Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754915AbZDPMEU (ORCPT ); Thu, 16 Apr 2009 08:04:20 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754336AbZDPMEG (ORCPT ); Thu, 16 Apr 2009 08:04:06 -0400 Received: from e28smtp07.in.ibm.com ([59.145.155.7]:54693 "EHLO e28smtp07.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753693AbZDPMEF (ORCPT ); Thu, 16 Apr 2009 08:04:05 -0400 Date: Thu, 16 Apr 2009 17:33:16 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Andrew Morton Subject: Re: [PATCH] Add file based RSS accounting for memory resource controller (v2) Message-ID: <20090416120316.GG7082@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20090415120510.GX7082@balbir.in.ibm.com> <20090416095303.b4106e9f.kamezawa.hiroyu@jp.fujitsu.com> <20090416015955.GB7082@balbir.in.ibm.com> <20090416110246.c3fef293.kamezawa.hiroyu@jp.fujitsu.com> <20090416164036.03d7347a.kamezawa.hiroyu@jp.fujitsu.com> <20090416171535.cfc4ca84.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20090416171535.cfc4ca84.kamezawa.hiroyu@jp.fujitsu.com> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7819 Lines: 260 * KAMEZAWA Hiroyuki [2009-04-16 17:15:35]: > > > Sorry, some troubles found. Ignore above Ack. 3points now. > > > > 1. get_cpu should be after (*) > > ==mem_cgroup_update_mapped_file_stat() > > + int cpu = get_cpu(); > > + > > + if (!page_is_file_cache(page)) > > + return; > > + > > + if (unlikely(!mm)) > > + mm = &init_mm; > > + > > + mem = try_get_mem_cgroup_from_mm(mm); > > + if (!mem) > > + return; > > + ----------------------------------------(*) > > + stat = &mem->stat; > > + cpustat = &stat->cpustat[cpu]; > > + > > + __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, val); > > + put_cpu(); > > +} > > == Yes or I should have a goto > > > > 2. In above, "mem" shouldn't be got from "mm"....please get "mem" from page_cgroup. > > (Because it's file cache, pc->mem_cgroup is not NULL always.) Hmmm.. not sure I understand this part. Are you suggesting that mm can be NULL? I added the check for !mm as a safety check. Since this routine is only called from rmap context, mm is not NULL, hence mem should not be NULL. Did you find a race between mm->owner assignment and lookup via mm->owner? > > > > I saw this very easily. > > == > > Cache: 4096 > > mapped_file: 20480 > > == > > > > 3. at force_empty(). > > == > > + > > + cpu = get_cpu(); > > + /* Update mapped_file data for mem_cgroup "from" */ > > + stat = &from->stat; > > + cpustat = &stat->cpustat[cpu]; > > + __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, -1); > > + > > + /* Update mapped_file data for mem_cgroup "to" */ > > + stat = &to->stat; > > + cpustat = &stat->cpustat[cpu]; > > + __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, 1); > > + put_cpu(); > > > > This just breaks counter when page is not mapped. please check page_mapped(). > > > > like this: > > == > > if (page_is_file_cache(page) && page_mapped(page)) { > > modify counter. > > } > Oh! yeah.. > == > > > > and call lock_page_cgroup() in mem_cgroup_update_mapped_file_stat(). > > > > This will be slow, but optimization will be very tricky and need some amount of time. > > > > This is my fix for above 3 problems. but plz do as you like. > I'm not very intersted in details. > == > > --- > Index: mmotm-2.6.30-Apr14/mm/memcontrol.c > =================================================================== > --- mmotm-2.6.30-Apr14.orig/mm/memcontrol.c > +++ mmotm-2.6.30-Apr14/mm/memcontrol.c > @@ -322,33 +322,39 @@ static bool mem_cgroup_is_obsolete(struc > return css_is_removed(&mem->css); > } > > -/* > - * Currently used to update mapped file statistics, but the routine can be > - * generalized to update other statistics as well. > - */ > -void mem_cgroup_update_mapped_file_stat(struct page *page, struct mm_struct *mm, > - int val) > +void mem_cgroup_update_mapped_file_stat(struct page *page, bool map) > { > struct mem_cgroup *mem; > struct mem_cgroup_stat *stat; > struct mem_cgroup_stat_cpu *cpustat; > - int cpu = get_cpu(); > + struct page_cgroup *pc; > + int cpu; > > if (!page_is_file_cache(page)) > return; > > - if (unlikely(!mm)) > - mm = &init_mm; > - > - mem = try_get_mem_cgroup_from_mm(mm); > - if (!mem) > + pc = lookup_page_cgroup(page); > + if (unlikely(!pc)) > return; > - > - stat = &mem->stat; > - cpustat = &stat->cpustat[cpu]; > - > - __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, val); > - put_cpu(); > + lock_page_cgroup(pc); > + mem = pc->mem_cgroup; > + if (mem) { > + cpu = get_cpu(); > + stat = &mem->stat; > + cpustat = &stat->cpustat[cpu]; > + if (map) > + __mem_cgroup_stat_add_safe(cpustat, > + MEM_CGROUP_STAT_MAPPED_FILE, 1); > + else > + __mem_cgroup_stat_add_safe(cpustat, > + MEM_CGROUP_STAT_MAPPED_FILE, -1); > + put_cpu(); > + } > + if (map) > + SetPageCgroupMapped(pc); > + else > + ClearPageCgroupMapped(pc); > + unlock_page_cgroup(pc); > } > > /* > @@ -1149,17 +1155,19 @@ static int mem_cgroup_move_account(struc > res_counter_uncharge(&from->res, PAGE_SIZE); > mem_cgroup_charge_statistics(from, pc, false); > > - cpu = get_cpu(); > - /* Update mapped_file data for mem_cgroup "from" */ > - stat = &from->stat; > - cpustat = &stat->cpustat[cpu]; > - __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, -1); > - > - /* Update mapped_file data for mem_cgroup "to" */ > - stat = &to->stat; > - cpustat = &stat->cpustat[cpu]; > - __mem_cgroup_stat_add_safe(cpustat, MEM_CGROUP_STAT_MAPPED_FILE, 1); > - put_cpu(); > + if (PageCgroupMapped(pc)) { > + cpu = get_cpu(); > + /* Update mapped_file data for mem_cgroup "from" and "to" */ > + stat = &from->stat; > + cpustat = &stat->cpustat[cpu]; > + __mem_cgroup_stat_add_safe(cpustat, > + MEM_CGROUP_STAT_MAPPED_FILE, -1); > + stat = &to->stat; > + cpustat = &stat->cpustat[cpu]; > + __mem_cgroup_stat_add_safe(cpustat, > + MEM_CGROUP_STAT_MAPPED_FILE, 1); > + put_cpu(); > + } > > if (do_swap_account) > res_counter_uncharge(&from->memsw, PAGE_SIZE); > Index: mmotm-2.6.30-Apr14/include/linux/page_cgroup.h > =================================================================== > --- mmotm-2.6.30-Apr14.orig/include/linux/page_cgroup.h > +++ mmotm-2.6.30-Apr14/include/linux/page_cgroup.h > @@ -26,6 +26,7 @@ enum { > PCG_LOCK, /* page cgroup is locked */ > PCG_CACHE, /* charged as cache */ > PCG_USED, /* this object is in use. */ > + PCG_MAPPED, /* mapped file cache */ > }; > > #define TESTPCGFLAG(uname, lname) \ > @@ -46,6 +47,10 @@ TESTPCGFLAG(Cache, CACHE) > TESTPCGFLAG(Used, USED) > CLEARPCGFLAG(Used, USED) > > +TESTPCGFLAG(Mapped, USED) > +CLEARPCGFLAG(Mapped, USED) > +SETPCGFLAG(Mapped, USED) > + > static inline int page_cgroup_nid(struct page_cgroup *pc) > { > return page_to_nid(pc->page); > Index: mmotm-2.6.30-Apr14/include/linux/memcontrol.h > =================================================================== > --- mmotm-2.6.30-Apr14.orig/include/linux/memcontrol.h > +++ mmotm-2.6.30-Apr14/include/linux/memcontrol.h > @@ -116,8 +116,7 @@ static inline bool mem_cgroup_disabled(v > } > > extern bool mem_cgroup_oom_called(struct task_struct *task); > -void mem_cgroup_update_mapped_file_stat(struct page *page, struct mm_struct *mm, > - int val); > +void mem_cgroup_update_mapped_file_stat(struct page *page, bool map); > #else /* CONFIG_CGROUP_MEM_RES_CTLR */ > struct mem_cgroup; > > @@ -266,8 +265,7 @@ mem_cgroup_print_oom_info(struct mem_cgr > } > > static inline void mem_cgroup_update_mapped_file_stat(struct page *page, > - struct mm_struct *mm, > - int val) > + bool map) > { > } > > Index: mmotm-2.6.30-Apr14/mm/rmap.c > =================================================================== > --- mmotm-2.6.30-Apr14.orig/mm/rmap.c > +++ mmotm-2.6.30-Apr14/mm/rmap.c > @@ -690,7 +690,7 @@ void page_add_file_rmap(struct page *pag > { > if (atomic_inc_and_test(&page->_mapcount)) { > __inc_zone_page_state(page, NR_FILE_MAPPED); > - mem_cgroup_update_mapped_file_stat(page, vma->vm_mm, 1); > + mem_cgroup_update_mapped_file_stat(page, true); > } > } > > @@ -740,7 +740,7 @@ void page_remove_rmap(struct page *page, > mem_cgroup_uncharge_page(page); > __dec_zone_page_state(page, > PageAnon(page) ? NR_ANON_PAGES : NR_FILE_MAPPED); > - mem_cgroup_update_mapped_file_stat(page, vma->vm_mm, -1); > + mem_cgroup_update_mapped_file_stat(page, false); > /* > * It would be tidy to reset the PageAnon mapping here, > * but that might overwrite a racing page_add_anon_rmap > > > > > > -- Balbir -- 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/