On Tue, Aug 08, 2017 at 04:06:38PM -0700, David Rientjes wrote: > 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. Hi David! Thank you for the support. > > 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. I think the existing output is too verbose for the case, when we kill a cgroup with many processes inside. But I absolutely agree, that we need some debug output, I'll add it in v5. Thanks! -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
