From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762752AbZBYPi1 (ORCPT ); Wed, 25 Feb 2009 10:38:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754474AbZBYPiQ (ORCPT ); Wed, 25 Feb 2009 10:38:16 -0500 Received: from palinux.external.hp.com ([192.25.206.14]:34147 "EHLO mail.parisc-linux.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753630AbZBYPiP (ORCPT ); Wed, 25 Feb 2009 10:38:15 -0500 Date: Wed, 25 Feb 2009 08:37:57 -0700 From: Matthew Wilcox To: Peter Zijlstra Cc: Justin Chen , linux-arch@vger.kernel.org, bjorn.helgaas@hp.com, justin.chen@hp.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 00/15] bitops: Change bitmap index from int to unsigned long Message-ID: <20090225153757.GP16891@parisc-linux.org> References: <200902250441.UAA12527@hpdst41.cup.hp.com> <1235544888.4645.2942.camel@laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1235544888.4645.2942.camel@laptop> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 25, 2009 at 07:54:48AM +0100, Peter Zijlstra wrote: > unsigned int wasn't large enough? Adding one more bit only doubles the maximum size. That buys us, what, another eighteen months until we have to change it again? Unsigned long seems most sensible to me. Unsigned long long probably isn't worth doing -- you'd have to be using one eighth of your address space on a single bitmap. -- Matthew Wilcox Intel Open Source Technology Centre "Bill, look, we understand that you're interested in selling us this operating system, but compare it to ours. We can't possibly take such a retrograde step."