Re: Swappiness vs. mmap() and interactive response

KOSAKI Motohiro
2009-04-28T07:44:44Z

> On Tue, Apr 28, 2009 at 03:52:29PM +0900, KOSAKI Motohiro wrote:
> > Hi
> >
> > > 3. cache limitation of memcgroup solve this problem?
> > >
> > > I was unable to get this to work -- do you have some documentation handy?
> >
> > Do you have kernel source tarball?
> > Documentation/cgroups/memory.txt explain usage kindly.
>
> Thank you. My documentation was out of date.
>
> I created a cgroup with limited memory and placed a copy command in it, and the
> latency problem seems to essentially go away. However, I'm also a bit
> suspicious that my test might have become invalid, since my IO performance
> seems to have dropped somewhat too.
>
> So, am I right in concluding that this more or less implicates bad page
> replacement as the culprit? After I dropped vm caches and let my working set
> re-form, the memory cgroup seems to be effective at keeping a large pool of
> memory free from file pressure.

Hmm..
it seems your result mean bad page replacement occur. but actually
I hevn't seen such result on my environment.

Hmm, I think I need to make reproduce environmet to your trouble.

Thanks.