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Subject: Re: [PATCH v6 03/11] mm, x86: Add support for eXclusive Page Frame
 Ownership (XPFO)
To: Tycho Andersen <tycho@docker.com>
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Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
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        Marco Benatto <marco.antonio.780@gmail.com>,
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From: Dave Hansen <dave.hansen@intel.com>
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Date: Mon, 13 Nov 2017 14:20:17 -0800
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On 11/09/2017 05:09 PM, Tycho Andersen wrote:
> which I guess is from the additional flags in grow_dev_page() somewhere down
> the stack. Anyway... it seems this is a kernel allocation that's using
> MIGRATE_MOVABLE, so perhaps we need some more fine tuned heuristic than just
> all MOVABLE allocations are un-mapped via xpfo, and all the others are mapped.
> 
> Do you have any ideas?

It still has to do a kmap() or kmap_atomic() to be able to access it.  I
thought you hooked into that.  Why isn't that path getting hit for these?