Re: [PATCH 06/27] mm, vmscan: Make kswapd reclaim in terms of nodes

Vlastimil Babka
2016-06-15T14:23:16Z

On 06/09/2016 08:04 PM, Mel Gorman wrote:
> Patch "mm: vmscan: Begin reclaiming pages on a per-node basis" started
> thinking of reclaim in terms of nodes but kswapd is still zone-centric. This
> patch gets rid of many of the node-based versus zone-based decisions.
>
> o A node is considered balanced when any eligible lower zone is balanced.
> This eliminates one class of age-inversion problem because we avoid
> reclaiming a newer page just because it's in the wrong zone
> o pgdat_balanced disappears because we now only care about one zone being
> balanced.
> o Some anomalies related to writeback and congestion tracking being based on
> zones disappear.
> o kswapd no longer has to take care to reclaim zones in the reverse order
> that the page allocator uses.
> o Most importantly of all, reclaim from node 0 with multiple zones will
> have similar aging and reclaiming characteristics as every
> other node.
>
> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

Acked-by: Vlastimil Babka <vbabka@suse.cz>