Message-Id: <23719695ee476715ec54d3310c95d535f8e1391a.1596464896.git.yangdongdong@xiaomi.com>
Date:   Mon,  3 Aug 2020 22:31:15 +0800
From:   Dongdong Yang <contribute.kernel@...il.com>
To:     gregkh@...uxfoundation.org, rjw@...ysocki.net,
        viresh.kumar@...aro.org, mingo@...hat.com, peterz@...radead.org,
        juri.lelli@...hat.com, vincent.guittot@...aro.org,
        dietmar.eggemann@....com, rostedt@...dmis.org, bsegall@...gle.com,
        mgorman@...e.de
Cc:     linux-kernel@...r.kernel.org, devel@...verdev.osuosl.org,
        linux-pm@...r.kernel.org, yangdongdong@...omi.com,
        tanggeliang@...omi.com, taojun@...omi.com, huangqiwu@...omi.com,
        rocking@...ux.alibaba.com, fengwei@...omi.com,
        zhangguoquan@...omi.com, gulinghua@...omi.com, duhui@...omi.com
Subject: [PATCH v3] sched: Provide USF for the portable equipment.

From: Dongdong Yang <yangdongdong@...omi.com>

The power consumption and UI response are more cared for by the portable
equipment users. USF(User Sensitive Feedback factor) auxiliary cpufreq
governor is providing more utils adjustment settings to the high level
by scenario identification.

>From the view of portable equipment, screen off status usually 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. In
some scenarios, such as listening to music, low power processors, such
as DSP, take more actions and CPU load requirements cut down.  It would
bring more power consumption benefit if high level have interfaces to
adjust utils according to the current scenario and load.

In addition, the portable equipment user usually heavily interact with
devices by touch, and other peripherals. The boost preemptive counts
are marking the load requirement urgent, vice versa. If such feedback
factor could be set to high level according to the scenario, it would
contribute to the power consumption and UI response.

If no USF sysfs inode is set, and no screen on or off event,
adjust_task_pred_demand shall not be invoked. Once sched_usf_up_l0_r
sched_usf_down_r or sched_usf_non_ux_r be set, adjust_task_pred_demand
shall be called back to update settings according to high level
scenario identification.

We can get about 17% mean power consumption save at listening to music
with speaker on "screen off" scenario, as below statistical data from
7766 XiaoMi devices for two weeks with sched_usf_non_ux_r be set:

        day1         day2         day3         day4
count   7766.000000  7766.000000  7766.000000  7766.000000
mean    88.035525    85.500282    83.829305    86.054997
std     111.049980   108.258834   107.562583   108.558240
min     0.099000     0.037000     0.067000     0.045000
25%     34.765500    34.021750    34.101500    34.423000
50%     54.950000    55.286500    54.189500    54.248500
75%     95.954000    93.942000    91.738000    94.0592500
80%     114.675000   107.430000   106.378000   108.673000
85%     137.851000   129.511000   127.156500   131.750750
90%     179.669000   170.208500   164.027000   172.348000
95%     272.395000   257.845500   247.750500   263.275750
98%     399.034500   412.170400   391.484000   402.835600

        day5         day6        day7         day8
count   7766.000000  7766.00000  7766.000000  7766.000000
mean    82.532677    79.21923    77.611380    81.075081
std     104.870079   101.34819   103.140037   97.506221
min     0.051000     0.02900     0.007000     0.068000
25%     32.873000    33.44400    31.965500    33.863500
50%     52.180500    51.56550    50.806500    53.080000
75%     90.905750    86.82625    83.859250    89.973000
80%     105.455000   99.64700    97.271000    104.225000
85%     128.300000   118.47825   116.570250   126.648250
90%     166.647500   149.18000   150.649500   161.087000
95%     247.208500   224.36050   226.380000   245.291250
98%     393.002000   347.92060   369.791800   378.778600

        day9         day10        day11        day12
count   7766.000000  7766.000000  7766.000000  7766.000000
mean    79.989170    83.859417    78.032930    77.060542
std     104.226122   108.893043   102.561715   99.844276
min     0.118000     0.017000     0.028000     0.039000
25%     32.056250    33.454500    31.176250    30.897750
50%     51.506000    54.056000    48.969500    49.069000
75%     88.513500    92.953500    83.506750    84.096000
80%     102.876000   107.845000   97.717000    98.073000
85%     124.363000   128.288000   118.366500   116.869250
90%     160.557000   167.084000   154.342500   148.187500
95%     231.149000   242.925750   236.759000   228.131250
98%     367.206600   388.619100   385.269100   376.541600

        day13        day14
count   7766.000000  7766.000000
mean    75.528036    73.702878
std     90.750594    86.796016
min     0.066000     0.054000
25%     31.170500    31.608500
50%     48.758500    49.215000
75%     84.522750    83.053000
80%     97.879000    94.875000
85%     116.680250   113.573750
90%     149.083500   144.089500
95%     226.177750   211.488750
98%     347.011100   331.317100

Signed-off-by: Dongdong Yang <yangdongdong@...omi.com>
Co-developed-by: Jun Tao <taojun@...omi.com>
Co-developed-by: Qiwu Huang <huangqiwu@...omi.com>
Co-developed-by: Peng Wang <rocking@...ux.alibaba.com>
---
 Documentation/scheduler/sched-ufs.txt |  78 +++++++++
 drivers/cpufreq/Kconfig               |  11 ++
 drivers/staging/Kconfig               |   2 +
 drivers/staging/Makefile              |   1 +
 include/trace/events/sched.h          |  35 ++++
 kernel/sched/Makefile                 |   1 +
 kernel/sched/cpufreq_schedutil.c      |   3 +
 kernel/sched/sched.h                  |  10 ++
 kernel/sched/usf.c                    | 305 ++++++++++++++++++++++++++++++++++
 9 files changed, 446 insertions(+)
 create mode 100644 Documentation/scheduler/sched-ufs.txt
 create mode 100644 kernel/sched/usf.c

diff --git a/Documentation/scheduler/sched-ufs.txt b/Documentation/scheduler/sched-ufs.txt
new file mode 100644
index 0000000..95fbb52
--- /dev/null
+++ b/Documentation/scheduler/sched-ufs.txt
@@ -0,0 +1,78 @@
+           User Sensitive Feedback factor auxiliary scheduling
+                           (EXPERIMENTAL)
+
+
+Table of Contents
+=================
+
+1. Motivation
+2. Introduction
+3. System wide settings
+
+
+1. Motivation
+=============
+
+The power consumption and UI response are more cared for by the portable
+equipment users. USF(User Sensitive Feedback factor) auxiliary cpufreq governor
+is providing more utils adjustment settings to the high level by scenario
+identification.
+
+
+2. Introduction
+===============
+
+The USF auxiliary scheduling is based on FrameBuffer and schdeutil cpufreq
+governor to adjust utils by the identificated scenario from User Space.
+It is for portable equipment which "screen off" status stands for no request
+from user, however, the kernel is still expected to notify the user for UI in
+time on modem, network or powerkey events occur. In order to save power, the
+sysfs inode nonux is provided to set the utils down level on userspace tasks.
+
+In addition, the portable equipment users usually heavily interact with devices
+by touch, and other peripherals. On "screen on" status, The boost preemptive
+counts are marking the load requirement urgent, vice versa. USF provides up and
+down sysfs inodes to adjust utils according to such feedback factor and the
+level setting from the user space identified secnario. 
+
+adjust_task_pred_set is as the switch to enable or disable the adjustment.
+If no USF sysfs inodes is set and no screen on or off event be received,
+adjust_task_pred_demand shall not be executed. 
+ 
+
+3. System wide settings
+=======================
+
+sched_usf_non_ux_r:
+	The ratio of utils is cut down on screen off. The default value is 0,
+	which no util be adjusted on sugov calculating utils to select cpufreq.
+	Its range is [-100 , 0]. If its value falls into [-50, 0), the half of
+	utils, which calculates cpufreq, shall be  cut down. If its value falls
+	into [-100, -50), only a quarter of utils be left to contintue to
+	calculates cpufreq.
+	It is expected to be set [-100, 0) once enter into the identificated
+	scenario, such as listen to music on screen off, and recover to 0 on
+	out of the scenario, such as screen on.
+
+sched_usf_up_l0_r:
+	The ratio of utils is boost up on screen on. The default value is 0,
+	which no util be adjusted on sugov calculates utils to select cpufreq.
+	Its range is [0 , 100]. If its value falls into (0, 50], a quarter of
+	extra utils, which calculates cpufreq, shall be added. If its value
+	falls into (50, 100], the half of extra utils be added to contintue to
+	calculates cpufreq.
+	It is expected to be set (0, 100] once enter into the identificated
+	scenario, such as browsing videolet on screen on, and recover to 0 on
+	out of the scenario, such as screen off or videolet into background.
+
+sched_usf_down_r:
+	The ratio of utils is cut down on screen on. The default value is 0,
+	which no util be adjusted on sugov calculating utils to select cpufreq.
+	Its range is [-100 , 0]. If its value falls into [-50, 0), the half of
+	utils, which calculates cpufreq, shall be  cut down. If its value falls
+	into [-100, -50), only a quarter of utils be left to contintue to
+	calculates cpufreq.
+	It is expected to be set [-100, 0) once enter into the identificated
+	scenario, such as browsing videolet on screen on, and recover to 0 on
+	out of the scenario, such as screen off or vidolet into background.
+
diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
index e917501..a21c6ad 100644
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -224,6 +224,17 @@ config CPUFREQ_DT_PLATDEV
 
 	  If in doubt, say N.
 
+config SCHED_USF
+	bool "User Sensitive Factors for Scheduler"
+	depends on CPU_FREQ_GOV_SCHEDUTIL && FB
+	help
+	  Select this option to enable the adjustment on the cpufreq with
+	  the user sensitive factors on schedule. It is special for mobile
+	  devices which more power care and quick response requirement on
+	  screen on.
+
+	  If unsure, say N.
+
 if X86
 source "drivers/cpufreq/Kconfig.x86"
 endif
diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index 4ec5528..05b231e 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -120,4 +120,6 @@ source "drivers/staging/qlge/Kconfig"
 
 source "drivers/staging/wfx/Kconfig"
 
+source "drivers/staging/fbsched/Kconfig"
+
 endif # STAGING
diff --git a/drivers/staging/Makefile b/drivers/staging/Makefile
index 4d34198..e016ec6 100644
--- a/drivers/staging/Makefile
+++ b/drivers/staging/Makefile
@@ -50,3 +50,4 @@ obj-$(CONFIG_FIELDBUS_DEV)     += fieldbus/
 obj-$(CONFIG_KPC2000)		+= kpc2000/
 obj-$(CONFIG_QLGE)		+= qlge/
 obj-$(CONFIG_WFX)		+= wfx/
+obj-$(CONFIG_SCHED_USF)		+= fbsched/
diff --git a/include/trace/events/sched.h b/include/trace/events/sched.h
index ed168b0..d5e20b7 100644
--- a/include/trace/events/sched.h
+++ b/include/trace/events/sched.h
@@ -488,6 +488,41 @@ TRACE_EVENT(sched_process_hang,
 #endif /* CONFIG_DETECT_HUNG_TASK */
 
 /*
+ * Tracepoint for tracking tuils be adjusted by USF:
+ */
+#ifdef CONFIG_SCHED_USF
+TRACE_EVENT(sched_usf_adjust_utils,
+
+	TP_PROTO(int cpu_id, int up, int down, int nonux, unsigned long utils),
+
+	TP_ARGS(cpu_id, up, down, nonux, utils),
+
+	TP_STRUCT__entry(
+		__field(int, cpu_id)
+		__field(int, up)
+		__field(int, down)
+		__field(int, nonux)
+		__field(unsigned long, utils)
+	),
+
+	TP_fast_assign(
+		__entry->cpu_id	= cpu_id;
+		__entry->up	= up;
+		__entry->down	= down;
+		__entry->nonux	= nonux;
+		__entry->utils	= utils;
+	),
+
+	TP_printk("cpu_id=%d up=%d down=%d nonux=%d utils=%lu",
+		  __entry->cpu_id,
+		  __entry->up,
+		  __entry->down,
+		  __entry->nonux,
+		  __entry->utils)
+);
+#endif /* CONFIG_SCHED_USF */
+
+/*
  * Tracks migration of tasks from one runqueue to another. Can be used to
  * detect if automatic NUMA balancing is bouncing between nodes.
  */
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 5fc9c9b..58a0e7b 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -36,3 +36,4 @@ obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
 obj-$(CONFIG_MEMBARRIER) += membarrier.o
 obj-$(CONFIG_CPU_ISOLATION) += isolation.o
 obj-$(CONFIG_PSI) += psi.o
+obj-$(CONFIG_SCHED_USF) += usf.o
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 7fbaee2..79a0040 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -289,12 +289,15 @@ unsigned long schedutil_cpu_util(int cpu, unsigned long util_cfs,
 	return min(max, util);
 }
 
+DEFINE_STATIC_KEY_FALSE(adjust_task_pred_set);
 static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
 {
 	struct rq *rq = cpu_rq(sg_cpu->cpu);
 	unsigned long util = cpu_util_cfs(rq);
 	unsigned long max = arch_scale_cpu_capacity(sg_cpu->cpu);
 
+	if (static_branch_unlikely(&adjust_task_pred_set))
+		adjust_task_pred_demand(sg_cpu->cpu, &util, rq);
 	sg_cpu->max = max;
 	sg_cpu->bw_dl = cpu_bw_dl(rq);
 
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 877fb08..496130b 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2540,5 +2540,15 @@ static inline bool is_per_cpu_kthread(struct task_struct *p)
 }
 #endif
 
+DECLARE_STATIC_KEY_FALSE(adjust_task_pred_set);
+#ifdef CONFIG_SCHED_USF
+void adjust_task_pred_demand(int cpuid, unsigned long *util,
+		struct rq *rq);
+#else
+static inline void adjust_task_pred_demand(int cpuid,
+		unsigned long *util, struct rq *rq)
+{ }
+#endif
+
 void swake_up_all_locked(struct swait_queue_head *q);
 void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
diff --git a/kernel/sched/usf.c b/kernel/sched/usf.c
new file mode 100644
index 0000000..0f097e7
--- /dev/null
+++ b/kernel/sched/usf.c
@@ -0,0 +1,305 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 XiaoMi Inc.
+ * Author: Yang Dongdong <yangdongdong@...omi.com>
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
+ * See http://www.gnu.org/licenses/gpl-2.0.html for more details.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/kthread.h>
+#include <linux/cpu.h>
+#include <linux/sysfs.h>
+#include <linux/kthread.h>
+#include <linux/kobject.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/kallsyms.h>
+#include <linux/fb.h>
+#include <linux/notifier.h>
+#include <trace/events/sched.h>
+#include "sched.h"
+
+#define BOOST_MIN_V -100
+#define BOOST_MAX_V 100
+#define LEVEL_TOP 3
+
+#define USF_TAG	"[usf_sched]"
+
+DEFINE_PER_CPU(unsigned long[PID_MAX_DEFAULT], task_hist_nivcsw);
+
+static struct {
+	bool is_sched_usf_enabled;
+	bool is_screen_on;
+	struct kobject *kobj;
+	int sysctl_sched_usf_up_l0;
+	int sysctl_sched_usf_down;
+	int sysctl_sched_usf_non_ux;
+	int usf_up_l0;
+	int usf_down;
+	int usf_non_ux;
+} usf_vdev;
+
+void adjust_task_pred_demand(int cpuid,
+			     unsigned long *util,
+			     struct rq *rq)
+{
+	/* sysctl_sched_latency/sysctl_sched_min_granularity */
+	u32 bl_sw_num = 3;
+
+	if (!usf_vdev.is_sched_usf_enabled || !rq || !rq->curr ||
+		(rq->curr->pid >= PID_MAX_DEFAULT))
+		return;
+
+	if (usf_vdev.is_screen_on) {
+		if (rq->curr->nivcsw >
+		    (per_cpu(task_hist_nivcsw, cpuid)[rq->curr->pid]
+		     + bl_sw_num + 1)) {
+			(*util) += (*util) >> usf_vdev.usf_up_l0;
+		} else if (rq->curr->nivcsw <
+			   (per_cpu(task_hist_nivcsw, cpuid)[rq->curr->pid]
+			    + bl_sw_num - 1) && (rq->nr_running < bl_sw_num)) {
+			(*util) >>= usf_vdev.usf_down;
+		}
+		per_cpu(task_hist_nivcsw, cpuid)[rq->curr->pid] =
+		    rq->curr->nivcsw;
+	} else if (rq->curr->mm) {
+		(*util) >>= usf_vdev.usf_non_ux;
+	}
+
+	trace_sched_usf_adjust_utils(cpuid, usf_vdev.usf_up_l0,
+				     usf_vdev.usf_down,
+				     usf_vdev.usf_non_ux, *util);
+}
+
+static int usf_lcd_notifier(struct notifier_block *nb,
+			    unsigned long val, void *data)
+{
+	struct fb_event *evdata = data;
+	unsigned int blank;
+
+	if (!evdata)
+		return 0;
+
+	if (val != FB_EVENT_BLANK)
+		return 0;
+
+	if (evdata->data && val == FB_EVENT_BLANK) {
+		blank = *(int *)(evdata->data);
+
+		switch (blank) {
+		case FB_BLANK_POWERDOWN:
+			usf_vdev.is_screen_on = false;
+			if (usf_vdev.sysctl_sched_usf_non_ux != 0)
+				static_branch_enable(&adjust_task_pred_set);
+			else
+				static_branch_disable(&adjust_task_pred_set);
+
+			break;
+
+		case FB_BLANK_UNBLANK:
+			usf_vdev.is_screen_on = true;
+			if (usf_vdev.sysctl_sched_usf_up_l0 != 0 ||
+			    usf_vdev.sysctl_sched_usf_down != 0)
+				static_branch_enable(&adjust_task_pred_set);
+			else
+				static_branch_disable(&adjust_task_pred_set);
+			break;
+		default:
+			break;
+		}
+
+		usf_vdev.is_sched_usf_enabled = true;
+		pr_info("%s : usf_vdev.is_screen_on:%b\n",
+				     __func__, usf_vdev.is_screen_on);
+	}
+	return NOTIFY_OK;
+}
+
+static struct notifier_block usf_lcd_nb = {
+	.notifier_call = usf_lcd_notifier,
+	.priority = INT_MAX,
+};
+
+static ssize_t store_sched_usf_up_l0_r(struct kobject *kobj,
+				       struct kobj_attribute *attr,
+				       const char *buf, size_t count)
+{
+	int val = 0;
+	int ret = 0;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val == 0) {
+		usf_vdev.sysctl_sched_usf_up_l0 = val;
+		usf_vdev.usf_up_l0 = 0;
+	} else if ((val > 0) && (val <= BOOST_MAX_V)) {
+		usf_vdev.sysctl_sched_usf_up_l0 = val;
+		usf_vdev.usf_up_l0 = LEVEL_TOP -
+				DIV_ROUND_UP(val, BOOST_MAX_V / 2);
+		ret = count
+	} else {
+		pr_err(USF_TAG "%d should fall into [%d %d]",
+		       val, 0, BOOST_MAX_V);
+		ret = -EINVAL;
+	}
+	if ((usf_vdev.sysctl_sched_usf_up_l0 == 0) &&
+	    (usf_vdev.sysctl_sched_usf_down == 0))
+		static_branch_disable(&adjust_task_pred_set);
+	else
+		static_branch_enable(&adjust_task_pred_set);
+
+	return ret;
+}
+
+static ssize_t store_sched_usf_down_r(struct kobject *kobj,
+				      struct kobj_attribute *attr,
+				      const char *buf, size_t count)
+{
+	int val = 0;
+	int ret = 0;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if ((val >= BOOST_MIN_V) && (val <= 0)) {
+		usf_vdev.sysctl_sched_usf_down = val;
+		usf_vdev.usf_down = DIV_ROUND_UP(-val, -BOOST_MIN_V / 2);
+		ret = count
+	} else {
+		pr_err(USF_TAG "%d should fall into [%d %d]",
+		       val, BOOST_MIN_V, 0);
+		ret = -EINVAL;
+	}
+	if ((usf_vdev.sysctl_sched_usf_up_l0 == 0) &&
+	    (usf_vdev.sysctl_sched_usf_down == 0))
+		static_branch_disable(&adjust_task_pred_set);
+	else
+		static_branch_enable(&adjust_task_pred_set);
+
+	return ret;
+}
+
+static ssize_t store_sched_usf_non_ux_r(struct kobject *kobj,
+					struct kobj_attribute *attr,
+					const char *buf, size_t count)
+{
+	int val = 0;
+	int ret = 0;
+
+	ret = kstrtoint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if ((val >= BOOST_MIN_V) && (val <= 0)) {
+		usf_vdev.sysctl_sched_usf_non_ux = val;
+		usf_vdev.usf_non_ux = DIV_ROUND_UP(-val, -BOOST_MIN_V / 2);
+		ret = count
+	} else {
+		pr_err(USF_TAG "%d should fall into [%d %d]",
+		       val, BOOST_MIN_V, 0);
+		ret = -EINVAL;
+	}
+	if (usf_vdev.sysctl_sched_usf_non_ux == 0)
+		static_branch_disable(&adjust_task_pred_set);
+	else
+		static_branch_enable(&adjust_task_pred_set);
+
+	return ret;
+}
+
+#define usf_attr_rw(_name)						\
+static struct kobj_attribute _name =					\
+__ATTR(_name, 0664, show_##_name, store_##_name)
+
+#define usf_show_node(_name, _value)					\
+static ssize_t show_##_name						\
+(struct kobject *kobj, struct kobj_attribute *attr,  char *buf)		\
+{									\
+	return sprintf(buf, "%d", usf_vdev.sysctl_##_value);		\
+}
+
+usf_show_node(sched_usf_up_l0_r, sched_usf_up_l0);
+usf_show_node(sched_usf_down_r, sched_usf_down);
+usf_show_node(sched_usf_non_ux_r, sched_usf_non_ux);
+
+usf_attr_rw(sched_usf_up_l0_r);
+usf_attr_rw(sched_usf_down_r);
+usf_attr_rw(sched_usf_non_ux_r);
+
+static struct attribute *sched_attrs[] = {
+	&sched_usf_up_l0_r.attr,
+	&sched_usf_down_r.attr,
+	&sched_usf_non_ux_r.attr,
+	NULL,
+};
+
+static struct attribute_group sched_attr_group = {
+	.attrs = sched_attrs,
+};
+
+static int __init intera_monitor_init(void)
+{
+	int res = -1;
+	struct attribute_group *attr_group;
+
+	res = fb_register_client(&usf_lcd_nb);
+	if (res < 0) {
+		pr_err("Failed to register usf_lcd_nb!\n");
+		return res;
+	}
+
+	/*
+	 * create a sched_usf in cpu_subsys:
+	 * /sys/devices/system/cpu/sched_usf/...
+	 */
+	attr_group = &sched_attr_group;
+	usf_vdev.kobj = kobject_create_and_add("sched_usf",
+					       &cpu_subsys.dev_root->kobj);
+
+	if (!usf_vdev.kobj) {
+		pr_err("Failed to create sched_usf!\n");
+		res = -ENOMEM;
+		goto out;
+	}
+	res = sysfs_create_group(usf_vdev.kobj, attr_group);
+	if (res) {
+		kobject_put(usf_vdev.kobj);
+		goto out;
+	}
+	kobject_uevent(usf_vdev.kobj, KOBJ_ADD);
+	static_branch_disable(&adjust_task_pred_set);
+
+	return 0;
+out:
+	fb_unregister_client(&usf_lcd_nb);
+	return res;
+}
+
+module_init(intera_monitor_init);
+
+static void __exit intera_monitor_exit(void)
+{
+	if (usf_vdev.kobj)
+		kobject_put(usf_vdev.kobj);
+	fb_unregister_client(&usf_lcd_nb);
+	static_branch_disable(&adjust_task_pred_set);
+}
+
+module_exit(intera_monitor_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("XiaoMi USF SCHED");
+MODULE_AUTHOR("Yang Dongdong <yangdongdong@...omi.com>");
-- 
2.7.4

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