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 <pjt@google.com>
Reviewed-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20110721184756.878333391@google.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Paul Turner
2011-07-21 09:43:27 -07:00
committed by Ingo Molnar
parent 5710f15b52
commit 953bfcd10e
4 changed files with 14 additions and 5 deletions

View File

@@ -34,11 +34,13 @@ static struct task_struct *pick_next_task_stop(struct rq *rq)
static void
enqueue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
inc_nr_running(rq);
}
static void
dequeue_task_stop(struct rq *rq, struct task_struct *p, int flags)
{
dec_nr_running(rq);
}
static void yield_task_stop(struct rq *rq)