From: Florian Fainelli <f.fainelli@gmail.com>
To: Mel Gorman <mgorman@suse.de>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
mhocko <mhocko@suse.cz>, hannes <hannes@cmpxchg.org>,
riel <riel@redhat.com>, linux-mm <linux-mm@kvack.org>,
"m.szyprowski" <m.szyprowski@samsung.com>,
"marc.ceeeee" <marc.ceeeee@gmail.com>
Subject: Re: high kswapd CPU usage when executing binaries from NFS w/ CMA and COMPACTION
Date: Fri, 6 Dec 2013 14:51:00 -0800 [thread overview]
Message-ID: <CAGVrzcYMSVX=xkVqROjouvHpVup+jO00Wb66h2Wd=LFX47rDiw@mail.gmail.com> (raw)
In-Reply-To: <20131204130038.GY11295@suse.de>
2013/12/4 Mel Gorman <mgorman@suse.de>:
> On Tue, Dec 03, 2013 at 06:30:28PM -0800, Florian Fainelli wrote:
>> Hi all,
>>
>> I am experiencing high kswapd CPU usage on an ARMv7 system running
>> 3.8.13 when executing relatively large binaries from NFS. When this
>> happens kswapd consumes around 55-60% CPU usage and the applications
>> takes a huge time to load.
>>
>
> There were a number of changes made related to how and when kswapd
> stalls, particularly when pages are dirty. Brief check confirms that
>
> git log v3.8..v3.12 --pretty=one --author "Mel Gorman" mm/vmscan.c
>
> NFS dirty pages are problematic for compaction as dirty pages cannot be
> migrated until cleaned. I'd suggest checking if current mainline suffers
> the same problem and if not, focus on patches related to dirty page
> handling and kswapd throttling in mm/vmscan.c as backport candidates.
I have just backported these patches to 3.8.13 and am still seeing the
problem, although kswapd usage dropped considerably (by half
approximately). Will keep you updated once I have properly tested
current mainline on my platform. Thanks!
--
Florian
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prev parent reply other threads:[~2013-12-06 22:51 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-04 2:30 Florian Fainelli
2013-12-04 13:00 ` Mel Gorman
2013-12-06 22:51 ` Florian Fainelli [this message]
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