Re: [PATCH] sched/core: Fix cpu controller for !RT_GROUP_SCHED

From: Juri Lelli
Date: Wed Jun 19 2019 - 08:39:18 EST


On 19/06/19 11:29, Michal Koutný wrote:
> On Wed, Jun 05, 2019 at 04:20:03PM +0200, Michal Koutný <mkoutny@xxxxxxxx> wrote:
> > I considered relaxing the check to non-root cgroups only, however, as
> > your example shows, it doesn't prevent reaching the avoided state by
> > other paths. I'm not that familiar with RT sched to tell whether
> > RT-priority tasks in different task_groups break any assumptions.
> So I had another look and the check is bogus.
> The RT sched with !CONFIG_RT_GROUP_SCHED works only with the struct
> rt_rq embedded in the generic struct rq -- regardless of the task's
> membership in the cpu controller hierarchy.


> Perhaps, the commit message may mention this also prevents enabling cpu
> controller on unified hierarchy (if there are any (kernel) RT tasks to
> migrate).

Sure. Can add such a comment.

> Reviewed-by: Michal Koutný <mkoutny@xxxxxxxx>