I can't find any trivial bugs from my review at the moment. I'll do some tests. 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 :) (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. > @@ -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. Thanks, Daisuke Nishimura. -- 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>