From: Herbert Poetzl (herbert_at_13thfloor.at)
Date: Fri 16 Jul 2004 - 14:43:24 BST
On Fri, Jul 16, 2004 at 03:03:10PM +0200, Gebhardt Thomas wrote:
> I'm trying to understand the output of vserver-stat (from vserver 0.29),
> namely the value of VSZ.
> The manual page says: VSZ=Number of pages of virtual memory
> Well, actually VSZ is not a number of pages but something that is
> counted in bytes. I got suspicious when I noticed that one of my
> vservers actually had VSZ=3GB while the total system has only
> 1GB RAM + 1 GB swap space.
which is quite normal ...
> It seems that VmSize is computed by adding the vm size
> of all processes running within a specific vserver:
> list->VmSize_total += process->VmSize
> Shared memory is counted multiple times.
that might happen ...
> Does this make sense at all?
yep, it does, but the labeling and the explanations
are wrong alltogether ...
here are some facts:
- the VM is called AS at kernel level for good reason,
because it's not virtual memory but Address Space.
- ps calls it VMZ for whatever reason.
- vserver-stat is legacy compatible in the output, and
jackques decided to label it VMZ but display it in
MB which is just another variation ...
- the AS can be large, sometimes larger than the
RAM + SWAP space even for one process (ask SUN about
- it doesn't make much sense to account address spaces
only once, just because they point to the same data
either in memory or swap ...
- RSS (Resident Set Size) is something completely
different, it's the ammount of data resident in the
system memory (available from RAM) ...
> Cheers, Thomas
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