[3.8.y.z extended stable] Patch "sched: numa: skip inaccessible VMAs" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    sched: numa: skip inaccessible VMAs

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.16.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 955cdb0e6d509d5308097b071d3ece580acd72d0 Mon Sep 17 00:00:00 2001
From: Mel Gorman <mgorman at suse.de>
Date: Wed, 18 Dec 2013 17:08:40 -0800
Subject: sched: numa: skip inaccessible VMAs

commit 3c67f474558748b604e247d92b55dfe89654c81d upstream.

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

Signed-off-by: Mel Gorman <mgorman at suse.de>
Reviewed-by: Rik van Riel <riel at redhat.com>
Cc: Alex Thorlton <athorlton at sgi.com>
Signed-off-by: Andrew Morton <akpm at linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Signed-off-by: Kamal Mostafa <kamal at 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