Re: [PATCH v2 2/2] compaction: fix COMPACTPAGEFAILED counting

[Mel Gorman]

On Wed, Aug 25, 2010 at 12:43:40AM +0900, Minchan Kim wrote:
> Now update_nr_listpages doesn't have a role. That's because
> lists passed is always empty just after calling migrate_pages.
> The migrate_pages cleans up page list which have failed to migrate
> before returning by aaa994b3.
> 
>  [PATCH] page migration: handle freeing of pages in migrate_pages()
> 
>  Do not leave pages on the lists passed to migrate_pages().  Seems that we will
>  not need any postprocessing of pages.  This will simplify the handling of
>  pages by the callers of migrate_pages().
> 
> At that time, we thought we don't need any postprocessing of pages.
> But the situation is changed. The compaction need to know the number of
> failed to migrate for COMPACTPAGEFAILED stat
> 
> This patch makes new rule for caller of migrate_pages to call putback_lru_pages.
> So caller need to clean up the lists so it has a chance to postprocess the pages.
> [suggested by Christoph Lameter]
> 
> Cc: Hugh Dickins <hughd@xxxxxxxxxx>
> Cc: Andi Kleen <andi@xxxxxxxxxxxxxx>
> Cc: Christoph Lameter <cl@xxxxxxxxx>
> Cc: Mel Gorman <mel@xxxxxxxxx>
> Signed-off-by: Minchan Kim <minchan.kim@xxxxxxxxx>

Looks good and it passed basic testing.

Reviewed-by: Mel Gorman <mel@xxxxxxxxx>

Thanks

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab
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