From: Andrew Morton <akpm@linux-foundation.org>
To: Mike Rapoport <rppt@kernel.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
Subject: Re: [PATCH v4 4/4] arm64: drop pfn_valid_within() and simplify pfn_valid()
Date: Tue, 11 May 2021 16:40:01 -0700 [thread overview]
Message-ID: <20210511164001.7e905659fdbb8a5e190d303a@linux-foundation.org> (raw)
In-Reply-To: <20210511100550.28178-5-rppt@kernel.org>
On Tue, 11 May 2021 13:05:50 +0300 Mike Rapoport <rppt@kernel.org> wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> The arm64's version of pfn_valid() differs from the generic because of two
> reasons:
>
> * Parts of the memory map are freed during boot. This makes it necessary to
> verify that there is actual physical memory that corresponds to a pfn
> which is done by querying memblock.
>
> * There are NOMAP memory regions. These regions are not mapped in the
> linear map and until the previous commit the struct pages representing
> these areas had default values.
>
> As the consequence of absence of the special treatment of NOMAP regions in
> the memory map it was necessary to use memblock_is_map_memory() in
> pfn_valid() and to have pfn_valid_within() aliased to pfn_valid() so that
> generic mm functionality would not treat a NOMAP page as a normal page.
>
> Since the NOMAP regions are now marked as PageReserved(), pfn walkers and
> the rest of core mm will treat them as unusable memory and thus
> pfn_valid_within() is no longer required at all and can be disabled by
> removing CONFIG_HOLES_IN_ZONE on arm64.
>
> pfn_valid() can be slightly simplified by replacing
> memblock_is_map_memory() with memblock_is_memory().
>
> ...
>
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -1052,9 +1052,6 @@ config NEED_PER_CPU_EMBED_FIRST_CHUNK
> def_bool y
> depends on NUMA
>
> -config HOLES_IN_ZONE
> - def_bool y
> -
> source "kernel/Kconfig.hz"
>
> config ARCH_SPARSEMEM_ENABLE
https://lkml.kernel.org/r/20210417075946.181402-1-wangkefeng.wang@huawei.com
already did this, so I simply dropped that hunk? And I don't think the
changelog needs updating for this?
> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
> index 798f74f501d5..fb07218da2c0 100644
> --- a/arch/arm64/mm/init.c
> +++ b/arch/arm64/mm/init.c
> @@ -251,7 +251,7 @@ int pfn_valid(unsigned long pfn)
> if (!early_section(ms))
> return pfn_section_valid(ms, pfn);
>
> - return memblock_is_map_memory(addr);
> + return memblock_is_memory(addr);
> }
> EXPORT_SYMBOL(pfn_valid);
next prev parent reply other threads:[~2021-05-11 23:40 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-11 10:05 [PATCH v4 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-05-11 10:05 ` [PATCH v4 1/4] include/linux/mmzone.h: add documentation for pfn_valid() Mike Rapoport
2021-05-11 10:22 ` Ard Biesheuvel
2021-05-11 10:05 ` [PATCH v4 2/4] memblock: update initialization of reserved pages Mike Rapoport
2021-05-11 10:23 ` Ard Biesheuvel
2021-05-11 10:05 ` [PATCH v4 3/4] arm64: decouple check whether pfn is in linear map from pfn_valid() Mike Rapoport
2021-05-11 10:25 ` Ard Biesheuvel
2021-05-11 10:05 ` [PATCH v4 4/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-05-11 10:26 ` Ard Biesheuvel
2021-05-11 23:40 ` Andrew Morton [this message]
2021-05-12 5:31 ` Mike Rapoport
2021-05-12 3:13 ` [PATCH v4 0/4] " Kefeng Wang
2021-05-12 7:00 ` Ard Biesheuvel
2021-05-12 7:33 ` Mike Rapoport
2021-05-12 7:59 ` Ard Biesheuvel
2021-05-12 8:32 ` Mike Rapoport
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