mm/mempolicy.c: skip VM_HUGETLB and VM_MIXEDMAP VMA for lazy mbind

VM_HUGETLB and VM_MIXEDMAP vma needs to be excluded to avoid compound
pages being marked for migration and unexpected COWs when handling
hugetlb fault.

Thanks to Naoya Horiguchi for reminding me on these checks.

Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Signed-off-by: Gavin Guo <gavin.guo@canonical.com>
Suggested-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: David Rientjes <rientjes@google.com>
Cc: SeongJae Park <sj38.park@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9a3f6b9..8cbc743 100644 (file)
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -643,7 +643,9 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
 
        if (flags & MPOL_MF_LAZY) {
                /* Similar to task_numa_work, skip inaccessible VMAs */
-               if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
+               if (!is_vm_hugetlb_page(vma) &&
+                       (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)) &&
+                       !(vma->vm_flags & VM_MIXEDMAP))
                        change_prot_numa(vma, start, endvma);
                return 1;
        }