From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263185AbTJZOwV (ORCPT ); Sun, 26 Oct 2003 09:52:21 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263190AbTJZOwV (ORCPT ); Sun, 26 Oct 2003 09:52:21 -0500 Received: from mx1.redhat.com ([66.187.233.31]:22790 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S263185AbTJZOwT (ORCPT ); Sun, 26 Oct 2003 09:52:19 -0500 Date: Sun, 26 Oct 2003 14:51:56 +0000 From: Dave Jones To: Pavel Machek Cc: "Luck, Tony" , Bjorn Helgaas , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, marcelo@conectiva.com.br Subject: Re: [PATCH 2.4.23-pre8] Remove broken prefetching in free_one_pgd() Message-ID: <20031026145156.GB28572@redhat.com> Mail-Followup-To: Dave Jones , Pavel Machek , "Luck, Tony" , Bjorn Helgaas , linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, marcelo@conectiva.com.br References: <20031025201010.GC505@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20031025201010.GC505@elf.ucw.cz> User-Agent: Mutt/1.5.4i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Oct 25, 2003 at 10:10:10PM +0200, Pavel Machek wrote: > > This patch was accepted into 2.5.55, attributed to "davej@uk". > Dave Jones?n Yep. > > This code will prefetch from beyond the end of the page table > > being cleared ... which is clearly a bad thing if the page table > > in question is allocated from the last page of memory (or precedes > > a hole on a discontig mem system). > Prefetching random addresses should be safe... It isn't on some CPUs. Early athlons go bang when you prefetch past the end of RAM into unmapped memory for eg. Dave -- Dave Jones http://www.codemonkey.org.uk