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authorPaul E. McKenney <paulmck@kernel.org>2020-09-02 21:08:41 -0700
committerPaul E. McKenney <paulmck@kernel.org>2020-11-06 17:13:49 -0800
commitfda5ba9ed254727ac5761b81455d8e93c78eba4a (patch)
treef8aabe3c3114b0ed1a35a528edb8925e87671d55 /kernel/torture.c
parent19012b786ecccb29a9fa20c4ec0a67e2cdfbc010 (diff)
torture: Make torture_stutter() use hrtimer
The torture_stutter() function uses schedule_timeout_interruptible() to time the stutter duration, but this can miss race conditions due to its being time-synchronized with everything else that is based on the timer wheels. This commit therefore converts torture_stutter() to use the high-resolution timers via schedule_hrtimeout(), and also to fuzz the stutter interval. While in the area, this commit also limits the spin-loop portion of the stutter_wait() function's wait loop to two jiffies, down from about one second. Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/torture.c')
-rw-r--r--kernel/torture.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/kernel/torture.c b/kernel/torture.c
index be09377af6bc..56ff02bf444f 100644
--- a/kernel/torture.c
+++ b/kernel/torture.c
@@ -641,20 +641,27 @@ EXPORT_SYMBOL_GPL(stutter_wait);
*/
static int torture_stutter(void *arg)
{
+ ktime_t delay;
+ DEFINE_TORTURE_RANDOM(rand);
int wtime;
VERBOSE_TOROUT_STRING("torture_stutter task started");
do {
if (!torture_must_stop() && stutter > 1) {
wtime = stutter;
- if (stutter > HZ + 1) {
+ if (stutter > 2) {
WRITE_ONCE(stutter_pause_test, 1);
- wtime = stutter - HZ - 1;
- schedule_timeout_interruptible(wtime);
- wtime = HZ + 1;
+ wtime = stutter - 3;
+ delay = ktime_divns(NSEC_PER_SEC * wtime, HZ);
+ delay += (torture_random(&rand) >> 3) % NSEC_PER_MSEC;
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_hrtimeout(&delay, HRTIMER_MODE_REL);
+ wtime = 2;
}
WRITE_ONCE(stutter_pause_test, 2);
- schedule_timeout_interruptible(wtime);
+ delay = ktime_divns(NSEC_PER_SEC * wtime, HZ);
+ set_current_state(TASK_INTERRUPTIBLE);
+ schedule_hrtimeout(&delay, HRTIMER_MODE_REL);
}
WRITE_ONCE(stutter_pause_test, 0);
if (!torture_must_stop())

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