Commit 450d461a authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu-tasks: Add kernel boot parameters for callback laziness 



This commit adds kernel boot parameters for callback laziness, allowing
the RCU Tasks flavors to be individually adjusted.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 5ae769c6

Documentation/admin-guide/kernel-parameters.txt

+23 −0
Original line number Diff line number Diff line
@@ -5293,6 +5293,29 @@ 
			A change in value does not take effect until

			the beginning of the next grace period.



	rcupdate.rcu_tasks_lazy_ms= [KNL]

			Set timeout in milliseconds RCU Tasks asynchronous

			callback batching for call_rcu_tasks().

			A negative value will take the default.  A value

			of zero will disable batching.	Batching is

			always disabled for synchronize_rcu_tasks().



	rcupdate.rcu_tasks_rude_lazy_ms= [KNL]

			Set timeout in milliseconds RCU Tasks

			Rude asynchronous callback batching for

			call_rcu_tasks_rude().	A negative value

			will take the default.	A value of zero will

			disable batching.  Batching is always disabled

			for synchronize_rcu_tasks_rude().



	rcupdate.rcu_tasks_trace_lazy_ms= [KNL]

			Set timeout in milliseconds RCU Tasks

			Trace asynchronous callback batching for

			call_rcu_tasks_trace().  A negative value

			will take the default.	A value of zero will

			disable batching.  Batching is always disabled

			for synchronize_rcu_tasks_trace().



	rcupdate.rcu_self_test= [KNL]

			Run the RCU early boot self tests

kernel/rcu/tasks.h

+15 −0
Original line number Diff line number Diff line
@@ -1083,11 +1083,16 @@ void rcu_barrier_tasks(void) 
}

EXPORT_SYMBOL_GPL(rcu_barrier_tasks);



int rcu_tasks_lazy_ms = -1;

module_param(rcu_tasks_lazy_ms, int, 0444);



static int __init rcu_spawn_tasks_kthread(void)

{

	cblist_init_generic(&rcu_tasks);

	rcu_tasks.gp_sleep = HZ / 10;

	rcu_tasks.init_fract = HZ / 10;

	if (rcu_tasks_lazy_ms >= 0)

		rcu_tasks.lazy_jiffies = msecs_to_jiffies(rcu_tasks_lazy_ms);

	rcu_tasks.pregp_func = rcu_tasks_pregp_step;

	rcu_tasks.pertask_func = rcu_tasks_pertask;

	rcu_tasks.postscan_func = rcu_tasks_postscan;
@@ -1236,10 +1241,15 @@ void rcu_barrier_tasks_rude(void) 
}

EXPORT_SYMBOL_GPL(rcu_barrier_tasks_rude);



int rcu_tasks_rude_lazy_ms = -1;

module_param(rcu_tasks_rude_lazy_ms, int, 0444);



static int __init rcu_spawn_tasks_rude_kthread(void)

{

	cblist_init_generic(&rcu_tasks_rude);

	rcu_tasks_rude.gp_sleep = HZ / 10;

	if (rcu_tasks_rude_lazy_ms >= 0)

		rcu_tasks_rude.lazy_jiffies = msecs_to_jiffies(rcu_tasks_rude_lazy_ms);

	rcu_spawn_tasks_kthread_generic(&rcu_tasks_rude);

	return 0;

}
@@ -1856,6 +1866,9 @@ void rcu_barrier_tasks_trace(void) 
}

EXPORT_SYMBOL_GPL(rcu_barrier_tasks_trace);



int rcu_tasks_trace_lazy_ms = -1;

module_param(rcu_tasks_trace_lazy_ms, int, 0444);



static int __init rcu_spawn_tasks_trace_kthread(void)

{

	cblist_init_generic(&rcu_tasks_trace);
@@ -1870,6 +1883,8 @@ static int __init rcu_spawn_tasks_trace_kthread(void) 
		if (rcu_tasks_trace.init_fract <= 0)

			rcu_tasks_trace.init_fract = 1;

	}

	if (rcu_tasks_trace_lazy_ms >= 0)

		rcu_tasks_trace.lazy_jiffies = msecs_to_jiffies(rcu_tasks_trace_lazy_ms);

	rcu_tasks_trace.pregp_func = rcu_tasks_trace_pregp_step;

	rcu_tasks_trace.postscan_func = rcu_tasks_trace_postscan;

	rcu_tasks_trace.holdouts_func = check_all_holdout_tasks_trace;