From: Trond Myklebust Subject: Re: ->migratepage aops for nfs missing Date: Tue, 04 Aug 2009 16:53:06 -0400 Message-ID: <1249419186.5377.20.camel@heimdal.trondhjem.org> References: <20090804202648.GA12484@basil.fritz.box> Mime-Version: 1.0 Content-Type: text/plain Cc: linux-nfs@vger.kernel.org To: Andi Kleen , David Howells Return-path: Received: from mx2.netapp.com ([216.240.18.37]:6819 "EHLO mx2.netapp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932281AbZHDUyP (ORCPT ); Tue, 4 Aug 2009 16:54:15 -0400 In-Reply-To: <20090804202648.GA12484-u0/ZJuX+froe6aEkudXLsA@public.gmane.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Tue, 2009-08-04 at 22:26 +0200, Andi Kleen wrote: > Trond, > > Any particular reason ->migratepage is not enabled for > the nfs file aops? > > Is it known to be unsafe to move NFS buffer pages at runtime? > > I have a similar requirement for memory error handling. > > Thanks, > > -Andi Hi Andi, I don't think there are any fundamental problems with migrating NFS page cache pages. In order to handle dirty pages, we'd need to write the equivalent of buffer_migrate_page() in order to transfer the private data, lock and update the 'struct nfs_page' that tracks the page's dirty area. The only thing I'm not 100% sure about is fscache, but I think the correct thing is just to call nfs_fscache_release_page(). David? Cheers Trond -- Trond Myklebust Linux NFS client maintainer NetApp Trond.Myklebust@netapp.com www.netapp.com