diff options
Diffstat (limited to 'kernel/sched/wait.c')
| -rw-r--r-- | kernel/sched/wait.c | 37 |
1 files changed, 27 insertions, 10 deletions
diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index c1e566a114ca..ba059fbfc53a 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -169,7 +169,6 @@ EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark); * __wake_up_sync_key - wake up threads blocked on a waitqueue. * @wq_head: the waitqueue * @mode: which threads - * @nr_exclusive: how many wake-one or wake-many threads to wake up * @key: opaque value to be passed to wakeup targets * * The sync wakeup differs that the waker knows that it will schedule @@ -183,26 +182,44 @@ EXPORT_SYMBOL_GPL(__wake_up_locked_key_bookmark); * accessing the task state. */ void __wake_up_sync_key(struct wait_queue_head *wq_head, unsigned int mode, - int nr_exclusive, void *key) + void *key) { - int wake_flags = 1; /* XXX WF_SYNC */ - if (unlikely(!wq_head)) return; - if (unlikely(nr_exclusive != 1)) - wake_flags = 0; - - __wake_up_common_lock(wq_head, mode, nr_exclusive, wake_flags, key); + __wake_up_common_lock(wq_head, mode, 1, WF_SYNC, key); } EXPORT_SYMBOL_GPL(__wake_up_sync_key); +/** + * __wake_up_locked_sync_key - wake up a thread blocked on a locked waitqueue. + * @wq_head: the waitqueue + * @mode: which threads + * @key: opaque value to be passed to wakeup targets + * + * The sync wakeup differs in that the waker knows that it will schedule + * away soon, so while the target thread will be woken up, it will not + * be migrated to another CPU - ie. the two threads are 'synchronized' + * with each other. This can prevent needless bouncing between CPUs. + * + * On UP it can prevent extra preemption. + * + * If this function wakes up a task, it executes a full memory barrier before + * accessing the task state. + */ +void __wake_up_locked_sync_key(struct wait_queue_head *wq_head, + unsigned int mode, void *key) +{ + __wake_up_common(wq_head, mode, 1, WF_SYNC, key, NULL); +} +EXPORT_SYMBOL_GPL(__wake_up_locked_sync_key); + /* * __wake_up_sync - see __wake_up_sync_key() */ -void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode, int nr_exclusive) +void __wake_up_sync(struct wait_queue_head *wq_head, unsigned int mode) { - __wake_up_sync_key(wq_head, mode, nr_exclusive, NULL); + __wake_up_sync_key(wq_head, mode, NULL); } EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |