[git pull] scheduler fixes

Ingo Molnar
2007-11-15T20:09:21Z

Linus, please pull the latest scheduler git tree from:

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

it includes 3 fixes and 3 cleanups. Build and boot tested on 64-bit and
32-bit x86. Thanks,

Ingo

------------------>
Adrian Bunk (1):
sched: make sched_nr_latency static

Christian Borntraeger (1):
sched: fix accounting of interrupts during guest execution on s390

Dmitry Adamushko (2):
sched: fix __set_task_cpu() SMP race
sched: remove activate_idle_task()

Ingo Molnar (1):
sched: reorder SCHED_FEAT_ bits

Oleg Nesterov (1):
sched: fix SCHED_FIFO tasks & FAIR_GROUP_SCHED

sched.c | 62 +++++++++++++++++++++++++----------------------------------
sched_fair.c | 2 -
2 files changed, 28 insertions(+), 36 deletions(-)

Index: linux/kernel/sched.c
===================================================================
--- linux.orig/kernel/sched.c
+++ linux/kernel/sched.c
@@ -216,15 +216,15 @@ static inline struct task_group *task_gr
}

/* 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 *r
*/
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

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_str
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_c
}

/*
- * 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

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->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))
Index: linux/kernel/sched_fair.c
===================================================================
--- linux.orig/kernel/sched_fair.c
+++ linux/kernel/sched_fair.c
@@ -43,7 +43,7 @@ unsigned int sysctl_sched_min_granularit
/*
* 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