On Thu, 10 Jun 2010 11:34:24 +0900 Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote: > I can't find any trivial bugs from my review at the moment. > I'll do some tests. > Thank you for review. > Some minor commens. > > On Wed, 9 Jun 2010 15:59:40 +0900, KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> wrote: > > Still RFC, added lkml to CC: list. > > == > > From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> > > > > Now, memory cgroup increments css(cgroup subsys state)'s reference > > count per a charged page. And the reference count is kept until > > the page is uncharged. But this has 2 bad effect. > > > > 1. Because css_get/put calls atoimic_inc()/dec, heavy call of them > > on large smp will not scale well. > > 2. Because css's refcnt cannot be in a state as "ready-to-release", > > cgroup's notify_on_release handler can't work with memcg. > > > > This is a trial to remove css's refcnt per a page. Even if we remove > > refcnt, pre_destroy() does enough synchronization. > > > > After this patch, it seems css_get() is still called in try_charge(). > > But the logic is. > > > > 1. task_lock(mm->owner) > There is no task_lock() in this version :) > yes. > (snip) > > @@ -4219,7 +4252,6 @@ static int mem_cgroup_do_precharge(unsig > > mc.precharge += count; > > VM_BUG_ON(test_bit(CSS_ROOT, &mem->css.flags)); > > WARN_ON_ONCE(count > INT_MAX); > > - __css_get(&mem->css, (int)count); > > return ret; > > } > > one_by_one: > You can remove VM_BUG_ON() and WARN_ON_ONCE() here, too. > ok. > > @@ -4469,8 +4501,6 @@ static void mem_cgroup_clear_mc(void) > > */ > > res_counter_uncharge(&mc.to->res, > > PAGE_SIZE * mc.moved_swap); > > - VM_BUG_ON(test_bit(CSS_ROOT, &mc.to->css.flags)); > > - __css_put(&mc.to->css, mc.moved_swap); > > } > > /* we've already done mem_cgroup_get(mc.to) */ > > > > > And, you can remove "WARN_ON_ONCE(mc.moved_swap > INT_MAX)" at the beginning > of this block, too. > Hmm. ok. Ah...them, this patch fixes the limitation by "css's refcnt is int" problem. sounds nice. Thanks, -Kmae -- 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>