From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [RFC PATCH V2 5/5] vhost: access vq metadata through kernel
 virtual address
Date: Fri, 8 Mar 2019 14:13:45 -0500
Message-ID: <20190308191345.GB26923@redhat.com>
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Cc: Jerome Glisse <jglisse@redhat.com>,
        "Michael S. Tsirkin" <mst@redhat.com>, kvm@vger.kernel.org,
        virtualization@lists.linux-foundation.org, netdev@vger.kernel.org,
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To: Jason Wang <jasowang@redhat.com>
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On Fri, Mar 08, 2019 at 04:58:44PM +0800, Jason Wang wrote:
> Can I simply can set_page_dirty() before vunmap() in the mmu notifier 
> callback, or is there any reason that it must be called within vumap()?

I also don't see any problem in doing it before vunmap. As far as the
mmu notifier and set_page_dirty is concerned vunmap is just
put_page. It's just slower and potentially unnecessary.