From: "Paul E. McKenney" <paul...@kernel.org> This commit adds the start time, in jiffies, of the most recently started rcu_barrier_tasks*() operation to the diagnostic output used by rcuscale. This information can be helpful in distinguishing a hung barrier operation from a long series of barrier operations.
Signed-off-by: "Paul E. McKenney" <paul...@kernel.org> Signed-off-by: Neeraj Upadhyay <neeraj.upadh...@kernel.org> --- kernel/rcu/tasks.h | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h index 5f6d80ce1e47..36be92efb0da 100644 --- a/kernel/rcu/tasks.h +++ b/kernel/rcu/tasks.h @@ -87,6 +87,7 @@ struct rcu_tasks_percpu { * @barrier_q_count: Number of queues being waited on. * @barrier_q_completion: Barrier wait/wakeup mechanism. * @barrier_q_seq: Sequence number for barrier operations. + * @barrier_q_start: Most recent barrier start in jiffies. * @name: This flavor's textual name. * @kname: This flavor's kthread name. */ @@ -122,6 +123,7 @@ struct rcu_tasks { atomic_t barrier_q_count; struct completion barrier_q_completion; unsigned long barrier_q_seq; + unsigned long barrier_q_start; char *name; char *kname; }; @@ -430,6 +432,7 @@ static void __maybe_unused rcu_barrier_tasks_generic(struct rcu_tasks *rtp) mutex_unlock(&rtp->barrier_q_mutex); return; } + rtp->barrier_q_start = jiffies; rcu_seq_start(&rtp->barrier_q_seq); init_completion(&rtp->barrier_q_completion); atomic_set(&rtp->barrier_q_count, 2); @@ -785,8 +788,9 @@ static void rcu_tasks_torture_stats_print_generic(struct rcu_tasks *rtp, char *t pr_cont(".\n"); else pr_cont(" (none).\n"); - pr_alert("\tBarrier seq %lu count %d holdout CPUs ", - data_race(rtp->barrier_q_seq), atomic_read(&rtp->barrier_q_count)); + pr_alert("\tBarrier seq %lu start %lu count %d holdout CPUs ", + data_race(rtp->barrier_q_seq), j - data_race(rtp->barrier_q_start), + atomic_read(&rtp->barrier_q_count)); if (cpumask_available(cm) && !cpumask_empty(cm)) pr_cont(" %*pbl.\n", cpumask_pr_args(cm)); else -- 2.40.1