[PATCH] RISC-V: add uniprocessor flush_tlb_range() support
Jisheng Zhang
jszhang at kernel.org
Sun Jan 28 23:49:30 PST 2024
On Thu, Jan 25, 2024 at 02:20:44PM +0800, Yunhui Cui wrote:
> Add support for flush_tlb_range() to improve TLB performance for
> UP systems. In order to avoid the mutual inclusion of tlbflush.h
> and hugetlb.h, the UP part is also implemented in tlbflush.c.
Hi Yunhui,
IIRC, Samuel sent similar patch series a few weeks ago.
https://lore.kernel.org/linux-riscv/20240102220134.3229156-1-samuel.holland@sifive.com/
After that series, do you still need this patch?
Thanks
>
> Signed-off-by: Yunhui Cui <cuiyunhui at bytedance.com>
> ---
> arch/riscv/include/asm/tlbflush.h | 61 ++++++----
> arch/riscv/mm/Makefile | 2 +-
> arch/riscv/mm/tlbflush.c | 195 ++++++++++++++++++------------
> 3 files changed, 156 insertions(+), 102 deletions(-)
>
> diff --git a/arch/riscv/include/asm/tlbflush.h b/arch/riscv/include/asm/tlbflush.h
> index 928f096dca21..426f043fb450 100644
> --- a/arch/riscv/include/asm/tlbflush.h
> +++ b/arch/riscv/include/asm/tlbflush.h
> @@ -10,12 +10,21 @@
> #include <linux/mm_types.h>
> #include <asm/smp.h>
> #include <asm/errata_list.h>
> +#include <asm/tlbbatch.h>
>
> #define FLUSH_TLB_MAX_SIZE ((unsigned long)-1)
> #define FLUSH_TLB_NO_ASID ((unsigned long)-1)
>
> #ifdef CONFIG_MMU
> extern unsigned long asid_mask;
> +DECLARE_STATIC_KEY_FALSE(use_asid_allocator);
> +
> +struct flush_tlb_range_data {
> + unsigned long asid;
> + unsigned long start;
> + unsigned long size;
> + unsigned long stride;
> +};
>
> static inline void local_flush_tlb_all(void)
> {
> @@ -27,12 +36,40 @@ static inline void local_flush_tlb_page(unsigned long addr)
> {
> ALT_FLUSH_TLB_PAGE(__asm__ __volatile__ ("sfence.vma %0" : : "r" (addr) : "memory"));
> }
> +
> +static inline void local_flush_tlb_all_asid(unsigned long asid)
> +{
> + if (asid != FLUSH_TLB_NO_ASID)
> + __asm__ __volatile__ ("sfence.vma x0, %0"
> + :
> + : "r" (asid)
> + : "memory");
> + else
> + local_flush_tlb_all();
> +}
> +
> +static inline void local_flush_tlb_page_asid(unsigned long addr,
> + unsigned long asid)
> +{
> + if (asid != FLUSH_TLB_NO_ASID)
> + __asm__ __volatile__ ("sfence.vma %0, %1"
> + :
> + : "r" (addr), "r" (asid)
> + : "memory");
> + else
> + local_flush_tlb_page(addr);
> +}
> +
> +static inline unsigned long get_mm_asid(struct mm_struct *mm)
> +{
> + return static_branch_unlikely(&use_asid_allocator) ?
> + atomic_long_read(&mm->context.id) & asid_mask : FLUSH_TLB_NO_ASID;
> +}
> #else /* CONFIG_MMU */
> #define local_flush_tlb_all() do { } while (0)
> #define local_flush_tlb_page(addr) do { } while (0)
> #endif /* CONFIG_MMU */
>
> -#if defined(CONFIG_SMP) && defined(CONFIG_MMU)
> void flush_tlb_all(void);
> void flush_tlb_mm(struct mm_struct *mm);
> void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
> @@ -55,26 +92,4 @@ void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
> void arch_flush_tlb_batched_pending(struct mm_struct *mm);
> void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);
>
> -#else /* CONFIG_SMP && CONFIG_MMU */
> -
> -#define flush_tlb_all() local_flush_tlb_all()
> -#define flush_tlb_page(vma, addr) local_flush_tlb_page(addr)
> -
> -static inline void flush_tlb_range(struct vm_area_struct *vma,
> - unsigned long start, unsigned long end)
> -{
> - local_flush_tlb_all();
> -}
> -
> -/* Flush a range of kernel pages */
> -static inline void flush_tlb_kernel_range(unsigned long start,
> - unsigned long end)
> -{
> - 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/Makefile b/arch/riscv/mm/Makefile
> index 2c869f8026a8..7c6c4c858a6b 100644
> --- a/arch/riscv/mm/Makefile
> +++ b/arch/riscv/mm/Makefile
> @@ -19,7 +19,7 @@ obj-y += context.o
> obj-y += pmem.o
>
> ifeq ($(CONFIG_MMU),y)
> -obj-$(CONFIG_SMP) += tlbflush.o
> +obj-y += tlbflush.o
> endif
> obj-$(CONFIG_HUGETLB_PAGE) += hugetlbpage.o
> obj-$(CONFIG_PTDUMP_CORE) += ptdump.o
> diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
> index 8d12b26f5ac3..4765603fa08a 100644
> --- a/arch/riscv/mm/tlbflush.c
> +++ b/arch/riscv/mm/tlbflush.c
> @@ -6,28 +6,36 @@
> #include <linux/hugetlb.h>
> #include <asm/sbi.h>
> #include <asm/mmu_context.h>
> +#include <asm/tlbflush.h>
>
> -static inline void local_flush_tlb_all_asid(unsigned long asid)
> +static unsigned long get_stride_size(struct vm_area_struct *vma)
> {
> - if (asid != FLUSH_TLB_NO_ASID)
> - __asm__ __volatile__ ("sfence.vma x0, %0"
> - :
> - : "r" (asid)
> - : "memory");
> - else
> - local_flush_tlb_all();
> -}
> + unsigned long stride_size;
>
> -static inline void local_flush_tlb_page_asid(unsigned long addr,
> - unsigned long asid)
> -{
> - if (asid != FLUSH_TLB_NO_ASID)
> - __asm__ __volatile__ ("sfence.vma %0, %1"
> - :
> - : "r" (addr), "r" (asid)
> - : "memory");
> - else
> - local_flush_tlb_page(addr);
> + if (!is_vm_hugetlb_page(vma))
> + return PAGE_SIZE;
> +
> + stride_size = huge_page_size(hstate_vma(vma));
> +
> + /*
> + * As stated in the privileged specification, every PTE in a
> + * NAPOT region must be invalidated, so reset the stride in that
> + * case.
> + */
> + if (has_svnapot()) {
> + if (stride_size >= PGDIR_SIZE)
> + stride_size = PGDIR_SIZE;
> + else if (stride_size >= P4D_SIZE)
> + stride_size = P4D_SIZE;
> + else if (stride_size >= PUD_SIZE)
> + stride_size = PUD_SIZE;
> + else if (stride_size >= PMD_SIZE)
> + stride_size = PMD_SIZE;
> + else
> + stride_size = PAGE_SIZE;
> + }
> +
> + return stride_size;
> }
>
> /*
> @@ -66,31 +74,12 @@ static inline void local_flush_tlb_range_asid(unsigned long start,
> local_flush_tlb_range_threshold_asid(start, size, stride, asid);
> }
>
> -void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
> -{
> - local_flush_tlb_range_asid(start, end, PAGE_SIZE, FLUSH_TLB_NO_ASID);
> -}
> -
> +#ifdef CONFIG_SMP
> static void __ipi_flush_tlb_all(void *info)
> {
> local_flush_tlb_all();
> }
>
> -void flush_tlb_all(void)
> -{
> - if (riscv_use_ipi_for_rfence())
> - on_each_cpu(__ipi_flush_tlb_all, NULL, 1);
> - else
> - sbi_remote_sfence_vma_asid(NULL, 0, FLUSH_TLB_MAX_SIZE, FLUSH_TLB_NO_ASID);
> -}
> -
> -struct flush_tlb_range_data {
> - unsigned long asid;
> - unsigned long start;
> - unsigned long size;
> - unsigned long stride;
> -};
> -
> static void __ipi_flush_tlb_range_asid(void *info)
> {
> struct flush_tlb_range_data *d = info;
> @@ -138,10 +127,18 @@ static void __flush_tlb_range(struct cpumask *cmask, unsigned long asid,
> put_cpu();
> }
>
> -static inline unsigned long get_mm_asid(struct mm_struct *mm)
> +void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
> {
> - return static_branch_unlikely(&use_asid_allocator) ?
> - atomic_long_read(&mm->context.id) & asid_mask : FLUSH_TLB_NO_ASID;
> + __flush_tlb_range(mm_cpumask(vma->vm_mm), get_mm_asid(vma->vm_mm),
> + addr, PAGE_SIZE, PAGE_SIZE);
> +}
> +
> +void flush_tlb_all(void)
> +{
> + if (riscv_use_ipi_for_rfence())
> + on_each_cpu(__ipi_flush_tlb_all, NULL, 1);
> + else
> + sbi_remote_sfence_vma_asid(NULL, 0, FLUSH_TLB_MAX_SIZE, FLUSH_TLB_NO_ASID);
> }
>
> void flush_tlb_mm(struct mm_struct *mm)
> @@ -158,41 +155,12 @@ void flush_tlb_mm_range(struct mm_struct *mm,
> start, end - start, page_size);
> }
>
> -void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
> -{
> - __flush_tlb_range(mm_cpumask(vma->vm_mm), get_mm_asid(vma->vm_mm),
> - addr, PAGE_SIZE, PAGE_SIZE);
> -}
> -
> void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end)
> {
> unsigned long stride_size;
>
> - if (!is_vm_hugetlb_page(vma)) {
> - stride_size = PAGE_SIZE;
> - } else {
> - stride_size = huge_page_size(hstate_vma(vma));
> -
> - /*
> - * As stated in the privileged specification, every PTE in a
> - * NAPOT region must be invalidated, so reset the stride in that
> - * case.
> - */
> - if (has_svnapot()) {
> - if (stride_size >= PGDIR_SIZE)
> - stride_size = PGDIR_SIZE;
> - else if (stride_size >= P4D_SIZE)
> - stride_size = P4D_SIZE;
> - else if (stride_size >= PUD_SIZE)
> - stride_size = PUD_SIZE;
> - else if (stride_size >= PMD_SIZE)
> - stride_size = PMD_SIZE;
> - else
> - stride_size = PAGE_SIZE;
> - }
> - }
> -
> + stride_size = get_stride_size(vma);
> __flush_tlb_range(mm_cpumask(vma->vm_mm), get_mm_asid(vma->vm_mm),
> start, end - start, stride_size);
> }
> @@ -203,6 +171,12 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
> start, end - start, PAGE_SIZE);
> }
>
> +void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
> +{
> + __flush_tlb_range(&batch->cpumask, FLUSH_TLB_NO_ASID, 0,
> + FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
> +}
> +
> #ifdef CONFIG_TRANSPARENT_HUGEPAGE
> void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> unsigned long end)
> @@ -212,6 +186,77 @@ void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> }
> #endif
>
> +#else
> +static void __flush_tlb_range_up(struct mm_struct *mm, unsigned long start,
> + unsigned long size, unsigned long stride)
> +{
> + unsigned long asid = FLUSH_TLB_NO_ASID;
> +
> + if (mm)
> + asid = get_mm_asid(mm);
> +
> + local_flush_tlb_range_asid(start, size, stride, asid);
> +}
> +
> +void flush_tlb_page(struct vm_area_struct *vma, unsigned long addr)
> +{
> + local_flush_tlb_page(addr);
> +}
> +
> +void flush_tlb_all(void)
> +{
> + local_flush_tlb_all();
> +}
> +
> +void flush_tlb_mm(struct mm_struct *mm)
> +{
> + __flush_tlb_range_up(mm, 0, FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
> +}
> +
> +void flush_tlb_mm_range(struct mm_struct *mm,
> + unsigned long start, unsigned long end,
> + unsigned int page_size)
> +{
> + __flush_tlb_range_up(mm, start, end - start, page_size);
> +}
> +
> +void flush_tlb_range(struct vm_area_struct *vma,
> + unsigned long start, unsigned long end)
> +{
> + unsigned long stride_size;
> +
> + stride_size = get_stride_size(vma);
> + __flush_tlb_range_up(vma->vm_mm, start, end - start, stride_size);
> +}
> +
> +/* Flush a range of kernel pages */
> +void flush_tlb_kernel_range(unsigned long start,
> + unsigned long end)
> +{
> + __flush_tlb_range_up(NULL, start, end - start, PAGE_SIZE);
> +}
> +
> +void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
> +{
> + __flush_tlb_range_up(NULL, 0, FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
> +}
> +
> +#ifdef CONFIG_TRANSPARENT_HUGEPAGE
> +void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
> + unsigned long end)
> +{
> + __flush_tlb_range_up(vma->vm_mm, start, end - start, PMD_SIZE);
> +}
> +#endif
> +
> +#endif
> +
> +void local_flush_tlb_kernel_range(unsigned long start, unsigned long end)
> +{
> + local_flush_tlb_range_asid(start, end - start, PAGE_SIZE,
> + FLUSH_TLB_NO_ASID);
> +}
> +
> bool arch_tlbbatch_should_defer(struct mm_struct *mm)
> {
> return true;
> @@ -228,9 +273,3 @@ void arch_flush_tlb_batched_pending(struct mm_struct *mm)
> {
> flush_tlb_mm(mm);
> }
> -
> -void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
> -{
> - __flush_tlb_range(&batch->cpumask, FLUSH_TLB_NO_ASID, 0,
> - FLUSH_TLB_MAX_SIZE, PAGE_SIZE);
> -}
> --
> 2.20.1
>
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