From: Connor O'Brien <[email protected]>
Currently shuffling sets the same cpu affinities for all tasks,
which makes us less likely to hit paths involving migrating
blocked tasks onto a cpu where they can't run.
This patch adds an element of randomness to allow affinities of
different writer tasks to diverge.
This has helped uncover issues in testing with Proxy Execution
Cc: Davidlohr Bueso <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Valentin Schneider <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: [email protected]
Signed-off-by: Connor O'Brien <[email protected]>
Signed-off-by: John Stultz <[email protected]>
---
kernel/torture.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/torture.c b/kernel/torture.c
index 1a0519b836ac..8be83fdc6be1 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -54,6 +54,9 @@ module_param(verbose_sleep_frequency, int, 0444);
static int verbose_sleep_duration = 1;
module_param(verbose_sleep_duration, int, 0444);
+static int random_shuffle;
+module_param(random_shuffle, int, 0444);
+
static char *torture_type;
static int verbose;
@@ -518,6 +521,7 @@ static void torture_shuffle_task_unregister_all(void)
*/
static void torture_shuffle_tasks(void)
{
+ DEFINE_TORTURE_RANDOM(rand);
struct shuffle_task *stp;
cpumask_setall(shuffle_tmp_mask);
@@ -537,8 +541,10 @@ static void torture_shuffle_tasks(void)
cpumask_clear_cpu(shuffle_idle_cpu, shuffle_tmp_mask);
mutex_lock(&shuffle_task_mutex);
- list_for_each_entry(stp, &shuffle_task_list, st_l)
- set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
+ list_for_each_entry(stp, &shuffle_task_list, st_l) {
+ if (!random_shuffle || torture_random(&rand) & 0x1)
+ set_cpus_allowed_ptr(stp->st_t, shuffle_tmp_mask);
+ }
mutex_unlock(&shuffle_task_mutex);
cpus_read_unlock();
--
2.41.0.rc2.161.g9c6817b8e7-goog
From: Dietmar Eggemann <[email protected]>
Modifies locktorture writer to run as RT task.
To use it:
insmod /lib/modules/torture.ko random_shuffle=1 lock_torture_writer_fifo=1
^^^^^^^^^^^^^^^^^^^^^^^^^^
insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3
This patch has been helpful to uncover issues with the proxy-execution
seires.
Cc: Davidlohr Bueso <[email protected]>
Cc: "Paul E. McKenney" <[email protected]>
Cc: Josh Triplett <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Juri Lelli <[email protected]>
Cc: Valentin Schneider <[email protected]>
Cc: Dietmar Eggemann <[email protected]>
Cc: [email protected]
Signed-off-by: Dietmar Eggemann <[email protected]>
[jstultz: Include header change to build, reword commit message]
Signed-off-by: John Stultz <[email protected]>
---
kernel/locking/locktorture.c | 3 ++-
kernel/torture.c | 11 ++++++++++-
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 153ddc4c47ef..7cb044fc99b2 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -816,7 +816,8 @@ static int lock_torture_writer(void *arg)
bool skip_main_lock;
VERBOSE_TOROUT_STRING("lock_torture_writer task started");
- set_user_nice(current, MAX_NICE);
+ if (!rt_task(current))
+ set_user_nice(current, MAX_NICE);
do {
if ((torture_random(&rand) & 0xfffff) == 0)
diff --git a/kernel/torture.c b/kernel/torture.c
index 8be83fdc6be1..db79197e257a 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -37,6 +37,7 @@
#include <linux/ktime.h>
#include <asm/byteorder.h>
#include <linux/torture.h>
+#include <linux/sched/rt.h>
#include "rcu/rcu.h"
MODULE_LICENSE("GPL");
@@ -57,6 +58,9 @@ module_param(verbose_sleep_duration, int, 0444);
static int random_shuffle;
module_param(random_shuffle, int, 0444);
+static int lock_torture_writer_fifo;
+module_param(lock_torture_writer_fifo, int, 0444);
+
static char *torture_type;
static int verbose;
@@ -734,7 +738,7 @@ bool stutter_wait(const char *title)
cond_resched_tasks_rcu_qs();
spt = READ_ONCE(stutter_pause_test);
for (; spt; spt = READ_ONCE(stutter_pause_test)) {
- if (!ret) {
+ if (!ret && !rt_task(current)) {
sched_set_normal(current, MAX_NICE);
ret = true;
}
@@ -944,6 +948,11 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
*tp = NULL;
return ret;
}
+
+ if (lock_torture_writer_fifo &&
+ !strncmp(s, "lock_torture_writer", strlen(s)))
+ sched_set_fifo(*tp);
+
wake_up_process(*tp); // Process is sleeping, so ordering provided.
torture_shuffle_task_register(*tp);
return ret;
--
2.41.0.rc2.161.g9c6817b8e7-goog
On Fri, Jun 02, 2023 at 10:02:10PM +0000, John Stultz wrote:
> From: Dietmar Eggemann <[email protected]>
>
> Modifies locktorture writer to run as RT task.
>
> To use it:
> insmod /lib/modules/torture.ko random_shuffle=1 lock_torture_writer_fifo=1
> ^^^^^^^^^^^^^^^^^^^^^^^^^^
> insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3
>
> This patch has been helpful to uncover issues with the proxy-execution
> seires.
>
> Cc: Davidlohr Bueso <[email protected]>
> Cc: "Paul E. McKenney" <[email protected]>
> Cc: Josh Triplett <[email protected]>
> Cc: Joel Fernandes <[email protected]>
> Cc: Juri Lelli <[email protected]>
> Cc: Valentin Schneider <[email protected]>
> Cc: Dietmar Eggemann <[email protected]>
> Cc: [email protected]
> Signed-off-by: Dietmar Eggemann <[email protected]>
> [jstultz: Include header change to build, reword commit message]
> Signed-off-by: John Stultz <[email protected]>
Queued and pushed, thank you all!
Thanx, Paul
> ---
> kernel/locking/locktorture.c | 3 ++-
> kernel/torture.c | 11 ++++++++++-
> 2 files changed, 12 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
> index 153ddc4c47ef..7cb044fc99b2 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -816,7 +816,8 @@ static int lock_torture_writer(void *arg)
> bool skip_main_lock;
>
> VERBOSE_TOROUT_STRING("lock_torture_writer task started");
> - set_user_nice(current, MAX_NICE);
> + if (!rt_task(current))
> + set_user_nice(current, MAX_NICE);
>
> do {
> if ((torture_random(&rand) & 0xfffff) == 0)
> diff --git a/kernel/torture.c b/kernel/torture.c
> index 8be83fdc6be1..db79197e257a 100644
> --- a/kernel/torture.c
> +++ b/kernel/torture.c
> @@ -37,6 +37,7 @@
> #include <linux/ktime.h>
> #include <asm/byteorder.h>
> #include <linux/torture.h>
> +#include <linux/sched/rt.h>
> #include "rcu/rcu.h"
>
> MODULE_LICENSE("GPL");
> @@ -57,6 +58,9 @@ module_param(verbose_sleep_duration, int, 0444);
> static int random_shuffle;
> module_param(random_shuffle, int, 0444);
>
> +static int lock_torture_writer_fifo;
> +module_param(lock_torture_writer_fifo, int, 0444);
> +
> static char *torture_type;
> static int verbose;
>
> @@ -734,7 +738,7 @@ bool stutter_wait(const char *title)
> cond_resched_tasks_rcu_qs();
> spt = READ_ONCE(stutter_pause_test);
> for (; spt; spt = READ_ONCE(stutter_pause_test)) {
> - if (!ret) {
> + if (!ret && !rt_task(current)) {
> sched_set_normal(current, MAX_NICE);
> ret = true;
> }
> @@ -944,6 +948,11 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
> *tp = NULL;
> return ret;
> }
> +
> + if (lock_torture_writer_fifo &&
> + !strncmp(s, "lock_torture_writer", strlen(s)))
> + sched_set_fifo(*tp);
> +
> wake_up_process(*tp); // Process is sleeping, so ordering provided.
> torture_shuffle_task_register(*tp);
> return ret;
> --
> 2.41.0.rc2.161.g9c6817b8e7-goog
>
On Sat, 03 Jun 2023, Paul E. McKenney wrote:
>On Fri, Jun 02, 2023 at 10:02:10PM +0000, John Stultz wrote:
>> From: Dietmar Eggemann <[email protected]>
>>
>> Modifies locktorture writer to run as RT task.
>>
>> To use it:
>> insmod /lib/modules/torture.ko random_shuffle=1 lock_torture_writer_fifo=1
>> ^^^^^^^^^^^^^^^^^^^^^^^^^^
>> insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3
>>
>> This patch has been helpful to uncover issues with the proxy-execution
>> seires.
>>
>> Cc: Davidlohr Bueso <[email protected]>
>> Cc: "Paul E. McKenney" <[email protected]>
>> Cc: Josh Triplett <[email protected]>
>> Cc: Joel Fernandes <[email protected]>
>> Cc: Juri Lelli <[email protected]>
>> Cc: Valentin Schneider <[email protected]>
>> Cc: Dietmar Eggemann <[email protected]>
>> Cc: [email protected]
>> Signed-off-by: Dietmar Eggemann <[email protected]>
>> [jstultz: Include header change to build, reword commit message]
>> Signed-off-by: John Stultz <[email protected]>
>
>Queued and pushed, thank you all!
Both look good to me. Feel free to add my:
Acked-by: Davidlohr Bueso <[email protected]>
On Sat, Jun 03, 2023 at 10:34:14AM -0700, Davidlohr Bueso wrote:
> On Sat, 03 Jun 2023, Paul E. McKenney wrote:
>
> > On Fri, Jun 02, 2023 at 10:02:10PM +0000, John Stultz wrote:
> > > From: Dietmar Eggemann <[email protected]>
> > >
> > > Modifies locktorture writer to run as RT task.
> > >
> > > To use it:
> > > insmod /lib/modules/torture.ko random_shuffle=1 lock_torture_writer_fifo=1
> > > ^^^^^^^^^^^^^^^^^^^^^^^^^^
> > > insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3
> > >
> > > This patch has been helpful to uncover issues with the proxy-execution
> > > seires.
> > >
> > > Cc: Davidlohr Bueso <[email protected]>
> > > Cc: "Paul E. McKenney" <[email protected]>
> > > Cc: Josh Triplett <[email protected]>
> > > Cc: Joel Fernandes <[email protected]>
> > > Cc: Juri Lelli <[email protected]>
> > > Cc: Valentin Schneider <[email protected]>
> > > Cc: Dietmar Eggemann <[email protected]>
> > > Cc: [email protected]
> > > Signed-off-by: Dietmar Eggemann <[email protected]>
> > > [jstultz: Include header change to build, reword commit message]
> > > Signed-off-by: John Stultz <[email protected]>
> >
> > Queued and pushed, thank you all!
>
> Both look good to me. Feel free to add my:
>
> Acked-by: Davidlohr Bueso <[email protected]>
Thank you! I will apply this on my next rebase.
Thanx, Paul