From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail6.bemta7.messagelabs.com (mail6.bemta7.messagelabs.com [216.82.255.55]) by kanga.kvack.org (Postfix) with ESMTP id D14BA6B0012 for ; Tue, 14 Jun 2011 20:23:56 -0400 (EDT) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id 950203EE0C7 for ; Wed, 15 Jun 2011 09:23:52 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 76F6745DE69 for ; Wed, 15 Jun 2011 09:23:52 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 5620B45DD6E for ; Wed, 15 Jun 2011 09:23:52 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 477911DB802C for ; Wed, 15 Jun 2011 09:23:52 +0900 (JST) Received: from ml14.s.css.fujitsu.com (ml14.s.css.fujitsu.com [10.240.81.134]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 01B371DB803C for ; Wed, 15 Jun 2011 09:23:52 +0900 (JST) Date: Wed, 15 Jun 2011 09:16:52 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [BUGFIX][PATCH 5/5] memcg: fix percpu cached charge draining frequency Message-Id: <20110615091652.7d29baca.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20110614100412.GE6371@redhat.com> References: <20110613120054.3336e997.kamezawa.hiroyu@jp.fujitsu.com> <20110613121648.3d28afcd.kamezawa.hiroyu@jp.fujitsu.com> <20110614100412.GE6371@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Johannes Weiner Cc: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "akpm@linux-foundation.org" , "nishimura@mxp.nes.nec.co.jp" , "bsingharora@gmail.com" , "hannes@cmpxchg.org" , Michal Hocko , Ying Han On Tue, 14 Jun 2011 12:04:12 +0200 Johannes Weiner wrote: > On Mon, Jun 13, 2011 at 12:16:48PM +0900, KAMEZAWA Hiroyuki wrote: > > @@ -1670,8 +1670,8 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, > > victim = mem_cgroup_select_victim(root_mem); > > if (victim == root_mem) { > > loop++; > > - if (loop >= 1) > > - drain_all_stock_async(); > > + if (!check_soft && loop >= 1) > > + drain_all_stock_async(root_mem); > > I agree with Michal, this should be a separate change. > Hm, ok, I'll do. > > @@ -2008,26 +2011,50 @@ static void refill_stock(struct mem_cgroup *mem, unsigned int nr_pages) > > * expects some charges will be back to res_counter later but cannot wait for > > * it. > > */ > > -static void drain_all_stock_async(void) > > +static void drain_all_stock_async(struct mem_cgroup *root_mem) > > { > > - int cpu; > > - /* This function is for scheduling "drain" in asynchronous way. > > - * The result of "drain" is not directly handled by callers. Then, > > - * if someone is calling drain, we don't have to call drain more. > > - * Anyway, WORK_STRUCT_PENDING check in queue_work_on() will catch if > > - * there is a race. We just do loose check here. > > + int cpu, curcpu; > > + /* > > + * If someone calls draining, avoid adding more kworker runs. > > */ > > - if (atomic_read(&memcg_drain_count)) > > + if (!mutex_trylock(&percpu_charge_mutex)) > > return; > > /* Notify other cpus that system-wide "drain" is running */ > > - atomic_inc(&memcg_drain_count); > > get_online_cpus(); > > + > > + /* > > + * get a hint for avoiding draining charges on the current cpu, > > + * which must be exhausted by our charging. But this is not > > + * required to be a precise check, We use raw_smp_processor_id() > > + * instead of getcpu()/putcpu(). > > + */ > > + curcpu = raw_smp_processor_id(); > > for_each_online_cpu(cpu) { > > struct memcg_stock_pcp *stock = &per_cpu(memcg_stock, cpu); > > - schedule_work_on(cpu, &stock->work); > > + struct mem_cgroup *mem; > > + > > + if (cpu == curcpu) > > + continue; > > + > > + mem = stock->cached; > > + if (!mem) > > + continue; > > + if (mem != root_mem) { > > + if (!root_mem->use_hierarchy) > > + continue; > > + /* check whether "mem" is under tree of "root_mem" */ > > + rcu_read_lock(); > > + if (!css_is_ancestor(&mem->css, &root_mem->css)) { > > + rcu_read_unlock(); > > + continue; > > + } > > + rcu_read_unlock(); > > css_is_ancestor() takes the rcu read lock itself already. > you're right. I'll post an update. Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org