[PATCH 0/7] Harden preferred CPUs management

[Yury Norov <ynorov@nvidia.com>]

On top of tip sched/core.

This series hardens preferred CPU mask management against CPU hotplug and
prevents competing governors from overriding each other’s selections.

This is partially a resend of [1], excluding the write access, and
partially the new material.

The write access to the preferred cpumask is a subject of the ongoing
discussion. I'll submit it as a follow up shortly.

[1] https://lore.kernel.org/all/20261101192203.6979-1-ynorov@nvidia.com/

Yury Norov (7):
  cpumask: add reset_preferred_cpumask() helper
  sched: restore preferred CPUs when hotplug removes the last one
  virt: steal_governor: remove the minimum elapsed-time check
  virt: steal_governor: serialize sampling against CPU hotplug
  virt: steal_governor: warn on unexpected preferred mask states
  virt: steal_governor: restart sampling immediately after CPU hotplug
  cpu: make preferred CPU policy writers mutually exclusive

 Documentation/scheduler/sched-paravirt.rst |  2 +-
 drivers/virt/steal_governor.c              | 82 +++++++++++++++-------
 include/linux/cpumask.h                    | 30 ++++++++
 kernel/sched/core.c                        |  8 +++
 lib/cpumask.c                              | 67 ++++++++++++++++++
 5 files changed, 164 insertions(+), 25 deletions(-)

-- 
2.53.0