Commit c0ab017d authored by Tejun Heo's avatar Tejun Heo
Browse files

workqueue: Cleanups around process_scheduled_works() 



* Drop the trivial optimization in worker_thread() where it bypasses calling
  process_scheduled_works() if the first work item isn't linked. This is a
  mostly pointless micro optimization and gets in the way of improving the
  work processing path.

* Consolidate pool->watchdog_ts updates in the two callers into
  process_scheduled_works().

Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent bc8b50c2

kernel/workqueue.c

+11 −18
Original line number Diff line number Diff line
@@ -2652,9 +2652,15 @@ __acquires(&pool->lock) 
 */

static void process_scheduled_works(struct worker *worker)

{

	while (!list_empty(&worker->scheduled)) {

		struct work_struct *work = list_first_entry(&worker->scheduled,

						struct work_struct, entry);

	struct work_struct *work;

	bool first = true;



	while ((work = list_first_entry_or_null(&worker->scheduled,

						struct work_struct, entry))) {

		if (first) {

			worker->pool->watchdog_ts = jiffies;

			first = false;

		}

		process_one_work(worker, work);

	}

}
@@ -2735,17 +2741,8 @@ static int worker_thread(void *__worker) 
			list_first_entry(&pool->worklist,

					 struct work_struct, entry);



		pool->watchdog_ts = jiffies;



		if (likely(!(*work_data_bits(work) & WORK_STRUCT_LINKED))) {

			/* optimization path, not strictly necessary */

			process_one_work(worker, work);

			if (unlikely(!list_empty(&worker->scheduled)))

				process_scheduled_works(worker);

		} else {

		move_linked_works(work, &worker->scheduled, NULL);

		process_scheduled_works(worker);

		}

	} while (keep_working(pool));



	worker_set_flags(worker, WORKER_PREP);
@@ -2820,7 +2817,6 @@ static int rescuer_thread(void *__rescuer) 
					struct pool_workqueue, mayday_node);

		struct worker_pool *pool = pwq->pool;

		struct work_struct *work, *n;

		bool first = true;



		__set_current_state(TASK_RUNNING);

		list_del_init(&pwq->mayday_node);
@@ -2838,12 +2834,9 @@ static int rescuer_thread(void *__rescuer) 
		WARN_ON_ONCE(!list_empty(scheduled));

		list_for_each_entry_safe(work, n, &pool->worklist, entry) {

			if (get_work_pwq(work) == pwq) {

				if (first)

					pool->watchdog_ts = jiffies;

				move_linked_works(work, scheduled, &n);

				pwq->stats[PWQ_STAT_RESCUED]++;

			}

			first = false;

		}



		if (!list_empty(scheduled)) {