Commit c24501b2 authored by Joel Fernandes (Google)'s avatar Joel Fernandes (Google) Committed by Paul E. McKenney
Browse files

locktorture: Make the rt_boost factor a tunable 



The rt boosting in locktorture has a factor variable s currently large enough
that boosting only happens once every minute or so. Add a tunable to reduce the
factor so that boosting happens more often, to test paths and arrive at failure
modes earlier. With this change, I can set the factor to like 50 and have the
boosting happens every 10 seconds or so.

Tested with boot parameters:
locktorture.torture_type=mutex_lock
locktorture.onoff_interval=1
locktorture.nwriters_stress=8
locktorture.stutter=0
locktorture.rt_boost=1
locktorture.rt_boost_factor=50
locktorture.nlocks=3

Signed-off-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Reviewed-by: default avatarDavidlohr Bueso <dave@stgolabs.net>
Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent e01f3a1a

kernel/locking/locktorture.c

+7 −5
Original line number Diff line number Diff line
@@ -48,6 +48,7 @@ torture_param(int, stat_interval, 60, 
torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");

torture_param(int, rt_boost, 2,

		"Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");

torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");

torture_param(int, verbose, 1,

	     "Enable verbose debugging printk()s");
@@ -131,12 +132,12 @@ static void torture_lock_busted_write_unlock(int tid __maybe_unused) 


static void __torture_rt_boost(struct torture_random_state *trsp)

{

	const unsigned int factor = 50000; /* yes, quite arbitrary */

	const unsigned int factor = rt_boost_factor;



	if (!rt_task(current)) {

		/*

		 * Boost priority once every ~50k operations. When the

		 * task tries to take the lock, the rtmutex it will account

		 * Boost priority once every rt_boost_factor operations. When

		 * the task tries to take the lock, the rtmutex it will account

		 * for the new priority, and do any corresponding pi-dance.

		 */

		if (trsp && !(torture_random(trsp) %
@@ -146,8 +147,9 @@ static void __torture_rt_boost(struct torture_random_state *trsp) 
			return;

	} else {

		/*

		 * The task will remain boosted for another ~500k operations,

		 * then restored back to its original prio, and so forth.

		 * The task will remain boosted for another 10 * rt_boost_factor

		 * operations, then restored back to its original prio, and so

		 * forth.

		 *

		 * When @trsp is nil, we want to force-reset the task for

		 * stopping the kthread.