Re: inux-next: Tree for Apr 27 (uml + mm/memcontrol.c)

[Hiroyuki Kamezawa]

On Fri, May 4, 2012 at 6:57 AM, David Rientjes <rientjes@xxxxxxxxxx> wrote:
> On Thu, 3 May 2012, David Rientjes wrote:
>
>> Is this a claim that memory-intensive workloads will have the exact same
>> performance with and without memcg enabled?
>
> I've just run specjbb2005 three times on my system both with and without
> cgroup_disable=memory on the command line and it is consistently 1% faster
> without memcg.
Hm, ok. Where is that overheads from ? Do you have perf output ?
I'll need to check what is bad.

> If I add XX:+UseLargePages to the command line to use
> hugepages it's even larger.  So why must I incur this performance
> degradation if I simply want to control who may mmap hugepages out of the
> global pool?

Is that common use case ? If he wants to do some resource control,
common users will limit usual memory, too. That kinds of too much flexibility
makes cgroup complicated, hard-to-use.

Thanks,
-Kame
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