Messages in this thread Patch in this message | | | Date | Wed, 27 Nov 2013 19:20:37 -0800 (PST) | From | David Rientjes <> | Subject | Re: [merged] mm-memcg-handle-non-error-oom-situations-more-gracefully.patch removed from -mm tree |
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On Wed, 27 Nov 2013, Johannes Weiner wrote:
> > It appears as though this work is being developed in Linus's tree rather > > than -mm, so I'm asking if we should consider backing some of it out for > > 3.14 instead. > > The changes fix a deadlock problem. Are they creating problems that > are worse than deadlocks, that would justify their revert? >
None that I am currently aware of, I'll continue to try them out. I'd suggest just dropping the stable@kernel.org from the whole series though unless there is another report of such a problem that people are running into.
> Since we can't physically draw a perfect line, we should strive for a > reasonable and intuitive line. After that it's rapidly diminishing > returns. Killing something after that much reclaim effort without > success is a completely reasonable and intuitive line to draw. It's > also the line that has been drawn a long time ago and we're not > breaking this because of a micro optmimization. >
You don't think something like this is helpful after scanning a memcg will a large number of processes?
We've had this patch internally since we started using memcg, it has avoided some unnecessary oom killing. --- diff --git a/mm/memcontrol.c b/mm/memcontrol.c --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1836,6 +1836,13 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask, if (!chosen) return; points = chosen_points * 1000 / totalpages; + + /* One last chance to see if we really need to kill something */ + if (mem_cgroup_margin(memcg) >= (1 << order)) { + put_task_struct(chosen); + return; + } + oom_kill_process(chosen, gfp_mask, order, points, totalpages, memcg, NULL, "Memory cgroup out of memory"); }
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