From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932969AbXCMIDq (ORCPT ); Tue, 13 Mar 2007 04:03:46 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933012AbXCMIDp (ORCPT ); Tue, 13 Mar 2007 04:03:45 -0400 Received: from smtp102.plus.mail.mud.yahoo.com ([68.142.206.235]:30415 "HELO smtp102.plus.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932969AbXCMIDn (ORCPT ); Tue, 13 Mar 2007 04:03:43 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:X-YMail-OSG:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=eVFfY3J0NO59itk63gEawfhELUvRsmr3fROSWhqfM2uxqgb8TYQhV55+s0ZnDXn3rRRyR+lfSPQhS4mvSO7QvOTW/PiXlUo4UKFpjVZuNSExgN8c6m5FCkFXoyiq6I7+0FpXqy9zlo409AhieUD5dgMMlRbSFZKn25D4/cWxuSc= ; X-YMail-OSG: ulgcqfsVM1k63A5cPJzVYhCUSh9mQb1Nbv2pdmDVEqNh_JsMA.FnFEJthtt54YzDR0N_RG7Q0u3tdQMMIRo9K7S6a7v5MyDwUqu1voA3uAJT_X.ONC657LvvNfPcxjDIknJnH_mMhmJUmI9hHPMHJs9loQ-- Message-ID: <45F65ADA.9010501@yahoo.com.au> Date: Tue, 13 Mar 2007 19:03:38 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Andrew Morton CC: Christoph Lameter , linux-mm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [QUICKLIST 0/4] Arch independent quicklists V2 References: <20070313071325.4920.82870.sendpatchset@schroedinger.engr.sgi.com> <20070313005334.853559ca.akpm@linux-foundation.org> In-Reply-To: <20070313005334.853559ca.akpm@linux-foundation.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton wrote: >>On Tue, 13 Mar 2007 00:13:25 -0700 (PDT) Christoph Lameter wrote: >>Page table pages have the characteristics that they are typically zero >>or in a known state when they are freed. > > > Well if they're zero then perhaps they should be released to the page allocator > to satisfy the next __GFP_ZERO request. If that request is for a pagetable > page, we break even (except we get to remove special-case code). If that > __GFP_ZERO allocation was or some application other than for a pagetable, we > win. > > iow, can we just nuke 'em? Page allocator still requires interrupts to be disabled, which this doesn't. Considering there isn't much else that frees known zeroed pages, I wonder if it is worthwhile. Last time the zeroidle discussion came up was IIRC not actually real performance gain, just cooking the 1024 CPU threaded pagefault numbers ;) -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com