From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Fri, 4 Jul 2008 09:47:14 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC][-mm] [3/7] add shmem page to active list. Message-Id: <20080704094714.ea41ac9d.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: References: <20080702210322.518f6c43.kamezawa.hiroyu@jp.fujitsu.com> <20080702211057.7a7cf3dc.kamezawa.hiroyu@jp.fujitsu.com> <20080703091144.93465ba5.kamezawa.hiroyu@jp.fujitsu.com> <20080703132730.b64dcd19.kamezawa.hiroyu@jp.fujitsu.com> <20080703164320.1087f758.kamezawa.hiroyu@jp.fujitsu.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Hugh Dickins Cc: "linux-mm@kvack.org" , "balbir@linux.vnet.ibm.com" , "xemul@openvz.org" , "nishimura@mxp.nes.nec.co.jp" , "yamamoto@valinux.co.jp" , "kosaki.motohiro@jp.fujitsu.com" List-ID: On Thu, 3 Jul 2008 23:28:21 +0100 (BST) Hugh Dickins wrote: > On Thu, 3 Jul 2008, KAMEZAWA Hiroyuki wrote: > > On Thu, 3 Jul 2008 08:03:17 +0100 (BST) > > Hugh Dickins wrote: > > > > > On Thu, 3 Jul 2008, KAMEZAWA Hiroyuki wrote: > > > > > > > > BTW, is there a way to see the RSS usage of shmem from /proc or somewhere ? > > > > > > No, it's just been a (very weirdly backed!) filesystem until these > > > -mm developments. If you add such stats (for more than temporary > > > debugging), you'll need to use per_cpu counters for it: more global > > > locking or atomic ops on those paths would be sure to upset SGI. > > > > like zone stat ? > > Like that, yes. I had been going to suggest adding another couple > of stats to that (one for in memory, one for on swap, or heading > to or from swap); but noticed that everything there is an event, > with the comment "Counters should only be incremented", so it > would be an abuse to add shmem page counts there. > Thank you for all your advices. It seems there is no another way rather than using zone_stat. I'll try it first and see what happens. (It uses per-cpu counter and update global counter when it goes over threshold.) BTW, measuring performance of file copy on tmpfs is enough to see overhead ? Thanks, -Kame -- 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