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Date:   Tue, 5 Nov 2019 19:51:14 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Thomas =?ISO-8859-1?Q?Hellstr=F6m?= (VMware) 
        <thomas_os@shipmail.org>
Cc:     linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        torvalds@linux-foundation.org,
        Thomas Hellstrom <thellstrom@vmware.com>,
        Matthew Wilcox <willy@infradead.org>,
        Will Deacon <will.deacon@arm.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Rik van Riel <riel@surriel.com>,
        Minchan Kim <minchan@kernel.org>,
        Michal Hocko <mhocko@suse.com>,
        Huang Ying <ying.huang@intel.com>,
        =?ISO-8859-1?Q?J=E9r=F4me?= Glisse <jglisse@redhat.com>,
        "Kirill A . Shutemov" <kirill@shutemov.name>
Subject: Re: [PATCH v6 4/8] mm: Add write-protect and clean utilities for
 address space ranges
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        <20191014132204.7721-5-thomas_os@shipmail.org>
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On Mon, 14 Oct 2019 15:22:00 +0200 Thomas Hellstr=F6m (VMware) <thomas_os@s=
hipmail.org> wrote:

> Add two utilities to 1) write-protect and 2) clean all ptes pointing into
> a range of an address space.
> The utilities are intended to aid in tracking dirty pages (either
> driver-allocated system memory or pci device memory).
> The write-protect utility should be used in conjunction with
> page_mkwrite() and pfn_mkwrite() to trigger write page-faults on page
> accesses. Typically one would want to use this on sparse accesses into
> large memory regions. The clean utility should be used to utilize
> hardware dirtying functionality and avoid the overhead of page-faults,
> typically on large accesses into small memory regions.

Not fully comfortable reviewing this one.

> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -736,4 +736,7 @@ config ARCH_HAS_PTE_SPECIAL
>  config ARCH_HAS_HUGEPD
>  	bool
> =20
> +config MAPPING_DIRTY_HELPERS
> +        bool
> +

But given this, it's your problem ;)  So

Acked-by: Andrew Morton <akpm@linux-foundation.org>

Yes, please proceed with merging [1-4] via a drm tree.