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authorJoel Fernandes (Google) <joel@joelfernandes.org>2022-12-13 20:48:39 +0000
committerPaul E. McKenney <paulmck@kernel.org>2023-01-05 12:10:35 -0800
commitc24501b240741907ddfce52ffc186792db5ad3a5 (patch)
treeda1f40a32fd7662cdcede518236e2935a9e4049e /kernel/locking/locktorture.c
parente01f3a1a589e314cf27bd2cb27d9c2c58e105a27 (diff)
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: Joel Fernandes (Google) <joel@joelfernandes.org> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/locking/locktorture.c')
-rw-r--r--kernel/locking/locktorture.c12
1 files changed, 7 insertions, 5 deletions
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index e2271e8fc302..f04b1978899d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -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.