[RFC PATCH v4 6/6] mm: Set VM_LEVEL flags in some tlb_flush functions

From: Zhenyu Ye
Date: Tue Mar 24 2020 - 09:46:34 EST


Set VM_LEVEL flags in some tlb_flush functions.
The relevant functions are:

tlb_flush in asm/tlb.h
get_clear_flush and clear_flush in mm/hugetlbpage.c
flush_pmd|pud_tlb_range in asm-generic/patable.h
do_huge_pmd_numa_page and move_huge_pmd in mm/huge_memory.c

Signed-off-by: Zhenyu Ye <yezhenyu2@xxxxxxxxxx>
---
arch/arm64/include/asm/tlb.h | 12 ++++++++++++
arch/arm64/mm/hugetlbpage.c | 4 ++--
include/asm-generic/pgtable.h | 16 ++++++++++++++--
mm/huge_memory.c | 8 +++++++-
4 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/tlb.h b/arch/arm64/include/asm/tlb.h
index b76df828e6b7..77fe942b30b6 100644
--- a/arch/arm64/include/asm/tlb.h
+++ b/arch/arm64/include/asm/tlb.h
@@ -27,6 +27,18 @@ static inline void tlb_flush(struct mmu_gather *tlb)
bool last_level = !tlb->freed_tables;
unsigned long stride = tlb_get_unmap_size(tlb);

+ /*
+ * mm_gather tracked which levels of the page tables
+ * have been cleared, we can use this info to set
+ * vm->vm_flags.
+ */
+ if (tlb->cleared_ptes)
+ vma.vm_flags |= VM_LEVEL_PTE;
+ else if (tlb->cleared_pmds)
+ vma.vm_flags |= VM_LEVEL_PMD;
+ else if (tlb->cleared_puds)
+ vma.vm_flags |= VM_LEVEL_PUD;
+
/*
* If we're tearing down the address space then we only care about
* invalidating the walk-cache, since the ASID allocator won't
diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index bbeb6a5a6ba6..c35a1bd06bd0 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -140,7 +140,7 @@ static pte_t get_clear_flush(struct mm_struct *mm,
}

if (valid) {
- struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, VM_LEVEL_PTE);
flush_tlb_range(&vma, saddr, addr);
}
return orig_pte;
@@ -161,7 +161,7 @@ static void clear_flush(struct mm_struct *mm,
unsigned long pgsize,
unsigned long ncontig)
{
- struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
+ struct vm_area_struct vma = TLB_FLUSH_VMA(mm, VM_LEVEL_PTE);
unsigned long i, saddr = addr;

for (i = 0; i < ncontig; i++, addr += pgsize, ptep++)
diff --git a/include/asm-generic/pgtable.h b/include/asm-generic/pgtable.h
index e2e2bef07dd2..391e704faf7a 100644
--- a/include/asm-generic/pgtable.h
+++ b/include/asm-generic/pgtable.h
@@ -1160,8 +1160,20 @@ static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr)
* invalidate the entire TLB which is not desitable.
* e.g. see arch/arc: flush_pmd_tlb_range
*/
-#define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
-#define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end)
+#define flush_pmd_tlb_range(vma, addr, end) \
+ do { \
+ vma->vm_flags &= ~(VM_LEVEL_PUD | VM_LEVEL_PTE); \
+ vma->vm_flags |= VM_LEVEL_PMD; \
+ flush_tlb_range(vma, addr, end); \
+ } while (0)
+
+#define flush_pud_tlb_range(vma, addr, end) \
+ do { \
+ vma->vm_flags &= ~(VM_LEVEL_PMD | VM_LEVEL_PTE); \
+ vma->vm_flags |= VM_LEVEL_PUD; \
+ flush_tlb_range(vma, addr, end); \
+ } while (0)
+
#else
#define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG()
#define flush_pud_tlb_range(vma, addr, end) BUILD_BUG()
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 24ad53b4dfc0..9a78b8d865f0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1646,6 +1646,8 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf, pmd_t pmd)
* mapping or not. Hence use the tlb range variant
*/
if (mm_tlb_flush_pending(vma->vm_mm)) {
+ vma->vm_flags &= ~(VM_LEVEL_PUD | VM_LEVEL_PTE);
+ vma->vm_flags |= VM_LEVEL_PMD;
flush_tlb_range(vma, haddr, haddr + HPAGE_PMD_SIZE);
/*
* change_huge_pmd() released the pmd lock before
@@ -1917,8 +1919,12 @@ bool move_huge_pmd(struct vm_area_struct *vma, unsigned long old_addr,
}
pmd = move_soft_dirty_pmd(pmd);
set_pmd_at(mm, new_addr, new_pmd, pmd);
- if (force_flush)
+ if (force_flush) {
+ vma->vm_flags &= ~(VM_LEVEL_PUD | VM_LEVEL_PTE);
+ vma->vm_flags |= VM_LEVEL_PMD;
flush_tlb_range(vma, old_addr, old_addr + PMD_SIZE);
+ }
+
if (new_ptl != old_ptl)
spin_unlock(new_ptl);
spin_unlock(old_ptl);
--
2.19.1