linux-kernel - [PATCH 0/7] Fix relationship between uclamp and fits

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Date:   Wed, 29 Jun 2022 20:46:25 +0100
From:   Qais Yousef <qais.yousef@....com>
To:     Ingo Molnar <mingo@...nel.org>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>
Cc:     linux-kernel@...r.kernel.org, Xuewen Yan <xuewen.yan94@...il.com>,
        Wei Wang <wvw@...gle.com>,
        Jonathan JMChen <Jonathan.JMChen@...iatek.com>,
        Hank <han.lin@...iatek.com>, Qais Yousef <qais.yousef@....com>
Subject: [PATCH 0/7] Fix relationship between uclamp and fits_capacity()

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
-- 
2.25.1