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 <longman@xxxxxxxxxx>
---
include/linux/sched.h | 2 +-
kernel/futex.c | 8 +++-----
kernel/sched/core.c | 6 ++++--
3 files changed, 8 insertions(+), 8 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 453143c..eeb6d5a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1038,7 +1038,7 @@ struct wake_q_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);
/*
* sched-domains (multiprocessor balancing) declarations:
diff --git a/kernel/futex.c b/kernel/futex.c
index 5e69c44..4f235e8 100644
--- a/kernel/futex.c
+++ b/kernel/futex.c
@@ -4254,11 +4254,9 @@ 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 966556e..eed7a15 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -449,9 +449,10 @@ 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;
@@ -466,9 +467,10 @@ 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
--
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