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>
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>
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>
alarmtimer: Use hrtimer per-alarm instead of per-base

Arve Hjønnevåg reported numerous crashes from the
"BUG_ON(timer->state != HRTIMER_STATE_CALLBACK)" check
in __run_hrtimer after it called alarmtimer_fired.

It ends up the alarmtimer code was not properly handling
possible failures of hrtimer_try_to_cancel, and because
these faulres occur when the underlying base hrtimer is
being run, this limits the ability to properly handle
modifications to any alarmtimers on that base.

Because much of the logic duplicates the hrtimer logic,
it seems that we might as well have a per-alarmtimer
hrtimer, and avoid the extra complextity of trying to
multiplex many alarmtimers off of one hrtimer.

Thus this patch moves the hrtimer to the alarm structure
and simplifies the management logic.

Change-Id: I54b2d718ed1d39598e321eacf88c3335284d4cea
Cc: Arve Hjønnevåg <arve@android.com>
Cc: Colin Cross <ccross@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-by: Arve Hjønnevåg <arve@android.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
alarmtimer: add alarm_restart

Analogous to hrtimer_restart, restart an alarmtimer after the expires
time has already been updated (as with alarm_forward).

Change-Id: Ia2613bbb467404cb2c35c11efa772bc56294963a
Signed-off-by: Todd Poynor <toddpoynor@google.com>
alarmtimer: add alarm_forward_now

Similar to hrtimer_forward_now, move the expires time forward to an
interval from the current time of the associated clock.

Change-Id: I73fed223321167507b6eddcb7a57d235ffcfc1be
Signed-off-by: Todd Poynor <toddpoynor@google.com>
alarmtimer: add alarm_start_relative

Start an alarmtimer with an expires time relative to the current time
of the associated clock.

Change-Id: Ifb5309a15e0d502bb4d0209ca5510a56ee7fa88c
Signed-off-by: Todd Poynor <toddpoynor@google.com>
alarmtimer: add alarm_expires_remaining

Similar to hrtimer_expires_remaining, return the amount of time
remaining until alarm expiry.

Change-Id: I8c57512d619ac66bcdaf2d9ccdf0d7f74af2ff66
Signed-off-by: Todd Poynor <toddpoynor@google.com>
timerfd: add alarm timers

Add support for clocks CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM.

Change-Id: Iafc8445d3d7ffb35110c860f1607bf03f1edb895
Signed-off-by: Todd Poynor <toddpoynor@google.com>