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-rw-r--r--kernel/rcu/tree_plugin.h98
1 files changed, 58 insertions, 40 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 84fbee4686d3..7fd12039e512 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -182,7 +182,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
raw_lockdep_assert_held_rcu_node(rnp);
WARN_ON_ONCE(rdp->mynode != rnp);
- WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1);
+ WARN_ON_ONCE(!rcu_is_leaf_node(rnp));
/*
* Decide where to queue the newly blocked task. In theory,
@@ -384,6 +384,50 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp)
}
/*
+ * Preemptible RCU implementation for rcu_read_lock().
+ * Just increment ->rcu_read_lock_nesting, shared state will be updated
+ * if we block.
+ */
+void __rcu_read_lock(void)
+{
+ current->rcu_read_lock_nesting++;
+ barrier(); /* critical section after entry code. */
+}
+EXPORT_SYMBOL_GPL(__rcu_read_lock);
+
+/*
+ * Preemptible RCU implementation for rcu_read_unlock().
+ * Decrement ->rcu_read_lock_nesting. If the result is zero (outermost
+ * rcu_read_unlock()) and ->rcu_read_unlock_special is non-zero, then
+ * invoke rcu_read_unlock_special() to clean up after a context switch
+ * in an RCU read-side critical section and other special cases.
+ */
+void __rcu_read_unlock(void)
+{
+ struct task_struct *t = current;
+
+ if (t->rcu_read_lock_nesting != 1) {
+ --t->rcu_read_lock_nesting;
+ } else {
+ barrier(); /* critical section before exit code. */
+ t->rcu_read_lock_nesting = INT_MIN;
+ barrier(); /* assign before ->rcu_read_unlock_special load */
+ if (unlikely(READ_ONCE(t->rcu_read_unlock_special.s)))
+ rcu_read_unlock_special(t);
+ barrier(); /* ->rcu_read_unlock_special load before assign */
+ t->rcu_read_lock_nesting = 0;
+ }
+#ifdef CONFIG_PROVE_LOCKING
+ {
+ int rrln = READ_ONCE(t->rcu_read_lock_nesting);
+
+ WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2);
+ }
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
+}
+EXPORT_SYMBOL_GPL(__rcu_read_unlock);
+
+/*
* Advance a ->blkd_tasks-list pointer to the next entry, instead
* returning NULL if at the end of the list.
*/
@@ -489,7 +533,7 @@ void rcu_read_unlock_special(struct task_struct *t)
rnp = t->rcu_blocked_node;
raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */
WARN_ON_ONCE(rnp != t->rcu_blocked_node);
- WARN_ON_ONCE(rnp->level != rcu_num_lvls - 1);
+ WARN_ON_ONCE(!rcu_is_leaf_node(rnp));
empty_norm = !rcu_preempt_blocked_readers_cgp(rnp);
empty_exp = sync_rcu_preempt_exp_done(rnp);
smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */
@@ -685,15 +729,6 @@ static void rcu_preempt_check_callbacks(void)
t->rcu_read_unlock_special.b.need_qs = true;
}
-#ifdef CONFIG_RCU_BOOST
-
-static void rcu_preempt_do_callbacks(void)
-{
- rcu_do_batch(rcu_state_p, this_cpu_ptr(rcu_data_p));
-}
-
-#endif /* #ifdef CONFIG_RCU_BOOST */
-
/**
* call_rcu() - Queue an RCU callback for invocation after a grace period.
* @head: structure to be used for queueing the RCU updates.
@@ -1140,7 +1175,7 @@ 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();
+ rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data));
}
static void rcu_cpu_kthread_setup(unsigned int cpu)
@@ -1607,7 +1642,7 @@ static int rcu_oom_notify(struct notifier_block *self,
for_each_online_cpu(cpu) {
smp_call_function_single(cpu, rcu_oom_notify_cpu, NULL, 1);
- cond_resched_rcu_qs();
+ cond_resched_tasks_rcu_qs();
}
/* Unconditionally decrement: no need to wake ourselves up. */
@@ -1780,19 +1815,6 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
swake_up_all(sq);
}
-/*
- * Set the root rcu_node structure's ->need_future_gp field
- * based on the sum of those of all rcu_node structures. This does
- * double-count the root rcu_node structure's requests, but this
- * is necessary to handle the possibility of a rcu_nocb_kthread()
- * having awakened during the time that the rcu_node structures
- * were being updated for the end of the previous grace period.
- */
-static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq)
-{
- rnp->need_future_gp[(rnp->completed + 1) & 0x1] += nrq;
-}
-
static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
{
return &rnp->nocb_gp_wq[rnp->completed & 0x1];
@@ -1966,7 +1988,7 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp,
trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
TPS("WakeOvf"));
} else {
- wake_nocb_leader_defer(rdp, RCU_NOCB_WAKE,
+ wake_nocb_leader_defer(rdp, RCU_NOCB_WAKE_FORCE,
TPS("WakeOvfIsDeferred"));
}
rdp->qlen_last_fqs_check = LONG_MAX / 2;
@@ -2048,7 +2070,8 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
struct rcu_node *rnp = rdp->mynode;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
- needwake = rcu_start_future_gp(rnp, rdp, &c);
+ c = rcu_cbs_completed(rdp->rsp, rnp);
+ needwake = rcu_start_this_gp(rnp, rdp, c);
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (needwake)
rcu_gp_kthread_wake(rdp->rsp);
@@ -2057,7 +2080,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
* Wait for the grace period. Do so interruptibly to avoid messing
* up the load average.
*/
- trace_rcu_future_gp(rnp, rdp, c, TPS("StartWait"));
+ trace_rcu_this_gp(rnp, rdp, c, TPS("StartWait"));
for (;;) {
swait_event_interruptible(
rnp->nocb_gp_wq[c & 0x1],
@@ -2065,9 +2088,9 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
if (likely(d))
break;
WARN_ON(signal_pending(current));
- trace_rcu_future_gp(rnp, rdp, c, TPS("ResumeWait"));
+ trace_rcu_this_gp(rnp, rdp, c, TPS("ResumeWait"));
}
- trace_rcu_future_gp(rnp, rdp, c, TPS("EndWait"));
+ trace_rcu_this_gp(rnp, rdp, c, TPS("EndWait"));
smp_mb(); /* Ensure that CB invocation happens after GP end. */
}
@@ -2236,7 +2259,7 @@ static int rcu_nocb_kthread(void *arg)
cl++;
c++;
local_bh_enable();
- cond_resched_rcu_qs();
+ cond_resched_tasks_rcu_qs();
list = next;
}
trace_rcu_batch_end(rdp->rsp->name, c, !!list, 0, 0, 1);
@@ -2292,7 +2315,7 @@ static void do_nocb_deferred_wakeup(struct rcu_data *rdp)
void __init rcu_init_nohz(void)
{
int cpu;
- bool need_rcu_nocb_mask = true;
+ bool need_rcu_nocb_mask = false;
struct rcu_state *rsp;
#if defined(CONFIG_NO_HZ_FULL)
@@ -2315,7 +2338,7 @@ void __init rcu_init_nohz(void)
#endif /* #if defined(CONFIG_NO_HZ_FULL) */
if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
- pr_info("\tNote: kernel parameter 'rcu_nocbs=' contains nonexistent CPUs.\n");
+ pr_info("\tNote: kernel parameter 'rcu_nocbs=', 'nohz_full', or 'isolcpus=' contains nonexistent CPUs.\n");
cpumask_and(rcu_nocb_mask, cpu_possible_mask,
rcu_nocb_mask);
}
@@ -2495,10 +2518,6 @@ static void rcu_nocb_gp_cleanup(struct swait_queue_head *sq)
{
}
-static void rcu_nocb_gp_set(struct rcu_node *rnp, int nrq)
-{
-}
-
static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp)
{
return NULL;
@@ -2587,8 +2606,7 @@ static bool rcu_nohz_full_cpu(struct rcu_state *rsp)
}
/*
- * Bind the grace-period kthread for the sysidle flavor of RCU to the
- * timekeeping CPU.
+ * Bind the RCU grace-period kthreads to the housekeeping CPU.
*/
static void rcu_bind_gp_kthread(void)
{