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Date:   Tue, 15 Sep 2020 17:29:56 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     Ralph Campbell <rcampbell@nvidia.com>
Cc:     Dan Williams <dan.j.williams@intel.com>,
        Linux MM <linux-mm@kvack.org>, kvm-ppc@vger.kernel.org,
        nouveau@lists.freedesktop.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Ira Weiny <ira.weiny@intel.com>,
        Matthew Wilcox <willy@infradead.org>,
        Jerome Glisse <jglisse@redhat.com>,
        John Hubbard <jhubbard@nvidia.com>,
        Alistair Popple <apopple@nvidia.com>,
        Christoph Hellwig <hch@lst.de>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Bharata B Rao <bharata@linux.ibm.com>,
        Zi Yan <ziy@nvidia.com>,
        "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Paul Mackerras <paulus@ozlabs.org>,
        Ben Skeggs <bskeggs@redhat.com>,
        Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: remove extra ZONE_DEVICE struct page refcount
Message-ID: <20200915162956.GA21990@infradead.org>
References: <20200914224509.17699-1-rcampbell@nvidia.com>
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On Mon, Sep 14, 2020 at 04:53:25PM -0700, Ralph Campbell wrote:
> Since set_page_refcounted() is defined in mm_interal.h I would have to
> move the definition to someplace like page_ref.h or have the drivers
> cal init_page_count() or set_page_count() since get_page() calls
> VM_BUG_ON_PAGE() if refcount == 0.
> I'll move set_page_refcounted() since that is what the page allocator
> uses and seems named for the purpose.

I don't think any of the three ->page_free instances even cares about
the page refcount.