From mboxrd@z Thu Jan  1 00:00:00 1970
From: Dan Williams <dan.j.williams-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
Subject: Re: [PATCH v2 0/2] kvm "fake DAX" device
Date: Sat, 13 Oct 2018 09:06:07 -0700
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Cc: Kevin Wolf <kwolf-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Jan Kara <jack-AlSwsSmVLrQ@public.gmane.org>, Xiao Guangrong <xiaoguangrong.eric-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, KVM list <kvm-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Rik van Riel <riel-ebMLmSuQjDVBDgjK7y7TUQ@public.gmane.org>, linux-nvdimm <linux-nvdimm-y27Ovi1pjclAfugRpC6u6w@public.gmane.org>, David Hildenbrand <david-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Linux Kernel Mailing List <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>, Qemu Developers <qemu-devel-qX2TKyscuCcdnm+yROfE0A@public.gmane.org>, Christoph Hellwig <hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>, Igor Mammedov <imammedo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, "Michael S. Tsirkin" <mst-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Stefan Hajnoczi <stefanha-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, zwisler-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, lcapitulino-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, Paolo Bonzini <pbonzini-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Nitesh Narayan Lal <nilal-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Eric Blake <eblake-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
List-Id: linux-nvdimm@lists.01.org

On Fri, Oct 12, 2018 at 10:00 PM Pankaj Gupta <pagupta-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> 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