[PATCH-tip v5 20/21] sched, TP-futex: Make wake_up_q() return wakeup count

[Waiman Long]

Unlike wake_up_process(), wake_up_q() doesn't tell us how many
tasks have been woken up. This information can sometimes be useful
for tracking purpose. So wake_up_q() is now modified to return that
information.

Signed-off-by: Waiman Long <long...@redhat.com>
---
 include/linux/sched/wake_q.h | 2 +-
 kernel/futex.c               | 8 +++-----
 kernel/sched/core.c          | 6 ++++--
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/include/linux/sched/wake_q.h b/include/linux/sched/wake_q.h
index 9a32f17..2b2bc9d 100644
--- a/include/linux/sched/wake_q.h
+++ b/include/linux/sched/wake_q.h
@@ -49,6 +49,6 @@ static inline void wake_q_init(struct wake_q_head *head)
 
 extern void wake_q_add(struct wake_q_head *head,
                       struct task_struct *task);
-extern void wake_up_q(struct wake_q_head *head);
+extern int wake_up_q(struct wake_q_head *head);
 
 #endif /* _LINUX_SCHED_WAKE_Q_H */
diff --git a/kernel/futex.c b/kernel/futex.c
index 16c63b8..6bf5304 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -4257,11 +4257,9 @@ static int futex_unlock(u32 __user *uaddr, unsigned int 
flags,
 out_put_key:
        put_futex_key(&key);
        if (owner) {
-               /*
-                * No error would have happened if owner defined.
-                */
-               wake_up_q(&wake_q);
-               return ret ? ret : 1;
+               int cnt = wake_up_q(&wake_q);
+
+               return ret ? ret : cnt;
        }
 
        return ret;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 679093d..668a094 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -452,9 +452,10 @@ void wake_q_add(struct wake_q_head *head, struct 
task_struct *task)
        head->lastp = &node->next;
 }
 
-void wake_up_q(struct wake_q_head *head)
+int wake_up_q(struct wake_q_head *head)
 {
        struct wake_q_node *node = head->first;
+       int wakecnt = 0;
 
        while (node != WAKE_Q_TAIL) {
                struct task_struct *task;
@@ -469,9 +470,10 @@ void wake_up_q(struct wake_q_head *head)
                 * wake_up_process() implies a wmb() to pair with the queueing
                 * in wake_q_add() so as not to miss wakeups.
                 */
-               wake_up_process(task);
+               wakecnt += wake_up_process(task);
                put_task_struct(task);
        }
+       return wakecnt;
 }
 
 /*
-- 
1.8.3.1

--
To unsubscribe from this list: send the line "unsubscribe linux-doc" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html