diff options
Diffstat (limited to '0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch')
| -rw-r--r-- | 0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch b/0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch new file mode 100644 index 000000000..77777f012 --- /dev/null +++ b/0001-mm-vmscan-Limit-direct-reclaim-for-higher-order-allo.patch @@ -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 + |