cpufreq / intel_pstate: Add function to check that all MSRs are valid

Some VMs seem to try to implement some MSRs but not all the registers
the driver needs.  Check to make sure all the MSR that we need are
available. If any of the required MSRs are not available refuse to
load.

References: https://bugzilla.redhat.com/show_bug.cgi?id=922923
Reported-by: Josh Stone <jistone@redhat.com>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq / intel_pstate: Fix calculation of current frequency

Use the correct pstate value to calculate the effective frequency.

References: https://bugzilla.redhat.com/show_bug.cgi?id=923942
Reported-by: Satish Balay <balay@fastmail.fm>
Signed-off-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
intel-pstate: Use #defines instead of hard-coded values.

They are defined in coreboot (MSR_PLATFORM) and the other
one is already defined in msr-index.h.

Let's use those.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: stats: do cpufreq_cpu_put() corresponding to cpufreq_cpu_get()

In cpufreq_stats_free_sysfs() we aren't balancing calls to
cpufreq_cpu_get() with cpufreq_cpu_put(). This will never let us have
ref count to policy->kobj as zero.

We will get a hang if somehow cpufreq_driver_unregister() is called.
And that can happen when we compile our driver as module and
insmod/rmmod it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Amit Kucheria <amit.kucheria@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: acpi-cpufreq: Don't set policy->related_cpus from .init()

With the addition of following patch:

fcf8058 cpufreq: Simplify cpufreq_add_dev()

cpufreq driver's .init() routine must initialize policy->cpus with
mask of all possible CPUs (Online + Offline) that share the clock.
Then the core would copy this mask onto policy->related_cpus and will
reset policy->cpus to carry only online cpus.

acpi-cpufreq driver wasn't updated with this assumption and so
sometimes when we try to hot[un]plug CPUs at run time, sysfs
directories get corrupted.

This patch fixes acpi-cpufreq driver against this corruption.

Reported-and-tested-by: Maciej Rutecki <maciej.rutecki@gmail.com>
Tested-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Merge branch 'pm-fixes-next' into fixes-next

* pm-fixes-next:
  cpufreq: acpi-cpufreq: Don't set policy->related_cpus from .init()
  cpufreq: stats: do cpufreq_cpu_put() corresponding to cpufreq_cpu_get()
  intel-pstate: Use #defines instead of hard-coded values.
  cpufreq / intel_pstate: Fix calculation of current frequency
  cpufreq / intel_pstate: Add function to check that all MSRs are valid
Merge branch 'acpi-fixes-next' into fixes-next

* acpi-fixes-next:
  ACPI/APEI: fix error status check condition for CPER
  acpi: fix suspend and resume on Sony Vaio VGN-FW21M
Merge branch 'fixes-next' into linux-next

* fixes-next:
  cpufreq: acpi-cpufreq: Don't set policy->related_cpus from .init()
  cpufreq: stats: do cpufreq_cpu_put() corresponding to cpufreq_cpu_get()
  intel-pstate: Use #defines instead of hard-coded values.
  cpufreq / intel_pstate: Fix calculation of current frequency
  cpufreq / intel_pstate: Add function to check that all MSRs are valid
  ACPI/APEI: fix error status check condition for CPER
  acpi: fix suspend and resume on Sony Vaio VGN-FW21M
cpufreq: Convert the cpufreq_driver_lock to a rwlock

This eliminates the contention I am seeing in __cpufreq_cpu_get.
It also nicely stages the lock to be replaced by the rcu.

Signed-off-by: Nathan Zimmer <nzimmer@sgi.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Add per policy governor-init/exit infrastructure

Currently, there can't be multiple instances of single governor_type. If we have
a multi-package system, where we have multiple instances of struct policy (per
package), we can't have multiple instances of same governor. i.e. We can't have
multiple instances of ondemand governor for multiple packages.

Governors directory in sysfs is created at /sys/devices/system/cpu/cpufreq/
governor-name/. Which again reflects that there can be only one instance of a
governor_type in the system.

This is a bottleneck for multicluster system, where we want different packages
to use same governor type, but with different tunables.

This patch is inclined towards providing this infrastructure. Because we are
required to allocate governor's resources dynamically now, we must do it at
policy creation and end. And so got CPUFREQ_GOV_POLICY_INIT/EXIT.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: governor: Implement per policy instances of governors

Currently, there can't be multiple instances of single governor_type. If we have
a multi-package system, where we have multiple instances of struct policy (per
package), we can't have multiple instances of same governor. i.e. We can't have
multiple instances of ondemand governor for multiple packages.

Governors directory in sysfs is created at /sys/devices/system/cpu/cpufreq/
governor-name/. Which again reflects that there can be only one instance of a
governor_type in the system.

This is a bottleneck for multicluster system, where we want different packages
to use same governor type, but with different tunables.

This patch uses the infrastructure provided by earlier patch and implements
init/exit routines for ondemand and conservative governors.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: Get rid of "struct global_attr"

We don't need to keep two structures for file attributes, global_attr and
freq_attr. Lets use freq_attr only for cpufreq core and drivers.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: governor: Set MIN_LATENCY_MULTIPLIER to 20

Currently MIN_LATENCY_MULTIPLIER is set defined as 100 and so on a system with
transition latency of 1 ms, the minimum sampling time comes to be around 100 ms.
That is quite big if you want to get better performance for your system.

Redefine MIN_LATENCY_MULTIPLIER to 20 so that we can support 20ms sampling rate
for such platforms.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: ondemand: Don't update sample_type if we don't evaluate load again

Because we have per cpu timer now, we check if we need to evaluate load again or
not (In case it is recently evaluated). Here the 2nd cpu which got timer
interrupt updates core_dbs_info->sample_type irrespective of load evaluation is
required or not. Which is wrong as the first cpu is dependent on this variable
set to an older value.

Moreover it would be best in this case to schedule 2nd cpu's timer to
sampling_rate instead of freq_lo or hi as that must be managed by the other cpu.
In case the other cpu idles in between then also we wouldn't loose much power.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: governors: Avoid unnecessary per cpu timer interrupts

Following patch has introduced per cpu timers or works for ondemand and
conservative governors.

	commit 2abfa876f1117b0ab45f191fb1f82c41b1cbc8fe
	Author: Rickard Andersson <rickard.andersson@stericsson.com>
	Date:   Thu Dec 27 14:55:38 2012 +0000

	    cpufreq: handle SW coordinated CPUs

This causes additional unnecessary interrupts on all cpus when the load is
recently evaluated by any other cpu. i.e. When load is recently evaluated by cpu
x, we don't really need any other cpu to evaluate this load again for the next
sampling_rate time.

Some sort of code is present to avoid that but we are still getting timer
interrupts for all cpus. A good way of avoiding this would be to modify delays
for all cpus (policy->cpus) whenever any cpu has evaluated load.

This patch does this change and some related code cleanup.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: conservative: Break out earlier on the lowest frequency

If we're on the lowest frequency, no need to calculate new freq.
Break out even earlier in this case.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: conservative: Fix relation when decreasing frequency

The relation should be CPUFREQ_RELATION_L to find optimal frequency
when decreasing.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: governors: Calculate iowait time only when necessary

Currently we always calculate the CPU iowait time and add it to idle time.
If we are in ondemand and we use io_is_busy, we re-calculate iowait time
and we subtract it from idle time.

With this patch iowait time is calculated only when necessary avoiding
the double call to get_cpu_iowait_time_us. We use a parameter in
function get_cpu_idle_time to distinguish when the iowait time will be
added to idle time or not, without the need of keeping the prev_io_wait.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.,org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: conservative: Fix sampling_down_factor functionality

sampling_down_factor tunable is unused since commit
8e677ce83bf41ba9c74e5b6d9ee60b07d4e5ed93 (4 years ago).

This patch restores the original functionality and documents the
tunable.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
cpufreq: conservative: Fix the logic in frequency decrease checking

When we evaluate the CPU load for frequency decrease we have to compare
the load against down_threshold. There is no need to subtract 10 points
from down_threshold.

Instead, we have to use the default down_threshold or user's selection
unmodified.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>