From: Christophe Leroy <christophe.leroy@c-s.fr>
To: Qian Cai <cai@lca.pw>, Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Linux-MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Jason Gunthorpe <jgg@ziepe.ca>,
Dan Williams <dan.j.williams@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Michal Hocko <mhocko@kernel.org>,
Mark Rutland <Mark.Rutland@arm.com>,
Mark Brown <broonie@kernel.org>,
Steven Price <Steven.Price@arm.com>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Kees Cook <keescook@chromium.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Matthew Wilcox <willy@infradead.org>,
Sri Krishna chowdary <schowdary@nvidia.com>,
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Ingo Molnar <mingo@kernel.org>,
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linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
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Subject: Re: [PATCH V12] mm/debug: Add tests validating architecture page table helpers
Date: Tue, 28 Jan 2020 07:13:04 +0100 [thread overview]
Message-ID: <a7ba6d8a-6443-5994-6a34-2824aa9b054b@c-s.fr> (raw)
In-Reply-To: <016A776F-EFD9-4D2B-A3A9-788008617D95@lca.pw>
Le 28/01/2020 à 04:33, Qian Cai a écrit :
>
>
>> On Jan 27, 2020, at 10:06 PM, Anshuman Khandual <anshuman.khandual@arm.com> wrote:
>>
>>
>>
>> On 01/28/2020 07:41 AM, Qian Cai wrote:
>>>
>>>
>>>> On Jan 27, 2020, at 8:28 PM, Anshuman Khandual <Anshuman.Khandual@arm.com> wrote:
>>>>
>>>> This adds tests which will validate architecture page table helpers and
>>>> other accessors in their compliance with expected generic MM semantics.
>>>> This will help various architectures in validating changes to existing
>>>> page table helpers or addition of new ones.
>>>>
>>>> This test covers basic page table entry transformations including but not
>>>> limited to old, young, dirty, clean, write, write protect etc at various
>>>> level along with populating intermediate entries with next page table page
>>>> and validating them.
>>>>
>>>> Test page table pages are allocated from system memory with required size
>>>> and alignments. The mapped pfns at page table levels are derived from a
>>>> real pfn representing a valid kernel text symbol. This test gets called
>>>> right after page_alloc_init_late().
>>>>
>>>> This gets build and run when CONFIG_DEBUG_VM_PGTABLE is selected along with
>>>> CONFIG_VM_DEBUG. Architectures willing to subscribe this test also need to
>>>> select CONFIG_ARCH_HAS_DEBUG_VM_PGTABLE which for now is limited to x86 and
>>>> arm64. Going forward, other architectures too can enable this after fixing
>>>> build or runtime problems (if any) with their page table helpers.
>>
>> Hello Qian,
>>
>>>
>>> What’s the value of this block of new code? It only supports x86 and arm64
>>> which are supposed to be good now.
>>
>> We have been over the usefulness of this code many times before as the patch is
>> already in it's V12. Currently it is enabled on arm64, x86 (except PAE), arc and
>> ppc32. There are build time or runtime problems with other archs which prevent
>
> I am not sure if I care too much about arc and ppc32 which are pretty much legacy
> platforms.
>
>> enablement of this test (for the moment) but then the goal is to integrate all
>> of them going forward. The test not only validates platform's adherence to the
>> expected semantics from generic MM but also helps in keeping it that way during
>> code changes in future as well.
>
> Another option maybe to get some decent arches on board first before merging this
> thing, so it have more changes to catch regressions for developers who might run this.
>
ppc32 an indecent / legacy platform ? Are you kidying ?
Powerquicc II PRO for instance is fully supported by the manufacturer
and widely used in many small networking devices.
Christophe
next prev parent reply other threads:[~2020-01-28 6:13 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-28 1:27 [PATCH V12] mm/debug: Add tests validating architecture page table helpers Anshuman Khandual
2020-01-28 2:11 ` Qian Cai
2020-01-28 3:06 ` Anshuman Khandual
2020-01-28 3:33 ` Qian Cai
2020-01-28 4:57 ` Anshuman Khandual
2020-01-28 5:48 ` Qian Cai
2020-01-28 6:17 ` Christophe Leroy
2020-01-28 6:36 ` Qian Cai
2020-01-28 7:03 ` Anshuman Khandual
2020-01-28 7:07 ` Qian Cai
2020-01-28 6:13 ` Christophe Leroy [this message]
2020-01-28 7:12 ` Qian Cai
2020-01-28 11:58 ` Mark Brown
2020-01-28 12:09 ` Mike Rapoport
2020-01-29 22:20 ` Gerald Schaefer
2020-01-30 7:27 ` Mike Rapoport
2020-01-30 13:32 ` Anshuman Khandual
2020-01-28 17:47 ` Catalin Marinas
2020-01-28 19:07 ` Qian Cai
2020-01-29 10:36 ` Catalin Marinas
2020-01-29 11:09 ` Qian Cai
2020-01-28 17:05 ` Christophe Leroy
2020-01-30 13:04 ` Anshuman Khandual
2020-01-30 14:13 ` Christophe Leroy
2020-02-02 7:18 ` Anshuman Khandual
2020-02-02 8:31 ` Christophe Leroy
2020-02-02 11:26 ` Qian Cai
2020-02-03 15:14 ` Christophe Leroy
2020-02-03 15:48 ` Qian Cai
2020-02-02 8:26 ` Anshuman Khandual
2020-01-29 22:20 ` Gerald Schaefer
2020-01-30 13:11 ` Anshuman Khandual
2020-01-30 15:06 ` Anshuman Khandual
2020-02-10 15:37 ` Catalin Marinas
2020-02-12 9:42 ` Anshuman Khandual
2020-02-12 17:55 ` Gerald Schaefer
2020-02-13 2:15 ` Anshuman Khandual
2020-01-28 12:30 Qian Cai
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