[PATCH] mm/hugetlb: optimize the surplus state transfer code in move_hugetlb_state()

[Miaohe Lin]

We should not transfer the per-node surplus state when we do not cross the
node in order to save some cpu cycles

Signed-off-by: Miaohe Lin <linmia...@huawei.com>
---
 mm/hugetlb.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index da347047ea10..4f2c92ddbca4 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -5632,6 +5632,12 @@ void move_hugetlb_state(struct page *oldpage, struct 
page *newpage, int reason)
                SetHPageTemporary(oldpage);
                ClearHPageTemporary(newpage);
 
+               /*
+                * There is no need to transfer the per-node surplus state
+                * when we do not cross the node.
+                */
+               if (new_nid == old_nid)
+                       return;
                spin_lock(&hugetlb_lock);
                if (h->surplus_huge_pages_node[old_nid]) {
                        h->surplus_huge_pages_node[old_nid]--;
-- 
2.19.1