From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992897AbXCICri (ORCPT ); Thu, 8 Mar 2007 21:47:38 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S2992900AbXCICrh (ORCPT ); Thu, 8 Mar 2007 21:47:37 -0500 Received: from ozlabs.org ([203.10.76.45]:44576 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992897AbXCICrg (ORCPT ); Thu, 8 Mar 2007 21:47:36 -0500 Date: Thu, 8 Mar 2007 20:46:06 -0600 From: Anton Blanchard To: Linus Torvalds Cc: Eric Dumazet , Davide Libenzi , Avi Kivity , Linux Kernel Mailing List , Andrew Morton , Al Viro Subject: Re: [patch] epoll use a single inode ... Message-ID: <20070309024606.GB24695@kryten> References: <45ED1A3C.6030707@argo.co.il> <200703071906.58405.dada1@cosmosbay.com> <200703071952.13219.dada1@cosmosbay.com> <20070307221401.GA16938@kryten> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.12-2006-07-14 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org > Yeah, I'm not at all surprised. Any implementation of "prefetch" that > doesn't just turn into a no-op if the TLB entry doesn't exist (which makes > them weaker for *actual* prefetching) will generally have a hard time with > a NULL pointer. Exactly because it will try to do a totally unnecessary > TLB fill - and since most CPU's will not cache negative TLB entries, that > unnecessary TLB fill will be done over and over and over again.. Yeah this is exactly what we were seeing :) Anton