On Wed 12-12-12 10:09:43, Ying Han wrote: [...] > But If i look at the callers of mem_cgroup_iter(), they all look like > the following: > > memcg = mem_cgroup_iter(root, NULL, &reclaim); > do { > > // do something > > memcg = mem_cgroup_iter(root, memcg, &reclaim); > } while (memcg); > > So we get out of the loop when memcg returns as NULL, where the > last_visited is cached as NULL as well thus no css_get(). That is what > I meant by "each reclaim thread closes the loop". OK > If that is true, the current implementation of mem_cgroup_iter_break() > changes that. I do not understand this though. Why should we touch the zone-iter there? Just consider, if we did that then all the parallel targeted reclaimers (! global case) would hammer the first node (root) as they wouldn't continue where the last one finished. [...] Thanks! -- Michal Hocko SUSE Labs -- 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>