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Message-ID: <e1f78a33-18bb-bd6e-eede-e5e86758a4d0@deltatee.com>
Date: Tue, 13 Aug 2019 10:49:51 -0600
From: Logan Gunthorpe <logang@...tatee.com>
To: Paul Walmsley <paul.walmsley@...ive.com>
Cc: Greentime Hu <green.hu@...il.com>, Rob Herring <robh@...nel.org>,
Albert Ou <aou@...s.berkeley.edu>,
Andrew Waterman <andrew@...ive.com>,
Palmer Dabbelt <palmer@...ive.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Stephen Bates <sbates@...thlin.com>,
Olof Johansson <olof@...om.net>, greentime.hu@...ive.com,
linux-riscv@...ts.infradead.org,
Michael Clark <michaeljclark@....com>,
Christoph Hellwig <hch@....de>, linux-mm@...r.kernel.org
Subject: Re: [PATCH v4 2/2] RISC-V: Implement sparsemem
On 2019-08-13 10:39 a.m., Paul Walmsley wrote:
> On Tue, 13 Aug 2019, Logan Gunthorpe wrote:
>
>> On 2019-08-13 12:04 a.m., Greentime Hu wrote:
>>
>>> Every architecture with mmu defines their own pfn_valid().
>>
>> Not true. Arm64, for example just uses the generic implementation in
>> mmzone.h.
>
> arm64 seems to define their own:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/Kconfig#n899
Oh, yup. My mistake.
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm64/mm/init.c#n235
>
> While there are many architectures which have their own pfn_valid();
> oddly, almost none of them set HAVE_ARCH_PFN_VALID ?
Yes, much of this is super confusing. Seems HAVE_ARCH_PFN_VALID only
matters if SPARSEMEM is set. So risc-v probably doesn't need to set it
and we just need a #ifdef !CONFIG_FLATMEM around the pfn_valid
definition like other arches.
Logan
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