On Mon, Jul 31, 2023 at 4:14 PM Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> wrote:
>
> It is better to use huge_page_size() for hugepage(HugeTLB) instead of
> PAGE_SIZE for stride, which has been done in flush_pmd/pud_tlb_range(),
> it could reduce the loop in __flush_tlb_range().
>
> Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/tlbflush.h | 21 +++++++++++----------
> 1 file changed, 11 insertions(+), 10 deletions(-)
>
> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> index 412a3b9a3c25..25e35e6f8093 100644
> --- a/arch/arm64/include/asm/tlbflush.h
> +++ b/arch/arm64/include/asm/tlbflush.h
> @@ -360,16 +360,17 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
> dsb(ish);
> }
>
> -static inline void flush_tlb_range(struct vm_area_struct *vma,
> - unsigned long start, unsigned long end)
> -{
> - /*
> - * We cannot use leaf-only invalidation here, since we may be invalidating
> - * table entries as part of collapsing hugepages or moving page tables.
> - * Set the tlb_level to 0 because we can not get enough information here.
> - */
> - __flush_tlb_range(vma, start, end, PAGE_SIZE, false, 0);
> -}
> +/*
> + * We cannot use leaf-only invalidation here, since we may be invalidating
> + * table entries as part of collapsing hugepages or moving page tables.
> + * Set the tlb_level to 0 because we can not get enough information here.
> + */
> +#define flush_tlb_range(vma, start, end) \
> + __flush_tlb_range(vma, start, end, \
> + ((vma)->vm_flags & VM_HUGETLB) \
> + ? huge_page_size(hstate_vma(vma)) \
> + : PAGE_SIZE, false, 0)
> +
seems like a good idea.
I wonder if a better implementation will be MMU_GATHER_PAGE_SIZE, in this case,
we are going to support stride for other large folios as well, such as thp.
>
> static inline void flush_tlb_kernel_range(unsigned long start, unsigned long end)
> {
> --
> 2.41.0
>
Thanks
Barry
