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torture: Add lock_torture writer_fifo module parameter

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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: 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>
This commit is contained in:
Dietmar Eggemann 2023-06-02 22:02:10 +00:00 committed by Paul E. McKenney
parent 67d5404d27
commit 5d248bb39f
3 changed files with 13 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/admin-guide/kernel-parameters.txt
View File

@ -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.

12
kernel/locking/locktorture.c
View File

@ -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;

3
kernel/torture.c
View File

@ -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;
}