Commit Graph

102 Commits

Author SHA1 Message Date
Shaokun Zhang 5de1262500 cpufreq: stats: Clean up local variable in cpufreq_stats_create_table()
Local variable 'count' will be initialized and 'ret' is also not
required, so remove the redundant initialization and get rid of
'ret'.

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>
2021-06-07 13:47:57 +02:00
Viresh Kumar 7854c7520b cpufreq: stats: Use local_clock() instead of jiffies
local_clock() has better precision and accuracy as compared to jiffies,
lets use it for time management in cpufreq stats.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-12-11 19:53:58 +01:00
Viresh Kumar b7af6080a3 cpufreq: stats: Fix string format specifier mismatch
Fix following warning:

drivers/cpufreq/cpufreq_stats.c:63:10: warning: %d in format string (no.
1) requires 'int' but the argument type is 'unsigned int'

Fixes: 40c3bd4cfa ("cpufreq: stats: Defer stats update to cpufreq_stats_record_transition()")
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-12 12:32:10 +02:00
Rafael J. Wysocki efad4240da cpufreq: stats: Add memory barrier to store_reset()
There is nothing to prevent the CPU or the compiler from reordering
the writes to stats->reset_time and stats->reset_pending in
store_reset(), in which case the readers of stats->reset_time may see
a stale value.  Moreover, on 32-bit arches the write to reset_time
cannot be completed in one go, so the readers of it may see a
partially updated value in that case.

To prevent that from happening, add a write memory barrier between
the writes to stats->reset_time and stats->reset_pending in
store_reset() and corresponding read memory barrier in the
readers of stats->reset_time.

Fixes: 40c3bd4cfa ("cpufreq: stats: Defer stats update to cpufreq_stats_record_transition()")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2020-10-07 17:13:15 +02:00
Viresh Kumar 96f60cddf7 cpufreq: stats: Enable stats for fast-switch as well
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>
2020-10-05 15:13:43 +02:00
Viresh Kumar 4958b46efb cpufreq: stats: Mark few conditionals with unlikely()
Since this will be part of the scheduler's hotpath in some cases, use
unlikely() for few of the obvious conditionals.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-05 15:13:43 +02:00
Viresh Kumar 381abb942a cpufreq: stats: Remove locking
The locking isn't required anymore as stats can get updated only from
one place at a time. Remove it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-05 15:13:43 +02:00
Viresh Kumar 40c3bd4cfa cpufreq: stats: Defer stats update to cpufreq_stats_record_transition()
In order to prepare for lock-less stats update, add support to defer any
updates to it until cpufreq_stats_record_transition() is called.

The stats were updated from two places earlier:

- show_time_in_state(): This can be easily deferred, all we need is to
  calculate the delta duration again in this routine to show the current
  state's time-in-state.

- store_reset(): This is a bit tricky as we need to clear the stats
  here and avoid races with simultaneous call to
  cpufreq_stats_record_transition().

Fix that by deferring the reset of the stats (within the code) to the
next call to cpufreq_stats_record_transition(), but since we need to
keep showing the right stats until that time, we capture the reset
time and account for the time since last time reset was called until
the time cpufreq_stats_record_transition() update the stats.

User space will continue seeing the stats correctly, everything will
be 0 after the stats are reset, apart from the time-in-state of the
current state, until the time a frequency switch happens.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Minor changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-10-05 15:13:42 +02:00
Takashi Iwai 3c0897c180 cpufreq: Use scnprintf() for avoiding potential buffer overflow
Since snprintf() returns the would-be-output size instead of the
actual output size, the succeeding calls may go beyond the given
buffer limit.  Fix it by replacing with scnprintf().

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2020-03-14 12:07:38 +01:00
Thomas Gleixner d2912cb15b 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 <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-06-19 17:09:55 +02:00
Kyle Lin fcccc5c838 cpufreq: stats: Use lock by stat to replace global spin lock
Stats is updated by each policy, using the lock by stat can
reduce the contention.

Signed-off-by: Kyle Lin <linkyle0915@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-04-09 11:31:48 +02:00
Viresh Kumar 9795607dc4 cpufreq: stats: Fix concurrency issues while resetting stats
It is possible for cpufreq_stats_clear_table() and
cpufreq_stats_record_transition() to get called concurrently and they
will try to update same variables simultaneously and may lead to
corruption of data.

Prevent that with the help of existing spinlock.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-01 11:52:11 +01:00
Viresh Kumar 10b818211d cpufreq: stats: Declare freq-attr right after their callbacks
Freq attribute for "trans_table" is defined right after its callback
(without any blank line between them), but the others are defined
separately later on. Keep this consistent and define all attributes
right after their callbacks.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-01 11:52:11 +01:00
Viresh Kumar d476ec4f7f cpufreq: stats: Change return type of cpufreq_stats_update() as void
It always returns 0 and none of its callers check its return value. Make
it return void.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2018-01-05 13:22:46 +01:00
Gautham R. Shenoy f7bc9b209e cpufreq: stats: Handle the case when trans_table goes beyond PAGE_SIZE
On platforms with large number of Pstates, the transition table, which
is a NxN matrix, can overflow beyond the PAGE_SIZE boundary.

This can be seen on POWER9 which has 100+ Pstates.

As a result, each time the trans_table is read for any of the CPUs, we
will get the following error.

---------------------------------------------------
fill_read_buffer: show+0x0/0xa0 returned bad count
---------------------------------------------------

This patch ensures that in case of an overflow, we print a warning
once in the dmesg and return FILE TOO LARGE error for this and all
subsequent accesses of trans_table.

Signed-off-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-11-08 23:41:25 +01:00
Linus Torvalds 4d25ec1966 Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux
Pull thermal management updates from Zhang Rui:

 - Improve thermal cpu_cooling interaction with cpufreq core.

   The cpu_cooling driver is designed to use CPU frequency scaling to
   avoid high thermal states for a platform. But it wasn't glued really
   well with cpufreq core.

   For example clipped-cpus is copied from the policy structure and its
   much better to use the policy->cpus (or related_cpus) fields directly
   as they may have got updated. Not that things were broken before this
   series, but they can be optimized a bit more.

   This series tries to improve interactions between cpufreq core and
   cpu_cooling driver and does some fixes/cleanups to the cpu_cooling
   driver. (Viresh Kumar)

 - A couple of fixes and cleanups in thermal core and imx, hisilicon,
   bcm_2835, int340x thermal drivers. (Arvind Yadav, Dan Carpenter,
   Sumeet Pawnikar, Srinivas Pandruvada, Willy WOLFF)

* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (24 commits)
  thermal: bcm2835: fix an error code in probe()
  thermal: hisilicon: Handle return value of clk_prepare_enable
  thermal: imx: Handle return value of clk_prepare_enable
  thermal: int340x: check for sensor when PTYP is missing
  Thermal/int340x: Fix few typos and kernel-doc style
  thermal: fix source code documentation for parameters
  thermal: cpu_cooling: Replace kmalloc with kmalloc_array
  thermal: cpu_cooling: Rearrange struct cpufreq_cooling_device
  thermal: cpu_cooling: 'freq' can't be zero in cpufreq_state2power()
  thermal: cpu_cooling: don't store cpu_dev in cpufreq_cdev
  thermal: cpu_cooling: get_level() can't fail
  thermal: cpu_cooling: create structure for idle time stats
  thermal: cpu_cooling: merge frequency and power tables
  thermal: cpu_cooling: get rid of 'allowed_cpus'
  thermal: cpu_cooling: OPPs are registered for all CPUs
  thermal: cpu_cooling: store cpufreq policy
  cpufreq: create cpufreq_table_count_valid_entries()
  thermal: cpu_cooling: use cpufreq_policy to register cooling device
  thermal: cpu_cooling: get rid of a variable in cpufreq_set_cur_state()
  thermal: cpu_cooling: remove cpufreq_cooling_get_level()
  ...
2017-07-14 13:12:32 -07:00
Arvind Yadav 402202e8de cpufreq: cpufreq_stats: constify attribute_group structures
attribute_groups are not supposed to change at runtime. All functions
working with attribute_groups provided by <linux/sysfs.h> work with const
attribute_group. So mark the non-const structs as const.

File size before:
   text	   data	    bss	    dec	    hex	filename
   1655	    256	      4	   1915	    77b	drivers/cpufreq/cpufreq_stats.o

File size After adding 'const':
   text	   data	    bss	    dec	    hex	filename
   1695	    192	      4	   1891	    763	drivers/cpufreq/cpufreq_stats.o

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-04 22:03:13 +02:00
Viresh Kumar 55d8529313 cpufreq: create cpufreq_table_count_valid_entries()
We need such a routine at two places already, lets create one.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Lukasz Luba <lukasz.luba@arm.com>
Tested-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2017-05-27 17:32:28 -07:00
Linus Torvalds 02c3de1105 Power management updates for v4.11-rc1
- Operating Performance Points (OPP) framework fixes, cleanups and
    switch over from RCU-based synchronization to reference counting
    using krefs (Viresh Kumar, Wei Yongjun, Dave Gerlach).
 
  - cpufreq core cleanups and documentation updates (Viresh Kumar,
    Rafael Wysocki).
 
  - New cpufreq driver for Broadcom BMIPS SoCs (Markus Mayer).
 
  - New cpufreq-dt sub-driver for TI SoCs requiring special handling,
    like in the AM335x, AM437x, DRA7x, and AM57x families, along with
    new DT bindings for it (Dave Gerlach, Paul Gortmaker).
 
  - ARM64 SoCs support for the qoriq cpufreq driver (Tang Yuantian).
 
  - intel_pstate driver updates including a new sysfs knob to control
    the driver's operation mode and fixes related to the no_turbo
    sysfs knob and the hardware-managed P-states feature support
    (Rafael Wysocki, Srinivas Pandruvada).
 
  - New interface to export ultra-turbo frequencies for the powernv
    cpufreq driver (Shilpasri Bhat).
 
  - Assorted fixes for cpufreq drivers (Arnd Bergmann, Dan Carpenter,
    Wei Yongjun).
 
  - devfreq core fixes, mostly related to the sysfs interface exported
    by it (Chanwoo Choi, Chris Diamand).
 
  - Updates of the exynos-bus and exynos-ppmu devfreq drivers (Chanwoo
    Choi).
 
  - Device PM QoS extension to support CPUs and support for per-CPU
    wakeup (device resume) latency constraints in the cpuidle menu
    governor (Alex Shi).
 
  - Wakeup IRQs framework fixes (Grygorii Strashko).
 
  - Generic power domains framework update including a fix to make
    it handle asynchronous invocations of *noirq suspend/resume
    callbacks correctly (Ulf Hansson, Geert Uytterhoeven).
 
  - Assorted fixes and cleanups in the core suspend/hibernate code,
    PM QoS framework and x86 ACPI idle support code (Corentin Labbe,
    Geert Uytterhoeven, Geliang Tang, John Keeping, Nick Desaulniers).
 
  - Update of the analyze_suspend.py script is updated to version 4.5
    offering multiple improvements (Todd Brandt).
 
  - New tool for intel_pstate diagnostics using the pstate_sample
    tracepoint (Doug Smythies).
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Merge tag 'pm-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "The majority of changes go into the Operating Performance Points (OPP)
  framework and cpufreq this time, followed by devfreq and some
  scattered updates all over.

  The OPP changes are mostly related to switching over from RCU-based
  synchronization, that turned out to be overly complicated and
  problematic, to reference counting using krefs.

  In the cpufreq land there are core cleanups, documentation updates, a
  new driver for Broadcom BMIPS SoCs, a new cpufreq-dt sub-driver for TI
  SoCs that require special handling, ARM64 SoCs support for the qoriq
  driver, intel_pstate updates, powernv driver update and assorted
  fixes.

  The devfreq changes are mostly fixes related to the sysfs interface
  and some Exynos drivers updates.

  Apart from that, the cpuidle menu governor will support per-CPU PM QoS
  constraints for the wakeup latency now, some bugs in the wakeup IRQs
  framework are fixed, the generic power domains framework should handle
  asynchronous invocations of *noirq suspend/resume callbacks from now
  on, the analyze_suspend.py script is updated and there is a new tool
  for intel_pstate diagnostics.

  Specifics:

   - Operating Performance Points (OPP) framework fixes, cleanups and
     switch over from RCU-based synchronization to reference counting
     using krefs (Viresh Kumar, Wei Yongjun, Dave Gerlach)

   - cpufreq core cleanups and documentation updates (Viresh Kumar,
     Rafael Wysocki)

   - New cpufreq driver for Broadcom BMIPS SoCs (Markus Mayer)

   - New cpufreq-dt sub-driver for TI SoCs requiring special handling,
     like in the AM335x, AM437x, DRA7x, and AM57x families, along with
     new DT bindings for it (Dave Gerlach, Paul Gortmaker)

   - ARM64 SoCs support for the qoriq cpufreq driver (Tang Yuantian)

   - intel_pstate driver updates including a new sysfs knob to control
     the driver's operation mode and fixes related to the no_turbo sysfs
     knob and the hardware-managed P-states feature support (Rafael
     Wysocki, Srinivas Pandruvada)

   - New interface to export ultra-turbo frequencies for the powernv
     cpufreq driver (Shilpasri Bhat)

   - Assorted fixes for cpufreq drivers (Arnd Bergmann, Dan Carpenter,
     Wei Yongjun)

   - devfreq core fixes, mostly related to the sysfs interface exported
     by it (Chanwoo Choi, Chris Diamand)

   - Updates of the exynos-bus and exynos-ppmu devfreq drivers (Chanwoo
     Choi)

   - Device PM QoS extension to support CPUs and support for per-CPU
     wakeup (device resume) latency constraints in the cpuidle menu
     governor (Alex Shi)

   - Wakeup IRQs framework fixes (Grygorii Strashko)

   - Generic power domains framework update including a fix to make it
     handle asynchronous invocations of *noirq suspend/resume callbacks
     correctly (Ulf Hansson, Geert Uytterhoeven)

   - Assorted fixes and cleanups in the core suspend/hibernate code, PM
     QoS framework and x86 ACPI idle support code (Corentin Labbe, Geert
     Uytterhoeven, Geliang Tang, John Keeping, Nick Desaulniers)

   - Update of the analyze_suspend.py script is updated to version 4.5
     offering multiple improvements (Todd Brandt)

   - New tool for intel_pstate diagnostics using the pstate_sample
     tracepoint (Doug Smythies)"

* tag 'pm-4.11-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (85 commits)
  MAINTAINERS: cpufreq: add bmips-cpufreq.c
  PM / QoS: Fix memory leak on resume_latency.notifiers
  PM / Documentation: Spelling s/wrtie/write/
  PM / sleep: Fix test_suspend after sleep state rework
  cpufreq: CPPC: add ACPI_PROCESSOR dependency
  cpufreq: make ti-cpufreq explicitly non-modular
  cpufreq: Do not clear real_cpus mask on policy init
  tools/power/x86: Debug utility for intel_pstate driver
  AnalyzeSuspend: fix drag and zoom bug in javascript
  PM / wakeirq: report a wakeup_event on dedicated wekup irq
  PM / wakeirq: Fix spurious wake-up events for dedicated wakeirqs
  PM / wakeirq: Enable dedicated wakeirq for suspend
  cpufreq: dt: Don't use generic platdev driver for ti-cpufreq platforms
  cpufreq: ti: Add cpufreq driver to determine available OPPs at runtime
  Documentation: dt: add bindings for ti-cpufreq
  PM / OPP: Expose _of_get_opp_desc_node as dev_pm_opp API
  cpufreq: qoriq: Don't look at clock implementation details
  cpufreq: qoriq: add ARM64 SoCs support
  PM / Domains: Provide dummy governors if CONFIG_PM_GENERIC_DOMAINS=n
  cpufreq: brcmstb-avs-cpufreq: remove unnecessary platform_set_drvdata()
  ...
2017-02-20 17:41:31 -08:00
Viresh Kumar 801e0f378f cpufreq: Remove CONFIG_CPU_FREQ_STAT_DETAILS config option
This doesn't have any benefit apart from saving a small amount of memory
when it is disabled. The ifdef hackery in the code makes it dirty
unnecessarily.

Clean it up by removing the Kconfig option completely. Few defconfigs
are also updated and CONFIG_CPU_FREQ_STAT_DETAILS is replaced with
CONFIG_CPU_FREQ_STAT now in them, as users wanted stats to be enabled.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-03 23:59:39 +01:00
Frederic Weisbecker 7fb1327ee9 sched/cputime: Convert kcpustat to nsecs
Kernel CPU stats are stored in cputime_t which is an architecture
defined type, and hence a bit opaque and requiring accessors and mutators
for any operation.

Converting them to nsecs simplifies the code and is one step toward
the removal of cputime_t in the core code.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>
Link: http://lkml.kernel.org/r/1485832191-26889-4-git-send-email-fweisbec@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-02-01 09:13:47 +01:00
Markus Mayer ee7930ee27 cpufreq: stats: New sysfs attribute for clearing statistics
Allow CPUfreq statistics to be cleared by writing anything to
/sys/.../cpufreq/stats/reset.

Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-11-11 01:51:11 +01:00
Viresh Kumar f8bfc116ca cpufreq: Remove cpufreq_frequency_get_table()
Most of the callers of cpufreq_frequency_get_table() already have the
pointer to a valid 'policy' structure and they don't really need to go
through the per-cpu variable first and then a check to validate the
frequency, in order to find the freq-table for the policy.

Directly use the policy->freq_table field instead for them.

Only one user of that API is left after above changes, cpu_cooling.c and
it accesses the freq_table in a racy way as the policy can get freed in
between.

Fix it by using cpufreq_cpu_get() properly.

Since there are no more users of cpufreq_frequency_get_table() left, get
rid of it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Javi Merino <javi.merino@arm.com> (cpu_cooling.c)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-06-09 00:58:05 +02:00
Rafael J. Wysocki 1aefc75b24 cpufreq: stats: Make the stats code non-modular
The modularity of cpufreq_stats is quite problematic.

First off, the usage of policy notifiers for the initialization
and cleanup in the cpufreq_stats module is inherently racy with
respect to CPU offline/online and the initialization and cleanup
of the cpufreq driver.

Second, fast frequency switching (used by the schedutil governor)
cannot be enabled if any transition notifiers are registered, so
if the cpufreq_stats module (that registers a transition notifier
for updating transition statistics) is loaded, the schedutil governor
cannot use fast frequency switching.

On the other hand, allowing cpufreq_stats to be built as a module
doesn't really add much value.  Arguably, there's not much reason
for that code to be modular at all.

For the above reasons, make the cpufreq stats code non-modular,
modify the core to invoke functions provided by that code directly
and drop the notifiers from it.

Make the stats sysfs attributes appear empty if fast frequency
switching is enabled as the statistics will not be updated in that
case anyway (and returning -EBUSY from those attributes breaks
powertop).

While at it, clean up Kconfig help for the CPU_FREQ_STAT and
CPU_FREQ_STAT_DETAILS options.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-06-02 23:24:41 +02:00
Viresh Kumar 490285c65e cpufreq: stats: drop unnecessary locking
There is no possibility of any race on updating last_index, trans_table or
total_trans as these are updated only by cpufreq_stat_notifier_trans() which
will be called sequentially.

The only place where locking is still relevant is: cpufreq_stats_update(), which
updates time_in_state and last_time. This can be called by two thread in
parallel, that may result in races.

The two threads being:
- sysfs read of time_in_state
- and frequency transition that calls cpufreq_stat_notifier_trans().

Remove locking from the first case mentioned above.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:45 +01:00
Viresh Kumar e73476949c cpufreq: stats: don't update stats on false notifiers
We need to call cpufreq_stats_update() to update 'time_in_state' for the last
frequency. This is achieved by calling it from cpufreq_stat_notifier_trans(),
which is called after frequency transition.

But if we detect that the cpu's frequency haven't really changed and its a false
POSTCHANGE notification, we don't really need to update time_in_state.

It wouldn't cause any harm in calling cpufreq_stats_update() but we can avoid
calling it here and call it when the frequency really changes. The result will
be the same but more efficient.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:45 +01:00
Viresh Kumar 9225913d38 cpufreq: stats: don't update stats from show_trans_table()
cpufreq_stats_update() updates time_in_state and nothing else. It should ideally
be updated only in two cases:
- User requested for the current value of time_in_state.
- We have switched states and so need to update time for the last state.

Currently, we are also doing this while user asks for the transition table of
frequencies. It wouldn't do any harm, but no good as well. Its useless here.

Remove it.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:45 +01:00
Viresh Kumar c960f9b22d cpufreq: stats: time_in_state can't be NULL in cpufreq_stats_update()
'time_in_state' can't be NULL if 'stats' is valid. These are allocated together
and only if time_in_state is allocated successfully, we update policy->stats.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:44 +01:00
Viresh Kumar a685c6d023 cpufreq: stats: create sysfs group once we are ready
Userspace is free to read value of any file from cpufreq/stats directory once
they are created. __cpufreq_stats_create_table() is creating the sysfs files
first and then allocating resources for them. Though it would be quite difficult
to trigger the racy situation here, but for the sake of keeping sensible code
lets create sysfs entries only after we are ready to go.

This also does some makeup to the routine to make it look better.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:44 +01:00
Viresh Kumar c92f2125ac cpufreq: stats: drop 'cpu' field of struct cpufreq_stats
'cpu' field of struct cpufreq_stats isn't used anymore and so can be dropped.
This change makes cpufreq_stats_update_policy_cpu() empty and so that is removed
as well.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:44 +01:00
Viresh Kumar 5094160786 cpufreq: stats: rename 'struct cpufreq_stats' objects as 'stats'
Currently we name objects of 'struct cpufreq_stats' as 'stat' and 'stats'.
Use 'stats' to make it consistent.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:44 +01:00
Viresh Kumar a9aaf2915e cpufreq: stats: get rid of per-cpu cpufreq_stats_table
All CPUs sharing a cpufreq policy share stats too. For this reason,
add a stats pointer to struct cpufreq_policy and drop per-CPU variable
cpufreq_stats_table used for accessing cpufreq stats so as to reduce
code complexity.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:44 +01:00
Viresh Kumar 2aba0c1bae cpufreq: stats: pass 'stat' to cpufreq_stats_update()
It is better to pass a struct cpufreq_stats pointer to cpufreq_stats_update()
instead of a CPU number, because that's all it needs.

Even if we pass a cpu number to cpufreq_stats_update(), it reads the per-cpu
variable to get 'stats' out of it. So we are doing these operations
unnecessarily:
- First getting the cpu number to pass to cpufreq_stats_update(), stat->cpu.
- And then getting stats from the cpu, per_cpu(cpufreq_stats_table, cpu).

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:44 +01:00
Viresh Kumar f93dbbbd10 cpufreq: stats: don't check for freq table while freeing stats
While we allocate stats, we do need to check if freq-table is present
or not as we need to use it then. But while freeing stats, all we need
to know is if stats holds a valid pointer value. There is no use of
testing if cpufreq table is present or not.

Don't check it.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:43 +01:00
Viresh Kumar 9531347c61 cpufreq: stats: initialize 'cur_time' on its definition
'cur_time' is defined in the first line and is then assigned a value
in the next line. Initialize it while defining it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:43 +01:00
Viresh Kumar 43b9cdaf5c cpufreq: stats: remove unused cpufreq_stats_attribute
It was never used, but is there since the first commit. Remove it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:43 +01:00
Viresh Kumar b8c674482f cpufreq: stats: return -EEXIST when stats are already allocated
__cpufreq_stats_create_table() is called from:

- cpufreq notifier on creation of a new policy. Stats will always be
  NULL here.
- cpufreq_stats_init() for all CPUs as cpufreq-stats might have been
  initialized after cpufreq driver. For any policy, 'stats' will be
  NULL for the first CPU only and will be valid for all other CPUs
  managed by the same policy.

While we return for other CPUs, we don't return the right error value.
It's not that we would fail with -EBUSY. But generally, this is what
these return values mean:
- EBUSY: we are busy right now, try again. And the retry attempt might
  be immediate.
- EEXIST: We already have what you are trying to create and there is no
  need to create it again, and so no more tries are required.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:43 +01:00
Viresh Kumar 00d0b29472 cpufreq: stats: Improve module description string
The MODULE_DESCRIPTION() string is just too long and then is broken into
multiple lines just to make checkpatch happy.

Rewrite it to make it more precise.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-01-23 23:06:43 +01:00
Stratos Karafotis 041526f915 cpufreq: Use cpufreq_for_each_* macros for frequency table iteration
The cpufreq core now supports the cpufreq_for_each_entry and
cpufreq_for_each_valid_entry macros helpers for iteration over the
cpufreq_frequency_table, so use them.

It should have no functional changes.

Signed-off-by: Stratos Karafotis <stratosk@semaphore.gr>
Acked-by: Lad, Prabhakar <prabhakar.csengg@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-04-30 00:06:21 +02:00
Linus Torvalds 4dedde7c7a ACPI and power management updates for 3.15-rc1
- Device PM QoS support for latency tolerance constraints on systems with
    hardware interfaces allowing such constraints to be specified.  That is
    necessary to prevent hardware-driven power management from becoming
    overly aggressive on some systems and to prevent power management
    features leading to excessive latencies from being used in some cases.
 
  - Consolidation of the handling of ACPI hotplug notifications for device
    objects.  This causes all device hotplug notifications to go through
    the root notify handler (that was executed for all of them anyway
    before) that propagates them to individual subsystems, if necessary,
    by executing callbacks provided by those subsystems (those callbacks
    are associated with struct acpi_device objects during device
    enumeration).  As a result, the code in question becomes both smaller
    in size and more straightforward and all of those changes should not
    affect users.
 
  - ACPICA update, including fixes related to the handling of _PRT in cases
    when it is broken and the addition of "Windows 2013" to the list of
    supported "features" for _OSI (which is necessary to support systems
    that work incorrectly or don't even boot without it).  Changes from
    Bob Moore and Lv Zheng.
 
  - Consolidation of ACPI _OST handling from Jiang Liu.
 
  - ACPI battery and AC fixes allowing unusual system configurations to
    be handled by that code from Alexander Mezin.
 
  - New device IDs for the ACPI LPSS driver from Chiau Ee Chew.
 
  - ACPI fan and thermal optimizations related to system suspend and resume
    from Aaron Lu.
 
  - Cleanups related to ACPI video from Jean Delvare.
 
  - Assorted ACPI fixes and cleanups from Al Stone, Hanjun Guo, Lan Tianyu,
    Paul Bolle, Tomasz Nowicki.
 
  - Intel RAPL (Running Average Power Limits) driver cleanups from Jacob Pan.
 
  - intel_pstate fixes and cleanups from Dirk Brandewie.
 
  - cpufreq fixes related to system suspend/resume handling from Viresh Kumar.
 
  - cpufreq core fixes and cleanups from Viresh Kumar, Stratos Karafotis,
    Saravana Kannan, Rashika Kheria, Joe Perches.
 
  - cpufreq drivers updates from Viresh Kumar, Zhuoyu Zhang, Rob Herring.
 
  - cpuidle fixes related to the menu governor from Tuukka Tikkanen.
 
  - cpuidle fix related to coupled CPUs handling from Paul Burton.
 
  - Asynchronous execution of all device suspend and resume callbacks,
    except for ->prepare and ->complete, during system suspend and resume
    from Chuansheng Liu.
 
  - Delayed resuming of runtime-suspended devices during system suspend for
    the PCI bus type and ACPI PM domain.
 
  - New set of PM helper routines to allow device runtime PM callbacks to
    be used during system suspend and resume more easily from Ulf Hansson.
 
  - Assorted fixes and cleanups in the PM core from Geert Uytterhoeven,
    Prabhakar Lad, Philipp Zabel, Rashika Kheria, Sebastian Capella.
 
  - devfreq fix from Saravana Kannan.
 
 /
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Merge tag 'pm+acpi-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI and power management updates from Rafael Wysocki:
 "The majority of this material spent some time in linux-next, some of
  it even several weeks.  There are a few relatively fresh commits in
  it, but they are mostly fixes and simple cleanups.

  ACPI took the lead this time, both in terms of the number of commits
  and the number of modified lines of code, cpufreq follows and there
  are a few changes in the PM core and in cpuidle too.

  A new feature that already got some LWN.net's attention is the device
  PM QoS extension allowing latency tolerance requirements to be
  propagated from leaf devices to their ancestors with hardware
  interfaces for specifying latency tolerance.  That should help systems
  with hardware-driven power management to avoid going too far with it
  in cases when there are latency tolerance constraints.

  There also are some significant changes in the ACPI core related to
  the way in which hotplug notifications are handled.  They affect PCI
  hotplug (ACPIPHP) and the ACPI dock station code too.  The bottom line
  is that all those notification now go through the root notify handler
  and are propagated to the interested subsystems by means of callbacks
  instead of having to install a notify handler for each device object
  that we can potentially get hotplug notifications for.

  In addition to that ACPICA will now advertise "Windows 2013"
  compatibility for _OSI, because some systems out there don't work
  correctly if that is not done (some of them don't even boot).

  On the system suspend side of things, all of the device suspend and
  resume callbacks, except for ->prepare() and ->complete(), are now
  going to be executed asynchronously as that turns out to speed up
  system suspend and resume on some platforms quite significantly and we
  have a few more optimizations in that area.

  Apart from that, there are some new device IDs and fixes and cleanups
  all over.  In particular, the system suspend and resume handling by
  cpufreq should be improved and the cpuidle menu governor should be a
  bit more robust now.

  Specifics:

   - Device PM QoS support for latency tolerance constraints on systems
     with hardware interfaces allowing such constraints to be specified.
     That is necessary to prevent hardware-driven power management from
     becoming overly aggressive on some systems and to prevent power
     management features leading to excessive latencies from being used
     in some cases.

   - Consolidation of the handling of ACPI hotplug notifications for
     device objects.  This causes all device hotplug notifications to go
     through the root notify handler (that was executed for all of them
     anyway before) that propagates them to individual subsystems, if
     necessary, by executing callbacks provided by those subsystems
     (those callbacks are associated with struct acpi_device objects
     during device enumeration).  As a result, the code in question
     becomes both smaller in size and more straightforward and all of
     those changes should not affect users.

   - ACPICA update, including fixes related to the handling of _PRT in
     cases when it is broken and the addition of "Windows 2013" to the
     list of supported "features" for _OSI (which is necessary to
     support systems that work incorrectly or don't even boot without
     it).  Changes from Bob Moore and Lv Zheng.

   - Consolidation of ACPI _OST handling from Jiang Liu.

   - ACPI battery and AC fixes allowing unusual system configurations to
     be handled by that code from Alexander Mezin.

   - New device IDs for the ACPI LPSS driver from Chiau Ee Chew.

   - ACPI fan and thermal optimizations related to system suspend and
     resume from Aaron Lu.

   - Cleanups related to ACPI video from Jean Delvare.

   - Assorted ACPI fixes and cleanups from Al Stone, Hanjun Guo, Lan
     Tianyu, Paul Bolle, Tomasz Nowicki.

   - Intel RAPL (Running Average Power Limits) driver cleanups from
     Jacob Pan.

   - intel_pstate fixes and cleanups from Dirk Brandewie.

   - cpufreq fixes related to system suspend/resume handling from Viresh
     Kumar.

   - cpufreq core fixes and cleanups from Viresh Kumar, Stratos
     Karafotis, Saravana Kannan, Rashika Kheria, Joe Perches.

   - cpufreq drivers updates from Viresh Kumar, Zhuoyu Zhang, Rob
     Herring.

   - cpuidle fixes related to the menu governor from Tuukka Tikkanen.

   - cpuidle fix related to coupled CPUs handling from Paul Burton.

   - Asynchronous execution of all device suspend and resume callbacks,
     except for ->prepare and ->complete, during system suspend and
     resume from Chuansheng Liu.

   - Delayed resuming of runtime-suspended devices during system suspend
     for the PCI bus type and ACPI PM domain.

   - New set of PM helper routines to allow device runtime PM callbacks
     to be used during system suspend and resume more easily from Ulf
     Hansson.

   - Assorted fixes and cleanups in the PM core from Geert Uytterhoeven,
     Prabhakar Lad, Philipp Zabel, Rashika Kheria, Sebastian Capella.

   - devfreq fix from Saravana Kannan"

* tag 'pm+acpi-3.15-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (162 commits)
  PM / devfreq: Rewrite devfreq_update_status() to fix multiple bugs
  PM / sleep: Correct whitespace errors in <linux/pm.h>
  intel_pstate: Set core to min P state during core offline
  cpufreq: Add stop CPU callback to cpufreq_driver interface
  cpufreq: Remove unnecessary braces
  cpufreq: Fix checkpatch errors and warnings
  cpufreq: powerpc: add cpufreq transition latency for FSL e500mc SoCs
  MAINTAINERS: Reorder maintainer addresses for PM and ACPI
  PM / Runtime: Update runtime_idle() documentation for return value meaning
  video / output: Drop display output class support
  fujitsu-laptop: Drop unneeded include
  acer-wmi: Stop selecting VIDEO_OUTPUT_CONTROL
  ACPI / gpu / drm: Stop selecting VIDEO_OUTPUT_CONTROL
  ACPI / video: fix ACPI_VIDEO dependencies
  cpufreq: remove unused notifier: CPUFREQ_{SUSPENDCHANGE|RESUMECHANGE}
  cpufreq: Do not allow ->setpolicy drivers to provide ->target
  cpufreq: arm_big_little: set 'physical_cluster' for each CPU
  cpufreq: arm_big_little: make vexpress driver depend on bL core driver
  ACPI / button: Add ACPI Button event via netlink routine
  ACPI: Remove duplicate definitions of PREFIX
  ...
2014-04-01 12:48:54 -07:00
Frederic Weisbecker bfc3f0281e cputime: Default implementation of nsecs -> cputime conversion
The architectures that override cputime_t (s390, ppc) don't provide
any version of nsecs_to_cputime(). Indeed this cputime_t implementation
by backend only happens when CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=y under
which the core code doesn't make any use of nsecs_to_cputime().

At least for now.

We are going to make a broader use of it so lets provide a default
version with a per usecs granularity. It should be good enough for most
usecases.

Cc: Ingo Molnar <mingo@kernel.org>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
2014-03-13 15:56:43 +01:00
Saravana Kannan ad4c2302c2 cpufreq: stats: Refactor common code into __cpufreq_stats_create_table()
cpufreq_frequency_get_table() is called from all callers of
__cpufreq_stats_create_table(). So, move it inside.

Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-02 00:55:50 +01:00
Saravana Kannan 0b7528d963 cpufreq: stats: Fix error handling in __cpufreq_stats_create_table()
Remove sysfs group if __cpufreq_stats_create_table() fails after creating
one.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-02 00:55:50 +01:00
Saravana Kannan b24a5b6512 cpufreq: stats: Remove redundant cpufreq_cpu_get() call
__cpufreq_stats_create_table always gets pass the valid and real policy
struct. So, there's no need to call cpufreq_cpu_get() to get the policy
again.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-03-02 00:55:50 +01:00
Viresh Kumar b3f9ff88db cpufreq: stats: create sysfs entries when cpufreq_stats is a module
When cpufreq_stats is compiled in as a module, cpufreq driver would
have already been registered. And so the CPUFREQ_CREATE_POLICY
notifiers wouldn't be called for it. Hence no sysfs entries for stats. :(

This patch calls cpufreq_stats_create_table() for each online CPU from
cpufreq_stats_init() and so if policy is already created for CPUx then
we will register sysfs stats for it.

When its not compiled as module, we will return early as policy wouldn't
be found for any of the CPUs.

Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-17 02:00:44 +01:00
Viresh Kumar 2d13594dcb cpufreq: stats: free table and remove sysfs entry in a single routine
We don't have code paths now where we need to do these two things
separately, so it is better do them in a single routine. Just as
they are allocated in a single routine.

Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-17 02:00:44 +01:00
Viresh Kumar 027cc2e4a6 cpufreq: stats: remove hotplug notifiers
Either CPUs are hot-unplugged or suspend/resume occurs, cpufreq core
will send notifications to cpufreq-stats and stats structure and sysfs
entries would be correctly handled..

And so we don't actually need hotcpu notifiers in cpufreq-stats anymore.
We were only handling cpu hot-unplug events here and that are already
taken care of by POLICY notifiers.

Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-17 02:00:43 +01:00
Viresh Kumar fcd7af917a cpufreq: stats: handle cpufreq_unregister_driver() and suspend/resume properly
There are several problems with cpufreq stats in the way it handles
cpufreq_unregister_driver() and suspend/resume..

 - We must not lose data collected so far when suspend/resume happens
   and so stats directories must not be removed/allocated during these
   operations, which is done currently.

 - cpufreq_stat has registered notifiers with both cpufreq and hotplug.
   It adds sysfs stats directory with a cpufreq notifier: CPUFREQ_NOTIFY
   and removes this directory with a notifier from hotplug core.

   In case cpufreq_unregister_driver() is called (on rmmod cpufreq driver),
   stats directories per cpu aren't removed as CPUs are still online. The
   only call cpufreq_stats gets is cpufreq_stats_update_policy_cpu() for
   all CPUs except the last of each policy. And pointer to stat information
   is stored in the entry for last CPU in the per-cpu cpufreq_stats_table.
   But policy structure would be freed inside cpufreq core and so that will
   result in memory leak inside cpufreq stats (as we are never freeing
   memory for stats).

   Now if we again insert the module cpufreq_register_driver() will be
   called and we will again allocate stats data and put it on for first
   CPU of every policy.  In case we only have a single CPU per policy, we
   will return with a error from cpufreq_stats_create_table() due to this
   code:

	if (per_cpu(cpufreq_stats_table, cpu))
		return -EBUSY;

   And so probably cpufreq stats directory would not show up anymore (as
   it was added inside last policies->kobj which doesn't exist anymore).
   I haven't tested it, though. Also the values in stats files wouldn't
   be refreshed as we are using the earlier stats structure.

 - CPUFREQ_NOTIFY is called from cpufreq_set_policy() which is called for
   scenarios where we don't really want cpufreq_stat_notifier_policy() to get
   called. For example whenever we are changing anything related to a policy:
   min/max/current freq, etc. cpufreq_set_policy() is called and so cpufreq
   stats is notified. Where we don't do any useful stuff other than simply
   returning with -EBUSY from cpufreq_stats_create_table(). And so this
   isn't the right notifier that cpufreq stats..

 Due to all above reasons this patch does following changes:
 - Add new notifiers CPUFREQ_CREATE_POLICY and CPUFREQ_REMOVE_POLICY,
   which are only called when policy is created/destroyed. They aren't
   called for suspend/resume paths..
 - Use these notifiers in cpufreq_stat_notifier_policy() to create/destory
   stats sysfs entries. And so cpufreq_unregister_driver() or suspend/resume
   shouldn't be a problem for cpufreq_stats.
 - Return early from cpufreq_stat_cpu_callback() for suspend/resume sequence,
   so that we don't free stats structure.

Acked-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Nicolas Pitre <nico@linaro.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2014-01-17 02:00:43 +01:00
Andreas Schwab a857c0b9e2 cpufreq: Fix wrong time unit conversion
The time spent by a CPU under a given frequency is stored in jiffies unit
in the cpu var cpufreq_stats_table->time_in_state[i], i being the index of
the frequency.

This is what is displayed in the following file on the right column:

     cat /sys/devices/system/cpu/cpuX/cpufreq/stats/time_in_state
     2301000 19835820
     2300000 3172
     [...]

Now cpufreq converts this jiffies unit delta to clock_t before returning it
to the user as in the above file. And that conversion is achieved using the API
cputime64_to_clock_t().

Although it accidentally works on traditional tick based cputime accounting, where
cputime_t maps directly to jiffies, it doesn't work with other types of cputime
accounting such as CONFIG_VIRT_CPU_ACCOUNTING_* where cputime_t can map to nsecs
or any granularity preffered by the architecture.

For example we get a buggy zero delta on full dyntick configurations:

     cat /sys/devices/system/cpu/cpuX/cpufreq/stats/time_in_state
     2301000 0
     2300000 0
     [...]

Fix this with using the proper jiffies_64_t to clock_t conversion.

Reported-and-tested-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-09-10 02:49:46 +02:00
Viresh Kumar d5b73cd870 cpufreq: Use sizeof(*ptr) convetion for computing sizes
Chapter 14 of Documentation/CodingStyle says:

The preferred form for passing a size of a struct is the following:

	p = kmalloc(sizeof(*p), ...);

The alternative form where struct name is spelled out hurts
readability and introduces an opportunity for a bug when the pointer
variable type is changed but the corresponding sizeof that is passed
to a memory allocator is not.

This wasn't followed consistently in drivers/cpufreq, let's make it
more consistent by always following this rule.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-08-07 23:34:10 +02:00