Re: [PATCH 2/7] vmscan: synchronous lumpy reclaim don't callcongestion_wait()

From: Minchan Kim
Date: Thu Aug 05 2010 - 09:55:29 EST


On Thu, Aug 05, 2010 at 03:13:03PM +0900, KOSAKI Motohiro wrote:
> congestion_wait() mean "waiting quueue congestion is cleared".
> That said, if the system have plenty dirty pages and flusher thread push
> new request to IO queue conteniously, IO queue are not cleared
> congestion status for long time. thus, congestion_wait(HZ/10) become
> almostly equivalent schedule_timeout(HZ/10).
>
> However, synchronous lumpy reclaim donesn't need this
> congestion_wait() at all. shrink_page_list(PAGEOUT_IO_SYNC) are
> using wait_on_page_writeback() and it provide sufficient waiting.
>
> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@xxxxxxxxxxxxxx>
Reviewed-by: Minchan Kim <minchan.kim@xxxxxxxxx>

--
Kind regards,
Minchan Kim
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