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  1. 26 10月, 2013 1 次提交
    • V
      cpufreq: Implement light weight ->target_index() routine · 9c0ebcf7
      由 Viresh Kumar 提交于 
      Currently, the prototype of cpufreq_drivers target routines is:

int target(struct cpufreq_policy *policy, unsigned int target_freq,
		unsigned int relation);

And most of the drivers call cpufreq_frequency_table_target() to get a valid
index of their frequency table which is closest to the target_freq. And they
don't use target_freq and relation after that.

So, it makes sense to just do this work in cpufreq core before calling
cpufreq_frequency_table_target() and simply pass index instead. But this can be
done only with drivers which expose their frequency table with cpufreq core. For
others we need to stick with the old prototype of target() until those drivers
are converted to expose frequency tables.

This patch implements the new light weight prototype for target_index() routine.
It looks like this:

int target_index(struct cpufreq_policy *policy, unsigned int index);

CPUFreq core will call cpufreq_frequency_table_target() before calling this
routine and pass index to it. Because CPUFreq core now requires to call routines
present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time.

This also marks target() interface as deprecated. So, that new drivers avoid
using it. And Documentation is updated accordingly.

It also converts existing .target() to newly defined light weight
.target_index() routine for many driver.
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Acked-by: NJesper Nilsson <jesper.nilsson@axis.com>
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Acked-by: NRussell King <linux@arm.linux.org.uk>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Tested-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rjw@rjwysocki.net>
      9c0ebcf7
  3. 16 10月, 2013 5 次提交
  5. 01 10月, 2013 1 次提交
    • V
      cpufreq: Add new helper cpufreq_table_validate_and_show() · 27047a60
      由 Viresh Kumar 提交于 
      Almost every cpufreq driver is required to validate its frequency table with:
cpufreq_frequency_table_cpuinfo() and then expose it to cpufreq core with:
cpufreq_frequency_table_get_attr().

This patch creates another helper routine cpufreq_table_validate_and_show() that
will do both these steps in a single call and will return 0 for success, error
otherwise.

This also fixes potential bugs in cpufreq drivers where people have called
cpufreq_frequency_table_get_attr() before calling
cpufreq_frequency_table_cpuinfo(), as the later may fail.
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      27047a60
  7. 10 9月, 2013 3 次提交
    • R
      Revert "cpufreq: make sure frequency transitions are serialized" · 798282a8
      由 Rafael J. Wysocki 提交于 
      Commit 7c30ed53 (cpufreq: make sure frequency transitions are
serialized) attempted to serialize frequency transitions by
adding checks to the CPUFREQ_PRECHANGE and CPUFREQ_POSTCHANGE
notifications.  However, it assumed that the notifications will
always originate from the driver's .target() callback, but they
also can be triggered by cpufreq_out_of_sync() and that leads to
warnings like this on some systems:

 WARNING: CPU: 0 PID: 14543 at drivers/cpufreq/cpufreq.c:317
 __cpufreq_notify_transition+0x238/0x260()
 In middle of another frequency transition

accompanied by a call trace similar to this one:

 [<ffffffff81720daa>] dump_stack+0x46/0x58
 [<ffffffff8106534c>] warn_slowpath_common+0x8c/0xc0
 [<ffffffff815b8560>] ? acpi_cpufreq_target+0x320/0x320
 [<ffffffff81065436>] warn_slowpath_fmt+0x46/0x50
 [<ffffffff815b1ec8>] __cpufreq_notify_transition+0x238/0x260
 [<ffffffff815b33be>] cpufreq_notify_transition+0x3e/0x70
 [<ffffffff815b345d>] cpufreq_out_of_sync+0x6d/0xb0
 [<ffffffff815b370c>] cpufreq_update_policy+0x10c/0x160
 [<ffffffff815b3760>] ? cpufreq_update_policy+0x160/0x160
 [<ffffffff81413813>] cpufreq_set_cur_state+0x8c/0xb5
 [<ffffffff814138df>] processor_set_cur_state+0xa3/0xcf
 [<ffffffff8158e13c>] thermal_cdev_update+0x9c/0xb0
 [<ffffffff8159046a>] step_wise_throttle+0x5a/0x90
 [<ffffffff8158e21f>] handle_thermal_trip+0x4f/0x140
 [<ffffffff8158e377>] thermal_zone_device_update+0x57/0xa0
 [<ffffffff81415b36>] acpi_thermal_check+0x2e/0x30
 [<ffffffff81415ca0>] acpi_thermal_notify+0x40/0xdc
 [<ffffffff813e7dbd>] acpi_device_notify+0x19/0x1b
 [<ffffffff813f8241>] acpi_ev_notify_dispatch+0x41/0x5c
 [<ffffffff813e3fbe>] acpi_os_execute_deferred+0x25/0x32
 [<ffffffff81081060>] process_one_work+0x170/0x4a0
 [<ffffffff81082121>] worker_thread+0x121/0x390
 [<ffffffff81082000>] ? manage_workers.isra.20+0x170/0x170
 [<ffffffff81088fe0>] kthread+0xc0/0xd0
 [<ffffffff81088f20>] ? flush_kthread_worker+0xb0/0xb0
 [<ffffffff8173582c>] ret_from_fork+0x7c/0xb0
 [<ffffffff81088f20>] ? flush_kthread_worker+0xb0/0xb0

For this reason, revert commit 7c30ed53 along with the fix 266c13d7
(cpufreq: Fix serialization of frequency transitions) on top of it
and we will revisit the serialization problem later.
Reported-by: NAlessandro Bono <alessandro.bono@gmail.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      798282a8
    • S
      cpufreq: Remove temporary fix for race between CPU hotplug and sysfs-writes · 56d07db2
      由 Srivatsa S. Bhat 提交于 
      Commit "cpufreq: serialize calls to __cpufreq_governor()" had been a temporary
and partial solution to the race condition between writing to a cpufreq sysfs
file and taking a CPU offline. Now that we have a proper and complete solution
to that problem, remove the temporary fix.
Signed-off-by: NSrivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      56d07db2
    • V
      cpufreq: serialize calls to __cpufreq_governor() · 19c76303
      由 Viresh Kumar 提交于 
      We can't take a big lock around __cpufreq_governor() as this causes
recursive locking for some cases. But calls to this routine must be
serialized for every policy. Otherwise we can see some unpredictable
events.

For example, consider following scenario:

__cpufreq_remove_dev()
 __cpufreq_governor(policy, CPUFREQ_GOV_STOP);
   policy->governor->governor(policy, CPUFREQ_GOV_STOP);
    cpufreq_governor_dbs()
     case CPUFREQ_GOV_STOP:
      mutex_destroy(&cpu_cdbs->timer_mutex)
      cpu_cdbs->cur_policy = NULL;
  <PREEMPT>
store()
 __cpufreq_set_policy()
  __cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
    policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
     case CPUFREQ_GOV_LIMITS:
      mutex_lock(&cpu_cdbs->timer_mutex); <-- Warning (destroyed mutex)
       if (policy->max < cpu_cdbs->cur_policy->cur) <- cur_policy == NULL

And so store() will eventually result in a crash if cur_policy is
NULL at this point.

Introduce an additional variable which would guarantee serialization
here.
Reported-by: NStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      19c76303
  9. 10 8月, 2013 2 次提交
  11. 08 8月, 2013 3 次提交
  13. 26 7月, 2013 1 次提交
  15. 04 7月, 2013 1 次提交
    • V
      cpufreq: Fix serialization of frequency transitions · 266c13d7
      由 Viresh Kumar 提交于 
      Commit 7c30ed ("cpufreq: make sure frequency transitions are serialized")
interacts poorly with systems that have a single core freqency for all
cores.  On such systems we have a single policy for all cores with
several CPUs.  When we do a frequency transition the governor calls the
pre and post change notifiers which causes cpufreq_notify_transition()
per CPU.  Since the policy is the same for all of them all CPUs after
the first and the warnings added are generated by checking a per-policy
flag the warnings will be triggered for all cores after the first.

Fix this by allowing notifier to be called for n times. Where n is the number of
cpus in policy->cpus.
Reported-and-tested-by: NMark Brown <broonie@linaro.org>
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      266c13d7
  17. 28 6月, 2013 2 次提交
  19. 21 6月, 2013 2 次提交
    • V
      cpufreq: Fix minor formatting issues · bb176f7d
      由 Viresh Kumar 提交于 
      There were a few noticeable formatting issues in core cpufreq code.
This cleans them up to make code look better.  The changes include:
 - Whitespace cleanup.
 - Rearrangements of code.
 - Multiline comments fixes.
 - Formatting changes to fit 80 columns.

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

[rjw: Changelog]
Signed-off-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      bb176f7d
    • X
      cpufreq: Fix governor start/stop race condition · 95731ebb
      由 Xiaoguang Chen 提交于 
      Cpufreq governors' stop and start operations should be carried out
in sequence.  Otherwise, there will be unexpected behavior, like in
the example below.

Suppose there are 4 CPUs and policy->cpu=CPU0, CPU1/2/3 are linked
to CPU0.  The normal sequence is:

 1) Current governor is userspace.  An application tries to set the
    governor to ondemand.  It will call __cpufreq_set_policy() in
    which it will stop the userspace governor and then start the
    ondemand governor.

 2) Current governor is userspace.  The online of CPU3 runs on CPU0.
    It will call cpufreq_add_policy_cpu() in which it will first
    stop the userspace governor, and then start it again.

If the sequence of the above two cases interleaves, it becomes:

 1) Application stops userspace governor
 2)                                  Hotplug stops userspace governor

which is a problem, because the governor shouldn't be stopped twice
in a row.  What happens next is:

 3) Application starts ondemand governor
 4)                                  Hotplug starts a governor

In step 4, the hotplug is supposed to start the userspace governor,
but now the governor has been changed by the application to ondemand,
so the ondemand governor is started once again, which is incorrect.

The solution is to prevent policy governors from being stopped
multiple times in a row.  A governor should only be stopped once for
one policy.  After it has been stopped, no more governor stop
operations should be executed.

Also add a mutex to serialize governor operations.

[rjw: Changelog.  And you owe me a beverage of my choice.]
Signed-off-by: NXiaoguang Chen <chenxg@marvell.com>
Acked-by: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      95731ebb
  21. 04 6月, 2013 1 次提交
  23. 27 5月, 2013 3 次提交
  25. 02 4月, 2013 1 次提交
  27. 01 4月, 2013 2 次提交
    • V
      cpufreq: governor: Implement per policy instances of governors · 4d5dcc42
      由 Viresh Kumar 提交于 
      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: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      4d5dcc42
    • V
      cpufreq: Add per policy governor-init/exit infrastructure · 7bd353a9
      由 Viresh Kumar 提交于 
      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: NViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      7bd353a9
  29. 02 2月, 2013 7 次提交
  31. 15 11月, 2012 3 次提交
  33. 21 3月, 2012 1 次提交
  35. 16 3月, 2012 1 次提交
    • P
      device.h: audit and cleanup users in main include dir · 313162d0
      由 Paul Gortmaker 提交于 
      The <linux/device.h> header includes a lot of stuff, and
it in turn gets a lot of use just for the basic "struct device"
which appears so often.

Clean up the users as follows:

1) For those headers only needing "struct device" as a pointer
in fcn args, replace the include with exactly that.

2) For headers not really using anything from device.h, simply
delete the include altogether.

3) For headers relying on getting device.h implicitly before
being included themselves, now explicitly include device.h

4) For files in which doing #1 or #2 uncovers an implicit
dependency on some other header, fix by explicitly adding
the required header(s).

Any C files that were implicitly relying on device.h to be
present have already been dealt with in advance.

Total removals from #1 and #2: 51.  Total additions coming
from #3: 9.  Total other implicit dependencies from #4: 7.

As of 3.3-rc1, there were 110, so a net removal of 42 gives
about a 38% reduction in device.h presence in include/*
Signed-off-by: NPaul Gortmaker <paul.gortmaker@windriver.com>
      313162d0