RCU's synchronous grace periods act quite differently when there is
only one online CPU, especially in the no-op case in kernels built with
CONFIG_PREEMPTION=n. This change in behavior can be important debugging
information, so this commit adds the number of online CPUs to the RCU
CPU stall warning messages.
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
---
kernel/rcu/tree_stall.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 0c5d8516516a..268dd79c58e7 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -565,9 +565,9 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
for_each_possible_cpu(cpu)
totqlen += rcu_get_n_cbs_cpu(cpu);
- pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu)\n",
+ pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)\n",
smp_processor_id(), (long)(jiffies - gps),
- (long)rcu_seq_current(&rcu_state.gp_seq), totqlen);
+ (long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
if (ndetected) {
rcu_dump_cpu_stacks();
@@ -626,9 +626,9 @@ static void print_cpu_stall(unsigned long gps)
raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags);
for_each_possible_cpu(cpu)
totqlen += rcu_get_n_cbs_cpu(cpu);
- pr_cont("\t(t=%lu jiffies g=%ld q=%lu)\n",
+ pr_cont("\t(t=%lu jiffies g=%ld q=%lu ncpus=%d)\n",
jiffies - gps,
- (long)rcu_seq_current(&rcu_state.gp_seq), totqlen);
+ (long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
rcu_check_gp_kthread_expired_fqs_timer();
rcu_check_gp_kthread_starvation();
--
2.31.1.189.g2e36527f23
