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cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed

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The rule is, we have to update tsk->rt.nr_cpus_allowed if we change
tsk->cpus_allowed. Otherwise RT scheduler may confuse.

Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/4DD4B3FA.5060901@jp.fujitsu.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
KOSAKI Motohiro 2011-05-19 15:08:58 +09:00 committed by Ingo Molnar
parent 1e87623178
commit 1e1b6c511d
5 changed files with 24 additions and 12 deletions
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2
include/linux/cpuset.h
View File

@ -146,7 +146,7 @@ static inline void cpuset_cpus_allowed(struct task_struct *p,
static inline int cpuset_cpus_allowed_fallback(struct task_struct *p)
{
cpumask_copy(&p->cpus_allowed, cpu_possible_mask);
do_set_cpus_allowed(p, cpu_possible_mask);
return cpumask_any(cpu_active_mask);
}

7
include/linux/sched.h
View File

@ -1841,9 +1841,16 @@ static inline void rcu_copy_process(struct task_struct *p)
#endif
#ifdef CONFIG_SMP
extern void do_set_cpus_allowed(struct task_struct *p,
const struct cpumask *new_mask);
extern int set_cpus_allowed_ptr(struct task_struct *p,
const struct cpumask *new_mask);
#else
static inline void do_set_cpus_allowed(struct task_struct *p,
const struct cpumask *new_mask)
{
}
static inline int set_cpus_allowed_ptr(struct task_struct *p,
const struct cpumask *new_mask)
{

4
kernel/cpuset.c
View File

@ -2190,7 +2190,7 @@ int cpuset_cpus_allowed_fallback(struct task_struct *tsk)
rcu_read_lock();
cs = task_cs(tsk);
if (cs)
cpumask_copy(&tsk->cpus_allowed, cs->cpus_allowed);
do_set_cpus_allowed(tsk, cs->cpus_allowed);
rcu_read_unlock();
/*
@ -2217,7 +2217,7 @@ int cpuset_cpus_allowed_fallback(struct task_struct *tsk)
* Like above we can temporary set any mask and rely on
* set_cpus_allowed_ptr() as synchronization point.
*/
cpumask_copy(&tsk->cpus_allowed, cpu_possible_mask);
do_set_cpus_allowed(tsk, cpu_possible_mask);
cpu = cpumask_any(cpu_active_mask);
}

4
kernel/kthread.c
View File

@ -202,8 +202,8 @@ void kthread_bind(struct task_struct *p, unsigned int cpu)
return;
}
p->cpus_allowed = cpumask_of_cpu(cpu);
p->rt.nr_cpus_allowed = 1;
/* It's safe because the task is inactive. */
do_set_cpus_allowed(p, cpumask_of(cpu));
p->flags |= PF_THREAD_BOUND;
}
EXPORT_SYMBOL(kthread_bind);

19
kernel/sched.c
View File

@ -5860,7 +5860,7 @@ void __cpuinit init_idle(struct task_struct *idle, int cpu)
idle->state = TASK_RUNNING;
idle->se.exec_start = sched_clock();
cpumask_copy(&idle->cpus_allowed, cpumask_of(cpu));
do_set_cpus_allowed(idle, cpumask_of(cpu));
/*
* We're having a chicken and egg problem, even though we are
* holding rq->lock, the cpu isn't yet set to this cpu so the
@ -5948,6 +5948,16 @@ static inline void sched_init_granularity(void)
}
#ifdef CONFIG_SMP
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
if (p->sched_class && p->sched_class->set_cpus_allowed)
p->sched_class->set_cpus_allowed(p, new_mask);
else {
cpumask_copy(&p->cpus_allowed, new_mask);
p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
}
}
/*
* This is how migration works:
*
@ -5993,12 +6003,7 @@ int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
goto out;
}
if (p->sched_class->set_cpus_allowed)
p->sched_class->set_cpus_allowed(p, new_mask);
else {
cpumask_copy(&p->cpus_allowed, new_mask);
p->rt.nr_cpus_allowed = cpumask_weight(new_mask);
}
do_set_cpus_allowed(p, new_mask);
/* Can the task run on the task's current CPU? If so, we're done */
if (cpumask_test_cpu(task_cpu(p), new_mask))