Commit 2c1f1a91 authored by Lai Jiangshan's avatar Lai Jiangshan Committed by Tejun Heo
Browse files

workqueue: Change the comments of the synchronization about the idle_list 



The access to idle_list in wq_worker_sleeping() is changed to be
protected by pool->lock, so the comments above idle_list can be changed
to "L:" which is the meaning of "access with pool->lock held".

And the outdated comments in wq_worker_sleeping() is removed since
the function is not called with rq lock held any more, idle_list is
dereferenced with pool lock now.

Signed-off-by: default avatarLai Jiangshan <laijs@linux.alibaba.com>
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 21b195c0

kernel/workqueue.c

+2 −9
Original line number Diff line number Diff line
@@ -162,7 +162,7 @@ struct worker_pool { 
	int			nr_workers;	/* L: total number of workers */

	int			nr_idle;	/* L: currently idle workers */



	struct list_head	idle_list;	/* X: list of idle workers */

	struct list_head	idle_list;	/* L: list of idle workers */

	struct timer_list	idle_timer;	/* L: worker idle timeout */

	struct timer_list	mayday_timer;	/* L: SOS timer for workers */
@@ -826,7 +826,7 @@ static bool too_many_workers(struct worker_pool *pool) 
 * Wake up functions.

 */



/* Return the first idle worker.  Safe with preemption disabled */

/* Return the first idle worker.  Called with pool->lock held. */

static struct worker *first_idle_worker(struct worker_pool *pool)

{

	if (unlikely(list_empty(&pool->idle_list)))
@@ -917,13 +917,6 @@ void wq_worker_sleeping(struct task_struct *task) 
		return;

	}



	/*

	 * NOT_RUNNING is clear.  This means that we're bound to and

	 * running on the local cpu w/ rq lock held and preemption

	 * disabled, which in turn means that none else could be

	 * manipulating idle_list, so dereferencing idle_list without pool

	 * lock is safe.

	 */

	if (atomic_dec_and_test(&pool->nr_running) &&

	    !list_empty(&pool->worklist)) {

		next = first_idle_worker(pool);