On Tue, 15 Jun 2010 20:29:49 -0400 Rik van Riel <riel@xxxxxxxxxx> wrote: > On 06/15/2010 08:17 PM, KAMEZAWA Hiroyuki wrote: > > On Tue, 15 Jun 2010 15:16:01 +0100 > > Mel Gorman<mel@xxxxxxxxx> wrote: > > >> But in turn, where is mem_cgroup_hierarchical_reclaim called from direct > >> reclaim? It appears to be only called from the fault path or as a result > >> of the memcg changing size. > >> > > yes. It's only called from > > - page fault > > - add_to_page_cache() > > > > I think we'll see no stack problem. Now, memcg doesn't wakeup kswapd for > > reclaiming memory, it needs direct writeback. > > Of course, a memcg page fault could still be triggered > from copy_to_user or copy_from_user, with a fairly > arbitrary stack frame above... > Hmm. But I don't expect copy_from/to_user is called in very deep stack. Should I prepare a thread for reclaiming memcg pages ? Because we shouldn't limit kswapd's cpu time by CFS cgroup, waking up kswapd just because "a memcg hit limits" isn't fun. Hmm, or do you recommend no-dirty-page-writeback when a memcg hits limit ? Maybe we'll see much swaps. I want to go with this for a while, changing memcg's behavior will took some amounts of time, there are only a few developpers. Thanks, -Kame -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>