From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752015AbXKSTnS (ORCPT ); Mon, 19 Nov 2007 14:43:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751170AbXKSTnI (ORCPT ); Mon, 19 Nov 2007 14:43:08 -0500 Received: from e6.ny.us.ibm.com ([32.97.182.146]:59604 "EHLO e6.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750925AbXKSTnG (ORCPT ); Mon, 19 Nov 2007 14:43:06 -0500 Subject: Re: [RFC 5/7] LTTng instrumentation mm From: Dave Hansen To: Mathieu Desnoyers Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mbligh@google.com In-Reply-To: <20071119185258.GA998@Krystal> References: <20071113193349.214098508@polymtl.ca> <20071113194025.150641834@polymtl.ca> <1195160783.7078.203.camel@localhost> <20071115215142.GA7825@Krystal> <1195164977.27759.10.camel@localhost> <20071116144742.GA17255@Krystal> <1195495626.27759.119.camel@localhost> <20071119185258.GA998@Krystal> Content-Type: text/plain Date: Mon, 19 Nov 2007 11:43:01 -0800 Message-Id: <1195501381.27759.127.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2007-11-19 at 13:52 -0500, Mathieu Desnoyers wrote: > > > So I guess the result is a pointer ? Should this be expected ? > > > > Nope. 'pointer - pointer' is an integer. Just solve this equation for > > integer: > > > > 'pointer + integer = pointer' > > > > Well, using page_to_pfn turns out to be ugly in markers (and in > printks) then. Depending on the architecture, it will result in either > an unsigned long (x86_64) or an unsigned int (i386), which corresponds > to %lu or %u and will print a warning if we don't cast it explicitly. Casting the i386 one to be an unconditional 'unsigned long' shouldn't be an issue. We don't generally expect pfns to fit into ints anyway. -- Dave