Re: [PATCH 1/7] mm: compaction: Allow compaction to isolate dirtypages

From: Minchan Kim
Date: Tue Nov 22 2011 - 11:58:39 EST


On Mon, Nov 21, 2011 at 06:36:42PM +0000, Mel Gorman wrote:
> Commit [39deaf85: mm: compaction: make isolate_lru_page() filter-aware]
> noted that compaction does not migrate dirty or writeback pages and
> that is was meaningless to pick the page and re-add it to the LRU list.
>
> What was missed during review is that asynchronous migration moves
> dirty pages if their ->migratepage callback is migrate_page() because
> these can be moved without blocking. This potentially impacted
> hugepage allocation success rates by a factor depending on how many
> dirty pages are in the system.
>
> This patch partially reverts 39deaf85 to allow migration to isolate
> dirty pages again. This increases how much compaction disrupts the
> LRU but that is addressed later in the series.
>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
> Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
> Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>

Mel, Thanks for the fix.

--
Kind regards,
Minchan Kim
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