Re: [PATCH] mm,oom: use ALLOC_OOM for OOM victim's last second allocation

[Michal Hocko <mhocko@suse.com>]

On Thu 07-12-17 20:59:34, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > On Thu 07-12-17 20:42:20, Tetsuo Handa wrote:
> > > Manish Jaggi noticed that running LTP oom01/oom02 ltp tests with high core
> > > count causes random kernel panics when an OOM victim which consumed memory
> > > in a way the OOM reaper does not help was selected by the OOM killer [1].
> > > Since commit 696453e66630ad45 ("mm, oom: task_will_free_mem should skip
> > > oom_reaped tasks") changed task_will_free_mem(current) in out_of_memory()
> > > to return false as soon as MMF_OOM_SKIP is set, many threads sharing the
> > > victim's mm were not able to try allocation from memory reserves after the
> > > OOM reaper gave up reclaiming memory.
> > > 
> > > Therefore, this patch allows OOM victims to use ALLOC_OOM watermark for
> > > last second allocation attempt.
> > > 
> > > [1] http://lkml.kernel.org/r/e6c83a26-1d59-4afd-55cf-04e58bdde188@caviumnetworks.com
> > > 
> > > Fixes: 696453e66630ad45 ("mm, oom: task_will_free_mem should skip oom_reaped tasks")
> > > Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
> > > Reported-by: Manish Jaggi <mjaggi@caviumnetworks.com>
> > > Acked-by: Michal Hocko <mhocko@suse.com>
> > 
> > I haven't acked _this_ patch! I will have a look but the patch is
> > different enough from the original that keeping any acks or reviews is
> > inappropriate. Do not do it again!
> 
> I see. But nothing has changed except that this is called before entering
> into the OOM killer. I assumed that this is a trivial change.

Let the reviewers judge and have them add their acks/reviewed-bys again.
-- 
Michal Hocko
SUSE Labs

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