io_uring: trace local task work run

Add tracing for io_run_local_task_work

Signed-off-by: Dylan Yudaken <dylany@fb.com>
Link: https://lore.kernel.org/r/20220830125013.570060-8-dylany@fb.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

include/trace/events/io_uring.h

@@ -655,6 +655,35 @@ TRACE_EVENT(io_uring_short_write,
 			  __entry->wanted, __entry->got)
 );
 
+/*
+ * io_uring_local_work_run - ran ring local task work
+ *
+ * @tctx:		pointer to a io_uring_ctx
+ * @count:		how many functions it ran
+ * @loops:		how many loops it ran
+ *
+ */
+TRACE_EVENT(io_uring_local_work_run,
+
+	TP_PROTO(void *ctx, int count, unsigned int loops),
+
+	TP_ARGS(ctx, count, loops),
+
+	TP_STRUCT__entry (
+		__field(void *,		ctx	)
+		__field(int,		count	)
+		__field(unsigned int,	loops	)
+	),
+
+	TP_fast_assign(
+		__entry->ctx		= ctx;
+		__entry->count		= count;
+		__entry->loops		= loops;
+	),
+
+	TP_printk("ring %p, count %d, loops %u", __entry->ctx, __entry->count, __entry->loops)
+);
+
 #endif /* _TRACE_IO_URING_H */
 
 /* This part must be outside protection */

io_uring/io_uring.c

@@ -1168,6 +1168,7 @@ int io_run_local_work(struct io_ring_ctx *ctx)
 	struct llist_node fake;
 	struct llist_node *current_final = NULL;
 	int ret;
+	unsigned int loops = 1;
 
 	if (unlikely(ctx->submitter_task != current)) {
 		/* maybe this is before any submissions */
@@ -1197,6 +1198,7 @@ int io_run_local_work(struct io_ring_ctx *ctx)
 
 	node = io_llist_cmpxchg(&ctx->work_llist, &fake, NULL);
 	if (node != &fake) {
+		loops++;
 		current_final = &fake;
 		node = io_llist_xchg(&ctx->work_llist, &fake);
 		goto again;
@@ -1206,6 +1208,7 @@ int io_run_local_work(struct io_ring_ctx *ctx)
 		io_submit_flush_completions(ctx);
 		mutex_unlock(&ctx->uring_lock);
 	}
+	trace_io_uring_local_work_run(ctx, ret, loops);
 	return ret;
 }