sched_rr_get_interval: run tests under SCHED_RR policy

Man page says:
 The specified process should be running under the SCHED_RR
 scheduling policy.

sched_rr_get_interval_1-1 can rarely fail if run as
SCHED_OTHER, because time quantum calculated/returned by
get_rr_interval_fair() can change between two calls.
For example it depends on number of running tasks on runq.

This patch sets sched policy to SCHED_RR.

See also:
 http://pubs.opengroup.org/onlinepubs/9699919799/functions/V2_chap02.html#tag_15_08_04_01

Signed-off-by: Jan Stancek <jstancek@redhat.com>
Acked-by: Cyril Hrubis <chrubis@suse.cz>
3 files changed