Re: [RHEL-ALT-7.4 PATCH 1/2] numa,sched: slow down scan rate if shared faults dominate

From: Mel Gorman
Date: Wed Aug 02 2017 - 03:01:47 EST


On Mon, Jul 31, 2017 at 03:28:46PM -0400, Rik van Riel wrote:
> From: Rik van Riel <riel@xxxxxxxxxx>
>
> The comment above update_task_scan_period says the scan period should
> be increased (scanning slows down) if the majority of memory accesses
> are on the local node, or if the majority of the page accesses are
> shared with other tasks.
>
> However, with the current code, all a high ratio of shared accesses
> does is slow down the rate at which scanning is made faster.
>
> This patch changes things so either lots of shared accesses or
> lots of local accesses will slow down scanning, and numa scanning
> is sped up only when there are lots of private faults on remote
> memory pages.
>
> Signed-off-by: Rik van Riel <riel@xxxxxxxxxx>

Acked-by: Mel Gorman <mgorman@xxxxxxx>

--
Mel Gorman
SUSE Labs