Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755941Ab1FNKFF (ORCPT ); Tue, 14 Jun 2011 06:05:05 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36741 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755908Ab1FNKFB (ORCPT ); Tue, 14 Jun 2011 06:05:01 -0400 Date: Tue, 14 Jun 2011 12:04:12 +0200 From: Johannes Weiner To: KAMEZAWA Hiroyuki 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 Subject: Re: [BUGFIX][PATCH 5/5] memcg: fix percpu cached charge draining frequency Message-ID: <20110614100412.GE6371@redhat.com> References: <20110613120054.3336e997.kamezawa.hiroyu@jp.fujitsu.com> <20110613121648.3d28afcd.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110613121648.3d28afcd.kamezawa.hiroyu@jp.fujitsu.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2595 Lines: 71 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. > @@ -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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/