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Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/…
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…linux/kernel/git/tip/linux-2.6-tip

* 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched, delay accounting: fix incorrect delay time when constantly waiting on runqueue
  sched: CPU hotplug events must not destroy scheduler domains created by the cpusets
  sched: rt-group: fix RR buglet
  sched: rt-group: heirarchy aware throttle
  sched: rt-group: fix hierarchy
  sched: NULL pointer dereference while setting sched_rt_period_us
  sched: fix defined-but-unused warning
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@torvalds
torvalds committed Jun 20, 2008
2 parents b1ae8d3 + d4abc23 commit e570dc2
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Showing 4 changed files with 73 additions and 29 deletions.
6 changes: 6 additions & 0 deletions kernel/cpuset.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1890,6 +1890,12 @@ static void common_cpu_mem_hotplug_unplug(void)
top_cpuset.mems_allowed = node_states[N_HIGH_MEMORY];
scan_for_empty_cpusets(&top_cpuset);

/*
* Scheduler destroys domains on hotplug events.
* Rebuild them based on the current settings.
*/
rebuild_sched_domains();

cgroup_unlock();
}

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27 changes: 25 additions & 2 deletions kernel/sched.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1127,6 +1127,7 @@ static enum hrtimer_restart hrtick(struct hrtimer *timer)
return HRTIMER_NORESTART;
}

#ifdef CONFIG_SMP
static void hotplug_hrtick_disable(int cpu)
{
struct rq *rq = cpu_rq(cpu);
Expand Down Expand Up @@ -1182,6 +1183,7 @@ static void init_hrtick(void)
{
hotcpu_notifier(hotplug_hrtick, 0);
}
#endif /* CONFIG_SMP */

static void init_rq_hrtick(struct rq *rq)
{
Expand Down Expand Up @@ -7235,6 +7237,18 @@ void __attribute__((weak)) arch_update_cpu_topology(void)
{
}

/*
* Free current domain masks.
* Called after all cpus are attached to NULL domain.
*/
static void free_sched_domains(void)
{
ndoms_cur = 0;
if (doms_cur != &fallback_doms)
kfree(doms_cur);
doms_cur = &fallback_doms;
}

/*
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
* For now this just excludes isolated cpus, but could be used to
Expand Down Expand Up @@ -7382,6 +7396,7 @@ int arch_reinit_sched_domains(void)
get_online_cpus();
mutex_lock(&sched_domains_mutex);
detach_destroy_domains(&cpu_online_map);
free_sched_domains();
err = arch_init_sched_domains(&cpu_online_map);
mutex_unlock(&sched_domains_mutex);
put_online_cpus();
Expand Down Expand Up @@ -7467,6 +7482,7 @@ static int update_sched_domains(struct notifier_block *nfb,
case CPU_DOWN_PREPARE:
case CPU_DOWN_PREPARE_FROZEN:
detach_destroy_domains(&cpu_online_map);
free_sched_domains();
return NOTIFY_OK;

case CPU_UP_CANCELED:
Expand All @@ -7485,8 +7501,16 @@ static int update_sched_domains(struct notifier_block *nfb,
return NOTIFY_DONE;
}

#ifndef CONFIG_CPUSETS
/*
* Create default domain partitioning if cpusets are disabled.
* Otherwise we let cpusets rebuild the domains based on the
* current setup.
*/

/* The hotplug lock is already held by cpu_up/cpu_down */
arch_init_sched_domains(&cpu_online_map);
#endif

return NOTIFY_OK;
}
Expand Down Expand Up @@ -7626,7 +7650,6 @@ static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
else
rt_se->rt_rq = parent->my_q;

rt_se->rt_rq = &rq->rt;
rt_se->my_q = rt_rq;
rt_se->parent = parent;
INIT_LIST_HEAD(&rt_se->run_list);
Expand Down Expand Up @@ -8348,7 +8371,7 @@ static unsigned long to_ratio(u64 period, u64 runtime)
#ifdef CONFIG_CGROUP_SCHED
static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
{
struct task_group *tgi, *parent = tg->parent;
struct task_group *tgi, *parent = tg ? tg->parent : NULL;
unsigned long total = 0;

if (!parent) {
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63 changes: 36 additions & 27 deletions kernel/sched_rt.c
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Original file line number Diff line number Diff line change
Expand Up @@ -449,13 +449,19 @@ void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
#endif
}

static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
struct rt_prio_array *array = &rt_rq->active;
struct rt_rq *group_rq = group_rt_rq(rt_se);

if (group_rq && rt_rq_throttled(group_rq))
/*
* Don't enqueue the group if its throttled, or when empty.
* The latter is a consequence of the former when a child group
* get throttled and the current group doesn't have any other
* active members.
*/
if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running))
return;

list_add_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
Expand All @@ -464,7 +470,7 @@ static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
inc_rt_tasks(rt_se, rt_rq);
}

static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
static void __dequeue_rt_entity(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
struct rt_prio_array *array = &rt_rq->active;
Expand All @@ -480,19 +486,37 @@ static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
* Because the prio of an upper entry depends on the lower
* entries, we must remove entries top - down.
*/
static void dequeue_rt_stack(struct task_struct *p)
static void dequeue_rt_stack(struct sched_rt_entity *rt_se)
{
struct sched_rt_entity *rt_se, *back = NULL;
struct sched_rt_entity *back = NULL;

rt_se = &p->rt;
for_each_sched_rt_entity(rt_se) {
rt_se->back = back;
back = rt_se;
}

for (rt_se = back; rt_se; rt_se = rt_se->back) {
if (on_rt_rq(rt_se))
dequeue_rt_entity(rt_se);
__dequeue_rt_entity(rt_se);
}
}

static void enqueue_rt_entity(struct sched_rt_entity *rt_se)
{
dequeue_rt_stack(rt_se);
for_each_sched_rt_entity(rt_se)
__enqueue_rt_entity(rt_se);
}

static void dequeue_rt_entity(struct sched_rt_entity *rt_se)
{
dequeue_rt_stack(rt_se);

for_each_sched_rt_entity(rt_se) {
struct rt_rq *rt_rq = group_rt_rq(rt_se);

if (rt_rq && rt_rq->rt_nr_running)
__enqueue_rt_entity(rt_se);
}
}

Expand All @@ -506,32 +530,15 @@ static void enqueue_task_rt(struct rq *rq, struct task_struct *p, int wakeup)
if (wakeup)
rt_se->timeout = 0;

dequeue_rt_stack(p);

/*
* enqueue everybody, bottom - up.
*/
for_each_sched_rt_entity(rt_se)
enqueue_rt_entity(rt_se);
enqueue_rt_entity(rt_se);
}

static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int sleep)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq;

update_curr_rt(rq);

dequeue_rt_stack(p);

/*
* re-enqueue all non-empty rt_rq entities.
*/
for_each_sched_rt_entity(rt_se) {
rt_rq = group_rt_rq(rt_se);
if (rt_rq && rt_rq->rt_nr_running)
enqueue_rt_entity(rt_se);
}
dequeue_rt_entity(rt_se);
}

/*
Expand All @@ -542,8 +549,10 @@ static
void requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
struct rt_prio_array *array = &rt_rq->active;
struct list_head *queue = array->queue + rt_se_prio(rt_se);

list_move_tail(&rt_se->run_list, array->queue + rt_se_prio(rt_se));
if (on_rt_rq(rt_se))
list_move_tail(&rt_se->run_list, queue);
}

static void requeue_task_rt(struct rq *rq, struct task_struct *p)
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6 changes: 6 additions & 0 deletions kernel/sched_stats.h
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Original file line number Diff line number Diff line change
Expand Up @@ -198,6 +198,9 @@ static inline void sched_info_queued(struct task_struct *t)
/*
* Called when a process ceases being the active-running process, either
* voluntarily or involuntarily. Now we can calculate how long we ran.
* Also, if the process is still in the TASK_RUNNING state, call
* sched_info_queued() to mark that it has now again started waiting on
* the runqueue.
*/
static inline void sched_info_depart(struct task_struct *t)
{
Expand All @@ -206,6 +209,9 @@ static inline void sched_info_depart(struct task_struct *t)

t->sched_info.cpu_time += delta;
rq_sched_info_depart(task_rq(t), delta);

if (t->state == TASK_RUNNING)
sched_info_queued(t);
}

/*
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