From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id AC2386B0071 for ; Thu, 10 Jun 2010 21:59:02 -0400 (EDT) Received: from m4.gw.fujitsu.co.jp ([10.0.50.74]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id o5B1x0uB004413 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Fri, 11 Jun 2010 10:59:00 +0900 Received: from smail (m4 [127.0.0.1]) by outgoing.m4.gw.fujitsu.co.jp (Postfix) with ESMTP id D23CD45DE60 for ; Fri, 11 Jun 2010 10:58:59 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (s4.gw.fujitsu.co.jp [10.0.50.94]) by m4.gw.fujitsu.co.jp (Postfix) with ESMTP id B2F3245DE4D for ; Fri, 11 Jun 2010 10:58:59 +0900 (JST) Received: from s4.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 9883B1DB8041 for ; Fri, 11 Jun 2010 10:58:59 +0900 (JST) Received: from m106.s.css.fujitsu.com (m106.s.css.fujitsu.com [10.249.87.106]) by s4.gw.fujitsu.co.jp (Postfix) with ESMTP id 42FA31DB803E for ; Fri, 11 Jun 2010 10:58:59 +0900 (JST) Date: Fri, 11 Jun 2010 10:54:41 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [RFC/T/D][PATCH 2/2] Linux/Guest cooperative unmapped page cache control Message-Id: <20100611105441.ee657515.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <1276214852.6437.1427.camel@nimitz> References: <20100608155140.3749.74418.sendpatchset@L34Z31A.ibm.com> <20100608155153.3749.31669.sendpatchset@L34Z31A.ibm.com> <4C10B3AF.7020908@redhat.com> <20100610142512.GB5191@balbir.in.ibm.com> <1276214852.6437.1427.camel@nimitz> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Dave Hansen Cc: balbir@linux.vnet.ibm.com, Avi Kivity , kvm , linux-mm@kvack.org, linux-kernel@vger.kernel.org List-ID: On Thu, 10 Jun 2010 17:07:32 -0700 Dave Hansen wrote: > On Thu, 2010-06-10 at 19:55 +0530, Balbir Singh wrote: > > > I'm not sure victimizing unmapped cache pages is a good idea. > > > Shouldn't page selection use the LRU for recency information instead > > > of the cost of guest reclaim? Dropping a frequently used unmapped > > > cache page can be more expensive than dropping an unused text page > > > that was loaded as part of some executable's initialization and > > > forgotten. > > > > We victimize the unmapped cache only if it is unused (in LRU order). > > We don't force the issue too much. We also have free slab cache to go > > after. > > Just to be clear, let's say we have a mapped page (say of /sbin/init) > that's been unreferenced since _just_ after the system booted. We also > have an unmapped page cache page of a file often used at runtime, say > one from /etc/resolv.conf or /etc/passwd. > Hmm. I'm not fan of estimating working set size by calculation based on some numbers without considering history or feedback. Can't we use some kind of feedback algorithm as hi-low-watermark, random walk or GA (or somehing more smart) to detect the size ? 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