From: Mel Gorman <mel@csn.ul.ie>
To: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
Linux Kernel List <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Minchan Kim <minchan.kim@gmail.com>,
Wu Fengguang <fengguang.wu@intel.com>,
Andrea Arcangeli <aarcange@redhat.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Dave Chinner <david@fromorbit.com>,
Chris Mason <chris.mason@oracle.com>,
Christoph Hellwig <hch@lst.de>,
Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 0/9] Reduce latencies and improve overall reclaim efficiency v1
Date: Wed, 8 Sep 2010 09:38:51 +0100 [thread overview]
Message-ID: <20100908083851.GA29263@csn.ul.ie> (raw)
In-Reply-To: <20100908115807.C916.A69D9226@jp.fujitsu.com>
On Wed, Sep 08, 2010 at 12:14:29PM +0900, KOSAKI Motohiro wrote:
> > There have been numerous reports of stalls that pointed at the problem being
> > somewhere in the VM. There are multiple roots to the problems which means
> > dealing with any of the root problems in isolation is tricky to justify on
> > their own and they would still need integration testing. This patch series
> > gathers together three different patch sets which in combination should
> > tackle some of the root causes of latency problems being reported.
> >
> > The first patch improves vmscan latency by tracking when pages get reclaimed
> > by shrink_inactive_list. For this series, the most important results is
> > being able to calculate the scanning/reclaim ratio as a measure of the
> > amount of work being done by page reclaim.
> >
> > Patches 2 and 3 account for the time spent in congestion_wait() and avoids
> > calling going to sleep on congestion when it is unnecessary. This is expected
> > to reduce stalls in situations where the system is under memory pressure
> > but not due to congestion.
> >
> > Patches 4-8 were originally developed by Kosaki Motohiro but reworked for
> > this series. It has been noted that lumpy reclaim is far too aggressive and
> > trashes the system somewhat. As SLUB uses high-order allocations, a large
> > cost incurred by lumpy reclaim will be noticeable. It was also reported
> > during transparent hugepage support testing that lumpy reclaim was trashing
> > the system and these patches should mitigate that problem without disabling
> > lumpy reclaim.
>
> Wow, I'm sorry my lazyness bother you. I'll join to test this patch series
> ASAP and take a feedback soon.
>
It did not bother me at all. I generally agreed with the direction and
it seemed sensible to take them into consideration before patches 9 and
10 in particular and make sure they all played nicely together.
--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab
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next prev parent reply other threads:[~2010-09-08 8:38 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-06 10:47 [PATCH 0/9] Reduce latencies and improve overall reclaim efficiency v1 Mel Gorman
2010-09-06 10:47 ` [PATCH 01/10] tracing, vmscan: Add trace events for LRU list shrinking Mel Gorman
2010-09-06 10:47 ` [PATCH 02/10] writeback: Account for time spent congestion_waited Mel Gorman
2010-09-06 10:47 ` [PATCH 03/10] writeback: Do not congestion sleep if there are no congested BDIs or significant writeback Mel Gorman
2010-09-07 15:25 ` Minchan Kim
2010-09-08 11:04 ` Mel Gorman
2010-09-08 14:52 ` Minchan Kim
2010-09-09 8:54 ` Mel Gorman
2010-09-12 15:37 ` Minchan Kim
2010-09-13 8:55 ` Mel Gorman
2010-09-13 9:48 ` Minchan Kim
2010-09-13 10:07 ` Mel Gorman
2010-09-13 10:20 ` Minchan Kim
2010-09-13 10:30 ` Mel Gorman
2010-09-08 21:23 ` Andrew Morton
2010-09-09 10:43 ` Mel Gorman
2010-09-09 3:02 ` KAMEZAWA Hiroyuki
2010-09-09 8:58 ` Mel Gorman
2010-09-06 10:47 ` [PATCH 04/10] vmscan: Synchronous lumpy reclaim should not call congestion_wait() Mel Gorman
2010-09-07 15:26 ` Minchan Kim
2010-09-08 6:15 ` Johannes Weiner
2010-09-08 11:25 ` Wu Fengguang
2010-09-09 3:03 ` KAMEZAWA Hiroyuki
2010-09-06 10:47 ` [PATCH 05/10] vmscan: Synchrounous lumpy reclaim use lock_page() instead trylock_page() Mel Gorman
2010-09-07 15:28 ` Minchan Kim
2010-09-08 6:16 ` Johannes Weiner
2010-09-08 11:28 ` Wu Fengguang
2010-09-09 3:04 ` KAMEZAWA Hiroyuki
2010-09-09 3:15 ` KAMEZAWA Hiroyuki
2010-09-09 3:25 ` Wu Fengguang
2010-09-09 4:13 ` KOSAKI Motohiro
2010-09-09 9:22 ` Mel Gorman
2010-09-10 10:25 ` KOSAKI Motohiro
2010-09-10 10:33 ` KOSAKI Motohiro
2010-09-13 9:14 ` Mel Gorman
2010-09-14 10:14 ` KOSAKI Motohiro
2010-09-06 10:47 ` [PATCH 06/10] vmscan: Narrow the scenarios lumpy reclaim uses synchrounous reclaim Mel Gorman
2010-09-09 3:14 ` KAMEZAWA Hiroyuki
2010-09-06 10:47 ` [PATCH 07/10] vmscan: Remove dead code in shrink_inactive_list() Mel Gorman
2010-09-07 15:33 ` Minchan Kim
2010-09-06 10:47 ` [PATCH 08/10] vmscan: isolated_lru_pages() stop neighbour search if neighbour cannot be isolated Mel Gorman
2010-09-07 15:37 ` Minchan Kim
2010-09-08 11:12 ` Mel Gorman
2010-09-08 14:58 ` Minchan Kim
2010-09-08 11:37 ` Wu Fengguang
2010-09-08 12:50 ` Mel Gorman
2010-09-08 13:14 ` Wu Fengguang
2010-09-08 13:27 ` Mel Gorman
2010-09-09 3:17 ` KAMEZAWA Hiroyuki
2010-09-06 10:47 ` [PATCH 09/10] vmscan: Do not writeback filesystem pages in direct reclaim Mel Gorman
2010-09-13 13:31 ` Wu Fengguang
2010-09-13 13:55 ` Mel Gorman
2010-09-13 14:33 ` Wu Fengguang
2010-10-28 21:50 ` Christoph Hellwig
2010-10-29 10:26 ` Mel Gorman
2010-09-06 10:47 ` [PATCH 10/10] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages Mel Gorman
2010-09-09 3:22 ` KAMEZAWA Hiroyuki
2010-09-09 9:32 ` Mel Gorman
2010-09-13 0:53 ` KAMEZAWA Hiroyuki
2010-09-13 13:48 ` Wu Fengguang
2010-09-13 14:10 ` Mel Gorman
2010-09-13 14:41 ` Wu Fengguang
2010-09-06 10:49 ` [PATCH 0/9] Reduce latencies and improve overall reclaim efficiency v1 Mel Gorman
2010-09-08 3:14 ` KOSAKI Motohiro
2010-09-08 8:38 ` Mel Gorman [this message]
2010-09-13 23:10 ` Minchan Kim
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