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-rw-r--r--kernel/rcu/tree.c19
-rw-r--r--kernel/rcu/tree.h1
-rw-r--r--kernel/rcu/tree_plugin.h24
3 files changed, 35 insertions, 9 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 853b79a6ff10..0933d8650890 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -207,6 +207,19 @@ static int rcu_gp_in_progress(void)
return rcu_seq_state(rcu_seq_current(&rcu_state.gp_seq));
}
+/*
+ * Return the number of callbacks queued on the specified CPU.
+ * Handles both the nocbs and normal cases.
+ */
+static long rcu_get_n_cbs_cpu(int cpu)
+{
+ struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+
+ if (rcu_segcblist_is_enabled(&rdp->cblist)) /* Online normal CPU? */
+ return rcu_segcblist_n_cbs(&rdp->cblist);
+ return rcu_get_n_cbs_nocb_cpu(rdp); /* Works for offline, too. */
+}
+
void rcu_softirq_qs(void)
{
rcu_qs();
@@ -1265,8 +1278,7 @@ static void print_other_cpu_stall(unsigned long gp_seq)
print_cpu_stall_info_end();
for_each_possible_cpu(cpu)
- totqlen += rcu_segcblist_n_cbs(&per_cpu_ptr(&rcu_data,
- cpu)->cblist);
+ totqlen += rcu_get_n_cbs_cpu(cpu);
pr_cont("(detected by %d, t=%ld jiffies, g=%ld, q=%lu)\n",
smp_processor_id(), (long)(jiffies - rcu_state.gp_start),
(long)rcu_seq_current(&rcu_state.gp_seq), totqlen);
@@ -1326,8 +1338,7 @@ static void print_cpu_stall(void)
raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags);
print_cpu_stall_info_end();
for_each_possible_cpu(cpu)
- totqlen += rcu_segcblist_n_cbs(&per_cpu_ptr(&rcu_data,
- cpu)->cblist);
+ totqlen += rcu_get_n_cbs_cpu(cpu);
pr_cont(" (t=%lu jiffies g=%ld q=%lu)\n",
jiffies - rcu_state.gp_start,
(long)rcu_seq_current(&rcu_state.gp_seq), totqlen);
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index c3e2807a834a..a8f82b7dc5e2 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -455,6 +455,7 @@ static void __init rcu_spawn_nocb_kthreads(void);
static void __init rcu_organize_nocb_kthreads(void);
#endif /* #ifdef CONFIG_RCU_NOCB_CPU */
static bool init_nocb_callback_list(struct rcu_data *rdp);
+static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp);
static void rcu_bind_gp_kthread(void);
static bool rcu_nohz_full_cpu(void);
static void rcu_dynticks_task_enter(void);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 25fe26c4e9c1..1b3dd2fc0cd6 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -2011,7 +2011,7 @@ static bool rcu_nocb_cpu_needs_barrier(int cpu)
* (if a callback is in fact needed). This is associated with an
* atomic_inc() in the caller.
*/
- ret = atomic_long_read(&rdp->nocb_q_count);
+ ret = rcu_get_n_cbs_nocb_cpu(rdp);
#ifdef CONFIG_PROVE_RCU
rhp = READ_ONCE(rdp->nocb_head);
@@ -2066,7 +2066,7 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp,
TPS("WakeNotPoll"));
return;
}
- len = atomic_long_read(&rdp->nocb_q_count);
+ len = rcu_get_n_cbs_nocb_cpu(rdp);
if (old_rhpp == &rdp->nocb_head) {
if (!irqs_disabled_flags(flags)) {
/* ... if queue was empty ... */
@@ -2115,11 +2115,11 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
trace_rcu_kfree_callback(rcu_state.name, rhp,
(unsigned long)rhp->func,
-atomic_long_read(&rdp->nocb_q_count_lazy),
- -atomic_long_read(&rdp->nocb_q_count));
+ -rcu_get_n_cbs_nocb_cpu(rdp));
else
trace_rcu_callback(rcu_state.name, rhp,
-atomic_long_read(&rdp->nocb_q_count_lazy),
- -atomic_long_read(&rdp->nocb_q_count));
+ -rcu_get_n_cbs_nocb_cpu(rdp));
/*
* If called from an extended quiescent state with interrupts
@@ -2343,7 +2343,7 @@ static int rcu_nocb_kthread(void *arg)
/* Each pass through the following loop invokes a callback. */
trace_rcu_batch_start(rcu_state.name,
atomic_long_read(&rdp->nocb_q_count_lazy),
- atomic_long_read(&rdp->nocb_q_count), -1);
+ rcu_get_n_cbs_nocb_cpu(rdp), -1);
c = cl = 0;
while (list) {
next = list->next;
@@ -2614,6 +2614,15 @@ void rcu_bind_current_to_nocb(void)
}
EXPORT_SYMBOL_GPL(rcu_bind_current_to_nocb);
+/*
+ * Return the number of RCU callbacks still queued from the specified
+ * CPU, which must be a nocbs CPU.
+ */
+static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp)
+{
+ return atomic_long_read(&rdp->nocb_q_count);
+}
+
#else /* #ifdef CONFIG_RCU_NOCB_CPU */
static bool rcu_nocb_cpu_needs_barrier(int cpu)
@@ -2674,6 +2683,11 @@ static bool init_nocb_callback_list(struct rcu_data *rdp)
return false;
}
+static unsigned long rcu_get_n_cbs_nocb_cpu(struct rcu_data *rdp)
+{
+ return 0;
+}
+
#endif /* #else #ifdef CONFIG_RCU_NOCB_CPU */
/*
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