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

Pull scheduler changes from Ingo Molnar:
 "Main changes:

   - scheduler side full-dynticks (user-space execution is undisturbed
     and receives no timer IRQs) preparation changes that convert the
     cputime accounting code to be full-dynticks ready, from Frederic
     Weisbecker.

   - Initial sched.h split-up changes, by Clark Williams

   - select_idle_sibling() performance improvement by Mike Galbraith:

        " 1 tbench pair (worst case) in a 10 core + SMT package:

          pre   15.22 MB/sec 1 procs
          post 252.01 MB/sec 1 procs "

  - sched_rr_get_interval() ABI fix/change.  We think this detail is not
    used by apps (so it's not an ABI in practice), but lets keep it
    under observation.

  - misc RT scheduling cleanups, optimizations"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
  sched/rt: Add <linux/sched/rt.h> header to <linux/init_task.h>
  cputime: Remove irqsave from seqlock readers
  sched, powerpc: Fix sched.h split-up build failure
  cputime: Restore CPU_ACCOUNTING config defaults for PPC64
  sched/rt: Move rt specific bits into new header file
  sched/rt: Add a tuning knob to allow changing SCHED_RR timeslice
  sched: Move sched.h sysctl bits into separate header
  sched: Fix signedness bug in yield_to()
  sched: Fix select_idle_sibling() bouncing cow syndrome
  sched/rt: Further simplify pick_rt_task()
  sched/rt: Do not account zero delta_exec in update_curr_rt()
  cputime: Safely read cputime of full dynticks CPUs
  kvm: Prepare to add generic guest entry/exit callbacks
  cputime: Use accessors to read task cputime stats
  cputime: Allow dynamic switch between tick/virtual based cputime accounting
  cputime: Generic on-demand virtual cputime accounting
  cputime: Move default nsecs_to_cputime() to jiffies based cputime file
  cputime: Librarize per nsecs resolution cputime definitions
  cputime: Avoid multiplication overflow on utime scaling
  context_tracking: Export context state for generic vtime
  ...

Fix up conflict in kernel/context_tracking.c due to comment additions.

1 files changed, 17 insertions, 9 deletions

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 4f02b2847357..127a2c4cf4ab 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -7,6 +7,8 @@
 
 #include <linux/slab.h>
 
+int sched_rr_timeslice = RR_TIMESLICE;
+
 static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
 
 struct rt_bandwidth def_rt_bandwidth;
@@ -925,8 +927,8 @@ static void update_curr_rt(struct rq *rq)
                 return;
 
         delta_exec = rq->clock_task - curr->se.exec_start;
-        if (unlikely((s64)delta_exec < 0))
-                delta_exec = 0;
+        if (unlikely((s64)delta_exec <= 0))
+                return;
 
         schedstat_set(curr->se.statistics.exec_max,
                       max(curr->se.statistics.exec_max, delta_exec));
@@ -1427,8 +1429,7 @@ static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
 static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
 {
         if (!task_running(rq, p) &&
-            (cpu < 0 || cpumask_test_cpu(cpu, tsk_cpus_allowed(p))) &&
-            (p->nr_cpus_allowed > 1))
+            cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
                 return 1;
         return 0;
 }
@@ -1889,8 +1890,11 @@ static void switched_from_rt(struct rq *rq, struct task_struct *p)
          * we may need to handle the pulling of RT tasks
          * now.
          */
-        if (p->on_rq && !rq->rt.rt_nr_running)
-                pull_rt_task(rq);
+        if (!p->on_rq || rq->rt.rt_nr_running)
+                return;
+
+        if (pull_rt_task(rq))
+                resched_task(rq->curr);
 }
 
 void init_sched_rt_class(void)
@@ -1985,7 +1989,11 @@ static void watchdog(struct rq *rq, struct task_struct *p)
         if (soft != RLIM_INFINITY) {
                 unsigned long next;
 
-                p->rt.timeout++;
+                if (p->rt.watchdog_stamp != jiffies) {
+                        p->rt.timeout++;
+                        p->rt.watchdog_stamp = jiffies;
+                }
+
                 next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
                 if (p->rt.timeout > next)
                         p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
@@ -2010,7 +2018,7 @@ static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
         if (--p->rt.time_slice)
                 return;
 
-        p->rt.time_slice = RR_TIMESLICE;
+        p->rt.time_slice = sched_rr_timeslice;
 
         /*
          * Requeue to the end of queue if we (and all of our ancestors) are the
@@ -2041,7 +2049,7 @@ static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
          * Time slice is 0 for SCHED_FIFO tasks
          */
         if (task->policy == SCHED_RR)
-                return RR_TIMESLICE;
+                return sched_rr_timeslice;
         else
                 return 0;
 }