On Mon, May 6, 2024 at 11:52 PM Bang Li <[email protected]> wrote:
>
> After the commit 19eaf44954df ("mm: thp: support allocation of anonymous
> multi-size THP"), it may need to batch update tlb of an address range
> through the update_mmu_tlb function. We can simplify this operation by
> adding the update_mmu_tlb_range function, which may also reduce the
> execution of some unnecessary code in some architectures.
>
> Signed-off-by: Bang Li <[email protected]>
> ---
> include/linux/pgtable.h | 8 ++++++++
> mm/memory.c | 4 +---
> 2 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
> index 18019f037bae..869bfe6054f1 100644
> --- a/include/linux/pgtable.h
> +++ b/include/linux/pgtable.h
> @@ -737,6 +737,14 @@ static inline void update_mmu_tlb(struct vm_area_struct *vma,
> #define __HAVE_ARCH_UPDATE_MMU_TLB
> #endif
>
> +#ifndef __HAVE_ARCH_UPDATE_MMU_TLB_RANGE
IIRC, the contemporary practice is to define a macro with the same name
as the function if it is being overridden.
Thanks,
Lance
> +static inline void update_mmu_tlb_range(struct vm_area_struct *vma,
> + unsigned long address, pte_t *ptep, unsigned int nr)
> +{
> +}
> +#define __HAVE_ARCH_UPDATE_MMU_TLB_RANGE
> +#endif
> +
> /*
> * Some architectures may be able to avoid expensive synchronization
> * primitives when modifications are made to PTE's which are already
> diff --git a/mm/memory.c b/mm/memory.c
> index eea6e4984eae..2d53e29cf76e 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -4421,7 +4421,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
> vm_fault_t ret = 0;
> int nr_pages = 1;
> pte_t entry;
> - int i;
>
> /* File mapping without ->vm_ops ? */
> if (vma->vm_flags & VM_SHARED)
> @@ -4491,8 +4490,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
> update_mmu_tlb(vma, addr, vmf->pte);
> goto release;
> } else if (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages)) {
> - for (i = 0; i < nr_pages; i++)
> - update_mmu_tlb(vma, addr + PAGE_SIZE * i, vmf->pte + i);
> + update_mmu_tlb_range(vma, addr, vmf->pte, nr_pages);
> goto release;
> }
>
> --
> 2.19.1.6.gb485710b
>
Hey Lance,
Thanks for taking time to review!
On 2024/5/7 0:07, Lance Yang wrote:
> On Mon, May 6, 2024 at 11:52 PM Bang Li <[email protected]> wrote:
>>
>> After the commit 19eaf44954df ("mm: thp: support allocation of anonymous
>> multi-size THP"), it may need to batch update tlb of an address range
>> through the update_mmu_tlb function. We can simplify this operation by
>> adding the update_mmu_tlb_range function, which may also reduce the
>> execution of some unnecessary code in some architectures.
>>
>> Signed-off-by: Bang Li <[email protected]>
>> ---
>> include/linux/pgtable.h | 8 ++++++++
>> mm/memory.c | 4 +---
>> 2 files changed, 9 insertions(+), 3 deletions(-)
>>
>> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
>> index 18019f037bae..869bfe6054f1 100644
>> --- a/include/linux/pgtable.h
>> +++ b/include/linux/pgtable.h
>> @@ -737,6 +737,14 @@ static inline void update_mmu_tlb(struct vm_area_struct *vma,
>> #define __HAVE_ARCH_UPDATE_MMU_TLB
>> #endif
>>
>> +#ifndef __HAVE_ARCH_UPDATE_MMU_TLB_RANGE
>
> IIRC, the contemporary practice is to define a macro with the same name
> as the function if it is being overridden.
The macro __HAVE_ARCH_UPDATE_MMU_TLB_RANGE defined here is aligned with
the macro __HAVE_ARCH_UPDATE_MMU_TLB corresponding to the update_mmu_tlb
function. IMO, it should be better to use my method in this case.
Thanks,
Bang
>
> Thanks,
> Lance
>
>> +static inline void update_mmu_tlb_range(struct vm_area_struct *vma,
>> + unsigned long address, pte_t *ptep, unsigned int nr)
>> +{
>> +}
>> +#define __HAVE_ARCH_UPDATE_MMU_TLB_RANGE
>> +#endif
>> +
>> /*
>> * Some architectures may be able to avoid expensive synchronization
>> * primitives when modifications are made to PTE's which are already
>> diff --git a/mm/memory.c b/mm/memory.c
>> index eea6e4984eae..2d53e29cf76e 100644
>> --- a/mm/memory.c
>> +++ b/mm/memory.c
>> @@ -4421,7 +4421,6 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
>> vm_fault_t ret = 0;
>> int nr_pages = 1;
>> pte_t entry;
>> - int i;
>>
>> /* File mapping without ->vm_ops ? */
>> if (vma->vm_flags & VM_SHARED)
>> @@ -4491,8 +4490,7 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf)
>> update_mmu_tlb(vma, addr, vmf->pte);
>> goto release;
>> } else if (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages)) {
>> - for (i = 0; i < nr_pages; i++)
>> - update_mmu_tlb(vma, addr + PAGE_SIZE * i, vmf->pte + i);
>> + update_mmu_tlb_range(vma, addr, vmf->pte, nr_pages);
>> goto release;
>> }
>>
>> --
>> 2.19.1.6.gb485710b
>>