Commit e34191fa authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Paul E. McKenney
Browse files

locktorture: Support rwlocks 



Add a "rw_lock" torture test to stress kernel rwlocks and their irq
variant. Reader critical regions are 5x longer than writers. As such
a similar ratio of lock acquisitions is seen in the statistics. In the
case of massive contention, both hold the lock for 1/10 of a second.

Signed-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent dd56af42

Documentation/locking/locktorture.txt

+5 −0
Original line number Diff line number Diff line
@@ -45,6 +45,11 @@ torture_type Type of lock to torture. By default, only spinlocks will 
		     o "spin_lock_irq": spin_lock_irq() and spin_unlock_irq()

					pairs.



		     o "rw_lock": read/write lock() and unlock() rwlock pairs.



		     o "rw_lock_irq": read/write lock_irq() and unlock_irq()

				      rwlock pairs.



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



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

kernel/locking/locktorture.c

+112 −3
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/kthread.h>

#include <linux/err.h>

#include <linux/spinlock.h>

#include <linux/rwlock.h>

#include <linux/mutex.h>

#include <linux/smp.h>

#include <linux/interrupt.h>
@@ -229,6 +230,110 @@ static struct lock_torture_ops spin_lock_irq_ops = { 
	.name		= "spin_lock_irq"

};



static DEFINE_RWLOCK(torture_rwlock);



static int torture_rwlock_write_lock(void) __acquires(torture_rwlock)

{

	write_lock(&torture_rwlock);

	return 0;

}



static void torture_rwlock_write_delay(struct torture_random_state *trsp)

{

	const unsigned long shortdelay_us = 2;

	const unsigned long longdelay_ms = 100;



	/* We want a short delay mostly to emulate likely code, and

	 * we want a long delay occasionally to force massive contention.

	 */

	if (!(torture_random(trsp) %

	      (cxt.nrealwriters_stress * 2000 * longdelay_ms)))

		mdelay(longdelay_ms);

	else

		udelay(shortdelay_us);

}



static void torture_rwlock_write_unlock(void) __releases(torture_rwlock)

{

	write_unlock(&torture_rwlock);

}



static int torture_rwlock_read_lock(void) __acquires(torture_rwlock)

{

	read_lock(&torture_rwlock);

	return 0;

}



static void torture_rwlock_read_delay(struct torture_random_state *trsp)

{

	const unsigned long shortdelay_us = 10;

	const unsigned long longdelay_ms = 100;



	/* We want a short delay mostly to emulate likely code, and

	 * we want a long delay occasionally to force massive contention.

	 */

	if (!(torture_random(trsp) %

	      (cxt.nrealreaders_stress * 2000 * longdelay_ms)))

		mdelay(longdelay_ms);

	else

		udelay(shortdelay_us);

}



static void torture_rwlock_read_unlock(void) __releases(torture_rwlock)

{

	read_unlock(&torture_rwlock);

}



static struct lock_torture_ops rw_lock_ops = {

	.writelock	= torture_rwlock_write_lock,

	.write_delay	= torture_rwlock_write_delay,

	.writeunlock	= torture_rwlock_write_unlock,

	.readlock       = torture_rwlock_read_lock,

	.read_delay     = torture_rwlock_read_delay,

	.readunlock     = torture_rwlock_read_unlock,

	.name		= "rw_lock"

};



static int torture_rwlock_write_lock_irq(void) __acquires(torture_rwlock)

{

	unsigned long flags;



	write_lock_irqsave(&torture_rwlock, flags);

	cxt.cur_ops->flags = flags;

	return 0;

}



static void torture_rwlock_write_unlock_irq(void)

__releases(torture_rwlock)

{

	write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);

}



static int torture_rwlock_read_lock_irq(void) __acquires(torture_rwlock)

{

	unsigned long flags;



	read_lock_irqsave(&torture_rwlock, flags);

	cxt.cur_ops->flags = flags;

	return 0;

}



static void torture_rwlock_read_unlock_irq(void)

__releases(torture_rwlock)

{

	write_unlock_irqrestore(&torture_rwlock, cxt.cur_ops->flags);

}



static struct lock_torture_ops rw_lock_irq_ops = {

	.writelock	= torture_rwlock_write_lock_irq,

	.write_delay	= torture_rwlock_write_delay,

	.writeunlock	= torture_rwlock_write_unlock_irq,

	.readlock       = torture_rwlock_read_lock_irq,

	.read_delay     = torture_rwlock_read_delay,

	.readunlock     = torture_rwlock_read_unlock_irq,

	.name		= "rw_lock_irq"

};



static DEFINE_MUTEX(torture_mutex);



static int torture_mutex_lock(void) __acquires(torture_mutex)
@@ -535,8 +640,11 @@ 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, &rwsem_lock_ops,

		&lock_busted_ops,

		&spin_lock_ops, &spin_lock_irq_ops,

		&rw_lock_ops, &rw_lock_irq_ops,

		&mutex_lock_ops,

		&rwsem_lock_ops,

	};



	if (!torture_init_begin(torture_type, verbose, &torture_runnable))
@@ -571,7 +679,8 @@ static int __init lock_torture_init(void) 
		cxt.debug_lock = true;

#endif

#ifdef CONFIG_DEBUG_SPINLOCK

	if (strncmp(torture_type, "spin", 4) == 0)

	if ((strncmp(torture_type, "spin", 4) == 0) ||

	    (strncmp(torture_type, "rw_lock", 7) == 0))

		cxt.debug_lock = true;

#endif

tools/testing/selftests/rcutorture/configs/lock/CFLIST

+1 −0
Original line number Diff line number Diff line 
LOCK01

LOCK02

LOCK03

LOCK04
 
 No newline at end of file

tools/testing/selftests/rcutorture/configs/lock/LOCK04

0 → 100644
+6 −0
Original line number Diff line number Diff line 
CONFIG_SMP=y

CONFIG_NR_CPUS=4

CONFIG_HOTPLUG_CPU=y

CONFIG_PREEMPT_NONE=n

CONFIG_PREEMPT_VOLUNTARY=n

CONFIG_PREEMPT=y

tools/testing/selftests/rcutorture/configs/lock/LOCK04.boot

0 → 100644
+1 −0
Original line number Diff line number Diff line 
locktorture.torture_type=rw_lock

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