Merge branch 'master'

[pandora-kernel.git] / mm / memory.c

diff --git a/mm/memory.c b/mm/memory.c
index e9ef599..0f60baf 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -372,7 +372,9 @@ copy_one_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
                        /* make sure dst_mm is on swapoff's mmlist. */
                        if (unlikely(list_empty(&dst_mm->mmlist))) {
                                spin_lock(&mmlist_lock);
-                               list_add(&dst_mm->mmlist, &src_mm->mmlist);
+                               if (list_empty(&dst_mm->mmlist))
+                                       list_add(&dst_mm->mmlist,
+                                                &src_mm->mmlist);
                                spin_unlock(&mmlist_lock);
                        }
                }
@@ -1978,9 +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)
@@ -2007,9 +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;