On Thu, Aug 22, 2019 at 5:19 PM Michal Hocko <mhocko@xxxxxxxx> wrote: > > On Thu 22-08-19 04:56:29, Yafang Shao wrote: > > - Why we need a per memcg oom_score_adj setting ? > > This is easy to deploy and very convenient for container. > > When we use container, we always treat memcg as a whole, if we have a per > > memcg oom_score_adj setting we don't need to set it process by process. > > Why cannot an initial process in the cgroup set the oom_score_adj and > other processes just inherit it from there? This sounds trivial to do > with a startup script. > That is what we used to do before. But it can't apply to the running containers. > > It will make the user exhausted to set it to all processes in a memcg. > > Then let's have scripts to set it as they are less prone to exhaustion > ;) That is not easy to deploy it to the production environment. > But seriously > > > In this patch, a file named memory.oom.score_adj is introduced. > > The valid value of it is from -1000 to +1000, which is same with > > process-level oom_score_adj. > > When OOM is invoked, the effective oom_score_adj is as bellow, > > effective oom_score_adj = original oom_score_adj + memory.oom.score_adj > > This doesn't make any sense to me. Say that process has oom_score_adj > -1000 (never kill) then group oom_score_adj will simply break the > expectation and the task becomes killable for any value but -1000. > Why is summing up those values even sensible? > Ah, good catch. This needs to be improved. > > The valid effective value is also from -1000 to +1000. > > This is something like a hook to re-calculate the oom_score_adj. > > Besides that. What is the hierarchical semantic? Say you have hierarchy > A (oom_score_adj = 1000) > \ > B (oom_score_adj = 500) > \ > C (oom_score_adj = -1000) > > put the above summing up aside for now and just focus on the memcg > adjusting? I think that there's no conflict between children's oom_score_adj, that is different with memory.max. So it is not neccessary to consider the parent's oom_sore_adj. Thanks Yafang
