On Thu 22-10-15 00:21:35, Johannes Weiner wrote: > The vmpressure metric is based on reclaim efficiency, which in turn is > an attribute of the LRU. However, vmpressure events are currently > reported at the source of pressure rather than at the reclaim level. > > Switch the reporting to the reclaim level to allow finer-grained > analysis of which memcg is having trouble reclaiming its pages. I can see how this can be useful. > As far as memory.pressure_level interface semantics go, events are > escalated up the hierarchy until a listener is found, so this won't > affect existing users that listen at higher levels. This is true but the parent will not see cumulative events anymore. One memcg might be fighting and barely reclaim anything so it would report high pressure while other would be doing just fine. The parent will just see conflicting events in a short time period and cannot match them the source memcg. This sounds really confusing. Even more confusing than the current semantic which allows the same behavior under certain configurations. I dunno, have to think about it some more. Maybe we need to rethink the way how the pressure is signaled. If we want the breakdown of the particular memcgs then we should be able to identify them for this to be useful. [...] -- 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>