From: Mel Gorman <mgorman@suse.de> To: Stable <stable@vger.kernel.org> Cc: Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de> Subject: [PATCH 30/34] mm: vmscan: Do not force kswapd to scan small targets Date: Mon, 23 Jul 2012 14:38:43 +0100 [thread overview] Message-ID: <1343050727-3045-31-git-send-email-mgorman@suse.de> (raw) In-Reply-To: <1343050727-3045-1-git-send-email-mgorman@suse.de> commit ad2b8e601099a23dffffb53f91c18d874fe98854 upstream - WARNING: this is a substitute patch. Stable note: Not tracked in Bugzilla. This is a substitute for an upstream commit addressing a completely different issue that accidentally contained an important fix. The workload this patch helps was memcached when IO is started in the background. memcached should stay resident but without this patch it gets swapped more than it should. Sometimes this manifests as a drop in throughput but mostly it was observed through /proc/vmstat. Commit [246e87a9: memcg: fix get_scan_count() for small targets] was meant to fix a problem whereby small scan targets on memcg were ignored causing priority to raise too sharply. It forced scanning to take place if the target was small, memcg or kswapd. >From the time it was introduced it cause excessive reclaim by kswapd with workloads being pushed to swap that previously would have stayed resident. This was accidentally fixed by commit [ad2b8e60: mm: memcg: remove optimization of keeping the root_mem_cgroup LRU lists empty] but that patchset is not suitable for backporting. The original patch came with no information on what workloads it benefits but the cost of it is obvious in that it forces scanning to take place on lists that would otherwise have been ignored such as small anonymous inactive lists. This patch partially reverts 246e87a9 so that small lists are not force scanned which means that IO-intensive workloads with small amounts of anonymous memory will not be swapped. Signed-off-by: Mel Gorman <mgorman@suse.de> --- mm/vmscan.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index e5382ad..49d8547 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1849,9 +1849,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc, bool force_scan = false; unsigned long nr_force_scan[2]; - /* kswapd does zone balancing and needs to scan this zone */ - if (scanning_global_lru(sc) && current_is_kswapd()) - force_scan = true; /* memcg may have small limit and need to avoid priority drop */ if (!scanning_global_lru(sc)) force_scan = true; -- 1.7.9.2
WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de> To: Stable <stable@vger.kernel.org> Cc: Linux-MM <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>, Mel Gorman <mgorman@suse.de> Subject: [PATCH 30/34] mm: vmscan: Do not force kswapd to scan small targets Date: Mon, 23 Jul 2012 14:38:43 +0100 [thread overview] Message-ID: <1343050727-3045-31-git-send-email-mgorman@suse.de> (raw) In-Reply-To: <1343050727-3045-1-git-send-email-mgorman@suse.de> commit ad2b8e601099a23dffffb53f91c18d874fe98854 upstream - WARNING: this is a substitute patch. Stable note: Not tracked in Bugzilla. This is a substitute for an upstream commit addressing a completely different issue that accidentally contained an important fix. The workload this patch helps was memcached when IO is started in the background. memcached should stay resident but without this patch it gets swapped more than it should. Sometimes this manifests as a drop in throughput but mostly it was observed through /proc/vmstat. Commit [246e87a9: memcg: fix get_scan_count() for small targets] was meant to fix a problem whereby small scan targets on memcg were ignored causing priority to raise too sharply. It forced scanning to take place if the target was small, memcg or kswapd. >From the time it was introduced it cause excessive reclaim by kswapd with workloads being pushed to swap that previously would have stayed resident. This was accidentally fixed by commit [ad2b8e60: mm: memcg: remove optimization of keeping the root_mem_cgroup LRU lists empty] but that patchset is not suitable for backporting. The original patch came with no information on what workloads it benefits but the cost of it is obvious in that it forces scanning to take place on lists that would otherwise have been ignored such as small anonymous inactive lists. This patch partially reverts 246e87a9 so that small lists are not force scanned which means that IO-intensive workloads with small amounts of anonymous memory will not be swapped. Signed-off-by: Mel Gorman <mgorman@suse.de> --- mm/vmscan.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/vmscan.c b/mm/vmscan.c index e5382ad..49d8547 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -1849,9 +1849,6 @@ static void get_scan_count(struct zone *zone, struct scan_control *sc, bool force_scan = false; unsigned long nr_force_scan[2]; - /* kswapd does zone balancing and needs to scan this zone */ - if (scanning_global_lru(sc) && current_is_kswapd()) - force_scan = true; /* memcg may have small limit and need to avoid priority drop */ if (!scanning_global_lru(sc)) force_scan = true; -- 1.7.9.2 -- 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/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2012-07-23 13:40 UTC|newest] Thread overview: 121+ messages / expand[flat|nested] mbox.gz Atom feed top 2012-07-23 13:38 [PATCH 00/34] Memory management performance backports for -stable V2 Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 01/34] mm: vmstat: cache align vm_stat Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 02/34] mm: memory hotplug: Check if pages are correctly reserved on a per-section basis Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 03/34] mm: Reduce the amount of work done when updating min_free_kbytes Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-24 22:47 ` Greg KH 2012-07-24 22:47 ` Greg KH 2012-07-25 7:57 ` Mel Gorman 2012-07-25 7:57 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 04/34] mm: vmscan: fix force-scanning small targets without swap Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 05/34] vmscan: clear ZONE_CONGESTED for zone with good watermark Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 06/34] vmscan: add shrink_slab tracepoints Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 07/34] vmscan: shrinker->nr updates race and go wrong Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 08/34] vmscan: reduce wind up shrinker->nr when shrinker can't do work Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 09/34] mm: limit direct reclaim for higher order allocations Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 10/34] mm: Abort reclaim/compaction if compaction can proceed Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 11/34] mm: compaction: trivial clean up in acct_isolated() Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 12/34] mm: change isolate mode from #define to bitwise type Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 13/34] mm: compaction: make isolate_lru_page() filter-aware Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 14/34] mm: zone_reclaim: " Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 15/34] mm: migration: clean up unmap_and_move() Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-25 15:45 ` Greg KH 2012-07-25 15:45 ` Greg KH 2012-07-25 16:04 ` Mel Gorman 2012-07-25 16:04 ` Mel Gorman 2012-07-25 18:03 ` Greg KH 2012-07-25 18:03 ` Greg KH 2012-07-23 13:38 ` [PATCH 16/34] mm: compaction: Allow compaction to isolate dirty pages Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-25 15:47 ` Greg KH 2012-07-25 15:47 ` Greg KH 2012-07-25 16:07 ` Mel Gorman 2012-07-25 16:07 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 17/34] mm: compaction: Determine if dirty pages can be migrated without blocking within ->migratepage Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 18/34] mm: page allocator: Do not call direct reclaim for THP allocations while compaction is deferred Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 19/34] mm: compaction: make isolate_lru_page() filter-aware again Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 20/34] kswapd: avoid unnecessary rebalance after an unsuccessful balancing Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 21/34] kswapd: assign new_order and new_classzone_idx after wakeup in sleeping Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 22/34] mm: compaction: Introduce sync-light migration for use by compaction Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 23/34] mm: vmscan: When reclaiming for compaction, ensure there are sufficient free pages available Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 24/34] mm: vmscan: Do not OOM if aborting reclaim to start compaction Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 25/34] mm: vmscan: Check if reclaim should really abort even if compaction_ready() is true for one zone Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-25 19:51 ` Greg KH 2012-07-25 19:51 ` Greg KH 2012-07-23 13:38 ` [PATCH 26/34] vmscan: promote shared file mapped pages Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 27/34] vmscan: activate executable pages after first usage Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 28/34] mm/vmscan.c: consider swap space when deciding whether to continue reclaim Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 29/34] mm: test PageSwapBacked in lumpy reclaim Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` Mel Gorman [this message] 2012-07-23 13:38 ` [PATCH 30/34] mm: vmscan: Do not force kswapd to scan small targets Mel Gorman 2012-07-25 19:59 ` Greg KH 2012-07-25 19:59 ` Greg KH 2012-07-25 21:35 ` Mel Gorman 2012-07-25 21:35 ` Mel Gorman 2012-07-25 21:44 ` Greg KH 2012-07-25 21:44 ` Greg KH 2012-07-23 13:38 ` [PATCH 31/34] cpusets: avoid looping when storing to mems_allowed if one node remains set Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 32/34] cpusets: stall when updating mems_allowed for mempolicy or disjoint nodemask Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 33/34] cpuset: mm: Reduce large amounts of memory barrier related damage v3 Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-23 13:38 ` [PATCH 34/34] mm/hugetlb: fix warning in alloc_huge_page/dequeue_huge_page_vma Mel Gorman 2012-07-23 13:38 ` Mel Gorman 2012-07-24 5:58 ` [PATCH 00/34] Memory management performance backports for -stable V2 Mike Galbraith 2012-07-24 5:58 ` Mike Galbraith 2012-07-24 8:10 ` Mel Gorman 2012-07-24 8:10 ` Mel Gorman 2012-07-24 13:18 ` Hillf Danton 2012-07-24 13:18 ` Hillf Danton 2012-07-24 13:27 ` Mel Gorman 2012-07-24 13:27 ` Mel Gorman 2012-07-24 13:34 ` Hillf Danton 2012-07-24 13:34 ` Hillf Danton 2012-07-24 13:53 ` Mel Gorman 2012-07-24 13:53 ` Mel Gorman 2012-07-24 14:11 ` Hillf Danton 2012-07-24 14:11 ` Hillf Danton 2012-07-24 13:52 ` Mike Galbraith 2012-07-24 13:52 ` Mike Galbraith 2012-07-24 14:18 ` Hillf Danton 2012-07-24 14:18 ` Hillf Danton 2012-07-24 14:41 ` Mike Galbraith 2012-07-24 14:41 ` Mike Galbraith 2012-07-25 22:30 ` Greg KH 2012-07-25 22:30 ` Greg KH 2012-07-25 22:48 ` Mel Gorman 2012-07-25 22:48 ` Mel Gorman 2012-07-30 1:13 ` Ben Hutchings -- strict thread matches above, loose matches on Subject: below -- 2012-07-19 14:36 [PATCH 00/34] Memory management performance backports for -stable Mel Gorman 2012-07-19 14:36 ` [PATCH 30/34] mm: vmscan: Do not force kswapd to scan small targets Mel Gorman 2012-07-19 14:36 ` Mel Gorman 2012-07-19 20:37 ` Jonathan Nieder 2012-07-19 22:08 ` Mel Gorman
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