Re: [RFC][PATCH 2/7] RSS controller core

[Kirill Korotaev <dev@sw.ru>]

>>So what to do when virtual physical limit is hit?
>>OOM-kill current task?
> 
> 
> when the RSS limit is hit, but there _are_ enough
> pages left on the physical system, there is no
> good reason to swap out the page at all
> 
>  - there is no benefit in doing so (performance
>    wise, that is)
> 
>  - it actually hurts performance, and could
>    become a separate source for DoS
> 
> what should happen instead (in an ideal world :)
> is that the page is considered swapped out for
> the guest (add guest penality for swapout), and 
> when the page would be swapped in again, the guest
> takes a penalty (for the 'virtual' page in) and
> the page is returned to the guest, possibly kicking
> out (again virtually) a different page

great. I agree with that.
Just curious why current vserver code kills arbitrary
task in container then?


>>> - accounting and limits have to be consistent
>>>   and should roughly represent the actual used
>>>   memory/swap (modulo optimizations, I can go
>>>   into detail here, if necessary)
>>
>>This is true for current implementation for
>>booth - this patchset ang OpenVZ beancounters.
>>
>>If you sum up the physpages values for all containers
>>you'll get the exact number of RAM pages used.
> 
> 
> hmm, including or excluding the host pages?

depends on whether you will include beanocunter 0 usages or not :)

Kirill