[PATCH 0/7] Fix relationship between uclamp and fits_capacity()

From: Qais Yousef
Date: Wed Jun 29 2022 - 15:47:57 EST


Relationship between uclamp and fits_capacity() is currently broken. Mostly due
to how uclamp should interact with migration margin and capacity pressure. But
also due not all users were converted to consider uclamp before calling
fits_capacity(). Namely cpu_overutilized().

The meat of the series is patch 1 where we introduce a new function,
util_fits_cpu(), that takes uclamp into account. The new function should
replace all call sits to fits_capacity(), which what subsequent patches do.
Except for patch 7 where we fix handling of early exit condition in
find_energy_efficient_cpu(AKA feec()) that must be uclamp aware too.

util_fits_cpu() will revert back to a simple call to fits_capacity() if uclamp
is not being used on the system.

Qais Yousef (7):
sched/uclamp: Fix relationship between uclamp and migration margin
sched/uclamp: Make task_fits_capacity() use util_fits_cpu()
sched/uclamp: Fix fits_capacity() check in feec()
sched/uclamp: Make select_idle_capacity() use util_fits_cpu()
sched/uclamp: Make asym_fits_capacity() use util_fits_cpu()
sched/uclamp: Make cpu_overutilized() use util_fits_cpu()
sched/uclamp: Cater for uclamp in find_energy_efficient_cpu()'s early
exit condition

kernel/sched/core.c | 10 +-
kernel/sched/fair.c | 256 +++++++++++++++++++++++++++++++++-------
kernel/sched/sched.h | 53 ++++++++-
kernel/sched/topology.c | 18 +--
4 files changed, 275 insertions(+), 62 deletions(-)


base-commit: 70fb5ccf2ebb09a0c8ebba775041567812d45f86
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2.25.1