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Date:   Wed, 9 Feb 2022 07:23:45 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Dan Williams <dan.j.williams@intel.com>
Cc:     Christoph Hellwig <hch@lst.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
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        "Pan, Xinhui" <Xinhui.Pan@amd.com>,
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        Karol Herbst <kherbst@redhat.com>,
        Lyude Paul <lyude@redhat.com>, Jason Gunthorpe <jgg@ziepe.ca>,
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Subject: Re: [PATCH 7/8] mm: remove the extra ZONE_DEVICE struct page
 refcount
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On Tue, Feb 08, 2022 at 07:30:11PM -0800, Dan Williams wrote:
> Interesting. I had expected that to really fix the refcount problem
> that fs/dax.c would need to start taking real page references as pages
> were added to a mapping, just like page cache.

I think we should do that eventually.  But I think this series that
just attacks the device private type and extends to the device coherent
and p2p enhacements is a good first step to stop the proliferation of
the one off refcount and to allow to deal with the fsdax pages in another
more focuessed series.