Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936306AbXFFVe5 (ORCPT ); Wed, 6 Jun 2007 17:34:57 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935187AbXFFVeF (ORCPT ); Wed, 6 Jun 2007 17:34:05 -0400 Received: from gprs189-60.eurotel.cz ([160.218.189.60]:1390 "EHLO spitz.ucw.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S936167AbXFFVeD (ORCPT ); Wed, 6 Jun 2007 17:34:03 -0400 Date: Wed, 6 Jun 2007 21:26:06 +0000 From: Pavel Machek To: Rene Herman Cc: Jeremy Fitzhardinge , "John Anthony Kazos Jr." , Christoph Lameter , Andrew Morton , Pekka Enberg , Linus Torvalds , linux-kernel@vger.kernel.org Subject: Re: SLUB: Return ZERO_SIZE_PTR for kmalloc(0) Message-ID: <20070606212605.GA6711@ucw.cz> References: <46646747.2080803@cs.helsinki.fi> <20070604155355.bf29a3a8.akpm@linux-foundation.org> <466523E0.3050605@gmail.com> <46655CEC.7070900@gmail.com> <466575EE.70901@goop.org> <46657988.6060901@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <46657988.6060901@gmail.com> User-Agent: Mutt/1.5.9i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1450 Lines: 42 Hi! > >>No, what we have is a sizeof(pointer) sized pointer > >>pointing to an > >>object of size zero. ZERO_SIZE_PTR is butt-ugly. With > >>a really ugly butt. > > > >It doesn't matter. It will never, ever, be used by > >anything except the > >kmalloc internals. No client code should ever use the > >constant for > >anything. > > Yes, I'm aware of this (I should snip less) but I still > feel it's not a good name. When I read say "a 64-bit > pointer" I immediately take that to mean a pointer of > size 64-bit, not a pointer to 64-bits and only it not > making any sense would stop me from interpreting > "ZERO_SIZE_PTR" similarly. > > Yes, it's internal but given that this is open-source > which, optimistically, is read many more times than it's > written one should still strive for code that reads nice > as far as I'm concerned. It's obviously also not hugely > important but it's just that ZERO_SIZE_PTR makes my neck > hair stand up. PTR_TO_NOTHING? PTR_TO_0BYTES? PTR_TO_0SIZE? PTR_TO_ZERO_SIZE? NOT_QUITE_NULL? :-) FULL? Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html - 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/