sched: Implement hierarchical task accounting for SCHED_OTHER
Introduce hierarchical task accounting for the group scheduling case in CFS, as
well as promoting the responsibility for maintaining rq->nr_running to the
scheduling classes.
The primary motivation for this is that with scheduling classes supporting
bandwidth throttling it is possible for entities participating in throttled
sub-trees to not have root visible changes in rq->nr_running across activate
and de-activate operations. This in turn leads to incorrect idle and
weight-per-task load balance decisions.
This also allows us to make a small fixlet to the fastpath in pick_next_task()
under group scheduling.
Note: this issue also exists with the existing sched_rt throttling mechanism.
This patch does not address that.
Signed-off-by: Paul Turner <[email protected]>
Reviewed-by: Hidetoshi Seto <[email protected]>
Signed-off-by: Peter Zijlstra <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>
4 files changed
