From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757063AbZBWUoo (ORCPT ); Mon, 23 Feb 2009 15:44:44 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752095AbZBWUod (ORCPT ); Mon, 23 Feb 2009 15:44:33 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:55486 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751630AbZBWUoc (ORCPT ); Mon, 23 Feb 2009 15:44:32 -0500 Date: Mon, 23 Feb 2009 12:44:29 -0800 From: "Paul E. McKenney" To: Andrew Morton Cc: Ingo Molnar , nickpiggin@yahoo.com.au, vegard.nossum@gmail.com, stable@kernel.org, npiggin@suse.de, penberg@cs.helsinki.fi, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: fix lazy vmap purging (use-after-free error) Message-ID: <20090223204429.GU6751@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20090220140157.GA12799@elte.hu> <20090222030030.GD6860@linux.vnet.ibm.com> <20090223051709.GA5990@linux.vnet.ibm.com> <200902240029.37815.nickpiggin@yahoo.com.au> <20090223161726.GD6751@linux.vnet.ibm.com> <20090223111009.d48ff81d.akpm@linux-foundation.org> <20090223193351.GA11921@elte.hu> <20090223120401.b1354133.akpm@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090223120401.b1354133.akpm@linux-foundation.org> User-Agent: Mutt/1.5.15+20070412 (2007-04-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 23, 2009 at 12:04:01PM -0800, Andrew Morton wrote: > On Mon, 23 Feb 2009 20:33:51 +0100 > Ingo Molnar wrote: > > > > > > Nice work all (btw. if this patch goes in rather than using system_state, > > > > > then please make the variable __read_mostly). > > > > > > > > Hmmm... I misread this and made system_state be __read_mostly. Let > > > > me know if this is bad, easy to fix if needed. > > > > > > Please don't use system_state. The whole thing is just bad > > > design. It's a global variable, breaks encapsulation, creates > > > interactions etc. CS-101 stuff. > > > > ok, i've removed the patch > > Thanks. > > > - Paul, would you mind to re-send > > your original flag solution, with it marked __read_mostly and > > with the extern declarations put into a suitable header file? > > It would still make sense to mark system_state __read_mostly. > > (That's assuming that __read_mostly makes sense. I still wanna > rename it to __pack_all_write_often_variables_into_the_same_cacheline > and see what happens then) The patch I just posted retains this change. ;-) Thanx, Paul