Re: [PATCH] mm: Merge pte_mkhuge() call into arch_make_huge_pte()

From: Mike Rapoport <rppt@kernel.org>
To: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>,
	"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Paul Mackerras <paulus@samba.org>,
	Catalin Marinas <catalin.marinas@arm.com>,
	"sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Will Deacon <will@kernel.org>,
	"David S. Miller" <davem@davemloft.net>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	Mike Kravetz <mike.kravetz@oracle.com>
Subject: Re: [PATCH] mm: Merge pte_mkhuge() call into arch_make_huge_pte()
Date: Wed, 2 Feb 2022 09:37:41 +0200	[thread overview]
Message-ID: <Yfo0xR30H5jf3BsN@kernel.org> (raw)
In-Reply-To: <76605ef1-f2fe-8682-1eb7-2323f0b9bbaa@csgroup.eu>

On Wed, Feb 02, 2022 at 06:25:31AM +0000, Christophe Leroy wrote:
> 
> 
> Le 02/02/2022 à 07:18, Mike Rapoport a écrit :
> > On Wed, Feb 02, 2022 at 11:08:06AM +0530, Anshuman Khandual wrote:
> >> Each call into pte_mkhuge() is invariably followed by arch_make_huge_pte().
> >> Instead arch_make_huge_pte() can accommodate pte_mkhuge() at the beginning.
> >> This updates generic fallback stub for arch_make_huge_pte() and available
> >> platforms definitions. This makes huge pte creation much cleaner and easier
> >> to follow.
> > 
> > Won't it break architectures that don't define arch_make_huge_pte()?
> 
> It shouldn't, see below

Right, overlooked that.

> >> diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
> >> index d1897a69c540..52c462390aee 100644
> >> --- a/include/linux/hugetlb.h
> >> +++ b/include/linux/hugetlb.h
> >> @@ -754,7 +754,7 @@ static inline void arch_clear_hugepage_flags(struct page *page) { }
> >>   static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift,
> >>   				       vm_flags_t flags)
> >>   {
> >> -	return entry;
> >> +	return pte_mkhuge(entry);
> >>   }
> >>   #endif
> >>   

-- 
Sincerely yours,
Mike.