[PATCH RESEND v2 0/3] condition EAS enablement on FI support

[Ionela Voinescu]

Given the maturity gained by cpufreq-based Frequency Invariance (FI)
support following the patches at [1], this series conditions Energy
Aware Scheduling (EAS) enablement on a frequency invariant system.

Currently, EAS can be enabled on a system without FI support, leading
to incorrect (energy-wise) task placements. As no warning is emitted,
it could take some debugging effort to track the behavior back to the
lack of FI support; this series changes that by disabling EAS
(and advertising it) when FI support is missing.

The series is structured as follows:
 - 1/3 - create function that can rebuild the scheduling and EAS'
   performance domains if EAS' initial conditions change
 - 2/3 - arm64: rebuild scheduling and performance domains in the
         case of late, counter-driven FI initialisation.
 - 3/3 - condition EAS enablement on FI support

RESEND v2: rebase and retest on v5.10-rc1

v1 -> v2:
 - v1 can be found at [2]
 - 1/2 - moved now "static inline" rebuild_sched_domains_energy() stub
   in sched/topology.h header, as suggested by Quentin.
 - Changed the order of 2/3 and 3/3 to maintain bisection as suggested
   by Quentin.
 - 3/3 - place the warning under sched_debug() as per Quentin and
   Dietmar's recommendations.

[1] Most recent version at:
https://lore.kernel.org/lkml/20200901205549.30096-1-ionela.voinescu@xxxxxxx/
[2] https://lore.kernel.org/lkml/20200924123937.20938-1-ionela.voinescu@xxxxxxx/

Many thanks,
Ionela.

Ionela Voinescu (3):
  sched/topology,schedutil: wrap sched domains rebuild
  arm64: rebuild sched domains on invariance status changes
  sched/topology: condition EAS enablement on FIE support

 arch/arm64/kernel/topology.c     | 10 ++++++++++
 include/linux/sched/topology.h   |  8 ++++++++
 kernel/sched/cpufreq_schedutil.c |  9 +--------
 kernel/sched/topology.c          | 27 ++++++++++++++++++++-------
 4 files changed, 39 insertions(+), 15 deletions(-)


base-commit: 3650b228f83adda7e5ee532e2b90429c03f7b9ec
-- 
2.17.1