From: Dietmar Eggemann <dietmar.eggemann@arm.com>
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@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: kernel-team@android.com
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
[jstultz: Include header change to build, reword commit message]
Signed-off-by: John Stultz <jstultz@google.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
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);
+
wake_up_process(*tp); // Process is sleeping, so ordering provided.
torture_shuffle_task_register(*tp);
return ret;
--
2.40.1On Mon, Jul 17, 2023 at 11:20:36AM -0700, Paul E. McKenney wrote:
> From: Dietmar Eggemann <dietmar.eggemann@arm.com>
>
> 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@kernel.org>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Joel Fernandes <joel@joelfernandes.org>
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Valentin Schneider <vschneid@redhat.com>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: kernel-team@android.com
> Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
> [jstultz: Include header change to build, reword commit message]
> Signed-off-by: John Stultz <jstultz@google.com>
> Acked-by: Davidlohr Bueso <dave@stgolabs.net>
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> ---
> 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(-)
This commit adds a kthread-creation callback to the
_torture_create_kthread() function, which allows callers of a new
torture_create_kthread_cb() macro to specify a function to be invoked
after the kthread is created but before it is awakened for the first time.
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: John Stultz <jstultz@google.com>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: kernel-team@android.com
---
include/linux/torture.h | 7 +++++--
kernel/torture.c | 6 +++++-
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/include/linux/torture.h b/include/linux/torture.h
index 7038104463e4..bb466eec01e4 100644
--- a/include/linux/torture.h
+++ b/include/linux/torture.h
@@ -108,12 +108,15 @@ bool torture_must_stop(void);
bool torture_must_stop_irq(void);
void torture_kthread_stopping(char *title);
int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
- char *f, struct task_struct **tp);
+ char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp));
void _torture_stop_kthread(char *m, struct task_struct **tp);
#define torture_create_kthread(n, arg, tp) \
_torture_create_kthread(n, (arg), #n, "Creating " #n " task", \
- "Failed to create " #n, &(tp))
+ "Failed to create " #n, &(tp), NULL)
+#define torture_create_kthread_cb(n, arg, tp, cbf) \
+ _torture_create_kthread(n, (arg), #n, "Creating " #n " task", \
+ "Failed to create " #n, &(tp), cbf)
#define torture_stop_kthread(n, tp) \
_torture_stop_kthread("Stopping " #n " task", &(tp))
diff --git a/kernel/torture.c b/kernel/torture.c
index 8be83fdc6be1..b88a1a86d9da 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -932,7 +932,7 @@ EXPORT_SYMBOL_GPL(torture_kthread_stopping);
* it starts, you will need to open-code your own.
*/
int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
- char *f, struct task_struct **tp)
+ char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp))
{
int ret = 0;
@@ -944,6 +944,10 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
*tp = NULL;
return ret;
}
+
+ if (cbf)
+ cbf(*tp);
+
wake_up_process(*tp); // Process is sleeping, so ordering provided.
torture_shuffle_task_register(*tp);
return ret;
--
2.40.1On Thu, Jul 27, 2023 at 8:22 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > This commit adds a kthread-creation callback to the > _torture_create_kthread() function, which allows callers of a new > torture_create_kthread_cb() macro to specify a function to be invoked > after the kthread is created but before it is awakened for the first time. > > Signed-off-by: Paul E. McKenney <paulmck@kernel.org> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > Cc: John Stultz <jstultz@google.com> > Cc: Josh Triplett <josh@joshtriplett.org> > Cc: Joel Fernandes <joel@joelfernandes.org> > Cc: Juri Lelli <juri.lelli@redhat.com> > Cc: Valentin Schneider <vschneid@redhat.com> > Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> > Cc: kernel-team@android.com Thanks for improving the patch this way! Acked-by: John Stultz <jstultz@google.com>
On Thu, Jul 27, 2023 at 11:22 PM Paul E. McKenney <paulmck@kernel.org> wrote:
>
> This commit adds a kthread-creation callback to the
> _torture_create_kthread() function, which allows callers of a new
> torture_create_kthread_cb() macro to specify a function to be invoked
> after the kthread is created but before it is awakened for the first time.
>
> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: John Stultz <jstultz@google.com>
> Cc: Josh Triplett <josh@joshtriplett.org>
> Cc: Joel Fernandes <joel@joelfernandes.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
thanks,
- Joel
> Cc: Juri Lelli <juri.lelli@redhat.com>
> Cc: Valentin Schneider <vschneid@redhat.com>
> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
> Cc: kernel-team@android.com
> ---
> include/linux/torture.h | 7 +++++--
> kernel/torture.c | 6 +++++-
> 2 files changed, 10 insertions(+), 3 deletions(-)
>
> diff --git a/include/linux/torture.h b/include/linux/torture.h
> index 7038104463e4..bb466eec01e4 100644
> --- a/include/linux/torture.h
> +++ b/include/linux/torture.h
> @@ -108,12 +108,15 @@ bool torture_must_stop(void);
> bool torture_must_stop_irq(void);
> void torture_kthread_stopping(char *title);
> int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
> - char *f, struct task_struct **tp);
> + char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp));
> void _torture_stop_kthread(char *m, struct task_struct **tp);
>
> #define torture_create_kthread(n, arg, tp) \
> _torture_create_kthread(n, (arg), #n, "Creating " #n " task", \
> - "Failed to create " #n, &(tp))
> + "Failed to create " #n, &(tp), NULL)
> +#define torture_create_kthread_cb(n, arg, tp, cbf) \
> + _torture_create_kthread(n, (arg), #n, "Creating " #n " task", \
> + "Failed to create " #n, &(tp), cbf)
> #define torture_stop_kthread(n, tp) \
> _torture_stop_kthread("Stopping " #n " task", &(tp))
>
> diff --git a/kernel/torture.c b/kernel/torture.c
> index 8be83fdc6be1..b88a1a86d9da 100644
> --- a/kernel/torture.c
> +++ b/kernel/torture.c
> @@ -932,7 +932,7 @@ EXPORT_SYMBOL_GPL(torture_kthread_stopping);
> * it starts, you will need to open-code your own.
> */
> int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
> - char *f, struct task_struct **tp)
> + char *f, struct task_struct **tp, void (*cbf)(struct task_struct *tp))
> {
> int ret = 0;
>
> @@ -944,6 +944,10 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
> *tp = NULL;
> return ret;
> }
> +
> + if (cbf)
> + cbf(*tp);
> +
> wake_up_process(*tp); // Process is sleeping, so ordering provided.
> torture_shuffle_task_register(*tp);
> return ret;
> --
> 2.40.1
>
From: Dietmar Eggemann <dietmar.eggemann@arm.com>
This commit adds a module parameter that causes the locktorture writer
to run at real-time priority.
To use it:
insmod /lib/modules/torture.ko random_shuffle=1
insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1
^^^^^^^^^^^^^
A predecessor to this patch has been helpful to uncover issues with the
proxy-execution series.
[ paulmck: Remove locktorture-specific code from kernel/torture.c. ]
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>
Cc: kernel-team@android.com
Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com>
[jstultz: Include header change to build, reword commit message]
Signed-off-by: John Stultz <jstultz@google.com>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ++++
kernel/locking/locktorture.c | 12 +++++++-----
kernel/torture.c | 3 ++-
3 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a1457995fd41..7b94455e9ae2 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -2918,6 +2918,10 @@
locktorture.torture_type= [KNL]
Specify the locking implementation to test.
+ locktorture.writer_fifo= [KNL]
+ Run the write-side locktorture kthreads at
+ sched_set_fifo() real-time priority.
+
locktorture.verbose= [KNL]
Enable additional printk() statements.
diff --git a/kernel/locking/locktorture.c b/kernel/locking/locktorture.c
index 949d3deae506..270c7f80ce84 100644
--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -45,6 +45,7 @@ torture_param(int, stutter, 5, "Number of jiffies to run/halt test, 0=disable");
torture_param(int, rt_boost, 2,
"Do periodic rt-boost. 0=Disable, 1=Only for rt_mutex, 2=For all lock types.");
torture_param(int, rt_boost_factor, 50, "A factor determining how often rt-boost happens.");
+torture_param(int, writer_fifo, 0, "Run writers at sched_set_fifo() priority");
torture_param(int, verbose, 1, "Enable verbose debugging printk()s");
torture_param(int, nested_locks, 0, "Number of nested locks (max = 8)");
/* Going much higher trips "BUG: MAX_LOCKDEP_CHAIN_HLOCKS too low!" errors */
@@ -809,7 +810,8 @@ 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)
@@ -1015,8 +1017,7 @@ static void lock_torture_cleanup(void)
if (writer_tasks) {
for (i = 0; i < cxt.nrealwriters_stress; i++)
- torture_stop_kthread(lock_torture_writer,
- writer_tasks[i]);
+ torture_stop_kthread(lock_torture_writer, writer_tasks[i]);
kfree(writer_tasks);
writer_tasks = NULL;
}
@@ -1244,8 +1245,9 @@ static int __init lock_torture_init(void)
goto create_reader;
/* Create writer. */
- firsterr = torture_create_kthread(lock_torture_writer, &cxt.lwsa[i],
- writer_tasks[i]);
+ firsterr = torture_create_kthread_cb(lock_torture_writer, &cxt.lwsa[i],
+ writer_tasks[i],
+ writer_fifo ? sched_set_fifo : NULL);
if (torture_init_error(firsterr))
goto unwind;
diff --git a/kernel/torture.c b/kernel/torture.c
index b88a1a86d9da..a1ac493488e2 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");
@@ -734,7 +735,7 @@ 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;
}
--
2.40.1On Thu, Jul 27, 2023 at 8:22 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > From: Dietmar Eggemann <dietmar.eggemann@arm.com> > > This commit adds a module parameter that causes the locktorture writer > to run at real-time priority. > > To use it: > insmod /lib/modules/torture.ko random_shuffle=1 > insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1 > ^^^^^^^^^^^^^ > > A predecessor to this patch has been helpful to uncover issues with the > proxy-execution series. > > [ paulmck: Remove locktorture-specific code from kernel/torture.c. ] Thanks again for improving this! I've switched over to your version here in my test tree. Acked-by: John Stultz <jstultz@google.com> thanks -john
On Mon, Aug 07, 2023 at 08:27:29PM -0700, John Stultz wrote: > On Thu, Jul 27, 2023 at 8:22 PM Paul E. McKenney <paulmck@kernel.org> wrote: > > > > From: Dietmar Eggemann <dietmar.eggemann@arm.com> > > > > This commit adds a module parameter that causes the locktorture writer > > to run at real-time priority. > > > > To use it: > > insmod /lib/modules/torture.ko random_shuffle=1 > > insmod /lib/modules/locktorture.ko torture_type=mutex_lock rt_boost=1 rt_boost_factor=50 nested_locks=3 writer_fifo=1 > > ^^^^^^^^^^^^^ > > > > A predecessor to this patch has been helpful to uncover issues with the > > proxy-execution series. > > > > [ paulmck: Remove locktorture-specific code from kernel/torture.c. ] > > Thanks again for improving this! I've switched over to your version > here in my test tree. > > Acked-by: John Stultz <jstultz@google.com> Thank you both! I will apply on my next rebase. Thanx, Paul
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