Messages in this thread | | | Date | Thu, 26 Mar 2015 17:07:42 +0100 | From | Michal Hocko <> | Subject | Re: [patch 06/12] mm: oom_kill: simplify OOM killer locking |
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On Thu 26-03-15 11:17:46, Johannes Weiner wrote: > On Thu, Mar 26, 2015 at 02:31:11PM +0100, Michal Hocko wrote: [...] > > > @@ -795,27 +728,21 @@ bool out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, > > > */ > > > void pagefault_out_of_memory(void) > > > { > > > - struct zonelist *zonelist; > > > - > > > - down_read(&oom_sem); > > > if (mem_cgroup_oom_synchronize(true)) > > > - goto unlock; > > > + return; > > > > OK, so we are back to what David has asked previously. We do not need > > the lock for memcg and oom_killer_disabled because we know that no tasks > > (except for potential oom victim) are lurking around at the time > > oom_killer_disable() is called. So I guess we want to stick a comment > > into mem_cgroup_oom_synchronize before we check for oom_killer_disabled. > > I would prefer everybody that sets TIF_MEMDIE and kills a task to hold > the lock, including memcg. Simplicity is one thing, but also a global > OOM kill might not even be necessary when it's racing with the memcg.
sure I am find with that.
> > After those are fixed, feel free to add > > Acked-by: Michal Hocko <mhocko@suse.cz> > > Thanks.
-- Michal Hocko SUSE Labs
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