Commit Graph

175 Commits

Author SHA1 Message Date
Rafael J. Wysocki 08a10002be Merge branch 'pm-cpufreq-sched'
* pm-cpufreq-sched:
  cpufreq: schedutil: Always process remote callback with slow switching
  cpufreq: schedutil: Don't restrict kthread to related_cpus unnecessarily
  cpufreq: Return 0 from ->fast_switch() on errors
  cpufreq: Simplify cpufreq_can_do_remote_dvfs()
  cpufreq: Process remote callbacks from any CPU if the platform permits
  sched: cpufreq: Allow remote cpufreq callbacks
  cpufreq: schedutil: Use unsigned int for iowait boost
  cpufreq: schedutil: Make iowait boost more energy efficient
2017-09-04 00:05:22 +02:00
Rafael J. Wysocki d6344d4b56 cpufreq: Simplify cpufreq_can_do_remote_dvfs()
The if () in cpufreq_can_do_remote_dvfs() is superfluous, so drop
it and simply return the value of the expression under it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-08 17:09:02 +02:00
Viresh Kumar 99d14d0e16 cpufreq: Process remote callbacks from any CPU if the platform permits
On many platforms, CPUs can do DVFS across cpufreq policies. i.e CPU
from policy-A can change frequency of CPUs belonging to policy-B.

This is quite common in case of ARM platforms where we don't
configure any per-cpu register.

Add a flag to identify such platforms and update
cpufreq_can_do_remote_dvfs() to allow remote callbacks if this flag is
set.

Also enable the flag for cpufreq-dt driver which is used only on ARM
platforms currently.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-01 14:24:54 +02:00
Viresh Kumar 674e75411f sched: cpufreq: Allow remote cpufreq callbacks
With Android UI and benchmarks the latency of cpufreq response to
certain scheduling events can become very critical. Currently, callbacks
into cpufreq governors are only made from the scheduler if the target
CPU of the event is the same as the current CPU. This means there are
certain situations where a target CPU may not run the cpufreq governor
for some time.

One testcase to show this behavior is where a task starts running on
CPU0, then a new task is also spawned on CPU0 by a task on CPU1. If the
system is configured such that the new tasks should receive maximum
demand initially, this should result in CPU0 increasing frequency
immediately. But because of the above mentioned limitation though, this
does not occur.

This patch updates the scheduler core to call the cpufreq callbacks for
remote CPUs as well.

The schedutil, ondemand and conservative governors are updated to
process cpufreq utilization update hooks called for remote CPUs where
the remote CPU is managed by the cpufreq policy of the local CPU.

The intel_pstate driver is updated to always reject remote callbacks.

This is tested with couple of usecases (Android: hackbench, recentfling,
galleryfling, vellamo, Ubuntu: hackbench) on ARM hikey board (64 bit
octa-core, single policy). Only galleryfling showed minor improvements,
while others didn't had much deviation.

The reason being that this patch only targets a corner case, where
following are required to be true to improve performance and that
doesn't happen too often with these tests:

- Task is migrated to another CPU.
- The task has high demand, and should take the target CPU to higher
  OPPs.
- And the target CPU doesn't call into the cpufreq governor until the
  next tick.

Based on initial work from Steve Muckle.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-08-01 14:24:53 +02:00
Viresh Kumar fe829ed8ef cpufreq: Add CPUFREQ_NO_AUTO_DYNAMIC_SWITCHING cpufreq driver flag
The policy->transition_latency field is used for multiple purposes
today and its not straight forward at all. This is how it is used:

A. Set the correct transition_latency value.

B. Set it to CPUFREQ_ETERNAL because:
   1. We don't want automatic dynamic switching (with
      ondemand/conservative) to happen at all.
   2. We don't know the transition latency.

This patch handles the B.1. case in a more readable way. A new flag for
the cpufreq drivers is added to disallow use of cpufreq governors which
have dynamic_switching flag set.

All the current cpufreq drivers which are setting transition_latency
unconditionally to CPUFREQ_ETERNAL are updated to use it. They don't
need to set transition_latency anymore.

There shouldn't be any functional change after this patch.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26 00:15:46 +02:00
Viresh Kumar ed4676e254 cpufreq: Replace "max_transition_latency" with "dynamic_switching"
There is no limitation in the ondemand or conservative governors which
disallow the transition_latency to be greater than 10 ms.

The max_transition_latency field is rather used to disallow automatic
dynamic frequency switching for platforms which didn't wanted these
governors to run.

Replace max_transition_latency with a boolean (dynamic_switching) and
check for transition_latency == CPUFREQ_ETERNAL along with that. This
makes it pretty straight forward to read/understand now.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-26 00:15:45 +02:00
Viresh Kumar aa7519af45 cpufreq: Use transition_delay_us for legacy governors as well
The policy->transition_delay_us field is used only by the schedutil
governor currently, and this field describes how fast the driver wants
the cpufreq governor to change CPUs frequency. It should rather be a
common thing across all governors, as it doesn't have any schedutil
dependency here.

Create a new helper cpufreq_policy_transition_delay_us() to get the
transition delay across all governors.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22 02:25:20 +02:00
Viresh Kumar 2d04503632 cpufreq: governor: Drop min_sampling_rate
The cpufreq core and governors aren't supposed to set a limit on how
fast we want to try changing the frequency. This is currently done for
the legacy governors with help of min_sampling_rate.

At worst, we may end up setting the sampling rate to a value lower than
the rate at which frequency can be changed and then one of the CPUs in
the policy will be only changing frequency for ever.

But that is something for the user to decide and there is no need to
have special handling for such cases in the core. Leave it for the user
to figure out.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-07-22 02:25:20 +02:00
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
Len Brown f8475cef90 x86: use common aperfmperf_khz_on_cpu() to calculate KHz using APERF/MPERF
The goal of this change is to give users a uniform and meaningful
result when they read /sys/...cpufreq/scaling_cur_freq
on modern x86 hardware, as compared to what they get today.

Modern x86 processors include the hardware needed
to accurately calculate frequency over an interval --
APERF, MPERF, and the TSC.

Here we provide an x86 routine to make this calculation
on supported hardware, and use it in preference to any
driver driver-specific cpufreq_driver.get() routine.

MHz is computed like so:

MHz = base_MHz * delta_APERF / delta_MPERF

MHz is the average frequency of the busy processor
over a measurement interval.  The interval is
defined to be the time between successive invocations
of aperfmperf_khz_on_cpu(), which are expected to to
happen on-demand when users read sysfs attribute
cpufreq/scaling_cur_freq.

As with previous methods of calculating MHz,
idle time is excluded.

base_MHz above is from TSC calibration global "cpu_khz".

This x86 native method to calculate MHz returns a meaningful result
no matter if P-states are controlled by hardware or firmware
and/or if the Linux cpufreq sub-system is or is-not installed.

When this routine is invoked more frequently, the measurement
interval becomes shorter.  However, the code limits re-computation
to 10ms intervals so that average frequency remains meaningful.

Discerning users are encouraged to take advantage of
the turbostat(8) utility, which can gracefully handle
concurrent measurement intervals of arbitrary length.

Signed-off-by: Len Brown <len.brown@intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-06-27 01:47:32 +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
Rafael J. Wysocki 1b72e7fd30 cpufreq: schedutil: Use policy-dependent transition delays
Make the schedutil governor take the initial (default) value of the
rate_limit_us sysfs attribute from the (new) transition_delay_us
policy parameter (to be set by the scaling driver).

That will allow scaling drivers to make schedutil use smaller default
values of rate_limit_us and reduce the default average time interval
between consecutive frequency changes.

Make intel_pstate set transition_delay_us to 500.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2017-04-17 18:37:27 +02:00
Viresh Kumar 565ebe8073 cpufreq: Fix typos in comments
- s/freqnency/frequency/
- s/accomodating/accommodating/

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04 00:47:59 +01:00
Viresh Kumar 052f573f5c cpufreq: Remove CPUFREQ_START notifier event
Its not used anymore, remove it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04 00:05:30 +01:00
Viresh Kumar f9f41e3ef9 cpufreq: Remove policy create/remove notifiers
Those were added by:

commit fcd7af917a ("cpufreq: stats: handle cpufreq_unregister_driver()
and suspend/resume properly")

but aren't used anymore since:

commit 1aefc75b24 ("cpufreq: stats: Make the stats code non-modular").

Remove them. Also remove the redundant parameter to the respective
routines.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-03 23:59:38 +01:00
Rafael J. Wysocki 30248feff5 cpufreq: Make cpufreq_update_policy() void
The return value of cpufreq_update_policy() is never used, so make
it void.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-11-21 14:35:43 +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
Sergey Senozhatsky c6fe46a79e cpufreq: fix overflow in cpufreq_table_find_index_dl()
'best' is always less or equals to 'pos', so `best - pos' returns
a negative value which is then getting casted to `unsigned int'
and passed to __cpufreq_driver_target()->acpi_cpufreq_target()
for policy->freq_table selection. This results in

 BUG: unable to handle kernel paging request at ffff881019b469f8
 IP: [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq]
 PGD 267f067
 PUD 0

 Oops: 0000 [#1] PREEMPT SMP
 CPU: 6 PID: 70 Comm: kworker/6:1 Not tainted 4.9.0-rc1-next-20161017-dbg-dirty
 Workqueue: events dbs_work_handler
 task: ffff88041b808000 task.stack: ffff88041b810000
 RIP: 0010:[<ffffffffa00356c1>]  [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq]
 RSP: 0018:ffff88041b813c60  EFLAGS: 00010282
 RAX: ffff880419b46a00 RBX: ffff88041b848400 RCX: ffff880419b20f80
 RDX: 00000000001dff38 RSI: 00000000ffffffff RDI: ffff88041b848400
 RBP: ffff88041b813cb0 R08: 0000000000000006 R09: 0000000000000040
 R10: ffffffff8207f9e0 R11: ffffffff8173595b R12: 0000000000000000
 R13: ffff88041f1dff38 R14: 0000000000262900 R15: 0000000bfffffff4
 FS:  0000000000000000(0000) GS:ffff88041f000000(0000) knlGS:0000000000000000
 CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
 CR2: ffff881019b469f8 CR3: 000000041a2d3000 CR4: 00000000001406e0
 Stack:
  ffff88041b813cb0 ffffffff813347f9 ffff88041b813ca0 ffffffff81334663
  ffff88041f1d4bc0 ffff88041b848400 0000000000000000 0000000000000000
  0000000000262900 0000000000000000 ffff88041b813d00 ffffffff813355dc
 Call Trace:
  [<ffffffff813347f9>] ? cpufreq_freq_transition_begin+0xf1/0xfc
  [<ffffffff81334663>] ? get_cpu_idle_time+0x97/0xa6
  [<ffffffff813355dc>] __cpufreq_driver_target+0x3b6/0x44e
  [<ffffffff81336ca3>] cs_dbs_timer+0x11a/0x135
  [<ffffffff81336fda>] dbs_work_handler+0x39/0x62
  [<ffffffff81057823>] process_one_work+0x280/0x4a5
  [<ffffffff81058719>] worker_thread+0x24f/0x397
  [<ffffffff810584ca>] ? rescuer_thread+0x30b/0x30b
  [<ffffffff81418380>] ? nl80211_get_key+0x29/0x36a
  [<ffffffff8105d2b7>] kthread+0xfc/0x104
  [<ffffffff8107ceea>] ? put_lock_stats.isra.9+0xe/0x20
  [<ffffffff8105d1bb>] ? kthread_create_on_node+0x3f/0x3f
  [<ffffffff814b2092>] ret_from_fork+0x22/0x30
 Code: 56 4d 6b ff 0c 41 55 41 54 53 48 83 ec 28 48 8b 15 ad 1e 00 00 44 8b 41
 08 48 8b 87 c8 00 00 00 49 89 d5 4e 03 2c c5 80 b2 78 81 <46> 8b 74 38 04 45
 3b 75 00 75 11 31 c0 83 39 00 0f 84 1c 01 00
 RIP  [<ffffffffa00356c1>] acpi_cpufreq_target+0x4f/0x190 [acpi_cpufreq]
  RSP <ffff88041b813c60>
 CR2: ffff881019b469f8
 ---[ end trace 16d9fc7a17897d37 ]---

[ rjw: In some cases this bug may also cause incorrect frequencies to
  be selected by cpufreq governors. ]

Fixes: 899bb6642f (cpufreq: skip invalid entries when searching the frequency)
Link: http://marc.info/?l=linux-kernel&m=147672030714331&w=2
Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reported-and-tested-by: Jörg Otte <jrg.otte@gmail.com>
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.8+ <stable@vger.kernel.org> # 4.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-10-20 16:35:50 +02:00
Aaro Koskinen 899bb6642f cpufreq: skip invalid entries when searching the frequency
Skip invalid entries when searching the frequency. This fixes cpufreq
at least on loongson2 MIPS board.

Fixes: da0c6dc00c (cpufreq: Handle sorted frequency tables more efficiently)
Signed-off-by: Aaro Koskinen <aaro.koskinen@iki.fi>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: 4.8+ <stable@vger.kernel.org> # 4.8+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-10-12 21:01:18 +02:00
Steve Muckle e3c0623608 cpufreq: add cpufreq_driver_resolve_freq()
Cpufreq governors may need to know what a particular target frequency
maps to in the driver without necessarily wanting to set the frequency.
Support this operation via a new cpufreq API,
cpufreq_driver_resolve_freq(). This API returns the lowest driver
frequency equal or greater than the target frequency
(CPUFREQ_RELATION_L), subject to any policy (min/max) or driver
limitations. The mapping is also cached in the policy so that a
subsequent fast_switch operation can avoid repeating the same lookup.

The API will call a new cpufreq driver callback, resolve_freq(), if it
has been registered by the driver. Otherwise the frequency is resolved
via cpufreq_frequency_table_target(). Rather than require ->target()
style drivers to provide a resolve_freq() callback it is left to the
caller to ensure that the driver implements this callback if necessary
to use cpufreq_driver_resolve_freq().

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Steve Muckle <smuckle@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-07-21 14:46:08 +02:00
Viresh Kumar da0c6dc00c cpufreq: Handle sorted frequency tables more efficiently
cpufreq drivers aren't required to provide a sorted frequency table
today, and even the ones which provide a sorted table aren't handled
efficiently by cpufreq core.

This patch adds infrastructure to verify if the freq-table provided by
the drivers is sorted or not, and use efficient helpers if they are
sorted.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-07-07 00:13:20 +02:00
Viresh Kumar d218ed7739 cpufreq: Return index from cpufreq_frequency_table_target()
This routine can't fail unless the frequency table is invalid and
doesn't contain any valid entries.

Make it return the index and WARN() in case it is used for an invalid
table.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-06-09 00:58:06 +02:00
Viresh Kumar 7ab4aabbaa cpufreq: Drop freq-table param to cpufreq_frequency_table_target()
The policy already has this pointer set, use it instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-06-09 00:58:06 +02:00
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
Rafael J. Wysocki 9a15fb2c79 cpufreq: Drop the 'initialized' field from struct cpufreq_governor
The 'initialized' field in struct cpufreq_governor is only used by
the conservative governor (as a usage counter) and the way that
happens is far from straightforward and arguably incorrect.

Namely, the value of 'initialized' is checked by
cpufreq_dbs_governor_init() and cpufreq_dbs_governor_exit() and
the results of those checks are passed (as the second argument) to
the ->init() and ->exit() callbacks in struct dbs_governor.  Those
callbacks are only implemented by the ondemand and conservative
governors and ondemand doesn't use their second argument at all.
In turn, the conservative governor uses it to decide whether or not
to either register or unregister a transition notifier.

That whole mechanism is not only unnecessarily convoluted, but also
racy, because the 'initialized' field of struct cpufreq_governor is
updated in cpufreq_init_governor() and cpufreq_exit_governor() under
policy->rwsem which doesn't help if one of these functions is run
twice in parallel for different policies (which isn't impossible in
principle), for example.

Instead of it, add a proper usage counter to the conservative
governor and update it from cs_init() and cs_exit() which is
guaranteed to be non-racy, as those functions are only called
under gov_dbs_data_mutex which is global.

With that in place, drop the 'initialized' field from struct
cpufreq_governor as it is not used any more.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-06-02 23:24:39 +02:00
Viresh Kumar bf2be2de84 cpufreq: governor: Create cpufreq_policy_apply_limits()
Create a new helper to avoid code duplication across governors.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-06-02 23:24:39 +02:00
Rafael J. Wysocki e788892ba3 cpufreq: governor: Get rid of governor events
The design of the cpufreq governor API is not very straightforward,
as struct cpufreq_governor provides only one callback to be invoked
from different code paths for different purposes.  The purpose it is
invoked for is determined by its second "event" argument, causing it
to act as a "callback multiplexer" of sorts.

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

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

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-06-02 23:24:15 +02:00
Rafael J. Wysocki 6c9d9c8192 cpufreq: Call cpufreq_disable_fast_switch() in sugov_exit()
Due to differences in the cpufreq core's handling of runtime CPU
offline and nonboot CPUs disabling during system suspend-to-RAM,
fast frequency switching gets disabled after a suspend-to-RAM and
resume cycle on all of the nonboot CPUs.

To prevent that from happening, move the invocation of
cpufreq_disable_fast_switch() from cpufreq_exit_governor() to
sugov_exit(), as the schedutil governor is the only user of fast
frequency switching today anyway.

That simply prevents cpufreq_disable_fast_switch() from being called
without invoking the ->governor callback for the CPUFREQ_GOV_POLICY_EXIT
event (which happens during system suspend now).

Fixes: b7898fda5b (cpufreq: Support for fast frequency switching)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-04-08 22:41:36 +02:00
Rafael J. Wysocki b7898fda5b cpufreq: Support for fast frequency switching
Modify the ACPI cpufreq driver to provide a method for switching
CPU frequencies from interrupt context and update the cpufreq core
to support that method if available.

Introduce a new cpufreq driver callback, ->fast_switch, to be
invoked for frequency switching from interrupt context by (future)
governors supporting that feature via (new) helper function
cpufreq_driver_fast_switch().

Add two new policy flags, fast_switch_possible, to be set by the
cpufreq driver if fast frequency switching can be used for the
given policy and fast_switch_enabled, to be set by the governor
if it is going to use fast frequency switching for the given
policy.  Also add a helper for setting the latter.

Since fast frequency switching is inherently incompatible with
cpufreq transition notifiers, make it possible to set the
fast_switch_enabled only if there are no transition notifiers
already registered and make the registration of new transition
notifiers fail if fast_switch_enabled is set for at least one
policy.

Implement the ->fast_switch callback in the ACPI cpufreq driver
and make it set fast_switch_possible during policy initialization
as appropriate.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-04-02 01:09:03 +02:00
Rafael J. Wysocki 379480d825 cpufreq: Move governor symbols to cpufreq.h
Move definitions of symbols related to transition latency and
sampling rate to include/linux/cpufreq.h so they can be used by
(future) goverernors located outside of drivers/cpufreq/.

No functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-04-02 01:09:02 +02:00
Rafael J. Wysocki 66893b6ac9 cpufreq: Move governor attribute set headers to cpufreq.h
Move definitions and function headers related to struct gov_attr_set
to include/linux/cpufreq.h so they can be used by (future) goverernors
located outside of drivers/cpufreq/.

No functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-04-02 01:09:02 +02:00
Rafael J. Wysocki a5acbfbd70 Merge branch 'pm-cpufreq-governor' into pm-cpufreq 2016-03-10 20:46:03 +01:00
Rafael J. Wysocki adaf9fcd13 cpufreq: Move scheduler-related code to the sched directory
Create cpufreq.c under kernel/sched/ and move the cpufreq code
related to the scheduler to that file and to sched.h.

Redefine cpufreq_update_util() as a static inline function to avoid
function calls at its call sites in the scheduler code (as suggested
by Peter Zijlstra).

Also move the definition of struct update_util_data and declaration
of cpufreq_set_update_util_data() from include/linux/cpufreq.h to
include/linux/sched.h.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
2016-03-10 20:44:47 +01:00
Viresh Kumar 242aa883a6 cpufreq: Remove 'policy->governor_enabled'
The entire sequence of events (like INIT/START or STOP/EXIT) for which
cpufreq_governor() is called, is guaranteed to be protected by
policy->rwsem now.

The additional checks that were added earlier (as we were forced to drop
policy->rwsem before calling cpufreq_governor() for EXIT event), aren't
required anymore.

Over that, they weren't sufficient really. They just take care of
START/STOP events, but not INIT/EXIT and the state machine was never
maintained properly by them.

Kill the unnecessary checks and policy->governor_enabled field.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-03-09 14:41:12 +01:00
Viresh Kumar 68e80dae09 Revert "cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT"
Earlier, when the struct freq-attr was used to represent governor
attributes, the standard cpufreq show/store sysfs attribute callbacks
were applied to the governor tunable attributes and they always acquire
the policy->rwsem lock before carrying out the operation.  That could
have resulted in an ABBA deadlock if governor tunable attributes are
removed under policy->rwsem while one of them is being accessed
concurrently (if sysfs attributes removal wins the race, it will wait
for the access to complete with policy->rwsem held while the attribute
callback will block on policy->rwsem indefinitely).

We attempted to address this issue by dropping policy->rwsem around
governor tunable attributes removal (that is, around invocations of the
->governor callback with the event arg equal to CPUFREQ_GOV_POLICY_EXIT)
in cpufreq_set_policy(), but that opened up race conditions that had not
been possible with policy->rwsem held all the time.

The previous commit, "cpufreq: governor: New sysfs show/store callbacks
for governor tunables", fixed the original ABBA deadlock by adding new
governor specific show/store callbacks.

We don't have to drop rwsem around invocations of governor event
CPUFREQ_GOV_POLICY_EXIT anymore, and original fix can be reverted now.

Fixes: 955ef48335 (cpufreq: Drop rwsem lock around CPUFREQ_GOV_POLICY_EXIT)
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reported-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Juri Lelli <juri.lelli@arm.com>
Tested-by: Shilpasri G Bhat <shilpa.bhat@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2016-03-09 14:40:59 +01:00
Rafael J. Wysocki 34e2c555f3 cpufreq: Add mechanism for registering utilization update callbacks
Introduce a mechanism by which parts of the cpufreq subsystem
("setpolicy" drivers or the core) can register callbacks to be
executed from cpufreq_update_util() which is invoked by the
scheduler's update_load_avg() on CPU utilization changes.

This allows the "setpolicy" drivers to dispense with their timers
and do all of the computations they need and frequency/voltage
adjustments in the update_load_avg() code path, among other things.

The update_load_avg() changes were suggested by Peter Zijlstra.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
2016-03-09 14:39:19 +01:00
Rafael J. Wysocki 34b0870515 cpufreq: Simplify the cpufreq_for_each_valid_entry()
That macro uses an internal static inline function that is first
totally unnecessary and second hard to read, so simplify it and
get rid of that monster.

No functional changes.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-02-26 22:11:56 +01:00
Rafael J. Wysocki de1df26b7c cpufreq: Clean up default and fallback governor setup
The preprocessor magic used for setting the default cpufreq governor
(and for using the performance governor as a fallback one for that
matter) is really nasty, so replace it with __weak functions and
overrides.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-02-05 02:37:42 +01:00
Rafael J. Wysocki 7a6c79f2fe cpufreq: Simplify core code related to boost support
Notice that the boost_supported field in struct cpufreq_driver is
redundant, because the driver's ->set_boost callback may be left
unset if "boost" is not supported.  Moreover, the only driver
populating the ->set_boost callback is acpi_cpufreq, so make it
avoid populating that callback if "boost" is not supported, rework
the core to check ->set_boost instead of boost_supported to
verify "boost" support and drop boost_supported which isn't
used any more.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-01-01 03:49:51 +01:00
Rafael J. Wysocki 41669da030 cpufreq: Make cpufreq_boost_supported() static
cpufreq_boost_supported() is not used outside of cpufreq.c, so make
it static.

While at it, refactor it as a one-liner (which it really is).

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2016-01-01 03:49:51 +01:00
Srinivas Pandruvada 69030dd1c3 cpufreq: use last policy after online for drivers with ->setpolicy
For cpufreq drivers which use setpolicy interface, after offline->online
the policy is set to default. This can be reproduced by setting the
default policy of intel_pstate or longrun to ondemand and then change to
"performance". After offline and online, the setpolicy will be called with
the policy=ondemand.

For drivers using governors this condition is handled by storing
last_governor, during offline and restoring during online. The same should
be done for drivers using setpolicy interface. Storing last_policy during
offline and restoring during online.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-12-02 23:50:33 +01:00
Viresh Kumar 96bdda61f5 cpufreq: create cpu/cpufreq/policyX directories
The cpufreq sysfs interface had been a bit inconsistent as one of the
CPUs for a policy had a real directory within its sysfs 'cpuX' directory
and all other CPUs had links to it. That also made the code a bit
complex as we need to take care of moving the sysfs directory if the CPU
containing the real directory is getting physically hot-unplugged.

Solve this by creating 'policyX' directories (per-policy) in
/sys/devices/system/cpu/cpufreq/ directory, where X is the CPU for which
the policy was first created.

This also removes the need of keeping kobj_cpu and we can remove it now.

Suggested-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Saravana Kannan <skannan@codeaurora.org>
Acked-by: is more of a general agreement from the person that he is
Reviewed-by: is a more strict tag and implies that the reviewer has
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-28 09:21:12 +01:00
Viresh Kumar c82bd44437 cpufreq: remove cpufreq_sysfs_{create|remove}_file()
They don't do anything special now, remove the unnecessary wrapper.

Reviewed-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-28 09:21:12 +01:00
Viresh Kumar 8eec1020f0 cpufreq: create cpu/cpufreq at boot time
Later patches will need to create policy specific directories in
/sys/devices/system/cpu/cpufreq/ directory and so the cpufreq directory
wouldn't be ever empty.

And so no fun creating/destroying it on need basis anymore. Create it
once on system boot.

Reviewed-by: Saravana Kannan <skannan@codeaurora.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-10-28 09:21:12 +01:00
Rafael J. Wysocki 1f0bd44e93 cpufreq: acpi-cpufreq: Use cpufreq_cpu_get_raw() in ->get()
cpufreq_cpu_get() called by get_cur_freq_on_cpu() is overkill,
because the ->get() callback is always invoked in a context in
which all of the conditions checked by cpufreq_cpu_get() are
guaranteed to be satisfied.

Use cpufreq_cpu_get_raw() instead of it and drop the
corresponding cpufreq_cpu_put() from get_cur_freq_on_cpu().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
2015-09-16 02:17:49 +02:00
Rafael J. Wysocki ac2a29c8a4 Merge branch 'pm-opp'
* pm-opp:
  PM / OPP: Drop unlikely before IS_ERR(_OR_NULL)
  PM / OPP: Fix static checker warning (broken 64bit big endian systems)
  PM / OPP: Free resources and properly return error on failure
  cpufreq-dt: make scaling_boost_freqs sysfs attr available when boost is enabled
  cpufreq: dt: Add support for turbo/boost mode
  cpufreq: dt: Add support for operating-points-v2 bindings
  cpufreq: Allow drivers to enable boost support after registering driver
  cpufreq: Update boost flag while initializing freq table from OPPs
  PM / OPP: add dev_pm_opp_is_turbo() helper
  PM / OPP: Add helpers for initializing CPU OPPs
  PM / OPP: Add support for opp-suspend
  PM / OPP: Add OPP sharing information to OPP library
  PM / OPP: Add clock-latency-ns support
  PM / OPP: Add support to parse "operating-points-v2" bindings
  PM / OPP: Break _opp_add_dynamic() into smaller functions
  PM / OPP: Allocate dev_opp from _add_device_opp()
  PM / OPP: Create _remove_device_opp() for freeing dev_opp
  PM / OPP: Relocate few routines
  PM / OPP: Create a directory for opp bindings
  PM / OPP: Update bindings to make opp-hz a 64 bit value
2015-09-01 15:52:41 +02:00
Viresh Kumar c7a7b418dd cpufreq: rename cpufreq_real_policy as cpufreq_user_policy
Its all about caching min/max freq requested by userspace, and
the name 'cpufreq_real_policy' doesn't fit that well. Rename it to
cpufreq_user_policy.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-09-01 15:50:39 +02:00
Viresh Kumar 88dc438495 cpufreq: remove redundant 'policy' field from user_policy
Its always same as policy->policy, and there is no need to keep another
copy of it. Remove it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-09-01 15:50:39 +02:00
Viresh Kumar e27f8bd248 cpufreq: remove redundant 'governor' field from user_policy
Its always same as policy->governor, and there is no need to keep
another copy of it. Remove it.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-09-01 15:50:39 +02:00