Re: [PATCH 03/10] mm, page_alloc: Remove unnecessary recalculations for dirty zone balancing

From: Michal Hocko
Date: Thu Aug 20 2015 - 10:25:35 EST


On Thu 20-08-15 14:45:26, Mel Gorman wrote:
> On Thu, Aug 20, 2015 at 02:45:27PM +0200, Michal Hocko wrote:
> > On Wed 12-08-15 11:45:28, Mel Gorman wrote:
> > > File-backed pages that will be immediately are balanced between zones but
> > ^written to...
> >
> > > it's unnecessarily expensive.
> >
> > to do WHAT? I guess you meant checking gfp_mask resp. alloc_mask? I
> > doubt it would make a noticeable difference as this is a slow path
> > already but I agree it doesn't make sense to check it again.
> >
>
> File-backed pages that will be immediately written are balanced between
> zones. This heuristic tries to avoid having a single zone filled with
> recently dirtied pages but the checks are unnecessarily expensive. Move
> consider_zone_balanced into the alloc_context instead of checking bitmaps
> multiple times. The patch also gives the parameter a more meaningful name.

Sounds much better. Thanks!
--
Michal Hocko
SUSE Labs
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