On Mon 25-09-17 19:15:33, Roman Gushchin wrote: [...] > I'm not against this model, as I've said before. It feels logical, > and will work fine in most cases. > > In this case we can drop any mount/boot options, because it preserves > the existing behavior in the default configuration. A big advantage.
I am not sure about this. We still need an opt-in, ragardless, because selecting the largest process from the largest memcg != selecting the largest task (just consider memcgs with many processes example). > The only thing, I'm slightly concerned, that due to the way how we calculate > the memory footprint for tasks and memory cgroups, we will have a number > of weird edge cases. For instance, when putting a single process into > the group_oom memcg will alter the oom_score significantly and result > in significantly different chances to be killed. An obvious example will > be a task with oom_score_adj set to any non-extreme (other than 0 and -1000) > value, but it can also happen in case of constrained alloc, for instance. I am not sure I understand. Are you talking about root memcg comparing to other memcgs? -- Michal Hocko SUSE Labs