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Diffstat (limited to 'kernel/sched.c')
| -rw-r--r-- | kernel/sched.c | 6254 |
1 files changed, 0 insertions, 6254 deletions
diff --git a/kernel/sched.c b/kernel/sched.c deleted file mode 100644 index 3ee2ae45125..00000000000 --- a/kernel/sched.c +++ /dev/null @@ -1,6254 +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 - */ - -#include <linux/mm.h> -#include <linux/module.h> -#include <linux/nmi.h> -#include <linux/init.h> -#include <asm/uaccess.h> -#include <linux/highmem.h> -#include <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/security.h> -#include <linux/notifier.h> -#include <linux/profile.h> -#include <linux/suspend.h> -#include <linux/vmalloc.h> -#include <linux/blkdev.h> -#include <linux/delay.h> -#include <linux/smp.h> -#include <linux/threads.h> -#include <linux/timer.h> -#include <linux/rcupdate.h> -#include <linux/cpu.h> -#include <linux/cpuset.h> -#include <linux/percpu.h> -#include <linux/kthread.h> -#include <linux/seq_file.h> -#include <linux/syscalls.h> -#include <linux/times.h> -#include <linux/acct.h> -#include <asm/tlb.h> - -#include <asm/unistd.h> - -/* - * 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)) - -/* - * Some helpers for converting nanosecond timing to jiffy resolution - */ -#define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) -#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) - -/* - * These are the 'tuning knobs' of the scheduler: - * - * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger), - * default timeslice is 100 msecs, maximum timeslice is 800 msecs. - * Timeslices get refilled after they expire. - */ -#define MIN_TIMESLICE max(5 * HZ / 1000, 1) -#define DEF_TIMESLICE (100 * HZ / 1000) -#define ON_RUNQUEUE_WEIGHT 30 -#define CHILD_PENALTY 95 -#define PARENT_PENALTY 100 -#define EXIT_WEIGHT 3 -#define PRIO_BONUS_RATIO 25 -#define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100) -#define INTERACTIVE_DELTA 2 -#define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS) -#define STARVATION_LIMIT (MAX_SLEEP_AVG) -#define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG)) - -/* - * If a task is 'interactive' then we reinsert it in the active - * array after it has expired its current timeslice. (it will not - * continue to run immediately, it will still roundrobin with - * other interactive tasks.) - * - * This part scales the interactivity limit depending on niceness. - * - * We scale it linearly, offset by the INTERACTIVE_DELTA delta. - * Here are a few examples of different nice levels: - * - * TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0] - * TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0] - * TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0] - * TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0] - * TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0] - * - * (the X axis represents the possible -5 ... 0 ... +5 dynamic - * priority range a task can explore, a value of '1' means the - * task is rated interactive.) - * - * Ie. nice +19 tasks can never get 'interactive' enough to be - * reinserted into the active array. And only heavily CPU-hog nice -20 - * tasks will be expired. Default nice 0 tasks are somewhere between, - * it takes some effort for them to get interactive, but it's not - * too hard. - */ - -#define CURRENT_BONUS(p) \ - (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \ - MAX_SLEEP_AVG) - -#define GRANULARITY (10 * HZ / 1000 ? : 1) - -#ifdef CONFIG_SMP -#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ - (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \ - num_online_cpus()) -#else -#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ - (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1))) -#endif - -#define SCALE(v1,v1_max,v2_max) \ - (v1) * (v2_max) / (v1_max) - -#define DELTA(p) \ - (SCALE(TASK_NICE(p), 40, MAX_BONUS) + INTERACTIVE_DELTA) - -#define TASK_INTERACTIVE(p) \ - ((p)->prio <= (p)->static_prio - DELTA(p)) - -#define INTERACTIVE_SLEEP(p) \ - (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ - (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) - -#define TASK_PREEMPTS_CURR(p, rq) \ - ((p)->prio < (rq)->curr->prio) - -/* - * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] - * to time slice values: [800ms ... 100ms ... 5ms] - * - * The higher a thread's priority, the bigger timeslices - * it gets during one round of execution. But even the lowest - * priority thread gets MIN_TIMESLICE worth of execution time. - */ - -#define SCALE_PRIO(x, prio) \ - max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO/2), MIN_TIMESLICE) - -static unsigned int task_timeslice(task_t *p) -{ - if (p->static_prio < NICE_TO_PRIO(0)) - return SCALE_PRIO(DEF_TIMESLICE*4, p->static_prio); - else - return SCALE_PRIO(DEF_TIMESLICE, p->static_prio); -} -#define task_hot(p, now, sd) ((long long) ((now) - (p)->last_ran) \ - < (long long) (sd)->cache_hot_time) - -void __put_task_struct_cb(struct rcu_head *rhp) -{ - __put_task_struct(container_of(rhp, struct task_struct, rcu)); -} - -EXPORT_SYMBOL_GPL(__put_task_struct_cb); - -/* - * These are the runqueue data structures: - */ - -#define BITMAP_SIZE ((((MAX_PRIO+1+7)/8)+sizeof(long)-1)/sizeof(long)) - -typedef struct runqueue runqueue_t; - -struct prio_array { - unsigned int nr_active; - unsigned long bitmap[BITMAP_SIZE]; - struct list_head queue[MAX_PRIO]; -}; - -/* - * 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 runqueue { - 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; -#ifdef CONFIG_SMP - unsigned long prio_bias; - unsigned long cpu_load[3]; -#endif - unsigned long long nr_switches; - - /* - * 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; - - unsigned long expired_timestamp; - unsigned long long timestamp_last_tick; - task_t *curr, *idle; - struct mm_struct *prev_mm; - prio_array_t *active, *expired, arrays[2]; - int best_expired_prio; - atomic_t nr_iowait; - -#ifdef CONFIG_SMP - struct sched_domain *sd; - - /* For active balancing */ - int active_balance; - int push_cpu; - - task_t *migration_thread; - struct list_head migration_queue; -#endif - -#ifdef CONFIG_SCHEDSTATS - /* latency stats */ - struct sched_info rq_sched_info; - - /* sys_sched_yield() stats */ - unsigned long yld_exp_empty; - unsigned long yld_act_empty; - unsigned long yld_both_empty; - unsigned long yld_cnt; - - /* schedule() stats */ - unsigned long sched_switch; - unsigned long sched_cnt; - unsigned long sched_goidle; - - /* try_to_wake_up() stats */ - unsigned long ttwu_cnt; - unsigned long ttwu_local; -#endif -}; - -static DEFINE_PER_CPU(struct runqueue, runqueues); - -/* - * 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, domain) \ -for (domain = rcu_dereference(cpu_rq(cpu)->sd); domain; domain = domain->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) - -#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 - -#ifndef __ARCH_WANT_UNLOCKED_CTXSW -static inline int task_running(runqueue_t *rq, task_t *p) -{ - return rq->curr == p; -} - -static inline void prepare_lock_switch(runqueue_t *rq, task_t *next) -{ -} - -static inline void finish_lock_switch(runqueue_t *rq, task_t *prev) -{ -#ifdef CONFIG_DEBUG_SPINLOCK - /* this is a valid case when another task releases the spinlock */ - rq->lock.owner = current; -#endif - spin_unlock_irq(&rq->lock); -} - -#else /* __ARCH_WANT_UNLOCKED_CTXSW */ -static inline int task_running(runqueue_t *rq, task_t *p) -{ -#ifdef CONFIG_SMP - return p->oncpu; -#else - return rq->curr == p; -#endif -} - -static inline void prepare_lock_switch(runqueue_t *rq, task_t *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(runqueue_t *rq, task_t *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 and disable - * interrupts. Note the ordering: we can safely lookup the task_rq without - * explicitly disabling preemption. - */ -static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags) - __acquires(rq->lock) -{ - struct runqueue *rq; - -repeat_lock_task: - local_irq_save(*flags); - rq = task_rq(p); - spin_lock(&rq->lock); - if (unlikely(rq != task_rq(p))) { - spin_unlock_irqrestore(&rq->lock, *flags); - goto repeat_lock_task; - } - return rq; -} - -static inline void task_rq_unlock(runqueue_t *rq, unsigned long *flags) - __releases(rq->lock) -{ - spin_unlock_irqrestore(&rq->lock, *flags); -} - -#ifdef CONFIG_SCHEDSTATS -/* - * bump this up when changing the output format or the meaning of an existing - * format, so that tools can adapt (or abort) - */ -#define SCHEDSTAT_VERSION 12 - -static int show_schedstat(struct seq_file *seq, void *v) -{ - int cpu; - - seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); - seq_printf(seq, "timestamp %lu\n", jiffies); - for_each_online_cpu(cpu) { - runqueue_t *rq = cpu_rq(cpu); -#ifdef CONFIG_SMP - struct sched_domain *sd; - int dcnt = 0; -#endif - - /* runqueue-specific stats */ - seq_printf(seq, - "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu", - cpu, rq->yld_both_empty, - rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt, - rq->sched_switch, rq->sched_cnt, rq->sched_goidle, - rq->ttwu_cnt, rq->ttwu_local, - rq->rq_sched_info.cpu_time, - rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt); - - seq_printf(seq, "\n"); - -#ifdef CONFIG_SMP - /* domain-specific stats */ - preempt_disable(); - for_each_domain(cpu, sd) { - enum idle_type itype; - char mask_str[NR_CPUS]; - - cpumask_scnprintf(mask_str, NR_CPUS, sd->span); - seq_printf(seq, "domain%d %s", dcnt++, mask_str); - for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES; - itype++) { - seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu", - sd->lb_cnt[itype], - sd->lb_balanced[itype], - sd->lb_failed[itype], - sd->lb_imbalance[itype], - sd->lb_gained[itype], - sd->lb_hot_gained[itype], - sd->lb_nobusyq[itype], - sd->lb_nobusyg[itype]); - } - seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n", - sd->alb_cnt, sd->alb_failed, sd->alb_pushed, - sd->sbe_cnt, sd->sbe_balanced, sd->sbe_pushed, - sd->sbf_cnt, sd->sbf_balanced, sd->sbf_pushed, - sd->ttwu_wake_remote, sd->ttwu_move_affine, sd->ttwu_move_balance); - } - preempt_enable(); -#endif - } - return 0; -} - -static int schedstat_open(struct inode *inode, struct file *file) -{ - unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32); - char *buf = kmalloc(size, GFP_KERNEL); - struct seq_file *m; - int res; - - if (!buf) - return -ENOMEM; - res = single_open(file, show_schedstat, NULL); - if (!res) { - m = file->private_data; - m->buf = buf; - m->size = size; - } else - kfree(buf); - return res; -} - -struct file_operations proc_schedstat_operations = { - .open = schedstat_open, - .read = seq_read, - .llseek = seq_lseek, - .release = single_release, -}; - -# define schedstat_inc(rq, field) do { (rq)->field++; } while (0) -# define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0) -#else /* !CONFIG_SCHEDSTATS */ -# define schedstat_inc(rq, field) do { } while (0) -# define schedstat_add(rq, field, amt) do { } while (0) -#endif - -/* - * rq_lock - lock a given runqueue and disable interrupts. - */ -static inline runqueue_t *this_rq_lock(void) - __acquires(rq->lock) -{ - runqueue_t *rq; - - local_irq_disable(); - rq = this_rq(); - spin_lock(&rq->lock); - - return rq; -} - -#ifdef CONFIG_SCHEDSTATS -/* - * Called when a process is dequeued from the active array and given - * the cpu. We should note that with the exception of interactive - * tasks, the expired queue will become the active queue after the active - * queue is empty, without explicitly dequeuing and requeuing tasks in the - * expired queue. (Interactive tasks may be requeued directly to the - * active queue, thus delaying tasks in the expired queue from running; - * see scheduler_tick()). - * - * This function is only called from sched_info_arrive(), rather than - * dequeue_task(). Even though a task may be queued and dequeued multiple - * times as it is shuffled about, we're really interested in knowing how - * long it was from the *first* time it was queued to the time that it - * finally hit a cpu. - */ -static inline void sched_info_dequeued(task_t *t) -{ - t->sched_info.last_queued = 0; -} - -/* - * Called when a task finally hits the cpu. We can now calculate how - * long it was waiting to run. We also note when it began so that we - * can keep stats on how long its timeslice is. - */ -static void sched_info_arrive(task_t *t) -{ - unsigned long now = jiffies, diff = 0; - struct runqueue *rq = task_rq(t); - - if (t->sched_info.last_queued) - diff = now - t->sched_info.last_queued; - sched_info_dequeued(t); - t->sched_info.run_delay += diff; - t->sched_info.last_arrival = now; - t->sched_info.pcnt++; - - if (!rq) - return; - - rq->rq_sched_info.run_delay += diff; - rq->rq_sched_info.pcnt++; -} - -/* - * Called when a process is queued into either the active or expired - * array. The time is noted and later used to determine how long we - * had to wait for us to reach the cpu. Since the expired queue will - * become the active queue after active queue is empty, without dequeuing - * and requeuing any tasks, we are interested in queuing to either. It - * is unusual but not impossible for tasks to be dequeued and immediately - * requeued in the same or another array: this can happen in sched_yield(), - * set_user_nice(), and even load_balance() as it moves tasks from runqueue - * to runqueue. - * - * This function is only called from enqueue_task(), but also only updates - * the timestamp if it is already not set. It's assumed that - * sched_info_dequeued() will clear that stamp when appropriate. - */ -static inline void sched_info_queued(task_t *t) -{ - if (!t->sched_info.last_queued) - t->sched_info.last_queued = jiffies; -} - -/* - * Called when a process ceases being the active-running process, either - * voluntarily or involuntarily. Now we can calculate how long we ran. - */ -static inline void sched_info_depart(task_t *t) -{ - struct runqueue *rq = task_rq(t); - unsigned long diff = jiffies - t->sched_info.last_arrival; - - t->sched_info.cpu_time += diff; - - if (rq) - rq->rq_sched_info.cpu_time += diff; -} - -/* - * Called when tasks are switched involuntarily due, typically, to expiring - * their time slice. (This may also be called when switching to or from - * the idle task.) We are only called when prev != next. - */ -static inline void sched_info_switch(task_t *prev, task_t *next) -{ - struct runqueue *rq = task_rq(prev); - - /* - * prev now departs the cpu. It's not interesting to record - * stats about how efficient we were at scheduling the idle - * process, however. - */ - if (prev != rq->idle) - sched_info_depart(prev); - - if (next != rq->idle) - sched_info_arrive(next); -} -#else -#define sched_info_queued(t) do { } while (0) -#define sched_info_switch(t, next) do { } while (0) -#endif /* CONFIG_SCHEDSTATS */ - -/* - * Adding/removing a task to/from a priority array: - */ -static void dequeue_task(struct task_struct *p, prio_array_t *array) -{ - array->nr_active--; - list_del(&p->run_list); - if (list_empty(array->queue + p->prio)) - __clear_bit(p->prio, array->bitmap); -} - -static void enqueue_task(struct task_struct *p, prio_array_t *array) -{ - sched_info_queued(p); - list_add_tail(&p->run_list, array->queue + p->prio); - __set_bit(p->prio, array->bitmap); - array->nr_active++; - p->array = array; -} - -/* - * Put task to the end of the run list without the overhead of dequeue - * followed by enqueue. - */ -static void requeue_task(struct task_struct *p, prio_array_t *array) -{ - list_move_tail(&p->run_list, array->queue + p->prio); -} - -static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array) -{ - list_add(&p->run_list, array->queue + p->prio); - __set_bit(p->prio, array->bitmap); - array->nr_active++; - p->array = array; -} - -/* - * effective_prio - return the priority that is based on the static - * priority but is modified by bonuses/penalties. - * - * We scale the actual sleep average [0 .... MAX_SLEEP_AVG] - * into the -5 ... 0 ... +5 bonus/penalty range. - * - * We use 25% of the full 0...39 priority range so that: - * - * 1) nice +19 interactive tasks do not preempt nice 0 CPU hogs. - * 2) nice -20 CPU hogs do not get preempted by nice 0 tasks. - * - * Both properties are important to certain workloads. - */ -static int effective_prio(task_t *p) -{ - int bonus, prio; - - if (rt_task(p)) - return p->prio; - - bonus = CURRENT_BONUS(p) - MAX_BONUS / 2; - - prio = p->static_prio - bonus; - if (prio < MAX_RT_PRIO) - prio = MAX_RT_PRIO; - if (prio > MAX_PRIO-1) - prio = MAX_PRIO-1; - return prio; -} - -#ifdef CONFIG_SMP -static inline void inc_prio_bias(runqueue_t *rq, int prio) -{ - rq->prio_bias += MAX_PRIO - prio; -} - -static inline void dec_prio_bias(runqueue_t *rq, int prio) -{ - rq->prio_bias -= MAX_PRIO - prio; -} - -static inline void inc_nr_running(task_t *p, runqueue_t *rq) -{ - rq->nr_running++; - if (rt_task(p)) { - if (p != rq->migration_thread) - /* - * The migration thread does the actual balancing. Do - * not bias by its priority as the ultra high priority - * will skew balancing adversely. - */ - inc_prio_bias(rq, p->prio); - } else - inc_prio_bias(rq, p->static_prio); -} - -static inline void dec_nr_running(task_t *p, runqueue_t *rq) -{ - rq->nr_running--; - if (rt_task(p)) { - if (p != rq->migration_thread) - dec_prio_bias(rq, p->prio); - } else - dec_prio_bias(rq, p->static_prio); -} -#else -static inline void inc_prio_bias(runqueue_t *rq, int prio) -{ -} - -static inline void dec_prio_bias(runqueue_t *rq, int prio) -{ -} - -static inline void inc_nr_running(task_t *p, runqueue_t *rq) -{ - rq->nr_running++; -} - -static inline void dec_nr_running(task_t *p, runqueue_t *rq) -{ - rq->nr_running--; -} -#endif - -/* - * __activate_task - move a task to the runqueue. - */ -static inline void __activate_task(task_t *p, runqueue_t *rq) -{ - enqueue_task(p, rq->active); - inc_nr_running(p, rq); -} - -/* - * __activate_idle_task - move idle task to the _front_ of runqueue. - */ -static inline void __activate_idle_task(task_t *p, runqueue_t *rq) -{ - enqueue_task_head(p, rq->active); - inc_nr_running(p, rq); -} - -static int recalc_task_prio(task_t *p, unsigned long long now) -{ - /* Caller must always ensure 'now >= p->timestamp' */ - unsigned long long __sleep_time = now - p->timestamp; - unsigned long sleep_time; - - if (unlikely(p->policy == SCHED_BATCH)) - sleep_time = 0; - else { - if (__sleep_time > NS_MAX_SLEEP_AVG) - sleep_time = NS_MAX_SLEEP_AVG; - else - sleep_time = (unsigned long)__sleep_time; - } - - if (likely(sleep_time > 0)) { - /* - * User tasks that sleep a long time are categorised as - * idle and will get just interactive status to stay active & - * prevent them suddenly becoming cpu hogs and starving - * other processes. - */ - if (p->mm && p->activated != -1 && - sleep_time > INTERACTIVE_SLEEP(p)) { - p->sleep_avg = JIFFIES_TO_NS(MAX_SLEEP_AVG - - DEF_TIMESLICE); - } else { - /* - * The lower the sleep avg a task has the more - * rapidly it will rise with sleep time. - */ - sleep_time *= (MAX_BONUS - CURRENT_BONUS(p)) ? : 1; - - /* - * Tasks waking from uninterruptible sleep are - * limited in their sleep_avg rise as they - * are likely to be waiting on I/O - */ - if (p->activated == -1 && p->mm) { - if (p->sleep_avg >= INTERACTIVE_SLEEP(p)) - sleep_time = 0; - else if (p->sleep_avg + sleep_time >= - INTERACTIVE_SLEEP(p)) { - p->sleep_avg = INTERACTIVE_SLEEP(p); - sleep_time = 0; - } - } - - /* - * This code gives a bonus to interactive tasks. - * - * The boost works by updating the 'average sleep time' - * value here, based on ->timestamp. The more time a - * task spends sleeping, the higher the average gets - - * and the higher the priority boost gets as well. - */ - p->sleep_avg += sleep_time; - - if (p->sleep_avg > NS_MAX_SLEEP_AVG) - p->sleep_avg = NS_MAX_SLEEP_AVG; - } - } - - return effective_prio(p); -} - -/* - * activate_task - move a task to the runqueue and do priority recalculation - * - * Update all the scheduling statistics stuff. (sleep average - * calculation, priority modifiers, etc.) - */ -static void activate_task(task_t *p, runqueue_t *rq, int local) -{ - unsigned long long now; - - now = sched_clock(); -#ifdef CONFIG_SMP - if (!local) { - /* Compensate for drifting sched_clock */ - runqueue_t *this_rq = this_rq(); - now = (now - this_rq->timestamp_last_tick) - + rq->timestamp_last_tick; - } -#endif - - if (!rt_task(p)) - p->prio = recalc_task_prio(p, now); - - /* - * This checks to make sure it's not an uninterruptible task - * that is now waking up. - */ - if (!p->activated) { - /* - * Tasks which were woken up by interrupts (ie. hw events) - * are most likely of interactive nature. So we give them - * the credit of extending their sleep time to the period - * of time they spend on the runqueue, waiting for execution - * on a CPU, first time around: - */ - if (in_interrupt()) - p->activated = 2; - else { - /* - * Normal first-time wakeups get a credit too for - * on-runqueue time, but it will be weighted down: - */ - p->activated = 1; - } - } - p->timestamp = now; - - __activate_task(p, rq); -} - -/* - * deactivate_task - remove a task from the runqueue. - */ -static void deactivate_task(struct task_struct *p, runqueue_t *rq) -{ - dec_nr_running(p, rq); - dequeue_task(p, p->array); - p->array = NULL; -} - -/* - * 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 -static void resched_task(task_t *p) -{ - int cpu; - - assert_spin_locked(&task_rq(p)->lock); - - if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) - return; - - set_tsk_thread_flag(p, TIF_NEED_RESCHED); - - cpu = task_cpu(p); - if (cpu == smp_processor_id()) - return; - - /* NEED_RESCHED must be visible before we test POLLING_NRFLAG */ - smp_mb(); - if (!test_tsk_thread_flag(p, TIF_POLLING_NRFLAG)) - smp_send_reschedule(cpu); -} -#else -static inline void resched_task(task_t *p) -{ - assert_spin_locked(&task_rq(p)->lock); - set_tsk_need_resched(p); -} -#endif - -/** - * task_curr - is this task currently executing on a CPU? - * @p: the task in question. - */ -inline int task_curr(const task_t *p) -{ - return cpu_curr(task_cpu(p)) == p; -} - -#ifdef CONFIG_SMP -typedef struct { - struct list_head list; - - task_t *task; - int dest_cpu; - - struct completion done; -} migration_req_t; - -/* - * The task's runqueue lock must be held. - * Returns true if you have to wait for migration thread. - */ -static int migrate_task(task_t *p, int dest_cpu, migration_req_t *req) -{ - runqueue_t *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->array && !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(task_t *p) -{ - unsigned long flags; - runqueue_t *rq; - int preempted; - -repeat: - rq = task_rq_lock(p, &flags); - /* Must be off runqueue entirely, not preempted. */ - if (unlikely(p->array || task_running(rq, p))) { - /* If it's preempted, we yield. It could be a while. */ - preempted = !task_running(rq, p); - task_rq_unlock(rq, &flags); - cpu_relax(); - if (preempted) - yield(); - goto repeat; - } - task_rq_unlock(rq, &flags); -} - -/*** - * 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(task_t *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. - * - * We want to under-estimate the load of migration sources, to - * balance conservatively. - */ -static unsigned long __source_load(int cpu, int type, enum idle_type idle) -{ - runqueue_t *rq = cpu_rq(cpu); - unsigned long running = rq->nr_running; - unsigned long source_load, cpu_load = rq->cpu_load[type-1], - load_now = running * SCHED_LOAD_SCALE; - - if (type == 0) - source_load = load_now; - else - source_load = min(cpu_load, load_now); - - if (running > 1 || (idle == NOT_IDLE && running)) - /* - * If we are busy rebalancing the load is biased by - * priority to create 'nice' support across cpus. When - * idle rebalancing we should only bias the source_load if - * there is more than one task running on that queue to - * prevent idle rebalance from trying to pull tasks from a - * queue with only one running task. - */ - source_load = source_load * rq->prio_bias / running; - - return source_load; -} - -static inline unsigned long source_load(int cpu, int type) -{ - return __source_load(cpu, type, NOT_IDLE); -} - -/* - * Return a high guess at the load of a migration-target cpu - */ -static inline unsigned long __target_load(int cpu, int type, enum idle_type idle) -{ - runqueue_t *rq = cpu_rq(cpu); - unsigned long running = rq->nr_running; - unsigned long target_load, cpu_load = rq->cpu_load[type-1], - load_now = running * SCHED_LOAD_SCALE; - - if (type == 0) - target_load = load_now; - else - target_load = max(cpu_load, load_now); - - if (running > 1 || (idle == NOT_IDLE && running)) - target_load = target_load * rq->prio_bias / running; - - return target_load; -} - -static inline unsigned long target_load(int cpu, int type) -{ - return __target_load(cpu, type, NOT_IDLE); -} - -/* - * 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)) - goto nextgroup; - - 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 = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; - - if (local_group) { - this_load = avg_load; - this = group; - } else if (avg_load < min_load) { - min_load = avg_load; - idlest = group; - } -nextgroup: - group = group->next; - } while (group != sd->groups); - - if (!idlest || 100*this_load < imbalance*min_load) - return NULL; - return idlest; -} - -/* - * find_idlest_queue - find the idlest runqueue 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 = source_load(i, 0); - - 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 (tmp->flags & flag) - sd = tmp; - - while (sd) { - cpumask_t span; - struct sched_group *group; - int new_cpu; - int weight; - - span = sd->span; - group = find_idlest_group(sd, t, cpu); - if (!group) - goto nextlevel; - - new_cpu = find_idlest_cpu(group, t, cpu); - if (new_cpu == -1 || new_cpu == cpu) - goto nextlevel; - - /* Now try balancing at a lower domain level */ - cpu = new_cpu; -nextlevel: - 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 */ - -/* - * wake_idle() will wake a task on an idle cpu if task->cpu is - * not idle and an idle cpu is available. The span of cpus to - * search starts with cpus closest then further out as needed, - * so we always favor a closer, idle cpu. - * - * Returns the CPU we should wake onto. - */ -#if defined(ARCH_HAS_SCHED_WAKE_IDLE) -static int wake_idle(int cpu, task_t *p) -{ - cpumask_t tmp; - struct sched_domain *sd; - int i; - - if (idle_cpu(cpu)) - return cpu; - - for_each_domain(cpu, sd) { - if (sd->flags & SD_WAKE_IDLE) { - cpus_and(tmp, sd->span, p->cpus_allowed); - for_each_cpu_mask(i, tmp) { - if (idle_cpu(i)) - return i; - } - } - else - break; - } - return cpu; -} -#else -static inline int wake_idle(int cpu, task_t *p) -{ - return cpu; -} -#endif - -/*** - * 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(task_t *p, unsigned int state, int sync) -{ - int cpu, this_cpu, success = 0; - unsigned long flags; - long old_state; - runqueue_t *rq; -#ifdef CONFIG_SMP - unsigned long load, this_load; - struct sched_domain *sd, *this_sd = NULL; - int new_cpu; -#endif - - rq = task_rq_lock(p, &flags); - old_state = p->state; - if (!(old_state & state)) - goto out; - - if (p->array) - goto out_running; - - cpu = task_cpu(p); - this_cpu = smp_processor_id(); - -#ifdef CONFIG_SMP - if (unlikely(task_running(rq, p))) - goto out_activate; - - new_cpu = cpu; - - schedstat_inc(rq, ttwu_cnt); - if (cpu == this_cpu) { - schedstat_inc(rq, ttwu_local); - goto out_set_cpu; - } - - for_each_domain(this_cpu, sd) { - if (cpu_isset(cpu, sd->span)) { - schedstat_inc(sd, ttwu_wake_remote); - this_sd = sd; - break; - } - } - - if (p->last_waker_cpu != this_cpu) - goto out_set_cpu; - - if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) - goto out_set_cpu; - - /* - * Check for affine wakeup and passive balancing possibilities. - */ - if (this_sd) { - int idx = this_sd->wake_idx; - unsigned int imbalance; - - imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; - - load = source_load(cpu, idx); - this_load = target_load(this_cpu, idx); - - new_cpu = this_cpu; /* Wake to this CPU if we can */ - - if (this_sd->flags & SD_WAKE_AFFINE) { - unsigned long tl = this_load; - /* - * If sync wakeup then subtract the (maximum possible) - * effect of the currently running task from the load - * of the current CPU: - */ - if (sync) - tl -= SCHED_LOAD_SCALE; - - if ((tl <= load && - tl + target_load(cpu, idx) <= SCHED_LOAD_SCALE) || - 100*(tl + SCHED_LOAD_SCALE) <= imbalance*load) { - /* - * This domain has SD_WAKE_AFFINE and - * p is cache cold in this domain, and - * there is no bad imbalance. - */ - schedstat_inc(this_sd, ttwu_move_affine); - goto out_set_cpu; - } - } - - /* - * Start passive balancing when half the imbalance_pct - * limit is reached. - */ - if (this_sd->flags & SD_WAKE_BALANCE) { - if (imbalance*this_load <= 100*load) { - schedstat_inc(this_sd, ttwu_move_balance); - goto out_set_cpu; - } - } - } - - new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ -out_set_cpu: - new_cpu = wake_idle(new_cpu, p); - if (new_cpu != cpu) { - set_task_cpu(p, new_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->array) - goto out_running; - - this_cpu = smp_processor_id(); - cpu = task_cpu(p); - } - - p->last_waker_cpu = this_cpu; - -out_activate: -#endif /* CONFIG_SMP */ - if (old_state == TASK_UNINTERRUPTIBLE) { - rq->nr_uninterruptible--; - /* - * Tasks on involuntary sleep don't earn - * sleep_avg beyond just interactive state. - */ - p->activated = -1; - } - - /* - * Tasks that have marked their sleep as noninteractive get - * woken up without updating their sleep average. (i.e. their - * sleep is handled in a priority-neutral manner, no priority - * boost and no penalty.) - */ - if (old_state & TASK_NONINTERACTIVE) - __activate_task(p, rq); - else - activate_task(p, rq, cpu == this_cpu); - /* - * Sync wakeups (i.e. those types of wakeups where the waker - * has indicated that it will leave the CPU in short order) - * don't trigger a preemption, if the woken up task will run on - * this cpu. (in this case the 'I will reschedule' promise of - * the waker guarantees that the freshly woken up task is going - * to be considered on this CPU.) - */ - if (!sync || cpu != this_cpu) { - if (TASK_PREEMPTS_CURR(p, rq)) - resched_task(rq->curr); - } - success = 1; - -out_running: - p->state = TASK_RUNNING; -out: - task_rq_unlock(rq, &flags); - - return success; -} - -int fastcall wake_up_process(task_t *p) -{ - return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | - TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); -} - -EXPORT_SYMBOL(wake_up_process); - -int fastcall wake_up_state(task_t *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. - */ -void fastcall sched_fork(task_t *p, int clone_flags) -{ - int cpu = get_cpu(); - -#ifdef CONFIG_SMP - cpu = sched_balance_self(cpu, SD_BALANCE_FORK); -#endif - set_task_cpu(p, cpu); - - /* - * 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; - INIT_LIST_HEAD(&p->run_list); - p->array = NULL; -#ifdef CONFIG_SCHEDSTATS - memset(&p->sched_info, 0, sizeof(p->sched_info)); -#endif -#if defined(CONFIG_SMP) - p->last_waker_cpu = cpu; -#if defined(__ARCH_WANT_UNLOCKED_CTXSW) - p->oncpu = 0; -#endif -#endif -#ifdef CONFIG_PREEMPT - /* Want to start with kernel preemption disabled. */ - task_thread_info(p)->preempt_count = 1; -#endif - /* - * Share the timeslice between parent and child, thus the - * total amount of pending timeslices in the system doesn't change, - * resulting in more scheduling fairness. - */ - local_irq_disable(); - p->time_slice = (current->time_slice + 1) >> 1; - /* - * The remainder of the first timeslice might be recovered by - * the parent if the child exits early enough. - */ - p->first_time_slice = 1; - current->time_slice >>= 1; - p->timestamp = sched_clock(); - if (unlikely(!current->time_slice)) { - /* - * This case is rare, it happens when the parent has only - * a single jiffy left from its timeslice. Taking the - * runqueue lock is not a problem. - */ - current->time_slice = 1; - scheduler_tick(); - } - local_irq_enable(); - 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 fastcall wake_up_new_task(task_t *p, unsigned long clone_flags) -{ - unsigned long flags; - int this_cpu, cpu; - runqueue_t *rq, *this_rq; - - rq = task_rq_lock(p, &flags); - BUG_ON(p->state != TASK_RUNNING); - this_cpu = smp_processor_id(); - cpu = task_cpu(p); - - /* - * We decrease the sleep average of forking parents - * and children as well, to keep max-interactive tasks - * from forking tasks that are max-interactive. The parent - * (current) is done further down, under its lock. - */ - p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) * - CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - - p->prio = effective_prio(p); - - if (likely(cpu == this_cpu)) { - if (!(clone_flags & CLONE_VM)) { - /* - * The VM isn't cloned, so we're in a good position to - * do child-runs-first in anticipation of an exec. This - * usually avoids a lot of COW overhead. - */ - if (unlikely(!current->array)) - __activate_task(p, rq); - else { - p->prio = current->prio; - list_add_tail(&p->run_list, ¤t->run_list); - p->array = current->array; - p->array->nr_active++; - inc_nr_running(p, rq); - } - set_need_resched(); - } else - /* Run child last */ - __activate_task(p, rq); - /* - * We skip the following code due to cpu == this_cpu - * - * task_rq_unlock(rq, &flags); - * this_rq = task_rq_lock(current, &flags); - */ - this_rq = rq; - } else { - this_rq = cpu_rq(this_cpu); - - /* - * Not the local CPU - must adjust timestamp. This should - * get optimised away in the !CONFIG_SMP case. - */ - p->timestamp = (p->timestamp - this_rq->timestamp_last_tick) - + rq->timestamp_last_tick; - __activate_task(p, rq); - if (TASK_PREEMPTS_CURR(p, rq)) - resched_task(rq->curr); - - /* - * Parent and child are on different CPUs, now get the - * parent runqueue to update the parent's ->sleep_avg: - */ - task_rq_unlock(rq, &flags); - this_rq = task_rq_lock(current, &flags); - } - current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) * - PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); - task_rq_unlock(this_rq, &flags); -} - -/* - * Potentially available exiting-child timeslices are - * retrieved here - this way the parent does not get - * penalized for creating too many threads. - * - * (this cannot be used to 'generate' timeslices - * artificially, because any timeslice recovered here - * was given away by the parent in the first place.) - */ -void fastcall sched_exit(task_t *p) -{ - unsigned long flags; - runqueue_t *rq; - - /* - * If the child was a (relative-) CPU hog then decrease - * the sleep_avg of the parent as well. - */ - rq = task_rq_lock(p->parent, &flags); - if (p->first_time_slice && task_cpu(p) == task_cpu(p->parent)) { - p->parent->time_slice += p->time_slice; - if (unlikely(p->parent->time_slice > task_timeslice(p))) - p->parent->time_slice = task_timeslice(p); - } - if (p->sleep_avg < p->parent->sleep_avg) - p->parent->sleep_avg = p->parent->sleep_avg / - (EXIT_WEIGHT + 1) * EXIT_WEIGHT + p->sleep_avg / - (EXIT_WEIGHT + 1); - task_rq_unlock(rq, &flags); -} - -/** - * prepare_task_switch - prepare to switch tasks - * @rq: the runqueue preparing to switch - * @next: the task we are going to switch to. - * - * This is called with the rq lock held and interrupts off. It must - * be paired with a subsequent finish_task_switch after the context - * switch. - * - * prepare_task_switch sets up locking and calls architecture specific - * hooks. - */ -static inline void prepare_task_switch(runqueue_t *rq, task_t *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 inline void finish_task_switch(runqueue_t *rq, task_t *prev) - __releases(rq->lock) -{ - struct mm_struct *mm = rq->prev_mm; - unsigned long prev_task_flags; - - rq->prev_mm = NULL; - - /* - * A task struct has one reference for the use as "current". - * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and - * calls schedule one last time. The schedule call will never return, - * and the scheduled task must drop that reference. - * The test for EXIT_ZOMBIE 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_task_flags = prev->flags; - finish_arch_switch(prev); - finish_lock_switch(rq, prev); - if (mm) - mmdrop(mm); - if (unlikely(prev_task_flags & PF_DEAD)) - 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(task_t *prev) - __releases(rq->lock) -{ - runqueue_t *rq = this_rq(); - finish_task_switch(rq, prev); -#ifdef __ARCH_WANT_UNLOCKED_CTXSW - /* In this case, finish_task_switch does not reenable preemption */ - preempt_enable(); -#endif - if (current->set_child_tid) - put_user(current->pid, current->set_child_tid); -} - -/* - * context_switch - switch to the new MM and the new - * thread's register state. - */ -static inline -task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next) -{ - struct mm_struct *mm = next->mm; - struct mm_struct *oldmm = prev->active_mm; - - 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; - WARN_ON(rq->prev_mm); - rq->prev_mm = oldmm; - } - - /* Here we just switch the register state and the stack. */ - switch_to(prev, next, prev); - - return 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_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) -{ - unsigned long long i, sum = 0; - - for_each_cpu(i) - sum += cpu_rq(i)->nr_switches; - - return sum; -} - -unsigned long nr_iowait(void) -{ - unsigned long i, sum = 0; - - for_each_cpu(i) - sum += atomic_read(&cpu_rq(i)->nr_iowait); - - return sum; -} - -#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(runqueue_t *rq1, runqueue_t *rq2) - __acquires(rq1->lock) - __acquires(rq2->lock) -{ - 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); - } - } -} - -/* - * 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(runqueue_t *rq1, runqueue_t *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 void double_lock_balance(runqueue_t *this_rq, runqueue_t *busiest) - __releases(this_rq->lock) - __acquires(busiest->lock) - __acquires(this_rq->lock) -{ - if (unlikely(!spin_trylock(&busiest->lock))) { - if (busiest < this_rq) { - spin_unlock(&this_rq->lock); - spin_lock(&busiest->lock); - spin_lock(&this_rq->lock); - } else - spin_lock(&busiest->lock); - } -} - -/* - * 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(task_t *p, int dest_cpu) -{ - migration_req_t req; - runqueue_t *rq; - unsigned long flags; - - 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(runqueue_t *src_rq, prio_array_t *src_array, task_t *p, - runqueue_t *this_rq, prio_array_t *this_array, int this_cpu) -{ - dequeue_task(p, src_array); - dec_nr_running(p, src_rq); - set_task_cpu(p, this_cpu); - inc_nr_running(p, this_rq); - enqueue_task(p, this_array); - p->timestamp = (p->timestamp - src_rq->timestamp_last_tick) - + this_rq->timestamp_last_tick; - /* - * Note that idle threads have a prio of MAX_PRIO, for this test - * to be always true for them. - */ - if (TASK_PREEMPTS_CURR(p, this_rq)) - resched_task(this_rq->curr); -} - -/* - * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? - */ -static -int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu, - struct sched_domain *sd, enum 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)) - return 0; - *all_pinned = 0; - - if (task_running(rq, p)) - return 0; - - /* - * Aggressive migration if: - * 1) task is cache cold, or - * 2) too many balance attempts have failed. - */ - - if (sd->nr_balance_failed > sd->cache_nice_tries) - return 1; - - if (task_hot(p, rq->timestamp_last_tick, sd)) - return 0; - return 1; -} - -/* - * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq, - * as part of a balancing operation within "domain". Returns the number of - * tasks moved. - * - * Called with both runqueues locked. - */ -static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest, - unsigned long max_nr_move, struct sched_domain *sd, - enum idle_type idle, int *all_pinned) -{ - prio_array_t *array, *dst_array; - struct list_head *head, *curr; - int idx, pulled = 0, pinned = 0; - task_t *tmp; - - if (max_nr_move == 0) - goto out; - - pinned = 1; - - /* - * We first consider expired tasks. Those will likely not be - * executed in the near future, and they are most likely to - * be cache-cold, thus switching CPUs has the least effect - * on them. - */ - if (busiest->expired->nr_active) { - array = busiest->expired; - dst_array = this_rq->expired; - } else { - array = busiest->active; - dst_array = this_rq->active; - } - -new_array: - /* Start searching at priority 0: */ - idx = 0; -skip_bitmap: - if (!idx) - idx = sched_find_first_bit(array->bitmap); - else - idx = find_next_bit(array->bitmap, MAX_PRIO, idx); - if (idx >= MAX_PRIO) { - if (array == busiest->expired && busiest->active->nr_active) { - array = busiest->active; - dst_array = this_rq->active; - goto new_array; - } - goto out; - } - - head = array->queue + idx; - curr = head->prev; -skip_queue: - tmp = list_entry(curr, task_t, run_list); - - curr = curr->prev; - - if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) { - if (curr != head) - goto skip_queue; - idx++; - goto skip_bitmap; - } - -#ifdef CONFIG_SCHEDSTATS - if (task_hot(tmp, busiest->timestamp_last_tick, sd)) - schedstat_inc(sd, lb_hot_gained[idle]); -#endif - - pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu); - pulled++; - - /* We only want to steal up to the prescribed number of tasks. */ - if (pulled < max_nr_move) { - if (curr != head) - goto skip_queue; - idx++; - goto skip_bitmap; - } -out: - /* - * Right now, this is the only place 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 pulled; -} - -/* - * find_busiest_group finds and returns the busiest CPU group within the - * domain. It calculates and returns the number of tasks 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 idle_type idle, int *sd_idle) -{ - 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; - int load_idx; - - max_load = this_load = total_load = total_pwr = 0; - if (idle == NOT_IDLE) - load_idx = sd->busy_idx; - else if (idle == NEWLY_IDLE) - load_idx = sd->newidle_idx; - else - load_idx = sd->idle_idx; - - do { - unsigned long load; - int local_group; - int i; - - 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) { - if (*sd_idle && !idle_cpu(i)) - *sd_idle = 0; - - /* Bias balancing toward cpus of our domain */ - if (local_group) - load = __target_load(i, load_idx, idle); - else - load = __source_load(i, load_idx, idle); - - avg_load += load; - } - - total_load += avg_load; - total_pwr += group->cpu_power; - - /* Adjust by relative CPU power of the group */ - avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; - - if (local_group) { - this_load = avg_load; - this = group; - } else if (avg_load > max_load) { - max_load = avg_load; - busiest = group; - } - group = group->next; - } while (group != sd->groups); - - if (!busiest || this_load >= max_load || max_load <= SCHED_LOAD_SCALE) - 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; - - /* - * 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. - */ - - /* Don't want to pull so many tasks that a group would go idle */ - max_pull = min(max_load - avg_load, max_load - SCHED_LOAD_SCALE); - - /* 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 < SCHED_LOAD_SCALE) { - unsigned long pwr_now = 0, pwr_move = 0; - unsigned long tmp; - - if (max_load - this_load >= SCHED_LOAD_SCALE*2) { - *imbalance = 1; - 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(SCHED_LOAD_SCALE, max_load); - pwr_now += this->cpu_power*min(SCHED_LOAD_SCALE, this_load); - pwr_now /= SCHED_LOAD_SCALE; - - /* Amount of load we'd subtract */ - tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/busiest->cpu_power; - if (max_load > tmp) - pwr_move += busiest->cpu_power*min(SCHED_LOAD_SCALE, - max_load - tmp); - - /* Amount of load we'd add */ - if (max_load*busiest->cpu_power < - SCHED_LOAD_SCALE*SCHED_LOAD_SCALE) - tmp = max_load*busiest->cpu_power/this->cpu_power; - else - tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power; - pwr_move += this->cpu_power*min(SCHED_LOAD_SCALE, this_load + tmp); - pwr_move /= SCHED_LOAD_SCALE; - - /* Move if we gain throughput */ - if (pwr_move <= pwr_now) - goto out_balanced; - - *imbalance = 1; - return busiest; - } - - /* Get rid of the scaling factor, rounding down as we divide */ - *imbalance = *imbalance / SCHED_LOAD_SCALE; - return busiest; - -out_balanced: - - *imbalance = 0; - return NULL; -} - -/* - * find_busiest_queue - find the busiest runqueue among the cpus in group. - */ -static runqueue_t *find_busiest_queue(struct sched_group *group, - enum idle_type idle) -{ - unsigned long load, max_load = 0; - runqueue_t *busiest = NULL; - int i; - - for_each_cpu_mask(i, group->cpumask) { - load = __source_load(i, 0, idle); - - if (load > max_load) { - max_load = load; - busiest = cpu_rq(i); - } - } - - 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. - * - * Called with this_rq unlocked. - */ -static int load_balance(int this_cpu, runqueue_t *this_rq, - struct sched_domain *sd, enum idle_type idle) -{ - struct sched_group *group; - runqueue_t *busiest; - unsigned long imbalance; - int nr_moved, all_pinned = 0; - int active_balance = 0; - int sd_idle = 0; - - if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER) - sd_idle = 1; - - schedstat_inc(sd, lb_cnt[idle]); - - group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle); - if (!group) { - schedstat_inc(sd, lb_nobusyg[idle]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, idle); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[idle]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[idle], imbalance); - - nr_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. nr_moved simply stays zero, so it is - * correctly treated as an imbalance. - */ - double_rq_lock(this_rq, busiest); - nr_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, idle, &all_pinned); - double_rq_unlock(this_rq, busiest); - - /* All tasks on this runqueue were pinned by CPU affinity */ - if (unlikely(all_pinned)) - goto out_balanced; - } - - if (!nr_moved) { - schedstat_inc(sd, lb_failed[idle]); - sd->nr_balance_failed++; - - if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { - - spin_lock(&busiest->lock); - - /* 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(&busiest->lock); - 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(&busiest->lock); - 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 (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER) - return -1; - return nr_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) - 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 (NEWLY_IDLE). - * this_rq is locked. - */ -static int load_balance_newidle(int this_cpu, runqueue_t *this_rq, - struct sched_domain *sd) -{ - struct sched_group *group; - runqueue_t *busiest = NULL; - unsigned long imbalance; - int nr_moved = 0; - int sd_idle = 0; - - if (sd->flags & SD_SHARE_CPUPOWER) - sd_idle = 1; - - schedstat_inc(sd, lb_cnt[NEWLY_IDLE]); - group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE, &sd_idle); - if (!group) { - schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]); - goto out_balanced; - } - - busiest = find_busiest_queue(group, NEWLY_IDLE); - if (!busiest) { - schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]); - goto out_balanced; - } - - BUG_ON(busiest == this_rq); - - schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance); - - nr_moved = 0; - if (busiest->nr_running > 1) { - /* Attempt to move tasks */ - double_lock_balance(this_rq, busiest); - nr_moved = move_tasks(this_rq, this_cpu, busiest, - imbalance, sd, NEWLY_IDLE, NULL); - spin_unlock(&busiest->lock); - } - - if (!nr_moved) { - schedstat_inc(sd, lb_failed[NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER) - return -1; - } else - sd->nr_balance_failed = 0; - - return nr_moved; - -out_balanced: - schedstat_inc(sd, lb_balanced[NEWLY_IDLE]); - if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER) - 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, runqueue_t *this_rq) -{ - struct sched_domain *sd; - - for_each_domain(this_cpu, sd) { - if (sd->flags & SD_BALANCE_NEWIDLE) { - if (load_balance_newidle(this_cpu, this_rq, sd)) { - /* We've pulled tasks over so stop searching */ - break; - } - } - } -} - -/* - * 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(runqueue_t *busiest_rq, int busiest_cpu) -{ - struct sched_domain *sd; - runqueue_t *target_rq; - int target_cpu = busiest_rq->push_cpu; - - if (busiest_rq->nr_running <= 1) - /* no task to move */ - 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); - - /* 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 (unlikely(sd == NULL)) - goto out; - - schedstat_inc(sd, alb_cnt); - - if (move_tasks(target_rq, target_cpu, busiest_rq, 1, sd, SCHED_IDLE, NULL)) - schedstat_inc(sd, alb_pushed); - else - schedstat_inc(sd, alb_failed); -out: - spin_unlock(&target_rq->lock); -} - -/* - * rebalance_tick will get called every timer tick, on every CPU. - * - * 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. - */ - -/* Don't have all balancing operations going off at once */ -#define CPU_OFFSET(cpu) (HZ * cpu / NR_CPUS) - -static void rebalance_tick(int this_cpu, runqueue_t *this_rq, - enum idle_type idle) -{ - unsigned long old_load, this_load; - unsigned long j = jiffies + CPU_OFFSET(this_cpu); - struct sched_domain *sd; - int i; - - this_load = this_rq->nr_running * SCHED_LOAD_SCALE; - /* Update our load */ - for (i = 0; i < 3; i++) { - unsigned long new_load = this_load; - int scale = 1 << i; - old_load = this_rq->cpu_load[i]; - /* - * 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) / scale; - } - - for_each_domain(this_cpu, sd) { - unsigned long interval; - - if (!(sd->flags & SD_LOAD_BALANCE)) - continue; - - interval = sd->balance_interval; - if (idle != SCHED_IDLE) - interval *= sd->busy_factor; - - /* scale ms to jiffies */ - interval = msecs_to_jiffies(interval); - if (unlikely(!interval)) - interval = 1; - - if (j - sd->last_balance >= interval) { - if (load_balance(this_cpu, this_rq, sd, idle)) { - /* - * We've pulled tasks over so either we're no - * longer idle, or one of our SMT siblings is - * not idle. - */ - idle = NOT_IDLE; - } - sd->last_balance += interval; - } - } -} -#else -/* - * on UP we do not need to balance between CPUs: - */ -static inline void rebalance_tick(int cpu, runqueue_t *rq, enum idle_type idle) -{ -} -static inline void idle_balance(int cpu, runqueue_t *rq) -{ -} -#endif - -static inline int wake_priority_sleeper(runqueue_t *rq) -{ - int ret = 0; -#ifdef CONFIG_SCHED_SMT - spin_lock(&rq->lock); - /* - * If an SMT sibling task has been put to sleep for priority - * reasons reschedule the idle task to see if it can now run. - */ - if (rq->nr_running) { - resched_task(rq->idle); - ret = 1; - } - spin_unlock(&rq->lock); -#endif - return ret; -} - -DEFINE_PER_CPU(struct kernel_stat, kstat); - -EXPORT_PER_CPU_SYMBOL(kstat); - -/* - * This is called on clock ticks and on context switches. - * Bank in p->sched_time the ns elapsed since the last tick or switch. - */ -static inline void update_cpu_clock(task_t *p, runqueue_t *rq, - unsigned long long now) -{ - unsigned long long last = max(p->timestamp, rq->timestamp_last_tick); - p->sched_time += now - last; -} - -/* - * Return current->sched_time plus any more ns on the sched_clock - * that have not yet been banked. - */ -unsigned long long current_sched_time(const task_t *tsk) -{ - unsigned long long ns; - unsigned long flags; - local_irq_save(flags); - ns = max(tsk->timestamp, task_rq(tsk)->timestamp_last_tick); - ns = tsk->sched_time + (sched_clock() - ns); - local_irq_restore(flags); - return ns; -} - -/* - * We place interactive tasks back into the active array, if possible. - * - * To guarantee that this does not starve expired tasks we ignore the - * interactivity of a task if the first expired task had to wait more - * than a 'reasonable' amount of time. This deadline timeout is - * load-dependent, as the frequency of array switched decreases with - * increasing number of running tasks. We also ignore the interactivity - * if a better static_prio task has expired: - */ -#define EXPIRED_STARVING(rq) \ - ((STARVATION_LIMIT && ((rq)->expired_timestamp && \ - (jiffies - (rq)->expired_timestamp >= \ - STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \ - ((rq)->curr->static_prio > (rq)->best_expired_prio)) - -/* - * Account user 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 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 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; - runqueue_t *rq = this_rq(); - cputime64_t tmp; - - 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 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); - runqueue_t *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(); - runqueue_t *rq = this_rq(); - task_t *p = current; - unsigned long long now = sched_clock(); - - update_cpu_clock(p, rq, now); - - rq->timestamp_last_tick = now; - - if (p == rq->idle) { - if (wake_priority_sleeper(rq)) - goto out; - rebalance_tick(cpu, rq, SCHED_IDLE); - return; - } - - /* Task might have expired already, but not scheduled off yet */ - if (p->array != rq->active) { - set_tsk_need_resched(p); - goto out; - } - spin_lock(&rq->lock); - /* - * The task was running during this tick - update the - * time slice counter. Note: we do not update a thread's - * priority until it either goes to sleep or uses up its - * timeslice. This makes it possible for interactive tasks - * to use up their timeslices at their highest priority levels. - */ - if (rt_task(p)) { - /* - * RR tasks need a special form of timeslice management. - * FIFO tasks have no timeslices. - */ - if ((p->policy == SCHED_RR) && !--p->time_slice) { - p->time_slice = task_timeslice(p); - p->first_time_slice = 0; - set_tsk_need_resched(p); - - /* put it at the end of the queue: */ - requeue_task(p, rq->active); - } - goto out_unlock; - } - if (!--p->time_slice) { - dequeue_task(p, rq->active); - set_tsk_need_resched(p); - p->prio = effective_prio(p); - p->time_slice = task_timeslice(p); - p->first_time_slice = 0; - - if (!rq->expired_timestamp) - rq->expired_timestamp = jiffies; - if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) { - enqueue_task(p, rq->expired); - if (p->static_prio < rq->best_expired_prio) - rq->best_expired_prio = p->static_prio; - } else - enqueue_task(p, rq->active); - } else { - /* - * Prevent a too long timeslice allowing a task to monopolize - * the CPU. We do this by splitting up the timeslice into - * smaller pieces. - * - * Note: this does not mean the task's timeslices expire or - * get lost in any way, they just might be preempted by - * another task of equal priority. (one with higher - * priority would have preempted this task already.) We - * requeue this task to the end of the list on this priority - * level, which is in essence a round-robin of tasks with - * equal priority. - * - * This only applies to tasks in the interactive - * delta range with at least TIMESLICE_GRANULARITY to requeue. - */ - if (TASK_INTERACTIVE(p) && !((task_timeslice(p) - - p->time_slice) % TIMESLICE_GRANULARITY(p)) && - (p->time_slice >= TIMESLICE_GRANULARITY(p)) && - (p->array == rq->active)) { - - requeue_task(p, rq->active); - set_tsk_need_resched(p); - } - } -out_unlock: - spin_unlock(&rq->lock); -out: - rebalance_tick(cpu, rq, NOT_IDLE); -} - -#ifdef CONFIG_SCHED_SMT -static inline void wakeup_busy_runqueue(runqueue_t *rq) -{ - /* If an SMT runqueue is sleeping due to priority reasons wake it up */ - if (rq->curr == rq->idle && rq->nr_running) - resched_task(rq->idle); -} - -static void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq) -{ - struct sched_domain *tmp, *sd = NULL; - cpumask_t sibling_map; - int i; - - for_each_domain(this_cpu, tmp) - if (tmp->flags & SD_SHARE_CPUPOWER) - sd = tmp; - - if (!sd) - return; - - /* - * Unlock the current runqueue because we have to lock in - * CPU order to avoid deadlocks. Caller knows that we might - * unlock. We keep IRQs disabled. - */ - spin_unlock(&this_rq->lock); - - sibling_map = sd->span; - - for_each_cpu_mask(i, sibling_map) - spin_lock(&cpu_rq(i)->lock); - /* - * We clear this CPU from the mask. This both simplifies the - * inner loop and keps this_rq locked when we exit: - */ - cpu_clear(this_cpu, sibling_map); - - for_each_cpu_mask(i, sibling_map) { - runqueue_t *smt_rq = cpu_rq(i); - - wakeup_busy_runqueue(smt_rq); - } - - for_each_cpu_mask(i, sibling_map) - spin_unlock(&cpu_rq(i)->lock); - /* - * We exit with this_cpu's rq still held and IRQs - * still disabled: - */ -} - -/* - * number of 'lost' timeslices this task wont be able to fully - * utilize, if another task runs on a sibling. This models the - * slowdown effect of other tasks running on siblings: - */ -static inline unsigned long smt_slice(task_t *p, struct sched_domain *sd) -{ - return p->time_slice * (100 - sd->per_cpu_gain) / 100; -} - -static int dependent_sleeper(int this_cpu, runqueue_t *this_rq) -{ - struct sched_domain *tmp, *sd = NULL; - cpumask_t sibling_map; - prio_array_t *array; - int ret = 0, i; - task_t *p; - - for_each_domain(this_cpu, tmp) - if (tmp->flags & SD_SHARE_CPUPOWER) - sd = tmp; - - if (!sd) - return 0; - - /* - * The same locking rules and details apply as for - * wake_sleeping_dependent(): - */ - spin_unlock(&this_rq->lock); - sibling_map = sd->span; - for_each_cpu_mask(i, sibling_map) - spin_lock(&cpu_rq(i)->lock); - cpu_clear(this_cpu, sibling_map); - - /* - * Establish next task to be run - it might have gone away because - * we released the runqueue lock above: - */ - if (!this_rq->nr_running) - goto out_unlock; - array = this_rq->active; - if (!array->nr_active) - array = this_rq->expired; - BUG_ON(!array->nr_active); - - p = list_entry(array->queue[sched_find_first_bit(array->bitmap)].next, - task_t, run_list); - - for_each_cpu_mask(i, sibling_map) { - runqueue_t *smt_rq = cpu_rq(i); - task_t *smt_curr = smt_rq->curr; - - /* Kernel threads do not participate in dependent sleeping */ - if (!p->mm || !smt_curr->mm || rt_task(p)) - goto check_smt_task; - - /* - * If a user task with lower static priority than the - * running task on the SMT sibling is trying to schedule, - * delay it till there is proportionately less timeslice - * left of the sibling task to prevent a lower priority - * task from using an unfair proportion of the - * physical cpu's resources. -ck - */ - if (rt_task(smt_curr)) { - /* - * With real time tasks we run non-rt tasks only - * per_cpu_gain% of the time. - */ - if ((jiffies % DEF_TIMESLICE) > - (sd->per_cpu_gain * DEF_TIMESLICE / 100)) - ret = 1; - } else - if (smt_curr->static_prio < p->static_prio && - !TASK_PREEMPTS_CURR(p, smt_rq) && - smt_slice(smt_curr, sd) > task_timeslice(p)) - ret = 1; - -check_smt_task: - if ((!smt_curr->mm && smt_curr != smt_rq->idle) || - rt_task(smt_curr)) - continue; - if (!p->mm) { - wakeup_busy_runqueue(smt_rq); - continue; - } - - /* - * Reschedule a lower priority task on the SMT sibling for - * it to be put to sleep, or wake it up if it has been put to - * sleep for priority reasons to see if it should run now. - */ - if (rt_task(p)) { - if ((jiffies % DEF_TIMESLICE) > - (sd->per_cpu_gain * DEF_TIMESLICE / 100)) - resched_task(smt_curr); - } else { - if (TASK_PREEMPTS_CURR(p, smt_rq) && - smt_slice(p, sd) > task_timeslice(smt_curr)) - resched_task(smt_curr); - else - wakeup_busy_runqueue(smt_rq); - } - } -out_unlock: - for_each_cpu_mask(i, sibling_map) - spin_unlock(&cpu_rq(i)->lock); - return ret; -} -#else -static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq) -{ -} - -static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq) -{ - return 0; -} -#endif - -#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) - -void fastcall add_preempt_count(int val) -{ - /* - * Underflow? - */ - BUG_ON((preempt_count() < 0)); - preempt_count() += val; - /* - * Spinlock count overflowing soon? - */ - BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10); -} -EXPORT_SYMBOL(add_preempt_count); - -void fastcall sub_preempt_count(int val) -{ - /* - * Underflow? - */ - BUG_ON(val > preempt_count()); - /* - * Is the spinlock portion underflowing? - */ - BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK)); - preempt_count() -= val; -} -EXPORT_SYMBOL(sub_preempt_count); - -#endif - -/* - * schedule() is the main scheduler function. - */ -asmlinkage void __sched schedule(void) -{ - long *switch_count; - task_t *prev, *next; - runqueue_t *rq; - prio_array_t *array; - struct list_head *queue; - unsigned long long now; - unsigned long run_time; - int cpu, idx, new_prio; - - /* - * 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 (likely(!current->exit_state)) { - if (unlikely(in_atomic())) { - printk(KERN_ERR "scheduling while atomic: " - "%s/0x%08x/%d\n", - current->comm, preempt_count(), current->pid); - dump_stack(); - } - } - profile_hit(SCHED_PROFILING, __builtin_return_address(0)); - -need_resched: - preempt_disable(); - prev = current; - release_kernel_lock(prev); -need_resched_nonpreemptible: - rq = this_rq(); - - /* - * The idle thread is not allowed to schedule! - * Remove this check after it has been exercised a bit. - */ - if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) { - printk(KERN_ERR "bad: scheduling from the idle thread!\n"); - dump_stack(); - } - - schedstat_inc(rq, sched_cnt); - now = sched_clock(); - if (likely((long long)(now - prev->timestamp) < NS_MAX_SLEEP_AVG)) { - run_time = now - prev->timestamp; - if (unlikely((long long)(now - prev->timestamp) < 0)) - run_time = 0; - } else - run_time = NS_MAX_SLEEP_AVG; - - /* - * Tasks charged proportionately less run_time at high sleep_avg to - * delay them losing their interactive status - */ - run_time /= (CURRENT_BONUS(prev) ? : 1); - - spin_lock_irq(&rq->lock); - - if (unlikely(prev->flags & PF_DEAD)) - prev->state = EXIT_DEAD; - - switch_count = &prev->nivcsw; - if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { - switch_count = &prev->nvcsw; - if (unlikely((prev->state & TASK_INTERRUPTIBLE) && - unlikely(signal_pending(prev)))) - prev->state = TASK_RUNNING; - else { - if (prev->state == TASK_UNINTERRUPTIBLE) - rq->nr_uninterruptible++; - deactivate_task(prev, rq); - } - } - - cpu = smp_processor_id(); - if (unlikely(!rq->nr_running)) { -go_idle: - idle_balance(cpu, rq); - if (!rq->nr_running) { - next = rq->idle; - rq->expired_timestamp = 0; - wake_sleeping_dependent(cpu, rq); - /* - * wake_sleeping_dependent() might have released - * the runqueue, so break out if we got new - * tasks meanwhile: - */ - if (!rq->nr_running) - goto switch_tasks; - } - } else { - if (dependent_sleeper(cpu, rq)) { - next = rq->idle; - goto switch_tasks; - } - /* - * dependent_sleeper() releases and reacquires the runqueue - * lock, hence go into the idle loop if the rq went - * empty meanwhile: - */ - if (unlikely(!rq->nr_running)) - goto go_idle; - } - - array = rq->active; - if (unlikely(!array->nr_active)) { - /* - * Switch the active and expired arrays. - */ - schedstat_inc(rq, sched_switch); - rq->active = rq->expired; - rq->expired = array; - array = rq->active; - rq->expired_timestamp = 0; - rq->best_expired_prio = MAX_PRIO; - } - - idx = sched_find_first_bit(array->bitmap); - queue = array->queue + idx; - next = list_entry(queue->next, task_t, run_list); - - if (!rt_task(next) && next->activated > 0) { - unsigned long long delta = now - next->timestamp; - if (unlikely((long long)(now - next->timestamp) < 0)) - delta = 0; - - if (next->activated == 1) - delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128; - - array = next->array; - new_prio = recalc_task_prio(next, next->timestamp + delta); - - if (unlikely(next->prio != new_prio)) { - dequeue_task(next, array); - next->prio = new_prio; - enqueue_task(next, array); - } else - requeue_task(next, array); - } - next->activated = 0; -switch_tasks: - if (next == rq->idle) - schedstat_inc(rq, sched_goidle); - prefetch(next); - prefetch_stack(next); - clear_tsk_need_resched(prev); - rcu_qsctr_inc(task_cpu(prev)); - - update_cpu_clock(prev, rq, now); - - prev->sleep_avg -= run_time; - if ((long)prev->sleep_avg <= 0) - prev->sleep_avg = 0; - prev->timestamp = prev->last_ran = now; - - sched_info_switch(prev, next); - if (likely(prev != next)) { - next->timestamp = now; - rq->nr_switches++; - rq->curr = next; - ++*switch_count; - - prepare_task_switch(rq, next); - prev = context_switch(rq, prev, next); - 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); - } else - spin_unlock_irq(&rq->lock); - - prev = current; - if (unlikely(reacquire_kernel_lock(prev) < 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 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(); -#ifdef CONFIG_PREEMPT_BKL - struct task_struct *task = current; - int saved_lock_depth; -#endif - /* - * If there is a non-zero preempt_count or interrupts are disabled, - * we do not want to preempt the current task. Just return.. - */ - if (unlikely(ti->preempt_count || irqs_disabled())) - return; - -need_resched: - 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: - */ -#ifdef CONFIG_PREEMPT_BKL - saved_lock_depth = task->lock_depth; - task->lock_depth = -1; -#endif - schedule(); -#ifdef CONFIG_PREEMPT_BKL - task->lock_depth = saved_lock_depth; -#endif - sub_preempt_count(PREEMPT_ACTIVE); - - /* we could miss a preemption opportunity between schedule and now */ - barrier(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; -} - -EXPORT_SYMBOL(preempt_schedule); - -/* - * this is 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(); -#ifdef CONFIG_PREEMPT_BKL - struct task_struct *task = current; - int saved_lock_depth; -#endif - /* Catch callers which need to be fixed*/ - BUG_ON(ti->preempt_count || !irqs_disabled()); - -need_resched: - 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: - */ -#ifdef CONFIG_PREEMPT_BKL - saved_lock_depth = task->lock_depth; - task->lock_depth = -1; -#endif - local_irq_enable(); - schedule(); - local_irq_disable(); -#ifdef CONFIG_PREEMPT_BKL - task->lock_depth = saved_lock_depth; -#endif - sub_preempt_count(PREEMPT_ACTIVE); - - /* we could miss a preemption opportunity between schedule and now */ - barrier(); - if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) - goto need_resched; -} - -#endif /* CONFIG_PREEMPT */ - -int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, - void *key) -{ - task_t *p = curr->private; - return try_to_wake_up(p, 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) -{ - struct list_head *tmp, *next; - - list_for_each_safe(tmp, next, &q->task_list) { - wait_queue_t *curr; - unsigned flags; - curr = list_entry(tmp, wait_queue_t, task_list); - 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 fastcall __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 fastcall __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 fastcall -__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 fastcall complete(struct completion *x) -{ - unsigned long flags; - - spin_lock_irqsave(&x->wait.lock, flags); - x->done++; - __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 1, 0, NULL); - spin_unlock_irqrestore(&x->wait.lock, flags); -} -EXPORT_SYMBOL(complete); - -void fastcall 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_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, - 0, 0, NULL); - spin_unlock_irqrestore(&x->wait.lock, flags); -} -EXPORT_SYMBOL(complete_all); - -void fastcall __sched wait_for_completion(struct completion *x) -{ - might_sleep(); - spin_lock_irq(&x->wait.lock); - if (!x->done) { - DECLARE_WAITQUEUE(wait, current); - - wait.flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(&x->wait, &wait); - do { - __set_current_state(TASK_UNINTERRUPTIBLE); - spin_unlock_irq(&x->wait.lock); - schedule(); - spin_lock_irq(&x->wait.lock); - } while (!x->done); - __remove_wait_queue(&x->wait, &wait); - } - x->done--; - spin_unlock_irq(&x->wait.lock); -} -EXPORT_SYMBOL(wait_for_completion); - -unsigned long fastcall __sched -wait_for_completion_timeout(struct completion *x, unsigned long timeout) -{ - might_sleep(); - - spin_lock_irq(&x->wait.lock); - if (!x->done) { - DECLARE_WAITQUEUE(wait, current); - - wait.flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(&x->wait, &wait); - do { - __set_current_state(TASK_UNINTERRUPTIBLE); - spin_unlock_irq(&x->wait.lock); - timeout = schedule_timeout(timeout); - spin_lock_irq(&x->wait.lock); - if (!timeout) { - __remove_wait_queue(&x->wait, &wait); - goto out; - } - } while (!x->done); - __remove_wait_queue(&x->wait, &wait); - } - x->done--; -out: - spin_unlock_irq(&x->wait.lock); - return timeout; -} -EXPORT_SYMBOL(wait_for_completion_timeout); - -int fastcall __sched wait_for_completion_interruptible(struct completion *x) -{ - int ret = 0; - - might_sleep(); - - spin_lock_irq(&x->wait.lock); - if (!x->done) { - DECLARE_WAITQUEUE(wait, current); - - wait.flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(&x->wait, &wait); - do { - if (signal_pending(current)) { - ret = -ERESTARTSYS; - __remove_wait_queue(&x->wait, &wait); - goto out; - } - __set_current_state(TASK_INTERRUPTIBLE); - spin_unlock_irq(&x->wait.lock); - schedule(); - spin_lock_irq(&x->wait.lock); - } while (!x->done); - __remove_wait_queue(&x->wait, &wait); - } - x->done--; -out: - spin_unlock_irq(&x->wait.lock); - - return ret; -} -EXPORT_SYMBOL(wait_for_completion_interruptible); - -unsigned long fastcall __sched -wait_for_completion_interruptible_timeout(struct completion *x, - unsigned long timeout) -{ - might_sleep(); - - spin_lock_irq(&x->wait.lock); - if (!x->done) { - DECLARE_WAITQUEUE(wait, current); - - wait.flags |= WQ_FLAG_EXCLUSIVE; - __add_wait_queue_tail(&x->wait, &wait); - do { - if (signal_pending(current)) { - timeout = -ERESTARTSYS; - __remove_wait_queue(&x->wait, &wait); - goto out; - } - __set_current_state(TASK_INTERRUPTIBLE); - spin_unlock_irq(&x->wait.lock); - timeout = schedule_timeout(timeout); - spin_lock_irq(&x->wait.lock); - if (!timeout) { - __remove_wait_queue(&x->wait, &wait); - goto out; - } - } while (!x->done); - __remove_wait_queue(&x->wait, &wait); - } - x->done--; -out: - spin_unlock_irq(&x->wait.lock); - return timeout; -} -EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); - - -#define SLEEP_ON_VAR \ - unsigned long flags; \ - wait_queue_t wait; \ - init_waitqueue_entry(&wait, current); - -#define SLEEP_ON_HEAD \ - spin_lock_irqsave(&q->lock,flags); \ - __add_wait_queue(q, &wait); \ - spin_unlock(&q->lock); - -#define SLEEP_ON_TAIL \ - spin_lock_irq(&q->lock); \ - __remove_wait_queue(q, &wait); \ - spin_unlock_irqrestore(&q->lock, flags); - -void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) -{ - SLEEP_ON_VAR - - current->state = TASK_INTERRUPTIBLE; - - SLEEP_ON_HEAD - schedule(); - SLEEP_ON_TAIL -} - -EXPORT_SYMBOL(interruptible_sleep_on); - -long fastcall __sched -interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) -{ - SLEEP_ON_VAR - - current->state = TASK_INTERRUPTIBLE; - - SLEEP_ON_HEAD - timeout = schedule_timeout(timeout); - SLEEP_ON_TAIL - - return timeout; -} - -EXPORT_SYMBOL(interruptible_sleep_on_timeout); - -void fastcall __sched sleep_on(wait_queue_head_t *q) -{ - SLEEP_ON_VAR - - current->state = TASK_UNINTERRUPTIBLE; - - SLEEP_ON_HEAD - schedule(); - SLEEP_ON_TAIL -} - -EXPORT_SYMBOL(sleep_on); - -long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) -{ - SLEEP_ON_VAR - - current->state = TASK_UNINTERRUPTIBLE; - - SLEEP_ON_HEAD - timeout = schedule_timeout(timeout); - SLEEP_ON_TAIL - - return timeout; -} - -EXPORT_SYMBOL(sleep_on_timeout); - -void set_user_nice(task_t *p, long nice) -{ - unsigned long flags; - prio_array_t *array; - runqueue_t *rq; - int old_prio, new_prio, delta; - - 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); - /* - * The RT priorities are set via sched_setscheduler(), but we still - * allow the 'normal' nice value to be set - but as expected - * it wont have any effect on scheduling until the task is - * not SCHED_NORMAL/SCHED_BATCH: - */ - if (rt_task(p)) { - p->static_prio = NICE_TO_PRIO(nice); - goto out_unlock; - } - array = p->array; - if (array) { - dequeue_task(p, array); - dec_prio_bias(rq, p->static_prio); - } - - old_prio = p->prio; - new_prio = NICE_TO_PRIO(nice); - delta = new_prio - old_prio; - p->static_prio = NICE_TO_PRIO(nice); - p->prio += delta; - - if (array) { - enqueue_task(p, array); - inc_prio_bias(rq, p->static_prio); - /* - * 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 task_t *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) -{ - int retval; - long nice; - - /* - * 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 task_t *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 task_t *p) -{ - return TASK_NICE(p); -} -EXPORT_SYMBOL_GPL(task_nice); - -/** - * idle_cpu - is a given cpu idle currently? - * @cpu: the processor in question. - */ -int idle_cpu(int cpu) -{ - return cpu_curr(cpu) == cpu_rq(cpu)->idle; -} - -/** - * idle_task - return the idle task for a given cpu. - * @cpu: the processor in question. - */ -task_t *idle_task(int cpu) -{ - return cpu_rq(cpu)->idle; -} - -/** - * find_process_by_pid - find a process with a matching PID value. - * @pid: the pid in question. - */ -static inline task_t *find_process_by_pid(pid_t pid) -{ - return pid ? find_task_by_pid(pid) : current; -} - -/* Actually do priority change: must hold rq lock. */ -static void __setscheduler(struct task_struct *p, int policy, int prio) -{ - BUG_ON(p->array); - p->policy = policy; - p->rt_priority = prio; - if (policy != SCHED_NORMAL && policy != SCHED_BATCH) { - p->prio = MAX_RT_PRIO-1 - p->rt_priority; - } else { - p->prio = p->static_prio; - /* - * SCHED_BATCH tasks are treated as perpetual CPU hogs: - */ - if (policy == SCHED_BATCH) - p->sleep_avg = 0; - } -} - -/** - * sched_setscheduler - change the scheduling policy and/or RT priority of - * a thread. - * @p: the task in question. - * @policy: new policy. - * @param: structure containing the new RT priority. - */ -int sched_setscheduler(struct task_struct *p, int policy, - struct sched_param *param) -{ - int retval; - int oldprio, oldpolicy = -1; - prio_array_t *array; - unsigned long flags; - runqueue_t *rq; - -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) - return -EINVAL; - /* - * Valid priorities for SCHED_FIFO and SCHED_RR are - * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and - * SCHED_BATCH is 0. - */ - if (param->sched_priority < 0 || - (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || - (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) - return -EINVAL; - if ((policy == SCHED_NORMAL || policy == SCHED_BATCH) - != (param->sched_priority == 0)) - return -EINVAL; - - /* - * Allow unprivileged RT tasks to decrease priority: - */ - if (!capable(CAP_SYS_NICE)) { - /* - * can't change policy, except between SCHED_NORMAL - * and SCHED_BATCH: - */ - if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) && - (policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) && - !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) - return -EPERM; - /* can't increase priority */ - if ((policy != SCHED_NORMAL && policy != SCHED_BATCH) && - param->sched_priority > p->rt_priority && - param->sched_priority > - p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) - return -EPERM; - /* can't change other user's priorities */ - if ((current->euid != p->euid) && - (current->euid != p->uid)) - return -EPERM; - } - - retval = security_task_setscheduler(p, policy, param); - if (retval) - return retval; - /* - * To be able to change p->policy safely, the apropriate - * runqueue lock must be held. - */ - rq = task_rq_lock(p, &flags); - /* recheck policy now with rq lock held */ - if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { - policy = oldpolicy = -1; - task_rq_unlock(rq, &flags); - goto recheck; - } - array = p->array; - if (array) - deactivate_task(p, rq); - oldprio = p->prio; - __setscheduler(p, policy, param->sched_priority); - if (array) { - __activate_task(p, rq); - /* - * Reschedule if we are currently running on this runqueue and - * our priority decreased, or if we are not currently running on - * this runqueue and our priority is higher than the current's - */ - if (task_running(rq, p)) { - if (p->prio > oldprio) - resched_task(rq->curr); - } else if (TASK_PREEMPTS_CURR(p, rq)) - resched_task(rq->curr); - } - task_rq_unlock(rq, &flags); - return 0; -} -EXPORT_SYMBOL_GPL(sched_setscheduler); - -static int -do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) -{ - int retval; - struct sched_param lparam; - struct task_struct *p; - - if (!param || pid < 0) - return -EINVAL; - if (copy_from_user(&lparam, param, sizeof(struct sched_param))) - return -EFAULT; - read_lock_irq(&tasklist_lock); - p = find_process_by_pid(pid); - if (!p) { - read_unlock_irq(&tasklist_lock); - return -ESRCH; - } - retval = sched_setscheduler(p, policy, &lparam); - read_unlock_irq(&tasklist_lock); - 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) -{ - int retval = -EINVAL; - task_t *p; - - if (pid < 0) - goto out_nounlock; - - 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); - -out_nounlock: - return retval; -} - -/** - * sys_sched_getscheduler - get the RT priority of a thread - * @pid: the pid in question. - * @param: structure containing the RT priority. - */ -asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) -{ - struct sched_param lp; - int retval = -EINVAL; - task_t *p; - - if (!param || pid < 0) - goto out_nounlock; - - 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; - -out_nounlock: - return retval; - -out_unlock: - read_unlock(&tasklist_lock); - return retval; -} - -long sched_setaffinity(pid_t pid, cpumask_t new_mask) -{ - task_t *p; - int retval; - cpumask_t cpus_allowed; - - lock_cpu_hotplug(); - read_lock(&tasklist_lock); - - p = find_process_by_pid(pid); - if (!p) { - read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); - 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; - - cpus_allowed = cpuset_cpus_allowed(p); - cpus_and(new_mask, new_mask, cpus_allowed); - retval = set_cpus_allowed(p, new_mask); - -out_unlock: - put_task_struct(p); - unlock_cpu_hotplug(); - 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; -cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; -#endif - -long sched_getaffinity(pid_t pid, cpumask_t *mask) -{ - int retval; - task_t *p; - - lock_cpu_hotplug(); - read_lock(&tasklist_lock); - - retval = -ESRCH; - p = find_process_by_pid(pid); - if (!p) - goto out_unlock; - - retval = 0; - cpus_and(*mask, p->cpus_allowed, cpu_possible_map); - -out_unlock: - read_unlock(&tasklist_lock); - unlock_cpu_hotplug(); - if (retval) - return retval; - - return 0; -} - -/** - * 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 by moving the calling thread - * to the expired array. If there are no other threads running on this - * CPU then this function will return. - */ -asmlinkage long sys_sched_yield(void) -{ - runqueue_t *rq = this_rq_lock(); - prio_array_t *array = current->array; - prio_array_t *target = rq->expired; - - schedstat_inc(rq, yld_cnt); - /* - * We implement yielding by moving the task into the expired - * queue. - * - * (special rule: RT tasks will just roundrobin in the active - * array.) - */ - if (rt_task(current)) - target = rq->active; - - if (array->nr_active == 1) { - schedstat_inc(rq, yld_act_empty); - if (!rq->expired->nr_active) - schedstat_inc(rq, yld_both_empty); - } else if (!rq->expired->nr_active) - schedstat_inc(rq, yld_exp_empty); - - if (array != target) { - dequeue_task(current, array); - enqueue_task(current, target); - } else - /* - * requeue_task is cheaper so perform that if possible. - */ - requeue_task(current, array); - - /* - * Since we are going to call schedule() anyway, there's - * no need to preempt or enable interrupts: - */ - __release(rq->lock); - _raw_spin_unlock(&rq->lock); - preempt_enable_no_resched(); - - schedule(); - - return 0; -} - -static inline void __cond_resched(void) -{ - /* - * The BKS might be reacquired before we have dropped - * PREEMPT_ACTIVE, which could trigger a second - * cond_resched() call. - */ - if (unlikely(preempt_count())) - return; - do { - add_preempt_count(PREEMPT_ACTIVE); - schedule(); - sub_preempt_count(PREEMPT_ACTIVE); - } while (need_resched()); -} - -int __sched cond_resched(void) -{ - if (need_resched()) { - __cond_resched(); - return 1; - } - return 0; -} - -EXPORT_SYMBOL(cond_resched); - -/* - * cond_resched_lock() - if a reschedule is pending, drop the given lock, - * call schedule, and on return reacquire the lock. - * - * This works OK both with and without CONFIG_PREEMPT. We do strange low-level - * operations here to prevent schedule() from being called twice (once via - * spin_unlock(), once by hand). - */ -int cond_resched_lock(spinlock_t *lock) -{ - int ret = 0; - - if (need_lockbreak(lock)) { - spin_unlock(lock); - cpu_relax(); - ret = 1; - spin_lock(lock); - } - if (need_resched()) { - _raw_spin_unlock(lock); - preempt_enable_no_resched(); - __cond_resched(); - 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()) { - __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 runqueue *rq = &per_cpu(runqueues, raw_smp_processor_id()); - - atomic_inc(&rq->nr_iowait); - schedule(); - atomic_dec(&rq->nr_iowait); -} - -EXPORT_SYMBOL(io_schedule); - -long __sched io_schedule_timeout(long timeout) -{ - struct runqueue *rq = &per_cpu(runqueues, raw_smp_processor_id()); - long ret; - - atomic_inc(&rq->nr_iowait); - ret = schedule_timeout(timeout); - atomic_dec(&rq->nr_iowait); - 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: - 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: - 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) -{ - int retval = -EINVAL; - struct timespec t; - task_t *p; - - if (pid < 0) - goto out_nounlock; - - 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; - - jiffies_to_timespec(p->policy & SCHED_FIFO ? - 0 : task_timeslice(p), &t); - read_unlock(&tasklist_lock); - retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; -out_nounlock: - return retval; -out_unlock: - read_unlock(&tasklist_lock); - return retval; -} - -static inline struct task_struct *eldest_child(struct task_struct *p) -{ - if (list_empty(&p->children)) return NULL; - return list_entry(p->children.next,struct task_struct,sibling); -} - -static inline struct task_struct *older_sibling(struct task_struct *p) -{ - if (p->sibling.prev==&p->parent->children) return NULL; - return list_entry(p->sibling.prev,struct task_struct,sibling); -} - -static inline struct task_struct *younger_sibling(struct task_struct *p) -{ - if (p->sibling.next==&p->parent->children) return NULL; - return list_entry(p->sibling.next,struct task_struct,sibling); -} - -static void show_task(task_t *p) -{ - task_t *relative; - unsigned state; - unsigned long free = 0; - static const char *stat_nam[] = { "R", "S", "D", "T", "t", "Z", "X" }; - - printk("%-13.13s ", p->comm); - state = p->state ? __ffs(p->state) + 1 : 0; - if (state < ARRAY_SIZE(stat_nam)) - printk(stat_nam[state]); - else - printk("?"); -#if (BITS_PER_LONG == 32) - if (state == TASK_RUNNING) - printk(" running "); - else - printk(" %08lX ", thread_saved_pc(p)); -#else - if (state == TASK_RUNNING) - printk(" running task "); - else - printk(" %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("%5lu %5d %6d ", free, p->pid, p->parent->pid); - if ((relative = eldest_child(p))) - printk("%5d ", relative->pid); - else - printk(" "); - if ((relative = younger_sibling(p))) - printk("%7d", relative->pid); - else - printk(" "); - if ((relative = older_sibling(p))) - printk(" %5d", relative->pid); - else - printk(" "); - if (!p->mm) - printk(" (L-TLB)\n"); - else - printk(" (NOTLB)\n"); - - if (state != TASK_RUNNING) - show_stack(p, NULL); -} - -void show_state(void) -{ - task_t *g, *p; - -#if (BITS_PER_LONG == 32) - printk("\n" - " sibling\n"); - printk(" task PC pid father child younger older\n"); -#else - printk("\n" - " sibling\n"); - printk(" task PC pid father child younger older\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(); - show_task(p); - } while_each_thread(g, p); - - read_unlock(&tasklist_lock); - mutex_debug_show_all_locks(); -} - -/** - * 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 __devinit init_idle(task_t *idle, int cpu) -{ - runqueue_t *rq = cpu_rq(cpu); - unsigned long flags; - - idle->sleep_avg = 0; - idle->array = NULL; - idle->prio = MAX_PRIO; - idle->state = TASK_RUNNING; - 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! */ -#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) - task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); -#else - task_thread_info(idle)->preempt_count = 0; -#endif -} - -/* - * 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; - -#ifdef CONFIG_SMP -/* - * This is how migration works: - * - * 1) we queue a migration_req_t 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(task_t *p, cpumask_t new_mask) -{ - unsigned long flags; - int ret = 0; - migration_req_t req; - runqueue_t *rq; - - rq = task_rq_lock(p, &flags); - if (!cpus_intersects(new_mask, cpu_online_map)) { - ret = -EINVAL; - goto out; - } - - p->cpus_allowed = 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. - */ -static void __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) -{ - runqueue_t *rq_dest, *rq_src; - - if (unlikely(cpu_is_offline(dest_cpu))) - return; - - 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; - - set_task_cpu(p, dest_cpu); - if (p->array) { - /* - * Sync timestamp with rq_dest's before activating. - * The same thing could be achieved by doing this step - * afterwards, and pretending it was a local activate. - * This way is cleaner and logically correct. - */ - p->timestamp = p->timestamp - rq_src->timestamp_last_tick - + rq_dest->timestamp_last_tick; - deactivate_task(p, rq_src); - activate_task(p, rq_dest, 0); - if (TASK_PREEMPTS_CURR(p, rq_dest)) - resched_task(rq_dest->curr); - } - -out: - double_rq_unlock(rq_src, rq_dest); -} - -/* - * 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) -{ - runqueue_t *rq; - int cpu = (long)data; - - rq = cpu_rq(cpu); - BUG_ON(rq->migration_thread != current); - - set_current_state(TASK_INTERRUPTIBLE); - while (!kthread_should_stop()) { - struct list_head *head; - migration_req_t *req; - - try_to_freeze(); - - 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, migration_req_t, 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 -/* Figure out where task on dead CPU should go, use force if neccessary. */ -static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *tsk) -{ - int dest_cpu; - cpumask_t mask; - - /* On same node? */ - mask = node_to_cpumask(cpu_to_node(dead_cpu)); - cpus_and(mask, mask, tsk->cpus_allowed); - dest_cpu = any_online_cpu(mask); - - /* On any allowed CPU? */ - if (dest_cpu == NR_CPUS) - dest_cpu = any_online_cpu(tsk->cpus_allowed); - - /* No more Mr. Nice Guy. */ - if (dest_cpu == NR_CPUS) { - cpus_setall(tsk->cpus_allowed); - dest_cpu = any_online_cpu(tsk->cpus_allowed); - - /* - * Don't tell them about moving exiting tasks or - * kernel threads (both mm NULL), since they never - * leave kernel. - */ - if (tsk->mm && printk_ratelimit()) - printk(KERN_INFO "process %d (%s) no " - "longer affine to cpu%d\n", - tsk->pid, tsk->comm, dead_cpu); - } - __migrate_task(tsk, 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(runqueue_t *rq_src) -{ - runqueue_t *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 *tsk, *t; - - write_lock_irq(&tasklist_lock); - - do_each_thread(t, tsk) { - if (tsk == current) - continue; - - if (task_cpu(tsk) == src_cpu) - move_task_off_dead_cpu(src_cpu, tsk); - } while_each_thread(t, tsk); - - write_unlock_irq(&tasklist_lock); -} - -/* Schedules idle task to be the next runnable task on current CPU. - * It does so by boosting its priority to highest possible and adding it to - * the _front_ of runqueue. Used by CPU offline code. - */ -void sched_idle_next(void) -{ - int cpu = smp_processor_id(); - runqueue_t *rq = this_rq(); - struct task_struct *p = rq->idle; - unsigned long flags; - - /* cpu has to be offline */ - BUG_ON(cpu_online(cpu)); - - /* Strictly not necessary since rest of the CPUs are stopped by now - * and interrupts disabled on current cpu. - */ - spin_lock_irqsave(&rq->lock, flags); - - __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); - /* Add idle task to _front_ of it's priority queue */ - __activate_idle_task(p, rq); - - 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); -} - -static void migrate_dead(unsigned int dead_cpu, task_t *tsk) -{ - struct runqueue *rq = cpu_rq(dead_cpu); - - /* Must be exiting, otherwise would be on tasklist. */ - BUG_ON(tsk->exit_state != EXIT_ZOMBIE && tsk->exit_state != EXIT_DEAD); - - /* Cannot have done final schedule yet: would have vanished. */ - BUG_ON(tsk->flags & PF_DEAD); - - get_task_struct(tsk); - - /* - * 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, tsk); - spin_lock_irq(&rq->lock); - - put_task_struct(tsk); -} - -/* release_task() removes task from tasklist, so we won't find dead tasks. */ -static void migrate_dead_tasks(unsigned int dead_cpu) -{ - unsigned arr, i; - struct runqueue *rq = cpu_rq(dead_cpu); - - for (arr = 0; arr < 2; arr++) { - for (i = 0; i < MAX_PRIO; i++) { - struct list_head *list = &rq->arrays[arr].queue[i]; - while (!list_empty(list)) - migrate_dead(dead_cpu, - list_entry(list->next, task_t, - run_list)); - } - } -} -#endif /* CONFIG_HOTPLUG_CPU */ - -/* - * 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 migration_call(struct notifier_block *nfb, unsigned long action, - void *hcpu) -{ - int cpu = (long)hcpu; - struct task_struct *p; - struct runqueue *rq; - unsigned long flags; - - switch (action) { - case CPU_UP_PREPARE: - p = kthread_create(migration_thread, hcpu, "migration/%d",cpu); - if (IS_ERR(p)) - return NOTIFY_BAD; - p->flags |= PF_NOFREEZE; - kthread_bind(p, cpu); - /* Must be high prio: stop_machine expects to yield to it. */ - rq = task_rq_lock(p, &flags); - __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); - task_rq_unlock(rq, &flags); - cpu_rq(cpu)->migration_thread = p; - break; - case CPU_ONLINE: - /* Strictly unneccessary, as first user will wake it. */ - wake_up_process(cpu_rq(cpu)->migration_thread); - break; -#ifdef CONFIG_HOTPLUG_CPU - case CPU_UP_CANCELED: - /* 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: - 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) */ - rq = task_rq_lock(rq->idle, &flags); - deactivate_task(rq->idle, rq); - rq->idle->static_prio = MAX_PRIO; - __setscheduler(rq->idle, SCHED_NORMAL, 0); - migrate_dead_tasks(cpu); - task_rq_unlock(rq, &flags); - migrate_nr_uninterruptible(rq); - BUG_ON(rq->nr_running != 0); - - /* No need to migrate the tasks: it was best-effort if - * they didn't do lock_cpu_hotplug(). Just wake up - * the requestors. */ - spin_lock_irq(&rq->lock); - while (!list_empty(&rq->migration_queue)) { - migration_req_t *req; - req = list_entry(rq->migration_queue.next, - migration_req_t, list); - list_del_init(&req->list); - complete(&req->done); - } - spin_unlock_irq(&rq->lock); - break; -#endif - } - return NOTIFY_OK; -} - -/* Register at highest priority so that task migration (migrate_all_tasks) - * happens before everything else. - */ -static struct notifier_block __devinitdata migration_notifier = { - .notifier_call = migration_call, - .priority = 10 -}; - -int __init migration_init(void) -{ - void *cpu = (void *)(long)smp_processor_id(); - /* Start one for boot CPU. */ - migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); - migration_call(&migration_notifier, CPU_ONLINE, cpu); - register_cpu_notifier(&migration_notifier); - return 0; -} -#endif - -#ifdef CONFIG_SMP -#undef SCHED_DOMAIN_DEBUG -#ifdef SCHED_DOMAIN_DEBUG -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); - - do { - int i; - char str[NR_CPUS]; - struct sched_group *group = sd->groups; - cpumask_t groupmask; - - cpumask_scnprintf(str, NR_CPUS, sd->span); - cpus_clear(groupmask); - - printk(KERN_DEBUG); - for (i = 0; i < level + 1; i++) - printk(" "); - printk("domain %d: ", 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"); - break; - } - - printk("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); - for (i = 0; i < level + 2; i++) - printk(" "); - printk("groups:"); - do { - if (!group) { - printk("\n"); - printk(KERN_ERR "ERROR: group is NULL\n"); - break; - } - - if (!group->cpu_power) { - printk("\n"); - printk(KERN_ERR "ERROR: domain->cpu_power not set\n"); - } - - if (!cpus_weight(group->cpumask)) { - printk("\n"); - printk(KERN_ERR "ERROR: empty group\n"); - } - - if (cpus_intersects(groupmask, group->cpumask)) { - printk("\n"); - printk(KERN_ERR "ERROR: repeated CPUs\n"); - } - - cpus_or(groupmask, groupmask, group->cpumask); - - cpumask_scnprintf(str, NR_CPUS, group->cpumask); - printk(" %s", str); - - group = group->next; - } while (group != sd->groups); - printk("\n"); - - if (!cpus_equal(sd->span, groupmask)) - printk(KERN_ERR "ERROR: groups don't span domain->span\n"); - - level++; - sd = sd->parent; - - if (sd) { - if (!cpus_subset(groupmask, sd->span)) - printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n"); - } - - } while (sd); -} -#else -#define sched_domain_debug(sd, cpu) {} -#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)) { - 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); - } - if (~cflags & pflags) - return 0; - - return 1; -} - -/* - * 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, int cpu) -{ - runqueue_t *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 (sd && sd_degenerate(sd)) - sd = sd->parent; - - sched_domain_debug(sd, cpu); - - rcu_assign_pointer(rq->sd, sd); -} - -/* cpus with isolated domains */ -static cpumask_t __devinitdata 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 an array of groups, the cpumask we wish - * to span, and a pointer to a function which identifies what group a CPU - * belongs to. The return value of group_fn must be a valid index into the - * groups[] array, and must be >= 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(struct sched_group groups[], cpumask_t span, - int (*group_fn)(int cpu)) -{ - struct sched_group *first = NULL, *last = NULL; - cpumask_t covered = CPU_MASK_NONE; - int i; - - for_each_cpu_mask(i, span) { - int group = group_fn(i); - struct sched_group *sg = &groups[group]; - 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) != 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 - -/* - * Self-tuning task migration cost measurement between source and target CPUs. - * - * This is done by measuring the cost of manipulating buffers of varying - * sizes. For a given buffer-size here are the steps that are taken: - * - * 1) the source CPU reads+dirties a shared buffer - * 2) the target CPU reads+dirties the same shared buffer - * - * We measure how long they take, in the following 4 scenarios: - * - * - source: CPU1, target: CPU2 | cost1 - * - source: CPU2, target: CPU1 | cost2 - * - source: CPU1, target: CPU1 | cost3 - * - source: CPU2, target: CPU2 | cost4 - * - * We then calculate the cost3+cost4-cost1-cost2 difference - this is - * the cost of migration. - * - * We then start off from a small buffer-size and iterate up to larger - * buffer sizes, in 5% steps - measuring each buffer-size separately, and - * doing a maximum search for the cost. (The maximum cost for a migration - * normally occurs when the working set size is around the effective cache - * size.) - */ -#define SEARCH_SCOPE 2 -#define MIN_CACHE_SIZE (64*1024U) -#define DEFAULT_CACHE_SIZE (5*1024*1024U) -#define ITERATIONS 2 -#define SIZE_THRESH 130 -#define COST_THRESH 130 - -/* - * The migration cost is a function of 'domain distance'. Domain - * distance is the number of steps a CPU has to iterate down its - * domain tree to share a domain with the other CPU. The farther - * two CPUs are from each other, the larger the distance gets. - * - * Note that we use the distance only to cache measurement results, - * the distance value is not used numerically otherwise. When two - * CPUs have the same distance it is assumed that the migration - * cost is the same. (this is a simplification but quite practical) - */ -#define MAX_DOMAIN_DISTANCE 32 - -static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] = - { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = -1LL }; - -/* - * Allow override of migration cost - in units of microseconds. - * E.g. migration_cost=1000,2000,3000 will set up a level-1 cost - * of 1 msec, level-2 cost of 2 msecs and level3 cost of 3 msecs: - */ -static int __init migration_cost_setup(char *str) -{ - int ints[MAX_DOMAIN_DISTANCE+1], i; - - str = get_options(str, ARRAY_SIZE(ints), ints); - - printk("#ints: %d\n", ints[0]); - for (i = 1; i <= ints[0]; i++) { - migration_cost[i-1] = (unsigned long long)ints[i]*1000; - printk("migration_cost[%d]: %Ld\n", i-1, migration_cost[i-1]); - } - return 1; -} - -__setup ("migration_cost=", migration_cost_setup); - -/* - * Global multiplier (divisor) for migration-cutoff values, - * in percentiles. E.g. use a value of 150 to get 1.5 times - * longer cache-hot cutoff times. - * - * (We scale it from 100 to 128 to long long handling easier.) - */ - -#define MIGRATION_FACTOR_SCALE 128 - -static unsigned int migration_factor = MIGRATION_FACTOR_SCALE; - -static int __init setup_migration_factor(char *str) -{ - get_option(&str, &migration_factor); - migration_factor = migration_factor * MIGRATION_FACTOR_SCALE / 100; - return 1; -} - -__setup("migration_factor=", setup_migration_factor); - -/* - * Estimated distance of two CPUs, measured via the number of domains - * we have to pass for the two CPUs to be in the same span: - */ -static unsigned long domain_distance(int cpu1, int cpu2) -{ - unsigned long distance = 0; - struct sched_domain *sd; - - for_each_domain(cpu1, sd) { - WARN_ON(!cpu_isset(cpu1, sd->span)); - if (cpu_isset(cpu2, sd->span)) - return distance; - distance++; - } - if (distance >= MAX_DOMAIN_DISTANCE) { - WARN_ON(1); - distance = MAX_DOMAIN_DISTANCE-1; - } - - return distance; -} - -static unsigned int migration_debug; - -static int __init setup_migration_debug(char *str) -{ - get_option(&str, &migration_debug); - return 1; -} - -__setup("migration_debug=", setup_migration_debug); - -/* - * Maximum cache-size that the scheduler should try to measure. - * Architectures with larger caches should tune this up during - * bootup. Gets used in the domain-setup code (i.e. during SMP - * bootup). - */ -unsigned int max_cache_size; - -static int __init setup_max_cache_size(char *str) -{ - get_option(&str, &max_cache_size); - return 1; -} - -__setup("max_cache_size=", setup_max_cache_size); - -/* - * Dirty a big buffer in a hard-to-predict (for the L2 cache) way. This - * is the operation that is timed, so we try to generate unpredictable - * cachemisses that still end up filling the L2 cache: - */ -static void touch_cache(void *__cache, unsigned long __size) -{ - unsigned long size = __size/sizeof(long), chunk1 = size/3, - chunk2 = 2*size/3; - unsigned long *cache = __cache; - int i; - - for (i = 0; i < size/6; i += 8) { - switch (i % 6) { - case 0: cache[i]++; - case 1: cache[size-1-i]++; - case 2: cache[chunk1-i]++; - case 3: cache[chunk1+i]++; - case 4: cache[chunk2-i]++; - case 5: cache[chunk2+i]++; - } - } -} - -/* - * Measure the cache-cost of one task migration. Returns in units of nsec. - */ -static unsigned long long measure_one(void *cache, unsigned long size, - int source, int target) -{ - cpumask_t mask, saved_mask; - unsigned long long t0, t1, t2, t3, cost; - - saved_mask = current->cpus_allowed; - - /* - * Flush source caches to RAM and invalidate them: - */ - sched_cacheflush(); - - /* - * Migrate to the source CPU: - */ - mask = cpumask_of_cpu(source); - set_cpus_allowed(current, mask); - WARN_ON(smp_processor_id() != source); - - /* - * Dirty the working set: - */ - t0 = sched_clock(); - touch_cache(cache, size); - t1 = sched_clock(); - - /* - * Migrate to the target CPU, dirty the L2 cache and access - * the shared buffer. (which represents the working set - * of a migrated task.) - */ - mask = cpumask_of_cpu(target); - set_cpus_allowed(current, mask); - WARN_ON(smp_processor_id() != target); - - t2 = sched_clock(); - touch_cache(cache, size); - t3 = sched_clock(); - - cost = t1-t0 + t3-t2; - - if (migration_debug >= 2) - printk("[%d->%d]: %8Ld %8Ld %8Ld => %10Ld.\n", - source, target, t1-t0, t1-t0, t3-t2, cost); - /* - * Flush target caches to RAM and invalidate them: - */ - sched_cacheflush(); - - set_cpus_allowed(current, saved_mask); - - return cost; -} - -/* - * Measure a series of task migrations and return the average - * result. Since this code runs early during bootup the system - * is 'undisturbed' and the average latency makes sense. - * - * The algorithm in essence auto-detects the relevant cache-size, - * so it will properly detect different cachesizes for different - * cache-hierarchies, depending on how the CPUs are connected. - * - * Architectures can prime the upper limit of the search range via - * max_cache_size, otherwise the search range defaults to 20MB...64K. - */ -static unsigned long long -measure_cost(int cpu1, int cpu2, void *cache, unsigned int size) -{ - unsigned long long cost1, cost2; - int i; - - /* - * Measure the migration cost of 'size' bytes, over an - * average of 10 runs: - * - * (We perturb the cache size by a small (0..4k) - * value to compensate size/alignment related artifacts. - * We also subtract the cost of the operation done on - * the same CPU.) - */ - cost1 = 0; - - /* - * dry run, to make sure we start off cache-cold on cpu1, - * and to get any vmalloc pagefaults in advance: - */ - measure_one(cache, size, cpu1, cpu2); - for (i = 0; i < ITERATIONS; i++) - cost1 += measure_one(cache, size - i*1024, cpu1, cpu2); - - measure_one(cache, size, cpu2, cpu1); - for (i = 0; i < ITERATIONS; i++) - cost1 += measure_one(cache, size - i*1024, cpu2, cpu1); - - /* - * (We measure the non-migrating [cached] cost on both - * cpu1 and cpu2, to handle CPUs with different speeds) - */ - cost2 = 0; - - measure_one(cache, size, cpu1, cpu1); - for (i = 0; i < ITERATIONS; i++) - cost2 += measure_one(cache, size - i*1024, cpu1, cpu1); - - measure_one(cache, size, cpu2, cpu2); - for (i = 0; i < ITERATIONS; i++) - cost2 += measure_one(cache, size - i*1024, cpu2, cpu2); - - /* - * Get the per-iteration migration cost: - */ - do_div(cost1, 2*ITERATIONS); - do_div(cost2, 2*ITERATIONS); - - return cost1 - cost2; -} - -static unsigned long long measure_migration_cost(int cpu1, int cpu2) -{ - unsigned long long max_cost = 0, fluct = 0, avg_fluct = 0; - unsigned int max_size, size, size_found = 0; - long long cost = 0, prev_cost; - void *cache; - - /* - * Search from max_cache_size*5 down to 64K - the real relevant - * cachesize has to lie somewhere inbetween. - */ - if (max_cache_size) { - max_size = max(max_cache_size * SEARCH_SCOPE, MIN_CACHE_SIZE); - size = max(max_cache_size / SEARCH_SCOPE, MIN_CACHE_SIZE); - } else { - /* - * Since we have no estimation about the relevant - * search range - */ - max_size = DEFAULT_CACHE_SIZE * SEARCH_SCOPE; - size = MIN_CACHE_SIZE; - } - - if (!cpu_online(cpu1) || !cpu_online(cpu2)) { - printk("cpu %d and %d not both online!\n", cpu1, cpu2); - return 0; - } - - /* - * Allocate the working set: - */ - cache = vmalloc(max_size); - if (!cache) { - printk("could not vmalloc %d bytes for cache!\n", 2*max_size); - return 1000000; // return 1 msec on very small boxen - } - - while (size <= max_size) { - prev_cost = cost; - cost = measure_cost(cpu1, cpu2, cache, size); - - /* - * Update the max: - */ - if (cost > 0) { - if (max_cost < cost) { - max_cost = cost; - size_found = size; - } - } - /* - * Calculate average fluctuation, we use this to prevent - * noise from triggering an early break out of the loop: - */ - fluct = abs(cost - prev_cost); - avg_fluct = (avg_fluct + fluct)/2; - - if (migration_debug) - printk("-> [%d][%d][%7d] %3ld.%ld [%3ld.%ld] (%ld): (%8Ld %8Ld)\n", - cpu1, cpu2, size, - (long)cost / 1000000, - ((long)cost / 100000) % 10, - (long)max_cost / 1000000, - ((long)max_cost / 100000) % 10, - domain_distance(cpu1, cpu2), - cost, avg_fluct); - - /* - * If we iterated at least 20% past the previous maximum, - * and the cost has dropped by more than 20% already, - * (taking fluctuations into account) then we assume to - * have found the maximum and break out of the loop early: - */ - if (size_found && (size*100 > size_found*SIZE_THRESH)) - if (cost+avg_fluct <= 0 || - max_cost*100 > (cost+avg_fluct)*COST_THRESH) { - - if (migration_debug) - printk("-> found max.\n"); - break; - } - /* - * Increase the cachesize in 5% steps: - */ - size = size * 20 / 19; - } - - if (migration_debug) - printk("[%d][%d] working set size found: %d, cost: %Ld\n", - cpu1, cpu2, size_found, max_cost); - - vfree(cache); - - /* - * A task is considered 'cache cold' if at least 2 times - * the worst-case cost of migration has passed. - * - * (this limit is only listened to if the load-balancing - * situation is 'nice' - if there is a large imbalance we - * ignore it for the sake of CPU utilization and - * processing fairness.) - */ - return 2 * max_cost * migration_factor / MIGRATION_FACTOR_SCALE; -} - -static void calibrate_migration_costs(const cpumask_t *cpu_map) -{ - int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = raw_smp_processor_id(); - unsigned long j0, j1, distance, max_distance = 0; - struct sched_domain *sd; - - j0 = jiffies; - - /* - * First pass - calculate the cacheflush times: - */ - for_each_cpu_mask(cpu1, *cpu_map) { - for_each_cpu_mask(cpu2, *cpu_map) { - if (cpu1 == cpu2) - continue; - distance = domain_distance(cpu1, cpu2); - max_distance = max(max_distance, distance); - /* - * No result cached yet? - */ - if (migration_cost[distance] == -1LL) - migration_cost[distance] = - measure_migration_cost(cpu1, cpu2); - } - } - /* - * Second pass - update the sched domain hierarchy with - * the new cache-hot-time estimations: - */ - for_each_cpu_mask(cpu, *cpu_map) { - distance = 0; - for_each_domain(cpu, sd) { - sd->cache_hot_time = migration_cost[distance]; - distance++; - } - } - /* - * Print the matrix: - */ - if (migration_debug) - printk("migration: max_cache_size: %d, cpu: %d MHz:\n", - max_cache_size, -#ifdef CONFIG_X86 - cpu_khz/1000 -#else - -1 -#endif - ); - printk("migration_cost="); - for (distance = 0; distance <= max_distance; distance++) { - if (distance) - printk(","); - printk("%ld", (long)migration_cost[distance] / 1000); - } - printk("\n"); - j1 = jiffies; - if (migration_debug) - printk("migration: %ld seconds\n", (j1-j0)/HZ); - - /* - * Move back to the original CPU. NUMA-Q gets confused - * if we migrate to another quad during bootup. - */ - if (raw_smp_processor_id() != orig_cpu) { - cpumask_t mask = cpumask_of_cpu(orig_cpu), - saved_mask = current->cpus_allowed; - - set_cpus_allowed(current, mask); - set_cpus_allowed(current, saved_mask); - } -} - -#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) -{ - int i; - cpumask_t span, nodemask; - DECLARE_BITMAP(used_nodes, MAX_NUMNODES); - - 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 - -/* - * At the moment, CONFIG_SCHED_SMT is never defined, but leave it in so we - * can switch it on easily if needed. - */ -#ifdef CONFIG_SCHED_SMT -static DEFINE_PER_CPU(struct sched_domain, cpu_domains); -static struct sched_group sched_group_cpus[NR_CPUS]; -static int cpu_to_cpu_group(int cpu) -{ - return cpu; -} -#endif - -static DEFINE_PER_CPU(struct sched_domain, phys_domains); -static struct sched_group sched_group_phys[NR_CPUS]; -static int cpu_to_phys_group(int cpu) -{ -#ifdef CONFIG_SCHED_SMT - return first_cpu(cpu_sibling_map[cpu]); -#else - return cpu; -#endif -} - -#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 struct sched_group *sched_group_allnodes_bycpu[NR_CPUS]; - -static int cpu_to_allnodes_group(int cpu) -{ - return cpu_to_node(cpu); -} -#endif - -/* - * Build sched domains for a given set of cpus and attach the sched domains - * to the individual cpus - */ -void build_sched_domains(const cpumask_t *cpu_map) -{ - int i; -#ifdef CONFIG_NUMA - struct sched_group **sched_group_nodes = NULL; - struct sched_group *sched_group_allnodes = NULL; - - /* - * Allocate the per-node list of sched groups - */ - sched_group_nodes = kmalloc(sizeof(struct sched_group*)*MAX_NUMNODES, - GFP_ATOMIC); - if (!sched_group_nodes) { - printk(KERN_WARNING "Can not alloc sched group node list\n"); - return; - } - sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; -#endif - - /* - * Set up domains for cpus specified by the cpu_map. - */ - for_each_cpu_mask(i, *cpu_map) { - int group; - 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)) { - if (!sched_group_allnodes) { - sched_group_allnodes - = kmalloc(sizeof(struct sched_group) - * MAX_NUMNODES, - GFP_KERNEL); - if (!sched_group_allnodes) { - printk(KERN_WARNING - "Can not alloc allnodes sched group\n"); - break; - } - sched_group_allnodes_bycpu[i] - = sched_group_allnodes; - } - sd = &per_cpu(allnodes_domains, i); - *sd = SD_ALLNODES_INIT; - sd->span = *cpu_map; - group = cpu_to_allnodes_group(i); - sd->groups = &sched_group_allnodes[group]; - p = sd; - } 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; - cpus_and(sd->span, sd->span, *cpu_map); -#endif - - p = sd; - sd = &per_cpu(phys_domains, i); - group = cpu_to_phys_group(i); - *sd = SD_CPU_INIT; - sd->span = nodemask; - sd->parent = p; - sd->groups = &sched_group_phys[group]; - -#ifdef CONFIG_SCHED_SMT - p = sd; - sd = &per_cpu(cpu_domains, i); - group = cpu_to_cpu_group(i); - *sd = SD_SIBLING_INIT; - sd->span = cpu_sibling_map[i]; - cpus_and(sd->span, sd->span, *cpu_map); - sd->parent = p; - sd->groups = &sched_group_cpus[group]; -#endif - } - -#ifdef CONFIG_SCHED_SMT - /* Set up CPU (sibling) groups */ - for_each_cpu_mask(i, *cpu_map) { - cpumask_t this_sibling_map = 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(sched_group_cpus, this_sibling_map, - &cpu_to_cpu_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(sched_group_phys, nodemask, - &cpu_to_phys_group); - } - -#ifdef CONFIG_NUMA - /* Set up node groups */ - if (sched_group_allnodes) - init_sched_build_groups(sched_group_allnodes, *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(sizeof(struct sched_group), GFP_KERNEL); - sched_group_nodes[i] = sg; - for_each_cpu_mask(j, nodemask) { - struct sched_domain *sd; - sd = &per_cpu(node_domains, j); - sd->groups = sg; - if (sd->groups == NULL) { - /* Turn off balancing if we have no groups */ - sd->flags = 0; - } - } - if (!sg) { - printk(KERN_WARNING - "Can not alloc domain group for node %d\n", i); - continue; - } - sg->cpu_power = 0; - sg->cpumask = nodemask; - 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(sizeof(struct sched_group), GFP_KERNEL); - if (!sg) { - printk(KERN_WARNING - "Can not alloc domain group for node %d\n", j); - break; - } - sg->cpu_power = 0; - sg->cpumask = tmp; - cpus_or(covered, covered, tmp); - prev->next = sg; - prev = sg; - } - prev->next = sched_group_nodes[i]; - } -#endif - - /* Calculate CPU power for physical packages and nodes */ - for_each_cpu_mask(i, *cpu_map) { - int power; - struct sched_domain *sd; -#ifdef CONFIG_SCHED_SMT - sd = &per_cpu(cpu_domains, i); - power = SCHED_LOAD_SCALE; - sd->groups->cpu_power = power; -#endif - - sd = &per_cpu(phys_domains, i); - power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE * - (cpus_weight(sd->groups->cpumask)-1) / 10; - sd->groups->cpu_power = power; - -#ifdef CONFIG_NUMA - sd = &per_cpu(allnodes_domains, i); - if (sd->groups) { - power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE * - (cpus_weight(sd->groups->cpumask)-1) / 10; - sd->groups->cpu_power = power; - } -#endif - } - -#ifdef CONFIG_NUMA - for (i = 0; i < MAX_NUMNODES; i++) { - struct sched_group *sg = sched_group_nodes[i]; - int j; - - if (sg == NULL) - continue; -next_sg: - for_each_cpu_mask(j, sg->cpumask) { - struct sched_domain *sd; - int power; - - sd = &per_cpu(phys_domains, j); - if (j != first_cpu(sd->groups->cpumask)) { - /* - * Only add "power" once for each - * physical package. - */ - continue; - } - power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE * - (cpus_weight(sd->groups->cpumask)-1) / 10; - - sg->cpu_power += power; - } - sg = sg->next; - if (sg != sched_group_nodes[i]) - goto next_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); -#else - sd = &per_cpu(phys_domains, i); -#endif - cpu_attach_domain(sd, i); - } - /* - * Tune cache-hot values: - */ - calibrate_migration_costs(cpu_map); -} -/* - * Set up scheduler domains and groups. Callers must hold the hotplug lock. - */ -static void arch_init_sched_domains(const cpumask_t *cpu_map) -{ - cpumask_t cpu_default_map; - - /* - * Setup mask for cpus without special case scheduling requirements. - * For now this just excludes isolated cpus, but could be used to - * exclude other special cases in the future. - */ - cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); - - build_sched_domains(&cpu_default_map); -} - -static void arch_destroy_sched_domains(const cpumask_t *cpu_map) -{ -#ifdef CONFIG_NUMA - int i; - int cpu; - - for_each_cpu_mask(cpu, *cpu_map) { - struct sched_group *sched_group_allnodes - = sched_group_allnodes_bycpu[cpu]; - struct sched_group **sched_group_nodes - = sched_group_nodes_bycpu[cpu]; - - if (sched_group_allnodes) { - kfree(sched_group_allnodes); - sched_group_allnodes_bycpu[cpu] = NULL; - } - - 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; - } -#endif -} - -/* - * 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; - - for_each_cpu_mask(i, *cpu_map) - cpu_attach_domain(NULL, i); - synchronize_sched(); - arch_destroy_sched_domains(cpu_map); -} - -/* - * Partition sched domains as specified by the cpumasks below. - * This attaches all cpus from the cpumasks to the NULL domain, - * waits for a RCU quiescent period, recalculates sched - * domain information and then attaches them back to the - * correct sched domains - * Call with hotplug lock held - */ -void partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) -{ - cpumask_t change_map; - - cpus_and(*partition1, *partition1, cpu_online_map); - cpus_and(*partition2, *partition2, cpu_online_map); - cpus_or(change_map, *partition1, *partition2); - - /* Detach sched domains from all of the affected cpus */ - detach_destroy_domains(&change_map); - if (!cpus_empty(*partition1)) - build_sched_domains(partition1); - if (!cpus_empty(*partition2)) - build_sched_domains(partition2); -} - -#ifdef CONFIG_HOTPLUG_CPU -/* - * 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_DOWN_PREPARE: - detach_destroy_domains(&cpu_online_map); - return NOTIFY_OK; - - case CPU_UP_CANCELED: - case CPU_DOWN_FAILED: - case CPU_ONLINE: - case CPU_DEAD: - /* - * 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; -} -#endif - -void __init sched_init_smp(void) -{ - lock_cpu_hotplug(); - arch_init_sched_domains(&cpu_online_map); - unlock_cpu_hotplug(); - /* XXX: Theoretical race here - CPU may be hotplugged now */ - hotcpu_notifier(update_sched_domains, 0); -} -#else -void __init sched_init_smp(void) -{ -} -#endif /* CONFIG_SMP */ - -int in_sched_functions(unsigned long addr) -{ - /* Linker adds these: start and end of __sched functions */ - extern char __sched_text_start[], __sched_text_end[]; - return in_lock_functions(addr) || - (addr >= (unsigned long)__sched_text_start - && addr < (unsigned long)__sched_text_end); -} - -void __init sched_init(void) -{ - runqueue_t *rq; - int i, j, k; - - for (i = 0; i < NR_CPUS; i++) { - prio_array_t *array; - - rq = cpu_rq(i); - spin_lock_init(&rq->lock); - rq->nr_running = 0; - rq->active = rq->arrays; - rq->expired = rq->arrays + 1; - rq->best_expired_prio = MAX_PRIO; - -#ifdef CONFIG_SMP - rq->sd = NULL; - for (j = 1; j < 3; j++) - rq->cpu_load[j] = 0; - rq->active_balance = 0; - rq->push_cpu = 0; - rq->migration_thread = NULL; - INIT_LIST_HEAD(&rq->migration_queue); -#endif - atomic_set(&rq->nr_iowait, 0); - - for (j = 0; j < 2; j++) { - array = rq->arrays + j; - for (k = 0; k < MAX_PRIO; k++) { - INIT_LIST_HEAD(array->queue + k); - __clear_bit(k, array->bitmap); - } - // delimiter for bitsearch - __set_bit(MAX_PRIO, array->bitmap); - } - } - - /* - * The boot idle thread does lazy MMU switching as well: - */ - atomic_inc(&init_mm.mm_count); - enter_lazy_tlb(&init_mm, current); - - /* - * Make us the idle thread. Technically, schedule() should not be - * called from this thread, however somewhere below it might be, - * but because we are the idle thread, we just pick up running again - * when this runqueue becomes "idle". - */ - init_idle(current, smp_processor_id()); -} - -#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP -void __might_sleep(char *file, int line) -{ -#if defined(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 "Debug: sleeping function called from invalid" - " context at %s:%d\n", file, line); - printk("in_atomic():%d, irqs_disabled():%d\n", - in_atomic(), irqs_disabled()); - dump_stack(); - } -#endif -} -EXPORT_SYMBOL(__might_sleep); -#endif - -#ifdef CONFIG_MAGIC_SYSRQ -void normalize_rt_tasks(void) -{ - struct task_struct *p; - prio_array_t *array; - unsigned long flags; - runqueue_t *rq; - - read_lock_irq(&tasklist_lock); - for_each_process (p) { - if (!rt_task(p)) - continue; - - rq = task_rq_lock(p, &flags); - - array = p->array; - if (array) - deactivate_task(p, task_rq(p)); - __setscheduler(p, SCHED_NORMAL, 0); - if (array) { - __activate_task(p, task_rq(p)); - resched_task(rq->curr); - } - - task_rq_unlock(rq, &flags); - } - read_unlock_irq(&tasklist_lock); -} - -#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! - */ -task_t *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, task_t *p) -{ - cpu_curr(cpu) = p; -} - -#endif |