From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: linux-nfs-owner@vger.kernel.org Received: from mx1.redhat.com ([209.132.183.28]:17402 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756762Ab2FTPum (ORCPT ); Wed, 20 Jun 2012 11:50:42 -0400 Message-ID: <4FE1F109.1060200@redhat.com> Date: Wed, 20 Jun 2012 11:49:29 -0400 From: Rik van Riel MIME-Version: 1.0 To: Mel Gorman CC: Andrew Morton , Linux-MM , Linux-Netdev , Linux-NFS , LKML , David Miller , Trond Myklebust , Neil Brown , Christoph Hellwig , Peter Zijlstra , Mike Christie , Eric B Munson Subject: Re: [PATCH 03/12] mm: Methods for teaching filesystems about PG_swapcache pages References: <1340185081-22525-1-git-send-email-mgorman@suse.de> <1340185081-22525-4-git-send-email-mgorman@suse.de> In-Reply-To: <1340185081-22525-4-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Sender: linux-nfs-owner@vger.kernel.org List-ID: On 06/20/2012 05:37 AM, Mel Gorman wrote: > In order to teach filesystems to handle swap cache pages, three new > page functions are introduced: > > pgoff_t page_file_index(struct page *); > loff_t page_file_offset(struct page *); > struct address_space *page_file_mapping(struct page *); > > page_file_index() - gives the offset of this page in the file in > PAGE_CACHE_SIZE blocks. Like page->index is for mapped pages, this > function also gives the correct index for PG_swapcache pages. > > page_file_offset() - uses page_file_index(), so that it will give > the expected result, even for PG_swapcache pages. > > page_file_mapping() - gives the mapping backing the actual page; > that is for swap cache pages it will give swap_file->f_mapping. > > Signed-off-by: Peter Zijlstra > Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel