From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262363AbTE2RCD (ORCPT ); Thu, 29 May 2003 13:02:03 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262402AbTE2RCC (ORCPT ); Thu, 29 May 2003 13:02:02 -0400 Received: from mail-in-01.arcor-online.net ([151.189.21.41]:54433 "EHLO mail-in-01.arcor-online.net") by vger.kernel.org with ESMTP id S262363AbTE2RCB (ORCPT ); Thu, 29 May 2003 13:02:01 -0400 From: Daniel Phillips To: Hugh Dickins , "Paul E. McKenney" Subject: Re: [RFC][PATCH] Avoid vmtruncate/mmap-page-fault race Date: Thu, 29 May 2003 19:15:22 +0200 User-Agent: KMail/1.5.1 Cc: , , , References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200305291915.22235.phillips@arcor.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 29 May 2003 18:33, you wrote: > On Thu, 29 May 2003, Paul E. McKenney wrote: > > On Fri, May 23, 2003 at 11:42:02AM -0700, Paul E. McKenney wrote: > > > Exactly -- allows a ->nopage() to drop some lock to avoid races > > > between pagefault and either vmtruncate() or invalidate_mmap_range(). > > > This race (from the cross-host mmap viewpoint) is described in: > > > > > > http://marc.theaimsgroup.com/?l=linux-kernel&m=105286345316249&w=2 > > > > Rediffed for 2.5.70-mm1. > > Me? I much preferred your original, much sparer, nopagedone patch > (labelled "uglyh as hell" by hch). "me too". The fat patch that hits every fs to get rid of two lines and .5 cycles per no_page fault could be an epilogue (if/when it passes muster) to the little one that does the job and has already been thoroughly tested. I see both sides of the argument. The third side, not yet discussed, is the value of doing things incrementally, with widespread testing of the system at each step. Regards, Daniel