Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269776AbUJAMnE (ORCPT ); Fri, 1 Oct 2004 08:43:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269777AbUJAMnD (ORCPT ); Fri, 1 Oct 2004 08:43:03 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:13528 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S269776AbUJAMms (ORCPT ); Fri, 1 Oct 2004 08:42:48 -0400 Date: Fri, 1 Oct 2004 13:42:43 +0100 From: Matthew Wilcox To: "Stephen C. Tweedie" Cc: Pavel Machek , linux-kernel , Andrew Morton , Andreas Dilger , "Theodore Ts'o" , "ext2-devel@lists.sourceforge.net" Subject: Re: [Ext2-devel] Re: [Patch 7/10]: ext3 online resize: SMP locking for group metadata Message-ID: <20041001124243.GA16153@parcelfarce.linux.theplanet.co.uk> References: <200409301323.i8UDNo99004796@sisko.scot.redhat.com> <20041001101822.GA18786@elf.ucw.cz> <1096630838.2001.14.camel@sisko.scot.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1096630838.2001.14.camel@sisko.scot.redhat.com> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1179 Lines: 22 On Fri, Oct 01, 2004 at 12:40:38PM +0100, Stephen C. Tweedie wrote: > So I don't want to make it atomic if I can avoid it. It's just an > unsigned long, and I don't know of any cases where a simple read > colliding with a write is going to give the reader a corrupt value. As > long as I get either the old or new value, everything should be fine > with the read/write barriers as they are. I think all Linux architectures guarantee atomic updates of a register-sized naturally-aligned piece of memory. -- "Next the statesmen will invent cheap lies, putting the blame upon the nation that is attacked, and every man will be glad of those conscience-soothing falsities, and will diligently study them, and refuse to examine any refutations of them; and thus he will by and by convince himself that the war is just, and will thank God for the better sleep he enjoys after this process of grotesque self-deception." -- Mark Twain - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/