ANDROID: sched: Add replace_next_task_fair vendor hook in pick_next_task_fair

Add trace_android_rvh_replace_next_task_fair vendor hook in scheduler
to support OEM's need to override the selected task from pick_next_task_fair()
due to situations where important tasks are not picked in time.

Bug: 374011864
Bug: 413566818
Change-Id: I55a0e7e794be77ba32c8adbff7b7eb2d914e4c52
Signed-off-by: Wanwei Jiang <wanwei.jiang@amlogic.com>
[jstultz: reworded commit message]
Signed-off-by: John Stultz <jstultz@google.com>

include/trace/hooks/sched.h

@@ -76,6 +76,10 @@ DECLARE_RESTRICTED_HOOK(android_rvh_setscheduler,
 	TP_PROTO(struct task_struct *p),
 	TP_ARGS(p), 1);
 
+DECLARE_RESTRICTED_HOOK(android_rvh_replace_next_task_fair,
+	TP_PROTO(struct rq *rq, struct task_struct **p, struct task_struct *prev),
+	TP_ARGS(rq, p, prev), 1);
+
 struct sched_group;
 DECLARE_RESTRICTED_HOOK(android_rvh_sched_balance_find_src_group,
 	TP_PROTO(struct sched_group *busiest, struct rq *dst_rq, int *out_balance),

kernel/sched/fair.c

@@ -8953,6 +8953,8 @@ pick_next_task_fair(struct rq *rq, struct task_struct *prev, struct rq_flags *rf
 
 again:
 	p = pick_task_fair(rq);
+	trace_android_rvh_replace_next_task_fair(rq, &p, prev);
+
 	if (!p)
 		goto idle;
 	se = &p->se;

kernel/sched/vendor_hooks.c

@@ -37,6 +37,7 @@ EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_cpu_overutilized);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_sched_setaffinity);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_vh_build_sched_domains);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_check_preempt_tick);
+EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_replace_next_task_fair);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_sched_balance_rt);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_check_preempt_wakeup_fair);
 EXPORT_TRACEPOINT_SYMBOL_GPL(android_rvh_set_cpus_allowed_by_task);