[PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Zqiang]

For PREEMPT_RT kernel, the spin_lock, spin_lock_irq will converted
to sleepable rt_spin_lock and the interrupt related suffix for
spin_lock/unlock(_irq, irqsave/irqrestore) do not affect CPU's
interrupt state. this commit therefore add raw_spin_lock torture
tests, this is a strict spin lock implementation in RT kernels.

Signed-off-by: Zqiang <qiang1.zhang@intel.com>
---
 kernel/locking/locktorture.c | 58 ++++++++++++++++++++++++++++++++++++
 1 file changed, 58 insertions(+)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 9425aff08936..521197366f27 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
 	.name		= "spin_lock_irq"
 };
 
+#ifdef CONFIG_PREEMPT_RT
+static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
+
+static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	raw_spin_lock(&torture_raw_spinlock);
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock(&torture_raw_spinlock);
+}
+
+static struct lock_torture_ops raw_spin_lock_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock"
+};
+
+static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops raw_spin_lock_irq_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock_irq,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock_irq,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock_irq"
+};
+#endif
+
 static DEFINE_RWLOCK(torture_rwlock);
 
 static int torture_rwlock_write_lock(int tid __maybe_unused)
@@ -1017,6 +1072,9 @@ static int __init lock_torture_init(void)
 	static struct lock_torture_ops *torture_ops[] = {
 		&lock_busted_ops,
 		&spin_lock_ops, &spin_lock_irq_ops,
+#ifdef CONFIG_PREEMPT_RT
+		&raw_spin_lock_ops, &raw_spin_lock_irq_ops,
+#endif
 		&rw_lock_ops, &rw_lock_irq_ops,
 		&mutex_lock_ops,
 		&ww_mutex_lock_ops,
-- 
2.25.1

Re: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Paul E. McKenney]

On Wed, Feb 15, 2023 at 02:10:35PM +0800, Zqiang wrote:
> For PREEMPT_RT kernel, the spin_lock, spin_lock_irq will converted
> to sleepable rt_spin_lock and the interrupt related suffix for
> spin_lock/unlock(_irq, irqsave/irqrestore) do not affect CPU's
> interrupt state. this commit therefore add raw_spin_lock torture
> tests, this is a strict spin lock implementation in RT kernels.
> 
> Signed-off-by: Zqiang <qiang1.zhang@intel.com>

A nice addition!  Is this something you will be testing regularly?
If not, should there be additional locktorture scenarios, perhaps prefixed
by "RT-" to hint that they are not normally available?

Or did you have some other plan for making use of these?

						Thanx, Paul

> ---
>  kernel/locking/locktorture.c | 58 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
> 
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index 9425aff08936..521197366f27 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
>  	.name		= "spin_lock_irq"
>  };
>  
> +#ifdef CONFIG_PREEMPT_RT
> +static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
> +
> +static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
> +__acquires(torture_raw_spinlock)
> +{
> +	raw_spin_lock(&torture_raw_spinlock);
> +	return 0;
> +}
> +
> +static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
> +__releases(torture_raw_spinlock)
> +{
> +	raw_spin_unlock(&torture_raw_spinlock);
> +}
> +
> +static struct lock_torture_ops raw_spin_lock_ops = {
> +	.writelock	= torture_raw_spin_lock_write_lock,
> +	.write_delay	= torture_spin_lock_write_delay,
> +	.task_boost	= torture_rt_boost,
> +	.writeunlock	= torture_raw_spin_lock_write_unlock,
> +	.readlock	= NULL,
> +	.read_delay	= NULL,
> +	.readunlock	= NULL,
> +	.name		= "raw_spin_lock"
> +};
> +
> +static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
> +__acquires(torture_raw_spinlock)
> +{
> +	unsigned long flags;
> +
> +	raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
> +	cxt.cur_ops->flags = flags;
> +	return 0;
> +}
> +
> +static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
> +__releases(torture_raw_spinlock)
> +{
> +	raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
> +}
> +
> +static struct lock_torture_ops raw_spin_lock_irq_ops = {
> +	.writelock	= torture_raw_spin_lock_write_lock_irq,
> +	.write_delay	= torture_spin_lock_write_delay,
> +	.task_boost	= torture_rt_boost,
> +	.writeunlock	= torture_raw_spin_lock_write_unlock_irq,
> +	.readlock	= NULL,
> +	.read_delay	= NULL,
> +	.readunlock	= NULL,
> +	.name		= "raw_spin_lock_irq"
> +};
> +#endif
> +
>  static DEFINE_RWLOCK(torture_rwlock);
>  
>  static int torture_rwlock_write_lock(int tid __maybe_unused)
> @@ -1017,6 +1072,9 @@ static int __init lock_torture_init(void)
>  	static struct lock_torture_ops *torture_ops[] = {
>  		&lock_busted_ops,
>  		&spin_lock_ops, &spin_lock_irq_ops,
> +#ifdef CONFIG_PREEMPT_RT
> +		&raw_spin_lock_ops, &raw_spin_lock_irq_ops,
> +#endif
>  		&rw_lock_ops, &rw_lock_irq_ops,
>  		&mutex_lock_ops,
>  		&ww_mutex_lock_ops,
> -- 
> 2.25.1
> 

RE: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Zhang, Qiang1]

>On Wed, Feb 15, 2023 at 02:10:35PM +0800, Zqiang wrote:
> For PREEMPT_RT kernel, the spin_lock, spin_lock_irq will converted
> to sleepable rt_spin_lock and the interrupt related suffix for
> spin_lock/unlock(_irq, irqsave/irqrestore) do not affect CPU's
> interrupt state. this commit therefore add raw_spin_lock torture
> tests, this is a strict spin lock implementation in RT kernels.
> 
> Signed-off-by: Zqiang <qiang1.zhang@intel.com>
>
>A nice addition!  Is this something you will be testing regularly?
>If not, should there be additional locktorture scenarios, perhaps prefixed
>by "RT-" to hint that they are not normally available?
>
>Or did you have some other plan for making use of these?

Hi Paul

Thanks for reply,  in fact, I want to enrich the test of locktorture, 
after all, under the PREEMPT_RT kernel, we lost the test of the
real spin lock. 

Thanks
Zqiang

>
>						Thanx, Paul
>
> ---
>  kernel/locking/locktorture.c | 58 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 58 insertions(+)
> 
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index 9425aff08936..521197366f27 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
>  	.name		= "spin_lock_irq"
>  };
>  
> +#ifdef CONFIG_PREEMPT_RT
> +static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
> +
> +static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
> +__acquires(torture_raw_spinlock)
> +{
> +	raw_spin_lock(&torture_raw_spinlock);
> +	return 0;
> +}
> +
> +static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
> +__releases(torture_raw_spinlock)
> +{
> +	raw_spin_unlock(&torture_raw_spinlock);
> +}
> +
> +static struct lock_torture_ops raw_spin_lock_ops = {
> +	.writelock	= torture_raw_spin_lock_write_lock,
> +	.write_delay	= torture_spin_lock_write_delay,
> +	.task_boost	= torture_rt_boost,
> +	.writeunlock	= torture_raw_spin_lock_write_unlock,
> +	.readlock	= NULL,
> +	.read_delay	= NULL,
> +	.readunlock	= NULL,
> +	.name		= "raw_spin_lock"
> +};
> +
> +static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
> +__acquires(torture_raw_spinlock)
> +{
> +	unsigned long flags;
> +
> +	raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
> +	cxt.cur_ops->flags = flags;
> +	return 0;
> +}
> +
> +static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
> +__releases(torture_raw_spinlock)
> +{
> +	raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
> +}
> +
> +static struct lock_torture_ops raw_spin_lock_irq_ops = {
> +	.writelock	= torture_raw_spin_lock_write_lock_irq,
> +	.write_delay	= torture_spin_lock_write_delay,
> +	.task_boost	= torture_rt_boost,
> +	.writeunlock	= torture_raw_spin_lock_write_unlock_irq,
> +	.readlock	= NULL,
> +	.read_delay	= NULL,
> +	.readunlock	= NULL,
> +	.name		= "raw_spin_lock_irq"
> +};
> +#endif
> +
>  static DEFINE_RWLOCK(torture_rwlock);
>  
>  static int torture_rwlock_write_lock(int tid __maybe_unused)
> @@ -1017,6 +1072,9 @@ static int __init lock_torture_init(void)
>  	static struct lock_torture_ops *torture_ops[] = {
>  		&lock_busted_ops,
>  		&spin_lock_ops, &spin_lock_irq_ops,
> +#ifdef CONFIG_PREEMPT_RT
> +		&raw_spin_lock_ops, &raw_spin_lock_irq_ops,
> +#endif
>  		&rw_lock_ops, &rw_lock_irq_ops,
>  		&mutex_lock_ops,
>  		&ww_mutex_lock_ops,
> -- 
> 2.25.1
> 

Re: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Paul E. McKenney]

On Sun, Feb 19, 2023 at 05:04:41AM +0000, Zhang, Qiang1 wrote:
> 
> >On Wed, Feb 15, 2023 at 02:10:35PM +0800, Zqiang wrote:
> > For PREEMPT_RT kernel, the spin_lock, spin_lock_irq will converted
> > to sleepable rt_spin_lock and the interrupt related suffix for
> > spin_lock/unlock(_irq, irqsave/irqrestore) do not affect CPU's
> > interrupt state. this commit therefore add raw_spin_lock torture
> > tests, this is a strict spin lock implementation in RT kernels.
> > 
> > Signed-off-by: Zqiang <qiang1.zhang@intel.com>
> >
> >A nice addition!  Is this something you will be testing regularly?
> >If not, should there be additional locktorture scenarios, perhaps prefixed
> >by "RT-" to hint that they are not normally available?
> >
> >Or did you have some other plan for making use of these?
> 
> Hi Paul
> 
> Thanks for reply,  in fact, I want to enrich the test of locktorture, 
> after all, under the PREEMPT_RT kernel, we lost the test of the
> real spin lock. 

Very well, how does the following look?

							Thanx, Paul

------------------------------------------------------------------------

commit edc9d419ee8c22821ffd664466a5cf19208c3f02
Author: Zqiang <qiang1.zhang@intel.com>
Date:   Wed Feb 15 14:10:35 2023 +0800

    locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels
    
    In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
    to sleepable rt_spin_lock().  This means that the interrupt related suffix
    for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
    interrupt state. This commit therefore adds raw spin-lock torture tests.
    This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.
    
    Signed-off-by: Zqiang <qiang1.zhang@intel.com>
    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 9425aff089365..ed8e5baafe49f 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
 	.name		= "spin_lock_irq"
 };
 
+#ifdef CONFIG_PREEMPT_RT
+static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
+
+static int torture_raw_spin_lock_write_lock(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	raw_spin_lock(&torture_raw_spinlock);
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock(&torture_raw_spinlock);
+}
+
+static struct lock_torture_ops raw_spin_lock_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock"
+};
+
+static int torture_raw_spin_lock_write_lock_irq(int tid __maybe_unused)
+__acquires(torture_raw_spinlock)
+{
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&torture_raw_spinlock, flags);
+	cxt.cur_ops->flags = flags;
+	return 0;
+}
+
+static void torture_raw_spin_lock_write_unlock_irq(int tid __maybe_unused)
+__releases(torture_raw_spinlock)
+{
+	raw_spin_unlock_irqrestore(&torture_raw_spinlock, cxt.cur_ops->flags);
+}
+
+static struct lock_torture_ops raw_spin_lock_irq_ops = {
+	.writelock	= torture_raw_spin_lock_write_lock_irq,
+	.write_delay	= torture_spin_lock_write_delay,
+	.task_boost	= torture_rt_boost,
+	.writeunlock	= torture_raw_spin_lock_write_unlock_irq,
+	.readlock	= NULL,
+	.read_delay	= NULL,
+	.readunlock	= NULL,
+	.name		= "raw_spin_lock_irq"
+};
+#endif // #ifdef CONFIG_PREEMPT_RT
+
 static DEFINE_RWLOCK(torture_rwlock);
 
 static int torture_rwlock_write_lock(int tid __maybe_unused)
@@ -1017,6 +1072,9 @@ static int __init lock_torture_init(void)
 	static struct lock_torture_ops *torture_ops[] = {
 		&lock_busted_ops,
 		&spin_lock_ops, &spin_lock_irq_ops,
+#ifdef CONFIG_PREEMPT_RT
+		&raw_spin_lock_ops, &raw_spin_lock_irq_ops,
+#endif // #ifdef CONFIG_PREEMPT_RT
 		&rw_lock_ops, &rw_lock_irq_ops,
 		&mutex_lock_ops,
 		&ww_mutex_lock_ops,

Re: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Davidlohr Bueso]

On Wed, 22 Feb 2023, Paul E. McKenney wrote:

>commit edc9d419ee8c22821ffd664466a5cf19208c3f02
>Author: Zqiang <qiang1.zhang@intel.com>
>Date:   Wed Feb 15 14:10:35 2023 +0800
>
>    locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels
>
>    In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
>    to sleepable rt_spin_lock().  This means that the interrupt related suffix
>    for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
>    interrupt state. This commit therefore adds raw spin-lock torture tests.
>    This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.
>
>    Signed-off-by: Zqiang <qiang1.zhang@intel.com>
>    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

This is a nice addition, thanks. Just one comment below.

>diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
>index 9425aff089365..ed8e5baafe49f 100644
>--- a/kernel/locking/locktorture.c
>+++ b/kernel/locking/locktorture.c
>@@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
>	.name		= "spin_lock_irq"
> };
>
>+#ifdef CONFIG_PREEMPT_RT
>+static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);

How about leaving raw spinlocks regardless of preempt-rt, and instead
change the default lock (which is spin_lock) based on CONFIG_PREEMPT_RT
and use the raw one in that case?

Thanks,
Davidlohr

Re: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Paul E. McKenney]

On Wed, Feb 22, 2023 at 07:53:59PM -0800, Davidlohr Bueso wrote:
> On Wed, 22 Feb 2023, Paul E. McKenney wrote:
> 
> > commit edc9d419ee8c22821ffd664466a5cf19208c3f02
> > Author: Zqiang <qiang1.zhang@intel.com>
> > Date:   Wed Feb 15 14:10:35 2023 +0800
> > 
> >    locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels
> > 
> >    In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
> >    to sleepable rt_spin_lock().  This means that the interrupt related suffix
> >    for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
> >    interrupt state. This commit therefore adds raw spin-lock torture tests.
> >    This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.
> > 
> >    Signed-off-by: Zqiang <qiang1.zhang@intel.com>
> >    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> 
> This is a nice addition, thanks. Just one comment below.
> 
> > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> > index 9425aff089365..ed8e5baafe49f 100644
> > --- a/kernel/locking/locktorture.c
> > +++ b/kernel/locking/locktorture.c
> > @@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
> > 	.name		= "spin_lock_irq"
> > };
> > 
> > +#ifdef CONFIG_PREEMPT_RT
> > +static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
> 
> How about leaving raw spinlocks regardless of preempt-rt, and instead
> change the default lock (which is spin_lock) based on CONFIG_PREEMPT_RT
> and use the raw one in that case?

That makes a lot of sense to me!  In fact, I tested this by deleting
those #ifdef statements.  ;-)

Zqiang, would you like to take the patch and make that change, with
attribution?

							Thanx, Paul

RE: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Zhang, Qiang1]

> On Wed, 22 Feb 2023, Paul E. McKenney wrote:
> 
> > commit edc9d419ee8c22821ffd664466a5cf19208c3f02
> > Author: Zqiang <qiang1.zhang@intel.com>
> > Date:   Wed Feb 15 14:10:35 2023 +0800
> > 
> >    locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels
> > 
> >    In PREEMPT_RT kernels, both spin_lock() and spin_lock_irq() are converted
> >    to sleepable rt_spin_lock().  This means that the interrupt related suffix
> >    for spin_lock/unlock(_irq, irqsave/irqrestore) do not affect the CPU's
> >    interrupt state. This commit therefore adds raw spin-lock torture tests.
> >    This in turn permits pure spin locks to be tested in PREEMPT_RT kernels.
> > 
> >    Signed-off-by: Zqiang <qiang1.zhang@intel.com>
> >    Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> 
> This is a nice addition, thanks. Just one comment below.
> 
> > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> > index 9425aff089365..ed8e5baafe49f 100644
> > --- a/kernel/locking/locktorture.c
> > +++ b/kernel/locking/locktorture.c
> > @@ -257,6 +257,61 @@ static struct lock_torture_ops spin_lock_irq_ops = {
> > 	.name		= "spin_lock_irq"
> > };
> > 
> > +#ifdef CONFIG_PREEMPT_RT
> > +static DEFINE_RAW_SPINLOCK(torture_raw_spinlock);
> 
> How about leaving raw spinlocks regardless of preempt-rt, and instead
> change the default lock (which is spin_lock) based on CONFIG_PREEMPT_RT
> and use the raw one in that case?
>
>That makes a lot of sense to me!  In fact, I tested this by deleting
>those #ifdef statements.  ;-)
>
>Zqiang, would you like to take the patch and make that change, with
>attribution?

If I understand correctly, I should remove #ifdef statements, right?
If yes, I will change and resend 😊.

Thanks 
Zqiang

>
>							Thanx, Paul

Re: [PATCH] locktorture: Add raw_spinlock* torture tests for PREEMPT_RT kernels

[Davidlohr Bueso]

On Thu, 23 Feb 2023, Zhang, Qiang1 wrote:

>If I understand correctly, I should remove #ifdef statements, right?

Yes, but also please make torture_type default depend on PREEMPT_RT.

Thanks,
Davidlohr