Re: [PATCH 2/4] mm/page_alloc: expands broken freepage to proper buddy list when steal

[Vlastimil Babka]

On 12/10/2014 07:38 AM, Joonsoo Kim wrote:
> On Mon, Dec 08, 2014 at 10:29:44AM +0100, Vlastimil Babka wrote:
> > On 12/08/2014 08:16 AM, Joonsoo Kim wrote:
> > > There is odd behaviour when we steal freepages from other migratetype
> > > buddy list. In try_to_steal_freepages(), we move all freepages in
> > > the pageblock that founded freepage is belong to to the request
> > > migratetype in order to mitigate fragmentation. If the number of moved
> > > pages are enough to change pageblock migratetype, there is no problem. If
> > > not enough, we don't change pageblock migratetype and add broken freepages
> > > to the original migratetype buddy list rather than request migratetype
> > > one. For me, this is odd, because we already moved all freepages in this
> > > pageblock to the request migratetype. This patch fixes this situation to
> > > add broken freepages to the request migratetype buddy list in this case.
> >
> > I'd rather split the fix from the refactoring. And maybe my
> > description is longer, but easier to understand? (I guess somebody
> > else should judge this)
>
> Your patch is much better to understand than mine. :)
> No need to judge from somebody else.
> After your patch is merged, I will resubmit these on top of it.

Thanks. I'm doing another evaluation focusing on number of unmovable 
pageblocks as Mel suggested and then resubmit with tracepoint fixed.

Vlastimil
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