Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755770AbZIBFWA (ORCPT ); Wed, 2 Sep 2009 01:22:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755759AbZIBFV7 (ORCPT ); Wed, 2 Sep 2009 01:21:59 -0400 Received: from fgwmail7.fujitsu.co.jp ([192.51.44.37]:51733 "EHLO fgwmail7.fujitsu.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755729AbZIBFV6 (ORCPT ); Wed, 2 Sep 2009 01:21:58 -0400 X-SecurityPolicyCheck-FJ: OK by FujitsuOutboundMailChecker v1.3.1 Date: Wed, 2 Sep 2009 14:20:01 +0900 From: KAMEZAWA Hiroyuki To: Daisuke Nishimura Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "balbir@linux.vnet.ibm.com" , "akpm@linux-foundation.org" Subject: Re: [mmotm][PATCH 2/2] memcg: reduce calls for soft limit excess Message-Id: <20090902142001.35cae908.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090902141639.565175d3.nishimura@mxp.nes.nec.co.jp> References: <20090902093438.eed47a57.kamezawa.hiroyu@jp.fujitsu.com> <20090902093551.c8b171fb.kamezawa.hiroyu@jp.fujitsu.com> <20090902141639.565175d3.nishimura@mxp.nes.nec.co.jp> Organization: FUJITSU Co. 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X-Mailer: Sylpheed 2.5.0 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4905 Lines: 134 On Wed, 2 Sep 2009 14:16:39 +0900 Daisuke Nishimura wrote: > On Wed, 2 Sep 2009 09:35:51 +0900, KAMEZAWA Hiroyuki wrote: > > In charge path, usage_in_excess is calculated repeatedly and > > it takes res_counter's spin_lock every time. > > > Hmm, mem_cgroup_update_tree() is called in both charge and uncharge path. > So, this patch have effect on both path, doesn't it ? > > > This patch removes unnecessary calls for res_count_soft_limit_excess. > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > mm/memcontrol.c | 31 +++++++++++++++---------------- > > 1 file changed, 15 insertions(+), 16 deletions(-) > > > > Index: mmotm-2.6.31-Aug27/mm/memcontrol.c > > =================================================================== > > --- mmotm-2.6.31-Aug27.orig/mm/memcontrol.c > > +++ mmotm-2.6.31-Aug27/mm/memcontrol.c > > @@ -313,7 +313,8 @@ soft_limit_tree_from_page(struct page *p > > static void > > __mem_cgroup_insert_exceeded(struct mem_cgroup *mem, > > struct mem_cgroup_per_zone *mz, > > - struct mem_cgroup_tree_per_zone *mctz) > > + struct mem_cgroup_tree_per_zone *mctz, > > + unsigned long new_usage_in_excess) > It might be a nitpick, shouldn't it be unsigned long long ? > Ouch, yes. I'll post fixed one, today. Thank you for pointing out. -Kame > Otherwise, it looks good to me. > > Reviewed-by: Daisuke Nishimura > > Thanks, > Daisuke Nishimura. > > > { > > struct rb_node **p = &mctz->rb_root.rb_node; > > struct rb_node *parent = NULL; > > @@ -322,7 +323,9 @@ __mem_cgroup_insert_exceeded(struct mem_ > > if (mz->on_tree) > > return; > > > > - mz->usage_in_excess = res_counter_soft_limit_excess(&mem->res); > > + mz->usage_in_excess = new_usage_in_excess; > > + if (!mz->usage_in_excess) > > + return; > > while (*p) { > > parent = *p; > > mz_node = rb_entry(parent, struct mem_cgroup_per_zone, > > @@ -382,7 +385,7 @@ static bool mem_cgroup_soft_limit_check( > > > > static void mem_cgroup_update_tree(struct mem_cgroup *mem, struct page *page) > > { > > - unsigned long long new_usage_in_excess; > > + unsigned long long excess; > > struct mem_cgroup_per_zone *mz; > > struct mem_cgroup_tree_per_zone *mctz; > > int nid = page_to_nid(page); > > @@ -395,25 +398,21 @@ static void mem_cgroup_update_tree(struc > > */ > > for (; mem; mem = parent_mem_cgroup(mem)) { > > mz = mem_cgroup_zoneinfo(mem, nid, zid); > > - new_usage_in_excess = > > - res_counter_soft_limit_excess(&mem->res); > > + excess = res_counter_soft_limit_excess(&mem->res); > > /* > > * We have to update the tree if mz is on RB-tree or > > * mem is over its softlimit. > > */ > > - if (new_usage_in_excess || mz->on_tree) { > > + if (excess || mz->on_tree) { > > spin_lock(&mctz->lock); > > /* if on-tree, remove it */ > > if (mz->on_tree) > > __mem_cgroup_remove_exceeded(mem, mz, mctz); > > /* > > - * if over soft limit, insert again. mz->usage_in_excess > > - * will be updated properly. > > + * Insert again. mz->usage_in_excess will be updated. > > + * If excess is 0, no tree ops. > > */ > > - if (new_usage_in_excess) > > - __mem_cgroup_insert_exceeded(mem, mz, mctz); > > - else > > - mz->usage_in_excess = 0; > > + __mem_cgroup_insert_exceeded(mem, mz, mctz, excess); > > spin_unlock(&mctz->lock); > > } > > } > > @@ -2216,6 +2215,7 @@ unsigned long mem_cgroup_soft_limit_recl > > unsigned long reclaimed; > > int loop = 0; > > struct mem_cgroup_tree_per_zone *mctz; > > + unsigned long long excess; > > > > if (order > 0) > > return 0; > > @@ -2260,9 +2260,8 @@ unsigned long mem_cgroup_soft_limit_recl > > __mem_cgroup_largest_soft_limit_node(mctz); > > } while (next_mz == mz); > > } > > - mz->usage_in_excess = > > - res_counter_soft_limit_excess(&mz->mem->res); > > __mem_cgroup_remove_exceeded(mz->mem, mz, mctz); > > + excess = res_counter_soft_limit_excess(&mz->mem->res); > > /* > > * One school of thought says that we should not add > > * back the node to the tree if reclaim returns 0. > > @@ -2271,8 +2270,8 @@ unsigned long mem_cgroup_soft_limit_recl > > * memory to reclaim from. Consider this as a longer > > * term TODO. > > */ > > - if (mz->usage_in_excess) > > - __mem_cgroup_insert_exceeded(mz->mem, mz, mctz); > > + /* If excess == 0, no tree ops */ > > + __mem_cgroup_insert_exceeded(mz->mem, mz, mctz, excess); > > spin_unlock(&mctz->lock); > > css_put(&mz->mem->css); > > loop++; > > > -- 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/