From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cantor2.suse.de ([195.135.220.15]:38999 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751387Ab1ILJeh (ORCPT ); Mon, 12 Sep 2011 05:34:37 -0400 Date: Mon, 12 Sep 2011 10:34:34 +0100 From: Mel Gorman To: Peter Zijlstra Cc: Christoph Hellwig , Linux-MM , Linux-Netdev , Linux-NFS , LKML , Andrew Morton , David Miller , Trond Myklebust , Neil Brown Subject: Re: [PATCH 03/10] mm: Add support for a filesystem to control swap files Message-ID: <20110912093058.GA3207@suse.de> References: <1315566054-17209-1-git-send-email-mgorman@suse.de> <1315566054-17209-4-git-send-email-mgorman@suse.de> <20110909130007.GA11810@infradead.org> <20110909131550.GV14369@suse.de> <20110909133611.GB8155@infradead.org> <1315818285.26517.18.camel@twins> Content-Type: text/plain; charset=iso-8859-15 In-Reply-To: <1315818285.26517.18.camel@twins> Sender: linux-nfs-owner@vger.kernel.org List-ID: MIME-Version: 1.0 On Mon, Sep 12, 2011 at 11:04:45AM +0200, Peter Zijlstra wrote: > On Fri, 2011-09-09 at 09:36 -0400, Christoph Hellwig wrote: > > The equivalent of ->direct_IO should be used for both reads and writes. > > So the difference between DIO and swapIO is that swapIO needs the block > map pinned in memory.. So at the very least you'll need those > swap_{activate,deactivate} aops. The read/write-page thingies could > indeed be shared with DIO. > I'm travelling at the moment so it'll be later in the week when I investigate properly but I agree swap_[de|a]ctivate are still necessary. NFS does not need to pin a block map but it's still necessary for calling xs_set_memalloc. -- Mel Gorman SUSE Labs