On Thu, Aug 09, 2012 at 09:11:20AM +0100, Mel Gorman wrote:
> On Thu, Aug 09, 2012 at 10:33:58AM +0900, Minchan Kim wrote:
> > Hi Mel,
> >
> > Just one questoin below.
> >
>
> Sure! Your questions usually get me thinking about the right part of the
> series, this series in particular :)
>
> > > <SNIP>
> > > @@ -708,6 +750,10 @@ static int compact_zone(struct zone *zone, struct compact_control *cc)
> > > goto out;
> > > }
> > > }
> > > +
> > > + /* Capture a page now if it is a suitable size */
> >
> > Why do we capture only when we migrate MIGRATE_MOVABLE type?
> > If you have a reasone, it should have been added as comment.
> >
>
> Good question and there is an answer. However, I also spotted a problem when
> thinking about this more where !MIGRATE_MOVABLE allocations are forced to
> do a full compaction. The simple solution would be to only set cc->page for
> MIGRATE_MOVABLE but there is a better approach that I've implemented in the
> patch below. It includes a comment that should answer your question. Does
> this make sense to you?
It does make sense.
I will add my Reviewed-by in your next spin which includes below patch.
Thanks, Mel.
>
> diff --git a/mm/compaction.c b/mm/compaction.c
> index 63af8d2..384164e 100644
> --- a/mm/compaction.c
> +++ b/mm/compaction.c
> @@ -53,13 +53,31 @@ static inline bool migrate_async_suitable(int migratetype)
> static void compact_capture_page(struct compact_control *cc)
> {
> unsigned long flags;
> - int mtype;
> + int mtype, mtype_low, mtype_high;
>
> if (!cc->page || *cc->page)
> return;
>
> + /*
> + * For MIGRATE_MOVABLE allocations we capture a suitable page ASAP
> + * regardless of the migratetype of the freelist is is captured from.
^ ^
typo?
--
Kind regards,
Minchan Kim
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