Commit graph

725 commits

Author SHA1 Message Date
Saravana Kannan
6249bf152c cpufreq: cpu-boost: Add cpu-boost driver
When certain bursty and important events take place, it might take a while
for the current cpufreq governor to notice the new load and react to it.
That would result in poor user experience. To alleviate this, the cpu-boost
driver boosts the frequency of a CPU for a short duration to maintain good
user experience while the governor catches up.

Specifically, this commit deals with ensuring that when "important" tasks
migrate from a fast CPU to a slow CPU, the frequency of the slow CPU is
boosted to be at least as high as the fast CPU for a short duration.

Since this driver enforces the boost by hooking into standard cpufreq
ADJUST notifiers, it has several advantages:
- More portable across kernel versions where the cpufreq internals might
  have been rewritten.
- Governor agnostic and hence works with multiple governors like
  conservative, ondemand, interactive, etc.
- Does not affect the sampling period/logic of existing governors.
- Can have the boost period adjusted independent of governor sampling
  period.

Change-Id: Ibd814a20043d0aba64ee7637a4a79b9ffa1b0991
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>
2013-11-25 17:14:47 -08:00
Ian Maund
f06163e6d0 msm: reap unused kernel files
This change removes source files from the kernel tree that
were not being used during make. The list of used files
was generated using an annotated make log and was then
compared with new files added since the public release of
kernel version 3.10.00. New files which were added but
not used have been removed from the tree.

A diff was also run to determine the list of files that had
been modified since the release of kernel version 3.10.00.
These files were then scrubbed based on the current kernel
configuration, removing invalid and unused conditionals.

Some files which support planned functionality or are
useful in debugging have been excluded from this reap.

Change-Id: Ia44a224d3cea7bc78dd45e8a8279860d35d4b008
Signed-off-by: Ian Maund <imaund@codeaurora.org>
2013-11-21 17:45:28 -08:00
Minsung Kim
01ae0541f0 cpufreq: interactive: fix show_target_loads and show_above_hispeed_delay
Remove a trailing whitespace from target_loads and above_hispeed_delay. Problem
happens when user-space program tried to restore parameters that saved before
changing parameters. In this case was returned error(EINVAL).

Change-Id: I5a74e3824602cd6f2b74651adda5ec1b627e61e9
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
Git-commit: cf0fad49d17cb8273ce555dd5b7afab67d7923bf
Git-repo: https://android.googlesource.com/kernel/common/
Signed-off-by: Dilip Gudlur <dgudlur@codeaurora.org>
2013-11-18 11:57:24 -08:00
Junjie Wu
aa3edab571 cpufreq: Save and restore user min/max freq for hotplug
In addition to restoring the previous governor after hotplug, restore
min/max frequency set in user_policy.

This patch combines commit:
1) 026cf76c5a2b1b84cbe12b79800f97389abfd589 (android-msm-2.6.35)
   cpufreq: Save and restore min and max frequencies
2) 82a8db17421e475eb662ad83674d4f7a351bc55e (msm-3.4)
   cpufreq: Save user policy min/max instead of policy min/max during
   hotplug

And refactors it to apply cleanly onto the 3.10 kernel.

Change-Id: Id097132765a5487618ca020bae3cc9c9ea791072
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
2013-09-20 23:32:29 -07:00
Stephen Boyd
b6d59d6bfc cpufreq: Don't use smp_processor_id() in preemptible context
Workqueues are preemptible even if works are queued on them with
queue_work_on(). Let's use raw_smp_processor_id() here to silence
the warning.

BUG: using smp_processor_id() in preemptible [00000000] code: kworker/3:2/674
caller is gov_queue_work+0x28/0xb0
CPU: 0 PID: 674 Comm: kworker/3:2 Tainted: G        W    3.10.0 #30
Workqueue: events od_dbs_timer
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c03885a4>] (debug_smp_processor_id+0xbc/0xf0)
[<c03885a4>] (debug_smp_processor_id+0xbc/0xf0) from [<c0635864>] (gov_queue_work+0x28/0xb0)
[<c0635864>] (gov_queue_work+0x28/0xb0) from [<c0635618>] (od_dbs_timer+0x108/0x134)
[<c0635618>] (od_dbs_timer+0x108/0x134) from [<c01aa8f8>] (process_one_work+0x25c/0x444)
[<c01aa8f8>] (process_one_work+0x25c/0x444) from [<c01aaf88>] (worker_thread+0x200/0x344)
[<c01aaf88>] (worker_thread+0x200/0x344) from [<c01b03bc>] (kthread+0xa0/0xb0)
[<c01b03bc>] (kthread+0xa0/0xb0) from [<c01061b8>] (ret_from_fork+0x14/0x3c)

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 17:24:51 -07:00
Stephen Boyd
c43e0a8d13 cpufreq: Fix timer/workqueue corruption due to double queueing
When a CPU is hot removed we'll cancel all the delayed work items
via gov_cancel_work(). Normally this will just cancel a delayed
timer on each CPU that the policy is managing and the work won't
run, but if the work is already running the workqueue code will
wait for the work to finish before continuing to prevent the
work items from re-queuing themselves like they normally do. This
scheme will work most of the time, except for the case where the
work function determines that it should adjust the delay for all
other CPUs that the policy is managing. If this scenario occurs,
the canceling CPU will cancel its own work but queue up the other
CPUs works to run. For example:

 CPU0                                        CPU1
 ----                                        ----
 cpu_down()
  ...
  __cpufreq_remove_dev()
   cpufreq_governor_dbs()
    case CPUFREQ_GOV_STOP:
     gov_cancel_work(dbs_data, policy);
      cpu0 work is canceled
       timer is canceled
       cpu1 work is canceled                    <work runs>
       <waits for cpu1>                         od_dbs_timer()
                                                 gov_queue_work(*, *, true);
 						  cpu0 work queued
 						  cpu1 work queued
						  cpu2 work queued
						  ...
       cpu1 work is canceled
       cpu2 work is canceled
       ...

At the end of the GOV_STOP case cpu0 still has a work queued to
run although the code is expecting all of the works to be
canceled. __cpufreq_remove_dev() will then proceed to
re-initialize all the other CPUs works except for the CPU that is
going down. The CPUFREQ_GOV_START case in cpufreq_governor_dbs()
will trample over the queued work and debugobjects will spit out
a warning:

WARNING: at lib/debugobjects.c:260 debug_print_object+0x94/0xbc()
ODEBUG: init active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x10
Modules linked in:
CPU: 0 PID: 1491 Comm: sh Tainted: G        W    3.10.0 #19
[<c010c178>] (unwind_backtrace+0x0/0x11c) from [<c0109dec>] (show_stack+0x10/0x14)
[<c0109dec>] (show_stack+0x10/0x14) from [<c01904cc>] (warn_slowpath_common+0x4c/0x6c)
[<c01904cc>] (warn_slowpath_common+0x4c/0x6c) from [<c019056c>] (warn_slowpath_fmt+0x2c/0x3c)
[<c019056c>] (warn_slowpath_fmt+0x2c/0x3c) from [<c0388a7c>] (debug_print_object+0x94/0xbc)
[<c0388a7c>] (debug_print_object+0x94/0xbc) from [<c0388e34>] (__debug_object_init+0x2d0/0x340)
[<c0388e34>] (__debug_object_init+0x2d0/0x340) from [<c019e3b0>] (init_timer_key+0x14/0xb0)
[<c019e3b0>] (init_timer_key+0x14/0xb0) from [<c0635f78>] (cpufreq_governor_dbs+0x3e8/0x5f8)
[<c0635f78>] (cpufreq_governor_dbs+0x3e8/0x5f8) from [<c06325a0>] (__cpufreq_governor+0xdc/0x1a4)
[<c06325a0>] (__cpufreq_governor+0xdc/0x1a4) from [<c0633704>] (__cpufreq_remove_dev.isra.10+0x3b4/0x434)
[<c0633704>] (__cpufreq_remove_dev.isra.10+0x3b4/0x434) from [<c08989f4>] (cpufreq_cpu_callback+0x60/0x80)
[<c08989f4>] (cpufreq_cpu_callback+0x60/0x80) from [<c08a43c0>] (notifier_call_chain+0x38/0x68)
[<c08a43c0>] (notifier_call_chain+0x38/0x68) from [<c01938e0>] (__cpu_notify+0x28/0x40)
[<c01938e0>] (__cpu_notify+0x28/0x40) from [<c0892ad4>] (_cpu_down+0x7c/0x2c0)
[<c0892ad4>] (_cpu_down+0x7c/0x2c0) from [<c0892d3c>] (cpu_down+0x24/0x40)
[<c0892d3c>] (cpu_down+0x24/0x40) from [<c0893ea8>] (store_online+0x2c/0x74)
[<c0893ea8>] (store_online+0x2c/0x74) from [<c04519d8>] (dev_attr_store+0x18/0x24)
[<c04519d8>] (dev_attr_store+0x18/0x24) from [<c02a69d4>] (sysfs_write_file+0x100/0x148)
[<c02a69d4>] (sysfs_write_file+0x100/0x148) from [<c0255c18>] (vfs_write+0xcc/0x174)
[<c0255c18>] (vfs_write+0xcc/0x174) from [<c0255f70>] (SyS_write+0x38/0x64)
[<c0255f70>] (SyS_write+0x38/0x64) from [<c0106120>] (ret_fast_syscall+0x0/0x30)

The simplest fix is to check and see if the governor is being
stopped and ignore the all_cpus flag so that only the work that's
being canceled has the chance to re-queue itself.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 17:24:47 -07:00
Steve Muckle
652b447d79 msm: dcvs: gpu minimum frequency levels
System performance is enhanced if the gpu frequency is given a
minimum corresponding to various frequency levels of CPU 0.

Change-Id: Iba168d708524fc8ef164428bb5f4e0631a499342
Signed-off-by: Steve Muckle <smuckle@codeaurora.org>
2013-09-04 15:36:27 -07:00
Abhijeet Dharmapurikar
a7984e7688 msm: dcvs: remove core name
Currently core_name is used to identify which core the dcvs operates on.
Instead use a type and the type num while registration with dcvs and
return an id (dcvs_core_id) upon successfull registration.

The dcvs_core_id is used by the clients of msm_dcvs to call upon its
apis viz. freq_start, freq_stop, msm_dcvs_idle etc.

The dcvs inturn uses the type num passed in at registration time to
invoke apis on the clients viz. set_freq, get_freq, idle_enable.

This further cleans up the internal dcvs add_core and get_core
implementation. One need not pass around the core_name and use the type
instead.

Change-Id: I1736f4befec02249eae969694c7b7696dc9cdb9d
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:40 -07:00
Abhijeet Dharmapurikar
6656d624c6 msm: dcvs: remove idle notification registration
Register the idle enable callback along with the core. The code
becomes cleaner and easy to update.

Importantly, the msm_dcvs_idle driver becomes useless. Remove it
and instead let the msm governor handle idle enabling and disabling.

Change-Id: Ia056b8b1fcca8ebd356fa0484148c3ade54026fc
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:39 -07:00
Abhijeet Dharmapurikar
d078c4f1d1 msm: dcvs: provide frequency set/get callbacks at registration
There is no need to register a separate structure for setting and
getting frequency.

Simply pass function pointers to set and get callbacks when a
core is registered.

While at it rename the msm_dcvs_freq_sink_register/unregister to
msm_dcvs_freq_sink_start/stop to better reflect that those
apis are meant to do.

Change-Id: I0e5bb1fe8d127e5841ee9916dad5c3fd64815228
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:25 -07:00
Abhijeet Dharmapurikar
b420ae3196 msm: dcvs: update dcvs if the governor limits change
We had seen issues where dcvs goes out of sync with the actual
freq the cpu is running at. The root cause was if the userspace
changes the limits on the governor, the governor ends up changing
the frequency without notifying dcvs.

Provide an api for the governor to call dcvs when a frequency change
happens.

Change-Id: Ifb33fac9cdde8535e274b7c91534dc44cc19dbe7
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:24 -07:00
Abhijeet Dharmapurikar
e585b1137c cpufreq: msm: fix race in cpufreq
__cpufreq_driver_target expects to be called with the rw semaphore
held. We are not doing this when the frequency is asked to be changed
by dcvs.

Use cpufreq_driver_target variant of that function which gets the
rw semaphore before setting the frequency.

Change-Id: I67a7d437f68749f43c26b95ae73f436890326019
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:19 -07:00
Abhijeet Dharmapurikar
e2c08a46fc cpufreq: msm: remove gov_mutex from stop
The stop could end up calling set_frequency callback. The set_frequency
callback takes the same gov_mutex lock and we end up in a deadlock.

Fix this by removing the locks around stop.

Change-Id: Ic687d92825f253aa3e23e4bcaf3c96d5879d4b43
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:19 -07:00
Abhijeet Dharmapurikar
2f4ea63bc6 msm: dcvs: Add thermal interfaces
The algorithm needs thermal inputs for all the cores. Create members in
the internal core_info strucutre and platform data/device tree to pass
in the sensors they use.

Update the dcvs code to notify the temperature to TZ.

Change-Id: I96e123eb49cdd564564e5fe12531407406eafa0c
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:18 -07:00
Abhijeet Dharmapurikar
dd87ea3e19 msm: dcvs: rearrange platform data
This change
-removes the use of group id and instead introduces core type
-rearranges platform data, adds energy curve coefficients and power
 parameters
-allow for the energy params to be -ve numbers

The change also mandates updates to the msm8974-gpu.dtsi and the
associated binding documentation.

Also take this opportunity to remove devices for unsupported platform
- 8930 and 8960

Change-Id: Ie8d5a691defb825955b240c1b304e04f0a21499a
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>
2013-09-04 15:25:07 -07:00
Amar Singhal
ee974af4c9 cpufreq: make the "scaling_cur_freq" sysfs entry pollable
Wakeup userspace poll on change of cpu frequency. The userspace
may then take action to change the power/performance
characteristics of the device.

Change-Id: I3030b22084fe7e0143b978a198ddcc579e7d6e83
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 14:47:07 -07:00
Amar Singhal
187dd1a240 cpufreq: Make the "scaling_governor" sysfs node pollable
A userspace module programs different qos-rules depending on the
governor running in the system. Make the governor node
pollable, so that the userspace module can be triggered when
the value of the governor changes.

change-Id: Ic89c77c7d16b0f8954d59a211612e9a8e98a2c28
Signed-off-by: Amar Singhal <asinghal@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 14:47:07 -07:00
Praveen Chidambaram
0fa51886ea msm: dcvs: Add 'msm-dcvs' cpufreq governor
The 'msm-dcvs' CPUFreq governor interfaces the msm_dcvs driver frequency
change requests with the CPUFreq framework.

Change-Id: I950e5b09f568412760d9b022f59f208c6bcb54ce
Signed-off-by: Praveen Chidambaram <pchidamb@codeaurora.org>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 14:47:06 -07:00
Stephen Boyd
38d8910730 Merge branch 'qandroid-3.10' into msm-3.10
* qandroid-3.10: (636 commits)
  netfilter: xt_qtaguid: Protect iface list access with necessary lock
  HID: magicmouse: Fix build warning
  USB: gadget: mtp: Fix OUT endpoint request length usage in read
  USB: gadget: f_mtp: Fix using tx buffer pointer
  msm: Fix race condition in domain lookup
  msm: Add null-pointer checks for domains
  base: sync: increase size of sync_timeline name
  USB: gadget: mtp: Add module parameters for Tx transfer length
  msm: iommu: Lock the genpool allocation
  gpu: ion: fix page offset in dma_buf_kmap()
  gpu: ion: Fix bug in ion_system_heap map_user
  gpu: ion: Only map as much of the vma as the user requested
  gpu: ion: use vmalloc to allocate page array to map kernel
  gpu: ion: Remove dead comments
  gpu: ion: Minimize allocation fallback delay
  mmc: sd: Set the card removed if card detect fails
  gpu: ion: don't fault in individual pages for the CP heap
  gpu: ion: do not ask for compound pages in system heap
  gpu: ion: Modify the system heap to try to allocate large/huge pages
  gpu: ion: Set the dma_address of the sg list at alloc time
  ...

Conflicts:
	arch/arm/Kconfig
	arch/arm/include/asm/hardware/cache-l2x0.h
	arch/arm/mm/cache-l2x0.c
	drivers/mmc/card/block.c
	drivers/usb/gadget/udc-core.c
2013-09-04 14:46:18 -07:00
Xiaoguang Chen
19d5afc535 cpufreq: Fix governor start/stop race condition
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: Xiaoguang Chen <chenxg@marvell.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: 95731ebb114c5f0c028459388560fc2a72fe5049
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 14:44:53 -07:00
Jacob Shin
22658c8250 cpufreq: don't leave stale policy pointer in cdbs->cur_policy
Clear ->cur_policy when stopping a governor, or the ->cur_policy
pointer may be stale on systems with have_governor_per_policy when a
new policy is allocated due to CPU hotplug offline/online.

[rjw: Changelog]
Suggested-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Jacob Shin <jacob.shin@amd.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: 419e172145cf6c51d436a8bf4afcd17511f0ff79
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-09-04 14:44:52 -07:00
Rafael J. Wysocki
5ef7dbef0c cpufreq: Fix cpufreq driver module refcount balance after suspend/resume
Since cpufreq_cpu_put() called by __cpufreq_remove_dev() drops the
driver module refcount, __cpufreq_remove_dev() causes that refcount
to become negative for the cpufreq driver after a suspend/resume
cycle.

This is not the only bad thing that happens there, however, because
kobject_put() should only be called for the policy kobject at this
point if the CPU is not the last one for that policy.

Namely, if the given CPU is the last one for that policy, the
policy kobject's refcount should be 1 at this point, as set by
cpufreq_add_dev_interface(), and only needs to be dropped once for
the kobject to go away.  This actually happens under the cpu == 1
check, so it need not be done before by cpufreq_cpu_put().

On the other hand, if the given CPU is not the last one for that
policy, this means that cpufreq_add_policy_cpu() has been called
at least once for that policy and cpufreq_cpu_get() has been
called for it too.  To balance that cpufreq_cpu_get(), we need to
call cpufreq_cpu_put() in that case.

Thus, to fix the described problem and keep the reference
counters balanced in both cases, move the cpufreq_cpu_get() call
in __cpufreq_remove_dev() to the code path executed only for
CPUs that share the policy with other CPUs.

Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: 3.10+ <stable@vger.kernel.org>
Git-commit: 2a99859932281ed6c2ecdd988855f8f6838f6743
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-08-22 18:09:28 -07:00
Srivatsa S. Bhat
38f70e635d cpufreq: Revert commit 2f7021a8 to fix CPU hotplug regression
commit 2f7021a8 "cpufreq: protect 'policy->cpus' from offlining
during __gov_queue_work()" caused a regression in CPU hotplug,
because it lead to a deadlock between cpufreq governor worker thread
and the CPU hotplug writer task.

Lockdep splat corresponding to this deadlock is shown below:

[   60.277396] ======================================================
[   60.277400] [ INFO: possible circular locking dependency detected ]
[   60.277407] 3.10.0-rc7-dbg-01385-g241fd04-dirty #1744 Not tainted
[   60.277411] -------------------------------------------------------
[   60.277417] bash/2225 is trying to acquire lock:
[   60.277422]  ((&(&j_cdbs->work)->work)){+.+...}, at: [<ffffffff810621b5>] flush_work+0x5/0x280
[   60.277444] but task is already holding lock:
[   60.277449]  (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81042d8b>] cpu_hotplug_begin+0x2b/0x60
[   60.277465] which lock already depends on the new lock.

[   60.277472] the existing dependency chain (in reverse order) is:
[   60.277477] -> #2 (cpu_hotplug.lock){+.+.+.}:
[   60.277490]        [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200
[   60.277503]        [<ffffffff815b6157>] mutex_lock_nested+0x67/0x410
[   60.277514]        [<ffffffff81042cbc>] get_online_cpus+0x3c/0x60
[   60.277522]        [<ffffffff814b842a>] gov_queue_work+0x2a/0xb0
[   60.277532]        [<ffffffff814b7891>] cs_dbs_timer+0xc1/0xe0
[   60.277543]        [<ffffffff8106302d>] process_one_work+0x1cd/0x6a0
[   60.277552]        [<ffffffff81063d31>] worker_thread+0x121/0x3a0
[   60.277560]        [<ffffffff8106ae2b>] kthread+0xdb/0xe0
[   60.277569]        [<ffffffff815bb96c>] ret_from_fork+0x7c/0xb0
[   60.277580] -> #1 (&j_cdbs->timer_mutex){+.+...}:
[   60.277592]        [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200
[   60.277600]        [<ffffffff815b6157>] mutex_lock_nested+0x67/0x410
[   60.277608]        [<ffffffff814b785d>] cs_dbs_timer+0x8d/0xe0
[   60.277616]        [<ffffffff8106302d>] process_one_work+0x1cd/0x6a0
[   60.277624]        [<ffffffff81063d31>] worker_thread+0x121/0x3a0
[   60.277633]        [<ffffffff8106ae2b>] kthread+0xdb/0xe0
[   60.277640]        [<ffffffff815bb96c>] ret_from_fork+0x7c/0xb0
[   60.277649] -> #0 ((&(&j_cdbs->work)->work)){+.+...}:
[   60.277661]        [<ffffffff810ab826>] __lock_acquire+0x1766/0x1d30
[   60.277669]        [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200
[   60.277677]        [<ffffffff810621ed>] flush_work+0x3d/0x280
[   60.277685]        [<ffffffff81062d8a>] __cancel_work_timer+0x8a/0x120
[   60.277693]        [<ffffffff81062e53>] cancel_delayed_work_sync+0x13/0x20
[   60.277701]        [<ffffffff814b89d9>] cpufreq_governor_dbs+0x529/0x6f0
[   60.277709]        [<ffffffff814b76a7>] cs_cpufreq_governor_dbs+0x17/0x20
[   60.277719]        [<ffffffff814b5df8>] __cpufreq_governor+0x48/0x100
[   60.277728]        [<ffffffff814b6b80>] __cpufreq_remove_dev.isra.14+0x80/0x3c0
[   60.277737]        [<ffffffff815adc0d>] cpufreq_cpu_callback+0x38/0x4c
[   60.277747]        [<ffffffff81071a4d>] notifier_call_chain+0x5d/0x110
[   60.277759]        [<ffffffff81071b0e>] __raw_notifier_call_chain+0xe/0x10
[   60.277768]        [<ffffffff815a0a68>] _cpu_down+0x88/0x330
[   60.277779]        [<ffffffff815a0d46>] cpu_down+0x36/0x50
[   60.277788]        [<ffffffff815a2748>] store_online+0x98/0xd0
[   60.277796]        [<ffffffff81452a28>] dev_attr_store+0x18/0x30
[   60.277806]        [<ffffffff811d9edb>] sysfs_write_file+0xdb/0x150
[   60.277818]        [<ffffffff8116806d>] vfs_write+0xbd/0x1f0
[   60.277826]        [<ffffffff811686fc>] SyS_write+0x4c/0xa0
[   60.277834]        [<ffffffff815bbbbe>] tracesys+0xd0/0xd5
[   60.277842] other info that might help us debug this:

[   60.277848] Chain exists of:
  (&(&j_cdbs->work)->work) --> &j_cdbs->timer_mutex --> cpu_hotplug.lock

[   60.277864]  Possible unsafe locking scenario:

[   60.277869]        CPU0                    CPU1
[   60.277873]        ----                    ----
[   60.277877]   lock(cpu_hotplug.lock);
[   60.277885]                                lock(&j_cdbs->timer_mutex);
[   60.277892]                                lock(cpu_hotplug.lock);
[   60.277900]   lock((&(&j_cdbs->work)->work));
[   60.277907]  *** DEADLOCK ***

[   60.277915] 6 locks held by bash/2225:
[   60.277919]  #0:  (sb_writers#6){.+.+.+}, at: [<ffffffff81168173>] vfs_write+0x1c3/0x1f0
[   60.277937]  #1:  (&buffer->mutex){+.+.+.}, at: [<ffffffff811d9e3c>] sysfs_write_file+0x3c/0x150
[   60.277954]  #2:  (s_active#61){.+.+.+}, at: [<ffffffff811d9ec3>] sysfs_write_file+0xc3/0x150
[   60.277972]  #3:  (x86_cpu_hotplug_driver_mutex){+.+...}, at: [<ffffffff81024cf7>] cpu_hotplug_driver_lock+0x17/0x20
[   60.277990]  #4:  (cpu_add_remove_lock){+.+.+.}, at: [<ffffffff815a0d32>] cpu_down+0x22/0x50
[   60.278007]  #5:  (cpu_hotplug.lock){+.+.+.}, at: [<ffffffff81042d8b>] cpu_hotplug_begin+0x2b/0x60
[   60.278023] stack backtrace:
[   60.278031] CPU: 3 PID: 2225 Comm: bash Not tainted 3.10.0-rc7-dbg-01385-g241fd04-dirty #1744
[   60.278037] Hardware name: Acer             Aspire 5741G    /Aspire 5741G    , BIOS V1.20 02/08/2011
[   60.278042]  ffffffff8204e110 ffff88014df6b9f8 ffffffff815b3d90 ffff88014df6ba38
[   60.278055]  ffffffff815b0a8d ffff880150ed3f60 ffff880150ed4770 3871c4002c8980b2
[   60.278068]  ffff880150ed4748 ffff880150ed4770 ffff880150ed3f60 ffff88014df6bb00
[   60.278081] Call Trace:
[   60.278091]  [<ffffffff815b3d90>] dump_stack+0x19/0x1b
[   60.278101]  [<ffffffff815b0a8d>] print_circular_bug+0x2b6/0x2c5
[   60.278111]  [<ffffffff810ab826>] __lock_acquire+0x1766/0x1d30
[   60.278123]  [<ffffffff81067e08>] ? __kernel_text_address+0x58/0x80
[   60.278134]  [<ffffffff810ac6d4>] lock_acquire+0xa4/0x200
[   60.278142]  [<ffffffff810621b5>] ? flush_work+0x5/0x280
[   60.278151]  [<ffffffff810621ed>] flush_work+0x3d/0x280
[   60.278159]  [<ffffffff810621b5>] ? flush_work+0x5/0x280
[   60.278169]  [<ffffffff810a9b14>] ? mark_held_locks+0x94/0x140
[   60.278178]  [<ffffffff81062d77>] ? __cancel_work_timer+0x77/0x120
[   60.278188]  [<ffffffff810a9cbd>] ? trace_hardirqs_on_caller+0xfd/0x1c0
[   60.278196]  [<ffffffff81062d8a>] __cancel_work_timer+0x8a/0x120
[   60.278206]  [<ffffffff81062e53>] cancel_delayed_work_sync+0x13/0x20
[   60.278214]  [<ffffffff814b89d9>] cpufreq_governor_dbs+0x529/0x6f0
[   60.278225]  [<ffffffff814b76a7>] cs_cpufreq_governor_dbs+0x17/0x20
[   60.278234]  [<ffffffff814b5df8>] __cpufreq_governor+0x48/0x100
[   60.278244]  [<ffffffff814b6b80>] __cpufreq_remove_dev.isra.14+0x80/0x3c0
[   60.278255]  [<ffffffff815adc0d>] cpufreq_cpu_callback+0x38/0x4c
[   60.278265]  [<ffffffff81071a4d>] notifier_call_chain+0x5d/0x110
[   60.278275]  [<ffffffff81071b0e>] __raw_notifier_call_chain+0xe/0x10
[   60.278284]  [<ffffffff815a0a68>] _cpu_down+0x88/0x330
[   60.278292]  [<ffffffff81024cf7>] ? cpu_hotplug_driver_lock+0x17/0x20
[   60.278302]  [<ffffffff815a0d46>] cpu_down+0x36/0x50
[   60.278311]  [<ffffffff815a2748>] store_online+0x98/0xd0
[   60.278320]  [<ffffffff81452a28>] dev_attr_store+0x18/0x30
[   60.278329]  [<ffffffff811d9edb>] sysfs_write_file+0xdb/0x150
[   60.278337]  [<ffffffff8116806d>] vfs_write+0xbd/0x1f0
[   60.278347]  [<ffffffff81185950>] ? fget_light+0x320/0x4b0
[   60.278355]  [<ffffffff811686fc>] SyS_write+0x4c/0xa0
[   60.278364]  [<ffffffff815bbbbe>] tracesys+0xd0/0xd5
[   60.280582] smpboot: CPU 1 is now offline

The intention of that commit was to avoid warnings during CPU
hotplug, which indicated that offline CPUs were getting IPIs from the
cpufreq governor's work items.  But the real root-cause of that
problem was commit a66b2e5 (cpufreq: Preserve sysfs files across
suspend/resume) because it totally skipped all the cpufreq callbacks
during CPU hotplug in the suspend/resume path, and hence it never
actually shut down the cpufreq governor's worker threads during CPU
offline in the suspend/resume path.

Reflecting back, the reason why we never suspected that commit as the
root-cause earlier, was that the original issue was reported with
just the halt command and nobody had brought in suspend/resume to the
equation.

The reason for _that_ in turn, as it turns out, is that earlier
halt/shutdown was being done by disabling non-boot CPUs while tasks
were frozen, just like suspend/resume....  but commit cf7df378a
(reboot: migrate shutdown/reboot to boot cpu) which came somewhere
along that very same time changed that logic: shutdown/halt no longer
takes CPUs offline.  Thus, the test-cases for reproducing the bug
were vastly different and thus we went totally off the trail.

Overall, it was one hell of a confusion with so many commits
affecting each other and also affecting the symptoms of the problems
in subtle ways.  Finally, now since the original problematic commit
(a66b2e5) has been completely reverted, revert this intermediate fix
too (2f7021a8), to fix the CPU hotplug deadlock.  Phew!

Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Tested-by: Peter Wu <lekensteyn@gmail.com>
Cc: 3.10+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: e8d05276f236ee6435e78411f62be9714e0b9377
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-08-22 18:09:27 -07:00
Srivatsa S. Bhat
659989d7c1 cpufreq: Revert commit a66b2e to fix suspend/resume regression
commit a66b2e (cpufreq: Preserve sysfs files across suspend/resume)
has unfortunately caused several things in the cpufreq subsystem to
break subtly after a suspend/resume cycle.

The intention of that patch was to retain the file permissions of the
cpufreq related sysfs files across suspend/resume.  To achieve that,
the commit completely removed the calls to cpufreq_add_dev() and
__cpufreq_remove_dev() during suspend/resume transitions.  But the
problem is that those functions do 2 kinds of things:
  1. Low-level initialization/tear-down that are critical to the
     correct functioning of cpufreq-core.
  2. Kobject and sysfs related initialization/teardown.

Ideally we should have reorganized the code to cleanly separate these
two responsibilities, and skipped only the sysfs related parts during
suspend/resume.  Since we skipped the entire callbacks instead (which
also included some CPU and cpufreq-specific critical components),
cpufreq subsystem started behaving erratically after suspend/resume.

So revert the commit to fix the regression.  We'll revisit and address
the original goal of that commit separately, since it involves quite a
bit of careful code reorganization and appears to be non-trivial.

(While reverting the commit, note that another commit f51e1eb
 (cpufreq: Fix cpufreq regression after suspend/resume) already
 reverted part of the original set of changes.  So revert only the
 remaining ones).

Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Tested-by: Paul Bolle <pebolle@tiscali.nl>
Cc: 3.10+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: aae760ed21cd690fe8a6db9f3a177ad55d7e12ab
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-08-22 18:09:26 -07:00
Srivatsa S. Bhat
021bac3da8 cpufreq: Fix cpufreq regression after suspend/resume
Toralf Förster reported that the cpufreq ondemand governor behaves erratically
(doesn't scale well) after a suspend/resume cycle. The problem was that the
cpufreq subsystem's idea of the cpu frequencies differed from the actual
frequencies set in the hardware after a suspend/resume cycle. Toralf bisected
the problem to commit a66b2e5 (cpufreq: Preserve sysfs files across
suspend/resume).

Among other (harmless) things, that commit skipped the call to
cpufreq_update_policy() in the resume path. But cpufreq_update_policy() plays
an important role during resume, because it is responsible for checking if
the BIOS changed the cpu frequencies behind our back and resynchronize the
cpufreq subsystem's knowledge of the cpu frequencies, and update them
accordingly.

So, restore the call to cpufreq_update_policy() in the resume path to fix
the cpufreq regression.

Reported-and-tested-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: 3.10+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: f51e1eb63d9c28cec188337ee656a13be6980cfd
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
2013-08-22 18:09:26 -07:00
Deepak Katragadda
059e669ed2 msm: cpufreq: Only apply driver limits for scaling_min/max_freq writes
When new values are written to scaling_min/max_freq sysfs files, the
current code applies all the limits imposed by various ADJUST and
INCOMPATIBLE notifiers handlers before storing them.

When the ADJUST and/or INCOMPATIBLE notifiers change their limits
frequently, this behavior makes it almost impossible for a
user/userspace process to store the scaling_min/max_freq limits
that go beyond the instantaneous limits imposed by the notifiers.
Since these sysfs nodes are typically meant to set limits that need
to be enforced for the foreseeable future, this is not a very user
friendly behavior.

So, change the behavior to only apply limits that are enforced by
the cpufreq driver. Typically, these are just the absolute limits
of the HW and don't change very often.

Change-Id: I1ccfaa2d1ee4ea595f882485d359dbdb407a0176
Signed-off-by: Deepak Katragadda <dkatraga@codeaurora.org>
2013-08-22 18:08:48 -07:00
Lianwei Wang
37a05ab72b cpufreq: interactive: resched timer if max freq raised
When the policy max freq is raised, and before the timer is
rescheduled in idle callback, the cpu freq may stuck at a
lower freq.

The target_freq shall be updated too, else on a high load
situation, the new_freq is always equal to target_freq and
which will cause freq stuck at a lower freq too.

Reschedule the timer on gov limits callback.

Change-Id: I6c187001ab43e859731429b64f75a74eebc37a24
Signed-off-by: Lianwei Wang <a22439@motorola.com>
2013-07-01 15:46:29 -07:00
Lianwei Wang
e1fb7646f1 cpufreq: interactive: fix race on cpufreq TRANSITION notifier
The cpufreq TRANSTION notifier callback does not check the
governor_enabled state on affected CPUS, which will case
kernel panic in update_load because the policy object maybe
NULL or invalid when governor_enabled is false.

Change-Id: Ie0f1718124f61e2f9b5da57abc6981ada5b83908
Signed-off-by: Lianwei Wang <a22439@motorola.com>
2013-07-01 15:46:28 -07:00
Minsung Kim
3ab74abdc3 cpufreq: interactive: avoid underflow on active time calculation
Check for idle time delta less than elapsed time delta, avoid
underflow computing active time.

Change-Id: I3e4c6ef1ad794eec49ed379c0c50fa727fd6ad28
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
2013-07-01 14:16:27 -07:00
Todd Poynor
d06bc7e5b3 cpufreq: interactive: reduce chance of zero time delta on load eval
Reschedule load sampling timer after timestamp of sample start taken,
hold spinlock across entire sequence to avoid preemption.  Avoid the
WARN for zero time delta in the load sampling timer function.

Change-Id: Idc10a756f09141decb6df92669521a1ebf0dbc10
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:27 -07:00
Todd Poynor
fb07c42ed8 cpufreq: interactive: handle errors from cpufreq_frequency_table_target
Add checks for error return from cpufreq_frequency_table_target, and be
less noisy on the existing call with an error check.  CPU hotplug and
system shutdown may cause this call to return -EINVAL.

Bug: 8613560
Change-Id: Id78d8829920462c0db1c7e14e717d91740d6cb44
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:27 -07:00
Minsung Kim
790fbc3116 cpufreq: interactive: fix uninitialized spinlock
Add missing spinlock init

Backtrace:
[<c0011ce4>] (dump_backtrace+0x0/0x10c) from [<c0662a68>] (dump_stack+0x18/0x1c)
 r6:00000032 r5:c0bd09ec r4:e6848000 r3:00000000
[<c0662a50>] (dump_stack+0x0/0x1c) from [<c06670b0>] (spin_dump+0x80/0x94)
[<c0667030>] (spin_dump+0x0/0x94) from [<c06670f0>] (spin_bug+0x2c/0x30)
 r5:c08f91fc r4:c0bd09ec
[<c06670c4>] (spin_bug+0x0/0x30) from [<c0245f74>] (do_raw_spin_unlock+0x88/0xcc)
 r5:e547bac0 r4:c0bd09ec
[<c0245eec>] (do_raw_spin_unlock+0x0/0xcc) from [<c066c9cc>] (_raw_spin_unlock_irqrestore+0x14/0x40)
 r5:e547bac0 r4:60000013
[<c066c9b8>] (_raw_spin_unlock_irqrestore+0x0/0x40) from [<c044b884>] (store_above_hispeed_delay+0x6c/0x80)
 r4:c0b4cf78 r3:00000007
[<c044b818>] (store_above_hispeed_delay+0x0/0x80) from [<c0235d24>] (kobj_attr_store+0x1c/0x28)
 r7:e68ff000 r6:00000032 r5:e58137c0 r4:e61cde80
[<c0235d08>] (kobj_attr_store+0x0/0x28) from [<c0156b78>] (sysfs_write_file+0x104/0x184)
[<c0156a74>] (sysfs_write_file+0x0/0x184) from [<c0100680>] (vfs_write+0xb0/0x140)
[<c01005d0>] (vfs_write+0x0/0x140) from [<c0100900>] (sys_write+0x44/0x70)
 r8:00000000 r7:00000004 r6:00000032 r5:bee43c90 r4:e5600300
[<c01008bc>] (sys_write+0x0/0x70) from [<c000e400>] (ret_fast_syscall+0x0/0x30)
 r9:e6842000 r8:c000e584 r6:00000032 r5:bee43c90 r4:00000009

Change-Id: I80a1e0b3fecb24adba501ff44f568479deeff7fa
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
2013-07-01 14:16:25 -07:00
Todd Poynor
9b3941d0af cpufreq: interactive: base above_hispeed_delay on target freq, not current
Time to wait should be based on the intended target speed, not the
actual speed (which may be held high by another CPU).

Change-Id: Ifc5bb55d06adddb9a02af90af05398a78f282272
Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:23 -07:00
Todd Poynor
eb58ca7afd cpufreq: interactive: fix crash on error paths in get_tokenized_data
Use separate variable for error code, free proper pointer.

Change-Id: Ia83cccb195997789ac6afbf5b8761f7b278196d6
Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:23 -07:00
Lianwei Wang
fb117edf60 cpufreq: interactive: add io_is_busy interface
Previously the idle time returned from get_cpu_idle_time_us included the
iowait time. So the iowait time was always calculated as idle time.

But now the idle time returned from get_cpu_idle_time_us does not include
the iowait time anymore because of below commit which cause the iowait time
always calculated as busy time:
    6beea0c nohz: Fix update_ts_time_stat idle accounting

Add the io_is_busy interface, as does the ondemand governor, and let the user
configure the iowait time as busy or idle through the io_is_busy sysfs
interface.

By default, io_is_busy is disabled.

[toddpoynor@google.com: minor updates]
Change-Id: If7d70ff864c43bc9c8d7fd7cfc66f930d339f9b4
Signed-off-by: Lianwei Wang <lian-wei.wang@motorola.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:22 -07:00
Minsung Kim
a9dbf84177 cpufreq: interactive: allow arbitrary speed / delay mappings
Accept a string of delays and speeds at which to apply the delay before
raising each step above hispeed. For example, "80000 1300000:200000
1500000:40000" means that the delay at or above 1GHz, until 1.3GHz is 80 msecs,
the delay until 1.5GHz is 200 msecs and the delay at or above 1.5GHz is 40
msecs when hispeed_freq is 1GHz.

[toddpoynor@google.com: add documentation]
Change-Id: Ifeebede8b1acbdd0a53e5c6916bccbf764dc854f
Signed-off-by: Minsung Kim <ms925.kim@samsung.com>
2013-07-01 14:16:22 -07:00
Lianwei Wang
de096a7b3f cpufreq: interactive: fix race on governor start/stop
There is race condition when both two cpu do CPUFREQ_GOV_STOP and one cpu
do CPUFREQ_GOV_START soon. The sysfs_remove_group is not done yet on one
cpu, but sysfs_create_group is called on another cpu, which cause governor
start failed and then kernel panic in timer callback because the policy and
cpu mask are all kfree in cpufreq driver.

Replace atomic with mutex to lock the whole START/STOP sequence.

Change-Id: I3762b3d44315ae021b8275aca84f5ea9147cc540
Signed-off-by: Lianwei Wang <a22439@motorola.com>
2013-07-01 14:16:19 -07:00
Todd Poynor
0f44c51f17 cpufreq: interactive: fix deadlock on spinlock in timer
Need to use irqsave/restore spinlock calls to avoid a deadlock in calls
from the timer.

Change-Id: I15b6b590045ba1447e34ca7b5ff342723e53a605
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:19 -07:00
Todd Poynor
bfea469069 cpufreq: interactive: don't handle transition notification if not enabled
If multiple governors are in use then avoid processing frequency transition
notifications for CPUs on which the interactive governor is not enabled.

Change-Id: Ibd75255b921d887501a64774a8c4f62302f2d4e4
Reported-by: Francisco Franco <francisco.franco@cloudcar.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:19 -07:00
Todd Poynor
5f94a8a7b6 cpufreq: interactive: init default values at compile time
Change-Id: Ia4966e949a6c24c34fdbd4a6e522cd7c37e4108e
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:18 -07:00
Todd Poynor
cefa3db706 cpufreq: interactive: default go_hispeed_load 99%, doc updates
Update default go_hispeed_load from 85% to 99%.  Recent changes to the
governor now use a default target_load of 90%.  go_hispeed_load should
not be lower than the target load for hispeed_freq, which could lead
to oscillating speed decisions.  Other recent changes reduce the need
to dampen speed jumps on load spikes, while input event boosts from
userspace are the preferred method for anticipating load spikes with
UI impacts.

General update to the documentation to reflect recent changes.

Change-Id: I1b92f3091f42c04b10503cd1169a943b5dfd6faf
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:18 -07:00
Todd Poynor
1d0427d1c3 cpufreq: interactive: fix race on timer restart on governor start
Starting the governor, or restarting on a hotplugged-in CPU, can race
with the timer start in idle, triggering a BUG on timer already pending.
Start the timer before setting the enable flag, and use enable_sem to
protect the sequence (and ensure correct order of the update to the
enable flag).  Delete any existing timer for safety.

Change-Id: Ife77cf9fe099e8fd8543224cbf148c6722c2ffb0
Reported-by: Francisco Franco <francisco.franco@cloudcar.com>
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:18 -07:00
Todd Poynor
beb55c19d5 cpufreq: interactive: fix racy timer stopping
When stopping the governor, del_timer_sync() can race against an
invocation of the idle notifier callback, which has the potential
to reactivate the timer.

To fix this issue, a read-write semaphore is used. Multiple readers are
allowed as long as pcpu->governor_enabled is true.  However it can be
moved to false only after taking a write semaphore which would wait for
any on-going asynchronous activities to complete and prevent any more of
those activities to be initiated.

[toddpoynor@google.com: cosmetic and commit text changes]
Change-Id: Ib51165a735d73dcf964a06754c48bdc1913e13d0
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
2013-07-01 14:16:18 -07:00
Todd Poynor
f5e5ad4292 cpufreq: interactive: fix boosting logic
35a84de cpufreq: interactive: apply above_hispeed_delay to each step above hispeed

caused the speed choice logic to osciallate between boosting and not boosting.
Add back code to ensure speed does not drop below boost frequency while
boosting.

Change-Id: Id420068480fcc7f5c4989ff523e2a8d22e2f4db2
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:18 -07:00
Todd Poynor
07af93ad6e cpufreq: interactive: add timer slack to limit idle at speed > min
Always use deferrable timer for load sampling.

Set a non-deferrable timer to an additional slack time to allow prior to
waking up from idle to drop speed when not at minimum speed.  Slack value
-1 avoids wakeups to drop speed.  Default is 80ms.

Remove the governidle module param and its timer management in idle.  For
platforms on which holding speed above mimum in idle costs power, use the
new timer slack to select how long to wait before waking up to drop speed.

Change-Id: I270b3980667e2c70a68e5bff534124b4411dbad5
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:18 -07:00
Todd Poynor
8c4fc9a26e cpufreq: interactive: specify duration of CPU speed boost pulse
Sysfs attribute boostpulse_duration specifies the duration of boosting CPU
speed in response to bootpulse events.  Duration is specified in usecs,
default 80ms.

Change-Id: Ifd41625574891a44f1787a4e85d1e7b4f2afb52b
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:17 -07:00
Todd Poynor
5b28b65949 cpufreq: interactive: adjust load for changes in speed
Add notifier for speed transitions.  Keep a count of CPU active
microseconds times current frequency, converted to a percentage relative
to the current frequency when load is evaluated.

Change-Id: I5c27adb11081c50490219784ca57cc46e97fc28c
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:17 -07:00
Todd Poynor
404bca0758 cpufreq: interactive: remove load since last speed change
The longer-term load since last speed change isn't terribly useful,
may delay recognition of dropping load, and would need forthcoming
changes to adjust load for changing CPU speeds.  Drop it.

Change-Id: Ic3cbb0542cc3484617031787e03ed9bdd632dec1
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:15 -07:00
Todd Poynor
04b3fd6f5f cpufreq: interactive: allow arbitrary speed / target load mappings
Accept a string of target loads and speeds at which to apply the
target loads, per the documentation update in this patch.  For example,
"85 1000000:90 1700000:99" targets CPU load 85% below speed 1GHz,  90%
at or above 1GHz, until 1.7GHz and above, at which load 99% is targeted.

Attempt to avoid oscillations by evaluating the current speed
weighted by current load against each new choice of speed, choosing a
higher speed if the current load requires a higher speed.

Change-Id: Ie3300206047c84eca5a26b0b63ea512e5207550e
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:15 -07:00
Todd Poynor
b1a39c5c2a cpufreq: interactive: apply above_hispeed_delay to each step above hispeed
Apply above_hispeed_delay whenever increasing speed to a new speed above
hispeed (not just the first step above hispeed).

Change-Id: Ibb7add7db47f2a4306a9458c4e1ebabb60698636
Signed-off-by: Todd Poynor <toddpoynor@google.com>
2013-07-01 14:16:14 -07:00