On Thu 12-04-12 04:22:33, Johannes Weiner wrote: > 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 Agreed and I guess that the above should be a part of the changelog. This is changing previous behavior and we should rather be explicit about that. > 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. -- Michal Hocko SUSE Labs SUSE LINUX s.r.o. Lihovarska 1060/12 190 00 Praha 9 Czech Republic -- 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>