cgroups: cannot write on file memory.oom_control

[Hedi Boufaied]

Hi Rami,

Thank you for the advice. Yes, I will try using the event handler.

Best Regards,
Hedi



From:   Rami Rosen <roszenrami at gmail.com>
To:     Hedi Boufaied <hedi.boufaied at amadeus.com>, 
Cc:     kernelnewbies <kernelnewbies at kernelnewbies.org>
Date:   18/04/2014 22:38
Subject:        Re: cgroups: cannot write on file memory.oom_control
Sent by:        kernelnewbies-bounces at kernelnewbies.org



Hi Hedi,
Well, you can use disabling oom in conjunction  with event handler. Thus, 
you can free memory by changing memory setting of other cgroups when an 
oom occurs in a specific cgroup, and avoid having an oops in that cgroup.
You can see an example of using event handler in conjunction with 
disabling the oom killer in 
"Namespaces and cgroups in linux", in slides 101/102, see:
http://ramirose.wix.com/ramirosen
A shameless plug - I wrote this presentation of 121 slides about 
namespaces and cgroups.
Regards,
Rami Rosen
בתאריך 17 באפר 2014 11:24, "Hedi Boufaied" <hedi.boufaied at amadeus.com> 
כתב:
Hi Rami, 

Thanks a lot for your sequence. I followed it and it does work. 
I now see my process paused in sleep state instead of getting killed when 
the cgroup reaches OoO. 

This being said: 
* I do not really understand why the use_hierarchy option needs to be 
disabled in order to allow disabling of the oom killer... 
* I'm not sure that disabling the OoO killer is safe/reliable enough: in 
some of the trials I made, I saw other processes (xterms) not part of the 
OoO cgroup getting completely stuck and I had to reboot my machine... 

Best Regards, 
Hedi 



From:        Rami Rosen <roszenrami at gmail.com> 
To:        Hedi Boufaied <hedi.boufaied at amadeus.com>, 
Cc:        kernelnewbies <kernelnewbies at kernelnewbies.org> 
Date:        15/04/2014 15:39 
Subject:        Re: cgroups: cannot write on file memory.oom_control 



Hi, Hedi,

This sequence works for me:

echo 0 >  /sys/fs/cgroup/memory/memory.use_hierarchy

mkdir  /sys/fs/cgroup/memory/0

Then, the following two commands changes the value of oom_kill_disable:

echo 1 >   /sys/fs/cgroup/memory/0/memory.oom_control

echo 0 >   /sys/fs/cgroup/memory/0/memory.oom_control


For more info, please look for the text about enabling/disabling
use_hierarchy in section 6,
http://lxr.free-electrons.com/source/Documentation/cgroups/memory.txt.

Regards,
Rami Rosen
http://ramirose.wix.com/ramirosen



On Mon, Apr 14, 2014 at 12:22 PM, Hedi Boufaied
<hedi.boufaied at amadeus.com> wrote:
> Hi everyone,
>
> I am working with cgroups on OpenSuse (over VirtualBox) and I cannot 
disable
> the OOM killer by writing to the file memory.oom_control:
>
>> echo 1 > memory.oom_control
>> -bash: echo: write error: Invalid argument
>
> I can change the memory limit and several other settings by writing to 
the
> appropriate files (like memory.limit_in_bytes) but I could never write 
to
> file memory.oom_control although I am root.
>
> I saw someone posted a similar issue a few days ago but there was no
> reply...
>
> I have copied below the sequence of command I am using. Any idea what 
could
> be the issue ?
>
> Thanks in advance for your help!
>
> Hedi
>
>
> ----
>
> /sys/fs> su - root
>
> /sys/fs> cd cgroup
>
> /sys/fs/cgroup> cgcreate -g memory:/mygroup
>
> /sys/fs/cgroup> cd memory/mygroup
>
> /sys/fs/cgroup/memory/mygroup> echo 32M > memory.limit_in_bytes
>
> /sys/fs/cgroup/memory/mygroup> cat memory.limit_in_bytes
> 33554432
>
> /sys/fs/cgroup/memory/mygroup> echo 1 > memory.oom_control
> -bash: echo: write error: Invalid argument
>
> /sys/fs/cgroup/memory/mygroup> cat memory.oom_control
> oom_kill_disable 0
> under_oom 0
>
> ---
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
>
_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20140422/d0c196f1/attachment.html