thp: remove wake_up_interruptible in the exit path

Add the check of kthread_should_stop() to the conditions which are used to
wakeup on khugepaged_wait, then kthread_stop is enough to let the thread
exit

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 21 insertions, 14 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 46e3f150a6ca..a94c07a1b3c5 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -154,8 +154,6 @@ static int start_khugepaged(void)
 
                 set_recommended_min_free_kbytes();
         } else if (khugepaged_thread) {
-                /* wakeup to exit */
-                wake_up_interruptible(&khugepaged_wait);
                 kthread_stop(khugepaged_thread);
                 khugepaged_thread = NULL;
         }
@@ -2221,7 +2219,7 @@ static int khugepaged_has_work(void)
 static int khugepaged_wait_event(void)
 {
         return !list_empty(&khugepaged_scan.mm_head) ||
-                !khugepaged_enabled();
+                kthread_should_stop();
 }
 
 static void khugepaged_do_scan(struct page **hpage)
@@ -2288,6 +2286,24 @@ static struct page *khugepaged_alloc_hugepage(void)
 }
 #endif
 
+static void khugepaged_wait_work(void)
+{
+        try_to_freeze();
+
+        if (khugepaged_has_work()) {
+                if (!khugepaged_scan_sleep_millisecs)
+                        return;
+
+                wait_event_freezable_timeout(khugepaged_wait,
+                                             kthread_should_stop(),
+                        msecs_to_jiffies(khugepaged_scan_sleep_millisecs));
+                return;
+        }
+
+        if (khugepaged_enabled())
+                wait_event_freezable(khugepaged_wait, khugepaged_wait_event());
+}
+
 static void khugepaged_loop(void)
 {
         struct page *hpage;
@@ -2312,17 +2328,8 @@ static void khugepaged_loop(void)
                 if (hpage)
                         put_page(hpage);
 #endif
-                try_to_freeze();
-                if (unlikely(kthread_should_stop()))
-                        break;
-                if (khugepaged_has_work()) {
-                        if (!khugepaged_scan_sleep_millisecs)
-                                continue;
-                        wait_event_freezable_timeout(khugepaged_wait, false,
-                            msecs_to_jiffies(khugepaged_scan_sleep_millisecs));
-                } else if (khugepaged_enabled())
-                        wait_event_freezable(khugepaged_wait,
-                                             khugepaged_wait_event());
+
+                khugepaged_wait_work();
         }
 }