sched: Call the notify_on_migrate notifier chain for wakeups as well

Add a change to send notify_on_migrate hints on wakeups of
foreground tasks from scheduler if their load is above
wakeup_load_thresholds (default value is 60).
These hints can be used to choose an appropriate CPU frequency
corresponding to the load of the task being woken up.

Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Conflicts:
	kernel/sched/core.c
sched: Window-based load stat improvements

Some tasks can have a sporadic load pattern such that they can suddenly
start running for longer intervals of time after running for shorter
durations. To recognize such sharp increase in tasks' demands, max
between the average of 5 window load samples and the most recent sample
is chosen as the task demand.

Make the window size (sched_ravg_window) configurable at boot up
time. To prevent users from setting inappropriate values for window
size, min and max limits are defined. As 'ravg' struct tracks load for
both real-time and non real-time tasks it is moved out of sched_entity
struct.

In order to prevent changing function signatures for move_tasks() and
move_one_task() per-cpu variables are defined to track the total load
moved. In case multiple tasks are selected to migrate in one load
balance operation, loads > 100 could be sent through migration notifiers.
Prevent this scenario by setting mnd.load to 100 in such cases.

Define wrapper functions to compute cpu demands for tasks and to change
rq->cumulative_runnable_avg.

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Signed-off-by: Rohit Gupta <rohgup@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>

Conflicts:
	kernel/sched/core.c
	kernel/sched/fair.c
sched: Calculate max_possible_freq based on current policy->max

Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>
sched: window-stats: Fix overflow bug

Multiplication over-flow possibility exists in update_task_ravg() when
updating task's window_start. That would lead to incorrect accounting
of task load. Fix the issue by using 64-bit arithmetic.

Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Signed-off-by: Pranav Vashi <neobuddy89@gmail.com>