From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with SMTP id 6F6E16B00D7 for ; Wed, 25 Feb 2009 02:09:08 -0500 (EST) Message-ID: <49A4EEA0.3010309@cn.fujitsu.com> Date: Wed, 25 Feb 2009 15:09:20 +0800 From: Li Zefan MIME-Version: 1.0 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: owner-linux-mm@kvack.org 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" List-ID: > 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) -- 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/ . Don't email: email@kvack.org