* not in a quiescent state. There might be any number of tasks blocked
* while in an RCU read-side critical section.
*
- * Unlike the other rcu_*_qs() functions, callers to this function
- * must disable irqs in order to protect the assignment to
- * ->rcu_read_unlock_special.
- */
-static void rcu_preempt_qs(int cpu)
-{
- struct rcu_data *rdp = &per_cpu(rcu_preempt_data, cpu);
-
- if (rdp->passed_quiesce == 0)
- trace_rcu_grace_period(TPS("rcu_preempt"), rdp->gpnum, TPS("cpuqs"));
- rdp->passed_quiesce = 1;
- current->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS;
+ * As with the other rcu_*_qs() functions, callers to this function
+ * must disable preemption.
+ */
+static void rcu_preempt_qs(void)
+{
+ if (!__this_cpu_read(rcu_preempt_data.passed_quiesce)) {
+ trace_rcu_grace_period(TPS("rcu_preempt"),
+ __this_cpu_read(rcu_preempt_data.gpnum),
+ TPS("cpuqs"));
+ __this_cpu_write(rcu_preempt_data.passed_quiesce, 1);
+ barrier(); /* Coordinate with rcu_preempt_check_callbacks(). */
+ current->rcu_read_unlock_special.b.need_qs = false;
+ }
}
/*
struct rcu_node *rnp;
if (t->rcu_read_lock_nesting > 0 &&
- (t->rcu_read_unlock_special & RCU_READ_UNLOCK_BLOCKED) == 0) {
+ !t->rcu_read_unlock_special.b.blocked) {
/* Possibly blocking in an RCU read-side critical section. */
rdp = per_cpu_ptr(rcu_preempt_state.rda, cpu);
rnp = rdp->mynode;
raw_spin_lock_irqsave(&rnp->lock, flags);
smp_mb__after_unlock_lock();
- t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BLOCKED;
+ t->rcu_read_unlock_special.b.blocked = true;
t->rcu_blocked_node = rnp;
/*
: rnp->gpnum + 1);
raw_spin_unlock_irqrestore(&rnp->lock, flags);
} else if (t->rcu_read_lock_nesting < 0 &&
- t->rcu_read_unlock_special) {
+ t->rcu_read_unlock_special.s) {
/*
* Complete exit from RCU read-side critical section on
* grace period, then the fact that the task has been enqueued
* means that we continue to block the current grace period.
*/
- local_irq_save(flags);
- rcu_preempt_qs(cpu);
- local_irq_restore(flags);
+ rcu_preempt_qs();
}
/*
bool drop_boost_mutex = false;
#endif /* #ifdef CONFIG_RCU_BOOST */
struct rcu_node *rnp;
- int special;
+ union rcu_special special;
/* NMI handlers cannot block and cannot safely manipulate state. */
if (in_nmi())
/*
* If RCU core is waiting for this CPU to exit critical section,
- * let it know that we have done so.
+ * let it know that we have done so. Because irqs are disabled,
+ * t->rcu_read_unlock_special cannot change.
*/
special = t->rcu_read_unlock_special;
- if (special & RCU_READ_UNLOCK_NEED_QS) {
- rcu_preempt_qs(smp_processor_id());
- if (!t->rcu_read_unlock_special) {
+ if (special.b.need_qs) {
+ rcu_preempt_qs();
+ if (!t->rcu_read_unlock_special.s) {
local_irq_restore(flags);
return;
}
}
/* Clean up if blocked during RCU read-side critical section. */
- if (special & RCU_READ_UNLOCK_BLOCKED) {
- t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_BLOCKED;
+ if (special.b.blocked) {
+ t->rcu_read_unlock_special.b.blocked = false;
/*
* Remove this task from the list it blocked on. The
struct task_struct *t = current;
if (t->rcu_read_lock_nesting == 0) {
- rcu_preempt_qs(cpu);
+ rcu_preempt_qs();
return;
}
if (t->rcu_read_lock_nesting > 0 &&
- per_cpu(rcu_preempt_data, cpu).qs_pending)
- t->rcu_read_unlock_special |= RCU_READ_UNLOCK_NEED_QS;
+ per_cpu(rcu_preempt_data, cpu).qs_pending &&
+ !per_cpu(rcu_preempt_data, cpu).passed_quiesce)
+ t->rcu_read_unlock_special.b.need_qs = true;
}
#ifdef CONFIG_RCU_BOOST
return;
t->rcu_read_lock_nesting = 1;
barrier();
- t->rcu_read_unlock_special = RCU_READ_UNLOCK_BLOCKED;
+ t->rcu_read_unlock_special.b.blocked = true;
__rcu_read_unlock();
}
get_online_cpus();
for_each_online_cpu(cpu) {
smp_call_function_single(cpu, rcu_oom_notify_cpu, NULL, 1);
- cond_resched();
+ cond_resched_rcu_qs();
}
put_online_cpus();
if (!ACCESS_ONCE(rdp_leader->nocb_kthread))
return;
- if (!ACCESS_ONCE(rdp_leader->nocb_leader_wake) || force) {
+ if (ACCESS_ONCE(rdp_leader->nocb_leader_sleep) || force) {
/* Prior xchg orders against prior callback enqueue. */
- ACCESS_ONCE(rdp_leader->nocb_leader_wake) = true;
+ ACCESS_ONCE(rdp_leader->nocb_leader_sleep) = false;
wake_up(&rdp_leader->nocb_wq);
}
}
if (!rcu_nocb_poll) {
trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep");
wait_event_interruptible(my_rdp->nocb_wq,
- ACCESS_ONCE(my_rdp->nocb_leader_wake));
+ !ACCESS_ONCE(my_rdp->nocb_leader_sleep));
/* Memory barrier handled by smp_mb() calls below and repoll. */
} else if (firsttime) {
firsttime = false; /* Don't drown trace log with "Poll"! */
schedule_timeout_interruptible(1);
/* Rescan in case we were a victim of memory ordering. */
- my_rdp->nocb_leader_wake = false;
- smp_mb(); /* Ensure _wake false before scan. */
+ my_rdp->nocb_leader_sleep = true;
+ smp_mb(); /* Ensure _sleep true before scan. */
for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower)
if (ACCESS_ONCE(rdp->nocb_head)) {
/* Found CB, so short-circuit next wait. */
- my_rdp->nocb_leader_wake = true;
+ my_rdp->nocb_leader_sleep = false;
break;
}
goto wait_again;
rcu_nocb_wait_gp(my_rdp);
/*
- * We left ->nocb_leader_wake set to reduce cache thrashing.
- * We clear it now, but recheck for new callbacks while
+ * We left ->nocb_leader_sleep unset to reduce cache thrashing.
+ * We set it now, but recheck for new callbacks while
* traversing our follower list.
*/
- my_rdp->nocb_leader_wake = false;
- smp_mb(); /* Ensure _wake false before scan of ->nocb_head. */
+ my_rdp->nocb_leader_sleep = true;
+ smp_mb(); /* Ensure _sleep true before scan of ->nocb_head. */
/* Each pass through the following loop wakes a follower, if needed. */
for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) {
if (ACCESS_ONCE(rdp->nocb_head))
- my_rdp->nocb_leader_wake = true; /* No need to wait. */
+ my_rdp->nocb_leader_sleep = false;/* No need to sleep.*/
if (!rdp->nocb_gp_head)
continue; /* No CBs, so no need to wake follower. */
housekeeping_affine(current);
#endif /* #else #ifdef CONFIG_NO_HZ_FULL_SYSIDLE */
}
+
+/* Record the current task on dyntick-idle entry. */
+static void rcu_dynticks_task_enter(void)
+{
+#if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
+ ACCESS_ONCE(current->rcu_tasks_idle_cpu) = smp_processor_id();
+#endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */
+}
+
+/* Record no current task on dyntick-idle exit. */
+static void rcu_dynticks_task_exit(void)
+{
+#if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL)
+ ACCESS_ONCE(current->rcu_tasks_idle_cpu) = -1;
+#endif /* #if defined(CONFIG_TASKS_RCU) && defined(CONFIG_NO_HZ_FULL) */
+}
projects / cascardo / linux.git / blobdiff