On Tue 09-08-11 19:07:25, KAMEZAWA Hiroyuki wrote: > On Tue, 9 Aug 2011 12:09:44 +0200 > Michal Hocko <mhocko@xxxxxxx> wrote: > > > On Tue 09-08-11 18:53:13, KAMEZAWA Hiroyuki wrote: > > > On Tue, 9 Aug 2011 11:45:03 +0200 > > > Michal Hocko <mhocko@xxxxxxx> wrote: > > > > > > > On Tue 09-08-11 18:32:16, KAMEZAWA Hiroyuki wrote: > > > > > On Tue, 9 Aug 2011 11:31:50 +0200 > > > > > Michal Hocko <mhocko@xxxxxxx> wrote: > > > > > > > > > > > What do you think about the half backed patch bellow? I didn't manage to > > > > > > test it yet but I guess it should help. I hate asymmetry of drain_lock > > > > > > locking (it is acquired somewhere else than it is released which is > > > > > > not). I will think about a nicer way how to do it. > > > > > > Maybe I should also split the rcu part in a separate patch. > > > > > > > > > > > > What do you think? > > > > > > > > > > > > > > > I'd like to revert 8521fc50 first and consider total design change > > > > > rather than ad-hoc fix. > > > > > > > > Agreed. Revert should go into 3.0 stable as well. Although the global > > > > mutex is buggy we have that behavior for a long time without any reports. > > > > We should address it but it can wait for 3.2. > > > > I will send the revert request to Linus. > > > > > What "buggy" means here ? "problematic" or "cause OOps ?" > > > > I have described that in an earlier email. Consider pathological case > > when CPU0 wants to async. drain a memcg which has a lot of cached charges while > > CPU1 is already draining so it holds the mutex. CPU0 backs off so it has > > to reclaim although we could prevent from it by getting rid of cached > > charges. This is not critical though. > > > > That problem should be fixed by background reclaim. How? Do you plan to rework locking or the charge caching completely? -- 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>