From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with SMTP id 7D384600044 for ; Mon, 26 Jul 2010 18:47:31 -0400 (EDT) Received: by iwn2 with SMTP id 2so3733595iwn.14 for ; Mon, 26 Jul 2010 15:47:27 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: References: <1280159163-23386-1-git-send-email-minchan.kim@gmail.com> Date: Tue, 27 Jul 2010 07:47:26 +0900 Message-ID: Subject: Re: [PATCH] Tight check of pfn_valid on sparsemem - v4 From: Minchan Kim Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: Andrew Morton , Russell King , Kukjin Kim , LKML , linux-arm-kernel , linux-mm , KAMEZAWA Hiroyuki , Mel Gorman , Johannes Weiner List-ID: Hi Christoph, On Tue, Jul 27, 2010 at 1:40 AM, Christoph Lameter wrote: > On Tue, 27 Jul 2010, Minchan Kim wrote: > >> This patch registers address of mem_section to memmap itself's page struct's >> pg->private field. This means the page is used for memmap of the section. >> Otherwise, the page is used for other purpose and memmap has a hole. > > What if page->private just happens to be the value of the page struct? > Even if that is not possible today, someday someone may add new > functionality to the kernel where page->pivage == page is used for some > reason. I agree. > > Checking for PG_reserved wont work? Okay. It would be better to consider page point itself with PG_reserved. I will reflect your opinion next version. :) Thanks, Christoph. -- Kind regards, Minchan Kim -- 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