[PATCH rcu 05/14] rcuscale: Dump grace-period statistics when rcu_scale_writer() stalls

[neeraj . upadhyay]

From: "Paul E. McKenney" <paul...@kernel.org>

This commit adds a .stats function pointer to the rcu_scale_ops structure,
and if this is non-NULL, it is invoked after stack traces are dumped in
response to a rcu_scale_writer() stall.

Signed-off-by: "Paul E. McKenney" <paul...@kernel.org>
Signed-off-by: Neeraj Upadhyay <neeraj.upadh...@kernel.org>
---
 kernel/rcu/rcuscale.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/kernel/rcu/rcuscale.c b/kernel/rcu/rcuscale.c
index 5087ca7062d9..1b9a43653d7e 100644
--- a/kernel/rcu/rcuscale.c
+++ b/kernel/rcu/rcuscale.c
@@ -145,6 +145,7 @@ struct rcu_scale_ops {
        void (*sync)(void);
        void (*exp_sync)(void);
        struct task_struct *(*rso_gp_kthread)(void);
+       void (*stats)(void);
        const char *name;
 };
 
@@ -226,6 +227,11 @@ static void srcu_scale_synchronize(void)
        synchronize_srcu(srcu_ctlp);
 }
 
+static void srcu_scale_stats(void)
+{
+       srcu_torture_stats_print(srcu_ctlp, scale_type, SCALE_FLAG);
+}
+
 static void srcu_scale_synchronize_expedited(void)
 {
        synchronize_srcu_expedited(srcu_ctlp);
@@ -243,6 +249,7 @@ static struct rcu_scale_ops srcu_ops = {
        .gp_barrier     = srcu_rcu_barrier,
        .sync           = srcu_scale_synchronize,
        .exp_sync       = srcu_scale_synchronize_expedited,
+       .stats          = srcu_scale_stats,
        .name           = "srcu"
 };
 
@@ -272,6 +279,7 @@ static struct rcu_scale_ops srcud_ops = {
        .gp_barrier     = srcu_rcu_barrier,
        .sync           = srcu_scale_synchronize,
        .exp_sync       = srcu_scale_synchronize_expedited,
+       .stats          = srcu_scale_stats,
        .name           = "srcud"
 };
 
@@ -563,6 +571,8 @@ rcu_scale_writer(void *arg)
                                        pr_info("%s: Task %ld flags writer 
%d:\n", __func__, me, i);
                                        sched_show_task(writer_tasks[i]);
                                }
+                               if (cur_ops->stats)
+                                       cur_ops->stats();
                        }
                }
                if (started && !alldone && i < MAX_MEAS - 1)
-- 
2.40.1