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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2011-05-19 15:08:58 +0900
committerIngo Molnar <mingo@elte.hu>2011-05-28 17:02:57 +0200
commit1e1b6c511d1b23cb7c3b619d82fc7bd9f620565d (patch)
treec50e88412c8b42264177dc125f74a30f9c7a82d9 /kernel
parent1e876231785d82443a5ac8b6c660e9f51bc5dede (diff)
downloadlinux-1e1b6c511d1b23cb7c3b619d82fc7bd9f620565d.tar.gz
cpuset: Fix cpuset_cpus_allowed_fallback(), don't update tsk->rt.nr_cpus_allowed
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>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/cpuset.c4
-rw-r--r--kernel/kthread.c4
-rw-r--r--kernel/sched.c19
3 files changed, 16 insertions, 11 deletions
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 1ceeb049c827..9c9b7545c810 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -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);
 	}
 
diff --git a/kernel/kthread.c b/kernel/kthread.c
index 3b34d2732bce..4ba7cccb4994 100644
--- a/kernel/kthread.c
+++ b/kernel/kthread.c
@@ -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);
diff --git a/kernel/sched.c b/kernel/sched.c
index a80ee911900e..cbb3a0eee58e 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -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))