[PLUG] Massive buffer cache yet still swapping

Terry Griffin griffint at pobox.com
Wed Sep 3 12:53:02 UTC 2003


On Wed, Sep 03, 2003 at 11:17:42AM -0700, Steve Bonds wrote:
> I've recently run into a performance problem on my desktop where the
> system swaps out things that I'd rather stay in memory (i.e. the Mozilla
> session I was using 10 minutes ago, desktops I haven't visited for a
> while, etc.)  All the while, I see a massive buffer cache taking up space
> that could be used for the programs I'm about to use again.
> 
> A search of the Usual Spots (google) hasn't turned up much:
> 
> http://www.google.com/search?q=linux+buffer+cache+limits
> 
> This guy seems to have the same problem I do:
>   + http://mail.nl.linux.org/linux-mm/2001-04/msg00010.html
> 
> but I never saw any solution posted.
> 
> Even in 1999 it looked like the documented /proc/sys/vm values didn't
> work:
>   + http://mail.nl.linux.org/linux-mm-www/1999-12/msg00000.html
> 
> Here's what /proc/meminfo shows me:
> 
> -----
>         total:    used:    free:  shared: buffers:  cached:
> Mem:  517677056 510160896  7516160        0 35762176 363266048
> Swap: 534634496 131747840 402886656
> MemTotal:       505544 kB
> MemFree:          7340 kB
> MemShared:           0 kB
> Buffers:         34924 kB
> Cached:         327292 kB
> SwapCached:      27460 kB
> Active:         378056 kB
> ActiveAnon:     171064 kB
> ActiveCache:    206992 kB
> Inact_dirty:      6064 kB
> Inact_laundry:   67784 kB
> Inact_clean:      8820 kB
> Inact_target:    92144 kB
> HighTotal:           0 kB
> HighFree:            0 kB
> LowTotal:       505544 kB
> LowFree:          7340 kB
> SwapTotal:      522104 kB
> SwapFree:       393444 kB
> -----
> 
> The problem is the Cached: line seems very high.  The next step is some
> kernel-diving, but it would be great if one of you knows of a good way to
> tune this.
> 
>   -- Steve
> 
> 

What kernel version is this? And is it a stock kernel from kernel.org or
a patched kernel from a distributor?

Terry
-- 
Terry Griffin <griffint at pobox.com>
http://www.blindchicken.com/~terryg/




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