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* Re: Linux 2.6.31 - very swap-happy with plenty of free RAM
@ 2009-11-18 21:45 Tomasz Chmielewski
  2009-11-19  0:40 ` Dan Merillat
  0 siblings, 1 reply; 17+ messages in thread
From: Tomasz Chmielewski @ 2009-11-18 21:45 UTC (permalink / raw)
  To: preining, riel, dan.merillat, linux-kernel

Norbert Preining wrote:

> So what normally trashed my system to a quasi halt I tried after a swapoff -a,
> *two* svn up of really big repositories (some Gb), plus starting 
> VirtualBox Windows XP with 1Gb virtual RAM on a 2Gb machine.
> 
> And see hoho, no problem at all. Everything remains responsive and happy.
> The memory was never above 60% in use, but 40% in cache, and all 
> without any problems.
> 
> So that seems to be a real bug.
> 
> I am running currently 2.6.32-rc7, but experienced that already in the
> 31-rc version. Hard to pinpoint exactely where it happens.

Similar here (with 2.6.31.6 kernel).

I have a pretty powerful desktop machine with 8 GB RAM, fast disks with 
RAID-1 etc.

It runs 5 (mostly idle) KVM machines, Firefox, Thunderbird, KDE4, image 
editing program, multiseat X session. Around 6 GB of RAM used when 
caches/buffers are excluded.

Every 10 minutes or so, machine is really unresponsive, load jumps to 10 
or 20. Mouse pointer jumps, it's impossible to change between windows etc.

Do a "swapoff -a", and everything is snappy and responsive as it should, 
there are no more lags.

I noticed that with swap disabled, "Dirty" (in /proc/meminfo) is way 
below 100 MB (usually, 50 MB or so).
With swap enabled, it "Dirty" is usually around 300-500-700 MB, and from 
time to time, the system basically thrashes the disks, and everything is 
unresponsive.
Similar to uncompressing a big tar archive - lots of IO, system 
unresponsive.

BTW, did you try:

echo 0 > /proc/sys/vm/swappiness
swapoff -a
swapon -a


-- 
Tomasz Chmielewski
http://wpkg.org


^ permalink raw reply	[flat|nested] 17+ messages in thread
* complete IO hang since a few kernel revision
@ 2009-10-05  1:16 Norbert Preining
  2009-11-18  7:56 ` Linux 2.6.31 - very swap-happy with plenty of free RAM Dan Merillat
  0 siblings, 1 reply; 17+ messages in thread
From: Norbert Preining @ 2009-10-05  1:16 UTC (permalink / raw)
  To: linux-kernel

Hi everyone,

(please Cc)

kernel 2.6.31.1, 2.6.31.2rc1, 2.6.31, 2.6.30 (at least)
Intel Corporation ICH9M/M-E SATA AHCI


I am experiencing IO stalls of real serious dimensions. I mean up to 20secs
waiting for some operations.

That normally happeny when I do a svn up on a big subversion repository,
but even on other locations.

Yesterday a simple sync took 30sec although I was not doing anything else.

I am *quite* sure that it wasn't like that in former kernel revisions, but
I don't have old ones at hand for testing.

Is there something known about a regression in this area?

Sorry for not Cc-ing the right people, didn't know who it could be.

Thanks a lot for any help/remarks/suggestions

Norbert

-------------------------------------------------------------------------------
Dr. Norbert Preining                                        Associate Professor
JAIST Japan Advanced Institute of Science and Technology   preining@jaist.ac.jp
Vienna University of Technology                               preining@logic.at
Debian Developer (Debian TeX Task Force)                    preining@debian.org
gpg DSA: 0x09C5B094      fp: 14DF 2E6C 0307 BE6D AD76  A9C0 D2BF 4AA3 09C5 B094
-------------------------------------------------------------------------------
QUOYNESS (n.)
The hatefulness of words like 'relionus' and 'easiephit'.
			--- Douglas Adams, The Meaning of Liff

^ permalink raw reply	[flat|nested] 17+ messages in thread

end of thread, other threads:[~2009-12-09 21:18 UTC | newest]

Thread overview: 17+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2009-11-18 21:45 Linux 2.6.31 - very swap-happy with plenty of free RAM Tomasz Chmielewski
2009-11-19  0:40 ` Dan Merillat
2009-11-19  1:09   ` Sven-Haegar Koch
2009-11-19  1:38     ` Dave Chinner
2009-11-19  6:43       ` Tomasz Chmielewski
2009-11-23 21:57         ` Dan Merillat
2009-11-27  1:56   ` Bill Davidsen
  -- strict thread matches above, loose matches on Subject: below --
2009-10-05  1:16 complete IO hang since a few kernel revision Norbert Preining
2009-11-18  7:56 ` Linux 2.6.31 - very swap-happy with plenty of free RAM Dan Merillat
2009-11-18 15:22   ` Rik van Riel
2009-11-18 15:48   ` Norbert Preining
2009-11-19 14:36   ` KOSAKI Motohiro
2009-11-25 23:13     ` Dan Merillat
2009-11-26  1:54       ` Rik van Riel
2009-12-03  4:16         ` Dan Merillat
2009-12-07 20:49           ` Dan Merillat
2009-12-09 20:48             ` Henrique de Moraes Holschuh
2009-12-09 21:18               ` Rik van Riel

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