From: Dietmar Eggemann <dietmar.eggemann@xxxxxxx>
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@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>
---
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;
}
--
2.40.1
