On Tue, Apr 22, 2014 at 6:34 PM, Michal Hocko <mhocko@xxxxxxx> wrote: > Sorry, I should have been more specific that I was talking about > mem_cgroup_reclaim_cookie path where the iteration for this particular > zone and priority ended at the last node without finishing the full > roundtrip last time. This new iteration (prev==NULL) wants to continue > and it should start a new roundtrip. > > Makes sense? Hi, Michal, Good catch, it makes sense ! This reminds me of my draft edition of this patch, I specifically handle this case as: if (reclaim) { if (!memcg ) { iter->generation++; if (!prev) { memcg = root; mem_cgroup_iter_update(iter, NULL, memcg, root, seq); goto out_unlock: } } mem_cgroup_iter_update(iter, last_visited, memcg, root, seq); if (!prev && memcg) reclaim->generation = iter->generation; } This is literally manual unwinding the second while loop, and thus omit the while loop, to save a mem_cgroup_iter_update() and a mem_cgroup_iter_update() But it maybe a bit hard to read. If it is OK, I could resend a new one. Thanks, Jianyu Zhan -- 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>