Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle are:

   - Various NUMA scheduling updates: harmonize the load-balancer and
     NUMA placement logic to not work against each other. The intended
     result is better locality, better utilization and fewer migrations.

   - Introduce Thermal Pressure tracking and optimizations, to improve
     task placement on thermally overloaded systems.

   - Implement frequency invariant scheduler accounting on (some) x86
     CPUs. This is done by observing and sampling the 'recent' CPU
     frequency average at ~tick boundaries. The CPU provides this data
     via the APERF/MPERF MSRs. This hopefully makes our capacity
     estimates more precise and keeps tasks on the same CPU better even
     if it might seem overloaded at a lower momentary frequency. (As
     usual, turbo mode is a complication that we resolve by observing
     the maximum frequency and renormalizing to it.)

   - Add asymmetric CPU capacity wakeup scan to improve capacity
     utilization on asymmetric topologies. (big.LITTLE systems)

   - PSI fixes and optimizations.

   - RT scheduling capacity awareness fixes & improvements.

   - Optimize the CONFIG_RT_GROUP_SCHED constraints code.

   - Misc fixes, cleanups and optimizations - see the changelog for
     details"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (62 commits)
  threads: Update PID limit comment according to futex UAPI change
  sched/fair: Fix condition of avg_load calculation
  sched/rt: cpupri_find: Trigger a full search as fallback
  kthread: Do not preempt current task if it is going to call schedule()
  sched/fair: Improve spreading of utilization
  sched: Avoid scale real weight down to zero
  psi: Move PF_MEMSTALL out of task->flags
  MAINTAINERS: Add maintenance information for psi
  psi: Optimize switching tasks inside shared cgroups
  psi: Fix cpu.pressure for cpu.max and competing cgroups
  sched/core: Distribute tasks within affinity masks
  sched/fair: Fix enqueue_task_fair warning
  thermal/cpu-cooling, sched/core: Move the arch_set_thermal_pressure() API to generic scheduler code
  sched/rt: Remove unnecessary push for unfit tasks
  sched/rt: Allow pulling unfitting task
  sched/rt: Optimize cpupri_find() on non-heterogenous systems
  sched/rt: Re-instate old behavior in select_task_rq_rt()
  sched/rt: cpupri_find: Implement fallback mechanism for !fit case
  sched/fair: Fix reordering of enqueue/dequeue_task_fair()
  sched/fair: Fix runnable_avg for throttled cfs
  ...

1 files changed, 23 insertions, 4 deletions

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1a9983da4408..c1f923d647ee 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -761,7 +761,6 @@ static void set_load_weight(struct task_struct *p, bool update_load)
 	if (task_has_idle_policy(p)) {
 		load->weight = scale_load(WEIGHT_IDLEPRIO);
 		load->inv_weight = WMULT_IDLEPRIO;
-		p->se.runnable_weight = load->weight;
 		return;
 	}
 
@@ -774,7 +773,6 @@ static void set_load_weight(struct task_struct *p, bool update_load)
 	} else {
 		load->weight = scale_load(sched_prio_to_weight[prio]);
 		load->inv_weight = sched_prio_to_wmult[prio];
-		p->se.runnable_weight = load->weight;
 	}
 }
 
@@ -1652,7 +1650,12 @@ static int __set_cpus_allowed_ptr(struct task_struct *p,
 	if (cpumask_equal(p->cpus_ptr, new_mask))
 		goto out;
 
-	dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
+	/*
+	 * Picking a ~random cpu helps in cases where we are changing affinity
+	 * for groups of tasks (ie. cpuset), so that load balancing is not
+	 * immediately required to distribute the tasks within their new mask.
+	 */
+	dest_cpu = cpumask_any_and_distribute(cpu_valid_mask, new_mask);
 	if (dest_cpu >= nr_cpu_ids) {
 		ret = -EINVAL;
 		goto out;
@@ -3578,6 +3581,17 @@ unsigned long long task_sched_runtime(struct task_struct *p)
 	return ns;
 }
 
+DEFINE_PER_CPU(unsigned long, thermal_pressure);
+
+void arch_set_thermal_pressure(struct cpumask *cpus,
+			       unsigned long th_pressure)
+{
+	int cpu;
+
+	for_each_cpu(cpu, cpus)
+		WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
+}
+
 /*
  * This function gets called by the timer code, with HZ frequency.
  * We call it with interrupts disabled.
@@ -3588,12 +3602,16 @@ void scheduler_tick(void)
 	struct rq *rq = cpu_rq(cpu);
 	struct task_struct *curr = rq->curr;
 	struct rq_flags rf;
+	unsigned long thermal_pressure;
 
+	arch_scale_freq_tick();
 	sched_clock_tick();
 
 	rq_lock(rq, &rf);
 
 	update_rq_clock(rq);
+	thermal_pressure = arch_scale_thermal_pressure(cpu_of(rq));
+	update_thermal_load_avg(rq_clock_thermal(rq), rq, thermal_pressure);
 	curr->sched_class->task_tick(rq, curr, 0);
 	calc_global_load_tick(rq);
 	psi_task_tick(rq);
@@ -3671,7 +3689,6 @@ static void sched_tick_remote(struct work_struct *work)
 	if (cpu_is_offline(cpu))
 		goto out_unlock;
 
-	curr = rq->curr;
 	update_rq_clock(rq);
 
 	if (!is_idle_task(curr)) {
@@ -4074,6 +4091,8 @@ static void __sched notrace __schedule(bool preempt)
 		 */
 		++*switch_count;
 
+		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
+
 		trace_sched_switch(preempt, prev, next);
 
 		/* Also unlocks the rq: */