[PATCH 05/23] sched,drbd: Convert to sched_set_fifo*()

From: Peter Zijlstra
Date: Wed Apr 22 2020 - 07:29:58 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.

In this case, use fifo_low, because it only cares about being above
SCHED_NORMAL. Effectively changes prio from 2 to 1.

Cc: axboe@xxxxxxxxx
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
drivers/block/drbd/drbd_receiver.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

--- a/drivers/block/drbd/drbd_receiver.c
+++ b/drivers/block/drbd/drbd_receiver.c
@@ -6020,9 +6020,8 @@ int drbd_ack_receiver(struct drbd_thread
unsigned int header_size = drbd_header_size(connection);
int expect = header_size;
bool ping_timeout_active = false;
- struct sched_param param = { .sched_priority = 2 };

- rv = sched_setscheduler(current, SCHED_RR, &param);
+ rv = sched_set_fifo_low(current);
if (rv < 0)
drbd_err(connection, "drbd_ack_receiver: ERROR set priority, ret=%d\n", rv);