Received: by 2002:ac0:a582:0:0:0:0:0 with SMTP id m2-v6csp2054271imm; Sat, 13 Oct 2018 09:09:46 -0700 (PDT) X-Google-Smtp-Source: ACcGV62sIpwFGikLNAPDmuOYT08whd58mX8kvKWrYIpeWQkij9UDu7PjQKNDahektxPihW572SrR X-Received: by 2002:a63:3152:: with SMTP id x79-v6mr9802534pgx.323.1539446986649; Sat, 13 Oct 2018 09:09:46 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1539446986; cv=none; d=google.com; s=arc-20160816; b=eWMwCIhPbSqrPz2BU4AtJDQLiLHhxiXcADNN/RPhfzkm19UxzvgcvfyhIOy41fa2Yc Ymv03D8TRy0DOxx+GWn0UwHUP/sE9nbXliGojWcuND9fffJSXY+dat1jV/A+DLw1K0hP GccjqM/PFFE64BPrdx6m7pmk3z9QuKSSJKrdhJJ4/QAcOgLo9HFM13OMToQ7aypAxXj5 hE9mJUVweiU+hAooi5aGmLuqZILtC6PIWuVxNZKc32iAgM0Fc3kqg+3GDUl26mZmv56H ng8YB27JpHha8oQ+ItB10s6VypU43FQXHQWj+W8YfWfTRaSRluZi5qoP5hxWq6yYMG+p PwZg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:dkim-signature; bh=cSy8aZNbc+Fp01O7mr7iurX03QUJ9OJYlQTrAqkvWPw=; b=bSR7wdKhS7ULUR3JwPfqHOlM++vL6LCTinIOePlqy7ovmQUsCMOCkXrU1XZclzB2ax 6M79Z5vt0UiZBs6DEL947RCoWW7GbsrFQVRcOaOMFdpkUKdpH3znBjx9PuemB70j2Yge PpexWGt4cKI7kBskF4SSQWMAVNAhapx+tduVjj+UGRVmBC662QjDzozqa7clNhXSHx6K 4qLYgPXqlvwYgRgopNdEdNNTZAqT3ecgq5h8rarUMFtLtdhMhpIAcMyMkBClsbpVpE1t evMs3l0Cd8hKLcbBH2ZeX3yPKWURtYONR4pr1S9CpeIAMAHVjWbr4AUKdoH8kbLGWXhG IGzw== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=hDGEHqrg; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id m29-v6si4872080pgd.361.2018.10.13.09.09.17; Sat, 13 Oct 2018 09:09:46 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@intel-com.20150623.gappssmtp.com header.s=20150623 header.b=hDGEHqrg; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726666AbeJMXoB (ORCPT + 99 others); Sat, 13 Oct 2018 19:44:01 -0400 Received: from mail-ot1-f65.google.com ([209.85.210.65]:35918 "EHLO mail-ot1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726329AbeJMXoA (ORCPT ); Sat, 13 Oct 2018 19:44:00 -0400 Received: by mail-ot1-f65.google.com with SMTP id x4so13742407otg.3 for ; Sat, 13 Oct 2018 09:06:18 -0700 (PDT) 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=cSy8aZNbc+Fp01O7mr7iurX03QUJ9OJYlQTrAqkvWPw=; b=hDGEHqrgK4JSJfehJqv2wXlWnet/OGIHzcUE3UOm0uULgIRbkjOJmYaKaXeiRvwa0s 86kuBoD+TNbeKTHvMIsa7UuuAWHucbuhj7azuQIBTwAX4kSCQeKQiPN53a6X/dt4lmfo 1uxMrGVYgojBA3jzUxilsidTGChVg4XJm8pnqOP7Z8aAKMF2nAcnjqVN0dzEItcL/Vr+ PcLpNw3rkruXvBC65QhQbQ8MupdIy8e8nO4XtDTH69LLLbVxrXx4cQU8ZYoxl+YK8U3P NgONb0vL+sS+zCrWaDQ9cYtgfiztgX/hmylGsFIVD0rG7lGvDeu9Fg/i4DjSMFtIyjE9 LV6g== 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=cSy8aZNbc+Fp01O7mr7iurX03QUJ9OJYlQTrAqkvWPw=; b=VNOCYZ5ZoH+vcud9Y8ZMZPlBd1njk7Jk97dot6bkk1WwksHjcRxU8NobRfrwaL0nR8 5VGOWCwS7z1vplqXKs/O9IyM3X62/kAjWYY4kkLXBE0q3ITJ3qJs4tmtPM2OWK3eUXCl mib4omCWLqije3OZ3+ei7k0V4NedVNQtDIYBS1EKppRNeoftwQE76vzaP+mBr/AIfzsl RzmOljXrg71Z8rnbeAd03rERmbl2OevD6tMrkxRHngtLF+ZSl+/2KkwfY1Y8rt5oLikU R3rsbSmrBpf+mu2yFQ41+taRygiowNtsPS4Mz1vHZQURpoleKjBMtKr3fKKlxZoTIsDg aoCg== X-Gm-Message-State: ABuFfoi1Tma27woWjbjzJqee97qXgXOl6r3RyPEIq8OgajBAYzCmpHRf QHOhpQ++XzLn7ORDaRkPDLcHjC6C/6ckQ+ZCRK/JVA== X-Received: by 2002:a9d:758f:: with SMTP id s15mr6414736otk.353.1539446778225; Sat, 13 Oct 2018 09:06:18 -0700 (PDT) MIME-Version: 1.0 References: <20181013050021.11962-1-pagupta@redhat.com> In-Reply-To: <20181013050021.11962-1-pagupta@redhat.com> From: Dan Williams Date: Sat, 13 Oct 2018 09:06:07 -0700 Message-ID: Subject: Re: [PATCH v2 0/2] kvm "fake DAX" device To: Pankaj Gupta Cc: Linux Kernel Mailing List , KVM list , Qemu Developers , linux-nvdimm , Jan Kara , Stefan Hajnoczi , Rik van Riel , Nitesh Narayan Lal , Kevin Wolf , Paolo Bonzini , zwisler@kernel.org, Vishal L Verma , Dave Jiang , David Hildenbrand , Xiao Guangrong , Christoph Hellwig , "Michael S. Tsirkin" , lcapitulino@redhat.com, Igor Mammedov , Eric Blake 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 Fri, Oct 12, 2018 at 10:00 PM Pankaj Gupta wrote: > > This patch series has implementation for "fake DAX". > "fake DAX" is fake persistent memory(nvdimm) in guest > which allows to bypass the guest page cache. This also > implements a VIRTIO based asynchronous flush mechanism. Can we stop calling this 'fake DAX', because it isn't 'DAX' and it's starting to confuse people. This enabling is effectively a host-page-cache-passthrough mechanism not DAX. Let's call the whole approach virtio-pmem, and leave DAX out of the name to hopefully prevent people from wondering why some DAX features are disabled with this driver. For example MAP_SYNC is not compatible with this approach. Additional enabling is need to disable MAP_SYNC in the presence of a virtio-pmem device. See the rough proposal here: https://lkml.org/lkml/2018/4/25/756