pull in some SLUB fixes from Mel Gorman for testing
This commit is contained in:
Kyle McMartin
parent
9b1caead9a
commit
a7e4f1ccd5
11
kernel.spec
11
kernel.spec
@ -711,6 +711,10 @@ Patch12205: runtime_pm_fixups.patch
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Patch12303: dmar-disable-when-ricoh-multifunction.patch
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Patch12400: mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocations.patch
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Patch12401: mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch
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Patch12402: mm-slub-default-slub_max_order-to-0.patch
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%endif
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BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
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@ -1317,6 +1321,10 @@ ApplyPatch acpi_reboot.patch
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# rhbz#605888
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ApplyPatch dmar-disable-when-ricoh-multifunction.patch
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ApplyPatch mm-slub-do-not-wake-kswapd-for-slubs-speculative-high-order-allocations.patch
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ApplyPatch mm-slub-do-not-take-expensive-steps-for-slubs-speculative-high-order-allocations.patch
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ApplyPatch mm-slub-default-slub_max_order-to-0.patch
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# END OF PATCH APPLICATIONS
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%endif
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@ -1925,6 +1933,9 @@ fi
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# and build.
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%changelog
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* Wed May 11 2011 Kyle McMartin <kmcmartin@redhat.com>
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- Pull in some SLUB fixes from Mel Gorman for testing.
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* Tue May 09 2011 Kyle McMartin <kmcmartin@redhat.com> 2.6.39-0.rc7.git0.0
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- Linux 2.6.39-rc7
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67
mm-slub-default-slub_max_order-to-0.patch
Normal file
67
mm-slub-default-slub_max_order-to-0.patch
Normal file
@ -0,0 +1,67 @@
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From owner-linux-mm@kvack.org Wed May 11 11:35:30 2011
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From: Mel Gorman <mgorman@suse.de>
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To: Andrew Morton <akpm@linux-foundation.org>
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Subject: [PATCH 3/3] mm: slub: Default slub_max_order to 0
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Date: Wed, 11 May 2011 16:29:33 +0100
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Message-Id: <1305127773-10570-4-git-send-email-mgorman@suse.de>
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To avoid locking and per-cpu overhead, SLUB optimisically uses
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high-order allocations up to order-3 by default and falls back to
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lower allocations if they fail. While care is taken that the caller
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and kswapd take no unusual steps in response to this, there are
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further consequences like shrinkers who have to free more objects to
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release any memory. There is anecdotal evidence that significant time
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is being spent looping in shrinkers with insufficient progress being
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made (https://lkml.org/lkml/2011/4/28/361) and keeping kswapd awake.
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SLUB is now the default allocator and some bug reports have been
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pinned down to SLUB using high orders during operations like
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copying large amounts of data. SLUBs use of high-orders benefits
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applications that are sized to memory appropriately but this does not
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necessarily apply to large file servers or desktops. This patch
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causes SLUB to use order-0 pages like SLAB does by default.
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There is further evidence that this keeps kswapd's usage lower
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(https://lkml.org/lkml/2011/5/10/383).
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Signed-off-by: Mel Gorman <mgorman@suse.de>
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---
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Documentation/vm/slub.txt | 2 +-
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mm/slub.c | 2 +-
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2 files changed, 2 insertions(+), 2 deletions(-)
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diff --git a/Documentation/vm/slub.txt b/Documentation/vm/slub.txt
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index 07375e7..778e9fa 100644
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--- a/Documentation/vm/slub.txt
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+++ b/Documentation/vm/slub.txt
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@@ -117,7 +117,7 @@ can be influenced by kernel parameters:
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slub_min_objects=x (default 4)
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slub_min_order=x (default 0)
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-slub_max_order=x (default 1)
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+slub_max_order=x (default 0)
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slub_min_objects allows to specify how many objects must at least fit
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into one slab in order for the allocation order to be acceptable.
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diff --git a/mm/slub.c b/mm/slub.c
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index 1071723..23a4789 100644
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--- a/mm/slub.c
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+++ b/mm/slub.c
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@@ -2198,7 +2198,7 @@ EXPORT_SYMBOL(kmem_cache_free);
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* take the list_lock.
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*/
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static int slub_min_order;
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-static int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
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+static int slub_max_order;
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static int slub_min_objects;
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/*
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--
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1.7.3.4
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--
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To unsubscribe, send a message with 'unsubscribe linux-mm' in
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the body to majordomo@kvack.org. For more info on Linux MM,
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see: http://www.linux-mm.org/ .
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Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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@ -0,0 +1,73 @@
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From owner-linux-mm@kvack.org Wed May 11 11:29:53 2011
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From: Mel Gorman <mgorman@suse.de>
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To: Andrew Morton <akpm@linux-foundation.org>
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Subject: [PATCH 2/3] mm: slub: Do not take expensive steps for SLUBs speculative high-order allocations
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Date: Wed, 11 May 2011 16:29:32 +0100
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Message-Id: <1305127773-10570-3-git-send-email-mgorman@suse.de>
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To avoid locking and per-cpu overhead, SLUB optimisically uses
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high-order allocations and falls back to lower allocations if they
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fail. However, by simply trying to allocate, the caller can enter
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compaction or reclaim - both of which are likely to cost more than the
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benefit of using high-order pages in SLUB. On a desktop system, two
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users report that the system is getting stalled with kswapd using large
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amounts of CPU.
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This patch prevents SLUB taking any expensive steps when trying to
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use high-order allocations. Instead, it is expected to fall back to
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smaller orders more aggressively. Testing from users was somewhat
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inconclusive on how much this helped but local tests showed it made
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a positive difference. It makes sense that falling back to order-0
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allocations is faster than entering compaction or direct reclaim.
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Signed-off-yet: Mel Gorman <mgorman@suse.de>
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---
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mm/page_alloc.c | 3 ++-
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mm/slub.c | 3 ++-
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2 files changed, 4 insertions(+), 2 deletions(-)
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diff --git a/mm/page_alloc.c b/mm/page_alloc.c
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index 9f8a97b..057f1e2 100644
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--- a/mm/page_alloc.c
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+++ b/mm/page_alloc.c
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@@ -1972,6 +1972,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
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{
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int alloc_flags = ALLOC_WMARK_MIN | ALLOC_CPUSET;
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const gfp_t wait = gfp_mask & __GFP_WAIT;
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+ const gfp_t can_wake_kswapd = !(gfp_mask & __GFP_NO_KSWAPD);
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/* __GFP_HIGH is assumed to be the same as ALLOC_HIGH to save a branch. */
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BUILD_BUG_ON(__GFP_HIGH != (__force gfp_t) ALLOC_HIGH);
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@@ -1984,7 +1985,7 @@ gfp_to_alloc_flags(gfp_t gfp_mask)
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*/
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alloc_flags |= (__force int) (gfp_mask & __GFP_HIGH);
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- if (!wait) {
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+ if (!wait && can_wake_kswapd) {
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/*
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* Not worth trying to allocate harder for
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* __GFP_NOMEMALLOC even if it can't schedule.
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diff --git a/mm/slub.c b/mm/slub.c
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index 98c358d..1071723 100644
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--- a/mm/slub.c
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+++ b/mm/slub.c
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@@ -1170,7 +1170,8 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
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* Let the initial higher-order allocation fail under memory pressure
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* so we fall-back to the minimum order allocation.
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*/
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- alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) & ~__GFP_NOFAIL;
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+ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) &
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+ ~(__GFP_NOFAIL | __GFP_WAIT);
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page = alloc_slab_page(alloc_gfp, node, oo);
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if (unlikely(!page)) {
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--
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1.7.3.4
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--
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To unsubscribe, send a message with 'unsubscribe linux-mm' in
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the body to majordomo@kvack.org. For more info on Linux MM,
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||||
see: http://www.linux-mm.org/ .
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Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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@ -0,0 +1,46 @@
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From owner-linux-mm@kvack.org Wed May 11 11:29:50 2011
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From: Mel Gorman <mgorman@suse.de>
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To: Andrew Morton <akpm@linux-foundation.org>
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Subject: [PATCH 1/3] mm: slub: Do not wake kswapd for SLUBs speculative high-order allocations
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Date: Wed, 11 May 2011 16:29:31 +0100
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Message-Id: <1305127773-10570-2-git-send-email-mgorman@suse.de>
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To avoid locking and per-cpu overhead, SLUB optimisically uses
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high-order allocations and falls back to lower allocations if they
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fail. However, by simply trying to allocate, kswapd is woken up to
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start reclaiming at that order. On a desktop system, two users report
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that the system is getting locked up with kswapd using large amounts
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of CPU. Using SLAB instead of SLUB made this problem go away.
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This patch prevents kswapd being woken up for high-order allocations.
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Testing indicated that with this patch applied, the system was much
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harder to hang and even when it did, it eventually recovered.
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Signed-off-by: Mel Gorman <mgorman@suse.de>
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---
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mm/slub.c | 2 +-
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1 files changed, 1 insertions(+), 1 deletions(-)
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diff --git a/mm/slub.c b/mm/slub.c
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index 9d2e5e4..98c358d 100644
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--- a/mm/slub.c
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+++ b/mm/slub.c
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@@ -1170,7 +1170,7 @@ static struct page *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
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* Let the initial higher-order allocation fail under memory pressure
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* so we fall-back to the minimum order allocation.
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*/
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- alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
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+ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY | __GFP_NO_KSWAPD) & ~__GFP_NOFAIL;
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page = alloc_slab_page(alloc_gfp, node, oo);
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if (unlikely(!page)) {
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--
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1.7.3.4
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--
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||||
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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||||
the body to majordomo@kvack.org. For more info on Linux MM,
|
||||
see: http://www.linux-mm.org/ .
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||||
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
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Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
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