pull in some SLUB fixes from Mel Gorman for testing

kernel.spec

@@ -711,6 +711,10 @@ Patch12205: runtime_pm_fixups.patch
 
 Patch12303: dmar-disable-when-ricoh-multifunction.patch
 
+Patch12400: mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocations.patch
+Patch12401: mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch
+Patch12402: mm-slub-default-slub_max_order-to-0.patch
+
 %endif
 
 BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@@ -1317,6 +1321,10 @@ ApplyPatch acpi_reboot.patch
 # rhbz#605888
 ApplyPatch dmar-disable-when-ricoh-multifunction.patch
 
+ApplyPatch mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocations.patch
+ApplyPatch mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch
+ApplyPatch mm-slub-default-slub_max_order-to-0.patch
+
 # END OF PATCH APPLICATIONS
 
 %endif
@@ -1925,6 +1933,9 @@ fi
 # and build.
 
 %changelog
+* Wed May 11 2011 Kyle McMartin <kmcmartin@redhat.com>
+- Pull in some SLUB fixes from Mel Gorman for testing.
+
 * Tue May 09 2011 Kyle McMartin <kmcmartin@redhat.com> 2.6.39-0.rc7.git0.0
 - Linux 2.6.39-rc7
 

mm-slub-default-slub_max_order-to-0.patch

@@ -0,0 +1,67 @@
+From owner-linux-mm@kvack.org Wed May 11 11:35:30 2011
+From: Mel Gorman <mgorman@suse.de>
+To: Andrew Morton <akpm@linux-foundation.org>
+Subject: [PATCH 3/3] mm: slub: Default slub_max_order to 0
+Date: Wed, 11 May 2011 16:29:33 +0100
+Message-Id: <1305127773-10570-4-git-send-email-mgorman@suse.de>
+
+To avoid locking and per-cpu overhead, SLUB optimisically uses
+high-order allocations up to order-3 by default and falls back to
+lower allocations if they fail. While care is taken that the caller
+and kswapd take no unusual steps in response to this, there are
+further consequences like shrinkers who have to free more objects to
+release any memory. There is anecdotal evidence that significant time
+is being spent looping in shrinkers with insufficient progress being
+made (https://lkml.org/lkml/2011/4/28/361) and keeping kswapd awake.
+
+SLUB is now the default allocator and some bug reports have been
+pinned down to SLUB using high orders during operations like
+copying large amounts of data. SLUBs use of high-orders benefits
+applications that are sized to memory appropriately but this does not
+necessarily apply to large file servers or desktops.  This patch
+causes SLUB to use order-0 pages like SLAB does by default.
+There is further evidence that this keeps kswapd's usage lower
+(https://lkml.org/lkml/2011/5/10/383).
+
+Signed-off-by: Mel Gorman <mgorman@suse.de>
+---
+ Documentation/vm/slub.txt |    2 +-
+ mm/slub.c                 |    2 +-
+ 2 files changed, 2 insertions(+), 2 deletions(-)
+
+diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
+index 07375e7..778e9fa 100644
+--- a/Documentation/vm/slub.txt
++++ b/Documentation/vm/slub.txt
+@@ -117,7 +117,7 @@ can be influenced by kernel parameters:
+ 
+ slub_min_objects=x		(default 4)
+ slub_min_order=x		(default 0)
+-slub_max_order=x		(default 1)
++slub_max_order=x		(default 0)
+ 
+ slub_min_objects allows to specify how many objects must at least fit
+ into one slab in order for the allocation order to be acceptable.
+diff --git a/mm/slub.c b/mm/slub.c
+index 1071723..23a4789 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -2198,7 +2198,7 @@ EXPORT_SYMBOL(kmem_cache_free);
+  * take the list_lock.
+  */
+ static int slub_min_order;
+-static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
++static int slub_max_order;
+ static int slub_min_objects;
+ 
+ /*
+-- 
+1.7.3.4
+
+--
+To unsubscribe, send a message with 'unsubscribe linux-mm' in
+the body to majordomo@kvack.org.  For more info on Linux MM,
+see: http://www.linux-mm.org/ .
+Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
+Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
+

mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch

@@ -0,0 +1,73 @@
+From owner-linux-mm@kvack.org Wed May 11 11:29:53 2011
+From: Mel Gorman <mgorman@suse.de>
+To: Andrew Morton <akpm@linux-foundation.org>
+Subject: [PATCH 2/3] mm: slub: Do not take expensive steps for SLUBs speculative high-order allocations
+Date: Wed, 11 May 2011 16:29:32 +0100
+Message-Id: <1305127773-10570-3-git-send-email-mgorman@suse.de>
+
+To avoid locking and per-cpu overhead, SLUB optimisically uses
+high-order allocations and falls back to lower allocations if they
+fail. However, by simply trying to allocate, the caller can enter
+compaction or reclaim - both of which are likely to cost more than the
+benefit of using high-order pages in SLUB. On a desktop system, two
+users report that the system is getting stalled with kswapd using large
+amounts of CPU.
+
+This patch prevents SLUB taking any expensive steps when trying to
+use high-order allocations. Instead, it is expected to fall back to
+smaller orders more aggressively. Testing from users was somewhat
+inconclusive on how much this helped but local tests showed it made
+a positive difference. It makes sense that falling back to order-0
+allocations is faster than entering compaction or direct reclaim.
+
+Signed-off-yet: Mel Gorman <mgorman@suse.de>
+---
+ mm/page_alloc.c |    3 ++-
+ mm/slub.c       |    3 ++-
+ 2 files changed, 4 insertions(+), 2 deletions(-)
+
+diff --git a/mm/page_alloc.c b/mm/page_alloc.c
+index 9f8a97b..057f1e2 100644
+--- a/mm/page_alloc.c
++++ b/mm/page_alloc.c
+@@ -1972,6 +1972,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
+ {
+ 	int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
+ 	const gfp_t wait = gfp_mask & __GFP_WAIT;
++	const gfp_t can_wake_kswapd = !(gfp_mask & __GFP_NO_KSWAPD);
+ 
+ 	/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
+ 	BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
+@@ -1984,7 +1985,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
+ 	 */
+ 	alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
+ 
+-	if (!wait) {
++	if (!wait && can_wake_kswapd) {
+ 		/*
+ 		 * Not worth trying to allocate harder for
+ 		 * __GFP_NOMEMALLOC even if it can't schedule.
+diff --git a/mm/slub.c b/mm/slub.c
+index 98c358d..1071723 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -1170,7 +1170,8 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+ 	 * Let the initial higher-order allocation fail under memory pressure
+ 	 * so we fall-back to the minimum order allocation.
+ 	 */
+-	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) & ~__GFP_NOFAIL;
++	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) &
++			~(__GFP_NOFAIL | __GFP_WAIT);
+ 
+ 	page = alloc_slab_page(alloc_gfp, node, oo);
+ 	if (unlikely(!page)) {
+-- 
+1.7.3.4
+
+--
+To unsubscribe, send a message with 'unsubscribe linux-mm' in
+the body to majordomo@kvack.org.  For more info on Linux MM,
+see: http://www.linux-mm.org/ .
+Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
+Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
+

mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocations.patch

@@ -0,0 +1,46 @@
+From owner-linux-mm@kvack.org Wed May 11 11:29:50 2011
+From: Mel Gorman <mgorman@suse.de>
+To: Andrew Morton <akpm@linux-foundation.org>
+Subject: [PATCH 1/3] mm: slub: Do not wake kswapd for SLUBs speculative high-order allocations
+Date: Wed, 11 May 2011 16:29:31 +0100
+Message-Id: <1305127773-10570-2-git-send-email-mgorman@suse.de>
+
+To avoid locking and per-cpu overhead, SLUB optimisically uses
+high-order allocations and falls back to lower allocations if they
+fail.  However, by simply trying to allocate, kswapd is woken up to
+start reclaiming at that order. On a desktop system, two users report
+that the system is getting locked up with kswapd using large amounts
+of CPU.  Using SLAB instead of SLUB made this problem go away.
+
+This patch prevents kswapd being woken up for high-order allocations.
+Testing indicated that with this patch applied, the system was much
+harder to hang and even when it did, it eventually recovered.
+
+Signed-off-by: Mel Gorman <mgorman@suse.de>
+---
+ mm/slub.c |    2 +-
+ 1 files changed, 1 insertions(+), 1 deletions(-)
+
+diff --git a/mm/slub.c b/mm/slub.c
+index 9d2e5e4..98c358d 100644
+--- a/mm/slub.c
++++ b/mm/slub.c
+@@ -1170,7 +1170,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+ 	 * Let the initial higher-order allocation fail under memory pressure
+ 	 * so we fall-back to the minimum order allocation.
+ 	 */
+-	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
++	alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) & ~__GFP_NOFAIL;
+ 
+ 	page = alloc_slab_page(alloc_gfp, node, oo);
+ 	if (unlikely(!page)) {
+-- 
+1.7.3.4
+
+--
+To unsubscribe, send a message with 'unsubscribe linux-mm' in
+the body to majordomo@kvack.org.  For more info on Linux MM,
+see: http://www.linux-mm.org/ .
+Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
+Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
+