On Thu, 20 Jan 2011 14:41:08 +0100 Johannes Weiner <hannes@xxxxxxxxxxx> wrote: > 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? > charge_size != page_size. Clean up as you like, later. I'll Ack. > > @@ -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? > That's my mistake of comment, which was in the older patch. I use compound_lock now. I'll post clean up. > I think we need the compound lock to get a stable read, like > compound_trans_order() does. > Thanks, -Kame > 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>