linux-tkg/linux59-tkg/linux59-tkg-patches/0009-prjc_v5.9-r0.patch

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a1068742a6df..b97a9697fde4 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4611,6 +4611,12 @@
 
 	sbni=		[NET] Granch SBNI12 leased line adapter
 
+	sched_timeslice=
+			[KNL] Time slice in us for BMQ/PDS scheduler.
+			Format: <int> (must be >= 1000)
+			Default: 4000
+			See Documentation/scheduler/sched-BMQ.txt
+
 	sched_debug	[KNL] Enables verbose scheduler debug messages.
 
 	schedstats=	[KNL,X86] Enable or disable scheduled statistics.
diff --git a/Documentation/admin-guide/sysctl/kernel.rst b/Documentation/admin-guide/sysctl/kernel.rst
index d4b32cc32bb7..14118e5168ef 100644
--- a/Documentation/admin-guide/sysctl/kernel.rst
+++ b/Documentation/admin-guide/sysctl/kernel.rst
@@ -1515,3 +1515,13 @@ is 10 seconds.
 
 The softlockup threshold is (``2 * watchdog_thresh``). Setting this
 tunable to zero will disable lockup detection altogether.
+
+yield_type:
+===========
+
+BMQ/PDS CPU scheduler only. This determines what type of yield calls
+to sched_yield will perform.
+
+  0 - No yield.
+  1 - Deboost and requeue task. (default)
+  2 - Set run queue skip task.
diff --git a/Documentation/scheduler/sched-BMQ.txt b/Documentation/scheduler/sched-BMQ.txt
new file mode 100644
index 000000000000..05c84eec0f31
--- /dev/null
+++ b/Documentation/scheduler/sched-BMQ.txt
@@ -0,0 +1,110 @@
+                         BitMap queue CPU Scheduler
+                         --------------------------
+
+CONTENT
+========
+
+ Background
+ Design
+   Overview
+   Task policy
+   Priority management
+   BitMap Queue
+   CPU Assignment and Migration
+
+
+Background
+==========
+
+BitMap Queue CPU scheduler, referred to as BMQ from here on, is an evolution
+of previous Priority and Deadline based Skiplist multiple queue scheduler(PDS),
+and inspired by Zircon scheduler. The goal of it is to keep the scheduler code
+simple, while efficiency and scalable for interactive tasks, such as desktop,
+movie playback and gaming etc.
+
+Design
+======
+
+Overview
+--------
+
+BMQ use per CPU run queue design, each CPU(logical) has it's own run queue,
+each CPU is responsible for scheduling the tasks that are putting into it's
+run queue.
+
+The run queue is a set of priority queues. Note that these queues are fifo
+queue for non-rt tasks or priority queue for rt tasks in data structure. See
+BitMap Queue below for details. BMQ is optimized for non-rt tasks in the fact
+that most applications are non-rt tasks. No matter the queue is fifo or
+priority, In each queue is an ordered list of runnable tasks awaiting execution
+and the data structures are the same. When it is time for a new task to run,
+the scheduler simply looks the lowest numbered queueue that contains a task,
+and runs the first task from the head of that queue. And per CPU idle task is
+also in the run queue, so the scheduler can always find a task to run on from
+its run queue.
+
+Each task will assigned the same timeslice(default 4ms) when it is picked to
+start running. Task will be reinserted at the end of the appropriate priority
+queue when it uses its whole timeslice. When the scheduler selects a new task
+from the priority queue it sets the CPU's preemption timer for the remainder of
+the previous timeslice. When that timer fires the scheduler will stop execution
+on that task, select another task and start over again.
+
+If a task blocks waiting for a shared resource then it's taken out of its
+priority queue and is placed in a wait queue for the shared resource. When it
+is unblocked it will be reinserted in the appropriate priority queue of an
+eligible CPU.
+
+Task policy
+-----------
+
+BMQ supports DEADLINE, FIFO, RR, NORMAL, BATCH and IDLE task policy like the
+mainline CFS scheduler. But BMQ is heavy optimized for non-rt task, that's
+NORMAL/BATCH/IDLE policy tasks. Below is the implementation detail of each
+policy.
+
+DEADLINE
+	It is squashed as priority 0 FIFO task.
+
+FIFO/RR
+	All RT tasks share one single priority queue in BMQ run queue designed. The
+complexity of insert operation is O(n). BMQ is not designed for system runs
+with major rt policy tasks.
+
+NORMAL/BATCH/IDLE
+	BATCH and IDLE tasks are treated as the same policy. They compete CPU with
+NORMAL policy tasks, but they just don't boost. To control the priority of
+NORMAL/BATCH/IDLE tasks, simply use nice level.
+
+ISO
+	ISO policy is not supported in BMQ. Please use nice level -20 NORMAL policy
+task instead.
+
+Priority management
+-------------------
+
+RT tasks have priority from 0-99. For non-rt tasks, there are three different
+factors used to determine the effective priority of a task. The effective
+priority being what is used to determine which queue it will be in.
+
+The first factor is simply the task’s static priority. Which is assigned from
+task's nice level, within [-20, 19] in userland's point of view and [0, 39]
+internally.
+
+The second factor is the priority boost. This is a value bounded between
+[-MAX_PRIORITY_ADJ, MAX_PRIORITY_ADJ] used to offset the base priority, it is
+modified by the following cases:
+
+*When a thread has used up its entire timeslice, always deboost its boost by
+increasing by one.
+*When a thread gives up cpu control(voluntary or non-voluntary) to reschedule,
+and its switch-in time(time after last switch and run) below the thredhold
+based on its priority boost, will boost its boost by decreasing by one buti is
+capped at 0 (won’t go negative).
+
+The intent in this system is to ensure that interactive threads are serviced
+quickly. These are usually the threads that interact directly with the user
+and cause user-perceivable latency. These threads usually do little work and
+spend most of their time blocked awaiting another user event. So they get the
+priority boost from unblocking while background threads that do most of the
+processing receive the priority penalty for using their entire timeslice.
diff --git a/fs/proc/base.c b/fs/proc/base.c
index 617db4e0faa0..f85926764f9a 100644
--- a/fs/proc/base.c
+++ b/fs/proc/base.c
@@ -479,7 +479,7 @@ static int proc_pid_schedstat(struct seq_file *m, struct pid_namespace *ns,
 		seq_puts(m, "0 0 0\n");
 	else
 		seq_printf(m, "%llu %llu %lu\n",
-		   (unsigned long long)task->se.sum_exec_runtime,
+		   (unsigned long long)tsk_seruntime(task),
 		   (unsigned long long)task->sched_info.run_delay,
 		   task->sched_info.pcount);
 
diff --git a/include/asm-generic/resource.h b/include/asm-generic/resource.h
index 8874f681b056..59eb72bf7d5f 100644
--- a/include/asm-generic/resource.h
+++ b/include/asm-generic/resource.h
@@ -23,7 +23,7 @@
 	[RLIMIT_LOCKS]		= {  RLIM_INFINITY,  RLIM_INFINITY },	\
 	[RLIMIT_SIGPENDING]	= { 		0,	       0 },	\
 	[RLIMIT_MSGQUEUE]	= {   MQ_BYTES_MAX,   MQ_BYTES_MAX },	\
-	[RLIMIT_NICE]		= { 0, 0 },				\
+	[RLIMIT_NICE]		= { 30, 30 },				\
 	[RLIMIT_RTPRIO]		= { 0, 0 },				\
 	[RLIMIT_RTTIME]		= {  RLIM_INFINITY,  RLIM_INFINITY },	\
 }
diff --git a/include/linux/sched.h b/include/linux/sched.h
index afe01e232935..8918609cb9f0 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -34,6 +34,7 @@
 #include <linux/rseq.h>
 #include <linux/seqlock.h>
 #include <linux/kcsan.h>
+#include <linux/skip_list.h>
 
 /* task_struct member predeclarations (sorted alphabetically): */
 struct audit_context;
@@ -652,12 +653,18 @@ struct task_struct {
 	unsigned int			ptrace;
 
 #ifdef CONFIG_SMP
-	int				on_cpu;
 	struct __call_single_node	wake_entry;
+#endif
+#if defined(CONFIG_SMP) || defined(CONFIG_SCHED_ALT)
+	int				on_cpu;
+#endif
+
+#ifdef CONFIG_SMP
 #ifdef CONFIG_THREAD_INFO_IN_TASK
 	/* Current CPU: */
 	unsigned int			cpu;
 #endif
+#ifndef CONFIG_SCHED_ALT
 	unsigned int			wakee_flips;
 	unsigned long			wakee_flip_decay_ts;
 	struct task_struct		*last_wakee;
@@ -671,6 +678,7 @@ struct task_struct {
 	 */
 	int				recent_used_cpu;
 	int				wake_cpu;
+#endif /* !CONFIG_SCHED_ALT */
 #endif
 	int				on_rq;
 
@@ -679,13 +687,33 @@ struct task_struct {
 	int				normal_prio;
 	unsigned int			rt_priority;
 
+#ifdef CONFIG_SCHED_ALT
+	u64				last_ran;
+	s64				time_slice;
+#ifdef CONFIG_SCHED_BMQ
+	int				boost_prio;
+	int				bmq_idx;
+	struct list_head		bmq_node;
+#endif /* CONFIG_SCHED_BMQ */
+#ifdef CONFIG_SCHED_PDS
+	u64				deadline;
+	u64				priodl;
+	/* skip list level */
+	int				sl_level;
+	/* skip list node */
+	struct skiplist_node		sl_node;
+#endif /* CONFIG_SCHED_PDS */
+	/* sched_clock time spent running */
+	u64				sched_time;
+#else /* !CONFIG_SCHED_ALT */
 	const struct sched_class	*sched_class;
 	struct sched_entity		se;
 	struct sched_rt_entity		rt;
+	struct sched_dl_entity		dl;
+#endif
 #ifdef CONFIG_CGROUP_SCHED
 	struct task_group		*sched_task_group;
 #endif
-	struct sched_dl_entity		dl;
 
 #ifdef CONFIG_UCLAMP_TASK
 	/*
@@ -1332,6 +1360,15 @@ struct task_struct {
 	 */
 };
 
+#ifdef CONFIG_SCHED_ALT
+#define tsk_seruntime(t)		((t)->sched_time)
+/* replace the uncertian rt_timeout with 0UL */
+#define tsk_rttimeout(t)		(0UL)
+#else /* CFS */
+#define tsk_seruntime(t)	((t)->se.sum_exec_runtime)
+#define tsk_rttimeout(t)	((t)->rt.timeout)
+#endif /* !CONFIG_SCHED_ALT */
+
 static inline struct pid *task_pid(struct task_struct *task)
 {
 	return task->thread_pid;
diff --git a/include/linux/sched/deadline.h b/include/linux/sched/deadline.h
index 1aff00b65f3c..179d77c8360e 100644
--- a/include/linux/sched/deadline.h
+++ b/include/linux/sched/deadline.h
@@ -1,5 +1,24 @@
 /* SPDX-License-Identifier: GPL-2.0 */
 
+#ifdef CONFIG_SCHED_ALT
+
+static inline int dl_task(struct task_struct *p)
+{
+	return 0;
+}
+
+#ifdef CONFIG_SCHED_BMQ
+#define __tsk_deadline(p)	(0UL)
+#endif
+
+#ifdef CONFIG_SCHED_PDS
+#define __tsk_deadline(p)	((p)->priodl)
+#endif
+
+#else
+
+#define __tsk_deadline(p)	((p)->dl.deadline)
+
 /*
  * SCHED_DEADLINE tasks has negative priorities, reflecting
  * the fact that any of them has higher prio than RT and
@@ -19,6 +38,7 @@ static inline int dl_task(struct task_struct *p)
 {
 	return dl_prio(p->prio);
 }
+#endif /* CONFIG_SCHED_ALT */
 
 static inline bool dl_time_before(u64 a, u64 b)
 {
diff --git a/include/linux/sched/prio.h b/include/linux/sched/prio.h
index 7d64feafc408..42730d27ceb5 100644
--- a/include/linux/sched/prio.h
+++ b/include/linux/sched/prio.h
@@ -20,11 +20,20 @@
  */
 
 #define MAX_USER_RT_PRIO	100
+
 #define MAX_RT_PRIO		MAX_USER_RT_PRIO
 
 #define MAX_PRIO		(MAX_RT_PRIO + NICE_WIDTH)
 #define DEFAULT_PRIO		(MAX_RT_PRIO + NICE_WIDTH / 2)
 
+/* +/- priority levels from the base priority */
+#ifdef CONFIG_SCHED_BMQ
+#define MAX_PRIORITY_ADJ	7
+#endif
+#ifdef CONFIG_SCHED_PDS
+#define MAX_PRIORITY_ADJ	0
+#endif
+
 /*
  * Convert user-nice values [ -20 ... 0 ... 19 ]
  * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
diff --git a/include/linux/sched/rt.h b/include/linux/sched/rt.h
index e5af028c08b4..0a7565d0d3cf 100644
--- a/include/linux/sched/rt.h
+++ b/include/linux/sched/rt.h
@@ -24,8 +24,10 @@ static inline bool task_is_realtime(struct task_struct *tsk)
 
 	if (policy == SCHED_FIFO || policy == SCHED_RR)
 		return true;
+#ifndef CONFIG_SCHED_ALT
 	if (policy == SCHED_DEADLINE)
 		return true;
+#endif
 	return false;
 }
 
diff --git a/include/linux/skip_list.h b/include/linux/skip_list.h
new file mode 100644
index 000000000000..47ca955a451d
--- /dev/null
+++ b/include/linux/skip_list.h
@@ -0,0 +1,177 @@
+/*
+ * Copyright (C) 2016 Alfred Chen.
+ *
+ * Code based on Con Kolivas's skip list implementation for BFS, and
+ * which is based on example originally by William Pugh.
+ *
+ * Skip Lists are a probabilistic alternative to balanced trees, as
+ * described in the June 1990 issue of CACM and were invented by
+ * William Pugh in 1987.
+ *
+ * A couple of comments about this implementation:
+ *
+ * This file only provides a infrastructure of skip list.
+ *
+ * skiplist_node is embedded into container data structure, to get rid
+ * the dependency of kmalloc/kfree operation in scheduler code.
+ *
+ * A customized search function should be defined using DEFINE_SKIPLIST_INSERT
+ * macro and be used for skip list insert operation.
+ *
+ * Random Level is also not defined in this file, instead, it should be
+ * customized implemented and set to node->level then pass to the customized
+ * skiplist_insert function.
+ *
+ * Levels start at zero and go up to (NUM_SKIPLIST_LEVEL -1)
+ *
+ * NUM_SKIPLIST_LEVEL in this implementation is 8 instead of origin 16,
+ * considering that there will be 256 entries to enable the top level when using
+ * random level p=0.5, and that number is more than enough for a run queue usage
+ * in a scheduler usage. And it also help to reduce the memory usage of the
+ * embedded skip list node in task_struct to about 50%.
+ *
+ * The insertion routine has been implemented so as to use the
+ * dirty hack described in the CACM paper: if a random level is
+ * generated that is more than the current maximum level, the
+ * current maximum level plus one is used instead.
+ *
+ * BFS Notes: In this implementation of skiplists, there are bidirectional
+ * next/prev pointers and the insert function returns a pointer to the actual
+ * node the value is stored. The key here is chosen by the scheduler so as to
+ * sort tasks according to the priority list requirements and is no longer used
+ * by the scheduler after insertion. The scheduler lookup, however, occurs in
+ * O(1) time because it is always the first item in the level 0 linked list.
+ * Since the task struct stores a copy of the node pointer upon skiplist_insert,
+ * it can also remove it much faster than the original implementation with the
+ * aid of prev<->next pointer manipulation and no searching.
+ */
+#ifndef _LINUX_SKIP_LIST_H
+#define _LINUX_SKIP_LIST_H
+
+#include <linux/kernel.h>
+
+#define NUM_SKIPLIST_LEVEL (8)
+
+struct skiplist_node {
+	int level;	/* Levels in this node */
+	struct skiplist_node *next[NUM_SKIPLIST_LEVEL];
+	struct skiplist_node *prev[NUM_SKIPLIST_LEVEL];
+};
+
+#define SKIPLIST_NODE_INIT(name) { 0,\
+				   {&name, &name, &name, &name,\
+				    &name, &name, &name, &name},\
+				   {&name, &name, &name, &name,\
+				    &name, &name, &name, &name},\
+				 }
+
+static inline void INIT_SKIPLIST_NODE(struct skiplist_node *node)
+{
+	/* only level 0 ->next matters in skiplist_empty() */
+	WRITE_ONCE(node->next[0], node);
+}
+
+/**
+ * FULL_INIT_SKIPLIST_NODE -- fully init a skiplist_node, expecially for header
+ * @node: the skip list node to be inited.
+ */
+static inline void FULL_INIT_SKIPLIST_NODE(struct skiplist_node *node)
+{
+	int i;
+
+	node->level = 0;
+	for (i = 0; i < NUM_SKIPLIST_LEVEL; i++) {
+		WRITE_ONCE(node->next[i], node);
+		node->prev[i] = node;
+	}
+}
+
+/**
+ * skiplist_empty - test whether a skip list is empty
+ * @head: the skip list to test.
+ */
+static inline int skiplist_empty(const struct skiplist_node *head)
+{
+	return READ_ONCE(head->next[0]) == head;
+}
+
+/**
+ * skiplist_entry - get the struct for this entry
+ * @ptr: the &struct skiplist_node pointer.
+ * @type:       the type of the struct this is embedded in.
+ * @member:     the name of the skiplist_node within the struct.
+ */
+#define skiplist_entry(ptr, type, member) \
+	container_of(ptr, type, member)
+
+/**
+ * DEFINE_SKIPLIST_INSERT_FUNC -- macro to define a customized skip list insert
+ * function, which takes two parameters, first one is the header node of the
+ * skip list, second one is the skip list node to be inserted
+ * @func_name: the customized skip list insert function name
+ * @search_func: the search function to be used, which takes two parameters,
+ * 1st one is the itrator of skiplist_node in the list, the 2nd is the skip list
+ * node to be inserted, the function should return true if search should be
+ * continued, otherwise return false.
+ * Returns 1 if @node is inserted as the first item of skip list at level zero,
+ * otherwise 0
+ */
+#define DEFINE_SKIPLIST_INSERT_FUNC(func_name, search_func)\
+static inline int func_name(struct skiplist_node *head, struct skiplist_node *node)\
+{\
+	struct skiplist_node *update[NUM_SKIPLIST_LEVEL];\
+	struct skiplist_node *p, *q;\
+	int k = head->level;\
+\
+	p = head;\
+	do {\
+		while (q = p->next[k], q != head && search_func(q, node))\
+			p = q;\
+		update[k] = p;\
+	} while (--k >= 0);\
+\
+	k = node->level;\
+	if (unlikely(k > head->level)) {\
+		node->level = k = ++head->level;\
+		update[k] = head;\
+	}\
+\
+	do {\
+		p = update[k];\
+		q = p->next[k];\
+		node->next[k] = q;\
+		p->next[k] = node;\
+		node->prev[k] = p;\
+		q->prev[k] = node;\
+	} while (--k >= 0);\
+\
+	return (p == head);\
+}
+
+/**
+ * skiplist_del_init -- delete skip list node from a skip list and reset it's
+ * init state
+ * @head: the header node of the skip list to be deleted from.
+ * @node: the skip list node to be deleted, the caller need to ensure @node is
+ * in skip list which @head represent.
+ * Returns 1 if @node is the first item of skip level at level zero, otherwise 0
+ */
+static inline int
+skiplist_del_init(struct skiplist_node *head, struct skiplist_node *node)
+{
+	int l, m = node->level;
+
+	for (l = 0; l <= m; l++) {
+		node->prev[l]->next[l] = node->next[l];
+		node->next[l]->prev[l] = node->prev[l];
+	}
+	if (m == head->level && m > 0) {
+		while (head->next[m] == head && m > 0)
+			m--;
+		head->level = m;
+	}
+	INIT_SKIPLIST_NODE(node);
+
+	return (node->prev[0] == head);
+}
+#endif /* _LINUX_SKIP_LIST_H */
diff --git a/init/Kconfig b/init/Kconfig
index d6a0b31b13dc..2122dba5596f 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -770,9 +770,39 @@ config GENERIC_SCHED_CLOCK
 
 menu "Scheduler features"
 
+menuconfig SCHED_ALT
+	bool "Alternative CPU Schedulers"
+	default y
+	help
+	  This feature enable alternative CPU scheduler"
+
+if SCHED_ALT
+
+choice
+	prompt "Alternative CPU Scheduler"
+	default SCHED_BMQ
+
+config SCHED_BMQ
+	bool "BMQ CPU scheduler"
+	help
+	  The BitMap Queue CPU scheduler for excellent interactivity and
+	  responsiveness on the desktop and solid scalability on normal
+	  hardware and commodity servers.
+
+config SCHED_PDS
+	bool "PDS CPU scheduler"
+	help
+	  The Priority and Deadline based Skip list multiple queue CPU
+	  Scheduler.
+
+endchoice
+
+endif
+
 config UCLAMP_TASK
 	bool "Enable utilization clamping for RT/FAIR tasks"
 	depends on CPU_FREQ_GOV_SCHEDUTIL
+	depends on !SCHED_ALT
 	help
 	  This feature enables the scheduler to track the clamped utilization
 	  of each CPU based on RUNNABLE tasks scheduled on that CPU.
@@ -858,6 +888,7 @@ config NUMA_BALANCING
 	depends on ARCH_SUPPORTS_NUMA_BALANCING
 	depends on !ARCH_WANT_NUMA_VARIABLE_LOCALITY
 	depends on SMP && NUMA && MIGRATION
+	depends on !SCHED_ALT
 	help
 	  This option adds support for automatic NUMA aware memory/task placement.
 	  The mechanism is quite primitive and is based on migrating memory when
@@ -944,7 +975,7 @@ menuconfig CGROUP_SCHED
 	  bandwidth allocation to such task groups. It uses cgroups to group
 	  tasks.
 
-if CGROUP_SCHED
+if CGROUP_SCHED && !SCHED_ALT
 config FAIR_GROUP_SCHED
 	bool "Group scheduling for SCHED_OTHER"
 	depends on CGROUP_SCHED
@@ -1200,6 +1231,7 @@ config CHECKPOINT_RESTORE
 
 config SCHED_AUTOGROUP
 	bool "Automatic process group scheduling"
+	depends on !SCHED_ALT
 	select CGROUPS
 	select CGROUP_SCHED
 	select FAIR_GROUP_SCHED
diff --git a/init/init_task.c b/init/init_task.c
index f6889fce64af..5a23122f3d2c 100644
--- a/init/init_task.c
+++ b/init/init_task.c
@@ -75,9 +75,15 @@ struct task_struct init_task
 	.stack		= init_stack,
 	.usage		= REFCOUNT_INIT(2),
 	.flags		= PF_KTHREAD,
+#ifdef CONFIG_SCHED_ALT
+	.prio		= DEFAULT_PRIO + MAX_PRIORITY_ADJ,
+	.static_prio	= DEFAULT_PRIO,
+	.normal_prio	= DEFAULT_PRIO + MAX_PRIORITY_ADJ,
+#else
 	.prio		= MAX_PRIO - 20,
 	.static_prio	= MAX_PRIO - 20,
 	.normal_prio	= MAX_PRIO - 20,
+#endif
 	.policy		= SCHED_NORMAL,
 	.cpus_ptr	= &init_task.cpus_mask,
 	.cpus_mask	= CPU_MASK_ALL,
@@ -87,6 +93,19 @@ struct task_struct init_task
 	.restart_block	= {
 		.fn = do_no_restart_syscall,
 	},
+#ifdef CONFIG_SCHED_ALT
+#ifdef CONFIG_SCHED_BMQ
+	.boost_prio	= 0,
+	.bmq_idx	= 15,
+	.bmq_node	= LIST_HEAD_INIT(init_task.bmq_node),
+#endif
+#ifdef CONFIG_SCHED_PDS
+	.deadline	= 0,
+	.sl_level	= 0,
+	.sl_node	= SKIPLIST_NODE_INIT(init_task.sl_node),
+#endif
+	.time_slice	= HZ,
+#else
 	.se		= {
 		.group_node 	= LIST_HEAD_INIT(init_task.se.group_node),
 	},
@@ -94,6 +113,7 @@ struct task_struct init_task
 		.run_list	= LIST_HEAD_INIT(init_task.rt.run_list),
 		.time_slice	= RR_TIMESLICE,
 	},
+#endif
 	.tasks		= LIST_HEAD_INIT(init_task.tasks),
 #ifdef CONFIG_SMP
 	.pushable_tasks	= PLIST_NODE_INIT(init_task.pushable_tasks, MAX_PRIO),
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index 642415b8c3c9..7e0e1fe18035 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -636,7 +636,7 @@ static int validate_change(struct cpuset *cur, struct cpuset *trial)
 	return ret;
 }
 
-#ifdef CONFIG_SMP
+#if defined(CONFIG_SMP) && !defined(CONFIG_SCHED_ALT)
 /*
  * Helper routine for generate_sched_domains().
  * Do cpusets a, b have overlapping effective cpus_allowed masks?
@@ -1009,7 +1009,7 @@ static void rebuild_sched_domains_locked(void)
 	/* Have scheduler rebuild the domains */
 	partition_and_rebuild_sched_domains(ndoms, doms, attr);
 }
-#else /* !CONFIG_SMP */
+#else /* !CONFIG_SMP || CONFIG_SCHED_ALT */
 static void rebuild_sched_domains_locked(void)
 {
 }
diff --git a/kernel/delayacct.c b/kernel/delayacct.c
index 27725754ac99..769d773c7182 100644
--- a/kernel/delayacct.c
+++ b/kernel/delayacct.c
@@ -106,7 +106,7 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 	 */
 	t1 = tsk->sched_info.pcount;
 	t2 = tsk->sched_info.run_delay;
-	t3 = tsk->se.sum_exec_runtime;
+	t3 = tsk_seruntime(tsk);
 
 	d->cpu_count += t1;
 
diff --git a/kernel/exit.c b/kernel/exit.c
index 733e80f334e7..3f3506c851fd 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -121,7 +121,7 @@ static void __exit_signal(struct task_struct *tsk)
 			sig->curr_target = next_thread(tsk);
 	}
 
-	add_device_randomness((const void*) &tsk->se.sum_exec_runtime,
+	add_device_randomness((const void*) &tsk_seruntime(tsk),
 			      sizeof(unsigned long long));
 
 	/*
@@ -142,7 +142,7 @@ static void __exit_signal(struct task_struct *tsk)
 	sig->inblock += task_io_get_inblock(tsk);
 	sig->oublock += task_io_get_oublock(tsk);
 	task_io_accounting_add(&sig->ioac, &tsk->ioac);
-	sig->sum_sched_runtime += tsk->se.sum_exec_runtime;
+	sig->sum_sched_runtime += tsk_seruntime(tsk);
 	sig->nr_threads--;
 	__unhash_process(tsk, group_dead);
 	write_sequnlock(&sig->stats_lock);
diff --git a/kernel/livepatch/transition.c b/kernel/livepatch/transition.c
index f6310f848f34..4176ad070bc9 100644
--- a/kernel/livepatch/transition.c
+++ b/kernel/livepatch/transition.c
@@ -306,7 +306,11 @@ static bool klp_try_switch_task(struct task_struct *task)
 	 */
 	rq = task_rq_lock(task, &flags);
 
+#ifdef	CONFIG_SCHED_ALT
+	if (task_running(task) && task != current) {
+#else
 	if (task_running(rq, task) && task != current) {
+#endif
 		snprintf(err_buf, STACK_ERR_BUF_SIZE,
 			 "%s: %s:%d is running\n", __func__, task->comm,
 			 task->pid);
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index cfdd5b93264d..84c284eb544a 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -227,15 +227,19 @@ static inline bool unlock_rt_mutex_safe(struct rt_mutex *lock,
  * Only use with rt_mutex_waiter_{less,equal}()
  */
 #define task_to_waiter(p)	\
-	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = (p)->dl.deadline }
+	&(struct rt_mutex_waiter){ .prio = (p)->prio, .deadline = __tsk_deadline(p) }
 
 static inline int
 rt_mutex_waiter_less(struct rt_mutex_waiter *left,
 		     struct rt_mutex_waiter *right)
 {
+#ifdef CONFIG_SCHED_PDS
+	return (left->deadline < right->deadline);
+#else
 	if (left->prio < right->prio)
 		return 1;
 
+#ifndef CONFIG_SCHED_BMQ
 	/*
 	 * If both waiters have dl_prio(), we check the deadlines of the
 	 * associated tasks.
@@ -244,17 +248,23 @@ rt_mutex_waiter_less(struct rt_mutex_waiter *left,
 	 */
 	if (dl_prio(left->prio))
 		return dl_time_before(left->deadline, right->deadline);
+#endif
 
 	return 0;
+#endif
 }
 
 static inline int
 rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
 		      struct rt_mutex_waiter *right)
 {
+#ifdef CONFIG_SCHED_PDS
+	return (left->deadline == right->deadline);
+#else
 	if (left->prio != right->prio)
 		return 0;
 
+#ifndef CONFIG_SCHED_BMQ
 	/*
 	 * If both waiters have dl_prio(), we check the deadlines of the
 	 * associated tasks.
@@ -263,8 +273,10 @@ rt_mutex_waiter_equal(struct rt_mutex_waiter *left,
 	 */
 	if (dl_prio(left->prio))
 		return left->deadline == right->deadline;
+#endif
 
 	return 1;
+#endif
 }
 
 static void
@@ -678,7 +690,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
 	 * the values of the node being removed.
 	 */
 	waiter->prio = task->prio;
-	waiter->deadline = task->dl.deadline;
+	waiter->deadline = __tsk_deadline(task);
 
 	rt_mutex_enqueue(lock, waiter);
 
@@ -951,7 +963,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
 	waiter->task = task;
 	waiter->lock = lock;
 	waiter->prio = task->prio;
-	waiter->deadline = task->dl.deadline;
+	waiter->deadline = __tsk_deadline(task);
 
 	/* Get the top priority waiter on the lock */
 	if (rt_mutex_has_waiters(lock))
diff --git a/kernel/sched/Makefile b/kernel/sched/Makefile
index 5fc9c9b70862..eb6d7d87779f 100644
--- a/kernel/sched/Makefile
+++ b/kernel/sched/Makefile
@@ -22,14 +22,20 @@ ifneq ($(CONFIG_SCHED_OMIT_FRAME_POINTER),y)
 CFLAGS_core.o := $(PROFILING) -fno-omit-frame-pointer
 endif
 
-obj-y += core.o loadavg.o clock.o cputime.o
-obj-y += idle.o fair.o rt.o deadline.o
-obj-y += wait.o wait_bit.o swait.o completion.o
-
-obj-$(CONFIG_SMP) += cpupri.o cpudeadline.o topology.o stop_task.o pelt.o
+ifdef CONFIG_SCHED_ALT
+obj-y += alt_core.o alt_debug.o
+else
+obj-y += core.o
+obj-y += fair.o rt.o deadline.o
+obj-$(CONFIG_SMP) += cpudeadline.o stop_task.o
 obj-$(CONFIG_SCHED_AUTOGROUP) += autogroup.o
-obj-$(CONFIG_SCHEDSTATS) += stats.o
 obj-$(CONFIG_SCHED_DEBUG) += debug.o
+endif
+obj-y += loadavg.o clock.o cputime.o
+obj-y += idle.o
+obj-y += wait.o wait_bit.o swait.o completion.o
+obj-$(CONFIG_SMP) += cpupri.o pelt.o topology.o
+obj-$(CONFIG_SCHEDSTATS) += stats.o
 obj-$(CONFIG_CGROUP_CPUACCT) += cpuacct.o
 obj-$(CONFIG_CPU_FREQ) += cpufreq.o
 obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += cpufreq_schedutil.o
diff --git a/kernel/sched/alt_core.c b/kernel/sched/alt_core.c
new file mode 100644
index 000000000000..f36264fea75c
--- /dev/null
+++ b/kernel/sched/alt_core.c
@@ -0,0 +1,6360 @@
+/*
+ *  kernel/sched/alt_core.c
+ *
+ *  Core alternative kernel scheduler code and related syscalls
+ *
+ *  Copyright (C) 1991-2002  Linus Torvalds
+ *
+ *  2009-08-13	Brainfuck deadline scheduling policy by Con Kolivas deletes
+ *		a whole lot of those previous things.
+ *  2017-09-06	Priority and Deadline based Skip list multiple queue kernel
+ *		scheduler by Alfred Chen.
+ *  2019-02-20	BMQ(BitMap Queue) kernel scheduler by Alfred Chen.
+ */
+#include "sched.h"
+
+#include <linux/sched/rt.h>
+
+#include <linux/context_tracking.h>
+#include <linux/compat.h>
+#include <linux/blkdev.h>
+#include <linux/delayacct.h>
+#include <linux/freezer.h>
+#include <linux/init_task.h>
+#include <linux/kprobes.h>
+#include <linux/mmu_context.h>
+#include <linux/nmi.h>
+#include <linux/profile.h>
+#include <linux/rcupdate_wait.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/wait_bit.h>
+
+#include <linux/kcov.h>
+#include <linux/scs.h>
+
+#include <asm/switch_to.h>
+
+#include "../workqueue_internal.h"
+#include "../../fs/io-wq.h"
+#include "../smpboot.h"
+
+#include "pelt.h"
+#include "smp.h"
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/sched.h>
+
+#define ALT_SCHED_VERSION "v5.9-r0"
+
+/* rt_prio(prio) defined in include/linux/sched/rt.h */
+#define rt_task(p)		rt_prio((p)->prio)
+#define rt_policy(policy)	((policy) == SCHED_FIFO || (policy) == SCHED_RR)
+#define task_has_rt_policy(p)	(rt_policy((p)->policy))
+
+#define STOP_PRIO		(MAX_RT_PRIO - 1)
+
+/* Default time slice is 4 in ms, can be set via kernel parameter "sched_timeslice" */
+u64 sched_timeslice_ns __read_mostly = (4 * 1000 * 1000);
+
+static int __init sched_timeslice(char *str)
+{
+	int timeslice_us;
+
+	get_option(&str, &timeslice_us);
+	if (timeslice_us >= 1000)
+		sched_timeslice_ns = timeslice_us * 1000;
+
+	return 0;
+}
+early_param("sched_timeslice", sched_timeslice);
+
+/* Reschedule if less than this many μs left */
+#define RESCHED_NS		(100 * 1000)
+
+/**
+ * sched_yield_type - Choose what sort of yield sched_yield will perform.
+ * 0: No yield.
+ * 1: Deboost and requeue task. (default)
+ * 2: Set rq skip task.
+ */
+int sched_yield_type __read_mostly = 1;
+
+#ifdef CONFIG_SMP
+static cpumask_t sched_rq_pending_mask ____cacheline_aligned_in_smp;
+
+DEFINE_PER_CPU(cpumask_t [NR_CPU_AFFINITY_CHK_LEVEL], sched_cpu_affinity_masks);
+DEFINE_PER_CPU(cpumask_t *, sched_cpu_affinity_end_mask);
+DEFINE_PER_CPU(cpumask_t *, sched_cpu_llc_mask);
+
+#ifdef CONFIG_SCHED_SMT
+DEFINE_STATIC_KEY_FALSE(sched_smt_present);
+EXPORT_SYMBOL_GPL(sched_smt_present);
+#endif
+
+/*
+ * Keep a unique ID per domain (we use the first CPUs number in the cpumask of
+ * the domain), this allows us to quickly tell if two cpus are in the same cache
+ * domain, see cpus_share_cache().
+ */
+DEFINE_PER_CPU(int, sd_llc_id);
+#endif /* CONFIG_SMP */
+
+static DEFINE_MUTEX(sched_hotcpu_mutex);
+
+DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+
+#ifndef prepare_arch_switch
+# define prepare_arch_switch(next)	do { } while (0)
+#endif
+#ifndef finish_arch_post_lock_switch
+# define finish_arch_post_lock_switch()	do { } while (0)
+#endif
+
+#define IDLE_WM	(IDLE_TASK_SCHED_PRIO)
+
+#ifdef CONFIG_SCHED_SMT
+static cpumask_t sched_sg_idle_mask ____cacheline_aligned_in_smp;
+#endif
+static cpumask_t sched_rq_watermark[SCHED_BITS] ____cacheline_aligned_in_smp;
+
+#ifdef CONFIG_SCHED_BMQ
+#include "bmq_imp.h"
+#endif
+#ifdef CONFIG_SCHED_PDS
+#include "pds_imp.h"
+#endif
+
+static inline void update_sched_rq_watermark(struct rq *rq)
+{
+	unsigned long watermark = sched_queue_watermark(rq);
+	unsigned long last_wm = rq->watermark;
+	unsigned long i;
+	int cpu;
+
+	/*printk(KERN_INFO "sched: watermark(%d) %d, last %d\n",
+	       cpu_of(rq), watermark, last_wm);*/
+	if (watermark == last_wm)
+		return;
+
+	rq->watermark = watermark;
+	cpu = cpu_of(rq);
+	if (watermark < last_wm) {
+		for (i = watermark + 1; i <= last_wm; i++)
+			cpumask_andnot(&sched_rq_watermark[i],
+				       &sched_rq_watermark[i], cpumask_of(cpu));
+#ifdef CONFIG_SCHED_SMT
+		if (!static_branch_likely(&sched_smt_present))
+			return;
+		if (IDLE_WM == last_wm)
+			cpumask_andnot(&sched_sg_idle_mask,
+				       &sched_sg_idle_mask, cpu_smt_mask(cpu));
+#endif
+		return;
+	}
+	/* last_wm < watermark */
+	for (i = last_wm + 1; i <= watermark; i++)
+		cpumask_set_cpu(cpu, &sched_rq_watermark[i]);
+#ifdef CONFIG_SCHED_SMT
+	if (!static_branch_likely(&sched_smt_present))
+		return;
+	if (IDLE_WM == watermark) {
+		cpumask_t tmp;
+		cpumask_and(&tmp, cpu_smt_mask(cpu), &sched_rq_watermark[IDLE_WM]);
+		if (cpumask_equal(&tmp, cpu_smt_mask(cpu)))
+			cpumask_or(&sched_sg_idle_mask, cpu_smt_mask(cpu),
+				   &sched_sg_idle_mask);
+	}
+#endif
+}
+
+static inline struct task_struct *rq_runnable_task(struct rq *rq)
+{
+	struct task_struct *next = sched_rq_first_task(rq);
+
+	if (unlikely(next == rq->skip))
+		next = sched_rq_next_task(next, rq);
+
+	return next;
+}
+
+/*
+ * Serialization rules:
+ *
+ * Lock order:
+ *
+ *   p->pi_lock
+ *     rq->lock
+ *       hrtimer_cpu_base->lock (hrtimer_start() for bandwidth controls)
+ *
+ *  rq1->lock
+ *    rq2->lock  where: rq1 < rq2
+ *
+ * Regular state:
+ *
+ * Normal scheduling state is serialized by rq->lock. __schedule() takes the
+ * local CPU's rq->lock, it optionally removes the task from the runqueue and
+ * always looks at the local rq data structures to find the most elegible task
+ * to run next.
+ *
+ * Task enqueue is also under rq->lock, possibly taken from another CPU.
+ * Wakeups from another LLC domain might use an IPI to transfer the enqueue to
+ * the local CPU to avoid bouncing the runqueue state around [ see
+ * ttwu_queue_wakelist() ]
+ *
+ * Task wakeup, specifically wakeups that involve migration, are horribly
+ * complicated to avoid having to take two rq->locks.
+ *
+ * Special state:
+ *
+ * System-calls and anything external will use task_rq_lock() which acquires
+ * both p->pi_lock and rq->lock. As a consequence the state they change is
+ * stable while holding either lock:
+ *
+ *  - sched_setaffinity()/
+ *    set_cpus_allowed_ptr():	p->cpus_ptr, p->nr_cpus_allowed
+ *  - set_user_nice():		p->se.load, p->*prio
+ *  - __sched_setscheduler():	p->sched_class, p->policy, p->*prio,
+ *				p->se.load, p->rt_priority,
+ *				p->dl.dl_{runtime, deadline, period, flags, bw, density}
+ *  - sched_setnuma():		p->numa_preferred_nid
+ *  - sched_move_task()/
+ *    cpu_cgroup_fork():	p->sched_task_group
+ *  - uclamp_update_active()	p->uclamp*
+ *
+ * p->state <- TASK_*:
+ *
+ *   is changed locklessly using set_current_state(), __set_current_state() or
+ *   set_special_state(), see their respective comments, or by
+ *   try_to_wake_up(). This latter uses p->pi_lock to serialize against
+ *   concurrent self.
+ *
+ * p->on_rq <- { 0, 1 = TASK_ON_RQ_QUEUED, 2 = TASK_ON_RQ_MIGRATING }:
+ *
+ *   is set by activate_task() and cleared by deactivate_task(), under
+ *   rq->lock. Non-zero indicates the task is runnable, the special
+ *   ON_RQ_MIGRATING state is used for migration without holding both
+ *   rq->locks. It indicates task_cpu() is not stable, see task_rq_lock().
+ *
+ * p->on_cpu <- { 0, 1 }:
+ *
+ *   is set by prepare_task() and cleared by finish_task() such that it will be
+ *   set before p is scheduled-in and cleared after p is scheduled-out, both
+ *   under rq->lock. Non-zero indicates the task is running on its CPU.
+ *
+ *   [ The astute reader will observe that it is possible for two tasks on one
+ *     CPU to have ->on_cpu = 1 at the same time. ]
+ *
+ * task_cpu(p): is changed by set_task_cpu(), the rules are:
+ *
+ *  - Don't call set_task_cpu() on a blocked task:
+ *
+ *    We don't care what CPU we're not running on, this simplifies hotplug,
+ *    the CPU assignment of blocked tasks isn't required to be valid.
+ *
+ *  - for try_to_wake_up(), called under p->pi_lock:
+ *
+ *    This allows try_to_wake_up() to only take one rq->lock, see its comment.
+ *
+ *  - for migration called under rq->lock:
+ *    [ see task_on_rq_migrating() in task_rq_lock() ]
+ *
+ *    o move_queued_task()
+ *    o detach_task()
+ *
+ *  - for migration called under double_rq_lock():
+ *
+ *    o __migrate_swap_task()
+ *    o push_rt_task() / pull_rt_task()
+ *    o push_dl_task() / pull_dl_task()
+ *    o dl_task_offline_migration()
+ *
+ */
+
+/*
+ * Context: p->pi_lock
+ */
+static inline struct rq
+*__task_access_lock(struct task_struct *p, raw_spinlock_t **plock)
+{
+	struct rq *rq;
+	for (;;) {
+		rq = task_rq(p);
+		if (p->on_cpu || task_on_rq_queued(p)) {
+			raw_spin_lock(&rq->lock);
+			if (likely((p->on_cpu || task_on_rq_queued(p))
+				   && rq == task_rq(p))) {
+				*plock = &rq->lock;
+				return rq;
+			}
+			raw_spin_unlock(&rq->lock);
+		} else if (task_on_rq_migrating(p)) {
+			do {
+				cpu_relax();
+			} while (unlikely(task_on_rq_migrating(p)));
+		} else {
+			*plock = NULL;
+			return rq;
+		}
+	}
+}
+
+static inline void
+__task_access_unlock(struct task_struct *p, raw_spinlock_t *lock)
+{
+	if (NULL != lock)
+		raw_spin_unlock(lock);
+}
+
+static inline struct rq
+*task_access_lock_irqsave(struct task_struct *p, raw_spinlock_t **plock,
+			  unsigned long *flags)
+{
+	struct rq *rq;
+	for (;;) {
+		rq = task_rq(p);
+		if (p->on_cpu || task_on_rq_queued(p)) {
+			raw_spin_lock_irqsave(&rq->lock, *flags);
+			if (likely((p->on_cpu || task_on_rq_queued(p))
+				   && rq == task_rq(p))) {
+				*plock = &rq->lock;
+				return rq;
+			}
+			raw_spin_unlock_irqrestore(&rq->lock, *flags);
+		} else if (task_on_rq_migrating(p)) {
+			do {
+				cpu_relax();
+			} while (unlikely(task_on_rq_migrating(p)));
+		} else {
+			raw_spin_lock_irqsave(&p->pi_lock, *flags);
+			if (likely(!p->on_cpu && !p->on_rq &&
+				   rq == task_rq(p))) {
+				*plock = &p->pi_lock;
+				return rq;
+			}
+			raw_spin_unlock_irqrestore(&p->pi_lock, *flags);
+		}
+	}
+}
+
+static inline void
+task_access_unlock_irqrestore(struct task_struct *p, raw_spinlock_t *lock,
+			      unsigned long *flags)
+{
+	raw_spin_unlock_irqrestore(lock, *flags);
+}
+
+/*
+ * __task_rq_lock - lock the rq @p resides on.
+ */
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	lockdep_assert_held(&p->pi_lock);
+
+	for (;;) {
+		rq = task_rq(p);
+		raw_spin_lock(&rq->lock);
+		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p)))
+			return rq;
+		raw_spin_unlock(&rq->lock);
+
+		while (unlikely(task_on_rq_migrating(p)))
+			cpu_relax();
+	}
+}
+
+/*
+ * task_rq_lock - lock p->pi_lock and lock the rq @p resides on.
+ */
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(p->pi_lock)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	for (;;) {
+		raw_spin_lock_irqsave(&p->pi_lock, rf->flags);
+		rq = task_rq(p);
+		raw_spin_lock(&rq->lock);
+		/*
+		 *	move_queued_task()		task_rq_lock()
+		 *
+		 *	ACQUIRE (rq->lock)
+		 *	[S] ->on_rq = MIGRATING		[L] rq = task_rq()
+		 *	WMB (__set_task_cpu())		ACQUIRE (rq->lock);
+		 *	[S] ->cpu = new_cpu		[L] task_rq()
+		 *					[L] ->on_rq
+		 *	RELEASE (rq->lock)
+		 *
+		 * If we observe the old CPU in task_rq_lock(), the acquire of
+		 * the old rq->lock will fully serialize against the stores.
+		 *
+		 * If we observe the new CPU in task_rq_lock(), the address
+		 * dependency headed by '[L] rq = task_rq()' and the acquire
+		 * will pair with the WMB to ensure we then also see migrating.
+		 */
+		if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) {
+			return rq;
+		}
+		raw_spin_unlock(&rq->lock);
+		raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
+
+		while (unlikely(task_on_rq_migrating(p)))
+			cpu_relax();
+	}
+}
+
+static inline void
+rq_lock_irqsave(struct rq *rq, struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	raw_spin_lock_irqsave(&rq->lock, rf->flags);
+}
+
+static inline void
+rq_unlock_irqrestore(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	raw_spin_unlock_irqrestore(&rq->lock, rf->flags);
+}
+
+/*
+ * RQ-clock updating methods:
+ */
+
+static void update_rq_clock_task(struct rq *rq, s64 delta)
+{
+/*
+ * In theory, the compile should just see 0 here, and optimize out the call
+ * to sched_rt_avg_update. But I don't trust it...
+ */
+	s64 __maybe_unused steal = 0, irq_delta = 0;
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time;
+
+	/*
+	 * Since irq_time is only updated on {soft,}irq_exit, we might run into
+	 * this case when a previous update_rq_clock() happened inside a
+	 * {soft,}irq region.
+	 *
+	 * When this happens, we stop ->clock_task and only update the
+	 * prev_irq_time stamp to account for the part that fit, so that a next
+	 * update will consume the rest. This ensures ->clock_task is
+	 * monotonic.
+	 *
+	 * It does however cause some slight miss-attribution of {soft,}irq
+	 * time, a more accurate solution would be to update the irq_time using
+	 * the current rq->clock timestamp, except that would require using
+	 * atomic ops.
+	 */
+	if (irq_delta > delta)
+		irq_delta = delta;
+
+	rq->prev_irq_time += irq_delta;
+	delta -= irq_delta;
+#endif
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	if (static_key_false((&paravirt_steal_rq_enabled))) {
+		steal = paravirt_steal_clock(cpu_of(rq));
+		steal -= rq->prev_steal_time_rq;
+
+		if (unlikely(steal > delta))
+			steal = delta;
+
+		rq->prev_steal_time_rq += steal;
+		delta -= steal;
+	}
+#endif
+
+	rq->clock_task += delta;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	if ((irq_delta + steal))
+		update_irq_load_avg(rq, irq_delta + steal);
+#endif
+}
+
+static inline void update_rq_clock(struct rq *rq)
+{
+	s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;
+
+	if (unlikely(delta <= 0))
+		return;
+	rq->clock += delta;
+	update_rq_clock_task(rq, delta);
+}
+
+#ifdef CONFIG_NO_HZ_FULL
+/*
+ * Tick may be needed by tasks in the runqueue depending on their policy and
+ * requirements. If tick is needed, lets send the target an IPI to kick it out
+ * of nohz mode if necessary.
+ */
+static inline void sched_update_tick_dependency(struct rq *rq)
+{
+	int cpu = cpu_of(rq);
+
+	if (!tick_nohz_full_cpu(cpu))
+		return;
+
+	if (rq->nr_running < 2)
+		tick_nohz_dep_clear_cpu(cpu, TICK_DEP_BIT_SCHED);
+	else
+		tick_nohz_dep_set_cpu(cpu, TICK_DEP_BIT_SCHED);
+}
+#else /* !CONFIG_NO_HZ_FULL */
+static inline void sched_update_tick_dependency(struct rq *rq) { }
+#endif
+
+/*
+ * Add/Remove/Requeue task to/from the runqueue routines
+ * Context: rq->lock
+ */
+static inline void dequeue_task(struct task_struct *p, struct rq *rq, int flags)
+{
+	lockdep_assert_held(&rq->lock);
+
+	/*printk(KERN_INFO "sched: dequeue(%d) %px %016llx\n", cpu_of(rq), p, p->priodl);*/
+	WARN_ONCE(task_rq(p) != rq, "sched: dequeue task reside on cpu%d from cpu%d\n",
+		  task_cpu(p), cpu_of(rq));
+
+	__SCHED_DEQUEUE_TASK(p, rq, flags, update_sched_rq_watermark(rq));
+	--rq->nr_running;
+#ifdef CONFIG_SMP
+	if (1 == rq->nr_running)
+		cpumask_clear_cpu(cpu_of(rq), &sched_rq_pending_mask);
+#endif
+
+	sched_update_tick_dependency(rq);
+}
+
+static inline void enqueue_task(struct task_struct *p, struct rq *rq, int flags)
+{
+	lockdep_assert_held(&rq->lock);
+
+	/*printk(KERN_INFO "sched: enqueue(%d) %px %016llx\n", cpu_of(rq), p, p->priodl);*/
+	WARN_ONCE(task_rq(p) != rq, "sched: enqueue task reside on cpu%d to cpu%d\n",
+		  task_cpu(p), cpu_of(rq));
+
+	__SCHED_ENQUEUE_TASK(p, rq, flags);
+	update_sched_rq_watermark(rq);
+	++rq->nr_running;
+#ifdef CONFIG_SMP
+	if (2 == rq->nr_running)
+		cpumask_set_cpu(cpu_of(rq), &sched_rq_pending_mask);
+#endif
+
+	sched_update_tick_dependency(rq);
+
+	/*
+	 * If in_iowait is set, the code below may not trigger any cpufreq
+	 * utilization updates, so do it here explicitly with the IOWAIT flag
+	 * passed.
+	 */
+	if (p->in_iowait)
+		cpufreq_update_util(rq, SCHED_CPUFREQ_IOWAIT);
+}
+
+static inline void requeue_task(struct task_struct *p, struct rq *rq)
+{
+	lockdep_assert_held(&rq->lock);
+	/*printk(KERN_INFO "sched: requeue(%d) %px %016llx\n", cpu_of(rq), p, p->priodl);*/
+	WARN_ONCE(task_rq(p) != rq, "sched: cpu[%d] requeue task reside on cpu%d\n",
+		  cpu_of(rq), task_cpu(p));
+
+	__SCHED_REQUEUE_TASK(p, rq, update_sched_rq_watermark(rq));
+}
+
+/*
+ * cmpxchg based fetch_or, macro so it works for different integer types
+ */
+#define fetch_or(ptr, mask)						\
+	({								\
+		typeof(ptr) _ptr = (ptr);				\
+		typeof(mask) _mask = (mask);				\
+		typeof(*_ptr) _old, _val = *_ptr;			\
+									\
+		for (;;) {						\
+			_old = cmpxchg(_ptr, _val, _val | _mask);	\
+			if (_old == _val)				\
+				break;					\
+			_val = _old;					\
+		}							\
+	_old;								\
+})
+
+#if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG)
+/*
+ * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG,
+ * this avoids any races wrt polling state changes and thereby avoids
+ * spurious IPIs.
+ */
+static bool set_nr_and_not_polling(struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG);
+}
+
+/*
+ * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set.
+ *
+ * If this returns true, then the idle task promises to call
+ * sched_ttwu_pending() and reschedule soon.
+ */
+static bool set_nr_if_polling(struct task_struct *p)
+{
+	struct thread_info *ti = task_thread_info(p);
+	typeof(ti->flags) old, val = READ_ONCE(ti->flags);
+
+	for (;;) {
+		if (!(val & _TIF_POLLING_NRFLAG))
+			return false;
+		if (val & _TIF_NEED_RESCHED)
+			return true;
+		old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED);
+		if (old == val)
+			break;
+		val = old;
+	}
+	return true;
+}
+
+#else
+static bool set_nr_and_not_polling(struct task_struct *p)
+{
+	set_tsk_need_resched(p);
+	return true;
+}
+
+#ifdef CONFIG_SMP
+static bool set_nr_if_polling(struct task_struct *p)
+{
+	return false;
+}
+#endif
+#endif
+
+static bool __wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	struct wake_q_node *node = &task->wake_q;
+
+	/*
+	 * Atomically grab the task, if ->wake_q is !nil already it means
+	 * its already queued (either by us or someone else) and will get the
+	 * wakeup due to that.
+	 *
+	 * In order to ensure that a pending wakeup will observe our pending
+	 * state, even in the failed case, an explicit smp_mb() must be used.
+	 */
+	smp_mb__before_atomic();
+	if (unlikely(cmpxchg_relaxed(&node->next, NULL, WAKE_Q_TAIL)))
+		return false;
+
+	/*
+	 * The head is context local, there can be no concurrency.
+	 */
+	*head->lastp = node;
+	head->lastp = &node->next;
+	return true;
+}
+
+/**
+ * wake_q_add() - queue a wakeup for 'later' waking.
+ * @head: the wake_q_head to add @task to
+ * @task: the task to queue for 'later' wakeup
+ *
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
+ * instantly.
+ *
+ * This function must be used as-if it were wake_up_process(); IOW the task
+ * must be ready to be woken at this location.
+ */
+void wake_q_add(struct wake_q_head *head, struct task_struct *task)
+{
+	if (__wake_q_add(head, task))
+		get_task_struct(task);
+}
+
+/**
+ * wake_q_add_safe() - safely queue a wakeup for 'later' waking.
+ * @head: the wake_q_head to add @task to
+ * @task: the task to queue for 'later' wakeup
+ *
+ * Queue a task for later wakeup, most likely by the wake_up_q() call in the
+ * same context, _HOWEVER_ this is not guaranteed, the wakeup can come
+ * instantly.
+ *
+ * This function must be used as-if it were wake_up_process(); IOW the task
+ * must be ready to be woken at this location.
+ *
+ * This function is essentially a task-safe equivalent to wake_q_add(). Callers
+ * that already hold reference to @task can call the 'safe' version and trust
+ * wake_q to do the right thing depending whether or not the @task is already
+ * queued for wakeup.
+ */
+void wake_q_add_safe(struct wake_q_head *head, struct task_struct *task)
+{
+	if (!__wake_q_add(head, task))
+		put_task_struct(task);
+}
+
+void wake_up_q(struct wake_q_head *head)
+{
+	struct wake_q_node *node = head->first;
+
+	while (node != WAKE_Q_TAIL) {
+		struct task_struct *task;
+
+		task = container_of(node, struct task_struct, wake_q);
+		BUG_ON(!task);
+		/* task can safely be re-inserted now: */
+		node = node->next;
+		task->wake_q.next = NULL;
+
+		/*
+		 * wake_up_process() executes a full barrier, which pairs with
+		 * the queueing in wake_q_add() so as not to miss wakeups.
+		 */
+		wake_up_process(task);
+		put_task_struct(task);
+	}
+}
+
+/*
+ * resched_curr - mark rq's current task 'to be rescheduled now'.
+ *
+ * On UP this means the setting of the need_resched flag, on SMP it
+ * might also involve a cross-CPU call to trigger the scheduler on
+ * the target CPU.
+ */
+void resched_curr(struct rq *rq)
+{
+	struct task_struct *curr = rq->curr;
+	int cpu;
+
+	lockdep_assert_held(&rq->lock);
+
+	if (test_tsk_need_resched(curr))
+		return;
+
+	cpu = cpu_of(rq);
+	if (cpu == smp_processor_id()) {
+		set_tsk_need_resched(curr);
+		set_preempt_need_resched();
+		return;
+	}
+
+	if (set_nr_and_not_polling(curr))
+		smp_send_reschedule(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+void resched_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	raw_spin_lock_irqsave(&rq->lock, flags);
+	if (cpu_online(cpu) || cpu == smp_processor_id())
+		resched_curr(cpu_rq(cpu));
+	raw_spin_unlock_irqrestore(&rq->lock, flags);
+}
+
+#ifdef CONFIG_SMP
+#ifdef CONFIG_NO_HZ_COMMON
+void nohz_balance_enter_idle(int cpu) {}
+
+void select_nohz_load_balancer(int stop_tick) {}
+
+void set_cpu_sd_state_idle(void) {}
+
+/*
+ * In the semi idle case, use the nearest busy CPU for migrating timers
+ * from an idle CPU.  This is good for power-savings.
+ *
+ * We don't do similar optimization for completely idle system, as
+ * selecting an idle CPU will add more delays to the timers than intended
+ * (as that CPU's timer base may not be uptodate wrt jiffies etc).
+ */
+int get_nohz_timer_target(void)
+{
+	int i, cpu = smp_processor_id(), default_cpu = -1;
+	struct cpumask *mask;
+
+	if (housekeeping_cpu(cpu, HK_FLAG_TIMER)) {
+		if (!idle_cpu(cpu))
+			return cpu;
+		default_cpu = cpu;
+	}
+
+	for (mask = &(per_cpu(sched_cpu_affinity_masks, cpu)[0]);
+	     mask < per_cpu(sched_cpu_affinity_end_mask, cpu); mask++)
+		for_each_cpu_and(i, mask, housekeeping_cpumask(HK_FLAG_TIMER))
+			if (!idle_cpu(i))
+				return i;
+
+	if (default_cpu == -1)
+		default_cpu = housekeeping_any_cpu(HK_FLAG_TIMER);
+	cpu = default_cpu;
+
+	return cpu;
+}
+
+/*
+ * When add_timer_on() enqueues a timer into the timer wheel of an
+ * idle CPU then this timer might expire before the next timer event
+ * which is scheduled to wake up that CPU. In case of a completely
+ * idle system the next event might even be infinite time into the
+ * future. wake_up_idle_cpu() ensures that the CPU is woken up and
+ * leaves the inner idle loop so the newly added timer is taken into
+ * account when the CPU goes back to idle and evaluates the timer
+ * wheel for the next timer event.
+ */
+static inline void wake_up_idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (cpu == smp_processor_id())
+		return;
+
+	if (set_nr_and_not_polling(rq->idle))
+		smp_send_reschedule(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+static inline bool wake_up_full_nohz_cpu(int cpu)
+{
+	/*
+	 * We just need the target to call irq_exit() and re-evaluate
+	 * the next tick. The nohz full kick at least implies that.
+	 * If needed we can still optimize that later with an
+	 * empty IRQ.
+	 */
+	if (cpu_is_offline(cpu))
+		return true;  /* Don't try to wake offline CPUs. */
+	if (tick_nohz_full_cpu(cpu)) {
+		if (cpu != smp_processor_id() ||
+		    tick_nohz_tick_stopped())
+			tick_nohz_full_kick_cpu(cpu);
+		return true;
+	}
+
+	return false;
+}
+
+void wake_up_nohz_cpu(int cpu)
+{
+	if (!wake_up_full_nohz_cpu(cpu))
+		wake_up_idle_cpu(cpu);
+}
+
+static void nohz_csd_func(void *info)
+{
+	struct rq *rq = info;
+	int cpu = cpu_of(rq);
+	unsigned int flags;
+
+	/*
+	 * Release the rq::nohz_csd.
+	 */
+	flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(cpu));
+	WARN_ON(!(flags & NOHZ_KICK_MASK));
+
+	rq->idle_balance = idle_cpu(cpu);
+	if (rq->idle_balance && !need_resched()) {
+		rq->nohz_idle_balance = flags;
+		raise_softirq_irqoff(SCHED_SOFTIRQ);
+	}
+}
+
+#endif /* CONFIG_NO_HZ_COMMON */
+#endif /* CONFIG_SMP */
+
+static inline void check_preempt_curr(struct rq *rq)
+{
+	if (sched_rq_first_task(rq) != rq->curr)
+		resched_curr(rq);
+}
+
+static inline void
+rq_csd_init(struct rq *rq, call_single_data_t *csd, smp_call_func_t func)
+{
+	csd->flags = 0;
+	csd->func = func;
+	csd->info = rq;
+}
+
+#ifdef CONFIG_SCHED_HRTICK
+/*
+ * Use HR-timers to deliver accurate preemption points.
+ */
+
+static void hrtick_clear(struct rq *rq)
+{
+	if (hrtimer_active(&rq->hrtick_timer))
+		hrtimer_cancel(&rq->hrtick_timer);
+}
+
+/*
+ * High-resolution timer tick.
+ * Runs from hardirq context with interrupts disabled.
+ */
+static enum hrtimer_restart hrtick(struct hrtimer *timer)
+{
+	struct rq *rq = container_of(timer, struct rq, hrtick_timer);
+	struct task_struct *p;
+
+	WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
+
+	raw_spin_lock(&rq->lock);
+	p = rq->curr;
+	p->time_slice = 0;
+	resched_curr(rq);
+	raw_spin_unlock(&rq->lock);
+
+	return HRTIMER_NORESTART;
+}
+
+/*
+ * Use hrtick when:
+ *  - enabled by features
+ *  - hrtimer is actually high res
+ */
+static inline int hrtick_enabled(struct rq *rq)
+{
+	/**
+	 * Alt schedule FW doesn't support sched_feat yet
+	if (!sched_feat(HRTICK))
+		return 0;
+	*/
+	if (!cpu_active(cpu_of(rq)))
+		return 0;
+	return hrtimer_is_hres_active(&rq->hrtick_timer);
+}
+
+#ifdef CONFIG_SMP
+
+static void __hrtick_restart(struct rq *rq)
+{
+	struct hrtimer *timer = &rq->hrtick_timer;
+
+	hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
+}
+
+/*
+ * called from hardirq (IPI) context
+ */
+static void __hrtick_start(void *arg)
+{
+	struct rq *rq = arg;
+
+	raw_spin_lock(&rq->lock);
+	__hrtick_restart(rq);
+	raw_spin_unlock(&rq->lock);
+}
+
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+void hrtick_start(struct rq *rq, u64 delay)
+{
+	struct hrtimer *timer = &rq->hrtick_timer;
+	ktime_t time;
+	s64 delta;
+
+	/*
+	 * Don't schedule slices shorter than 10000ns, that just
+	 * doesn't make sense and can cause timer DoS.
+	 */
+	delta = max_t(s64, delay, 10000LL);
+	time = ktime_add_ns(timer->base->get_time(), delta);
+
+	hrtimer_set_expires(timer, time);
+
+	if (rq == this_rq())
+		__hrtick_restart(rq);
+	else
+		smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd);
+}
+
+#else
+/*
+ * Called to set the hrtick timer state.
+ *
+ * called with rq->lock held and irqs disabled
+ */
+void hrtick_start(struct rq *rq, u64 delay)
+{
+	/*
+	 * Don't schedule slices shorter than 10000ns, that just
+	 * doesn't make sense. Rely on vruntime for fairness.
+	 */
+	delay = max_t(u64, delay, 10000LL);
+	hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay),
+		      HRTIMER_MODE_REL_PINNED_HARD);
+}
+#endif /* CONFIG_SMP */
+
+static void hrtick_rq_init(struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	rq_csd_init(rq, &rq->hrtick_csd, __hrtick_start);
+#endif
+
+	hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
+	rq->hrtick_timer.function = hrtick;
+}
+#else	/* CONFIG_SCHED_HRTICK */
+static inline int hrtick_enabled(struct rq *rq)
+{
+	return 0;
+}
+
+static inline void hrtick_clear(struct rq *rq)
+{
+}
+
+static inline void hrtick_rq_init(struct rq *rq)
+{
+}
+#endif	/* CONFIG_SCHED_HRTICK */
+
+static inline int normal_prio(struct task_struct *p)
+{
+	if (task_has_rt_policy(p))
+		return MAX_RT_PRIO - 1 - p->rt_priority;
+
+	return p->static_prio + MAX_PRIORITY_ADJ;
+}
+
+/*
+ * Calculate the current priority, i.e. the priority
+ * taken into account by the scheduler. This value might
+ * be boosted by RT tasks as it will be RT if the task got
+ * RT-boosted. If not then it returns p->normal_prio.
+ */
+static int effective_prio(struct task_struct *p)
+{
+	p->normal_prio = normal_prio(p);
+	/*
+	 * If we are RT tasks or we were boosted to RT priority,
+	 * keep the priority unchanged. Otherwise, update priority
+	 * to the normal priority:
+	 */
+	if (!rt_prio(p->prio))
+		return p->normal_prio;
+	return p->prio;
+}
+
+/*
+ * activate_task - move a task to the runqueue.
+ *
+ * Context: rq->lock
+ */
+static void activate_task(struct task_struct *p, struct rq *rq)
+{
+	enqueue_task(p, rq, ENQUEUE_WAKEUP);
+	p->on_rq = TASK_ON_RQ_QUEUED;
+	cpufreq_update_util(rq, 0);
+}
+
+/*
+ * deactivate_task - remove a task from the runqueue.
+ *
+ * Context: rq->lock
+ */
+static inline void deactivate_task(struct task_struct *p, struct rq *rq)
+{
+	dequeue_task(p, rq, DEQUEUE_SLEEP);
+	p->on_rq = 0;
+	cpufreq_update_util(rq, 0);
+}
+
+static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * After ->cpu is set up to a new value, task_access_lock(p, ...) can be
+	 * successfully executed on another CPU. We must ensure that updates of
+	 * per-task data have been completed by this moment.
+	 */
+	smp_wmb();
+
+#ifdef CONFIG_THREAD_INFO_IN_TASK
+	WRITE_ONCE(p->cpu, cpu);
+#else
+	WRITE_ONCE(task_thread_info(p)->cpu, cpu);
+#endif
+#endif
+}
+
+#ifdef CONFIG_SMP
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
+{
+#ifdef CONFIG_SCHED_DEBUG
+	/*
+	 * We should never call set_task_cpu() on a blocked task,
+	 * ttwu() will sort out the placement.
+	 */
+	WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
+		     !p->on_rq);
+#ifdef CONFIG_LOCKDEP
+	/*
+	 * The caller should hold either p->pi_lock or rq->lock, when changing
+	 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
+	 *
+	 * sched_move_task() holds both and thus holding either pins the cgroup,
+	 * see task_group().
+	 */
+	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
+				      lockdep_is_held(&task_rq(p)->lock)));
+#endif
+	/*
+	 * Clearly, migrating tasks to offline CPUs is a fairly daft thing.
+	 */
+	WARN_ON_ONCE(!cpu_online(new_cpu));
+#endif
+	if (task_cpu(p) == new_cpu)
+		return;
+	trace_sched_migrate_task(p, new_cpu);
+	rseq_migrate(p);
+	perf_event_task_migrate(p);
+
+	__set_task_cpu(p, new_cpu);
+}
+
+static inline bool is_per_cpu_kthread(struct task_struct *p)
+{
+	return ((p->flags & PF_KTHREAD) && (1 == p->nr_cpus_allowed));
+}
+
+/*
+ * Per-CPU kthreads are allowed to run on !active && online CPUs, see
+ * __set_cpus_allowed_ptr() and select_fallback_rq().
+ */
+static inline bool is_cpu_allowed(struct task_struct *p, int cpu)
+{
+	if (!cpumask_test_cpu(cpu, p->cpus_ptr))
+		return false;
+
+	if (is_per_cpu_kthread(p))
+		return cpu_online(cpu);
+
+	return cpu_active(cpu);
+}
+
+/*
+ * This is how migration works:
+ *
+ * 1) we invoke migration_cpu_stop() on the target CPU using
+ *    stop_one_cpu().
+ * 2) stopper starts to run (implicitly forcing the migrated thread
+ *    off the CPU)
+ * 3) it checks whether the migrated task is still in the wrong runqueue.
+ * 4) if it's in the wrong runqueue then the migration thread removes
+ *    it and puts it into the right queue.
+ * 5) stopper completes and stop_one_cpu() returns and the migration
+ *    is done.
+ */
+
+/*
+ * move_queued_task - move a queued task to new rq.
+ *
+ * Returns (locked) new rq. Old rq's lock is released.
+ */
+static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int
+				   new_cpu)
+{
+	lockdep_assert_held(&rq->lock);
+
+	WRITE_ONCE(p->on_rq, TASK_ON_RQ_MIGRATING);
+	dequeue_task(p, rq, 0);
+	set_task_cpu(p, new_cpu);
+	raw_spin_unlock(&rq->lock);
+
+	rq = cpu_rq(new_cpu);
+
+	raw_spin_lock(&rq->lock);
+	BUG_ON(task_cpu(p) != new_cpu);
+	enqueue_task(p, rq, 0);
+	p->on_rq = TASK_ON_RQ_QUEUED;
+	check_preempt_curr(rq);
+
+	return rq;
+}
+
+struct migration_arg {
+	struct task_struct *task;
+	int dest_cpu;
+};
+
+/*
+ * Move (not current) task off this CPU, onto the destination CPU. We're doing
+ * this because either it can't run here any more (set_cpus_allowed()
+ * away from this CPU, or CPU going down), or because we're
+ * attempting to rebalance this task on exec (sched_exec).
+ *
+ * So we race with normal scheduler movements, but that's OK, as long
+ * as the task is no longer on this CPU.
+ */
+static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int
+				 dest_cpu)
+{
+	/* Affinity changed (again). */
+	if (!is_cpu_allowed(p, dest_cpu))
+		return rq;
+
+	update_rq_clock(rq);
+	return move_queued_task(rq, p, dest_cpu);
+}
+
+/*
+ * migration_cpu_stop - this will be executed by a highprio stopper thread
+ * and performs thread migration by bumping thread off CPU then
+ * 'pushing' onto another runqueue.
+ */
+static int migration_cpu_stop(void *data)
+{
+	struct migration_arg *arg = data;
+	struct task_struct *p = arg->task;
+	struct rq *rq = this_rq();
+
+	/*
+	 * The original target CPU might have gone down and we might
+	 * be on another CPU but it doesn't matter.
+	 */
+	local_irq_disable();
+	/*
+	 * We need to explicitly wake pending tasks before running
+	 * __migrate_task() such that we will not miss enforcing cpus_ptr
+	 * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test.
+	 */
+	flush_smp_call_function_from_idle();
+
+	raw_spin_lock(&p->pi_lock);
+	raw_spin_lock(&rq->lock);
+	/*
+	 * If task_rq(p) != rq, it cannot be migrated here, because we're
+	 * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because
+	 * we're holding p->pi_lock.
+	 */
+	if (task_rq(p) == rq && task_on_rq_queued(p))
+		rq = __migrate_task(rq, p, arg->dest_cpu);
+	raw_spin_unlock(&rq->lock);
+	raw_spin_unlock(&p->pi_lock);
+
+	local_irq_enable();
+	return 0;
+}
+
+static inline void
+set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask)
+{
+	cpumask_copy(&p->cpus_mask, new_mask);
+	p->nr_cpus_allowed = cpumask_weight(new_mask);
+}
+
+void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
+{
+	set_cpus_allowed_common(p, new_mask);
+}
+#endif
+
+/**
+ * task_curr - is this task currently executing on a CPU?
+ * @p: the task in question.
+ *
+ * Return: 1 if the task is currently executing. 0 otherwise.
+ */
+inline int task_curr(const struct task_struct *p)
+{
+	return cpu_curr(task_cpu(p)) == p;
+}
+
+#ifdef CONFIG_SMP
+/*
+ * wait_task_inactive - wait for a thread to unschedule.
+ *
+ * If @match_state is nonzero, it's the @p->state value just checked and
+ * not expected to change.  If it changes, i.e. @p might have woken up,
+ * then return zero.  When we succeed in waiting for @p to be off its CPU,
+ * we return a positive number (its total switch count).  If a second call
+ * a short while later returns the same number, the caller can be sure that
+ * @p has remained unscheduled the whole time.
+ *
+ * The caller must ensure that the task *will* unschedule sometime soon,
+ * else this function might spin for a *long* time. This function can't
+ * be called with interrupts off, or it may introduce deadlock with
+ * smp_call_function() if an IPI is sent by the same process we are
+ * waiting to become inactive.
+ */
+unsigned long wait_task_inactive(struct task_struct *p, long match_state)
+{
+	unsigned long flags;
+	bool running, on_rq;
+	unsigned long ncsw;
+	struct rq *rq;
+	raw_spinlock_t *lock;
+
+	for (;;) {
+		rq = task_rq(p);
+
+		/*
+		 * If the task is actively running on another CPU
+		 * still, just relax and busy-wait without holding
+		 * any locks.
+		 *
+		 * NOTE! Since we don't hold any locks, it's not
+		 * even sure that "rq" stays as the right runqueue!
+		 * But we don't care, since this will return false
+		 * if the runqueue has changed and p is actually now
+		 * running somewhere else!
+		 */
+		while (task_running(p) && p == rq->curr) {
+			if (match_state && unlikely(p->state != match_state))
+				return 0;
+			cpu_relax();
+		}
+
+		/*
+		 * Ok, time to look more closely! We need the rq
+		 * lock now, to be *sure*. If we're wrong, we'll
+		 * just go back and repeat.
+		 */
+		task_access_lock_irqsave(p, &lock, &flags);
+		trace_sched_wait_task(p);
+		running = task_running(p);
+		on_rq = p->on_rq;
+		ncsw = 0;
+		if (!match_state || p->state == match_state)
+			ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
+		task_access_unlock_irqrestore(p, lock, &flags);
+
+		/*
+		 * If it changed from the expected state, bail out now.
+		 */
+		if (unlikely(!ncsw))
+			break;
+
+		/*
+		 * Was it really running after all now that we
+		 * checked with the proper locks actually held?
+		 *
+		 * Oops. Go back and try again..
+		 */
+		if (unlikely(running)) {
+			cpu_relax();
+			continue;
+		}
+
+		/*
+		 * It's not enough that it's not actively running,
+		 * it must be off the runqueue _entirely_, and not
+		 * preempted!
+		 *
+		 * So if it was still runnable (but just not actively
+		 * running right now), it's preempted, and we should
+		 * yield - it could be a while.
+		 */
+		if (unlikely(on_rq)) {
+			ktime_t to = NSEC_PER_SEC / HZ;
+
+			set_current_state(TASK_UNINTERRUPTIBLE);
+			schedule_hrtimeout(&to, HRTIMER_MODE_REL);
+			continue;
+		}
+
+		/*
+		 * Ahh, all good. It wasn't running, and it wasn't
+		 * runnable, which means that it will never become
+		 * running in the future either. We're all done!
+		 */
+		break;
+	}
+
+	return ncsw;
+}
+
+/***
+ * kick_process - kick a running thread to enter/exit the kernel
+ * @p: the to-be-kicked thread
+ *
+ * Cause a process which is running on another CPU to enter
+ * kernel-mode, without any delay. (to get signals handled.)
+ *
+ * NOTE: this function doesn't have to take the runqueue lock,
+ * because all it wants to ensure is that the remote task enters
+ * the kernel. If the IPI races and the task has been migrated
+ * to another CPU then no harm is done and the purpose has been
+ * achieved as well.
+ */
+void kick_process(struct task_struct *p)
+{
+	int cpu;
+
+	preempt_disable();
+	cpu = task_cpu(p);
+	if ((cpu != smp_processor_id()) && task_curr(p))
+		smp_send_reschedule(cpu);
+	preempt_enable();
+}
+EXPORT_SYMBOL_GPL(kick_process);
+
+/*
+ * ->cpus_ptr is protected by both rq->lock and p->pi_lock
+ *
+ * A few notes on cpu_active vs cpu_online:
+ *
+ *  - cpu_active must be a subset of cpu_online
+ *
+ *  - on CPU-up we allow per-CPU kthreads on the online && !active CPU,
+ *    see __set_cpus_allowed_ptr(). At this point the newly online
+ *    CPU isn't yet part of the sched domains, and balancing will not
+ *    see it.
+ *
+ *  - on cpu-down we clear cpu_active() to mask the sched domains and
+ *    avoid the load balancer to place new tasks on the to be removed
+ *    CPU. Existing tasks will remain running there and will be taken
+ *    off.
+ *
+ * This means that fallback selection must not select !active CPUs.
+ * And can assume that any active CPU must be online. Conversely
+ * select_task_rq() below may allow selection of !active CPUs in order
+ * to satisfy the above rules.
+ */
+static int select_fallback_rq(int cpu, struct task_struct *p)
+{
+	int nid = cpu_to_node(cpu);
+	const struct cpumask *nodemask = NULL;
+	enum { cpuset, possible, fail } state = cpuset;
+	int dest_cpu;
+
+	/*
+	 * If the node that the CPU is on has been offlined, cpu_to_node()
+	 * will return -1. There is no CPU on the node, and we should
+	 * select the CPU on the other node.
+	 */
+	if (nid != -1) {
+		nodemask = cpumask_of_node(nid);
+
+		/* Look for allowed, online CPU in same node. */
+		for_each_cpu(dest_cpu, nodemask) {
+			if (!cpu_active(dest_cpu))
+				continue;
+			if (cpumask_test_cpu(dest_cpu, p->cpus_ptr))
+				return dest_cpu;
+		}
+	}
+
+	for (;;) {
+		/* Any allowed, online CPU? */
+		for_each_cpu(dest_cpu, p->cpus_ptr) {
+			if (!is_cpu_allowed(p, dest_cpu))
+				continue;
+			goto out;
+		}
+
+		/* No more Mr. Nice Guy. */
+		switch (state) {
+		case cpuset:
+			if (IS_ENABLED(CONFIG_CPUSETS)) {
+				cpuset_cpus_allowed_fallback(p);
+				state = possible;
+				break;
+			}
+			fallthrough;
+		case possible:
+			do_set_cpus_allowed(p, cpu_possible_mask);
+			state = fail;
+			break;
+
+		case fail:
+			BUG();
+			break;
+		}
+	}
+
+out:
+	if (state != cpuset) {
+		/*
+		 * Don't tell them about moving exiting tasks or
+		 * kernel threads (both mm NULL), since they never
+		 * leave kernel.
+		 */
+		if (p->mm && printk_ratelimit()) {
+			printk_deferred("process %d (%s) no longer affine to cpu%d\n",
+					task_pid_nr(p), p->comm, cpu);
+		}
+	}
+
+	return dest_cpu;
+}
+
+static inline int select_task_rq(struct task_struct *p, struct rq *rq)
+{
+	cpumask_t chk_mask, tmp;
+
+	if (unlikely(!cpumask_and(&chk_mask, p->cpus_ptr, cpu_online_mask)))
+		return select_fallback_rq(task_cpu(p), p);
+
+	if (
+#ifdef CONFIG_SCHED_SMT
+	    cpumask_and(&tmp, &chk_mask, &sched_sg_idle_mask) ||
+#endif
+	    cpumask_and(&tmp, &chk_mask, &sched_rq_watermark[IDLE_WM]) ||
+	    cpumask_and(&tmp, &chk_mask,
+			&sched_rq_watermark[task_sched_prio(p, rq) + 1]))
+		return best_mask_cpu(task_cpu(p), &tmp);
+
+	return best_mask_cpu(task_cpu(p), &chk_mask);
+}
+
+void sched_set_stop_task(int cpu, struct task_struct *stop)
+{
+	struct sched_param stop_param = { .sched_priority = STOP_PRIO };
+	struct sched_param start_param = { .sched_priority = 0 };
+	struct task_struct *old_stop = cpu_rq(cpu)->stop;
+
+	if (stop) {
+		/*
+		 * Make it appear like a SCHED_FIFO task, its something
+		 * userspace knows about and won't get confused about.
+		 *
+		 * Also, it will make PI more or less work without too
+		 * much confusion -- but then, stop work should not
+		 * rely on PI working anyway.
+		 */
+		sched_setscheduler_nocheck(stop, SCHED_FIFO, &stop_param);
+	}
+
+	cpu_rq(cpu)->stop = stop;
+
+	if (old_stop) {
+		/*
+		 * Reset it back to a normal scheduling policy so that
+		 * it can die in pieces.
+		 */
+		sched_setscheduler_nocheck(old_stop, SCHED_NORMAL, &start_param);
+	}
+}
+
+/*
+ * Change a given task's CPU affinity. Migrate the thread to a
+ * proper CPU and schedule it away if the CPU it's executing on
+ * is removed from the allowed bitmask.
+ *
+ * NOTE: the caller must have a valid reference to the task, the
+ * task must not exit() & deallocate itself prematurely. The
+ * call is not atomic; no spinlocks may be held.
+ */
+static int __set_cpus_allowed_ptr(struct task_struct *p,
+				  const struct cpumask *new_mask, bool check)
+{
+	const struct cpumask *cpu_valid_mask = cpu_active_mask;
+	int dest_cpu;
+	unsigned long flags;
+	struct rq *rq;
+	raw_spinlock_t *lock;
+	int ret = 0;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	rq = __task_access_lock(p, &lock);
+
+	if (p->flags & PF_KTHREAD) {
+		/*
+		 * Kernel threads are allowed on online && !active CPUs
+		 */
+		cpu_valid_mask = cpu_online_mask;
+	}
+
+	/*
+	 * Must re-check here, to close a race against __kthread_bind(),
+	 * sched_setaffinity() is not guaranteed to observe the flag.
+	 */
+	if (check && (p->flags & PF_NO_SETAFFINITY)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (cpumask_equal(&p->cpus_mask, new_mask))
+		goto out;
+
+	dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask);
+	if (dest_cpu >= nr_cpu_ids) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	do_set_cpus_allowed(p, new_mask);
+
+	if (p->flags & PF_KTHREAD) {
+		/*
+		 * For kernel threads that do indeed end up on online &&
+		 * !active we want to ensure they are strict per-CPU threads.
+		 */
+		WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) &&
+			!cpumask_intersects(new_mask, cpu_active_mask) &&
+			p->nr_cpus_allowed != 1);
+	}
+
+	/* Can the task run on the task's current CPU? If so, we're done */
+	if (cpumask_test_cpu(task_cpu(p), new_mask))
+		goto out;
+
+	if (task_running(p) || p->state == TASK_WAKING) {
+		struct migration_arg arg = { p, dest_cpu };
+
+		/* Need help from migration thread: drop lock and wait. */
+		__task_access_unlock(p, lock);
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg);
+		return 0;
+	}
+	if (task_on_rq_queued(p)) {
+		/*
+		 * OK, since we're going to drop the lock immediately
+		 * afterwards anyway.
+		 */
+		update_rq_clock(rq);
+		rq = move_queued_task(rq, p, dest_cpu);
+		lock = &rq->lock;
+	}
+
+out:
+	__task_access_unlock(p, lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	return ret;
+}
+
+int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
+{
+	return __set_cpus_allowed_ptr(p, new_mask, false);
+}
+EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
+
+#else /* CONFIG_SMP */
+
+static inline int select_task_rq(struct task_struct *p, struct rq *rq)
+{
+	return 0;
+}
+
+static inline int
+__set_cpus_allowed_ptr(struct task_struct *p,
+		       const struct cpumask *new_mask, bool check)
+{
+	return set_cpus_allowed_ptr(p, new_mask);
+}
+
+#endif /* CONFIG_SMP */
+
+static void
+ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq;
+
+	if (!schedstat_enabled())
+		return;
+
+	rq= this_rq();
+
+#ifdef CONFIG_SMP
+	if (cpu == rq->cpu)
+		__schedstat_inc(rq->ttwu_local);
+	else {
+		/** Alt schedule FW ToDo:
+		 * How to do ttwu_wake_remote
+		 */
+	}
+#endif /* CONFIG_SMP */
+
+	__schedstat_inc(rq->ttwu_count);
+}
+
+/*
+ * Mark the task runnable and perform wakeup-preemption.
+ */
+static inline void
+ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags)
+{
+	check_preempt_curr(rq);
+	p->state = TASK_RUNNING;
+	trace_sched_wakeup(p);
+}
+
+static inline void
+ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags)
+{
+	if (p->sched_contributes_to_load)
+		rq->nr_uninterruptible--;
+
+	activate_task(p, rq);
+	ttwu_do_wakeup(rq, p, 0);
+}
+
+/*
+ * Consider @p being inside a wait loop:
+ *
+ *   for (;;) {
+ *      set_current_state(TASK_UNINTERRUPTIBLE);
+ *
+ *      if (CONDITION)
+ *         break;
+ *
+ *      schedule();
+ *   }
+ *   __set_current_state(TASK_RUNNING);
+ *
+ * between set_current_state() and schedule(). In this case @p is still
+ * runnable, so all that needs doing is change p->state back to TASK_RUNNING in
+ * an atomic manner.
+ *
+ * By taking task_rq(p)->lock we serialize against schedule(), if @p->on_rq
+ * then schedule() must still happen and p->state can be changed to
+ * TASK_RUNNING. Otherwise we lost the race, schedule() has happened, and we
+ * need to do a full wakeup with enqueue.
+ *
+ * Returns: %true when the wakeup is done,
+ *          %false otherwise.
+ */
+static int ttwu_runnable(struct task_struct *p, int wake_flags)
+{
+	struct rq *rq;
+	raw_spinlock_t *lock;
+	int ret = 0;
+
+	rq = __task_access_lock(p, &lock);
+	if (task_on_rq_queued(p)) {
+		/* check_preempt_curr() may use rq clock */
+		update_rq_clock(rq);
+		ttwu_do_wakeup(rq, p, wake_flags);
+		ret = 1;
+	}
+	__task_access_unlock(p, lock);
+
+	return ret;
+}
+
+#ifdef CONFIG_SMP
+void sched_ttwu_pending(void *arg)
+{
+	struct llist_node *llist = arg;
+	struct rq *rq = this_rq();
+	struct task_struct *p, *t;
+	struct rq_flags rf;
+
+	if (!llist)
+		return;
+
+	/*
+	 * rq::ttwu_pending racy indication of out-standing wakeups.
+	 * Races such that false-negatives are possible, since they
+	 * are shorter lived that false-positives would be.
+	 */
+	WRITE_ONCE(rq->ttwu_pending, 0);
+
+	rq_lock_irqsave(rq, &rf);
+	update_rq_clock(rq);
+
+	llist_for_each_entry_safe(p, t, llist, wake_entry.llist) {
+		if (WARN_ON_ONCE(p->on_cpu))
+			smp_cond_load_acquire(&p->on_cpu, !VAL);
+
+		if (WARN_ON_ONCE(task_cpu(p) != cpu_of(rq)))
+			set_task_cpu(p, cpu_of(rq));
+
+		ttwu_do_activate(rq, p, p->sched_remote_wakeup ? WF_MIGRATED : 0);
+	}
+
+	rq_unlock_irqrestore(rq, &rf);
+}
+
+void send_call_function_single_ipi(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (!set_nr_if_polling(rq->idle))
+		arch_send_call_function_single_ipi(cpu);
+	else
+		trace_sched_wake_idle_without_ipi(cpu);
+}
+
+/*
+ * Queue a task on the target CPUs wake_list and wake the CPU via IPI if
+ * necessary. The wakee CPU on receipt of the IPI will queue the task
+ * via sched_ttwu_wakeup() for activation so the wakee incurs the cost
+ * of the wakeup instead of the waker.
+ */
+static void __ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED);
+
+	WRITE_ONCE(rq->ttwu_pending, 1);
+	__smp_call_single_queue(cpu, &p->wake_entry.llist);
+}
+
+static inline bool ttwu_queue_cond(int cpu, int wake_flags)
+{
+	/*
+	 * If the CPU does not share cache, then queue the task on the
+	 * remote rqs wakelist to avoid accessing remote data.
+	 */
+	if (!cpus_share_cache(smp_processor_id(), cpu))
+		return true;
+
+	/*
+	 * If the task is descheduling and the only running task on the
+	 * CPU then use the wakelist to offload the task activation to
+	 * the soon-to-be-idle CPU as the current CPU is likely busy.
+	 * nr_running is checked to avoid unnecessary task stacking.
+	 */
+	if ((wake_flags & WF_ON_CPU) && cpu_rq(cpu)->nr_running <= 1)
+		return true;
+
+	return false;
+}
+
+static bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	if (__is_defined(ALT_SCHED_TTWU_QUEUE) && ttwu_queue_cond(cpu, wake_flags)) {
+		if (WARN_ON_ONCE(cpu == smp_processor_id()))
+			return false;
+
+		sched_clock_cpu(cpu); /* Sync clocks across CPUs */
+		__ttwu_queue_wakelist(p, cpu, wake_flags);
+		return true;
+	}
+
+	return false;
+}
+
+void wake_up_if_idle(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	rcu_read_lock();
+
+	if (!is_idle_task(rcu_dereference(rq->curr)))
+		goto out;
+
+	if (set_nr_if_polling(rq->idle)) {
+		trace_sched_wake_idle_without_ipi(cpu);
+	} else {
+		raw_spin_lock_irqsave(&rq->lock, flags);
+		if (is_idle_task(rq->curr))
+			smp_send_reschedule(cpu);
+		/* Else CPU is not idle, do nothing here */
+		raw_spin_unlock_irqrestore(&rq->lock, flags);
+	}
+
+out:
+	rcu_read_unlock();
+}
+
+bool cpus_share_cache(int this_cpu, int that_cpu)
+{
+	return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu);
+}
+#else /* !CONFIG_SMP */
+
+static inline bool ttwu_queue_wakelist(struct task_struct *p, int cpu, int wake_flags)
+{
+	return false;
+}
+
+#endif /* CONFIG_SMP */
+
+static inline void ttwu_queue(struct task_struct *p, int cpu, int wake_flags)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (ttwu_queue_wakelist(p, cpu, wake_flags))
+		return;
+
+	raw_spin_lock(&rq->lock);
+	update_rq_clock(rq);
+	ttwu_do_activate(rq, p, wake_flags);
+	raw_spin_unlock(&rq->lock);
+}
+
+/*
+ * Notes on Program-Order guarantees on SMP systems.
+ *
+ *  MIGRATION
+ *
+ * The basic program-order guarantee on SMP systems is that when a task [t]
+ * migrates, all its activity on its old CPU [c0] happens-before any subsequent
+ * execution on its new CPU [c1].
+ *
+ * For migration (of runnable tasks) this is provided by the following means:
+ *
+ *  A) UNLOCK of the rq(c0)->lock scheduling out task t
+ *  B) migration for t is required to synchronize *both* rq(c0)->lock and
+ *     rq(c1)->lock (if not at the same time, then in that order).
+ *  C) LOCK of the rq(c1)->lock scheduling in task
+ *
+ * Transitivity guarantees that B happens after A and C after B.
+ * Note: we only require RCpc transitivity.
+ * Note: the CPU doing B need not be c0 or c1
+ *
+ * Example:
+ *
+ *   CPU0            CPU1            CPU2
+ *
+ *   LOCK rq(0)->lock
+ *   sched-out X
+ *   sched-in Y
+ *   UNLOCK rq(0)->lock
+ *
+ *                                   LOCK rq(0)->lock // orders against CPU0
+ *                                   dequeue X
+ *                                   UNLOCK rq(0)->lock
+ *
+ *                                   LOCK rq(1)->lock
+ *                                   enqueue X
+ *                                   UNLOCK rq(1)->lock
+ *
+ *                   LOCK rq(1)->lock // orders against CPU2
+ *                   sched-out Z
+ *                   sched-in X
+ *                   UNLOCK rq(1)->lock
+ *
+ *
+ *  BLOCKING -- aka. SLEEP + WAKEUP
+ *
+ * For blocking we (obviously) need to provide the same guarantee as for
+ * migration. However the means are completely different as there is no lock
+ * chain to provide order. Instead we do:
+ *
+ *   1) smp_store_release(X->on_cpu, 0)   -- finish_task()
+ *   2) smp_cond_load_acquire(!X->on_cpu) -- try_to_wake_up()
+ *
+ * Example:
+ *
+ *   CPU0 (schedule)  CPU1 (try_to_wake_up) CPU2 (schedule)
+ *
+ *   LOCK rq(0)->lock LOCK X->pi_lock
+ *   dequeue X
+ *   sched-out X
+ *   smp_store_release(X->on_cpu, 0);
+ *
+ *                    smp_cond_load_acquire(&X->on_cpu, !VAL);
+ *                    X->state = WAKING
+ *                    set_task_cpu(X,2)
+ *
+ *                    LOCK rq(2)->lock
+ *                    enqueue X
+ *                    X->state = RUNNING
+ *                    UNLOCK rq(2)->lock
+ *
+ *                                          LOCK rq(2)->lock // orders against CPU1
+ *                                          sched-out Z
+ *                                          sched-in X
+ *                                          UNLOCK rq(2)->lock
+ *
+ *                    UNLOCK X->pi_lock
+ *   UNLOCK rq(0)->lock
+ *
+ *
+ * However; for wakeups there is a second guarantee we must provide, namely we
+ * must observe the state that lead to our wakeup. That is, not only must our
+ * task observe its own prior state, it must also observe the stores prior to
+ * its wakeup.
+ *
+ * This means that any means of doing remote wakeups must order the CPU doing
+ * the wakeup against the CPU the task is going to end up running on. This,
+ * however, is already required for the regular Program-Order guarantee above,
+ * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire).
+ *
+ */
+
+/**
+ * try_to_wake_up - wake up a thread
+ * @p: the thread to be awakened
+ * @state: the mask of task states that can be woken
+ * @wake_flags: wake modifier flags (WF_*)
+ *
+ * Conceptually does:
+ *
+ *   If (@state & @p->state) @p->state = TASK_RUNNING.
+ *
+ * If the task was not queued/runnable, also place it back on a runqueue.
+ *
+ * This function is atomic against schedule() which would dequeue the task.
+ *
+ * It issues a full memory barrier before accessing @p->state, see the comment
+ * with set_current_state().
+ *
+ * Uses p->pi_lock to serialize against concurrent wake-ups.
+ *
+ * Relies on p->pi_lock stabilizing:
+ *  - p->sched_class
+ *  - p->cpus_ptr
+ *  - p->sched_task_group
+ * in order to do migration, see its use of select_task_rq()/set_task_cpu().
+ *
+ * Tries really hard to only take one task_rq(p)->lock for performance.
+ * Takes rq->lock in:
+ *  - ttwu_runnable()    -- old rq, unavoidable, see comment there;
+ *  - ttwu_queue()       -- new rq, for enqueue of the task;
+ *  - psi_ttwu_dequeue() -- much sadness :-( accounting will kill us.
+ *
+ * As a consequence we race really badly with just about everything. See the
+ * many memory barriers and their comments for details.
+ *
+ * Return: %true if @p->state changes (an actual wakeup was done),
+ *	   %false otherwise.
+ */
+static int try_to_wake_up(struct task_struct *p, unsigned int state,
+			  int wake_flags)
+{
+	unsigned long flags;
+	int cpu, success = 0;
+
+	preempt_disable();
+	if (p == current) {
+		/*
+		 * We're waking current, this means 'p->on_rq' and 'task_cpu(p)
+		 * == smp_processor_id()'. Together this means we can special
+		 * case the whole 'p->on_rq && ttwu_runnable()' case below
+		 * without taking any locks.
+		 *
+		 * In particular:
+		 *  - we rely on Program-Order guarantees for all the ordering,
+		 *  - we're serialized against set_special_state() by virtue of
+		 *    it disabling IRQs (this allows not taking ->pi_lock).
+		 */
+		if (!(p->state & state))
+			goto out;
+
+		success = 1;
+		trace_sched_waking(p);
+		p->state = TASK_RUNNING;
+		trace_sched_wakeup(p);
+		goto out;
+	}
+
+	/*
+	 * If we are going to wake up a thread waiting for CONDITION we
+	 * need to ensure that CONDITION=1 done by the caller can not be
+	 * reordered with p->state check below. This pairs with smp_store_mb()
+	 * in set_current_state() that the waiting thread does.
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	smp_mb__after_spinlock();
+	if (!(p->state & state))
+		goto unlock;
+
+	trace_sched_waking(p);
+
+	/* We're going to change ->state: */
+	success = 1;
+
+	/*
+	 * Ensure we load p->on_rq _after_ p->state, otherwise it would
+	 * be possible to, falsely, observe p->on_rq == 0 and get stuck
+	 * in smp_cond_load_acquire() below.
+	 *
+	 * sched_ttwu_pending()			try_to_wake_up()
+	 *   STORE p->on_rq = 1			  LOAD p->state
+	 *   UNLOCK rq->lock
+	 *
+	 * __schedule() (switch to task 'p')
+	 *   LOCK rq->lock			  smp_rmb();
+	 *   smp_mb__after_spinlock();
+	 *   UNLOCK rq->lock
+	 *
+	 * [task p]
+	 *   STORE p->state = UNINTERRUPTIBLE	  LOAD p->on_rq
+	 *
+	 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
+	 * __schedule().  See the comment for smp_mb__after_spinlock().
+	 *
+	 * A similar smb_rmb() lives in try_invoke_on_locked_down_task().
+	 */
+	smp_rmb();
+	if (READ_ONCE(p->on_rq) && ttwu_runnable(p, wake_flags))
+		goto unlock;
+
+	if (p->in_iowait) {
+		delayacct_blkio_end(p);
+		atomic_dec(&task_rq(p)->nr_iowait);
+	}
+
+#ifdef CONFIG_SMP
+	/*
+	 * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be
+	 * possible to, falsely, observe p->on_cpu == 0.
+	 *
+	 * One must be running (->on_cpu == 1) in order to remove oneself
+	 * from the runqueue.
+	 *
+	 * __schedule() (switch to task 'p')	try_to_wake_up()
+	 *   STORE p->on_cpu = 1		  LOAD p->on_rq
+	 *   UNLOCK rq->lock
+	 *
+	 * __schedule() (put 'p' to sleep)
+	 *   LOCK rq->lock			  smp_rmb();
+	 *   smp_mb__after_spinlock();
+	 *   STORE p->on_rq = 0			  LOAD p->on_cpu
+	 *
+	 * Pairs with the LOCK+smp_mb__after_spinlock() on rq->lock in
+	 * __schedule().  See the comment for smp_mb__after_spinlock().
+	 *
+	 * Form a control-dep-acquire with p->on_rq == 0 above, to ensure
+	 * schedule()'s deactivate_task() has 'happened' and p will no longer
+	 * care about it's own p->state. See the comment in __schedule().
+	 */
+	smp_acquire__after_ctrl_dep();
+
+	/*
+	 * We're doing the wakeup (@success == 1), they did a dequeue (p->on_rq
+	 * == 0), which means we need to do an enqueue, change p->state to
+	 * TASK_WAKING such that we can unlock p->pi_lock before doing the
+	 * enqueue, such as ttwu_queue_wakelist().
+	 */
+	p->state = TASK_WAKING;
+
+	/*
+	 * If the owning (remote) CPU is still in the middle of schedule() with
+	 * this task as prev, considering queueing p on the remote CPUs wake_list
+	 * which potentially sends an IPI instead of spinning on p->on_cpu to
+	 * let the waker make forward progress. This is safe because IRQs are
+	 * disabled and the IPI will deliver after on_cpu is cleared.
+	 *
+	 * Ensure we load task_cpu(p) after p->on_cpu:
+	 *
+	 * set_task_cpu(p, cpu);
+	 *   STORE p->cpu = @cpu
+	 * __schedule() (switch to task 'p')
+	 *   LOCK rq->lock
+	 *   smp_mb__after_spin_lock()          smp_cond_load_acquire(&p->on_cpu)
+	 *   STORE p->on_cpu = 1                LOAD p->cpu
+	 *
+	 * to ensure we observe the correct CPU on which the task is currently
+	 * scheduling.
+	 */
+	if (smp_load_acquire(&p->on_cpu) &&
+	    ttwu_queue_wakelist(p, task_cpu(p), wake_flags | WF_ON_CPU))
+		goto unlock;
+
+	/*
+	 * If the owning (remote) CPU is still in the middle of schedule() with
+	 * this task as prev, wait until its done referencing the task.
+	 *
+	 * Pairs with the smp_store_release() in finish_task().
+	 *
+	 * This ensures that tasks getting woken will be fully ordered against
+	 * their previous state and preserve Program Order.
+	 */
+	smp_cond_load_acquire(&p->on_cpu, !VAL);
+
+	sched_task_ttwu(p);
+
+	cpu = select_task_rq(p, this_rq());
+
+	if (cpu != task_cpu(p)) {
+		wake_flags |= WF_MIGRATED;
+		psi_ttwu_dequeue(p);
+		set_task_cpu(p, cpu);
+	}
+#else
+	cpu = task_cpu(p);
+#endif /* CONFIG_SMP */
+
+	ttwu_queue(p, cpu, wake_flags);
+unlock:
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+out:
+	if (success)
+		ttwu_stat(p, task_cpu(p), wake_flags);
+	preempt_enable();
+
+	return success;
+}
+
+/**
+ * try_invoke_on_locked_down_task - Invoke a function on task in fixed state
+ * @p: Process for which the function is to be invoked.
+ * @func: Function to invoke.
+ * @arg: Argument to function.
+ *
+ * If the specified task can be quickly locked into a definite state
+ * (either sleeping or on a given runqueue), arrange to keep it in that
+ * state while invoking @func(@arg).  This function can use ->on_rq and
+ * task_curr() to work out what the state is, if required.  Given that
+ * @func can be invoked with a runqueue lock held, it had better be quite
+ * lightweight.
+ *
+ * Returns:
+ *	@false if the task slipped out from under the locks.
+ *	@true if the task was locked onto a runqueue or is sleeping.
+ *		However, @func can override this by returning @false.
+ */
+bool try_invoke_on_locked_down_task(struct task_struct *p, bool (*func)(struct task_struct *t, void *arg), void *arg)
+{
+	bool ret = false;
+	struct rq_flags rf;
+	struct rq *rq;
+
+	lockdep_assert_irqs_enabled();
+	raw_spin_lock_irq(&p->pi_lock);
+	if (p->on_rq) {
+		rq = __task_rq_lock(p, &rf);
+		if (task_rq(p) == rq)
+			ret = func(p, arg);
+		__task_rq_unlock(rq, &rf);
+	} else {
+		switch (p->state) {
+		case TASK_RUNNING:
+		case TASK_WAKING:
+			break;
+		default:
+			smp_rmb(); // See smp_rmb() comment in try_to_wake_up().
+			if (!p->on_rq)
+				ret = func(p, arg);
+		}
+	}
+	raw_spin_unlock_irq(&p->pi_lock);
+	return ret;
+}
+
+/**
+ * wake_up_process - Wake up a specific process
+ * @p: The process to be woken up.
+ *
+ * Attempt to wake up the nominated process and move it to the set of runnable
+ * processes.
+ *
+ * Return: 1 if the process was woken up, 0 if it was already running.
+ *
+ * This function executes a full memory barrier before accessing the task state.
+ */
+int wake_up_process(struct task_struct *p)
+{
+	return try_to_wake_up(p, TASK_NORMAL, 0);
+}
+EXPORT_SYMBOL(wake_up_process);
+
+int wake_up_state(struct task_struct *p, unsigned int state)
+{
+	return try_to_wake_up(p, state, 0);
+}
+
+/*
+ * Perform scheduler related setup for a newly forked process p.
+ * p is forked by current.
+ *
+ * __sched_fork() is basic setup used by init_idle() too:
+ */
+static inline void __sched_fork(unsigned long clone_flags, struct task_struct *p)
+{
+	p->on_rq			= 0;
+	p->on_cpu			= 0;
+	p->utime			= 0;
+	p->stime			= 0;
+	p->sched_time			= 0;
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+	INIT_HLIST_HEAD(&p->preempt_notifiers);
+#endif
+
+#ifdef CONFIG_COMPACTION
+	p->capture_control = NULL;
+#endif
+#ifdef CONFIG_SMP
+	p->wake_entry.u_flags = CSD_TYPE_TTWU;
+#endif
+}
+
+/*
+ * fork()/clone()-time setup:
+ */
+int sched_fork(unsigned long clone_flags, struct task_struct *p)
+{
+	unsigned long flags;
+	struct rq *rq;
+
+	__sched_fork(clone_flags, p);
+	/*
+	 * We mark the process as NEW here. This guarantees that
+	 * nobody will actually run it, and a signal or other external
+	 * event cannot wake it up and insert it on the runqueue either.
+	 */
+	p->state = TASK_NEW;
+
+	/*
+	 * Make sure we do not leak PI boosting priority to the child.
+	 */
+	p->prio = current->normal_prio;
+
+	/*
+	 * Revert to default priority/policy on fork if requested.
+	 */
+	if (unlikely(p->sched_reset_on_fork)) {
+		if (task_has_rt_policy(p)) {
+			p->policy = SCHED_NORMAL;
+			p->static_prio = NICE_TO_PRIO(0);
+			p->rt_priority = 0;
+		} else if (PRIO_TO_NICE(p->static_prio) < 0)
+			p->static_prio = NICE_TO_PRIO(0);
+
+		p->prio = p->normal_prio = normal_prio(p);
+
+		/*
+		 * We don't need the reset flag anymore after the fork. It has
+		 * fulfilled its duty:
+		 */
+		p->sched_reset_on_fork = 0;
+	}
+
+	/*
+	 * The child is not yet in the pid-hash so no cgroup attach races,
+	 * and the cgroup is pinned to this child due to cgroup_fork()
+	 * is ran before sched_fork().
+	 *
+	 * Silence PROVE_RCU.
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	/*
+	 * Share the timeslice between parent and child, thus the
+	 * total amount of pending timeslices in the system doesn't change,
+	 * resulting in more scheduling fairness.
+	 */
+	rq = this_rq();
+	raw_spin_lock(&rq->lock);
+
+	rq->curr->time_slice /= 2;
+	p->time_slice = rq->curr->time_slice;
+#ifdef CONFIG_SCHED_HRTICK
+	hrtick_start(rq, rq->curr->time_slice);
+#endif
+
+	if (p->time_slice < RESCHED_NS) {
+		p->time_slice = sched_timeslice_ns;
+		resched_curr(rq);
+	}
+	sched_task_fork(p, rq);
+	raw_spin_unlock(&rq->lock);
+
+	rseq_migrate(p);
+	/*
+	 * We're setting the CPU for the first time, we don't migrate,
+	 * so use __set_task_cpu().
+	 */
+	__set_task_cpu(p, cpu_of(rq));
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+#ifdef CONFIG_SCHED_INFO
+	if (unlikely(sched_info_on()))
+		memset(&p->sched_info, 0, sizeof(p->sched_info));
+#endif
+	init_task_preempt_count(p);
+
+	return 0;
+}
+
+void sched_post_fork(struct task_struct *p) {}
+
+#ifdef CONFIG_SCHEDSTATS
+
+DEFINE_STATIC_KEY_FALSE(sched_schedstats);
+static bool __initdata __sched_schedstats = false;
+
+static void set_schedstats(bool enabled)
+{
+	if (enabled)
+		static_branch_enable(&sched_schedstats);
+	else
+		static_branch_disable(&sched_schedstats);
+}
+
+void force_schedstat_enabled(void)
+{
+	if (!schedstat_enabled()) {
+		pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n");
+		static_branch_enable(&sched_schedstats);
+	}
+}
+
+static int __init setup_schedstats(char *str)
+{
+	int ret = 0;
+	if (!str)
+		goto out;
+
+	/*
+	 * This code is called before jump labels have been set up, so we can't
+	 * change the static branch directly just yet.  Instead set a temporary
+	 * variable so init_schedstats() can do it later.
+	 */
+	if (!strcmp(str, "enable")) {
+		__sched_schedstats = true;
+		ret = 1;
+	} else if (!strcmp(str, "disable")) {
+		__sched_schedstats = false;
+		ret = 1;
+	}
+out:
+	if (!ret)
+		pr_warn("Unable to parse schedstats=\n");
+
+	return ret;
+}
+__setup("schedstats=", setup_schedstats);
+
+static void __init init_schedstats(void)
+{
+	set_schedstats(__sched_schedstats);
+}
+
+#ifdef CONFIG_PROC_SYSCTL
+int sysctl_schedstats(struct ctl_table *table, int write,
+			 void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	struct ctl_table t;
+	int err;
+	int state = static_branch_likely(&sched_schedstats);
+
+	if (write && !capable(CAP_SYS_ADMIN))
+		return -EPERM;
+
+	t = *table;
+	t.data = &state;
+	err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos);
+	if (err < 0)
+		return err;
+	if (write)
+		set_schedstats(state);
+	return err;
+}
+#endif /* CONFIG_PROC_SYSCTL */
+#else  /* !CONFIG_SCHEDSTATS */
+static inline void init_schedstats(void) {}
+#endif /* CONFIG_SCHEDSTATS */
+
+/*
+ * wake_up_new_task - wake up a newly created task for the first time.
+ *
+ * This function will do some initial scheduler statistics housekeeping
+ * that must be done for every newly created context, then puts the task
+ * on the runqueue and wakes it.
+ */
+void wake_up_new_task(struct task_struct *p)
+{
+	unsigned long flags;
+	struct rq *rq;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+
+	p->state = TASK_RUNNING;
+
+	rq = cpu_rq(select_task_rq(p, this_rq()));
+#ifdef CONFIG_SMP
+	rseq_migrate(p);
+	/*
+	 * Fork balancing, do it here and not earlier because:
+	 * - cpus_ptr can change in the fork path
+	 * - any previously selected CPU might disappear through hotplug
+	 * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq,
+	 * as we're not fully set-up yet.
+	 */
+	__set_task_cpu(p, cpu_of(rq));
+#endif
+
+	raw_spin_lock(&rq->lock);
+
+	update_rq_clock(rq);
+	activate_task(p, rq);
+	trace_sched_wakeup_new(p);
+	check_preempt_curr(rq);
+
+	raw_spin_unlock(&rq->lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+static DEFINE_STATIC_KEY_FALSE(preempt_notifier_key);
+
+void preempt_notifier_inc(void)
+{
+	static_branch_inc(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_inc);
+
+void preempt_notifier_dec(void)
+{
+	static_branch_dec(&preempt_notifier_key);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_dec);
+
+/**
+ * preempt_notifier_register - tell me when current is being preempted & rescheduled
+ * @notifier: notifier struct to register
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+	if (!static_branch_unlikely(&preempt_notifier_key))
+		WARN(1, "registering preempt_notifier while notifiers disabled\n");
+
+	hlist_add_head(&notifier->link, &current->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ * @notifier: notifier struct to unregister
+ *
+ * This is *not* safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+	hlist_del(&notifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void __fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+	if (static_branch_unlikely(&preempt_notifier_key))
+		__fire_sched_in_preempt_notifiers(curr);
+}
+
+static void
+__fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				   struct task_struct *next)
+{
+	struct preempt_notifier *notifier;
+
+	hlist_for_each_entry(notifier, &curr->preempt_notifiers, link)
+		notifier->ops->sched_out(notifier, next);
+}
+
+static __always_inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+	if (static_branch_unlikely(&preempt_notifier_key))
+		__fire_sched_out_preempt_notifiers(curr, next);
+}
+
+#else /* !CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static inline void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+				 struct task_struct *next)
+{
+}
+
+#endif /* CONFIG_PREEMPT_NOTIFIERS */
+
+static inline void prepare_task(struct task_struct *next)
+{
+	/*
+	 * Claim the task as running, we do this before switching to it
+	 * such that any running task will have this set.
+	 *
+	 * See the ttwu() WF_ON_CPU case and its ordering comment.
+	 */
+	WRITE_ONCE(next->on_cpu, 1);
+}
+
+static inline void finish_task(struct task_struct *prev)
+{
+#ifdef CONFIG_SMP
+	/*
+	 * This must be the very last reference to @prev from this CPU. After
+	 * p->on_cpu is cleared, the task can be moved to a different CPU. We
+	 * must ensure this doesn't happen until the switch is completely
+	 * finished.
+	 *
+	 * In particular, the load of prev->state in finish_task_switch() must
+	 * happen before this.
+	 *
+	 * Pairs with the smp_cond_load_acquire() in try_to_wake_up().
+	 */
+	smp_store_release(&prev->on_cpu, 0);
+#else
+	prev->on_cpu = 0;
+#endif
+}
+
+static inline void
+prepare_lock_switch(struct rq *rq, struct task_struct *next)
+{
+	/*
+	 * Since the runqueue lock will be released by the next
+	 * task (which is an invalid locking op but in the case
+	 * of the scheduler it's an obvious special-case), so we
+	 * do an early lockdep release here:
+	 */
+	spin_release(&rq->lock.dep_map, _THIS_IP_);
+#ifdef CONFIG_DEBUG_SPINLOCK
+	/* this is a valid case when another task releases the spinlock */
+	rq->lock.owner = next;
+#endif
+}
+
+static inline void finish_lock_switch(struct rq *rq)
+{
+	/*
+	 * If we are tracking spinlock dependencies then we have to
+	 * fix up the runqueue lock - which gets 'carried over' from
+	 * prev into current:
+	 */
+	spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
+	raw_spin_unlock_irq(&rq->lock);
+}
+
+/**
+ * prepare_task_switch - prepare to switch tasks
+ * @rq: the runqueue preparing to switch
+ * @next: the task we are going to switch to.
+ *
+ * This is called with the rq lock held and interrupts off. It must
+ * be paired with a subsequent finish_task_switch after the context
+ * switch.
+ *
+ * prepare_task_switch sets up locking and calls architecture specific
+ * hooks.
+ */
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+		    struct task_struct *next)
+{
+	kcov_prepare_switch(prev);
+	sched_info_switch(rq, prev, next);
+	perf_event_task_sched_out(prev, next);
+	rseq_preempt(prev);
+	fire_sched_out_preempt_notifiers(prev, next);
+	prepare_task(next);
+	prepare_arch_switch(next);
+}
+
+/**
+ * finish_task_switch - clean up after a task-switch
+ * @rq: runqueue associated with task-switch
+ * @prev: the thread we just switched away from.
+ *
+ * finish_task_switch must be called after the context switch, paired
+ * with a prepare_task_switch call before the context switch.
+ * finish_task_switch will reconcile locking set up by prepare_task_switch,
+ * and do any other architecture-specific cleanup actions.
+ *
+ * Note that we may have delayed dropping an mm in context_switch(). If
+ * so, we finish that here outside of the runqueue lock.  (Doing it
+ * with the lock held can cause deadlocks; see schedule() for
+ * details.)
+ *
+ * The context switch have flipped the stack from under us and restored the
+ * local variables which were saved when this task called schedule() in the
+ * past. prev == current is still correct but we need to recalculate this_rq
+ * because prev may have moved to another CPU.
+ */
+static struct rq *finish_task_switch(struct task_struct *prev)
+	__releases(rq->lock)
+{
+	struct rq *rq = this_rq();
+	struct mm_struct *mm = rq->prev_mm;
+	long prev_state;
+
+	/*
+	 * The previous task will have left us with a preempt_count of 2
+	 * because it left us after:
+	 *
+	 *	schedule()
+	 *	  preempt_disable();			// 1
+	 *	  __schedule()
+	 *	    raw_spin_lock_irq(&rq->lock)	// 2
+	 *
+	 * Also, see FORK_PREEMPT_COUNT.
+	 */
+	if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET,
+		      "corrupted preempt_count: %s/%d/0x%x\n",
+		      current->comm, current->pid, preempt_count()))
+		preempt_count_set(FORK_PREEMPT_COUNT);
+
+	rq->prev_mm = NULL;
+
+	/*
+	 * A task struct has one reference for the use as "current".
+	 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
+	 * schedule one last time. The schedule call will never return, and
+	 * the scheduled task must drop that reference.
+	 *
+	 * We must observe prev->state before clearing prev->on_cpu (in
+	 * finish_task), otherwise a concurrent wakeup can get prev
+	 * running on another CPU and we could rave with its RUNNING -> DEAD
+	 * transition, resulting in a double drop.
+	 */
+	prev_state = prev->state;
+	vtime_task_switch(prev);
+	perf_event_task_sched_in(prev, current);
+	finish_task(prev);
+	finish_lock_switch(rq);
+	finish_arch_post_lock_switch();
+	kcov_finish_switch(current);
+
+	fire_sched_in_preempt_notifiers(current);
+	/*
+	 * When switching through a kernel thread, the loop in
+	 * membarrier_{private,global}_expedited() may have observed that
+	 * kernel thread and not issued an IPI. It is therefore possible to
+	 * schedule between user->kernel->user threads without passing though
+	 * switch_mm(). Membarrier requires a barrier after storing to
+	 * rq->curr, before returning to userspace, so provide them here:
+	 *
+	 * - a full memory barrier for {PRIVATE,GLOBAL}_EXPEDITED, implicitly
+	 *   provided by mmdrop(),
+	 * - a sync_core for SYNC_CORE.
+	 */
+	if (mm) {
+		membarrier_mm_sync_core_before_usermode(mm);
+		mmdrop(mm);
+	}
+	if (unlikely(prev_state == TASK_DEAD)) {
+		/*
+		 * Remove function-return probe instances associated with this
+		 * task and put them back on the free list.
+		 */
+		kprobe_flush_task(prev);
+
+		/* Task is done with its stack. */
+		put_task_stack(prev);
+
+		put_task_struct_rcu_user(prev);
+	}
+
+	tick_nohz_task_switch();
+	return rq;
+}
+
+/**
+ * schedule_tail - first thing a freshly forked thread must call.
+ * @prev: the thread we just switched away from.
+ */
+asmlinkage __visible void schedule_tail(struct task_struct *prev)
+	__releases(rq->lock)
+{
+	struct rq *rq;
+
+	/*
+	 * New tasks start with FORK_PREEMPT_COUNT, see there and
+	 * finish_task_switch() for details.
+	 *
+	 * finish_task_switch() will drop rq->lock() and lower preempt_count
+	 * and the preempt_enable() will end up enabling preemption (on
+	 * PREEMPT_COUNT kernels).
+	 */
+
+	rq = finish_task_switch(prev);
+	preempt_enable();
+
+	if (current->set_child_tid)
+		put_user(task_pid_vnr(current), current->set_child_tid);
+
+	calculate_sigpending();
+}
+
+/*
+ * context_switch - switch to the new MM and the new thread's register state.
+ */
+static __always_inline struct rq *
+context_switch(struct rq *rq, struct task_struct *prev,
+	       struct task_struct *next)
+{
+	prepare_task_switch(rq, prev, next);
+
+	/*
+	 * For paravirt, this is coupled with an exit in switch_to to
+	 * combine the page table reload and the switch backend into
+	 * one hypercall.
+	 */
+	arch_start_context_switch(prev);
+
+	/*
+	 * kernel -> kernel   lazy + transfer active
+	 *   user -> kernel   lazy + mmgrab() active
+	 *
+	 * kernel ->   user   switch + mmdrop() active
+	 *   user ->   user   switch
+	 */
+	if (!next->mm) {                                // to kernel
+		enter_lazy_tlb(prev->active_mm, next);
+
+		next->active_mm = prev->active_mm;
+		if (prev->mm)                           // from user
+			mmgrab(prev->active_mm);
+		else
+			prev->active_mm = NULL;
+	} else {                                        // to user
+		membarrier_switch_mm(rq, prev->active_mm, next->mm);
+		/*
+		 * sys_membarrier() requires an smp_mb() between setting
+		 * rq->curr / membarrier_switch_mm() and returning to userspace.
+		 *
+		 * The below provides this either through switch_mm(), or in
+		 * case 'prev->active_mm == next->mm' through
+		 * finish_task_switch()'s mmdrop().
+		 */
+		switch_mm_irqs_off(prev->active_mm, next->mm, next);
+
+		if (!prev->mm) {                        // from kernel
+			/* will mmdrop() in finish_task_switch(). */
+			rq->prev_mm = prev->active_mm;
+			prev->active_mm = NULL;
+		}
+	}
+
+	prepare_lock_switch(rq, next);
+
+	/* Here we just switch the register state and the stack. */
+	switch_to(prev, next, prev);
+	barrier();
+
+	return finish_task_switch(prev);
+}
+
+/*
+ * nr_running, nr_uninterruptible and nr_context_switches:
+ *
+ * externally visible scheduler statistics: current number of runnable
+ * threads, total number of context switches performed since bootup.
+ */
+unsigned long nr_running(void)
+{
+	unsigned long i, sum = 0;
+
+	for_each_online_cpu(i)
+		sum += cpu_rq(i)->nr_running;
+
+	return sum;
+}
+
+/*
+ * Check if only the current task is running on the CPU.
+ *
+ * Caution: this function does not check that the caller has disabled
+ * preemption, thus the result might have a time-of-check-to-time-of-use
+ * race.  The caller is responsible to use it correctly, for example:
+ *
+ * - from a non-preemptible section (of course)
+ *
+ * - from a thread that is bound to a single CPU
+ *
+ * - in a loop with very short iterations (e.g. a polling loop)
+ */
+bool single_task_running(void)
+{
+	return raw_rq()->nr_running == 1;
+}
+EXPORT_SYMBOL(single_task_running);
+
+unsigned long long nr_context_switches(void)
+{
+	int i;
+	unsigned long long sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += cpu_rq(i)->nr_switches;
+
+	return sum;
+}
+
+/*
+ * Consumers of these two interfaces, like for example the cpuidle menu
+ * governor, are using nonsensical data. Preferring shallow idle state selection
+ * for a CPU that has IO-wait which might not even end up running the task when
+ * it does become runnable.
+ */
+
+unsigned long nr_iowait_cpu(int cpu)
+{
+	return atomic_read(&cpu_rq(cpu)->nr_iowait);
+}
+
+/*
+ * IO-wait accounting, and how its mostly bollocks (on SMP).
+ *
+ * The idea behind IO-wait account is to account the idle time that we could
+ * have spend running if it were not for IO. That is, if we were to improve the
+ * storage performance, we'd have a proportional reduction in IO-wait time.
+ *
+ * This all works nicely on UP, where, when a task blocks on IO, we account
+ * idle time as IO-wait, because if the storage were faster, it could've been
+ * running and we'd not be idle.
+ *
+ * This has been extended to SMP, by doing the same for each CPU. This however
+ * is broken.
+ *
+ * Imagine for instance the case where two tasks block on one CPU, only the one
+ * CPU will have IO-wait accounted, while the other has regular idle. Even
+ * though, if the storage were faster, both could've ran at the same time,
+ * utilising both CPUs.
+ *
+ * This means, that when looking globally, the current IO-wait accounting on
+ * SMP is a lower bound, by reason of under accounting.
+ *
+ * Worse, since the numbers are provided per CPU, they are sometimes
+ * interpreted per CPU, and that is nonsensical. A blocked task isn't strictly
+ * associated with any one particular CPU, it can wake to another CPU than it
+ * blocked on. This means the per CPU IO-wait number is meaningless.
+ *
+ * Task CPU affinities can make all that even more 'interesting'.
+ */
+
+unsigned long nr_iowait(void)
+{
+	unsigned long i, sum = 0;
+
+	for_each_possible_cpu(i)
+		sum += nr_iowait_cpu(i);
+
+	return sum;
+}
+
+#ifdef CONFIG_SMP
+
+/*
+ * sched_exec - execve() is a valuable balancing opportunity, because at
+ * this point the task has the smallest effective memory and cache
+ * footprint.
+ */
+void sched_exec(void)
+{
+	struct task_struct *p = current;
+	unsigned long flags;
+	int dest_cpu;
+	struct rq *rq;
+
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	rq = this_rq();
+
+	if (rq != task_rq(p) || rq->nr_running < 2)
+		goto unlock;
+
+	dest_cpu = select_task_rq(p, task_rq(p));
+	if (dest_cpu == smp_processor_id())
+		goto unlock;
+
+	if (likely(cpu_active(dest_cpu))) {
+		struct migration_arg arg = { p, dest_cpu };
+
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg);
+		return;
+	}
+unlock:
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+
+#endif
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+EXPORT_PER_CPU_SYMBOL(kernel_cpustat);
+
+static inline void update_curr(struct rq *rq, struct task_struct *p)
+{
+	s64 ns = rq->clock_task - p->last_ran;
+
+	p->sched_time += ns;
+	account_group_exec_runtime(p, ns);
+
+	p->time_slice -= ns;
+	p->last_ran = rq->clock_task;
+}
+
+/*
+ * Return accounted runtime for the task.
+ * Return separately the current's pending runtime that have not been
+ * accounted yet.
+ */
+unsigned long long task_sched_runtime(struct task_struct *p)
+{
+	unsigned long flags;
+	struct rq *rq;
+	raw_spinlock_t *lock;
+	u64 ns;
+
+#if defined(CONFIG_64BIT) && defined(CONFIG_SMP)
+	/*
+	 * 64-bit doesn't need locks to atomically read a 64-bit value.
+	 * So we have a optimization chance when the task's delta_exec is 0.
+	 * Reading ->on_cpu is racy, but this is ok.
+	 *
+	 * If we race with it leaving CPU, we'll take a lock. So we're correct.
+	 * If we race with it entering CPU, unaccounted time is 0. This is
+	 * indistinguishable from the read occurring a few cycles earlier.
+	 * If we see ->on_cpu without ->on_rq, the task is leaving, and has
+	 * been accounted, so we're correct here as well.
+	 */
+	if (!p->on_cpu || !task_on_rq_queued(p))
+		return tsk_seruntime(p);
+#endif
+
+	rq = task_access_lock_irqsave(p, &lock, &flags);
+	/*
+	 * Must be ->curr _and_ ->on_rq.  If dequeued, we would
+	 * project cycles that may never be accounted to this
+	 * thread, breaking clock_gettime().
+	 */
+	if (p == rq->curr && task_on_rq_queued(p)) {
+		update_rq_clock(rq);
+		update_curr(rq, p);
+	}
+	ns = tsk_seruntime(p);
+	task_access_unlock_irqrestore(p, lock, &flags);
+
+	return ns;
+}
+
+/* This manages tasks that have run out of timeslice during a scheduler_tick */
+static inline void scheduler_task_tick(struct rq *rq)
+{
+	struct task_struct *p = rq->curr;
+
+	if (is_idle_task(p))
+		return;
+
+	update_curr(rq, p);
+	cpufreq_update_util(rq, 0);
+
+	/*
+	 * Tasks have less than RESCHED_NS of time slice left they will be
+	 * rescheduled.
+	 */
+	if (p->time_slice >= RESCHED_NS)
+		return;
+	set_tsk_need_resched(p);
+	set_preempt_need_resched();
+}
+
+/*
+ * This function gets called by the timer code, with HZ frequency.
+ * We call it with interrupts disabled.
+ */
+void scheduler_tick(void)
+{
+	int cpu __maybe_unused = smp_processor_id();
+	struct rq *rq = cpu_rq(cpu);
+
+	arch_scale_freq_tick();
+	sched_clock_tick();
+
+	raw_spin_lock(&rq->lock);
+	update_rq_clock(rq);
+
+	scheduler_task_tick(rq);
+	calc_global_load_tick(rq);
+	psi_task_tick(rq);
+
+	rq->last_tick = rq->clock;
+	raw_spin_unlock(&rq->lock);
+
+	perf_event_task_tick();
+}
+
+#ifdef CONFIG_SCHED_SMT
+static inline int active_load_balance_cpu_stop(void *data)
+{
+	struct rq *rq = this_rq();
+	struct task_struct *p = data;
+	cpumask_t tmp;
+	unsigned long flags;
+
+	local_irq_save(flags);
+
+	raw_spin_lock(&p->pi_lock);
+	raw_spin_lock(&rq->lock);
+
+	rq->active_balance = 0;
+	/* _something_ may have changed the task, double check again */
+	if (task_on_rq_queued(p) && task_rq(p) == rq &&
+	    cpumask_and(&tmp, p->cpus_ptr, &sched_sg_idle_mask)) {
+		int cpu = cpu_of(rq);
+		int dcpu = __best_mask_cpu(cpu, &tmp,
+					   per_cpu(sched_cpu_llc_mask, cpu));
+		rq = move_queued_task(rq, p, dcpu);
+	}
+
+	raw_spin_unlock(&rq->lock);
+	raw_spin_unlock(&p->pi_lock);
+
+	local_irq_restore(flags);
+
+	return 0;
+}
+
+/* sg_balance_trigger - trigger slibing group balance for @cpu */
+static inline int sg_balance_trigger(const int cpu)
+{
+	struct rq *rq= cpu_rq(cpu);
+	unsigned long flags;
+	struct task_struct *curr;
+	int res;
+
+	if (!raw_spin_trylock_irqsave(&rq->lock, flags))
+		return 0;
+	curr = rq->curr;
+	res = (!is_idle_task(curr)) && (1 == rq->nr_running) &&\
+	      cpumask_intersects(curr->cpus_ptr, &sched_sg_idle_mask) &&\
+	      (!rq->active_balance);
+
+	if (res)
+		rq->active_balance = 1;
+
+	raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+	if (res)
+		stop_one_cpu_nowait(cpu, active_load_balance_cpu_stop,
+				    curr, &rq->active_balance_work);
+	return res;
+}
+
+/*
+ * sg_balance_check - slibing group balance check for run queue @rq
+ */
+static inline void sg_balance_check(struct rq *rq)
+{
+	cpumask_t chk;
+	int cpu;
+
+	/* exit when no sg in idle */
+	if (cpumask_empty(&sched_sg_idle_mask))
+		return;
+
+	cpu = cpu_of(rq);
+	/*
+	 * Only cpu in slibing idle group will do the checking and then
+	 * find potential cpus which can migrate the current running task
+	 */
+	if (cpumask_test_cpu(cpu, &sched_sg_idle_mask) &&
+	    cpumask_andnot(&chk, cpu_online_mask, &sched_rq_pending_mask) &&
+	    cpumask_andnot(&chk, &chk, &sched_rq_watermark[IDLE_WM])) {
+		int i, tried = 0;
+
+		for_each_cpu_wrap(i, &chk, cpu) {
+			if (cpumask_subset(cpu_smt_mask(i), &chk)) {
+				if (sg_balance_trigger(i))
+					return;
+				if (tried)
+					return;
+				tried++;
+			}
+		}
+	}
+}
+#endif /* CONFIG_SCHED_SMT */
+
+#ifdef CONFIG_NO_HZ_FULL
+
+struct tick_work {
+	int			cpu;
+	atomic_t		state;
+	struct delayed_work	work;
+};
+/* Values for ->state, see diagram below. */
+#define TICK_SCHED_REMOTE_OFFLINE	0
+#define TICK_SCHED_REMOTE_OFFLINING	1
+#define TICK_SCHED_REMOTE_RUNNING	2
+
+/*
+ * State diagram for ->state:
+ *
+ *
+ *          TICK_SCHED_REMOTE_OFFLINE
+ *                    |   ^
+ *                    |   |
+ *                    |   | sched_tick_remote()
+ *                    |   |
+ *                    |   |
+ *                    +--TICK_SCHED_REMOTE_OFFLINING
+ *                    |   ^
+ *                    |   |
+ * sched_tick_start() |   | sched_tick_stop()
+ *                    |   |
+ *                    V   |
+ *          TICK_SCHED_REMOTE_RUNNING
+ *
+ *
+ * Other transitions get WARN_ON_ONCE(), except that sched_tick_remote()
+ * and sched_tick_start() are happy to leave the state in RUNNING.
+ */
+
+static struct tick_work __percpu *tick_work_cpu;
+
+static void sched_tick_remote(struct work_struct *work)
+{
+	struct delayed_work *dwork = to_delayed_work(work);
+	struct tick_work *twork = container_of(dwork, struct tick_work, work);
+	int cpu = twork->cpu;
+	struct rq *rq = cpu_rq(cpu);
+	struct task_struct *curr;
+	unsigned long flags;
+	u64 delta;
+	int os;
+
+	/*
+	 * Handle the tick only if it appears the remote CPU is running in full
+	 * dynticks mode. The check is racy by nature, but missing a tick or
+	 * having one too much is no big deal because the scheduler tick updates
+	 * statistics and checks timeslices in a time-independent way, regardless
+	 * of when exactly it is running.
+	 */
+	if (!tick_nohz_tick_stopped_cpu(cpu))
+		goto out_requeue;
+
+	raw_spin_lock_irqsave(&rq->lock, flags);
+	curr = rq->curr;
+	if (cpu_is_offline(cpu))
+		goto out_unlock;
+
+	update_rq_clock(rq);
+	if (!is_idle_task(curr)) {
+		/*
+		 * Make sure the next tick runs within a reasonable
+		 * amount of time.
+		 */
+		delta = rq_clock_task(rq) - curr->last_ran;
+		WARN_ON_ONCE(delta > (u64)NSEC_PER_SEC * 3);
+	}
+	scheduler_task_tick(rq);
+
+	calc_load_nohz_remote(rq);
+out_unlock:
+	raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+out_requeue:
+	/*
+	 * Run the remote tick once per second (1Hz). This arbitrary
+	 * frequency is large enough to avoid overload but short enough
+	 * to keep scheduler internal stats reasonably up to date.  But
+	 * first update state to reflect hotplug activity if required.
+	 */
+	os = atomic_fetch_add_unless(&twork->state, -1, TICK_SCHED_REMOTE_RUNNING);
+	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_OFFLINE);
+	if (os == TICK_SCHED_REMOTE_RUNNING)
+		queue_delayed_work(system_unbound_wq, dwork, HZ);
+}
+
+static void sched_tick_start(int cpu)
+{
+	int os;
+	struct tick_work *twork;
+
+	if (housekeeping_cpu(cpu, HK_FLAG_TICK))
+		return;
+
+	WARN_ON_ONCE(!tick_work_cpu);
+
+	twork = per_cpu_ptr(tick_work_cpu, cpu);
+	os = atomic_xchg(&twork->state, TICK_SCHED_REMOTE_RUNNING);
+	WARN_ON_ONCE(os == TICK_SCHED_REMOTE_RUNNING);
+	if (os == TICK_SCHED_REMOTE_OFFLINE) {
+		twork->cpu = cpu;
+		INIT_DELAYED_WORK(&twork->work, sched_tick_remote);
+		queue_delayed_work(system_unbound_wq, &twork->work, HZ);
+	}
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+static void sched_tick_stop(int cpu)
+{
+	struct tick_work *twork;
+
+	if (housekeeping_cpu(cpu, HK_FLAG_TICK))
+		return;
+
+	WARN_ON_ONCE(!tick_work_cpu);
+
+	twork = per_cpu_ptr(tick_work_cpu, cpu);
+	cancel_delayed_work_sync(&twork->work);
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+int __init sched_tick_offload_init(void)
+{
+	tick_work_cpu = alloc_percpu(struct tick_work);
+	BUG_ON(!tick_work_cpu);
+	return 0;
+}
+
+#else /* !CONFIG_NO_HZ_FULL */
+static inline void sched_tick_start(int cpu) { }
+static inline void sched_tick_stop(int cpu) { }
+#endif
+
+#if defined(CONFIG_PREEMPTION) && (defined(CONFIG_DEBUG_PREEMPT) || \
+				defined(CONFIG_PREEMPT_TRACER))
+/*
+ * If the value passed in is equal to the current preempt count
+ * then we just disabled preemption. Start timing the latency.
+ */
+static inline void preempt_latency_start(int val)
+{
+	if (preempt_count() == val) {
+		unsigned long ip = get_lock_parent_ip();
+#ifdef CONFIG_DEBUG_PREEMPT
+		current->preempt_disable_ip = ip;
+#endif
+		trace_preempt_off(CALLER_ADDR0, ip);
+	}
+}
+
+void preempt_count_add(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
+		return;
+#endif
+	__preempt_count_add(val);
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Spinlock count overflowing soon?
+	 */
+	DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
+				PREEMPT_MASK - 10);
+#endif
+	preempt_latency_start(val);
+}
+EXPORT_SYMBOL(preempt_count_add);
+NOKPROBE_SYMBOL(preempt_count_add);
+
+/*
+ * If the value passed in equals to the current preempt count
+ * then we just enabled preemption. Stop timing the latency.
+ */
+static inline void preempt_latency_stop(int val)
+{
+	if (preempt_count() == val)
+		trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip());
+}
+
+void preempt_count_sub(int val)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	/*
+	 * Underflow?
+	 */
+	if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
+		return;
+	/*
+	 * Is the spinlock portion underflowing?
+	 */
+	if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+			!(preempt_count() & PREEMPT_MASK)))
+		return;
+#endif
+
+	preempt_latency_stop(val);
+	__preempt_count_sub(val);
+}
+EXPORT_SYMBOL(preempt_count_sub);
+NOKPROBE_SYMBOL(preempt_count_sub);
+
+#else
+static inline void preempt_latency_start(int val) { }
+static inline void preempt_latency_stop(int val) { }
+#endif
+
+static inline unsigned long get_preempt_disable_ip(struct task_struct *p)
+{
+#ifdef CONFIG_DEBUG_PREEMPT
+	return p->preempt_disable_ip;
+#else
+	return 0;
+#endif
+}
+
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
+{
+	/* Save this before calling printk(), since that will clobber it */
+	unsigned long preempt_disable_ip = get_preempt_disable_ip(current);
+
+	if (oops_in_progress)
+		return;
+
+	printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
+		prev->comm, prev->pid, preempt_count());
+
+	debug_show_held_locks(prev);
+	print_modules();
+	if (irqs_disabled())
+		print_irqtrace_events(prev);
+	if (IS_ENABLED(CONFIG_DEBUG_PREEMPT)
+	    && in_atomic_preempt_off()) {
+		pr_err("Preemption disabled at:");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
+	}
+	if (panic_on_warn)
+		panic("scheduling while atomic\n");
+
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+
+/*
+ * Various schedule()-time debugging checks and statistics:
+ */
+static inline void schedule_debug(struct task_struct *prev, bool preempt)
+{
+#ifdef CONFIG_SCHED_STACK_END_CHECK
+	if (task_stack_end_corrupted(prev))
+		panic("corrupted stack end detected inside scheduler\n");
+
+	if (task_scs_end_corrupted(prev))
+		panic("corrupted shadow stack detected inside scheduler\n");
+#endif
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+	if (!preempt && prev->state && prev->non_block_count) {
+		printk(KERN_ERR "BUG: scheduling in a non-blocking section: %s/%d/%i\n",
+			prev->comm, prev->pid, prev->non_block_count);
+		dump_stack();
+		add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+	}
+#endif
+
+	if (unlikely(in_atomic_preempt_off())) {
+		__schedule_bug(prev);
+		preempt_count_set(PREEMPT_DISABLED);
+	}
+	rcu_sleep_check();
+
+	profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+	schedstat_inc(this_rq()->sched_count);
+}
+
+/*
+ * Compile time debug macro
+ * #define ALT_SCHED_DEBUG
+ */
+
+#ifdef ALT_SCHED_DEBUG
+void alt_sched_debug(void)
+{
+	printk(KERN_INFO "sched: pending: 0x%04lx, idle: 0x%04lx, sg_idle: 0x%04lx\n",
+	       sched_rq_pending_mask.bits[0],
+	       sched_rq_watermark[IDLE_WM].bits[0],
+	       sched_sg_idle_mask.bits[0]);
+}
+#else
+inline void alt_sched_debug(void) {}
+#endif
+
+#ifdef	CONFIG_SMP
+
+#define SCHED_RQ_NR_MIGRATION (32UL)
+/*
+ * Migrate pending tasks in @rq to @dest_cpu
+ * Will try to migrate mininal of half of @rq nr_running tasks and
+ * SCHED_RQ_NR_MIGRATION to @dest_cpu
+ */
+static inline int
+migrate_pending_tasks(struct rq *rq, struct rq *dest_rq, const int dest_cpu)
+{
+	struct task_struct *p, *skip = rq->curr;
+	int nr_migrated = 0;
+	int nr_tries = min(rq->nr_running / 2, SCHED_RQ_NR_MIGRATION);
+
+	while (skip != rq->idle && nr_tries &&
+	       (p = sched_rq_next_task(skip, rq)) != rq->idle) {
+		skip = sched_rq_next_task(p, rq);
+		if (cpumask_test_cpu(dest_cpu, p->cpus_ptr)) {
+			__SCHED_DEQUEUE_TASK(p, rq, 0, );
+			set_task_cpu(p, dest_cpu);
+			__SCHED_ENQUEUE_TASK(p, dest_rq, 0);
+			nr_migrated++;
+		}
+		nr_tries--;
+	}
+
+	return nr_migrated;
+}
+
+static inline int take_other_rq_tasks(struct rq *rq, int cpu)
+{
+	struct cpumask *affinity_mask, *end_mask;
+
+	if (unlikely(!rq->online))
+		return 0;
+
+	if (cpumask_empty(&sched_rq_pending_mask))
+		return 0;
+
+	affinity_mask = &(per_cpu(sched_cpu_affinity_masks, cpu)[0]);
+	end_mask = per_cpu(sched_cpu_affinity_end_mask, cpu);
+	do {
+		int i;
+		for_each_cpu_and(i, &sched_rq_pending_mask, affinity_mask) {
+			int nr_migrated;
+			struct rq *src_rq;
+
+			src_rq = cpu_rq(i);
+			if (!do_raw_spin_trylock(&src_rq->lock))
+				continue;
+			spin_acquire(&src_rq->lock.dep_map,
+				     SINGLE_DEPTH_NESTING, 1, _RET_IP_);
+
+			if ((nr_migrated = migrate_pending_tasks(src_rq, rq, cpu))) {
+				src_rq->nr_running -= nr_migrated;
+#ifdef CONFIG_SMP
+				if (src_rq->nr_running < 2)
+					cpumask_clear_cpu(i, &sched_rq_pending_mask);
+#endif
+				rq->nr_running += nr_migrated;
+#ifdef CONFIG_SMP
+				if (rq->nr_running > 1)
+					cpumask_set_cpu(cpu, &sched_rq_pending_mask);
+#endif
+				update_sched_rq_watermark(rq);
+				cpufreq_update_util(rq, 0);
+
+				spin_release(&src_rq->lock.dep_map, _RET_IP_);
+				do_raw_spin_unlock(&src_rq->lock);
+
+				return 1;
+			}
+
+			spin_release(&src_rq->lock.dep_map, _RET_IP_);
+			do_raw_spin_unlock(&src_rq->lock);
+		}
+	} while (++affinity_mask < end_mask);
+
+	return 0;
+}
+#endif
+
+/*
+ * Timeslices below RESCHED_NS are considered as good as expired as there's no
+ * point rescheduling when there's so little time left.
+ */
+static inline void check_curr(struct task_struct *p, struct rq *rq)
+{
+	if (unlikely(rq->idle == p))
+		return;
+
+	update_curr(rq, p);
+
+	if (p->time_slice < RESCHED_NS)
+		time_slice_expired(p, rq);
+}
+
+static inline struct task_struct *
+choose_next_task(struct rq *rq, int cpu, struct task_struct *prev)
+{
+	struct task_struct *next;
+
+	if (unlikely(rq->skip)) {
+		next = rq_runnable_task(rq);
+		if (next == rq->idle) {
+#ifdef	CONFIG_SMP
+			if (!take_other_rq_tasks(rq, cpu)) {
+#endif
+				rq->skip = NULL;
+				schedstat_inc(rq->sched_goidle);
+				return next;
+#ifdef	CONFIG_SMP
+			}
+			next = rq_runnable_task(rq);
+#endif
+		}
+		rq->skip = NULL;
+#ifdef CONFIG_HIGH_RES_TIMERS
+		hrtick_start(rq, next->time_slice);
+#endif
+		return next;
+	}
+
+	next = sched_rq_first_task(rq);
+	if (next == rq->idle) {
+#ifdef	CONFIG_SMP
+		if (!take_other_rq_tasks(rq, cpu)) {
+#endif
+			schedstat_inc(rq->sched_goidle);
+			/*printk(KERN_INFO "sched: choose_next_task(%d) idle %px\n", cpu, next);*/
+			return next;
+#ifdef	CONFIG_SMP
+		}
+		next = sched_rq_first_task(rq);
+#endif
+	}
+#ifdef CONFIG_HIGH_RES_TIMERS
+	hrtick_start(rq, next->time_slice);
+#endif
+	/*printk(KERN_INFO "sched: choose_next_task(%d) next %px\n", cpu,
+	 * next);*/
+	return next;
+}
+
+/*
+ * schedule() is the main scheduler function.
+ *
+ * The main means of driving the scheduler and thus entering this function are:
+ *
+ *   1. Explicit blocking: mutex, semaphore, waitqueue, etc.
+ *
+ *   2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return
+ *      paths. For example, see arch/x86/entry_64.S.
+ *
+ *      To drive preemption between tasks, the scheduler sets the flag in timer
+ *      interrupt handler scheduler_tick().
+ *
+ *   3. Wakeups don't really cause entry into schedule(). They add a
+ *      task to the run-queue and that's it.
+ *
+ *      Now, if the new task added to the run-queue preempts the current
+ *      task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets
+ *      called on the nearest possible occasion:
+ *
+ *       - If the kernel is preemptible (CONFIG_PREEMPTION=y):
+ *
+ *         - in syscall or exception context, at the next outmost
+ *           preempt_enable(). (this might be as soon as the wake_up()'s
+ *           spin_unlock()!)
+ *
+ *         - in IRQ context, return from interrupt-handler to
+ *           preemptible context
+ *
+ *       - If the kernel is not preemptible (CONFIG_PREEMPTION is not set)
+ *         then at the next:
+ *
+ *          - cond_resched() call
+ *          - explicit schedule() call
+ *          - return from syscall or exception to user-space
+ *          - return from interrupt-handler to user-space
+ *
+ * WARNING: must be called with preemption disabled!
+ */
+static void __sched notrace __schedule(bool preempt)
+{
+	struct task_struct *prev, *next;
+	unsigned long *switch_count;
+	unsigned long prev_state;
+	struct rq *rq;
+	int cpu;
+
+	cpu = smp_processor_id();
+	rq = cpu_rq(cpu);
+	prev = rq->curr;
+
+	schedule_debug(prev, preempt);
+
+	/* by passing sched_feat(HRTICK) checking which Alt schedule FW doesn't support */
+	hrtick_clear(rq);
+
+	local_irq_disable();
+	rcu_note_context_switch(preempt);
+
+	/*
+	 * Make sure that signal_pending_state()->signal_pending() below
+	 * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE)
+	 * done by the caller to avoid the race with signal_wake_up():
+	 *
+	 * __set_current_state(@state)		signal_wake_up()
+	 * schedule()				  set_tsk_thread_flag(p, TIF_SIGPENDING)
+	 *					  wake_up_state(p, state)
+	 *   LOCK rq->lock			    LOCK p->pi_state
+	 *   smp_mb__after_spinlock()		    smp_mb__after_spinlock()
+	 *     if (signal_pending_state())	    if (p->state & @state)
+	 *
+	 * Also, the membarrier system call requires a full memory barrier
+	 * after coming from user-space, before storing to rq->curr.
+	 */
+	raw_spin_lock(&rq->lock);
+	smp_mb__after_spinlock();
+
+	update_rq_clock(rq);
+
+	switch_count = &prev->nivcsw;
+	/*
+	 * We must load prev->state once (task_struct::state is volatile), such
+	 * that:
+	 *
+	 *  - we form a control dependency vs deactivate_task() below.
+	 *  - ptrace_{,un}freeze_traced() can change ->state underneath us.
+	 */
+	prev_state = prev->state;
+	if (!preempt && prev_state && prev_state == prev->state) {
+		if (signal_pending_state(prev_state, prev)) {
+			prev->state = TASK_RUNNING;
+		} else {
+			prev->sched_contributes_to_load =
+				(prev_state & TASK_UNINTERRUPTIBLE) &&
+				!(prev_state & TASK_NOLOAD) &&
+				!(prev->flags & PF_FROZEN);
+
+			if (prev->sched_contributes_to_load)
+				rq->nr_uninterruptible++;
+
+			/*
+			 * __schedule()			ttwu()
+			 *   prev_state = prev->state;    if (p->on_rq && ...)
+			 *   if (prev_state)		    goto out;
+			 *     p->on_rq = 0;		  smp_acquire__after_ctrl_dep();
+			 *				  p->state = TASK_WAKING
+			 *
+			 * Where __schedule() and ttwu() have matching control dependencies.
+			 *
+			 * After this, schedule() must not care about p->state any more.
+			 */
+			sched_task_deactivate(prev, rq);
+			deactivate_task(prev, rq);
+
+			if (prev->in_iowait) {
+				atomic_inc(&rq->nr_iowait);
+				delayacct_blkio_start();
+			}
+		}
+		switch_count = &prev->nvcsw;
+	}
+
+	check_curr(prev, rq);
+
+	next = choose_next_task(rq, cpu, prev);
+	clear_tsk_need_resched(prev);
+	clear_preempt_need_resched();
+
+
+	if (likely(prev != next)) {
+		next->last_ran = rq->clock_task;
+		rq->last_ts_switch = rq->clock;
+
+		rq->nr_switches++;
+		/*
+		 * RCU users of rcu_dereference(rq->curr) may not see
+		 * changes to task_struct made by pick_next_task().
+		 */
+		RCU_INIT_POINTER(rq->curr, next);
+		/*
+		 * The membarrier system call requires each architecture
+		 * to have a full memory barrier after updating
+		 * rq->curr, before returning to user-space.
+		 *
+		 * Here are the schemes providing that barrier on the
+		 * various architectures:
+		 * - mm ? switch_mm() : mmdrop() for x86, s390, sparc, PowerPC.
+		 *   switch_mm() rely on membarrier_arch_switch_mm() on PowerPC.
+		 * - finish_lock_switch() for weakly-ordered
+		 *   architectures where spin_unlock is a full barrier,
+		 * - switch_to() for arm64 (weakly-ordered, spin_unlock
+		 *   is a RELEASE barrier),
+		 */
+		++*switch_count;
+
+		psi_sched_switch(prev, next, !task_on_rq_queued(prev));
+
+		trace_sched_switch(preempt, prev, next);
+
+		/* Also unlocks the rq: */
+		rq = context_switch(rq, prev, next);
+	} else
+		raw_spin_unlock_irq(&rq->lock);
+
+#ifdef CONFIG_SCHED_SMT
+	sg_balance_check(rq);
+#endif
+}
+
+void __noreturn do_task_dead(void)
+{
+	/* Causes final put_task_struct in finish_task_switch(): */
+	set_special_state(TASK_DEAD);
+
+	/* Tell freezer to ignore us: */
+	current->flags |= PF_NOFREEZE;
+
+	__schedule(false);
+	BUG();
+
+	/* Avoid "noreturn function does return" - but don't continue if BUG() is a NOP: */
+	for (;;)
+		cpu_relax();
+}
+
+static inline void sched_submit_work(struct task_struct *tsk)
+{
+	if (!tsk->state)
+		return;
+
+	/*
+	 * If a worker went to sleep, notify and ask workqueue whether
+	 * it wants to wake up a task to maintain concurrency.
+	 * As this function is called inside the schedule() context,
+	 * we disable preemption to avoid it calling schedule() again
+	 * in the possible wakeup of a kworker and because wq_worker_sleeping()
+	 * requires it.
+	 */
+	if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
+		preempt_disable();
+		if (tsk->flags & PF_WQ_WORKER)
+			wq_worker_sleeping(tsk);
+		else
+			io_wq_worker_sleeping(tsk);
+		preempt_enable_no_resched();
+	}
+
+	if (tsk_is_pi_blocked(tsk))
+		return;
+
+	/*
+	 * If we are going to sleep and we have plugged IO queued,
+	 * make sure to submit it to avoid deadlocks.
+	 */
+	if (blk_needs_flush_plug(tsk))
+		blk_schedule_flush_plug(tsk);
+}
+
+static void sched_update_worker(struct task_struct *tsk)
+{
+	if (tsk->flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
+		if (tsk->flags & PF_WQ_WORKER)
+			wq_worker_running(tsk);
+		else
+			io_wq_worker_running(tsk);
+	}
+}
+
+asmlinkage __visible void __sched schedule(void)
+{
+	struct task_struct *tsk = current;
+
+	sched_submit_work(tsk);
+	do {
+		preempt_disable();
+		__schedule(false);
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+	sched_update_worker(tsk);
+}
+EXPORT_SYMBOL(schedule);
+
+/*
+ * synchronize_rcu_tasks() makes sure that no task is stuck in preempted
+ * state (have scheduled out non-voluntarily) by making sure that all
+ * tasks have either left the run queue or have gone into user space.
+ * As idle tasks do not do either, they must not ever be preempted
+ * (schedule out non-voluntarily).
+ *
+ * schedule_idle() is similar to schedule_preempt_disable() except that it
+ * never enables preemption because it does not call sched_submit_work().
+ */
+void __sched schedule_idle(void)
+{
+	/*
+	 * As this skips calling sched_submit_work(), which the idle task does
+	 * regardless because that function is a nop when the task is in a
+	 * TASK_RUNNING state, make sure this isn't used someplace that the
+	 * current task can be in any other state. Note, idle is always in the
+	 * TASK_RUNNING state.
+	 */
+	WARN_ON_ONCE(current->state);
+	do {
+		__schedule(false);
+	} while (need_resched());
+}
+
+#ifdef CONFIG_CONTEXT_TRACKING
+asmlinkage __visible void __sched schedule_user(void)
+{
+	/*
+	 * If we come here after a random call to set_need_resched(),
+	 * or we have been woken up remotely but the IPI has not yet arrived,
+	 * we haven't yet exited the RCU idle mode. Do it here manually until
+	 * we find a better solution.
+	 *
+	 * NB: There are buggy callers of this function.  Ideally we
+	 * should warn if prev_state != CONTEXT_USER, but that will trigger
+	 * too frequently to make sense yet.
+	 */
+	enum ctx_state prev_state = exception_enter();
+	schedule();
+	exception_exit(prev_state);
+}
+#endif
+
+/**
+ * schedule_preempt_disabled - called with preemption disabled
+ *
+ * Returns with preemption disabled. Note: preempt_count must be 1
+ */
+void __sched schedule_preempt_disabled(void)
+{
+	sched_preempt_enable_no_resched();
+	schedule();
+	preempt_disable();
+}
+
+static void __sched notrace preempt_schedule_common(void)
+{
+	do {
+		/*
+		 * Because the function tracer can trace preempt_count_sub()
+		 * and it also uses preempt_enable/disable_notrace(), if
+		 * NEED_RESCHED is set, the preempt_enable_notrace() called
+		 * by the function tracer will call this function again and
+		 * cause infinite recursion.
+		 *
+		 * Preemption must be disabled here before the function
+		 * tracer can trace. Break up preempt_disable() into two
+		 * calls. One to disable preemption without fear of being
+		 * traced. The other to still record the preemption latency,
+		 * which can also be traced by the function tracer.
+		 */
+		preempt_disable_notrace();
+		preempt_latency_start(1);
+		__schedule(true);
+		preempt_latency_stop(1);
+		preempt_enable_no_resched_notrace();
+
+		/*
+		 * Check again in case we missed a preemption opportunity
+		 * between schedule and now.
+		 */
+	} while (need_resched());
+}
+
+#ifdef CONFIG_PREEMPTION
+/*
+ * This is the entry point to schedule() from in-kernel preemption
+ * off of preempt_enable.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule(void)
+{
+	/*
+	 * If there is a non-zero preempt_count or interrupts are disabled,
+	 * we do not want to preempt the current task. Just return..
+	 */
+	if (likely(!preemptible()))
+		return;
+
+	preempt_schedule_common();
+}
+NOKPROBE_SYMBOL(preempt_schedule);
+EXPORT_SYMBOL(preempt_schedule);
+
+/**
+ * preempt_schedule_notrace - preempt_schedule called by tracing
+ *
+ * The tracing infrastructure uses preempt_enable_notrace to prevent
+ * recursion and tracing preempt enabling caused by the tracing
+ * infrastructure itself. But as tracing can happen in areas coming
+ * from userspace or just about to enter userspace, a preempt enable
+ * can occur before user_exit() is called. This will cause the scheduler
+ * to be called when the system is still in usermode.
+ *
+ * To prevent this, the preempt_enable_notrace will use this function
+ * instead of preempt_schedule() to exit user context if needed before
+ * calling the scheduler.
+ */
+asmlinkage __visible void __sched notrace preempt_schedule_notrace(void)
+{
+	enum ctx_state prev_ctx;
+
+	if (likely(!preemptible()))
+		return;
+
+	do {
+		/*
+		 * Because the function tracer can trace preempt_count_sub()
+		 * and it also uses preempt_enable/disable_notrace(), if
+		 * NEED_RESCHED is set, the preempt_enable_notrace() called
+		 * by the function tracer will call this function again and
+		 * cause infinite recursion.
+		 *
+		 * Preemption must be disabled here before the function
+		 * tracer can trace. Break up preempt_disable() into two
+		 * calls. One to disable preemption without fear of being
+		 * traced. The other to still record the preemption latency,
+		 * which can also be traced by the function tracer.
+		 */
+		preempt_disable_notrace();
+		preempt_latency_start(1);
+		/*
+		 * Needs preempt disabled in case user_exit() is traced
+		 * and the tracer calls preempt_enable_notrace() causing
+		 * an infinite recursion.
+		 */
+		prev_ctx = exception_enter();
+		__schedule(true);
+		exception_exit(prev_ctx);
+
+		preempt_latency_stop(1);
+		preempt_enable_no_resched_notrace();
+	} while (need_resched());
+}
+EXPORT_SYMBOL_GPL(preempt_schedule_notrace);
+
+#endif /* CONFIG_PREEMPTION */
+
+/*
+ * This is the entry point to schedule() from kernel preemption
+ * off of irq context.
+ * Note, that this is called and return with irqs disabled. This will
+ * protect us against recursive calling from irq.
+ */
+asmlinkage __visible void __sched preempt_schedule_irq(void)
+{
+	enum ctx_state prev_state;
+
+	/* Catch callers which need to be fixed */
+	BUG_ON(preempt_count() || !irqs_disabled());
+
+	prev_state = exception_enter();
+
+	do {
+		preempt_disable();
+		local_irq_enable();
+		__schedule(true);
+		local_irq_disable();
+		sched_preempt_enable_no_resched();
+	} while (need_resched());
+
+	exception_exit(prev_state);
+}
+
+int default_wake_function(wait_queue_entry_t *curr, unsigned mode, int wake_flags,
+			  void *key)
+{
+	WARN_ON_ONCE(IS_ENABLED(CONFIG_SCHED_DEBUG) && wake_flags & ~WF_SYNC);
+	return try_to_wake_up(curr->private, mode, wake_flags);
+}
+EXPORT_SYMBOL(default_wake_function);
+
+static inline void check_task_changed(struct rq *rq, struct task_struct *p)
+{
+	/* Trigger resched if task sched_prio has been modified. */
+	if (task_on_rq_queued(p) && sched_task_need_requeue(p, rq)) {
+		requeue_task(p, rq);
+		check_preempt_curr(rq);
+	}
+}
+
+#ifdef CONFIG_RT_MUTEXES
+
+static inline int __rt_effective_prio(struct task_struct *pi_task, int prio)
+{
+	if (pi_task)
+		prio = min(prio, pi_task->prio);
+
+	return prio;
+}
+
+static inline int rt_effective_prio(struct task_struct *p, int prio)
+{
+	struct task_struct *pi_task = rt_mutex_get_top_task(p);
+
+	return __rt_effective_prio(pi_task, prio);
+}
+
+/*
+ * rt_mutex_setprio - set the current priority of a task
+ * @p: task to boost
+ * @pi_task: donor task
+ *
+ * This function changes the 'effective' priority of a task. It does
+ * not touch ->normal_prio like __setscheduler().
+ *
+ * Used by the rt_mutex code to implement priority inheritance
+ * logic. Call site only calls if the priority of the task changed.
+ */
+void rt_mutex_setprio(struct task_struct *p, struct task_struct *pi_task)
+{
+	int prio;
+	struct rq *rq;
+	raw_spinlock_t *lock;
+
+	/* XXX used to be waiter->prio, not waiter->task->prio */
+	prio = __rt_effective_prio(pi_task, p->normal_prio);
+
+	/*
+	 * If nothing changed; bail early.
+	 */
+	if (p->pi_top_task == pi_task && prio == p->prio)
+		return;
+
+	rq = __task_access_lock(p, &lock);
+	/*
+	 * Set under pi_lock && rq->lock, such that the value can be used under
+	 * either lock.
+	 *
+	 * Note that there is loads of tricky to make this pointer cache work
+	 * right. rt_mutex_slowunlock()+rt_mutex_postunlock() work together to
+	 * ensure a task is de-boosted (pi_task is set to NULL) before the
+	 * task is allowed to run again (and can exit). This ensures the pointer
+	 * points to a blocked task -- which guaratees the task is present.
+	 */
+	p->pi_top_task = pi_task;
+
+	/*
+	 * For FIFO/RR we only need to set prio, if that matches we're done.
+	 */
+	if (prio == p->prio)
+		goto out_unlock;
+
+	/*
+	 * Idle task boosting is a nono in general. There is one
+	 * exception, when PREEMPT_RT and NOHZ is active:
+	 *
+	 * The idle task calls get_next_timer_interrupt() and holds
+	 * the timer wheel base->lock on the CPU and another CPU wants
+	 * to access the timer (probably to cancel it). We can safely
+	 * ignore the boosting request, as the idle CPU runs this code
+	 * with interrupts disabled and will complete the lock
+	 * protected section without being interrupted. So there is no
+	 * real need to boost.
+	 */
+	if (unlikely(p == rq->idle)) {
+		WARN_ON(p != rq->curr);
+		WARN_ON(p->pi_blocked_on);
+		goto out_unlock;
+	}
+
+	trace_sched_pi_setprio(p, pi_task);
+	p->prio = prio;
+	update_task_priodl(p);
+
+	check_task_changed(rq, p);
+out_unlock:
+	__task_access_unlock(p, lock);
+}
+#else
+static inline int rt_effective_prio(struct task_struct *p, int prio)
+{
+	return prio;
+}
+#endif
+
+void set_user_nice(struct task_struct *p, long nice)
+{
+	unsigned long flags;
+	struct rq *rq;
+	raw_spinlock_t *lock;
+
+	if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE)
+		return;
+	/*
+	 * We have to be careful, if called from sys_setpriority(),
+	 * the task might be in the middle of scheduling on another CPU.
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+	rq = __task_access_lock(p, &lock);
+
+	p->static_prio = NICE_TO_PRIO(nice);
+	/*
+	 * The RT priorities are set via sched_setscheduler(), but we still
+	 * allow the 'normal' nice value to be set - but as expected
+	 * it wont have any effect on scheduling until the task is
+	 * not SCHED_NORMAL/SCHED_BATCH:
+	 */
+	if (task_has_rt_policy(p))
+		goto out_unlock;
+
+	p->prio = effective_prio(p);
+	update_task_priodl(p);
+
+	check_task_changed(rq, p);
+out_unlock:
+	__task_access_unlock(p, lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+}
+EXPORT_SYMBOL(set_user_nice);
+
+/*
+ * can_nice - check if a task can reduce its nice value
+ * @p: task
+ * @nice: nice value
+ */
+int can_nice(const struct task_struct *p, const int nice)
+{
+	/* Convert nice value [19,-20] to rlimit style value [1,40] */
+	int nice_rlim = nice_to_rlimit(nice);
+
+	return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) ||
+		capable(CAP_SYS_NICE));
+}
+
+#ifdef __ARCH_WANT_SYS_NICE
+
+/*
+ * sys_nice - change the priority of the current process.
+ * @increment: priority increment
+ *
+ * sys_setpriority is a more generic, but much slower function that
+ * does similar things.
+ */
+SYSCALL_DEFINE1(nice, int, increment)
+{
+	long nice, retval;
+
+	/*
+	 * Setpriority might change our priority at the same moment.
+	 * We don't have to worry. Conceptually one call occurs first
+	 * and we have a single winner.
+	 */
+
+	increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH);
+	nice = task_nice(current) + increment;
+
+	nice = clamp_val(nice, MIN_NICE, MAX_NICE);
+	if (increment < 0 && !can_nice(current, nice))
+		return -EPERM;
+
+	retval = security_task_setnice(current, nice);
+	if (retval)
+		return retval;
+
+	set_user_nice(current, nice);
+	return 0;
+}
+
+#endif
+
+/**
+ * idle_cpu - is a given CPU idle currently?
+ * @cpu: the processor in question.
+ *
+ * Return: 1 if the CPU is currently idle. 0 otherwise.
+ */
+int idle_cpu(int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	if (rq->curr != rq->idle)
+		return 0;
+
+	if (rq->nr_running)
+		return 0;
+
+#ifdef CONFIG_SMP
+	if (rq->ttwu_pending)
+		return 0;
+#endif
+
+	return 1;
+}
+
+/**
+ * idle_task - return the idle task for a given CPU.
+ * @cpu: the processor in question.
+ *
+ * Return: The idle task for the cpu @cpu.
+ */
+struct task_struct *idle_task(int cpu)
+{
+	return cpu_rq(cpu)->idle;
+}
+
+/**
+ * find_process_by_pid - find a process with a matching PID value.
+ * @pid: the pid in question.
+ *
+ * The task of @pid, if found. %NULL otherwise.
+ */
+static inline struct task_struct *find_process_by_pid(pid_t pid)
+{
+	return pid ? find_task_by_vpid(pid) : current;
+}
+
+/*
+ * sched_setparam() passes in -1 for its policy, to let the functions
+ * it calls know not to change it.
+ */
+#define SETPARAM_POLICY -1
+
+static void __setscheduler_params(struct task_struct *p,
+		const struct sched_attr *attr)
+{
+	int policy = attr->sched_policy;
+
+	if (policy == SETPARAM_POLICY)
+		policy = p->policy;
+
+	p->policy = policy;
+
+	/*
+	 * allow normal nice value to be set, but will not have any
+	 * effect on scheduling until the task not SCHED_NORMAL/
+	 * SCHED_BATCH
+	 */
+	p->static_prio = NICE_TO_PRIO(attr->sched_nice);
+
+	/*
+	 * __sched_setscheduler() ensures attr->sched_priority == 0 when
+	 * !rt_policy. Always setting this ensures that things like
+	 * getparam()/getattr() don't report silly values for !rt tasks.
+	 */
+	p->rt_priority = attr->sched_priority;
+	p->normal_prio = normal_prio(p);
+}
+
+/* Actually do priority change: must hold rq lock. */
+static void __setscheduler(struct rq *rq, struct task_struct *p,
+			   const struct sched_attr *attr, bool keep_boost)
+{
+	__setscheduler_params(p, attr);
+
+	/*
+	 * Keep a potential priority boosting if called from
+	 * sched_setscheduler().
+	 */
+	p->prio = normal_prio(p);
+	if (keep_boost)
+		p->prio = rt_effective_prio(p, p->prio);
+	update_task_priodl(p);
+}
+
+/*
+ * check the target process has a UID that matches the current process's
+ */
+static bool check_same_owner(struct task_struct *p)
+{
+	const struct cred *cred = current_cred(), *pcred;
+	bool match;
+
+	rcu_read_lock();
+	pcred = __task_cred(p);
+	match = (uid_eq(cred->euid, pcred->euid) ||
+		 uid_eq(cred->euid, pcred->uid));
+	rcu_read_unlock();
+	return match;
+}
+
+static int __sched_setscheduler(struct task_struct *p,
+				const struct sched_attr *attr,
+				bool user, bool pi)
+{
+	const struct sched_attr dl_squash_attr = {
+		.size		= sizeof(struct sched_attr),
+		.sched_policy	= SCHED_FIFO,
+		.sched_nice	= 0,
+		.sched_priority = 99,
+	};
+	int newprio = MAX_RT_PRIO - 1 - attr->sched_priority;
+	int retval, oldpolicy = -1;
+	int policy = attr->sched_policy;
+	unsigned long flags;
+	struct rq *rq;
+	int reset_on_fork;
+	raw_spinlock_t *lock;
+
+	/* The pi code expects interrupts enabled */
+	BUG_ON(pi && in_interrupt());
+
+	/*
+	 * Alt schedule FW supports SCHED_DEADLINE by squash it as prio 0 SCHED_FIFO
+	 */
+	if (unlikely(SCHED_DEADLINE == policy)) {
+		attr = &dl_squash_attr;
+		policy = attr->sched_policy;
+		newprio = MAX_RT_PRIO - 1 - attr->sched_priority;
+	}
+recheck:
+	/* Double check policy once rq lock held */
+	if (policy < 0) {
+		reset_on_fork = p->sched_reset_on_fork;
+		policy = oldpolicy = p->policy;
+	} else {
+		reset_on_fork = !!(attr->sched_flags & SCHED_RESET_ON_FORK);
+
+		if (policy > SCHED_IDLE)
+			return -EINVAL;
+	}
+
+	if (attr->sched_flags & ~(SCHED_FLAG_ALL))
+		return -EINVAL;
+
+	/*
+	 * Valid priorities for SCHED_FIFO and SCHED_RR are
+	 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and
+	 * SCHED_BATCH and SCHED_IDLE is 0.
+	 */
+	if (attr->sched_priority < 0 ||
+	    (p->mm && attr->sched_priority > MAX_USER_RT_PRIO - 1) ||
+	    (!p->mm && attr->sched_priority > MAX_RT_PRIO - 1))
+		return -EINVAL;
+	if ((SCHED_RR == policy || SCHED_FIFO == policy) !=
+	    (attr->sched_priority != 0))
+		return -EINVAL;
+
+	/*
+	 * Allow unprivileged RT tasks to decrease priority:
+	 */
+	if (user && !capable(CAP_SYS_NICE)) {
+		if (SCHED_FIFO == policy || SCHED_RR == policy) {
+			unsigned long rlim_rtprio =
+					task_rlimit(p, RLIMIT_RTPRIO);
+
+			/* Can't set/change the rt policy */
+			if (policy != p->policy && !rlim_rtprio)
+				return -EPERM;
+
+			/* Can't increase priority */
+			if (attr->sched_priority > p->rt_priority &&
+			    attr->sched_priority > rlim_rtprio)
+				return -EPERM;
+		}
+
+		/* Can't change other user's priorities */
+		if (!check_same_owner(p))
+			return -EPERM;
+
+		/* Normal users shall not reset the sched_reset_on_fork flag */
+		if (p->sched_reset_on_fork && !reset_on_fork)
+			return -EPERM;
+	}
+
+	if (user) {
+		retval = security_task_setscheduler(p);
+		if (retval)
+			return retval;
+	}
+
+	if (pi)
+		cpuset_read_lock();
+
+	/*
+	 * Make sure no PI-waiters arrive (or leave) while we are
+	 * changing the priority of the task:
+	 */
+	raw_spin_lock_irqsave(&p->pi_lock, flags);
+
+	/*
+	 * To be able to change p->policy safely, task_access_lock()
+	 * must be called.
+	 * IF use task_access_lock() here:
+	 * For the task p which is not running, reading rq->stop is
+	 * racy but acceptable as ->stop doesn't change much.
+	 * An enhancemnet can be made to read rq->stop saftly.
+	 */
+	rq = __task_access_lock(p, &lock);
+
+	/*
+	 * Changing the policy of the stop threads its a very bad idea
+	 */
+	if (p == rq->stop) {
+		retval = -EINVAL;
+		goto unlock;
+	}
+
+	/*
+	 * If not changing anything there's no need to proceed further:
+	 */
+	if (unlikely(policy == p->policy)) {
+		if (rt_policy(policy) && attr->sched_priority != p->rt_priority)
+			goto change;
+		if (!rt_policy(policy) &&
+		    NICE_TO_PRIO(attr->sched_nice) != p->static_prio)
+			goto change;
+
+		p->sched_reset_on_fork = reset_on_fork;
+		retval = 0;
+		goto unlock;
+	}
+change:
+
+	/* Re-check policy now with rq lock held */
+	if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
+		policy = oldpolicy = -1;
+		__task_access_unlock(p, lock);
+		raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+		if (pi)
+			cpuset_read_unlock();
+		goto recheck;
+	}
+
+	p->sched_reset_on_fork = reset_on_fork;
+
+	if (pi) {
+		/*
+		 * Take priority boosted tasks into account. If the new
+		 * effective priority is unchanged, we just store the new
+		 * normal parameters and do not touch the scheduler class and
+		 * the runqueue. This will be done when the task deboost
+		 * itself.
+		 */
+		if (rt_effective_prio(p, newprio) == p->prio) {
+			__setscheduler_params(p, attr);
+			retval = 0;
+			goto unlock;
+		}
+	}
+
+	__setscheduler(rq, p, attr, pi);
+
+	check_task_changed(rq, p);
+
+	/* Avoid rq from going away on us: */
+	preempt_disable();
+	__task_access_unlock(p, lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+
+	if (pi) {
+		cpuset_read_unlock();
+		rt_mutex_adjust_pi(p);
+	}
+
+	preempt_enable();
+
+	return 0;
+
+unlock:
+	__task_access_unlock(p, lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, flags);
+	if (pi)
+		cpuset_read_unlock();
+	return retval;
+}
+
+static int _sched_setscheduler(struct task_struct *p, int policy,
+			       const struct sched_param *param, bool check)
+{
+	struct sched_attr attr = {
+		.sched_policy   = policy,
+		.sched_priority = param->sched_priority,
+		.sched_nice     = PRIO_TO_NICE(p->static_prio),
+	};
+
+	/* Fixup the legacy SCHED_RESET_ON_FORK hack. */
+	if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) {
+		attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
+		policy &= ~SCHED_RESET_ON_FORK;
+		attr.sched_policy = policy;
+	}
+
+	return __sched_setscheduler(p, &attr, check, true);
+}
+
+/**
+ * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Use sched_set_fifo(), read its comment.
+ *
+ * Return: 0 on success. An error code otherwise.
+ *
+ * NOTE that the task may be already dead.
+ */
+int sched_setscheduler(struct task_struct *p, int policy,
+		       const struct sched_param *param)
+{
+	return _sched_setscheduler(p, policy, param, true);
+}
+
+int sched_setattr(struct task_struct *p, const struct sched_attr *attr)
+{
+	return __sched_setscheduler(p, attr, true, true);
+}
+
+int sched_setattr_nocheck(struct task_struct *p, const struct sched_attr *attr)
+{
+	return __sched_setscheduler(p, attr, false, true);
+}
+
+/**
+ * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace.
+ * @p: the task in question.
+ * @policy: new policy.
+ * @param: structure containing the new RT priority.
+ *
+ * Just like sched_setscheduler, only don't bother checking if the
+ * current context has permission.  For example, this is needed in
+ * stop_machine(): we create temporary high priority worker threads,
+ * but our caller might not have that capability.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+int sched_setscheduler_nocheck(struct task_struct *p, int policy,
+			       const struct sched_param *param)
+{
+	return _sched_setscheduler(p, policy, param, false);
+}
+
+/*
+ * SCHED_FIFO is a broken scheduler model; that is, it is fundamentally
+ * incapable of resource management, which is the one thing an OS really should
+ * be doing.
+ *
+ * This is of course the reason it is limited to privileged users only.
+ *
+ * Worse still; it is fundamentally impossible to compose static priority
+ * workloads. You cannot take two correctly working static prio workloads
+ * and smash them together and still expect them to work.
+ *
+ * For this reason 'all' FIFO tasks the kernel creates are basically at:
+ *
+ *   MAX_RT_PRIO / 2
+ *
+ * The administrator _MUST_ configure the system, the kernel simply doesn't
+ * know enough information to make a sensible choice.
+ */
+void sched_set_fifo(struct task_struct *p)
+{
+	struct sched_param sp = { .sched_priority = MAX_RT_PRIO / 2 };
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_fifo);
+
+/*
+ * For when you don't much care about FIFO, but want to be above SCHED_NORMAL.
+ */
+void sched_set_fifo_low(struct task_struct *p)
+{
+	struct sched_param sp = { .sched_priority = 1 };
+	WARN_ON_ONCE(sched_setscheduler_nocheck(p, SCHED_FIFO, &sp) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_fifo_low);
+
+void sched_set_normal(struct task_struct *p, int nice)
+{
+	struct sched_attr attr = {
+		.sched_policy = SCHED_NORMAL,
+		.sched_nice = nice,
+	};
+	WARN_ON_ONCE(sched_setattr_nocheck(p, &attr) != 0);
+}
+EXPORT_SYMBOL_GPL(sched_set_normal);
+
+static int
+do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
+{
+	struct sched_param lparam;
+	struct task_struct *p;
+	int retval;
+
+	if (!param || pid < 0)
+		return -EINVAL;
+	if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
+		return -EFAULT;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (likely(p))
+		get_task_struct(p);
+	rcu_read_unlock();
+
+	if (likely(p)) {
+		retval = sched_setscheduler(p, policy, &lparam);
+		put_task_struct(p);
+	}
+
+	return retval;
+}
+
+/*
+ * Mimics kernel/events/core.c perf_copy_attr().
+ */
+static int sched_copy_attr(struct sched_attr __user *uattr, struct sched_attr *attr)
+{
+	u32 size;
+	int ret;
+
+	/* Zero the full structure, so that a short copy will be nice: */
+	memset(attr, 0, sizeof(*attr));
+
+	ret = get_user(size, &uattr->size);
+	if (ret)
+		return ret;
+
+	/* ABI compatibility quirk: */
+	if (!size)
+		size = SCHED_ATTR_SIZE_VER0;
+
+	if (size < SCHED_ATTR_SIZE_VER0 || size > PAGE_SIZE)
+		goto err_size;
+
+	ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
+	if (ret) {
+		if (ret == -E2BIG)
+			goto err_size;
+		return ret;
+	}
+
+	/*
+	 * XXX: Do we want to be lenient like existing syscalls; or do we want
+	 * to be strict and return an error on out-of-bounds values?
+	 */
+	attr->sched_nice = clamp(attr->sched_nice, -20, 19);
+
+	/* sched/core.c uses zero here but we already know ret is zero */
+	return 0;
+
+err_size:
+	put_user(sizeof(*attr), &uattr->size);
+	return -E2BIG;
+}
+
+/**
+ * sys_sched_setscheduler - set/change the scheduler policy and RT priority
+ * @pid: the pid in question.
+ * @policy: new policy.
+ *
+ * Return: 0 on success. An error code otherwise.
+ * @param: structure containing the new RT priority.
+ */
+SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, struct sched_param __user *, param)
+{
+	if (policy < 0)
+		return -EINVAL;
+
+	return do_sched_setscheduler(pid, policy, param);
+}
+
+/**
+ * sys_sched_setparam - set/change the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the new RT priority.
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
+{
+	return do_sched_setscheduler(pid, SETPARAM_POLICY, param);
+}
+
+/**
+ * sys_sched_setattr - same as above, but with extended sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ */
+SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
+			       unsigned int, flags)
+{
+	struct sched_attr attr;
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || flags)
+		return -EINVAL;
+
+	retval = sched_copy_attr(uattr, &attr);
+	if (retval)
+		return retval;
+
+	if ((int)attr.sched_policy < 0)
+		return -EINVAL;
+
+	rcu_read_lock();
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (p != NULL)
+		retval = sched_setattr(p, &attr);
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the policy (scheduling class) of a thread
+ * @pid: the pid in question.
+ *
+ * Return: On success, the policy of the thread. Otherwise, a negative error
+ * code.
+ */
+SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid)
+{
+	struct task_struct *p;
+	int retval = -EINVAL;
+
+	if (pid < 0)
+		goto out_nounlock;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (p) {
+		retval = security_task_getscheduler(p);
+		if (!retval)
+			retval = p->policy;
+	}
+	rcu_read_unlock();
+
+out_nounlock:
+	return retval;
+}
+
+/**
+ * sys_sched_getscheduler - get the RT priority of a thread
+ * @pid: the pid in question.
+ * @param: structure containing the RT priority.
+ *
+ * Return: On success, 0 and the RT priority is in @param. Otherwise, an error
+ * code.
+ */
+SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
+{
+	struct sched_param lp = { .sched_priority = 0 };
+	struct task_struct *p;
+	int retval = -EINVAL;
+
+	if (!param || pid < 0)
+		goto out_nounlock;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	if (task_has_rt_policy(p))
+		lp.sched_priority = p->rt_priority;
+	rcu_read_unlock();
+
+	/*
+	 * This one might sleep, we cannot do it with a spinlock held ...
+	 */
+	retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
+
+out_nounlock:
+	return retval;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+/*
+ * Copy the kernel size attribute structure (which might be larger
+ * than what user-space knows about) to user-space.
+ *
+ * Note that all cases are valid: user-space buffer can be larger or
+ * smaller than the kernel-space buffer. The usual case is that both
+ * have the same size.
+ */
+static int
+sched_attr_copy_to_user(struct sched_attr __user *uattr,
+			struct sched_attr *kattr,
+			unsigned int usize)
+{
+	unsigned int ksize = sizeof(*kattr);
+
+	if (!access_ok(uattr, usize))
+		return -EFAULT;
+
+	/*
+	 * sched_getattr() ABI forwards and backwards compatibility:
+	 *
+	 * If usize == ksize then we just copy everything to user-space and all is good.
+	 *
+	 * If usize < ksize then we only copy as much as user-space has space for,
+	 * this keeps ABI compatibility as well. We skip the rest.
+	 *
+	 * If usize > ksize then user-space is using a newer version of the ABI,
+	 * which part the kernel doesn't know about. Just ignore it - tooling can
+	 * detect the kernel's knowledge of attributes from the attr->size value
+	 * which is set to ksize in this case.
+	 */
+	kattr->size = min(usize, ksize);
+
+	if (copy_to_user(uattr, kattr, kattr->size))
+		return -EFAULT;
+
+	return 0;
+}
+
+/**
+ * sys_sched_getattr - similar to sched_getparam, but with sched_attr
+ * @pid: the pid in question.
+ * @uattr: structure containing the extended parameters.
+ * @usize: sizeof(attr) for fwd/bwd comp.
+ * @flags: for future extension.
+ */
+SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr,
+		unsigned int, usize, unsigned int, flags)
+{
+	struct sched_attr kattr = { };
+	struct task_struct *p;
+	int retval;
+
+	if (!uattr || pid < 0 || usize > PAGE_SIZE ||
+	    usize < SCHED_ATTR_SIZE_VER0 || flags)
+		return -EINVAL;
+
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	retval = -ESRCH;
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	kattr.sched_policy = p->policy;
+	if (p->sched_reset_on_fork)
+		kattr.sched_flags |= SCHED_FLAG_RESET_ON_FORK;
+	if (task_has_rt_policy(p))
+		kattr.sched_priority = p->rt_priority;
+	else
+		kattr.sched_nice = task_nice(p);
+
+#ifdef CONFIG_UCLAMP_TASK
+	kattr.sched_util_min = p->uclamp_req[UCLAMP_MIN].value;
+	kattr.sched_util_max = p->uclamp_req[UCLAMP_MAX].value;
+#endif
+
+	rcu_read_unlock();
+
+	return sched_attr_copy_to_user(uattr, &kattr, usize);
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+long sched_setaffinity(pid_t pid, const struct cpumask *in_mask)
+{
+	cpumask_var_t cpus_allowed, new_mask;
+	struct task_struct *p;
+	int retval;
+
+	get_online_cpus();
+	rcu_read_lock();
+
+	p = find_process_by_pid(pid);
+	if (!p) {
+		rcu_read_unlock();
+		put_online_cpus();
+		return -ESRCH;
+	}
+
+	/* Prevent p going away */
+	get_task_struct(p);
+	rcu_read_unlock();
+
+	if (p->flags & PF_NO_SETAFFINITY) {
+		retval = -EINVAL;
+		goto out_put_task;
+	}
+	if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_put_task;
+	}
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) {
+		retval = -ENOMEM;
+		goto out_free_cpus_allowed;
+	}
+	retval = -EPERM;
+	if (!check_same_owner(p)) {
+		rcu_read_lock();
+		if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) {
+			rcu_read_unlock();
+			goto out_unlock;
+		}
+		rcu_read_unlock();
+	}
+
+	retval = security_task_setscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	cpuset_cpus_allowed(p, cpus_allowed);
+	cpumask_and(new_mask, in_mask, cpus_allowed);
+again:
+	retval = __set_cpus_allowed_ptr(p, new_mask, true);
+
+	if (!retval) {
+		cpuset_cpus_allowed(p, cpus_allowed);
+		if (!cpumask_subset(new_mask, cpus_allowed)) {
+			/*
+			 * We must have raced with a concurrent cpuset
+			 * update. Just reset the cpus_allowed to the
+			 * cpuset's cpus_allowed
+			 */
+			cpumask_copy(new_mask, cpus_allowed);
+			goto again;
+		}
+	}
+out_unlock:
+	free_cpumask_var(new_mask);
+out_free_cpus_allowed:
+	free_cpumask_var(cpus_allowed);
+out_put_task:
+	put_task_struct(p);
+	put_online_cpus();
+	return retval;
+}
+
+static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
+			     struct cpumask *new_mask)
+{
+	if (len < cpumask_size())
+		cpumask_clear(new_mask);
+	else if (len > cpumask_size())
+		len = cpumask_size();
+
+	return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
+}
+
+/**
+ * sys_sched_setaffinity - set the CPU affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to the new CPU mask
+ *
+ * Return: 0 on success. An error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	cpumask_var_t new_mask;
+	int retval;
+
+	if (!alloc_cpumask_var(&new_mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	retval = get_user_cpu_mask(user_mask_ptr, len, new_mask);
+	if (retval == 0)
+		retval = sched_setaffinity(pid, new_mask);
+	free_cpumask_var(new_mask);
+	return retval;
+}
+
+long sched_getaffinity(pid_t pid, cpumask_t *mask)
+{
+	struct task_struct *p;
+	raw_spinlock_t *lock;
+	unsigned long flags;
+	int retval;
+
+	rcu_read_lock();
+
+	retval = -ESRCH;
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+
+	task_access_lock_irqsave(p, &lock, &flags);
+	cpumask_and(mask, &p->cpus_mask, cpu_active_mask);
+	task_access_unlock_irqrestore(p, lock, &flags);
+
+out_unlock:
+	rcu_read_unlock();
+
+	return retval;
+}
+
+/**
+ * sys_sched_getaffinity - get the CPU affinity of a process
+ * @pid: pid of the process
+ * @len: length in bytes of the bitmask pointed to by user_mask_ptr
+ * @user_mask_ptr: user-space pointer to hold the current CPU mask
+ *
+ * Return: size of CPU mask copied to user_mask_ptr on success. An
+ * error code otherwise.
+ */
+SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len,
+		unsigned long __user *, user_mask_ptr)
+{
+	int ret;
+	cpumask_var_t mask;
+
+	if ((len * BITS_PER_BYTE) < nr_cpu_ids)
+		return -EINVAL;
+	if (len & (sizeof(unsigned long)-1))
+		return -EINVAL;
+
+	if (!alloc_cpumask_var(&mask, GFP_KERNEL))
+		return -ENOMEM;
+
+	ret = sched_getaffinity(pid, mask);
+	if (ret == 0) {
+		unsigned int retlen = min_t(size_t, len, cpumask_size());
+
+		if (copy_to_user(user_mask_ptr, mask, retlen))
+			ret = -EFAULT;
+		else
+			ret = retlen;
+	}
+	free_cpumask_var(mask);
+
+	return ret;
+}
+
+/**
+ * sys_sched_yield - yield the current processor to other threads.
+ *
+ * This function yields the current CPU to other tasks. It does this by
+ * scheduling away the current task. If it still has the earliest deadline
+ * it will be scheduled again as the next task.
+ *
+ * Return: 0.
+ */
+static void do_sched_yield(void)
+{
+	struct rq *rq;
+	struct rq_flags rf;
+
+	if (!sched_yield_type)
+		return;
+
+	rq = this_rq_lock_irq(&rf);
+
+	schedstat_inc(rq->yld_count);
+
+	if (1 == sched_yield_type) {
+		if (!rt_task(current))
+			do_sched_yield_type_1(current, rq);
+	} else if (2 == sched_yield_type) {
+		if (rq->nr_running > 1)
+			rq->skip = current;
+	}
+
+	/*
+	 * Since we are going to call schedule() anyway, there's
+	 * no need to preempt or enable interrupts:
+	 */
+	preempt_disable();
+	raw_spin_unlock(&rq->lock);
+	sched_preempt_enable_no_resched();
+
+	schedule();
+}
+
+SYSCALL_DEFINE0(sched_yield)
+{
+	do_sched_yield();
+	return 0;
+}
+
+#ifndef CONFIG_PREEMPTION
+int __sched _cond_resched(void)
+{
+	if (should_resched(0)) {
+		preempt_schedule_common();
+		return 1;
+	}
+	rcu_all_qs();
+	return 0;
+}
+EXPORT_SYMBOL(_cond_resched);
+#endif
+
+/*
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * call schedule, and on return reacquire the lock.
+ *
+ * This works OK both with and without CONFIG_PREEMPTION.  We do strange low-level
+ * operations here to prevent schedule() from being called twice (once via
+ * spin_unlock(), once by hand).
+ */
+int __cond_resched_lock(spinlock_t *lock)
+{
+	int resched = should_resched(PREEMPT_LOCK_OFFSET);
+	int ret = 0;
+
+	lockdep_assert_held(lock);
+
+	if (spin_needbreak(lock) || resched) {
+		spin_unlock(lock);
+		if (resched)
+			preempt_schedule_common();
+		else
+			cpu_relax();
+		ret = 1;
+		spin_lock(lock);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(__cond_resched_lock);
+
+/**
+ * yield - yield the current processor to other threads.
+ *
+ * Do not ever use this function, there's a 99% chance you're doing it wrong.
+ *
+ * The scheduler is at all times free to pick the calling task as the most
+ * eligible task to run, if removing the yield() call from your code breaks
+ * it, its already broken.
+ *
+ * Typical broken usage is:
+ *
+ * while (!event)
+ * 	yield();
+ *
+ * where one assumes that yield() will let 'the other' process run that will
+ * make event true. If the current task is a SCHED_FIFO task that will never
+ * happen. Never use yield() as a progress guarantee!!
+ *
+ * If you want to use yield() to wait for something, use wait_event().
+ * If you want to use yield() to be 'nice' for others, use cond_resched().
+ * If you still want to use yield(), do not!
+ */
+void __sched yield(void)
+{
+	set_current_state(TASK_RUNNING);
+	do_sched_yield();
+}
+EXPORT_SYMBOL(yield);
+
+/**
+ * yield_to - yield the current processor to another thread in
+ * your thread group, or accelerate that thread toward the
+ * processor it's on.
+ * @p: target task
+ * @preempt: whether task preemption is allowed or not
+ *
+ * It's the caller's job to ensure that the target task struct
+ * can't go away on us before we can do any checks.
+ *
+ * In Alt schedule FW, yield_to is not supported.
+ *
+ * Return:
+ *	true (>0) if we indeed boosted the target task.
+ *	false (0) if we failed to boost the target.
+ *	-ESRCH if there's no task to yield to.
+ */
+int __sched yield_to(struct task_struct *p, bool preempt)
+{
+	return 0;
+}
+EXPORT_SYMBOL_GPL(yield_to);
+
+int io_schedule_prepare(void)
+{
+	int old_iowait = current->in_iowait;
+
+	current->in_iowait = 1;
+	blk_schedule_flush_plug(current);
+
+	return old_iowait;
+}
+
+void io_schedule_finish(int token)
+{
+	current->in_iowait = token;
+}
+
+/*
+ * This task is about to go to sleep on IO.  Increment rq->nr_iowait so
+ * that process accounting knows that this is a task in IO wait state.
+ *
+ * But don't do that if it is a deliberate, throttling IO wait (this task
+ * has set its backing_dev_info: the queue against which it should throttle)
+ */
+
+long __sched io_schedule_timeout(long timeout)
+{
+	int token;
+	long ret;
+
+	token = io_schedule_prepare();
+	ret = schedule_timeout(timeout);
+	io_schedule_finish(token);
+
+	return ret;
+}
+EXPORT_SYMBOL(io_schedule_timeout);
+
+void __sched io_schedule(void)
+{
+	int token;
+
+	token = io_schedule_prepare();
+	schedule();
+	io_schedule_finish(token);
+}
+EXPORT_SYMBOL(io_schedule);
+
+/**
+ * sys_sched_get_priority_max - return maximum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the maximum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_max, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = MAX_USER_RT_PRIO-1;
+		break;
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+/**
+ * sys_sched_get_priority_min - return minimum RT priority.
+ * @policy: scheduling class.
+ *
+ * Return: On success, this syscall returns the minimum
+ * rt_priority that can be used by a given scheduling class.
+ * On failure, a negative error code is returned.
+ */
+SYSCALL_DEFINE1(sched_get_priority_min, int, policy)
+{
+	int ret = -EINVAL;
+
+	switch (policy) {
+	case SCHED_FIFO:
+	case SCHED_RR:
+		ret = 1;
+		break;
+	case SCHED_NORMAL:
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		ret = 0;
+		break;
+	}
+	return ret;
+}
+
+static int sched_rr_get_interval(pid_t pid, struct timespec64 *t)
+{
+	struct task_struct *p;
+	int retval;
+
+	alt_sched_debug();
+
+	if (pid < 0)
+		return -EINVAL;
+
+	retval = -ESRCH;
+	rcu_read_lock();
+	p = find_process_by_pid(pid);
+	if (!p)
+		goto out_unlock;
+
+	retval = security_task_getscheduler(p);
+	if (retval)
+		goto out_unlock;
+	rcu_read_unlock();
+
+	*t = ns_to_timespec64(sched_timeslice_ns);
+	return 0;
+
+out_unlock:
+	rcu_read_unlock();
+	return retval;
+}
+
+/**
+ * sys_sched_rr_get_interval - return the default timeslice of a process.
+ * @pid: pid of the process.
+ * @interval: userspace pointer to the timeslice value.
+ *
+ *
+ * Return: On success, 0 and the timeslice is in @interval. Otherwise,
+ * an error code.
+ */
+SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
+		struct __kernel_timespec __user *, interval)
+{
+	struct timespec64 t;
+	int retval = sched_rr_get_interval(pid, &t);
+
+	if (retval == 0)
+		retval = put_timespec64(&t, interval);
+
+	return retval;
+}
+
+#ifdef CONFIG_COMPAT_32BIT_TIME
+SYSCALL_DEFINE2(sched_rr_get_interval_time32, pid_t, pid,
+		struct old_timespec32 __user *, interval)
+{
+	struct timespec64 t;
+	int retval = sched_rr_get_interval(pid, &t);
+
+	if (retval == 0)
+		retval = put_old_timespec32(&t, interval);
+	return retval;
+}
+#endif
+
+void sched_show_task(struct task_struct *p)
+{
+	unsigned long free = 0;
+	int ppid;
+
+	if (!try_get_task_stack(p))
+		return;
+
+	pr_info("task:%-15.15s state:%c", p->comm, task_state_to_char(p));
+
+	if (p->state == TASK_RUNNING)
+		pr_cont("  running task    ");
+#ifdef CONFIG_DEBUG_STACK_USAGE
+	free = stack_not_used(p);
+#endif
+	ppid = 0;
+	rcu_read_lock();
+	if (pid_alive(p))
+		ppid = task_pid_nr(rcu_dereference(p->real_parent));
+	rcu_read_unlock();
+	pr_cont(" stack:%5lu pid:%5d ppid:%6d flags:0x%08lx\n",
+		free, task_pid_nr(p), ppid,
+		(unsigned long)task_thread_info(p)->flags);
+
+	print_worker_info(KERN_INFO, p);
+	show_stack(p, NULL, KERN_INFO);
+	put_task_stack(p);
+}
+EXPORT_SYMBOL_GPL(sched_show_task);
+
+static inline bool
+state_filter_match(unsigned long state_filter, struct task_struct *p)
+{
+	/* no filter, everything matches */
+	if (!state_filter)
+		return true;
+
+	/* filter, but doesn't match */
+	if (!(p->state & state_filter))
+		return false;
+
+	/*
+	 * When looking for TASK_UNINTERRUPTIBLE skip TASK_IDLE (allows
+	 * TASK_KILLABLE).
+	 */
+	if (state_filter == TASK_UNINTERRUPTIBLE && p->state == TASK_IDLE)
+		return false;
+
+	return true;
+}
+
+
+void show_state_filter(unsigned long state_filter)
+{
+	struct task_struct *g, *p;
+
+	rcu_read_lock();
+	for_each_process_thread(g, p) {
+		/*
+		 * reset the NMI-timeout, listing all files on a slow
+		 * console might take a lot of time:
+		 * Also, reset softlockup watchdogs on all CPUs, because
+		 * another CPU might be blocked waiting for us to process
+		 * an IPI.
+		 */
+		touch_nmi_watchdog();
+		touch_all_softlockup_watchdogs();
+		if (state_filter_match(state_filter, p))
+			sched_show_task(p);
+	}
+
+#ifdef CONFIG_SCHED_DEBUG
+	/* TODO: Alt schedule FW should support this
+	if (!state_filter)
+		sysrq_sched_debug_show();
+	*/
+#endif
+	rcu_read_unlock();
+	/*
+	 * Only show locks if all tasks are dumped:
+	 */
+	if (!state_filter)
+		debug_show_all_locks();
+}
+
+void dump_cpu_task(int cpu)
+{
+	pr_info("Task dump for CPU %d:\n", cpu);
+	sched_show_task(cpu_curr(cpu));
+}
+
+/**
+ * init_idle - set up an idle thread for a given CPU
+ * @idle: task in question
+ * @cpu: CPU the idle task belongs to
+ *
+ * NOTE: this function does not set the idle thread's NEED_RESCHED
+ * flag, to make booting more robust.
+ */
+void init_idle(struct task_struct *idle, int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	__sched_fork(0, idle);
+
+	raw_spin_lock_irqsave(&idle->pi_lock, flags);
+	raw_spin_lock(&rq->lock);
+	update_rq_clock(rq);
+
+	idle->last_ran = rq->clock_task;
+	idle->state = TASK_RUNNING;
+	idle->flags |= PF_IDLE;
+	sched_queue_init_idle(rq, idle);
+
+	scs_task_reset(idle);
+	kasan_unpoison_task_stack(idle);
+
+#ifdef CONFIG_SMP
+	/*
+	 * It's possible that init_idle() gets called multiple times on a task,
+	 * in that case do_set_cpus_allowed() will not do the right thing.
+	 *
+	 * And since this is boot we can forgo the serialisation.
+	 */
+	set_cpus_allowed_common(idle, cpumask_of(cpu));
+#endif
+
+	/* Silence PROVE_RCU */
+	rcu_read_lock();
+	__set_task_cpu(idle, cpu);
+	rcu_read_unlock();
+
+	rq->idle = idle;
+	rcu_assign_pointer(rq->curr, idle);
+	idle->on_cpu = 1;
+
+	raw_spin_unlock(&rq->lock);
+	raw_spin_unlock_irqrestore(&idle->pi_lock, flags);
+
+	/* Set the preempt count _outside_ the spinlocks! */
+	init_idle_preempt_count(idle, cpu);
+
+	ftrace_graph_init_idle_task(idle, cpu);
+	vtime_init_idle(idle, cpu);
+#ifdef CONFIG_SMP
+	sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
+#endif
+}
+
+#ifdef CONFIG_SMP
+
+int cpuset_cpumask_can_shrink(const struct cpumask __maybe_unused *cur,
+			      const struct cpumask __maybe_unused *trial)
+{
+	return 1;
+}
+
+int task_can_attach(struct task_struct *p,
+		    const struct cpumask *cs_cpus_allowed)
+{
+	int ret = 0;
+
+	/*
+	 * Kthreads which disallow setaffinity shouldn't be moved
+	 * to a new cpuset; we don't want to change their CPU
+	 * affinity and isolating such threads by their set of
+	 * allowed nodes is unnecessary.  Thus, cpusets are not
+	 * applicable for such threads.  This prevents checking for
+	 * success of set_cpus_allowed_ptr() on all attached tasks
+	 * before cpus_mask may be changed.
+	 */
+	if (p->flags & PF_NO_SETAFFINITY)
+		ret = -EINVAL;
+
+	return ret;
+}
+
+bool sched_smp_initialized __read_mostly;
+
+#ifdef CONFIG_HOTPLUG_CPU
+/*
+ * Ensures that the idle task is using init_mm right before its CPU goes
+ * offline.
+ */
+void idle_task_exit(void)
+{
+	struct mm_struct *mm = current->active_mm;
+
+	BUG_ON(current != this_rq()->idle);
+
+	if (mm != &init_mm) {
+		switch_mm(mm, &init_mm, current);
+		finish_arch_post_lock_switch();
+	}
+
+	/* finish_cpu(), as ran on the BP, will clean up the active_mm state */
+}
+
+/*
+ * Migrate all tasks from the rq, sleeping tasks will be migrated by
+ * try_to_wake_up()->select_task_rq().
+ *
+ * Called with rq->lock held even though we'er in stop_machine() and
+ * there's no concurrency possible, we hold the required locks anyway
+ * because of lock validation efforts.
+ */
+static void migrate_tasks(struct rq *dead_rq)
+{
+	struct rq *rq = dead_rq;
+	struct task_struct *p, *stop = rq->stop;
+	int count = 0;
+
+	/*
+	 * Fudge the rq selection such that the below task selection loop
+	 * doesn't get stuck on the currently eligible stop task.
+	 *
+	 * We're currently inside stop_machine() and the rq is either stuck
+	 * in the stop_machine_cpu_stop() loop, or we're executing this code,
+	 * either way we should never end up calling schedule() until we're
+	 * done here.
+	 */
+	rq->stop = NULL;
+
+	p = sched_rq_first_task(rq);
+	while (p != rq->idle) {
+		int dest_cpu;
+
+		/* skip the running task */
+		if (task_running(p) || 1 == p->nr_cpus_allowed) {
+			p = sched_rq_next_task(p, rq);
+			continue;
+		}
+
+		/*
+		 * Rules for changing task_struct::cpus_allowed are holding
+		 * both pi_lock and rq->lock, such that holding either
+		 * stabilizes the mask.
+		 *
+		 * Drop rq->lock is not quite as disastrous as it usually is
+		 * because !cpu_active at this point, which means load-balance
+		 * will not interfere. Also, stop-machine.
+		 */
+		raw_spin_unlock(&rq->lock);
+		raw_spin_lock(&p->pi_lock);
+		raw_spin_lock(&rq->lock);
+
+		/*
+		 * Since we're inside stop-machine, _nothing_ should have
+		 * changed the task, WARN if weird stuff happened, because in
+		 * that case the above rq->lock drop is a fail too.
+		 */
+		if (WARN_ON(task_rq(p) != rq || !task_on_rq_queued(p))) {
+			raw_spin_unlock(&p->pi_lock);
+			p = sched_rq_next_task(p, rq);
+			continue;
+		}
+
+		count++;
+		/* Find suitable destination for @next, with force if needed. */
+		dest_cpu = select_fallback_rq(dead_rq->cpu, p);
+		rq = __migrate_task(rq, p, dest_cpu);
+		raw_spin_unlock(&rq->lock);
+		raw_spin_unlock(&p->pi_lock);
+
+		rq = dead_rq;
+		raw_spin_lock(&rq->lock);
+		/* Check queued task all over from the header again */
+		p = sched_rq_first_task(rq);
+	}
+
+	rq->stop = stop;
+}
+
+static void set_rq_offline(struct rq *rq)
+{
+	if (rq->online)
+		rq->online = false;
+}
+#endif /* CONFIG_HOTPLUG_CPU */
+
+static void set_rq_online(struct rq *rq)
+{
+	if (!rq->online)
+		rq->online = true;
+}
+
+/*
+ * used to mark begin/end of suspend/resume:
+ */
+static int num_cpus_frozen;
+
+/*
+ * Update cpusets according to cpu_active mask.  If cpusets are
+ * disabled, cpuset_update_active_cpus() becomes a simple wrapper
+ * around partition_sched_domains().
+ *
+ * If we come here as part of a suspend/resume, don't touch cpusets because we
+ * want to restore it back to its original state upon resume anyway.
+ */
+static void cpuset_cpu_active(void)
+{
+	if (cpuhp_tasks_frozen) {
+		/*
+		 * num_cpus_frozen tracks how many CPUs are involved in suspend
+		 * resume sequence. As long as this is not the last online
+		 * operation in the resume sequence, just build a single sched
+		 * domain, ignoring cpusets.
+		 */
+		partition_sched_domains(1, NULL, NULL);
+		if (--num_cpus_frozen)
+			return;
+		/*
+		 * This is the last CPU online operation. So fall through and
+		 * restore the original sched domains by considering the
+		 * cpuset configurations.
+		 */
+		cpuset_force_rebuild();
+	}
+
+	cpuset_update_active_cpus();
+}
+
+static int cpuset_cpu_inactive(unsigned int cpu)
+{
+	if (!cpuhp_tasks_frozen) {
+		cpuset_update_active_cpus();
+	} else {
+		num_cpus_frozen++;
+		partition_sched_domains(1, NULL, NULL);
+	}
+	return 0;
+}
+
+int sched_cpu_activate(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+#ifdef CONFIG_SCHED_SMT
+	/*
+	 * When going up, increment the number of cores with SMT present.
+	 */
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2)
+		static_branch_inc_cpuslocked(&sched_smt_present);
+#endif
+	set_cpu_active(cpu, true);
+
+	if (sched_smp_initialized)
+		cpuset_cpu_active();
+
+	/*
+	 * Put the rq online, if not already. This happens:
+	 *
+	 * 1) In the early boot process, because we build the real domains
+	 *    after all cpus have been brought up.
+	 *
+	 * 2) At runtime, if cpuset_cpu_active() fails to rebuild the
+	 *    domains.
+	 */
+	raw_spin_lock_irqsave(&rq->lock, flags);
+	set_rq_online(rq);
+	raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+	return 0;
+}
+
+int sched_cpu_deactivate(unsigned int cpu)
+{
+	int ret;
+
+	set_cpu_active(cpu, false);
+	/*
+	 * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU
+	 * users of this state to go away such that all new such users will
+	 * observe it.
+	 *
+	 * Do sync before park smpboot threads to take care the rcu boost case.
+	 */
+	synchronize_rcu();
+
+#ifdef CONFIG_SCHED_SMT
+	/*
+	 * When going down, decrement the number of cores with SMT present.
+	 */
+	if (cpumask_weight(cpu_smt_mask(cpu)) == 2) {
+		static_branch_dec_cpuslocked(&sched_smt_present);
+		if (!static_branch_likely(&sched_smt_present))
+			cpumask_clear(&sched_sg_idle_mask);
+	}
+#endif
+
+	if (!sched_smp_initialized)
+		return 0;
+
+	ret = cpuset_cpu_inactive(cpu);
+	if (ret) {
+		set_cpu_active(cpu, true);
+		return ret;
+	}
+	return 0;
+}
+
+static void sched_rq_cpu_starting(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+
+	rq->calc_load_update = calc_load_update;
+}
+
+int sched_cpu_starting(unsigned int cpu)
+{
+	sched_rq_cpu_starting(cpu);
+	sched_tick_start(cpu);
+	return 0;
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+int sched_cpu_dying(unsigned int cpu)
+{
+	struct rq *rq = cpu_rq(cpu);
+	unsigned long flags;
+
+	/* Handle pending wakeups and then migrate everything off */
+	sched_tick_stop(cpu);
+
+	raw_spin_lock_irqsave(&rq->lock, flags);
+	set_rq_offline(rq);
+	migrate_tasks(rq);
+	raw_spin_unlock_irqrestore(&rq->lock, flags);
+
+	hrtick_clear(rq);
+	return 0;
+}
+#endif
+
+#ifdef CONFIG_SMP
+static void sched_init_topology_cpumask_early(void)
+{
+	int cpu, level;
+	cpumask_t *tmp;
+
+	for_each_possible_cpu(cpu) {
+		for (level = 0; level < NR_CPU_AFFINITY_CHK_LEVEL; level++) {
+			tmp = &(per_cpu(sched_cpu_affinity_masks, cpu)[level]);
+			cpumask_copy(tmp, cpu_possible_mask);
+			cpumask_clear_cpu(cpu, tmp);
+		}
+		per_cpu(sched_cpu_llc_mask, cpu) =
+			&(per_cpu(sched_cpu_affinity_masks, cpu)[0]);
+		per_cpu(sched_cpu_affinity_end_mask, cpu) =
+			&(per_cpu(sched_cpu_affinity_masks, cpu)[1]);
+		/*per_cpu(sd_llc_id, cpu) = cpu;*/
+	}
+}
+
+#define TOPOLOGY_CPUMASK(name, mask, last) \
+	if (cpumask_and(chk, chk, mask))					\
+		printk(KERN_INFO "sched: cpu#%02d affinity mask: 0x%08lx - "#name,\
+		       cpu, (chk++)->bits[0]);					\
+	if (!last)								\
+		cpumask_complement(chk, mask)
+
+static void sched_init_topology_cpumask(void)
+{
+	int cpu;
+	cpumask_t *chk;
+
+	for_each_online_cpu(cpu) {
+		/* take chance to reset time slice for idle tasks */
+		cpu_rq(cpu)->idle->time_slice = sched_timeslice_ns;
+
+		chk = &(per_cpu(sched_cpu_affinity_masks, cpu)[0]);
+
+		cpumask_complement(chk, cpumask_of(cpu));
+#ifdef CONFIG_SCHED_SMT
+		TOPOLOGY_CPUMASK(smt, topology_sibling_cpumask(cpu), false);
+#endif
+		per_cpu(sd_llc_id, cpu) = cpumask_first(cpu_coregroup_mask(cpu));
+		per_cpu(sched_cpu_llc_mask, cpu) = chk;
+		TOPOLOGY_CPUMASK(coregroup, cpu_coregroup_mask(cpu), false);
+
+		TOPOLOGY_CPUMASK(core, topology_core_cpumask(cpu), false);
+
+		TOPOLOGY_CPUMASK(others, cpu_online_mask, true);
+
+		per_cpu(sched_cpu_affinity_end_mask, cpu) = chk;
+		printk(KERN_INFO "sched: cpu#%02d llc_id = %d, llc_mask idx = %d\n",
+		       cpu, per_cpu(sd_llc_id, cpu),
+		       (int) (per_cpu(sched_cpu_llc_mask, cpu) -
+			      &(per_cpu(sched_cpu_affinity_masks, cpu)[0])));
+	}
+}
+#endif
+
+void __init sched_init_smp(void)
+{
+	/* Move init over to a non-isolated CPU */
+	if (set_cpus_allowed_ptr(current, housekeeping_cpumask(HK_FLAG_DOMAIN)) < 0)
+		BUG();
+
+	sched_init_topology_cpumask();
+
+	sched_smp_initialized = true;
+}
+#else
+void __init sched_init_smp(void)
+{
+	cpu_rq(0)->idle->time_slice = sched_timeslice_ns;
+}
+#endif /* CONFIG_SMP */
+
+int in_sched_functions(unsigned long addr)
+{
+	return in_lock_functions(addr) ||
+		(addr >= (unsigned long)__sched_text_start
+		&& addr < (unsigned long)__sched_text_end);
+}
+
+#ifdef CONFIG_CGROUP_SCHED
+/* task group related information */
+struct task_group {
+	struct cgroup_subsys_state css;
+
+	struct rcu_head rcu;
+	struct list_head list;
+
+	struct task_group *parent;
+	struct list_head siblings;
+	struct list_head children;
+};
+
+/*
+ * Default task group.
+ * Every task in system belongs to this group at bootup.
+ */
+struct task_group root_task_group;
+LIST_HEAD(task_groups);
+
+/* Cacheline aligned slab cache for task_group */
+static struct kmem_cache *task_group_cache __read_mostly;
+#endif /* CONFIG_CGROUP_SCHED */
+
+void __init sched_init(void)
+{
+	int i;
+	struct rq *rq;
+
+	printk(KERN_INFO ALT_SCHED_VERSION_MSG);
+
+	wait_bit_init();
+
+#ifdef CONFIG_SMP
+	for (i = 0; i < SCHED_BITS; i++)
+		cpumask_copy(&sched_rq_watermark[i], cpu_present_mask);
+#endif
+
+#ifdef CONFIG_CGROUP_SCHED
+	task_group_cache = KMEM_CACHE(task_group, 0);
+
+	list_add(&root_task_group.list, &task_groups);
+	INIT_LIST_HEAD(&root_task_group.children);
+	INIT_LIST_HEAD(&root_task_group.siblings);
+#endif /* CONFIG_CGROUP_SCHED */
+	for_each_possible_cpu(i) {
+		rq = cpu_rq(i);
+
+		sched_queue_init(rq);
+		rq->watermark = IDLE_WM;
+		rq->skip = NULL;
+
+		raw_spin_lock_init(&rq->lock);
+		rq->nr_running = rq->nr_uninterruptible = 0;
+		rq->calc_load_active = 0;
+		rq->calc_load_update = jiffies + LOAD_FREQ;
+#ifdef CONFIG_SMP
+		rq->online = false;
+		rq->cpu = i;
+
+#ifdef CONFIG_SCHED_SMT
+		rq->active_balance = 0;
+#endif
+
+#ifdef CONFIG_NO_HZ_COMMON
+		rq_csd_init(rq, &rq->nohz_csd, nohz_csd_func);
+#endif
+#endif /* CONFIG_SMP */
+		rq->nr_switches = 0;
+
+		hrtick_rq_init(rq);
+		atomic_set(&rq->nr_iowait, 0);
+	}
+#ifdef CONFIG_SMP
+	/* Set rq->online for cpu 0 */
+	cpu_rq(0)->online = true;
+#endif
+	/*
+	 * The boot idle thread does lazy MMU switching as well:
+	 */
+	mmgrab(&init_mm);
+	enter_lazy_tlb(&init_mm, current);
+
+	/*
+	 * Make us the idle thread. Technically, schedule() should not be
+	 * called from this thread, however somewhere below it might be,
+	 * but because we are the idle thread, we just pick up running again
+	 * when this runqueue becomes "idle".
+	 */
+	init_idle(current, smp_processor_id());
+
+	calc_load_update = jiffies + LOAD_FREQ;
+
+#ifdef CONFIG_SMP
+	idle_thread_set_boot_cpu();
+
+	sched_init_topology_cpumask_early();
+#endif /* SMP */
+
+	init_schedstats();
+
+	psi_init();
+}
+
+#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
+static inline int preempt_count_equals(int preempt_offset)
+{
+	int nested = preempt_count() + rcu_preempt_depth();
+
+	return (nested == preempt_offset);
+}
+
+void __might_sleep(const char *file, int line, int preempt_offset)
+{
+	/*
+	 * Blocking primitives will set (and therefore destroy) current->state,
+	 * since we will exit with TASK_RUNNING make sure we enter with it,
+	 * otherwise we will destroy state.
+	 */
+	WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change,
+			"do not call blocking ops when !TASK_RUNNING; "
+			"state=%lx set at [<%p>] %pS\n",
+			current->state,
+			(void *)current->task_state_change,
+			(void *)current->task_state_change);
+
+	___might_sleep(file, line, preempt_offset);
+}
+EXPORT_SYMBOL(__might_sleep);
+
+void ___might_sleep(const char *file, int line, int preempt_offset)
+{
+	/* Ratelimiting timestamp: */
+	static unsigned long prev_jiffy;
+
+	unsigned long preempt_disable_ip;
+
+	/* WARN_ON_ONCE() by default, no rate limit required: */
+	rcu_sleep_check();
+
+	if ((preempt_count_equals(preempt_offset) && !irqs_disabled() &&
+	     !is_idle_task(current) && !current->non_block_count) ||
+	    system_state == SYSTEM_BOOTING || system_state > SYSTEM_RUNNING ||
+	    oops_in_progress)
+		return;
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	/* Save this before calling printk(), since that will clobber it: */
+	preempt_disable_ip = get_preempt_disable_ip(current);
+
+	printk(KERN_ERR
+		"BUG: sleeping function called from invalid context at %s:%d\n",
+			file, line);
+	printk(KERN_ERR
+		"in_atomic(): %d, irqs_disabled(): %d, non_block: %d, pid: %d, name: %s\n",
+			in_atomic(), irqs_disabled(), current->non_block_count,
+			current->pid, current->comm);
+
+	if (task_stack_end_corrupted(current))
+		printk(KERN_EMERG "Thread overran stack, or stack corrupted\n");
+
+	debug_show_held_locks(current);
+	if (irqs_disabled())
+		print_irqtrace_events(current);
+#ifdef CONFIG_DEBUG_PREEMPT
+	if (!preempt_count_equals(preempt_offset)) {
+		pr_err("Preemption disabled at:");
+		print_ip_sym(KERN_ERR, preempt_disable_ip);
+	}
+#endif
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL(___might_sleep);
+
+void __cant_sleep(const char *file, int line, int preempt_offset)
+{
+	static unsigned long prev_jiffy;
+
+	if (irqs_disabled())
+		return;
+
+	if (!IS_ENABLED(CONFIG_PREEMPT_COUNT))
+		return;
+
+	if (preempt_count() > preempt_offset)
+		return;
+
+	if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
+		return;
+	prev_jiffy = jiffies;
+
+	printk(KERN_ERR "BUG: assuming atomic context at %s:%d\n", file, line);
+	printk(KERN_ERR "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n",
+			in_atomic(), irqs_disabled(),
+			current->pid, current->comm);
+
+	debug_show_held_locks(current);
+	dump_stack();
+	add_taint(TAINT_WARN, LOCKDEP_STILL_OK);
+}
+EXPORT_SYMBOL_GPL(__cant_sleep);
+#endif
+
+#ifdef CONFIG_MAGIC_SYSRQ
+void normalize_rt_tasks(void)
+{
+	struct task_struct *g, *p;
+	struct sched_attr attr = {
+		.sched_policy = SCHED_NORMAL,
+	};
+
+	read_lock(&tasklist_lock);
+	for_each_process_thread(g, p) {
+		/*
+		 * Only normalize user tasks:
+		 */
+		if (p->flags & PF_KTHREAD)
+			continue;
+
+		if (!rt_task(p)) {
+			/*
+			 * Renice negative nice level userspace
+			 * tasks back to 0:
+			 */
+			if (task_nice(p) < 0)
+				set_user_nice(p, 0);
+			continue;
+		}
+
+		__sched_setscheduler(p, &attr, false, false);
+	}
+	read_unlock(&tasklist_lock);
+}
+#endif /* CONFIG_MAGIC_SYSRQ */
+
+#if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB)
+/*
+ * These functions are only useful for the IA64 MCA handling, or kdb.
+ *
+ * They can only be called when the whole system has been
+ * stopped - every CPU needs to be quiescent, and no scheduling
+ * activity can take place. Using them for anything else would
+ * be a serious bug, and as a result, they aren't even visible
+ * under any other configuration.
+ */
+
+/**
+ * curr_task - return the current task for a given CPU.
+ * @cpu: the processor in question.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ *
+ * Return: The current task for @cpu.
+ */
+struct task_struct *curr_task(int cpu)
+{
+	return cpu_curr(cpu);
+}
+
+#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */
+
+#ifdef CONFIG_IA64
+/**
+ * ia64_set_curr_task - set the current task for a given CPU.
+ * @cpu: the processor in question.
+ * @p: the task pointer to set.
+ *
+ * Description: This function must only be used when non-maskable interrupts
+ * are serviced on a separate stack.  It allows the architecture to switch the
+ * notion of the current task on a CPU in a non-blocking manner.  This function
+ * must be called with all CPU's synchronised, and interrupts disabled, the
+ * and caller must save the original value of the current task (see
+ * curr_task() above) and restore that value before reenabling interrupts and
+ * re-starting the system.
+ *
+ * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
+ */
+void ia64_set_curr_task(int cpu, struct task_struct *p)
+{
+	cpu_curr(cpu) = p;
+}
+
+#endif
+
+#ifdef CONFIG_CGROUP_SCHED
+static void sched_free_group(struct task_group *tg)
+{
+	kmem_cache_free(task_group_cache, tg);
+}
+
+/* allocate runqueue etc for a new task group */
+struct task_group *sched_create_group(struct task_group *parent)
+{
+	struct task_group *tg;
+
+	tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO);
+	if (!tg)
+		return ERR_PTR(-ENOMEM);
+
+	return tg;
+}
+
+void sched_online_group(struct task_group *tg, struct task_group *parent)
+{
+}
+
+/* rcu callback to free various structures associated with a task group */
+static void sched_free_group_rcu(struct rcu_head *rhp)
+{
+	/* Now it should be safe to free those cfs_rqs */
+	sched_free_group(container_of(rhp, struct task_group, rcu));
+}
+
+void sched_destroy_group(struct task_group *tg)
+{
+	/* Wait for possible concurrent references to cfs_rqs complete */
+	call_rcu(&tg->rcu, sched_free_group_rcu);
+}
+
+void sched_offline_group(struct task_group *tg)
+{
+}
+
+static inline struct task_group *css_tg(struct cgroup_subsys_state *css)
+{
+	return css ? container_of(css, struct task_group, css) : NULL;
+}
+
+static struct cgroup_subsys_state *
+cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
+{
+	struct task_group *parent = css_tg(parent_css);
+	struct task_group *tg;
+
+	if (!parent) {
+		/* This is early initialization for the top cgroup */
+		return &root_task_group.css;
+	}
+
+	tg = sched_create_group(parent);
+	if (IS_ERR(tg))
+		return ERR_PTR(-ENOMEM);
+	return &tg->css;
+}
+
+/* Expose task group only after completing cgroup initialization */
+static int cpu_cgroup_css_online(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+	struct task_group *parent = css_tg(css->parent);
+
+	if (parent)
+		sched_online_group(tg, parent);
+	return 0;
+}
+
+static void cpu_cgroup_css_released(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+
+	sched_offline_group(tg);
+}
+
+static void cpu_cgroup_css_free(struct cgroup_subsys_state *css)
+{
+	struct task_group *tg = css_tg(css);
+
+	/*
+	 * Relies on the RCU grace period between css_released() and this.
+	 */
+	sched_free_group(tg);
+}
+
+static void cpu_cgroup_fork(struct task_struct *task)
+{
+}
+
+static int cpu_cgroup_can_attach(struct cgroup_taskset *tset)
+{
+	return 0;
+}
+
+static void cpu_cgroup_attach(struct cgroup_taskset *tset)
+{
+}
+
+static struct cftype cpu_legacy_files[] = {
+	{ }	/* Terminate */
+};
+
+
+static struct cftype cpu_files[] = {
+	{ }	/* terminate */
+};
+
+static int cpu_extra_stat_show(struct seq_file *sf,
+			       struct cgroup_subsys_state *css)
+{
+	return 0;
+}
+
+struct cgroup_subsys cpu_cgrp_subsys = {
+	.css_alloc	= cpu_cgroup_css_alloc,
+	.css_online	= cpu_cgroup_css_online,
+	.css_released	= cpu_cgroup_css_released,
+	.css_free	= cpu_cgroup_css_free,
+	.css_extra_stat_show = cpu_extra_stat_show,
+	.fork		= cpu_cgroup_fork,
+	.can_attach	= cpu_cgroup_can_attach,
+	.attach		= cpu_cgroup_attach,
+	.legacy_cftypes	= cpu_files,
+	.legacy_cftypes	= cpu_legacy_files,
+	.dfl_cftypes	= cpu_files,
+	.early_init	= true,
+	.threaded	= true,
+};
+#endif	/* CONFIG_CGROUP_SCHED */
+
+#undef CREATE_TRACE_POINTS
diff --git a/kernel/sched/alt_debug.c b/kernel/sched/alt_debug.c
new file mode 100644
index 000000000000..1212a031700e
--- /dev/null
+++ b/kernel/sched/alt_debug.c
@@ -0,0 +1,31 @@
+/*
+ * kernel/sched/alt_debug.c
+ *
+ * Print the alt scheduler debugging details
+ *
+ * Author: Alfred Chen
+ * Date  : 2020
+ */
+#include "sched.h"
+
+/*
+ * This allows printing both to /proc/sched_debug and
+ * to the console
+ */
+#define SEQ_printf(m, x...)			\
+ do {						\
+	if (m)					\
+		seq_printf(m, x);		\
+	else					\
+		pr_cont(x);			\
+ } while (0)
+
+void proc_sched_show_task(struct task_struct *p, struct pid_namespace *ns,
+			  struct seq_file *m)
+{
+	SEQ_printf(m, "%s (%d, #threads: %d)\n", p->comm, task_pid_nr_ns(p, ns),
+						get_nr_threads(p));
+}
+
+void proc_sched_set_task(struct task_struct *p)
+{}
diff --git a/kernel/sched/alt_sched.h b/kernel/sched/alt_sched.h
new file mode 100644
index 000000000000..99be2c51c88d
--- /dev/null
+++ b/kernel/sched/alt_sched.h
@@ -0,0 +1,555 @@
+#ifndef ALT_SCHED_H
+#define ALT_SCHED_H
+
+#include <linux/sched.h>
+
+#include <linux/sched/clock.h>
+#include <linux/sched/cpufreq.h>
+#include <linux/sched/cputime.h>
+#include <linux/sched/debug.h>
+#include <linux/sched/init.h>
+#include <linux/sched/isolation.h>
+#include <linux/sched/loadavg.h>
+#include <linux/sched/mm.h>
+#include <linux/sched/nohz.h>
+#include <linux/sched/signal.h>
+#include <linux/sched/stat.h>
+#include <linux/sched/sysctl.h>
+#include <linux/sched/task.h>
+#include <linux/sched/topology.h>
+#include <linux/sched/wake_q.h>
+
+#include <uapi/linux/sched/types.h>
+
+#include <linux/cgroup.h>
+#include <linux/cpufreq.h>
+#include <linux/cpuidle.h>
+#include <linux/cpuset.h>
+#include <linux/ctype.h>
+#include <linux/kthread.h>
+#include <linux/livepatch.h>
+#include <linux/membarrier.h>
+#include <linux/proc_fs.h>
+#include <linux/psi.h>
+#include <linux/slab.h>
+#include <linux/stop_machine.h>
+#include <linux/suspend.h>
+#include <linux/swait.h>
+#include <linux/syscalls.h>
+#include <linux/tsacct_kern.h>
+
+#include <asm/tlb.h>
+
+#ifdef CONFIG_PARAVIRT
+# include <asm/paravirt.h>
+#endif
+
+#include "cpupri.h"
+
+#ifdef CONFIG_SCHED_BMQ
+#include "bmq.h"
+#endif
+#ifdef CONFIG_SCHED_PDS
+#include "pds.h"
+#endif
+
+/* task_struct::on_rq states: */
+#define TASK_ON_RQ_QUEUED	1
+#define TASK_ON_RQ_MIGRATING	2
+
+static inline int task_on_rq_queued(struct task_struct *p)
+{
+	return p->on_rq == TASK_ON_RQ_QUEUED;
+}
+
+static inline int task_on_rq_migrating(struct task_struct *p)
+{
+	return READ_ONCE(p->on_rq) == TASK_ON_RQ_MIGRATING;
+}
+
+/*
+ * wake flags
+ */
+#define WF_SYNC		0x01		/* waker goes to sleep after wakeup */
+#define WF_FORK		0x02		/* child wakeup after fork */
+#define WF_MIGRATED	0x04		/* internal use, task got migrated */
+#define WF_ON_CPU	0x08		/* Wakee is on_rq */
+
+/*
+ * This is the main, per-CPU runqueue data structure.
+ * This data should only be modified by the local cpu.
+ */
+struct rq {
+	/* runqueue lock: */
+	raw_spinlock_t lock;
+
+	struct task_struct __rcu *curr;
+	struct task_struct *idle, *stop, *skip;
+	struct mm_struct *prev_mm;
+
+#ifdef CONFIG_SCHED_BMQ
+	struct bmq queue;
+#endif
+#ifdef CONFIG_SCHED_PDS
+	struct skiplist_node sl_header;
+#endif
+	unsigned long watermark;
+
+	/* switch count */
+	u64 nr_switches;
+
+	atomic_t nr_iowait;
+
+#ifdef CONFIG_MEMBARRIER
+	int membarrier_state;
+#endif
+
+#ifdef CONFIG_SMP
+	int cpu;		/* cpu of this runqueue */
+	bool online;
+
+	unsigned int		ttwu_pending;
+	unsigned char		nohz_idle_balance;
+	unsigned char		idle_balance;
+
+#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
+	struct sched_avg	avg_irq;
+#endif
+
+#ifdef CONFIG_SCHED_SMT
+	int active_balance;
+	struct cpu_stop_work active_balance_work;
+#endif
+#endif /* CONFIG_SMP */
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+	u64 prev_irq_time;
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+#ifdef CONFIG_PARAVIRT
+	u64 prev_steal_time;
+#endif /* CONFIG_PARAVIRT */
+#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
+	u64 prev_steal_time_rq;
+#endif /* CONFIG_PARAVIRT_TIME_ACCOUNTING */
+
+	/* calc_load related fields */
+	unsigned long calc_load_update;
+	long calc_load_active;
+
+	u64 clock, last_tick;
+	u64 last_ts_switch;
+	u64 clock_task;
+
+	unsigned long nr_running;
+	unsigned long nr_uninterruptible;
+
+#ifdef CONFIG_SCHED_HRTICK
+#ifdef CONFIG_SMP
+	call_single_data_t hrtick_csd;
+#endif
+	struct hrtimer hrtick_timer;
+#endif
+
+#ifdef CONFIG_SCHEDSTATS
+
+	/* latency stats */
+	struct sched_info rq_sched_info;
+	unsigned long long rq_cpu_time;
+	/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
+
+	/* sys_sched_yield() stats */
+	unsigned int yld_count;
+
+	/* schedule() stats */
+	unsigned int sched_switch;
+	unsigned int sched_count;
+	unsigned int sched_goidle;
+
+	/* try_to_wake_up() stats */
+	unsigned int ttwu_count;
+	unsigned int ttwu_local;
+#endif /* CONFIG_SCHEDSTATS */
+
+#ifdef CONFIG_CPU_IDLE
+	/* Must be inspected within a rcu lock section */
+	struct cpuidle_state *idle_state;
+#endif
+
+#ifdef CONFIG_NO_HZ_COMMON
+#ifdef CONFIG_SMP
+	call_single_data_t	nohz_csd;
+#endif
+	atomic_t		nohz_flags;
+#endif /* CONFIG_NO_HZ_COMMON */
+};
+
+extern unsigned long calc_load_update;
+extern atomic_long_t calc_load_tasks;
+
+extern void calc_global_load_tick(struct rq *this_rq);
+extern long calc_load_fold_active(struct rq *this_rq, long adjust);
+
+DECLARE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+#define cpu_rq(cpu)		(&per_cpu(runqueues, (cpu)))
+#define this_rq()		this_cpu_ptr(&runqueues)
+#define task_rq(p)		cpu_rq(task_cpu(p))
+#define cpu_curr(cpu)		(cpu_rq(cpu)->curr)
+#define raw_rq()		raw_cpu_ptr(&runqueues)
+
+#ifdef CONFIG_SMP
+#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
+void register_sched_domain_sysctl(void);
+void unregister_sched_domain_sysctl(void);
+#else
+static inline void register_sched_domain_sysctl(void)
+{
+}
+static inline void unregister_sched_domain_sysctl(void)
+{
+}
+#endif
+
+extern bool sched_smp_initialized;
+
+enum {
+	BASE_CPU_AFFINITY_CHK_LEVEL = 1,
+#ifdef CONFIG_SCHED_SMT
+	SMT_CPU_AFFINITY_CHK_LEVEL_SPACE_HOLDER,
+#endif
+#ifdef CONFIG_SCHED_MC
+	MC_CPU_AFFINITY_CHK_LEVEL_SPACE_HOLDER,
+#endif
+	NR_CPU_AFFINITY_CHK_LEVEL
+};
+
+DECLARE_PER_CPU(cpumask_t [NR_CPU_AFFINITY_CHK_LEVEL], sched_cpu_affinity_masks);
+
+static inline int __best_mask_cpu(int cpu, const cpumask_t *cpumask,
+				  const cpumask_t *mask)
+{
+	while ((cpu = cpumask_any_and(cpumask, mask)) >= nr_cpu_ids)
+		mask++;
+	return cpu;
+}
+
+static inline int best_mask_cpu(int cpu, const cpumask_t *cpumask)
+{
+	return cpumask_test_cpu(cpu, cpumask)? cpu :
+		__best_mask_cpu(cpu, cpumask, &(per_cpu(sched_cpu_affinity_masks, cpu)[0]));
+}
+
+extern void flush_smp_call_function_from_idle(void);
+
+#else  /* !CONFIG_SMP */
+static inline void flush_smp_call_function_from_idle(void) { }
+#endif
+
+#ifndef arch_scale_freq_tick
+static __always_inline
+void arch_scale_freq_tick(void)
+{
+}
+#endif
+
+#ifndef arch_scale_freq_capacity
+static __always_inline
+unsigned long arch_scale_freq_capacity(int cpu)
+{
+	return SCHED_CAPACITY_SCALE;
+}
+#endif
+
+static inline u64 __rq_clock_broken(struct rq *rq)
+{
+	return READ_ONCE(rq->clock);
+}
+
+static inline u64 rq_clock(struct rq *rq)
+{
+	/*
+	 * Relax lockdep_assert_held() checking as in VRQ, call to
+	 * sched_info_xxxx() may not held rq->lock
+	 * lockdep_assert_held(&rq->lock);
+	 */
+	return rq->clock;
+}
+
+static inline u64 rq_clock_task(struct rq *rq)
+{
+	/*
+	 * Relax lockdep_assert_held() checking as in VRQ, call to
+	 * sched_info_xxxx() may not held rq->lock
+	 * lockdep_assert_held(&rq->lock);
+	 */
+	return rq->clock_task;
+}
+
+/*
+ * {de,en}queue flags:
+ *
+ * DEQUEUE_SLEEP  - task is no longer runnable
+ * ENQUEUE_WAKEUP - task just became runnable
+ *
+ */
+
+#define DEQUEUE_SLEEP		0x01
+
+#define ENQUEUE_WAKEUP		0x01
+
+
+/*
+ * Below are scheduler API which using in other kernel code
+ * It use the dummy rq_flags
+ * ToDo : BMQ need to support these APIs for compatibility with mainline
+ * scheduler code.
+ */
+struct rq_flags {
+	unsigned long flags;
+};
+
+struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(rq->lock);
+
+struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf)
+	__acquires(p->pi_lock)
+	__acquires(rq->lock);
+
+static inline void __task_rq_unlock(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	raw_spin_unlock(&rq->lock);
+}
+
+static inline void
+task_rq_unlock(struct rq *rq, struct task_struct *p, struct rq_flags *rf)
+	__releases(rq->lock)
+	__releases(p->pi_lock)
+{
+	raw_spin_unlock(&rq->lock);
+	raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags);
+}
+
+static inline void
+rq_unlock_irq(struct rq *rq, struct rq_flags *rf)
+	__releases(rq->lock)
+{
+	raw_spin_unlock_irq(&rq->lock);
+}
+
+static inline struct rq *
+this_rq_lock_irq(struct rq_flags *rf)
+	__acquires(rq->lock)
+{
+	struct rq *rq;
+
+	local_irq_disable();
+	rq = this_rq();
+	raw_spin_lock(&rq->lock);
+
+	return rq;
+}
+
+static inline int task_current(struct rq *rq, struct task_struct *p)
+{
+	return rq->curr == p;
+}
+
+static inline bool task_running(struct task_struct *p)
+{
+	return p->on_cpu;
+}
+
+extern struct static_key_false sched_schedstats;
+
+#ifdef CONFIG_CPU_IDLE
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+	rq->idle_state = idle_state;
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	WARN_ON(!rcu_read_lock_held());
+	return rq->idle_state;
+}
+#else
+static inline void idle_set_state(struct rq *rq,
+				  struct cpuidle_state *idle_state)
+{
+}
+
+static inline struct cpuidle_state *idle_get_state(struct rq *rq)
+{
+	return NULL;
+}
+#endif
+
+static inline int cpu_of(const struct rq *rq)
+{
+#ifdef CONFIG_SMP
+	return rq->cpu;
+#else
+	return 0;
+#endif
+}
+
+#include "stats.h"
+
+#ifdef CONFIG_NO_HZ_COMMON
+#define NOHZ_BALANCE_KICK_BIT	0
+#define NOHZ_STATS_KICK_BIT	1
+
+#define NOHZ_BALANCE_KICK	BIT(NOHZ_BALANCE_KICK_BIT)
+#define NOHZ_STATS_KICK		BIT(NOHZ_STATS_KICK_BIT)
+
+#define NOHZ_KICK_MASK	(NOHZ_BALANCE_KICK | NOHZ_STATS_KICK)
+
+#define nohz_flags(cpu)	(&cpu_rq(cpu)->nohz_flags)
+
+/* TODO: needed?
+extern void nohz_balance_exit_idle(struct rq *rq);
+#else
+static inline void nohz_balance_exit_idle(struct rq *rq) { }
+*/
+#endif
+
+#ifdef CONFIG_IRQ_TIME_ACCOUNTING
+struct irqtime {
+	u64			total;
+	u64			tick_delta;
+	u64			irq_start_time;
+	struct u64_stats_sync	sync;
+};
+
+DECLARE_PER_CPU(struct irqtime, cpu_irqtime);
+
+/*
+ * Returns the irqtime minus the softirq time computed by ksoftirqd.
+ * Otherwise ksoftirqd's sum_exec_runtime is substracted its own runtime
+ * and never move forward.
+ */
+static inline u64 irq_time_read(int cpu)
+{
+	struct irqtime *irqtime = &per_cpu(cpu_irqtime, cpu);
+	unsigned int seq;
+	u64 total;
+
+	do {
+		seq = __u64_stats_fetch_begin(&irqtime->sync);
+		total = irqtime->total;
+	} while (__u64_stats_fetch_retry(&irqtime->sync, seq));
+
+	return total;
+}
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#ifdef CONFIG_CPU_FREQ
+DECLARE_PER_CPU(struct update_util_data __rcu *, cpufreq_update_util_data);
+
+/**
+ * cpufreq_update_util - Take a note about CPU utilization changes.
+ * @rq: Runqueue to carry out the update for.
+ * @flags: Update reason flags.
+ *
+ * This function is called by the scheduler on the CPU whose utilization is
+ * being updated.
+ *
+ * It can only be called from RCU-sched read-side critical sections.
+ *
+ * The way cpufreq is currently arranged requires it to evaluate the CPU
+ * performance state (frequency/voltage) on a regular basis to prevent it from
+ * being stuck in a completely inadequate performance level for too long.
+ * That is not guaranteed to happen if the updates are only triggered from CFS
+ * and DL, though, because they may not be coming in if only RT tasks are
+ * active all the time (or there are RT tasks only).
+ *
+ * As a workaround for that issue, this function is called periodically by the
+ * RT sched class to trigger extra cpufreq updates to prevent it from stalling,
+ * but that really is a band-aid.  Going forward it should be replaced with
+ * solutions targeted more specifically at RT tasks.
+ */
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags)
+{
+	struct update_util_data *data;
+
+	data = rcu_dereference_sched(*this_cpu_ptr(&cpufreq_update_util_data));
+	if (data)
+		data->func(data, rq_clock(rq), flags);
+}
+#else
+static inline void cpufreq_update_util(struct rq *rq, unsigned int flags) {}
+#endif /* CONFIG_CPU_FREQ */
+
+#ifdef CONFIG_NO_HZ_FULL
+extern int __init sched_tick_offload_init(void);
+#else
+static inline int sched_tick_offload_init(void) { return 0; }
+#endif
+
+#ifdef arch_scale_freq_capacity
+#ifndef arch_scale_freq_invariant
+#define arch_scale_freq_invariant()	(true)
+#endif
+#else /* arch_scale_freq_capacity */
+#define arch_scale_freq_invariant()	(false)
+#endif
+
+extern void schedule_idle(void);
+
+/*
+ * !! For sched_setattr_nocheck() (kernel) only !!
+ *
+ * This is actually gross. :(
+ *
+ * It is used to make schedutil kworker(s) higher priority than SCHED_DEADLINE
+ * tasks, but still be able to sleep. We need this on platforms that cannot
+ * atomically change clock frequency. Remove once fast switching will be
+ * available on such platforms.
+ *
+ * SUGOV stands for SchedUtil GOVernor.
+ */
+#define SCHED_FLAG_SUGOV	0x10000000
+
+#ifdef CONFIG_MEMBARRIER
+/*
+ * The scheduler provides memory barriers required by membarrier between:
+ * - prior user-space memory accesses and store to rq->membarrier_state,
+ * - store to rq->membarrier_state and following user-space memory accesses.
+ * In the same way it provides those guarantees around store to rq->curr.
+ */
+static inline void membarrier_switch_mm(struct rq *rq,
+					struct mm_struct *prev_mm,
+					struct mm_struct *next_mm)
+{
+	int membarrier_state;
+
+	if (prev_mm == next_mm)
+		return;
+
+	membarrier_state = atomic_read(&next_mm->membarrier_state);
+	if (READ_ONCE(rq->membarrier_state) == membarrier_state)
+		return;
+
+	WRITE_ONCE(rq->membarrier_state, membarrier_state);
+}
+#else
+static inline void membarrier_switch_mm(struct rq *rq,
+					struct mm_struct *prev_mm,
+					struct mm_struct *next_mm)
+{
+}
+#endif
+
+#ifdef CONFIG_NUMA
+extern int sched_numa_find_closest(const struct cpumask *cpus, int cpu);
+#else
+static inline int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
+{
+	return nr_cpu_ids;
+}
+#endif
+
+void swake_up_all_locked(struct swait_queue_head *q);
+void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
+
+#endif /* ALT_SCHED_H */
diff --git a/kernel/sched/bmq.h b/kernel/sched/bmq.h
new file mode 100644
index 000000000000..aff0bb30a884
--- /dev/null
+++ b/kernel/sched/bmq.h
@@ -0,0 +1,20 @@
+#ifndef BMQ_H
+#define BMQ_H
+
+/* bits:
+ * RT(0-99), (Low prio adj range, nice width, high prio adj range) / 2, cpu idle task */
+#define SCHED_BITS	(MAX_RT_PRIO + NICE_WIDTH / 2 + MAX_PRIORITY_ADJ + 1)
+#define IDLE_TASK_SCHED_PRIO	(SCHED_BITS - 1)
+
+struct bmq {
+	DECLARE_BITMAP(bitmap, SCHED_BITS);
+	struct list_head heads[SCHED_BITS];
+};
+
+
+static inline int task_running_nice(struct task_struct *p)
+{
+	return (p->prio + p->boost_prio > DEFAULT_PRIO + MAX_PRIORITY_ADJ);
+}
+
+#endif
diff --git a/kernel/sched/bmq_imp.h b/kernel/sched/bmq_imp.h
new file mode 100644
index 000000000000..ad9a7c448da7
--- /dev/null
+++ b/kernel/sched/bmq_imp.h
@@ -0,0 +1,185 @@
+#define ALT_SCHED_VERSION_MSG "sched/bmq: BMQ CPU Scheduler "ALT_SCHED_VERSION" by Alfred Chen.\n"
+
+/*
+ * BMQ only routines
+ */
+#define rq_switch_time(rq)	((rq)->clock - (rq)->last_ts_switch)
+#define boost_threshold(p)	(sched_timeslice_ns >>\
+				 (15 - MAX_PRIORITY_ADJ -  (p)->boost_prio))
+
+static inline void boost_task(struct task_struct *p)
+{
+	int limit;
+
+	switch (p->policy) {
+	case SCHED_NORMAL:
+		limit = -MAX_PRIORITY_ADJ;
+		break;
+	case SCHED_BATCH:
+	case SCHED_IDLE:
+		limit = 0;
+		break;
+	default:
+		return;
+	}
+
+	if (p->boost_prio > limit)
+		p->boost_prio--;
+}
+
+static inline void deboost_task(struct task_struct *p)
+{
+	if (p->boost_prio < MAX_PRIORITY_ADJ)
+		p->boost_prio++;
+}
+
+/*
+ * Common interfaces
+ */
+static inline int task_sched_prio(struct task_struct *p, struct rq *rq)
+{
+	return (p->prio < MAX_RT_PRIO)? p->prio : MAX_RT_PRIO / 2 + (p->prio + p->boost_prio) / 2;
+}
+
+static inline void requeue_task(struct task_struct *p, struct rq *rq);
+
+static inline void time_slice_expired(struct task_struct *p, struct rq *rq)
+{
+	p->time_slice = sched_timeslice_ns;
+
+	if (SCHED_FIFO != p->policy && task_on_rq_queued(p)) {
+		if (SCHED_RR != p->policy)
+			deboost_task(p);
+		requeue_task(p, rq);
+	}
+}
+
+static inline void update_task_priodl(struct task_struct *p) {}
+
+static inline unsigned long sched_queue_watermark(struct rq *rq)
+{
+	return find_first_bit(rq->queue.bitmap, SCHED_BITS);
+}
+
+static inline void sched_queue_init(struct rq *rq)
+{
+	struct bmq *q = &rq->queue;
+	int i;
+
+	bitmap_zero(q->bitmap, SCHED_BITS);
+	for(i = 0; i < SCHED_BITS; i++)
+		INIT_LIST_HEAD(&q->heads[i]);
+}
+
+static inline void sched_queue_init_idle(struct rq *rq, struct task_struct *idle)
+{
+	struct bmq *q = &rq->queue;
+
+	idle->bmq_idx = IDLE_TASK_SCHED_PRIO;
+	INIT_LIST_HEAD(&q->heads[idle->bmq_idx]);
+	list_add(&idle->bmq_node, &q->heads[idle->bmq_idx]);
+	set_bit(idle->bmq_idx, q->bitmap);
+}
+
+/*
+ * This routine used in bmq scheduler only which assume the idle task in the bmq
+ */
+static inline struct task_struct *sched_rq_first_task(struct rq *rq)
+{
+	unsigned long idx = find_first_bit(rq->queue.bitmap, SCHED_BITS);
+	const struct list_head *head = &rq->queue.heads[idx];
+
+	return list_first_entry(head, struct task_struct, bmq_node);
+}
+
+static inline struct task_struct *
+sched_rq_next_task(struct task_struct *p, struct rq *rq)
+{
+	unsigned long idx = p->bmq_idx;
+	struct list_head *head = &rq->queue.heads[idx];
+
+	if (list_is_last(&p->bmq_node, head)) {
+		idx = find_next_bit(rq->queue.bitmap, SCHED_BITS, idx + 1);
+		head = &rq->queue.heads[idx];
+
+		return list_first_entry(head, struct task_struct, bmq_node);
+	}
+
+	return list_next_entry(p, bmq_node);
+}
+
+#define __SCHED_DEQUEUE_TASK(p, rq, flags, func)	\
+	psi_dequeue(p, flags & DEQUEUE_SLEEP);		\
+	sched_info_dequeued(rq, p);			\
+							\
+	list_del(&p->bmq_node);				\
+	if (list_empty(&rq->queue.heads[p->bmq_idx])) {	\
+		clear_bit(p->bmq_idx, rq->queue.bitmap);\
+		func;					\
+	}
+
+#define __SCHED_ENQUEUE_TASK(p, rq, flags)				\
+	sched_info_queued(rq, p);					\
+	psi_enqueue(p, flags);						\
+									\
+	p->bmq_idx = task_sched_prio(p, rq);				\
+	list_add_tail(&p->bmq_node, &rq->queue.heads[p->bmq_idx]);	\
+	set_bit(p->bmq_idx, rq->queue.bitmap)
+
+#define __SCHED_REQUEUE_TASK(p, rq, func)				\
+{									\
+	int idx = task_sched_prio(p, rq);				\
+\
+	list_del(&p->bmq_node);						\
+	list_add_tail(&p->bmq_node, &rq->queue.heads[idx]);		\
+	if (idx != p->bmq_idx) {					\
+		if (list_empty(&rq->queue.heads[p->bmq_idx]))		\
+			clear_bit(p->bmq_idx, rq->queue.bitmap);	\
+		p->bmq_idx = idx;					\
+		set_bit(p->bmq_idx, rq->queue.bitmap);			\
+		func;							\
+	}								\
+}
+
+static inline bool sched_task_need_requeue(struct task_struct *p, struct rq *rq)
+{
+	return (task_sched_prio(p, rq) != p->bmq_idx);
+}
+
+static void sched_task_fork(struct task_struct *p, struct rq *rq)
+{
+	p->boost_prio = (p->boost_prio < 0) ?
+		p->boost_prio + MAX_PRIORITY_ADJ : MAX_PRIORITY_ADJ;
+}
+
+/**
+ * task_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * Return: The priority value as seen by users in /proc.
+ * RT tasks are offset by -100. Normal tasks are centered around 1, value goes
+ * from 0(SCHED_ISO) up to 82 (nice +19 SCHED_IDLE).
+ */
+int task_prio(const struct task_struct *p)
+{
+	if (p->prio < MAX_RT_PRIO)
+		return (p->prio - MAX_RT_PRIO);
+	return (p->prio - MAX_RT_PRIO + p->boost_prio);
+}
+
+static void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
+{
+	p->boost_prio = MAX_PRIORITY_ADJ;
+}
+
+static void sched_task_ttwu(struct task_struct *p)
+{
+	if(this_rq()->clock_task - p->last_ran > sched_timeslice_ns)
+		boost_task(p);
+}
+
+static void sched_task_deactivate(struct task_struct *p, struct rq *rq)
+{
+	if (rq_switch_time(rq) < boost_threshold(p))
+		boost_task(p);
+}
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index e39008242cf4..5963716fe391 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -183,6 +183,7 @@ static unsigned int get_next_freq(struct sugov_policy *sg_policy,
 	return cpufreq_driver_resolve_freq(policy, freq);
 }
 
+#ifndef CONFIG_SCHED_ALT
 /*
  * This function computes an effective utilization for the given CPU, to be
  * used for frequency selection given the linear relation: f = u * f_max.
@@ -300,6 +301,13 @@ static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
 
 	return schedutil_cpu_util(sg_cpu->cpu, util, max, FREQUENCY_UTIL, NULL);
 }
+#else /* CONFIG_SCHED_ALT */
+static unsigned long sugov_get_util(struct sugov_cpu *sg_cpu)
+{
+	sg_cpu->max = arch_scale_cpu_capacity(sg_cpu->cpu);
+	return sg_cpu->max;
+}
+#endif
 
 /**
  * sugov_iowait_reset() - Reset the IO boost status of a CPU.
@@ -443,7 +451,9 @@ static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
  */
 static inline void ignore_dl_rate_limit(struct sugov_cpu *sg_cpu, struct sugov_policy *sg_policy)
 {
+#ifndef CONFIG_SCHED_ALT
 	if (cpu_bw_dl(cpu_rq(sg_cpu->cpu)) > sg_cpu->bw_dl)
+#endif
 		sg_policy->limits_changed = true;
 }
 
@@ -686,6 +696,7 @@ static int sugov_kthread_create(struct sugov_policy *sg_policy)
 	}
 
 	ret = sched_setattr_nocheck(thread, &attr);
+
 	if (ret) {
 		kthread_stop(thread);
 		pr_warn("%s: failed to set SCHED_DEADLINE\n", __func__);
@@ -912,6 +923,7 @@ struct cpufreq_governor *cpufreq_default_governor(void)
 cpufreq_governor_init(schedutil_gov);
 
 #ifdef CONFIG_ENERGY_MODEL
+#ifndef CONFIG_SCHED_ALT
 extern bool sched_energy_update;
 extern struct mutex sched_energy_mutex;
 
@@ -942,4 +954,10 @@ void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
 	}
 
 }
+#else /* CONFIG_SCHED_ALT */
+void sched_cpufreq_governor_change(struct cpufreq_policy *policy,
+				  struct cpufreq_governor *old_gov)
+{
+}
+#endif
 #endif
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 5a55d2300452..66a0ab7165f0 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -122,7 +122,7 @@ void account_user_time(struct task_struct *p, u64 cputime)
 	p->utime += cputime;
 	account_group_user_time(p, cputime);
 
-	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
+	index = task_running_nice(p) ? CPUTIME_NICE : CPUTIME_USER;
 
 	/* Add user time to cpustat. */
 	task_group_account_field(p, index, cputime);
@@ -146,7 +146,7 @@ void account_guest_time(struct task_struct *p, u64 cputime)
 	p->gtime += cputime;
 
 	/* Add guest time to cpustat. */
-	if (task_nice(p) > 0) {
+	if (task_running_nice(p)) {
 		cpustat[CPUTIME_NICE] += cputime;
 		cpustat[CPUTIME_GUEST_NICE] += cputime;
 	} else {
@@ -269,7 +269,7 @@ static inline u64 account_other_time(u64 max)
 #ifdef CONFIG_64BIT
 static inline u64 read_sum_exec_runtime(struct task_struct *t)
 {
-	return t->se.sum_exec_runtime;
+	return tsk_seruntime(t);
 }
 #else
 static u64 read_sum_exec_runtime(struct task_struct *t)
@@ -279,7 +279,7 @@ static u64 read_sum_exec_runtime(struct task_struct *t)
 	struct rq *rq;
 
 	rq = task_rq_lock(t, &rf);
-	ns = t->se.sum_exec_runtime;
+	ns = tsk_seruntime(t);
 	task_rq_unlock(rq, t, &rf);
 
 	return ns;
@@ -614,7 +614,7 @@ void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
 void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
 {
 	struct task_cputime cputime = {
-		.sum_exec_runtime = p->se.sum_exec_runtime,
+		.sum_exec_runtime = tsk_seruntime(p),
 	};
 
 	task_cputime(p, &cputime.utime, &cputime.stime);
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index f324dc36fc43..a6b566bda65b 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -369,6 +369,7 @@ void cpu_startup_entry(enum cpuhp_state state)
 		do_idle();
 }
 
+#ifndef CONFIG_SCHED_ALT
 /*
  * idle-task scheduling class.
  */
@@ -482,3 +483,4 @@ const struct sched_class idle_sched_class
 	.switched_to		= switched_to_idle,
 	.update_curr		= update_curr_idle,
 };
+#endif
diff --git a/kernel/sched/pds.h b/kernel/sched/pds.h
new file mode 100644
index 000000000000..7fdeace7e8a5
--- /dev/null
+++ b/kernel/sched/pds.h
@@ -0,0 +1,14 @@
+#ifndef PDS_H
+#define PDS_H
+
+/* bits:
+ * RT(0-99), (Low prio adj range, nice width, high prio adj range) / 2, cpu idle task */
+#define SCHED_BITS	(MAX_RT_PRIO + 20 + 1)
+#define IDLE_TASK_SCHED_PRIO	(SCHED_BITS - 1)
+
+static inline int task_running_nice(struct task_struct *p)
+{
+	return (p->prio > DEFAULT_PRIO);
+}
+
+#endif
diff --git a/kernel/sched/pds_imp.h b/kernel/sched/pds_imp.h
new file mode 100644
index 000000000000..6baee5e961b9
--- /dev/null
+++ b/kernel/sched/pds_imp.h
@@ -0,0 +1,257 @@
+#define ALT_SCHED_VERSION_MSG "sched/pds: PDS CPU Scheduler "ALT_SCHED_VERSION" by Alfred Chen.\n"
+
+static const u64 user_prio2deadline[NICE_WIDTH] = {
+/* -20 */	  4194304,   4613734,   5075107,   5582617,   6140878,
+/* -15 */	  6754965,   7430461,   8173507,   8990857,   9889942,
+/* -10 */	 10878936,  11966829,  13163511,  14479862,  15927848,
+/*  -5 */	 17520632,  19272695,  21199964,  23319960,  25651956,
+/*   0 */	 28217151,  31038866,  34142752,  37557027,  41312729,
+/*   5 */	 45444001,  49988401,  54987241,  60485965,  66534561,
+/*  10 */	 73188017,  80506818,  88557499,  97413248, 107154572,
+/*  15 */	117870029, 129657031, 142622734, 156885007, 172573507
+};
+
+static const unsigned char dl_level_map[] = {
+/*       0               4               8              12           */
+	19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 19, 18,
+/*      16              20              24              28           */
+	18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 18, 17, 17, 17, 17, 17,
+/*      32              36              40              44           */
+	17, 17, 17, 17, 16, 16, 16, 16, 16, 16, 16, 16, 15, 15, 15, 15,
+/*      48              52              56              60           */
+	15, 15, 15, 14, 14, 14, 14, 14, 14, 13, 13, 13, 13, 12, 12, 12,
+/*      64              68              72              76           */
+	12, 11, 11, 11, 10, 10, 10,  9,  9,  8,  7,  6,  5,  4,  3,  2,
+/*      80              84              88              92           */
+	 1,  0
+};
+
+static inline int
+task_sched_prio(const struct task_struct *p, const struct rq *rq)
+{
+	size_t delta;
+
+	if (p == rq->idle)
+		return IDLE_TASK_SCHED_PRIO;
+
+	if (p->prio < MAX_RT_PRIO)
+		return p->prio;
+
+	delta = (rq->clock + user_prio2deadline[39] - p->deadline) >> 21;
+	delta = min((size_t)delta, ARRAY_SIZE(dl_level_map) - 1);
+
+	return MAX_RT_PRIO + dl_level_map[delta];
+}
+
+static inline void update_task_priodl(struct task_struct *p)
+{
+	p->priodl = (((u64) (p->prio))<<56) | ((p->deadline)>>8);
+}
+
+static inline void requeue_task(struct task_struct *p, struct rq *rq);
+
+static inline void time_slice_expired(struct task_struct *p, struct rq *rq)
+{
+	/*printk(KERN_INFO "sched: time_slice_expired(%d) - %px\n", cpu_of(rq), p);*/
+	p->time_slice = sched_timeslice_ns;
+
+	if (p->prio >= MAX_RT_PRIO)
+		p->deadline = rq->clock + user_prio2deadline[TASK_USER_PRIO(p)];
+	update_task_priodl(p);
+
+	if (SCHED_FIFO != p->policy && task_on_rq_queued(p))
+		requeue_task(p, rq);
+}
+
+/*
+ * pds_skiplist_task_search -- search function used in PDS run queue skip list
+ * node insert operation.
+ * @it: iterator pointer to the node in the skip list
+ * @node: pointer to the skiplist_node to be inserted
+ *
+ * Returns true if key of @it is less or equal to key value of @node, otherwise
+ * false.
+ */
+static inline bool
+pds_skiplist_task_search(struct skiplist_node *it, struct skiplist_node *node)
+{
+	return (skiplist_entry(it, struct task_struct, sl_node)->priodl <=
+		skiplist_entry(node, struct task_struct, sl_node)->priodl);
+}
+
+/*
+ * Define the skip list insert function for PDS
+ */
+DEFINE_SKIPLIST_INSERT_FUNC(pds_skiplist_insert, pds_skiplist_task_search);
+
+/*
+ * Init the queue structure in rq
+ */
+static inline void sched_queue_init(struct rq *rq)
+{
+	FULL_INIT_SKIPLIST_NODE(&rq->sl_header);
+}
+
+/*
+ * Init idle task and put into queue structure of rq
+ * IMPORTANT: may be called multiple times for a single cpu
+ */
+static inline void sched_queue_init_idle(struct rq *rq, struct task_struct *idle)
+{
+	/*printk(KERN_INFO "sched: init(%d) - %px\n", cpu_of(rq), idle);*/
+	int default_prio = idle->prio;
+
+	idle->prio = MAX_PRIO;
+	idle->deadline = 0ULL;
+	update_task_priodl(idle);
+
+	FULL_INIT_SKIPLIST_NODE(&rq->sl_header);
+
+	idle->sl_node.level = idle->sl_level;
+	pds_skiplist_insert(&rq->sl_header, &idle->sl_node);
+
+	idle->prio = default_prio;
+}
+
+/*
+ * This routine assume that the idle task always in queue
+ */
+static inline struct task_struct *sched_rq_first_task(struct rq *rq)
+{
+	struct skiplist_node *node = rq->sl_header.next[0];
+
+	BUG_ON(node == &rq->sl_header);
+	return skiplist_entry(node, struct task_struct, sl_node);
+}
+
+static inline struct task_struct *
+sched_rq_next_task(struct task_struct *p, struct rq *rq)
+{
+	struct skiplist_node *next = p->sl_node.next[0];
+
+	BUG_ON(next == &rq->sl_header);
+	return skiplist_entry(next, struct task_struct, sl_node);
+}
+
+static inline unsigned long sched_queue_watermark(struct rq *rq)
+{
+	return task_sched_prio(sched_rq_first_task(rq), rq);
+}
+
+#define __SCHED_DEQUEUE_TASK(p, rq, flags, func)		\
+	psi_dequeue(p, flags & DEQUEUE_SLEEP);			\
+	sched_info_dequeued(rq, p);				\
+								\
+	if (skiplist_del_init(&rq->sl_header, &p->sl_node)) {	\
+		func;						\
+	}
+
+#define __SCHED_ENQUEUE_TASK(p, rq, flags)				\
+	sched_info_queued(rq, p);					\
+	psi_enqueue(p, flags);						\
+									\
+	p->sl_node.level = p->sl_level;					\
+	pds_skiplist_insert(&rq->sl_header, &p->sl_node)
+
+/*
+ * Requeue a task @p to @rq
+ */
+#define __SCHED_REQUEUE_TASK(p, rq, func)					\
+{\
+	bool b_first = skiplist_del_init(&rq->sl_header, &p->sl_node);		\
+\
+	p->sl_node.level = p->sl_level;						\
+	if (pds_skiplist_insert(&rq->sl_header, &p->sl_node) || b_first) {	\
+		func;								\
+	}									\
+}
+
+static inline bool sched_task_need_requeue(struct task_struct *p, struct rq *rq)
+{
+	struct skiplist_node *node = p->sl_node.prev[0];
+
+	if (node != &rq->sl_header) {
+		struct task_struct *t = skiplist_entry(node, struct task_struct, sl_node);
+
+		if (t->priodl > p->priodl)
+			return true;
+	}
+
+	node = p->sl_node.next[0];
+	if (node != &rq->sl_header) {
+		struct task_struct *t = skiplist_entry(node, struct task_struct, sl_node);
+
+		if (t->priodl < p->priodl)
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * pds_skiplist_random_level -- Returns a pseudo-random level number for skip
+ * list node which is used in PDS run queue.
+ *
+ * In current implementation, based on testing, the first 8 bits in microseconds
+ * of niffies are suitable for random level population.
+ * find_first_bit() is used to satisfy p = 0.5 between each levels, and there
+ * should be platform hardware supported instruction(known as ctz/clz) to speed
+ * up this function.
+ * The skiplist level for a task is populated when task is created and doesn't
+ * change in task's life time. When task is being inserted into run queue, this
+ * skiplist level is set to task's sl_node->level, the skiplist insert function
+ * may change it based on current level of the skip lsit.
+ */
+static inline int pds_skiplist_random_level(const struct task_struct *p)
+{
+	long unsigned int randseed;
+
+	/*
+	 * 1. Some architectures don't have better than microsecond resolution
+	 * so mask out ~microseconds as a factor of the random seed for skiplist
+	 * insertion.
+	 * 2. Use address of task structure pointer as another factor of the
+	 * random seed for task burst forking scenario.
+	 */
+	randseed = (task_rq(p)->clock ^ (long unsigned int)p) >> 10;
+
+	return find_first_bit(&randseed, NUM_SKIPLIST_LEVEL - 1);
+}
+
+static void sched_task_fork(struct task_struct *p, struct rq *rq)
+{
+	p->sl_level = pds_skiplist_random_level(p);
+	if (p->prio >= MAX_RT_PRIO)
+		p->deadline = rq->clock + user_prio2deadline[TASK_USER_PRIO(p)];
+	update_task_priodl(p);
+}
+
+/**
+ * task_prio - return the priority value of a given task.
+ * @p: the task in question.
+ *
+ * Return: The priority value as seen by users in /proc.
+ * RT tasks are offset by -100. Normal tasks are centered around 1, value goes
+ * from 0(SCHED_ISO) up to 82 (nice +19 SCHED_IDLE).
+ */
+int task_prio(const struct task_struct *p)
+{
+	int ret;
+
+	if (p->prio < MAX_RT_PRIO)
+		return (p->prio - MAX_RT_PRIO);
+
+	preempt_disable();
+	ret = task_sched_prio(p, this_rq()) - MAX_RT_PRIO;
+	preempt_enable();
+
+	return ret;
+}
+
+static void do_sched_yield_type_1(struct task_struct *p, struct rq *rq)
+{
+	time_slice_expired(p, rq);
+}
+
+static void sched_task_ttwu(struct task_struct *p) {}
+static void sched_task_deactivate(struct task_struct *p, struct rq *rq) {}
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
index 2c613e1cff3a..0103b2a7201d 100644
--- a/kernel/sched/pelt.c
+++ b/kernel/sched/pelt.c
@@ -270,6 +270,7 @@ ___update_load_avg(struct sched_avg *sa, unsigned long load)
 	WRITE_ONCE(sa->util_avg, sa->util_sum / divider);
 }
 
+#ifndef CONFIG_SCHED_ALT
 /*
  * sched_entity:
  *
@@ -387,8 +388,9 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
 
 	return 0;
 }
+#endif
 
-#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+#if defined(CONFIG_SCHED_THERMAL_PRESSURE) && !defined(CONFIG_SCHED_ALT)
 /*
  * thermal:
  *
diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
index 795e43e02afc..856163dac896 100644
--- a/kernel/sched/pelt.h
+++ b/kernel/sched/pelt.h
@@ -1,13 +1,15 @@
 #ifdef CONFIG_SMP
 #include "sched-pelt.h"
 
+#ifndef CONFIG_SCHED_ALT
 int __update_load_avg_blocked_se(u64 now, struct sched_entity *se);
 int __update_load_avg_se(u64 now, struct cfs_rq *cfs_rq, struct sched_entity *se);
 int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
 int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
 int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
+#endif
 
-#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+#if defined(CONFIG_SCHED_THERMAL_PRESSURE) && !defined(CONFIG_SCHED_ALT)
 int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
 
 static inline u64 thermal_load_avg(struct rq *rq)
@@ -42,6 +44,7 @@ static inline u32 get_pelt_divider(struct sched_avg *avg)
 	return LOAD_AVG_MAX - 1024 + avg->period_contrib;
 }
 
+#ifndef CONFIG_SCHED_ALT
 /*
  * When a task is dequeued, its estimated utilization should not be update if
  * its util_avg has not been updated at least once.
@@ -162,9 +165,11 @@ static inline u64 cfs_rq_clock_pelt(struct cfs_rq *cfs_rq)
 	return rq_clock_pelt(rq_of(cfs_rq));
 }
 #endif
+#endif /* CONFIG_SCHED_ALT */
 
 #else
 
+#ifndef CONFIG_SCHED_ALT
 static inline int
 update_cfs_rq_load_avg(u64 now, struct cfs_rq *cfs_rq)
 {
@@ -182,6 +187,7 @@ update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
 {
 	return 0;
 }
+#endif
 
 static inline int
 update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 28709f6b0975..6bc68bacbac8 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -2,6 +2,10 @@
 /*
  * Scheduler internal types and methods:
  */
+#ifdef CONFIG_SCHED_ALT
+#include "alt_sched.h"
+#else
+
 #include <linux/sched.h>
 
 #include <linux/sched/autogroup.h>
@@ -2626,3 +2630,9 @@ static inline bool is_per_cpu_kthread(struct task_struct *p)
 
 void swake_up_all_locked(struct swait_queue_head *q);
 void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait);
+
+static inline int task_running_nice(struct task_struct *p)
+{
+	return (task_nice(p) > 0);
+}
+#endif /* !CONFIG_SCHED_ALT */
diff --git a/kernel/sched/stats.c b/kernel/sched/stats.c
index 750fb3c67eed..108422ebc7bf 100644
--- a/kernel/sched/stats.c
+++ b/kernel/sched/stats.c
@@ -22,8 +22,10 @@ static int show_schedstat(struct seq_file *seq, void *v)
 	} else {
 		struct rq *rq;
 #ifdef CONFIG_SMP
+#ifndef CONFIG_SCHED_ALT
 		struct sched_domain *sd;
 		int dcount = 0;
+#endif
 #endif
 		cpu = (unsigned long)(v - 2);
 		rq = cpu_rq(cpu);
@@ -40,6 +42,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
 		seq_printf(seq, "\n");
 
 #ifdef CONFIG_SMP
+#ifndef CONFIG_SCHED_ALT
 		/* domain-specific stats */
 		rcu_read_lock();
 		for_each_domain(cpu, sd) {
@@ -68,6 +71,7 @@ static int show_schedstat(struct seq_file *seq, void *v)
 			    sd->ttwu_move_balance);
 		}
 		rcu_read_unlock();
+#endif
 #endif
 	}
 	return 0;
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 1bd7e3af904f..cc946a9bd550 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -4,6 +4,7 @@
  */
 #include "sched.h"
 
+#ifndef CONFIG_SCHED_ALT
 DEFINE_MUTEX(sched_domains_mutex);
 
 /* Protected by sched_domains_mutex: */
@@ -1180,8 +1181,10 @@ static void init_sched_groups_capacity(int cpu, struct sched_domain *sd)
  */
 
 static int default_relax_domain_level = -1;
+#endif /* CONFIG_SCHED_ALT */
 int sched_domain_level_max;
 
+#ifndef CONFIG_SCHED_ALT
 static int __init setup_relax_domain_level(char *str)
 {
 	if (kstrtoint(str, 0, &default_relax_domain_level))
@@ -1413,6 +1416,7 @@ sd_init(struct sched_domain_topology_level *tl,
 
 	return sd;
 }
+#endif /* CONFIG_SCHED_ALT */
 
 /*
  * Topology list, bottom-up.
@@ -1442,6 +1446,7 @@ void set_sched_topology(struct sched_domain_topology_level *tl)
 	sched_domain_topology = tl;
 }
 
+#ifndef CONFIG_SCHED_ALT
 #ifdef CONFIG_NUMA
 
 static const struct cpumask *sd_numa_mask(int cpu)
@@ -2316,3 +2321,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
 	partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
 	mutex_unlock(&sched_domains_mutex);
 }
+#else /* CONFIG_SCHED_ALT */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+			     struct sched_domain_attr *dattr_new)
+{}
+
+#ifdef CONFIG_NUMA
+int __read_mostly		node_reclaim_distance = RECLAIM_DISTANCE;
+
+int sched_numa_find_closest(const struct cpumask *cpus, int cpu)
+{
+	return best_mask_cpu(cpu, cpus);
+}
+#endif /* CONFIG_NUMA */
+#endif
diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index afad085960b8..e91b4cb3042b 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -120,6 +120,10 @@ static unsigned long long_max = LONG_MAX;
 static int one_hundred = 100;
 static int two_hundred = 200;
 static int one_thousand = 1000;
+#ifdef CONFIG_SCHED_ALT
+static int __maybe_unused zero = 0;
+extern int sched_yield_type;
+#endif
 #ifdef CONFIG_PRINTK
 static int ten_thousand = 10000;
 #endif
@@ -184,7 +188,7 @@ static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
 int sysctl_legacy_va_layout;
 #endif
 
-#ifdef CONFIG_SCHED_DEBUG
+#if defined(CONFIG_SCHED_DEBUG) && !defined(CONFIG_SCHED_ALT)
 static int min_sched_granularity_ns = 100000;		/* 100 usecs */
 static int max_sched_granularity_ns = NSEC_PER_SEC;	/* 1 second */
 static int min_wakeup_granularity_ns;			/* 0 usecs */
@@ -1652,6 +1656,7 @@ int proc_do_static_key(struct ctl_table *table, int write,
 }
 
 static struct ctl_table kern_table[] = {
+#ifndef CONFIG_SCHED_ALT
 	{
 		.procname	= "sched_child_runs_first",
 		.data		= &sysctl_sched_child_runs_first,
@@ -1854,6 +1859,7 @@ static struct ctl_table kern_table[] = {
 		.extra2		= SYSCTL_ONE,
 	},
 #endif
+#endif /* !CONFIG_SCHED_ALT */
 #ifdef CONFIG_PROVE_LOCKING
 	{
 		.procname	= "prove_locking",
@@ -2430,6 +2436,17 @@ static struct ctl_table kern_table[] = {
 		.proc_handler	= proc_dointvec,
 	},
 #endif
+#ifdef CONFIG_SCHED_ALT
+	{
+		.procname	= "yield_type",
+		.data		= &sched_yield_type,
+		.maxlen		= sizeof (int),
+		.mode		= 0644,
+		.proc_handler	= &proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &two,
+	},
+#endif
 #if defined(CONFIG_S390) && defined(CONFIG_SMP)
 	{
 		.procname	= "spin_retry",
diff --git a/kernel/time/hrtimer.c b/kernel/time/hrtimer.c
index 95b6a708b040..81f2ee62c807 100644
--- a/kernel/time/hrtimer.c
+++ b/kernel/time/hrtimer.c
@@ -1927,8 +1927,10 @@ long hrtimer_nanosleep(ktime_t rqtp, const enum hrtimer_mode mode,
 	int ret = 0;
 	u64 slack;
 
+#ifndef CONFIG_SCHED_ALT
 	slack = current->timer_slack_ns;
 	if (dl_task(current) || rt_task(current))
+#endif
 		slack = 0;
 
 	hrtimer_init_sleeper_on_stack(&t, clockid, mode);
diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c
index a71758e34e45..d20c347df861 100644
--- a/kernel/time/posix-cpu-timers.c
+++ b/kernel/time/posix-cpu-timers.c
@@ -216,7 +216,7 @@ static void task_sample_cputime(struct task_struct *p, u64 *samples)
 	u64 stime, utime;
 
 	task_cputime(p, &utime, &stime);
-	store_samples(samples, stime, utime, p->se.sum_exec_runtime);
+	store_samples(samples, stime, utime, tsk_seruntime(p));
 }
 
 static void proc_sample_cputime_atomic(struct task_cputime_atomic *at,
@@ -801,6 +801,7 @@ static void collect_posix_cputimers(struct posix_cputimers *pct, u64 *samples,
 	}
 }
 
+#ifndef CONFIG_SCHED_ALT
 static inline void check_dl_overrun(struct task_struct *tsk)
 {
 	if (tsk->dl.dl_overrun) {
@@ -808,6 +809,7 @@ static inline void check_dl_overrun(struct task_struct *tsk)
 		__group_send_sig_info(SIGXCPU, SEND_SIG_PRIV, tsk);
 	}
 }
+#endif
 
 static bool check_rlimit(u64 time, u64 limit, int signo, bool rt, bool hard)
 {
@@ -835,8 +837,10 @@ static void check_thread_timers(struct task_struct *tsk,
 	u64 samples[CPUCLOCK_MAX];
 	unsigned long soft;
 
+#ifndef CONFIG_SCHED_ALT
 	if (dl_task(tsk))
 		check_dl_overrun(tsk);
+#endif
 
 	if (expiry_cache_is_inactive(pct))
 		return;
@@ -850,7 +854,7 @@ static void check_thread_timers(struct task_struct *tsk,
 	soft = task_rlimit(tsk, RLIMIT_RTTIME);
 	if (soft != RLIM_INFINITY) {
 		/* Task RT timeout is accounted in jiffies. RTTIME is usec */
-		unsigned long rttime = tsk->rt.timeout * (USEC_PER_SEC / HZ);
+		unsigned long rttime = tsk_rttimeout(tsk) * (USEC_PER_SEC / HZ);
 		unsigned long hard = task_rlimit_max(tsk, RLIMIT_RTTIME);
 
 		/* At the hard limit, send SIGKILL. No further action. */
@@ -1086,8 +1090,10 @@ static inline bool fastpath_timer_check(struct task_struct *tsk)
 			return true;
 	}
 
+#ifndef CONFIG_SCHED_ALT
 	if (dl_task(tsk) && tsk->dl.dl_overrun)
 		return true;
+#endif
 
 	return false;
 }
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index b5e3496cf803..65f60c77bc50 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -1048,10 +1048,15 @@ static int trace_wakeup_test_thread(void *data)
 {
 	/* Make this a -deadline thread */
 	static const struct sched_attr attr = {
+#ifdef CONFIG_SCHED_ALT
+		/* No deadline on BMQ/PDS, use RR */
+		.sched_policy = SCHED_RR,
+#else
 		.sched_policy = SCHED_DEADLINE,
 		.sched_runtime = 100000ULL,
 		.sched_deadline = 10000000ULL,
 		.sched_period = 10000000ULL
+#endif
 	};
 	struct wakeup_test_data *x = data;
 
diff --git a/kernel/sched/alt_core.c b/kernel/sched/alt_core.c
index f36264fea75c6ca7c34eaa259c0bff829cbf6ac0..d43ca62fd00fe442bda9b4ad548fae432a7436de 100644
--- a/kernel/sched/alt_core.c
+++ b/kernel/sched/alt_core.c
@@ -11,6 +11,10 @@
  *		scheduler by Alfred Chen.
  *  2019-02-20	BMQ(BitMap Queue) kernel scheduler by Alfred Chen.
  */
+#define CREATE_TRACE_POINTS
+#include <trace/events/sched.h>
+#undef CREATE_TRACE_POINTS
+
 #include "sched.h"
 
 #include <linux/sched/rt.h>
@@ -42,8 +46,11 @@
 #include "pelt.h"
 #include "smp.h"
 
-#define CREATE_TRACE_POINTS
-#include <trace/events/sched.h>
+/*
+ * Export tracepoints that act as a bare tracehook (ie: have no trace event
+ * associated with them) to allow external modules to probe them.
+ */
+EXPORT_TRACEPOINT_SYMBOL_GPL(pelt_irq_tp);
 
 #define ALT_SCHED_VERSION "v5.9-r0"
 
diff --git a/kernel/sched/alt_sched.h b/kernel/sched/alt_sched.h
index 99be2c51c88d0406cced20b36d7230da12930a5c..03f8b8b1aa27eeb15989af25b4050c767da12aad 100644
--- a/kernel/sched/alt_sched.h
+++ b/kernel/sched/alt_sched.h
@@ -46,6 +46,8 @@
 
 #include "cpupri.h"
 
+#include <trace/events/sched.h>
+
 #ifdef CONFIG_SCHED_BMQ
 #include "bmq.h"
 #endif
@@ -496,6 +498,8 @@ static inline int sched_tick_offload_init(void) { return 0; }
 
 extern void schedule_idle(void);
 
+#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
+
 /*
  * !! For sched_setattr_nocheck() (kernel) only !!
  *