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-rw-r--r--kernel/rcutree.c15
-rw-r--r--kernel/sched/core.c10
2 files changed, 16 insertions, 9 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 32618b3fe4e6..1dc9f3604ad8 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -898,6 +898,12 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
force_quiescent_state(rsp); /* Kick them all. */
}
+/*
+ * This function really isn't for public consumption, but RCU is special in
+ * that context switches can allow the state machine to make progress.
+ */
+extern void resched_cpu(int cpu);
+
static void print_cpu_stall(struct rcu_state *rsp)
{
int cpu;
@@ -927,7 +933,14 @@ static void print_cpu_stall(struct rcu_state *rsp)
3 * rcu_jiffies_till_stall_check() + 3;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
- set_need_resched(); /* kick ourselves to get things going. */
+ /*
+ * Attempt to revive the RCU machinery by forcing a context switch.
+ *
+ * A context switch would normally allow the RCU state machine to make
+ * progress and it could be we're stuck in kernel space without context
+ * switches for an entirely unreasonable amount of time.
+ */
+ resched_cpu(smp_processor_id());
}
static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ac5796783c49..242da0c03aba 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -513,12 +513,11 @@ static inline void init_hrtick(void)
* might also involve a cross-CPU call to trigger the scheduler on
* the target CPU.
*/
-#ifdef CONFIG_SMP
void resched_task(struct task_struct *p)
{
int cpu;
- assert_raw_spin_locked(&task_rq(p)->lock);
+ lockdep_assert_held(&task_rq(p)->lock);
if (test_tsk_need_resched(p))
return;
@@ -546,6 +545,7 @@ void resched_cpu(int cpu)
raw_spin_unlock_irqrestore(&rq->lock, flags);
}
+#ifdef CONFIG_SMP
#ifdef CONFIG_NO_HZ_COMMON
/*
* In the semi idle case, use the nearest busy cpu for migrating timers
@@ -693,12 +693,6 @@ void sched_avg_update(struct rq *rq)
}
}
-#else /* !CONFIG_SMP */
-void resched_task(struct task_struct *p)
-{
- assert_raw_spin_locked(&task_rq(p)->lock);
- set_tsk_need_resched(p);
-}
#endif /* CONFIG_SMP */
#if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \