From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262016AbTJAGsD (ORCPT ); Wed, 1 Oct 2003 02:48:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262018AbTJAGsD (ORCPT ); Wed, 1 Oct 2003 02:48:03 -0400 Received: from ns.suse.de ([195.135.220.2]:59090 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S262016AbTJAGsB (ORCPT ); Wed, 1 Oct 2003 02:48:01 -0400 To: Andrew Morton Cc: jamie@shareable.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] Mutilated form of Andi Kleen's AMD prefetch errata patch References: <7F740D512C7C1046AB53446D3720017304AFCF@scsmsx402.sc.intel.com.suse.lists.linux.kernel> <20031001053833.GB1131@mail.shareable.org.suse.lists.linux.kernel> <20030930224853.15073447.akpm@osdl.org.suse.lists.linux.kernel> <20031001061348.GE1131@mail.shareable.org.suse.lists.linux.kernel> <20030930233258.37ed9f7f.akpm@osdl.org.suse.lists.linux.kernel> From: Andi Kleen Date: 01 Oct 2003 08:47:58 +0200 In-Reply-To: <20030930233258.37ed9f7f.akpm@osdl.org.suse.lists.linux.kernel> Message-ID: User-Agent: Gnus/5.09 (Gnus v5.9.0) Emacs/21.2 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andrew Morton writes: > Looking at Andi's patch, it is also a dead box if the fault happens inside > down_write(mmap_sem). That should be fixed, methinks. The only way to fix all that would be to move the instruction checks early into the fast path. [On a P4 the overhead is 3.7268 vs 3.6594 microseconds for a fault that doesn't hit as measured by lmbench2's lat_sig. This was before the latest changes which added more checking, so the overhead is probably bigger now] -Andi