linux-kernel - [GIT PULL] scheduler fixes

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Date:	Fri, 12 Aug 2016 21:39:59 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
Cc:	linux-kernel@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andrew Morton <akpm@...ux-foundation.org>
Subject: [GIT PULL] scheduler fixes

Linus,

Please pull the latest sched-urgent-for-linus git tree from:

   git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-for-linus

   # HEAD: 26f2c75cd2cf10a6120ef02ca9a94db77cc9c8e0 sched/cputime: Fix omitted ticks passed in parameter

Misc fixes: cputime fixes, two deadline scheduler fixes and a cgroups scheduling 
fix.

 Thanks,

	Ingo

------------------>
Frederic Weisbecker (1):
      sched/cputime: Fix omitted ticks passed in parameter

Giovanni Gherdovich (1):
      sched/cputime: Mitigate performance regression in times()/clock_gettime()

Tommaso Cucinotta (1):
      sched/deadline: Fix wrap-around in DL heap

Wanpeng Li (2):
      sched/deadline: Fix lock pinning warning during CPU hotplug
      sched/cputime: Fix steal time accounting

Xunlei Pang (1):
      sched/fair: Fix typo in sync_throttle()


 kernel/sched/core.c        | 19 +++++++++++++++++++
 kernel/sched/cpudeadline.c |  2 +-
 kernel/sched/cputime.c     | 10 +++++++++-
 kernel/sched/deadline.c    |  5 ++++-
 kernel/sched/fair.c        |  2 +-
 5 files changed, 34 insertions(+), 4 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5c883fe8e440..2a906f20fba7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -74,6 +74,7 @@
 #include <linux/context_tracking.h>
 #include <linux/compiler.h>
 #include <linux/frame.h>
+#include <linux/prefetch.h>
 
 #include <asm/switch_to.h>
 #include <asm/tlb.h>
@@ -2972,6 +2973,23 @@ EXPORT_PER_CPU_SYMBOL(kstat);
 EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
 
 /*
+ * The function fair_sched_class.update_curr accesses the struct curr
+ * and its field curr->exec_start; when called from task_sched_runtime(),
+ * we observe a high rate of cache misses in practice.
+ * Prefetching this data results in improved performance.
+ */
+static inline void prefetch_curr_exec_start(struct task_struct *p)
+{
+#ifdef CONFIG_FAIR_GROUP_SCHED
+	struct sched_entity *curr = (&p->se)->cfs_rq->curr;
+#else
+	struct sched_entity *curr = (&task_rq(p)->cfs)->curr;
+#endif
+	prefetch(curr);
+	prefetch(&curr->exec_start);
+}
+
+/*
  * Return accounted runtime for the task.
  * In case the task is currently running, return the runtime plus current's
  * pending runtime that have not been accounted yet.
@@ -3005,6 +3023,7 @@ unsigned long long task_sched_runtime(struct task_struct *p)
 	 * thread, breaking clock_gettime().
 	 */
 	if (task_current(rq, p) && task_on_rq_queued(p)) {
+		prefetch_curr_exec_start(p);
 		update_rq_clock(rq);
 		p->sched_class->update_curr(rq);
 	}
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 5be58820465c..d4184498c9f5 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -168,7 +168,7 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
 
 	if (old_idx == IDX_INVALID) {
 		cp->size++;
-		cp->elements[cp->size - 1].dl = 0;
+		cp->elements[cp->size - 1].dl = dl;
 		cp->elements[cp->size - 1].cpu = cpu;
 		cp->elements[cpu].idx = cp->size - 1;
 		cpudl_change_key(cp, cp->size - 1, dl);
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 1934f658c036..9858266fb0b3 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -508,13 +508,21 @@ void account_process_tick(struct task_struct *p, int user_tick)
  */
 void account_idle_ticks(unsigned long ticks)
 {
+	cputime_t cputime, steal;
 
 	if (sched_clock_irqtime) {
 		irqtime_account_idle_ticks(ticks);
 		return;
 	}
 
-	account_idle_time(jiffies_to_cputime(ticks));
+	cputime = jiffies_to_cputime(ticks);
+	steal = steal_account_process_time(cputime);
+
+	if (steal >= cputime)
+		return;
+
+	cputime -= steal;
+	account_idle_time(cputime);
 }
 
 /*
diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index fcb7f0217ff4..1ce8867283dc 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -658,8 +658,11 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
 	 *
 	 * XXX figure out if select_task_rq_dl() deals with offline cpus.
 	 */
-	if (unlikely(!rq->online))
+	if (unlikely(!rq->online)) {
+		lockdep_unpin_lock(&rq->lock, rf.cookie);
 		rq = dl_task_offline_migration(rq, p);
+		rf.cookie = lockdep_pin_lock(&rq->lock);
+	}
 
 	/*
 	 * Queueing this task back might have overloaded rq, check if we need
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 4088eedea763..039de34f1521 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4269,7 +4269,7 @@ static void sync_throttle(struct task_group *tg, int cpu)
 	pcfs_rq = tg->parent->cfs_rq[cpu];
 
 	cfs_rq->throttle_count = pcfs_rq->throttle_count;
-	pcfs_rq->throttled_clock_task = rq_clock_task(cpu_rq(cpu));
+	cfs_rq->throttled_clock_task = rq_clock_task(cpu_rq(cpu));
 }
 
 /* conditionally throttle active cfs_rq's from put_prev_entity() */