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-rw-r--r--mm/memory.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/mm/memory.c b/mm/memory.c
index d68421dd64e..0f60baf6f69 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1980,9 +1980,10 @@ static inline int handle_pte_fault(struct mm_struct *mm,
pte_t *pte, pmd_t *pmd, int write_access)
{
pte_t entry;
+ pte_t old_entry;
spinlock_t *ptl;
- entry = *pte;
+ old_entry = entry = *pte;
if (!pte_present(entry)) {
if (pte_none(entry)) {
if (!vma->vm_ops || !vma->vm_ops->nopage)
@@ -2009,9 +2010,20 @@ static inline int handle_pte_fault(struct mm_struct *mm,
entry = pte_mkdirty(entry);
}
entry = pte_mkyoung(entry);
- ptep_set_access_flags(vma, address, pte, entry, write_access);
- update_mmu_cache(vma, address, entry);
- lazy_mmu_prot_update(entry);
+ if (!pte_same(old_entry, entry)) {
+ ptep_set_access_flags(vma, address, pte, entry, write_access);
+ update_mmu_cache(vma, address, entry);
+ lazy_mmu_prot_update(entry);
+ } else {
+ /*
+ * This is needed only for protection faults but the arch code
+ * is not yet telling us if this is a protection fault or not.
+ * This still avoids useless tlb flushes for .text page faults
+ * with threads.
+ */
+ if (write_access)
+ flush_tlb_page(vma, address);
+ }
unlock:
pte_unmap_unlock(pte, ptl);
return VM_FAULT_MINOR;