This is a note to let you know that I've just added the patch titled
kthread: add kthread_work tracepoints
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
kthread-add-kthread_work-tracepoints.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4d2d748f6b5ab944ccf205fdce8a9f101958ce85
Author: Rob Clark <robdclark@xxxxxxxxxxxx>
Date: Mon Dec 14 19:03:14 2020 -0800
kthread: add kthread_work tracepoints
[ Upstream commit f630c7c6f10546ebff15c3a856e7949feb7a2372 ]
While migrating some code from wq to kthread_worker, I found that I missed
the execute_start/end tracepoints. So add similar tracepoints for
kthread_work. And for completeness, queue_work tracepoint (although this
one differs slightly from the matching workqueue tracepoint).
Link: https://lkml.kernel.org/r/20201010180323.126634-1-robdclark@xxxxxxxxx
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
Cc: Rob Clark <robdclark@xxxxxxxxxxxx>
Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: "Peter Zijlstra (Intel)" <peterz@xxxxxxxxxxxxx>
Cc: Phil Auld <pauld@xxxxxxxxxx>
Cc: Valentin Schneider <valentin.schneider@xxxxxxx>
Cc: Thara Gopinath <thara.gopinath@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Vincent Donnefort <vincent.donnefort@xxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Jens Axboe <axboe@xxxxxxxxx>
Cc: Marcelo Tosatti <mtosatti@xxxxxxxxxx>
Cc: Frederic Weisbecker <frederic@xxxxxxxxxx>
Cc: Ilias Stamatis <stamatis.iliass@xxxxxxxxx>
Cc: Liang Chen <cl@xxxxxxxxxxxxxx>
Cc: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: "J. Bruce Fields" <bfields@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Stable-dep-of: e16c7b07784f ("kthread: fix task state in kthread worker if being frozen")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index 9a4bdfadab077..a4eb7bc6fcf5b 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -5,6 +5,7 @@
#if !defined(_TRACE_SCHED_H) || defined(TRACE_HEADER_MULTI_READ)
#define _TRACE_SCHED_H
+#include <linux/kthread.h>
#include <linux/sched/numa_balancing.h>
#include <linux/tracepoint.h>
#include <linux/binfmts.h>
@@ -51,6 +52,89 @@ TRACE_EVENT(sched_kthread_stop_ret,
TP_printk("ret=%d", __entry->ret)
);
+/**
+ * sched_kthread_work_queue_work - called when a work gets queued
+ * @worker: pointer to the kthread_worker
+ * @work: pointer to struct kthread_work
+ *
+ * This event occurs when a work is queued immediately or once a
+ * delayed work is actually queued (ie: once the delay has been
+ * reached).
+ */
+TRACE_EVENT(sched_kthread_work_queue_work,
+
+ TP_PROTO(struct kthread_worker *worker,
+ struct kthread_work *work),
+
+ TP_ARGS(worker, work),
+
+ TP_STRUCT__entry(
+ __field( void *, work )
+ __field( void *, function)
+ __field( void *, worker)
+ ),
+
+ TP_fast_assign(
+ __entry->work = work;
+ __entry->function = work->func;
+ __entry->worker = worker;
+ ),
+
+ TP_printk("work struct=%p function=%ps worker=%p",
+ __entry->work, __entry->function, __entry->worker)
+);
+
+/**
+ * sched_kthread_work_execute_start - called immediately before the work callback
+ * @work: pointer to struct kthread_work
+ *
+ * Allows to track kthread work execution.
+ */
+TRACE_EVENT(sched_kthread_work_execute_start,
+
+ TP_PROTO(struct kthread_work *work),
+
+ TP_ARGS(work),
+
+ TP_STRUCT__entry(
+ __field( void *, work )
+ __field( void *, function)
+ ),
+
+ TP_fast_assign(
+ __entry->work = work;
+ __entry->function = work->func;
+ ),
+
+ TP_printk("work struct %p: function %ps", __entry->work, __entry->function)
+);
+
+/**
+ * sched_kthread_work_execute_end - called immediately after the work callback
+ * @work: pointer to struct work_struct
+ * @function: pointer to worker function
+ *
+ * Allows to track workqueue execution.
+ */
+TRACE_EVENT(sched_kthread_work_execute_end,
+
+ TP_PROTO(struct kthread_work *work, kthread_work_func_t function),
+
+ TP_ARGS(work, function),
+
+ TP_STRUCT__entry(
+ __field( void *, work )
+ __field( void *, function)
+ ),
+
+ TP_fast_assign(
+ __entry->work = work;
+ __entry->function = function;
+ ),
+
+ TP_printk("work struct %p: function %ps", __entry->work, __entry->function)
+);
+
/*
* Tracepoint for waking up a task:
*/
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 9750f4f7f9010..f69aa5da3b53e 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -696,8 +696,15 @@ int kthread_worker_fn(void *worker_ptr)
spin_unlock_irq(&worker->lock);
if (work) {
+ kthread_work_func_t func = work->func;
__set_current_state(TASK_RUNNING);
+ trace_sched_kthread_work_execute_start(work);
work->func(work);
+ /*
+ * Avoid dereferencing work after this point. The trace
+ * event only cares about the address.
+ */
+ trace_sched_kthread_work_execute_end(work, func);
} else if (!freezing(current))
schedule();
@@ -826,6 +833,8 @@ static void kthread_insert_work(struct kthread_worker *worker,
{
kthread_insert_work_sanity_check(worker, work);
+ trace_sched_kthread_work_queue_work(worker, work);
+
list_add_tail(&work->node, pos);
work->worker = worker;
if (!worker->current_work && likely(worker->task))
