top swap interpretation help?

[Dave Stevens]

On Monday 30 March 2009 09:54:54 pm Robert Nichols wrote:
> Dave Stevens wrote:
> > current example:
> >
> > top - 16:14:05 up 10 days, 43 min,  1 user,  load average: 0.04, 0.13,
> > 0.16 Tasks: 197 total,   3 running, 194 sleeping,   0 stopped,   0 zombie
> > Cpu(s):  5.3%us,  4.1%sy,  0.2%ni, 90.0%id,  0.0%wa,  0.3%hi,  0.0%si, 
> > 0.0%st Mem:   4129236k total,  3817620k used,   311616k free,   332628k
> > buffers Swap:  2031608k total,       84k used,  2031524k free,  1446812k
> > cached
> >
> > So this shows 2 gigs of swap with 84K used. Fine, But it doesn't show the
> > 84K in use right after boot time and in fact only shows up after there's
> > been some especially heavy use of the machine. But it seems to be a kind
> > of high-water mark. When the level of machine use goes down, even way
> > down, the swap still shows as being in use and at the same level. I find
> > this counter-intuitive and think I may be misunderstanding the figure.
>
> It's the amount currently in use.  What you are seeing in swap are those
> pages that got written once when you booted and logged in and were never
> referenced again, thus no reason to bring them back in from swap.  You
> can run "swapoff -a; swapon -a" to force them back in, but eventually
> those same pages are going to end up in swap again, even with little
> memory pressure.

Thank you. Much obliged.

D

>
> --
> Bob Nichols     "NOSPAM" is really part of my email address.
>                  Do NOT delete it.



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