diff options
Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 8140 |
1 files changed, 0 insertions, 8140 deletions
diff --git a/kernel/sched.c b/kernel/sched.c deleted file mode 100644 index 8dcdec6fe0f..00000000000 --- a/kernel/sched.c +++ /dev/null @@ -1,8140 +0,0 @@ -/* - * kernel/sched.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 - */ - -#include <linux/mm.h> -#include <linux/module.h> -#include <linux/nmi.h> -#include <linux/init.h> -#include <linux/uaccess.h> -#include <linux/highmem.h> -#include <linux/smp_lock.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/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/pid_namespace.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/percpu.h> -#include <linux/kthread.h> -#include <linux/seq_file.h> -#include <linux/sysctl.h> -#include <linux/syscalls.h> -#include <linux/times.h> -#include <linux/tsacct_kern.h> -#include <linux/kprobes.h> -#include <linux/delayacct.h> -#include <linux/reciprocal_div.h> -#include <linux/unistd.h> -#include <linux/pagemap.h> -#include <linux/hrtimer.h> - -#include <asm/tlb.h> -#include <asm/irq_regs.h> - -/* - * Scheduler clock - returns current time in nanosec units. - * This is default implementation. - * Architectures and sub-architectures can override this. - */ -unsigned long long __attribute__((weak)) sched_clock(void) -{ - return (unsigned long long)jiffies * (NSEC_PER_SEC / HZ); -} - -/* - * 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)) - -/* - * Helpers for converting nanosecond timing to jiffy resolution - */ -#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ)) - -#define NICE_0_LOAD SCHED_LOAD_SCALE -#define NICE_0_SHIFT SCHED_LOAD_SHIFT - -/* - * These are the 'tuning knobs' of the scheduler: - * - * default timeslice is 100 msecs (used only for SCHED_RR tasks). - * Timeslices get refilled after they expire. - */ -#define DEF_TIMESLICE (100 * HZ / 1000) - -#ifdef CONFIG_SMP -/* - * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) - * Since cpu_power is a 'constant', we can use a reciprocal divide. - */ -static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) -{ - return reciprocal_divide(load, sg->reciprocal_cpu_power); -} - -/* - * Each time a sched group cpu_power is changed, - * we must compute its reciprocal value - */ -static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) -{ - sg->__cpu_power += val; - sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); -} -#endif - -static inline int rt_policy(int policy) -{ - if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR)) - return 1; - return 0; -} - -static inline int task_has_rt_policy(struct task_struct *p) -{ - return rt_policy(p->policy); -} - -/* - * This is the priority-queue data structure of the RT scheduling class: - */ -struct rt_prio_array { - DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ - struct list_head queue[MAX_RT_PRIO]; -}; - -#ifdef CONFIG_GROUP_SCHED - -#include <linux/cgroup.h> - -struct cfs_rq; - -static LIST_HEAD(task_groups); - -/* task group related information */ -struct task_group { -#ifdef CONFIG_CGROUP_SCHED - struct cgroup_subsys_state css; -#endif - -#ifdef CONFIG_FAIR_GROUP_SCHED - /* schedulable entities of this group on each cpu */ - struct sched_entity **se; - /* runqueue "owned" by this group on each cpu */ - struct cfs_rq **cfs_rq; - unsigned long shares; -#endif - -#ifdef CONFIG_RT_GROUP_SCHED - struct sched_rt_entity **rt_se; - struct rt_rq **rt_rq; - - u64 rt_runtime; -#endif - - struct rcu_head rcu; - struct list_head list; -}; - -#ifdef CONFIG_FAIR_GROUP_SCHED -/* Default task group's sched entity on each cpu */ -static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); -/* Default task group's cfs_rq on each cpu */ -static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; - -static struct sched_entity *init_sched_entity_p[NR_CPUS]; -static struct cfs_rq *init_cfs_rq_p[NR_CPUS]; -#endif - -#ifdef CONFIG_RT_GROUP_SCHED -static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); -static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; - -static struct sched_rt_entity *init_sched_rt_entity_p[NR_CPUS]; -static struct rt_rq *init_rt_rq_p[NR_CPUS]; -#endif - -/* task_group_lock serializes add/remove of task groups and also changes to - * a task group's cpu shares. - */ -static DEFINE_SPINLOCK(task_group_lock); - -/* doms_cur_mutex serializes access to doms_cur[] array */ -static DEFINE_MUTEX(doms_cur_mutex); - -#ifdef CONFIG_FAIR_GROUP_SCHED -#ifdef CONFIG_USER_SCHED -# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) -#else -# define INIT_TASK_GROUP_LOAD NICE_0_LOAD -#endif - -static int init_task_group_load = INIT_TASK_GROUP_LOAD; -#endif - -/* Default task group. - * Every task in system belong to this group at bootup. - */ -struct task_group init_task_group = { -#ifdef CONFIG_FAIR_GROUP_SCHED - .se = init_sched_entity_p, - .cfs_rq = init_cfs_rq_p, -#endif - -#ifdef CONFIG_RT_GROUP_SCHED - .rt_se = init_sched_rt_entity_p, - .rt_rq = init_rt_rq_p, -#endif -}; - -/* return group to which a task belongs */ -static inline struct task_group *task_group(struct task_struct *p) -{ - struct task_group *tg; - -#ifdef CONFIG_USER_SCHED - tg = p->user->tg; -#elif defined(CONFIG_CGROUP_SCHED) - tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id), - struct task_group, css); -#else - tg = &init_task_group; -#endif - return tg; -} - -/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ -static inline void set_task_rq(struct task_struct *p, unsigned int cpu) -{ -#ifdef CONFIG_FAIR_GROUP_SCHED - p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; - p->se.parent = task_group(p)->se[cpu]; -#endif - -#ifdef CONFIG_RT_GROUP_SCHED - p->rt.rt_rq = task_group(p)->rt_rq[cpu]; - p->rt.parent = task_group(p)->rt_se[cpu]; -#endif -} - -static inline void lock_doms_cur(void) -{ - mutex_lock(&doms_cur_mutex); -} - -static inline void unlock_doms_cur(void) -{ - mutex_unlock(&doms_cur_mutex); -} - -#else - -static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } -static inline void lock_doms_cur(void) { } -static inline void unlock_doms_cur(void) { } - -#endif /* CONFIG_GROUP_SCHED */ - -/* CFS-related fields in a runqueue */ -struct cfs_rq { - struct load_weight load; - unsigned long nr_running; - - u64 exec_clock; - u64 min_vruntime; - - struct rb_root tasks_timeline; - struct rb_node *rb_leftmost; - struct rb_node *rb_load_balance_curr; - /* 'curr' points to currently running entity on this cfs_rq. - * It is set to NULL otherwise (i.e when none are currently running). - */ - struct sched_entity *curr, *next; - - unsigned long nr_spread_over; - -#ifdef CONFIG_FAIR_GROUP_SCHED - struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ - - /* - * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in - * a hierarchy). Non-leaf lrqs hold other higher schedulable entities - * (like users, containers etc.) - * - * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This - * list is used during load balance. - */ - struct list_head leaf_cfs_rq_list; - struct task_group *tg; /* group that "owns" this runqueue */ -#endif -}; - -/* Real-Time classes' related field in a runqueue: */ -struct rt_rq { - struct rt_prio_array active; - unsigned long rt_nr_running; -#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED - int highest_prio; /* highest queued rt task prio */ -#endif -#ifdef CONFIG_SMP - unsigned long rt_nr_migratory; - int overloaded; -#endif - int rt_throttled; - u64 rt_time; - -#ifdef CONFIG_RT_GROUP_SCHED - unsigned long rt_nr_boosted; - - struct rq *rq; - struct list_head leaf_rt_rq_list; - struct task_group *tg; - struct sched_rt_entity *rt_se; -#endif -}; - -#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; - cpumask_t span; - cpumask_t online; - - /* - * The "RT overload" flag: it gets set if a CPU has more than - * one runnable RT task. - */ - cpumask_t rto_mask; - atomic_t rto_count; -}; - -/* - * 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 - -/* - * This is the main, per-CPU runqueue data structure. - * - * Locking rule: those places that want to lock multiple runqueues - * (such as the load balancing or the thread migration code), lock - * acquire operations must be ordered by ascending &runqueue. - */ -struct rq { - /* runqueue lock: */ - spinlock_t lock; - - /* - * nr_running and cpu_load should be in the same cacheline because - * remote CPUs use both these fields when doing load calculation. - */ - unsigned long nr_running; - #define CPU_LOAD_IDX_MAX 5 - unsigned long cpu_load[CPU_LOAD_IDX_MAX]; - unsigned char idle_at_tick; -#ifdef CONFIG_NO_HZ - unsigned char in_nohz_recently; -#endif - /* capture load from *all* tasks on this cpu: */ - struct load_weight load; - unsigned long nr_load_updates; - u64 nr_switches; - - struct cfs_rq cfs; - struct rt_rq rt; - u64 rt_period_expire; - int rt_throttled; - -#ifdef CONFIG_FAIR_GROUP_SCHED - /* list of leaf cfs_rq on this cpu: */ - struct list_head leaf_cfs_rq_list; -#endif -#ifdef CONFIG_RT_GROUP_SCHED - struct list_head leaf_rt_rq_list; -#endif - - /* - * This is part of a global counter where only the total sum - * over all CPUs matters. A task can increase this counter on - * one CPU and if it got migrated afterwards it may decrease - * it on another CPU. Always updated under the runqueue lock: - */ - unsigned long nr_uninterruptible; - - struct task_struct *curr, *idle; - unsigned long next_balance; - struct mm_struct *prev_mm; - - u64 clock, prev_clock_raw; - s64 clock_max_delta; - - unsigned int clock_warps, clock_overflows, clock_underflows; - u64 idle_clock; - unsigned int clock_deep_idle_events; - u64 tick_timestamp; - - atomic_t nr_iowait; - -#ifdef CONFIG_SMP - struct root_domain *rd; - struct sched_domain *sd; - - /* For active balancing */ - int active_balance; - int push_cpu; - /* cpu of this runqueue: */ - int cpu; - - struct task_struct *migration_thread; - struct list_head migration_queue; -#endif - -#ifdef CONFIG_SCHED_HRTICK - unsigned long hrtick_flags; - ktime_t hrtick_expire; - struct hrtimer hrtick_timer; -#endif - -#ifdef CONFIG_SCHEDSTATS - /* latency stats */ - struct sched_info rq_sched_info; - - /* sys_sched_yield() stats */ - unsigned int yld_exp_empty; - unsigned int yld_act_empty; - unsigned int yld_both_empty; - 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; - - /* BKL stats */ - unsigned int bkl_count; -#endif - struct lock_class_key rq_lock_key; -}; - -static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); - -static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) -{ - rq->curr->sched_class->check_preempt_curr(rq, p); -} - -static inline int cpu_of(struct rq *rq) -{ -#ifdef CONFIG_SMP - return rq->cpu; -#else - return 0; -#endif -} - -/* - * Update the per-runqueue clock, as finegrained as the platform can give - * us, but without assuming monotonicity, etc.: - */ -static void __update_rq_clock(struct rq *rq) -{ - u64 prev_raw = rq->prev_clock_raw; - u64 now = sched_clock(); - s64 delta = now - prev_raw; - u64 clock = rq->clock; - -#ifdef CONFIG_SCHED_DEBUG - WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); -#endif - /* - * Protect against sched_clock() occasionally going backwards: - */ - if (unlikely(delta < 0)) { - clock++; - rq->clock_warps++; - } else { - /* - * Catch too large forward jumps too: - */ - if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) { - if (clock < rq->tick_timestamp + TICK_NSEC) - clock = rq->tick_timestamp + TICK_NSEC; - else - clock++; - rq->clock_overflows++; - } else { - if (unlikely(delta > rq->clock_max_delta)) - rq->clock_max_delta = delta; - clock += delta; - } - } - - rq->prev_clock_raw = now; - rq->clock = clock; -} - -static void update_rq_clock(struct rq *rq) -{ - if (likely(smp_processor_id() == cpu_of(rq))) - __update_rq_clock(rq); -} - -/* - * 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(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) - -#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) - -unsigned long rt_needs_cpu(int cpu) -{ - struct rq *rq = cpu_rq(cpu); - u64 delta; - - if (!rq->rt_throttled) - return 0; - - if (rq->clock > rq->rt_period_expire) - return 1; - - delta = rq->rt_period_expire - rq->clock; - do_div(delta, NSEC_PER_SEC / HZ); - - return (unsigned long)delta; -} - -/* - * Tunables that become constants when CONFIG_SCHED_DEBUG is off: - */ -#ifdef CONFIG_SCHED_DEBUG -# define const_debug __read_mostly -#else -# define const_debug static const -#endif - -/* - * Debugging: various feature bits - */ -enum { - SCHED_FEAT_NEW_FAIR_SLEEPERS = 1, - SCHED_FEAT_WAKEUP_PREEMPT = 2, - SCHED_FEAT_START_DEBIT = 4, - SCHED_FEAT_HRTICK = 8, - SCHED_FEAT_DOUBLE_TICK = 16, -}; - -const_debug unsigned int sysctl_sched_features = - SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 | - SCHED_FEAT_WAKEUP_PREEMPT * 1 | - SCHED_FEAT_START_DEBIT * 1 | - SCHED_FEAT_HRTICK * 1 | - SCHED_FEAT_DOUBLE_TICK * 0; - -#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x) - -/* - * Number of tasks to iterate in a single balance run. - * Limited because this is done with IRQs disabled. - */ -const_debug unsigned int sysctl_sched_nr_migrate = 32; - -/* - * period over which we measure -rt task cpu usage in us. - * default: 1s - */ -unsigned int sysctl_sched_rt_period = 1000000; - -static __read_mostly int scheduler_running; - -/* - * part of the period that we allow rt tasks to run in us. - * default: 0.95s - */ -int sysctl_sched_rt_runtime = 950000; - -/* - * single value that denotes runtime == period, ie unlimited time. - */ -#define RUNTIME_INF ((u64)~0ULL) - -/* - * For kernel-internal use: high-speed (but slightly incorrect) per-cpu - * clock constructed from sched_clock(): - */ -unsigned long long cpu_clock(int cpu) -{ - unsigned long long now; - unsigned long flags; - struct rq *rq; - - /* - * Only call sched_clock() if the scheduler has already been - * initialized (some code might call cpu_clock() very early): - */ - if (unlikely(!scheduler_running)) - return 0; - - local_irq_save(flags); - rq = cpu_rq(cpu); - update_rq_clock(rq); - now = rq->clock; - local_irq_restore(flags); - - return now; -} -EXPORT_SYMBOL_GPL(cpu_clock); - -#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 - -static inline int task_current(struct rq *rq, struct task_struct *p) -{ - return rq->curr == p; -} - -#ifndef __ARCH_WANT_UNLOCKED_CTXSW -static inline int task_running(struct rq *rq, struct task_struct *p) -{ - return task_current(rq, p); -} - -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 */ - rq->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(&rq->lock.dep_map, 0, 0, _THIS_IP_); - - spin_unlock_irq(&rq->lock); -} - -#else /* __ARCH_WANT_UNLOCKED_CTXSW */ -static inline int task_running(struct rq *rq, struct task_struct *p) -{ -#ifdef CONFIG_SMP - return p->oncpu; -#else - return task_current(rq, p); -#endif -} - -static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) -{ -#ifdef CONFIG_SMP - /* - * We can optimise this out completely for !SMP, because the - * SMP rebalancing from interrupt is the only thing that cares - * here. - */ - next->oncpu = 1; -#endif -#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW - spin_unlock_irq(&rq->lock); -#else - spin_unlock(&rq->lock); -#endif -} - -static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) -{ -#ifdef CONFIG_SMP - /* - * After ->oncpu is cleared, the task can be moved to a different CPU. - * We must ensure this doesn't happen until the switch is completely - * finished. - */ - smp_wmb(); - prev->oncpu = 0; -#endif -#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW - local_irq_enable(); -#endif -} -#endif /* __ARCH_WANT_UNLOCKED_CTXSW */ - -/* - * __task_rq_lock - lock the runqueue a given task resides on. - * Must be called interrupts disabled. - */ -static inline struct rq *__task_rq_lock(struct task_struct *p) - __acquires(rq->lock) -{ - for (;;) { - struct rq *rq = task_rq(p); - spin_lock(&rq->lock); - if (likely(rq == task_rq(p))) - return rq; - spin_unlock(&rq->lock); - } -} - -/* - * task_rq_lock - lock the runqueue a given task resides on and disable - * interrupts. Note the ordering: we can safely lookup the task_rq without - * explicitly disabling preemption. - */ -static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) - __acquires(rq->lock) -{ - struct rq *rq; - - for (;;) { - local_irq_save(*flags); - rq = task_rq(p); - spin_lock(&rq->lock); - if (likely(rq == task_rq(p))) - return rq; - spin_unlock_irqrestore(&rq->lock, *flags); - } -} - -static void __task_rq_unlock(struct rq *rq) - __releases(rq->lock) -{ - spin_unlock(&rq->lock); -} - -static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) - __releases(rq->lock) -{ - spin_unlock_irqrestore(&rq->lock, *flags); -} - -/* - * this_rq_lock - lock this runqueue and disable interrupts. - */ -static struct rq *this_rq_lock(void) - __acquires(rq->lock) -{ - struct rq *rq; - - local_irq_disable(); - rq = this_rq(); - spin_lock(&rq->lock); - - return rq; -} - -/* - * We are going deep-idle (irqs are disabled): - */ -void sched_clock_idle_sleep_event(void) -{ - struct rq *rq = cpu_rq(smp_processor_id()); - - spin_lock(&rq->lock); - __update_rq_clock(rq); - spin_unlock(&rq->lock); - rq->clock_deep_idle_events++; -} -EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event); - -/* - * We just idled delta nanoseconds (called with irqs disabled): - */ -void sched_clock_idle_wakeup_event(u64 delta_ns) -{ - struct rq *rq = cpu_rq(smp_processor_id()); - u64 now = sched_clock(); - - rq->idle_clock += delta_ns; - /* - * Override the previous timestamp and ignore all - * sched_clock() deltas that occured while we idled, - * and use the PM-provided delta_ns to advance the - * rq clock: - */ - spin_lock(&rq->lock); - rq->prev_clock_raw = now; - rq->clock += delta_ns; - spin_unlock(&rq->lock); - touch_softlockup_watchdog(); -} -EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event); - -static void __resched_task(struct task_struct *p, int tif_bit); - -static inline void resched_task(struct task_struct *p) -{ - __resched_task(p, TIF_NEED_RESCHED); -} - -#ifdef CONFIG_SCHED_HRTICK -/* - * Use HR-timers to deliver accurate preemption points. - * - * Its all a bit involved since we cannot program an hrt while holding the - * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a - * reschedule event. - * - * When we get rescheduled we reprogram the hrtick_timer outside of the - * rq->lock. - */ -static inline void resched_hrt(struct task_struct *p) -{ - __resched_task(p, TIF_HRTICK_RESCHED); -} - -static inline void resched_rq(struct rq *rq) -{ - unsigned long flags; - - spin_lock_irqsave(&rq->lock, flags); - resched_task(rq->curr); - spin_unlock_irqrestore(&rq->lock, flags); -} - -enum { - HRTICK_SET, /* re-programm hrtick_timer */ - HRTICK_RESET, /* not a new slice */ -}; - -/* - * Use hrtick when: - * - enabled by features - * - hrtimer is actually high res - */ -static inline int hrtick_enabled(struct rq *rq) -{ - if (!sched_feat(HRTICK)) - return 0; - return hrtimer_is_hres_active(&rq->hrtick_timer); -} - -/* - * Called to set the hrtick timer state. - * - * called with rq->lock held and irqs disabled - */ -static void hrtick_start(struct rq *rq, u64 delay, int reset) -{ - assert_spin_locked(&rq->lock); - - /* - * preempt at: now + delay - */ - rq->hrtick_expire = - ktime_add_ns(rq->hrtick_timer.base->get_time(), delay); - /* - * indicate we need to program the timer - */ - __set_bit(HRTICK_SET, &rq->hrtick_flags); - if (reset) - __set_bit(HRTICK_RESET, &rq->hrtick_flags); - - /* - * New slices are called from the schedule path and don't need a - * forced reschedule. - */ - if (reset) - resched_hrt(rq->curr); -} - -static void hrtick_clear(struct rq *rq) -{ - if (hrtimer_active(&rq->hrtick_timer)) - hrtimer_cancel(&rq->hrtick_timer); -} - -/* - * Update the timer from the possible pending state. - */ -static void hrtick_set(struct rq *rq) -{ - ktime_t time; - int set, reset; - unsigned long flags; - - WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); - - spin_lock_irqsave(&rq->lock, flags); - set = __test_and_clear_bit(HRTICK_SET, &rq->hrtick_flags); - reset = __test_and_clear_bit(HRTICK_RESET, &rq->hrtick_flags); - time = rq->hrtick_expire; - clear_thread_flag(TIF_HRTICK_RESCHED); - spin_unlock_irqrestore(&rq->lock, flags); - - if (set) { - hrtimer_start(&rq->hrtick_timer, time, HRTIMER_MODE_ABS); - if (reset && !hrtimer_active(&rq->hrtick_timer)) - resched_rq(rq); - } else - hrtick_clear(rq); -} - -/* - * High-resolution timer tick. - * Runs from hardirq context with interrupts disabled. - */ -static enum hrtimer_restart hrtick(struct hrtimer *timer) -{ - struct rq *rq = container_of(timer, struct rq, hrtick_timer); - - WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); - - spin_lock(&rq->lock); - __update_rq_clock(rq); - rq->curr->sched_class->task_tick(rq, rq->curr, 1); - spin_unlock(&rq->lock); - - return HRTIMER_NORESTART; -} - -static inline void init_rq_hrtick(struct rq *rq) -{ - rq->hrtick_flags = 0; - hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); - rq->hrtick_timer.function = hrtick; - rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; -} - -void hrtick_resched(void) -{ - struct rq *rq; - unsigned long flags; - - if (!test_thread_flag(TIF_HRTICK_RESCHED)) - return; - - local_irq_save(flags); - rq = cpu_rq(smp_processor_id()); - hrtick_set(rq); - local_irq_restore(flags); -} -#else -static inline void hrtick_clear(struct rq *rq) -{ -} - -static inline void hrtick_set(struct rq *rq) -{ -} - -static inline void init_rq_hrtick(struct rq *rq) -{ -} - -void hrtick_resched(void) -{ -} -#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 tif_bit) -{ - int cpu; - - assert_spin_locked(&task_rq(p)->lock); - - if (unlikely(test_tsk_thread_flag(p, tif_bit))) - return; - - set_tsk_thread_flag(p, tif_bit); - - 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); -} - -static void resched_cpu(int cpu) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long flags; - - if (!spin_trylock_irqsave(&rq->lock, flags)) - return; - resched_task(cpu_curr(cpu)); - spin_unlock_irqrestore(&rq->lock, flags); -} - -#ifdef CONFIG_NO_HZ -/* - * 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 rq *rq = cpu_rq(cpu); - - if (cpu == smp_processor_id()) - return; - - /* - * 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 serialized on the timer wheel base lock and take the new - * timer into account automatically. - */ - if (rq->curr != rq->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_thread_flag(rq->idle, TIF_NEED_RESCHED); - - /* NEED_RESCHED must be visible before we test polling */ - smp_mb(); - if (!tsk_is_polling(rq->idle)) - smp_send_reschedule(cpu); -} -#endif - -#else -static void __resched_task(struct task_struct *p, int tif_bit) -{ - assert_spin_locked(&task_rq(p)->lock); - set_tsk_thread_flag(p, tif_bit); -} -#endif - -#if BITS_PER_LONG == 32 -# define WMULT_CONST (~0UL) -#else -# define WMULT_CONST (1UL << 32) -#endif - -#define WMULT_SHIFT 32 - -/* - * Shift right and round: - */ -#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) - -static unsigned long -calc_delta_mine(unsigned long delta_exec, unsigned long weight, - struct load_weight *lw) -{ - u64 tmp; - - if (unlikely(!lw->inv_weight)) - lw->inv_weight = (WMULT_CONST-lw->weight/2) / (lw->weight+1); - - tmp = (u64)delta_exec * weight; - /* - * Check whether we'd overflow the 64-bit multiplication: - */ - if (unlikely(tmp > WMULT_CONST)) - tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, - WMULT_SHIFT/2); - else - tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); - - return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); -} - -static inline unsigned long -calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) -{ - return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); -} - -static inline void update_load_add(struct load_weight *lw, unsigned long inc) -{ - lw->weight += inc; - lw->inv_weight = 0; -} - -static inline void update_load_sub(struct load_weight *lw, unsigned long dec) -{ - lw->weight -= dec; - lw->inv_weight = 0; -} - -/* - * To aid in avoiding the subversion of "niceness" due to uneven distribution - * of tasks with abnormal "nice" values across CPUs the contribution that - * each task makes to its run queue's load is weighted according to its - * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a - * scaled version of the new time slice allocation that they receive on time - * slice expiry etc. - */ - -#define WEIGHT_IDLEPRIO 2 -#define WMULT_IDLEPRIO (1 << 31) - -/* - * Nice levels are multiplicative, with a gentle 10% change for every - * nice level changed. I.e. when a CPU-bound task goes from nice 0 to - * nice 1, it will get ~10% less CPU time than another CPU-bound task - * that remained on nice 0. - * - * The "10% effect" is relative and cumulative: from _any_ nice level, - * if you go up 1 level, it's -10% CPU usage, if you go down 1 level - * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. - * If a task goes up by ~10% and another task goes down by ~10% then - * the relative distance between them is ~25%.) - */ -static const int prio_to_weight[40] = { - /* -20 */ 88761, 71755, 56483, 46273, 36291, - /* -15 */ 29154, 23254, 18705, 14949, 11916, - /* -10 */ 9548, 7620, 6100, 4904, 3906, - /* -5 */ 3121, 2501, 1991, 1586, 1277, - /* 0 */ 1024, 820, 655, 526, 423, - /* 5 */ 335, 272, 215, 172, 137, - /* 10 */ 110, 87, 70, 56, 45, - /* 15 */ 36, 29, 23, 18, 15, -}; - -/* - * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. - * - * In cases where the weight does not change often, we can use the - * precalculated inverse to speed up arithmetics by turning divisions - * into multiplications: - */ -static const u32 prio_to_wmult[40] = { - /* -20 */ 48388, 59856, 76040, 92818, 118348, - /* -15 */ 147320, 184698, 229616, 287308, 360437, - /* -10 */ 449829, 563644, 704093, 875809, 1099582, - /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, - /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, - /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, - /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, - /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, -}; - -static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); - -/* - * runqueue iterator, to support SMP load-balancing between different - * scheduling classes, without having to expose their internal data - * structures to the load-balancing proper: - */ -struct rq_iterator { - void *arg; - struct task_struct *(*start)(void *); - struct task_struct *(*next)(void *); -}; - -#ifdef CONFIG_SMP -static unsigned long -balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, struct sched_domain *sd, - enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct rq_iterator *iterator); - -static int -iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle, - struct rq_iterator *iterator); -#endif - -#ifdef CONFIG_CGROUP_CPUACCT -static void cpuacct_charge(struct task_struct *tsk, u64 cputime); -#else -static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} -#endif - -#ifdef CONFIG_SMP -static unsigned long source_load(int cpu, int type); -static unsigned long target_load(int cpu, int type); -static unsigned long cpu_avg_load_per_task(int cpu); -static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); -#endif /* CONFIG_SMP */ - -#include "sched_stats.h" -#include "sched_idletask.c" -#include "sched_fair.c" -#include "sched_rt.c" -#ifdef CONFIG_SCHED_DEBUG -# include "sched_debug.c" -#endif - -#define sched_class_highest (&rt_sched_class) - -static inline void inc_load(struct rq *rq, const struct task_struct *p) -{ - update_load_add(&rq->load, p->se.load.weight); -} - -static inline void dec_load(struct rq *rq, const struct task_struct *p) -{ - update_load_sub(&rq->load, p->se.load.weight); -} - -static void inc_nr_running(struct task_struct *p, struct rq *rq) -{ - rq->nr_running++; - inc_load(rq, p); -} - -static void dec_nr_running(struct task_struct *p, struct rq *rq) -{ - rq->nr_running--; - dec_load(rq, p); -} - -static void set_load_weight(struct task_struct *p) -{ - if (task_has_rt_policy(p)) { - p->se.load.weight = prio_to_weight[0] * 2; - p->se.load.inv_weight = prio_to_wmult[0] >> 1; - return; - } - - /* - * SCHED_IDLE tasks get minimal weight: - */ - if (p->policy == SCHED_IDLE) { - p->se.load.weight = WEIGHT_IDLEPRIO; - p->se.load.inv_weight = WMULT_IDLEPRIO; - return; - } - - p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; - p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; -} - -static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) -{ - sched_info_queued(p); - p->sched_class->enqueue_task(rq, p, wakeup); - p->se.on_rq = 1; -} - -static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) -{ - p->sched_class->dequeue_task(rq, p, sleep); - p->se.on_rq = 0; -} - -/* - * __normal_prio - return the priority that is based on the static prio - */ -static inline int __normal_prio(struct task_struct *p) -{ - return p->static_prio; -} - -/* - * Calculate the expected normal priority: i.e. priority - * without taking RT-inheritance into account. Might be - * boosted by interactivity modifiers. Changes upon fork, - * setprio syscalls, and whenever the interactivity - * estimator recalculates. - */ -static inline int normal_prio(struct task_struct *p) -{ - int prio; - - if (task_has_rt_policy(p)) - prio = MAX_RT_PRIO-1 - p->rt_priority; - else - prio = __normal_prio(p); - return prio; -} - -/* - * Calculate the current priority, i.e. the priority - * taken into account by the scheduler. This value might - * be boosted by RT tasks, or might be boosted by - * interactivity modifiers. Will be RT if the task got - * RT-boosted. If not then it returns p->normal_prio. - */ -static int effective_prio(struct task_struct *p) -{ - p->normal_prio = normal_prio(p); - /* - * If we are RT tasks or we were boosted to RT priority, - * keep the priority unchanged. Otherwise, update priority - * to the normal priority: - */ - if (!rt_prio(p->prio)) - return p->normal_prio; - return p->prio; -} - -/* - * activate_task - move a task to the runqueue. - */ -static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) -{ - if (task_contributes_to_load(p)) - rq->nr_uninterruptible--; - - enqueue_task(rq, p, wakeup); - inc_nr_running(p, rq); -} - -/* - * deactivate_task - remove a task from the runqueue. - */ -static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) -{ - if (task_contributes_to_load(p)) - rq->nr_uninterruptible++; - - dequeue_task(rq, p, sleep); - dec_nr_running(p, rq); -} - -/** - * 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; -} - -/* Used instead of source_load when we know the type == 0 */ -unsigned long weighted_cpuload(const int cpu) -{ - return cpu_rq(cpu)->load.weight; -} - -static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) -{ - set_task_rq(p, cpu); -#ifdef CONFIG_SMP - /* - * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be - * successfuly 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; -#endif -} - -static inline void check_class_changed(struct rq *rq, struct task_struct *p, - const struct sched_class *prev_class, - int oldprio, int running) -{ - if (prev_class != p->sched_class) { - if (prev_class->switched_from) - prev_class->switched_from(rq, p, running); - p->sched_class->switched_to(rq, p, running); - } else - p->sched_class->prio_changed(rq, p, oldprio, running); -} - -#ifdef CONFIG_SMP - -/* - * Is this task likely cache-hot: - */ -static int -task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) -{ - s64 delta; - - /* - * Buddy candidates are cache hot: - */ - if (&p->se == cfs_rq_of(&p->se)->next) - return 1; - - if (p->sched_class != &fair_sched_class) - return 0; - - if (sysctl_sched_migration_cost == -1) - return 1; - if (sysctl_sched_migration_cost == 0) - return 0; - - delta = now - p->se.exec_start; - - return delta < (s64)sysctl_sched_migration_cost; -} - - -void set_task_cpu(struct task_struct *p, unsigned int new_cpu) -{ - int old_cpu = task_cpu(p); - struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); - struct cfs_rq *old_cfsrq = task_cfs_rq(p), - *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); - u64 clock_offset; - - clock_offset = old_rq->clock - new_rq->clock; - -#ifdef CONFIG_SCHEDSTATS - if (p->se.wait_start) - p->se.wait_start -= clock_offset; - if (p->se.sleep_start) - p->se.sleep_start -= clock_offset; - if (p->se.block_start) - p->se.block_start -= clock_offset; - if (old_cpu != new_cpu) { - schedstat_inc(p, se.nr_migrations); - if (task_hot(p, old_rq->clock, NULL)) - schedstat_inc(p, se.nr_forced2_migrations); - } -#endif - p->se.vruntime -= old_cfsrq->min_vruntime - - new_cfsrq->min_vruntime; - - __set_task_cpu(p, new_cpu); -} - -struct migration_req { - struct list_head list; - - struct task_struct *task; - int dest_cpu; - - struct completion done; -}; - -/* - * The task's runqueue lock must be held. - * Returns true if you have to wait for migration thread. - */ -static int -migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) -{ - struct rq *rq = task_rq(p); - - /* - * If the task is not on a runqueue (and not running), then - * it is sufficient to simply update the task's cpu field. - */ - if (!p->se.on_rq && !task_running(rq, p)) { - set_task_cpu(p, dest_cpu); - return 0; - } - - init_completion(&req->done); - req->task = p; - req->dest_cpu = dest_cpu; - list_add(&req->list, &rq->migration_queue); - - return 1; -} - -/* - * wait_task_inactive - wait for a thread to unschedule. - * - * 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. - */ -void wait_task_inactive(struct task_struct *p) -{ - unsigned long flags; - int running, on_rq; - 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! - */ - rq = task_rq(p); - - /* - * If the task is actively running on another CPU - * still, just relax and busy-wait without holding - * any locks. - * - * NOTE! Since we don't hold any locks, it's not - * even sure that "rq" stays as the right runqueue! - * But we don't care, since "task_running()" will - * return false if the runqueue has changed and p - * is actually now running somewhere else! - */ - while (task_running(rq, p)) - cpu_relax(); - - /* - * Ok, time to look more closely! We need the rq - * lock now, to be *sure*. If we're wrong, we'll - * just go back and repeat. - */ - rq = task_rq_lock(p, &flags); - running = task_running(rq, p); - on_rq = p->se.on_rq; - task_rq_unlock(rq, &flags); - - /* - * 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 wa 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)) { - schedule_timeout_uninterruptible(1); - 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; - } -} - -/*** - * 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 doesnt 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(); -} - -/* - * Return a low guess at the load of a migration-source cpu weighted - * according to the scheduling class and "nice" value. - * - * We want to under-estimate the load of migration sources, to - * balance conservatively. - */ -static unsigned long source_load(int cpu, int type) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long total = weighted_cpuload(cpu); - - if (type == 0) - return total; - - return min(rq->cpu_load[type-1], total); -} - -/* - * Return a high guess at the load of a migration-target cpu weighted - * according to the scheduling class and "nice" value. - */ -static unsigned long target_load(int cpu, int type) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long total = weighted_cpuload(cpu); - - if (type == 0) - return total; - - return max(rq->cpu_load[type-1], total); -} - -/* - * Return the average load per task on the cpu's run queue - */ -static unsigned long cpu_avg_load_per_task(int cpu) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long total = weighted_cpuload(cpu); - unsigned long n = rq->nr_running; - - return n ? total / n : SCHED_LOAD_SCALE; -} - -/* - * find_idlest_group finds and returns the least busy CPU group within the - * domain. - */ -static struct sched_group * -find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) -{ - struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; - unsigned long min_load = ULONG_MAX, this_load = 0; - int load_idx = sd->forkexec_idx; - int imbalance = 100 + (sd->imbalance_pct-100)/2; - - do { - unsigned long load, avg_load; - int local_group; - int i; - - /* Skip over this group if it has no CPUs allowed */ - if (!cpus_intersects(group->cpumask, p->cpus_allowed)) - continue; - - local_group = cpu_isset(this_cpu, group->cpumask); - - /* Tally up the load of all CPUs in the group */ - avg_load = 0; - - for_each_cpu_mask(i, group->cpumask) { - /* Bias balancing toward cpus of our domain */ - if (local_group) - load = source_load(i, load_idx); - else - load = target_load(i, load_idx); - - avg_load += load; - } - - /* Adjust by relative CPU power of the group */ - avg_load = sg_div_cpu_power(group, - avg_load * SCHED_LOAD_SCALE); - - if (local_group) { - this_load = avg_load; - this = group; - } else if (avg_load < min_load) { - min_load = avg_load; - idlest = group; - } - } while (group = group->next, group != sd->groups); - - if (!idlest || 100*this_load < imbalance*min_load) - return NULL; - return idlest; -} - -/* - * find_idlest_cpu - find the idlest cpu among the cpus in group. - */ -static int -find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) -{ - cpumask_t tmp; - unsigned long load, min_load = ULONG_MAX; - int idlest = -1; - int i; - - /* Traverse only the allowed CPUs */ - cpus_and(tmp, group->cpumask, p->cpus_allowed); - - for_each_cpu_mask(i, tmp) { - load = weighted_cpuload(i); - - if (load < min_load || (load == min_load && i == this_cpu)) { - min_load = load; - idlest = i; - } - } - - return idlest; -} - -/* - * sched_balance_self: balance the current task (running on cpu) in domains - * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and - * SD_BALANCE_EXEC. - * - * Balance, ie. select the least loaded group. - * - * Returns the target CPU number, or the same CPU if no balancing is needed. - * - * preempt must be disabled. - */ -static int sched_balance_self(int cpu, int flag) -{ - struct task_struct *t = current; - struct sched_domain *tmp, *sd = NULL; - - for_each_domain(cpu, tmp) { - /* - * If power savings logic is enabled for a domain, stop there. - */ - if (tmp->flags & SD_POWERSAVINGS_BALANCE) - break; - if (tmp->flags & flag) - sd = tmp; - } - - while (sd) { - cpumask_t span; - struct sched_group *group; - int new_cpu, weight; - - if (!(sd->flags & flag)) { - sd = sd->child; - continue; - } - - span = sd->span; - group = find_idlest_group(sd, t, cpu); - if (!group) { - sd = sd->child; - continue; - } - - new_cpu = find_idlest_cpu(group, t, cpu); - if (new_cpu == -1 || new_cpu == cpu) { - /* Now try balancing at a lower domain level of cpu */ - sd = sd->child; - continue; - } - - /* Now try balancing at a lower domain level of new_cpu */ - cpu = new_cpu; - sd = NULL; - weight = cpus_weight(span); - for_each_domain(cpu, tmp) { - if (weight <= cpus_weight(tmp->span)) - break; - if (tmp->flags & flag) - sd = tmp; - } - /* while loop will break here if sd == NULL */ - } - - return cpu; -} - -#endif /* CONFIG_SMP */ - -/*** - * try_to_wake_up - wake up a thread - * @p: the to-be-woken-up thread - * @state: the mask of task states that can be woken - * @sync: do a synchronous wakeup? - * - * 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 failure only if the task is already active. - */ -static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) -{ - int cpu, orig_cpu, this_cpu, success = 0; - unsigned long flags; - long old_state; - struct rq *rq; - - smp_wmb(); - rq = task_rq_lock(p, &flags); - old_state = p->state; - if (!(old_state & state)) - goto out; - - if (p->se.on_rq) - goto out_running; - - cpu = task_cpu(p); - orig_cpu = cpu; - this_cpu = smp_processor_id(); - -#ifdef CONFIG_SMP - if (unlikely(task_running(rq, p))) - goto out_activate; - - cpu = p->sched_class->select_task_rq(p, sync); - if (cpu != orig_cpu) { - set_task_cpu(p, cpu); - task_rq_unlock(rq, &flags); - /* might preempt at this point */ - rq = task_rq_lock(p, &flags); - old_state = p->state; - if (!(old_state & state)) - goto out; - if (p->se.on_rq) - goto out_running; - - this_cpu = smp_processor_id(); - cpu = task_cpu(p); - } - -#ifdef CONFIG_SCHEDSTATS - schedstat_inc(rq, ttwu_count); - if (cpu == this_cpu) - schedstat_inc(rq, ttwu_local); - else { - struct sched_domain *sd; - for_each_domain(this_cpu, sd) { - if (cpu_isset(cpu, sd->span)) { - schedstat_inc(sd, ttwu_wake_remote); - break; - } - } - } -#endif - -out_activate: -#endif /* CONFIG_SMP */ - schedstat_inc(p, se.nr_wakeups); - if (sync) - schedstat_inc(p, se.nr_wakeups_sync); - if (orig_cpu != cpu) - schedstat_inc(p, se.nr_wakeups_migrate); - if (cpu == this_cpu) - schedstat_inc(p, se.nr_wakeups_local); - else - schedstat_inc(p, se.nr_wakeups_remote); - update_rq_clock(rq); - activate_task(rq, p, 1); - success = 1; - -out_running: - check_preempt_curr(rq, p); - - p->state = TASK_RUNNING; -#ifdef CONFIG_SMP - if (p->sched_class->task_wake_up) - p->sched_class->task_wake_up(rq, p); -#endif -out: - task_rq_unlock(rq, &flags); - - return success; -} - -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); -} - -/* - * Perform scheduler related setup for a newly forked process p. - * p is forked by current. - * - * __sched_fork() is basic setup used by init_idle() too: - */ -static void __sched_fork(struct task_struct *p) -{ - p->se.exec_start = 0; - p->se.sum_exec_runtime = 0; - p->se.prev_sum_exec_runtime = 0; - p->se.last_wakeup = 0; - p->se.avg_overlap = 0; - -#ifdef CONFIG_SCHEDSTATS - p->se.wait_start = 0; - p->se.sum_sleep_runtime = 0; - p->se.sleep_start = 0; - p->se.block_start = 0; - p->se.sleep_max = 0; - p->se.block_max = 0; - p->se.exec_max = 0; - p->se.slice_max = 0; - p->se.wait_max = 0; -#endif - - INIT_LIST_HEAD(&p->rt.run_list); - p->se.on_rq = 0; - -#ifdef CONFIG_PREEMPT_NOTIFIERS - INIT_HLIST_HEAD(&p->preempt_notifiers); -#endif - - /* - * We mark the process as running here, but have not actually - * inserted it onto the runqueue yet. 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; -} - -/* - * fork()/clone()-time setup: - */ -void sched_fork(struct task_struct *p, int clone_flags) -{ - int cpu = get_cpu(); - - __sched_fork(p); - -#ifdef CONFIG_SMP - cpu = sched_balance_self(cpu, SD_BALANCE_FORK); -#endif - set_task_cpu(p, cpu); - - /* - * Make sure we do not leak PI boosting priority to the child: - */ - p->prio = current->normal_prio; - if (!rt_prio(p->prio)) - p->sched_class = &fair_sched_class; - -#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) - if (likely(sched_info_on())) - memset(&p->sched_info, 0, sizeof(p->sched_info)); -#endif -#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) - p->oncpu = 0; -#endif -#ifdef CONFIG_PREEMPT - /* Want to start with kernel preemption disabled. */ - task_thread_info(p)->preempt_count = 1; -#endif - 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, unsigned long clone_flags) -{ - unsigned long flags; - struct rq *rq; - - rq = task_rq_lock(p, &flags); - BUG_ON(p->state != TASK_RUNNING); - update_rq_clock(rq); - - p->prio = effective_prio(p); - - if (!p->sched_class->task_new || !current->se.on_rq) { - activate_task(rq, p, 0); - } else { - /* - * Let the scheduling class do new task startup - * management (if any): - */ - p->sched_class->task_new(rq, p); - inc_nr_running(p, rq); - } - check_preempt_curr(rq, p); -#ifdef CONFIG_SMP - if (p->sched_class->task_wake_up) - p->sched_class->task_wake_up(rq, p); -#endif - task_rq_unlock(rq, &flags); -} - -#ifdef CONFIG_PREEMPT_NOTIFIERS - -/** - * preempt_notifier_register - tell me when current is being 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 - -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 - -/** - * prepare_task_switch - prepare to switch tasks - * @rq: the runqueue preparing to switch - * @prev: the current task that is being switched out - * @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) -{ - fire_sched_out_preempt_notifiers(prev, next); - prepare_lock_switch(rq, next); - prepare_arch_switch(next); -} - -/** - * finish_task_switch - clean up after a task-switch - * @rq: runqueue associated with task-switch - * @prev: the thread we just switched away from. - * - * finish_task_switch must be called after the context switch, paired - * with a prepare_task_switch call before the context switch. - * finish_task_switch will reconcile locking set up by prepare_task_switch, - * and do any other architecture-specific cleanup actions. - * - * Note that we may have delayed dropping an mm in context_switch(). If - * so, we finish that here outside of the runqueue lock. (Doing it - * with the lock held can cause deadlocks; see schedule() for - * details.) - */ -static void finish_task_switch(struct rq *rq, struct task_struct *prev) - __releases(rq->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); - finish_lock_switch(rq, prev); -#ifdef CONFIG_SMP - if (current->sched_class->post_schedule) - current->sched_class->post_schedule(rq); -#endif - - 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(rq->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(task_pid_vnr(current), 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_enter_lazy_cpu_mode(); - - if (unlikely(!mm)) { - next->active_mm = oldmm; - atomic_inc(&oldmm->mm_count); - enter_lazy_tlb(oldmm, next); - } else - switch_mm(oldmm, mm, next); - - if (unlikely(!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(&rq->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. - */ -unsigned long nr_running(void) -{ - unsigned long i, sum = 0; - - for_each_online_cpu(i) - sum += cpu_rq(i)->nr_running; - - return sum; -} - -unsigned long nr_uninterruptible(void) -{ - unsigned long i, sum = 0; - - for_each_possible_cpu(i) - sum += cpu_rq(i)->nr_uninterruptible; - - /* - * Since we read the counters lockless, it might be slightly - * inaccurate. Do not allow it to go below zero though: - */ - if (unlikely((long)sum < 0)) - sum = 0; - - return sum; -} - -unsigned long long nr_context_switches(void) -{ - int i; - unsigned long long sum = 0; - - for_each_possible_cpu(i) - sum += cpu_rq(i)->nr_switches; - - return sum; -} - -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_active(void) -{ - unsigned long i, running = 0, uninterruptible = 0; - - for_each_online_cpu(i) { - running += cpu_rq(i)->nr_running; - uninterruptible += cpu_rq(i)->nr_uninterruptible; - } - - if (unlikely((long)uninterruptible < 0)) - uninterruptible = 0; - - return running + uninterruptible; -} - -/* - * Update rq->cpu_load[] statistics. This function is usually called every - * scheduler tick (TICK_NSEC). - */ -static void update_cpu_load(struct rq *this_rq) -{ - unsigned long this_load = this_rq->load.weight; - int i, scale; - - this_rq->nr_load_updates++; - - /* Update our load: */ - for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { - unsigned long old_load, new_load; - - /* scale is effectively 1 << i now, and >> i divides by scale */ - - old_load = this_rq->cpu_load[i]; - new_load = this_load; - /* - * Round up the averaging division if load is increasing. This - * prevents us from getting stuck on 9 if the load is 10, for - * example. - */ - if (new_load > old_load) - new_load += scale-1; - this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; - } -} - -#ifdef CONFIG_SMP - -/* - * double_rq_lock - safely lock two runqueues - * - * Note this does not disable interrupts like task_rq_lock, - * you need to do so manually before calling. - */ -static void double_rq_lock(struct rq *rq1, struct rq *rq2) - __acquires(rq1->lock) - __acquires(rq2->lock) -{ - BUG_ON(!irqs_disabled()); - if (rq1 == rq2) { - spin_lock(&rq1->lock); - __acquire(rq2->lock); /* Fake it out ;) */ - } else { - if (rq1 < rq2) { - spin_lock(&rq1->lock); - spin_lock(&rq2->lock); - } else { - spin_lock(&rq2->lock); - spin_lock(&rq1->lock); - } - } - update_rq_clock(rq1); - update_rq_clock(rq2); -} - -/* - * double_rq_unlock - safely unlock two runqueues - * - * Note this does not restore interrupts like task_rq_unlock, - * you need to do so manually after calling. - */ -static void double_rq_unlock(struct rq *rq1, struct rq *rq2) - __releases(rq1->lock) - __releases(rq2->lock) -{ - spin_unlock(&rq1->lock); - if (rq1 != rq2) - spin_unlock(&rq2->lock); - else - __release(rq2->lock); -} - -/* - * double_lock_balance - lock the busiest runqueue, this_rq is locked already. - */ -static int double_lock_balance(struct rq *this_rq, struct rq *busiest) - __releases(this_rq->lock) - __acquires(busiest->lock) - __acquires(this_rq->lock) -{ - int ret = 0; - - if (unlikely(!irqs_disabled())) { - /* printk() doesn't work good under rq->lock */ - spin_unlock(&this_rq->lock); - BUG_ON(1); - } - if (unlikely(!spin_trylock(&busiest->lock))) { - if (busiest < this_rq) { - spin_unlock(&this_rq->lock); - spin_lock(&busiest->lock); - spin_lock(&this_rq->lock); - ret = 1; - } else - spin_lock(&busiest->lock); - } - return ret; -} - -/* - * If dest_cpu is allowed for this process, migrate the task to it. - * This is accomplished by forcing the cpu_allowed mask to only - * allow dest_cpu, which will force the cpu onto dest_cpu. Then - * the cpu_allowed mask is restored. - */ -static void sched_migrate_task(struct task_struct *p, int dest_cpu) -{ - struct migration_req req; - unsigned long flags; - struct rq *rq; - - rq = task_rq_lock(p, &flags); - if (!cpu_isset(dest_cpu, p->cpus_allowed) - || unlikely(cpu_is_offline(dest_cpu))) - goto out; - - /* force the process onto the specified CPU */ - if (migrate_task(p, dest_cpu, &req)) { - /* Need to wait for migration thread (might exit: take ref). */ - struct task_struct *mt = rq->migration_thread; - - get_task_struct(mt); - task_rq_unlock(rq, &flags); - wake_up_process(mt); - put_task_struct(mt); - wait_for_completion(&req.done); - - return; - } -out: - task_rq_unlock(rq, &flags); -} - -/* - * sched_exec - execve() is a valuable balancing opportunity, because at - * this point the task has the smallest effective memory and cache footprint. - */ -void sched_exec(void) -{ - int new_cpu, this_cpu = get_cpu(); - new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); - put_cpu(); - if (new_cpu != this_cpu) - sched_migrate_task(current, new_cpu); -} - -/* - * pull_task - move a task from a remote runqueue to the local runqueue. - * Both runqueues must be locked. - */ -static void pull_task(struct rq *src_rq, struct task_struct *p, - struct rq *this_rq, int this_cpu) -{ - deactivate_task(src_rq, p, 0); - set_task_cpu(p, this_cpu); - activate_task(this_rq, p, 0); - /* - * Note that idle threads have a prio of MAX_PRIO, for this test - * to be always true for them. - */ - check_preempt_curr(this_rq, p); -} - -/* - * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? - */ -static -int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned) -{ - /* - * We do not migrate tasks that are: - * 1) running (obviously), or - * 2) cannot be migrated to this CPU due to cpus_allowed, or - * 3) are cache-hot on their current CPU. - */ - if (!cpu_isset(this_cpu, p->cpus_allowed)) { - schedstat_inc(p, se.nr_failed_migrations_affine); - return 0; - } - *all_pinned = 0; - - if (task_running(rq, p)) { - schedstat_inc(p, se.nr_failed_migrations_running); - return 0; - } - - /* - * Aggressive migration if: - * 1) task is cache cold, or - * 2) too many balance attempts have failed. - */ - - if (!task_hot(p, rq->clock, sd) || - sd->nr_balance_failed > sd->cache_nice_tries) { -#ifdef CONFIG_SCHEDSTATS - if (task_hot(p, rq->clock, sd)) { - schedstat_inc(sd, lb_hot_gained[idle]); - schedstat_inc(p, se.nr_forced_migrations); - } -#endif - return 1; - } - - if (task_hot(p, rq->clock, sd)) { - schedstat_inc(p, se.nr_failed_migrations_hot); - return 0; - } - return 1; -} - -static unsigned long -balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, struct sched_domain *sd, - enum cpu_idle_type idle, int *all_pinned, - int *this_best_prio, struct rq_iterator *iterator) -{ - int loops = 0, pulled = 0, pinned = 0, skip_for_load; - struct task_struct *p; - long rem_load_move = max_load_move; - - if (max_load_move == 0) - goto out; - - pinned = 1; - - /* - * Start the load-balancing iterator: - */ - p = iterator->start(iterator->arg); -next: - if (!p || loops++ > sysctl_sched_nr_migrate) - goto out; - /* - * To help distribute high priority tasks across CPUs we don't - * skip a task if it will be the highest priority task (i.e. smallest - * prio value) on its new queue regardless of its load weight - */ - skip_for_load = (p->se.load.weight >> 1) > rem_load_move + - SCHED_LOAD_SCALE_FUZZ; - if ((skip_for_load && p->prio >= *this_best_prio) || - !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { - p = iterator->next(iterator->arg); - goto next; - } - - pull_task(busiest, p, this_rq, this_cpu); - pulled++; - rem_load_move -= p->se.load.weight; - - /* - * We only want to steal up to the prescribed amount of weighted load. - */ - if (rem_load_move > 0) { - if (p->prio < *this_best_prio) - *this_best_prio = p->prio; - p = iterator->next(iterator->arg); - goto next; - } -out: - /* - * Right now, this is one of only two places pull_task() is called, - * so we can safely collect pull_task() stats here rather than - * inside pull_task(). - */ - schedstat_add(sd, lb_gained[idle], pulled); - - if (all_pinned) - *all_pinned = pinned; - - return max_load_move - rem_load_move; -} - -/* - * move_tasks tries to move up to max_load_move weighted load from busiest to - * this_rq, as part of a balancing operation within domain "sd". - * Returns 1 if successful and 0 otherwise. - * - * Called with both runqueues locked. - */ -static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, - unsigned long max_load_move, - struct sched_domain *sd, enum cpu_idle_type idle, - int *all_pinned) -{ - const struct sched_class *class = sched_class_highest; - unsigned long total_load_moved = 0; - int this_best_prio = this_rq->curr->prio; - - do { - total_load_moved += - class->load_balance(this_rq, this_cpu, busiest, - max_load_move - total_load_moved, - sd, idle, all_pinned, &this_best_prio); - class = class->next; - } while (class && max_load_move > total_load_moved); - - return total_load_moved > 0; -} - -static int -iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle, - struct rq_iterator *iterator) -{ - struct task_struct *p = iterator->start(iterator->arg); - int pinned = 0; - - while (p) { - if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { - pull_task(busiest, p, this_rq, this_cpu); - /* - * Right now, this is only the second place pull_task() - * is called, so we can safely collect pull_task() - * stats here rather than inside pull_task(). - */ - schedstat_inc(sd, lb_gained[idle]); - - return 1; - } - p = iterator->next(iterator->arg); - } - - return 0; -} - -/* - * move_one_task tries to move exactly one task from busiest to this_rq, as - * part of active balancing operations within "domain". - * Returns 1 if successful and 0 otherwise. - * - * Called with both runqueues locked. - */ -static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, - struct sched_domain *sd, enum cpu_idle_type idle) -{ - const struct sched_class *class; - - for (class = sched_class_highest; class; class = class->next) - if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) - return 1; - - return 0; -} - -/* - * find_busiest_group finds and returns the busiest CPU group within the - * domain. It calculates and returns the amount of weighted load which - * should be moved to restore balance via the imbalance parameter. - */ -static struct sched_group * -find_busiest_group(struct sched_domain *sd, int this_cpu, - unsigned long *imbalance, enum cpu_idle_type idle, - int *sd_idle, cpumask_t *cpus, int *balance) -{ - struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; - unsigned long max_load, avg_load, total_load, this_load, total_pwr; - unsigned long max_pull; - unsigned long busiest_load_per_task, busiest_nr_running; - unsigned long this_load_per_task, this_nr_running; - int load_idx, group_imb = 0; -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) - int power_savings_balance = 1; - unsigned long leader_nr_running = 0, min_load_per_task = 0; - unsigned long min_nr_running = ULONG_MAX; - struct sched_group *group_min = NULL, *group_leader = NULL; -#endif - - max_load = this_load = total_load = total_pwr = 0; - busiest_load_per_task = busiest_nr_running = 0; - this_load_per_task = this_nr_running = 0; - if (idle == CPU_NOT_IDLE) - load_idx = sd->busy_idx; - else if (idle == CPU_NEWLY_IDLE) - load_idx = sd->newidle_idx; - else - load_idx = sd->idle_idx; - - do { - unsigned long load, group_capacity, max_cpu_load, min_cpu_load; - int local_group; - int i; - int __group_imb = 0; - unsigned int balance_cpu = -1, first_idle_cpu = 0; - unsigned long sum_nr_running, sum_weighted_load; - - local_group = cpu_isset(this_cpu, group->cpumask); - - if (local_group) - balance_cpu = first_cpu(group->cpumask); - - /* Tally up the load of all CPUs in the group */ - sum_weighted_load = sum_nr_running = avg_load = 0; - max_cpu_load = 0; - min_cpu_load = ~0UL; - - for_each_cpu_mask(i, group->cpumask) { - struct rq *rq; - - if (!cpu_isset(i, *cpus)) - continue; - - rq = cpu_rq(i); - - if (*sd_idle && rq->nr_running) - *sd_idle = 0; - - /* Bias balancing toward cpus of our domain */ - if (local_group) { - if (idle_cpu(i) && !first_idle_cpu) { - first_idle_cpu = 1; - balance_cpu = i; - } - - load = target_load(i, load_idx); - } else { - load = source_load(i, load_idx); - if (load > max_cpu_load) - max_cpu_load = load; - if (min_cpu_load > load) - min_cpu_load = load; - } - - avg_load += load; - sum_nr_running += rq->nr_running; - sum_weighted_load += weighted_cpuload(i); - } - - /* - * First idle cpu or the first cpu(busiest) in this sched group - * is eligible for doing load balancing at this and above - * domains. In the newly idle case, we will allow all the cpu's - * to do the newly idle load balance. - */ - if (idle != CPU_NEWLY_IDLE && local_group && - balance_cpu != this_cpu && balance) { - *balance = 0; - goto ret; - } - - total_load += avg_load; - total_pwr += group->__cpu_power; - - /* Adjust by relative CPU power of the group */ - avg_load = sg_div_cpu_power(group, - avg_load * SCHED_LOAD_SCALE); - - if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE) - __group_imb = 1; - - group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; - - if (local_group) { - this_load = avg_load; - this = group; - this_nr_running = sum_nr_running; - this_load_per_task = sum_weighted_load; - } else if (avg_load > max_load && - (sum_nr_running > group_capacity || __group_imb)) { - max_load = avg_load; - busiest = group; - busiest_nr_running = sum_nr_running; - busiest_load_per_task = sum_weighted_load; - group_imb = __group_imb; - } - -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) - /* - * Busy processors will not participate in power savings - * balance. - */ - if (idle == CPU_NOT_IDLE || - !(sd->flags & SD_POWERSAVINGS_BALANCE)) - goto group_next; - - /* - * If the local group is idle or completely loaded - * no need to do power savings balance at this domain - */ - if (local_group && (this_nr_running >= group_capacity || - !this_nr_running)) - power_savings_balance = 0; - - /* - * If a group is already running at full capacity or idle, - * don't include that group in power savings calculations - */ - if (!power_savings_balance || sum_nr_running >= group_capacity - || !sum_nr_running) - goto group_next; - - /* - * Calculate the group which has the least non-idle load. - * This is the group from where we need to pick up the load - * for saving power - */ - if ((sum_nr_running < min_nr_running) || - (sum_nr_running == min_nr_running && - first_cpu(group->cpumask) < - first_cpu(group_min->cpumask))) { - group_min = group; - min_nr_running = sum_nr_running; - min_load_per_task = sum_weighted_load / - sum_nr_running; - } - - /* - * Calculate the group which is almost near its - * capacity but still has some space to pick up some load - * from other group and save more power - */ - if (sum_nr_running <= group_capacity - 1) { - if (sum_nr_running > leader_nr_running || - (sum_nr_running == leader_nr_running && - first_cpu(group->cpumask) > - first_cpu(group_leader->cpumask))) { - group_leader = group; - leader_nr_running = sum_nr_running; - } - } -group_next: -#endif - group = group->next; - } while (group != sd->groups); - - if (!busiest || this_load >= max_load || busiest_nr_running == 0) - goto out_balanced; - - avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; - - if (this_load >= avg_load || - 100*max_load <= sd->imbalance_pct*this_load) - goto out_balanced; - - busiest_load_per_task /= busiest_nr_running; - if (group_imb) - busiest_load_per_task = min(busiest_load_per_task, avg_load); - - /* - * We're trying to get all the cpus to the average_load, so we don't - * want to push ourselves above the average load, nor do we wish to - * reduce the max loaded cpu below the average load, as either of these - * actions would just result in more rebalancing later, and ping-pong - * tasks around. Thus we look for the minimum possible imbalance. - * Negative imbalances (*we* are more loaded than anyone else) will - * be counted as no imbalance for these purposes -- we can't fix that - * by pulling tasks to us. Be careful of negative numbers as they'll - * appear as very large values with unsigned longs. - */ - if (max_load <= busiest_load_per_task) - goto out_balanced; - - /* - * In the presence of smp nice balancing, certain scenarios can have - * max load less than avg load(as we skip the groups at or below - * its cpu_power, while calculating max_load..) - */ - if (max_load < avg_load) { - *imbalance = 0; - goto small_imbalance; - } - - /* Don't want to pull so many tasks that a group would go idle */ - max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); - - /* How much load to actually move to equalise the imbalance */ - *imbalance = min(max_pull * busiest->__cpu_power, - (avg_load - this_load) * this->__cpu_power) - / SCHED_LOAD_SCALE; - - /* - * if *imbalance is less than the average load per runnable task - * there is no gaurantee that any tasks will be moved so we'll have - * a think about bumping its value to force at least one task to be - * moved - */ - if (*imbalance < busiest_load_per_task) { - unsigned long tmp, pwr_now, pwr_move; - unsigned int imbn; - -small_imbalance: - pwr_move = pwr_now = 0; - imbn = 2; - if (this_nr_running) { - this_load_per_task /= this_nr_running; - if (busiest_load_per_task > this_load_per_task) - imbn = 1; - } else - this_load_per_task = SCHED_LOAD_SCALE; - - if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= - busiest_load_per_task * imbn) { - *imbalance = busiest_load_per_task; - return busiest; - } - - /* - * OK, we don't have enough imbalance to justify moving tasks, - * however we may be able to increase total CPU power used by - * moving them. - */ - - pwr_now += busiest->__cpu_power * - min(busiest_load_per_task, max_load); - pwr_now += this->__cpu_power * - min(this_load_per_task, this_load); - pwr_now /= SCHED_LOAD_SCALE; - - /* Amount of load we'd subtract */ - tmp = sg_div_cpu_power(busiest, - busiest_load_per_task * SCHED_LOAD_SCALE); - if (max_load > tmp) - pwr_move += busiest->__cpu_power * - min(busiest_load_per_task, max_load - tmp); - - /* Amount of load we'd add */ - if (max_load * busiest->__cpu_power < - busiest_load_per_task * SCHED_LOAD_SCALE) - tmp = sg_div_cpu_power(this, - max_load * busiest->__cpu_power); - else - tmp = sg_div_cpu_power(this, - busiest_load_per_task * SCHED_LOAD_SCALE); - pwr_move += this->__cpu_power * - min(this_load_per_task, this_load + tmp); - pwr_move /= SCHED_LOAD_SCALE; - - /* Move if we gain throughput */ - if (pwr_move > pwr_now) - *imbalance = busiest_load_per_task; - } - - return busiest; - -out_balanced: -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) - if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) - goto ret; - - if (this == group_leader && group_leader != group_min) { - *imbalance = min_load_per_task; - return group_min; - } -#endif -ret: - *imbalance = 0; - return NULL; -} - -/* - * find_busiest_queue - find the busiest runqueue among the cpus in group. - */ -static struct rq * -find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, - unsigned long imbalance, cpumask_t *cpus) -{ - struct rq *busiest = NULL, *rq; - unsigned long max_load = 0; - int i; - - for_each_cpu_mask(i, group->cpumask) { - unsigned long wl; - - if (!cpu_isset(i, *cpus)) - continue; - - rq = cpu_rq(i); - wl = weighted_cpuload(i); - - if (rq->nr_running == 1 && wl > imbalance) - continue; - - if (wl > max_load) { - max_load = wl; - busiest = rq; - } - } - - return busiest; -} - -/* - * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but - * so long as it is large enough. - */ -#define MAX_PINNED_INTERVAL 512 - -/* - * Check this_cpu to ensure it is balanced within domain. Attempt to move - * tasks if there is an imbalance. - */ -static int load_balance(int this_cpu, struct rq *this_rq, - struct sched_domain *sd, enum cpu_idle_type idle, - int *balance) -{ - int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; - struct sched_group *group; - unsigned long imbalance; - struct rq *busiest; - cpumask_t cpus = CPU_MASK_ALL; - unsigned long flags; - - /* - * When power savings policy is enabled for the parent domain, idle - * sibling can pick up load irrespective of busy siblings. In this case, - * let the state of idle sibling percolate up as CPU_IDLE, instead of - * portraying it as CPU_NOT_IDLE. - */ - if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - sd_idle = 1; - - schedstat_inc(sd, lb_count[idle]); - -redo: - group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, - &cpus, balance); - - if (*balance == 0) - goto out_balanced; - - if (!group) { - schedstat_inc(sd, lb_nobusyg[idle]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, idle, imbalance, &cpus); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[idle]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[idle], imbalance); - - ld_moved = 0; - if (busiest->nr_running > 1) { - /* - * Attempt to move tasks. If find_busiest_group has found - * an imbalance but busiest->nr_running <= 1, the group is - * still unbalanced. ld_moved simply stays zero, so it is - * correctly treated as an imbalance. - */ - local_irq_save(flags); - double_rq_lock(this_rq, busiest); - ld_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, idle, &all_pinned); - double_rq_unlock(this_rq, busiest); - local_irq_restore(flags); - - /* - * some other cpu did the load balance for us. - */ - if (ld_moved && this_cpu != smp_processor_id()) - resched_cpu(this_cpu); - - /* All tasks on this runqueue were pinned by CPU affinity */ - if (unlikely(all_pinned)) { - cpu_clear(cpu_of(busiest), cpus); - if (!cpus_empty(cpus)) - goto redo; - goto out_balanced; - } - } - - if (!ld_moved) { - schedstat_inc(sd, lb_failed[idle]); - sd->nr_balance_failed++; - - if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { - - spin_lock_irqsave(&busiest->lock, flags); - - /* don't kick the migration_thread, if the curr - * task on busiest cpu can't be moved to this_cpu - */ - if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { - spin_unlock_irqrestore(&busiest->lock, flags); - all_pinned = 1; - goto out_one_pinned; - } - - if (!busiest->active_balance) { - busiest->active_balance = 1; - busiest->push_cpu = this_cpu; - active_balance = 1; - } - spin_unlock_irqrestore(&busiest->lock, flags); - if (active_balance) - wake_up_process(busiest->migration_thread); - - /* - * We've kicked active balancing, reset the failure - * counter. - */ - sd->nr_balance_failed = sd->cache_nice_tries+1; - } - } else - sd->nr_balance_failed = 0; - - if (likely(!active_balance)) { - /* We were unbalanced, so reset the balancing interval */ - sd->balance_interval = sd->min_interval; - } else { - /* - * If we've begun active balancing, start to back off. This - * case may not be covered by the all_pinned logic if there - * is only 1 task on the busy runqueue (because we don't call - * move_tasks). - */ - if (sd->balance_interval < sd->max_interval) - sd->balance_interval *= 2; - } - - if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - return ld_moved; - -out_balanced: - schedstat_inc(sd, lb_balanced[idle]); - - sd->nr_balance_failed = 0; - -out_one_pinned: - /* tune up the balancing interval */ - if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || - (sd->balance_interval < sd->max_interval)) - sd->balance_interval *= 2; - - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - return 0; -} - -/* - * Check this_cpu to ensure it is balanced within domain. Attempt to move - * tasks if there is an imbalance. - * - * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). - * this_rq is locked. - */ -static int -load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) -{ - struct sched_group *group; - struct rq *busiest = NULL; - unsigned long imbalance; - int ld_moved = 0; - int sd_idle = 0; - int all_pinned = 0; - cpumask_t cpus = CPU_MASK_ALL; - - /* - * When power savings policy is enabled for the parent domain, idle - * sibling can pick up load irrespective of busy siblings. In this case, - * let the state of idle sibling percolate up as IDLE, instead of - * portraying it as CPU_NOT_IDLE. - */ - if (sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - sd_idle = 1; - - schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); -redo: - group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, - &sd_idle, &cpus, NULL); - if (!group) { - schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, - &cpus); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); - - ld_moved = 0; - if (busiest->nr_running > 1) { - /* Attempt to move tasks */ - double_lock_balance(this_rq, busiest); - /* this_rq->clock is already updated */ - update_rq_clock(busiest); - ld_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, CPU_NEWLY_IDLE, - &all_pinned); - spin_unlock(&busiest->lock); - - if (unlikely(all_pinned)) { - cpu_clear(cpu_of(busiest), cpus); - if (!cpus_empty(cpus)) - goto redo; - } - } - - if (!ld_moved) { - schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - } else - sd->nr_balance_failed = 0; - - return ld_moved; - -out_balanced: - schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && - !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) - return -1; - sd->nr_balance_failed = 0; - - return 0; -} - -/* - * idle_balance is called by schedule() if this_cpu is about to become - * idle. Attempts to pull tasks from other CPUs. - */ -static void idle_balance(int this_cpu, struct rq *this_rq) -{ - struct sched_domain *sd; - int pulled_task = -1; - unsigned long next_balance = jiffies + HZ; - - for_each_domain(this_cpu, sd) { - unsigned long interval; - - if (!(sd->flags & SD_LOAD_BALANCE)) - continue; - - if (sd->flags & SD_BALANCE_NEWIDLE) - /* If we've pulled tasks over stop searching: */ - pulled_task = load_balance_newidle(this_cpu, - this_rq, sd); - - interval = msecs_to_jiffies(sd->balance_interval); - if (time_after(next_balance, sd->last_balance + interval)) - next_balance = sd->last_balance + interval; - if (pulled_task) - break; - } - if (pulled_task || time_after(jiffies, this_rq->next_balance)) { - /* - * We are going idle. next_balance may be set based on - * a busy processor. So reset next_balance. - */ - this_rq->next_balance = next_balance; - } -} - -/* - * active_load_balance is run by migration threads. It pushes running tasks - * off the busiest CPU onto idle CPUs. It requires at least 1 task to be - * running on each physical CPU where possible, and avoids physical / - * logical imbalances. - * - * Called with busiest_rq locked. - */ -static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) -{ - int target_cpu = busiest_rq->push_cpu; - struct sched_domain *sd; - struct rq *target_rq; - - /* Is there any task to move? */ - if (busiest_rq->nr_running <= 1) - return; - - target_rq = cpu_rq(target_cpu); - - /* - * This condition is "impossible", if it occurs - * we need to fix it. Originally reported by - * Bjorn Helgaas on a 128-cpu setup. - */ - BUG_ON(busiest_rq == target_rq); - - /* move a task from busiest_rq to target_rq */ - double_lock_balance(busiest_rq, target_rq); - update_rq_clock(busiest_rq); - update_rq_clock(target_rq); - - /* Search for an sd spanning us and the target CPU. */ - for_each_domain(target_cpu, sd) { - if ((sd->flags & SD_LOAD_BALANCE) && - cpu_isset(busiest_cpu, sd->span)) - break; - } - - if (likely(sd)) { - schedstat_inc(sd, alb_count); - - if (move_one_task(target_rq, target_cpu, busiest_rq, - sd, CPU_IDLE)) - schedstat_inc(sd, alb_pushed); - else - schedstat_inc(sd, alb_failed); - } - spin_unlock(&target_rq->lock); -} - -#ifdef CONFIG_NO_HZ -static struct { - atomic_t load_balancer; - cpumask_t cpu_mask; -} nohz ____cacheline_aligned = { - .load_balancer = ATOMIC_INIT(-1), - .cpu_mask = CPU_MASK_NONE, -}; - -/* - * This routine will try to nominate the ilb (idle load balancing) - * owner among the cpus whose ticks are stopped. ilb owner will do the idle - * load balancing on behalf of all those cpus. If all the cpus in the system - * go into this tickless mode, then there will be no ilb owner (as there is - * no need for one) and all the cpus will sleep till the next wakeup event - * arrives... - * - * For the ilb owner, tick is not stopped. And this tick will be used - * for idle load balancing. ilb owner will still be part of - * nohz.cpu_mask.. - * - * While stopping the tick, this cpu will become the ilb owner if there - * is no other owner. And will be the owner till that cpu becomes busy - * or if all cpus in the system stop their ticks at which point - * there is no need for ilb owner. - * - * When the ilb owner becomes busy, it nominates another owner, during the - * next busy scheduler_tick() - */ -int select_nohz_load_balancer(int stop_tick) -{ - int cpu = smp_processor_id(); - - if (stop_tick) { - cpu_set(cpu, nohz.cpu_mask); - cpu_rq(cpu)->in_nohz_recently = 1; - - /* - * If we are going offline and still the leader, give up! - */ - if (cpu_is_offline(cpu) && - atomic_read(&nohz.load_balancer) == cpu) { - if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) - BUG(); - return 0; - } - - /* time for ilb owner also to sleep */ - if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { - if (atomic_read(&nohz.load_balancer) == cpu) - atomic_set(&nohz.load_balancer, -1); - return 0; - } - - if (atomic_read(&nohz.load_balancer) == -1) { - /* make me the ilb owner */ - if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) - return 1; - } else if (atomic_read(&nohz.load_balancer) == cpu) - return 1; - } else { - if (!cpu_isset(cpu, nohz.cpu_mask)) - return 0; - - cpu_clear(cpu, nohz.cpu_mask); - - if (atomic_read(&nohz.load_balancer) == cpu) - if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) - BUG(); - } - return 0; -} -#endif - -static DEFINE_SPINLOCK(balancing); - -/* - * It checks each scheduling domain to see if it is due to be balanced, - * and initiates a balancing operation if so. - * - * Balancing parameters are set up in arch_init_sched_domains. - */ -static void rebalance_domains(int cpu, enum cpu_idle_type idle) -{ - int balance = 1; - struct rq *rq = cpu_rq(cpu); - unsigned long interval; - struct sched_domain *sd; - /* Earliest time when we have to do rebalance again */ - unsigned long next_balance = jiffies + 60*HZ; - int update_next_balance = 0; - - for_each_domain(cpu, sd) { - if (!(sd->flags & SD_LOAD_BALANCE)) - continue; - - interval = sd->balance_interval; - if (idle != CPU_IDLE) - interval *= sd->busy_factor; - - /* scale ms to jiffies */ - interval = msecs_to_jiffies(interval); - if (unlikely(!interval)) - interval = 1; - if (interval > HZ*NR_CPUS/10) - interval = HZ*NR_CPUS/10; - - - if (sd->flags & SD_SERIALIZE) { - if (!spin_trylock(&balancing)) - goto out; - } - - if (time_after_eq(jiffies, sd->last_balance + interval)) { - if (load_balance(cpu, rq, sd, idle, &balance)) { - /* - * We've pulled tasks over so either we're no - * longer idle, or one of our SMT siblings is - * not idle. - */ - idle = CPU_NOT_IDLE; - } - sd->last_balance = jiffies; - } - if (sd->flags & SD_SERIALIZE) - spin_unlock(&balancing); -out: - if (time_after(next_balance, sd->last_balance + interval)) { - next_balance = sd->last_balance + interval; - update_next_balance = 1; - } - - /* - * Stop the load balance at this level. There is another - * CPU in our sched group which is doing load balancing more - * actively. - */ - if (!balance) - break; - } - - /* - * next_balance will be updated only when there is a need. - * When the cpu is attached to null domain for ex, it will not be - * updated. - */ - if (likely(update_next_balance)) - rq->next_balance = next_balance; -} - -/* - * run_rebalance_domains is triggered when needed from the scheduler tick. - * In CONFIG_NO_HZ case, the idle load balance owner will do the - * rebalancing for all the cpus for whom scheduler ticks are stopped. - */ -static void run_rebalance_domains(struct softirq_action *h) -{ - int this_cpu = smp_processor_id(); - struct rq *this_rq = cpu_rq(this_cpu); - enum cpu_idle_type idle = this_rq->idle_at_tick ? - CPU_IDLE : CPU_NOT_IDLE; - - rebalance_domains(this_cpu, idle); - -#ifdef CONFIG_NO_HZ - /* - * If this cpu is the owner for idle load balancing, then do the - * balancing on behalf of the other idle cpus whose ticks are - * stopped. - */ - if (this_rq->idle_at_tick && - atomic_read(&nohz.load_balancer) == this_cpu) { - cpumask_t cpus = nohz.cpu_mask; - struct rq *rq; - int balance_cpu; - - cpu_clear(this_cpu, cpus); - for_each_cpu_mask(balance_cpu, cpus) { - /* - * If this cpu gets work to do, stop the load balancing - * work being done for other cpus. Next load - * balancing owner will pick it up. - */ - if (need_resched()) - break; - - rebalance_domains(balance_cpu, CPU_IDLE); - - rq = cpu_rq(balance_cpu); - if (time_after(this_rq->next_balance, rq->next_balance)) - this_rq->next_balance = rq->next_balance; - } - } -#endif -} - -/* - * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. - * - * In case of CONFIG_NO_HZ, this is the place where we nominate a new - * idle load balancing owner or decide to stop the periodic load balancing, - * if the whole system is idle. - */ -static inline void trigger_load_balance(struct rq *rq, int cpu) -{ -#ifdef CONFIG_NO_HZ - /* - * If we were in the nohz mode recently and busy at the current - * scheduler tick, then check if we need to nominate new idle - * load balancer. - */ - if (rq->in_nohz_recently && !rq->idle_at_tick) { - rq->in_nohz_recently = 0; - - if (atomic_read(&nohz.load_balancer) == cpu) { - cpu_clear(cpu, nohz.cpu_mask); - atomic_set(&nohz.load_balancer, -1); - } - - if (atomic_read(&nohz.load_balancer) == -1) { - /* - * simple selection for now: Nominate the - * first cpu in the nohz list to be the next - * ilb owner. - * - * TBD: Traverse the sched domains and nominate - * the nearest cpu in the nohz.cpu_mask. - */ - int ilb = first_cpu(nohz.cpu_mask); - - if (ilb != NR_CPUS) - resched_cpu(ilb); - } - } - - /* - * If this cpu is idle and doing idle load balancing for all the - * cpus with ticks stopped, is it time for that to stop? - */ - if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && - cpus_weight(nohz.cpu_mask) == num_online_cpus()) { - resched_cpu(cpu); - return; - } - - /* - * If this cpu is idle and the idle load balancing is done by - * someone else, then no need raise the SCHED_SOFTIRQ - */ - if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && - cpu_isset(cpu, nohz.cpu_mask)) - return; -#endif - if (time_after_eq(jiffies, rq->next_balance)) - raise_softirq(SCHED_SOFTIRQ); -} - -#else /* CONFIG_SMP */ - -/* - * on UP we do not need to balance between CPUs: - */ -static inline void idle_balance(int cpu, struct rq *rq) -{ -} - -#endif - -DEFINE_PER_CPU(struct kernel_stat, kstat); - -EXPORT_PER_CPU_SYMBOL(kstat); - -/* - * Return p->sum_exec_runtime plus any more ns on the sched_clock - * that have not yet been banked in case the task is currently running. - */ -unsigned long long task_sched_runtime(struct task_struct *p) -{ - unsigned long flags; - u64 ns, delta_exec; - struct rq *rq; - - rq = task_rq_lock(p, &flags); - ns = p->se.sum_exec_runtime; - if (task_current(rq, p)) { - update_rq_clock(rq); - delta_exec = rq->clock - p->se.exec_start; - if ((s64)delta_exec > 0) - ns += delta_exec; - } - task_rq_unlock(rq, &flags); - - return ns; -} - -/* - * Account user cpu time to a process. - * @p: the process that the cpu time gets accounted to - * @cputime: the cpu time spent in user space since the last update - */ -void account_user_time(struct task_struct *p, cputime_t cputime) -{ - struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; - cputime64_t tmp; - - p->utime = cputime_add(p->utime, cputime); - - /* Add user time to cpustat. */ - tmp = cputime_to_cputime64(cputime); - if (TASK_NICE(p) > 0) - cpustat->nice = cputime64_add(cpustat->nice, tmp); - else - cpustat->user = cputime64_add(cpustat->user, tmp); -} - -/* - * 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 - */ -static void account_guest_time(struct task_struct *p, cputime_t cputime) -{ - cputime64_t tmp; - struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; - - tmp = cputime_to_cputime64(cputime); - - p->utime = cputime_add(p->utime, cputime); - p->gtime = cputime_add(p->gtime, cputime); - - cpustat->user = cputime64_add(cpustat->user, tmp); - cpustat->guest = cputime64_add(cpustat->guest, tmp); -} - -/* - * Account scaled user cpu time to a process. - * @p: the process that the cpu time gets accounted to - * @cputime: the cpu time spent in user space since the last update - */ -void account_user_time_scaled(struct task_struct *p, cputime_t cputime) -{ - p->utimescaled = cputime_add(p->utimescaled, cputime); -} - -/* - * 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 - */ -void account_system_time(struct task_struct *p, int hardirq_offset, - cputime_t cputime) -{ - struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; - struct rq *rq = this_rq(); - cputime64_t tmp; - - if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) - return account_guest_time(p, cputime); - - p->stime = cputime_add(p->stime, cputime); - - /* Add system time to cpustat. */ - tmp = cputime_to_cputime64(cputime); - if (hardirq_count() - hardirq_offset) - cpustat->irq = cputime64_add(cpustat->irq, tmp); - else if (softirq_count()) - cpustat->softirq = cputime64_add(cpustat->softirq, tmp); - else if (p != rq->idle) - cpustat->system = cputime64_add(cpustat->system, tmp); - else if (atomic_read(&rq->nr_iowait) > 0) - cpustat->iowait = cputime64_add(cpustat->iowait, tmp); - else - cpustat->idle = cputime64_add(cpustat->idle, tmp); - /* Account for system time used */ - acct_update_integrals(p); -} - -/* - * Account scaled 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 - */ -void account_system_time_scaled(struct task_struct *p, cputime_t cputime) -{ - p->stimescaled = cputime_add(p->stimescaled, cputime); -} - -/* - * Account for involuntary wait time. - * @p: the process from which the cpu time has been stolen - * @steal: the cpu time spent in involuntary wait - */ -void account_steal_time(struct task_struct *p, cputime_t steal) -{ - struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; - cputime64_t tmp = cputime_to_cputime64(steal); - struct rq *rq = this_rq(); - - if (p == rq->idle) { - p->stime = cputime_add(p->stime, steal); - if (atomic_read(&rq->nr_iowait) > 0) - cpustat->iowait = cputime64_add(cpustat->iowait, tmp); - else - cpustat->idle = cputime64_add(cpustat->idle, tmp); - } else - cpustat->steal = cputime64_add(cpustat->steal, tmp); -} - -/* - * This function gets called by the timer code, with HZ frequency. - * We call it with interrupts disabled. - * - * It also gets called by the fork code, when changing the parent's - * timeslices. - */ -void scheduler_tick(void) -{ - int cpu = smp_processor_id(); - struct rq *rq = cpu_rq(cpu); - struct task_struct *curr = rq->curr; - u64 next_tick = rq->tick_timestamp + TICK_NSEC; - - spin_lock(&rq->lock); - __update_rq_clock(rq); - /* - * Let rq->clock advance by at least TICK_NSEC: - */ - if (unlikely(rq->clock < next_tick)) { - rq->clock = next_tick; - rq->clock_underflows++; - } - rq->tick_timestamp = rq->clock; - update_cpu_load(rq); - curr->sched_class->task_tick(rq, curr, 0); - update_sched_rt_period(rq); - spin_unlock(&rq->lock); - -#ifdef CONFIG_SMP - rq->idle_at_tick = idle_cpu(cpu); - trigger_load_balance(rq, cpu); -#endif -} - -#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) - -void __kprobes add_preempt_count(int val) -{ - /* - * Underflow? - */ - if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) - return; - preempt_count() += val; - /* - * Spinlock count overflowing soon? - */ - DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= - PREEMPT_MASK - 10); -} -EXPORT_SYMBOL(add_preempt_count); - -void __kprobes sub_preempt_count(int val) -{ - /* - * 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; - - preempt_count() -= val; -} -EXPORT_SYMBOL(sub_preempt_count); - -#endif - -/* - * Print scheduling while atomic bug: - */ -static noinline void __schedule_bug(struct task_struct *prev) -{ - struct pt_regs *regs = get_irq_regs(); - - printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", - prev->comm, prev->pid, preempt_count()); - - debug_show_held_locks(prev); - if (irqs_disabled()) - print_irqtrace_events(prev); - - if (regs) - show_regs(regs); - else - dump_stack(); -} - -/* - * Various schedule()-time debugging checks and statistics: - */ -static inline void schedule_debug(struct task_struct *prev) -{ - /* - * Test if we are atomic. Since do_exit() needs to call into - * schedule() atomically, we ignore that path for now. - * Otherwise, whine if we are scheduling when we should not be. - */ - if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) - __schedule_bug(prev); - - profile_hit(SCHED_PROFILING, __builtin_return_address(0)); - - schedstat_inc(this_rq(), sched_count); -#ifdef CONFIG_SCHEDSTATS - if (unlikely(prev->lock_depth >= 0)) { - schedstat_inc(this_rq(), bkl_count); - schedstat_inc(prev, sched_info.bkl_count); - } -#endif -} - -/* - * Pick up the highest-prio task: - */ -static inline struct task_struct * -pick_next_task(struct rq *rq, struct task_struct *prev) -{ - const struct sched_class *class; - struct task_struct *p; - - /* - * Optimization: we know that if all tasks are in - * the fair class we can call that function directly: - */ - if (likely(rq->nr_running == rq->cfs.nr_running)) { - p = fair_sched_class.pick_next_task(rq); - if (likely(p)) - return p; - } - - class = sched_class_highest; - for ( ; ; ) { - p = class->pick_next_task(rq); - if (p) - return p; - /* - * Will never be NULL as the idle class always - * returns a non-NULL p: - */ - class = class->next; - } -} - -/* - * schedule() is the main scheduler function. - */ -asmlinkage void __sched schedule(void) -{ - struct task_struct *prev, *next; - unsigned long *switch_count; - struct rq *rq; - int cpu; - -need_resched: - preempt_disable(); - cpu = smp_processor_id(); - rq = cpu_rq(cpu); - rcu_qsctr_inc(cpu); - prev = rq->curr; - switch_count = &prev->nivcsw; - - release_kernel_lock(prev); -need_resched_nonpreemptible: - - schedule_debug(prev); - - hrtick_clear(rq); - - /* - * Do the rq-clock update outside the rq lock: - */ - local_irq_disable(); - __update_rq_clock(rq); - spin_lock(&rq->lock); - clear_tsk_need_resched(prev); - - if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { - if (unlikely((prev->state & TASK_INTERRUPTIBLE) && - signal_pending(prev))) { - prev->state = TASK_RUNNING; - } else { - deactivate_task(rq, prev, 1); - } - switch_count = &prev->nvcsw; - } - -#ifdef CONFIG_SMP - if (prev->sched_class->pre_schedule) - prev->sched_class->pre_schedule(rq, prev); -#endif - - if (unlikely(!rq->nr_running)) - idle_balance(cpu, rq); - - prev->sched_class->put_prev_task(rq, prev); - next = pick_next_task(rq, prev); - - sched_info_switch(prev, next); - - if (likely(prev != next)) { - rq->nr_switches++; - rq->curr = next; - ++*switch_count; - - context_switch(rq, prev, next); /* unlocks the rq */ - /* - * the context switch might have flipped the stack from under - * us, hence refresh the local variables. - */ - cpu = smp_processor_id(); - rq = cpu_rq(cpu); - } else - spin_unlock_irq(&rq->lock); - - hrtick_set(rq); - - if (unlikely(reacquire_kernel_lock(current) < 0)) - goto need_resched_nonpreemptible; - - preempt_enable_no_resched(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; -} -EXPORT_SYMBOL(schedule); - -#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 preempt_schedule(void) -{ - struct thread_info *ti = current_thread_info(); - struct task_struct *task = current; - int saved_lock_depth; - - /* - * 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(PREEMPT_ACTIVE); - - /* - * We keep the big kernel semaphore locked, but we - * clear ->lock_depth so that schedule() doesnt - * auto-release the semaphore: - */ - saved_lock_depth = task->lock_depth; - task->lock_depth = -1; - schedule(); - task->lock_depth = saved_lock_depth; - sub_preempt_count(PREEMPT_ACTIVE); - - /* - * Check again in case we missed a preemption opportunity - * between schedule and now. - */ - barrier(); - } while (unlikely(test_thread_flag(TIF_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(); - struct task_struct *task = current; - int saved_lock_depth; - - /* Catch callers which need to be fixed */ - BUG_ON(ti->preempt_count || !irqs_disabled()); - - do { - add_preempt_count(PREEMPT_ACTIVE); - - /* - * We keep the big kernel semaphore locked, but we - * clear ->lock_depth so that schedule() doesnt - * auto-release the semaphore: - */ - saved_lock_depth = task->lock_depth; - task->lock_depth = -1; - local_irq_enable(); - schedule(); - local_irq_disable(); - task->lock_depth = saved_lock_depth; - sub_preempt_count(PREEMPT_ACTIVE); - - /* - * Check again in case we missed a preemption opportunity - * between schedule and now. - */ - barrier(); - } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); -} - -#endif /* CONFIG_PREEMPT */ - -int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, - void *key) -{ - return try_to_wake_up(curr->private, mode, sync); -} -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 sync, void *key) -{ - wait_queue_t *curr, *next; - - list_for_each_entry_safe(curr, next, &q->task_list, task_list) { - unsigned flags = curr->flags; - - if (curr->func(curr, mode, sync, 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 - */ -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); -} - -/** - * __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 'synchronized' - * 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 */ - -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); - -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); - - wait.flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(&x->wait, &wait); - do { - if ((state == TASK_INTERRUPTIBLE && - signal_pending(current)) || - (state == TASK_KILLABLE && - fatal_signal_pending(current))) { - __remove_wait_queue(&x->wait, &wait); - return -ERESTARTSYS; - } - __set_current_state(state); - spin_unlock_irq(&x->wait.lock); - timeout = schedule_timeout(timeout); - spin_lock_irq(&x->wait.lock); - if (!timeout) { - __remove_wait_queue(&x->wait, &wait); - return timeout; - } - } while (!x->done); - __remove_wait_queue(&x->wait, &wait); - } - x->done--; - return timeout; -} - -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; -} - -void __sched wait_for_completion(struct completion *x) -{ - wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); -} -EXPORT_SYMBOL(wait_for_completion); - -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); - -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); - -unsigned 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); - -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); - -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 oldprio, on_rq, running; - struct rq *rq; - const struct sched_class *prev_class = p->sched_class; - - BUG_ON(prio < 0 || prio > MAX_PRIO); - - rq = task_rq_lock(p, &flags); - update_rq_clock(rq); - - oldprio = p->prio; - on_rq = p->se.on_rq; - running = task_current(rq, p); - if (on_rq) - dequeue_task(rq, p, 0); - if (running) - p->sched_class->put_prev_task(rq, p); - - if (rt_prio(prio)) - p->sched_class = &rt_sched_class; - else - p->sched_class = &fair_sched_class; - - p->prio = prio; - - if (running) - p->sched_class->set_curr_task(rq); - if (on_rq) { - enqueue_task(rq, p, 0); - - check_class_changed(rq, p, prev_class, oldprio, running); - } - task_rq_unlock(rq, &flags); -} - -#endif - -void set_user_nice(struct task_struct *p, long nice) -{ - int old_prio, delta, on_rq; - unsigned long flags; - struct rq *rq; - - if (TASK_NICE(p) == nice || nice < -20 || nice > 19) - return; - /* - * We have to be careful, if called from sys_setpriority(), - * the task might be in the middle of scheduling on another CPU. - */ - rq = task_rq_lock(p, &flags); - update_rq_clock(rq); - /* - * 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 - * SCHED_FIFO/SCHED_RR: - */ - if (task_has_rt_policy(p)) { - p->static_prio = NICE_TO_PRIO(nice); - goto out_unlock; - } - on_rq = p->se.on_rq; - if (on_rq) { - dequeue_task(rq, p, 0); - dec_load(rq, p); - } - - p->static_prio = NICE_TO_PRIO(nice); - set_load_weight(p); - old_prio = p->prio; - p->prio = effective_prio(p); - delta = p->prio - old_prio; - - if (on_rq) { - enqueue_task(rq, p, 0); - inc_load(rq, p); - /* - * If the task increased its priority or is running and - * lowered its priority, then reschedule its CPU: - */ - if (delta < 0 || (delta > 0 && task_running(rq, p))) - resched_task(rq->curr); - } -out_unlock: - task_rq_unlock(rq, &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 <= p->signal->rlim[RLIMIT_NICE].rlim_cur || - 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. - */ -asmlinkage long sys_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 = PRIO_TO_NICE(current->static_prio) + 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 -200. Normal tasks are centered - * around 0, value goes from -16 to +15. - */ -int task_prio(const struct task_struct *p) -{ - return p->prio - MAX_RT_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(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 struct task_struct *find_process_by_pid(pid_t pid) -{ - return pid ? find_task_by_vpid(pid) : current; -} - -/* Actually do priority change: must hold rq lock. */ -static void -__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) -{ - BUG_ON(p->se.on_rq); - - p->policy = policy; - switch (p->policy) { - case SCHED_NORMAL: - case SCHED_BATCH: - case SCHED_IDLE: - p->sched_class = &fair_sched_class; - break; - case SCHED_FIFO: - case SCHED_RR: - p->sched_class = &rt_sched_class; - break; - } - - p->rt_priority = prio; - p->normal_prio = normal_prio(p); - /* we are holding p->pi_lock already */ - p->prio = rt_mutex_getprio(p); - set_load_weight(p); -} - -/** - * 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, - struct sched_param *param) -{ - int retval, oldprio, oldpolicy = -1, on_rq, running; - unsigned long flags; - const struct sched_class *prev_class = p->sched_class; - struct rq *rq; - - /* may grab non-irq protected spin_locks */ - BUG_ON(in_interrupt()); -recheck: - /* double check policy once rq lock held */ - if (policy < 0) - policy = oldpolicy = p->policy; - else if (policy != SCHED_FIFO && policy != SCHED_RR && - policy != SCHED_NORMAL && policy != SCHED_BATCH && - policy != SCHED_IDLE) - return -EINVAL; - /* - * Valid priorities for SCHED_FIFO and SCHED_RR are - * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, - * SCHED_BATCH and SCHED_IDLE 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 (rt_policy(policy) != (param->sched_priority != 0)) - return -EINVAL; - - /* - * Allow unprivileged RT tasks to decrease priority: - */ - if (!capable(CAP_SYS_NICE)) { - if (rt_policy(policy)) { - unsigned long rlim_rtprio; - - if (!lock_task_sighand(p, &flags)) - return -ESRCH; - rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; - unlock_task_sighand(p, &flags); - - /* 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; - } - /* - * Like positive nice levels, dont allow tasks to - * move out of SCHED_IDLE either: - */ - if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) - return -EPERM; - - /* can't change other user's priorities */ - if ((current->euid != p->euid) && - (current->euid != p->uid)) - return -EPERM; - } - -#ifdef CONFIG_RT_GROUP_SCHED - /* - * Do not allow realtime tasks into groups that have no runtime - * assigned. - */ - if (rt_policy(policy) && task_group(p)->rt_runtime == 0) - return -EPERM; -#endif - - retval = security_task_setscheduler(p, policy, param); - if (retval) - return retval; - /* - * make sure no PI-waiters arrive (or leave) while we are - * changing the priority of the task: - */ - spin_lock_irqsave(&p->pi_lock, flags); - /* - * To be able to change p->policy safely, the apropriate - * runqueue lock must be held. - */ - rq = __task_rq_lock(p); - /* recheck policy now with rq lock held */ - if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { - policy = oldpolicy = -1; - __task_rq_unlock(rq); - spin_unlock_irqrestore(&p->pi_lock, flags); - goto recheck; - } - update_rq_clock(rq); - on_rq = p->se.on_rq; - running = task_current(rq, p); - if (on_rq) - deactivate_task(rq, p, 0); - if (running) - p->sched_class->put_prev_task(rq, p); - - oldprio = p->prio; - __setscheduler(rq, p, policy, param->sched_priority); - - if (running) - p->sched_class->set_curr_task(rq); - if (on_rq) { - activate_task(rq, p, 0); - - check_class_changed(rq, p, prev_class, oldprio, running); - } - __task_rq_unlock(rq); - spin_unlock_irqrestore(&p->pi_lock, flags); - - rt_mutex_adjust_pi(p); - - return 0; -} -EXPORT_SYMBOL_GPL(sched_setscheduler); - -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. - */ -asmlinkage long sys_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. - */ -asmlinkage long sys_sched_getscheduler(pid_t pid) -{ - struct task_struct *p; - int retval; - - if (pid < 0) - return -EINVAL; - - retval = -ESRCH; - read_lock(&tasklist_lock); - p = find_process_by_pid(pid); - if (p) { - retval = security_task_getscheduler(p); - if (!retval) - retval = p->policy; - } - read_unlock(&tasklist_lock); - return retval; -} - -/** - * sys_sched_getscheduler - get the RT priority of a thread - * @pid: the pid in question. - * @param: structure containing the RT priority. - */ -asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) -{ - struct sched_param lp; - struct task_struct *p; - int retval; - - if (!param || pid < 0) - return -EINVAL; - - read_lock(&tasklist_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; - read_unlock(&tasklist_lock); - - /* - * This one might sleep, we cannot do it with a spinlock held ... - */ - retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; - - return retval; - -out_unlock: - read_unlock(&tasklist_lock); - return retval; -} - -long sched_setaffinity(pid_t pid, cpumask_t new_mask) -{ - cpumask_t cpus_allowed; - struct task_struct *p; - int retval; - - get_online_cpus(); - read_lock(&tasklist_lock); - - p = find_process_by_pid(pid); - if (!p) { - read_unlock(&tasklist_lock); - put_online_cpus(); - return -ESRCH; - } - - /* - * It is not safe to call set_cpus_allowed with the - * tasklist_lock held. We will bump the task_struct's - * usage count and then drop tasklist_lock. - */ - get_task_struct(p); - read_unlock(&tasklist_lock); - - retval = -EPERM; - if ((current->euid != p->euid) && (current->euid != p->uid) && - !capable(CAP_SYS_NICE)) - goto out_unlock; - - retval = security_task_setscheduler(p, 0, NULL); - if (retval) - goto out_unlock; - - cpus_allowed = cpuset_cpus_allowed(p); - cpus_and(new_mask, new_mask, cpus_allowed); - again: - retval = set_cpus_allowed(p, new_mask); - - if (!retval) { - cpus_allowed = cpuset_cpus_allowed(p); - if (!cpus_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 - */ - new_mask = cpus_allowed; - goto again; - } - } -out_unlock: - 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 - */ -asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, - unsigned long __user *user_mask_ptr) -{ - cpumask_t new_mask; - int retval; - - retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); - if (retval) - return retval; - - return sched_setaffinity(pid, new_mask); -} - -/* - * Represents all cpu's present in the system - * In systems capable of hotplug, this map could dynamically grow - * as new cpu's are detected in the system via any platform specific - * method, such as ACPI for e.g. - */ - -cpumask_t cpu_present_map __read_mostly; -EXPORT_SYMBOL(cpu_present_map); - -#ifndef CONFIG_SMP -cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; -EXPORT_SYMBOL(cpu_online_map); - -cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; -EXPORT_SYMBOL(cpu_possible_map); -#endif - -long sched_getaffinity(pid_t pid, cpumask_t *mask) -{ - struct task_struct *p; - int retval; - - get_online_cpus(); - read_lock(&tasklist_lock); - - retval = -ESRCH; - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; - - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; - - cpus_and(*mask, p->cpus_allowed, cpu_online_map); - -out_unlock: - read_unlock(&tasklist_lock); - 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 - */ -asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, - unsigned long __user *user_mask_ptr) -{ - int ret; - cpumask_t mask; - - if (len < sizeof(cpumask_t)) - return -EINVAL; - - ret = sched_getaffinity(pid, &mask); - if (ret < 0) - return ret; - - if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) - return -EFAULT; - - return sizeof(cpumask_t); -} - -/** - * sys_sched_yield - yield the current processor to other threads. - * - * This function yields the current CPU to other tasks. If there are no - * other threads running on this CPU then this function will return. - */ -asmlinkage long sys_sched_yield(void) -{ - struct rq *rq = this_rq_lock(); - - schedstat_inc(rq, yld_count); - current->sched_class->yield_task(rq); - - /* - * Since we are going to call schedule() anyway, there's - * no need to preempt or enable interrupts: - */ - __release(rq->lock); - spin_release(&rq->lock.dep_map, 1, _THIS_IP_); - _raw_spin_unlock(&rq->lock); - preempt_enable_no_resched(); - - schedule(); - - return 0; -} - -static void __cond_resched(void) -{ -#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP - __might_sleep(__FILE__, __LINE__); -#endif - /* - * The BKS might be reacquired before we have dropped - * PREEMPT_ACTIVE, which could trigger a second - * cond_resched() call. - */ - do { - add_preempt_count(PREEMPT_ACTIVE); - schedule(); - sub_preempt_count(PREEMPT_ACTIVE); - } while (need_resched()); -} - -#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY) -int __sched _cond_resched(void) -{ - if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && - system_state == SYSTEM_RUNNING) { - __cond_resched(); - return 1; - } - return 0; -} -EXPORT_SYMBOL(_cond_resched); -#endif - -/* - * cond_resched_lock() - if a reschedule is pending, drop the given lock, - * call schedule, and on return reacquire the lock. - * - * This works OK both with and without CONFIG_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 = need_resched() && system_state == SYSTEM_RUNNING; - int ret = 0; - - if (spin_needbreak(lock) || resched) { - spin_unlock(lock); - if (resched && need_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 (need_resched() && system_state == SYSTEM_RUNNING) { - 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); - -/* - * 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_get_cpu_var(runqueues); - - delayacct_blkio_start(); - atomic_inc(&rq->nr_iowait); - schedule(); - atomic_dec(&rq->nr_iowait); - delayacct_blkio_end(); -} -EXPORT_SYMBOL(io_schedule); - -long __sched io_schedule_timeout(long timeout) -{ - struct rq *rq = &__raw_get_cpu_var(runqueues); - long ret; - - delayacct_blkio_start(); - atomic_inc(&rq->nr_iowait); - ret = schedule_timeout(timeout); - 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. - */ -asmlinkage long sys_sched_get_priority_max(int policy) -{ - int ret = -EINVAL; - - switch (policy) { - case SCHED_FIFO: - case SCHED_RR: - ret = MAX_USER_RT_PRIO-1; - break; - case SCHED_NORMAL: - case SCHED_BATCH: - case SCHED_IDLE: - ret = 0; - break; - } - return ret; -} - -/** - * sys_sched_get_priority_min - return minimum RT priority. - * @policy: scheduling class. - * - * this syscall returns the minimum rt_priority that can be used - * by a given scheduling class. - */ -asmlinkage long sys_sched_get_priority_min(int policy) -{ - int ret = -EINVAL; - - switch (policy) { - case SCHED_FIFO: - case SCHED_RR: - ret = 1; - break; - case SCHED_NORMAL: - case SCHED_BATCH: - case SCHED_IDLE: - ret = 0; - } - 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. - */ -asmlinkage -long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) -{ - struct task_struct *p; - unsigned int time_slice; - int retval; - struct timespec t; - - if (pid < 0) - return -EINVAL; - - retval = -ESRCH; - read_lock(&tasklist_lock); - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; - - retval = security_task_getscheduler(p); - if (retval) - goto out_unlock; - - /* - * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER - * tasks that are on an otherwise idle runqueue: - */ - time_slice = 0; - if (p->policy == SCHED_RR) { - time_slice = DEF_TIMESLICE; - } else if (p->policy != SCHED_FIFO) { - struct sched_entity *se = &p->se; - unsigned long flags; - struct rq *rq; - - rq = task_rq_lock(p, &flags); - if (rq->cfs.load.weight) - time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); - task_rq_unlock(rq, &flags); - } - read_unlock(&tasklist_lock); - jiffies_to_timespec(time_slice, &t); - retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; - return retval; - -out_unlock: - read_unlock(&tasklist_lock); - return retval; -} - -static const char stat_nam[] = "RSDTtZX"; - -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 "%-13.13s %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 - { - unsigned long *n = end_of_stack(p); - while (!*n) - n++; - free = (unsigned long)n - (unsigned long)end_of_stack(p); - } -#endif - printk(KERN_CONT "%5lu %5d %6d\n", free, - task_pid_nr(p), task_pid_nr(p->real_parent)); - - 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 - read_lock(&tasklist_lock); - do_each_thread(g, p) { - /* - * reset the NMI-timeout, listing all files on a slow - * console might take alot 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(); - -#ifdef CONFIG_SCHED_DEBUG - sysrq_sched_debug_show(); -#endif - read_unlock(&tasklist_lock); - /* - * Only show locks if all tasks are dumped: - */ - if (state_filter == -1) - debug_show_all_locks(); -} - -void __cpuinit init_idle_bootup_task(struct task_struct *idle) -{ - idle->sched_class = &idle_sched_class; -} - -/** - * 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 __cpuinit init_idle(struct task_struct *idle, int cpu) -{ - struct rq *rq = cpu_rq(cpu); - unsigned long flags; - - __sched_fork(idle); - idle->se.exec_start = sched_clock(); - - idle->prio = idle->normal_prio = MAX_PRIO; - idle->cpus_allowed = cpumask_of_cpu(cpu); - __set_task_cpu(idle, cpu); - - spin_lock_irqsave(&rq->lock, flags); - rq->curr = rq->idle = idle; -#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) - idle->oncpu = 1; -#endif - spin_unlock_irqrestore(&rq->lock, flags); - - /* Set the preempt count _outside_ the spinlocks! */ - task_thread_info(idle)->preempt_count = 0; - - /* - * The idle tasks have their own, simple scheduling class: - */ - idle->sched_class = &idle_sched_class; -} - -/* - * In a system that switches off the HZ timer nohz_cpu_mask - * indicates which cpus entered this state. This is used - * in the rcu update to wait only for active cpus. For system - * which do not switch off the HZ timer nohz_cpu_mask should - * always be CPU_MASK_NONE. - */ -cpumask_t nohz_cpu_mask = CPU_MASK_NONE; - -/* - * Increase the granularity value when there are more CPUs, - * because with more CPUs the 'effective latency' as visible - * to users decreases. But the relationship is not linear, - * so pick a second-best guess by going with the log2 of the - * number of CPUs. - * - * This idea comes from the SD scheduler of Con Kolivas: - */ -static inline void sched_init_granularity(void) -{ - unsigned int factor = 1 + ilog2(num_online_cpus()); - const unsigned long limit = 200000000; - - sysctl_sched_min_granularity *= factor; - if (sysctl_sched_min_granularity > limit) - sysctl_sched_min_granularity = limit; - - sysctl_sched_latency *= factor; - if (sysctl_sched_latency > limit) - sysctl_sched_latency = limit; - - sysctl_sched_wakeup_granularity *= factor; - sysctl_sched_batch_wakeup_granularity *= factor; -} - -#ifdef CONFIG_SMP -/* - * This is how migration works: - * - * 1) we queue a struct migration_req structure in the source CPU's - * runqueue and wake up that CPU's migration thread. - * 2) we down() the locked semaphore => thread blocks. - * 3) migration thread wakes up (implicitly it forces the migrated - * thread off the CPU) - * 4) it gets the migration request and checks whether the migrated - * task is still in the wrong runqueue. - * 5) if it's in the wrong runqueue then the migration thread removes - * it and puts it into the right queue. - * 6) migration thread up()s the semaphore. - * 7) we wake up and the migration is done. - */ - -/* - * 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(struct task_struct *p, cpumask_t new_mask) -{ - struct migration_req req; - unsigned long flags; - struct rq *rq; - int ret = 0; - - rq = task_rq_lock(p, &flags); - if (!cpus_intersects(new_mask, cpu_online_map)) { - ret = -EINVAL; - goto out; - } - - if (p->sched_class->set_cpus_allowed) - p->sched_class->set_cpus_allowed(p, &new_mask); - else { - p->cpus_allowed = new_mask; - p->rt.nr_cpus_allowed = cpus_weight(new_mask); - } - - /* Can the task run on the task's current CPU? If so, we're done */ - if (cpu_isset(task_cpu(p), new_mask)) - goto out; - - if (migrate_task(p, any_online_cpu(new_mask), &req)) { - /* Need help from migration thread: drop lock and wait. */ - task_rq_unlock(rq, &flags); - wake_up_process(rq->migration_thread); - wait_for_completion(&req.done); - tlb_migrate_finish(p->mm); - return 0; - } -out: - task_rq_unlock(rq, &flags); - - return ret; -} -EXPORT_SYMBOL_GPL(set_cpus_allowed); - -/* - * Move (not current) task off this cpu, onto dest cpu. We're doing - * this because either it can't run here any more (set_cpus_allowed() - * away from this CPU, or CPU going down), or because we're - * attempting to rebalance this task on exec (sched_exec). - * - * So we race with normal scheduler movements, but that's OK, as long - * as the task is no longer on this CPU. - * - * Returns non-zero if task was successfully migrated. - */ -static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) -{ - struct rq *rq_dest, *rq_src; - int ret = 0, on_rq; - - if (unlikely(cpu_is_offline(dest_cpu))) - return ret; - - rq_src = cpu_rq(src_cpu); - rq_dest = cpu_rq(dest_cpu); - - double_rq_lock(rq_src, rq_dest); - /* Already moved. */ - if (task_cpu(p) != src_cpu) - goto out; - /* Affinity changed (again). */ - if (!cpu_isset(dest_cpu, p->cpus_allowed)) - goto out; - - on_rq = p->se.on_rq; - if (on_rq) - deactivate_task(rq_src, p, 0); - - set_task_cpu(p, dest_cpu); - if (on_rq) { - activate_task(rq_dest, p, 0); - check_preempt_curr(rq_dest, p); - } - ret = 1; -out: - double_rq_unlock(rq_src, rq_dest); - return ret; -} - -/* - * migration_thread - this is a highprio system thread that performs - * thread migration by bumping thread off CPU then 'pushing' onto - * another runqueue. - */ -static int migration_thread(void *data) -{ - int cpu = (long)data; - struct rq *rq; - - rq = cpu_rq(cpu); - BUG_ON(rq->migration_thread != current); - - set_current_state(TASK_INTERRUPTIBLE); - while (!kthread_should_stop()) { - struct migration_req *req; - struct list_head *head; - - spin_lock_irq(&rq->lock); - - if (cpu_is_offline(cpu)) { - spin_unlock_irq(&rq->lock); - goto wait_to_die; - } - - if (rq->active_balance) { - active_load_balance(rq, cpu); - rq->active_balance = 0; - } - - head = &rq->migration_queue; - - if (list_empty(head)) { - spin_unlock_irq(&rq->lock); - schedule(); - set_current_state(TASK_INTERRUPTIBLE); - continue; - } - req = list_entry(head->next, struct migration_req, list); - list_del_init(head->next); - - spin_unlock(&rq->lock); - __migrate_task(req->task, cpu, req->dest_cpu); - local_irq_enable(); - - complete(&req->done); - } - __set_current_state(TASK_RUNNING); - return 0; - -wait_to_die: - /* Wait for kthread_stop */ - set_current_state(TASK_INTERRUPTIBLE); - while (!kthread_should_stop()) { - schedule(); - set_current_state(TASK_INTERRUPTIBLE); - } - __set_current_state(TASK_RUNNING); - return 0; -} - -#ifdef CONFIG_HOTPLUG_CPU - -static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) -{ - int ret; - - local_irq_disable(); - ret = __migrate_task(p, src_cpu, dest_cpu); - local_irq_enable(); - return ret; -} - -/* - * Figure out where task on dead CPU should go, use force if necessary. - * NOTE: interrupts should be disabled by the caller - */ -static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) -{ - unsigned long flags; - cpumask_t mask; - struct rq *rq; - int dest_cpu; - - do { - /* On same node? */ - mask = node_to_cpumask(cpu_to_node(dead_cpu)); - cpus_and(mask, mask, p->cpus_allowed); - dest_cpu = any_online_cpu(mask); - - /* On any allowed CPU? */ - if (dest_cpu == NR_CPUS) - dest_cpu = any_online_cpu(p->cpus_allowed); - - /* No more Mr. Nice Guy. */ - if (dest_cpu == NR_CPUS) { - cpumask_t cpus_allowed = cpuset_cpus_allowed_locked(p); - /* - * Try to stay on the same cpuset, where the - * current cpuset may be a subset of all cpus. - * The cpuset_cpus_allowed_locked() variant of - * cpuset_cpus_allowed() will not block. It must be - * called within calls to cpuset_lock/cpuset_unlock. - */ - rq = task_rq_lock(p, &flags); - p->cpus_allowed = cpus_allowed; - dest_cpu = any_online_cpu(p->cpus_allowed); - task_rq_unlock(rq, &flags); - - /* - * 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, dead_cpu); - } - } - } while (!__migrate_task_irq(p, dead_cpu, dest_cpu)); -} - -/* - * While a dead CPU has no uninterruptible tasks queued at this point, - * it might still have a nonzero ->nr_uninterruptible counter, because - * for performance reasons the counter is not stricly tracking tasks to - * their home CPUs. So we just add the counter to another CPU's counter, - * to keep the global sum constant after CPU-down: - */ -static void migrate_nr_uninterruptible(struct rq *rq_src) -{ - struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); - unsigned long flags; - - local_irq_save(flags); - double_rq_lock(rq_src, rq_dest); - rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; - rq_src->nr_uninterruptible = 0; - double_rq_unlock(rq_src, rq_dest); - local_irq_restore(flags); -} - -/* Run through task list and migrate tasks from the dead cpu. */ -static void migrate_live_tasks(int src_cpu) -{ - struct task_struct *p, *t; - - read_lock(&tasklist_lock); - - do_each_thread(t, p) { - if (p == current) - continue; - - if (task_cpu(p) == src_cpu) - move_task_off_dead_cpu(src_cpu, p); - } while_each_thread(t, p); - - read_unlock(&tasklist_lock); -} - -/* - * 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(void) -{ - int this_cpu = smp_processor_id(); - struct rq *rq = cpu_rq(this_cpu); - struct task_struct *p = rq->idle; - unsigned long flags; - - /* cpu has to be offline */ - BUG_ON(cpu_online(this_cpu)); - - /* - * Strictly not necessary since rest of the CPUs are stopped by now - * and interrupts disabled on the current cpu. - */ - spin_lock_irqsave(&rq->lock, flags); - - __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); - - update_rq_clock(rq); - activate_task(rq, p, 0); - - spin_unlock_irqrestore(&rq->lock, flags); -} - -/* - * 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); -} - -/* called under rq->lock with disabled interrupts */ -static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) -{ - struct rq *rq = cpu_rq(dead_cpu); - - /* Must be exiting, otherwise would be on tasklist. */ - BUG_ON(!p->exit_state); - - /* Cannot have done final schedule yet: would have vanished. */ - BUG_ON(p->state == TASK_DEAD); - - get_task_struct(p); - - /* - * Drop lock around migration; if someone else moves it, - * that's OK. No task can be added to this CPU, so iteration is - * fine. - */ - spin_unlock_irq(&rq->lock); - move_task_off_dead_cpu(dead_cpu, p); - spin_lock_irq(&rq->lock); - - put_task_struct(p); -} - -/* release_task() removes task from tasklist, so we won't find dead tasks. */ -static void migrate_dead_tasks(unsigned int dead_cpu) -{ - struct rq *rq = cpu_rq(dead_cpu); - struct task_struct *next; - - for ( ; ; ) { - if (!rq->nr_running) - break; - update_rq_clock(rq); - next = pick_next_task(rq, rq->curr); - if (!next) - break; - migrate_dead(dead_cpu, next); - - } -} -#endif /* CONFIG_HOTPLUG_CPU */ - -#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) - -static struct ctl_table sd_ctl_dir[] = { - { - .procname = "sched_domain", - .mode = 0555, - }, - {0, }, -}; - -static struct ctl_table sd_ctl_root[] = { - { - .ctl_name = CTL_KERN, - .procname = "kernel", - .mode = 0555, - .child = sd_ctl_dir, - }, - {0, }, -}; - -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(12); - - 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); - /* &table[11] 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_online_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_online_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 - -/* - * migration_call - callback that gets triggered when a CPU is added. - * Here we can start up the necessary migration thread for the new CPU. - */ -static int __cpuinit -migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) -{ - struct task_struct *p; - int cpu = (long)hcpu; - unsigned long flags; - struct rq *rq; - - switch (action) { - - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); - if (IS_ERR(p)) - return NOTIFY_BAD; - kthread_bind(p, cpu); - /* Must be high prio: stop_machine expects to yield to it. */ - rq = task_rq_lock(p, &flags); - __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); - task_rq_unlock(rq, &flags); - cpu_rq(cpu)->migration_thread = p; - break; - - case CPU_ONLINE: - case CPU_ONLINE_FROZEN: - /* Strictly unnecessary, as first user will wake it. */ - wake_up_process(cpu_rq(cpu)->migration_thread); - - /* Update our root-domain */ - rq = cpu_rq(cpu); - spin_lock_irqsave(&rq->lock, flags); - if (rq->rd) { - BUG_ON(!cpu_isset(cpu, rq->rd->span)); - cpu_set(cpu, rq->rd->online); - } - spin_unlock_irqrestore(&rq->lock, flags); - break; - -#ifdef CONFIG_HOTPLUG_CPU - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - if (!cpu_rq(cpu)->migration_thread) - break; - /* Unbind it from offline cpu so it can run. Fall thru. */ - kthread_bind(cpu_rq(cpu)->migration_thread, - any_online_cpu(cpu_online_map)); - kthread_stop(cpu_rq(cpu)->migration_thread); - cpu_rq(cpu)->migration_thread = NULL; - break; - - case CPU_DEAD: - case CPU_DEAD_FROZEN: - cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ - migrate_live_tasks(cpu); - rq = cpu_rq(cpu); - kthread_stop(rq->migration_thread); - rq->migration_thread = NULL; - /* Idle task back to normal (off runqueue, low prio) */ - spin_lock_irq(&rq->lock); - update_rq_clock(rq); - deactivate_task(rq, rq->idle, 0); - rq->idle->static_prio = MAX_PRIO; - __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); - rq->idle->sched_class = &idle_sched_class; - migrate_dead_tasks(cpu); - spin_unlock_irq(&rq->lock); - cpuset_unlock(); - migrate_nr_uninterruptible(rq); - BUG_ON(rq->nr_running != 0); - - /* - * No need to migrate the tasks: it was best-effort if - * they didn't take sched_hotcpu_mutex. Just wake up - * the requestors. - */ - spin_lock_irq(&rq->lock); - while (!list_empty(&rq->migration_queue)) { - struct migration_req *req; - - req = list_entry(rq->migration_queue.next, - struct migration_req, list); - list_del_init(&req->list); - complete(&req->done); - } - spin_unlock_irq(&rq->lock); - break; - - case CPU_DYING: - case CPU_DYING_FROZEN: - /* Update our root-domain */ - rq = cpu_rq(cpu); - spin_lock_irqsave(&rq->lock, flags); - if (rq->rd) { - BUG_ON(!cpu_isset(cpu, rq->rd->span)); - cpu_clear(cpu, rq->rd->online); - } - spin_unlock_irqrestore(&rq->lock, flags); - break; -#endif - } - return NOTIFY_OK; -} - -/* Register at highest priority so that task migration (migrate_all_tasks) - * happens before everything else. - */ -static struct notifier_block __cpuinitdata migration_notifier = { - .notifier_call = migration_call, - .priority = 10 -}; - -void __init migration_init(void) -{ - void *cpu = (void *)(long)smp_processor_id(); - int err; - - /* Start one 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); -} -#endif - -#ifdef CONFIG_SMP - -/* Number of possible processor ids */ -int nr_cpu_ids __read_mostly = NR_CPUS; -EXPORT_SYMBOL(nr_cpu_ids); - -#ifdef CONFIG_SCHED_DEBUG - -static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level) -{ - struct sched_group *group = sd->groups; - cpumask_t groupmask; - char str[NR_CPUS]; - - cpumask_scnprintf(str, NR_CPUS, sd->span); - cpus_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\n", str); - - if (!cpu_isset(cpu, sd->span)) { - printk(KERN_ERR "ERROR: domain->span does not contain " - "CPU%d\n", cpu); - } - if (!cpu_isset(cpu, group->cpumask)) { - 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->__cpu_power) { - printk(KERN_CONT "\n"); - printk(KERN_ERR "ERROR: domain->cpu_power not " - "set\n"); - break; - } - - if (!cpus_weight(group->cpumask)) { - printk(KERN_CONT "\n"); - printk(KERN_ERR "ERROR: empty group\n"); - break; - } - - if (cpus_intersects(groupmask, group->cpumask)) { - printk(KERN_CONT "\n"); - printk(KERN_ERR "ERROR: repeated CPUs\n"); - break; - } - - cpus_or(groupmask, groupmask, group->cpumask); - - cpumask_scnprintf(str, NR_CPUS, group->cpumask); - printk(KERN_CONT " %s", str); - - group = group->next; - } while (group != sd->groups); - printk(KERN_CONT "\n"); - - if (!cpus_equal(sd->span, groupmask)) - printk(KERN_ERR "ERROR: groups don't span domain->span\n"); - - if (sd->parent && !cpus_subset(groupmask, sd->parent->span)) - 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 (!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)) - break; - level++; - sd = sd->parent; - if (!sd) - break; - } -} -#else -# define sched_domain_debug(sd, cpu) do { } while (0) -#endif - -static int sd_degenerate(struct sched_domain *sd) -{ - if (cpus_weight(sd->span) == 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_IDLE | - SD_WAKE_AFFINE | - SD_WAKE_BALANCE)) - 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 (!cpus_equal(sd->span, parent->span)) - return 0; - - /* Does parent contain flags not in child? */ - /* WAKE_BALANCE is a subset of WAKE_AFFINE */ - if (cflags & SD_WAKE_AFFINE) - pflags &= ~SD_WAKE_BALANCE; - /* 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 (~cflags & pflags) - return 0; - - return 1; -} - -static void rq_attach_root(struct rq *rq, struct root_domain *rd) -{ - unsigned long flags; - const struct sched_class *class; - - spin_lock_irqsave(&rq->lock, flags); - - if (rq->rd) { - struct root_domain *old_rd = rq->rd; - - for (class = sched_class_highest; class; class = class->next) { - if (class->leave_domain) - class->leave_domain(rq); - } - - cpu_clear(rq->cpu, old_rd->span); - cpu_clear(rq->cpu, old_rd->online); - - if (atomic_dec_and_test(&old_rd->refcount)) - kfree(old_rd); - } - - atomic_inc(&rd->refcount); - rq->rd = rd; - - cpu_set(rq->cpu, rd->span); - if (cpu_isset(rq->cpu, cpu_online_map)) - cpu_set(rq->cpu, rd->online); - - for (class = sched_class_highest; class; class = class->next) { - if (class->join_domain) - class->join_domain(rq); - } - - spin_unlock_irqrestore(&rq->lock, flags); -} - -static void init_rootdomain(struct root_domain *rd) -{ - memset(rd, 0, sizeof(*rd)); - - cpus_clear(rd->span); - cpus_clear(rd->online); -} - -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; - - init_rootdomain(rd); - - return rd; -} - -/* - * 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; tmp = tmp->parent) { - 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; - } - } - - if (sd && sd_degenerate(sd)) { - sd = sd->parent; - if (sd) - sd->child = NULL; - } - - sched_domain_debug(sd, cpu); - - rq_attach_root(rq, rd); - rcu_assign_pointer(rq->sd, sd); -} - -/* cpus with isolated domains */ -static cpumask_t cpu_isolated_map = CPU_MASK_NONE; - -/* Setup the mask of cpus configured for isolated domains */ -static int __init isolated_cpu_setup(char *str) -{ - int ints[NR_CPUS], i; - - str = get_options(str, ARRAY_SIZE(ints), ints); - cpus_clear(cpu_isolated_map); - for (i = 1; i <= ints[0]; i++) - if (ints[i] < NR_CPUS) - cpu_set(ints[i], cpu_isolated_map); - return 1; -} - -__setup("isolcpus=", isolated_cpu_setup); - -/* - * init_sched_build_groups takes the cpumask we wish to span, and a pointer - * to a function which identifies what group(along with sched group) a CPU - * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS - * (due to the fact that we keep track of groups covered with a cpumask_t). - * - * init_sched_build_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. - */ -static void -init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, - int (*group_fn)(int cpu, const cpumask_t *cpu_map, - struct sched_group **sg)) -{ - struct sched_group *first = NULL, *last = NULL; - cpumask_t covered = CPU_MASK_NONE; - int i; - - for_each_cpu_mask(i, span) { - struct sched_group *sg; - int group = group_fn(i, cpu_map, &sg); - int j; - - if (cpu_isset(i, covered)) - continue; - - sg->cpumask = CPU_MASK_NONE; - sg->__cpu_power = 0; - - for_each_cpu_mask(j, span) { - if (group_fn(j, cpu_map, NULL) != group) - continue; - - cpu_set(j, covered); - cpu_set(j, sg->cpumask); - } - if (!first) - first = sg; - if (last) - last->next = sg; - last = sg; - } - last->next = first; -} - -#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, unsigned long *used_nodes) -{ - int i, n, val, min_val, best_node = 0; - - min_val = INT_MAX; - - for (i = 0; i < MAX_NUMNODES; i++) { - /* Start at @node */ - n = (node + i) % MAX_NUMNODES; - - if (!nr_cpus_node(n)) - continue; - - /* Skip already used nodes */ - if (test_bit(n, used_nodes)) - continue; - - /* Simple min distance search */ - val = node_distance(node, n); - - if (val < min_val) { - min_val = val; - best_node = n; - } - } - - set_bit(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 - * @size: number of nodes to include in this span - * - * 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 cpumask_t sched_domain_node_span(int node) -{ - DECLARE_BITMAP(used_nodes, MAX_NUMNODES); - cpumask_t span, nodemask; - int i; - - cpus_clear(span); - bitmap_zero(used_nodes, MAX_NUMNODES); - - nodemask = node_to_cpumask(node); - cpus_or(span, span, nodemask); - set_bit(node, used_nodes); - - for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { - int next_node = find_next_best_node(node, used_nodes); - - nodemask = node_to_cpumask(next_node); - cpus_or(span, span, nodemask); - } - - return span; -} -#endif - -int sched_smt_power_savings = 0, sched_mc_power_savings = 0; - -/* - * SMT sched-domains: - */ -#ifdef CONFIG_SCHED_SMT -static DEFINE_PER_CPU(struct sched_domain, cpu_domains); -static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); - -static int -cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) -{ - if (sg) - *sg = &per_cpu(sched_group_cpus, cpu); - return cpu; -} -#endif - -/* - * multi-core sched-domains: - */ -#ifdef CONFIG_SCHED_MC -static DEFINE_PER_CPU(struct sched_domain, core_domains); -static DEFINE_PER_CPU(struct sched_group, sched_group_core); -#endif - -#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) -static int -cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) -{ - int group; - cpumask_t mask = per_cpu(cpu_sibling_map, cpu); - cpus_and(mask, mask, *cpu_map); - group = first_cpu(mask); - if (sg) - *sg = &per_cpu(sched_group_core, group); - return group; -} -#elif defined(CONFIG_SCHED_MC) -static int -cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) -{ - if (sg) - *sg = &per_cpu(sched_group_core, cpu); - return cpu; -} -#endif - -static DEFINE_PER_CPU(struct sched_domain, phys_domains); -static DEFINE_PER_CPU(struct sched_group, sched_group_phys); - -static int -cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg) -{ - int group; -#ifdef CONFIG_SCHED_MC - cpumask_t mask = cpu_coregroup_map(cpu); - cpus_and(mask, mask, *cpu_map); - group = first_cpu(mask); -#elif defined(CONFIG_SCHED_SMT) - cpumask_t mask = per_cpu(cpu_sibling_map, cpu); - cpus_and(mask, mask, *cpu_map); - group = first_cpu(mask); -#else - group = cpu; -#endif - if (sg) - *sg = &per_cpu(sched_group_phys, group); - return group; -} - -#ifdef CONFIG_NUMA -/* - * The init_sched_build_groups can't handle what we want to do with node - * groups, so roll our own. Now each node has its own list of groups which - * gets dynamically allocated. - */ -static DEFINE_PER_CPU(struct sched_domain, node_domains); -static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; - -static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); -static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); - -static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, - struct sched_group **sg) -{ - cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); - int group; - - cpus_and(nodemask, nodemask, *cpu_map); - group = first_cpu(nodemask); - - if (sg) - *sg = &per_cpu(sched_group_allnodes, group); - return group; -} - -static void init_numa_sched_groups_power(struct sched_group *group_head) -{ - struct sched_group *sg = group_head; - int j; - - if (!sg) - return; - do { - for_each_cpu_mask(j, sg->cpumask) { - struct sched_domain *sd; - - sd = &per_cpu(phys_domains, j); - if (j != first_cpu(sd->groups->cpumask)) { - /* - * Only add "power" once for each - * physical package. - */ - continue; - } - - sg_inc_cpu_power(sg, sd->groups->__cpu_power); - } - sg = sg->next; - } while (sg != group_head); -} -#endif - -#ifdef CONFIG_NUMA -/* Free memory allocated for various sched_group structures */ -static void free_sched_groups(const cpumask_t *cpu_map) -{ - int cpu, i; - - for_each_cpu_mask(cpu, *cpu_map) { - struct sched_group **sched_group_nodes - = sched_group_nodes_bycpu[cpu]; - - if (!sched_group_nodes) - continue; - - for (i = 0; i < MAX_NUMNODES; i++) { - cpumask_t nodemask = node_to_cpumask(i); - struct sched_group *oldsg, *sg = sched_group_nodes[i]; - - cpus_and(nodemask, nodemask, *cpu_map); - if (cpus_empty(nodemask)) - continue; - - if (sg == NULL) - continue; - sg = sg->next; -next_sg: - oldsg = sg; - sg = sg->next; - kfree(oldsg); - if (oldsg != sched_group_nodes[i]) - goto next_sg; - } - kfree(sched_group_nodes); - sched_group_nodes_bycpu[cpu] = NULL; - } -} -#else -static void free_sched_groups(const cpumask_t *cpu_map) -{ -} -#endif - -/* - * Initialize sched groups cpu_power. - * - * cpu_power indicates the capacity of sched group, which is used while - * distributing the load between different sched groups in a sched domain. - * Typically cpu_power for all the groups in a sched domain will be same unless - * there are asymmetries in the topology. If there are asymmetries, group - * having more cpu_power will pickup more load compared to the group having - * less cpu_power. - * - * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents - * the maximum number of tasks a group can handle in the presence of other idle - * or lightly loaded groups in the same sched domain. - */ -static void init_sched_groups_power(int cpu, struct sched_domain *sd) -{ - struct sched_domain *child; - struct sched_group *group; - - WARN_ON(!sd || !sd->groups); - - if (cpu != first_cpu(sd->groups->cpumask)) - return; - - child = sd->child; - - sd->groups->__cpu_power = 0; - - /* - * For perf policy, if the groups in child domain share resources - * (for example cores sharing some portions of the cache hierarchy - * or SMT), then set this domain groups cpu_power such that each group - * can handle only one task, when there are other idle groups in the - * same sched domain. - */ - if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && - (child->flags & - (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { - sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); - return; - } - - /* - * add cpu_power of each child group to this groups cpu_power - */ - group = child->groups; - do { - sg_inc_cpu_power(sd->groups, group->__cpu_power); - group = group->next; - } while (group != child->groups); -} - -/* - * Build sched domains for a given set of cpus and attach the sched domains - * to the individual cpus - */ -static int build_sched_domains(const cpumask_t *cpu_map) -{ - int i; - struct root_domain *rd; -#ifdef CONFIG_NUMA - struct sched_group **sched_group_nodes = NULL; - int sd_allnodes = 0; - - /* - * Allocate the per-node list of sched groups - */ - sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *), - GFP_KERNEL); - if (!sched_group_nodes) { - printk(KERN_WARNING "Can not alloc sched group node list\n"); - return -ENOMEM; - } - sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; -#endif - - rd = alloc_rootdomain(); - if (!rd) { - printk(KERN_WARNING "Cannot alloc root domain\n"); - return -ENOMEM; - } - - /* - * Set up domains for cpus specified by the cpu_map. - */ - for_each_cpu_mask(i, *cpu_map) { - struct sched_domain *sd = NULL, *p; - cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); - - cpus_and(nodemask, nodemask, *cpu_map); - -#ifdef CONFIG_NUMA - if (cpus_weight(*cpu_map) > - SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { - sd = &per_cpu(allnodes_domains, i); - *sd = SD_ALLNODES_INIT; - sd->span = *cpu_map; - cpu_to_allnodes_group(i, cpu_map, &sd->groups); - p = sd; - sd_allnodes = 1; - } else - p = NULL; - - sd = &per_cpu(node_domains, i); - *sd = SD_NODE_INIT; - sd->span = sched_domain_node_span(cpu_to_node(i)); - sd->parent = p; - if (p) - p->child = sd; - cpus_and(sd->span, sd->span, *cpu_map); -#endif - - p = sd; - sd = &per_cpu(phys_domains, i); - *sd = SD_CPU_INIT; - sd->span = nodemask; - sd->parent = p; - if (p) - p->child = sd; - cpu_to_phys_group(i, cpu_map, &sd->groups); - -#ifdef CONFIG_SCHED_MC - p = sd; - sd = &per_cpu(core_domains, i); - *sd = SD_MC_INIT; - sd->span = cpu_coregroup_map(i); - cpus_and(sd->span, sd->span, *cpu_map); - sd->parent = p; - p->child = sd; - cpu_to_core_group(i, cpu_map, &sd->groups); -#endif - -#ifdef CONFIG_SCHED_SMT - p = sd; - sd = &per_cpu(cpu_domains, i); - *sd = SD_SIBLING_INIT; - sd->span = per_cpu(cpu_sibling_map, i); - cpus_and(sd->span, sd->span, *cpu_map); - sd->parent = p; - p->child = sd; - cpu_to_cpu_group(i, cpu_map, &sd->groups); -#endif - } - -#ifdef CONFIG_SCHED_SMT - /* Set up CPU (sibling) groups */ - for_each_cpu_mask(i, *cpu_map) { - cpumask_t this_sibling_map = per_cpu(cpu_sibling_map, i); - cpus_and(this_sibling_map, this_sibling_map, *cpu_map); - if (i != first_cpu(this_sibling_map)) - continue; - - init_sched_build_groups(this_sibling_map, cpu_map, - &cpu_to_cpu_group); - } -#endif - -#ifdef CONFIG_SCHED_MC - /* Set up multi-core groups */ - for_each_cpu_mask(i, *cpu_map) { - cpumask_t this_core_map = cpu_coregroup_map(i); - cpus_and(this_core_map, this_core_map, *cpu_map); - if (i != first_cpu(this_core_map)) - continue; - init_sched_build_groups(this_core_map, cpu_map, - &cpu_to_core_group); - } -#endif - - /* Set up physical groups */ - for (i = 0; i < MAX_NUMNODES; i++) { - cpumask_t nodemask = node_to_cpumask(i); - - cpus_and(nodemask, nodemask, *cpu_map); - if (cpus_empty(nodemask)) - continue; - - init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); - } - -#ifdef CONFIG_NUMA - /* Set up node groups */ - if (sd_allnodes) - init_sched_build_groups(*cpu_map, cpu_map, - &cpu_to_allnodes_group); - - for (i = 0; i < MAX_NUMNODES; i++) { - /* Set up node groups */ - struct sched_group *sg, *prev; - cpumask_t nodemask = node_to_cpumask(i); - cpumask_t domainspan; - cpumask_t covered = CPU_MASK_NONE; - int j; - - cpus_and(nodemask, nodemask, *cpu_map); - if (cpus_empty(nodemask)) { - sched_group_nodes[i] = NULL; - continue; - } - - domainspan = sched_domain_node_span(i); - cpus_and(domainspan, domainspan, *cpu_map); - - sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); - if (!sg) { - printk(KERN_WARNING "Can not alloc domain group for " - "node %d\n", i); - goto error; - } - sched_group_nodes[i] = sg; - for_each_cpu_mask(j, nodemask) { - struct sched_domain *sd; - - sd = &per_cpu(node_domains, j); - sd->groups = sg; - } - sg->__cpu_power = 0; - sg->cpumask = nodemask; - sg->next = sg; - cpus_or(covered, covered, nodemask); - prev = sg; - - for (j = 0; j < MAX_NUMNODES; j++) { - cpumask_t tmp, notcovered; - int n = (i + j) % MAX_NUMNODES; - - cpus_complement(notcovered, covered); - cpus_and(tmp, notcovered, *cpu_map); - cpus_and(tmp, tmp, domainspan); - if (cpus_empty(tmp)) - break; - - nodemask = node_to_cpumask(n); - cpus_and(tmp, tmp, nodemask); - if (cpus_empty(tmp)) - continue; - - sg = kmalloc_node(sizeof(struct sched_group), - GFP_KERNEL, i); - if (!sg) { - printk(KERN_WARNING - "Can not alloc domain group for node %d\n", j); - goto error; - } - sg->__cpu_power = 0; - sg->cpumask = tmp; - sg->next = prev->next; - cpus_or(covered, covered, tmp); - prev->next = sg; - prev = sg; - } - } -#endif - - /* Calculate CPU power for physical packages and nodes */ -#ifdef CONFIG_SCHED_SMT - for_each_cpu_mask(i, *cpu_map) { - struct sched_domain *sd = &per_cpu(cpu_domains, i); - - init_sched_groups_power(i, sd); - } -#endif -#ifdef CONFIG_SCHED_MC - for_each_cpu_mask(i, *cpu_map) { - struct sched_domain *sd = &per_cpu(core_domains, i); - - init_sched_groups_power(i, sd); - } -#endif - - for_each_cpu_mask(i, *cpu_map) { - struct sched_domain *sd = &per_cpu(phys_domains, i); - - init_sched_groups_power(i, sd); - } - -#ifdef CONFIG_NUMA - for (i = 0; i < MAX_NUMNODES; i++) - init_numa_sched_groups_power(sched_group_nodes[i]); - - if (sd_allnodes) { - struct sched_group *sg; - - cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); - init_numa_sched_groups_power(sg); - } -#endif - - /* Attach the domains */ - for_each_cpu_mask(i, *cpu_map) { - struct sched_domain *sd; -#ifdef CONFIG_SCHED_SMT - sd = &per_cpu(cpu_domains, i); -#elif defined(CONFIG_SCHED_MC) - sd = &per_cpu(core_domains, i); -#else - sd = &per_cpu(phys_domains, i); -#endif - cpu_attach_domain(sd, rd, i); - } - - return 0; - -#ifdef CONFIG_NUMA -error: - free_sched_groups(cpu_map); - return -ENOMEM; -#endif -} - -static cpumask_t *doms_cur; /* current sched domains */ -static int ndoms_cur; /* number of sched domains in 'doms_cur' */ - -/* - * Special case: If a kmalloc of a doms_cur partition (array of - * cpumask_t) fails, then fallback to a single sched domain, - * as determined by the single cpumask_t fallback_doms. - */ -static cpumask_t fallback_doms; - -void __attribute__((weak)) arch_update_cpu_topology(void) -{ -} - -/* - * 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 arch_init_sched_domains(const cpumask_t *cpu_map) -{ - int err; - - arch_update_cpu_topology(); - ndoms_cur = 1; - doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL); - if (!doms_cur) - doms_cur = &fallback_doms; - cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map); - err = build_sched_domains(doms_cur); - register_sched_domain_sysctl(); - - return err; -} - -static void arch_destroy_sched_domains(const cpumask_t *cpu_map) -{ - free_sched_groups(cpu_map); -} - -/* - * 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 cpumask_t *cpu_map) -{ - int i; - - unregister_sched_domain_sysctl(); - - for_each_cpu_mask(i, *cpu_map) - cpu_attach_domain(NULL, &def_root_domain, i); - synchronize_sched(); - arch_destroy_sched_domains(cpu_map); -} - -/* - * 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_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 kmalloc'd. This routine takes - * ownership of it and will kfree it when done with it. If the caller - * failed the kmalloc call, then it can pass in doms_new == NULL, - * and partition_sched_domains() will fallback to the single partition - * 'fallback_doms'. - * - * Call with hotplug lock held - */ -void partition_sched_domains(int ndoms_new, cpumask_t *doms_new) -{ - int i, j; - - lock_doms_cur(); - - /* always unregister in case we don't destroy any domains */ - unregister_sched_domain_sysctl(); - - if (doms_new == NULL) { - ndoms_new = 1; - doms_new = &fallback_doms; - cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map); - } - - /* Destroy deleted domains */ - for (i = 0; i < ndoms_cur; i++) { - for (j = 0; j < ndoms_new; j++) { - if (cpus_equal(doms_cur[i], doms_new[j])) - goto match1; - } - /* no match - a current sched domain not in new doms_new[] */ - detach_destroy_domains(doms_cur + i); -match1: - ; - } - - /* Build new domains */ - for (i = 0; i < ndoms_new; i++) { - for (j = 0; j < ndoms_cur; j++) { - if (cpus_equal(doms_new[i], doms_cur[j])) - goto match2; - } - /* no match - add a new doms_new */ - build_sched_domains(doms_new + i); -match2: - ; - } - - /* Remember the new sched domains */ - if (doms_cur != &fallback_doms) - kfree(doms_cur); - doms_cur = doms_new; - ndoms_cur = ndoms_new; - - register_sched_domain_sysctl(); - - unlock_doms_cur(); -} - -#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) -int arch_reinit_sched_domains(void) -{ - int err; - - get_online_cpus(); - detach_destroy_domains(&cpu_online_map); - err = arch_init_sched_domains(&cpu_online_map); - put_online_cpus(); - - return err; -} - -static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) -{ - int ret; - - if (buf[0] != '0' && buf[0] != '1') - return -EINVAL; - - if (smt) - sched_smt_power_savings = (buf[0] == '1'); - else - sched_mc_power_savings = (buf[0] == '1'); - - ret = arch_reinit_sched_domains(); - - return ret ? ret : count; -} - -#ifdef CONFIG_SCHED_MC -static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) -{ - return sprintf(page, "%u\n", sched_mc_power_savings); -} -static ssize_t sched_mc_power_savings_store(struct sys_device *dev, - const char *buf, size_t count) -{ - return sched_power_savings_store(buf, count, 0); -} -static SYSDEV_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 sys_device *dev, char *page) -{ - return sprintf(page, "%u\n", sched_smt_power_savings); -} -static ssize_t sched_smt_power_savings_store(struct sys_device *dev, - const char *buf, size_t count) -{ - return sched_power_savings_store(buf, count, 1); -} -static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, - sched_smt_power_savings_store); -#endif - -int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) -{ - int err = 0; - -#ifdef CONFIG_SCHED_SMT - if (smt_capable()) - err = sysfs_create_file(&cls->kset.kobj, - &attr_sched_smt_power_savings.attr); -#endif -#ifdef CONFIG_SCHED_MC - if (!err && mc_capable()) - err = sysfs_create_file(&cls->kset.kobj, - &attr_sched_mc_power_savings.attr); -#endif - return err; -} -#endif - -/* - * Force a reinitialization of the sched domains hierarchy. The domains - * and groups cannot be updated in place without racing with the balancing - * code, so we temporarily attach all running cpus to the NULL domain - * which will prevent rebalancing while the sched domains are recalculated. - */ -static int update_sched_domains(struct notifier_block *nfb, - unsigned long action, void *hcpu) -{ - switch (action) { - case CPU_UP_PREPARE: - case CPU_UP_PREPARE_FROZEN: - case CPU_DOWN_PREPARE: - case CPU_DOWN_PREPARE_FROZEN: - detach_destroy_domains(&cpu_online_map); - return NOTIFY_OK; - - case CPU_UP_CANCELED: - case CPU_UP_CANCELED_FROZEN: - case CPU_DOWN_FAILED: - case CPU_DOWN_FAILED_FROZEN: - case CPU_ONLINE: - case CPU_ONLINE_FROZEN: - case CPU_DEAD: - case CPU_DEAD_FROZEN: - /* - * Fall through and re-initialise the domains. - */ - break; - default: - return NOTIFY_DONE; - } - - /* The hotplug lock is already held by cpu_up/cpu_down */ - arch_init_sched_domains(&cpu_online_map); - - return NOTIFY_OK; -} - -void __init sched_init_smp(void) -{ - cpumask_t non_isolated_cpus; - - get_online_cpus(); - arch_init_sched_domains(&cpu_online_map); - cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); - if (cpus_empty(non_isolated_cpus)) - cpu_set(smp_processor_id(), non_isolated_cpus); - put_online_cpus(); - /* XXX: Theoretical race here - CPU may be hotplugged now */ - hotcpu_notifier(update_sched_domains, 0); - - /* Move init over to a non-isolated CPU */ - if (set_cpus_allowed(current, non_isolated_cpus) < 0) - BUG(); - sched_init_granularity(); -} -#else -void __init sched_init_smp(void) -{ - sched_init_granularity(); -} -#endif /* CONFIG_SMP */ - -int in_sched_functions(unsigned long addr) -{ - return in_lock_functions(addr) || - (addr >= (unsigned long)__sched_text_start - && addr < (unsigned long)__sched_text_end); -} - -static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) -{ - cfs_rq->tasks_timeline = RB_ROOT; -#ifdef CONFIG_FAIR_GROUP_SCHED - cfs_rq->rq = rq; -#endif - cfs_rq->min_vruntime = (u64)(-(1LL << 20)); -} - -static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) -{ - struct rt_prio_array *array; - int i; - - array = &rt_rq->active; - for (i = 0; i < MAX_RT_PRIO; i++) { - INIT_LIST_HEAD(array->queue + i); - __clear_bit(i, array->bitmap); - } - /* delimiter for bitsearch: */ - __set_bit(MAX_RT_PRIO, array->bitmap); - -#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED - rt_rq->highest_prio = MAX_RT_PRIO; -#endif -#ifdef CONFIG_SMP - rt_rq->rt_nr_migratory = 0; - rt_rq->overloaded = 0; -#endif - - rt_rq->rt_time = 0; - rt_rq->rt_throttled = 0; - -#ifdef CONFIG_RT_GROUP_SCHED - rt_rq->rt_nr_boosted = 0; - rt_rq->rq = rq; -#endif -} - -#ifdef CONFIG_FAIR_GROUP_SCHED -static void init_tg_cfs_entry(struct rq *rq, struct task_group *tg, - struct cfs_rq *cfs_rq, struct sched_entity *se, - int cpu, int add) -{ - tg->cfs_rq[cpu] = cfs_rq; - init_cfs_rq(cfs_rq, rq); - cfs_rq->tg = tg; - if (add) - list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); - - tg->se[cpu] = se; - se->cfs_rq = &rq->cfs; - se->my_q = cfs_rq; - se->load.weight = tg->shares; - se->load.inv_weight = div64_64(1ULL<<32, se->load.weight); - se->parent = NULL; -} -#endif - -#ifdef CONFIG_RT_GROUP_SCHED -static void init_tg_rt_entry(struct rq *rq, struct task_group *tg, - struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, - int cpu, int add) -{ - tg->rt_rq[cpu] = rt_rq; - init_rt_rq(rt_rq, rq); - rt_rq->tg = tg; - rt_rq->rt_se = rt_se; - if (add) - list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); - - tg->rt_se[cpu] = rt_se; - rt_se->rt_rq = &rq->rt; - rt_se->my_q = rt_rq; - rt_se->parent = NULL; - INIT_LIST_HEAD(&rt_se->run_list); -} -#endif - -void __init sched_init(void) -{ - int highest_cpu = 0; - int i, j; - -#ifdef CONFIG_SMP - init_defrootdomain(); -#endif - -#ifdef CONFIG_GROUP_SCHED - list_add(&init_task_group.list, &task_groups); -#endif - - for_each_possible_cpu(i) { - struct rq *rq; - - rq = cpu_rq(i); - spin_lock_init(&rq->lock); - lockdep_set_class(&rq->lock, &rq->rq_lock_key); - rq->nr_running = 0; - rq->clock = 1; - init_cfs_rq(&rq->cfs, rq); - init_rt_rq(&rq->rt, rq); -#ifdef CONFIG_FAIR_GROUP_SCHED - init_task_group.shares = init_task_group_load; - INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); - init_tg_cfs_entry(rq, &init_task_group, - &per_cpu(init_cfs_rq, i), - &per_cpu(init_sched_entity, i), i, 1); - -#endif -#ifdef CONFIG_RT_GROUP_SCHED - init_task_group.rt_runtime = - sysctl_sched_rt_runtime * NSEC_PER_USEC; - INIT_LIST_HEAD(&rq->leaf_rt_rq_list); - init_tg_rt_entry(rq, &init_task_group, - &per_cpu(init_rt_rq, i), - &per_cpu(init_sched_rt_entity, i), i, 1); -#endif - rq->rt_period_expire = 0; - rq->rt_throttled = 0; - - for (j = 0; j < CPU_LOAD_IDX_MAX; j++) - rq->cpu_load[j] = 0; -#ifdef CONFIG_SMP - rq->sd = NULL; - rq->rd = NULL; - rq->active_balance = 0; - rq->next_balance = jiffies; - rq->push_cpu = 0; - rq->cpu = i; - rq->migration_thread = NULL; - INIT_LIST_HEAD(&rq->migration_queue); - rq_attach_root(rq, &def_root_domain); -#endif - init_rq_hrtick(rq); - atomic_set(&rq->nr_iowait, 0); - highest_cpu = i; - } - - set_load_weight(&init_task); - -#ifdef CONFIG_PREEMPT_NOTIFIERS - INIT_HLIST_HEAD(&init_task.preempt_notifiers); -#endif - -#ifdef CONFIG_SMP - nr_cpu_ids = highest_cpu + 1; - open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); -#endif - -#ifdef CONFIG_RT_MUTEXES - plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); -#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()); - /* - * During early bootup we pretend to be a normal task: - */ - current->sched_class = &fair_sched_class; - - scheduler_running = 1; -} - -#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP -void __might_sleep(char *file, int line) -{ -#ifdef in_atomic - static unsigned long prev_jiffy; /* ratelimiting */ - - if ((in_atomic() || irqs_disabled()) && - system_state == SYSTEM_RUNNING && !oops_in_progress) { - 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("in_atomic():%d, irqs_disabled():%d\n", - in_atomic(), irqs_disabled()); - debug_show_held_locks(current); - if (irqs_disabled()) - print_irqtrace_events(current); - dump_stack(); - } -#endif -} -EXPORT_SYMBOL(__might_sleep); -#endif - -#ifdef CONFIG_MAGIC_SYSRQ -static void normalize_task(struct rq *rq, struct task_struct *p) -{ - int on_rq; - update_rq_clock(rq); - on_rq = p->se.on_rq; - if (on_rq) - deactivate_task(rq, p, 0); - __setscheduler(rq, p, SCHED_NORMAL, 0); - if (on_rq) { - activate_task(rq, p, 0); - resched_task(rq->curr); - } -} - -void normalize_rt_tasks(void) -{ - struct task_struct *g, *p; - unsigned long flags; - struct rq *rq; - - read_lock_irqsave(&tasklist_lock, flags); - do_each_thread(g, p) { - /* - * Only normalize user tasks: - */ - if (!p->mm) - continue; - - p->se.exec_start = 0; -#ifdef CONFIG_SCHEDSTATS - p->se.wait_start = 0; - p->se.sleep_start = 0; - p->se.block_start = 0; -#endif - task_rq(p)->clock = 0; - - if (!rt_task(p)) { - /* - * Renice negative nice level userspace - * tasks back to 0: - */ - if (TASK_NICE(p) < 0 && p->mm) - set_user_nice(p, 0); - continue; - } - - spin_lock(&p->pi_lock); - rq = __task_rq_lock(p); - - normalize_task(rq, p); - - __task_rq_unlock(rq); - spin_unlock(&p->pi_lock); - } while_each_thread(g, p); - - read_unlock_irqrestore(&tasklist_lock, flags); -} - -#endif /* CONFIG_MAGIC_SYSRQ */ - -#ifdef CONFIG_IA64 -/* - * These functions are only useful for the IA64 MCA handling. - * - * 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); -} - -/** - * 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 synchronized, 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 - -#ifdef CONFIG_GROUP_SCHED - -#ifdef CONFIG_FAIR_GROUP_SCHED -static void free_fair_sched_group(struct task_group *tg) -{ - int i; - - for_each_possible_cpu(i) { - if (tg->cfs_rq) - kfree(tg->cfs_rq[i]); - if (tg->se) - kfree(tg->se[i]); - } - - kfree(tg->cfs_rq); - kfree(tg->se); -} - -static int alloc_fair_sched_group(struct task_group *tg) -{ - struct cfs_rq *cfs_rq; - struct sched_entity *se; - struct rq *rq; - int i; - - tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL); - if (!tg->cfs_rq) - goto err; - tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL); - if (!tg->se) - goto err; - - tg->shares = NICE_0_LOAD; - - for_each_possible_cpu(i) { - rq = cpu_rq(i); - - cfs_rq = kmalloc_node(sizeof(struct cfs_rq), - GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); - if (!cfs_rq) - goto err; - - se = kmalloc_node(sizeof(struct sched_entity), - GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); - if (!se) - goto err; - - init_tg_cfs_entry(rq, tg, cfs_rq, se, i, 0); - } - - return 1; - - err: - return 0; -} - -static inline void register_fair_sched_group(struct task_group *tg, int cpu) -{ - list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list, - &cpu_rq(cpu)->leaf_cfs_rq_list); -} - -static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) -{ - list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list); -} -#else -static inline void free_fair_sched_group(struct task_group *tg) -{ -} - -static inline int alloc_fair_sched_group(struct task_group *tg) -{ - return 1; -} - -static inline void register_fair_sched_group(struct task_group *tg, int cpu) -{ -} - -static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) -{ -} -#endif - -#ifdef CONFIG_RT_GROUP_SCHED -static void free_rt_sched_group(struct task_group *tg) -{ - int i; - - for_each_possible_cpu(i) { - if (tg->rt_rq) - kfree(tg->rt_rq[i]); - if (tg->rt_se) - kfree(tg->rt_se[i]); - } - - kfree(tg->rt_rq); - kfree(tg->rt_se); -} - -static int alloc_rt_sched_group(struct task_group *tg) -{ - struct rt_rq *rt_rq; - struct sched_rt_entity *rt_se; - struct rq *rq; - int i; - - tg->rt_rq = kzalloc(sizeof(rt_rq) * NR_CPUS, GFP_KERNEL); - if (!tg->rt_rq) - goto err; - tg->rt_se = kzalloc(sizeof(rt_se) * NR_CPUS, GFP_KERNEL); - if (!tg->rt_se) - goto err; - - tg->rt_runtime = 0; - - for_each_possible_cpu(i) { - rq = cpu_rq(i); - - rt_rq = kmalloc_node(sizeof(struct rt_rq), - GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); - if (!rt_rq) - goto err; - - rt_se = kmalloc_node(sizeof(struct sched_rt_entity), - GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); - if (!rt_se) - goto err; - - init_tg_rt_entry(rq, tg, rt_rq, rt_se, i, 0); - } - - return 1; - - err: - return 0; -} - -static inline void register_rt_sched_group(struct task_group *tg, int cpu) -{ - list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list, - &cpu_rq(cpu)->leaf_rt_rq_list); -} - -static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) -{ - list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list); -} -#else -static inline void free_rt_sched_group(struct task_group *tg) -{ -} - -static inline int alloc_rt_sched_group(struct task_group *tg) -{ - return 1; -} - -static inline void register_rt_sched_group(struct task_group *tg, int cpu) -{ -} - -static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) -{ -} -#endif - -static void free_sched_group(struct task_group *tg) -{ - free_fair_sched_group(tg); - free_rt_sched_group(tg); - kfree(tg); -} - -/* allocate runqueue etc for a new task group */ -struct task_group *sched_create_group(void) -{ - struct task_group *tg; - unsigned long flags; - int i; - - tg = kzalloc(sizeof(*tg), GFP_KERNEL); - if (!tg) - return ERR_PTR(-ENOMEM); - - if (!alloc_fair_sched_group(tg)) - goto err; - - if (!alloc_rt_sched_group(tg)) - goto err; - - spin_lock_irqsave(&task_group_lock, flags); - for_each_possible_cpu(i) { - register_fair_sched_group(tg, i); - register_rt_sched_group(tg, i); - } - list_add_rcu(&tg->list, &task_groups); - spin_unlock_irqrestore(&task_group_lock, flags); - - return tg; - -err: - free_sched_group(tg); - return ERR_PTR(-ENOMEM); -} - -/* rcu callback to free various structures associated with a task group */ -static void free_sched_group_rcu(struct rcu_head *rhp) -{ - /* now it should be safe to free those cfs_rqs */ - free_sched_group(container_of(rhp, struct task_group, rcu)); -} - -/* Destroy runqueue etc associated with a task group */ -void sched_destroy_group(struct task_group *tg) -{ - unsigned long flags; - int i; - - spin_lock_irqsave(&task_group_lock, flags); - for_each_possible_cpu(i) { - unregister_fair_sched_group(tg, i); - unregister_rt_sched_group(tg, i); - } - list_del_rcu(&tg->list); - spin_unlock_irqrestore(&task_group_lock, flags); - - /* wait for possible concurrent references to cfs_rqs complete */ - call_rcu(&tg->rcu, free_sched_group_rcu); -} - -/* change task's runqueue when it moves between groups. - * The caller of this function should have put the task in its new group - * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to - * reflect its new group. - */ -void sched_move_task(struct task_struct *tsk) -{ - int on_rq, running; - unsigned long flags; - struct rq *rq; - - rq = task_rq_lock(tsk, &flags); - - update_rq_clock(rq); - - running = task_current(rq, tsk); - on_rq = tsk->se.on_rq; - - if (on_rq) - dequeue_task(rq, tsk, 0); - if (unlikely(running)) - tsk->sched_class->put_prev_task(rq, tsk); - - set_task_rq(tsk, task_cpu(tsk)); - -#ifdef CONFIG_FAIR_GROUP_SCHED - if (tsk->sched_class->moved_group) - tsk->sched_class->moved_group(tsk); -#endif - - if (unlikely(running)) - tsk->sched_class->set_curr_task(rq); - if (on_rq) - enqueue_task(rq, tsk, 0); - - task_rq_unlock(rq, &flags); -} - -#ifdef CONFIG_FAIR_GROUP_SCHED -static void set_se_shares(struct sched_entity *se, unsigned long shares) -{ - struct cfs_rq *cfs_rq = se->cfs_rq; - struct rq *rq = cfs_rq->rq; - int on_rq; - - spin_lock_irq(&rq->lock); - - on_rq = se->on_rq; - if (on_rq) - dequeue_entity(cfs_rq, se, 0); - - se->load.weight = shares; - se->load.inv_weight = div64_64((1ULL<<32), shares); - - if (on_rq) - enqueue_entity(cfs_rq, se, 0); - - spin_unlock_irq(&rq->lock); -} - -static DEFINE_MUTEX(shares_mutex); - -int sched_group_set_shares(struct task_group *tg, unsigned long shares) -{ - int i; - unsigned long flags; - - /* - * A weight of 0 or 1 can cause arithmetics problems. - * (The default weight is 1024 - so there's no practical - * limitation from this.) - */ - if (shares < 2) - shares = 2; - - mutex_lock(&shares_mutex); - if (tg->shares == shares) - goto done; - - spin_lock_irqsave(&task_group_lock, flags); - for_each_possible_cpu(i) - unregister_fair_sched_group(tg, i); - spin_unlock_irqrestore(&task_group_lock, flags); - - /* wait for any ongoing reference to this group to finish */ - synchronize_sched(); - - /* - * Now we are free to modify the group's share on each cpu - * w/o tripping rebalance_share or load_balance_fair. - */ - tg->shares = shares; - for_each_possible_cpu(i) - set_se_shares(tg->se[i], shares); - - /* - * Enable load balance activity on this group, by inserting it back on - * each cpu's rq->leaf_cfs_rq_list. - */ - spin_lock_irqsave(&task_group_lock, flags); - for_each_possible_cpu(i) - register_fair_sched_group(tg, i); - spin_unlock_irqrestore(&task_group_lock, flags); -done: - mutex_unlock(&shares_mutex); - return 0; -} - -unsigned long sched_group_shares(struct task_group *tg) -{ - return tg->shares; -} -#endif - -#ifdef CONFIG_RT_GROUP_SCHED -/* - * Ensure that the real time constraints are schedulable. - */ -static DEFINE_MUTEX(rt_constraints_mutex); - -static unsigned long to_ratio(u64 period, u64 runtime) -{ - if (runtime == RUNTIME_INF) - return 1ULL << 16; - - return div64_64(runtime << 16, period); -} - -static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) -{ - struct task_group *tgi; - unsigned long total = 0; - unsigned long global_ratio = - to_ratio(sysctl_sched_rt_period, - sysctl_sched_rt_runtime < 0 ? - RUNTIME_INF : sysctl_sched_rt_runtime); - - rcu_read_lock(); - list_for_each_entry_rcu(tgi, &task_groups, list) { - if (tgi == tg) - continue; - - total += to_ratio(period, tgi->rt_runtime); - } - rcu_read_unlock(); - - return total + to_ratio(period, runtime) < global_ratio; -} - -/* Must be called with tasklist_lock held */ -static inline int tg_has_rt_tasks(struct task_group *tg) -{ - struct task_struct *g, *p; - do_each_thread(g, p) { - if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) - return 1; - } while_each_thread(g, p); - return 0; -} - -int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) -{ - u64 rt_runtime, rt_period; - int err = 0; - - rt_period = (u64)sysctl_sched_rt_period * NSEC_PER_USEC; - rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; - if (rt_runtime_us == -1) - rt_runtime = RUNTIME_INF; - - mutex_lock(&rt_constraints_mutex); - read_lock(&tasklist_lock); - if (rt_runtime_us == 0 && tg_has_rt_tasks(tg)) { - err = -EBUSY; - goto unlock; - } - if (!__rt_schedulable(tg, rt_period, rt_runtime)) { - err = -EINVAL; - goto unlock; - } - tg->rt_runtime = rt_runtime; - unlock: - read_unlock(&tasklist_lock); - mutex_unlock(&rt_constraints_mutex); - - return err; -} - -long sched_group_rt_runtime(struct task_group *tg) -{ - u64 rt_runtime_us; - - if (tg->rt_runtime == RUNTIME_INF) - return -1; - - rt_runtime_us = tg->rt_runtime; - do_div(rt_runtime_us, NSEC_PER_USEC); - return rt_runtime_us; -} -#endif -#endif /* CONFIG_GROUP_SCHED */ - -#ifdef CONFIG_CGROUP_SCHED - -/* return corresponding task_group object of a cgroup */ -static inline struct task_group *cgroup_tg(struct cgroup *cgrp) -{ - return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), - struct task_group, css); -} - -static struct cgroup_subsys_state * -cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) -{ - struct task_group *tg; - - if (!cgrp->parent) { - /* This is early initialization for the top cgroup */ - init_task_group.css.cgroup = cgrp; - return &init_task_group.css; - } - - /* we support only 1-level deep hierarchical scheduler atm */ - if (cgrp->parent->parent) - return ERR_PTR(-EINVAL); - - tg = sched_create_group(); - if (IS_ERR(tg)) - return ERR_PTR(-ENOMEM); - - /* Bind the cgroup to task_group object we just created */ - tg->css.cgroup = cgrp; - - return &tg->css; -} - -static void -cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) -{ - struct task_group *tg = cgroup_tg(cgrp); - - sched_destroy_group(tg); -} - -static int -cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, - struct task_struct *tsk) -{ -#ifdef CONFIG_RT_GROUP_SCHED - /* Don't accept realtime tasks when there is no way for them to run */ - if (rt_task(tsk) && cgroup_tg(cgrp)->rt_runtime == 0) - return -EINVAL; -#else - /* We don't support RT-tasks being in separate groups */ - if (tsk->sched_class != &fair_sched_class) - return -EINVAL; -#endif - - return 0; -} - -static void -cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, - struct cgroup *old_cont, struct task_struct *tsk) -{ - sched_move_task(tsk); -} - -#ifdef CONFIG_FAIR_GROUP_SCHED -static int cpu_shares_write_uint(struct cgroup *cgrp, struct cftype *cftype, - u64 shareval) -{ - return sched_group_set_shares(cgroup_tg(cgrp), shareval); -} - -static u64 cpu_shares_read_uint(struct cgroup *cgrp, struct cftype *cft) -{ - struct task_group *tg = cgroup_tg(cgrp); - - return (u64) tg->shares; -} -#endif - -#ifdef CONFIG_RT_GROUP_SCHED -static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, - struct file *file, - const char __user *userbuf, - size_t nbytes, loff_t *unused_ppos) -{ - char buffer[64]; - int retval = 0; - s64 val; - char *end; - - if (!nbytes) - return -EINVAL; - if (nbytes >= sizeof(buffer)) - return -E2BIG; - if (copy_from_user(buffer, userbuf, nbytes)) - return -EFAULT; - - buffer[nbytes] = 0; /* nul-terminate */ - - /* strip newline if necessary */ - if (nbytes && (buffer[nbytes-1] == '\n')) - buffer[nbytes-1] = 0; - val = simple_strtoll(buffer, &end, 0); - if (*end) - return -EINVAL; - - /* Pass to subsystem */ - retval = sched_group_set_rt_runtime(cgroup_tg(cgrp), val); - if (!retval) - retval = nbytes; - return retval; -} - -static ssize_t cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft, - struct file *file, - char __user *buf, size_t nbytes, - loff_t *ppos) -{ - char tmp[64]; - long val = sched_group_rt_runtime(cgroup_tg(cgrp)); - int len = sprintf(tmp, "%ld\n", val); - - return simple_read_from_buffer(buf, nbytes, ppos, tmp, len); -} -#endif - -static struct cftype cpu_files[] = { -#ifdef CONFIG_FAIR_GROUP_SCHED - { - .name = "shares", - .read_uint = cpu_shares_read_uint, - .write_uint = cpu_shares_write_uint, - }, -#endif -#ifdef CONFIG_RT_GROUP_SCHED - { - .name = "rt_runtime_us", - .read = cpu_rt_runtime_read, - .write = cpu_rt_runtime_write, - }, -#endif -}; - -static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) -{ - return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); -} - -struct cgroup_subsys cpu_cgroup_subsys = { - .name = "cpu", - .create = cpu_cgroup_create, - .destroy = cpu_cgroup_destroy, - .can_attach = cpu_cgroup_can_attach, - .attach = cpu_cgroup_attach, - .populate = cpu_cgroup_populate, - .subsys_id = cpu_cgroup_subsys_id, - .early_init = 1, -}; - -#endif /* CONFIG_CGROUP_SCHED */ - -#ifdef CONFIG_CGROUP_CPUACCT - -/* - * CPU accounting code for task groups. - * - * Based on the work by Paul Menage (menage@google.com) and Balbir Singh - * (balbir@in.ibm.com). - */ - -/* track cpu usage of a group of tasks */ -struct cpuacct { - struct cgroup_subsys_state css; - /* cpuusage holds pointer to a u64-type object on every cpu */ - u64 *cpuusage; -}; - -struct cgroup_subsys cpuacct_subsys; - -/* return cpu accounting group corresponding to this container */ -static inline struct cpuacct *cgroup_ca(struct cgroup *cont) -{ - return container_of(cgroup_subsys_state(cont, cpuacct_subsys_id), - struct cpuacct, css); -} - -/* return cpu accounting group to which this task belongs */ -static inline struct cpuacct *task_ca(struct task_struct *tsk) -{ - return container_of(task_subsys_state(tsk, cpuacct_subsys_id), - struct cpuacct, css); -} - -/* create a new cpu accounting group */ -static struct cgroup_subsys_state *cpuacct_create( - struct cgroup_subsys *ss, struct cgroup *cont) -{ - struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); - - if (!ca) - return ERR_PTR(-ENOMEM); - - ca->cpuusage = alloc_percpu(u64); - if (!ca->cpuusage) { - kfree(ca); - return ERR_PTR(-ENOMEM); - } - - return &ca->css; -} - -/* destroy an existing cpu accounting group */ -static void -cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cont) -{ - struct cpuacct *ca = cgroup_ca(cont); - - free_percpu(ca->cpuusage); - kfree(ca); -} - -/* return total cpu usage (in nanoseconds) of a group */ -static u64 cpuusage_read(struct cgroup *cont, struct cftype *cft) -{ - struct cpuacct *ca = cgroup_ca(cont); - u64 totalcpuusage = 0; - int i; - - for_each_possible_cpu(i) { - u64 *cpuusage = percpu_ptr(ca->cpuusage, i); - - /* - * Take rq->lock to make 64-bit addition safe on 32-bit - * platforms. - */ - spin_lock_irq(&cpu_rq(i)->lock); - totalcpuusage += *cpuusage; - spin_unlock_irq(&cpu_rq(i)->lock); - } - - return totalcpuusage; -} - -static struct cftype files[] = { - { - .name = "usage", - .read_uint = cpuusage_read, - }, -}; - -static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cont) -{ - return cgroup_add_files(cont, ss, files, ARRAY_SIZE(files)); -} - -/* - * charge this task's execution time to its accounting group. - * - * called with rq->lock held. - */ -static void cpuacct_charge(struct task_struct *tsk, u64 cputime) -{ - struct cpuacct *ca; - - if (!cpuacct_subsys.active) - return; - - ca = task_ca(tsk); - if (ca) { - u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk)); - - *cpuusage += cputime; - } -} - -struct cgroup_subsys cpuacct_subsys = { - .name = "cpuacct", - .create = cpuacct_create, - .destroy = cpuacct_destroy, - .populate = cpuacct_populate, - .subsys_id = cpuacct_subsys_id, -}; -#endif /* CONFIG_CGROUP_CPUACCT */ |