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In-Reply-To: <20190131103022.10218-1-peterx@redhat.com>
To:     Peter Xu <peterx@redhat.com>, linux-kernel@vger.kernel.org
From:   Michael Ellerman <patch-notifications@ellerman.id.au>
Cc:     Andrea Arcangeli <aarcange@redhat.com>,
        Alexey Kardashevskiy <aik@ozlabs.ru>,
        Mark Hairgrove <mhairgrove@nvidia.com>, peterx@redhat.com,
        Jerome Glisse <jglisse@redhat.com>,
        Paul Mackerras <paulus@samba.org>,
        Alistair Popple <alistair@popple.id.au>,
        linuxppc-dev@lists.ozlabs.org, Jason Wang <jasowang@redhat.com>,
        David Gibson <david@gibson.dropbear.id.au>
Subject: Re: powerpc/powernv/npu: Remove redundant change_pte() hook
Message-Id: <445RN24dKKz9sB3@ozlabs.org>
Date:   Fri, 22 Feb 2019 20:47:46 +1100 (AEDT)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Thu, 2019-01-31 at 10:30:22 UTC, Peter Xu wrote:
> The change_pte() notifier was designed to use as a quick path to
> update secondary MMU PTEs on write permission changes or PFN changes.
> For KVM, it could reduce the vm-exits when vcpu faults on the pages
> that was touched up by KSM.  It's not used to do cache invalidations,
> for example, if we see the notifier will be called before the real PTE
> update after all (please see set_pte_at_notify that set_pte_at was
> called later).
> 
> All the necessary cache invalidation should all be done in
> invalidate_range() already.
> 
> CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> CC: Paul Mackerras <paulus@samba.org>
> CC: Michael Ellerman <mpe@ellerman.id.au>
> CC: Alistair Popple <alistair@popple.id.au>
> CC: Alexey Kardashevskiy <aik@ozlabs.ru>
> CC: Mark Hairgrove <mhairgrove@nvidia.com>
> CC: Balbir Singh <bsingharora@gmail.com>
> CC: David Gibson <david@gibson.dropbear.id.au>
> CC: Andrea Arcangeli <aarcange@redhat.com>
> CC: Jerome Glisse <jglisse@redhat.com>
> CC: Jason Wang <jasowang@redhat.com>
> CC: linuxppc-dev@lists.ozlabs.org
> CC: linux-kernel@vger.kernel.org
> Signed-off-by: Peter Xu <peterx@redhat.com>
> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
> Reviewed-by: Alistair Popple <alistair@popple.id.au>
> Reviewed-by: Balbir Singh <bsingharora@gmail.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/1b58a975be36994a572ae3b3fb3e0232

cheers