From: Zlatko Calusic <zcalusic@bitsync.net>
To: Andrew Morton <akpm@linux-foundation.org>, Mel Gorman <mgorman@suse.de>
Cc: Jiri Slaby <jslaby@suse.cz>,
Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
Rik van Riel <riel@redhat.com>,
Johannes Weiner <hannes@cmpxchg.org>,
dormando <dormando@rydia.net>, Michal Hocko <mhocko@suse.cz>,
Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/9] Reduce system disruption due to kswapd V4
Date: Sat, 18 May 2013 23:15:34 +0200 [thread overview]
Message-ID: <5197EF76.2070504@bitsync.net> (raw)
In-Reply-To: <20130515133748.5db2c6fb61c72ec61381d941@linux-foundation.org>
[-- Attachment #1: Type: text/plain, Size: 2238 bytes --]
On 15.05.2013 22:37, Andrew Morton wrote:
>>
>> 3.10.0-rc1 3.10.0-rc1
>> vanilla lessdisrupt-v4
>> Page Ins 1234608 101892
>> Page Outs 12446272 11810468
>> Swap Ins 283406 0
>> Swap Outs 698469 27882
>> Direct pages scanned 0 136480
>> Kswapd pages scanned 6266537 5369364
>> Kswapd pages reclaimed 1088989 930832
>> Direct pages reclaimed 0 120901
>> Kswapd efficiency 17% 17%
>> Kswapd velocity 5398.371 4635.115
>> Direct efficiency 100% 88%
>> Direct velocity 0.000 117.817
>> Percentage direct scans 0% 2%
>> Page writes by reclaim 1655843 4009929
>> Page writes file 957374 3982047
>> Page writes anon 698469 27882
>> Page reclaim immediate 5245 1745
>> Page rescued immediate 0 0
>> Slabs scanned 33664 25216
>> Direct inode steals 0 0
>> Kswapd inode steals 19409 778
>
> The reduction in inode steals might be a significant thing?
> prune_icache_sb() does invalidate_mapping_pages() and can have the bad
> habit of shooting down a vast number of pagecache pages (for a large
> file) in a single hit. Did this workload use large (and clean) files?
> Did you run any test which would expose this effect?
>
I did not run specific tests, but I believe I observed exactly this
issue on the real workload, where even at a moderate load sudden frees
of pagecache happen quite often. I've attached a small graph where it
can be easily seen. The snapshot was taken while the server was running
an unpatched Linus kernel. After the Mel's patch series is applied, I
can't see anything similar. So it seems that this issue is completely
gone, Mel's done a wonderful job.
And BTW, V4 continues to be rock stable, running here on many different
machines, so I look forward seeing this code merged in 3.11.
--
Zlatko
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next prev parent reply other threads:[~2013-05-18 21:15 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-13 8:12 [PATCH 0/9] Reduce system disruption due to kswapd V4 Mel Gorman
2013-05-13 8:12 ` [PATCH 1/9] mm: vmscan: Limit the number of pages kswapd reclaims at each priority Mel Gorman
2013-05-13 8:12 ` [PATCH 2/9] mm: vmscan: Obey proportional scanning requirements for kswapd Mel Gorman
2013-05-14 10:21 ` Michal Hocko
2013-05-17 3:41 ` Kamezawa Hiroyuki
2013-05-13 8:12 ` [PATCH 3/9] mm: vmscan: Flatten kswapd priority loop Mel Gorman
2013-05-14 10:38 ` Michal Hocko
2013-05-13 8:12 ` [PATCH 4/9] mm: vmscan: Decide whether to compact the pgdat based on reclaim progress Mel Gorman
2013-05-14 10:51 ` Michal Hocko
2013-05-13 8:12 ` [PATCH 5/9] mm: vmscan: Do not allow kswapd to scan at maximum priority Mel Gorman
2013-05-13 8:12 ` [PATCH 6/9] mm: vmscan: Have kswapd writeback pages based on dirty pages encountered, not priority Mel Gorman
2013-05-14 11:25 ` Michal Hocko
2013-05-13 8:12 ` [PATCH 7/9] mm: vmscan: Block kswapd if it is encountering pages under writeback Mel Gorman
2013-05-14 21:06 ` Rik van Riel
2013-05-15 21:39 ` Andrew Morton
2013-05-16 13:07 ` Mel Gorman
2013-05-13 8:12 ` [PATCH 8/9] mm: vmscan: Check if kswapd should writepage once per pgdat scan Mel Gorman
2013-05-13 8:12 ` [PATCH 9/9] mm: vmscan: Move logic from balance_pgdat() to kswapd_shrink_zone() Mel Gorman
2013-05-14 12:23 ` Michal Hocko
2013-05-14 21:06 ` Rik van Riel
2013-05-15 20:37 ` [PATCH 0/9] Reduce system disruption due to kswapd V4 Andrew Morton
2013-05-16 10:33 ` Mel Gorman
2013-05-16 13:54 ` Michal Hocko
2013-05-16 14:11 ` Mel Gorman
2013-05-18 21:15 ` Zlatko Calusic [this message]
2013-05-21 23:13 ` Dave Chinner
2013-05-22 8:48 ` Mel Gorman
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