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From: Jan Harkes <jaharkes@cs.cmu.edu>
To: Josh Grebe <squash@primary.net>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Question about memory usage in 2.4 vs 2.2
Date: Tue, 20 Mar 2001 13:54:49 -0500	[thread overview]
Message-ID: <20010320135449.A24252@cs.cmu.edu> (raw)
In-Reply-To: <200103190207.UAA13397@senechalle.net> <Pine.LNX.4.21.0103201038140.2405-100000@scarface.primary.net>
In-Reply-To: <Pine.LNX.4.21.0103201038140.2405-100000@scarface.primary.net>; from squash@primary.net on Tue, Mar 20, 2001 at 11:01:52AM -0600

On Tue, Mar 20, 2001 at 11:01:52AM -0600, Josh Grebe wrote:
> Greetings,
> 
> I have a server farm made of identical hardware running pop3 and imap mail
> functions. recently, we upgraded all the machines to kernel 2.4.2, but we
> noticed that according to free, our memory utilization went way up. Here
> is the output of free on the 2.4.2 machine:
>              total       used       free     shared    buffers     cached
> Mem:        513192     492772      20420          0       1684     263188
> -/+ buffers/cache:     227900     285292
> Swap:       819304        540     818764
> 
> 
> On the 2.2..18 machine:
>              total       used       free     shared    buffers     cached
> Mem:        517256     351280     165976      19920      82820     186836
> -/+ buffers/cache:      81624     435632
> Swap:       819304          0     819304
> 
> 
> Doing the math, the 2.4 machine is using 44% of available memory, while
> the 2.2 is using only about 14%.

What does /proc/slabinfo report for the number of pages locked down in
the inode and dentry caches? My machine has pretty much every inode in
memory and is using close to 50% of my memory for these (214MB/512MB).

These caches do not seem to be counted towards 'reclaimable' memory by
the new VM and are only pruned when _all_ other attempts to free up
memory have failed.

This becomes very noticeable on a not very fast, small memory machine
(i.e. 48MB sparc-IPC), where 2.2 stays relatively snappy, but 2.4
becomes unusable after an updatedb run.

Jan


  parent reply	other threads:[~2001-03-20 18:55 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-03-19  2:07 /proc/cpuinfo for Intel P4 D850GB asenec
2001-03-19  2:33 ` davej
2001-03-19  3:14 ` 2.4.3-pre4: Unable to handle kernel NULL pointer dereference at virtual address 000000fb Shawn Starr
2001-03-19 12:02 ` /proc/cpuinfo for Intel P4 D850GB David Weinehall
2001-03-19 21:58 ` 2.4.3-pre4: Unable to handle kernel NULL pointer dereference at virtual address 000000fb Shawn Starr
2001-03-20 17:01 ` Question about memory usage in 2.4 vs 2.2 Josh Grebe
2001-03-20 17:32   ` Jakob Østergaard
2001-03-20 20:29     ` Josh Grebe
2001-03-21 19:16       ` Jan Harkes
2001-03-21 19:54         ` Rik van Riel
2001-03-20 18:54   ` Jan Harkes [this message]
2001-03-20 20:29     ` Josh Grebe
2001-03-20 22:18       ` Rik van Riel
2001-03-20 22:29         ` Juha Saarinen
2001-03-21  9:28         ` Zou Min
2001-03-21  9:51           ` Andreas Dilger
2001-03-21 10:56             ` Zou Min
  -- strict thread matches above, loose matches on Subject: below --
2001-03-21 10:14 Manfred Spraul
2001-03-21 17:42 ` Josh Grebe

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