On Thu 15-06-17 15:03:17, David Rientjes wrote: > On Thu, 15 Jun 2017, Michal Hocko wrote: > > > > Yes, quite a bit in testing. > > > > > > One oom kill shows the system to be oom: > > > > > > [22999.488705] Node 0 Normal free:90484kB min:90500kB ... > > > [22999.488711] Node 1 Normal free:91536kB min:91948kB ... > > > > > > followed up by one or more unnecessary oom kills showing the oom killer > > > racing with memory freeing of the victim: > > > > > > [22999.510329] Node 0 Normal free:229588kB min:90500kB ... > > > [22999.510334] Node 1 Normal free:600036kB min:91948kB ... > > > > > > The patch is absolutely required for us to prevent continuous oom killing > > > of processes after a single process has been oom killed and its memory is > > > in the process of being freed. > > > > OK, could you play with the patch/idea suggested in > > http://lkml.kernel.org/r/20170615122031.gl1...@dhcp22.suse.cz? > > > > I cannot, I am trying to unblock a stable kernel release to my production > that is obviously fixed with this patch and cannot experiment with > uncompiled and untested patches that introduce otherwise unnecessary > locking into the __mmput() path and is based on speculation rather than > hard data that __mmput() for some reason stalls for the oom victim's mm. > I was hoping that this fix could make it in time for 4.12 since 4.12 kills > 1-4 processes unnecessarily for each oom condition and then can review any > tested solution you may propose at a later time.
I am sorry but I have really hard to make the oom reaper a reliable way to stop all the potential oom lockups go away. I do not want to reintroduce another potential lockup now. I also do not see why any solution should be rushed into. I have proposed a way to go and unless it is clear that this is not a way forward then I simply do not agree with any partial workarounds or shortcuts. -- Michal Hocko SUSE Labs
