From e01f3a1a589e314cf27bd2cb27d9c2c58e105a27 Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Tue, 13 Dec 2022 20:48:38 +0000 Subject: locktorture: Allow non-rtmutex lock types to be boosted Currently RT boosting is only done for rtmutex_lock, however with proxy execution, we also have the mutex_lock participating in priorities. To exercise the testing better, add RT boosting to other lock testing types as well, using a new knob (rt_boost). 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=1 locktorture.nlocks=3 Signed-off-by: Joel Fernandes (Google) Signed-off-by: Paul E. McKenney --- kernel/locking/locktorture.c | 99 +++++++++++++++++++++++++------------------- 1 file changed, 56 insertions(+), 43 deletions(-) (limited to 'kernel/locking') diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index 9c2fb613a55d..e2271e8fc302 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -46,6 +46,8 @@ torture_param(int, shutdown_secs, 0, "Shutdown time (j), <= zero to disable."); torture_param(int, stat_interval, 60, "Number of seconds between stats printk()s"); 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, verbose, 1, "Enable verbose debugging printk()s"); @@ -127,15 +129,49 @@ static void torture_lock_busted_write_unlock(int tid __maybe_unused) /* BUGGY, do not use in real life!!! */ } -static void torture_boost_dummy(struct torture_random_state *trsp) +static void __torture_rt_boost(struct torture_random_state *trsp) { - /* Only rtmutexes care about priority */ + const unsigned int factor = 50000; /* yes, quite arbitrary */ + + if (!rt_task(current)) { + /* + * Boost priority once every ~50k 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) % + (cxt.nrealwriters_stress * factor))) { + sched_set_fifo(current); + } else /* common case, do nothing */ + return; + } else { + /* + * The task will remain boosted for another ~500k 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. + */ + if (!trsp || !(torture_random(trsp) % + (cxt.nrealwriters_stress * factor * 2))) { + sched_set_normal(current, 0); + } else /* common case, do nothing */ + return; + } +} + +static void torture_rt_boost(struct torture_random_state *trsp) +{ + if (rt_boost != 2) + return; + + __torture_rt_boost(trsp); } static struct lock_torture_ops lock_busted_ops = { .writelock = torture_lock_busted_write_lock, .write_delay = torture_lock_busted_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_lock_busted_write_unlock, .readlock = NULL, .read_delay = NULL, @@ -179,7 +215,7 @@ __releases(torture_spinlock) static struct lock_torture_ops spin_lock_ops = { .writelock = torture_spin_lock_write_lock, .write_delay = torture_spin_lock_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_spin_lock_write_unlock, .readlock = NULL, .read_delay = NULL, @@ -206,7 +242,7 @@ __releases(torture_spinlock) static struct lock_torture_ops spin_lock_irq_ops = { .writelock = torture_spin_lock_write_lock_irq, .write_delay = torture_spin_lock_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_lock_spin_write_unlock_irq, .readlock = NULL, .read_delay = NULL, @@ -275,7 +311,7 @@ __releases(torture_rwlock) static struct lock_torture_ops rw_lock_ops = { .writelock = torture_rwlock_write_lock, .write_delay = torture_rwlock_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_rwlock_write_unlock, .readlock = torture_rwlock_read_lock, .read_delay = torture_rwlock_read_delay, @@ -318,7 +354,7 @@ __releases(torture_rwlock) static struct lock_torture_ops rw_lock_irq_ops = { .writelock = torture_rwlock_write_lock_irq, .write_delay = torture_rwlock_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_rwlock_write_unlock_irq, .readlock = torture_rwlock_read_lock_irq, .read_delay = torture_rwlock_read_delay, @@ -358,7 +394,7 @@ __releases(torture_mutex) static struct lock_torture_ops mutex_lock_ops = { .writelock = torture_mutex_lock, .write_delay = torture_mutex_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_mutex_unlock, .readlock = NULL, .read_delay = NULL, @@ -456,7 +492,7 @@ static struct lock_torture_ops ww_mutex_lock_ops = { .exit = torture_ww_mutex_exit, .writelock = torture_ww_mutex_lock, .write_delay = torture_mutex_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_ww_mutex_unlock, .readlock = NULL, .read_delay = NULL, @@ -474,37 +510,6 @@ __acquires(torture_rtmutex) return 0; } -static void torture_rtmutex_boost(struct torture_random_state *trsp) -{ - const unsigned int factor = 50000; /* yes, quite arbitrary */ - - if (!rt_task(current)) { - /* - * Boost priority once every ~50k 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) % - (cxt.nrealwriters_stress * factor))) { - sched_set_fifo(current); - } else /* common case, do nothing */ - return; - } else { - /* - * The task will remain boosted for another ~500k 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. - */ - if (!trsp || !(torture_random(trsp) % - (cxt.nrealwriters_stress * factor * 2))) { - sched_set_normal(current, 0); - } else /* common case, do nothing */ - return; - } -} - static void torture_rtmutex_delay(struct torture_random_state *trsp) { const unsigned long shortdelay_us = 2; @@ -530,10 +535,18 @@ __releases(torture_rtmutex) rt_mutex_unlock(&torture_rtmutex); } +static void torture_rt_boost_rtmutex(struct torture_random_state *trsp) +{ + if (!rt_boost) + return; + + __torture_rt_boost(trsp); +} + static struct lock_torture_ops rtmutex_lock_ops = { .writelock = torture_rtmutex_lock, .write_delay = torture_rtmutex_delay, - .task_boost = torture_rtmutex_boost, + .task_boost = torture_rt_boost_rtmutex, .writeunlock = torture_rtmutex_unlock, .readlock = NULL, .read_delay = NULL, @@ -600,7 +613,7 @@ __releases(torture_rwsem) static struct lock_torture_ops rwsem_lock_ops = { .writelock = torture_rwsem_down_write, .write_delay = torture_rwsem_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_rwsem_up_write, .readlock = torture_rwsem_down_read, .read_delay = torture_rwsem_read_delay, @@ -652,7 +665,7 @@ static struct lock_torture_ops percpu_rwsem_lock_ops = { .exit = torture_percpu_rwsem_exit, .writelock = torture_percpu_rwsem_down_write, .write_delay = torture_rwsem_write_delay, - .task_boost = torture_boost_dummy, + .task_boost = torture_rt_boost, .writeunlock = torture_percpu_rwsem_up_write, .readlock = torture_percpu_rwsem_down_read, .read_delay = torture_rwsem_read_delay, -- cgit v1.2.3 From c24501b240741907ddfce52ffc186792db5ad3a5 Mon Sep 17 00:00:00 2001 From: "Joel Fernandes (Google)" Date: Tue, 13 Dec 2022 20:48:39 +0000 Subject: 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) Reviewed-by: Davidlohr Bueso Signed-off-by: Paul E. McKenney --- kernel/locking/locktorture.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) (limited to 'kernel/locking') 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. -- cgit v1.2.3