From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755283AbXKSSFM (ORCPT ); Mon, 19 Nov 2007 13:05:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754229AbXKSSE7 (ORCPT ); Mon, 19 Nov 2007 13:04:59 -0500 Received: from e36.co.us.ibm.com ([32.97.110.154]:52187 "EHLO e36.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754039AbXKSSE6 (ORCPT ); Mon, 19 Nov 2007 13:04:58 -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: <20071116143019.GA16082@Krystal> References: <20071113193349.214098508@polymtl.ca> <20071113194025.150641834@polymtl.ca> <1195160783.7078.203.camel@localhost> <20071115215142.GA7825@Krystal> <1195164977.27759.10.camel@localhost> <20071116143019.GA16082@Krystal> Content-Type: text/plain Date: Mon, 19 Nov 2007 10:04:45 -0800 Message-Id: <1195495485.27759.115.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 Fri, 2007-11-16 at 09:30 -0500, Mathieu Desnoyers wrote: > I see that the standard macro to get the kernel address from a pfn is : > > asm-x86/page_32.h:#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) > > The question might seem trivial, but I wonder how this deals with large > pages ? Well, first of all, large pages are a virtual addressing concept. We're only talking about physical addresses here. You still address the memory the same way no matter if it is composed of large or small pages. The physical address (and pfn) never change no matter what we do with the page or how we allocate ir. -- Dave From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from d03relay04.boulder.ibm.com (d03relay04.boulder.ibm.com [9.17.195.106]) by e31.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id lAJI50BK017055 for ; Mon, 19 Nov 2007 13:05:00 -0500 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay04.boulder.ibm.com (8.13.8/8.13.8/NCO v8.7) with ESMTP id lAJI4m7f078650 for ; Mon, 19 Nov 2007 11:04:51 -0700 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id lAJI4l7f021908 for ; Mon, 19 Nov 2007 11:04:48 -0700 Subject: Re: [RFC 5/7] LTTng instrumentation mm From: Dave Hansen In-Reply-To: <20071116143019.GA16082@Krystal> References: <20071113193349.214098508@polymtl.ca> <20071113194025.150641834@polymtl.ca> <1195160783.7078.203.camel@localhost> <20071115215142.GA7825@Krystal> <1195164977.27759.10.camel@localhost> <20071116143019.GA16082@Krystal> Content-Type: text/plain Date: Mon, 19 Nov 2007 10:04:45 -0800 Message-Id: <1195495485.27759.115.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Mathieu Desnoyers Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, mbligh@google.com List-ID: On Fri, 2007-11-16 at 09:30 -0500, Mathieu Desnoyers wrote: > I see that the standard macro to get the kernel address from a pfn is : > > asm-x86/page_32.h:#define pfn_to_kaddr(pfn) __va((pfn) << PAGE_SHIFT) > > The question might seem trivial, but I wonder how this deals with large > pages ? Well, first of all, large pages are a virtual addressing concept. We're only talking about physical addresses here. You still address the memory the same way no matter if it is composed of large or small pages. The physical address (and pfn) never change no matter what we do with the page or how we allocate ir. -- Dave -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org