[PATCH 05/12] thp: remove wake_up_interruptible in the exit path

[Xiao Guangrong]

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 <xiaoguangr...@linux.vnet.ibm.com>
---
 mm/huge_memory.c |   35 +++++++++++++++++++++--------------
 1 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index b218700..86f71af 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;
        }
@@ -2236,7 +2234,7 @@ 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)
@@ -2303,6 +2301,24 @@ 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;
@@ -2327,17 +2343,8 @@ 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();
        }
 }

-- 
1.7.7.6

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