cpufreq: interactive: Revert Samsung's contributions

The changes seem to be able to adapt to load quite well, but
doesn't justify deviating so much from upstream.

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
cpufreq: interactive: Fix null pointer dereference in interactive governor

For the sync_freq feature currently we check pcpu->policy->cur frequency
for each online cpu.  But for a CPU that isn't using interactive governor
or for an offline CPU, pcpu->policy can be null or an invalid value.
This patch tries to avoid that scenario by using pcpu->target_freq
instead of policy->cur to get the frequency of an online CPU.

Kernel crash without this patch:
[   20.132373] Unable to handle kernel NULL pointer dereference at virtual address 00000028
[   20.132375] pgd = c34f34c0
[   20.132377] pgd = ef6f2440
[   20.132383] [00000028] *pgd=00000000
[   20.132385]
[   20.132388] [00000028] *pgd=2e98f003, *pmd=00000000
[   20.132390] Internal error: Oops: 205 [#1] PREEMPT SMP ARM
[   20.132394] Modules linked in:
[   20.132398] CPU: 0 PID: 1560 Comm: chown Tainted: G        W    3.10.0-perf-gb12057b-00001-ga2c6c16-dirty #7
[   20.132401] task: ef9af300 ti: ee49c000 task.ti: ee49c000
[   20.132411] PC is at cpufreq_interactive_timer+0x10c/0x650
[   20.132415] LR is at cpufreq_interactive_timer+0x128/0x650
<snip>
[   20.133002] [<c07eb204>] (cpufreq_interactive_timer+0x10c/0x650) from [<c02804d8>] (call_timer_fn+0x80/0x198)
[   20.133012] [<c02804d8>] (call_timer_fn+0x80/0x198) from [<c0280acc>] (run_timer_softirq+0x1f8/0x270)
[   20.133019] [<c0280acc>] (run_timer_softirq+0x1f8/0x270) from [<c0279e20>] (__do_softirq+0x12c/0x2d4)
[   20.133025] [<c0279e20>] (__do_softirq+0x12c/0x2d4) from [<c027a2d4>] (irq_exit+0x74/0xc8)
[   20.133034] [<c027a2d4>] (irq_exit+0x74/0xc8) from [<c0206a00>] (handle_IRQ+0x68/0x8c)
[   20.133041] [<c0206a00>] (handle_IRQ+0x68/0x8c) from [<c02004b8>] (gic_handle_irq+0x3c/0x60)
[   20.133051] [<c02004b8>] (gic_handle_irq+0x3c/0x60) from [<c0ac6900>] (__irq_svc+0x40/0x70)
<snip>

Change-Id: Ie834f5d383de4d41e0fe6fbd40c8b0a0c05d82f5
Signed-off-by: Vijay Ganti <viganti@codeaurora.org>
cpufreq: interactive: delete timers for GOV_START

Make sure that timers cpu_timer and cpu_slack_timer
deactivated before addition of new.

Change-Id: If31c4049606871df6f00efdc24b1d713c86a6f69
Signed-off-by: Shridhar Rasal <srasal@nvidia.com>
Signed-off-by: Bharat Nihalani <bnihalani@nvidia.com>
Git-commit: b430123367e78a6557bac3cf1558bcb85193fb12
Git-repo: https://android.googlesource.com/kernel/common/
[mattw@codeaurora.org: resolved trivial context conflict]
Signed-off-by: Matt Wagantall <mattw@codeaurora.org>
cpufreq: Sync on thread migration optimizations

When threads migrate between CPUs the destination CPU will temporarily
have a boosted frequency and the source CPU will have a residual higher
frequency even though the load could have just been reduced. To avoid
leaving CPUs at a high frequencies notify the source CPU after a thread
migration and make the interactive governor's timer reschedule
conditionally.

Change-Id: Id55055f2a116ca7ffd2a34dc3d0ec519c888a111
Signed-off-by: Patrick Cain <pcain@codeaurora.org>
cpufreq: interactive: Don't reset sampling down factor at max freq

A previous patch sets the min_sample_time to zero if the cpufreq
min/max limits have changed which would bring down the frequency
in the next sample even if min_sample_time doesnt allow it to do so.
This could severly affect benchmarks if this is applied to max
frequencies as min_sample_time for max frequencies is set to
sampling_down_factor.
This patch resets the limits_changed flag for cases where timer fires
while running at max frequencies so that sampling_down_factor is
still applicable as before.

Change-Id: I397133cb15eea4ab999d0f69617b4922438c6e11
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
cpufreq: interactive: Remove unnecessary cpu_online() check

Cpufreq no longer calls governor callback for offlined cpus. i.e. All
policy->cpus are guaranteed to be online. Hence we don't need explicit check to
see if cpu is online or not.

Change-Id: I9ad85ea4addd5b4a40952e59ed730dd15e328690
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
cpufreq: interactive: Move definition of cpufreq_gov_interactive downwards

This moves definition of cpufreq_gov_interactive towards the bottom of file, so
that we don't have to add prototype of cpufreq_governor_interactive() in the
beginning of file.

Change-Id: I04bd1004954eb36502c5cd7e35d3d7274cddaf95
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Git-commit: e50d640cacfe61e69f1b4fa92fa0174c688e919c
Git-Repo: https://android.googlesource.com/kernel/common.git
[junjiew@codeaurora.org: Resolve merge conflicts]
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: Move get_cpu_idle_time() to cpufreq.c

Governors other than ondemand and conservative can also use
get_cpu_idle_time() and they aren't required to compile
cpufreq_governor.c. So, move these independent routines to
cpufreq.c instead.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Git-commit: 72a4ce340a7ebf39e1c6fdc8f5feb4f974d6c635
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
[junjiew@codeaurora.org: update non-upstream files]
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

Change-Id: I3227454599250011a19a752c962e3cacb1fb0301
cpufreq: interactive: Squashed cleanup patches

Revert "cpufreq: interactive: Remove unnecessary cpu_online() check"

This reverts commit 7b46e2e6d8a3c3c32706ee3c3c3b507d050bedfb.

Revert "cpufreq: interactive: Allow 1 ms error in above_hispeed_delay comparisons"

This reverts commit ff6af80775231f1dfab8353d0b665718222218bf.

Commit ff6af807 tries to avoid a corner case where frequency is stuck in
hispeed_freq for one additional window. For example, if timer_rate is
20ms, and go_hispeed_delay is 40ms, frequency might be stuck at
hispeed_freq for 60ms due to imprecision in jiffies. Same problem can be
easily solved by making go_hispeed_delay 1ms smaller instead of changing
the code.

Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

cpufreq: interactive: Revert timer start modification

commit f8b276565ce95bd788af0fc8d060f92632590a40
(cpufreq: Sync on thread migration optimizations)
introduced a change to cpufreq_interactive_timer_start() in order
to reschedule the timer differently based on whether min or max
is changed. A better way is to reschedule the timer only when
necessary.

Revert timer start modification in preparation for the final fix.

Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

Revert "cpufreq: interactive: Optimize sync_freq implementation"

This reverts commit 4da7f27d4dbd5bcfb8479467444f2cf198217933.

cpufreq: interactive: Revert sync on thread migration optimizations

Commit f8b276565ce95bd788af0fc8d060f92632590a40
(cpufreq: Sync on thread migration optimizations) is no longer needed
for targets with synchronous CPUs.

Part of that commit has already been reverted in
a913b3afcaa55356f5f793ae895312c8ae7e1f71
(cpufreq: interactive: Revert timer start modification)

This commit reverts the remaining changes.

Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

cpufreq: interactive: Revert sync freq feature

Sync freq feature is not valid for a HMP system with clusters.

This commit reverts commit f3d1980b4db4c20f21acaed59cc511c2df84cec2
(cpufreq: interactive: sync freq feature for interactive governor)

Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

cpufreq: interactive: Remove sampling_down_factor

Remove sampling_down_factor feature.

This commit revert d094d23694edf41fee50ebc544795d6116451643
(cpufreq: interactive: Add a sampling_down_factor for max frequencies)
and subsequent modifications related to sampling down factor.

Signed-off-by: Junjie Wu <junjiew@codeaurora.org>

Conflicts:
	drivers/cpufreq/cpufreq_interactive.c

Change-Id: I9e5fd451e7eaefe8ef7775365cc5a4527d37188f
cpufreq: interactive: Align timer windows for all CPUs

It's more advantageous to evaluate all CPUs at same time so that
interactive governor gets a complete picture of the load on
each CPU at a specific time. It could also reduce number of speed
changes made if there are many CPUs controlled by same policy. In
addition, waking up all CPUs at same time would allow the cluster
to go into a deeper sleep state when it's idle.

Change-Id: I6915050c5339ef1af106eb906ebe4b7c618061e2
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Reset last evaluated jiffy in idle callback

When CPU has been busy for a long time, last evaluated jiffy will be
quite behind because the timer would have been canceled. We don't want
to schedule a timer to fire in the past as load will always be 100%.

Reset last evaluated jiffy so that timer will be scheduled for the
next window.

Change-Id: Ie25e65eab1f16acdeda267987ca605d653f1f32a
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Round up timer_rate to match jiffy

Timers are scheduled in unit of jiffies. Round up timer_rate so that
it matches the actual sampling period.

Change-Id: I47e666f835752528331f50b1e76784e6d67f8bcf
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Use del_timer/add_timer_on to rearm timers

Replace mod_timer_pinned() with del_timer(), add_timer_on().
mod_timer_pinned() always adds timer onto current CPU. Interactive
governor expects each CPU's timers to be running on the same CPU.
If cpufreq_interactive_timer_resched() is called from another CPU,
the timer will be armed on the wrong CPU.

Replacing mod_timer_pinned() with del_timer() and add_timer_on()
guarantees timers are still run on the right CPU even if another
CPU reschedules the timer. This would provide more flexibility
for future changes.

Change-Id: I3a10be37632afc0ea4e0cc9c86323b9783b216b1
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Add max_freq_hysteresis feature

Previously known as sampling down factor, max_freq_hysteresis
extends the period that interactive governor will stay at policy->max.
This feature is to accomodate short idle periods in an otherwise very
intensive workload.

When the feature is enabled, it ensures that once a CPU goes to max
frequency, it doesn't reduce the frequency for max_freq_hysteresis
microseconds from the time it first goes to idle.

Change-Id: Ia54985cb554f63f8c22d0b554a0a0f2ed2be038f
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Make window alignment optional

Make sampling window alignment optional when scheduler inputs
are not enabled.

Change-Id: If69c111a3efe219cdd1e38c1f46f03404789c0bb
Signed-off-by: Junjie Wu <junjiew@codeaurora.org>
cpufreq: interactive: Exercise hispeed settings at a policy level

If a heavy task migrates between otherwise idle CPUs in a policy during
every sample window, the above hispeed delay window for the CPUs would get
restarted for every sample window. Due to the continuous restart of above
hispeed delay window, none of the CPUs would ever pick a target frequency
higher than hispeed frequency. This causes the policy's frequency to be
stuck at hispeed freq even if the load justifies a higher frequency.

To fix this, the above high speed delay window is restarted only when the
policy frequency changes. This ensures that tasks migrating between CPUs in
a policy are handled correctly.

Also, the hispeed load/frequency heuristic is only necessary when the
information is insufficient to determine if the load on the CPU needs at
least hispeed frequency. When the policy frequency is already at or above
hispeed frequency, if the CPU load% based on policy frequency is not above
hispeed load, then the information is clearly sufficient to determine that
the load on the CPU does not need hispeed frequency.

Therefore, compute CPU load% (which is used only to compare against hispeed
load) based on policy frequency instead of CPU target frequency.

Change-Id: I1749d663949e34753ecb5c426a16563796f8b0b2
Signed-off-by: Saravana Kannan <skannan@codeaurora.org>