Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers

From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Christophe Leroy <christophe.leroy@c-s.fr>,
	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>,
	Dave Hansen <dave.hansen@intel.com>,
	Russell King - ARM Linux <linux@armlinux.org.uk>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Paul Mackerras <paulus@samba.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	"David S. Miller" <davem@davemloft.net>,
	Vineet Gupta <vgupta@synopsys.com>,
	James Hogan <jhogan@kernel.org>,
	Paul Burton <paul.burton@mips.com>,
	Ralf Baechle <ralf@linux-mips.org>,
	Gerald Schaefer <gerald.schaefer@de.ibm.com>,
	linux-snps-arc@lists.infradead.org, linux-mips@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
	linux-sh@vger.kernel.org, sparclinux@vger.kernel.org,
	x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 2/2] mm/pgtable/debug: Add test validating architecture page table helpers
Date: Fri, 13 Sep 2019 12:13:05 +0300	[thread overview]
Message-ID: <20190913091305.rkds4f3fqv3yjhjy@box> (raw)
In-Reply-To: <502c497a-9bf1-7d2e-95f2-cfebcd9cf1d9@arm.com>

On Fri, Sep 13, 2019 at 02:32:04PM +0530, Anshuman Khandual wrote:
> 
> On 09/12/2019 10:44 PM, Christophe Leroy wrote:
> > 
> > 
> > Le 12/09/2019 à 08:02, Anshuman Khandual a écrit :
> >> This adds a test module which will validate architecture page table helpers
> >> and accessors regarding compliance with generic MM semantics expectations.
> >> This will help various architectures in validating changes to the existing
> >> page table helpers or addition of new ones.
> >>
> >> Test page table and memory pages creating it's entries at various level are
> >> all allocated from system memory with required alignments. If memory pages
> >> with required size and alignment could not be allocated, then all depending
> >> individual tests are skipped.
> >>
> > 
> > [...]
> > 
> >>
> >> Suggested-by: Catalin Marinas <catalin.marinas@arm.com>
> >> Signed-off-by: Anshuman Khandual <anshuman.khandual@arm.com>
> >> ---
> >>   arch/x86/include/asm/pgtable_64_types.h |   2 +
> >>   mm/Kconfig.debug                        |  14 +
> >>   mm/Makefile                             |   1 +
> >>   mm/arch_pgtable_test.c                  | 429 ++++++++++++++++++++++++
> >>   4 files changed, 446 insertions(+)
> >>   create mode 100644 mm/arch_pgtable_test.c
> >>
> >> diff --git a/arch/x86/include/asm/pgtable_64_types.h b/arch/x86/include/asm/pgtable_64_types.h
> >> index 52e5f5f2240d..b882792a3999 100644
> >> --- a/arch/x86/include/asm/pgtable_64_types.h
> >> +++ b/arch/x86/include/asm/pgtable_64_types.h
> >> @@ -40,6 +40,8 @@ static inline bool pgtable_l5_enabled(void)
> >>   #define pgtable_l5_enabled() 0
> >>   #endif /* CONFIG_X86_5LEVEL */
> >>   +#define mm_p4d_folded(mm) (!pgtable_l5_enabled())
> >> +
> > 
> > This is specific to x86, should go in a separate patch.
> 
> Thought about it but its just a single line. Kirill suggested this in the
> previous version. There is a generic fallback definition but s390 has it's
> own. This change overrides the generic one for x86 probably as a fix or as
> an improvement. Kirill should be able to help classify it in which case it
> can be a separate patch.

I don't think it worth a separate patch.

-- 
 Kirill A. Shutemov