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@xxxxxxxxxxx> 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@xxxxxxxxx>
To: Hedi Boufaied <hedi.boufaied@xxxxxxxxxxx>,
Cc: kernelnewbies <kernelnewbies@xxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxx> 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
>
> ---
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