From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id A61F66B02A6 for ; Wed, 28 Jul 2010 18:58:09 -0400 (EDT) Received: by pzk33 with SMTP id 33so2532525pzk.14 for ; Wed, 28 Jul 2010 15:58:05 -0700 (PDT) Date: Thu, 29 Jul 2010 07:57:56 +0900 From: Minchan Kim Subject: Re: [PATCH] Tight check of pfn_valid on sparsemem - v4 Message-ID: <20100728225756.GA6108@barrios-desktop> References: <20100727171351.98d5fb60.kamezawa.hiroyu@jp.fujitsu.com> <20100728155617.GA5401@barrios-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Christoph Lameter Cc: KAMEZAWA Hiroyuki , Milton Miller , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Russell King , Mel Gorman , Johannes Weiner , Kukjin Kim List-ID: On Wed, Jul 28, 2010 at 12:02:16PM -0500, Christoph Lameter wrote: > On Thu, 29 Jul 2010, Minchan Kim wrote: > > invalid memmap pages will be freed by free_memmap and will be used > > on any place. How do we make sure it has PG_reserved? > > Not present memmap pages make pfn_valid fail already since there is no > entry for the page table (vmemmap) or blocks are missing in the sparsemem > tables. > > > Maybe I don't understand your point. > > I thought we are worrying about holes in the memmap blocks containing page > structs. Some page structs point to valid pages and some are not. The > invalid page structs need to be marked consistently to allow the check. The thing is that memmap pages which contains struct page array on hole will be freed by free_memmap in ARM. Please loot at arch/arm/mm/init.c. And it will be used by page allocator as free pages. -- 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