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Date: Mon, 28 Aug 2017 15:35:11 -0700
From: Andi Kleen <ak@linux.intel.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
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        Ingo Molnar <mingo@redhat.com>, hpa@zytor.com,
        Will Deacon <will.deacon@arm.com>, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, haren@linux.vnet.ibm.com,
        khandual@linux.vnet.ibm.com, npiggin@gmail.com, bsingharora@gmail.com,
        Tim Chen <tim.c.chen@linux.intel.com>, linuxppc-dev@lists.ozlabs.org,
        x86@kernel.org
Subject: Re: [PATCH v2 14/20] mm: Provide speculative fault infrastructure
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> That makes me extremely nervous... there could be all sort of
> assumptions esp. in arch code about the fact that we never populate the
> tree without the mm sem.
> 
> We'd have to audit archs closely. Things like the page walk cache
> flushing on power etc...

Yes the whole thing is quite risky. Probably will need some
kind of per architecture opt-in scheme?

-Andi