[tip:core/urgent] mm: numa: Do not account for a hinting fault if we raced

[tip-bot for Mel Gorman]

Commit-ID:  1dd49bfa3465756b3ce72214b58a33e4afb67aa3
Gitweb:     http://git.kernel.org/tip/1dd49bfa3465756b3ce72214b58a33e4afb67aa3
Author:     Mel Gorman <mgorman@xxxxxxx>
AuthorDate: Mon, 7 Oct 2013 11:28:42 +0100
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Tue, 29 Oct 2013 11:37:05 +0100

mm: numa: Do not account for a hinting fault if we raced

If another task handled a hinting fault in parallel then do not double
account for it.

Signed-off-by: Mel Gorman <mgorman@xxxxxxx>
Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Cc: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Link: http://lkml.kernel.org/r/1381141781-10992-5-git-send-email-mgorman@xxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 mm/huge_memory.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 610e3df..33ee637 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1325,8 +1325,11 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 
 check_same:
 	spin_lock(&mm->page_table_lock);
-	if (unlikely(!pmd_same(pmd, *pmdp)))
+	if (unlikely(!pmd_same(pmd, *pmdp))) {
+		/* Someone else took our fault */
+		current_nid = -1;
 		goto out_unlock;
+	}
 clear_pmdnuma:
 	pmd = pmd_mknonnuma(pmd);
 	set_pmd_at(mm, haddr, pmdp, pmd);
--
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