Re: [PATCH] mm: vmscan: check mem cgroup over reclaimed
From: Ying Han <hidden>
Date: 2012-01-23 19:04:09
Also in:
lkml
On Sun, Jan 22, 2012 at 5:55 PM, Hillf Danton [off-list ref] wrote:
quoted hunk ↗ jump to hunk
To avoid reduction in performance of reclaimee, checking overreclaim is added after shrinking lru list, when pages are reclaimed from mem cgroup. If over reclaim occurs, shrinking remaining lru lists is skipped, and no more reclaim for reclaim/compaction. Signed-off-by: Hillf Danton <redacted> ------ a/mm/vmscan.c Mon Jan 23 00:23:10 2012 +++ b/mm/vmscan.c Mon Jan 23 09:57:20 2012@@ -2086,6 +2086,7 @@ static void shrink_mem_cgroup_zone(int punsigned long nr_reclaimed, nr_scanned; unsigned long nr_to_reclaim = sc->nr_to_reclaim; struct blk_plug plug; + bool memcg_over_reclaimed = false; restart: nr_reclaimed = 0;@@ -2103,6 +2104,11 @@ restart:nr_reclaimed += shrink_list(lru, nr_to_scan, mz, sc, priority); + + memcg_over_reclaimed = !scanning_global_lru(mz) + && (nr_reclaimed >= nr_to_reclaim); + if (memcg_over_reclaimed) + goto out;
Why we need the change here? Do we have number to demonstrate?
quoted hunk ↗ jump to hunk
} } /*@@ -2116,6 +2122,7 @@ restart:if (nr_reclaimed >= nr_to_reclaim && priority < DEF_PRIORITY) break; } +out: blk_finish_plug(&plug); sc->nr_reclaimed += nr_reclaimed;@@ -2127,7 +2134,8 @@ restart:shrink_active_list(SWAP_CLUSTER_MAX, mz, sc, priority, 0); /* reclaim/compaction might need reclaim to continue */ - if (should_continue_reclaim(mz, nr_reclaimed, + if (!memcg_over_reclaimed && + should_continue_reclaim(mz, nr_reclaimed, sc->nr_scanned - nr_scanned, sc))
This changes the existing logic. What if the nr_reclaimed is greater than nr_to_reclaim, but smaller than pages_for_compaction? The existing logic is to continue reclaiming. --Ying
goto restart;
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