From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753338AbZBZRk2 (ORCPT ); Thu, 26 Feb 2009 12:40:28 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751577AbZBZRkT (ORCPT ); Thu, 26 Feb 2009 12:40:19 -0500 Received: from smtp3.ultrahosting.com ([74.213.175.254]:44283 "EHLO smtp.ultrahosting.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751430AbZBZRkS (ORCPT ); Thu, 26 Feb 2009 12:40:18 -0500 Date: Thu, 26 Feb 2009 12:30:45 -0500 (EST) From: Christoph Lameter X-X-Sender: cl@qirst.com To: Mel Gorman cc: Andrew Morton , linux-mm@kvack.org, penberg@cs.helsinki.fi, riel@redhat.com, kosaki.motohiro@jp.fujitsu.com, hannes@cmpxchg.org, npiggin@suse.de, linux-kernel@vger.kernel.org, ming.m.lin@intel.com, yanmin_zhang@linux.intel.com Subject: Re: [PATCH 20/20] Get rid of the concept of hot/cold page freeing In-Reply-To: <20090226171549.GH32756@csn.ul.ie> Message-ID: References: <1235344649-18265-21-git-send-email-mel@csn.ul.ie> <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> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 26 Feb 2009, Mel Gorman 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? Not often enough to justify the merging of my patches at the time. This was publicly discussed on lkml: http://lkml.indiana.edu/hypermail/linux/kernel/0503.2/0482.html > Indeed, any gain if it existed would be avoiding zeroing the pages used > by userspace. The cleanup would be reducing the amount of > architecture-specific code. > > I reckon it's worth an investigate but there is still other lower-lying > fruit. I hope we can get rid of various ugly elements of the quicklists if the page allocator would offer some sort of support. I would think that the slow allocation and freeing behavior is also a factor that makes quicklists advantageous. The quicklist page lists are simply a linked list of pages and a page can simply be dequeued and used.