From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from ipmail06.adl6.internode.on.net ([150.101.137.145]:43869 "EHLO ipmail06.adl6.internode.on.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752671AbcLMUQN (ORCPT ); Tue, 13 Dec 2016 15:16:13 -0500 Date: Wed, 14 Dec 2016 07:15:15 +1100 From: Dave Chinner To: Jerome Glisse Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [LSF/MM TOPIC] Un-addressable device memory and block/fs implications Message-ID: <20161213201515.GB4326@dastard> References: <20161213181511.GB2305@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20161213181511.GB2305@redhat.com> Sender: linux-block-owner@vger.kernel.org List-Id: linux-block@vger.kernel.org On Tue, Dec 13, 2016 at 01:15:11PM -0500, Jerome Glisse wrote: > I would like to discuss un-addressable device memory in the context of > filesystem and block device. Specificaly how to handle write-back, read, > ... when a filesystem page is migrated to device memory that CPU can not > access. You mean pmem that is DAX-capable that suddenly, without warning, becomes non-DAX capable? If you are not talking about pmem and DAX, then exactly what does "when a filesystem page is migrated to device memory that CPU can not access" mean? What "filesystem page" are we talking about that can get migrated from main RAM to something the CPU can't access? Cheers, Dave. -- Dave Chinner david@fromorbit.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 14 Dec 2016 07:15:15 +1100 From: Dave Chinner To: Jerome Glisse Cc: lsf-pc@lists.linux-foundation.org, linux-mm@kvack.org, linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: Re: [LSF/MM TOPIC] Un-addressable device memory and block/fs implications Message-ID: <20161213201515.GB4326@dastard> References: <20161213181511.GB2305@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161213181511.GB2305@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: On Tue, Dec 13, 2016 at 01:15:11PM -0500, Jerome Glisse wrote: > I would like to discuss un-addressable device memory in the context of > filesystem and block device. Specificaly how to handle write-back, read, > ... when a filesystem page is migrated to device memory that CPU can not > access. You mean pmem that is DAX-capable that suddenly, without warning, becomes non-DAX capable? If you are not talking about pmem and DAX, then exactly what does "when a filesystem page is migrated to device memory that CPU can not access" mean? What "filesystem page" are we talking about that can get migrated from main RAM to something the CPU can't access? Cheers, Dave. -- Dave Chinner david@fromorbit.com -- 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