linux/drivers/cpufreq
Viresh Kumar 87549141d5 cpufreq: Stop migrating sysfs files on hotplug
When we hot-unplug a cpu, we remove its sysfs cpufreq directory and if
the outgoing cpu was the owner of policy->kobj earlier then we migrate
the sysfs directory to under another online cpu.

There are few disadvantages this brings:
- Code Complexity
- Slower hotplug/suspend/resume
- sysfs file permissions are reset after all policy->cpus are offlined
- CPUFreq stats history lost after all policy->cpus are offlined
- Special management of sysfs stuff during suspend/resume

To overcome these, this patch modifies the way sysfs directories are
managed:
- Select sysfs kobjects owner while initializing policy and don't change
  it during hotplugs. Track it with kobj_cpu created earlier.

- Create symlinks for all related CPUs (can be offline) instead of
  affected CPUs on policy initialization and remove them only when the
  policy is freed.

- Free policy structure only on the removal of cpufreq-driver and not
  during hotplug/suspend/resume, detected by checking 'struct
  subsys_interface *' (Valid only when called from
  subsys_interface_unregister() while unregistering driver).

Apart from this, special care is taken to handle physical hoplug of CPUs
as we wouldn't remove sysfs links or remove policies on logical
hotplugs. Physical hotplug happens in the following sequence.

Hot removal:
- CPU is offlined first, ~ 'echo 0 >
  /sys/devices/system/cpu/cpuX/online'
- Then its device is removed along with all sysfs files, cpufreq core
  notified with cpufreq_remove_dev() callback from subsys-interface..

Hot addition:
- First the device along with its sysfs files is added, cpufreq core
  notified with cpufreq_add_dev() callback from subsys-interface..
- CPU is onlined, ~ 'echo 1 > /sys/devices/system/cpu/cpuX/online'

We call the same routines with both hotplug and subsys callbacks, and we
sense physical hotplug with cpu_offline() check in subsys callback. We
can handle most of the stuff with regular hotplug callback paths and
add/remove cpufreq sysfs links or free policy from subsys callbacks.

Original-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>
2015-06-11 01:00:42 +02:00
..
acpi-cpufreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
amd_freq_sensitivity.c cpufreq: AMD "frequency sensitivity feedback" powersave bias for ondemand governor 2013-04-10 13:19:26 +02:00
arm_big_little_dt.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
arm_big_little.c cpufreq: arm_big_little: remove compile-time dependency on BIG_LITTLE 2015-05-15 01:53:42 +02:00
arm_big_little.h cpufreq: arm_big_little: free OPP table created during ->init() 2014-12-02 00:01:24 +01:00
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
cpufreq_conservative.c cpufreq: conservative: set requested_freq to policy max when it is over policy max 2013-11-12 23:18:20 +01:00
cpufreq_governor.c cpufreq: governor: remove copy_prev_load from 'struct cpu_dbs_common_info' 2014-06-09 12:58:21 +02:00
cpufreq_governor.h cpufreq: governor: remove copy_prev_load from 'struct cpu_dbs_common_info' 2014-06-09 12:58:21 +02:00
cpufreq_ondemand.c cpufreq: ondemand: Eliminate the deadband effect 2014-07-21 13:43:19 +02:00
cpufreq_opp.c cpufreq / OPP: Fix the order of arguments for kcalloc() 2014-09-08 00:02:58 +02:00
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
cpufreq-dt.c cpufreq-dt: Drop unnecessary check before cpufreq_cooling_unregister() invocation 2015-02-03 23:28:37 +01:00
cpufreq-nforce2.c cpufreq: nforce2: remove DEFINE_PCI_DEVICE_TABLE macro 2014-05-17 01:16:15 +02:00
cpufreq.c cpufreq: Stop migrating sysfs files on hotplug 2015-06-11 01:00:42 +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 cpufreq: add 'freq_table' in struct cpufreq_policy 2014-03-12 01:06:00 +01:00
elanfreq.c cpufreq: Use cpufreq_for_each_* macros for frequency table iteration 2014-04-30 00:06:21 +02:00
exynos4x12-cpufreq.c cpufreq: cpu0: rename driver and internals to 'cpufreq_dt' 2014-10-03 15:37:54 +02:00
exynos4210-cpufreq.c cpufreq: cpu0: rename driver and internals to 'cpufreq_dt' 2014-10-03 15:37:54 +02:00
exynos5250-cpufreq.c cpufreq: cpu0: rename driver and internals to 'cpufreq_dt' 2014-10-03 15:37:54 +02:00
exynos5440-cpufreq.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
exynos-cpufreq.c cpufreq: exynos: Use simple approach to asses if cpu cooling can be used 2015-03-02 10:04:52 +01:00
exynos-cpufreq.h ACPI and power management updates for 3.16-rc1 2014-06-04 08:57:16 -07:00
freq_table.c cpufreq: Introduce new relation for freq selection 2014-07-21 13:43:19 +02:00
gx-suspmod.c cpufreq: Convert existing drivers to use cpufreq_freq_transition_{begin|end} 2014-03-26 16:41:41 +01:00
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: use kzalloc() to allocate memory for cpufreq_frequency_table 2014-04-07 14:43:49 +02:00
imx6q-cpufreq.c Driver core patches for 3.19-rc1 2014-12-14 16:10:09 -08:00
integrator-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
intel_pstate.c intel_pstate: Force setting target pstate when required 2015-06-10 02:08:27 +02:00
Kconfig cpufreq: qoriq: rename the driver 2015-03-18 22:35:16 +01:00
Kconfig.arm cpufreq: arm_big_little: remove compile-time dependency on BIG_LITTLE 2015-05-15 01:53:42 +02:00
Kconfig.powerpc cpufreq: qoriq: rename the driver 2015-03-18 22:35:16 +01:00
Kconfig.x86 cpufreq: Add SFI based cpufreq driver support 2014-12-20 13:37:37 -05:00
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: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
ls1x-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2015-01-23 22:19:15 +01:00
Makefile cpufreq: hisilicon: add acpu driver 2015-04-02 02:24:54 +02:00
maple-cpufreq.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +02:00
omap-cpufreq.c cpufreq: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
p4-clockmod.c cpufreq: create another field .flags in cpufreq_frequency_table 2014-04-07 14:43:50 +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 Update/Remove soon-to-be-dead email address 2014-12-19 12:56:15 -08:00
powernow-k7.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
powernow-k8.c cpufreq: powernow-k8: Suppress checkpatch warnings 2014-05-17 01:27:01 +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 cpu frequency throttling 2015-04-01 23:02:24 +02:00
ppc_cbe_cpufreq_pervasive.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +02:00
ppc_cbe_cpufreq_pmi.c cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +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 cpufreq: powerpc/platforms/cell: move cpufreq driver to drivers/cpufreq 2013-04-10 13:19:26 +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: fix qoriq uniprocessor build 2015-04-11 02:07:28 +02:00
s3c24xx-cpufreq-debugfs.c cpufreq: s3c24xx: move cpufreq driver to drivers/cpufreq 2013-05-20 23:04:28 +09:00
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: drop owner assignment from platform_drivers 2014-10-20 16:20:24 +02:00
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
sfi-cpufreq.c cpufreq: Add SFI based cpufreq driver support 2014-12-20 13:37:37 -05:00
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 Update/Remove soon-to-be-dead email address 2014-12-19 12:56:15 -08:00
speedstep-lib.c cpufreq: speedstep-smi: enable interrupts when waiting 2015-02-12 02:02:52 +01:00
speedstep-lib.h [CPUFREQ] Move x86 drivers to drivers/cpufreq/ 2011-05-19 18:51:07 -04:00
speedstep-smi.c cpufreq: speedstep-smi: enable interrupts when waiting 2015-02-12 02:02:52 +01:00
tegra-cpufreq.c cpufreq: tegra: update comment for clarity 2014-06-10 22:50:50 +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