On Tue, Jan 18, 2011 at 11:43:48AM +0900, KAMEZAWA Hiroyuki wrote: > > Now, when THP is enabled, memcg's rmdir() function is broken > because move_account() for THP page is not supported. > > This will cause account leak or -EBUSY issue at rmdir(). > This patch fixes the issue by supporting move_account() THP pages. > > Changelog: > - style fix. > - add compound_lock for avoiding races. > > Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > --- > mm/memcontrol.c | 37 ++++++++++++++++++++++++++----------- > 1 file changed, 26 insertions(+), 11 deletions(-) > > Index: mmotm-0107/mm/memcontrol.c > =================================================================== > --- mmotm-0107.orig/mm/memcontrol.c > +++ mmotm-0107/mm/memcontrol.c > @@ -2267,6 +2274,8 @@ static int mem_cgroup_move_parent(struct > struct cgroup *cg = child->css.cgroup; > struct cgroup *pcg = cg->parent; > struct mem_cgroup *parent; > + int charge = PAGE_SIZE; No need to initialize, you assign it unconditionally below. It's also a bit unfortunate that the parameter/variable with this meaning appears under a whole bunch of different names. page_size, charge_size, and now charge. Could you stick with page_size? > @@ -2278,17 +2287,23 @@ static int mem_cgroup_move_parent(struct > goto out; > if (isolate_lru_page(page)) > goto put; > + /* The page is isolated from LRU and we have no race with splitting */ > + charge = PAGE_SIZE << compound_order(page); Why is LRU isolation preventing the splitting? I think we need the compound lock to get a stable read, like compound_trans_order() does. Hannes > parent = mem_cgroup_from_cont(pcg); > - ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, > - PAGE_SIZE); > + ret = __mem_cgroup_try_charge(NULL, gfp_mask, &parent, false, charge); > if (ret || !parent) > goto put_back; > > - ret = mem_cgroup_move_account(pc, child, parent, true); > + if (charge > PAGE_SIZE) > + flags = compound_lock_irqsave(page); > + > + ret = mem_cgroup_move_account(pc, child, parent, true, charge); > if (ret) > - mem_cgroup_cancel_charge(parent, PAGE_SIZE); > + mem_cgroup_cancel_charge(parent, charge); > put_back: > + if (charge > PAGE_SIZE) > + compound_unlock_irqrestore(page, flags); > putback_lru_page(page); > put: > put_page(page); -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>