From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id C30108D0039 for ; Mon, 31 Jan 2011 04:03:54 -0500 (EST) Received: from d23relay05.au.ibm.com (d23relay05.au.ibm.com [202.81.31.247]) by e23smtp02.au.ibm.com (8.14.4/8.13.1) with ESMTP id p0V8waUj002231 for ; Mon, 31 Jan 2011 19:58:36 +1100 Received: from d23av02.au.ibm.com (d23av02.au.ibm.com [9.190.235.138]) by d23relay05.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p0V93f9C2547728 for ; Mon, 31 Jan 2011 20:03:42 +1100 Received: from d23av02.au.ibm.com (loopback [127.0.0.1]) by d23av02.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p0V93eej016162 for ; Mon, 31 Jan 2011 20:03:40 +1100 Date: Mon, 31 Jan 2011 10:07:08 +0530 From: Balbir Singh Subject: Re: [PATCH 3/3] Provide control over unmapped pages (v4) Message-ID: <20110131043708.GF5054@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <20110125051003.13762.35120.stgit@localhost6.localdomain6> <20110125051015.13762.13429.stgit@localhost6.localdomain6> <20110128064851.GB5054@balbir.in.ibm.com> <20110128165605.3cbe5208.kamezawa.hiroyu@jp.fujitsu.com> <20110131085853.b09aef2d.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20110131085853.b09aef2d.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Christoph Lameter , Minchan Kim , linux-mm@kvack.org, akpm@linux-foundation.org, npiggin@kernel.dk, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, kosaki.motohiro@jp.fujitsu.com List-ID: * KAMEZAWA Hiroyuki [2011-01-31 08:58:53]: > On Fri, 28 Jan 2011 09:20:02 -0600 (CST) > Christoph Lameter wrote: > > > On Fri, 28 Jan 2011, KAMEZAWA Hiroyuki wrote: > > > > > > > I see it as a tradeoff of when to check? add_to_page_cache or when we > > > > > are want more free memory (due to allocation). It is OK to wakeup > > > > > kswapd while allocating memory, somehow for this purpose (global page > > > > > cache), add_to_page_cache or add_to_page_cache_locked does not seem > > > > > the right place to hook into. I'd be open to comments/suggestions > > > > > though from others as well. > > > > > > I don't like add hook here. > > > AND I don't want to run kswapd because 'kswapd' has been a sign as > > > there are memory shortage. (reusing code is ok.) > > > > > > How about adding new daemon ? Recently, khugepaged, ksmd works for > > > managing memory. Adding one more daemon for special purpose is not > > > very bad, I think. Then, you can do > > > - wake up without hook > > > - throttle its work. > > > - balance the whole system rather than zone. > > > I think per-node balance is enough... > > > > > > I think we already have enough kernel daemons floating around. They are > > multiplying in an amazing way. What would be useful is to map all > > the memory management background stuff into a process. May call this memd > > instead? Perhaps we can fold khugepaged into kswapd as well etc. > > > > Making kswapd slow for whis "additional", "requested by user, not by system" > work is good thing ? I think workqueue works enough well, it's scale based on > workloads, if using thread is bad. > Making it slow is a generic statement, kswapd is supposed to do background reclaim, in this case a special request for unmapped pages, specifically and deliberately requested by the admin via a boot option. -- Three Cheers, Balbir -- 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 policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org