Re: [PATCH v2 9/9] mm/compaction: new threshold for compaction depleted zone

Joonsoo Kim
2015-10-15T06:05:46Z

On Wed, Oct 14, 2015 at 02:28:31PM +0200, Vlastimil Babka wrote:
> On 08/24/2015 04:19 AM, Joonsoo Kim wrote:
> > Now, compaction algorithm become powerful. Migration scanner traverses
> > whole zone range. So, old threshold for depleted zone which is designed
> > to imitate compaction deferring approach isn't appropriate for current
> > compaction algorithm. If we adhere to current threshold, 1, we can't
> > avoid excessive overhead caused by compaction, because one compaction
> > for low order allocation would be easily successful in any situation.
> >
> > This patch re-implements threshold calculation based on zone size and
> > allocation requested order. We judge whther compaction possibility is
> > depleted or not by number of successful compaction. Roughly, 1/100
> > of future scanned area should be allocated for high order page during
> > one comaction iteration in order to determine whether zone's compaction
> > possiblity is depleted or not.
>
> Finally finishing my review, sorry it took that long...
>

Ah... I forgot to mention that I really appreciate your help.
Thanks for review!!

Thanks!