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authorIngo Molnar <mingo@elte.hu>2010-05-07 11:30:29 +0200
committerIngo Molnar <mingo@elte.hu>2010-05-07 11:30:30 +0200
commitcce913178118b0b36742eb7544c2b38a0c957ee7 (patch)
tree25a6d7b4e01fea2932e6e2962a75f7a3d8c19a4f /kernel/sched.c
parentd9f599e1e6d019968b35d2dc63074b9e8964fa69 (diff)
parent4fd38e4595e2f6c9d27732c042a0e16b2753049c (diff)
Merge branch 'perf/urgent' into perf/core
Merge reason: Resolve patch dependency Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c18
1 files changed, 14 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index b0bbadc2495..b11b80a3eed 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -323,6 +323,15 @@ 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_rq(struct task_struct *p, unsigned int cpu)
{
+ /*
+ * Strictly speaking this rcu_read_lock() is not needed since the
+ * task_group is tied to the cgroup, which in turn can never go away
+ * as long as there are tasks attached to it.
+ *
+ * However since task_group() uses task_subsys_state() which is an
+ * rcu_dereference() user, this quiets CONFIG_PROVE_RCU.
+ */
+ rcu_read_lock();
#ifdef CONFIG_FAIR_GROUP_SCHED
p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
p->se.parent = task_group(p)->se[cpu];
@@ -332,6 +341,7 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
p->rt.rt_rq = task_group(p)->rt_rq[cpu];
p->rt.parent = task_group(p)->rt_se[cpu];
#endif
+ rcu_read_unlock();
}
#else
@@ -3737,7 +3747,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
* the mutex owner just released it and exited.
*/
if (probe_kernel_address(&owner->cpu, cpu))
- goto out;
+ return 0;
#else
cpu = owner->cpu;
#endif
@@ -3747,14 +3757,14 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
* the cpu field may no longer be valid.
*/
if (cpu >= nr_cpumask_bits)
- goto out;
+ return 0;
/*
* We need to validate that we can do a
* get_cpu() and that we have the percpu area.
*/
if (!cpu_online(cpu))
- goto out;
+ return 0;
rq = cpu_rq(cpu);
@@ -3773,7 +3783,7 @@ int mutex_spin_on_owner(struct mutex *lock, struct thread_info *owner)
cpu_relax();
}
-out:
+
return 1;
}
#endif