[PATCH v2 0/2] isolation: Exclude dynamically isolated CPUs from housekeeping cpumasks

[Waiman Long <longman@redhat.com>]

 v2:
  - Add a TODO comment on overriding boot time housekeeping masks setting
    in the future when dynamic CPU isolation is good enough to deprecate
    isolcpus and nohz_full boot command line parameters.
  - Only save one copy of the boot time housekeeping mask as the CPU
    list used in isolcpus and nohz_full must be the same.
  - Include more housekeeping masks to be updated by cpuset.

 [v1] https://lore.kernel.org/lkml/20240229021414.508972-1-longman@redhat.com/

The housekeeping CPU masks, set up by the "isolcpus" and "nohz_full"
boot command line options, are used at boot time to exclude selected
CPUs from running some kernel housekeeping processes to minimize
disturbance to latency sensitive userspace applications. However, some
of housekeeping CPU masks are also checked at run time to avoid using
those isolated CPUs.

The purpose of this patch series is to exclude dynamically isolated
CPUs from some housekeeping masks so that subsystems that check the
housekeeping masks at run time will not see those isolated CPUs. It does
not migrate the housekeeping processes that have been running on those
newly isolated CPUs since bootup to other CPUs. That will hopefully be
done in the near future.

This patch series updates all the housekeeping cpumasks except the
HK_TYPE_TICK and HK_TYPE_MANAGED_IRQ which needs further investigation.

Waiman Long (2):
  sched/isolation: Exclude dynamically isolated CPUs from housekeeping
    masks
  cgroup/cpuset: Exclude isolated CPUs from housekeeping CPU masks

 include/linux/sched/isolation.h |   8 +++
 kernel/cgroup/cpuset.c          |  34 ++++++++--
 kernel/sched/isolation.c        | 112 +++++++++++++++++++++++++++++++-
 3 files changed, 146 insertions(+), 8 deletions(-)

-- 
2.43.5