On Tue 15-11-22 17:45:52, Gabriel Krisman Bertazi wrote:
> Sbitmap code will need to know how many waiters were actually woken for
> its batched wakeups implementation. Return the number of woken
> exclusive waiters from __wake_up() to facilitate that.
>
> Suggested-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: Gabriel Krisman Bertazi <krisman@xxxxxxx>
Looks good. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
Honza
> ---
> include/linux/wait.h | 2 +-
> kernel/sched/wait.c | 18 +++++++++++-------
> 2 files changed, 12 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/wait.h b/include/linux/wait.h
> index 7f5a51aae0a7..a0307b516b09 100644
> --- a/include/linux/wait.h
> +++ b/include/linux/wait.h
> @@ -209,7 +209,7 @@ __remove_wait_queue(struct wait_queue_head *wq_head, struct wait_queue_entry *wq
> list_del(&wq_entry->entry);
> }
>
> -void __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
> +int __wake_up(struct wait_queue_head *wq_head, unsigned int mode, int nr, void *key);
> void __wake_up_locked_key(struct wait_queue_head *wq_head, unsigned int mode, void *key);
> void __wake_up_locked_key_bookmark(struct wait_queue_head *wq_head,
> unsigned int mode, void *key, wait_queue_entry_t *bookmark);
> diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c
> index 9860bb9a847c..133b74730738 100644
> --- a/kernel/sched/wait.c
> +++ b/kernel/sched/wait.c
> @@ -121,11 +121,12 @@ static int __wake_up_common(struct wait_queue_head *wq_head, unsigned int mode,
> return nr_exclusive;
> }
>
> -static void __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int mode,
> +static int __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int mode,
> int nr_exclusive, int wake_flags, void *key)
> {
> unsigned long flags;
> wait_queue_entry_t bookmark;
> + int remaining = nr_exclusive;
>
> bookmark.flags = 0;
> bookmark.private = NULL;
> @@ -134,10 +135,12 @@ static void __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int
>
> do {
> spin_lock_irqsave(&wq_head->lock, flags);
> - nr_exclusive = __wake_up_common(wq_head, mode, nr_exclusive,
> + remaining = __wake_up_common(wq_head, mode, remaining,
> wake_flags, key, &bookmark);
> spin_unlock_irqrestore(&wq_head->lock, flags);
> } while (bookmark.flags & WQ_FLAG_BOOKMARK);
> +
> + return nr_exclusive - remaining;
> }
>
> /**
> @@ -147,13 +150,14 @@ static void __wake_up_common_lock(struct wait_queue_head *wq_head, unsigned int
> * @nr_exclusive: how many wake-one or wake-many threads to wake up
> * @key: is directly passed to the wakeup function
> *
> - * If this function wakes up a task, it executes a full memory barrier before
> - * accessing the task state.
> + * If this function wakes up a task, it executes a full memory barrier
> + * before accessing the task state. Returns the number of exclusive
> + * tasks that were awaken.
> */
> -void __wake_up(struct wait_queue_head *wq_head, unsigned int mode,
> - int nr_exclusive, void *key)
> +int __wake_up(struct wait_queue_head *wq_head, unsigned int mode,
> + int nr_exclusive, void *key)
> {
> - __wake_up_common_lock(wq_head, mode, nr_exclusive, 0, key);
> + return __wake_up_common_lock(wq_head, mode, nr_exclusive, 0, key);
> }
> EXPORT_SYMBOL(__wake_up);
>
> --
> 2.35.3
>
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
