Re: [PATCH v6 6/9] memcg: add cgroupfs interface to memcg dirtylimits

[KAMEZAWA Hiroyuki]

On Tue, 15 Mar 2011 10:01:05 -0400
Mike Heffner <mike@xxxxxxxxxxx> wrote:

> On 03/11/2011 01:43 PM, Greg Thelen wrote:
> > Add cgroupfs interface to memcg dirty page limits:
> >    Direct write-out is controlled with:
> >    - memory.dirty_ratio
> >    - memory.dirty_limit_in_bytes
> >
> >    Background write-out is controlled with:
> >    - memory.dirty_background_ratio
> >    - memory.dirty_background_limit_bytes
> 
> 
> What's the overlap, if any, with the current memory limits controlled by 
> `memory.limit_in_bytes` and the above `memory.dirty_limit_in_bytes`? If 
> I want to fairly balance memory between two cgroups be one a dirty page 
> antagonist (dd) and the other an anonymous page (memcache), do I just 
> set `memory.limit_in_bytes`? Does this patch simply provide a more 
> granular level of control of the dirty limits?
> 

dirty_ratio is for control
 - speed of write() within cgroup.
 - risk of huge latency at memory reclaim (and OOM)
   Small dirty ratio means big ratio of clean page within cgroup.
   This will make memory reclaim, pageout easier.

memory.limit_in_bytes controls the amount of memory.

Thanks,
-Kame

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