Re: [PATCH 21/34] mm, vmscan: only wakeup kswapd once per node for the requested classzone

[Johannes Weiner]

On Fri, Jul 08, 2016 at 10:34:57AM +0100, Mel Gorman wrote:
> kswapd is woken when zones are below the low watermark but the wakeup
> decision is not taking the classzone into account.  Now that reclaim is
> node-based, it is only required to wake kswapd once per node and only if
> all zones are unbalanced for the requested classzone.
> 
> Note that one node might be checked multiple times if the zonelist is
> ordered by node because there is no cheap way of tracking what nodes have
> already been visited.  For zone-ordering, each node should be checked only
> once.
> 
> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>

Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>