Re: [RFC v2] sched/rt: Fix RT (group) throttling with nohz_full

[Sebastian Andrzej Siewior]

On 2021-02-02 10:00:10 [+0100], Jonathan Schwender wrote:
> If nohz_full is enabled (more precisely HK_FLAG_TIMER is set), then
> do_sched_rt_period_timer may be called on a housekeeping CPU,
> which would not service the isolated CPU for a non-root cgroup
> (requires a kernel with RT_GROUP_SCHEDULING).
> This causes RT tasks in a non-root cgroup to get throttled
> indefinitely (unless throttling is disabled) once the timer has
> been moved to a housekeeping CPU.
> To fix this, housekeeping CPUs now service all online CPUs
> if HK_FLAG_TIMER (nohz_full) is set.

This originates from
   https://lore.kernel.org/linux-rt-users/b07b6fc7-1a5f-0dcc-ca65-821de96cd8b4@xxxxxxxxx/

Could someone please take a look?

Sebastian