diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c index c7f264aed5b7a..9425aff089365 100644 --- a/kernel/locking/locktorture.c +++ b/kernel/locking/locktorture.c @@ -760,6 +760,7 @@ static int lock_torture_writer(void *arg) int tid = lwsp - cxt.lwsa; DEFINE_TORTURE_RANDOM(rand); u32 lockset_mask; + bool skip_main_lock; VERBOSE_TOROUT_STRING("lock_torture_writer task started"); set_user_nice(current, MAX_NICE); @@ -769,21 +770,37 @@ static int lock_torture_writer(void *arg) schedule_timeout_uninterruptible(1); lockset_mask = torture_random(&rand); + /* + * When using nested_locks, we want to occasionally + * skip the main lock so we can avoid always serializing + * the lock chains on that central lock. By skipping the + * main lock occasionally, we can create different + * contention patterns (allowing for multiple disjoint + * blocked trees) + */ + skip_main_lock = (nested_locks && + !(torture_random(&rand) % 100)); + cxt.cur_ops->task_boost(&rand); if (cxt.cur_ops->nested_lock) cxt.cur_ops->nested_lock(tid, lockset_mask); - cxt.cur_ops->writelock(tid); - if (WARN_ON_ONCE(lock_is_write_held)) - lwsp->n_lock_fail++; - lock_is_write_held = true; - if (WARN_ON_ONCE(atomic_read(&lock_is_read_held))) - lwsp->n_lock_fail++; /* rare, but... */ - lwsp->n_lock_acquired++; + if (!skip_main_lock) { + cxt.cur_ops->writelock(tid); + if (WARN_ON_ONCE(lock_is_write_held)) + lwsp->n_lock_fail++; + lock_is_write_held = true; + if (WARN_ON_ONCE(atomic_read(&lock_is_read_held))) + lwsp->n_lock_fail++; /* rare, but... */ + + lwsp->n_lock_acquired++; + } cxt.cur_ops->write_delay(&rand); - lock_is_write_held = false; - WRITE_ONCE(last_lock_release, jiffies); - cxt.cur_ops->writeunlock(tid); + if (!skip_main_lock) { + lock_is_write_held = false; + WRITE_ONCE(last_lock_release, jiffies); + cxt.cur_ops->writeunlock(tid); + } if (cxt.cur_ops->nested_unlock) cxt.cur_ops->nested_unlock(tid, lockset_mask);