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linux-stable/drivers/cpufreq
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Viresh Kumar 70f43e5e79 cpufreq: governor: replace per-CPU delayed work with timers 
cpufreq governors evaluate load at sampling rate and based on that they
update frequency for a group of CPUs belonging to the same cpufreq
policy.

This is required to be done in a single thread for all policy->cpus, but
because we don't want to wakeup idle CPUs to do just that, we use
deferrable work for this. If we would have used a single delayed
deferrable work for the entire policy, there were chances that the CPU
required to run the handler can be in idle and we might end up not
changing the frequency for the entire group with load variations.

And so we were forced to keep per-cpu works, and only the one that
expires first need to do the real work and others are rescheduled for
next sampling time.

We have been using the more complex solution until now, where we used a
delayed deferrable work for this, which is a combination of a timer and
a work.

This could be made lightweight by keeping per-cpu deferred timers with a
single work item, which is scheduled by the first timer that expires.

This patch does just that and here are important changes:
- The timer handler will run in irq context and so we need to use a
  spin_lock instead of the timer_mutex. And so a separate timer_lock is
  created. This also makes the use of the mutex and lock quite clear, as
  we know what exactly they are protecting.
- A new field 'skip_work' is added to track when the timer handlers can
  queue a work. More comments present in code.

Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2015-12-09 22:26:00 +01:00
..
acpi-cpufreq.c cpufreq: acpi_cpufreq: prevent crash on reading freqdomain_cpus 2015-10-08 21:47:13 +02:00
amd_freq_sensitivity.c
arm_big_little.c cpufreq: arm_big_little: fix frequency check when bL switcher is active 2015-11-02 01:58:27 +01:00
arm_big_little.h PM / OPP: Prefix exported opp routines with dev_pm_opp_ 2015-09-15 02:03:16 +02:00
arm_big_little_dt.c PM / OPP: Prefix exported opp routines with dev_pm_opp_ 2015-09-15 02:03:16 +02:00
at32ap-cpufreq.c cpufreq: at32ap: don't declare local variable as static 2014-04-07 14:31:33 +02:00
blackfin-cpufreq.c cpufreq: Remove cpufreq_generic_exit() 2014-03-12 01:06:00 +01:00
cppc_cpufreq.c cpufreq: CPPC: Initialize and check CPUFreq CPU co-ord type correctly 2015-11-23 22:21:18 +01:00
cpufreq-dt.c PM / OPP: Prefix exported opp routines with dev_pm_opp_ 2015-09-15 02:03:16 +02:00
cpufreq-nforce2.c cpufreq: nforce2: Fix typo in comment to function nforce2_init() 2015-06-15 15:45:24 +02:00
cpufreq.c cpufreq: use last policy after online for drivers with ->setpolicy 2015-12-02 23:50:33 +01:00
cpufreq_conservative.c cpufreq: governor: Pass policy as argument to ->gov_dbs_timer() 2015-12-07 02:20:22 +01:00
cpufreq_governor.c cpufreq: governor: replace per-CPU delayed work with timers 2015-12-09 22:26:00 +01:00
cpufreq_governor.h cpufreq: governor: replace per-CPU delayed work with timers 2015-12-09 22:26:00 +01:00
cpufreq_ondemand.c cpufreq: governor: replace per-CPU delayed work with timers 2015-12-09 22:26:00 +01:00
cpufreq_performance.c cpufreq: Clean up header files included in the core 2013-08-07 23:34:09 +02:00
cpufreq_powersave.c cpufreq: Clean up header files included in the core 2013-08-07 23:34:09 +02:00
cpufreq_stats.c cpufreq: stats: drop unnecessary locking 2015-01-23 23:06:45 +01:00
cpufreq_userspace.c cpufreq / governor: Remove fossil comment 2013-10-17 23:00:20 +02:00
cris-artpec3-cpufreq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
cris-etraxfs-cpufreq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
davinci-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
dbx500-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
e_powersaver.c ACPI / processor: Drop an unused argument of a cleanup routine 2015-07-22 22:11:16 +02:00
elanfreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
exynos5440-cpufreq.c PM / OPP: Prefix exported opp routines with dev_pm_opp_ 2015-09-15 02:03:16 +02:00
freq_table.c cpufreq: Allow drivers to enable boost support after registering driver 2015-08-07 03:25:23 +02:00
gx-suspmod.c cpufreq: gx-suspmod: Fix two typos in two comments 2015-06-15 15:46:15 +02:00
highbank-cpufreq.c Merge branch 'mailbox-for-linus' of git://git.linaro.org/landing-teams/working/fujitsu/integration 2014-10-21 11:21:19 -07:00
hisi-acpu-cpufreq.c cpufreq: hisilicon: add acpu driver 2015-04-02 02:24:54 +02:00
ia64-acpi-cpufreq.c cpufreq: ia64: Fix a memory leak in acpi_cpufreq_cpu_exit() 2015-07-22 22:27:40 +02:00
imx6q-cpufreq.c Merge branch 'pm-opp' 2015-11-02 00:54:37 +01:00
integrator-cpufreq.c cpufreq: integrator: Fix module autoload for OF platform driver 2015-09-25 23:29:35 +02:00
intel_pstate.c intel_pstate: Fix "performance" mode behavior with HWP enabled 2015-11-25 23:37:44 +01:00
Kconfig cpufreq: qoriq: rename the driver 2015-03-18 22:35:16 +01:00
Kconfig.arm cpufreq: SCPI: Depend on SCPI clk driver 2015-11-23 23:50:27 +01:00
Kconfig.powerpc cpufreq: qoriq: rename the driver 2015-03-18 22:35:16 +01:00
Kconfig.x86 Revert "cpufreq: intel_pstate: Use ACPI perf configuration" 2015-11-19 00:20:42 +01:00
kirkwood-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
longhaul.c Update/Remove soon-to-be-dead email address 2014-12-19 12:56:15 -08:00
longhaul.h cpufreq: delete __cpuinit usage from all cpufreq files 2013-07-14 19:36:57 -04:00
longrun.c cpufreq: add new routine cpufreq_verify_within_cpu_limits() 2013-10-16 00:50:23 +02:00
loongson2_cpufreq.c CPUFREQ: Loongson2: Fix broken build due to incorrect include. 2015-08-03 09:24:59 +02:00
ls1x-cpufreq.c MIPS: Loongson: Naming style cleanup and rework 2015-06-21 21:53:59 +02:00
Makefile ARM: SoC driver updates for v4.4 2015-11-10 15:00:03 -08:00
maple-cpufreq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
mt8173-cpufreq.c PM / OPP: Prefix exported opp routines with dev_pm_opp_ 2015-09-15 02:03:16 +02:00
omap-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
p4-clockmod.c p4-clockmod: Replace cpu_sibling_mask() with topology_sibling_cpumask() 2015-05-27 15:22:16 +02:00
pasemi-cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
pcc-cpufreq.c cpufreq: pcc: Enable autoload of pcc-cpufreq for ACPI processors 2014-11-14 00:16:25 +01:00
pmac32-cpufreq.c powerpc: Remove powerpc specific cmd_line 2014-10-02 17:33:55 +10:00
pmac64-cpufreq.c of: Migrate of_find_node_by_name() users to for_each_node_by_name() 2014-06-26 17:12:24 +01:00
powernow-k6.c Update/Remove soon-to-be-dead email address 2014-12-19 12:56:15 -08:00
powernow-k7.c ACPI / processor: Drop an unused argument of a cleanup routine 2015-07-22 22:11:16 +02:00
powernow-k7.h
powernow-k8.c ACPI / processor: Drop an unused argument of a cleanup routine 2015-07-22 22:11:16 +02:00
powernow-k8.h cpufreq: powernow-k8: Suppress checkpatch warnings 2014-05-17 01:27:01 +02:00
powernv-cpufreq.c cpufreq : powernv: Report Pmax throttling if capped below nominal frequency 2015-09-26 03:03:06 +02:00
ppc_cbe_cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
ppc_cbe_cpufreq.h
ppc_cbe_cpufreq_pervasive.c
ppc_cbe_cpufreq_pmi.c cpufreq: remove redundant CPUFREQ_INCOMPATIBLE notifier event 2015-09-01 15:50:38 +02:00
pxa2xx-cpufreq.c cpufreq: pxa: make pxa_freqs arrays const 2015-05-05 00:49:38 +02:00
pxa3xx-cpufreq.c cpufreq: Remove cpufreq_generic_exit() 2014-03-12 01:06:00 +01:00
qoriq-cpufreq.c cpufreq: qoriq: optimize the CPU frequency switching time 2015-06-15 15:47:28 +02:00
s3c24xx-cpufreq-debugfs.c
s3c24xx-cpufreq.c cpufreq: s3c: remove last use of resume_clocks callback 2015-02-19 06:36:53 +01:00
s3c64xx-cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
s3c2410-cpufreq.c cpufreq: s3c24xx: Remove some dead code 2014-07-19 04:24:59 +09:00
s3c2412-cpufreq.c cpufreq: s3c24xx: Remove some dead code 2014-07-19 04:24:59 +09:00
s3c2416-cpufreq.c cpufreq: s3c: remove incorrect __init annotations 2015-02-19 06:36:53 +01:00
s3c2440-cpufreq.c cpufreq: s3c24xx: Remove some dead code 2014-07-19 04:24:59 +09:00
s5pv210-cpufreq.c cpufreq: s5pv210-cpufreq: fix wrong do_div() usage 2015-11-05 22:50:48 +01:00
sa1100-cpufreq.c cpufreq: Mark ARM drivers with CPUFREQ_NEED_INITIAL_FREQ_CHECK flag 2014-01-06 14:17:25 +01:00
sa1110-cpufreq.c cpufreq: sa1110: set memory type for h3600 2014-07-16 14:30:17 +02:00
sc520_freq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
scpi-cpufreq.c cpufreq: arm_big_little: add SCPI interface driver 2015-09-28 11:53:38 +01:00
sfi-cpufreq.c cpufreq: sfi: use kmemdup rather than duplicating its implementation 2015-09-01 15:51:15 +02:00
sh-cpufreq.c cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end} 2014-03-26 16:41:41 +01:00
sparc-us2e-cpufreq.c cpufreq: add 'freq_table' in struct cpufreq_policy 2014-03-12 01:06:00 +01:00
sparc-us3-cpufreq.c cpufreq: add 'freq_table' in struct cpufreq_policy 2014-03-12 01:06:00 +01:00
spear-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
speedstep-centrino.c cpufreq: Make linux-pm@vger.kernel.org official mailing list 2014-05-01 01:15:32 +02:00
speedstep-ich.c speedstep-ich: Replace cpu_sibling_mask() with topology_sibling_cpumask() 2015-05-27 15:22:16 +02:00
speedstep-lib.c cpufreq: speedstep-lib: Use monotonic clock 2015-09-01 15:51:43 +02:00
speedstep-lib.h
speedstep-smi.c cpufreq: speedstep-smi: enable interrupts when waiting 2015-02-12 02:02:52 +01:00
tegra20-cpufreq.c cpufreq: tegra20: remove superfluous CONFIG_PM ifdefs 2015-09-26 03:00:57 +02:00
tegra124-cpufreq.c cpufreq: Add cpufreq driver for Tegra124 2015-07-16 09:34:09 +02:00
unicore2-cpufreq.c cpufreq: unicore32: replace IS_ERR and PTR_ERR with PTR_ERR_OR_ZERO 2014-04-21 23:42:27 +02:00
vexpress-spc-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00