sched: shortcut to remove load_idx

Shortcut to remove rq->cpu_load[load_idx] effect in scheduler.
In five load idx, only busy_idx, idle_idx are not zero.
Newidle_idx, wake_idx and fork_idx are all zero in all archs.

So, change the idx to zero here can fully remove load_idx effect.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: remove rq->cpu_load[load_idx] array

Since load_idx effect removed in load balance, we don't need the
load_idx decays in scheduler. that will save some process in sched_tick
and others places.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: clean up cpu_load update

Since we don't decay the rq->cpu_load, so we don't need the
pending_updates. But we still want update rq->rt_avg, so
still keep rq->last_load_update_tick and func __update_cpu_load.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: unify imbalance bias for target group

Old code considers the bias in source/target_load already. but still
use imbalance_pct as last check in idlest/busiest group finding. It is
also a kind of redundant job. If we bias imbalance in source/target_load,
we'd better not use imbalance_pct again.

After cpu_load array removed, it is nice time to unify the target bias
consideration. So I remove the imbalance_pct from last check and add the
live bias using.

On wake_affine, since all archs' wake_idx is 0, current logical is just
want to prefer current cpu. so we follows this logical. Just renaming the
target_load/source_load to wegithed_cpuload for more exact meaning.
Thanks for reminding from Morten!

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: rewrite update_cpu_load_nohz

After change to sched_avg, the cpu load in idle exit was decayed.
So, it maybe near zero if waking a long time sleep task, or, a full
non-decay load if waking a new forked task. Then, we can use it to
reflect the cpu load, don't need to pretend 0.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: clean up source_load/target_load

Don't need 'rq' variable now.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: replace source_load by weighted_cpuload

Now, without load_idx source_load is just weighted_cpuload, so
replace it to reduce a conception for cpu load.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: remove rq->cpu_load and rq->nr_load_updates

The cpu_load is the copy of rq->cfs.runnable_load_avg. And it updated
on time. So we can use the latter directly. Thus saved 2 rq variables:
cpu_load and nr_load_updates.
Then don't need __update_cpu_load(), just keep sched_avg_update().
Thus removed get_rq_runnable_load() which used for update_cpu_load only.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: rename update_*_cpu_load

Since we have no cpu_load update, rename the related functions:
s/update_idle_cpu_load/update_idle_rt_avg/
s/update_cpu_load_nohz/update_rt_avg_nohz/
s/update_cpu_load_active/update_avg_load_active/

No functional change.

Signed-off-by: Alex Shi <alex.shi@linaro.org>
sched: clean up task_hot function

task_hot doesn't need the 'sched_domain' parameter, so remove it.

Signed-off-by: Alex Shi <alex.shi@linaro.org>