1 files changed, 29 insertions, 131 deletions

diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 6e2ef4b2b920..e8e67dac6f3e 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -24,12 +24,6 @@
  *	   Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  */
 
-#include <linux/delay.h>
-#include <linux/gfp.h>
-#include <linux/oom.h>
-#include <linux/smpboot.h>
-#include "../time/tick-internal.h"
-
 #define RCU_KTHREAD_PRIO 1
 
 #ifdef CONFIG_RCU_BOOST
@@ -370,7 +364,7 @@ void rcu_read_unlock_special(struct task_struct *t)
 	}
 
 	/* Hardware IRQ handlers cannot block, complain if they get here. */
-	if (WARN_ON_ONCE(in_irq() || in_serving_softirq())) {
+	if (WARN_ON_ONCE(preempt_count() & (HARDIRQ_MASK | SOFTIRQ_OFFSET))) {
 		local_irq_restore(flags);
 		return;
 	}
@@ -670,15 +664,6 @@ static void rcu_preempt_check_callbacks(int cpu)
 		t->rcu_read_unlock_special |= RCU_READ_UNLOCK_NEED_QS;
 }
 
-#ifdef CONFIG_RCU_BOOST
-
-static void rcu_preempt_do_callbacks(void)
-{
-	rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data));
-}
-
-#endif /* #ifdef CONFIG_RCU_BOOST */
-
 /*
  * Queue a preemptible-RCU callback for invocation after a grace period.
  */
@@ -1146,6 +1131,19 @@ void exit_rcu(void)
 
 #endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
 
+/*
+ * If boosting, set rcuc kthreads to realtime priority.
+ */
+static void rcu_cpu_kthread_setup(unsigned int cpu)
+{
+#ifdef CONFIG_RCU_BOOST
+	struct sched_param sp;
+
+	sp.sched_priority = RCU_KTHREAD_PRIO;
+	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
+#endif /* #ifdef CONFIG_RCU_BOOST */
+}
+
 #ifdef CONFIG_RCU_BOOST
 
 #include "../locking/rtmutex_common.h"
@@ -1177,16 +1175,6 @@ static void rcu_initiate_boost_trace(struct rcu_node *rnp)
 
 #endif /* #else #ifdef CONFIG_RCU_TRACE */
 
-static void rcu_wake_cond(struct task_struct *t, int status)
-{
-	/*
-	 * If the thread is yielding, only wake it when this
-	 * is invoked from idle
-	 */
-	if (status != RCU_KTHREAD_YIELDING || is_idle_task(current))
-		wake_up_process(t);
-}
-
 /*
  * Carry out RCU priority boosting on the task indicated by ->exp_tasks
  * or ->boost_tasks, advancing the pointer to the next task in the
@@ -1331,23 +1319,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
 }
 
 /*
- * Wake up the per-CPU kthread to invoke RCU callbacks.
- */
-static void invoke_rcu_callbacks_kthread(void)
-{
-	unsigned long flags;
-
-	local_irq_save(flags);
-	__this_cpu_write(rcu_cpu_has_work, 1);
-	if (__this_cpu_read(rcu_cpu_kthread_task) != NULL &&
-	    current != __this_cpu_read(rcu_cpu_kthread_task)) {
-		rcu_wake_cond(__this_cpu_read(rcu_cpu_kthread_task),
-			      __this_cpu_read(rcu_cpu_kthread_status));
-	}
-	local_irq_restore(flags);
-}
-
-/*
  * Is the current CPU running the RCU-callbacks kthread?
  * Caller must have preemption disabled.
  */
@@ -1402,67 +1373,6 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
 	return 0;
 }
 
-static void rcu_kthread_do_work(void)
-{
-	rcu_do_batch(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data));
-	rcu_do_batch(&rcu_bh_state, this_cpu_ptr(&rcu_bh_data));
-	rcu_preempt_do_callbacks();
-}
-
-static void rcu_cpu_kthread_setup(unsigned int cpu)
-{
-	struct sched_param sp;
-
-	sp.sched_priority = RCU_KTHREAD_PRIO;
-	sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
-}
-
-static void rcu_cpu_kthread_park(unsigned int cpu)
-{
-	per_cpu(rcu_cpu_kthread_status, cpu) = RCU_KTHREAD_OFFCPU;
-}
-
-static int rcu_cpu_kthread_should_run(unsigned int cpu)
-{
-	return __this_cpu_read(rcu_cpu_has_work);
-}
-
-/*
- * Per-CPU kernel thread that invokes RCU callbacks.  This replaces the
- * RCU softirq used in flavors and configurations of RCU that do not
- * support RCU priority boosting.
- */
-static void rcu_cpu_kthread(unsigned int cpu)
-{
-	unsigned int *statusp = this_cpu_ptr(&rcu_cpu_kthread_status);
-	char work, *workp = this_cpu_ptr(&rcu_cpu_has_work);
-	int spincnt;
-
-	for (spincnt = 0; spincnt < 10; spincnt++) {
-		trace_rcu_utilization(TPS("Start CPU kthread@rcu_wait"));
-		local_bh_disable();
-		*statusp = RCU_KTHREAD_RUNNING;
-		this_cpu_inc(rcu_cpu_kthread_loops);
-		local_irq_disable();
-		work = *workp;
-		*workp = 0;
-		local_irq_enable();
-		if (work)
-			rcu_kthread_do_work();
-		local_bh_enable();
-		if (*workp == 0) {
-			trace_rcu_utilization(TPS("End CPU kthread@rcu_wait"));
-			*statusp = RCU_KTHREAD_WAITING;
-			return;
-		}
-	}
-	*statusp = RCU_KTHREAD_YIELDING;
-	trace_rcu_utilization(TPS("Start CPU kthread@rcu_yield"));
-	schedule_timeout_interruptible(2);
-	trace_rcu_utilization(TPS("End CPU kthread@rcu_yield"));
-	*statusp = RCU_KTHREAD_WAITING;
-}
-
 /*
  * Set the per-rcu_node kthread's affinity to cover all CPUs that are
  * served by the rcu_node in question.  The CPU hotplug lock is still
@@ -1496,27 +1406,14 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
 	free_cpumask_var(cm);
 }
 
-static struct smp_hotplug_thread rcu_cpu_thread_spec = {
-	.store			= &rcu_cpu_kthread_task,
-	.thread_should_run	= rcu_cpu_kthread_should_run,
-	.thread_fn		= rcu_cpu_kthread,
-	.thread_comm		= "rcuc/%u",
-	.setup			= rcu_cpu_kthread_setup,
-	.park			= rcu_cpu_kthread_park,
-};
-
 /*
  * Spawn all kthreads -- called as soon as the scheduler is running.
  */
 static int __init rcu_spawn_kthreads(void)
 {
 	struct rcu_node *rnp;
-	int cpu;
 
 	rcu_scheduler_fully_active = 1;
-	for_each_possible_cpu(cpu)
-		per_cpu(rcu_cpu_has_work, cpu) = 0;
-	BUG_ON(smpboot_register_percpu_thread(&rcu_cpu_thread_spec));
 	rnp = rcu_get_root(rcu_state);
 	(void)rcu_spawn_one_boost_kthread(rcu_state, rnp);
 	if (NUM_RCU_NODES > 1) {
@@ -1544,11 +1441,6 @@ static void rcu_initiate_boost(struct rcu_node *rnp, unsigned long flags)
 	raw_spin_unlock_irqrestore(&rnp->lock, flags);
 }
 
-static void invoke_rcu_callbacks_kthread(void)
-{
-	WARN_ON_ONCE(1);
-}
-
 static bool rcu_is_callbacks_kthread(void)
 {
 	return false;
@@ -1575,7 +1467,7 @@ static void rcu_prepare_kthreads(int cpu)
 
 #endif /* #else #ifdef CONFIG_RCU_BOOST */
 
-#if !defined(CONFIG_RCU_FAST_NO_HZ)
+#if !defined(CONFIG_RCU_FAST_NO_HZ) || defined(CONFIG_PREEMPT_RT_FULL)
 
 /*
  * Check to see if any future RCU-related work will need to be done
@@ -1591,6 +1483,9 @@ int rcu_needs_cpu(int cpu, unsigned long *delta_jiffies)
 	*delta_jiffies = ULONG_MAX;
 	return rcu_cpu_has_callbacks(cpu, NULL);
 }
+#endif	/* !defined(CONFIG_RCU_FAST_NO_HZ) || defined(CONFIG_PREEMPT_RT_FULL) */
+
+#if !defined(CONFIG_RCU_FAST_NO_HZ)
 
 /*
  * Because we do not have RCU_FAST_NO_HZ, don't bother cleaning up
@@ -1688,6 +1583,8 @@ static bool rcu_try_advance_all_cbs(void)
 	return cbs_ready;
 }
 
+#ifndef CONFIG_PREEMPT_RT_FULL
+
 /*
  * Allow the CPU to enter dyntick-idle mode unless it has callbacks ready
  * to invoke.  If the CPU has callbacks, try to advance them.  Tell the
@@ -1726,6 +1623,7 @@ int rcu_needs_cpu(int cpu, unsigned long *dj)
 	}
 	return 0;
 }
+#endif	/* #ifndef CONFIG_PREEMPT_RT_FULL */
 
 /*
  * Prepare a CPU for idle from an RCU perspective.  The first major task
@@ -2079,7 +1977,7 @@ static int rcu_nocb_needs_gp(struct rcu_state *rsp)
  */
 static void rcu_nocb_gp_cleanup(struct rcu_state *rsp, struct rcu_node *rnp)
 {
-	wake_up_all(&rnp->nocb_gp_wq[rnp->completed & 0x1]);
+	swait_wake_all(&rnp->nocb_gp_wq[rnp->completed & 0x1]);
 }
 
 /*
@@ -2097,8 +1995,8 @@ static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq)
 
 static void rcu_init_one_nocb(struct rcu_node *rnp)
 {
-	init_waitqueue_head(&rnp->nocb_gp_wq[0]);
-	init_waitqueue_head(&rnp->nocb_gp_wq[1]);
+	init_swait_head(&rnp->nocb_gp_wq[0]);
+	init_swait_head(&rnp->nocb_gp_wq[1]);
 }
 
 /* Is the specified CPU a no-CPUs CPU? */
@@ -2143,7 +2041,7 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp,
 	len = atomic_long_read(&rdp->nocb_q_count);
 	if (old_rhpp == &rdp->nocb_head) {
 		if (!irqs_disabled_flags(flags)) {
-			wake_up(&rdp->nocb_wq); /* ... if queue was empty ... */
+			swait_wake(&rdp->nocb_wq); /* ... if queue was empty ... */
 			trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
 					    TPS("WakeEmpty"));
 		} else {
@@ -2247,7 +2145,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
 	 */
 	trace_rcu_future_gp(rnp, rdp, c, TPS("StartWait"));
 	for (;;) {
-		wait_event_interruptible(
+		swait_event_interruptible(
 			rnp->nocb_gp_wq[c & 0x1],
 			(d = ULONG_CMP_GE(ACCESS_ONCE(rnp->completed), c)));
 		if (likely(d))
@@ -2278,7 +2176,7 @@ static int rcu_nocb_kthread(void *arg)
 		if (!rcu_nocb_poll) {
 			trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
 					    TPS("Sleep"));
-			wait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);
+			swait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);
 			/* Memory barrier provide by xchg() below. */
 		} else if (firsttime) {
 			firsttime = 0;
@@ -2352,7 +2250,7 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp)
 	if (!rcu_nocb_need_deferred_wakeup(rdp))
 		return;
 	ACCESS_ONCE(rdp->nocb_defer_wakeup) = false;
-	wake_up(&rdp->nocb_wq);
+	swait_wake(&rdp->nocb_wq);
 	trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("DeferredWakeEmpty"));
 }
 
@@ -2360,7 +2258,7 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp)
 static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
 {
 	rdp->nocb_tail = &rdp->nocb_head;
-	init_waitqueue_head(&rdp->nocb_wq);
+	init_swait_head(&rdp->nocb_wq);
 }
 
 /* Create a kthread for each RCU flavor for each no-CBs CPU. */