[PATCH v5] Provide USF for the portable equipment.

[Dongdong Yang]

From: Dongdong Yang <yangdongdong@xxxxxxxxxx>

This patch provides USF(User Sensitive Feedback factor) auxiliary
cpufreq governor to support high level layer sysfs inodes setting for
util adjustment purpose from the identified scenario on portable
equipment. Because the power consumption and UI response are more cared
for by portable equipment users. And the "screen off" status stands for
no request from the user, however, the kernel is still expected to
notify the user in time on modem, network or powerkey events occur. USF
provides "non_ux_r" sysfs inode to cut down the utils from user space
tasks according to high level scenario. In addition, it usually hints
more cpufreq demand that the preemptive counts of the tasks on the cpu
burst and over the user expecting completed time such as the ratio
sysctl_sched_latency to sysctl_sched_min_granularity on "screen on"
status, which more likely with more UI. The sysfs inodes "up_l0_r" and
"down_r" have been provided to adjust the utils according to high level
identified scenario to alloc the cpufreq in time.

Changes in v5
Based on comments from Greg, Peterz, Qais and Randy
  - Updated USF sysfs to ABI
  - Updated the names of USF functions.
  - Clean sched.h and trace.h changes.

Changes in v4
Based on comments from Greg, Randy and Viresh
  - Add USF sysfs to ABI
  - Remove kobj field from usf.
  - Clean Kconfig left at staging.

Changes in v3
Based on comments from Greg, Dietmar, Christoph and Randy
  - Move usf.c to kernel/sched from staging.
  - Remove trace_printk and debugfs.
  - Add document draft.
  - Update comments.

Changes in v2
Based on comments from Steven, Greg, Peter and Dan:
  - Add adjust_task_pred_set switch.
  - Move adjust_task_pred_demand declaration into sched.h
  - Update comments.
  - Clean usf structure.

Changes in v1
Initial USF 

Dongdong Yang (1):
  sched: Provide USF for the portable equipment.

 Documentation/ABI/testing/sysfs-devices-system-cpu |  31 ++
 drivers/cpufreq/Kconfig                            |  11 +
 kernel/sched/Makefile                              |   1 +
 kernel/sched/cpufreq_schedutil.c                   |   5 +
 kernel/sched/usf.c                                 | 314 +++++++++++++++++++++
 5 files changed, 362 insertions(+)
 create mode 100644 kernel/sched/usf.c

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2.7.4