From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ig0-f200.google.com (mail-ig0-f200.google.com [209.85.213.200]) by kanga.kvack.org (Postfix) with ESMTP id 31B7E6B0005 for ; Fri, 15 Apr 2016 14:17:41 -0400 (EDT) Received: by mail-ig0-f200.google.com with SMTP id z8so37835346igl.3 for ; Fri, 15 Apr 2016 11:17:41 -0700 (PDT) Received: from mail-ob0-x22d.google.com (mail-ob0-x22d.google.com. [2607:f8b0:4003:c01::22d]) by mx.google.com with ESMTPS id a65si9380852otc.128.2016.04.15.11.17.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 15 Apr 2016 11:17:40 -0700 (PDT) Received: by mail-ob0-x22d.google.com with SMTP id n10so9687293obb.2 for ; Fri, 15 Apr 2016 11:17:40 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: 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 11:17:39 -0700 Message-ID: Subject: Re: [PATCH v2 5/5] dax: handle media errors in dax_do_io From: Dan Williams Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Jeff Moyer 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" 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? 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. -- 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