diff options
| -rw-r--r-- | kernel/rcu/tasks.h | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 9d3eddaecfde..231a949cdb81 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -24,6 +24,8 @@ typedef void (*postgp_func_t)(struct rcu_tasks *rtp); * struct rcu_tasks_percpu - Per-CPU component of definition for a Tasks-RCU-like mechanism. * @cblist: Callback list. * @lock: Lock protecting per-CPU callback list. + * @rtp_jiffies: Jiffies counter value for statistics. + * @rtp_n_lock_retries: Rough lock-contention statistic. * @rtp_work: Work queue for invoking callbacks. * @barrier_q_head: RCU callback for barrier operation. * @cpu: CPU number corresponding to this entry. @@ -32,6 +34,8 @@ typedef void (*postgp_func_t)(struct rcu_tasks *rtp); struct rcu_tasks_percpu { struct rcu_segcblist cblist; raw_spinlock_t __private lock; + unsigned long rtp_jiffies; + unsigned long rtp_n_lock_retries; struct work_struct rtp_work; struct rcu_head barrier_q_head; int cpu; @@ -231,6 +235,7 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func, struct rcu_tasks *rtp) { unsigned long flags; + unsigned long j; bool needwake; struct rcu_tasks_percpu *rtpcp; @@ -239,7 +244,15 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func, local_irq_save(flags); rtpcp = per_cpu_ptr(rtp->rtpcpu, smp_processor_id() >> READ_ONCE(rtp->percpu_enqueue_shift)); - raw_spin_lock_rcu_node(rtpcp); // irqs already disabled. + if (!raw_spin_trylock_rcu_node(rtpcp)) { // irqs already disabled. + raw_spin_lock_rcu_node(rtpcp); // irqs already disabled. + j = jiffies; + if (rtpcp->rtp_jiffies != j) { + rtpcp->rtp_jiffies = j; + rtpcp->rtp_n_lock_retries = 0; + } + rtpcp->rtp_n_lock_retries++; + } if (!rcu_segcblist_is_enabled(&rtpcp->cblist)) { raw_spin_unlock_rcu_node(rtpcp); // irqs remain disabled. cblist_init_generic(rtp); |