linux-kernel - [PATCH 3/4] mm: mempolicy: Skip inaccessible VMAs when setting MPOL_MF

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Date:	Thu,  2 Oct 2014 14:29:17 +0100
From:	Mel Gorman <mgorman@...e.de>
To:	Dave Jones <davej@...hat.com>
Cc:	Linus Torvalds <torvalds@...ux-foundation.org>,
	Hugh Dickins <hughd@...gle.com>,
	Al Viro <viro@...iv.linux.org.uk>,
	Rik van Riel <riel@...hat.com>,
	Ingo Molnar <mingo@...hat.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Aneesh Kumar <aneesh.kumar@...ux.vnet.ibm.com>,
	Michel Lespinasse <walken@...gle.com>,
	Kirill A Shutemov <kirill.shutemov@...ux.intel.com>,
	Mel Gorman <mgorman@...e.de>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH 3/4] mm: mempolicy: Skip inaccessible VMAs when setting MPOL_MF_LAZY

PROT_NUMA VMAs are skipped to avoid problems distinguishing between
present, prot_none and special entries. MPOL_MF_LAZY is not visible from
userspace since commit a720094ded8c ("mm: mempolicy: Hide MPOL_NOOP and
MPOL_MF_LAZY from userspace for now") but it should still skip VMAs the
same way task_numa_work does.

Signed-off-by: Mel Gorman <mgorman@...e.de>
---
 mm/mempolicy.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 8f5330d..a5877ce 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -683,7 +683,9 @@ queue_pages_range(struct mm_struct *mm, unsigned long start, unsigned long end,
 		}
 
 		if (flags & MPOL_MF_LAZY) {
-			change_prot_numa(vma, start, endvma);
+			/* Similar to task_numa_work, skip inaccessible VMAs */
+			if (vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE))
+				change_prot_numa(vma, start, endvma);
 			goto next;
 		}
 
-- 
1.8.4.5

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