From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx181.postini.com [74.125.245.181]) by kanga.kvack.org (Postfix) with SMTP id AFC3C6B13F0 for ; Tue, 14 Feb 2012 06:10:13 -0500 (EST) Received: from m2.gw.fujitsu.co.jp (unknown [10.0.50.72]) by fgwmail6.fujitsu.co.jp (Postfix) with ESMTP id D17583EE0BB for ; Tue, 14 Feb 2012 20:10:11 +0900 (JST) Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id B835445DE53 for ; Tue, 14 Feb 2012 20:10:11 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 9792145DE4E for ; Tue, 14 Feb 2012 20:10:11 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 8854C1DB803F for ; Tue, 14 Feb 2012 20:10:11 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.240.81.133]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 308E41DB802C for ; Tue, 14 Feb 2012 20:10:11 +0900 (JST) Date: Tue, 14 Feb 2012 20:08:42 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH 6/6 v4] memcg: fix performance of mem_cgroup_begin_update_page_stat() Message-Id: <20120214200842.df132ab1.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20120214120414.025625c2.kamezawa.hiroyu@jp.fujitsu.com> <20120214121631.782352f2.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: owner-linux-mm@kvack.org List-ID: To: Greg Thelen Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "hannes@cmpxchg.org" , Michal Hocko , "akpm@linux-foundation.org" , Ying Han , Hugh Dickins On Mon, 13 Feb 2012 23:22:50 -0800 Greg Thelen wrote: > On Mon, Feb 13, 2012 at 7:16 PM, KAMEZAWA Hiroyuki > wrote: > > From 3377fd7b6e23a5d2a368c078eae27e2b49c4f4aa Mon Sep 17 00:00:00 2001 > > From: KAMEZAWA Hiroyuki > > Date: Mon, 6 Feb 2012 12:14:47 +0900 > > Subject: [PATCH 6/6] memcg: fix performance of mem_cgroup_begin_update_page_stat() > > > > mem_cgroup_begin_update_page_stat() should be very fast because > > it's called very frequently. Now, it needs to look up page_cgroup > > and its memcg....this is slow. > > > > This patch adds a global variable to check "a memcg is moving or not". > > s/a memcg/any memcg/ > yes. > > By this, the caller doesn't need to visit page_cgroup and memcg. > > s/By/With/ > ok. > > Here is a test result. A test program makes page faults onto a file, > > MAP_SHARED and makes each page's page_mapcount(page) > 1, and free > > the range by madvise() and page fault again. A This program causes > > 26214400 times of page fault onto a file(size was 1G.) and shows > > shows the cost of mem_cgroup_begin_update_page_stat(). > > Out of curiosity, what is the performance of the mmap program before > this series? > Score of 3 runs underlinux-next. == [root@bluextal test]# time ./mmap 1G real 0m21.041s user 0m6.146s sys 0m14.625s [root@bluextal test]# time ./mmap 1G real 0m21.063s user 0m6.019s sys 0m14.776s [root@bluextal test]# time ./mmap 1G real 0m21.178s user 0m6.000s sys 0m14.849s == My program is attached. This program is for checking cost of updating FILE_MAPPED. I guess sys_time scores's error rate will be 0.2-0.3 sec. Thanks, -Kame == #include #include #include #include #include #include #include void reader(int fd, int size) { int i, off, x; char *addr; addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0); for (i = 0; i < 100; i++) { for(off = 0; off < size; off += 4096) { x += *(addr + off); } madvise(addr, size, MADV_DONTNEED); } } int main(int argc, char *argv[]) { int fd; char *addr, *c; unsigned long size; struct stat statbuf; fd = open(argv[1], O_RDONLY); if (fd < 0) { perror("cannot open file"); return 1; } if (fstat(fd, &statbuf)) { perror("fstat failed"); return 1; } size = statbuf.st_size; /* mmap in 2 place. */ addr = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0); mlock(addr, size); reader(fd, size); } -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org