top shows '<swapped>'
tom.hurst at clara.net
Wed May 9 16:47:29 UTC 2007
* Bill LeFebvre (bill at lefebvre.org) wrote:
> The <> are only used when the process flag PS_INMEM is clear, which
> is supposed to indicate that the process is or is not "in memory".
> This flag is only ever cleared in swapout, called from swapout_procs.
> My bet is that the processes are being marked for swap but the dirty
> pages never actually go anywhere since you don't have a backing
> store. Maybe someone more familiar with the inner workings of the VM
> system can fill us in on what happens on a system with no swap.
I'm seeing this sort of thing too -- I do have swap, but it's not being
used by these processes (swapoff -a didn't do anything to them):
Mem: 1672M Active, 5337M Inact, 279M Wired, 400M Cache, 215M Buf, 74M Free
Swap: 10G Total, 12K Used, 10G Free
1251 www 1 4 0 87884K 0K accept 2 0:00 0.00% <httpd>
1106 root 1 20 0 12756K 0K pause 1 0:00 0.00% <smbd>
950 root 1 115 0 8536K 0K select 3 0:00 0.00% <pure-ftpd>
1143 mysql 1 8 0 5220K 0K wait 3 0:00 0.00% <sh>
1288 root 1 5 0 3644K 0K ttyin 2 0:00 0.00% <getty>
The bulk of the data is probably "swapped" to the on-disk binaries, but
this would imply there isn't a single page unique to each process.
Quite why it's bothering in the first place with >5GB Inact I'm not
sure -- is it unmapping idle processes to conserve VM objects?
I also find it interesting that I only noticed this behavior a few days
ago and suddenly someone else mentions it too :)
Thomas 'Freaky' Hurst
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