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From: Mel Gorman <mgorman@suse.de>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>,
	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
	Rik van Riel <riel@redhat.com>,
	Zlatko Calusic <zcalusic@bitsync.net>,
	Johannes Weiner <hannes@cmpxchg.org>,
	dormando <dormando@rydia.net>,
	Satoru Moriya <satoru.moriya@hds.com>,
	Michal Hocko <mhocko@suse.cz>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback
Date: Tue, 19 Mar 2013 10:57:48 +0000	[thread overview]
Message-ID: <20130319105748.GH2055@suse.de> (raw)
In-Reply-To: <5146FC86.2080107@gmail.com>

On Mon, Mar 18, 2013 at 07:37:42PM +0800, Simon Jeons wrote:
> On 03/17/2013 09:04 PM, Mel Gorman wrote:
> >Historically, kswapd used to congestion_wait() at higher priorities if it
> >was not making forward progress. This made no sense as the failure to make
> >progress could be completely independent of IO. It was later replaced by
> >wait_iff_congested() and removed entirely by commit 258401a6 (mm: don't
> >wait on congested zones in balance_pgdat()) as it was duplicating logic
> >in shrink_inactive_list().
> >
> >This is problematic. If kswapd encounters many pages under writeback and
> >it continues to scan until it reaches the high watermark then it will
> >quickly skip over the pages under writeback and reclaim clean young
> >pages or push applications out to swap.
> >
> >The use of wait_iff_congested() is not suited to kswapd as it will only
> >stall if the underlying BDI is really congested or a direct reclaimer was
> >unable to write to the underlying BDI. kswapd bypasses the BDI congestion
> >as it sets PF_SWAPWRITE but even if this was taken into account then it
> 
> Where will check this flag?
> 

may_write_to_queue

-- 
Mel Gorman
SUSE Labs

--
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WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mgorman@suse.de>
To: Simon Jeons <simon.jeons@gmail.com>
Cc: Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>,
	Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
	Rik van Riel <riel@redhat.com>,
	Zlatko Calusic <zcalusic@bitsync.net>,
	Johannes Weiner <hannes@cmpxchg.org>,
	dormando <dormando@rydia.net>,
	Satoru Moriya <satoru.moriya@hds.com>,
	Michal Hocko <mhocko@suse.cz>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback
Date: Tue, 19 Mar 2013 10:57:48 +0000	[thread overview]
Message-ID: <20130319105748.GH2055@suse.de> (raw)
In-Reply-To: <5146FC86.2080107@gmail.com>

On Mon, Mar 18, 2013 at 07:37:42PM +0800, Simon Jeons wrote:
> On 03/17/2013 09:04 PM, Mel Gorman wrote:
> >Historically, kswapd used to congestion_wait() at higher priorities if it
> >was not making forward progress. This made no sense as the failure to make
> >progress could be completely independent of IO. It was later replaced by
> >wait_iff_congested() and removed entirely by commit 258401a6 (mm: don't
> >wait on congested zones in balance_pgdat()) as it was duplicating logic
> >in shrink_inactive_list().
> >
> >This is problematic. If kswapd encounters many pages under writeback and
> >it continues to scan until it reaches the high watermark then it will
> >quickly skip over the pages under writeback and reclaim clean young
> >pages or push applications out to swap.
> >
> >The use of wait_iff_congested() is not suited to kswapd as it will only
> >stall if the underlying BDI is really congested or a direct reclaimer was
> >unable to write to the underlying BDI. kswapd bypasses the BDI congestion
> >as it sets PF_SWAPWRITE but even if this was taken into account then it
> 
> Where will check this flag?
> 

may_write_to_queue

-- 
Mel Gorman
SUSE Labs

  reply	other threads:[~2013-03-19 10:57 UTC|newest]

Thread overview: 258+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-03-17 13:04 [RFC PATCH 0/8] Reduce system disruption due to kswapd Mel Gorman
2013-03-17 13:04 ` Mel Gorman
2013-03-17 13:04 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-18 23:53   ` Simon Jeons
2013-03-18 23:53     ` Simon Jeons
2013-03-19  9:55     ` Mel Gorman
2013-03-19  9:55       ` Mel Gorman
2013-03-19 10:16       ` Simon Jeons
2013-03-19 10:16         ` Simon Jeons
2013-03-19 10:59         ` Mel Gorman
2013-03-19 10:59           ` Mel Gorman
2013-03-20 16:18   ` Michal Hocko
2013-03-20 16:18     ` Michal Hocko
2013-03-21  0:52     ` Rik van Riel
2013-03-21  0:52       ` Rik van Riel
2013-03-22  0:08       ` Will Huck
2013-03-22  0:08         ` Will Huck
2013-03-21  9:47     ` Mel Gorman
2013-03-21  9:47       ` Mel Gorman
2013-03-21 12:59       ` Michal Hocko
2013-03-21 12:59         ` Michal Hocko
2013-03-21  0:51   ` Rik van Riel
2013-03-21  0:51     ` Rik van Riel
2013-03-21 15:57   ` Johannes Weiner
2013-03-21 15:57     ` Johannes Weiner
2013-03-21 16:47     ` Mel Gorman
2013-03-21 16:47       ` Mel Gorman
2013-03-22  0:05     ` Will Huck
2013-03-22  0:05       ` Will Huck
2013-03-22  3:52       ` Rik van Riel
2013-03-22  3:52         ` Rik van Riel
2013-03-22  3:56         ` Will Huck
2013-03-22  3:56           ` Will Huck
2013-03-22  4:59           ` Will Huck
2013-03-22  4:59             ` Will Huck
2013-03-22 13:01             ` Rik van Riel
2013-03-22 13:01               ` Rik van Riel
2013-04-05  0:05               ` Will Huck
2013-04-05  0:05                 ` Will Huck
2013-04-07  7:32                 ` Will Huck
2013-04-07  7:32                   ` Will Huck
2013-04-07  7:35                 ` Will Huck
2013-04-07  7:35                   ` Will Huck
2013-04-11  5:54         ` Will Huck
2013-04-11  5:54           ` Will Huck
2013-04-11  5:58         ` Will Huck
2013-04-11  5:58           ` Will Huck
2013-04-12  5:46           ` Ric Mason
2013-04-12  5:46             ` Ric Mason
2013-04-12  9:34             ` Mel Gorman
2013-04-12  9:34               ` Mel Gorman
2013-04-12 13:40               ` Rik van Riel
2013-04-12 13:40                 ` Rik van Riel
2013-03-25  9:07   ` Michal Hocko
2013-03-25  9:07     ` Michal Hocko
2013-03-25  9:13     ` Jiri Slaby
2013-03-25  9:13       ` Jiri Slaby
2013-03-28 22:31       ` Jiri Slaby
2013-03-28 22:31         ` Jiri Slaby
2013-03-29  8:22         ` Michal Hocko
2013-03-29  8:22           ` Michal Hocko
2013-03-30 22:07           ` Jiri Slaby
2013-03-30 22:07             ` Jiri Slaby
2013-04-02 11:15             ` Mel Gorman
2013-04-02 11:15               ` Mel Gorman
2013-03-17 13:04 ` [PATCH 02/10] mm: vmscan: Obey proportional scanning requirements for kswapd Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-17 14:39   ` Andi Kleen
2013-03-17 14:39     ` Andi Kleen
2013-03-17 15:08     ` Mel Gorman
2013-03-17 15:08       ` Mel Gorman
2013-03-21  1:10   ` Rik van Riel
2013-03-21  1:10     ` Rik van Riel
2013-03-21  9:54     ` Mel Gorman
2013-03-21  9:54       ` Mel Gorman
2013-03-21 14:01   ` Michal Hocko
2013-03-21 14:01     ` Michal Hocko
2013-03-21 14:31     ` Mel Gorman
2013-03-21 14:31       ` Mel Gorman
2013-03-21 15:07       ` Michal Hocko
2013-03-21 15:07         ` Michal Hocko
2013-03-21 15:34         ` Mel Gorman
2013-03-21 15:34           ` Mel Gorman
2013-03-22  7:54           ` Michal Hocko
2013-03-22  7:54             ` Michal Hocko
2013-03-22  8:37             ` Mel Gorman
2013-03-22  8:37               ` Mel Gorman
2013-03-22 10:04               ` Michal Hocko
2013-03-22 10:04                 ` Michal Hocko
2013-03-22 10:47                 ` Michal Hocko
2013-03-22 10:47                   ` Michal Hocko
2013-03-21 16:25   ` Johannes Weiner
2013-03-21 16:25     ` Johannes Weiner
2013-03-21 18:02     ` Mel Gorman
2013-03-21 18:02       ` Mel Gorman
2013-03-22 16:53       ` Johannes Weiner
2013-03-22 16:53         ` Johannes Weiner
2013-03-22 18:25         ` Mel Gorman
2013-03-22 18:25           ` Mel Gorman
2013-03-22 19:09           ` Johannes Weiner
2013-03-22 19:09             ` Johannes Weiner
2013-03-22 19:46             ` Mel Gorman
2013-03-22 19:46               ` Mel Gorman
2013-03-17 13:04 ` [PATCH 03/10] mm: vmscan: Flatten kswapd priority loop Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-17 14:36   ` Andi Kleen
2013-03-17 14:36     ` Andi Kleen
2013-03-17 15:09     ` Mel Gorman
2013-03-17 15:09       ` Mel Gorman
2013-03-18  7:02   ` Hillf Danton
2013-03-19 10:01     ` Mel Gorman
2013-03-18 23:58   ` Simon Jeons
2013-03-18 23:58     ` Simon Jeons
2013-03-19 10:12     ` Mel Gorman
2013-03-19 10:12       ` Mel Gorman
2013-03-19  3:08   ` Simon Jeons
2013-03-19  3:08     ` Simon Jeons
2013-03-19  8:23     ` Michal Hocko
2013-03-19  8:23       ` Michal Hocko
2013-03-19 10:14     ` Mel Gorman
2013-03-19 10:14       ` Mel Gorman
2013-03-19 10:26       ` Simon Jeons
2013-03-19 10:26         ` Simon Jeons
2013-03-19 11:01         ` Mel Gorman
2013-03-19 11:01           ` Mel Gorman
2013-03-21 14:54   ` Michal Hocko
2013-03-21 14:54     ` Michal Hocko
2013-03-21 15:26     ` Mel Gorman
2013-03-21 15:26       ` Mel Gorman
2013-03-21 15:38       ` Michal Hocko
2013-03-21 15:38         ` Michal Hocko
2013-03-17 13:04 ` [PATCH 04/10] mm: vmscan: Decide whether to compact the pgdat based on reclaim progress Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-18 11:11   ` Wanpeng Li
2013-03-18 11:11   ` Wanpeng Li
2013-03-19 10:19     ` Mel Gorman
2013-03-19 10:19       ` Mel Gorman
2013-03-18 11:35   ` Hillf Danton
2013-03-18 11:35     ` Hillf Danton
2013-03-19 10:27     ` Mel Gorman
2013-03-19 10:27       ` Mel Gorman
2013-03-21 15:32   ` Michal Hocko
2013-03-21 15:32     ` Michal Hocko
2013-03-21 15:47     ` Mel Gorman
2013-03-21 15:47       ` Mel Gorman
2013-03-21 15:50       ` Michal Hocko
2013-03-21 15:50         ` Michal Hocko
2013-03-17 13:04 ` [PATCH 05/10] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-21  1:20   ` Rik van Riel
2013-03-21  1:20     ` Rik van Riel
2013-03-21 10:12     ` Mel Gorman
2013-03-21 10:12       ` Mel Gorman
2013-03-21 12:30       ` Rik van Riel
2013-03-21 12:30         ` Rik van Riel
2013-03-21 15:48   ` Michal Hocko
2013-03-21 15:48     ` Michal Hocko
2013-03-17 13:04 ` [PATCH 06/10] mm: vmscan: Have kswapd writeback pages based on dirty pages encountered, not priority Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-17 14:42   ` Andi Kleen
2013-03-17 14:42     ` Andi Kleen
2013-03-17 15:11     ` Mel Gorman
2013-03-17 15:11       ` Mel Gorman
2013-03-21 17:53       ` Rik van Riel
2013-03-21 17:53         ` Rik van Riel
2013-03-21 18:15         ` Mel Gorman
2013-03-21 18:15           ` Mel Gorman
2013-03-21 18:21           ` Rik van Riel
2013-03-21 18:21             ` Rik van Riel
2013-03-18 11:08   ` Wanpeng Li
2013-03-19 10:35     ` Mel Gorman
2013-03-19 10:35       ` Mel Gorman
2013-03-18 11:08   ` Wanpeng Li
2013-03-17 13:04 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-17 14:49   ` Andi Kleen
2013-03-17 14:49     ` Andi Kleen
2013-03-17 15:19     ` Mel Gorman
2013-03-17 15:19       ` Mel Gorman
2013-03-17 15:40       ` Andi Kleen
2013-03-17 15:40         ` Andi Kleen
2013-03-19 11:06         ` Mel Gorman
2013-03-19 11:06           ` Mel Gorman
2013-03-18 11:37   ` Simon Jeons
2013-03-18 11:37     ` Simon Jeons
2013-03-19 10:57     ` Mel Gorman [this message]
2013-03-19 10:57       ` Mel Gorman
2013-03-18 11:58   ` Wanpeng Li
2013-03-19 10:58     ` Mel Gorman
2013-03-19 10:58       ` Mel Gorman
2013-03-18 11:58   ` Wanpeng Li
2013-03-21 16:32   ` [PATCH 07/10 -v2r1] " Michal Hocko
2013-03-21 16:32     ` Michal Hocko
2013-03-21 18:42   ` [PATCH 07/10] " Rik van Riel
2013-03-21 18:42     ` Rik van Riel
2013-03-22  8:27     ` Mel Gorman
2013-03-22  8:27       ` Mel Gorman
2013-03-17 13:04 ` [PATCH 08/10] mm: vmscan: Have kswapd shrink slab only once per priority Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-17 14:53   ` Andi Kleen
2013-03-17 14:53     ` Andi Kleen
2013-03-21 16:47   ` Michal Hocko
2013-03-21 16:47     ` Michal Hocko
2013-03-21 19:47   ` Rik van Riel
2013-03-21 19:47     ` Rik van Riel
2013-04-09  6:53   ` Joonsoo Kim
2013-04-09  6:53     ` Joonsoo Kim
2013-04-09  8:41     ` Simon Jeons
2013-04-09  8:41       ` Simon Jeons
2013-04-09 11:13     ` Mel Gorman
2013-04-09 11:13       ` Mel Gorman
2013-04-10  1:07       ` Dave Chinner
2013-04-10  1:07         ` Dave Chinner
2013-04-10  5:23         ` Joonsoo Kim
2013-04-10  5:23           ` Joonsoo Kim
2013-04-11  9:53         ` Mel Gorman
2013-04-11  9:53           ` Mel Gorman
2013-04-10  5:21       ` Joonsoo Kim
2013-04-10  5:21         ` Joonsoo Kim
2013-04-11 10:01         ` Mel Gorman
2013-04-11 10:01           ` Mel Gorman
2013-04-11 10:29           ` Ric Mason
2013-04-11 10:29             ` Ric Mason
2013-03-17 13:04 ` [PATCH 09/10] mm: vmscan: Check if kswapd should writepage " Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-21 16:58   ` Michal Hocko
2013-03-21 16:58     ` Michal Hocko
2013-03-21 18:07     ` Mel Gorman
2013-03-21 18:07       ` Mel Gorman
2013-03-21 19:52   ` Rik van Riel
2013-03-21 19:52     ` Rik van Riel
2013-03-17 13:04 ` [PATCH 10/10] mm: vmscan: Move logic from balance_pgdat() to kswapd_shrink_zone() Mel Gorman
2013-03-17 13:04   ` Mel Gorman
2013-03-17 14:55   ` Andi Kleen
2013-03-17 14:55     ` Andi Kleen
2013-03-17 15:25     ` Mel Gorman
2013-03-17 15:25       ` Mel Gorman
2013-03-21 17:18   ` Michal Hocko
2013-03-21 17:18     ` Michal Hocko
2013-03-21 18:13     ` Mel Gorman
2013-03-21 18:13       ` Mel Gorman
2013-03-21 10:44 ` [RFC PATCH 0/8] Reduce system disruption due to kswapd Damien Wyart
2013-03-21 10:54   ` Zlatko Calusic
2013-03-21 11:48     ` Mel Gorman
2013-03-21 11:20   ` Mel Gorman
2013-03-22 14:37 ` Mel Gorman
2013-03-22 14:37   ` Mel Gorman
2013-03-24 19:00 ` Jiri Slaby
2013-03-24 19:00   ` Jiri Slaby
2013-03-25  8:17   ` Michal Hocko
2013-03-25  8:17     ` Michal Hocko
  -- strict thread matches above, loose matches on Subject: below --
2013-04-09 11:06 [PATCH 0/10] Reduce system disruption due to kswapd V2 Mel Gorman
2013-04-09 11:07 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-04-09 11:07   ` Mel Gorman
2013-04-12  2:54   ` Rik van Riel
2013-04-12  2:54     ` Rik van Riel
2013-04-11 19:57 [PATCH 0/10] Reduce system disruption due to kswapd V3 Mel Gorman
2013-04-11 19:57 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-04-11 19:57   ` Mel Gorman

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