[PATCH 3.8 091/166] mm: numa: clear numa hinting information on mprotect

[Kamal Mostafa]

3.8.13.16 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Mel Gorman <mgorman@xxxxxxx>

commit 1667918b6483b12a6496bf54151b827b8235d7b1 upstream.

On a protection change it is no longer clear if the page should be still
accessible.  This patch clears the NUMA hinting fault bits on a
protection change.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Alex Thorlton <athorlton@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx>
---
 mm/huge_memory.c | 2 ++
 mm/mprotect.c    | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 594b3c1..a67726d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1504,6 +1504,8 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd,
 		ret = 1;
 		if (!prot_numa) {
 			entry = pmdp_get_and_clear(mm, addr, pmd);
+			if (pmd_numa(entry))
+				entry = pmd_mknonnuma(entry);
 			entry = pmd_modify(entry, newprot);
 			ret = HPAGE_PMD_NR;
 			BUG_ON(pmd_write(entry));
diff --git a/mm/mprotect.c b/mm/mprotect.c
index 79abf13..c477655 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -56,6 +56,8 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd,
 
 			if (!prot_numa) {
 				ptent = ptep_modify_prot_start(mm, addr, pte);
+				if (pte_numa(ptent))
+					ptent = pte_mknonnuma(ptent);
 				ptent = pte_modify(ptent, newprot);
 				updated = true;
 			} else {
-- 
1.8.3.2

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