From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: Re: [PATCH 00/15] bitops: Change bitmap index from int to unsigned long Date: Wed, 25 Feb 2009 08:37:57 -0700 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 Return-path: 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 Content-Disposition: inline In-Reply-To: <1235544888.4645.2942.camel@laptop> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra Cc: Justin Chen , linux-arch@vger.kernel.org, bjorn.helgaas@hp.com, justin.chen@hp.com, 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."