1 files changed, 152 insertions, 81 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 2d9ff40f4661..f3b27c6c5153 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -237,9 +237,30 @@ static DEFINE_MUTEX(sched_core_mutex);
 static atomic_t sched_core_count;
 static struct cpumask sched_core_mask;
 
+static void sched_core_lock(int cpu, unsigned long *flags)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int t, i = 0;
+
+	local_irq_save(*flags);
+	for_each_cpu(t, smt_mask)
+		raw_spin_lock_nested(&cpu_rq(t)->__lock, i++);
+}
+
+static void sched_core_unlock(int cpu, unsigned long *flags)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	int t;
+
+	for_each_cpu(t, smt_mask)
+		raw_spin_unlock(&cpu_rq(t)->__lock);
+	local_irq_restore(*flags);
+}
+
 static void __sched_core_flip(bool enabled)
 {
-	int cpu, t, i;
+	unsigned long flags;
+	int cpu, t;
 
 	cpus_read_lock();
 
@@ -250,19 +271,12 @@ static void __sched_core_flip(bool enabled)
 	for_each_cpu(cpu, &sched_core_mask) {
 		const struct cpumask *smt_mask = cpu_smt_mask(cpu);
 
-		i = 0;
-		local_irq_disable();
-		for_each_cpu(t, smt_mask) {
-			/* supports up to SMT8 */
-			raw_spin_lock_nested(&cpu_rq(t)->__lock, i++);
-		}
+		sched_core_lock(cpu, &flags);
 
 		for_each_cpu(t, smt_mask)
 			cpu_rq(t)->core_enabled = enabled;
 
-		for_each_cpu(t, smt_mask)
-			raw_spin_unlock(&cpu_rq(t)->__lock);
-		local_irq_enable();
+		sched_core_unlock(cpu, &flags);
 
 		cpumask_andnot(&sched_core_mask, &sched_core_mask, smt_mask);
 	}
@@ -1981,12 +1995,18 @@ void deactivate_task(struct rq *rq, struct task_struct *p, int flags)
 	dequeue_task(rq, p, flags);
 }
 
-/*
- * __normal_prio - return the priority that is based on the static prio
- */
-static inline int __normal_prio(struct task_struct *p)
+static inline int __normal_prio(int policy, int rt_prio, int nice)
 {
-	return p->static_prio;
+	int prio;
+
+	if (dl_policy(policy))
+		prio = MAX_DL_PRIO - 1;
+	else if (rt_policy(policy))
+		prio = MAX_RT_PRIO - 1 - rt_prio;
+	else
+		prio = NICE_TO_PRIO(nice);
+
+	return prio;
 }
 
 /*
@@ -1998,15 +2018,7 @@ static inline int __normal_prio(struct task_struct *p)
  */
 static inline int normal_prio(struct task_struct *p)
 {
-	int prio;
-
-	if (task_has_dl_policy(p))
-		prio = MAX_DL_PRIO-1;
-	else if (task_has_rt_policy(p))
-		prio = MAX_RT_PRIO-1 - p->rt_priority;
-	else
-		prio = __normal_prio(p);
-	return prio;
+	return __normal_prio(p->policy, p->rt_priority, PRIO_TO_NICE(p->static_prio));
 }
 
 /*
@@ -4099,7 +4111,7 @@ int sched_fork(unsigned long clone_flags, struct task_struct *p)
 		} else if (PRIO_TO_NICE(p->static_prio) < 0)
 			p->static_prio = NICE_TO_PRIO(0);
 
-		p->prio = p->normal_prio = __normal_prio(p);
+		p->prio = p->normal_prio = p->static_prio;
 		set_load_weight(p, false);
 
 		/*
@@ -5738,35 +5750,109 @@ void queue_core_balance(struct rq *rq)
 	queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance);
 }
 
-static inline void sched_core_cpu_starting(unsigned int cpu)
+static void sched_core_cpu_starting(unsigned int cpu)
 {
 	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
-	struct rq *rq, *core_rq = NULL;
-	int i;
+	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;
+	unsigned long flags;
+	int t;
+
+	sched_core_lock(cpu, &flags);
 
-	core_rq = cpu_rq(cpu)->core;
+	WARN_ON_ONCE(rq->core != rq);
 
-	if (!core_rq) {
-		for_each_cpu(i, smt_mask) {
-			rq = cpu_rq(i);
-			if (rq->core && rq->core == rq)
-				core_rq = rq;
+	/* if we're the first, we'll be our own leader */
+	if (cpumask_weight(smt_mask) == 1)
+		goto unlock;
+
+	/* find the leader */
+	for_each_cpu(t, smt_mask) {
+		if (t == cpu)
+			continue;
+		rq = cpu_rq(t);
+		if (rq->core == rq) {
+			core_rq = rq;
+			break;
 		}
+	}
 
-		if (!core_rq)
-			core_rq = cpu_rq(cpu);
+	if (WARN_ON_ONCE(!core_rq)) /* whoopsie */
+		goto unlock;
 
-		for_each_cpu(i, smt_mask) {
-			rq = cpu_rq(i);
+	/* install and validate core_rq */
+	for_each_cpu(t, smt_mask) {
+		rq = cpu_rq(t);
 
-			WARN_ON_ONCE(rq->core && rq->core != core_rq);
+		if (t == cpu)
 			rq->core = core_rq;
-		}
+
+		WARN_ON_ONCE(rq->core != core_rq);
+	}
+
+unlock:
+	sched_core_unlock(cpu, &flags);
+}
+
+static void sched_core_cpu_deactivate(unsigned int cpu)
+{
+	const struct cpumask *smt_mask = cpu_smt_mask(cpu);
+	struct rq *rq = cpu_rq(cpu), *core_rq = NULL;
+	unsigned long flags;
+	int t;
+
+	sched_core_lock(cpu, &flags);
+
+	/* if we're the last man standing, nothing to do */
+	if (cpumask_weight(smt_mask) == 1) {
+		WARN_ON_ONCE(rq->core != rq);
+		goto unlock;
 	}
+
+	/* if we're not the leader, nothing to do */
+	if (rq->core != rq)
+		goto unlock;
+
+	/* find a new leader */
+	for_each_cpu(t, smt_mask) {
+		if (t == cpu)
+			continue;
+		core_rq = cpu_rq(t);
+		break;
+	}
+
+	if (WARN_ON_ONCE(!core_rq)) /* impossible */
+		goto unlock;
+
+	/* copy the shared state to the new leader */
+	core_rq->core_task_seq      = rq->core_task_seq;
+	core_rq->core_pick_seq      = rq->core_pick_seq;
+	core_rq->core_cookie        = rq->core_cookie;
+	core_rq->core_forceidle     = rq->core_forceidle;
+	core_rq->core_forceidle_seq = rq->core_forceidle_seq;
+
+	/* install new leader */
+	for_each_cpu(t, smt_mask) {
+		rq = cpu_rq(t);
+		rq->core = core_rq;
+	}
+
+unlock:
+	sched_core_unlock(cpu, &flags);
 }
+
+static inline void sched_core_cpu_dying(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->core != rq)
+		rq->core = rq;
+}
+
 #else /* !CONFIG_SCHED_CORE */
 
 static inline void sched_core_cpu_starting(unsigned int cpu) {}
+static inline void sched_core_cpu_deactivate(unsigned int cpu) {}
+static inline void sched_core_cpu_dying(unsigned int cpu) {}
 
 static struct task_struct *
 pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
@@ -6341,6 +6427,18 @@ int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flag
 }
 EXPORT_SYMBOL(default_wake_function);
 
+static void __setscheduler_prio(struct task_struct *p, int prio)
+{
+	if (dl_prio(prio))
+		p->sched_class = &dl_sched_class;
+	else if (rt_prio(prio))
+		p->sched_class = &rt_sched_class;
+	else
+		p->sched_class = &fair_sched_class;
+
+	p->prio = prio;
+}
+
 #ifdef CONFIG_RT_MUTEXES
 
 static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
@@ -6456,22 +6554,19 @@ void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
 		} else {
 			p->dl.pi_se = &p->dl;
 		}
-		p->sched_class = &dl_sched_class;
 	} else if (rt_prio(prio)) {
 		if (dl_prio(oldprio))
 			p->dl.pi_se = &p->dl;
 		if (oldprio < prio)
 			queue_flag |= ENQUEUE_HEAD;
-		p->sched_class = &rt_sched_class;
 	} else {
 		if (dl_prio(oldprio))
 			p->dl.pi_se = &p->dl;
 		if (rt_prio(oldprio))
 			p->rt.timeout = 0;
-		p->sched_class = &fair_sched_class;
 	}
 
-	p->prio = prio;
+	__setscheduler_prio(p, prio);
 
 	if (queued)
 		enqueue_task(rq, p, queue_flag);
@@ -6824,35 +6919,6 @@ static void __setscheduler_params(struct task_struct *p,
 	set_load_weight(p, true);
 }
 
-/* Actually do priority change: must hold pi & rq lock. */
-static void __setscheduler(struct rq *rq, struct task_struct *p,
-			   const struct sched_attr *attr, bool keep_boost)
-{
-	/*
-	 * If params can't change scheduling class changes aren't allowed
-	 * either.
-	 */
-	if (attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)
-		return;
-
-	__setscheduler_params(p, attr);
-
-	/*
-	 * Keep a potential priority boosting if called from
-	 * sched_setscheduler().
-	 */
-	p->prio = normal_prio(p);
-	if (keep_boost)
-		p->prio = rt_effective_prio(p, p->prio);
-
-	if (dl_prio(p->prio))
-		p->sched_class = &dl_sched_class;
-	else if (rt_prio(p->prio))
-		p->sched_class = &rt_sched_class;
-	else
-		p->sched_class = &fair_sched_class;
-}
-
 /*
  * Check the target process has a UID that matches the current process's:
  */
@@ -6873,10 +6939,8 @@ static int __sched_setscheduler(struct task_struct *p,
 				const struct sched_attr *attr,
 				bool user, bool pi)
 {
-	int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 :
-		      MAX_RT_PRIO - 1 - attr->sched_priority;
-	int retval, oldprio, oldpolicy = -1, queued, running;
-	int new_effective_prio, policy = attr->sched_policy;
+	int oldpolicy = -1, policy = attr->sched_policy;
+	int retval, oldprio, newprio, queued, running;
 	const struct sched_class *prev_class;
 	struct callback_head *head;
 	struct rq_flags rf;
@@ -7074,6 +7138,7 @@ change:
 	p->sched_reset_on_fork = reset_on_fork;
 	oldprio = p->prio;
 
+	newprio = __normal_prio(policy, attr->sched_priority, attr->sched_nice);
 	if (pi) {
 		/*
 		 * Take priority boosted tasks into account. If the new
@@ -7082,8 +7147,8 @@ change:
 		 * the runqueue. This will be done when the task deboost
 		 * itself.
 		 */
-		new_effective_prio = rt_effective_prio(p, newprio);
-		if (new_effective_prio == oldprio)
+		newprio = rt_effective_prio(p, newprio);
+		if (newprio == oldprio)
 			queue_flags &= ~DEQUEUE_MOVE;
 	}
 
@@ -7096,7 +7161,10 @@ change:
 
 	prev_class = p->sched_class;
 
-	__setscheduler(rq, p, attr, pi);
+	if (!(attr->sched_flags & SCHED_FLAG_KEEP_PARAMS)) {
+		__setscheduler_params(p, attr);
+		__setscheduler_prio(p, newprio);
+	}
 	__setscheduler_uclamp(p, attr);
 
 	if (queued) {
@@ -8727,6 +8795,8 @@ int sched_cpu_deactivate(unsigned int cpu)
 	 */
 	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
 		static_branch_dec_cpuslocked(&sched_smt_present);
+
+	sched_core_cpu_deactivate(cpu);
 #endif
 
 	if (!sched_smp_initialized)
@@ -8831,6 +8901,7 @@ int sched_cpu_dying(unsigned int cpu)
 	calc_load_migrate(rq);
 	update_max_interval();
 	hrtick_clear(rq);
+	sched_core_cpu_dying(cpu);
 	return 0;
 }
 #endif
@@ -9042,7 +9113,7 @@ void __init sched_init(void)
 		atomic_set(&rq->nr_iowait, 0);
 
 #ifdef CONFIG_SCHED_CORE
-		rq->core = NULL;
+		rq->core = rq;
 		rq->core_pick = NULL;
 		rq->core_enabled = 0;
 		rq->core_tree = RB_ROOT;