On Mon, Jul 17, 2023 at 11:20:36AM -0700, Paul E. McKenney wrote:
> From: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
>
> 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
> series.
>
> Cc: "Paul E. McKenney" <paulmck@xxxxxxxxxx>
> Cc: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
> Cc: Joel Fernandes <joel@xxxxxxxxxxxxxxxxx>
> Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
> Cc: Valentin Schneider <vschneid@xxxxxxxxxx>
> Cc: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
> Cc: kernel-team@xxxxxxxxxxx
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
> [jstultz: Include header change to build, reword commit message]
> Signed-off-by: John Stultz <jstultz@xxxxxxxxxx>
> Acked-by: Davidlohr Bueso <dave@xxxxxxxxxxxx>
> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
> ---
> 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 949d3deae506..aac48d323254 100644
> --- a/kernel/locking/locktorture.c
> +++ b/kernel/locking/locktorture.c
> @@ -809,7 +809,8 @@ 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);
I replaced this with a callback function in order to confine
locktorture-specific code to kernel/locking/locktorture.c.
I will reply with the following two patches.
1. Add a kthread-creation callback to _torture_create_kthread().
2. Add lock_torture writer_fifo module parameter, courtesy of
Dietmar Eggemann.
Please let me know if you have objections to this change.
Thanx, Paul
------------------------------------------------------------------------
b/Documentation/admin-guide/kernel-parameters.txt | 4 ++++
b/include/linux/torture.h | 7 +++++--
b/kernel/locking/locktorture.c | 12 +++++++-----
b/kernel/torture.c | 6 +++++-
kernel/torture.c | 3 ++-
5 files changed, 23 insertions(+), 9 deletions(-)
