Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755737AbZIBFSq (ORCPT ); Wed, 2 Sep 2009 01:18:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755661AbZIBFSq (ORCPT ); Wed, 2 Sep 2009 01:18:46 -0400 Received: from TYO201.gate.nec.co.jp ([202.32.8.193]:38281 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755185AbZIBFSp (ORCPT ); Wed, 2 Sep 2009 01:18:45 -0400 Date: Wed, 2 Sep 2009 14:16:39 +0900 From: Daisuke Nishimura To: KAMEZAWA Hiroyuki Cc: nishimura@mxp.nes.nec.co.jp, "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: <20090902141639.565175d3.nishimura@mxp.nes.nec.co.jp> In-Reply-To: <20090902093551.c8b171fb.kamezawa.hiroyu@jp.fujitsu.com> References: <20090902093438.eed47a57.kamezawa.hiroyu@jp.fujitsu.com> <20090902093551.c8b171fb.kamezawa.hiroyu@jp.fujitsu.com> Organization: NEC Soft, Ltd. X-Mailer: Sylpheed 2.6.0 (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: 4498 Lines: 124 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 ? 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/