Re: [PATCH tip/core/rcu 03/28] locktorture: Track time of last ->writeunlock()

[Paul E. McKenney]

On Thu, Nov 05, 2020 at 10:56:42PM -0800, Davidlohr Bueso wrote:
> On Thu, 05 Nov 2020, paul...@kernel.org wrote:
> 
> > From: "Paul E. McKenney" 
> > 
> > This commit adds a last_lock_release variable that tracks the time of
> > the last ->writeunlock() call, which allows easier diagnosing of lock
> > hangs when using a kernel debugger.
> 
> This makes sense to have.
> 
> Acked-by: Davidlohr Bueso 

Will apply, thank you!

Thanx, Paul

> > Cc: Davidlohr Bueso 
> > Signed-off-by: Paul E. McKenney 
> > ---
> > kernel/locking/locktorture.c | 2 ++
> > 1 file changed, 2 insertions(+)
> > 
> > diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> > index 62d215b..316531d 100644
> > --- a/kernel/locking/locktorture.c
> > +++ b/kernel/locking/locktorture.c
> > @@ -60,6 +60,7 @@ static struct task_struct **reader_tasks;
> > 
> > static bool lock_is_write_held;
> > static bool lock_is_read_held;
> > +static unsigned long last_lock_release;
> > 
> > struct lock_stress_stats {
> > long n_lock_fail;
> > @@ -632,6 +633,7 @@ static int lock_torture_writer(void *arg)
> > lwsp->n_lock_acquired++;
> > cxt.cur_ops->write_delay();
> > lock_is_write_held = false;
> > +   WRITE_ONCE(last_lock_release, jiffies);
> > cxt.cur_ops->writeunlock();
> > 
> > stutter_wait("lock_torture_writer");
> > -- 
> > 2.9.5
> > 

Re: [PATCH tip/core/rcu 03/28] locktorture: Track time of last ->writeunlock()

[Davidlohr Bueso]

On Thu, 05 Nov 2020, paul...@kernel.org wrote:


From: "Paul E. McKenney" 

This commit adds a last_lock_release variable that tracks the time of
the last ->writeunlock() call, which allows easier diagnosing of lock
hangs when using a kernel debugger.


This makes sense to have.

Acked-by: Davidlohr Bueso 



Cc: Davidlohr Bueso 
Signed-off-by: Paul E. McKenney 
---
kernel/locking/locktorture.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 62d215b..316531d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -60,6 +60,7 @@ static struct task_struct **reader_tasks;

static bool lock_is_write_held;
static bool lock_is_read_held;
+static unsigned long last_lock_release;

struct lock_stress_stats {
long n_lock_fail;
@@ -632,6 +633,7 @@ static int lock_torture_writer(void *arg)
lwsp->n_lock_acquired++;
cxt.cur_ops->write_delay();
lock_is_write_held = false;
+   WRITE_ONCE(last_lock_release, jiffies);
cxt.cur_ops->writeunlock();

stutter_wait("lock_torture_writer");
--
2.9.5

[PATCH tip/core/rcu 03/28] locktorture: Track time of last ->writeunlock()

[paulmck]

From: "Paul E. McKenney" 

This commit adds a last_lock_release variable that tracks the time of
the last ->writeunlock() call, which allows easier diagnosing of lock
hangs when using a kernel debugger.

Cc: Davidlohr Bueso 
Signed-off-by: Paul E. McKenney 
---
 kernel/locking/locktorture.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 62d215b..316531d 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -60,6 +60,7 @@ static struct task_struct **reader_tasks;
 
 static bool lock_is_write_held;
 static bool lock_is_read_held;
+static unsigned long last_lock_release;
 
 struct lock_stress_stats {
long n_lock_fail;
@@ -632,6 +633,7 @@ static int lock_torture_writer(void *arg)
lwsp->n_lock_acquired++;
cxt.cur_ops->write_delay();
lock_is_write_held = false;
+   WRITE_ONCE(last_lock_release, jiffies);
cxt.cur_ops->writeunlock();
 
stutter_wait("lock_torture_writer");
-- 
2.9.5