On Thu, Oct 05, 2017 at 04:31:04PM +0200, Michal Hocko wrote: > Btw. here is how I would do the recursive oom badness. The diff is not > the nicest one because there is some code moving but the resulting code > is smaller and imho easier to grasp. Only compile tested though Thanks! I'm not against this approach, and maybe it can lead to a better code, but the version you sent is just not there yet. There are some problems with it: 1) If there are nested cgroups with oom_group set, you will calculate a badness multiple times, and rely on the fact, that top memcg will become the largest score. It can be optimized, of course, but it's additional code. 2) cgroup_has_tasks() probably requires additional locking. Maybe it's ok to read nr_populated_csets without explicit locking, but it's not obvious for me. 3) Returning -1 from memcg_oom_badness() if eligible is equal to 0 is suspicious. Right now your version has exactly the same amount of code (skipping comments). I assume, this approach just requires some additional thinking/rework. Anyway, thank you for sharing this! > --- > diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h > index 085056e562b1..9cdba4682198 100644 > --- a/include/linux/cgroup.h > +++ b/include/linux/cgroup.h > @@ -122,6 +122,11 @@ void cgroup_free(struct task_struct *p); > int cgroup_init_early(void); > int cgroup_init(void); > > +static bool cgroup_has_tasks(struct cgroup *cgrp) > +{ > + return cgrp->nr_populated_csets; > +} > + > /* > * Iteration helpers and macros. > */ > diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c > index 8dacf73ad57e..a2dd7e3ffe23 100644 > --- a/kernel/cgroup/cgroup.c > +++ b/kernel/cgroup/cgroup.c > @@ -319,11 +319,6 @@ static void cgroup_idr_remove(struct idr *idr, int id) > spin_unlock_bh(&cgroup_idr_lock); > } > > -static bool cgroup_has_tasks(struct cgroup *cgrp) > -{ > - return cgrp->nr_populated_csets; > -} > - > bool cgroup_is_threaded(struct cgroup *cgrp) > { > return cgrp->dom_cgrp != cgrp; -- 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