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-rw-r--r--kernel/workqueue.c10
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.