Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 4a3b427f authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Paul E. McKenney
Browse files

locktorture: Support rwsems 



We can easily do so with our new reader lock support. Just an arbitrary
design default: readers have higher (5x) critical region latencies than
writers: 50 ms and 10 ms, respectively.

Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 4f6332c1

Documentation/locking/locktorture.txt

+2 −0
Original line number Diff line number Diff line
@@ -47,6 +47,8 @@ torture_type Type of lock to torture. By default, only spinlocks will 


		     o "mutex_lock": mutex_lock() and mutex_unlock() pairs.



		     o "rwsem_lock": read/write down() and up() semaphore pairs.



torture_runnable  Start locktorture at boot time in the case where the

		  module is built into the kernel, otherwise wait for

		  torture_runnable to be set via sysfs before starting.

kernel/locking/locktorture.c

+67 −1
Original line number Diff line number Diff line
@@ -265,6 +265,71 @@ static struct lock_torture_ops mutex_lock_ops = { 
	.name		= "mutex_lock"

};



static DECLARE_RWSEM(torture_rwsem);

static int torture_rwsem_down_write(void) __acquires(torture_rwsem)

{

	down_write(&torture_rwsem);

	return 0;

}



static void torture_rwsem_write_delay(struct torture_random_state *trsp)

{

	const unsigned long longdelay_ms = 100;



	/* We want a long delay occasionally to force massive contention.  */

	if (!(torture_random(trsp) %

	      (nrealwriters_stress * 2000 * longdelay_ms)))

		mdelay(longdelay_ms * 10);

	else

		mdelay(longdelay_ms / 10);

#ifdef CONFIG_PREEMPT

	if (!(torture_random(trsp) % (nrealwriters_stress * 20000)))

		preempt_schedule();  /* Allow test to be preempted. */

#endif

}



static void torture_rwsem_up_write(void) __releases(torture_rwsem)

{

	up_write(&torture_rwsem);

}



static int torture_rwsem_down_read(void) __acquires(torture_rwsem)

{

	down_read(&torture_rwsem);

	return 0;

}



static void torture_rwsem_read_delay(struct torture_random_state *trsp)

{

	const unsigned long longdelay_ms = 100;



	/* We want a long delay occasionally to force massive contention.  */

	if (!(torture_random(trsp) %

	      (nrealwriters_stress * 2000 * longdelay_ms)))

		mdelay(longdelay_ms * 2);

	else

		mdelay(longdelay_ms / 2);

#ifdef CONFIG_PREEMPT

	if (!(torture_random(trsp) % (nrealreaders_stress * 20000)))

		preempt_schedule();  /* Allow test to be preempted. */

#endif

}



static void torture_rwsem_up_read(void) __releases(torture_rwsem)

{

	up_read(&torture_rwsem);

}



static struct lock_torture_ops rwsem_lock_ops = {

	.writelock	= torture_rwsem_down_write,

	.write_delay	= torture_rwsem_write_delay,

	.writeunlock	= torture_rwsem_up_write,

	.readlock       = torture_rwsem_down_read,

	.read_delay     = torture_rwsem_read_delay,

	.readunlock     = torture_rwsem_up_read,

	.name		= "rwsem_lock"

};



/*

 * Lock torture writer kthread.  Repeatedly acquires and releases

 * the lock, checking for duplicate acquisitions.
@@ -467,7 +532,8 @@ static int __init lock_torture_init(void) 
	int i, j;

	int firsterr = 0;

	static struct lock_torture_ops *torture_ops[] = {

		&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops, &mutex_lock_ops,

		&lock_busted_ops, &spin_lock_ops, &spin_lock_irq_ops,

		&mutex_lock_ops, &rwsem_lock_ops,

	};



	if (!torture_init_begin(torture_type, verbose, &torture_runnable))