On Wed, 17 Aug 2011 13:35:50 +0200 Michal Hocko <mhocko@xxxxxxx> wrote: > 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? > How about (1 << (MAX_ORDER-1))/loop ? Thanks, -Kame -- 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>