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Date: Tue, 12 Nov 2019 07:29:51 +0100
From: Ingo Molnar <mingo@kernel.org>
Subject: Re: [PATCH V9] mm/debug: Add tests validating architecture page
 table helpers
Message-ID: <20191112062951.GA100264@gmail.com>
References: <1573532326-24084-1-git-send-email-anshuman.khandual@arm.com>
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To: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: 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>, "Kirill A . Shutemov" <kirill@shutemov.name>, Gerald Schaefer <gerald.schaefer@de.ibm.com>, Christophe Leroy <christophe.leroy@c-s.fr>, 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


* Anshuman Khandual <anshuman.khandual@arm.com> wrote:

> +config DEBUG_VM_PGTABLE
> +	bool "Debug arch page table for semantics compliance"
> +	depends on MMU
> +	depends on DEBUG_VM
> +	depends on ARCH_HAS_DEBUG_VM_PGTABLE
> +	help
> +	  This option provides a debug method which can be used to test
> +	  architecture page table helper functions on various platforms in
> +	  verifying if they comply with expected generic MM semantics. This
> +	  will help architecture code in making sure that any changes or
> +	  new additions of these helpers still conform to expected
> +	  semantics of the generic MM.
> +
> +	  If unsure, say N.

Since CONFIG_DEBUG_VM is generally disabled in distro kernel packages, 
why not make this 'default y' to maximize testing coverage? The code size 
increase should be minimal, and DEBUG_VM increases size anyway.

Other than that this looks good to me:

  Reviewed-by: Ingo Molnar <mingo@kernel.org>

Thanks,

	Ingo