1 files changed, 10 insertions, 0 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 69bd8083930c..7abbeed13421 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -920,6 +920,16 @@ struct task_struct *wq_worker_sleeping(struct task_struct *task)
  * CONTEXT:
  * spin_lock_irq(rq->lock)
  *
+ * This function is called during schedule() when a kworker is going
+ * to sleep. It's used by psi to identify aggregation workers during
+ * dequeuing, to allow periodic aggregation to shut-off when that
+ * worker is the last task in the system or cgroup to go to sleep.
+ *
+ * As this function doesn't involve any workqueue-related locking, it
+ * only returns stable values when called from inside the scheduler's
+ * queuing and dequeuing paths, when @task, which must be a kworker,
+ * is guaranteed to not be processing any works.
+ *
  * Return:
  * The last work function %current executed as a worker, NULL if it
  * hasn't executed any work yet.