mincore: do nested page table walks

Do page table walks with the well-known nested loops we use in several
other places already.

This avoids doing full page table walks after every pte range and also
allows to handle unmapped areas bigger than one pte range in one go.

Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/mincore.c b/mm/mincore.c
index 211604adc23ccfb52ef4313534f5ad0fde2173db..9ac42dc6d7b61481b1eedb8e12b463bd151b1f92 100644 (file)
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -144,6 +144,60 @@ static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
        pte_unmap_unlock(ptep - 1, ptl);
 }
 
+static void mincore_pmd_range(struct vm_area_struct *vma, pud_t *pud,
+                       unsigned long addr, unsigned long end,
+                       unsigned char *vec)
+{
+       unsigned long next;
+       pmd_t *pmd;
+
+       pmd = pmd_offset(pud, addr);
+       do {
+               next = pmd_addr_end(addr, end);
+               if (pmd_none_or_clear_bad(pmd))
+                       mincore_unmapped_range(vma, addr, next, vec);
+               else
+                       mincore_pte_range(vma, pmd, addr, next, vec);
+               vec += (next - addr) >> PAGE_SHIFT;
+       } while (pmd++, addr = next, addr != end);
+}
+
+static void mincore_pud_range(struct vm_area_struct *vma, pgd_t *pgd,
+                       unsigned long addr, unsigned long end,
+                       unsigned char *vec)
+{
+       unsigned long next;
+       pud_t *pud;
+
+       pud = pud_offset(pgd, addr);
+       do {
+               next = pud_addr_end(addr, end);
+               if (pud_none_or_clear_bad(pud))
+                       mincore_unmapped_range(vma, addr, next, vec);
+               else
+                       mincore_pmd_range(vma, pud, addr, next, vec);
+               vec += (next - addr) >> PAGE_SHIFT;
+       } while (pud++, addr = next, addr != end);
+}
+
+static void mincore_page_range(struct vm_area_struct *vma,
+                       unsigned long addr, unsigned long end,
+                       unsigned char *vec)
+{
+       unsigned long next;
+       pgd_t *pgd;
+
+       pgd = pgd_offset(vma->vm_mm, addr);
+       do {
+               next = pgd_addr_end(addr, end);
+               if (pgd_none_or_clear_bad(pgd))
+                       mincore_unmapped_range(vma, addr, next, vec);
+               else
+                       mincore_pud_range(vma, pgd, addr, next, vec);
+               vec += (next - addr) >> PAGE_SHIFT;
+       } while (pgd++, addr = next, addr != end);
+}
+
 /*
  * Do a chunk of "sys_mincore()". We've already checked
  * all the arguments, we hold the mmap semaphore: we should
@@ -151,9 +205,6 @@ static void mincore_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
  */
 static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *vec)
 {
-       pgd_t *pgd;
-       pud_t *pud;
-       pmd_t *pmd;
        struct vm_area_struct *vma;
        unsigned long end;
 
@@ -170,21 +221,11 @@ static long do_mincore(unsigned long addr, unsigned long pages, unsigned char *v
 
        end = pmd_addr_end(addr, end);
 
-       pgd = pgd_offset(vma->vm_mm, addr);
-       if (pgd_none_or_clear_bad(pgd))
-               goto none_mapped;
-       pud = pud_offset(pgd, addr);
-       if (pud_none_or_clear_bad(pud))
-               goto none_mapped;
-       pmd = pmd_offset(pud, addr);
-       if (pmd_none_or_clear_bad(pmd))
-               goto none_mapped;
-
-       mincore_pte_range(vma, pmd, addr, end, vec);
-       return (end - addr) >> PAGE_SHIFT;
+       if (is_vm_hugetlb_page(vma))
+               mincore_hugetlb_page_range(vma, addr, end, vec);
+       else
+               mincore_page_range(vma, addr, end, vec);
 
-none_mapped:
-       mincore_unmapped_range(vma, addr, end, vec);
        return (end - addr) >> PAGE_SHIFT;
 }