cpufreq: userspace: Move is_managed indicator into per-policy structure

The userspace governor uses the 'cpu' field of cpufreq_policy structure
to track if it is allowed to set the speed of the poli

cpufreq: userspace: Move is_managed indicator into per-policy structure

The userspace governor uses the 'cpu' field of cpufreq_policy structure
to track if it is allowed to set the speed of the policy.

However, there is a window where the 'cpu' field is equal to the value
of nr_cpus_id when all affected CPUs of policy are offline, which is an
illegal value to get the per-CPU variable.

To avoid this issue, modify the governor to use a per-policy indicator
to track if the policy is managed.

Signed-off-by: Liao Chang <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: userspace: Use fine-grained mutex in userspace governor

The userspace governor currently uses a big global mutex to avoid the
race condition on the governor_data field of cpufreq_policy str

cpufreq: userspace: Use fine-grained mutex in userspace governor

The userspace governor currently uses a big global mutex to avoid the
race condition on the governor_data field of cpufreq_policy structure.

This leads to a low concurrency if multiple userspace applications are
trying to set the speed of different policies at the same time.

Introduce a per-policy mutex to allow the updating of different policies
to be performed concurrently, improving overall concurrency.

Signed-off-by: Liao Chang <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Register governors at core_initcall

Currently, most CPUFreq governors are registered at the core_initcall
time when the given governor is the default one, and the module_init
time otherwise

cpufreq: Register governors at core_initcall

Currently, most CPUFreq governors are registered at the core_initcall
time when the given governor is the default one, and the module_init
time otherwise.

In preparation for letting users specify the default governor on the
kernel command line, change all of them to be registered at the
core_initcall unconditionally, as it is already the case for the
schedutil and performance governors. This will allow us to assume
that builtin governors have been registered before the built-in
CPUFreq drivers probe.

And since all governors have similar init/exit patterns now, introduce
two new macros, cpufreq_governor_{init,exit}(), to factorize the code.

Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Quentin Perret <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Initialize the governors in core_initcall

Initialize the cpufreq governors earlier to allow for earlier
performance control during the boot process.

Signed-off-by: Amit Kucheria <amit.kuch

cpufreq: Initialize the governors in core_initcall

Initialize the cpufreq governors earlier to allow for earlier
performance control during the boot process.

Signed-off-by: Amit Kucheria <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Reviewed-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Daniel Lezcano <[email protected]>
Link: https://lore.kernel.org/r/b98eae9b44eb2f034d7f5d12a161f5f831be1eb7.1571656015.git.amit.kucheria@linaro.org

show more ...

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of th

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500

Based on 2 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 4122 file(s).

Signed-off-by: Thomas Gleixner <[email protected]>
Reviewed-by: Enrico Weigelt <[email protected]>
Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Allison Randal <[email protected]>
Cc: [email protected]
Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

cpufreq: governor: Get rid of governor events

The design of the cpufreq governor API is not very straightforward,
as struct cpufreq_governor provides only one callback to be invoked
from different c

cpufreq: governor: Get rid of governor events

The design of the cpufreq governor API is not very straightforward,
as struct cpufreq_governor provides only one callback to be invoked
from different code paths for different purposes. The purpose it is
invoked for is determined by its second "event" argument, causing it
to act as a "callback multiplexer" of sorts.

Unfortunately, that leads to extra complexity in governors, some of
which implement the ->governor() callback as a switch statement
that simply checks the event argument and invokes a separate function
to handle that specific event.

That extra complexity can be eliminated by replacing the all-purpose
->governor() callback with a family of callbacks to carry out specific
governor operations: initialization and exit, start and stop and policy
limits updates. That also turns out to reduce the code size too, so
do it.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Viresh Kumar <[email protected]>

show more ...

cpufreq: Fix GOV_LIMITS handling for the userspace governor

Currently, the userspace governor only updates frequency on GOV_LIMITS
if policy->cur falls outside policy->{min/max}. However, it is also

cpufreq: Fix GOV_LIMITS handling for the userspace governor

Currently, the userspace governor only updates frequency on GOV_LIMITS
if policy->cur falls outside policy->{min/max}. However, it is also
necessary to update current frequency on GOV_LIMITS to match the user
requested value if it can be achieved within the new policy->{max/min}.

This was previously the behaviour in the governor until commit d1922f0
("cpufreq: Simplify userspace governor") which incorrectly assumed that
policy->cur == user requested frequency via scaling_setspeed. This won't
be true if the user requested frequency falls outside policy->{min/max}.
Ex: a temporary thermal cap throttled the user requested frequency.

Fix this by storing the user requested frequency in a seperate variable.
The governor will then try to achieve this request on every GOV_LIMITS
change.

Fixes: d1922f02562f (cpufreq: Simplify userspace governor)
Signed-off-by: Sai Gurrappadi <[email protected]>
Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Clean up default and fallback governor setup

The preprocessor magic used for setting the default cpufreq governor
(and for using the performance governor as a fallback one for that
matter)

cpufreq: Clean up default and fallback governor setup

The preprocessor magic used for setting the default cpufreq governor
(and for using the performance governor as a fallback one for that
matter) is really nasty, so replace it with __weak functions and
overrides.

Signed-off-by: Rafael J. Wysocki <[email protected]>
Acked-by: Saravana Kannan <[email protected]>
Acked-by: Viresh Kumar <[email protected]>

show more ...

cpufreq / governor: Remove fossil comment

cpufreq_set_policy() has been changed to origin __cpufreq_set_policy()
and policy->lock has been converted to rewrite lock by commit 5a01f2.
So remove the c

cpufreq / governor: Remove fossil comment

cpufreq_set_policy() has been changed to origin __cpufreq_set_policy()
and policy->lock has been converted to rewrite lock by commit 5a01f2.
So remove the comment.

Acked-by: Viresh Kumar <[email protected]>
Signed-off-by: Lan Tianyu <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Fix minor formatting issues

There were a few noticeable formatting issues in core cpufreq code.
This cleans them up to make code look better. The changes include:
- Whitespace cleanup.
-

cpufreq: Fix minor formatting issues

There were a few noticeable formatting issues in core cpufreq code.
This cleans them up to make code look better. The changes include:
- Whitespace cleanup.
- Rearrangements of code.
- Multiline comments fixes.
- Formatting changes to fit 80 columns.

Copyright information in cpufreq.c is also updated to include my name
for 2013.

[rjw: Changelog]
Signed-off-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Simplify userspace governor

Userspace governor has got more code than what it needs for its
functioning, so simplify it.

Portions of code removed are:
- Extra header files which aren't re

cpufreq: Simplify userspace governor

Userspace governor has got more code than what it needs for its
functioning, so simplify it.

Portions of code removed are:
- Extra header files which aren't required anymore (rearrange them
as well).
- cpu_{max|min|cur|set}_freq, as they are always the same as
policy->{max|min|cur}.
- userspace_cpufreq_notifier_block as we don't need to set
cpu_cur_freq anymore.
- cpus_using_userspace_governor as it was for the notifier code.

Signed-off-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Don't check cpu_online(policy->cpu)

policy->cpu or cpus in policy->cpus can't be offline anymore. And so we don't
need to check if they are online or not.

Signed-off-by: Viresh Kumar <vire

cpufreq: Don't check cpu_online(policy->cpu)

policy->cpu or cpus in policy->cpus can't be offline anymore. And so we don't
need to check if they are online or not.

Signed-off-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

cpufreq: Improve debug prints

With debug options on, it is difficult to locate cpufreq core's debug prints.
Fix this by prefixing debug prints with KBUILD_MODNAME.

Signed-off-by: Viresh Kumar <vire

cpufreq: Improve debug prints

With debug options on, it is difficult to locate cpufreq core's debug prints.
Fix this by prefixing debug prints with KBUILD_MODNAME.

Signed-off-by: Viresh Kumar <[email protected]>
Signed-off-by: Rafael J. Wysocki <[email protected]>

show more ...

[CPUFREQ] cpufreq:userspace: fix cpu_cur_freq updation

CPU frequency is guranteed to be changed on notifier callback with
CPUFREQ_POSTCHANGE. Notifier callback with CPUFREQ_PRECHANGE does
not gurant

[CPUFREQ] cpufreq:userspace: fix cpu_cur_freq updation

CPU frequency is guranteed to be changed on notifier callback with
CPUFREQ_POSTCHANGE. Notifier callback with CPUFREQ_PRECHANGE does
not gurantee a change in frequency; after it, if cpufreq driver is
unable to change CPU to new frequency. This results in wrong
information being fed to user (if setting CPU frequency fails)
upon doing like,

cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed

Hence in userspace governer update cpu_cur_freq only if notifier
has been called with POSTCHANGE.

Signed-off-by: Afzal Mohammed <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

show more ...

[CPUFREQ] use dynamic debug instead of custom infrastructure

With dynamic debug having gained the capability to report debug messages
also during the boot process, it offers a far superior interface

[CPUFREQ] use dynamic debug instead of custom infrastructure

With dynamic debug having gained the capability to report debug messages
also during the boot process, it offers a far superior interface for
debug messages than the custom cpufreq infrastructure. As a first step,
remove the old cpufreq_debug_printk() function and replace it with a call
to the generic pr_debug() function.

How can dynamic debug be used on cpufreq? You need a kernel which has
CONFIG_DYNAMIC_DEBUG enabled.

To enabled debugging during runtime, mount debugfs and

$ echo -n 'module cpufreq +p' > /sys/kernel/debug/dynamic_debug/control

for debugging the complete "cpufreq" module. To achieve the same goal during
boot, append

ddebug_query="module cpufreq +p"

as a boot parameter to the kernel of your choice.

For more detailled instructions, please see
Documentation/dynamic-debug-howto.txt

Signed-off-by: Dominik Brodowski <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

show more ...

[CPUFREQ] checkpatch cleanups for userspace governor

Signed-off-by: Dave Jones <[email protected]>

[CPUFREQ] Don't export governors for default governor

We don't need to export the governors for use as the default governor,
because the default governor will be built-in anyway and we can access
th

[CPUFREQ] Don't export governors for default governor

We don't need to export the governors for use as the default governor,
because the default governor will be built-in anyway and we can access
the symbol directly.

This also fixes the following sparse warnings:

drivers/cpufreq/cpufreq_conservative.c:578:25: warning: symbol 'cpufreq_gov_conservative' was not declared. Should it be static?
drivers/cpufreq/cpufreq_ondemand.c:582:25: warning: symbol 'cpufreq_gov_ondemand' was not declared. Should it be static?
drivers/cpufreq/cpufreq_performance.c:39:25: warning: symbol 'cpufreq_gov_performance' was not declared. Should it be static?
drivers/cpufreq/cpufreq_powersave.c:38:25: warning: symbol 'cpufreq_gov_powersave' was not declared. Should it be static?
drivers/cpufreq/cpufreq_userspace.c:190:25: warning: symbol 'cpufreq_gov_userspace' was not declared. Should it be static?

Signed-off-by: Sven Wegener <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

show more ...

NR_CPUS: Replace NR_CPUS in cpufreq userspace routines

* Replace arrays sized by NR_CPUS with percpu variables.

Prior reference: http://marc.info/?l=linux-kernel&m=120251421825989&w=4
Sub

NR_CPUS: Replace NR_CPUS in cpufreq userspace routines

* Replace arrays sized by NR_CPUS with percpu variables.

Prior reference: http://marc.info/?l=linux-kernel&m=120251421825989&w=4
Subject: [PATCH 1/4] cpufreq: change cpu freq tables to per_cpu variables
From: Mike Travis <travis () sgi ! com>
Date: 2008-02-08 23:37:39

Signed-off-by: Mike Travis <[email protected]>
Signed-off-by: Ingo Molnar <[email protected]>

show more ...

[CPUFREQ] Eliminate cpufreq_userspace scaling_setspeed deadlock

Eliminate cpufreq_userspace scaling_setspeed deadlock.

Luming Yu recently uncovered yet another cpufreq related deadlock.
One thread

[CPUFREQ] Eliminate cpufreq_userspace scaling_setspeed deadlock

Eliminate cpufreq_userspace scaling_setspeed deadlock.

Luming Yu recently uncovered yet another cpufreq related deadlock.
One thread that continuously switches the governors and the other thread that
repeatedly cats the contents of cpufreq directory causes both these threads to
go into a deadlock.

Detailed examination of the deadlock showed the exact flow before the deadlock
as:

Thread 1 Thread 2
________ ________
cats files under /sys/devices/.../cpufreq/
Set governor to userspace
Adds a new sysfs entry for
scaling_setspeed
cats files under /sys/devices/.../cpufreq/

Set governor to performance
Holds cpufreq_rw_sem in write
mode
Sends a STOP notify to
userspace governor
cat /sys/devices/.../cpufreq/scaling_setspeed
Gets a handle on the above sysfs entry with
sysfs_get_active
Blocks while trying to get cpufreq_rw_sem
in read mode
Remove a sysfs entry for
scaling_setspeed
Blocks on sysfs_deactivate
while waiting for earlier
get_active (on other thread)
to drain

At this point both threads go into deadlock and any other thread that tries to
do anything with sysfs cpufreq will also block.

There seems to be no easy way to avoid this deadlock as long as
cpufreq_userspace adds/removes the sysfs entry under same kobject as cpufreq.
Below patch moves scaling_setspeed to cpufreq.c, keeping it always and calling
back the governor on read/write. This is the cleanest fix I could think of,
even though adding two callbacks in governor structure just for this seems
unnecessary.

Note that the change makes scaling_setspeed under /sys/.../cpufreq permanent
and returns <unsupported> when governor is not userspace.

Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

show more ...

cpufreq: Initialise default governor before use

When the cpufreq driver starts up at boot time, it calls into the default
governor which might not be initialised yet. This hurts when the
governor's

cpufreq: Initialise default governor before use

When the cpufreq driver starts up at boot time, it calls into the default
governor which might not be initialised yet. This hurts when the
governor's worker function relies on memory that is not yet set up by its
init function.

This migrates all governors from module_init() to fs_initcall() when being
the default, as was already done in cpufreq_performance when it was the
only possible choice. The performance governor is always initialized early
because it might be used as fallback even when not being the default.

Fixes at least one actual oops where ondemand is the default governor and
cpufreq_governor_dbs() uses the uninitialised kondemand_wq work-queue
during boot-time.

Signed-off-by: Johannes Weiner <[email protected]>
Cc: Dave Jones <[email protected]>
Cc: "Rafael J. Wysocki" <[email protected]>
Cc: Venkatesh Pallipadi <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...

sysfs: kill unnecessary attribute->owner

sysfs is now completely out of driver/module lifetime game. After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason

sysfs: kill unnecessary attribute->owner

sysfs is now completely out of driver/module lifetime game. After
deletion, a sysfs node doesn't access anything outside sysfs proper,
so there's no reason to hold onto the attribute owners. Note that
often the wrong modules were accounted for as owners leading to
accessing removed modules.

This patch kills now unnecessary attribute->owner. Note that with
this change, userland holding a sysfs node does not prevent the
backing module from being unloaded.

For more info regarding lifetime rule cleanup, please read the
following message.

http://article.gmane.org/gmane.linux.kernel/510293

(tweaked by Greg to not delete the field just yet, to make it easier to
merge things properly.)

Signed-off-by: Tejun Heo <[email protected]>
Cc: Cornelia Huck <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

show more ...

[CPUFREQ] Keep userspace governor quiet when it is not being used

Userspace governor registers a frequency change notifier at init time, even
when no CPU is set to userspace governor. Make it regist

[CPUFREQ] Keep userspace governor quiet when it is not being used

Userspace governor registers a frequency change notifier at init time, even
when no CPU is set to userspace governor. Make it register only when
atleast one CPU is using userspace.

Signed-off-by: Venkatesh Pallipadi <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

show more ...

[CPUFREQ] Remove hotplug cpu crap

The hotplug CPU locking in cpufreq is horrendous. No-one seems to care
enough to fix it, so just remove it so that the 99.9% of the real world
users of this code c

[CPUFREQ] Remove hotplug cpu crap

The hotplug CPU locking in cpufreq is horrendous. No-one seems to care
enough to fix it, so just remove it so that the 99.9% of the real world
users of this code can use cpufreq without being bothered by warnings.

Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

show more ...

[CPUFREQ] handle sysfs errors

Signed-off-by: Jeff Garzik <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Dave Jones <[email protected]>

[PATCH] Reorganize the cpufreq cpu hotplug locking to not be totally bizare

The patch below moves the cpu hotplugging higher up in the cpufreq
layering; this is needed to avoid recursive taking of t

[PATCH] Reorganize the cpufreq cpu hotplug locking to not be totally bizare

The patch below moves the cpu hotplugging higher up in the cpufreq
layering; this is needed to avoid recursive taking of the cpu hotplug
lock and to otherwise detangle the mess.

The new rules are:
1. you must do lock_cpu_hotplug() around the following functions:
__cpufreq_driver_target
__cpufreq_governor (for CPUFREQ_GOV_LIMITS operation only)
__cpufreq_set_policy
2. governer methods (.governer) must NOT take the lock_cpu_hotplug()
lock in any way; they are called with the lock taken already
3. if your governer spawns a thread that does things, like calling
__cpufreq_driver_target, your thread must honor rule #1.
4. the policy lock and other cpufreq internal locks nest within
the lock_cpu_hotplug() lock.

I'm not entirely happy about how the __cpufreq_governor rule ended up
(conditional locking rule depending on the argument) but basically all
callers pass this as a constant so it's not too horrible.

The patch also removes the cpufreq_governor() function since during the
locking audit it turned out to be entirely unused (so no need to fix it)

The patch works on my testbox, but it could use more testing
(otoh... it can't be much worse than the current code)

Signed-off-by: Arjan van de Ven <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

show more ...