The patch titled
Subject: vmscan: limit direct reclaim for higher order allocations
has been added to the -mm tree. Its filename is
vmscan-limit-direct-reclaim-for-higher-order-allocations.patch
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------------------------------------------------------
From: Rik van Riel <riel@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Acked-by: Johannes Weiner <jweiner@xxxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxx>
---
mm/vmscan.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff -puN mm/vmscan.c~vmscan-limit-direct-reclaim-for-higher-order-allocations mm/vmscan.c
--- a/mm/vmscan.c~vmscan-limit-direct-reclaim-for-higher-order-allocations
+++ a/mm/vmscan.c
@@ -2108,6 +2108,16 @@ static void shrink_zones(int priority, s
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
_
Subject: Subject: vmscan: limit direct reclaim for higher order allocations
Patches currently in -mm which might be from riel@xxxxxxxxxx are
linux-next.patch
mm-compaction-trivial-clean-up-in-acct_isolated.patch
mm-change-isolate-mode-from-define-to-bitwise-type.patch
mm-change-isolate-mode-from-define-to-bitwise-type-fix.patch
mm-compaction-make-isolate_lru_page-filter-aware.patch
mm-compaction-make-isolate_lru_page-filter-aware-fix.patch
mm-zone_reclaim-make-isolate_lru_page-filter-aware.patch
mm-zone_reclaim-make-isolate_lru_page-filter-aware-fix.patch
mm-migration-clean-up-unmap_and_move.patch
mm-vmscan-do-not-writeback-filesystem-pages-in-direct-reclaim.patch
mm-vmscan-remove-dead-code-related-to-lumpy-reclaim-waiting-on-pages-under-writeback.patch
xfs-warn-if-direct-reclaim-tries-to-writeback-pages.patch
ext4-warn-if-direct-reclaim-tries-to-writeback-pages.patch
mm-vmscan-do-not-writeback-filesystem-pages-in-kswapd-except-in-high-priority.patch
mm-vmscan-throttle-reclaim-if-encountering-too-many-dirty-pages-under-writeback.patch
mm-vmscan-immediately-reclaim-end-of-lru-dirty-pages-when-writeback-completes.patch
vmscan-promote-shared-file-mapped-pages.patch
vmscan-activate-executable-pages-after-first-usage.patch
mremap-check-for-overflow-using-deltas.patch
mremap-avoid-sending-one-ipi-per-page.patch
thp-mremap-support-and-tlb-optimization.patch
thp-mremap-support-and-tlb-optimization-fix.patch
thp-mremap-support-and-tlb-optimization-fix-fix.patch
kswapd-avoid-unnecessary-rebalance-after-an-unsuccessful-balancing.patch
mm-compaction-compact-unevictable-pages.patch
mm-compaction-accounting-fix.patch
mm-fix-page-faults-detection-in-swap-token-logic.patch
mm-add-extra-free-kbytes-tunable.patch
mm-add-extra-free-kbytes-tunable-update.patch
mm-add-extra-free-kbytes-tunable-update-checkpatch-fixes.patch
mm-thrashc-quiet-sparse-noise.patch
mm-huge_memoryc-quiet-sparse-noise.patch
vmscan-add-barrier-to-prevent-evictable-page-in-unevictable-list.patch
vmscan-limit-direct-reclaim-for-higher-order-allocations.patch
memcg-skip-scanning-active-lists-based-on-individual-size.patch
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