[PATCH 5/7] Add freed_tables argument to flush_tlb_mm_range

[Rik van Riel]

Add an argument to flush_tlb_mm_range to indicate whether page tables
are about to be freed after this TLB flush. This allows for an
optimization of flush_tlb_mm_range to skip CPUs in lazy TLB mode.

No functional changes.

Signed-off-by: Rik van Riel <r...@surriel.com>
---
 arch/x86/include/asm/tlb.h      |  2 +-
 arch/x86/include/asm/tlbflush.h | 10 ++++++----
 arch/x86/kernel/ldt.c           |  2 +-
 arch/x86/kernel/vm86_32.c       |  2 +-
 arch/x86/mm/tlb.c               |  3 ++-
 5 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/arch/x86/include/asm/tlb.h b/arch/x86/include/asm/tlb.h
index afbe7d1e68cf..404b8b1d44f5 100644
--- a/arch/x86/include/asm/tlb.h
+++ b/arch/x86/include/asm/tlb.h
@@ -20,7 +20,7 @@ static inline void tlb_flush(struct mmu_gather *tlb)
                end = tlb->end;
        }
 
-       flush_tlb_mm_range(tlb->mm, start, end, stride_shift);
+       flush_tlb_mm_range(tlb->mm, start, end, stride_shift, 
tlb->freed_tables);
 }
 
 /*
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d6c0cd9e9591..1dea9860ce5b 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -536,22 +536,24 @@ struct flush_tlb_info {
 
 #define local_flush_tlb() __flush_tlb()
 
-#define flush_tlb_mm(mm)       flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL)
+#define flush_tlb_mm(mm)                                               \
+               flush_tlb_mm_range(mm, 0UL, TLB_FLUSH_ALL, 0UL, true)
 
 #define flush_tlb_range(vma, start, end)                               \
        flush_tlb_mm_range((vma)->vm_mm, start, end,                    \
                           ((vma)->vm_flags & VM_HUGETLB)               \
                                ? huge_page_shift(hstate_vma(vma))      \
-                               : PAGE_SHIFT)
+                               : PAGE_SHIFT, false)
 
 extern void flush_tlb_all(void);
 extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-                               unsigned long end, unsigned int stride_shift);
+                               unsigned long end, unsigned int stride_shift,
+                               bool freed_tables);
 extern void flush_tlb_kernel_range(unsigned long start, unsigned long end);
 
 static inline void flush_tlb_page(struct vm_area_struct *vma, unsigned long a)
 {
-       flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT);
+       flush_tlb_mm_range(vma->vm_mm, a, a + PAGE_SIZE, PAGE_SHIFT, false);
 }
 
 void native_flush_tlb_others(const struct cpumask *cpumask,
diff --git a/arch/x86/kernel/ldt.c b/arch/x86/kernel/ldt.c
index 733e6ace0fa4..91eae79ef686 100644
--- a/arch/x86/kernel/ldt.c
+++ b/arch/x86/kernel/ldt.c
@@ -273,7 +273,7 @@ map_ldt_struct(struct mm_struct *mm, struct ldt_struct 
*ldt, int slot)
        map_ldt_struct_to_user(mm);
 
        va = (unsigned long)ldt_slot_va(slot);
-       flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, 0);
+       flush_tlb_mm_range(mm, va, va + LDT_SLOT_STRIDE, 0, false);
 
        ldt->slot = slot;
        return 0;
diff --git a/arch/x86/kernel/vm86_32.c b/arch/x86/kernel/vm86_32.c
index 1c03e4aa6474..91460acbb650 100644
--- a/arch/x86/kernel/vm86_32.c
+++ b/arch/x86/kernel/vm86_32.c
@@ -199,7 +199,7 @@ static void mark_screen_rdonly(struct mm_struct *mm)
        pte_unmap_unlock(pte, ptl);
 out:
        up_write(&mm->mmap_sem);
-       flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, 0UL);
+       flush_tlb_mm_range(mm, 0xA0000, 0xA0000 + 32*PAGE_SIZE, 0UL, false);
 }
 
 
diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 1224f7fb1311..1d74fbc71ad6 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -611,7 +611,8 @@ void native_flush_tlb_others(const struct cpumask *cpumask,
 static unsigned long tlb_single_page_flush_ceiling __read_mostly = 33;
 
 void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
-                               unsigned long end, unsigned int stride_shift)
+                               unsigned long end, unsigned int stride_shift,
+                               bool freed_tables)
 {
        int cpu;
 
-- 
2.17.1