* [PATCH] RIFS cpu scheduler
@ 2012-04-23 9:09 mou Chen
2012-04-23 13:13 ` Hillf Danton
0 siblings, 1 reply; 8+ messages in thread
From: mou Chen @ 2012-04-23 9:09 UTC (permalink / raw)
To: linux-kernel
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. :-)
You can just test the scheduler about the interactivity by compiling
your kernel with -j32 or above, then listen to music and browse
webpage by Firefox.
Have fun.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
2012-04-23 9:09 [PATCH] RIFS cpu scheduler mou Chen
@ 2012-04-23 13:13 ` Hillf Danton
2012-04-23 13:38 ` mou Chen
2012-04-23 13:46 ` mou Chen
0 siblings, 2 replies; 8+ messages in thread
From: Hillf Danton @ 2012-04-23 13:13 UTC (permalink / raw)
To: mou Chen; +Cc: linux-kernel
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?
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
2012-04-23 13:13 ` Hillf Danton
@ 2012-04-23 13:38 ` mou Chen
2012-04-23 13:48 ` mou Chen
2012-04-24 11:57 ` Hillf Danton
2012-04-23 13:46 ` mou Chen
1 sibling, 2 replies; 8+ messages in thread
From: mou Chen @ 2012-04-23 13:38 UTC (permalink / raw)
To: Hillf Danton; +Cc: linux-kernel
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?
The SMP code is the same.The algorithum is different. :-)
I forget to fill the CC.Sorry. :-)
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
2012-04-23 13:13 ` Hillf Danton
2012-04-23 13:38 ` mou Chen
@ 2012-04-23 13:46 ` mou Chen
1 sibling, 0 replies; 8+ messages in thread
From: mou Chen @ 2012-04-23 13:46 UTC (permalink / raw)
To: Hillf Danton; +Cc: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 605 bytes --]
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
:)
[-- Attachment #2: rifs.c --]
[-- Type: text/x-csrc, Size: 168967 bytes --]
/*
* 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(¬ifier->link, ¤t->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(¬ifier->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((¶virt_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(¶virt_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
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
2012-04-23 13:38 ` mou Chen
@ 2012-04-23 13:48 ` mou Chen
2012-04-24 11:57 ` Hillf Danton
1 sibling, 0 replies; 8+ messages in thread
From: mou Chen @ 2012-04-23 13:48 UTC (permalink / raw)
To: linux-kernel
This scheduler is designed for desktop user only.It won't work well on
Batch task scheduling.
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
2012-04-23 13:38 ` mou Chen
2012-04-23 13:48 ` mou Chen
@ 2012-04-24 11:57 ` Hillf Danton
[not found] ` <CANQmPXgUb4UzXfJOTgFD9T=nSFOu7WGvPEmSpFBu-nSThUZaPg@mail.gmail.com>
1 sibling, 1 reply; 8+ messages in thread
From: Hillf Danton @ 2012-04-24 11:57 UTC (permalink / raw)
To: mou Chen; +Cc: linux-kernel
On Mon, Apr 23, 2012 at 9:38 PM, mou Chen <hi3766691@gmail.com> wrote:
>
> The SMP code is the same.The algorithum is different. :-)
>
Then would you please share the output of?
diff -pu bfs-version rifs-version
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
[not found] ` <CANQmPXgUb4UzXfJOTgFD9T=nSFOu7WGvPEmSpFBu-nSThUZaPg@mail.gmail.com>
@ 2012-04-27 8:25 ` mou Chen
2012-04-28 1:38 ` Hillf Danton
0 siblings, 1 reply; 8+ messages in thread
From: mou Chen @ 2012-04-27 8:25 UTC (permalink / raw)
To: Hillf Danton; +Cc: linux-kernel
On Fri, Apr 27, 2012 at 4:10 PM, mou Chen <hi3766691@gmail.com> wrote:
> On Tue, Apr 24, 2012 at 7:57 PM, Hillf Danton <dhillf@gmail.com> wrote:
>> On Mon, Apr 23, 2012 at 9:38 PM, mou Chen <hi3766691@gmail.com> wrote:
>>>
>>> The SMP code is the same.The algorithum is different. :-)
>>>
>> Then would you please share the output of?
>>
>> diff -pu bfs-version rifs-version
>
> No any string "bfs-version" was found.
>
> Also I have just finish rewriting the scheduler's code in a more
> readable way.For example changing goto need_resched to loop, dividing
> workqueue sleep checking in a individual function.
>
> I haven't post the newest code yet. :-(
>
> Chen
Also the thing I want to say is, do not try to increase the clock
frequency.It is a stubid way really and still still many guys think
that it is the way to decrease the latency. :-( Everyone knows that
the latency is measuring that the time needed for waking up a process.
For example, an interactive task sleeps 100ms, then when it continues
running, the process hasn't run for 120 ms on SCHED_A.The process
hasn't run for 101ms when it is running on a SHCED_B kernel and we
would say SCHED_B is more interactive than SCHED_A. So there is not
too much relation between latency and clock frequency.
RIFS is not using any fomula and the algorithum RIFS use is simple and
it works very well with make -j64.There is no lagging with firefox.
:-)
Chen
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH] RIFS cpu scheduler
2012-04-27 8:25 ` mou Chen
@ 2012-04-28 1:38 ` Hillf Danton
0 siblings, 0 replies; 8+ messages in thread
From: Hillf Danton @ 2012-04-28 1:38 UTC (permalink / raw)
To: mou Chen; +Cc: linux-kernel
On Fri, Apr 27, 2012 at 4:25 PM, mou Chen <hi3766691@gmail.com> wrote:
>
> RIFS is not using any fomula and the algorithum RIFS use is simple and
> it works very well with make -j64.There is no lagging with firefox.
>
Yes, and diff -pu bfs.c rifs.c could simplify a few more, right?
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2012-04-28 1:38 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-04-23 9:09 [PATCH] RIFS cpu scheduler mou Chen
2012-04-23 13:13 ` Hillf Danton
2012-04-23 13:38 ` mou Chen
2012-04-23 13:48 ` mou Chen
2012-04-24 11:57 ` Hillf Danton
[not found] ` <CANQmPXgUb4UzXfJOTgFD9T=nSFOu7WGvPEmSpFBu-nSThUZaPg@mail.gmail.com>
2012-04-27 8:25 ` mou Chen
2012-04-28 1:38 ` Hillf Danton
2012-04-23 13:46 ` mou Chen
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