Re: [PATCH v2 2/3] mm: remain migratetype in freed page

From: Minchan Kim
Date: Thu Sep 06 2012 - 20:06:42 EST


On Thu, Sep 06, 2012 at 03:13:08PM +0900, Kamezawa Hiroyuki wrote:
> (2012/09/06 14:16), Minchan Kim wrote:
> > The page allocator caches the pageblock information in page->private while
> > it is in the PCP freelists but this is overwritten with the order of the
> > page when freed to the buddy allocator. This patch stores the migratetype
> > of the page in the page->index field so that it is available at all times
> > when the page remain in free_list.
> >
> sounds reasonable.
>
> > This patch adds a new call site in __free_pages_ok so it might be
> > overhead a bit but it's for high order allocation.
> > So I believe damage isn't hurt.
> >
> > * from v1
> > * Fix move_freepages's migratetype - Mel
> > * Add more kind explanation in description - Mel
> >
> > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
>
> Hmm, page->index is valid only when the page is the head of buddy chunk ?

Yes.

>
> Anyway,
>
> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

Thanks, Kame!

--
Kind regards,
Minchan Kim
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