diff mbox series

[rcu,11/15] rcutorture: Add reader_flavor parameter for SRCU readers

Message ID 20241015161112.442758-11-paulmck@kernel.org (mailing list archive)
State Not Applicable
Headers show
Series [rcu,01/15] srcu: Rename srcu_might_be_idle() to srcu_should_expedite() | expand

Commit Message

Paul E. McKenney Oct. 15, 2024, 4:11 p.m. UTC
This commit adds an rcutorture.reader_flavor parameter whose bits
correspond to reader flavors.  For example, SRCU's readers are 0x1 for
normal and 0x2 for NMI-safe.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andrii Nakryiko <andrii@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: <bpf@vger.kernel.org>
---
 .../admin-guide/kernel-parameters.txt         |  8 +++++
 kernel/rcu/rcutorture.c                       | 30 ++++++++++++++-----
 2 files changed, 30 insertions(+), 8 deletions(-)

Comments

Neeraj Upadhyay Nov. 12, 2024, 4:42 a.m. UTC | #1
On 10/15/2024 9:41 PM, Paul E. McKenney wrote:
> This commit adds an rcutorture.reader_flavor parameter whose bits
> correspond to reader flavors.  For example, SRCU's readers are 0x1 for
> normal and 0x2 for NMI-safe.
> 
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> Cc: Alexei Starovoitov <ast@kernel.org>
> Cc: Andrii Nakryiko <andrii@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Kent Overstreet <kent.overstreet@linux.dev>
> Cc: <bpf@vger.kernel.org>
> ---
>  .../admin-guide/kernel-parameters.txt         |  8 +++++
>  kernel/rcu/rcutorture.c                       | 30 ++++++++++++++-----
>  2 files changed, 30 insertions(+), 8 deletions(-)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 1518343bbe223..52922727006fc 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -5426,6 +5426,14 @@
>  			The delay, in seconds, between successive
>  			read-then-exit testing episodes.
>  
> +	rcutorture.reader_flavor= [KNL]
> +			A bit mask indicating which readers to use.
> +			If there is more than one bit set, the readers
> +			are entered from low-order bit up, and are
> +			exited in the opposite order.  For SRCU, the
> +			0x1 bit is normal readers and the 0x2 bit is
> +			for NMI-safe readers.
> +
>  	rcutorture.shuffle_interval= [KNL]
>  			Set task-shuffle interval (s).  Shuffling tasks
>  			allows some CPUs to go into dyntick-idle mode
> diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> index f96ab98f8182f..405decec33677 100644
> --- a/kernel/rcu/rcutorture.c
> +++ b/kernel/rcu/rcutorture.c
> @@ -111,6 +111,7 @@ torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disab
>  torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
>  torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
>  torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
> +torture_param(int, reader_flavor, 0x1, "Reader flavors to use, one per bit.");
>  torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
>  torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
>  torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
> @@ -644,10 +645,20 @@ static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
>  
>  static int srcu_torture_read_lock(void)
>  {
> -	if (cur_ops == &srcud_ops)
> -		return srcu_read_lock_nmisafe(srcu_ctlp);
> -	else
> -		return srcu_read_lock(srcu_ctlp);
> +	int idx;
> +	int ret = 0;
> +
> +	if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {

Minor: Maybe use macros in place of 0x1, 0x2, 0x7 as a cleanup later.


- Neeraj

> +		idx = srcu_read_lock(srcu_ctlp);
> +		WARN_ON_ONCE(idx & ~0x1);
> +		ret += idx;
> +	}
> +	if (reader_flavor & 0x2) {
> +		idx = srcu_read_lock_nmisafe(srcu_ctlp);
> +		WARN_ON_ONCE(idx & ~0x1);
> +		ret += idx << 1;
> +	}
> +	return ret;
>  }
>
Paul E. McKenney Nov. 12, 2024, 7:27 p.m. UTC | #2
On Tue, Nov 12, 2024 at 10:12:40AM +0530, Neeraj Upadhyay wrote:
> On 10/15/2024 9:41 PM, Paul E. McKenney wrote:
> > This commit adds an rcutorture.reader_flavor parameter whose bits
> > correspond to reader flavors.  For example, SRCU's readers are 0x1 for
> > normal and 0x2 for NMI-safe.
> > 
> > Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> > Cc: Alexei Starovoitov <ast@kernel.org>
> > Cc: Andrii Nakryiko <andrii@kernel.org>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Kent Overstreet <kent.overstreet@linux.dev>
> > Cc: <bpf@vger.kernel.org>
> > ---
> >  .../admin-guide/kernel-parameters.txt         |  8 +++++
> >  kernel/rcu/rcutorture.c                       | 30 ++++++++++++++-----
> >  2 files changed, 30 insertions(+), 8 deletions(-)
> > 
> > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> > index 1518343bbe223..52922727006fc 100644
> > --- a/Documentation/admin-guide/kernel-parameters.txt
> > +++ b/Documentation/admin-guide/kernel-parameters.txt
> > @@ -5426,6 +5426,14 @@
> >  			The delay, in seconds, between successive
> >  			read-then-exit testing episodes.
> >  
> > +	rcutorture.reader_flavor= [KNL]
> > +			A bit mask indicating which readers to use.
> > +			If there is more than one bit set, the readers
> > +			are entered from low-order bit up, and are
> > +			exited in the opposite order.  For SRCU, the
> > +			0x1 bit is normal readers and the 0x2 bit is
> > +			for NMI-safe readers.
> > +
> >  	rcutorture.shuffle_interval= [KNL]
> >  			Set task-shuffle interval (s).  Shuffling tasks
> >  			allows some CPUs to go into dyntick-idle mode
> > diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
> > index f96ab98f8182f..405decec33677 100644
> > --- a/kernel/rcu/rcutorture.c
> > +++ b/kernel/rcu/rcutorture.c
> > @@ -111,6 +111,7 @@ torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disab
> >  torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
> >  torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
> >  torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
> > +torture_param(int, reader_flavor, 0x1, "Reader flavors to use, one per bit.");
> >  torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
> >  torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
> >  torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
> > @@ -644,10 +645,20 @@ static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
> >  
> >  static int srcu_torture_read_lock(void)
> >  {
> > -	if (cur_ops == &srcud_ops)
> > -		return srcu_read_lock_nmisafe(srcu_ctlp);
> > -	else
> > -		return srcu_read_lock(srcu_ctlp);
> > +	int idx;
> > +	int ret = 0;
> > +
> > +	if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {
> 
> Minor: Maybe use macros in place of 0x1, 0x2, 0x7 as a cleanup later.

Hmmm...

I could move SRCU_READ_FLAVOR_* to include/linux/srcu.h and make
rcutorture use those.  Plus have a combined mask for the instances of 0x7.

Or is there a better way?

							Thanx, Paul

> - Neeraj
> 
> > +		idx = srcu_read_lock(srcu_ctlp);
> > +		WARN_ON_ONCE(idx & ~0x1);
> > +		ret += idx;
> > +	}
> > +	if (reader_flavor & 0x2) {
> > +		idx = srcu_read_lock_nmisafe(srcu_ctlp);
> > +		WARN_ON_ONCE(idx & ~0x1);
> > +		ret += idx << 1;
> > +	}
> > +	return ret;
> >  }
> >  
>
Neeraj Upadhyay Nov. 13, 2024, 3:20 a.m. UTC | #3
>>>  
>>>  static int srcu_torture_read_lock(void)
>>>  {
>>> -	if (cur_ops == &srcud_ops)
>>> -		return srcu_read_lock_nmisafe(srcu_ctlp);
>>> -	else
>>> -		return srcu_read_lock(srcu_ctlp);
>>> +	int idx;
>>> +	int ret = 0;
>>> +
>>> +	if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {
>>
>> Minor: Maybe use macros in place of 0x1, 0x2, 0x7 as a cleanup later.
> 
> Hmmm...
> 
> I could move SRCU_READ_FLAVOR_* to include/linux/srcu.h and make
> rcutorture use those.  Plus have a combined mask for the instances of 0x7.
> 
> Or is there a better way?
> 

Yes, I was thinking the same. This looks good.


- Neeraj
diff mbox series

Patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1518343bbe223..52922727006fc 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5426,6 +5426,14 @@ 
 			The delay, in seconds, between successive
 			read-then-exit testing episodes.
 
+	rcutorture.reader_flavor= [KNL]
+			A bit mask indicating which readers to use.
+			If there is more than one bit set, the readers
+			are entered from low-order bit up, and are
+			exited in the opposite order.  For SRCU, the
+			0x1 bit is normal readers and the 0x2 bit is
+			for NMI-safe readers.
+
 	rcutorture.shuffle_interval= [KNL]
 			Set task-shuffle interval (s).  Shuffling tasks
 			allows some CPUs to go into dyntick-idle mode
diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index f96ab98f8182f..405decec33677 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -111,6 +111,7 @@  torture_param(int, nocbs_nthreads, 0, "Number of NOCB toggle threads, 0 to disab
 torture_param(int, nocbs_toggle, 1000, "Time between toggling nocb state (ms)");
 torture_param(int, read_exit_delay, 13, "Delay between read-then-exit episodes (s)");
 torture_param(int, read_exit_burst, 16, "# of read-then-exit bursts per episode, zero to disable");
+torture_param(int, reader_flavor, 0x1, "Reader flavors to use, one per bit.");
 torture_param(int, shuffle_interval, 3, "Number of seconds between shuffles");
 torture_param(int, shutdown_secs, 0, "Shutdown time (s), <= zero to disable.");
 torture_param(int, stall_cpu, 0, "Stall duration (s), zero to disable.");
@@ -644,10 +645,20 @@  static void srcu_get_gp_data(int *flags, unsigned long *gp_seq)
 
 static int srcu_torture_read_lock(void)
 {
-	if (cur_ops == &srcud_ops)
-		return srcu_read_lock_nmisafe(srcu_ctlp);
-	else
-		return srcu_read_lock(srcu_ctlp);
+	int idx;
+	int ret = 0;
+
+	if ((reader_flavor & 0x1) || !(reader_flavor & 0x7)) {
+		idx = srcu_read_lock(srcu_ctlp);
+		WARN_ON_ONCE(idx & ~0x1);
+		ret += idx;
+	}
+	if (reader_flavor & 0x2) {
+		idx = srcu_read_lock_nmisafe(srcu_ctlp);
+		WARN_ON_ONCE(idx & ~0x1);
+		ret += idx << 1;
+	}
+	return ret;
 }
 
 static void
@@ -671,10 +682,11 @@  srcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
 
 static void srcu_torture_read_unlock(int idx)
 {
-	if (cur_ops == &srcud_ops)
-		srcu_read_unlock_nmisafe(srcu_ctlp, idx);
-	else
-		srcu_read_unlock(srcu_ctlp, idx);
+	WARN_ON_ONCE((reader_flavor && (idx & ~reader_flavor)) || (!reader_flavor && (idx & ~0x1)));
+	if (reader_flavor & 0x2)
+		srcu_read_unlock_nmisafe(srcu_ctlp, (idx & 0x2) >> 1);
+	if ((reader_flavor & 0x1) || !(reader_flavor & 0x7))
+		srcu_read_unlock(srcu_ctlp, idx & 0x1);
 }
 
 static int torture_srcu_read_lock_held(void)
@@ -2389,6 +2401,7 @@  rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
 		 "n_barrier_cbs=%d "
 		 "onoff_interval=%d onoff_holdoff=%d "
 		 "read_exit_delay=%d read_exit_burst=%d "
+		 "reader_flavor=%x "
 		 "nocbs_nthreads=%d nocbs_toggle=%d "
 		 "test_nmis=%d\n",
 		 torture_type, tag, nrealreaders, nfakewriters,
@@ -2401,6 +2414,7 @@  rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, const char *tag)
 		 n_barrier_cbs,
 		 onoff_interval, onoff_holdoff,
 		 read_exit_delay, read_exit_burst,
+		 reader_flavor,
 		 nocbs_nthreads, nocbs_toggle,
 		 test_nmis);
 }