rcu-tasks: Add a grace-period start time for throttling and debug
This commit adds a place to record the grace-period start in jiffies.
This will be used by later commits for debugging purposes and to throttle
IPIs early in the grace period.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
diff --git a/kernel/rcu/tasks.h b/kernel/rcu/tasks.h
index 6f8a404..71462cf 100644
--- a/kernel/rcu/tasks.h
+++ b/kernel/rcu/tasks.h
@@ -46,6 +46,7 @@ struct rcu_tasks {
raw_spinlock_t cbs_lock;
int gp_state;
unsigned long gp_jiffies;
+ unsigned long gp_start;
struct task_struct *kthread_ptr;
rcu_tasks_gp_func_t gp_func;
pregp_func_t pregp_func;
@@ -200,6 +201,7 @@ static int __noreturn rcu_tasks_kthread(void *arg)
// Wait for one grace period.
set_tasks_gp_state(rtp, RTGS_WAIT_GP);
+ rtp->gp_start = jiffies;
rtp->gp_func(rtp);
/* Invoke the callbacks. */