[merged] kernel-workqueue-clarify-wq_worker_last_func-caller-requirements.patch removed from -mm tree

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The patch titled
     Subject: kernel: workqueue: clarify wq_worker_last_func() caller requirements
has been removed from the -mm tree.  Its filename was
     kernel-workqueue-clarify-wq_worker_last_func-caller-requirements.patch

This patch was dropped because it was merged into mainline or a subsystem tree

------------------------------------------------------
From: Johannes Weiner <hannes@xxxxxxxxxxx>
Subject: kernel: workqueue: clarify wq_worker_last_func() caller requirements

This function can only be called safely from very specific scheduler
contexts. Document those.

Link: http://lkml.kernel.org/r/20190206150528.31198-1-hannes@xxxxxxxxxxx
Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>
Suggested-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---


--- a/kernel/workqueue.c~kernel-workqueue-clarify-wq_worker_last_func-caller-requirements
+++ a/kernel/workqueue.c
@@ -920,6 +920,16 @@ struct task_struct *wq_worker_sleeping(s
  * 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.
_

Patches currently in -mm which might be from hannes@xxxxxxxxxxx are





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