[PATCH 18/23] sched,locktorture: Convert to sched_set_fifo()

From: Peter Zijlstra
Date: Wed Apr 22 2020 - 07:30:41 EST


Because SCHED_FIFO is a broken scheduler model (see previous patches)
take away the priority field, the kernel can't possibly make an
informed decision.

Effectively changes prio from 99 to 50.

Cc: paulmck@xxxxxxxxxx
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
kernel/locking/locktorture.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)

--- a/kernel/locking/locktorture.c
+++ b/kernel/locking/locktorture.c
@@ -436,8 +436,6 @@ static int torture_rtmutex_lock(void) __

static void torture_rtmutex_boost(struct torture_random_state *trsp)
{
- int policy;
- struct sched_param param;
const unsigned int factor = 50000; /* yes, quite arbitrary */

if (!rt_task(current)) {
@@ -448,8 +446,7 @@ static void torture_rtmutex_boost(struct
*/
if (trsp && !(torture_random(trsp) %
(cxt.nrealwriters_stress * factor))) {
- policy = SCHED_FIFO;
- param.sched_priority = MAX_RT_PRIO - 1;
+ sched_set_fifo(current);
} else /* common case, do nothing */
return;
} else {
@@ -462,13 +459,10 @@ static void torture_rtmutex_boost(struct
*/
if (!trsp || !(torture_random(trsp) %
(cxt.nrealwriters_stress * factor * 2))) {
- policy = SCHED_NORMAL;
- param.sched_priority = 0;
+ sched_set_normal(current, 0);
} else /* common case, do nothing */
return;
}
-
- sched_setscheduler_nocheck(current, policy, &param);
}

static void torture_rtmutex_delay(struct torture_random_state *trsp)