[PATCH 3.8 090/166] sched: numa: skip inaccessible VMAs

Kamal Mostafa
2014-01-15T21:51:44Z

From: Mel Gorman <mgorman@suse.de>

commit 3c67f474558748b604e247d92b55dfe89654c81d upstream.

Inaccessible VMA should not be trapping NUMA hint faults. Skip them.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Alex Thorlton <athorlton@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
kernel/sched/fair.c | 7 +++++++
1 file changed, 7 insertions(+)

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 6c8930e..843ab0b 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -935,6 +935,13 @@ void task_numa_work(struct callback_head *work)
if (vma->vm_end - vma->vm_start < HPAGE_SIZE)
continue;

+ /*
+ * Skip inaccessible VMAs to avoid any confusion between
+ * PROT_NONE and NUMA hinting ptes
+ */
+ if (!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)))
+ continue;
+
do {
start = max(start, vma->vm_start);
end = ALIGN(start + (pages << PAGE_SHIFT), HPAGE_SIZE);
--
1.8.3.2