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* 2.4.20-18 size-4096 memory leaks
@ 2003-11-26  9:29 yuval yeret
  2003-11-26 10:11 ` Henrik Storner
  2003-11-26 11:51 ` Stephen C. Tweedie
  0 siblings, 2 replies; 7+ messages in thread
From: yuval yeret @ 2003-11-26  9:29 UTC (permalink / raw)
  To: linux-kernel

Hi,

I'm seeing a constant leak in size-4096 on a machine running 2.4.20-18 SMP 
BIGMEM, which might / might not be related to the machine finally going out 
of memory and going into a hang.

I saw a discussion around similar problems in 2.6.0 (2.6.0-test5/6 (and 
probably 7 too) size-4096 memory leak - http://lkml.org/lkml/2003/10/17/5 )
and an ext3 patch was suggested by Andrew Morton.

>From a brief look the code in 2.4 it seems like the patch might be relevant 
here as well. Is the size-4096 leak a known issue for 2.4 ?
Is the 2.6 patch applicable in 2.4 as well ?


Thanks,

--
Yuval Yeret
Yuval at exanet dot com
Exanet
http://www.exanet.com

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^ permalink raw reply	[flat|nested] 7+ messages in thread
* 2.4.20-18 size-4096 memory leaks
@ 2003-11-26 10:24 yuval yeret
  0 siblings, 0 replies; 7+ messages in thread
From: yuval yeret @ 2003-11-26 10:24 UTC (permalink / raw)
  To: linux-kernel

(hopefully plain text this time)

Hi,
I'm seeing a constant leak in size-4096 on a machine running 2.4.20-18 SMP 
BIGMEM, which might / might not be related to the machine finally going out 
of memory and going into a hang.
I saw a discussion around similar problems in 2.6.0 (2.6.0-test5/6 (and 
probably 7 too) size-4096 memory leak - http://lkml.org/lkml/2003/10/17/5 )
and an ext3 patch was suggested by Andrew Morton.
>From a brief look the code in 2.4 it seems like the patch might be relevant 
here as well. Is the size-4096 leak a known issue for 2.4 ?
Is the 2.6 patch applicable in 2.4 as well ?
Thanks,
--
Yuval Yeret
Yuval at exanet dot com
Exanet
http://www.exanet.com

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^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: 2.4.20-18 size-4096 memory leaks
@ 2003-11-26 10:57 Jean Delvare
  2003-11-26 11:57 ` Stephen C. Tweedie
  0 siblings, 1 reply; 7+ messages in thread
From: Jean Delvare @ 2003-11-26 10:57 UTC (permalink / raw)
  To: yuval yeret; +Cc: LKML

Hi Yuval, hi list,

> I'm seeing a constant leak in size-4096 on a machine running
> 2.4.20-18 SMP BIGMEM, which might / might not be related to the
> machine finally going out of memory and going into a hang.

I just wanted to let you know that I have been experiencing similar
leaks. So far, I wasn't enable to find where the leak was, but your
theory matches my observations:

1* On two systems running 2.4.20-2.4.22 kernels, I observed that the
free memory as reported by top was going down regularly, by blocks of 4
or 8kB at an average rate of 90kB/min. Sometimes the value would
stabilize, but I couldn't understand why. What was lost as "free"
memory
increased "buffers" from the same amount. Still that value doesn't
exceed a few dozen MB and sometimes goes does by large blocks, so I was
wondering if there was a real leak or if it was just some kind of
regular prebuffering.

2* On two other, seemingly similar systems, the memory leak wouldn't
occur. It happens that these two systems do *not* use ext3, while the
fisrt two *do* use ext3.

3* The leak isn't distribution specific. I experienced it on both a
Mandrake-shipped kernel and a self-compiled one on a Slackware system.

Your theory that it comes from the ext3 driver makes full sense. I'll
confirm that later today, by using ext2 only on one of the leaking
systems (without changing kernels of course).

The other leaking system is used as a development server. It used to
become very slow after several days. We are now restarting it every
monday and have no significant slowdown anymore. Having other things to
do, I stopped my experiments there, but could do some more now if it
can help.

-- 
Jean Delvare
http://www.ensicaen.ismra.fr/~delvare/

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^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: 2.4.20-18 size-4096 memory leaks
@ 2003-11-26 14:14 yuval yeret
  0 siblings, 0 replies; 7+ messages in thread
From: yuval yeret @ 2003-11-26 14:14 UTC (permalink / raw)
  To: sct, khali; +Cc: linux-kernel, yuval


>From: "Stephen C. Tweedie" <sct@redhat.com>
>
>That's not a leak, it simply sounds like cache effects.  atime updates
>result in journal commits under ext3, and those use at least a couple of
>buffers at a time (one for the metadata descriptor block in the journal,
>one for the journal commit.)  Those aren't leaks --- they are temporary
>use of cache, and once the IO has complete the memory can be immediately
>reclaimed by the kernel if it is needed for anything else.

I'm using noatime for my ext3 mount points ...

>
>Cheers,
>  Stephen
>
>

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^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2003-11-26 14:14 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2003-11-26  9:29 2.4.20-18 size-4096 memory leaks yuval yeret
2003-11-26 10:11 ` Henrik Storner
2003-11-26 11:51 ` Stephen C. Tweedie
2003-11-26 10:24 yuval yeret
2003-11-26 10:57 Jean Delvare
2003-11-26 11:57 ` Stephen C. Tweedie
2003-11-26 14:14 yuval yeret

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