From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756832AbbI1Hlk (ORCPT ); Mon, 28 Sep 2015 03:41:40 -0400 Received: from down.free-electrons.com ([37.187.137.238]:53647 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756193AbbI1Hli convert rfc822-to-8bit (ORCPT ); Mon, 28 Sep 2015 03:41:38 -0400 Date: Mon, 28 Sep 2015 09:41:34 +0200 From: Boris Brezillon To: "Bean Huo =?UTF-8?B?6ZyN5paM5paM?= (beanhuo)" Cc: "dedekind1@gmail.com" , "adrian.hunter@intel.com" , "computersforpeace@gmail.com" , "baruch@tkos.co.il" , "asierra@xes-inc.com" , "guz.fnst@cn.fujitsu.com" , "gsi@denx.de" , "richard@nod.at" , David Woodhouse , "linux-mtd@lists.infradead.org" , "Frank Liu =?UTF-8?B?5YiY576k?= (frankliu)" , Andrea Scian , "Peter Pan =?UTF-8?B?5r2Y5p+P5a6P?= (peterpan)" , "Karl Zhang =?UTF-8?B?5byg5Y+M6ZSj?= (karlzhang)" , Iwo Mergler , "Jeff Lauruhn (jlauruhn)" , Stefan Roese , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 0/9] drivers:mtd:UBI: add bakvol module for MLC NAND paired page issue Message-ID: <20150928094134.2ab8557e@bbrezillon> In-Reply-To: References: X-Mailer: Claws Mail 3.11.1 (GTK+ 2.24.27; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Bean, Next time you send a patch series, could send all the patches in reply to the cover letter? On Mon, 28 Sep 2015 07:02:35 +0000 Bean Huo 霍斌斌 (beanhuo) wrote: > Hello, > > This series aims at adding a bakvol module for MLC NAND paired page > Power loss protection. > MLC NAND paired page power loss is a known issue so far, MLC NAND pages are > coupled in a sense that if you cut power while writing to a page, you corrupt not only > this page, but also one of the previous pages which is paired with the current one. > Currently, there is no a perfect solution for this. > This paired page solution is based on NAND multiple plane program feature. For this > Patch, only used dual plane page program, means two different plane pages can > Be programmed together at the same time. > Dual plane page program only implements in backup operation. Only lower page data > Be duplicated and back up into a internal log volume by dual plane program method. Hm, I'm not very fond of the idea, especially because of the complexity caused by dual plane program operations (you can't take a random block to write your backup on it, which means WL is complexified too), and the fact that you're duplicating data (thus introducing a performance penalty and storage overhead). > > This patch has been testing on Micron 70s/80s/90s MLC NAND. > Of course there are some places needed to be improved and simplified. > > Any suggestion and comments welcomed. Sure, I'll try to review it soon. Thanks for submitting those patches. Best Regards, Boris -- Boris Brezillon, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com