From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from 173-166-109-252-newengland.hfc.comcastbusiness.net ([173.166.109.252]:35139 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758817Ab1IINAS (ORCPT ); Fri, 9 Sep 2011 09:00:18 -0400 Date: Fri, 9 Sep 2011 09:00:08 -0400 From: Christoph Hellwig To: Mel Gorman Cc: Linux-MM , Linux-Netdev , Linux-NFS , LKML , Andrew Morton , David Miller , Trond Myklebust , Neil Brown , Peter Zijlstra Subject: Re: [PATCH 03/10] mm: Add support for a filesystem to control swap files Message-ID: <20110909130007.GA11810@infradead.org> References: <1315566054-17209-1-git-send-email-mgorman@suse.de> <1315566054-17209-4-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=us-ascii In-Reply-To: <1315566054-17209-4-git-send-email-mgorman@suse.de> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Fri, Sep 09, 2011 at 12:00:47PM +0100, Mel Gorman wrote: > Currently swapfiles are managed entirely by the core VM by using > ->bmap to allocate space and write to the blocks directly. This > patch adds address_space_operations methods that allow a filesystem > to optionally control the swapfile. > > int swap_activate(struct file *); > int swap_deactivate(struct file *); > int swap_writepage(struct file *, struct page *, struct writeback_control *); > int swap_readpage(struct file *, struct page *); Just as the last two dozen times this came up: NAK The right fix is to add a filesystem method to support direct-I/O on arbitrary kernel pages, instead of letting the wap abstraction leak into the filesystem.