From 4355c018c2ba8017592520573e76ad376ad656db Mon Sep 17 00:00:00 2001
From: Liang Chen <liangchen.linux@gmail.com>
Date: Tue, 15 Mar 2016 14:56:42 -0700
Subject: [PATCH] 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>
---
 mm/mempolicy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9a3f6b90e628..8cbc74387df3 100644
--- 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;
 	}
-- 
2.20.1