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SubjectRe: [PATCH] RIFS cpu scheduler
From
On Mon, Apr 23, 2012 at 9:13 PM, Hillf Danton <dhillf@gmail.com> wrote:
> On Mon, Apr 23, 2012 at 5:09 PM, mou Chen <hi3766691@gmail.com> wrote:
>> Here s the link of the cpu scheduler.
>> http://code.google.com/p/rifs-scheduler/downloads/list
>>
>> Patch the kernel firsrt, then replace the file /kernel/sched/rifs.c
>> with the new one that I attached.
>>
>> It is designed for interactivity and responsiveness. :-)
>>
> What is the relation between RIFS and BFS?

Also for a more newer version of RIFS you can download file that I
attached and replace it with the original file /kernel/sched/rifs.c
:)
/*
* kernel/sched/rifs.c
*
* Kernel scheduler and related syscalls
*
* Copyright (C) 1991-2002 Linus Torvalds
*
* 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
* make semaphores SMP safe
* 1998-11-19 Implemented schedule_timeout() and related stuff
* by Andrea Arcangeli
* 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
* hybrid priority-list and round-robin design with
* an array-switch method of distributing timeslices
* and per-CPU runqueues. Cleanups and useful suggestions
* by Davide Libenzi, preemptible kernel bits by Robert Love.
* 2003-09-03 Interactivity tuning by Con Kolivas.
* 2004-04-02 Scheduler domains code by Nick Piggin
* 2007-04-15 Work begun on replacing all interactivity tuning with a
* fair scheduling design by Con Kolivas.
* 2007-05-05 Load balancing (smp-nice) and other improvements
* by Peter Williams
* 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
* 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
* 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
* Thomas Gleixner, Mike Kravetz
* now *All the previous things were removed*
*
* Interactivity Tuning again by me.
*/

#include <linux/mm.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/highmem.h>
#include <asm/mmu_context.h>
#include <linux/interrupt.h>
#include <linux/capability.h>
#include <linux/completion.h>
#include <linux/kernel_stat.h>
#include <linux/debug_locks.h>
#include <linux/perf_event.h>
#include <linux/security.h>
#include <linux/notifier.h>
#include <linux/profile.h>
#include <linux/freezer.h>
#include <linux/vmalloc.h>
#include <linux/blkdev.h>
#include <linux/delay.h>
#include <linux/smp.h>
#include <linux/threads.h>
#include <linux/timer.h>
#include <linux/rcupdate.h>
#include <linux/cpu.h>
#include <linux/cpuset.h>
#include <linux/cpumask.h>
#include <linux/percpu.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/syscalls.h>
#include <linux/times.h>
#include <linux/tsacct_kern.h>
#include <linux/kprobes.h>
#include <linux/delayacct.h>
#include <linux/log2.h>
#include <linux/bootmem.h>
#include <linux/ftrace.h>
#include <linux/slab.h>
#include <linux/init_task.h>

#include <asm/tlb.h>
#include <asm/unistd.h>
#include <asm/mutex.h>
#ifdef CONFIG_PARAVIRT
#include <asm/paravirt.h>
#endif

#include "cpupri.h"
#include "../workqueue_sched.h"

#define CREATE_TRACE_POINTS
#include <trace/events/sched.h>

#define rt_prio(prio) unlikely((prio) < MAX_RT_PRIO)
#define rt_task(p) rt_prio((p)->prio)
#define rt_queue(rq) rt_prio((rq)->rq_prio)
#define batch_task(p) (unlikely((p)->policy == SCHED_BATCH))
#define is_rt_policy(policy) ((policy) == SCHED_FIFO || \
(policy) == SCHED_RR)
#define has_rt_policy(p) unlikely(is_rt_policy((p)->policy))
#define idleprio_task(p) unlikely((p)->policy == SCHED_IDLEPRIO)

/*
* Convert user-nice values [ -20 ... 0 ... 19 ]
* to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
* and back.
*/
#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
#define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
#define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)

/*
* 'User priority' is the nice value converted to something we
* can work with better when scaling various scheduler parameters,
* it's a [ 0 ... 39 ] range.
*/
#define USER_PRIO(p) ((p) - MAX_RT_PRIO)
#define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
#define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
#define SCHED_PRIO(p) ((p) + MAX_RT_PRIO)
#define STOP_PRIO (MAX_RT_PRIO - 1)

/*
* Some helpers for converting to/from various scales. Use shifts to get
* approximate multiples of ten for less overhead.
*/
#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ))
#define JIFFY_NS (1000000000 / HZ)
#define HALF_JIFFY_NS (1000000000 / HZ / 2)
#define HALF_JIFFY_US (1000000 / HZ / 2)
#define MS_TO_NS(TIME) ((TIME) << 20)
#define MS_TO_US(TIME) ((TIME) << 10)
#define NS_TO_MS(TIME) ((TIME) >> 20)
#define NS_TO_US(TIME) ((TIME) >> 10)

#define RESCHED_US (100) /* Reschedule if less than this many μs left */


/**
* print_scheduler_version(void)
*/
void print_scheduler_version(void)
{
printk(KERN_INFO "RIFS Scheduler\n");
}

/*
* This is the time all tasks within the same priority round robin.
* Value is in ms and set to a minimum of 6ms. Scales with number of cpus.
* Tunable via /proc interface.
*/
int rr_interval __read_mostly = 6;

/* Crap */
int sched_iso_cpu __read_mostly = 0;

/*
* The quota handed out to tasks of all priority levels when refilling their
* time_slice.
*/
static inline int timeslice(void)
{
return MS_TO_US(rr_interval);
}

/*
* The global runqueue data that all CPUs work off. Data is protected either
* by the global grq lock, or the discrete lock that precedes the data in this
* struct.
*/
struct global_rq {
raw_spinlock_t lock;
unsigned long nr_running;
unsigned long nr_uninterruptible;
unsigned long long nr_switches;
struct list_head queue[PRIO_LIMIT];
DECLARE_BITMAP(prio_bitmap, PRIO_LIMIT + 1);
#ifdef CONFIG_SMP
unsigned long qnr; /* queued not running */
cpumask_t cpu_idle_map;
bool idle_cpus;
#endif
int noc; /* num_online_cpus stored and updated when it changes */
u64 niffies; /* Nanosecond jiffies */
unsigned long last_jiffy; /* Last jiffy we updated niffies */
};

#ifdef CONFIG_SMP

/*
* We add the notion of a root-domain which will be used to define per-domain
* variables. Each exclusive cpuset essentially defines an island domain by
* fully partitioning the member cpus from any other cpuset. Whenever a new
* exclusive cpuset is created, we also create and attach a new root-domain
* object.
*
*/
struct root_domain {
atomic_t refcount;
atomic_t rto_count;
struct rcu_head rcu;
cpumask_var_t span;
cpumask_var_t online;

/*
* The "RT overload" flag: it gets set if a CPU has more than
* one runnable RT task.
*/
cpumask_var_t rto_mask;
struct cpupri cpupri;
};

/*
* By default the system creates a single root-domain with all cpus as
* members (mimicking the global state we have today).
*/
static struct root_domain def_root_domain;

#endif /* CONFIG_SMP */

/* There can be only one */
static struct global_rq grq;

/*
* This is the main, per-CPU runqueue data structure.
* This data should only be modified by the local cpu.
*/
struct rq {
#ifdef CONFIG_SMP
#ifdef CONFIG_NO_HZ
u64 nohz_stamp;
unsigned char in_nohz_recently;
#endif
#endif

struct task_struct *curr, *idle, *stop;
struct mm_struct *prev_mm;

unsigned int rq_policy;
int rq_time_slice;
u64 rq_last_ran;
int rq_prio;
bool rq_running; /* There is a task running */

/* Accurate timekeeping data */
u64 timekeep_clock;
unsigned long user_pc, nice_pc, irq_pc, softirq_pc, system_pc,
iowait_pc, idle_pc;
long account_pc;
atomic_t nr_iowait;

#ifdef CONFIG_SMP
int cpu; /* cpu of this runqueue */
bool online;
bool scaling; /* This CPU is managed by a scaling CPU freq governor */
struct task_struct *sticky_task;

struct root_domain *rd;
struct sched_domain *sd;
int *cpu_locality; /* CPU relative cache distance */
#ifdef CONFIG_SCHED_SMT
bool (*siblings_idle)(int cpu);
/* See if all smt siblings are idle */
cpumask_t smt_siblings;
#endif
#ifdef CONFIG_SCHED_MC
bool (*cache_idle)(int cpu);
/* See if all cache siblings are idle */
cpumask_t cache_siblings;
#endif
u64 last_niffy; /* Last time this RQ updated grq.niffies */
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
u64 prev_irq_time;
#endif
#ifdef CONFIG_PARAVIRT
u64 prev_steal_time;
#endif
#ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING
u64 prev_steal_time_rq;
#endif

u64 clock, old_clock, last_tick;
u64 clock_task;

#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
};

DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
static DEFINE_MUTEX(sched_hotcpu_mutex);

#ifdef CONFIG_SMP
/*
* sched_domains_mutex serialises calls to init_sched_domains,
* detach_destroy_domains and partition_sched_domains.
*/
static DEFINE_MUTEX(sched_domains_mutex);

/*
* By default the system creates a single root-domain with all cpus as
* members (mimicking the global state we have today).
*/
static struct root_domain def_root_domain;

int __weak arch_sd_sibling_asym_packing(void)
{
return 0*SD_ASYM_PACKING;
}
#endif

#define rcu_dereference_check_sched_domain(p) \
rcu_dereference_check((p), \
lockdep_is_held(&sched_domains_mutex))

/*
* The domain tree (rq->sd) is protected by RCU's quiescent state transition.
* See detach_destroy_domains: synchronize_sched for details.
*
* The domain tree of any CPU may only be accessed from within
* preempt-disabled sections.
*/
#define for_each_domain(cpu, __sd) \
for (__sd = rcu_dereference_check_sched_domain(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)

static inline void update_rq_clock(struct rq *rq);

/*
* Sanity check should sched_clock return bogus values. We make sure it does
* not appear to go backwards, and use jiffies to determine the maximum and
* minimum it could possibly have increased, and round down to the nearest
* jiffy when it falls outside this.
*/
static inline void niffy_diff(s64 *niff_diff, int jiff_diff)
{
unsigned long min_diff, max_diff;

if (jiff_diff > 1)
min_diff = JIFFIES_TO_NS(jiff_diff - 1);
else
min_diff = 1;
/* Round up to the nearest tick for maximum */
max_diff = JIFFIES_TO_NS(jiff_diff + 1);

if (unlikely(*niff_diff < min_diff || *niff_diff > max_diff))
*niff_diff = min_diff;
}

#ifdef CONFIG_SMP
#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
#define this_rq() (&__get_cpu_var(runqueues))
#define task_rq(p) cpu_rq(task_cpu(p))
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
static inline int cpu_of(struct rq *rq)
{
return rq->cpu;
}

/*
* Niffies are a globally increasing nanosecond counter. Whenever a runqueue
* clock is updated with the grq.lock held, it is an opportunity to update the
* niffies value. Any CPU can update it by adding how much its clock has
* increased since it last updated niffies, minus any added niffies by other
* CPUs.
*/
static inline void update_clocks(struct rq *rq)
{
s64 ndiff;
long jdiff;

update_rq_clock(rq);
ndiff = rq->clock - rq->old_clock;
/* old_clock is only updated when we are updating niffies */
rq->old_clock = rq->clock;
ndiff -= grq.niffies - rq->last_niffy;
jdiff = jiffies - grq.last_jiffy;
niffy_diff(&ndiff, jdiff);
grq.last_jiffy += jdiff;
grq.niffies += ndiff;
rq->last_niffy = grq.niffies;
}
#else /* CONFIG_SMP */
static struct rq *uprq;
#define cpu_rq(cpu) (uprq)
#define this_rq() (uprq)
#define task_rq(p) (uprq)
#define cpu_curr(cpu) ((uprq)->curr)
static inline int cpu_of(struct rq *rq)
{
return 0;
}

static inline void update_clocks(struct rq *rq)
{
s64 ndiff;
long jdiff;

update_rq_clock(rq);
ndiff = rq->clock - rq->old_clock;
rq->old_clock = rq->clock;
jdiff = jiffies - grq.last_jiffy;
niffy_diff(&ndiff, jdiff);
grq.last_jiffy += jdiff;
grq.niffies += ndiff;
}
#endif
#define raw_rq() (&__raw_get_cpu_var(runqueues))

#include "stats.h"

#ifndef prepare_arch_switch
# define prepare_arch_switch(next) do { } while (0)
#endif
#ifndef finish_arch_switch
# define finish_arch_switch(prev) do { } while (0)
#endif

/*
* All common locking functions performed on grq.lock. rq->clock is local to
* the CPU accessing it so it can be modified just with interrupts disabled
* when we're not updating niffies.
* Looking up task_rq must be done under grq.lock to be safe.
*/
static void update_rq_clock_task(struct rq *rq, s64 delta);

static inline void update_rq_clock(struct rq *rq)
{
s64 delta = sched_clock_cpu(cpu_of(rq)) - rq->clock;

rq->clock += delta;
update_rq_clock_task(rq, delta);
}

static inline bool task_running(struct task_struct *p)
{
return p->on_cpu;
}

static inline void grq_lock(void)
__acquires(grq.lock)
{
raw_spin_lock(&grq.lock);
}

static inline void grq_unlock(void)
__releases(grq.lock)
{
raw_spin_unlock(&grq.lock);
}

static inline void grq_lock_irq(void)
__acquires(grq.lock)
{
raw_spin_lock_irq(&grq.lock);
}

static inline void time_lock_grq(struct rq *rq)
__acquires(grq.lock)
{
grq_lock();
update_clocks(rq);
}

static inline void grq_unlock_irq(void)
__releases(grq.lock)
{
raw_spin_unlock_irq(&grq.lock);
}

static inline void grq_lock_irqsave(unsigned long *flags)
__acquires(grq.lock)
{
raw_spin_lock_irqsave(&grq.lock, *flags);
}

static inline void grq_unlock_irqrestore(unsigned long *flags)
__releases(grq.lock)
{
raw_spin_unlock_irqrestore(&grq.lock, *flags);
}

static inline struct rq
*task_grq_lock(struct task_struct *p, unsigned long *flags)
__acquires(grq.lock)
{
grq_lock_irqsave(flags);
return task_rq(p);
}

static inline struct rq
*time_task_grq_lock(struct task_struct *p, unsigned long *flags)
__acquires(grq.lock)
{
struct rq *rq = task_grq_lock(p, flags);
update_clocks(rq);
return rq;
}

static inline struct rq *task_grq_lock_irq(struct task_struct *p)
__acquires(grq.lock)
{
grq_lock_irq();
return task_rq(p);
}

static inline void time_task_grq_lock_irq(struct task_struct *p)
__acquires(grq.lock)
{
struct rq *rq = task_grq_lock_irq(p);
update_clocks(rq);
}

static inline void task_grq_unlock_irq(void)
__releases(grq.lock)
{
grq_unlock_irq();
}

static inline void task_grq_unlock(unsigned long *flags)
__releases(grq.lock)
{
grq_unlock_irqrestore(flags);
}

/**
* grunqueue_is_locked
*
* Returns true if the global runqueue is locked.
* This interface allows printk to be called with the runqueue lock
* held and know whether or not it is OK to wake up the klogd.
*/
bool grunqueue_is_locked(void)
{
return raw_spin_is_locked(&grq.lock);
}

void grq_unlock_wait(void)
__releases(grq.lock)
{
smp_mb(); /* spin-unlock-wait is not a full memory barrier */
raw_spin_unlock_wait(&grq.lock);
}

static inline void time_grq_lock(struct rq *rq, unsigned long *flags)
__acquires(grq.lock)
{
local_irq_save(*flags);
time_lock_grq(rq);
}

static inline struct rq *__task_grq_lock(struct task_struct *p)
__acquires(grq.lock)
{
grq_lock();
return task_rq(p);
}

static inline void __task_grq_unlock(void)
__releases(grq.lock)
{
grq_unlock();
}

/*
* Look for any tasks *anywhere* that are running nice 0 or better. We do
* this lockless for overhead reasons since the occasional wrong result
* is harmless.
*/
bool above_background_load(void)
{
int cpu;

for_each_online_cpu(cpu) {
struct task_struct *cpu_curr = cpu_rq(cpu)->curr;

if (unlikely(!cpu_curr))
continue;
if (PRIO_TO_NICE(cpu_curr->static_prio) < 1) {
return true;
}
}
return false;
}

#ifndef __ARCH_WANT_UNLOCKED_CTXSW
static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
{
}

static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
{
#ifdef CONFIG_DEBUG_SPINLOCK
/* this is a valid case when another task releases the spinlock */
grq.lock.owner = current;
#endif
/*
* 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(&grq.lock.dep_map, 0, 0, _THIS_IP_);

grq_unlock_irq();
}

#else /* __ARCH_WANT_UNLOCKED_CTXSW */

static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
{
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
grq_unlock_irq();
#else
grq_unlock();
#endif
}

static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
{
smp_wmb();
#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
local_irq_enable();
#endif
}
#endif /* __ARCH_WANT_UNLOCKED_CTXSW */

/*
* A task that is queued but not running will be on the grq run list.
* A task that is not running or queued will not be on the grq run list.
* A task that is currently running will have ->on_cpu set but not on the
* grq run list.
*/
static inline bool task_queued(struct task_struct *p)
{
return (!list_empty(&p->run_list));
}

/*
* Removing from the global runqueue. Enter with grq locked.
*/
static void dequeue_task(struct task_struct *p)
{
list_del_init(&p->run_list);
if (list_empty(grq.queue + p->prio))
__clear_bit(p->prio, grq.prio_bitmap);
}

/*
* Adding to the global runqueue. Enter with grq locked.
*/
static void enqueue_task(struct task_struct *p)
{
__set_bit(p->prio, grq.prio_bitmap);
list_add_tail(&p->run_list, grq.queue + p->prio);
sched_info_queued(p);
}

/* Only idle task does this as a real time task*/
static inline void enqueue_task_head(struct task_struct *p)
{
__set_bit(p->prio, grq.prio_bitmap);
list_add(&p->run_list, grq.queue + p->prio);
sched_info_queued(p);
}

static inline void requeue_task(struct task_struct *p)
{
sched_info_queued(p);
}

#ifdef CONFIG_SMP
/*
* qnr is the "queued but not running" count which is the total number of
* tasks on the global runqueue list waiting for cpu time but not actually
* currently running on a cpu.
*/
static inline void inc_qnr(void)
{
grq.qnr++;
}

static inline void dec_qnr(void)
{
grq.qnr--;
}

static inline int queued_notrunning(void)
{
return grq.qnr;
}

/*
* The cpu_idle_map stores a bitmap of all the CPUs currently idle to
* allow easy lookup of whether any suitable idle CPUs are available.
* It's cheaper to maintain a binary yes/no if there are any idle CPUs on the
* idle_cpus variable than to do a full bitmask check when we are busy.
*/
static inline void set_cpuidle_map(int cpu)
{
if (likely(cpu_online(cpu))) {
cpu_set(cpu, grq.cpu_idle_map);
grq.idle_cpus = true;
}
}

static inline void clear_cpuidle_map(int cpu)
{
cpu_clear(cpu, grq.cpu_idle_map);
if (cpus_empty(grq.cpu_idle_map))
grq.idle_cpus = false;
}

static bool suitable_idle_cpus(struct task_struct *p)
{
if (!grq.idle_cpus)
return false;
return (cpus_intersects(p->cpus_allowed, grq.cpu_idle_map));
}

#define CPUIDLE_DIFF_THREAD (1)
#define CPUIDLE_DIFF_CORE (2)
#define CPUIDLE_CACHE_BUSY (4)
#define CPUIDLE_DIFF_CPU (8)
#define CPUIDLE_THREAD_BUSY (16)
#define CPUIDLE_DIFF_NODE (32)

static void resched_task(struct task_struct *p);

/*
* The best idle CPU is chosen according to the CPUIDLE ranking above where the
* lowest value would give the most suitable CPU to schedule p onto next. The
* order works out to be the following:
*
* Same core, idle or busy cache, idle or busy threads
* Other core, same cache, idle or busy cache, idle threads.
* Same node, other CPU, idle cache, idle threads.
* Same node, other CPU, busy cache, idle threads.
* Other core, same cache, busy threads.
* Same node, other CPU, busy threads.
* Other node, other CPU, idle cache, idle threads.
* Other node, other CPU, busy cache, idle threads.
* Other node, other CPU, busy threads.
*/
static void
resched_best_mask(int best_cpu, struct rq *rq, cpumask_t *tmpmask)
{
unsigned int best_ranking = CPUIDLE_DIFF_NODE | CPUIDLE_THREAD_BUSY |
CPUIDLE_DIFF_CPU | CPUIDLE_CACHE_BUSY | CPUIDLE_DIFF_CORE |
CPUIDLE_DIFF_THREAD;
int cpu_tmp;

if (cpu_isset(best_cpu, *tmpmask))
goto out;

for_each_cpu_mask(cpu_tmp, *tmpmask) {
unsigned int ranking;
struct rq *tmp_rq;

ranking = 0;
tmp_rq = cpu_rq(cpu_tmp);

#ifdef CONFIG_NUMA
if (rq->cpu_locality[cpu_tmp] > 3)
ranking |= CPUIDLE_DIFF_NODE;
else
#endif
if (rq->cpu_locality[cpu_tmp] > 2)
ranking |= CPUIDLE_DIFF_CPU;
#ifdef CONFIG_SCHED_MC
if (rq->cpu_locality[cpu_tmp] == 2)
ranking |= CPUIDLE_DIFF_CORE;
if (!(tmp_rq->cache_idle(cpu_tmp)))
ranking |= CPUIDLE_CACHE_BUSY;
#endif
#ifdef CONFIG_SCHED_SMT
if (rq->cpu_locality[cpu_tmp] == 1)
ranking |= CPUIDLE_DIFF_THREAD;
if (!(tmp_rq->siblings_idle(cpu_tmp)))
ranking |= CPUIDLE_THREAD_BUSY;
#endif
if (ranking < best_ranking) {
best_cpu = cpu_tmp;
best_ranking = ranking;
}
}
out:
resched_task(cpu_rq(best_cpu)->curr);
}

static void resched_best_idle(struct task_struct *p)
{
cpumask_t tmpmask;

cpus_and(tmpmask, p->cpus_allowed, grq.cpu_idle_map);
resched_best_mask(task_cpu(p), task_rq(p), &tmpmask);
}

static inline void resched_suitable_idle(struct task_struct *p)
{
if (suitable_idle_cpus(p))
resched_best_idle(p);
}
/*
* Flags to tell us whether this CPU is running a CPU frequency governor that
* has slowed its speed or not. No locking required as the very rare wrongly
* read value would be harmless.
*/
void cpu_scaling(int cpu)
{
cpu_rq(cpu)->scaling = true;
}

void cpu_nonscaling(int cpu)
{
cpu_rq(cpu)->scaling = false;
}

static inline bool scaling_rq(struct rq *rq)
{
return rq->scaling;
}

static inline int locality_diff(struct task_struct *p, struct rq *rq)
{
return rq->cpu_locality[task_cpu(p)];
}
#else /* CONFIG_SMP */
static inline void inc_qnr(void)
{
}

static inline void dec_qnr(void)
{
}

static inline int queued_notrunning(void)
{
return grq.nr_running;
}

static inline void set_cpuidle_map(int cpu)
{
}

static inline void clear_cpuidle_map(int cpu)
{
}

static inline bool suitable_idle_cpus(struct task_struct *p)
{
return uprq->curr == uprq->idle;
}

static inline void resched_suitable_idle(struct task_struct *p)
{
}

void cpu_scaling(int __unused)
{
}

void cpu_nonscaling(int __unused)
{
}

/*
* Although CPUs can scale in UP, there is nowhere else for tasks to go so this
* always returns 0.
*/
static inline bool scaling_rq(struct rq *rq)
{
return false;
}

static inline int locality_diff(struct task_struct *p, struct rq *rq)
{
return 0;
}
#endif /* CONFIG_SMP */
EXPORT_SYMBOL_GPL(cpu_scaling);
EXPORT_SYMBOL_GPL(cpu_nonscaling);

/*
* activate_idle_task - move idle task to the _front_ of runqueue.
*/
static inline void activate_idle_task(struct task_struct *p)
{
enqueue_task_head(p);
grq.nr_running++;
inc_qnr();
}

static inline int normal_prio(struct task_struct *p)
{
if (has_rt_policy(p))
return MAX_RT_PRIO - 1 - p->rt_priority;
if (idleprio_task(p))
return IDLE_PRIO;
return p->normal_prio;
}

/*
* activate_task - move a task to the runqueue. Enter with grq locked.
*/
static void activate_task(struct task_struct *p, struct rq *rq, int preempt)
{
update_clocks(rq);

/*
* Sleep time is in units of nanosecs, so shift by 20 to get a
* milliseconds-range estimation of the amount of time that the task
* spent sleeping:
*/
if (unlikely(prof_on == SLEEP_PROFILING)) {
if (p->state == TASK_UNINTERRUPTIBLE)
profile_hits(SLEEP_PROFILING, (void *)get_wchan(p),
(rq->clock - p->last_ran) >> 20);
}

if (task_contributes_to_load(p))
grq.nr_uninterruptible--;
if(preempt) {
enqueue_task_head(p);
}else {
enqueue_task(p);
}
grq.nr_running++;
inc_qnr();
}

static inline void clear_sticky(struct task_struct *p);

/*
* deactivate_task - If it's running, it's not on the grq and we can just
* decrement the nr_running. Enter with grq locked.
*/
static inline void deactivate_task(struct task_struct *p)
{
if (task_contributes_to_load(p))
grq.nr_uninterruptible++;
grq.nr_running--;
clear_sticky(p);
}

#ifdef CONFIG_SMP
void set_task_cpu(struct task_struct *p, unsigned int cpu)
{
#ifdef CONFIG_LOCKDEP
/*
* The caller should hold grq lock.
*/
WARN_ON_ONCE(debug_locks && !lockdep_is_held(&grq.lock));
#endif
trace_sched_migrate_task(p, cpu);
if (task_cpu(p) != cpu)
perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);

/*
* After ->cpu is set up to a new value, task_grq_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();
task_thread_info(p)->cpu = cpu;
}

static inline void clear_sticky(struct task_struct *p)
{
p->sticky = false;
}

static inline bool task_sticky(struct task_struct *p)
{
return p->sticky;
}

/* Reschedule the best idle CPU that is not this one. */
static void
resched_closest_idle(struct rq *rq, int cpu, struct task_struct *p)
{
cpumask_t tmpmask;

cpus_and(tmpmask, p->cpus_allowed, grq.cpu_idle_map);
cpu_clear(cpu, tmpmask);
if (cpus_empty(tmpmask))
return;
resched_best_mask(cpu, rq, &tmpmask);
}

/*
* We set the sticky flag on a task that is descheduled involuntarily meaning
* it is awaiting further CPU time. If the last sticky task is still sticky
* but unlucky enough to not be the next task scheduled, we unstick it and try
* to find it an idle CPU. Realtime tasks do not stick to minimise their
* latency at all times.
*/
static inline void
swap_sticky(struct rq *rq, int cpu, struct task_struct *p)
{
if (rq->sticky_task) {
if (rq->sticky_task == p) {
p->sticky = true;
return;
}
if (task_sticky(rq->sticky_task)) {
clear_sticky(rq->sticky_task);
resched_closest_idle(rq, cpu, rq->sticky_task);
}
}
if (!rt_task(p)) {
p->sticky = true;
rq->sticky_task = p;
} else {
resched_closest_idle(rq, cpu, p);
rq->sticky_task = NULL;
}
}

static inline void unstick_task(struct rq *rq, struct task_struct *p)
{
rq->sticky_task = NULL;
clear_sticky(p);
}
#else
static inline void clear_sticky(struct task_struct *p)
{
}

static inline bool task_sticky(struct task_struct *p)
{
return false;
}

static inline void
swap_sticky(struct rq *rq, int cpu, struct task_struct *p)
{
}

static inline void unstick_task(struct rq *rq, struct task_struct *p)
{
}
#endif

/*
* resched_task - mark a 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.
*/
#ifdef CONFIG_SMP

#ifndef tsk_is_polling
#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
#endif

static void resched_task(struct task_struct *p)
{
int cpu;

assert_raw_spin_locked(&grq.lock);

if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
return;

set_tsk_thread_flag(p, TIF_NEED_RESCHED);

cpu = task_cpu(p);
if (cpu == smp_processor_id())
return;

/* NEED_RESCHED must be visible before we test polling */
smp_mb();
if (!tsk_is_polling(p))
smp_send_reschedule(cpu);
}

#else
static inline void resched_task(struct task_struct *p)
{
assert_raw_spin_locked(&grq.lock);
set_tsk_need_resched(p);
}
#endif

/**
* task_curr - is this task currently executing on a CPU?
* @p: the task in question.
*/
inline int task_curr(const struct task_struct *p)
{
return cpu_curr(task_cpu(p)) == p;
}

#ifdef CONFIG_SMP
struct migration_req {
struct task_struct *task;
int dest_cpu;
};

/*
* 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;

for (;;) {
/*
* We do the initial early heuristics without holding
* any task-queue locks at all. We'll only try to get
* the runqueue lock when things look like they will
* work out! In the unlikely event rq is dereferenced
* since we're lockless, grab it again.
*/
#ifdef CONFIG_SMP
retry_rq:
rq = task_rq(p);
if (unlikely(!rq))
goto retry_rq;
#else /* CONFIG_SMP */
rq = task_rq(p);
#endif
/*
* 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 grq
* lock now, to be *sure*. If we're wrong, we'll
* just go back and repeat.
*/
rq = task_grq_lock(p, &flags);
trace_sched_wait_task(p);
running = task_running(p);
on_rq = task_queued(p);
ncsw = 0;
if (!match_state || p->state == match_state)
ncsw = p->nvcsw | LONG_MIN; /* sets MSB */
task_grq_unlock(&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 = ktime_set(0, 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);
#endif

#define rq_idle(rq) ((rq)->rq_prio == PRIO_LIMIT)

/*
* RT tasks and NORMAL tasks preempt purely on priority.
* SCHED_IDLEPRIO don't preempt anything else or
* between themselves, they cooperatively multitask. An idle rq scores as
* prio PRIO_LIMIT so it is always preempted.
*/
static inline bool
can_preempt(struct task_struct *p, int prio)
{
/* Better static priority RT task or better policy preemption */
if (p->prio <= prio)
return true;
if (p->prio > prio)
return false;
return true;
}

#ifdef CONFIG_SMP
#ifdef CONFIG_HOTPLUG_CPU
/*
* Check to see if there is a task that is affined only to offline CPUs but
* still wants runtime. This happens to kernel threads during suspend/halt and
* disabling of CPUs.
*/
static inline bool online_cpus(struct task_struct *p)
{
return (likely(cpus_intersects(cpu_online_map, p->cpus_allowed)));
}
#else /* CONFIG_HOTPLUG_CPU */
/* All available CPUs are always online without hotplug. */
static inline bool online_cpus(struct task_struct *p)
{
return true;
}
#endif

/*
* Check to see if p can run on cpu, and if not, whether there are any online
* CPUs it can run on instead.
*/
static inline bool needs_other_cpu(struct task_struct *p, int cpu)
{
if (unlikely(!cpu_isset(cpu, p->cpus_allowed)))
return true;
return false;
}

/*
* When all else is equal, still prefer this_rq.
*/
static int try_preempt(struct task_struct *p, struct rq *this_rq)
{
int ret = 0;
struct rq *highest_prio_rq = NULL;
int cpu, highest_prio = 0;
cpumask_t tmp;

/*
* We clear the sticky flag here because for a task to have called
* try_preempt with the sticky flag enabled means some complicated
* re-scheduling has occurred and we should ignore the sticky flag.
*/
clear_sticky(p);

if (suitable_idle_cpus(p)) {
resched_best_idle(p);
return 1;
}

/* IDLEPRIO tasks never preempt anything but idle */
if (p->policy == SCHED_IDLEPRIO)
return 0;

if (likely(online_cpus(p)))
cpus_and(tmp, cpu_online_map, p->cpus_allowed);
else
return 0;

for_each_cpu_mask(cpu, tmp) {
struct rq *rq;
int rq_prio;

rq = cpu_rq(cpu);
rq_prio = rq->rq_prio;
if (rq_prio < highest_prio)
continue;

if (rq_prio > highest_prio) {
highest_prio = rq_prio;
highest_prio_rq = rq;
}
}

if (likely(highest_prio_rq)) {
if (can_preempt(p, highest_prio)) {
highest_prio_rq->curr->preempt = 1;
resched_task(highest_prio_rq->curr);
ret = 1;
}
}
return ret;
}
#else /* CONFIG_SMP */
static inline bool needs_other_cpu(struct task_struct *p, int cpu)
{
return false;
}

static int try_preempt(struct task_struct *p, struct rq *this_rq)
{
if (p->policy == SCHED_IDLEPRIO)
return 0;
if (can_preempt(p, uprq->rq_prio)) {
resched_task(uprq->curr);
return 1;
}
return 0;
}
#endif /* CONFIG_SMP */

static void
ttwu_stat(struct task_struct *p, int cpu, int wake_flags)
{
#ifdef CONFIG_SCHEDSTATS
struct rq *rq = this_rq();

#ifdef CONFIG_SMP
int this_cpu = smp_processor_id();

if (cpu == this_cpu)
schedstat_inc(rq, ttwu_local);
else {
struct sched_domain *sd;

rcu_read_lock();
for_each_domain(this_cpu, sd) {
if (cpumask_test_cpu(cpu, sched_domain_span(sd))) {
schedstat_inc(sd, ttwu_wake_remote);
break;
}
}
rcu_read_unlock();
}

#endif /* CONFIG_SMP */

schedstat_inc(rq, ttwu_count);
#endif /* CONFIG_SCHEDSTATS */
}

static inline void ttwu_activate(struct task_struct *p, struct rq *rq,
bool is_sync)
{
activate_task(p, rq, 1);

/*
* Sync wakeups (i.e. those types of wakeups where the waker
* has indicated that it will leave the CPU in short order)
* don't trigger a preemption if there are no idle cpus,
* instead waiting for current to deschedule.
*/
if (!is_sync || suitable_idle_cpus(p))
if(!try_preempt(p, rq)) {
dequeue_task(p);
enqueue_task(p);
}
}

static inline void ttwu_post_activation(struct task_struct *p, struct rq *rq,
bool success)
{
trace_sched_wakeup(p, success);
p->state = TASK_RUNNING;

/*
* if a worker is waking up, notify workqueue. Note that on BFS, we
* don't really know what cpu it will be, so we fake it for
* wq_worker_waking_up :/
*/
if ((p->flags & PF_WQ_WORKER) && success)
wq_worker_waking_up(p, cpu_of(rq));
}

#ifdef CONFIG_SMP
void scheduler_ipi(void)
{
}
#endif /* CONFIG_SMP */

/***
* 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_*)
*
* Put it on the run-queue if it's not already there. The "current"
* thread is always on the run-queue (except when the actual
* re-schedule is in progress), and as such you're allowed to do
* the simpler "current->state = TASK_RUNNING" to mark yourself
* runnable without the overhead of this.
*
* Returns %true if @p was woken up, %false if it was already running
* or @state didn't match @p's state.
*/
static bool try_to_wake_up(struct task_struct *p, unsigned int state,
int wake_flags)
{
bool success = false;
unsigned long flags;
struct rq *rq;
int cpu;

get_cpu();

/* This barrier is undocumented, probably for p->state? ?\8F\E3? */
smp_wmb();

/*
* No need to do time_lock_grq as we only need to update the rq clock
* if we activate the task
*/
rq = task_grq_lock(p, &flags);
cpu = task_cpu(p);

/* state is a volatile long, ?\A9\E3??\97て?\81\E5??\8B\E3??\AA\E3? */
if (!((unsigned int)p->state & state))
goto out_unlock;

if (task_queued(p) || task_running(p))
goto out_running;

ttwu_activate(p, rq, wake_flags & WF_SYNC);
success = true;

out_running:
ttwu_post_activation(p, rq, success);
out_unlock:
task_grq_unlock(&flags);

ttwu_stat(p, cpu, wake_flags);

put_cpu();

return success;
}

/**
* try_to_wake_up_local - try to wake up a local task with grq lock held
* @p: the thread to be awakened
*
* Put @p on the run-queue if it's not already there. The caller must
* ensure that grq is locked and, @p is not the current task.
* grq stays locked over invocation.
*/
static void try_to_wake_up_local(struct task_struct *p)
{
struct rq *rq = task_rq(p);
bool success = false;

lockdep_assert_held(&grq.lock);

if (!(p->state & TASK_NORMAL))
return;

if (!task_queued(p)) {
if (likely(!task_running(p))) {
schedstat_inc(rq, ttwu_count);
schedstat_inc(rq, ttwu_local);
}
ttwu_activate(p, rq, false);
ttwu_stat(p, smp_processor_id(), 0);
success = true;
}
ttwu_post_activation(p, rq, success);
}

/**
* 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. Returns 1 if the process was woken up, 0 if it was already
* running.
*
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
int wake_up_process(struct task_struct *p)
{
return try_to_wake_up(p, TASK_ALL, 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);
}

static void get_time_slice(struct task_struct *p);

/*
* Perform scheduler related setup for a newly forked process p.
* p is forked by current.
*/
void sched_fork(struct task_struct *p)
{
struct task_struct *curr;
int cpu = get_cpu();
struct rq *rq;

#ifdef CONFIG_PREEMPT_NOTIFIERS
INIT_HLIST_HEAD(&p->preempt_notifiers);
#endif
/*
* We mark the process as running 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_RUNNING;
set_task_cpu(p, cpu);

/* Should be reset in fork.c but done here for ease of bfs patching */
p->sched_time = p->stime_pc = p->utime_pc = 0;

/*
* Revert to default priority/policy on fork if requested.
*/
if (unlikely(p->sched_reset_on_fork)) {
if (p->policy == SCHED_FIFO || p->policy == SCHED_RR) {
p->policy = SCHED_NORMAL;
p->normal_prio = normal_prio(p);
}

if (PRIO_TO_NICE(p->static_prio) < 0) {
p->static_prio = NICE_TO_PRIO(0);
p->normal_prio = p->static_prio;
}

/*
* We don't need the reset flag anymore after the fork. It has
* fulfilled its duty:
*/
p->sched_reset_on_fork = 0;
}

curr = current;
/*
* Make sure we do not leak PI boosting priority to the child.
*/
p->prio = curr->normal_prio;

INIT_LIST_HEAD(&p->run_list);
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
if (unlikely(sched_info_on()))
memset(&p->sched_info, 0, sizeof(p->sched_info));
#endif

p->on_cpu = false;
clear_sticky(p);

#ifdef CONFIG_PREEMPT_COUNT
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
#endif
if (unlikely(p->policy == SCHED_FIFO))
goto out;
/*
* 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. If it's negative, it won't
* matter since that's the same as being 0. current's time_slice is
* actually in rq_time_slice when it's running, as is its last_ran
* value.
*/
rq = task_grq_lock_irq(curr);
if (likely(rq->rq_time_slice >= RESCHED_US * 2)) {
rq->rq_time_slice /= 2;
p->time_slice = rq->rq_time_slice;
} else {
/*
* Forking task has run out of timeslice. Reschedule it.
*/
rq->rq_time_slice = 0;
set_tsk_need_resched(curr);
get_time_slice(p);
}
p->last_ran = rq->rq_last_ran;
task_grq_unlock_irq();
out:
put_cpu();
}

/*
* 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)
{
struct task_struct *parent;
unsigned long flags;
struct rq *rq;

rq = task_grq_lock(p, &flags);
p->state = TASK_RUNNING;
parent = p->parent;
/* Unnecessary but small chance that the parent changed CPU */
set_task_cpu(p, task_cpu(parent));
activate_task(p, rq, 0);
trace_sched_wakeup_new(p, 1);
if (rq->curr == parent && !suitable_idle_cpus(p)) {
/*
* The VM isn't cloned, so we're in a good position to
* do child-runs-first in anticipation of an exec. This
* usually avoids a lot of COW overhead.
*/
resched_task(parent);
} else
try_preempt(p, rq);
task_grq_unlock(&flags);
}

#ifdef CONFIG_PREEMPT_NOTIFIERS

/**
* preempt_notifier_register - tell me when current is being preempted & rescheduled
* @notifier: notifier struct to register
*/
void preempt_notifier_register(struct preempt_notifier *notifier)
{
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 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;
struct hlist_node *node;

hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
notifier->ops->sched_in(notifier, raw_smp_processor_id());
}

static void
fire_sched_out_preempt_notifiers(struct task_struct *curr,
struct task_struct *next)
{
struct preempt_notifier *notifier;
struct hlist_node *node;

hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
notifier->ops->sched_out(notifier, next);
}

#else /* !CONFIG_PREEMPT_NOTIFIERS */

static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
{
}

static void
fire_sched_out_preempt_notifiers(struct task_struct *curr,
struct task_struct *next)
{
}

#endif /* CONFIG_PREEMPT_NOTIFIERS */

/**
* 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)
{
sched_info_switch(prev, next);
perf_event_task_sched_out(prev, next);
fire_sched_out_preempt_notifiers(prev, next);
prepare_lock_switch(rq, next);
prepare_arch_switch(next);
trace_sched_switch(prev, 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.)
*/
static inline void finish_task_switch(struct rq *rq, struct task_struct *prev)
__releases(grq.lock)
{
struct mm_struct *mm = rq->prev_mm;
long prev_state;

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.
* The test for TASK_DEAD must occur while the runqueue locks are
* still held, otherwise prev could be scheduled on another cpu, die
* there before we look at prev->state, and then the reference would
* be dropped twice.
* Manfred Spraul <manfred@colorfullife.com>
*/
prev_state = prev->state;
finish_arch_switch(prev);
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
local_irq_disable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
perf_event_task_sched_in(prev, current);
#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
local_irq_enable();
#endif /* __ARCH_WANT_INTERRUPTS_ON_CTXSW */
finish_lock_switch(rq, prev);

fire_sched_in_preempt_notifiers(current);
if (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);
put_task_struct(prev);
}
}

/**
* schedule_tail - first thing a freshly forked thread must call.
* @prev: the thread we just switched away from.
*/
asmlinkage void schedule_tail(struct task_struct *prev)
__releases(grq.lock)
{
struct rq *rq = this_rq();

finish_task_switch(rq, prev);
#ifdef __ARCH_WANT_UNLOCKED_CTXSW
/* In this case, finish_task_switch does not reenable preemption */
preempt_enable();
#endif
if (current->set_child_tid)
put_user(current->pid, current->set_child_tid);
}

/*
* context_switch - switch to the new MM and the new
* thread's register state.
*/
static inline void
context_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
struct mm_struct *mm, *oldmm;

prepare_task_switch(rq, prev, next);

mm = next->mm;
oldmm = prev->active_mm;
/*
* 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);

if (!mm) {
next->active_mm = oldmm;
atomic_inc(&oldmm->mm_count);
enter_lazy_tlb(oldmm, next);
} else
switch_mm(oldmm, mm, next);

if (!prev->mm) {
prev->active_mm = NULL;
rq->prev_mm = oldmm;
}
/*
* 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:
*/
#ifndef __ARCH_WANT_UNLOCKED_CTXSW
spin_release(&grq.lock.dep_map, 1, _THIS_IP_);
#endif

/* Here we just switch the register state and the stack. */
switch_to(prev, next, prev);

barrier();
/*
* this_rq must be evaluated again because prev may have moved
* CPUs since it called schedule(), thus the 'rq' on its stack
* frame will be invalid.
*/
finish_task_switch(this_rq(), prev);
}

/*
* nr_running, nr_uninterruptible and nr_context_switches:
*
* externally visible scheduler statistics: current number of runnable
* threads, current number of uninterruptible-sleeping threads, total
* number of context switches performed since bootup. All are measured
* without grabbing the grq lock but the occasional inaccurate result
* doesn't matter so long as it's positive.
*/
unsigned long nr_running(void)
{
long nr = grq.nr_running;

if (unlikely(nr < 0))
nr = 0;
return (unsigned long)nr;
}

unsigned long nr_uninterruptible(void)
{
long nu = grq.nr_uninterruptible;

if (unlikely(nu < 0))
nu = 0;
return nu;
}

unsigned long long nr_context_switches(void)
{
long long ns = grq.nr_switches;

/* This is of course impossible */
if (unlikely(ns < 0))
ns = 1;
return (unsigned long long)ns;
}

unsigned long nr_iowait(void)
{
unsigned long i, sum = 0;

for_each_possible_cpu(i)
sum += atomic_read(&cpu_rq(i)->nr_iowait);

return sum;
}

unsigned long nr_iowait_cpu(int cpu)
{
struct rq *this = cpu_rq(cpu);
return atomic_read(&this->nr_iowait);
}

unsigned long nr_active(void)
{
return nr_running() + nr_uninterruptible();
}

/* Beyond a task running on this CPU, load is equal everywhere on BFS */
unsigned long this_cpu_load(void)
{
return this_rq()->rq_running +
((queued_notrunning() + nr_uninterruptible()) / grq.noc);
}

/* Variables and functions for calc_load */
static unsigned long calc_load_update;
unsigned long avenrun[3];
EXPORT_SYMBOL(avenrun);

/**
* get_avenrun - get the load average array
* @loads: pointer to dest load array
* @offset: offset to add
* @shift: shift count to shift the result left
*
* These values are estimates at best, so no need for locking.
*/
void get_avenrun(unsigned long *loads, unsigned long offset, int shift)
{
loads[0] = (avenrun[0] + offset) << shift;
loads[1] = (avenrun[1] + offset) << shift;
loads[2] = (avenrun[2] + offset) << shift;
}

static unsigned long
calc_load(unsigned long load, unsigned long exp, unsigned long active)
{
load *= exp;
load += active * (FIXED_1 - exp);
return load >> FSHIFT;
}

/*
* calc_load - update the avenrun load estimates every LOAD_FREQ seconds.
*/
void calc_global_load(unsigned long ticks)
{
long active;

if (time_before(jiffies, calc_load_update))
return;
active = nr_active() * FIXED_1;

avenrun[0] = calc_load(avenrun[0], EXP_1, active);
avenrun[1] = calc_load(avenrun[1], EXP_5, active);
avenrun[2] = calc_load(avenrun[2], EXP_15, active);

calc_load_update = jiffies + LOAD_FREQ;
}

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);

#ifdef CONFIG_IRQ_TIME_ACCOUNTING

/*
* There are no locks covering percpu hardirq/softirq time.
* They are only modified in account_system_vtime, on corresponding CPU
* with interrupts disabled. So, writes are safe.
* They are read and saved off onto struct rq in update_rq_clock().
* This may result in other CPU reading this CPU's irq time and can
* race with irq/account_system_vtime on this CPU. We would either get old
* or new value with a side effect of accounting a slice of irq time to wrong
* task when irq is in progress while we read rq->clock. That is a worthy
* compromise in place of having locks on each irq in account_system_time.
*/
static DEFINE_PER_CPU(u64, cpu_hardirq_time);
static DEFINE_PER_CPU(u64, cpu_softirq_time);

static DEFINE_PER_CPU(u64, irq_start_time);
static int sched_clock_irqtime;

void enable_sched_clock_irqtime(void)
{
sched_clock_irqtime = 1;
}

void disable_sched_clock_irqtime(void)
{
sched_clock_irqtime = 0;
}

#ifndef CONFIG_64BIT
static DEFINE_PER_CPU(seqcount_t, irq_time_seq);

static inline void irq_time_write_begin(void)
{
__this_cpu_inc(irq_time_seq.sequence);
smp_wmb();
}

static inline void irq_time_write_end(void)
{
smp_wmb();
__this_cpu_inc(irq_time_seq.sequence);
}

static inline u64 irq_time_read(int cpu)
{
u64 irq_time;
unsigned seq;

do {
seq = read_seqcount_begin(&per_cpu(irq_time_seq, cpu));
irq_time = per_cpu(cpu_softirq_time, cpu) +
per_cpu(cpu_hardirq_time, cpu);
} while (read_seqcount_retry(&per_cpu(irq_time_seq, cpu), seq));

return irq_time;
}
#else /* CONFIG_64BIT */
static inline void irq_time_write_begin(void)
{
}

static inline void irq_time_write_end(void)
{
}

static inline u64 irq_time_read(int cpu)
{
return per_cpu(cpu_softirq_time, cpu) + per_cpu(cpu_hardirq_time, cpu);
}
#endif /* CONFIG_64BIT */

/*
* Called before incrementing preempt_count on {soft,}irq_enter
* and before decrementing preempt_count on {soft,}irq_exit.
*/
void account_system_vtime(struct task_struct *curr)
{
unsigned long flags;
s64 delta;
int cpu;

if (!sched_clock_irqtime)
return;

local_irq_save(flags);

cpu = smp_processor_id();
delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
__this_cpu_add(irq_start_time, delta);

irq_time_write_begin();
/*
* We do not account for softirq time from ksoftirqd here.
* We want to continue accounting softirq time to ksoftirqd thread
* in that case, so as not to confuse scheduler with a special task
* that do not consume any time, but still wants to run.
*/
if (hardirq_count())
__this_cpu_add(cpu_hardirq_time, delta);
else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
__this_cpu_add(cpu_softirq_time, delta);

irq_time_write_end();
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(account_system_vtime);

#endif /* CONFIG_IRQ_TIME_ACCOUNTING */

#ifdef CONFIG_PARAVIRT
static inline u64 steal_ticks(u64 steal)
{
if (unlikely(steal > NSEC_PER_SEC))
return div_u64(steal, TICK_NSEC);

return __iter_div_u64_rem(steal, TICK_NSEC, &steal);
}
#endif

static void update_rq_clock_task(struct rq *rq, s64 delta)
{
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
s64 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_branch((&paravirt_steal_rq_enabled))) {
u64 st, steal = paravirt_steal_clock(cpu_of(rq));

steal -= rq->prev_steal_time_rq;

if (unlikely(steal > delta))
steal = delta;

st = steal_ticks(steal);
steal = st * TICK_NSEC;

rq->prev_steal_time_rq += steal;

delta -= steal;
}
#endif

rq->clock_task += delta;
}

#ifndef nsecs_to_cputime
# define nsecs_to_cputime(__nsecs) nsecs_to_jiffies(__nsecs)
#endif

#ifdef CONFIG_IRQ_TIME_ACCOUNTING
static void irqtime_account_hi_si(void)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;
u64 latest_ns;

latest_ns = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time));
if (latest_ns > cpustat[CPUTIME_IRQ])
cpustat[CPUTIME_IRQ] += (__force u64)cputime_one_jiffy;

latest_ns = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time));
if (latest_ns > cpustat[CPUTIME_SOFTIRQ])
cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy;
}
#else /* CONFIG_IRQ_TIME_ACCOUNTING */

#define sched_clock_irqtime (0)

static inline void irqtime_account_hi_si(void)
{
}
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */

static __always_inline bool steal_account_process_tick(void)
{
#ifdef CONFIG_PARAVIRT
if (static_branch(&paravirt_steal_enabled)) {
u64 steal, st = 0;

steal = paravirt_steal_clock(smp_processor_id());
steal -= this_rq()->prev_steal_time;

st = steal_ticks(steal);
this_rq()->prev_steal_time += st * TICK_NSEC;

account_steal_time(st);
return st;
}
#endif
return false;
}

/*
* On each tick, see what percentage of that tick was attributed to each
* component and add the percentage to the _pc values. Once a _pc value has
* accumulated one tick's worth, account for that. This means the total
* percentage of load components will always be 128 (pseudo 100) per tick.
*/
static void pc_idle_time(struct rq *rq, unsigned long pc)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;

if (atomic_read(&rq->nr_iowait) > 0) {
rq->iowait_pc += pc;
if (rq->iowait_pc >= 128) {
rq->iowait_pc %= 128;
cpustat[CPUTIME_IOWAIT] += (__force u64)cputime_one_jiffy;
}
} else {
rq->idle_pc += pc;
if (rq->idle_pc >= 128) {
rq->idle_pc %= 128;
cpustat[CPUTIME_IDLE] += (__force u64)cputime_one_jiffy;
}
}
}

static void
pc_system_time(struct rq *rq, struct task_struct *p, int hardirq_offset,
unsigned long pc, unsigned long ns)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;
cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);

p->stime_pc += pc;
if (p->stime_pc >= 128) {
p->stime_pc %= 128;
p->stime += (__force u64)cputime_one_jiffy;
p->stimescaled += one_jiffy_scaled;
account_group_system_time(p, cputime_one_jiffy);
acct_update_integrals(p);
}
p->sched_time += ns;

if (hardirq_count() - hardirq_offset) {
rq->irq_pc += pc;
if (rq->irq_pc >= 128) {
rq->irq_pc %= 128;
cpustat[CPUTIME_IRQ] += (__force u64)cputime_one_jiffy;
}
} else if (in_serving_softirq()) {
rq->softirq_pc += pc;
if (rq->softirq_pc >= 128) {
rq->softirq_pc %= 128;
cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy;
}
} else {
rq->system_pc += pc;
if (rq->system_pc >= 128) {
rq->system_pc %= 128;
cpustat[CPUTIME_SYSTEM] += (__force u64)cputime_one_jiffy;
}
}
}

static void pc_user_time(struct rq *rq, struct task_struct *p,
unsigned long pc, unsigned long ns)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;
cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);

p->utime_pc += pc;
if (p->utime_pc >= 128) {
p->utime_pc %= 128;
p->utime += (__force u64)cputime_one_jiffy;
p->utimescaled += one_jiffy_scaled;
account_group_user_time(p, cputime_one_jiffy);
acct_update_integrals(p);
}
p->sched_time += ns;

if (this_cpu_ksoftirqd() == p) {
/*
* ksoftirqd time do not get accounted in cpu_softirq_time.
* So, we have to handle it separately here.
*/
rq->softirq_pc += pc;
if (rq->softirq_pc >= 128) {
rq->softirq_pc %= 128;
cpustat[CPUTIME_SOFTIRQ] += (__force u64)cputime_one_jiffy;
}
}

if (TASK_NICE(p) > 0 || idleprio_task(p)) {
rq->nice_pc += pc;
if (rq->nice_pc >= 128) {
rq->nice_pc %= 128;
cpustat[CPUTIME_NICE] += (__force u64)cputime_one_jiffy;
}
} else {
rq->user_pc += pc;
if (rq->user_pc >= 128) {
rq->user_pc %= 128;
cpustat[CPUTIME_USER] += (__force u64)cputime_one_jiffy;
}
}
}

/*
* Convert nanoseconds to pseudo percentage of one tick. Use 128 for fast
* shifts instead of 100
*/
#define NS_TO_PC(NS) (NS * 128 / JIFFY_NS)

/*
* This is called on clock ticks and on context switches.
* Bank in p->sched_time the ns elapsed since the last tick or switch.
* CPU scheduler quota accounting is also performed here in microseconds.
*/
static void
update_cpu_clock(struct rq *rq, struct task_struct *p, bool tick)
{
long account_ns = rq->clock - rq->timekeep_clock;
struct task_struct *idle = rq->idle;
unsigned long account_pc;

if (unlikely(account_ns < 0))
account_ns = 0;

p->time_slice = rq->rq_time_slice;
p->last_ran = rq->clock;

account_pc = NS_TO_PC(account_ns);

if (tick) {
int user_tick;

/* Accurate tick timekeeping */
rq->account_pc += account_pc - 128;
if (rq->account_pc < 0) {
/*
* Small errors in micro accounting may not make the
* accounting add up to 128 each tick so we keep track
* of the percentage and round it up when less than 128
*/
account_pc += -rq->account_pc;
rq->account_pc = 0;
}
if (steal_account_process_tick())
goto ts_account;

user_tick = user_mode(get_irq_regs());

if (user_tick)
pc_user_time(rq, p, account_pc, account_ns);
else if (p != idle || (irq_count() != HARDIRQ_OFFSET))
pc_system_time(rq, p, HARDIRQ_OFFSET,
account_pc, account_ns);
else
pc_idle_time(rq, account_pc);

if (sched_clock_irqtime)
irqtime_account_hi_si();
} else {
/* Accurate subtick timekeeping */
rq->account_pc += account_pc;
if (p == idle)
pc_idle_time(rq, account_pc);
else
pc_user_time(rq, p, account_pc, account_ns);
}

ts_account:
/* time_slice accounting is done in usecs to avoid overflow on 32bit */
if (rq->rq_policy != SCHED_FIFO && p != idle) {
s64 time_diff = rq->clock - rq->rq_last_ran;

niffy_diff(&time_diff, 1);
rq->rq_time_slice -= NS_TO_US(time_diff);
}
rq->rq_last_ran = rq->timekeep_clock = rq->clock;
}

/*
* Return any ns on the sched_clock that have not yet been accounted in
* @p in case that task is currently running.
*
* Called with task_grq_lock() held.
*/
static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
{
u64 ns = 0;

if (p == rq->curr) {
update_clocks(rq);
ns = rq->clock_task - rq->rq_last_ran;
if (unlikely((s64)ns < 0))
ns = 0;
}

return ns;
}

unsigned long long task_delta_exec(struct task_struct *p)
{
unsigned long flags;
struct rq *rq;
u64 ns;

rq = task_grq_lock(p, &flags);
ns = do_task_delta_exec(p, rq);
task_grq_unlock(&flags);

return ns;
}

/*
* Return accounted runtime for the task.
* In case the task is currently running, return the runtime plus 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;
u64 ns;

rq = task_grq_lock(p, &flags);
ns = p->sched_time + do_task_delta_exec(p, rq);
task_grq_unlock(&flags);

return ns;
}

/* Compatibility crap for removal */
void account_user_time(struct task_struct *p, cputime_t cputime,
cputime_t cputime_scaled)
{
}

void account_idle_time(cputime_t cputime)
{
}

/*
* Account guest cpu time to a process.
* @p: the process that the cpu time gets accounted to
* @cputime: the cpu time spent in virtual machine since the last update
* @cputime_scaled: cputime scaled by cpu frequency
*/
static void account_guest_time(struct task_struct *p, cputime_t cputime,
cputime_t cputime_scaled)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;

/* Add guest time to process. */
p->utime += (__force u64)cputime;
p->utimescaled += (__force u64)cputime_scaled;
account_group_user_time(p, cputime);
p->gtime += (__force u64)cputime;

/* Add guest time to cpustat. */
if (TASK_NICE(p) > 0) {
cpustat[CPUTIME_NICE] += (__force u64)cputime;
cpustat[CPUTIME_GUEST_NICE] += (__force u64)cputime;
} else {
cpustat[CPUTIME_USER] += (__force u64)cputime;
cpustat[CPUTIME_GUEST] += (__force u64)cputime;
}
}

/*
* Account system cpu time to a process and desired cpustat field
* @p: the process that the cpu time gets accounted to
* @cputime: the cpu time spent in kernel space since the last update
* @cputime_scaled: cputime scaled by cpu frequency
* @target_cputime64: pointer to cpustat field that has to be updated
*/
static inline
void __account_system_time(struct task_struct *p, cputime_t cputime,
cputime_t cputime_scaled, cputime64_t *target_cputime64)
{
/* Add system time to process. */
p->stime += (__force u64)cputime;
p->stimescaled += (__force u64)cputime_scaled;
account_group_system_time(p, cputime);

/* Add system time to cpustat. */
*target_cputime64 += (__force u64)cputime;

/* Account for system time used */
acct_update_integrals(p);
}

/*
* Account system cpu time to a process.
* @p: the process that the cpu time gets accounted to
* @hardirq_offset: the offset to subtract from hardirq_count()
* @cputime: the cpu time spent in kernel space since the last update
* @cputime_scaled: cputime scaled by cpu frequency
* This is for guest only now.
*/
void account_system_time(struct task_struct *p, int hardirq_offset,
cputime_t cputime, cputime_t cputime_scaled)
{

if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0))
account_guest_time(p, cputime, cputime_scaled);
}

/*
* Account for involuntary wait time.
* @steal: the cpu time spent in involuntary wait
*/
void account_steal_time(cputime_t cputime)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;

cpustat[CPUTIME_STEAL] += (__force u64)cputime;
}

/*
* Account for idle time.
* @cputime: the cpu time spent in idle wait
*/
static void account_idle_times(cputime_t cputime)
{
u64 *cpustat = kcpustat_this_cpu->cpustat;
struct rq *rq = this_rq();

if (atomic_read(&rq->nr_iowait) > 0)
cpustat[CPUTIME_IOWAIT] += (__force u64)cputime;
else
cpustat[CPUTIME_IDLE] += (__force u64)cputime;
}

#ifndef CONFIG_VIRT_CPU_ACCOUNTING

void account_process_tick(struct task_struct *p, int user_tick)
{
}

/*
* Account multiple ticks of steal time.
* @p: the process from which the cpu time has been stolen
* @ticks: number of stolen ticks
*/
void account_steal_ticks(unsigned long ticks)
{
account_steal_time(jiffies_to_cputime(ticks));
}

/*
* Account multiple ticks of idle time.
* @ticks: number of stolen ticks
*/
void account_idle_ticks(unsigned long ticks)
{
account_idle_times(jiffies_to_cputime(ticks));
}
#endif

/* This manages tasks that have run out of timeslice during a scheduler_tick */
/* 当\E5??\9F\E5??\B6\E9??\84控??*/
static void task_running_tick(struct rq *rq)
{
struct task_struct *p;

/* SCHED_FIFO tasks never run out of timeslice. */
if (rq->rq_policy == SCHED_FIFO)
return;

if (rq->rq_time_slice > RESCHED_US)
return;

/* p->time_slice < RESCHED_US. We only modify task_struct under grq lock */
p = rq->curr;
grq_lock();
requeue_task(p);
set_tsk_need_resched(p);
grq_unlock();
}

void wake_up_idle_cpu(int cpu);

/*
* This function gets called by the timer code, with HZ frequency.
* We call it with interrupts disabled. The data modified is all
* local to struct rq so we don't need to grab grq lock.
*/
void scheduler_tick(void)
{
int cpu __maybe_unused = smp_processor_id();
struct rq *rq = cpu_rq(cpu);

sched_clock_tick();
/* grq lock not grabbed, so only update rq clock */
update_rq_clock(rq);
update_cpu_clock(rq, rq->curr, true);
if (!rq_idle(rq))
task_running_tick(rq);
rq->last_tick = rq->clock;
perf_event_task_tick();
}

notrace unsigned long get_parent_ip(unsigned long addr)
{
if (in_lock_functions(addr)) {
addr = CALLER_ADDR2;
if (in_lock_functions(addr))
addr = CALLER_ADDR3;
}
return addr;
}

#if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
defined(CONFIG_PREEMPT_TRACER))
void __kprobes add_preempt_count(int val)
{
#ifdef CONFIG_DEBUG_PREEMPT
/*
* Underflow?
*/
if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
return;
#endif
preempt_count() += val;
#ifdef CONFIG_DEBUG_PREEMPT
/*
* Spinlock count overflowing soon?
*/
DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
PREEMPT_MASK - 10);
#endif
if (preempt_count() == val)
trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
}
EXPORT_SYMBOL(add_preempt_count);

void __kprobes sub_preempt_count(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

if (preempt_count() == val)
trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
preempt_count() -= val;
}
EXPORT_SYMBOL(sub_preempt_count);
#endif

/*
* Just refill.
*/
static inline void get_time_slice(struct task_struct *p)
{
p->time_slice = p->full_time_slice = timeslice();
}

static inline void priority_decrement(struct rq *rq, struct task_struct *p)
{
if(p->prio < p->static_prio) {
p->prio = p->static_prio;
}else {
p->prio += 2;
}

if(p->prio >= IDLE_PRIO) {
p->prio = p->static_prio;
}
get_time_slice(p);
}

static inline void priority_increment(struct rq *rq, struct task_struct *p)
{
/*
* The prev process is going to sleep. 如\E6?进\E7??\A1\E7?,剩余时?\B4\E7?大\E4?一?\8A\EF?增\E5?优\E5?级\E3\80?+ * Increase it's priority if it sleeps frequently.
*/
if((p->full_time_slice - rq->rq_time_slice) <= MS_TO_US(rr_interval / 2)) {

/*
* Make sure it is not being preempted. 确\E4?不是被抢?\A0\E3\80?+ */
if(!p->preempt) {
p->prio -= 2;

/*
* Get a time slice again. ?\8D次得到?\B6间?\87\E3\80?+ */
get_time_slice(p);
}else {
p->preempt = 0;
}
if((p->prio < NORMAL_PRIO) && (p->static_prio >= NORMAL_PRIO)) {
p->prio = NORMAL_PRIO;
}
if(p->prio <= 0) {
p->prio = 0;
}
}
}

/*
* Timeslices below RESCHED_US are considered as good as expired as there's no
* point rescheduling when there's so little time left. SCHED_BATCH tasks
* have been flagged be not latency sensitive and likely to be fully CPU
* bound so every time they're rescheduled they have their time_slice
* refilled.
*/
static inline void check_quantum_end(struct rq *rq, struct task_struct *p)
{
if (p->time_slice < RESCHED_US || batch_task(p)) {
priority_decrement(rq, p);
}else {
priority_increment(rq, p);
}
}

#define BITOP_WORD(nr) ((nr) / BITS_PER_LONG)

/*
* Move a task off the global queue and take it to a cpu for it will
* become the running task.
*/
static inline void take_task(int cpu, struct task_struct *p)
{
set_task_cpu(p, cpu);
dequeue_task(p);
clear_sticky(p);
dec_qnr();
}

/*
* Returns a descheduling task to the grq runqueue unless it is being
* deactivated.
*/
static inline void put_prev_task(struct rq *rq, struct task_struct *p, bool deactivate)
{
check_quantum_end(rq, p);
if (deactivate)
deactivate_task(p);
else {
inc_qnr();
enqueue_task(p);
}
}

/*
* Find the lowest bit set in the bitmap.We would find the highest priority first/
*/
static inline unsigned long
get_prio_bit(unsigned long *addr, unsigned long offset)
{
unsigned long *from = addr + (offset / BITS_PER_LONG);
unsigned long *limit = addr + PRIO_LIMIT / BITS_PER_LONG;
int i = offset % BITS_PER_LONG;

if (offset >= PRIO_LIMIT)
return PRIO_LIMIT;

for(;from != (limit);from++) {
for(;i < BITS_PER_LONG;i++, offset++) {
if(((*from >> i) & 0x1)) {
goto out;
}
}

/*
* This can make sure to generate the best machine code.
*/
i = 0;
}
out:
return offset;
}

/*
* All the things were thrown. It has become an O(1) operation again.
*/
static inline struct
task_struct *get_runnable_task(struct rq *rq, int cpu, struct task_struct *idle)
{
struct task_struct *edt = NULL;
unsigned long idx = -1;

do {
struct list_head *queue;
struct task_struct *p;

idx = get_prio_bit(grq.prio_bitmap, ++idx);
if (idx >= PRIO_LIMIT)
return idle;
queue = grq.queue + idx;

list_for_each_entry(p, queue, run_list) {
/* Make sure cpu affinity is ok */
if (needs_other_cpu(p, cpu))
continue;
edt = p;
goto out_take;
}
} while (!edt);

out_take:
if (likely(edt->prio != PRIO_LIMIT))
clear_cpuidle_map(cpu);
else
set_cpuidle_map(cpu);

take_task(cpu, edt);
return edt;
}

/*
* The currently running task's information is all stored in rq local data
* which is only modified by the local CPU, thereby allowing the data to be
* changed without grabbing the grq lock.
*/
static inline void set_rq_task(struct rq *rq, struct task_struct *p)
{
rq->rq_time_slice = p->time_slice;
rq->rq_last_ran = p->last_ran = rq->clock;
rq->rq_policy = p->policy;
rq->rq_prio = p->prio;
if (p != rq->idle)
rq->rq_running = true;
else
rq->rq_running = false;
}

static void reset_rq_task(struct rq *rq, struct task_struct *p)
{
rq->rq_policy = p->policy;
rq->rq_prio = p->prio;
}

static inline void operate_blk_needs_flush_plug(struct task_struct *p)
{
grq_unlock_irq();
preempt_enable_no_resched();
blk_schedule_flush_plug(p);
}

static inline void task_switch(struct rq *rq, struct task_struct *prev, struct task_struct *next)
{
/*
* Don't stick tasks when a real time task is going to run as
* they may literally get stuck.
*/
if (rt_task(next))
unstick_task(rq, prev);
set_rq_task(rq, next);
grq.nr_switches++;
prev->on_cpu = false;
next->on_cpu = true;
rq->curr = next;

/*
* 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 it can be moved to another cpu/rq.
*/
context_switch(rq, prev, next); /* unlocks the grq */
}

static inline void __do_schedule(struct rq *rq, int cpu)
{
struct task_struct *prev, *next, *idle;
bool deactivate;

prev = rq->curr;

deactivate = false;

if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
if (unlikely(signal_pending_state(prev->state, prev))) {
prev->state = TASK_RUNNING;
} else {
deactivate = true;
/*
* If a worker is going to sleep, notify and
* ask workqueue whether it wants to wake up a
* task to maintain concurrency. If so, wake
* up the task.
*/
if (prev->flags & PF_WQ_WORKER) {
struct task_struct *to_wakeup;

to_wakeup = wq_worker_sleeping(prev, cpu);
if (to_wakeup) {
/* This shouldn't happen, but does */
if (unlikely(to_wakeup == prev)) {
deactivate = false;
} else {
try_to_wake_up_local(to_wakeup);
}
}
}
/*
* 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(prev)) {
operate_blk_needs_flush_plug(prev);
return;
}
}
}

update_clocks(rq);
update_cpu_clock(rq, prev, false);

clear_tsk_need_resched(prev);

idle = rq->idle;
if (idle != prev) {
/* Task changed affinity off this CPU */
if (needs_other_cpu(prev, cpu))
resched_suitable_idle(prev);
else if (!deactivate) {
if (!queued_notrunning()) {
set_rq_task(rq, prev);
goto rerun_prev_unlocked;
} else
swap_sticky(rq, cpu, prev);
}

put_prev_task(rq, prev, deactivate);
}

next = get_runnable_task(rq, cpu, idle);

if (likely(prev != next)) {
task_switch(rq, prev, next);
idle = rq->idle;
}
rerun_prev_unlocked:
return;
}

asmlinkage void __sched schedule(void)
{
int cpu = smp_processor_id();
struct rq *rq = cpu_rq(cpu);

/*
* Enter critical area. No scheduling happen, runqueue is locked.
*/
preempt_disable();
grq_lock_irq();
while(need_resched()) {
grq_lock_irq();
rcu_note_context_switch(cpu);
__do_schedule(rq, cpu);
}
/*
* Leave critical area. Scheduling can be triggered, runqueue is unlocked.
*/
grq_unlock_irq();
preempt_enable_no_resched();
}
EXPORT_SYMBOL(schedule);

#ifdef CONFIG_MUTEX_SPIN_ON_OWNER

static inline bool owner_running(struct mutex *lock, struct task_struct *owner)
{
if (lock->owner != owner)
return false;

/*
* Ensure we emit the owner->on_cpu, dereference _after_ checking
* lock->owner still matches owner, if that fails, owner might
* point to free()d memory, if it still matches, the rcu_read_lock()
* ensures the memory stays valid.
*/
barrier();

return owner->on_cpu;
}

/*
* Look out! "owner" is an entirely speculative pointer
* access and not reliable.
*/
int mutex_spin_on_owner(struct mutex *lock, struct task_struct *owner)
{
rcu_read_lock();
while (owner_running(lock, owner)) {
if (need_resched())
break;

arch_mutex_cpu_relax();
}
rcu_read_unlock();

/*
* We break out the loop above on need_resched() and when the
* owner changed, which is a sign for heavy contention. Return
* success only when lock->owner is NULL.
*/
return lock->owner == NULL;
}
#endif

#ifdef CONFIG_PREEMPT
/*
* this is the entry point to schedule() from in-kernel preemption
* off of preempt_enable. Kernel preemptions off return from interrupt
* occur there and call schedule directly.
*/
asmlinkage void __sched notrace preempt_schedule(void)
{
struct thread_info *ti = current_thread_info();

/*
* 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(ti->preempt_count || irqs_disabled()))
return;

do {
add_preempt_count_notrace(PREEMPT_ACTIVE);
schedule();
sub_preempt_count_notrace(PREEMPT_ACTIVE);

/*
* Check again in case we missed a preemption opportunity
* between schedule and now.
*/
barrier();
} while (need_resched());
}
EXPORT_SYMBOL(preempt_schedule);

/*
* 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 void __sched preempt_schedule_irq(void)
{
struct thread_info *ti = current_thread_info();

/* Catch callers which need to be fixed */
BUG_ON(ti->preempt_count || !irqs_disabled());

do {
add_preempt_count(PREEMPT_ACTIVE);
local_irq_enable();
schedule();
local_irq_disable();
sub_preempt_count(PREEMPT_ACTIVE);

/*
* Check again in case we missed a preemption opportunity
* between schedule and now.
*/
barrier();
} while (need_resched());
}

#endif /* CONFIG_PREEMPT */

int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags,
void *key)
{
return try_to_wake_up(curr->private, mode, wake_flags);
}
EXPORT_SYMBOL(default_wake_function);

/*
* The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
* wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
* number) then we wake all the non-exclusive tasks and one exclusive task.
*
* There are circumstances in which we can try to wake a task which has already
* started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
* zero in this (rare) case, and we handle it by continuing to scan the queue.
*/
static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, int wake_flags, void *key)
{
struct list_head *tmp, *next;

list_for_each_safe(tmp, next, &q->task_list) {
wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list);
unsigned int flags = curr->flags;

if (curr->func(curr, mode, wake_flags, key) &&
(flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
break;
}
}

/**
* __wake_up - wake up threads blocked on a waitqueue.
* @q: the waitqueue
* @mode: which threads
* @nr_exclusive: how many wake-one or wake-many threads to wake up
* @key: is directly passed to the wakeup function
*
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
void __wake_up(wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, void *key)
{
unsigned long flags;

spin_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr_exclusive, 0, key);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL(__wake_up);

/*
* Same as __wake_up but called with the spinlock in wait_queue_head_t held.
*/
void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
{
__wake_up_common(q, mode, 1, 0, NULL);
}
EXPORT_SYMBOL_GPL(__wake_up_locked);

void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
{
__wake_up_common(q, mode, 1, 0, key);
}
EXPORT_SYMBOL_GPL(__wake_up_locked_key);

/**
* __wake_up_sync_key - wake up threads blocked on a waitqueue.
* @q: the waitqueue
* @mode: which threads
* @nr_exclusive: how many wake-one or wake-many threads to wake up
* @key: opaque value to be passed to wakeup targets
*
* The sync wakeup differs that the waker knows that it will schedule
* away soon, so while the target thread will be woken up, it will not
* be migrated to another CPU - ie. the two threads are 'synchronised'
* with each other. This can prevent needless bouncing between CPUs.
*
* On UP it can prevent extra preemption.
*
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
int nr_exclusive, void *key)
{
unsigned long flags;
int wake_flags = WF_SYNC;

if (unlikely(!q))
return;

if (unlikely(!nr_exclusive))
wake_flags = 0;

spin_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr_exclusive, wake_flags, key);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL_GPL(__wake_up_sync_key);

/**
* __wake_up_sync - wake up threads blocked on a waitqueue.
* @q: the waitqueue
* @mode: which threads
* @nr_exclusive: how many wake-one or wake-many threads to wake up
*
* The sync wakeup differs that the waker knows that it will schedule
* away soon, so while the target thread will be woken up, it will not
* be migrated to another CPU - ie. the two threads are 'synchronised'
* with each other. This can prevent needless bouncing between CPUs.
*
* On UP it can prevent extra preemption.
*/
void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
{
unsigned long flags;
int sync = 1;

if (unlikely(!q))
return;

if (unlikely(!nr_exclusive))
sync = 0;

spin_lock_irqsave(&q->lock, flags);
__wake_up_common(q, mode, nr_exclusive, sync, NULL);
spin_unlock_irqrestore(&q->lock, flags);
}
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */

/**
* complete: - signals a single thread waiting on this completion
* @x: holds the state of this particular completion
*
* This will wake up a single thread waiting on this completion. Threads will be
* awakened in the same order in which they were queued.
*
* See also complete_all(), wait_for_completion() and related routines.
*
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
void complete(struct completion *x)
{
unsigned long flags;

spin_lock_irqsave(&x->wait.lock, flags);
x->done++;
__wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
spin_unlock_irqrestore(&x->wait.lock, flags);
}
EXPORT_SYMBOL(complete);

/**
* complete_all: - signals all threads waiting on this completion
* @x: holds the state of this particular completion
*
* This will wake up all threads waiting on this particular completion event.
*
* It may be assumed that this function implies a write memory barrier before
* changing the task state if and only if any tasks are woken up.
*/
void complete_all(struct completion *x)
{
unsigned long flags;

spin_lock_irqsave(&x->wait.lock, flags);
x->done += UINT_MAX/2;
__wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
spin_unlock_irqrestore(&x->wait.lock, flags);
}
EXPORT_SYMBOL(complete_all);

static inline long __sched
do_wait_for_common(struct completion *x, long timeout, int state)
{
if (!x->done) {
DECLARE_WAITQUEUE(wait, current);

__add_wait_queue_tail_exclusive(&x->wait, &wait);
do {
if (signal_pending_state(state, current)) {
timeout = -ERESTARTSYS;
break;
}
__set_current_state(state);
spin_unlock_irq(&x->wait.lock);
timeout = schedule_timeout(timeout);
spin_lock_irq(&x->wait.lock);
} while (!x->done && timeout);
__remove_wait_queue(&x->wait, &wait);
if (!x->done)
return timeout;
}
x->done--;
return timeout ?: 1;
}

static long __sched
wait_for_common(struct completion *x, long timeout, int state)
{
might_sleep();

spin_lock_irq(&x->wait.lock);
timeout = do_wait_for_common(x, timeout, state);
spin_unlock_irq(&x->wait.lock);
return timeout;
}

/**
* wait_for_completion: - waits for completion of a task
* @x: holds the state of this particular completion
*
* This waits to be signaled for completion of a specific task. It is NOT
* interruptible and there is no timeout.
*
* See also similar routines (i.e. wait_for_completion_timeout()) with timeout
* and interrupt capability. Also see complete().
*/
void __sched wait_for_completion(struct completion *x)
{
wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_for_completion);

/**
* wait_for_completion_timeout: - waits for completion of a task (w/timeout)
* @x: holds the state of this particular completion
* @timeout: timeout value in jiffies
*
* This waits for either a completion of a specific task to be signaled or for a
* specified timeout to expire. The timeout is in jiffies. It is not
* interruptible.
*
* The return value is 0 if timed out, and positive (at least 1, or number of
* jiffies left till timeout) if completed.
*/
unsigned long __sched
wait_for_completion_timeout(struct completion *x, unsigned long timeout)
{
return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_for_completion_timeout);

/**
* wait_for_completion_interruptible: - waits for completion of a task (w/intr)
* @x: holds the state of this particular completion
*
* This waits for completion of a specific task to be signaled. It is
* interruptible.
*
* The return value is -ERESTARTSYS if interrupted, 0 if completed.
*/
int __sched wait_for_completion_interruptible(struct completion *x)
{
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
if (t == -ERESTARTSYS)
return t;
return 0;
}
EXPORT_SYMBOL(wait_for_completion_interruptible);

/**
* wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr))
* @x: holds the state of this particular completion
* @timeout: timeout value in jiffies
*
* This waits for either a completion of a specific task to be signaled or for a
* specified timeout to expire. It is interruptible. The timeout is in jiffies.
*
* The return value is -ERESTARTSYS if interrupted, 0 if timed out,
* positive (at least 1, or number of jiffies left till timeout) if completed.
*/
long __sched
wait_for_completion_interruptible_timeout(struct completion *x,
unsigned long timeout)
{
return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
}
EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);

/**
* wait_for_completion_killable: - waits for completion of a task (killable)
* @x: holds the state of this particular completion
*
* This waits to be signaled for completion of a specific task. It can be
* interrupted by a kill signal.
*
* The return value is -ERESTARTSYS if interrupted, 0 if timed out,
* positive (at least 1, or number of jiffies left till timeout) if completed.
*/
int __sched wait_for_completion_killable(struct completion *x)
{
long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
if (t == -ERESTARTSYS)
return t;
return 0;
}
EXPORT_SYMBOL(wait_for_completion_killable);

/**
* wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable))
* @x: holds the state of this particular completion
* @timeout: timeout value in jiffies
*
* This waits for either a completion of a specific task to be
* signaled or for a specified timeout to expire. It can be
* interrupted by a kill signal. The timeout is in jiffies.
*/
long __sched
wait_for_completion_killable_timeout(struct completion *x,
unsigned long timeout)
{
return wait_for_common(x, timeout, TASK_KILLABLE);
}
EXPORT_SYMBOL(wait_for_completion_killable_timeout);

/**
* try_wait_for_completion - try to decrement a completion without blocking
* @x: completion structure
*
* Returns: 0 if a decrement cannot be done without blocking
* 1 if a decrement succeeded.
*
* If a completion is being used as a counting completion,
* attempt to decrement the counter without blocking. This
* enables us to avoid waiting if the resource the completion
* is protecting is not available.
*/
bool try_wait_for_completion(struct completion *x)
{
unsigned long flags;
int ret = 1;

spin_lock_irqsave(&x->wait.lock, flags);
if (!x->done)
ret = 0;
else
x->done--;
spin_unlock_irqrestore(&x->wait.lock, flags);
return ret;
}
EXPORT_SYMBOL(try_wait_for_completion);

/**
* completion_done - Test to see if a completion has any waiters
* @x: completion structure
*
* Returns: 0 if there are waiters (wait_for_completion() in progress)
* 1 if there are no waiters.
*
*/
bool completion_done(struct completion *x)
{
unsigned long flags;
int ret = 1;

spin_lock_irqsave(&x->wait.lock, flags);
if (!x->done)
ret = 0;
spin_unlock_irqrestore(&x->wait.lock, flags);
return ret;
}
EXPORT_SYMBOL(completion_done);

static long __sched
sleep_on_common(wait_queue_head_t *q, int state, long timeout)
{
unsigned long flags;
wait_queue_t wait;

init_waitqueue_entry(&wait, current);

__set_current_state(state);

spin_lock_irqsave(&q->lock, flags);
__add_wait_queue(q, &wait);
spin_unlock(&q->lock);
timeout = schedule_timeout(timeout);
spin_lock_irq(&q->lock);
__remove_wait_queue(q, &wait);
spin_unlock_irqrestore(&q->lock, flags);

return timeout;
}

void __sched interruptible_sleep_on(wait_queue_head_t *q)
{
sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
EXPORT_SYMBOL(interruptible_sleep_on);

long __sched
interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
}
EXPORT_SYMBOL(interruptible_sleep_on_timeout);

void __sched sleep_on(wait_queue_head_t *q)
{
sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
}
EXPORT_SYMBOL(sleep_on);

long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
}
EXPORT_SYMBOL(sleep_on_timeout);

#ifdef CONFIG_RT_MUTEXES

/*
* rt_mutex_setprio - set the current priority of a task
* @p: task
* @prio: prio value (kernel-internal form)
*
* 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.
*/
void rt_mutex_setprio(struct task_struct *p, int prio)
{
unsigned long flags;
int queued, oldprio;
struct rq *rq;

BUG_ON(prio < 0 || prio > MAX_PRIO);

rq = task_grq_lock(p, &flags);

trace_sched_pi_setprio(p, prio);
oldprio = p->prio;
queued = task_queued(p);
if (queued)
dequeue_task(p);
p->prio = prio;
if (task_running(p) && prio > oldprio)
resched_task(p);
if (queued) {
enqueue_task(p);
try_preempt(p, rq);
}

task_grq_unlock(&flags);
}

#endif

void set_user_nice(struct task_struct *p, long nice)
{
int queued, new_static, old_static;
unsigned long flags;
struct rq *rq;

if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
return;
new_static = NICE_TO_PRIO(nice);
/*
* We have to be careful, if called from sys_setpriority(),
* the task might be in the middle of scheduling on another CPU.
*/
rq = time_task_grq_lock(p, &flags);
/*
* 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 (has_rt_policy(p)) {
p->static_prio = new_static;
goto out_unlock;
}
queued = task_queued(p);
if (queued)
dequeue_task(p);

old_static = p->static_prio;
p->static_prio = new_static;
p->prio = new_static;

if (queued) {
enqueue_task(p);
if (new_static < old_static)
try_preempt(p, rq);
} else if (task_running(p)) {
reset_rq_task(rq, p);
if (old_static < new_static)
resched_task(p);
}
out_unlock:
task_grq_unlock(&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 = 20 - 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.
*/
if (increment < -40)
increment = -40;
if (increment > 40)
increment = 40;

nice = TASK_NICE(current) + increment;
if (nice < -20)
nice = -20;
if (nice > 19)
nice = 19;

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

/**
* task_prio - return the priority value of a given task.
* @p: the task in question.
*
* This is the priority value as seen by users in /proc.
* RT tasks are offset by -100. Normal tasks are centered around 1.
*/
int task_prio(const struct task_struct *p)
{
return p->static_prio;
}

/**
* task_nice - return the nice value of a given task.
* @p: the task in question.
*/
int task_nice(const struct task_struct *p)
{
return TASK_NICE(p);
}
EXPORT_SYMBOL_GPL(task_nice);

/**
* idle_cpu - is a given cpu idle currently?
* @cpu: the processor in question.
*/
int idle_cpu(int cpu)
{
return cpu_curr(cpu) == cpu_rq(cpu)->idle;
}

/**
* idle_task - return the idle task for a given cpu.
* @cpu: the processor in question.
*/
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.
*/
static inline struct task_struct *find_process_by_pid(pid_t pid)
{
return pid ? find_task_by_vpid(pid) : current;
}

/* Actually do priority change: must hold grq lock. */
static void
__setscheduler(struct task_struct *p, struct rq *rq, int policy, int prio)
{
int oldrtprio, oldprio;

p->policy = policy;
oldrtprio = p->rt_priority;
p->rt_priority = prio;
p->normal_prio = normal_prio(p);
oldprio = p->prio;
/* we are holding p->pi_lock already */
p->prio = rt_mutex_getprio(p);
if (task_running(p)) {
reset_rq_task(rq, p);
/* Resched only if we might now be preempted */
if (p->prio > oldprio || p->rt_priority > oldrtprio)
resched_task(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);
if (cred->user->user_ns == pcred->user->user_ns)
match = (cred->euid == pcred->euid ||
cred->euid == pcred->uid);
else
match = false;
rcu_read_unlock();
return match;
}

static int __sched_setscheduler(struct task_struct *p, int policy,
const struct sched_param *param, bool user)
{
struct sched_param zero_param = { .sched_priority = 0 };
int queued, retval, oldpolicy = -1;
unsigned long flags, rlim_rtprio = 0;
int reset_on_fork;
struct rq *rq;

/* may grab non-irq protected spin_locks */
BUG_ON(in_interrupt());

if (is_rt_policy(policy) && !capable(CAP_SYS_NICE)) {
unsigned long lflags;

if (!lock_task_sighand(p, &lflags))
return -ESRCH;
rlim_rtprio = task_rlimit(p, RLIMIT_RTPRIO);
unlock_task_sighand(p, &lflags);
if (rlim_rtprio)
goto recheck;
param = &zero_param;
}
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 = !!(policy & SCHED_RESET_ON_FORK);
policy &= ~SCHED_RESET_ON_FORK;

if (!SCHED_RANGE(policy))
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 is 0.
*/
if (param->sched_priority < 0 ||
(p->mm && param->sched_priority > MAX_USER_RT_PRIO - 1) ||
(!p->mm && param->sched_priority > MAX_RT_PRIO - 1))
return -EINVAL;
if (is_rt_policy(policy) != (param->sched_priority != 0))
return -EINVAL;

/*
* Allow unprivileged RT tasks to decrease priority:
*/
if (user && !capable(CAP_SYS_NICE)) {
if (is_rt_policy(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 (param->sched_priority > p->rt_priority &&
param->sched_priority > rlim_rtprio)
return -EPERM;
} else {
switch (p->policy) {
case SCHED_BATCH:
if (policy == SCHED_BATCH)
goto out;
if (policy != SCHED_IDLEPRIO)
return -EPERM;
break;
case SCHED_IDLEPRIO:
if (policy == SCHED_IDLEPRIO)
goto out;
return -EPERM;
default:
break;
}
}

/* 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;
}

/*
* 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, the grunqueue lock must be
* held.
*/
rq = __task_grq_lock(p);

/*
* Changing the policy of the stop threads its a very bad idea
*/
if (p == rq->stop) {
__task_grq_unlock();
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
return -EINVAL;
}

/*
* If not changing anything there's no need to proceed further:
*/
if (unlikely(policy == p->policy && (!is_rt_policy(policy) ||
param->sched_priority == p->rt_priority))) {

__task_grq_unlock();
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
return 0;
}

/* recheck policy now with rq lock held */
if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
policy = oldpolicy = -1;
__task_grq_unlock();
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
goto recheck;
}
update_clocks(rq);
p->sched_reset_on_fork = reset_on_fork;

queued = task_queued(p);
if (queued)
dequeue_task(p);
__setscheduler(p, rq, policy, param->sched_priority);
if (queued) {
enqueue_task(p);
try_preempt(p, rq);
}
__task_grq_unlock();
raw_spin_unlock_irqrestore(&p->pi_lock, flags);

rt_mutex_adjust_pi(p);
out:
return 0;
}

/**
* 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.
*
* 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);
}

EXPORT_SYMBOL_GPL(sched_setscheduler);

/**
* 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.
*/
int sched_setscheduler_nocheck(struct task_struct *p, int policy,
const struct sched_param *param)
{
return __sched_setscheduler(p, policy, param, false);
}

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 (p != NULL)
retval = sched_setscheduler(p, policy, &lparam);
rcu_read_unlock();

return retval;
}

/**
* sys_sched_setscheduler - set/change the scheduler policy and RT priority
* @pid: the pid in question.
* @policy: new policy.
* @param: structure containing the new RT priority.
*/
asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
struct sched_param __user *param)
{
/* negative values for policy are not valid */
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.
*/
SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param)
{
return do_sched_setscheduler(pid, -1, param);
}

/**
* sys_sched_getscheduler - get the policy (scheduling class) of a thread
* @pid: the pid in question.
*/
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.
*/
SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param)
{
struct sched_param lp;
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;

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;
}

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 (!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) && !ns_capable(task_user_ns(p), CAP_SYS_NICE))
goto out_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);

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,
cpumask_t *new_mask)
{
if (len < sizeof(cpumask_t)) {
memset(new_mask, 0, sizeof(cpumask_t));
} else if (len > sizeof(cpumask_t)) {
len = sizeof(cpumask_t);
}
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
*/
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;
unsigned long flags;
int retval;

get_online_cpus();
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;

grq_lock_irqsave(&flags);
cpumask_and(mask, tsk_cpus_allowed(p), cpu_online_mask);
grq_unlock_irqrestore(&flags);

out_unlock:
rcu_read_unlock();
put_online_cpus();

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
*/
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) {
size_t 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.
*/
SYSCALL_DEFINE0(sched_yield)
{
struct task_struct *p;

p = current;
grq_lock_irq();
schedstat_inc(task_rq(p), yld_count);
requeue_task(p);

/*
* Since we are going to call schedule() anyway, there's
* no need to preempt or enable interrupts:
*/
__release(grq.lock);
spin_release(&grq.lock.dep_map, 1, _THIS_IP_);
do_raw_spin_unlock(&grq.lock);
preempt_enable_no_resched();

schedule();

return 0;
}

static inline bool should_resched(void)
{
return need_resched() && !(preempt_count() & PREEMPT_ACTIVE);
}

static void __cond_resched(void)
{
if (unlikely(system_state != SYSTEM_RUNNING))
return;

add_preempt_count(PREEMPT_ACTIVE);
schedule();
sub_preempt_count(PREEMPT_ACTIVE);
}

int __sched _cond_resched(void)
{
if (should_resched()) {
__cond_resched();
return 1;
}
return 0;
}
EXPORT_SYMBOL(_cond_resched);

/*
* __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_PREEMPT. 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();
int ret = 0;

lockdep_assert_held(lock);

if (spin_needbreak(lock) || resched) {
spin_unlock(lock);
if (resched)
__cond_resched();
else
cpu_relax();
ret = 1;
spin_lock(lock);
}
return ret;
}
EXPORT_SYMBOL(__cond_resched_lock);

int __sched __cond_resched_softirq(void)
{
BUG_ON(!in_softirq());

if (should_resched()) {
local_bh_enable();
__cond_resched();
local_bh_disable();
return 1;
}
return 0;
}
EXPORT_SYMBOL(__cond_resched_softirq);

/**
* yield - yield the current processor to other threads.
*
* This is a shortcut for kernel-space yielding - it marks the
* thread runnable and calls sys_sched_yield().
*/
void __sched yield(void)
{
set_current_state(TASK_RUNNING);
sys_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.
*
* Returns true if we indeed boosted the target task.
*/
bool __sched yield_to(struct task_struct *p, bool preempt)
{
unsigned long flags;
bool yielded = 0;
struct rq *rq;

rq = this_rq();
grq_lock_irqsave(&flags);
if (task_running(p) || p->state)
goto out_unlock;
yielded = 1;
p->time_slice += rq->rq_time_slice;
rq->rq_time_slice = 0;
if (p->time_slice > timeslice())
p->time_slice = timeslice();
set_tsk_need_resched(rq->curr);
out_unlock:
grq_unlock_irqrestore(&flags);

if (yielded)
schedule();
return yielded;
}
EXPORT_SYMBOL_GPL(yield_to);

/*
* 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)
*/
void __sched io_schedule(void)
{
struct rq *rq = raw_rq();

delayacct_blkio_start();
atomic_inc(&rq->nr_iowait);
blk_flush_plug(current);
current->in_iowait = 1;
schedule();
current->in_iowait = 0;
atomic_dec(&rq->nr_iowait);
delayacct_blkio_end();
}
EXPORT_SYMBOL(io_schedule);

long __sched io_schedule_timeout(long timeout)
{
struct rq *rq = raw_rq();
long ret;

delayacct_blkio_start();
atomic_inc(&rq->nr_iowait);
blk_flush_plug(current);
current->in_iowait = 1;
ret = schedule_timeout(timeout);
current->in_iowait = 0;
atomic_dec(&rq->nr_iowait);
delayacct_blkio_end();
return ret;
}

/**
* sys_sched_get_priority_max - return maximum RT priority.
* @policy: scheduling class.
*
* this syscall returns the maximum rt_priority that can be used
* by a given scheduling class.
*/
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_IDLEPRIO:
ret = 0;
break;
}
return ret;
}

/**
* sys_sched_get_priority_min - return minimum RT priority.
* @policy: scheduling class.
*
* this syscall returns the minimum rt_priority that can be used
* by a given scheduling class.
*/
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_IDLEPRIO:
ret = 0;
break;
}
return ret;
}

/**
* sys_sched_rr_get_interval - return the default timeslice of a process.
* @pid: pid of the process.
* @interval: userspace pointer to the timeslice value.
*
* this syscall writes the default timeslice value of a given process
* into the user-space timespec buffer. A value of '0' means infinity.
*/
SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid,
struct timespec __user *, interval)
{
struct task_struct *p;
unsigned int time_slice;
unsigned long flags;
int retval;
struct timespec t;

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;

grq_lock_irqsave(&flags);
time_slice = p->policy == SCHED_FIFO ? 0 : MS_TO_NS(rr_interval);
grq_unlock_irqrestore(&flags);

rcu_read_unlock();
t = ns_to_timespec(time_slice);
retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
return retval;

out_unlock:
rcu_read_unlock();
return retval;
}

static const char stat_nam[] = TASK_STATE_TO_CHAR_STR;

void sched_show_task(struct task_struct *p)
{
unsigned long free = 0;
unsigned state;

state = p->state ? __ffs(p->state) + 1 : 0;
printk(KERN_INFO "%-15.15s %c", p->comm,
state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
#if BITS_PER_LONG == 32
if (state == TASK_RUNNING)
printk(KERN_CONT " running ");
else
printk(KERN_CONT " %08lx ", thread_saved_pc(p));
#else
if (state == TASK_RUNNING)
printk(KERN_CONT " running task ");
else
printk(KERN_CONT " %016lx ", thread_saved_pc(p));
#endif
#ifdef CONFIG_DEBUG_STACK_USAGE
free = stack_not_used(p);
#endif
printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free,
task_pid_nr(p), task_pid_nr(p->real_parent),
(unsigned long)task_thread_info(p)->flags);

show_stack(p, NULL);
}

void show_state_filter(unsigned long state_filter)
{
struct task_struct *g, *p;

#if BITS_PER_LONG == 32
printk(KERN_INFO
" task PC stack pid father\n");
#else
printk(KERN_INFO
" task PC stack pid father\n");
#endif
rcu_read_lock();
do_each_thread(g, p) {
/*
* reset the NMI-timeout, listing all files on a slow
* console might take a lot of time:
*/
touch_nmi_watchdog();
if (!state_filter || (p->state & state_filter))
sched_show_task(p);
} while_each_thread(g, p);

touch_all_softlockup_watchdogs();

rcu_read_unlock();
/*
* Only show locks if all tasks are dumped:
*/
if (!state_filter)
debug_show_all_locks();
}

#ifdef CONFIG_SMP
void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask)
{
cpumask_copy(tsk_cpus_allowed(p), new_mask);
}
#endif

/**
* 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;

time_grq_lock(rq, &flags);
idle->last_ran = rq->clock;
idle->state = TASK_RUNNING;
/* Setting prio to illegal value shouldn't matter when never queued */
idle->prio = PRIO_LIMIT;
set_rq_task(rq, idle);
do_set_cpus_allowed(idle, &cpumask_of_cpu(cpu));
/* Silence PROVE_RCU */
rcu_read_lock();
set_task_cpu(idle, cpu);
rcu_read_unlock();
rq->curr = rq->idle = idle;
idle->on_cpu = 1;
grq_unlock_irqrestore(&flags);

/* Set the preempt count _outside_ the spinlocks! */
task_thread_info(idle)->preempt_count = 0;

ftrace_graph_init_idle_task(idle, cpu);
#if defined(CONFIG_SMP)
sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu);
#endif
}

#ifdef CONFIG_SMP
#ifdef CONFIG_NO_HZ
void select_nohz_load_balancer(int stop_tick)
{
}

void set_cpu_sd_state_idle(void) {}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
/**
* lowest_flag_domain - Return lowest sched_domain containing flag.
* @cpu: The cpu whose lowest level of sched domain is to
* be returned.
* @flag: The flag to check for the lowest sched_domain
* for the given cpu.
*
* Returns the lowest sched_domain of a cpu which contains the given flag.
*/
static inline struct sched_domain *lowest_flag_domain(int cpu, int flag)
{
struct sched_domain *sd;

for_each_domain(cpu, sd)
if (sd && (sd->flags & flag))
break;

return sd;
}

/**
* for_each_flag_domain - Iterates over sched_domains containing the flag.
* @cpu: The cpu whose domains we're iterating over.
* @sd: variable holding the value of the power_savings_sd
* for cpu.
* @flag: The flag to filter the sched_domains to be iterated.
*
* Iterates over all the scheduler domains for a given cpu that has the 'flag'
* set, starting from the lowest sched_domain to the highest.
*/
#define for_each_flag_domain(cpu, sd, flag) \
for (sd = lowest_flag_domain(cpu, flag); \
(sd && (sd->flags & flag)); sd = sd->parent)

#endif /* (CONFIG_SCHED_MC || CONFIG_SCHED_SMT) */

static inline void resched_cpu(int cpu)
{
unsigned long flags;

grq_lock_irqsave(&flags);
resched_task(cpu_curr(cpu));
grq_unlock_irqrestore(&flags);
}

/*
* 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 cpu = smp_processor_id();
int i;
struct sched_domain *sd;

rcu_read_lock();
for_each_domain(cpu, sd) {
for_each_cpu(i, sched_domain_span(sd)) {
if (!idle_cpu(i))
cpu = i;
goto unlock;
}
}
unlock:
rcu_read_unlock();
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.
*/
void wake_up_idle_cpu(int cpu)
{
struct task_struct *idle;
struct rq *rq;

if (cpu == smp_processor_id())
return;

rq = cpu_rq(cpu);
idle = rq->idle;

/*
* This is safe, as this function is called with the timer
* wheel base lock of (cpu) held. When the CPU is on the way
* to idle and has not yet set rq->curr to idle then it will
* be serialised on the timer wheel base lock and take the new
* timer into account automatically.
*/
if (unlikely(rq->curr != idle))
return;

/*
* We can set TIF_RESCHED on the idle task of the other CPU
* lockless. The worst case is that the other CPU runs the
* idle task through an additional NOOP schedule()
*/
set_tsk_need_resched(idle);

/* NEED_RESCHED must be visible before we test polling */
smp_mb();
if (!tsk_is_polling(idle))
smp_send_reschedule(cpu);
}

#endif /* CONFIG_NO_HZ */

/*
* 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.
*/
int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask)
{
bool running_wrong = false;
bool queued = false;
unsigned long flags;
struct rq *rq;
int ret = 0;

rq = task_grq_lock(p, &flags);

if (cpumask_equal(tsk_cpus_allowed(p), new_mask))
goto out;

if (!cpumask_intersects(new_mask, cpu_active_mask)) {
ret = -EINVAL;
goto out;
}

if (unlikely((p->flags & PF_THREAD_BOUND) && p != current)) {
ret = -EINVAL;
goto out;
}

queued = task_queued(p);

do_set_cpus_allowed(p, new_mask);

/* 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)) {
/* Task is running on the wrong cpu now, reschedule it. */
if (rq == this_rq()) {
set_tsk_need_resched(p);
running_wrong = true;
} else
resched_task(p);
} else
set_task_cpu(p, cpumask_any_and(cpu_active_mask, new_mask));

out:
if (queued)
try_preempt(p, rq);
task_grq_unlock(&flags);

if (running_wrong)
_cond_resched();

return ret;
}
EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);

#ifdef CONFIG_HOTPLUG_CPU
/* Run through task list and find tasks affined to just the dead cpu, then
* allocate a new affinity */
static void break_sole_affinity(int src_cpu, struct task_struct *idle)
{
struct task_struct *p, *t;

do_each_thread(t, p) {
if (p != idle && !online_cpus(p)) {
cpumask_copy(tsk_cpus_allowed(p), cpu_possible_mask);
/*
* 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(KERN_INFO "process %d (%s) no "
"longer affine to cpu %d\n",
task_pid_nr(p), p->comm, src_cpu);
}
}
clear_sticky(p);
} while_each_thread(t, p);
}

/*
* Schedules idle task to be the next runnable task on current CPU.
* It does so by boosting its priority to highest possible.
* Used by CPU offline code.
*/
void sched_idle_next(struct rq *rq, int this_cpu, struct task_struct *idle)
{
/* cpu has to be offline */
BUG_ON(cpu_online(this_cpu));

__setscheduler(idle, rq, SCHED_FIFO, STOP_PRIO);

activate_idle_task(idle);
set_tsk_need_resched(rq->curr);
}

/*
* 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(cpu_online(smp_processor_id()));

if (mm != &init_mm)
switch_mm(mm, &init_mm, current);
mmdrop(mm);
}
#endif /* CONFIG_HOTPLUG_CPU */
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 = MAX_USER_RT_PRIO - 1 };
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 rt scheduling prio so that
* it can die in pieces.
*/
sched_setscheduler_nocheck(old_stop, SCHED_FIFO, &start_param);
}
}


#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)

static struct ctl_table sd_ctl_dir[] = {
{
.procname = "sched_domain",
.mode = 0555,
},
{}
};

static struct ctl_table sd_ctl_root[] = {
{
.procname = "kernel",
.mode = 0555,
.child = sd_ctl_dir,
},
{}
};

static struct ctl_table *sd_alloc_ctl_entry(int n)
{
struct ctl_table *entry =
kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);

return entry;
}

static void sd_free_ctl_entry(struct ctl_table **tablep)
{
struct ctl_table *entry;

/*
* In the intermediate directories, both the child directory and
* procname are dynamically allocated and could fail but the mode
* will always be set. In the lowest directory the names are
* static strings and all have proc handlers.
*/
for (entry = *tablep; entry->mode; entry++) {
if (entry->child)
sd_free_ctl_entry(&entry->child);
if (entry->proc_handler == NULL)
kfree(entry->procname);
}

kfree(*tablep);
*tablep = NULL;
}

static void
set_table_entry(struct ctl_table *entry,
const char *procname, void *data, int maxlen,
mode_t mode, proc_handler *proc_handler)
{
entry->procname = procname;
entry->data = data;
entry->maxlen = maxlen;
entry->mode = mode;
entry->proc_handler = proc_handler;
}

static struct ctl_table *
sd_alloc_ctl_domain_table(struct sched_domain *sd)
{
struct ctl_table *table = sd_alloc_ctl_entry(13);

if (table == NULL)
return NULL;

set_table_entry(&table[0], "min_interval", &sd->min_interval,
sizeof(long), 0644, proc_doulongvec_minmax);
set_table_entry(&table[1], "max_interval", &sd->max_interval,
sizeof(long), 0644, proc_doulongvec_minmax);
set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[9], "cache_nice_tries",
&sd->cache_nice_tries,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[10], "flags", &sd->flags,
sizeof(int), 0644, proc_dointvec_minmax);
set_table_entry(&table[11], "name", sd->name,
CORENAME_MAX_SIZE, 0444, proc_dostring);
/* &table[12] is terminator */

return table;
}

static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
{
struct ctl_table *entry, *table;
struct sched_domain *sd;
int domain_num = 0, i;
char buf[32];

for_each_domain(cpu, sd)
domain_num++;
entry = table = sd_alloc_ctl_entry(domain_num + 1);
if (table == NULL)
return NULL;

i = 0;
for_each_domain(cpu, sd) {
snprintf(buf, 32, "domain%d", i);
entry->procname = kstrdup(buf, GFP_KERNEL);
entry->mode = 0555;
entry->child = sd_alloc_ctl_domain_table(sd);
entry++;
i++;
}
return table;
}

static struct ctl_table_header *sd_sysctl_header;
static void register_sched_domain_sysctl(void)
{
int i, cpu_num = num_possible_cpus();
struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
char buf[32];

WARN_ON(sd_ctl_dir[0].child);
sd_ctl_dir[0].child = entry;

if (entry == NULL)
return;

for_each_possible_cpu(i) {
snprintf(buf, 32, "cpu%d", i);
entry->procname = kstrdup(buf, GFP_KERNEL);
entry->mode = 0555;
entry->child = sd_alloc_ctl_cpu_table(i);
entry++;
}

WARN_ON(sd_sysctl_header);
sd_sysctl_header = register_sysctl_table(sd_ctl_root);
}

/* may be called multiple times per register */
static void unregister_sched_domain_sysctl(void)
{
if (sd_sysctl_header)
unregister_sysctl_table(sd_sysctl_header);
sd_sysctl_header = NULL;
if (sd_ctl_dir[0].child)
sd_free_ctl_entry(&sd_ctl_dir[0].child);
}
#else
static void register_sched_domain_sysctl(void)
{
}
static void unregister_sched_domain_sysctl(void)
{
}
#endif

static void set_rq_online(struct rq *rq)
{
if (!rq->online) {
cpumask_set_cpu(cpu_of(rq), rq->rd->online);
rq->online = true;
}
}

static void set_rq_offline(struct rq *rq)
{
if (rq->online) {
cpumask_clear_cpu(cpu_of(rq), rq->rd->online);
rq->online = false;
}
}

/*
* migration_call - callback that gets triggered when a CPU is added.
*/
static int __cpuinit
migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
{
int cpu = (long)hcpu;
unsigned long flags;
struct rq *rq = cpu_rq(cpu);
#ifdef CONFIG_HOTPLUG_CPU
struct task_struct *idle = rq->idle;
#endif

switch (action & ~CPU_TASKS_FROZEN) {

case CPU_UP_PREPARE:
break;

case CPU_ONLINE:
/* Update our root-domain */
grq_lock_irqsave(&flags);
if (rq->rd) {
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));

set_rq_online(rq);
}
grq.noc = num_online_cpus();
grq_unlock_irqrestore(&flags);
break;

#ifdef CONFIG_HOTPLUG_CPU
case CPU_DEAD:
/* Idle task back to normal (off runqueue, low prio) */
grq_lock_irq();
put_prev_task(rq, idle, true);
idle->static_prio = MAX_PRIO;
__setscheduler(idle, rq, SCHED_NORMAL, 0);
idle->prio = PRIO_LIMIT;
set_rq_task(rq, idle);
update_clocks(rq);
grq_unlock_irq();
break;

case CPU_DYING:
/* Update our root-domain */
grq_lock_irqsave(&flags);
sched_idle_next(rq, cpu, idle);
if (rq->rd) {
BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span));
set_rq_offline(rq);
}
break_sole_affinity(cpu, idle);
grq.noc = num_online_cpus();
grq_unlock_irqrestore(&flags);
break;
#endif
}
return NOTIFY_OK;
}

/*
* Register at high priority so that task migration (migrate_all_tasks)
* happens before everything else. This has to be lower priority than
* the notifier in the perf_counter subsystem, though.
*/
static struct notifier_block __cpuinitdata migration_notifier = {
.notifier_call = migration_call,
.priority = CPU_PRI_MIGRATION,
};

static int __cpuinit sched_cpu_active(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
case CPU_DOWN_FAILED:
set_cpu_active((long)hcpu, true);
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}

static int __cpuinit sched_cpu_inactive(struct notifier_block *nfb,
unsigned long action, void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_PREPARE:
set_cpu_active((long)hcpu, false);
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}

int __init migration_init(void)
{
void *cpu = (void *)(long)smp_processor_id();
int err;

/* Initialise migration for the boot CPU */
err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
BUG_ON(err == NOTIFY_BAD);
migration_call(&migration_notifier, CPU_ONLINE, cpu);
register_cpu_notifier(&migration_notifier);

/* Register cpu active notifiers */
cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE);
cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE);

return 0;
}
early_initcall(migration_init);
#endif

#ifdef CONFIG_SMP

static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */

#ifdef CONFIG_SCHED_DEBUG

static __read_mostly int sched_domain_debug_enabled;

static int __init sched_domain_debug_setup(char *str)
{
sched_domain_debug_enabled = 1;

return 0;
}
early_param("sched_debug", sched_domain_debug_setup);

static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
struct cpumask *groupmask)
{
struct sched_group *group = sd->groups;
char str[256];

cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd));
cpumask_clear(groupmask);

printk(KERN_DEBUG "%*s domain %d: ", level, "", level);

if (!(sd->flags & SD_LOAD_BALANCE)) {
printk("does not load-balance\n");
if (sd->parent)
printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
" has parent");
return -1;
}

printk(KERN_CONT "span %s level %s\n", str, sd->name);

if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) {
printk(KERN_ERR "ERROR: domain->span does not contain "
"CPU%d\n", cpu);
}
if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) {
printk(KERN_ERR "ERROR: domain->groups does not contain"
" CPU%d\n", cpu);
}

printk(KERN_DEBUG "%*s groups:", level + 1, "");
do {
if (!group) {
printk("\n");
printk(KERN_ERR "ERROR: group is NULL\n");
break;
}

if (!group->sgp->power) {
printk(KERN_CONT "\n");
printk(KERN_ERR "ERROR: domain->cpu_power not "
"set\n");
break;
}

if (!cpumask_weight(sched_group_cpus(group))) {
printk(KERN_CONT "\n");
printk(KERN_ERR "ERROR: empty group\n");
break;
}

if (cpumask_intersects(groupmask, sched_group_cpus(group))) {
printk(KERN_CONT "\n");
printk(KERN_ERR "ERROR: repeated CPUs\n");
break;
}

cpumask_or(groupmask, groupmask, sched_group_cpus(group));

cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));

printk(KERN_CONT " %s", str);
if (group->sgp->power != SCHED_POWER_SCALE) {
printk(KERN_CONT " (cpu_power = %d)",
group->sgp->power);
}

group = group->next;
} while (group != sd->groups);
printk(KERN_CONT "\n");

if (!cpumask_equal(sched_domain_span(sd), groupmask))
printk(KERN_ERR "ERROR: groups don't span domain->span\n");

if (sd->parent &&
!cpumask_subset(groupmask, sched_domain_span(sd->parent)))
printk(KERN_ERR "ERROR: parent span is not a superset "
"of domain->span\n");
return 0;
}

static void sched_domain_debug(struct sched_domain *sd, int cpu)
{
int level = 0;

if (!sched_domain_debug_enabled)
return;

if (!sd) {
printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
return;
}

printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);

for (;;) {
if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask))
break;
level++;
sd = sd->parent;
if (!sd)
break;
}
}
#else /* !CONFIG_SCHED_DEBUG */
# define sched_domain_debug(sd, cpu) do { } while (0)
#endif /* CONFIG_SCHED_DEBUG */

static int sd_degenerate(struct sched_domain *sd)
{
if (cpumask_weight(sched_domain_span(sd)) == 1)
return 1;

/* Following flags need at least 2 groups */
if (sd->flags & (SD_LOAD_BALANCE |
SD_BALANCE_NEWIDLE |
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
SD_SHARE_CPUPOWER |
SD_SHARE_PKG_RESOURCES)) {
if (sd->groups != sd->groups->next)
return 0;
}

/* Following flags don't use groups */
if (sd->flags & (SD_WAKE_AFFINE))
return 0;

return 1;
}

static int
sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
{
unsigned long cflags = sd->flags, pflags = parent->flags;

if (sd_degenerate(parent))
return 1;

if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent)))
return 0;

/* Flags needing groups don't count if only 1 group in parent */
if (parent->groups == parent->groups->next) {
pflags &= ~(SD_LOAD_BALANCE |
SD_BALANCE_NEWIDLE |
SD_BALANCE_FORK |
SD_BALANCE_EXEC |
SD_SHARE_CPUPOWER |
SD_SHARE_PKG_RESOURCES);
if (nr_node_ids == 1)
pflags &= ~SD_SERIALIZE;
}
if (~cflags & pflags)
return 0;

return 1;
}

static void free_rootdomain(struct rcu_head *rcu)
{
struct root_domain *rd = container_of(rcu, struct root_domain, rcu);

cpupri_cleanup(&rd->cpupri);
free_cpumask_var(rd->rto_mask);
free_cpumask_var(rd->online);
free_cpumask_var(rd->span);
kfree(rd);
}

static void rq_attach_root(struct rq *rq, struct root_domain *rd)
{
struct root_domain *old_rd = NULL;
unsigned long flags;

grq_lock_irqsave(&flags);

if (rq->rd) {
old_rd = rq->rd;

if (cpumask_test_cpu(rq->cpu, old_rd->online))
set_rq_offline(rq);

cpumask_clear_cpu(rq->cpu, old_rd->span);

/*
* If we dont want to free the old_rt yet then
* set old_rd to NULL to skip the freeing later
* in this function:
*/
if (!atomic_dec_and_test(&old_rd->refcount))
old_rd = NULL;
}

atomic_inc(&rd->refcount);
rq->rd = rd;

cpumask_set_cpu(rq->cpu, rd->span);
if (cpumask_test_cpu(rq->cpu, cpu_active_mask))
set_rq_online(rq);

grq_unlock_irqrestore(&flags);

if (old_rd)
call_rcu_sched(&old_rd->rcu, free_rootdomain);
}

static int init_rootdomain(struct root_domain *rd)
{
memset(rd, 0, sizeof(*rd));

if (!alloc_cpumask_var(&rd->span, GFP_KERNEL))
goto out;
if (!alloc_cpumask_var(&rd->online, GFP_KERNEL))
goto free_span;
if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL))
goto free_online;

if (cpupri_init(&rd->cpupri) != 0)
goto free_rto_mask;
return 0;

free_rto_mask:
free_cpumask_var(rd->rto_mask);
free_online:
free_cpumask_var(rd->online);
free_span:
free_cpumask_var(rd->span);
out:
return -ENOMEM;
}

static void init_defrootdomain(void)
{
init_rootdomain(&def_root_domain);

atomic_set(&def_root_domain.refcount, 1);
}

static struct root_domain *alloc_rootdomain(void)
{
struct root_domain *rd;

rd = kmalloc(sizeof(*rd), GFP_KERNEL);
if (!rd)
return NULL;

if (init_rootdomain(rd) != 0) {
kfree(rd);
return NULL;
}

return rd;
}

static void free_sched_groups(struct sched_group *sg, int free_sgp)
{
struct sched_group *tmp, *first;

if (!sg)
return;

first = sg;
do {
tmp = sg->next;

if (free_sgp && atomic_dec_and_test(&sg->sgp->ref))
kfree(sg->sgp);

kfree(sg);
sg = tmp;
} while (sg != first);
}

static void free_sched_domain(struct rcu_head *rcu)
{
struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu);

/*
* If its an overlapping domain it has private groups, iterate and
* nuke them all.
*/
if (sd->flags & SD_OVERLAP) {
free_sched_groups(sd->groups, 1);
} else if (atomic_dec_and_test(&sd->groups->ref)) {
kfree(sd->groups->sgp);
kfree(sd->groups);
}
kfree(sd);
}

static void destroy_sched_domain(struct sched_domain *sd, int cpu)
{
call_rcu(&sd->rcu, free_sched_domain);
}

static void destroy_sched_domains(struct sched_domain *sd, int cpu)
{
for (; sd; sd = sd->parent)
destroy_sched_domain(sd, cpu);
}

/*
* Attach the domain 'sd' to 'cpu' as its base domain. Callers must
* hold the hotplug lock.
*/
static void
cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
{
struct rq *rq = cpu_rq(cpu);
struct sched_domain *tmp;

/* Remove the sched domains which do not contribute to scheduling. */
for (tmp = sd; tmp; ) {
struct sched_domain *parent = tmp->parent;
if (!parent)
break;

if (sd_parent_degenerate(tmp, parent)) {
tmp->parent = parent->parent;
if (parent->parent)
parent->parent->child = tmp;
destroy_sched_domain(parent, cpu);
} else
tmp = tmp->parent;
}

if (sd && sd_degenerate(sd)) {
tmp = sd;
sd = sd->parent;
destroy_sched_domain(tmp, cpu);
if (sd)
sd->child = NULL;
}

sched_domain_debug(sd, cpu);

rq_attach_root(rq, rd);
tmp = rq->sd;
rcu_assign_pointer(rq->sd, sd);
destroy_sched_domains(tmp, cpu);
}

/* cpus with isolated domains */
static cpumask_var_t cpu_isolated_map;

/* Setup the mask of cpus configured for isolated domains */
static int __init isolated_cpu_setup(char *str)
{
alloc_bootmem_cpumask_var(&cpu_isolated_map);
cpulist_parse(str, cpu_isolated_map);
return 1;
}

__setup("isolcpus=", isolated_cpu_setup);

#define SD_NODES_PER_DOMAIN 16

#ifdef CONFIG_NUMA

/**
* find_next_best_node - find the next node to include in a sched_domain
* @node: node whose sched_domain we're building
* @used_nodes: nodes already in the sched_domain
*
* Find the next node to include in a given scheduling domain. Simply
* finds the closest node not already in the @used_nodes map.
*
* Should use nodemask_t.
*/
static int find_next_best_node(int node, nodemask_t *used_nodes)
{
int i, n, val, min_val, best_node = -1;

min_val = INT_MAX;

for (i = 0; i < nr_node_ids; i++) {
/* Start at @node */
n = (node + i) % nr_node_ids;

if (!nr_cpus_node(n))
continue;

/* Skip already used nodes */
if (node_isset(n, *used_nodes))
continue;

/* Simple min distance search */
val = node_distance(node, n);

if (val < min_val) {
min_val = val;
best_node = n;
}
}

if (best_node != -1)
node_set(best_node, *used_nodes);
return best_node;
}

/**
* sched_domain_node_span - get a cpumask for a node's sched_domain
* @node: node whose cpumask we're constructing
* @span: resulting cpumask
*
* Given a node, construct a good cpumask for its sched_domain to span. It
* should be one that prevents unnecessary balancing, but also spreads tasks
* out optimally.
*/
static void sched_domain_node_span(int node, struct cpumask *span)
{
nodemask_t used_nodes;
int i;

cpumask_clear(span);
nodes_clear(used_nodes);

cpumask_or(span, span, cpumask_of_node(node));
node_set(node, used_nodes);

for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
int next_node = find_next_best_node(node, &used_nodes);
if (next_node < 0)
break;
cpumask_or(span, span, cpumask_of_node(next_node));
}
}

static const struct cpumask *cpu_node_mask(int cpu)
{
lockdep_assert_held(&sched_domains_mutex);

sched_domain_node_span(cpu_to_node(cpu), sched_domains_tmpmask);

return sched_domains_tmpmask;
}

static const struct cpumask *cpu_allnodes_mask(int cpu)
{
return cpu_possible_mask;
}
#endif /* CONFIG_NUMA */

static const struct cpumask *cpu_cpu_mask(int cpu)
{
return cpumask_of_node(cpu_to_node(cpu));
}

int sched_smt_power_savings = 0, sched_mc_power_savings = 0;

struct sd_data {
struct sched_domain **__percpu sd;
struct sched_group **__percpu sg;
struct sched_group_power **__percpu sgp;
};

struct s_data {
struct sched_domain ** __percpu sd;
struct root_domain *rd;
};

enum s_alloc {
sa_rootdomain,
sa_sd,
sa_sd_storage,
sa_none,
};

struct sched_domain_topology_level;

typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu);
typedef const struct cpumask *(*sched_domain_mask_f)(int cpu);

#define SDTL_OVERLAP 0x01

struct sched_domain_topology_level {
sched_domain_init_f init;
sched_domain_mask_f mask;
int flags;
struct sd_data data;
};

static int
build_overlap_sched_groups(struct sched_domain *sd, int cpu)
{
struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg;
const struct cpumask *span = sched_domain_span(sd);
struct cpumask *covered = sched_domains_tmpmask;
struct sd_data *sdd = sd->private;
struct sched_domain *child;
int i;

cpumask_clear(covered);

for_each_cpu(i, span) {
struct cpumask *sg_span;

if (cpumask_test_cpu(i, covered))
continue;

sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
GFP_KERNEL, cpu_to_node(i));

if (!sg)
goto fail;

sg_span = sched_group_cpus(sg);

child = *per_cpu_ptr(sdd->sd, i);
if (child->child) {
child = child->child;
cpumask_copy(sg_span, sched_domain_span(child));
} else
cpumask_set_cpu(i, sg_span);

cpumask_or(covered, covered, sg_span);

sg->sgp = *per_cpu_ptr(sdd->sgp, cpumask_first(sg_span));
atomic_inc(&sg->sgp->ref);

if (cpumask_test_cpu(cpu, sg_span))
groups = sg;

if (!first)
first = sg;
if (last)
last->next = sg;
last = sg;
last->next = first;
}
sd->groups = groups;

return 0;

fail:
free_sched_groups(first, 0);

return -ENOMEM;
}

static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)
{
struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);
struct sched_domain *child = sd->child;

if (child)
cpu = cpumask_first(sched_domain_span(child));

if (sg) {
*sg = *per_cpu_ptr(sdd->sg, cpu);
(*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu);
atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */
}

return cpu;
}

/*
* build_sched_groups will build a circular linked list of the groups
* covered by the given span, and will set each group's ->cpumask correctly,
* and ->cpu_power to 0.
*
* Assumes the sched_domain tree is fully constructed
*/
static int
build_sched_groups(struct sched_domain *sd, int cpu)
{
struct sched_group *first = NULL, *last = NULL;
struct sd_data *sdd = sd->private;
const struct cpumask *span = sched_domain_span(sd);
struct cpumask *covered;
int i;

get_group(cpu, sdd, &sd->groups);
atomic_inc(&sd->groups->ref);

if (cpu != cpumask_first(sched_domain_span(sd)))
return 0;

lockdep_assert_held(&sched_domains_mutex);
covered = sched_domains_tmpmask;

cpumask_clear(covered);

for_each_cpu(i, span) {
struct sched_group *sg;
int group = get_group(i, sdd, &sg);
int j;

if (cpumask_test_cpu(i, covered))
continue;

cpumask_clear(sched_group_cpus(sg));
sg->sgp->power = 0;

for_each_cpu(j, span) {
if (get_group(j, sdd, NULL) != group)
continue;

cpumask_set_cpu(j, covered);
cpumask_set_cpu(j, sched_group_cpus(sg));
}

if (!first)
first = sg;
if (last)
last->next = sg;
last = sg;
}
last->next = first;

return 0;
}

/*
* Initializers for schedule domains
* Non-inlined to reduce accumulated stack pressure in build_sched_domains()
*/

#ifdef CONFIG_SCHED_DEBUG
# define SD_INIT_NAME(sd, type) sd->name = #type
#else
# define SD_INIT_NAME(sd, type) do { } while (0)
#endif

#define SD_INIT_FUNC(type) \
static noinline struct sched_domain * \
sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \
{ \
struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \
*sd = SD_##type##_INIT; \
SD_INIT_NAME(sd, type); \
sd->private = &tl->data; \
return sd; \
}

SD_INIT_FUNC(CPU)
#ifdef CONFIG_NUMA
SD_INIT_FUNC(ALLNODES)
SD_INIT_FUNC(NODE)
#endif
#ifdef CONFIG_SCHED_SMT
SD_INIT_FUNC(SIBLING)
#endif
#ifdef CONFIG_SCHED_MC
SD_INIT_FUNC(MC)
#endif
#ifdef CONFIG_SCHED_BOOK
SD_INIT_FUNC(BOOK)
#endif

static int default_relax_domain_level = -1;
int sched_domain_level_max;

static int __init setup_relax_domain_level(char *str)
{
unsigned long val;

val = simple_strtoul(str, NULL, 0);
if (val < sched_domain_level_max)
default_relax_domain_level = val;

return 1;
}
__setup("relax_domain_level=", setup_relax_domain_level);

static void set_domain_attribute(struct sched_domain *sd,
struct sched_domain_attr *attr)
{
int request;

if (!attr || attr->relax_domain_level < 0) {
if (default_relax_domain_level < 0)
return;
else
request = default_relax_domain_level;
} else
request = attr->relax_domain_level;
if (request < sd->level) {
/* turn off idle balance on this domain */
sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
} else {
/* turn on idle balance on this domain */
sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE);
}
}

static void __sdt_free(const struct cpumask *cpu_map);
static int __sdt_alloc(const struct cpumask *cpu_map);

static void __free_domain_allocs(struct s_data *d, enum s_alloc what,
const struct cpumask *cpu_map)
{
switch (what) {
case sa_rootdomain:
if (!atomic_read(&d->rd->refcount))
free_rootdomain(&d->rd->rcu); /* fall through */
case sa_sd:
free_percpu(d->sd); /* fall through */
case sa_sd_storage:
__sdt_free(cpu_map); /* fall through */
case sa_none:
break;
}
}

static enum s_alloc __visit_domain_allocation_hell(struct s_data *d,
const struct cpumask *cpu_map)
{
memset(d, 0, sizeof(*d));

if (__sdt_alloc(cpu_map))
return sa_sd_storage;
d->sd = alloc_percpu(struct sched_domain *);
if (!d->sd)
return sa_sd_storage;
d->rd = alloc_rootdomain();
if (!d->rd)
return sa_sd;
return sa_rootdomain;
}

/*
* NULL the sd_data elements we've used to build the sched_domain and
* sched_group structure so that the subsequent __free_domain_allocs()
* will not free the data we're using.
*/
static void claim_allocations(int cpu, struct sched_domain *sd)
{
struct sd_data *sdd = sd->private;

WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd);
*per_cpu_ptr(sdd->sd, cpu) = NULL;

if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref))
*per_cpu_ptr(sdd->sg, cpu) = NULL;

if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref))
*per_cpu_ptr(sdd->sgp, cpu) = NULL;
}

#ifdef CONFIG_SCHED_SMT
static const struct cpumask *cpu_smt_mask(int cpu)
{
return topology_thread_cpumask(cpu);
}
#endif

/*
* Topology list, bottom-up.
*/
static struct sched_domain_topology_level default_topology[] = {
#ifdef CONFIG_SCHED_SMT
{ sd_init_SIBLING, cpu_smt_mask, },
#endif
#ifdef CONFIG_SCHED_MC
{ sd_init_MC, cpu_coregroup_mask, },
#endif
#ifdef CONFIG_SCHED_BOOK
{ sd_init_BOOK, cpu_book_mask, },
#endif
{ sd_init_CPU, cpu_cpu_mask, },
#ifdef CONFIG_NUMA
{ sd_init_NODE, cpu_node_mask, SDTL_OVERLAP, },
{ sd_init_ALLNODES, cpu_allnodes_mask, },
#endif
{ NULL, },
};

static struct sched_domain_topology_level *sched_domain_topology = default_topology;

static int __sdt_alloc(const struct cpumask *cpu_map)
{
struct sched_domain_topology_level *tl;
int j;

for (tl = sched_domain_topology; tl->init; tl++) {
struct sd_data *sdd = &tl->data;

sdd->sd = alloc_percpu(struct sched_domain *);
if (!sdd->sd)
return -ENOMEM;

sdd->sg = alloc_percpu(struct sched_group *);
if (!sdd->sg)
return -ENOMEM;

sdd->sgp = alloc_percpu(struct sched_group_power *);
if (!sdd->sgp)
return -ENOMEM;

for_each_cpu(j, cpu_map) {
struct sched_domain *sd;
struct sched_group *sg;
struct sched_group_power *sgp;

sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(),
GFP_KERNEL, cpu_to_node(j));
if (!sd)
return -ENOMEM;

*per_cpu_ptr(sdd->sd, j) = sd;

sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(),
GFP_KERNEL, cpu_to_node(j));
if (!sg)
return -ENOMEM;

*per_cpu_ptr(sdd->sg, j) = sg;

sgp = kzalloc_node(sizeof(struct sched_group_power),
GFP_KERNEL, cpu_to_node(j));
if (!sgp)
return -ENOMEM;

*per_cpu_ptr(sdd->sgp, j) = sgp;
}
}

return 0;
}

static void __sdt_free(const struct cpumask *cpu_map)
{
struct sched_domain_topology_level *tl;
int j;

for (tl = sched_domain_topology; tl->init; tl++) {
struct sd_data *sdd = &tl->data;

for_each_cpu(j, cpu_map) {
struct sched_domain *sd = *per_cpu_ptr(sdd->sd, j);
if (sd && (sd->flags & SD_OVERLAP))
free_sched_groups(sd->groups, 0);
kfree(*per_cpu_ptr(sdd->sd, j));
kfree(*per_cpu_ptr(sdd->sg, j));
kfree(*per_cpu_ptr(sdd->sgp, j));
}
free_percpu(sdd->sd);
free_percpu(sdd->sg);
free_percpu(sdd->sgp);
}
}

struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl,
struct s_data *d, const struct cpumask *cpu_map,
struct sched_domain_attr *attr, struct sched_domain *child,
int cpu)
{
struct sched_domain *sd = tl->init(tl, cpu);
if (!sd)
return child;

set_domain_attribute(sd, attr);
cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu));
if (child) {
sd->level = child->level + 1;
sched_domain_level_max = max(sched_domain_level_max, sd->level);
child->parent = sd;
}
sd->child = child;

return sd;
}

/*
* Build sched domains for a given set of cpus and attach the sched domains
* to the individual cpus
*/
static int build_sched_domains(const struct cpumask *cpu_map,
struct sched_domain_attr *attr)
{
enum s_alloc alloc_state = sa_none;
struct sched_domain *sd;
struct s_data d;
int i, ret = -ENOMEM;

alloc_state = __visit_domain_allocation_hell(&d, cpu_map);
if (alloc_state != sa_rootdomain)
goto error;

/* Set up domains for cpus specified by the cpu_map. */
for_each_cpu(i, cpu_map) {
struct sched_domain_topology_level *tl;

sd = NULL;
for (tl = sched_domain_topology; tl->init; tl++) {
sd = build_sched_domain(tl, &d, cpu_map, attr, sd, i);
if (tl->flags & SDTL_OVERLAP)
sd->flags |= SD_OVERLAP;
if (cpumask_equal(cpu_map, sched_domain_span(sd)))
break;
}

while (sd->child)
sd = sd->child;

*per_cpu_ptr(d.sd, i) = sd;
}

/* Build the groups for the domains */
for_each_cpu(i, cpu_map) {
for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
sd->span_weight = cpumask_weight(sched_domain_span(sd));
if (sd->flags & SD_OVERLAP) {
if (build_overlap_sched_groups(sd, i))
goto error;
} else {
if (build_sched_groups(sd, i))
goto error;
}
}
}

/* Calculate CPU power for physical packages and nodes */
for (i = nr_cpumask_bits-1; i >= 0; i--) {
if (!cpumask_test_cpu(i, cpu_map))
continue;

for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) {
claim_allocations(i, sd);
}
}

/* Attach the domains */
rcu_read_lock();
for_each_cpu(i, cpu_map) {
sd = *per_cpu_ptr(d.sd, i);
cpu_attach_domain(sd, d.rd, i);
}
rcu_read_unlock();

ret = 0;
error:
__free_domain_allocs(&d, alloc_state, cpu_map);
return ret;
}

static cpumask_var_t *doms_cur; /* current sched domains */
static int ndoms_cur; /* number of sched domains in 'doms_cur' */
static struct sched_domain_attr *dattr_cur;
/* attribues of custom domains in 'doms_cur' */

/*
* Special case: If a kmalloc of a doms_cur partition (array of
* cpumask) fails, then fallback to a single sched domain,
* as determined by the single cpumask fallback_doms.
*/
static cpumask_var_t fallback_doms;

/*
* arch_update_cpu_topology lets virtualized architectures update the
* cpu core maps. It is supposed to return 1 if the topology changed
* or 0 if it stayed the same.
*/
int __attribute__((weak)) arch_update_cpu_topology(void)
{
return 0;
}

cpumask_var_t *alloc_sched_domains(unsigned int ndoms)
{
int i;
cpumask_var_t *doms;

doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL);
if (!doms)
return NULL;
for (i = 0; i < ndoms; i++) {
if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) {
free_sched_domains(doms, i);
return NULL;
}
}
return doms;
}

void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms)
{
unsigned int i;
for (i = 0; i < ndoms; i++)
free_cpumask_var(doms[i]);
kfree(doms);
}

/*
* Set up scheduler domains and groups. Callers must hold the hotplug lock.
* For now this just excludes isolated cpus, but could be used to
* exclude other special cases in the future.
*/
static int init_sched_domains(const struct cpumask *cpu_map)
{
int err;

arch_update_cpu_topology();
ndoms_cur = 1;
doms_cur = alloc_sched_domains(ndoms_cur);
if (!doms_cur)
doms_cur = &fallback_doms;
cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map);
dattr_cur = NULL;
err = build_sched_domains(doms_cur[0], NULL);
register_sched_domain_sysctl();

return err;
}

/*
* Detach sched domains from a group of cpus specified in cpu_map
* These cpus will now be attached to the NULL domain
*/
static void detach_destroy_domains(const struct cpumask *cpu_map)
{
int i;

rcu_read_lock();
for_each_cpu(i, cpu_map)
cpu_attach_domain(NULL, &def_root_domain, i);
rcu_read_unlock();
}

/* handle null as "default" */
static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
struct sched_domain_attr *new, int idx_new)
{
struct sched_domain_attr tmp;

/* fast path */
if (!new && !cur)
return 1;

tmp = SD_ATTR_INIT;
return !memcmp(cur ? (cur + idx_cur) : &tmp,
new ? (new + idx_new) : &tmp,
sizeof(struct sched_domain_attr));
}

/*
* Partition sched domains as specified by the 'ndoms_new'
* cpumasks in the array doms_new[] of cpumasks. This compares
* doms_new[] to the current sched domain partitioning, doms_cur[].
* It destroys each deleted domain and builds each new domain.
*
* 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'.
* The masks don't intersect (don't overlap.) We should setup one
* sched domain for each mask. CPUs not in any of the cpumasks will
* not be load balanced. If the same cpumask appears both in the
* current 'doms_cur' domains and in the new 'doms_new', we can leave
* it as it is.
*
* The passed in 'doms_new' should be allocated using
* alloc_sched_domains. This routine takes ownership of it and will
* free_sched_domains it when done with it. If the caller failed the
* alloc call, then it can pass in doms_new == NULL && ndoms_new == 1,
* and partition_sched_domains() will fallback to the single partition
* 'fallback_doms', it also forces the domains to be rebuilt.
*
* If doms_new == NULL it will be replaced with cpu_online_mask.
* ndoms_new == 0 is a special case for destroying existing domains,
* and it will not create the default domain.
*
* Call with hotplug lock held
*/
void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
int i, j, n;
int new_topology;

mutex_lock(&sched_domains_mutex);

/* always unregister in case we don't destroy any domains */
unregister_sched_domain_sysctl();

/* Let architecture update cpu core mappings. */
new_topology = arch_update_cpu_topology();

n = doms_new ? ndoms_new : 0;

/* Destroy deleted domains */
for (i = 0; i < ndoms_cur; i++) {
for (j = 0; j < n && !new_topology; j++) {
if (cpumask_equal(doms_cur[i], doms_new[j])
&& dattrs_equal(dattr_cur, i, dattr_new, j))
goto match1;
}
/* no match - a current sched domain not in new doms_new[] */
detach_destroy_domains(doms_cur[i]);
match1:
;
}

if (doms_new == NULL) {
ndoms_cur = 0;
doms_new = &fallback_doms;
cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map);
WARN_ON_ONCE(dattr_new);
}

/* Build new domains */
for (i = 0; i < ndoms_new; i++) {
for (j = 0; j < ndoms_cur && !new_topology; j++) {
if (cpumask_equal(doms_new[i], doms_cur[j])
&& dattrs_equal(dattr_new, i, dattr_cur, j))
goto match2;
}
/* no match - add a new doms_new */
build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL);
match2:
;
}

/* Remember the new sched domains */
if (doms_cur != &fallback_doms)
free_sched_domains(doms_cur, ndoms_cur);
kfree(dattr_cur); /* kfree(NULL) is safe */
doms_cur = doms_new;
dattr_cur = dattr_new;
ndoms_cur = ndoms_new;

register_sched_domain_sysctl();

mutex_unlock(&sched_domains_mutex);
}

#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
static void reinit_sched_domains(void)
{
get_online_cpus();

/* Destroy domains first to force the rebuild */
partition_sched_domains(0, NULL, NULL);

rebuild_sched_domains();
put_online_cpus();
}

static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
{
unsigned int level = 0;

if (sscanf(buf, "%u", &level) != 1)
return -EINVAL;

/*
* level is always be positive so don't check for
* level < POWERSAVINGS_BALANCE_NONE which is 0
* What happens on 0 or 1 byte write,
* need to check for count as well?
*/

if (level >= MAX_POWERSAVINGS_BALANCE_LEVELS)
return -EINVAL;

if (smt)
sched_smt_power_savings = level;
else
sched_mc_power_savings = level;

reinit_sched_domains();

return count;
}

#ifdef CONFIG_SCHED_MC
static ssize_t sched_mc_power_savings_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", sched_mc_power_savings);
}
static ssize_t sched_mc_power_savings_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
return sched_power_savings_store(buf, count, 0);
}
static DEVICE_ATTR(sched_mc_power_savings, 0644,
sched_mc_power_savings_show,
sched_mc_power_savings_store);
#endif

#ifdef CONFIG_SCHED_SMT
static ssize_t sched_smt_power_savings_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
return sprintf(buf, "%u\n", sched_smt_power_savings);
}
static ssize_t sched_smt_power_savings_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
return sched_power_savings_store(buf, count, 1);
}
static DEVICE_ATTR(sched_smt_power_savings, 0644,
sched_smt_power_savings_show,
sched_smt_power_savings_store);
#endif

int __init sched_create_sysfs_power_savings_entries(struct device *dev)
{
int err = 0;

#ifdef CONFIG_SCHED_SMT
if (smt_capable())
err = device_create_file(dev, &dev_attr_sched_smt_power_savings);
#endif
#ifdef CONFIG_SCHED_MC
if (!err && mc_capable())
err = device_create_file(dev, &dev_attr_sched_mc_power_savings);
#endif
return err;
}
#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */

/*
* Update cpusets according to cpu_active mask. If cpusets are
* disabled, cpuset_update_active_cpus() becomes a simple wrapper
* around partition_sched_domains().
*/
static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action,
void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_ONLINE:
case CPU_DOWN_FAILED:
cpuset_update_active_cpus();
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}

static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action,
void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
case CPU_DOWN_PREPARE:
cpuset_update_active_cpus();
return NOTIFY_OK;
default:
return NOTIFY_DONE;
}
}

#if defined(CONFIG_SCHED_SMT) || defined(CONFIG_SCHED_MC)
/*
* Cheaper version of the below functions in case support for SMT and MC is
* compiled in but CPUs have no siblings.
*/
static bool sole_cpu_idle(int cpu)
{
return rq_idle(cpu_rq(cpu));
}
#endif
#ifdef CONFIG_SCHED_SMT
/* All this CPU's SMT siblings are idle */
static bool siblings_cpu_idle(int cpu)
{
return cpumask_subset(&(cpu_rq(cpu)->smt_siblings),
&grq.cpu_idle_map);
}
#endif
#ifdef CONFIG_SCHED_MC
/* All this CPU's shared cache siblings are idle */
static bool cache_cpu_idle(int cpu)
{
return cpumask_subset(&(cpu_rq(cpu)->cache_siblings),
&grq.cpu_idle_map);
}
#endif

enum sched_domain_level {
SD_LV_NONE = 0,
SD_LV_SIBLING,
SD_LV_MC,
SD_LV_BOOK,
SD_LV_CPU,
SD_LV_NODE,
SD_LV_ALLNODES,
SD_LV_MAX
};

void __init sched_init_smp(void)
{
struct sched_domain *sd;
int cpu;

cpumask_var_t non_isolated_cpus;

alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL);
alloc_cpumask_var(&fallback_doms, GFP_KERNEL);

get_online_cpus();
mutex_lock(&sched_domains_mutex);
init_sched_domains(cpu_active_mask);
cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map);
if (cpumask_empty(non_isolated_cpus))
cpumask_set_cpu(smp_processor_id(), non_isolated_cpus);
mutex_unlock(&sched_domains_mutex);
put_online_cpus();

hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE);
hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE);

/* Move init over to a non-isolated CPU */
if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0)
BUG();
free_cpumask_var(non_isolated_cpus);

grq_lock_irq();
/*
* Set up the relative cache distance of each online cpu from each
* other in a simple array for quick lookup. Locality is determined
* by the closest sched_domain that CPUs are separated by. CPUs with
* shared cache in SMT and MC are treated as local. Separate CPUs
* (within the same package or physically) within the same node are
* treated as not local. CPUs not even in the same domain (different
* nodes) are treated as very distant.
*/
for_each_online_cpu(cpu) {
struct rq *rq = cpu_rq(cpu);
for_each_domain(cpu, sd) {
int locality, other_cpu;

#ifdef CONFIG_SCHED_SMT
if (sd->level == SD_LV_SIBLING) {
for_each_cpu_mask(other_cpu, *sched_domain_span(sd))
cpumask_set_cpu(other_cpu, &rq->smt_siblings);
}
#endif
#ifdef CONFIG_SCHED_MC
if (sd->level == SD_LV_MC) {
for_each_cpu_mask(other_cpu, *sched_domain_span(sd))
cpumask_set_cpu(other_cpu, &rq->cache_siblings);
}
#endif
if (sd->level <= SD_LV_SIBLING)
locality = 1;
else if (sd->level <= SD_LV_MC)
locality = 2;
else if (sd->level <= SD_LV_NODE)
locality = 3;
else
continue;

for_each_cpu_mask(other_cpu, *sched_domain_span(sd)) {
if (locality < rq->cpu_locality[other_cpu])
rq->cpu_locality[other_cpu] = locality;
}
}

/*
* Each runqueue has its own function in case it doesn't have
* siblings of its own allowing mixed topologies.
*/
#ifdef CONFIG_SCHED_SMT
if (cpus_weight(rq->smt_siblings) > 1)
rq->siblings_idle = siblings_cpu_idle;
#endif
#ifdef CONFIG_SCHED_MC
if (cpus_weight(rq->cache_siblings) > 1)
rq->cache_idle = cache_cpu_idle;
#endif
}
grq_unlock_irq();
}
#else
void __init sched_init_smp(void)
{
}
#endif /* CONFIG_SMP */

unsigned int sysctl_timer_migration = 1;

int in_sched_functions(unsigned long addr)
{
return in_lock_functions(addr) ||
(addr >= (unsigned long)__sched_text_start
&& addr < (unsigned long)__sched_text_end);
}

void __init sched_init(void)
{
int i;
struct rq *rq;

print_scheduler_version();

raw_spin_lock_init(&grq.lock);
grq.nr_running = grq.nr_uninterruptible = grq.nr_switches = 0;
grq.niffies = 0;
grq.last_jiffy = jiffies;
grq.noc = 1;
#ifdef CONFIG_SMP
init_defrootdomain();
grq.qnr = grq.idle_cpus = 0;
cpumask_clear(&grq.cpu_idle_map);
#else
uprq = &per_cpu(runqueues, 0);
#endif
for_each_possible_cpu(i) {
rq = cpu_rq(i);
rq->user_pc = rq->nice_pc = rq->softirq_pc = rq->system_pc =
rq->iowait_pc = rq->idle_pc = 0;
#ifdef CONFIG_SMP
rq->sticky_task = NULL;
rq->last_niffy = 0;
rq->sd = NULL;
rq->rd = NULL;
rq->online = false;
rq->cpu = i;
rq_attach_root(rq, &def_root_domain);
#endif
atomic_set(&rq->nr_iowait, 0);
}

#ifdef CONFIG_SMP
nr_cpu_ids = i;
/*
* Set the base locality for cpu cache distance calculation to
* "distant" (3). Make sure the distance from a CPU to itself is 0.
*/
for_each_possible_cpu(i) {
int j;

rq = cpu_rq(i);
#ifdef CONFIG_SCHED_SMT
cpumask_clear(&rq->smt_siblings);
cpumask_set_cpu(i, &rq->smt_siblings);
rq->siblings_idle = sole_cpu_idle;
cpumask_set_cpu(i, &rq->smt_siblings);
#endif
#ifdef CONFIG_SCHED_MC
cpumask_clear(&rq->cache_siblings);
cpumask_set_cpu(i, &rq->cache_siblings);
rq->cache_idle = sole_cpu_idle;
cpumask_set_cpu(i, &rq->cache_siblings);
#endif
rq->cpu_locality = kmalloc(nr_cpu_ids * sizeof(int *), GFP_ATOMIC);
for_each_possible_cpu(j) {
if (i == j)
rq->cpu_locality[j] = 0;
else
rq->cpu_locality[j] = 4;
}
}
#endif

for (i = 0; i < PRIO_LIMIT; i++)
INIT_LIST_HEAD(grq.queue + i);
/* delimiter for bitsearch */
__set_bit(PRIO_LIMIT, grq.prio_bitmap);

#ifdef CONFIG_PREEMPT_NOTIFIERS
INIT_HLIST_HEAD(&init_task.preempt_notifiers);
#endif

#ifdef CONFIG_RT_MUTEXES
plist_head_init(&init_task.pi_waiters);
#endif

/*
* The boot idle thread does lazy MMU switching as well:
*/
atomic_inc(&init_mm.mm_count);
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());

#ifdef CONFIG_SMP
zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT);
/* May be allocated at isolcpus cmdline parse time */
if (cpu_isolated_map == NULL)
zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT);
#endif /* SMP */
}

#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
static inline int preempt_count_equals(int preempt_offset)
{
int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth();

return (nested == preempt_offset);
}

void __might_sleep(const char *file, int line, int preempt_offset)
{
static unsigned long prev_jiffy; /* ratelimiting */

rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */
if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
system_state != SYSTEM_RUNNING || oops_in_progress)
return;
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
return;
prev_jiffy = jiffies;

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, pid: %d, name: %s\n",
in_atomic(), irqs_disabled(),
current->pid, current->comm);

debug_show_held_locks(current);
if (irqs_disabled())
print_irqtrace_events(current);
dump_stack();
}
EXPORT_SYMBOL(__might_sleep);
#endif

#ifdef CONFIG_MAGIC_SYSRQ
void normalize_rt_tasks(void)
{
struct task_struct *g, *p;
unsigned long flags;
struct rq *rq;
int queued;

read_lock_irq(&tasklist_lock);

do_each_thread(g, p) {
if (!rt_task(p))
continue;

raw_spin_lock_irqsave(&p->pi_lock, flags);
rq = __task_grq_lock(p);

queued = task_queued(p);
if (queued)
dequeue_task(p);
__setscheduler(p, rq, SCHED_NORMAL, 0);
if (queued) {
enqueue_task(p);
try_preempt(p, rq);
}

__task_grq_unlock();
raw_spin_unlock_irqrestore(&p->pi_lock, flags);
} while_each_thread(g, p);

read_unlock_irq(&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!
*/
struct task_struct *curr_task(int cpu)
{
return cpu_curr(cpu);
}

#endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */

#ifdef CONFIG_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 set_curr_task(int cpu, struct task_struct *p)
{
cpu_curr(cpu) = p;
}

#endif

/*
* Use precise platform statistics if available:
*/
#ifdef CONFIG_VIRT_CPU_ACCOUNTING
void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
*ut = p->utime;
*st = p->stime;
}

void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
struct task_cputime cputime;

thread_group_cputime(p, &cputime);

*ut = cputime.utime;
*st = cputime.stime;
}
#else

void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
cputime_t rtime, utime = p->utime, total = utime + p->stime;

rtime = nsecs_to_cputime(p->sched_time);

if (total) {
u64 temp;

temp = (u64)(rtime * utime);
do_div(temp, total);
utime = (cputime_t)temp;
} else
utime = rtime;

/*
* Compare with previous values, to keep monotonicity:
*/
p->prev_utime = max(p->prev_utime, utime);
p->prev_stime = max(p->prev_stime, (rtime - p->prev_utime));

*ut = p->prev_utime;
*st = p->prev_stime;
}

/*
* Must be called with siglock held.
*/
void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st)
{
struct signal_struct *sig = p->signal;
struct task_cputime cputime;
cputime_t rtime, utime, total;

thread_group_cputime(p, &cputime);

total = cputime.utime + cputime.stime;
rtime = nsecs_to_cputime(cputime.sum_exec_runtime);

if (total) {
u64 temp;

temp = (u64)(rtime * cputime.utime);
do_div(temp, total);
utime = (cputime_t)temp;
} else
utime = rtime;

sig->prev_utime = max(sig->prev_utime, utime);
sig->prev_stime = max(sig->prev_stime, (rtime - sig->prev_utime));

*ut = sig->prev_utime;
*st = sig->prev_stime;
}
#endif

inline cputime_t task_gtime(struct task_struct *p)
{
return p->gtime;
}

void __cpuinit init_idle_bootup_task(struct task_struct *idle)
{}

#ifdef CONFIG_SCHED_DEBUG
void proc_sched_show_task(struct task_struct *p, struct seq_file *m)
{}

void proc_sched_set_task(struct task_struct *p)
{}
#endif

#ifdef CONFIG_SMP
unsigned long default_scale_freq_power(struct sched_domain *sd, int cpu)
{
return SCHED_LOAD_SCALE;
}

unsigned long default_scale_smt_power(struct sched_domain *sd, int cpu)
{
unsigned long weight = cpumask_weight(sched_domain_span(sd));
unsigned long smt_gain = sd->smt_gain;

smt_gain /= weight;

return smt_gain;
}
#endif
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