Merge git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched

* git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched:
  sched: reorder SCHED_FEAT_ bits
  sched: make sched_nr_latency static
  sched: remove activate_idle_task()
  sched: fix __set_task_cpu() SMP race
  sched: fix SCHED_FIFO tasks & FAIR_GROUP_SCHED
  sched: fix accounting of interrupts during guest execution on s390

2 files changed, 28 insertions, 36 deletions

diff --git a/kernel/sched.c b/kernel/sched.c
index 4fb3532dd7e8..38933cafea8a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -216,15 +216,15 @@ static inline struct task_group *task_group(struct task_struct *p)
 }
 
 /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
-static inline void set_task_cfs_rq(struct task_struct *p)
+static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu)
 {
-        p->se.cfs_rq = task_group(p)->cfs_rq[task_cpu(p)];
-        p->se.parent = task_group(p)->se[task_cpu(p)];
+        p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
+        p->se.parent = task_group(p)->se[cpu];
 }
 
 #else
 
-static inline void set_task_cfs_rq(struct task_struct *p) { }
+static inline void set_task_cfs_rq(struct task_struct *p, unsigned int cpu) { }
 
 #endif  /* CONFIG_FAIR_GROUP_SCHED */
 
@@ -455,18 +455,18 @@ static void update_rq_clock(struct rq *rq)
  */
 enum {
         SCHED_FEAT_NEW_FAIR_SLEEPERS    = 1,
-        SCHED_FEAT_START_DEBIT          = 2,
-        SCHED_FEAT_TREE_AVG             = 4,
-        SCHED_FEAT_APPROX_AVG           = 8,
-        SCHED_FEAT_WAKEUP_PREEMPT       = 16,
+        SCHED_FEAT_WAKEUP_PREEMPT       = 2,
+        SCHED_FEAT_START_DEBIT          = 4,
+        SCHED_FEAT_TREE_AVG             = 8,
+        SCHED_FEAT_APPROX_AVG           = 16,
 };
 
 const_debug unsigned int sysctl_sched_features =
                 SCHED_FEAT_NEW_FAIR_SLEEPERS    * 1 |
+                SCHED_FEAT_WAKEUP_PREEMPT       * 1 |
                 SCHED_FEAT_START_DEBIT          * 1 |
                 SCHED_FEAT_TREE_AVG             * 0 |
-                SCHED_FEAT_APPROX_AVG           * 0 |
-                SCHED_FEAT_WAKEUP_PREEMPT       * 1;
+                SCHED_FEAT_APPROX_AVG           * 0;
 
 #define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
 
@@ -1022,10 +1022,16 @@ unsigned long weighted_cpuload(const int cpu)
 
 static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
 {
+        set_task_cfs_rq(p, cpu);
 #ifdef CONFIG_SMP
+        /*
+         * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
+         * successfuly executed on another CPU. We must ensure that updates of
+         * per-task data have been completed by this moment.
+         */
+        smp_wmb();
         task_thread_info(p)->cpu = cpu;
 #endif
-        set_task_cfs_rq(p);
 }
 
 #ifdef CONFIG_SMP
@@ -3390,10 +3396,8 @@ void account_system_time(struct task_struct *p, int hardirq_offset,
         struct rq *rq = this_rq();
         cputime64_t tmp;
 
-        if (p->flags & PF_VCPU) {
-                account_guest_time(p, cputime);
-                return;
-        }
+        if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0))
+                return account_guest_time(p, cputime);
 
         p->stime = cputime_add(p->stime, cputime);
 
@@ -5278,23 +5282,9 @@ static void migrate_live_tasks(int src_cpu)
 }
 
 /*
- * activate_idle_task - move idle task to the _front_ of runqueue.
- */
-static void activate_idle_task(struct task_struct *p, struct rq *rq)
-{
-        update_rq_clock(rq);
-
-        if (p->state == TASK_UNINTERRUPTIBLE)
-                rq->nr_uninterruptible--;
-
-        enqueue_task(rq, p, 0);
-        inc_nr_running(p, rq);
-}
-
-/*
  * Schedules idle task to be the next runnable task on current CPU.
- * It does so by boosting its priority to highest possible and adding it to
- * the _front_ of the runqueue. Used by CPU offline code.
+ * It does so by boosting its priority to highest possible.
+ * Used by CPU offline code.
  */
 void sched_idle_next(void)
 {
@@ -5314,8 +5304,8 @@ void sched_idle_next(void)
 
         __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
 
-        /* Add idle task to the _front_ of its priority queue: */
-        activate_idle_task(p, rq);
+        update_rq_clock(rq);
+        activate_task(rq, p, 0);
 
         spin_unlock_irqrestore(&rq->lock, flags);
 }
@@ -7089,8 +7079,10 @@ void sched_move_task(struct task_struct *tsk)
 
         rq = task_rq_lock(tsk, &flags);
 
-        if (tsk->sched_class != &fair_sched_class)
+        if (tsk->sched_class != &fair_sched_class) {
+                set_task_cfs_rq(tsk, task_cpu(tsk));
                 goto done;
+        }
 
         update_rq_clock(rq);
 
@@ -7103,7 +7095,7 @@ void sched_move_task(struct task_struct *tsk)
                         tsk->sched_class->put_prev_task(rq, tsk);
         }
 
-        set_task_cfs_rq(tsk);
+        set_task_cfs_rq(tsk, task_cpu(tsk));
 
         if (on_rq) {
                 if (unlikely(running))
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index d3c03070872d..ee00da284b12 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -43,7 +43,7 @@ unsigned int sysctl_sched_min_granularity = 1000000ULL;
 /*
  * is kept at sysctl_sched_latency / sysctl_sched_min_granularity
  */
-unsigned int sched_nr_latency = 20;
+static unsigned int sched_nr_latency = 20;
 
 /*
  * After fork, child runs first. (default) If set to 0 then