[Lxc-users] total RAM limit

[Frederic Crozat]

Le lundi 04 février 2013 à 08:38 -0600, Serge Hallyn a écrit :
> Quoting Gary Ballantyne (gary.ballantyne at haulashore.com):
> > On Fri, 1 Feb 2013 10:24:13 -0600
> > Serge Hallyn <serge.hallyn at canonical.com> wrote:
> > 
> > > 
> > > Did you actually test with a memory hog program? I just noticed there
> > > appears to be a bug in that if I
> > > 
> > > 	d=/sys/fs/cgroup/memory/a
> > > 	mkdir $d
> > > 	echo 1 > $d/memory.use_hierarchy
> > > 	echo 5000 > $d/memory.limit_in_bytes
> > > 	mkdir $d/b
> > > 
> > > then $d/b/memory.limit_in_bytes does not report the reduced limit.  However
> > > whenI run a program which does char *c = malloc(10000) after doing
> > > 	echo $$ > $d/b/tasks
> > > 
> > > then I get killed by OOM.
> > > 
> > > -serge
> > 
> > I tested with a large array in ipython. Though, from your example, it seems I'm missing memory.use_hierarchy.
> > 
> > In principle, it seems like I need something like:
> > 
> > echo 1 > /sys/fs/cgroup/memory/lxc/memory.use_hierarchy
> > 
> > But, I can't do that before the container is started (no lxc directory) or after it is started (device busy).
> > 
> 
> Yup, it looks like lxc ought to set that at startup.  I can think of
> absolutely no cases where we would *not* want that done.  Something
> like:
> 
> Subject: [PATCH 1/1] Try to enable memory cgroup use_hierarchy option.
> 
> The memory cgroup has a 'memory.use_hierarchy' which is initialized to
> 0.  It needs to be set to 1 at our top level, that is
> /sys/fs/cgroup/memory/lxc/memory.use_hiararchy, before we create any
> containers.  After the fact is too late.
> 
> Signed-off-by: Serge Hallyn <serge.hallyn at ubuntu.com>

Any reason this patch was not pushed ?

After fixing it a bit (it was missing some directory creation and needed some massage), it works as expected on 0.8.0 
and it prevents kernel warning about memcgroup use_hierarchy warning. 

New version (for 0.8.0) attached.


-- 
Frederic Crozat <fcrozat at suse.com>
SUSE

-- 
Frederic Crozat <fcrozat at suse.com>
SUSE
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