Re: [PATCH 1/3] mm: define generic pudp_invalidate() implementation

[Jinjiang Tu <tujinjiang@huawei.com>]

在 2026/9/9 18:24, David Hildenbrand (Arm) 写道:
> On 9/9/26 11:00, Jinjiang Tu wrote:
>> x86 and riscv have identical pudp_invalidate() implementations. Move it to
>> mm/pgtable-generic.c with the __HAVE_ARCH_PUDP_INVALIDATE override guard.
>> PowerPC keeps its own implementation. In the later patch, arm64 will use
>> the generic implementation too.
>>
>> No functional change intended.
>>
>> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com>
>> ---
>>   arch/powerpc/include/asm/book3s/64/pgtable.h |  1 +
>>   arch/riscv/include/asm/pgtable.h             |  3 ---
>>   arch/riscv/mm/pgtable.c                      |  9 ---------
>>   arch/x86/include/asm/pgtable.h               |  3 ---
>>   arch/x86/mm/pgtable.c                        | 12 ------------
>>   include/linux/pgtable.h                      |  7 +++++++
>>   mm/pgtable-generic.c                         | 14 ++++++++++++++
>>   7 files changed, 22 insertions(+), 27 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/book3s/64/pgtable.h b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> index f4db7d7fbd5c..55d33c5537f1 100644
>> --- a/arch/powerpc/include/asm/book3s/64/pgtable.h
>> +++ b/arch/powerpc/include/asm/book3s/64/pgtable.h
>> @@ -1419,6 +1419,7 @@ static inline pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm,
>>   #define __HAVE_ARCH_PMDP_INVALIDATE
>>   extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
>>   			     pmd_t *pmdp);
>> +#define __HAVE_ARCH_PUDP_INVALIDATE
>>   extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
>>   			     pud_t *pudp);
>>   
>> diff --git a/arch/riscv/include/asm/pgtable.h b/arch/riscv/include/asm/pgtable.h
>> index 40b1ed4f3ea8..327fa378032b 100644
>> --- a/arch/riscv/include/asm/pgtable.h
>> +++ b/arch/riscv/include/asm/pgtable.h
>> @@ -1159,9 +1159,6 @@ static inline pud_t pud_mkinvalid(pud_t pud)
>>   	return __pud(pud_val(pud) & ~(_PAGE_PRESENT | _PAGE_PROT_NONE));
>>   }
>>   
>> -extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
>> -			     pud_t *pudp);
>> -
>>   static inline pud_t pud_modify(pud_t pud, pgprot_t newprot)
>>   {
>>   	return pte_pud(pte_modify(pud_pte(pud), newprot));
>> diff --git a/arch/riscv/mm/pgtable.c b/arch/riscv/mm/pgtable.c
>> index 9c4427d0b187..156e385e7db4 100644
>> --- a/arch/riscv/mm/pgtable.c
>> +++ b/arch/riscv/mm/pgtable.c
>> @@ -154,15 +154,6 @@ pmd_t pmdp_collapse_flush(struct vm_area_struct *vma,
>>   	return pmd;
>>   }
>>   
>> -pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
>> -		      pud_t *pudp)
>> -{
>> -	VM_WARN_ON_ONCE(!pud_present(*pudp));
>> -	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
>> -
>> -	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
>> -	return old;
>> -}
>>   #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>>   
>>   pte_t pte_mkwrite(pte_t pte, struct vm_area_struct *vma)
>> diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h
>> index d5f4917c1edc..97051c02385e 100644
>> --- a/arch/x86/include/asm/pgtable.h
>> +++ b/arch/x86/include/asm/pgtable.h
>> @@ -1387,9 +1387,6 @@ static inline pud_t pudp_establish(struct vm_area_struct *vma,
>>   extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
>>   				unsigned long address, pmd_t *pmdp);
>>   
>> -pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
>> -		      pud_t *pudp);
>> -
>>   /*
>>    * Page table pages are page-aligned.  The lower half of the top
>>    * level is used for userspace and the top half for the kernel.
>> diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
>> index cb03f5a2b243..0945908631dc 100644
>> --- a/arch/x86/mm/pgtable.c
>> +++ b/arch/x86/mm/pgtable.c
>> @@ -519,18 +519,6 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
>>   }
>>   #endif
>>   
>> -#if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \
>> -	defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)
>> -pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
>> -		     pud_t *pudp)
>> -{
>> -	VM_WARN_ON_ONCE(!pud_present(*pudp));
>> -	pud_t old = pudp_establish(vma, address, pudp, pud_mkinvalid(*pudp));
>> -	flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
>> -	return old;
>> -}
>> -#endif
>> -
>>   /**
>>    * reserve_top_address - Reserve a hole in the top of the kernel address space
>>    * @reserve: Size of hole to reserve
>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>> index 8c093c119e5a..32173005b087 100644
>> --- a/include/linux/pgtable.h
>> +++ b/include/linux/pgtable.h
>> @@ -1318,6 +1318,13 @@ extern pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma,
>>   				unsigned long address, pmd_t *pmdp);
>>   #endif
>>   
>> +#ifndef __HAVE_ARCH_PUDP_INVALIDATE
>> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
>> +extern pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
>> +			     pud_t *pudp);
> No "extern" please.

Will update it.

>
> Staring at this file, I do wonder why we are not smarter about combining blocks. E.g., here simply:'

Do you mean merging all #ifdef CONFIG_TRANSPARENT_HUGEPAGE blocks? There are many of them scattered
across include/linux/pgtable.h and arch/arm64/include/asm/pgtable.h. They are intentionally kept
separate to group the PTE, PMD, and PUD level variants of the same operation together. For example,
ptep_set_access_flags, pmdp_set_access_flags, and pudp_set_access_flags are placed adjacently.

>
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index e3c8ab96941c5..8c9fe3bf580d4 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -1229,9 +1229,9 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm,
>   }
>   #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>   #endif
> -#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
> -#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
>   #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> +#ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT
>   static inline void pudp_set_wrprotect(struct mm_struct *mm,
>                                        unsigned long address, pud_t *pudp)
>   {
> @@ -1245,9 +1245,13 @@ static inline void pudp_set_wrprotect(struct mm_struct *mm,
>   {
>          BUILD_BUG();
>   }
> -#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
> -#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
>   #endif
> +#ifndef __HAVE_ARCH_PUDP_INVALIDATE
> +pud_t pudp_invalidate(struct vm_area_struct *vma, unsigned long address,
> +               pud_t *pudp);
> +#endif
> +#endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
> +#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
>
>> +#endif
>> +#endif
>> +
>>   #ifndef __HAVE_ARCH_PTE_SAME
>>   static inline int pte_same(pte_t pte_a, pte_t pte_b)
>>   {
>> diff --git a/mm/pgtable-generic.c b/mm/pgtable-generic.c
>> index b91b1a98029c..ac1175d9a59a 100644
>> --- a/mm/pgtable-generic.c
>> +++ b/mm/pgtable-generic.c
>> @@ -217,6 +217,20 @@ pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
>>   }
>>   #endif
>>   
>> +#ifndef __HAVE_ARCH_PUDP_INVALIDATE
>> +#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
> I'd revert these and similarly see if they can be combined somehow (likely combining with
> pudp_huge_clear_flush is harder as we are quite inconsistent with it, gluing it to
> __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH).
>
> Which raises the question whether we could also piggy-back on __HAVE_ARCH_PMDP_SET_WRPROTECT
> (I suspect no without a closer look.)
>