From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 8A82521E0B9F2 for ; Mon, 12 Feb 2018 14:47:52 -0800 (PST) From: Jeff Moyer Subject: Re: [PATCH v2] libnvdimm: re-enable deep flush for pmem devices References: <151847194459.58291.11339638808076622981.stgit@djiang5-desk3.ch.intel.com> Date: Mon, 12 Feb 2018 17:53:40 -0500 In-Reply-To: <151847194459.58291.11339638808076622981.stgit@djiang5-desk3.ch.intel.com> (Dave Jiang's message of "Mon, 12 Feb 2018 14:46:13 -0700") Message-ID: MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Dave Jiang Cc: ross.zwisler@intel.com, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org List-ID: Dave Jiang writes: > Re-enable deep flush so that users always have a way to be sure that a write > does make it all the way out to the NVDIMM. The PMEM driver writes always > make it "all the way to the NVDIMM", and it relies on the ADR mechanism to > flush the write buffers on power failure. Deep flush is there to explicitly > flush those write buffers to protect against (rare) ADR failure. > This change prevents a regression in deep flush behavior so that applications > can continue to depend on fsync() as a mechanism to trigger deep flush in the > filesystem-dax case. That's still very confusing text. Specifically, the part where you say that pmem driver writes always make it to the DIMM. I think the changelog could start with "Deep flush is there to explicitly flush write buffers...." Anyway, the fix looks right to me. Reviewed-by: Jeff Moyer _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933165AbeBLWxo (ORCPT ); Mon, 12 Feb 2018 17:53:44 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52096 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933084AbeBLWxm (ORCPT ); Mon, 12 Feb 2018 17:53:42 -0500 From: Jeff Moyer To: Dave Jiang Cc: dan.j.williams@intel.com, ross.zwisler@intel.com, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org Subject: Re: [PATCH v2] libnvdimm: re-enable deep flush for pmem devices References: <151847194459.58291.11339638808076622981.stgit@djiang5-desk3.ch.intel.com> X-PGP-KeyID: 1F78E1B4 X-PGP-CertKey: F6FE 280D 8293 F72C 65FD 5A58 1FF8 A7CA 1F78 E1B4 X-PCLoadLetter: What the f**k does that mean? Date: Mon, 12 Feb 2018 17:53:40 -0500 In-Reply-To: <151847194459.58291.11339638808076622981.stgit@djiang5-desk3.ch.intel.com> (Dave Jiang's message of "Mon, 12 Feb 2018 14:46:13 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dave Jiang writes: > Re-enable deep flush so that users always have a way to be sure that a write > does make it all the way out to the NVDIMM. The PMEM driver writes always > make it "all the way to the NVDIMM", and it relies on the ADR mechanism to > flush the write buffers on power failure. Deep flush is there to explicitly > flush those write buffers to protect against (rare) ADR failure. > This change prevents a regression in deep flush behavior so that applications > can continue to depend on fsync() as a mechanism to trigger deep flush in the > filesystem-dax case. That's still very confusing text. Specifically, the part where you say that pmem driver writes always make it to the DIMM. I think the changelog could start with "Deep flush is there to explicitly flush write buffers...." Anyway, the fix looks right to me. Reviewed-by: Jeff Moyer