Re: [PATCH] mm/compaction: clear total_{migrate,free}_scanned before scanning a new zone

Mel Gorman
2019-07-23T07:00:03Z

On Mon, Jul 22, 2019 at 05:17:00PM -0700, Andrew Morton wrote:
> On Mon, 22 Jul 2019 05:54:35 -0400 Yafang Shao <laoar.shao@gmail.com> wrote:
>
> > total_{migrate,free}_scanned will be added to COMPACTMIGRATE_SCANNED and
> > COMPACTFREE_SCANNED in compact_zone(). We should clear them before scanning
> > a new zone.
> > In the proc triggered compaction, we forgot clearing them.
>
> It isn't the worst bug we've ever had, but I'm thinking we should
> backport the fix into -stable kernels?
>

There is no harm in having it in -stable. It may matter for those trying
to debug excessive compaction activity and getting misleading stats.

--
Mel Gorman
SUSE Labs