Re: [PATCH 09/10] mm: only count actual rotations as LRU reclaim cost

[Minchan Kim]

On Mon, Jun 06, 2016 at 03:48:35PM -0400, Johannes Weiner wrote:
> Noting a reference on an active file page but still deactivating it
> represents a smaller cost of reclaim than noting a referenced
> anonymous page and actually physically rotating it back to the head.
> The file page *might* refault later on, but it's definite progress
> toward freeing pages, whereas rotating the anonymous page costs us
> real time without making progress toward the reclaim goal.
> 
> Don't treat both events as equal. The following patch will hook up LRU
> balancing to cache and swap refaults, which are a much more concrete
> cost signal for reclaiming one list over the other. Remove the
> maybe-IO cost bias from page references, and only note the CPU cost
> for actual rotations that prevent the pages from getting reclaimed.
> 
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Acked-by: Minchan Kim <minchan@xxxxxxxxxx>