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Subject: Re: [PATCH v4 0/4] arm64: drop pfn_valid_within() and simplify
 pfn_valid()
To:     Mike Rapoport <rppt@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>
CC:     Anshuman Khandual <anshuman.khandual@arm.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        "David Hildenbrand" <david@redhat.com>,
        Marc Zyngier <maz@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Will Deacon <will@kernel.org>, <kvmarm@lists.cs.columbia.edu>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>
References: <20210511100550.28178-1-rppt@kernel.org>
From:   Kefeng Wang <wangkefeng.wang@huawei.com>
Message-ID: <b4b384c1-0d45-bb7f-3bd4-56cdb15ff2f8@huawei.com>
Date:   Wed, 12 May 2021 11:13:28 +0800
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On 2021/5/11 18:05, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
> 
> Hi,
> 
> These patches aim to remove CONFIG_HOLES_IN_ZONE and essentially hardwire
> pfn_valid_within() to 1.
> 
> The idea is to mark NOMAP pages as reserved in the memory map and restore
> the intended semantics of pfn_valid() to designate availability of struct
> page for a pfn.
> 
> With this the core mm will be able to cope with the fact that it cannot use
> NOMAP pages and the holes created by NOMAP ranges within MAX_ORDER blocks
> will be treated correctly even without the need for pfn_valid_within.
> 
> The patches are boot tested on qemu-system-aarch64.
> 
> I beleive it would be best to route these via mmotm tree.

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>