Messages in this thread | | | Date | Thu, 25 Feb 2016 17:17:46 -0500 | From | Johannes Weiner <> | Subject | Re: [PATCH 07/27] mm, vmscan: Have kswapd only scan based on the highest requested zone |
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On Tue, Feb 23, 2016 at 03:04:30PM +0000, Mel Gorman wrote: > kswapd checks all eligible zones to see if they need balancing even if it was > woken for a lower zone. This made sense when we reclaimed on a per-zone basis > because we wanted to shrink zones fairly so avoid age-inversion problems. > Ideally this is completely unnecessary when reclaiming on a per-node basis. > In theory, there may still be anomalies when all requests are for lower > zones and very old pages are preserved in higher zones but this should be > the exceptional case. > > Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
As I mentioned in the other subthread, this should probably be fine, although it would be good, generally, to have some sort of statistics on how much of the age-distorting reclaim is happening, and then maybe mention its existence in the changelog of this patch. Just an idea.
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