From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0E6DDC32771 for ; Wed, 15 Jan 2020 20:17:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA19F2064C for ; Wed, 15 Jan 2020 20:17:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=intel-com.20150623.gappssmtp.com header.i=@intel-com.20150623.gappssmtp.com header.b="fpojuKnu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729039AbgAOURx (ORCPT ); Wed, 15 Jan 2020 15:17:53 -0500 Received: from mail-ot1-f65.google.com ([209.85.210.65]:44442 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728596AbgAOURv (ORCPT ); Wed, 15 Jan 2020 15:17:51 -0500 Received: by mail-ot1-f65.google.com with SMTP id h9so17208115otj.11 for ; Wed, 15 Jan 2020 12:17:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=intel-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=dPd0oj72IQTr7Ho1Km4ZWXqORK+AR/nQgrcplLwpJyE=; b=fpojuKnu+Wi5p9+eOGcUnK1tXz/ym+tDyQJR7fiN07JPdlNydPbQ1RuKfL9nYOO/vp ktdoj1LGNeeH0tLetzt6le5Wb0WjNM3TI4p2CjOGGX+EuSOWw0DzUACfhhv8vVjFUZDe W6M8jugyiYMYQ6KmvTTdLB9sA/e2SPnlatCfzz0H0tbTOuYqDFrMchmtCY6PyFUez9hR OJoFqGd7eJNY1E5+nY46wPN/+WfX65rZrOFaITHNzfaWg74cclGgIH9l50y+jzJWSEL7 OLoPXxM4Hj1zKIsYyFEQOBs4ip5mmicI0GLmGXVjvoFJoRTGMOaPmOsh7mhiRTDNLsCU UcPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=dPd0oj72IQTr7Ho1Km4ZWXqORK+AR/nQgrcplLwpJyE=; b=rq9/kX1EdloaxKlBA9hIed12QG8BxpN6JLlIfd8CPIHQJuiV5vJeX8QSTypEcrOuIJ 3XXpuBiX50q1UGHCft7pMYiHteDjlAq7xbrER2fJJ4f+UCTRgC/XVIr0z0Y7Fp4VLe8C TEyBFPcp8+Fyd6BIA6kBDj39Djc+ZiapNu/i7rvsjLtOEw1ZwH7d2BBn32VwF+64STsF ZYNnNXM2XRWBl2smgyKuUQO1kCFBDEz9e8rPPly95wlyNIImyR91B+XoW1Tddqj93hL2 woPLlrrbGvUZvg4wwXju+Lo14z4QFQvJgd45zBf7wskyniXTjCMatKdIJMAS4vR83IHE SDHA== X-Gm-Message-State: APjAAAXCYsHq4TjLPT7wA/D8vaQHPlPvXuo3t7u/4tpK/jgnMMTI/3PO 3WVG+PBZZ5FE+bO+yaeA2fADln8FdvEQPGv+L1KVFA== X-Google-Smtp-Source: APXvYqxa2PtNKtiTJcIUathhM+5vp8w9k5zscIWT4wSuOwLkVVcCWydFq1TB1qX0u3WdgAKuekec5Tb3+clHuOZsZ0c= X-Received: by 2002:a9d:68d3:: with SMTP id i19mr3785693oto.71.1579119471207; Wed, 15 Jan 2020 12:17:51 -0800 (PST) MIME-Version: 1.0 References: <20200107180101.GC15920@redhat.com> <20200107183307.GD15920@redhat.com> <20200109112447.GG27035@quack2.suse.cz> <20200114203138.GA3145@redhat.com> <20200114212805.GB3145@redhat.com> <20200115195617.GA4133@redhat.com> In-Reply-To: <20200115195617.GA4133@redhat.com> From: Dan Williams Date: Wed, 15 Jan 2020 12:17:40 -0800 Message-ID: Subject: Re: [PATCH 01/19] dax: remove block device dependencies To: Vivek Goyal Cc: Jan Kara , "Darrick J. Wong" , Christoph Hellwig , Dave Chinner , Miklos Szeredi , linux-nvdimm , Linux Kernel Mailing List , "Dr. David Alan Gilbert" , virtio-fs@redhat.com, Stefan Hajnoczi , linux-fsdevel , Jeff Moyer Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 15, 2020 at 11:56 AM Vivek Goyal wrote: [..] > > Even the Red Hat > > installation guide example shows mounting on pmem0 directly. [1] > > Below that example it also says. > > "When creating partitions on a pmem device to be used for direct access, > partitions must be aligned on page boundaries. On the Intel 64 and AMD64 > architecture, at least 4KiB alignment for the start and end of the > partition, but 2MiB is the preferred alignment. By default, the parted > tool aligns partitions on 1MiB boundaries. For the first partition, > specify 2MiB as the start of the partition. If the size of the partition > is a multiple of 2MiB, all other partitions are also aligned." > > So documentation is clearly saying dax will work with partitions as well. > And some user might decide to just do that. Yes, of course but my point is that it was ambiguous. I'm going to take a look at how hard it would be to develop a kpartx fallback in udev. If that can live across the driver transition then maybe this can be a non-event for end users that already have that udev update deployed.