On Tue, 1 Aug 2017, Roman Gushchin wrote: > > To the rest of the patch. I have to say I do not quite like how it is > > implemented. I was hoping for something much simpler which would hook > > into oom_evaluate_task. If a task belongs to a memcg with kill-all flag > > then we would update the cumulative memcg badness (more specifically the > > badness of the topmost parent with kill-all flag). Memcg will then > > compete with existing self contained tasks (oom_badness will have to > > tell whether points belong to a task or a memcg to allow the caller to > > deal with it). But it shouldn't be much more complex than that. > > I'm not sure, it will be any simpler. Basically I'm doing the same: > the difference is that you want to iterate over tasks and for each > task traverse the memcg tree, update per-cgroup oom score and find > the corresponding memcg(s) with the kill-all flag. I'm doing the opposite: > traverse the cgroup tree, and for each leaf cgroup iterate over processes. > > Also, please note, that even without the kill-all flag the decision is made > on per-cgroup level (except tasks in the root cgroup). > I think your implementation is preferred and is actually quite simple to follow, and I would encourage you to follow through with it. It has a similar implementation to what we have done for years to kill a process from a leaf memcg. I did notice that oom_kill_memcg_victim() calls directly into __oom_kill_process(), however, so we lack the traditional oom killer output that shows memcg usage and potential tasklist. I think we should still be dumping this information to the kernel log so that we can see a breakdown of charged memory. -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
