On Tue 03-05-11 16:45:23, KOSAKI Motohiro wrote: > 2011/5/3 Michal Hocko <mhocko@xxxxxxx>: > > On Sun 01-05-11 15:06:02, KOSAKI Motohiro wrote: > >> > On Mon 25-04-11 18:28:49, KAMEZAWA Hiroyuki wrote: > >> > > There are two watermarks added per-memcg including "high_wmark" and "low_wmark". > >> > > The per-memcg kswapd is invoked when the memcg's memory usage(usage_in_bytes) > >> > > is higher than the low_wmark. Then the kswapd thread starts to reclaim pages > >> > > until the usage is lower than the high_wmark. > >> > > >> > I have mentioned this during Ying's patchsets already, but do we really > >> > want to have this confusing naming? High and low watermarks have > >> > opposite semantic for zones. > >> > >> Can you please clarify this? I feel it is not opposite semantics. > > > > In the global reclaim low watermark represents the point when we _start_ > > background reclaim while high watermark is the _stopper_. Watermarks are > > based on the free memory while this proposal makes it based on the used > > memory. > > I understand that the result is same in the end but it is really > > confusing because you have to switch your mindset from free to used and > > from under the limit to above the limit. > > Ah, right. So, do you have an alternative idea? Why cannot we just keep the global reclaim semantic and make it free memory (hard_limit - usage_in_bytes) based with low limit as the trigger for reclaiming? -- 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@xxxxxxxxxx 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>