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 <[email protected]>
Acked-by: Johannes Weiner <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
