ANDROID: sched: Add trace hook for DL server

Create a trace hook when the DL server is activated.
This allows vendors to debug RT/Fair contention issues
by dumping the following information:

1.The task served by the DL server
2.The status of the DL server

Bug: 436885337

Change-Id: I2157bd22b7d7c80d7ec1eeeba3ec6fb88efa4abd
Signed-off-by: kuyo chang <kuyo.chang@mediatek.com>
Signed-off-by: kuyo chang <kuyo.chang@mediatek.corp-partner.google.com>

include/trace/hooks/sched.h

@@ -531,6 +531,11 @@ DECLARE_RESTRICTED_HOOK(android_rvh_util_fits_cpu,
 		 int cpu, bool *fits, bool *done),
 	TP_ARGS(util, uclamp_min, uclamp_max, cpu, fits, done), 1);
 
+struct sched_dl_entity;
+DECLARE_HOOK(android_vh_dump_dl_server,
+	TP_PROTO(struct sched_dl_entity *dl_se, struct task_struct *p),
+	TP_ARGS(dl_se, p));
+
 /* macro versions of hooks are no longer required */
 
 #endif /* _TRACE_HOOK_SCHED_H */

kernel/sched/deadline.c

@@ -2462,6 +2462,7 @@ again:
 			goto again;
 		}
 		rq->dl_server = dl_se;
+		trace_android_vh_dump_dl_server(dl_se, p);
 	} else {
 		p = dl_task_of(dl_se);
 	}

kernel/sched/vendor_hooks.c

@@ -136,3 +136,4 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_uclamp_validate);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_util_fits_cpu);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_before_pick_task_fair);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_balance_fair);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_dump_dl_server);