From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id 455F56B0047 for ; Fri, 27 Feb 2009 06:38:20 -0500 (EST) Date: Fri, 27 Feb 2009 12:38:13 +0100 From: Nick Piggin Subject: Re: [PATCH 20/20] Get rid of the concept of hot/cold page freeing Message-ID: <20090227113813.GB21296@wotan.suse.de> References: <20090223013723.1d8f11c1.akpm@linux-foundation.org> <20090223233030.GA26562@csn.ul.ie> <20090223155313.abd41881.akpm@linux-foundation.org> <20090224115126.GB25151@csn.ul.ie> <20090224160103.df238662.akpm@linux-foundation.org> <20090225160124.GA31915@csn.ul.ie> <20090225081954.8776ba9b.akpm@linux-foundation.org> <20090226163751.GG32756@csn.ul.ie> <20090226171549.GH32756@csn.ul.ie> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090226171549.GH32756@csn.ul.ie> Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: Christoph Lameter , Andrew Morton , linux-mm@kvack.org, penberg@cs.helsinki.fi, riel@redhat.com, kosaki.motohiro@jp.fujitsu.com, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, ming.m.lin@intel.com, yanmin_zhang@linux.intel.com List-ID: On Thu, Feb 26, 2009 at 05:15:49PM +0000, Mel Gorman wrote: > On Thu, Feb 26, 2009 at 12:00:22PM -0500, Christoph Lameter wrote: > > I tried the general use of a pool of zeroed pages back in 2005. Zeroing > > made sense only if the code allocating the page did not immediately touch > > the cachelines of the page. > > Any feeling as to how often this was the case? IMO background zeroing or anything like that is only going to become less attractive. Heat and energy considerations are relatively increasing, so doing speculative work in the kernel is going to become relatively more costly. Especially in this case where you use nontemporal stores or otherwise reduce the efficiency of the CPU caches (and increase activity on bus and memory). -- 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