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 9a3f6b90e6283b24bff091213768612b04b6d928..8cbc74387df38c5572001bd2e06bd8da1af5ab70 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;
        }