static struct lock_class_key rcu_node_class[RCU_NUM_LVLS];
static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS];
static struct lock_class_key rcu_exp_class[RCU_NUM_LVLS];
+static struct lock_class_key rcu_exp_sched_class[RCU_NUM_LVLS];
/*
* In order to export the rcu_state name to the tracing tools, it
* It is illegal to enter an extended quiescent state while
* in an RCU read-side critical section.
*/
- rcu_lockdep_assert(!lock_is_held(&rcu_lock_map),
- "Illegal idle entry in RCU read-side critical section.");
- rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map),
- "Illegal idle entry in RCU-bh read-side critical section.");
- rcu_lockdep_assert(!lock_is_held(&rcu_sched_lock_map),
- "Illegal idle entry in RCU-sched read-side critical section.");
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_lock_map),
+ "Illegal idle entry in RCU read-side critical section.");
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map),
+ "Illegal idle entry in RCU-bh read-side critical section.");
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_sched_lock_map),
+ "Illegal idle entry in RCU-sched read-side critical section.");
}
/*
}
EXPORT_SYMBOL_GPL(rcu_idle_enter);
-#ifdef CONFIG_RCU_USER_QS
+#ifdef CONFIG_NO_HZ_FULL
/**
* rcu_user_enter - inform RCU that we are resuming userspace.
*
{
rcu_eqs_enter(1);
}
-#endif /* CONFIG_RCU_USER_QS */
+#endif /* CONFIG_NO_HZ_FULL */
/**
* rcu_irq_exit - inform RCU that current CPU is exiting irq towards idle
}
EXPORT_SYMBOL_GPL(rcu_idle_exit);
-#ifdef CONFIG_RCU_USER_QS
+#ifdef CONFIG_NO_HZ_FULL
/**
* rcu_user_exit - inform RCU that we are exiting userspace.
*
{
rcu_eqs_exit(1);
}
-#endif /* CONFIG_RCU_USER_QS */
+#endif /* CONFIG_NO_HZ_FULL */
/**
* rcu_irq_enter - inform RCU that current CPU is entering irq away from idle
{
bool ret;
- preempt_disable();
+ preempt_disable_notrace();
ret = __rcu_is_watching();
- preempt_enable();
+ preempt_enable_notrace();
return ret;
}
EXPORT_SYMBOL_GPL(rcu_is_watching);
rsp->gp_state = RCU_GP_WAIT_FQS;
ret = wait_event_interruptible_timeout(rsp->gp_wq,
rcu_gp_fqs_check_wake(rsp, &gf), j);
- rsp->gp_state = RCU_GP_DONE_FQS;
+ rsp->gp_state = RCU_GP_DOING_FQS;
/* Locking provides needed memory barriers. */
/* If grace period done, leave loop. */
if (!READ_ONCE(rnp->qsmask) &&
*/
void synchronize_sched(void)
{
- rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
- !lock_is_held(&rcu_lock_map) &&
- !lock_is_held(&rcu_sched_lock_map),
- "Illegal synchronize_sched() in RCU-sched read-side critical section");
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map),
+ "Illegal synchronize_sched() in RCU-sched read-side critical section");
if (rcu_blocking_is_gp())
return;
if (rcu_gp_is_expedited())
*/
void synchronize_rcu_bh(void)
{
- rcu_lockdep_assert(!lock_is_held(&rcu_bh_lock_map) &&
- !lock_is_held(&rcu_lock_map) &&
- !lock_is_held(&rcu_sched_lock_map),
- "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section");
+ RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
+ lock_is_held(&rcu_lock_map) ||
+ lock_is_held(&rcu_sched_lock_map),
+ "Illegal synchronize_rcu_bh() in RCU-bh read-side critical section");
if (rcu_blocking_is_gp())
return;
if (rcu_gp_is_expedited())
}
EXPORT_SYMBOL_GPL(cond_synchronize_rcu);
+/**
+ * get_state_synchronize_sched - Snapshot current RCU-sched state
+ *
+ * Returns a cookie that is used by a later call to cond_synchronize_sched()
+ * to determine whether or not a full grace period has elapsed in the
+ * meantime.
+ */
+unsigned long get_state_synchronize_sched(void)
+{
+ /*
+ * Any prior manipulation of RCU-protected data must happen
+ * before the load from ->gpnum.
+ */
+ smp_mb(); /* ^^^ */
+
+ /*
+ * Make sure this load happens before the purportedly
+ * time-consuming work between get_state_synchronize_sched()
+ * and cond_synchronize_sched().
+ */
+ return smp_load_acquire(&rcu_sched_state.gpnum);
+}
+EXPORT_SYMBOL_GPL(get_state_synchronize_sched);
+
+/**
+ * cond_synchronize_sched - Conditionally wait for an RCU-sched grace period
+ *
+ * @oldstate: return value from earlier call to get_state_synchronize_sched()
+ *
+ * If a full RCU-sched grace period has elapsed since the earlier call to
+ * get_state_synchronize_sched(), just return. Otherwise, invoke
+ * synchronize_sched() to wait for a full grace period.
+ *
+ * Yes, this function does not take counter wrap into account. But
+ * counter wrap is harmless. If the counter wraps, we have waited for
+ * more than 2 billion grace periods (and way more on a 64-bit system!),
+ * so waiting for one additional grace period should be just fine.
+ */
+void cond_synchronize_sched(unsigned long oldstate)
+{
+ unsigned long newstate;
+
+ /*
+ * Ensure that this load happens before any RCU-destructive
+ * actions the caller might carry out after we return.
+ */
+ newstate = smp_load_acquire(&rcu_sched_state.completed);
+ if (ULONG_CMP_GE(oldstate, newstate))
+ synchronize_sched();
+}
+EXPORT_SYMBOL_GPL(cond_synchronize_sched);
+
/* Adjust sequence number for start of update-side operation. */
static void rcu_seq_start(unsigned long *sp)
{
struct rcu_node *rnp0;
struct rcu_node *rnp1 = NULL;
+ /*
+ * First try directly acquiring the root lock in order to reduce
+ * latency in the common case where expedited grace periods are
+ * rare. We check mutex_is_locked() to avoid pathological levels of
+ * memory contention on ->exp_funnel_mutex in the heavy-load case.
+ */
+ rnp0 = rcu_get_root(rsp);
+ if (!mutex_is_locked(&rnp0->exp_funnel_mutex)) {
+ if (mutex_trylock(&rnp0->exp_funnel_mutex)) {
+ if (sync_exp_work_done(rsp, rnp0, NULL,
+ &rsp->expedited_workdone0, s))
+ return NULL;
+ return rnp0;
+ }
+ }
+
/*
* Each pass through the following loop works its way
* up the rcu_node tree, returning if others have done the
static const char * const buf[] = RCU_NODE_NAME_INIT;
static const char * const fqs[] = RCU_FQS_NAME_INIT;
static const char * const exp[] = RCU_EXP_NAME_INIT;
+ static const char * const exp_sched[] = RCU_EXP_SCHED_NAME_INIT;
static u8 fl_mask = 0x1;
int levelcnt[RCU_NUM_LVLS]; /* # nodes in each level. */
INIT_LIST_HEAD(&rnp->blkd_tasks);
rcu_init_one_nocb(rnp);
mutex_init(&rnp->exp_funnel_mutex);
- lockdep_set_class_and_name(&rnp->exp_funnel_mutex,
- &rcu_exp_class[i], exp[i]);
+ if (rsp == &rcu_sched_state)
+ lockdep_set_class_and_name(
+ &rnp->exp_funnel_mutex,
+ &rcu_exp_sched_class[i], exp_sched[i]);
+ else
+ lockdep_set_class_and_name(
+ &rnp->exp_funnel_mutex,
+ &rcu_exp_class[i], exp[i]);
}
}
projects / cascardo / linux.git / blobdiff