If the rcutree.use_softirq is configured, when RCU Stall event happened, dump status of all rcuc kthreads who due to starvation prevented grace period ends on CPUs that not report quiescent state. Signed-off-by: Zqiang <qiang1.zhang@xxxxxxxxx> --- v1->v2: rework rcuc_kthread_dump function kernel/rcu/tree_stall.h | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h index d7956c03edbd..fcf0b2e1a71c 100644 --- a/kernel/rcu/tree_stall.h +++ b/kernel/rcu/tree_stall.h @@ -465,11 +465,13 @@ static void print_cpu_stall_info(int cpu) falsepositive ? " (false positive?)" : ""); } -static void rcuc_kthread_dump(struct rcu_data *rdp) +static void __rcuc_kthread_dump(int cpu) { - int cpu; - unsigned long j; + struct rcu_data *rdp; struct task_struct *rcuc; + unsigned long j; + + rdp = per_cpu_ptr(&rcu_data, cpu); rcuc = rdp->rcu_cpu_kthread_task; if (!rcuc) @@ -488,6 +490,21 @@ static void rcuc_kthread_dump(struct rcu_data *rdp) dump_cpu_task(cpu); } +static void rcuc_kthread_dump(void) +{ + int cpu; + struct rcu_node *rnp; + unsigned long flags; + + rcu_for_each_leaf_node(rnp) { + raw_spin_lock_irqsave_rcu_node(rnp, flags); + for_each_leaf_node_possible_cpu(rnp, cpu) + if (rnp->qsmask & leaf_node_cpu_bit(rnp, cpu)) + __rcuc_kthread_dump(cpu); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } +} + /* Complain about starvation of grace-period kthread. */ static void rcu_check_gp_kthread_starvation(void) { @@ -597,6 +614,9 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps) if (ndetected) { rcu_dump_cpu_stacks(); + if (!use_softirq) + rcuc_kthread_dump(); + /* Complain about tasks blocking the grace period. */ rcu_for_each_leaf_node(rnp) rcu_print_detail_task_stall_rnp(rnp); @@ -659,11 +679,11 @@ static void print_cpu_stall(unsigned long gps) rcu_check_gp_kthread_expired_fqs_timer(); rcu_check_gp_kthread_starvation(); - if (!use_softirq) - rcuc_kthread_dump(rdp); - rcu_dump_cpu_stacks(); + if (!use_softirq) + rcuc_kthread_dump(); + raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Rewrite if needed in case of slow consoles. */ if (ULONG_CMP_GE(jiffies, READ_ONCE(rcu_state.jiffies_stall))) -- 2.25.1