Revert "sched: Move psi_account_irqtime() out of update_rq_clock_task() hotpath"

This reverts commit bfaf0990f1 which is
commit ddae0ca2a8fe12d0e24ab10ba759c3fbd755ada8 upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: I8853ca9becfb9c32a846a41d5866dc4070a15b90
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

kernel/sched/core.c

@@ -721,6 +721,7 @@ static void update_rq_clock_task(struct rq *rq, s64 delta)
 
 	rq->prev_irq_time += irq_delta;
 	delta -= irq_delta;
+	psi_account_irqtime(rq->curr, irq_delta);
 #endif
 #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
 	if (static_key_false((&paravirt_steal_rq_enabled))) {
@@ -5678,7 +5679,7 @@ void scheduler_tick(void)
 {
 	int cpu = smp_processor_id();
 	struct rq *rq = cpu_rq(cpu);
-	struct task_struct *curr;
+	struct task_struct *curr = rq->curr;
 	struct rq_flags rf;
 	unsigned long thermal_pressure;
 	u64 resched_latency;
@@ -5690,9 +5691,6 @@ void scheduler_tick(void)
 
 	rq_lock(rq, &rf);
 
-	curr = rq->curr;
-	psi_account_irqtime(rq, curr, NULL);
-
 	update_rq_clock(rq);
 	trace_android_rvh_tick_entry(rq);
 
@@ -6738,7 +6736,6 @@ static void __sched notrace __schedule(unsigned int sched_mode)
 		++*switch_count;
 
 		migrate_disable_switch(rq, prev);
-		psi_account_irqtime(rq, prev, next);
 		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
 
 		trace_sched_switch(sched_mode & SM_MASK_PREEMPT, prev, next, prev_state);

kernel/sched/psi.c

@@ -737,7 +737,6 @@ static void psi_group_change(struct psi_group *group, int cpu,
 	enum psi_states s;
 	u32 state_mask;
 
-	lockdep_assert_rq_held(cpu_rq(cpu));
 	groupc = per_cpu_ptr(group->pcpu, cpu);
 
 	/*
@@ -956,29 +955,19 @@ void psi_task_switch(struct task_struct *prev, struct task_struct *next,
 }
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
-void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_struct *prev)
+void psi_account_irqtime(struct task_struct *task, u32 delta)
 {
-	int cpu = task_cpu(curr);
+	int cpu = task_cpu(task);
 	struct psi_group *group;
 	struct psi_group_cpu *groupc;
-	u64 now, irq;
-	s64 delta;
+	u64 now;
 
-	if (!curr->pid)
-		return;
-
-	lockdep_assert_rq_held(rq);
-	group = task_psi_group(curr);
-	if (prev && task_psi_group(prev) == group)
+	if (!task->pid)
 		return;
 
 	now = cpu_clock(cpu);
-	irq = irq_time_read(cpu);
-	delta = (s64)(irq - rq->psi_irq_time);
-	if (delta < 0)
-		return;
-	rq->psi_irq_time = irq;
 
+	group = task_psi_group(task);
 	do {
 		if (!group->enabled)
 			continue;

kernel/sched/sched.h

@@ -1112,7 +1112,6 @@ struct rq {
 
 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
 	u64			prev_irq_time;
-	u64			psi_irq_time;
 #endif
 #ifdef CONFIG_PARAVIRT
 	u64			prev_steal_time;

kernel/sched/stats.h

@@ -110,12 +110,8 @@ __schedstats_from_se(struct sched_entity *se)
 void psi_task_change(struct task_struct *task, int clear, int set);
 void psi_task_switch(struct task_struct *prev, struct task_struct *next,
 		     bool sleep);
-#ifdef CONFIG_IRQ_TIME_ACCOUNTING
-void psi_account_irqtime(struct rq *rq, struct task_struct *curr, struct task_struct *prev);
-#else
-static inline void psi_account_irqtime(struct rq *rq, struct task_struct *curr,
-				       struct task_struct *prev) {}
-#endif /*CONFIG_IRQ_TIME_ACCOUNTING */
+void psi_account_irqtime(struct task_struct *task, u32 delta);
+
 /*
  * PSI tracks state that persists across sleeps, such as iowaits and
  * memory stalls. As a result, it has to distinguish between sleeps,
@@ -210,8 +206,7 @@ static inline void psi_ttwu_dequeue(struct task_struct *p) {}
 static inline void psi_sched_switch(struct task_struct *prev,
 				    struct task_struct *next,
 				    bool sleep) {}
-static inline void psi_account_irqtime(struct rq *rq, struct task_struct *curr,
-				       struct task_struct *prev) {}
+static inline void psi_account_irqtime(struct task_struct *task, u32 delta) {}
 #endif /* CONFIG_PSI */
 
 #ifdef CONFIG_SCHED_INFO