[Users] Questions about privvmpages, vmguarpages and oomguarpages

[Jason Voorhees]

Hi there:

I don't speak English correctly so I hope someone can be able to
understand me enough to help me a bit:

>From the OpenVZ wiki I understand this:

- vmguarpages : Guaranteed memory to VE
- privvmpages : Maximum theoric memory available to VE (real available
memory vmguarpages, right?)
- oomguarpages : Guaranteed memory to VE in out-of-memory situations

I see that privvmpages (barrier) should be greater than vmguarpages
(barrier), right? and according to wiki oomguarpages (barrier) should
be greater than privvmpages to make sure applications won't be killed
when memory is exhausted. Is this correct?

But... when is the barrier of oomguarpages reached? Isn't suposed that
VE won't be able to use more than vmguarpages? And even when
vmguarpages = privvmpages... Isn't suposed that VE won't be able to
use more memory than limit of privvmpages?

I only understand that the amount of memory really used at a moment is
the held field of oomguarpages, and the amount of memory allocated at
a moment is the held field of privvmpages.
Also allocated memory use to be greater than really used memory, right?

But anyway I don't really understand what's the scenario usage of
oomguarpages barrier.
Could somebody give me some explanation about this?

Thanks, bye