Pull power management updates from Rafael Wysocki:
 "These update cpufreq (core and drivers), cpuidle (polling state
  implementation and the PSCI driver), the OPP (operating performance
  points) framework, devfreq (core and drivers), the power capping RAPL
  (Running Average Power Limit) driver, the Energy Model support, the
  generic power domains (genpd) framework, the ACPI device power
  management, the core system-wide suspend code and power management
  utilities.

  Specifics:

   - Use local_clock() instead of jiffies in the cpufreq statistics to
     improve accuracy (Viresh Kumar).

   - Fix up OPP usage in the cpufreq-dt and qcom-cpufreq-nvmem cpufreq
     drivers (Viresh Kumar).

   - Clean up the cpufreq core, the intel_pstate driver and the
     schedutil cpufreq governor (Rafael Wysocki).

   - Fix up error code paths in the sti-cpufreq and mediatek cpufreq
     drivers (Yangtao Li, Qinglang Miao).

   - Fix cpufreq_online() to return error codes instead of success (0)
     in all cases when it fails (Wang ShaoBo).

   - Add mt8167 support to the mediatek cpufreq driver and blacklist
     mt8516 in the cpufreq-dt-platdev driver (Fabien Parent).

   - Modify the tegra194 cpufreq driver to always return values from the
     frequency table as the current frequency and clean up that driver
     (Sumit Gupta, Jon Hunter).

   - Modify the arm_scmi cpufreq driver to allow it to discover the
     power scale present in the performance protocol and provide this
     information to the Energy Model (Lukasz Luba).

   - Add missing MODULE_DEVICE_TABLE to several cpufreq drivers (Pali
     Rohár).

   - Clean up the CPPC cpufreq driver (Ionela Voinescu).

   - Fix NVMEM_IMX_OCOTP dependency in the imx cpufreq driver (Arnd
     Bergmann).

   - Rework the poling interval selection for the polling state in
     cpuidle (Mel Gorman).

   - Enable suspend-to-idle for PSCI OSI mode in the PSCI cpuidle driver
     (Ulf Hansson).

   - Modify the OPP framework to support empty (node-less) OPP tables in
     DT for passing dependency information (Nicola Mazzucato).

   - Fix potential lockdep issue in the OPP core and clean up the OPP
     core (Viresh Kumar).

   - Modify dev_pm_opp_put_regulators() to accept a NULL argument and
     update its users accordingly (Viresh Kumar).

   - Add frequency changes tracepoint to devfreq (Matthias Kaehlcke).

   - Add support for governor feature flags to devfreq, make devfreq
     sysfs file permissions depend on the governor and clean up the
     devfreq core (Chanwoo Choi).

   - Clean up the tegra20 devfreq driver and deprecate it to allow
     another driver based on EMC_STAT to be used instead of it (Dmitry
     Osipenko).

   - Add interconnect support to the tegra30 devfreq driver, allow it to
     take the interconnect and OPP information from DT and clean it up
     (Dmitry Osipenko).

   - Add interconnect support to the exynos-bus devfreq driver along
     with interconnect properties documentation (Sylwester Nawrocki).

   - Add suport for AMD Fam17h and Fam19h processors to the RAPL power
     capping driver (Victor Ding, Kim Phillips).

   - Fix handling of overly long constraint names in the powercap
     framework (Lukasz Luba).

   - Fix the wakeup configuration handling for bridges in the ACPI
     device power management core (Rafael Wysocki).

   - Add support for using an abstract scale for power units in the
     Energy Model (EM) and document it (Lukasz Luba).

   - Add em_cpu_energy() micro-optimization to the EM (Pavankumar
     Kondeti).

   - Modify the generic power domains (genpd) framwework to support
     suspend-to-idle (Ulf Hansson).

   - Fix creation of debugfs nodes in genpd (Thierry Strudel).

   - Clean up genpd (Lina Iyer).

   - Clean up the core system-wide suspend code and make it print driver
     flags for devices with debug enabled (Alex Shi, Patrice Chotard,
     Chen Yu).

   - Modify the ACPI system reboot code to make it prepare for system
     power off to avoid confusing the platform firmware (Kai-Heng Feng).

   - Update the pm-graph (multiple changes, mostly usability-related)
     and cpupower (online and offline CPU information support) PM
     utilities (Todd Brandt, Brahadambal Srinivasan)"

* tag 'pm-5.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (86 commits)
  cpufreq: Fix cpufreq_online() return value on errors
  cpufreq: Fix up several kerneldoc comments
  cpufreq: stats: Use local_clock() instead of jiffies
  cpufreq: schedutil: Simplify sugov_update_next_freq()
  cpufreq: intel_pstate: Simplify intel_cpufreq_update_pstate()
  PM: domains: create debugfs nodes when adding power domains
  opp: of: Allow empty opp-table with opp-shared
  dt-bindings: opp: Allow empty OPP tables
  media: venus: dev_pm_opp_put_*() accepts NULL argument
  drm/panfrost: dev_pm_opp_put_*() accepts NULL argument
  drm/lima: dev_pm_opp_put_*() accepts NULL argument
  PM / devfreq: exynos: dev_pm_opp_put_*() accepts NULL argument
  cpufreq: qcom-cpufreq-nvmem: dev_pm_opp_put_*() accepts NULL argument
  cpufreq: dt: dev_pm_opp_put_regulators() accepts NULL argument
  opp: Allow dev_pm_opp_put_*() APIs to accept NULL opp_table
  opp: Don't create an OPP table from dev_pm_opp_get_opp_table()
  cpufreq: dt: Don't (ab)use dev_pm_opp_get_opp_table() to create OPP table
  opp: Reduce the size of critical section in _opp_kref_release()
  PM / EM: Micro optimization in em_cpu_energy
  cpufreq: arm_scmi: Discover the power scale in performance protocol
  ...

This document seems to be out of date for many, many years. Even it has
misspelled from the first day.
ARCH_HASH_SCHED_TUNE should be ARCH_HAS_SCHED_TUNE
ARCH_HASH_SCHED_DOMAIN should be ARCH_HAS_SCHED_DOMAIN

Since v2.6.14, kernel completely deleted the relevant code and even
arch_init_sched_domains() was deleted.

Right now, kernel is asking architectures to call set_sched_topology() to
override the default sched domains.

On the other hand, to print the schedule debug information, users need to
set sched_debug cmdline or enable it by sysfs entry. So this patch also
adds the description for sched_debug.

Signed-off-by: Barry Song <song.bao.hua@hisilicon.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lkml.kernel.org/r/20201113115018.1628-1-song.bao.hua@hisilicon.com

The Energy Model (EM) can store power values in milli-Watts or in abstract
scale. This might cause issues in the subsystems which use the EM for
estimating the device power, such as:

 - mixing of different scales in a subsystem which uses multiple
   (cooling) devices (e.g. thermal Intelligent Power Allocation (IPA))

 - assuming that energy [milli-Joules] can be derived from the EM power
   values which might not be possible since the power scale doesn't have
   to be in milli-Watts

To avoid misconfiguration add the requisite documentation to the EM and
related subsystems: EAS and IPA.

Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The name of the directory where the schedule docs are
stored are wrong on those files.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Valentin Schneider <valentin.schneider@arm.com>
Link: https://lore.kernel.org/r/a32c2bba17aa69dc18670b7de1a3a35bfa1e1f88.1599660067.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/scheduler/sched-capacity.rst ought to be the canonical place
to blabber about SD_ASYM_CPUCAPACITY, so remove its explanation from
sched-energy.rst and point to sched-capacity.rst instead.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200731192016.7484-4-valentin.schneider@arm.com

Add some documentation detailing the concepts, requirements and
implementation of capacity aware scheduling across the different scheduler
classes.

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20200731192016.7484-3-valentin.schneider@arm.com

The documentation claims that two sched groups must not overlap. This is
no longer true, as overlapping sched groups are used on NUMA systems.
This change has been introduced by commit e3589f6c81e47 and was
documented by an in-code comment in commit 35a566e6e8a18.

Signed-off-by: Adrian Freund <adrian@freund.io>
Link: https://lore.kernel.org/r/20200407130525.76663-1-adrian@freund.io
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The rain.com domain recently moved to pdxhosts.com, making the scheduler
documentation point to broken links. Fix the links in the scheduler
documentation.

CC: Rick Lindsley <ricklind@linux.vnet.ibm.com>
Signed-off-by: Andre Azevedo <andre.azevedo@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

It has been observed, that highly-threaded, non-cpu-bound applications
running under cpu.cfs_quota_us constraints can hit a high percentage of
periods throttled while simultaneously not consuming the allocated
amount of quota. This use case is typical of user-interactive non-cpu
bound applications, such as those running in kubernetes or mesos when
run on multiple cpu cores.

This has been root caused to cpu-local run queue being allocated per cpu
bandwidth slices, and then not fully using that slice within the period.
At which point the slice and quota expires. This expiration of unused
slice results in applications not being able to utilize the quota for
which they are allocated.

The non-expiration of per-cpu slices was recently fixed by
'commit 512ac999d275 ("sched/fair: Fix bandwidth timer clock drift
condition")'. Prior to that it appears that this had been broken since
at least 'commit 51f2176d74ac ("sched/fair: Fix unlocked reads of some
cfs_b->quota/period")' which was introduced in v3.16-rc1 in 2014. That
added the following conditional which resulted in slices never being
expired.

if (cfs_rq->runtime_expires != cfs_b->runtime_expires) {
	/* extend local deadline, drift is bounded above by 2 ticks */
	cfs_rq->runtime_expires += TICK_NSEC;

Because this was broken for nearly 5 years, and has recently been fixed
and is now being noticed by many users running kubernetes
(https://github.com/kubernetes/kubernetes/issues/67577) it is my opinion
that the mechanisms around expiring runtime should be removed
altogether.

This allows quota already allocated to per-cpu run-queues to live longer
than the period boundary. This allows threads on runqueues that do not
use much CPU to continue to use their remaining slice over a longer
period of time than cpu.cfs_period_us. However, this helps prevent the
above condition of hitting throttling while also not fully utilizing
your cpu quota.

This theoretically allows a machine to use slightly more than its
allotted quota in some periods. This overflow would be bounded by the
remaining quota left on each per-cpu runqueueu. This is typically no
more than min_cfs_rq_runtime=1ms per cpu. For CPU bound tasks this will
change nothing, as they should theoretically fully utilize all of their
quota in each period. For user-interactive tasks as described above this
provides a much better user/application experience as their cpu
utilization will more closely match the amount they requested when they
hit throttling. This means that cpu limits no longer strictly apply per
period for non-cpu bound applications, but that they are still accurate
over longer timeframes.

This greatly improves performance of high-thread-count, non-cpu bound
applications with low cfs_quota_us allocation on high-core-count
machines. In the case of an artificial testcase (10ms/100ms of quota on
80 CPU machine), this commit resulted in almost 30x performance
improvement, while still maintaining correct cpu quota restrictions.
That testcase is available at https://github.com/indeedeng/fibtest.

Fixes: 512ac999d275 ("sched/fair: Fix bandwidth timer clock drift condition")
Signed-off-by: Dave Chiluk <chiluk+linux@indeed.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Phil Auld <pauld@redhat.com>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: John Hammond <jhammond@indeed.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Kyle Anderson <kwa@yelp.com>
Cc: Gabriel Munos <gmunoz@netflix.com>
Cc: Peter Oskolkov <posk@posk.io>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Brendan Gregg <bgregg@netflix.com>
Link: https://lkml.kernel.org/r/1563900266-19734-2-git-send-email-chiluk+linux@indeed.com

Pull rst conversion of docs from Mauro Carvalho Chehab:
 "As agreed with Jon, I'm sending this big series directly to you, c/c
  him, as this series required a special care, in order to avoid
  conflicts with other trees"

* tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (77 commits)
  docs: kbuild: fix build with pdf and fix some minor issues
  docs: block: fix pdf output
  docs: arm: fix a breakage with pdf output
  docs: don't use nested tables
  docs: gpio: add sysfs interface to the admin-guide
  docs: locking: add it to the main index
  docs: add some directories to the main documentation index
  docs: add SPDX tags to new index files
  docs: add a memory-devices subdir to driver-api
  docs: phy: place documentation under driver-api
  docs: serial: move it to the driver-api
  docs: driver-api: add remaining converted dirs to it
  docs: driver-api: add xilinx driver API documentation
  docs: driver-api: add a series of orphaned documents
  docs: admin-guide: add a series of orphaned documents
  docs: cgroup-v1: add it to the admin-guide book
  docs: aoe: add it to the driver-api book
  docs: add some documentation dirs to the driver-api book
  docs: driver-model: move it to the driver-api book
  docs: lp855x-driver.rst: add it to the driver-api book
  ...