From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758290AbZBYHJU (ORCPT ); Wed, 25 Feb 2009 02:09:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752093AbZBYHJL (ORCPT ); Wed, 25 Feb 2009 02:09:11 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:60726 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751736AbZBYHJK (ORCPT ); Wed, 25 Feb 2009 02:09:10 -0500 Message-ID: <49A4EEA0.3010309@cn.fujitsu.com> Date: Wed, 25 Feb 2009 15:09:20 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: KAMEZAWA Hiroyuki CC: "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" , "balbir@linux.vnet.ibm.com" , "menage@google.com" , "akpm@linux-foundation.org" Subject: Re: [PATCH] use CSS ID in swap_cgroup for saving memory References: <20090225152617.df4eeb35.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20090225152617.df4eeb35.kamezawa.hiroyu@jp.fujitsu.com> 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 > static inline > -struct mem_cgroup *swap_cgroup_record(swp_entry_t ent, struct mem_cgroup *mem) > +unsigned short swap_cgroup_record(swp_entry_t ent, unsigned short id) > { > return NULL; return 0; > } > > static inline > -struct mem_cgroup *lookup_swap_cgroup(swp_entry_t ent) > +unsigned short lookup_swap_cgroup(swp_entry_t ent) > { > return NULL; return 0; > } > @@ -1265,12 +1286,20 @@ int mem_cgroup_cache_charge(struct page > > if (do_swap_account && !ret && PageSwapCache(page)) { > swp_entry_t ent = {.val = page_private(page)}; > + unsigned short id; > /* avoid double counting */ > - mem = swap_cgroup_record(ent, NULL); > + id = swap_cgroup_record(ent, 0); > + rcu_read_lock(); > + mem = mem_cgroup_lookup(id); > if (mem) { > + /* > + * Recorded ID can be obsolete. We avoid calling > + * css_tryget() > + */ > res_counter_uncharge(&mem->memsw, PAGE_SIZE); > mem_cgroup_put(mem); > } > + rcu_read_unlock(); > } > return ret; > } > @@ -1335,13 +1364,21 @@ void mem_cgroup_commit_charge_swapin(str > */ > if (do_swap_account && PageSwapCache(page)) { > swp_entry_t ent = {.val = page_private(page)}; > + unsigned short id; > struct mem_cgroup *memcg; > - memcg = swap_cgroup_record(ent, NULL); > + > + id = swap_cgroup_record(ent, 0); > + rcu_read_lock(); > + memcg = mem_cgroup_lookup(id); > if (memcg) { > + /* > + * This recorded memcg can be obsolete one. So, avoid > + * calling css_tryget > + */ > res_counter_uncharge(&memcg->memsw, PAGE_SIZE); > mem_cgroup_put(memcg); > } > - > + rcu_read_unlock(); > } > /* add this page(page_cgroup) to the LRU we want. */ > > @@ -1462,7 +1499,7 @@ void mem_cgroup_uncharge_swapcache(struc > MEM_CGROUP_CHARGE_TYPE_SWAPOUT); > /* record memcg information */ > if (do_swap_account && memcg) { > - swap_cgroup_record(ent, memcg); > + swap_cgroup_record(ent, css_id(&memcg->css)); > mem_cgroup_get(memcg); > } > if (memcg) > @@ -1477,15 +1514,22 @@ void mem_cgroup_uncharge_swapcache(struc > void mem_cgroup_uncharge_swap(swp_entry_t ent) > { > struct mem_cgroup *memcg; > + unsigned short id; > > if (!do_swap_account) > return; > > - memcg = swap_cgroup_record(ent, NULL); > + id = swap_cgroup_record(ent, 0); > + rcu_read_lock(); > + memcg = mem_cgroup_lookup(id); > if (memcg) { > + /* > + * This memcg can be obsolete one. We avoid calling css_tryget > + */ > res_counter_uncharge(&memcg->memsw, PAGE_SIZE); > mem_cgroup_put(memcg); > } > + rcu_read_unlock(); can we have a common function for the above 3 pieces of code? > } > #endif > > Index: mmotm-2.6.29-Feb24/mm/page_cgroup.c > =================================================================== > --- mmotm-2.6.29-Feb24.orig/mm/page_cgroup.c > +++ mmotm-2.6.29-Feb24/mm/page_cgroup.c > @@ -290,7 +290,7 @@ struct swap_cgroup_ctrl swap_cgroup_ctrl > * cgroup rather than pointer. > */ this comment should be updated/removed: /* * This 8bytes seems big..maybe we can reduce this when we can use "id" for * cgroup rather than pointer. */ > struct swap_cgroup { > - struct mem_cgroup *val; > + unsigned short id; > }; > #define SC_PER_PAGE (PAGE_SIZE/sizeof(struct swap_cgroup)) > #define SC_POS_MASK (SC_PER_PAGE - 1)