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Mon, 13 Apr 2026 08:32:39 -0700 (PDT) X-Received: by 2002:a05:620a:318b:b0:8d0:27b8:fb7 with SMTP id af79cd13be357-8ddcff98825mr2066528585a.46.1776094358967; Mon, 13 Apr 2026 08:32:38 -0700 (PDT) Received: from [192.168.2.110] ([69.159.169.238]) by smtp.gmail.com with ESMTPSA id af79cd13be357-8ddb9930572sm882765185a.45.2026.04.13.08.32.38 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 13 Apr 2026 08:32:38 -0700 (PDT) Message-ID: <056d8383-d373-436b-8841-6350425c52eb@redhat.com> Date: Mon, 13 Apr 2026 11:32:27 -0400 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 07/10] treewide: rename has_transparent_hugepage() to arch_has_pmd_leaves() From: Luiz Capitulino To: Zi Yan Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, david@kernel.org, baolin.wang@linux.alibaba.com, ryan.roberts@arm.com, akpm@linux-foundation.org, lorenzo.stoakes@oracle.com References: <4f640655f26b4cc2056a62bebfd570686dd6dc3c.1775679721.git.luizcap@redhat.com> <315f7856-82aa-4566-8c16-1d96314b235c@redhat.com> Content-Language: en-US, en-CA In-Reply-To: <315f7856-82aa-4566-8c16-1d96314b235c@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2026-04-09 15:43, Luiz Capitulino wrote: > On 2026-04-09 11:41, Zi Yan wrote: >> On 8 Apr 2026, at 16:23, Luiz Capitulino wrote: >> >>> Now that all the has_transparent_hugepage() callers have been converted >>> to pgtable_has_pmd_leaves(), rename has_transparent_hugepage() to >>> arch_has_pmd_leaves() since that's what the helper checks for. >>> >>> arch_has_pmd_leaves() is supposed to be called only by >>> init_arch_has_pmd_leaves(). The remaining exception is hugepage_init() >>> which will be converted in a future commit. >>> >>> Signed-off-by: Luiz Capitulino >>> --- >>> arch/mips/include/asm/pgtable.h | 4 ++-- >>> arch/mips/mm/tlb-r4k.c | 4 ++-- >>> arch/powerpc/include/asm/book3s/64/hash-4k.h | 2 +- >>> arch/powerpc/include/asm/book3s/64/hash-64k.h | 2 +- >>> arch/powerpc/include/asm/book3s/64/pgtable.h | 10 +++++----- >>> arch/powerpc/include/asm/book3s/64/radix.h | 2 +- >>> arch/powerpc/mm/book3s64/hash_pgtable.c | 4 ++-- >>> arch/s390/include/asm/pgtable.h | 4 ++-- >>> arch/x86/include/asm/pgtable.h | 4 ++-- >>> include/linux/pgtable.h | 4 ++-- >>> mm/huge_memory.c | 2 +- >>> mm/memory.c | 2 +- >>> 12 files changed, 22 insertions(+), 22 deletions(-) >>> >>> diff --git a/arch/mips/include/asm/pgtable.h b/arch/mips/include/asm/pgtable.h >>> index fa7b935f947c..a97b788315e2 100644 >>> --- a/arch/mips/include/asm/pgtable.h >>> +++ b/arch/mips/include/asm/pgtable.h >>> @@ -615,8 +615,8 @@ unsigned long io_remap_pfn_range_pfn(unsigned long pfn, unsigned long size); >>> /* We don't have hardware dirty/accessed bits, generic_pmdp_establish is fine.*/ >>> #define pmdp_establish generic_pmdp_establish >>> >>> -#define has_transparent_hugepage has_transparent_hugepage >>> -extern int has_transparent_hugepage(void); >>> +#define arch_has_pmd_leaves arch_has_pmd_leaves >>> +extern int arch_has_pmd_leaves(void); >>> >>> static inline int pmd_trans_huge(pmd_t pmd) >>> { >>> diff --git a/arch/mips/mm/tlb-r4k.c b/arch/mips/mm/tlb-r4k.c >>> index 24fe85fa169d..c423b5784337 100644 >>> --- a/arch/mips/mm/tlb-r4k.c >>> +++ b/arch/mips/mm/tlb-r4k.c >>> @@ -434,7 +434,7 @@ void add_wired_entry(unsigned long entrylo0, unsigned long entrylo1, >>> >>> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >>> >>> -int has_transparent_hugepage(void) >>> +int arch_has_pmd_leaves(void) >>> { >>> static unsigned int mask = -1; >>> >>> @@ -450,7 +450,7 @@ int has_transparent_hugepage(void) >>> } >>> return mask == PM_HUGE_MASK; >>> } >>> -EXPORT_SYMBOL(has_transparent_hugepage); >>> +EXPORT_SYMBOL(arch_has_pmd_leaves); >>> >>> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ >>> >>> diff --git a/arch/powerpc/include/asm/book3s/64/hash-4k.h b/arch/powerpc/include/asm/book3s/64/hash-4k.h >>> index 8e5bd9902bed..6744c2287199 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/hash-4k.h >>> +++ b/arch/powerpc/include/asm/book3s/64/hash-4k.h >>> @@ -165,7 +165,7 @@ extern void hash__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, >>> extern pgtable_t hash__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); >>> extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm, >>> unsigned long addr, pmd_t *pmdp); >>> -extern int hash__has_transparent_hugepage(void); >>> +extern int hash__arch_has_pmd_leaves(void); >>> #endif >>> >>> #endif /* !__ASSEMBLER__ */ >>> diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h >>> index 7deb3a66890b..9392aba5e5dc 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h >>> +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h >>> @@ -278,7 +278,7 @@ extern void hash__pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, >>> extern pgtable_t hash__pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); >>> extern pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm, >>> unsigned long addr, pmd_t *pmdp); >>> -extern int hash__has_transparent_hugepage(void); >>> +extern int hash__arch_has_pmd_leaves(void); >>> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ >>> >>> #endif /* __ASSEMBLER__ */ >>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h >>> index 1a91762b455d..e4d9b884af5c 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h >>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h >>> @@ -1121,14 +1121,14 @@ static inline void update_mmu_cache_pud(struct vm_area_struct *vma, >>> { >>> } >>> >>> -extern int hash__has_transparent_hugepage(void); >>> -static inline int has_transparent_hugepage(void) >>> +extern int hash__arch_has_pmd_leaves(void); >>> +static inline int arch_has_pmd_leaves(void) >>> { >>> if (radix_enabled()) >>> - return radix__has_transparent_hugepage(); >>> - return hash__has_transparent_hugepage(); >>> + return radix__arch_has_pmd_leaves(); >>> + return hash__arch_has_pmd_leaves(); >>> } >>> -#define has_transparent_hugepage has_transparent_hugepage >>> +#define arch_has_pmd_leaves arch_has_pmd_leaves >>> >>> static inline int has_transparent_pud_hugepage(void) >>> { >>> diff --git a/arch/powerpc/include/asm/book3s/64/radix.h b/arch/powerpc/include/asm/book3s/64/radix.h >>> index da954e779744..c884a119cbd9 100644 >>> --- a/arch/powerpc/include/asm/book3s/64/radix.h >>> +++ b/arch/powerpc/include/asm/book3s/64/radix.h >>> @@ -298,7 +298,7 @@ extern pmd_t radix__pmdp_huge_get_and_clear(struct mm_struct *mm, >>> pud_t radix__pudp_huge_get_and_clear(struct mm_struct *mm, >>> unsigned long addr, pud_t *pudp); >>> >>> -static inline int radix__has_transparent_hugepage(void) >>> +static inline int radix__arch_has_pmd_leaves(void) >>> { >>> /* For radix 2M at PMD level means thp */ >>> if (mmu_psize_defs[MMU_PAGE_2M].shift == PMD_SHIFT) >>> diff --git a/arch/powerpc/mm/book3s64/hash_pgtable.c b/arch/powerpc/mm/book3s64/hash_pgtable.c >>> index ac2a24d15d2e..f7933c52cca9 100644 >>> --- a/arch/powerpc/mm/book3s64/hash_pgtable.c >>> +++ b/arch/powerpc/mm/book3s64/hash_pgtable.c >>> @@ -370,7 +370,7 @@ pmd_t hash__pmdp_huge_get_and_clear(struct mm_struct *mm, >>> return old_pmd; >>> } >>> >>> -int hash__has_transparent_hugepage(void) >>> +int hash__arch_has_pmd_leaves(void) >>> { >>> >>> if (!mmu_has_feature(MMU_FTR_16M_PAGE)) >>> @@ -399,7 +399,7 @@ int hash__has_transparent_hugepage(void) >>> >>> return 1; >>> } >>> -EXPORT_SYMBOL_GPL(hash__has_transparent_hugepage); >>> +EXPORT_SYMBOL_GPL(hash__arch_has_pmd_leaves); >>> >>> #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ >>> >>> diff --git a/arch/s390/include/asm/pgtable.h b/arch/s390/include/asm/pgtable.h >>> index 1c3c3be93be9..e638d914fbad 100644 >>> --- a/arch/s390/include/asm/pgtable.h >>> +++ b/arch/s390/include/asm/pgtable.h >>> @@ -1776,8 +1776,8 @@ static inline int pmd_trans_huge(pmd_t pmd) >>> return pmd_leaf(pmd); >>> } >>> >>> -#define has_transparent_hugepage has_transparent_hugepage >>> -static inline int has_transparent_hugepage(void) >>> +#define arch_has_pmd_leaves arch_has_pmd_leaves >>> +static inline int arch_has_pmd_leaves(void) >>> { >>> return cpu_has_edat1() ? 1 : 0; >>> } >>> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h >>> index 1662c5a8f445..8fe95270b713 100644 >>> --- a/arch/x86/include/asm/pgtable.h >>> +++ b/arch/x86/include/asm/pgtable.h >>> @@ -314,8 +314,8 @@ static inline int pud_trans_huge(pud_t pud) >>> } >>> #endif >>> >>> -#define has_transparent_hugepage has_transparent_hugepage >>> -static inline int has_transparent_hugepage(void) >>> +#define arch_has_pmd_leaves arch_has_pmd_leaves >>> +static inline int arch_has_pmd_leaves(void) >>> { >>> return boot_cpu_has(X86_FEATURE_PSE); >>> } >>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >>> index c4c5282f795c..4b52a3abeab5 100644 >>> --- a/include/linux/pgtable.h >>> +++ b/include/linux/pgtable.h >>> @@ -2222,8 +2222,8 @@ static inline void __init init_arch_has_pmd_leaves(void) { } >>> #endif >>> #endif >>> >>> -#ifndef has_transparent_hugepage >>> -#define has_transparent_hugepage() IS_BUILTIN(CONFIG_TRANSPARENT_HUGEPAGE) >>> +#ifndef arch_has_pmd_leaves >>> +#define arch_has_pmd_leaves() IS_BUILTIN(CONFIG_TRANSPARENT_HUGEPAGE) >> >> Should this be >> #define arch_has_pmd_leaves() 1 >> ? >> >> Since all has_transparent_hugepage() is converted >> to IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) && pgtable_has_pmd_leaves() >> and pgtable_has_pmd_leaves() is basically arch_has_pmd_leaves(). >> The IS_ENABLED() is the same as IS_BUILTIN() here. >> >> Before this patch, if an arch does not define has_transparent_hugepage, >> has_transparent_hugepage() basically means the arch supports PMD leaves >> and software controls the availability of THP. Now you rename it to >> arch_has_pmd_leaves() and setting it to 1 reflects its actual semantics. > > Yes, you're right that the intended future semantics is: if an arch > doesn't define arch_has_pmd_leaves() then the kernel assumes it supports > PMD pages. > > I originally kept arch_has_pmd_leaves() tied to THP because I was afraid > of breaking the current callers who want to use PMD pages with THP. But, > as you say, they should all be checking for > IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) now. > > I'll look into implementing your suggestion for v4. In taking a second look at this, I realized that a better default should be: #define arch_has_pmd_leaves() IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE) Since archs defining CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE should support PMD pages. This is also consistent with has_transparent_pud_hugepage().