Re: [PATCH v3 2/4] mm: Support tlbbatch flush for a range of PTEs

Kefeng Wang
2025-01-16T08:32:34Z

On 2025/1/15 11:38, Barry Song wrote:
> From: Barry Song <v-songbaohua@oppo.com>
>
> This patch lays the groundwork for supporting batch PTE unmapping in
> try_to_unmap_one(). It introduces range handling for TLB batch flushing,
> with the range currently set to the size of PAGE_SIZE.
>
> The function __flush_tlb_range_nosync() is architecture-specific and is
> only used within arch/arm64. This function requires the mm structure
> instead of the vma structure. To allow its reuse by
> arch_tlbbatch_add_pending(), which operates with mm but not vma, this
> patch modifies the argument of __flush_tlb_range_nosync() to take mm
> as its parameter.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: Anshuman Khandual <anshuman.khandual@arm.com>
> Cc: Ryan Roberts <ryan.roberts@arm.com>
> Cc: Shaoqin Huang <shahuang@redhat.com>
> Cc: Gavin Shan <gshan@redhat.com>
> Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Lance Yang <ioworker0@gmail.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: Yosry Ahmed <yosryahmed@google.com>
> Cc: Paul Walmsley <paul.walmsley@sifive.com>
> Cc: Palmer Dabbelt <palmer@dabbelt.com>
> Cc: Albert Ou <aou@eecs.berkeley.edu>
> Cc: Yicong Yang <yangyicong@hisilicon.com>
> Signed-off-by: Barry Song <v-songbaohua@oppo.com>
> Acked-by: Will Deacon <will@kernel.org>
> ---
> arch/arm64/include/asm/tlbflush.h | 25 +++++++++++++------------
> arch/arm64/mm/contpte.c | 2 +-
> arch/riscv/include/asm/tlbflush.h | 5 +++--
> arch/riscv/mm/tlbflush.c | 5 +++--
> arch/x86/include/asm/tlbflush.h | 5 +++--
> mm/rmap.c | 12 +++++++-----
> 6 files changed, 30 insertions(+), 24 deletions(-)
>
> diff --git a/arch/arm64/include/asm/tlbflush.h b/arch/arm64/include/asm/tlbflush.h
> index bc94e036a26b..98fbc8df7cf3 100644
> --- a/arch/arm64/include/asm/tlbflush.h
> +++ b/arch/arm64/include/asm/tlbflush.h
> @@ -322,13 +322,6 @@ static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
> return true;
> }
>
> -static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
> - struct mm_struct *mm,
> - unsigned long uaddr)
> -{
> - __flush_tlb_page_nosync(mm, uaddr);
> -}
> -
> /*
> * If mprotect/munmap/etc occurs during TLB batched flushing, we need to
> * synchronise all the TLBI issued with a DSB to avoid the race mentioned in
> @@ -448,7 +441,7 @@ static inline bool __flush_tlb_range_limit_excess(unsigned long start,
> return false;
> }
>
> -static inline void __flush_tlb_range_nosync(struct vm_area_struct *vma,
> +static inline void __flush_tlb_range_nosync(struct mm_struct *mm,
> unsigned long start, unsigned long end,
> unsigned long stride, bool last_level,
> int tlb_level)
> @@ -460,12 +453,12 @@ static inline void __flush_tlb_range_nosync(struct vm_area_struct *vma,
> pages = (end - start) >> PAGE_SHIFT;
>
> if (__flush_tlb_range_limit_excess(start, end, pages, stride)) {
> - flush_tlb_mm(vma->vm_mm);
> + flush_tlb_mm(mm);
> return;
> }
>
> dsb(ishst);
> - asid = ASID(vma->vm_mm);
> + asid = ASID(mm);
>
> if (last_level)
> __flush_tlb_range_op(vale1is, start, pages, stride, asid,
> @@ -474,7 +467,7 @@ static inline void __flush_tlb_range_nosync(struct vm_area_struct *vma,
> __flush_tlb_range_op(vae1is, start, pages, stride, asid,
> tlb_level, true, lpa2_is_enabled());
>
> - mmu_notifier_arch_invalidate_secondary_tlbs(vma->vm_mm, start, end);
> + mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
> }
>
> static inline void __flush_tlb_range(struct vm_area_struct *vma,
> @@ -482,7 +475,7 @@ static inline void __flush_tlb_range(struct vm_area_struct *vma,
> unsigned long stride, bool last_level,
> int tlb_level)
> {
> - __flush_tlb_range_nosync(vma, start, end, stride,
> + __flush_tlb_range_nosync(vma->vm_mm, start, end, stride,
> last_level, tlb_level);
> dsb(ish);
> }
> @@ -533,6 +526,14 @@ static inline void __flush_tlb_kernel_pgtable(unsigned long kaddr)
> dsb(ish);
> isb();
> }
> +
> +static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
> + struct mm_struct *mm,
> + unsigned long start,
> + unsigned long end)

Only one line for arguments, same for other functions，

Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>

> +{
> + __flush_tlb_range_nosync(mm, start, end, PAGE_SIZE, true, 3);
> +}
> #endif
>
> #endif
> diff --git a/arch/arm64/mm/contpte.c b/arch/arm64/mm/contpte.c
> index 55107d27d3f8..bcac4f55f9c1 100644
> --- a/arch/arm64/mm/contpte.c
> +++ b/arch/arm64/mm/contpte.c
> @@ -335,7 +335,7 @@ int contpte_ptep_clear_flush_young(struct vm_area_struct *vma,
> * eliding the trailing DSB applies here.
> */
> addr = ALIGN_DOWN(addr, CONT_PTE_SIZE);
> - __flush_tlb_range_nosync(vma, addr, addr + CONT_PTE_SIZE,
> + __flush_tlb_range_nosync(vma->vm_mm, addr, addr + CONT_PTE_SIZE,
> PAGE_SIZE, true, 3);
> }
>
> diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
> index 72e559934952..e4c533691a7d 100644
> --- a/arch/riscv/include/asm/tlbflush.h
> +++ b/arch/riscv/include/asm/tlbflush.h
> @@ -60,8 +60,9 @@ void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
>
> bool arch_tlbbatch_should_defer(struct mm_struct *mm);
> void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
> - struct mm_struct *mm,
> - unsigned long uaddr);
> + struct mm_struct *mm,
> + unsigned long start,
> + unsigned long end);
> void arch_flush_tlb_batched_pending(struct mm_struct *mm);
> void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
>
> diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
> index 9b6e86ce3867..6d6e8e7cc576 100644
> --- a/arch/riscv/mm/tlbflush.c
> +++ b/arch/riscv/mm/tlbflush.c
> @@ -186,8 +186,9 @@ bool arch_tlbbatch_should_defer(struct mm_struct *mm)
> }
>
> void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
> - struct mm_struct *mm,
> - unsigned long uaddr)
> + struct mm_struct *mm,
> + unsigned long start,
> + unsigned long end)
> {
> cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm));
> }
> diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
> index 69e79fff41b8..2b511972d008 100644
> --- a/arch/x86/include/asm/tlbflush.h
> +++ b/arch/x86/include/asm/tlbflush.h
> @@ -278,8 +278,9 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
> }
>
> static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
> - struct mm_struct *mm,
> - unsigned long uaddr)
> + struct mm_struct *mm,
> + unsigned long start,
> + unsigned long end)
> {
> inc_mm_tlb_gen(mm);
> cpumask_or(&batch->cpumask, &batch->cpumask, mm_cpumask(mm));
> diff --git a/mm/rmap.c b/mm/rmap.c
> index de6b8c34e98c..abeb9fcec384 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -672,7 +672,8 @@ void try_to_unmap_flush_dirty(void)
> (TLB_FLUSH_BATCH_PENDING_MASK / 2)
>
> static void set_tlb_ubc_flush_pending(struct mm_struct *mm, pte_t pteval,
> - unsigned long uaddr)
> + unsigned long start,
> + unsigned long end)
> {
> struct tlbflush_unmap_batch *tlb_ubc = &current->tlb_ubc;
> int batch;
> @@ -681,7 +682,7 @@ static void set_tlb_ubc_flush_pending(struct mm_struct *mm, pte_t pteval,
> if (!pte_accessible(mm, pteval))
> return;
>
> - arch_tlbbatch_add_pending(&tlb_ubc->arch, mm, uaddr);
> + arch_tlbbatch_add_pending(&tlb_ubc->arch, mm, start, end);
> tlb_ubc->flush_required = true;
>
> /*
> @@ -757,7 +758,8 @@ void flush_tlb_batched_pending(struct mm_struct *mm)
> }
> #else
> static void set_tlb_ubc_flush_pending(struct mm_struct *mm, pte_t pteval,
> - unsigned long uaddr)
> + unsigned long start,
> + unsigned long end)
> {
> }
>
> @@ -1792,7 +1794,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma,
> */
> pteval = ptep_get_and_clear(mm, address, pvmw.pte);
>
> - set_tlb_ubc_flush_pending(mm, pteval, address);
> + set_tlb_ubc_flush_pending(mm, pteval, address, address + PAGE_SIZE);
> } else {
> pteval = ptep_clear_flush(vma, address, pvmw.pte);
> }
> @@ -2164,7 +2166,7 @@ static bool try_to_migrate_one(struct folio *folio, struct vm_area_struct *vma,
> */
> pteval = ptep_get_and_clear(mm, address, pvmw.pte);
>
> - set_tlb_ubc_flush_pending(mm, pteval, address);
> + set_tlb_ubc_flush_pending(mm, pteval, address, address + PAGE_SIZE);
> } else {
> pteval = ptep_clear_flush(vma, address, pvmw.pte);
> }