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-rw-r--r--mm/rmap.c54
1 files changed, 35 insertions, 19 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index f21f4a1d6a1c..941bf82e8961 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -497,41 +497,51 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
struct mm_struct *mm = vma->vm_mm;
int referenced = 0;
- /*
- * Don't want to elevate referenced for mlocked page that gets this far,
- * in order that it progresses to try_to_unmap and is moved to the
- * unevictable list.
- */
- if (vma->vm_flags & VM_LOCKED) {
- *mapcount = 0; /* break early from loop */
- *vm_flags |= VM_LOCKED;
- goto out;
- }
-
- /* Pretend the page is referenced if the task has the
- swap token and is in the middle of a page fault. */
- if (mm != current->mm && has_swap_token(mm) &&
- rwsem_is_locked(&mm->mmap_sem))
- referenced++;
-
if (unlikely(PageTransHuge(page))) {
pmd_t *pmd;
spin_lock(&mm->page_table_lock);
+ /*
+ * rmap might return false positives; we must filter
+ * these out using page_check_address_pmd().
+ */
pmd = page_check_address_pmd(page, mm, address,
PAGE_CHECK_ADDRESS_PMD_FLAG);
- if (pmd && !pmd_trans_splitting(*pmd) &&
- pmdp_clear_flush_young_notify(vma, address, pmd))
+ if (!pmd) {
+ spin_unlock(&mm->page_table_lock);
+ goto out;
+ }
+
+ if (vma->vm_flags & VM_LOCKED) {
+ spin_unlock(&mm->page_table_lock);
+ *mapcount = 0; /* break early from loop */
+ *vm_flags |= VM_LOCKED;
+ goto out;
+ }
+
+ /* go ahead even if the pmd is pmd_trans_splitting() */
+ if (pmdp_clear_flush_young_notify(vma, address, pmd))
referenced++;
spin_unlock(&mm->page_table_lock);
} else {
pte_t *pte;
spinlock_t *ptl;
+ /*
+ * rmap might return false positives; we must filter
+ * these out using page_check_address().
+ */
pte = page_check_address(page, mm, address, &ptl, 0);
if (!pte)
goto out;
+ if (vma->vm_flags & VM_LOCKED) {
+ pte_unmap_unlock(pte, ptl);
+ *mapcount = 0; /* break early from loop */
+ *vm_flags |= VM_LOCKED;
+ goto out;
+ }
+
if (ptep_clear_flush_young_notify(vma, address, pte)) {
/*
* Don't treat a reference through a sequentially read
@@ -546,6 +556,12 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
pte_unmap_unlock(pte, ptl);
}
+ /* Pretend the page is referenced if the task has the
+ swap token and is in the middle of a page fault. */
+ if (mm != current->mm && has_swap_token(mm) &&
+ rwsem_is_locked(&mm->mmap_sem))
+ referenced++;
+
(*mapcount)--;
if (referenced)
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