1 files changed, 20 insertions, 9 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ac843d32b019..ede7e7f5d1ab 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1510,16 +1510,29 @@ static int free_pool_huge_page(struct hstate *h, nodemask_t *nodes_allowed,
 
 /*
  * Dissolve a given free hugepage into free buddy pages. This function does
- * nothing for in-use (including surplus) hugepages. Returns -EBUSY if the
- * dissolution fails because a give page is not a free hugepage, or because
- * free hugepages are fully reserved.
+ * nothing for in-use hugepages and non-hugepages.
+ * This function returns values like below:
+ *
+ *  -EBUSY: failed to dissolved free hugepages or the hugepage is in-use
+ *          (allocated or reserved.)
+ *       0: successfully dissolved free hugepages or the page is not a
+ *          hugepage (considered as already dissolved)
  */
 int dissolve_free_huge_page(struct page *page)
 {
         int rc = -EBUSY;
 
+        /* Not to disrupt normal path by vainly holding hugetlb_lock */
+        if (!PageHuge(page))
+                return 0;
+
         spin_lock(&hugetlb_lock);
-        if (PageHuge(page) && !page_count(page)) {
+        if (!PageHuge(page)) {
+                rc = 0;
+                goto out;
+        }
+
+        if (!page_count(page)) {
                 struct page *head = compound_head(page);
                 struct hstate *h = page_hstate(head);
                 int nid = page_to_nid(head);
@@ -1564,11 +1577,9 @@ int dissolve_free_huge_pages(unsigned long start_pfn, unsigned long end_pfn)
 
         for (pfn = start_pfn; pfn < end_pfn; pfn += 1 << minimum_order) {
                 page = pfn_to_page(pfn);
-                if (PageHuge(page) && !page_count(page)) {
-                        rc = dissolve_free_huge_page(page);
-                        if (rc)
-                                break;
-                }
+                rc = dissolve_free_huge_page(page);
+                if (rc)
+                        break;
         }
 
         return rc;