From: Mel Gorman <mgorman@suse.de>
To: Ric Mason <ric.masonn@gmail.com>
Cc: Will Huck <will.huckk@gmail.com>, Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Linux-MM <linux-mm@kvack.org>, Jiri Slaby <jslaby@suse.cz>,
Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
Zlatko Calusic <zcalusic@bitsync.net>,
dormando <dormando@rydia.net>,
Satoru Moriya <satoru.moriya@hds.com>,
Michal Hocko <mhocko@suse.cz>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority
Date: Fri, 12 Apr 2013 10:34:20 +0100 [thread overview]
Message-ID: <20130412093420.GG11656@suse.de> (raw)
In-Reply-To: <51679FAE.7090504@gmail.com>
On Fri, Apr 12, 2013 at 01:46:22PM +0800, Ric Mason wrote:
> Ping Rik, I also want to know the answer. ;-)
This question, like a *lot* of list traffic recently, is a "how long is a
piece of string" with hints that it is an important question but really
is just going to waste a developers time because the question lacks any
relevant meaning. The Inter-Reference Distance (IRD) is mentioned as a
problem but gives no context as to why it is perceived as a problem. IRD is
the distance in time or events between two references of the same page and
is a function of the workload and an arbitrary page, not the page reclaim
algorithm. A page algorithm may take IRD into account but IRD is not and
cannot be a "problem" so the question framing is already confusing.
Furthermore, the upsides and downsides of any given page reclaim algorithm
are complex but in most cases are discussed in the academic pages describing
them. People who are interested need to research and read these papers
and then see how it might apply to the algorithm implemented in Linux or
alternatively investigate what important workloads Linux treats badly
and addressing the problem. The result of such research (and patches)
is then a relevant discussion.
This question asks what the "downside" is versus anonymous pages. To me
the question lacks any meaning because how can a page reclaim algorithm
"against" anonymous pages? As the question lacks meaning, answering it is
impossible and it is effectively asking a developer to write a small paper
to try and discover the meaning of the question before then answering it.
I do not speak for Rik but I at least am ignoring most of these questions
because there is not enough time in the day already. Pings are not
likely to change my opinion.
--
Mel Gorman
SUSE Labs
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next prev parent reply other threads:[~2013-04-12 9:34 UTC|newest]
Thread overview: 136+ 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 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
2013-03-18 23:53 ` Simon Jeons
2013-03-19 9:55 ` Mel Gorman
2013-03-19 10:16 ` Simon Jeons
2013-03-19 10:59 ` Mel Gorman
2013-03-20 16:18 ` Michal Hocko
2013-03-21 0:52 ` Rik van Riel
2013-03-22 0:08 ` Will Huck
2013-03-21 9:47 ` Mel Gorman
2013-03-21 12:59 ` Michal Hocko
2013-03-21 0:51 ` Rik van Riel
2013-03-21 15:57 ` Johannes Weiner
2013-03-21 16:47 ` Mel Gorman
2013-03-22 0:05 ` Will Huck
2013-03-22 3:52 ` Rik van Riel
2013-03-22 3:56 ` Will Huck
2013-03-22 4:59 ` Will Huck
2013-03-22 13:01 ` Rik van Riel
2013-04-05 0:05 ` Will Huck
2013-04-07 7:32 ` Will Huck
2013-04-07 7:35 ` Will Huck
2013-04-11 5:54 ` Will Huck
2013-04-11 5:58 ` Will Huck
2013-04-12 5:46 ` Ric Mason
2013-04-12 9:34 ` Mel Gorman [this message]
2013-04-12 13:40 ` Rik van Riel
2013-03-25 9:07 ` Michal Hocko
2013-03-25 9:13 ` Jiri Slaby
2013-03-28 22:31 ` Jiri Slaby
2013-03-29 8:22 ` Michal Hocko
2013-03-30 22:07 ` Jiri Slaby
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 14:39 ` Andi Kleen
2013-03-17 15:08 ` Mel Gorman
2013-03-21 1:10 ` Rik van Riel
2013-03-21 9:54 ` Mel Gorman
2013-03-21 14:01 ` Michal Hocko
2013-03-21 14:31 ` Mel Gorman
2013-03-21 15:07 ` Michal Hocko
2013-03-21 15:34 ` Mel Gorman
2013-03-22 7:54 ` Michal Hocko
2013-03-22 8:37 ` Mel Gorman
2013-03-22 10:04 ` Michal Hocko
2013-03-22 10:47 ` Michal Hocko
2013-03-21 16:25 ` Johannes Weiner
2013-03-21 18:02 ` Mel Gorman
2013-03-22 16:53 ` Johannes Weiner
2013-03-22 18:25 ` Mel Gorman
2013-03-22 19:09 ` Johannes Weiner
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 14:36 ` Andi Kleen
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
2013-03-19 10:12 ` Mel Gorman
2013-03-19 3:08 ` Simon Jeons
2013-03-19 8:23 ` Michal Hocko
2013-03-19 10:14 ` Mel Gorman
2013-03-19 10:26 ` Simon Jeons
2013-03-19 11:01 ` Mel Gorman
2013-03-21 14:54 ` Michal Hocko
2013-03-21 15:26 ` Mel Gorman
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
2013-03-18 11:11 ` Wanpeng Li
2013-03-19 10:19 ` Mel Gorman
2013-03-18 11:11 ` Wanpeng Li
2013-03-18 11:35 ` Hillf Danton
2013-03-19 10:27 ` Mel Gorman
2013-03-21 15:32 ` Michal Hocko
2013-03-21 15:47 ` Mel Gorman
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
2013-03-21 1:20 ` Rik van Riel
2013-03-21 10:12 ` Mel Gorman
2013-03-21 12:30 ` Rik van Riel
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 14:42 ` Andi Kleen
2013-03-17 15:11 ` Mel Gorman
2013-03-21 17:53 ` Rik van Riel
2013-03-21 18:15 ` Mel Gorman
2013-03-21 18:21 ` Rik van Riel
2013-03-18 11:08 ` Wanpeng Li
2013-03-18 11:08 ` Wanpeng Li
2013-03-19 10:35 ` Mel Gorman
2013-03-17 13:04 ` [PATCH 07/10] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-03-17 14:49 ` Andi Kleen
2013-03-17 15:19 ` Mel Gorman
2013-03-17 15:40 ` Andi Kleen
2013-03-19 11:06 ` Mel Gorman
2013-03-18 11:37 ` Simon Jeons
2013-03-19 10:57 ` Mel Gorman
2013-03-18 11:58 ` Wanpeng Li
2013-03-18 11:58 ` Wanpeng Li
2013-03-19 10:58 ` Mel Gorman
2013-03-21 16:32 ` [PATCH 07/10 -v2r1] " Michal Hocko
2013-03-21 18:42 ` [PATCH 07/10] " Rik van Riel
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 14:53 ` Andi Kleen
2013-03-21 16:47 ` Michal Hocko
2013-03-21 19:47 ` Rik van Riel
2013-04-09 6:53 ` Joonsoo Kim
2013-04-09 8:41 ` Simon Jeons
2013-04-09 11:13 ` Mel Gorman
2013-04-10 1:07 ` Dave Chinner
2013-04-10 5:23 ` Joonsoo Kim
2013-04-11 9:53 ` Mel Gorman
2013-04-10 5:21 ` Joonsoo Kim
2013-04-11 10:01 ` Mel Gorman
2013-04-11 10:29 ` Ric Mason
2013-03-17 13:04 ` [PATCH 09/10] mm: vmscan: Check if kswapd should writepage " Mel Gorman
2013-03-21 16:58 ` Michal Hocko
2013-03-21 18:07 ` Mel Gorman
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 14:55 ` Andi Kleen
2013-03-17 15:25 ` Mel Gorman
2013-03-21 17:18 ` Michal Hocko
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
2013-03-24 19:00 ` Jiri Slaby
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 11:06 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
2013-04-09 13:27 ` Michal Hocko
2013-04-10 6:47 ` Kamezawa Hiroyuki
2013-04-11 19:57 [PATCH 0/10] Reduce system disruption due to kswapd V3 Mel Gorman
2013-04-11 19:57 ` [PATCH 01/10] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
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