Re: [PATCH][RFC] memory.min_usage again

[yamamoto@valinux.co.jp (YAMAMOTO Takashi)]

hi,

> On Wed, 10 Sep 2008 08:32:15 -0700
> Balbir Singh <balbir@linux.vnet.ibm.com> wrote:
> 
> > YAMAMOTO Takashi wrote:
> > > hi,
> > > 
> > >> hi,
> > >>
> > >> here's a patch to implement memory.min_usage,
> > >> which controls the minimum memory usage for a cgroup.
> > >>
> > >> it works similarly to mlock;
> > >> global memory reclamation doesn't reclaim memory from
> > >> cgroups whose memory usage is below the value.
> > >> setting it too high is a dangerous operation.
> > >>
> > 
> > Looking through the code I am a little worried, what if every cgroup is below
> > minimum value and the system is under memory pressure, do we OOM, while we could
> > have easily reclaimed?

i'm not sure what you are worring about.  can you explain a little more?
under the configuration, OOM is an expected behaviour.

> > 
> > I would prefer to see some heuristics around such a feature, mostly around the
> > priority that do_try_to_free_pages() to determine how desperate we are for
> > reclaiming memory.
> > 
> Taking "priority" of memory reclaim path into account is good.
> 
> ==
> static unsigned long shrink_inactive_list(unsigned long max_scan,
>                         struct zone *zone, struct scan_control *sc,
>                         int priority, int file)
> ==
> How about ignore min_usage if "priority < DEF_PRIORITY - 2" ?

are you suggesting ignoring mlock etc as well in that case?

YAMAMOTO Takashi

> 
> 
> Thanks,
> -Kame
> 
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