From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vk0-f72.google.com (mail-vk0-f72.google.com [209.85.213.72]) by kanga.kvack.org (Postfix) with ESMTP id B9FAC6B0005 for ; Fri, 15 Apr 2016 14:24:14 -0400 (EDT) Received: by mail-vk0-f72.google.com with SMTP id e185so216449532vkb.2 for ; Fri, 15 Apr 2016 11:24:14 -0700 (PDT) Received: from mx1.redhat.com (mx1.redhat.com. [209.132.183.28]) by mx.google.com with ESMTPS id w186si24186463qhe.26.2016.04.15.11.24.13 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Apr 2016 11:24:14 -0700 (PDT) From: Jeff Moyer Subject: Re: [PATCH v2 5/5] dax: handle media errors in dax_do_io References: <1459303190-20072-1-git-send-email-vishal.l.verma@intel.com> <1459303190-20072-6-git-send-email-vishal.l.verma@intel.com> <1460739288.3012.3.camel@intel.com> <1460741821.3012.11.camel@intel.com> Date: Fri, 15 Apr 2016 14:24:10 -0400 In-Reply-To: (Dan Williams's message of "Fri, 15 Apr 2016 11:17:39 -0700") Message-ID: MIME-Version: 1.0 Content-Type: text/plain Sender: owner-linux-mm@kvack.org List-ID: To: Dan Williams Cc: "Verma, Vishal L" , "hch@infradead.org" , "jack@suse.cz" , "axboe@fb.com" , "linux-nvdimm@ml01.01.org" , "david@fromorbit.com" , "linux-kernel@vger.kernel.org" , "xfs@oss.sgi.com" , "linux-block@vger.kernel.org" , "linux-mm@kvack.org" , "viro@zeniv.linux.org.uk" , "linux-fsdevel@vger.kernel.org" , "akpm@linux-foundation.org" , "linux-ext4@vger.kernel.org" , "Wilcox, Matthew R" Dan Williams writes: > On Fri, Apr 15, 2016 at 11:06 AM, Jeff Moyer wrote: >> Dan Williams writes: >> >>>>> There's a lot of special casing here, so you might consider adding >>>>> comments. >>>> >>>> Correct - maybe we should reconsider wrapper-izing this? :) >>> >>> Another option is just to skip dax_do_io() and this special casing >>> fallback entirely if errors are present. I.e. only attempt dax_do_io >>> when: IS_DAX() && gendisk->bb && bb->count == 0. >> >> So, if there's an error anywhere on the device, penalize all I/O (not >> just writes, and not just on sectors that are bad)? I'm not sure that's >> a great plan, either. >> > > If errors are rare how much are we actually losing in practice? How long is a piece of string? > Moreover, we're going to do the full badblocks lookup anyway when we > call ->direct_access(). If we had that information earlier we can > avoid this fallback dance. None of the proposed approaches looks clean to me. I'll go along with whatever you guys think is best. I am in favor of wrapping up all that duplicated code, though. Cheers, Jeff -- 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