Add two patches to fix stalls in khugepaged (rhbz 735946)

This commit is contained in:
Josh Boyer 2011-10-17 13:24:14 -04:00
parent 3e1637b657
commit 922059227c
4 changed files with 147 additions and 0 deletions

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@ -0,0 +1,54 @@
From 6b7025ea927d290a59d2772828435c1893f0267f Mon Sep 17 00:00:00 2001
From: Rik van Riel <riel@redhat.com>
Date: Fri, 7 Oct 2011 16:17:22 +0100
Subject: [PATCH 1/2] mm: vmscan: Limit direct reclaim for higher order
allocations
When suffering from memory fragmentation due to unfreeable pages,
THP page faults will repeatedly try to compact memory. Due to the
unfreeable pages, compaction fails.
Needless to say, at that point page reclaim also fails to create
free contiguous 2MB areas. However, that doesn't stop the current
code from trying, over and over again, and freeing a minimum of 4MB
(2UL << sc->order pages) at every single invocation.
This resulted in my 12GB system having 2-3GB free memory, a
corresponding amount of used swap and very sluggish response times.
This can be avoided by having the direct reclaim code not reclaim from
zones that already have plenty of free memory available for compaction.
If compaction still fails due to unmovable memory, doing additional
reclaim will only hurt the system, not help.
Signed-off-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/vmscan.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 6072d74..8c03534 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2022,6 +2022,16 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
continue;
if (zone->all_unreclaimable && priority != DEF_PRIORITY)
continue; /* Let kswapd poll it */
+ if (COMPACTION_BUILD) {
+ /*
+ * If we already have plenty of memory free
+ * for compaction, don't free any more.
+ */
+ if (sc->order > PAGE_ALLOC_COSTLY_ORDER &&
+ (compaction_suitable(zone, sc->order) ||
+ compaction_deferred(zone)))
+ continue;
+ }
/*
* This steals pages from memory cgroups over softlimit
* and returns the number of reclaimed pages and
--
1.7.6.4

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@ -0,0 +1,81 @@
From c01043c9aa51a63bd01c60e53494ca4a7e994542 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman@suse.de>
Date: Fri, 7 Oct 2011 16:17:23 +0100
Subject: [PATCH 2/2] mm: Abort reclaim/compaction if compaction can proceed
If compaction can proceed, shrink_zones() stops doing any work but
the callers still shrink_slab(), raises the priority and potentially
sleeps. This patch aborts direct reclaim/compaction entirely if
compaction can proceed.
Signed-off-by: Mel Gorman <mgorman@suse.de>
---
mm/vmscan.c | 20 ++++++++++++++++----
1 files changed, 16 insertions(+), 4 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 8c03534..b295a38 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -2000,14 +2000,19 @@ restart:
*
* If a zone is deemed to be full of pinned pages then just give it a light
* scan then give up on it.
+ *
+ * This function returns true if a zone is being reclaimed for a costly
+ * high-order allocation and compaction is either ready to begin or deferred.
+ * This indicates to the caller that it should retry the allocation or fail.
*/
-static void shrink_zones(int priority, struct zonelist *zonelist,
+static bool shrink_zones(int priority, struct zonelist *zonelist,
struct scan_control *sc)
{
struct zoneref *z;
struct zone *zone;
unsigned long nr_soft_reclaimed;
unsigned long nr_soft_scanned;
+ bool should_abort_reclaim = false;
for_each_zone_zonelist_nodemask(zone, z, zonelist,
gfp_zone(sc->gfp_mask), sc->nodemask) {
@@ -2025,12 +2030,15 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
if (COMPACTION_BUILD) {
/*
* If we already have plenty of memory free
- * for compaction, don't free any more.
+ * for compaction in this zone , don't free any
+ * more.
*/
if (sc->order > PAGE_ALLOC_COSTLY_ORDER &&
(compaction_suitable(zone, sc->order) ||
- compaction_deferred(zone)))
+ compaction_deferred(zone))) {
+ should_abort_reclaim = true;
continue;
+ }
}
/*
* This steals pages from memory cgroups over softlimit
@@ -2049,6 +2057,8 @@ static void shrink_zones(int priority, struct zonelist *zonelist,
shrink_zone(priority, zone, sc);
}
+
+ return should_abort_reclaim;
}
static bool zone_reclaimable(struct zone *zone)
@@ -2113,7 +2123,9 @@ static unsigned long do_try_to_free_pages(struct zonelist *zonelist,
sc->nr_scanned = 0;
if (!priority)
disable_swap_token(sc->mem_cgroup);
- shrink_zones(priority, zonelist, sc);
+ if (shrink_zones(priority, zonelist, sc))
+ break;
+
/*
* Don't shrink slabs when reclaiming memory from
* over limit cgroups
--
1.7.6.4

1
TODO
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@ -17,6 +17,7 @@
* add-macbookair41-keyboard.patch
* ucvideo-fix-crash-when-linking-entities.patch
* mmc-Always-check-for-lower-base-frequency-quirk-for-.patch (also CC'd stable)
* 000[12]-mm-*
**** Other stuff that should go upstream (in decreasing likelyhood) ************************************

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@ -741,6 +741,10 @@ Patch21001: arm-smsc-support-reading-mac-address-from-device-tree.patch
#rhbz #722509
Patch21002: mmc-Always-check-for-lower-base-frequency-quirk-for-.patch
#rhbz #735946
Patch21020: 0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch
Patch21021: 0002-mm-Abort-reclaim-compaction-if-compaction-can-procee.patch
%endif
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
@ -1358,6 +1362,10 @@ ApplyPatch mmc-Always-check-for-lower-base-frequency-quirk-for-.patch
# utrace.
ApplyPatch utrace.patch
#rhbz #735946
ApplyPatch 0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch
ApplyPatch 0002-mm-Abort-reclaim-compaction-if-compaction-can-procee.patch
# END OF PATCH APPLICATIONS
%endif
@ -2066,6 +2074,9 @@ fi
# ||----w |
# || ||
%changelog
* Mon Oct 17 2011 Josh Boyer <jwboyer@redhat.com>
- Add two patches to fix stalls in khugepaged (rhbz 735946)
* Fri Oct 14 2011 Dave Jones <davej@redhat.com>
- Disable CONFIG_ACPI_PROCFS_POWER which is supposed to be going away soon.