Re: [PATCH 08/14] mm, compaction: Abstract compaction feedback to helpers

[Vlastimil Babka]

On 04/20/2016 09:47 PM, Michal Hocko wrote:
> From: Michal Hocko <mhocko@xxxxxxxx>
>
> Compaction can provide a wild variation of feedback to the caller. Many
> of them are implementation specific and the caller of the compaction
> (especially the page allocator) shouldn't be bound to specifics of the
> current implementation.
>
> This patch abstracts the feedback into three basic types:
> 	- compaction_made_progress - compaction was active and made some
> 	  progress.
> 	- compaction_failed - compaction failed and further attempts to
> 	  invoke it would most probably fail and therefore it is not
> 	  worth retrying
> 	- compaction_withdrawn - compaction wasn't invoked for an
>            implementation specific reasons. In the current implementation
>            it means that the compaction was deferred, contended or the
>            page scanners met too early without any progress. Retrying is
>            still worthwhile.
>
> [vbabka@xxxxxxx: do not change thp back off behavior]
> Signed-off-by: Michal Hocko <mhocko@xxxxxxxx>

Acked-by: Vlastimil Babka <vbabka@xxxxxxx>