Commit 7c5bd705 authored Feb 22, 2013 by Johannes Weiner Committed by Linus Torvalds Feb 23, 2013

mm: memcg: only evict file pages when we have plenty



Commit e9868505 ("mm, vmscan: only evict file pages when we have
plenty") makes a point of not going for anonymous memory while there is
still enough inactive cache around.

The check was added only for global reclaim, but it is just as useful to
reduce swapping in memory cgroup reclaim:

    200M-memcg-defconfig-j2

                                     vanilla                   patched
    Real time              454.06 (  +0.00%)         453.71 (  -0.08%)
    User time              668.57 (  +0.00%)         668.73 (  +0.02%)
    System time            128.92 (  +0.00%)         129.53 (  +0.46%)
    Swap in               1246.80 (  +0.00%)         814.40 ( -34.65%)
    Swap out              1198.90 (  +0.00%)         827.00 ( -30.99%)
    Pages allocated   16431288.10 (  +0.00%)    16434035.30 (  +0.02%)
    Major faults           681.50 (  +0.00%)         593.70 ( -12.86%)
    THP faults             237.20 (  +0.00%)         242.40 (  +2.18%)
    THP collapse           241.20 (  +0.00%)         248.50 (  +3.01%)
    THP splits             157.30 (  +0.00%)         161.40 (  +2.59%)

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Satoru Moriya <satoru.moriya@hds.com>
Cc: Simon Jeons <simon.jeons@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 2a6f5124

mm/vmscan.c

+11 −9

Original line number	Diff line number	Diff line
		@@ -1700,17 +1700,19 @@ static void get_scan_count(struct lruvec lruvec, struct scan_control sc,
		fraction[1] = 0;
		denominator = 1;
		goto out;
		} else if (!inactive_file_is_low_global(zone)) {
		}
		}

		/*
		* There is enough inactive page cache, do not
		* reclaim anything from the working set right now.
		* There is enough inactive page cache, do not reclaim
		* anything from the anonymous working set right now.
		*/
		if (!inactive_file_is_low(lruvec)) {
		fraction[0] = 0;
		fraction[1] = 1;
		denominator = 1;
		goto out;
		}
		}

		/*
		* With swappiness at 100, anonymous and file have the same priority.

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