On Wed 17-08-11 09:54:05, KAMEZAWA Hiroyuki wrote: > On Thu, 11 Aug 2011 16:50:55 +0200 > Michal Hocko <mhocko@xxxxxxx> wrote: > > > What about this (just compile tested)? > > --- > > From: Michal Hocko <mhocko@xxxxxxx> > > Subject: memcg: add nr_pages argument for hierarchical reclaim > > > > Now that we are doing memcg direct reclaim limited to nr_to_reclaim > > pages (introduced by "memcg: stop vmscan when enough done.") we have to > > be more careful. Currently we are using SWAP_CLUSTER_MAX which is OK for > > most callers but it might cause failures for limit resize or force_empty > > code paths on big NUMA machines. > > > > Previously we might have reclaimed up to nr_nodes * SWAP_CLUSTER_MAX > > while now we have it at SWAP_CLUSTER_MAX. Both resize and force_empty rely > > on reclaiming a certain amount of pages and retrying if their condition is > > still not met. > > > > Let's add nr_pages argument to mem_cgroup_hierarchical_reclaim which will > > push it further to try_to_free_mem_cgroup_pages. We still fall back to > > SWAP_CLUSTER_MAX for small requests so the standard code (hot) paths are not > > affected by this. > > > > Open questions: > > - Should we care about soft limit as well? Currently I am using excess > > number of pages for the parameter so it can replace direct query for > > the value in mem_cgroup_hierarchical_reclaim but should we push it to > > mem_cgroup_shrink_node_zone? > > I do not think so because we should try to reclaim from more groups in the > > hierarchy and also it doesn't get to shrink_zones which has been modified > > by the previous patch. > > > > > - mem_cgroup_force_empty asks for reclaiming all pages. I guess it should be > > OK but will have to think about it some more. > > force_empty/rmdir() is allowed to be stopped by Ctrl-C. I think passing res->usage > is overkilling. So, how many pages should be reclaimed then? > > @@ -2332,7 +2332,8 @@ static int mem_cgroup_do_charge(struct m > > return CHARGE_WOULDBLOCK; > > > > ret = mem_cgroup_hierarchical_reclaim(mem_over_limit, NULL, > > - gfp_mask, flags, NULL); > > + gfp_mask, flags, NULL, > > + nr_pages); > > Hmm, in usual, nr_pages = batch = CHARGE_BATCH = 32 ? At allocating Hugepage, > this nr_pages will be 512 ? I think it's too big... Yes it is. I have posted updated version already: http://www.spinics.net/lists/linux-mm/msg23113.html > > Thanks, > -Kame -- 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>