From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with SMTP id 1B3F36B004D for ; Wed, 18 Nov 2009 19:26:32 -0500 (EST) Message-ID: <4B049090.1070300@redhat.com> Date: Wed, 18 Nov 2009 19:25:52 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 1/6] mm: define PAGE_MAPPING_FLAGS References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Hugh Dickins Cc: Andrew Morton , Izik Eidus , Andrea Arcangeli , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On 11/10/2009 04:51 PM, Hugh Dickins wrote: > At present we define PageAnon(page) by the low PAGE_MAPPING_ANON bit > set in page->mapping, with the higher bits a pointer to the anon_vma; > and have defined PageKsm(page) as that with NULL anon_vma. > > But KSM swapping will need to store a pointer there: so in preparation > for that, now define PAGE_MAPPING_FLAGS as the low two bits, including > PAGE_MAPPING_KSM (always set along with PAGE_MAPPING_ANON, until some > other use for the bit emerges). > > Declare page_rmapping(page) to return the pointer part of page->mapping, > and page_anon_vma(page) to return the anon_vma pointer when that's what > it is. Use these in a few appropriate places: notably, unuse_vma() has > been testing page->mapping, but is better to be testing page_anon_vma() > (cases may be added in which flag bits are set without any pointer). > > Signed-off-by: Hugh Dickins > > Reviewed-by: Rik van Riel -- 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