[PATCH v2 4/4] khugepaged: fix wrong result value for trace_mm_collapse_huge_page_isolate()

[Miaohe Lin]

In writable and !referenced case, the result value should be
SCAN_LACK_REFERENCED_PAGE for trace_mm_collapse_huge_page_isolate()
instead of default 0 (SCAN_FAIL) here.

Fixes: 7d2eba0557c1 ("mm: add tracepoint for scanning pages")
Signed-off-by: Miaohe Lin <linmia...@huawei.com>
Acked-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 mm/khugepaged.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e886a8618c33..adf677246d86 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -716,17 +716,17 @@ static int __collapse_huge_page_isolate(struct 
vm_area_struct *vma,
                if (pte_write(pteval))
                        writable = true;
        }
-       if (likely(writable)) {
-               if (likely(referenced)) {
-                       result = SCAN_SUCCEED;
-                       trace_mm_collapse_huge_page_isolate(page, none_or_zero,
-                                                           referenced, 
writable, result);
-                       return 1;
-               }
-       } else {
+
+       if (unlikely(!writable)) {
                result = SCAN_PAGE_RO;
+       } else if (unlikely(!referenced)) {
+               result = SCAN_LACK_REFERENCED_PAGE;
+       } else {
+               result = SCAN_SUCCEED;
+               trace_mm_collapse_huge_page_isolate(page, none_or_zero,
+                                                   referenced, writable, 
result);
+               return 1;
        }
-
 out:
        release_pte_pages(pte, _pte, compound_pagelist);
        trace_mm_collapse_huge_page_isolate(page, none_or_zero,
-- 
2.19.1