Re: [PATCH 3/5] mm, pagevec: Release/reacquire lru_lock on pgdat change

From	Johannes Weiner <hannes@cmpxchg.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/5] mm, pagevec: Release/reacquire lru_lock on pgdat change
Date	2016-07-18 18:30 +0200
Message-ID	<rWjAB-7K-3@gated-at.bofh.it> (permalink)
References	<rVb2q-7js-21@gated-at.bofh.it> <rVb2r-7js-33@gated-at.bofh.it>
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On Fri, Jul 15, 2016 at 02:09:23PM +0100, Mel Gorman wrote:
> With node-lru, the locking is based on the pgdat. Previously it was
> required that a pagevec drain released one zone lru_lock and acquired
> another zone lru_lock on every zone change. Now, it's only necessary if
> the node changes. The end-result is fewer lock release/acquires if the
> pages are all on the same node but in different zones.
> 
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>

This could make quite a difference on some workloads, from a whole
series perspective, when considering that we had the round robin fair
zone allocator on top of this. Page batches that span multiple nodes
on the other hand are much less likely.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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[PATCH 3/5] mm, pagevec: Release/reacquire lru_lock on pgdat change Mel Gorman <mgorman@techsingularity.net> - 2016-07-15 15:10 +0200
  Re: [PATCH 3/5] mm, pagevec: Release/reacquire lru_lock on pgdat  change Minchan Kim <minchan@kernel.org> - 2016-07-15 18:00 +0200
  Re: [PATCH 3/5] mm, pagevec: Release/reacquire lru_lock on pgdat  change Johannes Weiner <hannes@cmpxchg.org> - 2016-07-18 18:30 +0200

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