[PATCH v3 2/4] riscv: Improve flush_tlb_range() for hugetlb pages

From: Alexandre Ghiti
Date: Tue Aug 01 2023 - 04:56:51 EST


flush_tlb_range() uses a fixed stride of PAGE_SIZE and in its current form,
when a hugetlb mapping needs to be flushed, flush_tlb_range() flushes the
whole tlb: so set a stride of the size of the hugetlb mapping in order to
only flush the hugetlb mapping.

Note that THPs are directly handled by flush_pmd_tlb_range().

Signed-off-by: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Reviewed-by: Andrew Jones <ajones@xxxxxxxxxxxxxxxx>
---
arch/riscv/mm/tlbflush.c | 9 ++++++++-
1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index fa03289853d8..d883df0dee4a 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -3,6 +3,7 @@
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/sched.h>
+#include <linux/hugetlb.h>
#include <asm/sbi.h>
#include <asm/mmu_context.h>

@@ -147,7 +148,13 @@ 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)
{
- __flush_tlb_range(vma->vm_mm, start, end - start, PAGE_SIZE);
+ unsigned long stride_size;
+
+ stride_size = is_vm_hugetlb_page(vma) ?
+ huge_page_size(hstate_vma(vma)) :
+ PAGE_SIZE;
+
+ __flush_tlb_range(vma->vm_mm, start, end - start, stride_size);
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void flush_pmd_tlb_range(struct vm_area_struct *vma, unsigned long start,
--
2.39.2