On Wed, Apr 11, 2012 at 08:45:33PM -0400, Rik van Riel wrote: > On 04/11/2012 06:00 PM, Ying Han wrote: > >1. If soft_limit are all set to MAX, it wastes first three periority iterations > >without scanning anything. > > > >2. By default every memcg is eligibal for softlimit reclaim, and we can also > >set the value to MAX for special memcg which is immune to soft limit reclaim. > > > >This idea is based on discussion with Michal and Johannes from LSF. > > Combined with patch 2/5, would this not result in always > returning "reclaim from this memcg" for groups without a > configured softlimit, while groups with a configured > softlimit only get reclaimed from when they are over > their limit? > > Is that the desired behaviour when a system has some > cgroups with a configured softlimit, and some without? Yes, in general I think this new behaviour is welcome. In the past, soft limits were only used to give excess memory a lower priority and there was no particular meaning associated with "being below your soft limit". This change makes it so that soft limits are actually a minimum guarantee, too, so you wouldn't get reclaimed if you behaved (if possible): A-unconfigured B-below-softlimit old: reclaim reclaim new: reclaim no reclaim (if possible) The much less obvious change here, however, is that we no longer put extra pressure on groups above their limit compared to unconfigured groups: A-unconfigured B-above-softlimit old: reclaim reclaim twice new: reclaim reclaim I still think that it's a reasonable use case to put a soft limit on a workload to "nice" it memory-wise, without looking at the machine as a whole and configuring EVERY cgroup based on global knowledge and static partitioning of the machine. -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>