Currently, cpufreq_remove_dev() invokes the ->exit() driver callback
without holding the policy rwsem which is inconsistent with what
happens if ->exit() is invoked directly from cpufreq_offline().
It also manipulates the real_cpus mask and removes the CPU device
symlink without holding the policy rwsem, but cpufreq_offline() holds
the rwsem around the modifications thereof.
For consistency, modify cpufreq_remove_dev() to hold the policy rwsem
until the ->exit() callback has been called (or it has been determined
that it is not necessary to call it).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Split the "core" part running under the policy rwsem out of
cpufreq_offline() to allow the locking in cpufreq_remove_dev() to be
rearranged more easily.
As a side-effect this eliminates the unlock label that's not needed
any more.
No expected functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Notice that cpufreq_offline() only needs to check policy_is_inactive()
once and rearrange the code in there to make that happen.
No expected functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
add_cpu_dev_symlink() is responsible for setting the CPUs in the
real_cpus mask, the reverse of which should be done from
remove_cpu_dev_symlink() to make it look clean and avoid any breakage
later on.
Move the call to clear the mask to remove_cpu_dev_symlink().
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This reverts commit f346e96267.
The commit tried to fix a possible real bug but it made it even worse.
The fix was simply buggy as now an error out to out_offline_policy or
out_exit_policy will try to release a semaphore which was never taken in
the first place. This works fine only if we failed late, i.e. via
out_destroy_policy.
Fixes: f346e96267 ("cpufreq: Fix possible race in cpufreq online error path")
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For some platforms, the frequency returned by hardware may be slightly
different from what is provided in the frequency table. For example,
hardware may return 499 MHz instead of 500 MHz. In such cases it is
better to avoid getting into unnecessary frequency updates, as we may
end up switching policy->cur between the two and sending unnecessary
pre/post update notifications, etc.
This patch has chosen allows the hardware frequency and table frequency
to deviate by 1 MHz for now, we may want to increase it a bit later on
if someone still complains.
Reported-by: Rex-BC Chen <rex-bc.chen@mediatek.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Jia-wei Chang <jia-wei.chang@mediatek.com>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When cpufreq online fails, the policy->cpus mask is not cleared and
policy->rwsem is released too early, so the driver can be invoked
via the cpuinfo_cur_freq sysfs attribute while its ->offline() or
->exit() callbacks are being run.
Take policy->clk as an example:
static int cpufreq_online(unsigned int cpu)
{
...
// policy->cpus != 0 at this time
down_write(&policy->rwsem);
ret = cpufreq_add_dev_interface(policy);
up_write(&policy->rwsem);
return 0;
out_destroy_policy:
for_each_cpu(j, policy->real_cpus)
remove_cpu_dev_symlink(policy, get_cpu_device(j));
up_write(&policy->rwsem);
...
out_exit_policy:
if (cpufreq_driver->exit)
cpufreq_driver->exit(policy);
clk_put(policy->clk);
// policy->clk is a wild pointer
...
^
|
Another process access
__cpufreq_get
cpufreq_verify_current_freq
cpufreq_generic_get
// acces wild pointer of policy->clk;
|
|
out_offline_policy: |
cpufreq_policy_free(policy); |
// deleted here, and will wait for no body reference
cpufreq_policy_put_kobj(policy);
}
Address this by modifying cpufreq_online() to release policy->rwsem
in the error path after the driver callbacks have run and to clear
policy->cpus before releasing the semaphore.
Fixes: 7106e02bae ("cpufreq: release policy->rwsem on error")
Signed-off-by: Schspa Shi <schspa@gmail.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This effectively revert '4bf8e582119e ("cpufreq: Remove ready()
callback")', in order to reintroduce the ready callback.
This is needed in order to be able to leave the thermal pressure
interrupts in the Qualcomm CPUfreq driver disabled during
initialization, so that it doesn't fire while related_cpus are still 0.
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
[ Viresh: Added the Chinese translation as well and updated commit msg ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
There are currently 2 ways to create a set of sysfs files for a
kobj_type, through the default_attrs field, and the default_groups
field. Move the cpufreq code to use default_groups field which has been
the preferred way since aa30f47cf6 ("kobject: Add support for default
attribute groups to kobj_type") so that we can soon get rid of the
obsolete default_attrs field.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The min and max frequency QoS requests in the cpufreq core are
initialized to whatever the current min and max frequency values are
at the init time, but if any of these values change later (for
example, cpuinfo.max_freq is updated by the driver), these initial
request values will be limiting the CPU frequency unnecessarily
unless they are changed by user space via sysfs.
To address this, initialize min_freq_req and max_freq_req to
FREQ_QOS_MIN_DEFAULT_VALUE and FREQ_QOS_MAX_DEFAULT_VALUE,
respectively, so they don't really limit anything until user
space updates them.
Reported-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Tested-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Make the comment in blocking_notifier_call_chain() easier to
understand.
Signed-off-by: Tang Yizhou <tangyizhou@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When I hot added a CPU, I found 'cpufreq' directory was not created
below /sys/devices/system/cpu/cpuX/.
It is because get_cpu_device() failed in add_cpu_dev_symlink().
cpufreq_add_dev() is the .add_dev callback of a CPU subsys interface.
It will be called when the CPU device registered into the system.
The call chain is as follows:
register_cpu()
->device_register()
->device_add()
->bus_probe_device()
->cpufreq_add_dev()
But only after the CPU device has been registered, we can get the
CPU device by get_cpu_device(), otherwise it will return NULL.
Since we already have the CPU device in cpufreq_add_dev(), pass
it to add_cpu_dev_symlink().
I noticed that the 'kobj' of the CPU device has been added into
the system before cpufreq_add_dev().
Fixes: 2f0ba790df ("cpufreq: Fix creation of symbolic links to policy directories")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Let the governors schedutil, conservative and ondemand to work, if possible
on efficient frequencies only.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This newly introduced flag can be applied by a governor to a CPUFreq
relation, when looking for a frequency within the policy table. The
resolution would then only walk through efficient frequencies.
Even with the flag set, the policy max limit will still be honoured. If no
efficient frequencies can be found within the limits of the policy, an
inefficient one would be returned.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When applying the policy min/max limits, the requested frequency is
simply clamped to not be out of range. It means, however, if one of the
boundaries isn't an available frequency, the frequency resolution can
return a value out of those limits, depending on the relation used.
e.g. freq{0,1,2} being available frequencies.
freq0 policy->min freq1 policy->max freq2
| | | | |
17kHz 18kHz 19kHz 20kHz 21kHz
__resolve_freq(21kHz, CPUFREQ_RELATION_L) -> 21kHz (out of bounds)
__resolve_freq(17kHz, CPUFREQ_RELATION_H) -> 17kHz (out of bounds)
If, during the policy init, we resolve the requested min/max to existing
frequencies, we ensure that any CPUFREQ_RELATION_* would resolve to a
frequency which is inside the policy min/max range.
Making the policy limits rigid helps to introduce the inefficient
frequencies support. Resolving an inefficient frequency to an efficient
one should not transgress policy->max (which can be set for thermal
reason) and having a value we can trust simplify this comparison.
Signed-off-by: Vincent Donnefort <vincent.donnefort@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This isn't used anymore, get rid of it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Pull ARM cpufreq driver changes for v5.15 from Viresh Kumar:
"This contains:
- Update cpufreq-dt blocklist with more platforms (Bjorn Andersson).
- Allow freq changes from any CPU for qcom-hw driver (Taniya Das).
- Add DSVS interrupt's support for qcom-hw driver (Thara Gopinath).
- A new callback (->register_em()) to register EM at a more convenient
point of time."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: qcom-hw: Set dvfs_possible_from_any_cpu cpufreq driver flag
cpufreq: blocklist more Qualcomm platforms in cpufreq-dt-platdev
cpufreq: qcom-cpufreq-hw: Add dcvs interrupt support
cpufreq: scmi: Use .register_em() to register with energy model
cpufreq: vexpress: Use .register_em() to register with energy model
cpufreq: scpi: Use .register_em() to register with energy model
cpufreq: qcom-cpufreq-hw: Use .register_em() to register with energy model
cpufreq: omap: Use .register_em() to register with energy model
cpufreq: mediatek: Use .register_em() to register with energy model
cpufreq: imx6q: Use .register_em() to register with energy model
cpufreq: dt: Use .register_em() to register with energy model
cpufreq: Add callback to register with energy model
cpufreq: vexpress: Set CPUFREQ_IS_COOLING_DEV flag
Many cpufreq drivers register with the energy model for each policy and
do exactly the same thing. Follow the footsteps of thermal-cooling, to
get it done from the cpufreq core itself.
Provide a new callback, which will be called, if present, by the cpufreq
core at the right moment (more on that in the code's comment). Also
provide a generic implementation that uses dev_pm_opp_of_register_em().
This also allows us to register with the EM at a later point of time,
compared to ->init(), from where the EM core can access cpufreq policy
directly using cpufreq_cpu_get() type of helpers and perform other work,
like marking few frequencies inefficient, this will be done separately.
Reviewed-by: Quentin Perret <qperret@google.com>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().
Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Commit e3c0623608 ("cpufreq: add cpufreq_driver_resolve_freq()")
introduced this callback, back in 2016, for drivers that provide the
->target() callback.
The kernel hasn't seen a single user of it in the past 5 years and
it is not likely to be used any time soon.
Remove it for now.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
__cpufreq_driver_target() open codes cpufreq_driver_resolve_freq(), lets
make the former reuse the later.
Separate out __resolve_freq() to accept relation as well as an argument
and use it at both the locations.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Now that all users of ->stop_cpu() have been migrated to using other
callbacks, drop it from the core.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Minor edits in the subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In the CPU removal path the ->offline() callback provided by the
driver is always invoked before ->exit(), but in the cpufreq_online()
error path it is not, so ->exit() is expected to somehow know the
context in which it has been called and act accordingly.
That is less than straightforward, so make cpufreq_online() invoke
the driver's ->offline() callback, if present, on errors before
->exit() too.
This only potentially affects intel_pstate.
Fixes: 91a12e91dc ("cpufreq: Allow light-weight tear down and bring up of CPUs")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Macro 'for_each_policy' has become unused since commit
f963735a3c ("cpufreq: Create for_each_{in}active_policy()"), so
remove it.
Signed-off-by: Shaokun Zhang <zhangshaokun@hisilicon.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Change 'Terget' to 'Target'.
Should be Target.
Signed-off-by: Yue Hu <huyue2@yulong.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
During cpufreq driver's registration, if the ->init() callback for all
the CPUs fail then there is not much point in keeping the driver around
as it will only account for more of unnecessary noise, for example
cpufreq core will try to suspend/resume the driver which never got
registered properly.
The removal of such a driver is avoided if the driver carries the
CPUFREQ_STICKY flag. This was added way back [1] in 2004 and perhaps no
one should ever need it now. A lot of drivers do set this flag, probably
because they just copied it from other drivers.
This was added earlier for some platforms [2] because their cpufreq
drivers were getting registered before the CPUs were registered with
subsys framework. And hence they used to fail.
The same isn't true anymore though. The current code flow in the kernel
is:
start_kernel()
-> kernel_init()
-> kernel_init_freeable()
-> do_basic_setup()
-> driver_init()
-> cpu_dev_init()
-> subsys_system_register() //For CPUs
-> do_initcalls()
-> cpufreq_register_driver()
Clearly, the CPUs will always get registered with subsys framework
before any cpufreq driver can get probed. Remove the flag and update the
relevant drivers.
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/include/linux/cpufreq.h?id=7cc9f0d9a1ab04cedc60d64fd8dcf7df224a3b4d # [1]
Link: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/arch/arm/mach-sa1100/cpu-sa1100.c?id=f59d3bbe35f6268d729f51be82af8325d62f20f5 # [2]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
First off, some cpufreq drivers (eg. intel_pstate) can pass hints
beyond the current target frequency to the hardware and there are no
provisions for doing that in the cpufreq framework. In particular,
today the driver has to assume that it should not allow the frequency
to fall below the one requested by the governor (or the required
capacity may not be provided) which may not be the case and which may
lead to excessive energy usage in some scenarios.
Second, the hints passed by these drivers to the hardware need not be
in terms of the frequency, so representing the utilization numbers
coming from the scheduler as frequency before passing them to those
drivers is not really useful.
Address the two points above by adding a special-purpose replacement
for the ->fast_switch callback, called ->adjust_perf, allowing the
governor to pass abstract performance level (rather than frequency)
values for the minimum (required) and target (desired) performance
along with the CPU capacity to compare them to.
Also update the schedutil governor to use the new callback instead
of ->fast_switch if present and if the utilization mertics are
frequency-invariant (that is requisite for the direct mapping
between the utilization and the CPU performance levels to be a
reasonable approximation).
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Make cpufreq_online() return negative error codes on all errors that
cause the policy to be destroyed, as appropriate.
Signed-off-by: Wang ShaoBo <bobo.shaobowang@huawei.com>
[ rjw: Subject and changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix up the remaining kerneldoc comments that don't adhere to the
expected format and clarify some of them a bit.
No functional changes.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Add a new field to be set when the CPUFREQ_GOV_STRICT_TARGET flag is
set for the current governor to struct cpufreq_policy, so that the
drivers needing to check CPUFREQ_GOV_STRICT_TARGET do not have to
access the governor object during every frequency transition.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
A new cpufreq governor flag will be added subsequently, so replace
the bool dynamic_switching fleid in struct cpufreq_governor with a
flags field and introduce CPUFREQ_GOV_DYNAMIC_SWITCHING to set for
the "dynamic switching" governors instead of it.
No intentional functional impact.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
The restore_freq field in struct cpufreq_policy is only used by
__target_index() in one place and a local variable in that function
may as well be used instead of it, so drop it and modify
__target_index() accordingly.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Add a helper function to test the flags of the cpufreq driver in use
againt a given flags mask.
In particular, this will be needed to test the
CPUFREQ_NEED_UPDATE_LIMITS cpufreq driver flag in the schedutil
governor.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Generally, a cpufreq driver may need to update some internal upper
and lower frequency boundaries on policy max and min changes,
respectively, but currently this does not work if the target
frequency does not change along with the policy limit.
Namely, if the target frequency does not change along with the
policy min or max, the "target_freq == policy->cur" check in
__cpufreq_driver_target() prevents driver callbacks from being
invoked and they do not even have a chance to update the
corresponding internal boundary.
This particularly affects the "powersave" and "performance"
governors that always set the target frequency to one of the
policy limits and it never changes when the other limit is updated.
To allow cpufreq the drivers needing to update internal frequency
boundaries on policy limits changes to avoid this issue, introduce
a new driver flag, CPUFREQ_NEED_UPDATE_LIMITS, that (when set) will
neutralize the check mentioned above.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
The cpufreq core checks if the frequency programmed by the bootloaders
is not listed in the freq table and programs one from the table in such
a case. This is done only if the driver has set the
CPUFREQ_NEED_INITIAL_FREQ_CHECK flag.
Currently we print two separate messages, with almost the same content,
and do this with a pr_warn() which may be a bit too much as the driver
only asked us to check this as it expected this to be the case. Lower
down the severity of the print message by switching to pr_info() instead
and print a single message only.
Reported-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sumit Gupta <sumitg@nvidia.com>
Tested-by: Sumit Gupta <sumitg@nvidia.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Compared to other arch_* functions, arch_set_freq_scale() has an atypical
weak definition that can be replaced by a strong architecture specific
implementation.
The more typical support for architectural functions involves defining
an empty stub in a header file if the symbol is not already defined in
architecture code. Some examples involve:
- #define arch_scale_freq_capacity topology_get_freq_scale
- #define arch_scale_freq_invariant topology_scale_freq_invariant
- #define arch_scale_cpu_capacity topology_get_cpu_scale
- #define arch_update_cpu_topology topology_update_cpu_topology
- #define arch_scale_thermal_pressure topology_get_thermal_pressure
- #define arch_set_thermal_pressure topology_set_thermal_pressure
Bring arch_set_freq_scale() in line with these functions by renaming it to
topology_set_freq_scale() in the arch topology driver, and by defining the
arch_set_freq_scale symbol to point to the new function for arm and arm64.
While there are other users of the arch_topology driver, this patch defines
arch_set_freq_scale for arm and arm64 only, due to their existing
definitions of arch_scale_freq_capacity. This is the getter function of the
frequency invariance scale factor and without a getter function, the
setter function - arch_set_freq_scale() has not purpose.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Sudeep Holla <sudeep.holla@arm.com> (BL_SWITCHER and topology parts)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The cpufreq core handles the updates to policy->cur and recording of
cpufreq trace events for all the governors except schedutil's fast
switch case.
Move that as well to cpufreq core for consistency and readability.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Now that all the blockers are gone for enabling stats in fast-switching
case, enable it.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The passed cpumask arguments to arch_set_freq_scale() and
arch_freq_counters_available() are only iterated over, so reflect this
in the prototype. This also allows to pass system cpumasks like
cpu_online_mask without getting a warning.
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Now that the update of the FI scale factor is done in cpufreq core for
selected functions - target(), target_index() and fast_switch(),
we can provide feedback to the task scheduler and architecture code
on whether cpufreq supports FI.
For this purpose provide an external function to expose whether the
cpufreq drivers support FI, by using a static key.
The logic behind the enablement of cpufreq-based invariance is as
follows:
- cpufreq-based invariance is disabled by default
- cpufreq-based invariance is enabled if any of the callbacks
above is implemented while the unsupported setpolicy() is not
The cpufreq_supports_freq_invariance() function only returns whether
cpufreq is instrumented with the arch_set_freq_scale() calls that
result in support for frequency invariance. Due to the lack of knowledge
on whether the implementation of arch_set_freq_scale() actually results
in the setting of a scale factor based on cpufreq information, it is up
to the architecture code to ensure the setting and provision of the
scale factor to the scheduler.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
To properly scale its per-entity load-tracking signals, the task scheduler
needs to be given a frequency scale factor, i.e. some image of the current
frequency the CPU is running at. Currently, this scale can be computed
either by using counters (APERF/MPERF on x86, AMU on arm64), or by
piggy-backing on the frequency selection done by cpufreq.
For the latter, drivers have to explicitly set the scale factor
themselves, despite it being purely boiler-plate code: the required
information depends entirely on the kind of frequency switch callback
implemented by the driver, i.e. either of: target_index(), target(),
fast_switch() and setpolicy().
The fitness of those callbacks with regard to driving the Frequency
Invariance Engine (FIE) is studied below:
target_index()
==============
Documentation states that the chosen frequency "must be determined by
freq_table[index].frequency". It isn't clear if it *has* to be that
frequency, or if it can use that frequency value to do some computation
that ultimately leads to a different frequency selection. All drivers
go for the former, while the vexpress-spc-cpufreq has an atypical
implementation which is handled separately.
Therefore, the hook works on the assumption the core can use
freq_table[index].frequency.
target()
=======
This has been flagged as deprecated since:
commit 9c0ebcf78f ("cpufreq: Implement light weight ->target_index() routine")
It also doesn't have that many users:
gx-suspmod.c:439: .target = cpufreq_gx_target,
s3c24xx-cpufreq.c:428: .target = s3c_cpufreq_target,
intel_pstate.c:2528: .target = intel_cpufreq_target,
cppc_cpufreq.c:401: .target = cppc_cpufreq_set_target,
cpufreq-nforce2.c:371: .target = nforce2_target,
sh-cpufreq.c:163: .target = sh_cpufreq_target,
pcc-cpufreq.c:573: .target = pcc_cpufreq_target,
Similarly to the path taken for target_index() calls in the cpufreq core
during a frequency change, all of the drivers above will mark the end of a
frequency change by a call to cpufreq_freq_transition_end().
Therefore, cpufreq_freq_transition_end() can be used as the location for
the arch_set_freq_scale() call to potentially inform the scheduler of the
frequency change.
This change maintains the previous functionality for the drivers that
implement the target_index() callback, while also adding support for the
few drivers that implement the deprecated target() callback.
fast_switch()
=============
This callback *has* to return the frequency that was selected.
setpolicy()
===========
This callback does not have any designated way of informing what was the
end choice. But there are only two drivers using setpolicy(), and none
of them have current FIE support:
drivers/cpufreq/longrun.c:281: .setpolicy = longrun_set_policy,
drivers/cpufreq/intel_pstate.c:2215: .setpolicy = intel_pstate_set_policy,
The intel_pstate is known to use counter-driven frequency invariance.
Conclusion
==========
Given that the significant majority of current FIE enabled drivers use
callbacks that lend themselves to triggering the setting of the FIE scale
factor in a generic way, move the invariance setter calls to cpufreq core.
As a result of setting the frequency scale factor in cpufreq core, after
callbacks that lend themselves to trigger it, remove this functionality
from the driver side.
To be noted that despite marking a successful frequency change, many
cpufreq drivers will consider the new frequency as the requested
frequency, although this is might not be the one granted by the hardware.
Therefore, the call to arch_set_freq_scale() is a "best effort" one, and
it is up to the architecture if the new frequency is used in the new
frequency scale factor setting (determined by the implementation of
arch_set_freq_scale()) or eventually used by the scheduler (determined
by the implementation of arch_scale_freq_capacity()). The architecture
is in a better position to decide if it has better methods to obtain
more accurate information regarding the current frequency and use that
information instead (for example, the use of counters).
Also, the implementation to arch_set_freq_scale() will now have to handle
error conditions (current frequency == 0) in order to prevent the
overhead in cpufreq core when the default arch_set_freq_scale()
implementation is used.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Suggested-by: Valentin Schneider <valentin.schneider@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
"cpufreq_driver" is guaranteed to be valid here, no need to check it
here.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Allow intel_pstate to work in the passive mode with HWP enabled and
make it set the HWP minimum performance limit (HWP floor) to the
P-state value given by the target frequency supplied by the cpufreq
governor, so as to prevent the HWP algorithm and the CPU scheduler
from working against each other, at least when the schedutil governor
is in use, and update the intel_pstate documentation accordingly.
Among other things, this allows utilization clamps to be taken
into account, at least to a certain extent, when intel_pstate is
in use and makes it more likely that sufficient capacity for
deadline tasks will be provided.
After this change, the resulting behavior of an HWP system with
intel_pstate in the passive mode should be close to the behavior
of the analogous non-HWP system with intel_pstate in the passive
mode, except that the HWP algorithm is generally allowed to make the
CPU run at a frequency above the floor P-state set by intel_pstate in
the entire available range of P-states, while without HWP a CPU can
run in a P-state above the requested one if the latter falls into the
range of turbo P-states (referred to as the turbo range) or if the
P-states of all CPUs in one package are coordinated with each other
at the hardware level.
[Note that in principle the HWP floor may not be taken into account
by the processor if it falls into the turbo range, in which case the
processor has a license to choose any P-state, either below or above
the HWP floor, just like a non-HWP processor in the case when the
target P-state falls into the turbo range.]
With this change applied, intel_pstate in the passive mode assumes
complete control over the HWP request MSR and concurrent changes of
that MSR (eg. via the direct MSR access interface) are overridden by
it.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>
Pull ARM cpufreq driver changes for v5.9-rc1 from Viresh Kumar:
"Here are the details:
- Adaptive voltage scaling (AVS) support and minor cleanups for
brcmstb driver (Florian Fainelli and Markus Mayer).
- A new tegra driver and cleanup for the existing one (Sumit Gupta and
Jon Hunter).
- Bandwidth level support for Qcom driver along with OPP changes (Sibi
Sankar).
- Cleanups to sti, cpufreq-dt, ap806, CPPC drivers (Viresh Kumar, Lee
Jones, Ivan Kokshaysky, Sven Auhagen, and Xin Hao).
- Make schedutil default governor for ARM (Valentin Schneider).
- Fix dependency issues for imx (Walter Lozano).
- Cleanup around cached_resolved_idx in cpufreq core (Viresh Kumar)."
* 'cpufreq/arm/linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/vireshk/pm:
cpufreq: make schedutil the default for arm and arm64
cpufreq: cached_resolved_idx can not be negative
cpufreq: Add Tegra194 cpufreq driver
dt-bindings: arm: Add NVIDIA Tegra194 CPU Complex binding
cpufreq: imx: Select NVMEM_IMX_OCOTP
cpufreq: sti-cpufreq: Fix some formatting and misspelling issues
cpufreq: tegra186: Simplify probe return path
cpufreq: CPPC: Reuse caps variable in few routines
cpufreq: ap806: fix cpufreq driver needs ap cpu clk
cpufreq: cppc: Reorder code and remove apply_hisi_workaround variable
cpufreq: dt: fix oops on armada37xx
cpufreq: brcmstb-avs-cpufreq: send S2_ENTER / S2_EXIT commands to AVS
cpufreq: brcmstb-avs-cpufreq: Support polling AVS firmware
cpufreq: brcmstb-avs-cpufreq: more flexible interface for __issue_avs_command()
cpufreq: qcom: Disable fast switch when scaling DDR/L3
cpufreq: qcom: Update the bandwidth levels on frequency change
OPP: Add and export helper to set bandwidth
cpufreq: blacklist SC7180 in cpufreq-dt-platdev
cpufreq: blacklist SDM845 in cpufreq-dt-platdev
It is not possible for cached_resolved_idx to be invalid here as the
cpufreq core always sets index to a positive value.
Change its type to unsigned int and fix qcom usage a bit.
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Also provide missing function parameter description for 'cpu' and 'policy'.
Fixes the following W=1 kernel build warning(s):
drivers/cpufreq/cpufreq.c:60: warning: cannot understand function prototype: 'struct cpufreq_driver *cpufreq_driver; '
drivers/cpufreq/cpufreq.c:90: warning: Function parameter or member 'cpufreq_policy_notifier_list' not described in 'BLOCKING_NOTIFIER_HEAD'
drivers/cpufreq/cpufreq.c:312: warning: Function parameter or member 'val' not described in 'adjust_jiffies'
drivers/cpufreq/cpufreq.c:312: warning: Function parameter or member 'ci' not described in 'adjust_jiffies'
drivers/cpufreq/cpufreq.c:538: warning: Function parameter or member 'policy' not described in 'cpufreq_driver_resolve_freq'
drivers/cpufreq/cpufreq.c:686: warning: Function parameter or member 'file_name' not described in 'show_one'
drivers/cpufreq/cpufreq.c:686: warning: Function parameter or member 'object' not described in 'show_one'
drivers/cpufreq/cpufreq.c:731: warning: Function parameter or member 'file_name' not described in 'store_one'
drivers/cpufreq/cpufreq.c:731: warning: Function parameter or member 'object' not described in 'store_one'
drivers/cpufreq/cpufreq.c:741: warning: Function parameter or member 'policy' not described in 'show_cpuinfo_cur_freq'
drivers/cpufreq/cpufreq.c:741: warning: Function parameter or member 'buf' not described in 'show_cpuinfo_cur_freq'
drivers/cpufreq/cpufreq.c:754: warning: Function parameter or member 'policy' not described in 'show_scaling_governor'
drivers/cpufreq/cpufreq.c:754: warning: Function parameter or member 'buf' not described in 'show_scaling_governor'
drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'policy' not described in 'store_scaling_governor'
drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'buf' not described in 'store_scaling_governor'
drivers/cpufreq/cpufreq.c:770: warning: Function parameter or member 'count' not described in 'store_scaling_governor'
drivers/cpufreq/cpufreq.c:806: warning: Function parameter or member 'policy' not described in 'show_scaling_driver'
drivers/cpufreq/cpufreq.c:806: warning: Function parameter or member 'buf' not described in 'show_scaling_driver'
drivers/cpufreq/cpufreq.c:815: warning: Function parameter or member 'policy' not described in 'show_scaling_available_governors'
drivers/cpufreq/cpufreq.c:815: warning: Function parameter or member 'buf' not described in 'show_scaling_available_governors'
drivers/cpufreq/cpufreq.c:859: warning: Function parameter or member 'policy' not described in 'show_related_cpus'
drivers/cpufreq/cpufreq.c:859: warning: Function parameter or member 'buf' not described in 'show_related_cpus'
drivers/cpufreq/cpufreq.c:867: warning: Function parameter or member 'policy' not described in 'show_affected_cpus'
drivers/cpufreq/cpufreq.c:867: warning: Function parameter or member 'buf' not described in 'show_affected_cpus'
drivers/cpufreq/cpufreq.c:901: warning: Function parameter or member 'policy' not described in 'show_bios_limit'
drivers/cpufreq/cpufreq.c:901: warning: Function parameter or member 'buf' not described in 'show_bios_limit'
drivers/cpufreq/cpufreq.c:1625: warning: Function parameter or member 'dev' not described in 'cpufreq_remove_dev'
drivers/cpufreq/cpufreq.c:1625: warning: Function parameter or member 'sif' not described in 'cpufreq_remove_dev'
drivers/cpufreq/cpufreq.c:2380: warning: Function parameter or member 'cpu' not described in 'cpufreq_get_policy'
drivers/cpufreq/cpufreq.c:2771: warning: Function parameter or member 'driver' not described in 'cpufreq_unregister_driver'
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The default cpufreq governor is chosen with the help of a "choice"
option in the Kconfig which will always end up selecting one of
the governors and so the weakly defined definition of
cpufreq_default_governor() will never get called.
Moreover, this makes us skip the checking of the return value of
that routine as it will always be non NULL.
If the Kconfig option changes in future, then we will start getting
a link error instead (and it won't go unnoticed as in the case of the
weak definition).
Suggested-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Currently, the only way to specify the default CPUfreq governor is
via Kconfig options, which suits users who can build the kernel
themselves perfectly.
However, for those who use a distro-like kernel (such as Android,
with the Generic Kernel Image project), the only way to use a
non-default governor is to boot to userspace, and to then switch
using the sysfs interface. Being able to specify the default governor
on the command line, like is the case for cpuidle, would allow those
users to specify their governor of choice earlier on, and to simplify
the userspace boot procedure slighlty.
To support this use-case, add a kernel command line parameter
allowing the default governor for CPUfreq to be specified, which
takes precedence over the built-in default.
This implementation has one notable limitation: the default governor
must be registered before the driver. This is solved for builtin
governors and drivers using appropriate *_initcall() functions. And
in the modular case, this must be reflected as a constraint on the
module loading order.
Signed-off-by: Quentin Perret <qperret@google.com>
[ Viresh: Converted 'default_governor' to a string and parsing it only
at initcall level, and several updates to
cpufreq_init_policy(). ]
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The locking around governors handling isn't adequate currently.
The list of governors should never be traversed without the locking
in place. Also governor modules must not be removed while the code
in them is still in use.
Reported-by: Quentin Perret <qperret@google.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
[ rjw: Changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
