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From:   Mike Rapoport <rppt@kernel.org>
To:     linux-arm-kernel@lists.infradead.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@kernel.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Will Deacon <will@kernel.org>, kvmarm@lists.cs.columbia.edu,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [RFC/RFT PATCH 0/3] arm64: drop pfn_valid_within() and simplify pfn_valid()
Date:   Wed,  7 Apr 2021 20:26:04 +0300
Message-Id: <20210407172607.8812-1-rppt@kernel.org>
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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 only boot tested on qemu-system-aarch64 so I'd really
appreciate memory stress tests on real hardware.

If this actually works we'll be one step closer to drop custom pfn_valid()
on arm64 altogether.

Mike Rapoport (3):
  memblock: update initialization of reserved pages
  arm64: decouple check whether pfn is normal memory from pfn_valid()
  arm64: drop pfn_valid_within() and simplify pfn_valid()

 arch/arm64/Kconfig              |  3 ---
 arch/arm64/include/asm/memory.h |  2 +-
 arch/arm64/include/asm/page.h   |  1 +
 arch/arm64/kvm/mmu.c            |  2 +-
 arch/arm64/mm/init.c            | 10 ++++++++--
 arch/arm64/mm/ioremap.c         |  4 ++--
 arch/arm64/mm/mmu.c             |  2 +-
 mm/memblock.c                   | 23 +++++++++++++++++++++--
 8 files changed, 35 insertions(+), 12 deletions(-)


base-commit: e49d033bddf5b565044e2abe4241353959bc9120
-- 
2.28.0