Commit edf1c586 authored by Pat Somaru's avatar Pat Somaru Committed by Tejun Heo
Browse files

sched, sched_ext: Disable SM_IDLE/rq empty path when scx_enabled() 



Disable the rq empty path when scx is enabled. SCX must consult the BPF
scheduler (via the dispatch path in balance) to determine if rq is empty.

This fixes stalls when scx is enabled.

Signed-off-by: default avatarPat Somaru <patso@likewhatevs.io>
Fixes: 3dcac251 ("sched/core: Introduce SM_IDLE and an idle re-entry fast-path in __schedule()")
Signed-off-by: default avatarTejun Heo <tj@kernel.org>
parent 7ebd84d6

kernel/sched/core.c

+2 −1
Original line number Diff line number Diff line
@@ -6591,7 +6591,8 @@ static void __sched notrace __schedule(int sched_mode) 
	 */

	prev_state = READ_ONCE(prev->__state);

	if (sched_mode == SM_IDLE) {

		if (!rq->nr_running) {

		/* SCX must consult the BPF scheduler to tell if rq is empty */

		if (!rq->nr_running && !scx_enabled()) {

			next = prev;

			goto picked;

		}