate-creation-on-the-first-object.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/SubmitChecklist when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Wei Yang <weiyang@linux.vnet.ibm.com>
Subject: slub: reduce duplicate creation on the first object

When a kmem_cache is created with ctor, each object in the kmem_cache will
be initialized before use.  In the slub implementation, the first object
will be initialized twice.

This patch avoids the duplication of initialization of the first object.

Fixes commit 7656c72b5a63: ("SLUB: add macros for scanning objects in a
slab").

Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/slub.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff -puN mm/slub.c~slub-reduce-duplicate-creation-on-the-first-object mm/slub.c
--- a/mm/slub.c~slub-reduce-duplicate-creation-on-the-first-object
+++ a/mm/slub.c
@@ -1403,7 +1403,7 @@ static struct page *new_slab(struct kmem
 		memset(start, POISON_INUSE, PAGE_SIZE << order);
 
 	last = start;
-	for_each_object(p, s, start, page->objects) {
+	for_each_object(p, s, start + s->size, page->objects - 1) {
 		setup_object(s, page, last);
 		set_freepointer(s, last, p);
 		last = p;
_

Patches currently in -mm which might be from weiyang@linux.vnet.ibm.com are

slub-reduce-duplicate-creation-on-the-first-object.patch


^ permalink raw reply	[flat|nested] 2+ messages in thread

* + slub-reduce-duplicate-creation-on-the-first-object.patch added to -mm tree
@ 2014-07-07 19:10 akpm
  0 siblings, 0 replies; 2+ messages in thread
From: akpm @ 2014-07-07 19:10 UTC (permalink / raw
  To: weiyang, cl, iamjoonsoo.kim, penberg, rientjes, mm-commits


The patch titled
     Subject: slub: avoid duplicate creation on the first object
has been added to the -mm tree.  Its filename is
     slub-reduce-duplicate-creation-on-the-first-object.patch

This patch should soon appear at
    http://ozlabs.org/~akpm/mmots/broken-out/slub-reduce-duplicate-creation-on-the-first-object.patch
and later at
    http://ozlabs.org/~akpm/mmotm/broken-out/slub-reduce-duplicate-creation-on-the-first-object.patch

Before you just go and hit "reply", please:
   a) Consider who else should be cc'ed
   b) Prefer to cc a suitable mailing list as well
   c) Ideally: find the original patch on the mailing list and do a
      reply-to-all to that, adding suitable additional cc's

*** Remember to use Documentation/SubmitChecklist when testing your code ***

The -mm tree is included into linux-next and is updated
there every 3-4 working days

------------------------------------------------------
From: Wei Yang <weiyang@linux.vnet.ibm.com>
Subject: slub: avoid duplicate creation on the first object

When a kmem_cache is created with ctor, each object in the kmem_cache will
be initialized before ready to use.  While in slub implementation, the
first object will be initialized twice.

This patch reduces the duplication of initialization of the first object.

Fix commit 7656c72b ("SLUB: add macros for scanning objects in a slab").

Signed-off-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/slub.c |   19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff -puN mm/slub.c~slub-reduce-duplicate-creation-on-the-first-object mm/slub.c
--- a/mm/slub.c~slub-reduce-duplicate-creation-on-the-first-object
+++ a/mm/slub.c
@@ -283,6 +283,10 @@ static inline void set_freepointer(struc
 	for (__p = (__addr); __p < (__addr) + (__objects) * (__s)->size;\
 			__p += (__s)->size)
 
+#define for_each_object_idx(__p, __idx, __s, __addr, __objects) \
+	for (__p = (__addr), __idx = 1; __idx <= __objects;\
+			__p += (__s)->size, __idx++)
+
 /* Determine object index from a given position */
 static inline int slab_index(void *p, struct kmem_cache *s, void *addr)
 {
@@ -1379,9 +1383,9 @@ static struct page *new_slab(struct kmem
 {
 	struct page *page;
 	void *start;
-	void *last;
 	void *p;
 	int order;
+	int idx;
 
 	BUG_ON(flags & GFP_SLAB_BUG_MASK);
 
@@ -1402,14 +1406,13 @@ static struct page *new_slab(struct kmem
 	if (unlikely(s->flags & SLAB_POISON))
 		memset(start, POISON_INUSE, PAGE_SIZE << order);
 
-	last = start;
-	for_each_object(p, s, start, page->objects) {
-		setup_object(s, page, last);
-		set_freepointer(s, last, p);
-		last = p;
+	for_each_object_idx(p, idx, s, start, page->objects) {
+		setup_object(s, page, p);
+		if (likely(idx < page->objects))
+			set_freepointer(s, p, p + s->size);
+		else
+			set_freepointer(s, p, NULL);
 	}
-	setup_object(s, page, last);
-	set_freepointer(s, last, NULL);
 
 	page->freelist = start;
 	page->inuse = page->objects;
_

Patches currently in -mm which might be from weiyang@linux.vnet.ibm.com are

slub-reduce-duplicate-creation-on-the-first-object.patch


^ permalink raw reply	[flat|nested] 2+ messages in thread

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