anolis: sched: Ensure the logic of check_preempt_tick with CONFIG_GROUP_IDENTITY off

ANBZ: torvalds#471

If we turn CONFIG_GROUP_IDENTITY off, is_highclass() will return false, which
will result in that check_preempt_tick() returns immediately, and this is not
right. To solved this problem, we just judge whether
delta_exec < sysctl_sched_min_granularity if CONFIG_GROUP_IDENTITY is off.

Signed-off-by: Peng Wang <[email protected]>
Signed-off-by: Cruz Zhao <[email protected]>
Signed-off-by: Shile Zhang <[email protected]>
Acked-by: Michael Wang <[email protected]>

Author: Peng Wang

kernel/sched/fair.c

@@ -5546,7 +5546,11 @@ check_preempt_tick(struct cfs_rq *cfs_rq, struct sched_entity *curr)
 	 * narrow margin doesn't have to wait for a full slice.
 	 * This also mitigates buddy induced latencies under load.
 	 */
+#ifdef CONFIG_GROUP_IDENTITY
 	if (is_highclass(curr) && delta_exec < sysctl_sched_min_granularity)
+#else
+	if (delta_exec < sysctl_sched_min_granularity)
+#endif
 		return;
 
 	/* Must be on expel if no next se, and curr won't be expellee */