DSS2: Small VRFB context allocation bug fixed

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

diff --git a/mm/rmap.c b/mm/rmap.c
index 0597747..0383acf 100644 (file)
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -224,10 +224,14 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
 /*
  * Check that @page is mapped at @address into @mm.
  *
+ * If @sync is false, page_check_address may perform a racy check to avoid
+ * the page table lock when the pte is not present (helpful when reclaiming
+ * highly shared pages).
+ *
  * On success returns with pte mapped and locked.
  */
 pte_t *page_check_address(struct page *page, struct mm_struct *mm,
-                         unsigned long address, spinlock_t **ptlp)
+                         unsigned long address, spinlock_t **ptlp, int sync)
 {
        pgd_t *pgd;
        pud_t *pud;
@@ -249,7 +253,7 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm,
 
        pte = pte_offset_map(pmd, address);
        /* Make a quick check before getting the lock */
-       if (!pte_present(*pte)) {
+       if (!sync && !pte_present(*pte)) {
                pte_unmap(pte);
                return NULL;
        }
@@ -281,7 +285,7 @@ static int page_referenced_one(struct page *page,
        if (address == -EFAULT)
                goto out;
 
-       pte = page_check_address(page, mm, address, &ptl);
+       pte = page_check_address(page, mm, address, &ptl, 0);
        if (!pte)
                goto out;
 
@@ -450,7 +454,7 @@ static int page_mkclean_one(struct page *page, struct vm_area_struct *vma)
        if (address == -EFAULT)
                goto out;
 
-       pte = page_check_address(page, mm, address, &ptl);
+       pte = page_check_address(page, mm, address, &ptl, 1);
        if (!pte)
                goto out;
 
@@ -704,7 +708,7 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
        if (address == -EFAULT)
                goto out;
 
-       pte = page_check_address(page, mm, address, &ptl);
+       pte = page_check_address(page, mm, address, &ptl, 0);
        if (!pte)
                goto out;