On Thu, Jul 27, 2023 at 08:55:53PM +0200, Alexandre Ghiti wrote:
> This function used to simply flush the whole tlb of all harts, be more
> subtile and try to only flush the range.
>
> The problem is that we can only use PAGE_SIZE as stride since we don't know
> the size of the underlying mapping and then this function will be improved
> only if the size of the region to flush is < threshold * PAGE_SIZE.
>
> Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
> ---
> arch/riscv/include/asm/tlbflush.h | 11 +++++-----
> arch/riscv/mm/tlbflush.c | 35 +++++++++++++++++++++++--------
> 2 files changed, 32 insertions(+), 14 deletions(-)
>
> diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
> index f5c4fb0ae642..7426fdcd8ec5 100644
> --- a/arch/riscv/include/asm/tlbflush.h
> +++ b/arch/riscv/include/asm/tlbflush.h
> @@ -37,6 +37,7 @@ void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
> void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr);
> void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end);
> +void flush_tlb_kernel_range(unsigned long start, unsigned long end);
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> #define __HAVE_ARCH_FLUSH_PMD_TLB_RANGE
> void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> @@ -53,15 +54,15 @@ static inline void flush_tlb_range(struct vm_area_struct *vma,
> local_flush_tlb_all();
> }
>
> -#define flush_tlb_mm(mm) flush_tlb_all()
> -#define flush_tlb_mm_range(mm, start, end, page_size) flush_tlb_all()
> -#endif /* !CONFIG_SMP || !CONFIG_MMU */
> -
> /* Flush a range of kernel pages */
> static inline void flush_tlb_kernel_range(unsigned long start,
> unsigned long end)
> {
> - flush_tlb_all();
> + local_flush_tlb_all();
> }
>
> +#define flush_tlb_mm(mm) flush_tlb_all()
> +#define flush_tlb_mm_range(mm, start, end, page_size) flush_tlb_all()
> +#endif /* !CONFIG_SMP || !CONFIG_MMU */
> +
> #endif /* _ASM_RISCV_TLBFLUSH_H */
> diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
> index 8017d2130e27..96aeacb269d5 100644
> --- a/arch/riscv/mm/tlbflush.c
> +++ b/arch/riscv/mm/tlbflush.c
> @@ -117,18 +117,27 @@ static void __flush_tlb_range(struct mm_struct *mm, unsigned long start,
> unsigned long size, unsigned long stride)
> {
> struct flush_tlb_range_data ftd;
> - struct cpumask *cmask = mm_cpumask(mm);
> - unsigned int cpuid;
> + struct cpumask *cmask, full_cmask;
> bool broadcast;
>
> - if (cpumask_empty(cmask))
> - return;
> + if (mm) {
> + unsigned int cpuid;
> +
> + cmask = mm_cpumask(mm);
> + if (cpumask_empty(cmask))
> + return;
> +
> + cpuid = get_cpu();
> + /* check if the tlbflush needs to be sent to other CPUs */
> + broadcast = cpumask_any_but(cmask, cpuid) < nr_cpu_ids;
> + } else {
> + cpumask_setall(&full_cmask);
> + cmask = &full_cmask;
> + broadcast = true;
> + }
>
> - cpuid = get_cpu();
> - /* check if the tlbflush needs to be sent to other CPUs */
> - broadcast = cpumask_any_but(cmask, cpuid) < nr_cpu_ids;
> if (static_branch_unlikely(&use_asid_allocator)) {
> - unsigned long asid = atomic_long_read(&mm->context.id) & asid_mask;
> + unsigned long asid = mm ? atomic_long_read(&mm->context.id) & asid_mask : 0;
>
> if (broadcast) {
> if (riscv_use_ipi_for_rfence()) {
> @@ -162,7 +171,8 @@ static void __flush_tlb_range(struct mm_struct *mm, unsigned long start,
> }
> }
>
> - put_cpu();
> + if (mm)
> + put_cpu();
> }
>
> void flush_tlb_mm(struct mm_struct *mm)
> @@ -194,6 +204,13 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
> __flush_tlb_range(vma->vm_mm,
> start, end - start, 1 << stride_shift);
> }
> +
> +void flush_tlb_kernel_range(unsigned long start,
> + unsigned long end)
No need to wrap this line.
> +{
> + __flush_tlb_range(NULL, start, end, PAGE_SIZE);
> +}
> +
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end)
> --
> 2.39.2
>
Otherwise,
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
Thanks,
drew
