From: Anshuman Khandual <anshuman.khandual@arm.com>
To: Mike Rapoport <rppt@kernel.org>, linux-arm-kernel@lists.infradead.org
Cc: Andrew Morton <akpm@linux-foundation.org>,
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-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: Re: [PATCH v2 1/4] include/linux/mmzone.h: add documentation for pfn_valid()
Date: Wed, 21 Apr 2021 16:19:15 +0530 [thread overview]
Message-ID: <d31ff896-ea1c-d47c-0d11-34fdcd3b7ad8@arm.com> (raw)
In-Reply-To: <20210421065108.1987-2-rppt@kernel.org>
On 4/21/21 12:21 PM, Mike Rapoport wrote:
> From: Mike Rapoport <rppt@linux.ibm.com>
>
> Add comment describing the semantics of pfn_valid() that clarifies that
> pfn_valid() only checks for availability of a memory map entry (i.e. struct
> page) for a PFN rather than availability of usable memory backing that PFN.
>
> The most "generic" version of pfn_valid() used by the configurations with
> SPARSEMEM enabled resides in include/linux/mmzone.h so this is the most
> suitable place for documentation about semantics of pfn_valid().
>
> Suggested-by: Anshuman Khandual <anshuman.khandual@arm.com>
> Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
> ---
> include/linux/mmzone.h | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 47946cec7584..961f0eeefb62 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -1410,6 +1410,17 @@ static inline int pfn_section_valid(struct mem_section *ms, unsigned long pfn)
> #endif
>
> #ifndef CONFIG_HAVE_ARCH_PFN_VALID
> +/**
> + * pfn_valid - check if there is a valid memory map entry for a PFN
> + * @pfn: the page frame number to check
> + *
> + * Check if there is a valid memory map entry aka struct page for the @pfn.
> + * Note, that availability of the memory map entry does not imply that
> + * there is actual usable memory at that @pfn. The struct page may
> + * represent a hole or an unusable page frame.
> + *
> + * Return: 1 for PFNs that have memory map entries and 0 otherwise
> + */
> static inline int pfn_valid(unsigned long pfn)
> {
> struct mem_section *ms;
>
next prev parent reply other threads:[~2021-04-21 10:48 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 6:51 [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-04-21 6:51 ` [PATCH v2 1/4] include/linux/mmzone.h: add documentation for pfn_valid() Mike Rapoport
2021-04-21 10:49 ` Anshuman Khandual [this message]
2021-04-21 6:51 ` [PATCH v2 2/4] memblock: update initialization of reserved pages Mike Rapoport
2021-04-21 7:49 ` David Hildenbrand
2021-04-21 10:51 ` Anshuman Khandual
2021-04-21 6:51 ` [PATCH v2 3/4] arm64: decouple check whether pfn is in linear map from pfn_valid() Mike Rapoport
2021-04-21 10:59 ` Anshuman Khandual
2021-04-21 12:19 ` Mike Rapoport
2021-04-21 13:13 ` Anshuman Khandual
2021-04-21 6:51 ` [PATCH v2 4/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
2021-04-21 7:49 ` David Hildenbrand
2021-04-21 11:06 ` Anshuman Khandual
2021-04-21 12:24 ` Mike Rapoport
2021-04-21 13:15 ` Anshuman Khandual
2021-04-22 7:00 ` [PATCH v2 0/4] " Kefeng Wang
2021-04-22 7:29 ` Mike Rapoport
2021-04-22 15:28 ` Kefeng Wang
2021-04-23 8:11 ` Kefeng Wang
2021-04-25 7:19 ` arm32: panic in move_freepages (Was [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid()) Mike Rapoport
2021-04-25 7:51 ` Kefeng Wang
2021-04-26 5:20 ` Mike Rapoport
2021-04-26 15:26 ` Kefeng Wang
2021-04-27 6:23 ` Mike Rapoport
2021-04-27 11:08 ` Kefeng Wang
2021-04-28 5:59 ` Mike Rapoport
2021-04-29 0:48 ` Kefeng Wang
2021-04-29 6:57 ` Mike Rapoport
2021-04-29 10:22 ` Kefeng Wang
2021-04-30 9:51 ` Mike Rapoport
2021-04-30 11:24 ` Kefeng Wang
2021-05-03 6:26 ` Mike Rapoport
2021-05-03 8:07 ` David Hildenbrand
2021-05-03 8:44 ` Mike Rapoport
2021-05-06 12:47 ` Kefeng Wang
2021-05-07 7:17 ` Kefeng Wang
2021-05-07 10:30 ` Mike Rapoport
2021-05-07 12:34 ` Kefeng Wang
2021-05-09 5:59 ` Mike Rapoport
2021-05-10 3:10 ` Kefeng Wang
2021-05-11 8:48 ` Mike Rapoport
2021-05-12 3:08 ` Kefeng Wang
2021-05-12 8:26 ` Mike Rapoport
2021-05-13 3:44 ` Kefeng Wang
2021-05-13 10:55 ` Mike Rapoport
2021-05-14 2:18 ` Kefeng Wang
2021-05-12 3:50 ` Matthew Wilcox
2021-04-25 6:59 ` [PATCH v2 0/4] arm64: drop pfn_valid_within() and simplify pfn_valid() Mike Rapoport
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