On Tue 31-07-12 13:59:35, Ying Han wrote: [...] > Let's say the following example where the cgroup is sorted by css_id, > and none of the cgroup's usage is above softlimit (except root) > > root a b c d e f ...max > thread_1 (priority = 12) ^ > iter->position = 1 ( > over_softlimit = true ) > > ^ > iter->position = 2 > > thread_2 (priority = 12) ^ > iter->position = 3 > > .... > ^ > > iter->position = 0 ( over_softlimit = false ) > > In this case, thread 1 gets root but not thread 2 since they share the > walk under same zone (same node) and same reclaim priority. That is true iterator is per zone per priority if the cookie is used but that wasn't my point. Take a much simpler case. Just the background reclaim without any direct reclaim. Then there is nobody to race with and so we would always visit the whole tree including the root and so if no group is above the soft limit we would hammer the root cgroup until priority gets down when we ignore the limit and reclaim from all. Makes sense? -- 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>