Re: oom: Bogus "sysrq: OOM request ignored because killer is disabled" message

[Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>]

Michal Hocko wrote:
> [Fixup Vladimir email address]
> 
> On Mon 03-04-17 10:38:00, Michal Hocko wrote:
> > On Sun 02-04-17 12:52:55, Tetsuo Handa wrote:
> > > I noticed that SysRq-f prints
> > > 
> > >   "sysrq: OOM request ignored because killer is disabled"
> > > 
> > > when no process was selected (rather than when oom killer was disabled).
> > > This message was not printed until Linux 4.8 because commit 7c5f64f84483bd13
> > > ("mm: oom: deduplicate victim selection code for memcg and global oom") changed
> > >  from "return true;" to "return !!oc->chosen;" when is_sysrq_oom(oc) is true.
> > > 
> > > Is this what we meant?
> > > 
> > > [  713.805315] sysrq: SysRq : Manual OOM execution
> > > [  713.808920] Out of memory: Kill process 4468 ((agetty)) score 0 or sacrifice child
> > > [  713.814913] Killed process 4468 ((agetty)) total-vm:43704kB, anon-rss:1760kB, file-rss:0kB, shmem-rss:0kB
> > > [  714.004805] sysrq: SysRq : Manual OOM execution
> > > [  714.005936] Out of memory: Kill process 4469 (systemd-cgroups) score 0 or sacrifice child
> > > [  714.008117] Killed process 4469 (systemd-cgroups) total-vm:10704kB, anon-rss:120kB, file-rss:0kB, shmem-rss:0kB
> > > [  714.189310] sysrq: SysRq : Manual OOM execution
> > > [  714.193425] sysrq: OOM request ignored because killer is disabled
> > > [  714.381313] sysrq: SysRq : Manual OOM execution
> > > [  714.385158] sysrq: OOM request ignored because killer is disabled
> > > [  714.573320] sysrq: SysRq : Manual OOM execution
> > > [  714.576988] sysrq: OOM request ignored because killer is disabled
> > 
> > So, what about this?

I thought below change in out_of_memory().

-	return !!oc->chosen;
+	return oc->chosen || is_sysrq_oom(oc);

You can take either approach.

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