* by Davide Libenzi, preemptible kernel bits by Robert Love.
* 2003-09-03 Interactivity tuning by Con Kolivas.
* 2004-04-02 Scheduler domains code by Nick Piggin
+ * 2007-04-15 Work begun on replacing all interactivity tuning with a
+ * fair scheduling design by Con Kolivas.
+ * 2007-05-05 Load balancing (smp-nice) and other improvements
+ * by Peter Williams
+ * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
+ * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
*/
#include <linux/mm.h>
#include <linux/module.h>
#include <linux/nmi.h>
#include <linux/init.h>
-#include <asm/uaccess.h>
+#include <linux/uaccess.h>
#include <linux/highmem.h>
#include <linux/smp_lock.h>
#include <asm/mmu_context.h>
#include <linux/tsacct_kern.h>
#include <linux/kprobes.h>
#include <linux/delayacct.h>
-#include <asm/tlb.h>
+#include <linux/reciprocal_div.h>
+#include <linux/unistd.h>
-#include <asm/unistd.h>
+#include <asm/tlb.h>
/*
* Scheduler clock - returns current time in nanosec units.
#define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ))
#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ))
+#define NICE_0_LOAD SCHED_LOAD_SCALE
+#define NICE_0_SHIFT SCHED_LOAD_SHIFT
+
/*
* These are the 'tuning knobs' of the scheduler:
*
*/
#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))
+#ifdef CONFIG_SMP
/*
- * 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.
+ * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
+ * Since cpu_power is a 'constant', we can use a reciprocal divide.
*/
+static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
+{
+ return reciprocal_divide(load, sg->reciprocal_cpu_power);
+}
-#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)))
+/*
+ * Each time a sched group cpu_power is changed,
+ * we must compute its reciprocal value
+ */
+static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
+{
+ sg->__cpu_power += val;
+ sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
+}
#endif
-#define SCALE(v1,v1_max,v2_max) \
- (v1) * (v2_max) / (v1_max)
-
-#define DELTA(p) \
- (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \
- 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)
-
#define SCALE_PRIO(x, prio) \
max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE)
+/*
+ * static_prio_timeslice() scales user-nice values [ -20 ... 0 ... 19 ]
+ * to time slice values: [800ms ... 100ms ... 5ms]
+ */
static unsigned int static_prio_timeslice(int static_prio)
{
+ if (static_prio == NICE_TO_PRIO(19))
+ return 1;
+
if (static_prio < NICE_TO_PRIO(0))
return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio);
else
return SCALE_PRIO(DEF_TIMESLICE, static_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.
- */
+static inline int rt_policy(int policy)
+{
+ if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR))
+ return 1;
+ return 0;
+}
-static inline unsigned int task_timeslice(struct task_struct *p)
+static inline int task_has_rt_policy(struct task_struct *p)
{
- return static_prio_timeslice(p->static_prio);
+ return rt_policy(p->policy);
}
/*
- * These are the runqueue data structures:
+ * This is the priority-queue data structure of the RT scheduling class:
*/
+struct rt_prio_array {
+ DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
+ struct list_head queue[MAX_RT_PRIO];
+};
+
+struct load_stat {
+ struct load_weight load;
+ u64 load_update_start, load_update_last;
+ unsigned long delta_fair, delta_exec, delta_stat;
+};
+
+/* CFS-related fields in a runqueue */
+struct cfs_rq {
+ struct load_weight load;
+ unsigned long nr_running;
+
+ s64 fair_clock;
+ u64 exec_clock;
+ s64 wait_runtime;
+ u64 sleeper_bonus;
+ unsigned long wait_runtime_overruns, wait_runtime_underruns;
+
+ struct rb_root tasks_timeline;
+ struct rb_node *rb_leftmost;
+ struct rb_node *rb_load_balance_curr;
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ /* 'curr' points to currently running entity on this cfs_rq.
+ * It is set to NULL otherwise (i.e when none are currently running).
+ */
+ struct sched_entity *curr;
+ struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
+
+ /* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
+ * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
+ * (like users, containers etc.)
+ *
+ * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
+ * list is used during load balance.
+ */
+ struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */
+#endif
+};
-struct prio_array {
- unsigned int nr_active;
- DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */
- struct list_head queue[MAX_PRIO];
+/* Real-Time classes' related field in a runqueue: */
+struct rt_rq {
+ struct rt_prio_array active;
+ int rt_load_balance_idx;
+ struct list_head *rt_load_balance_head, *rt_load_balance_curr;
};
/*
* acquire operations must be ordered by ascending &runqueue.
*/
struct rq {
- spinlock_t lock;
+ spinlock_t lock; /* runqueue 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;
- unsigned long raw_weighted_load;
-#ifdef CONFIG_SMP
- unsigned long cpu_load[3];
+ #define CPU_LOAD_IDX_MAX 5
+ unsigned long cpu_load[CPU_LOAD_IDX_MAX];
+ unsigned char idle_at_tick;
+#ifdef CONFIG_NO_HZ
+ unsigned char in_nohz_recently;
+#endif
+ struct load_stat ls; /* capture load from *all* tasks on this cpu */
+ unsigned long nr_load_updates;
+ u64 nr_switches;
+
+ struct cfs_rq cfs;
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ struct list_head leaf_cfs_rq_list; /* list of leaf cfs_rq on this cpu */
#endif
- unsigned long long nr_switches;
+ struct rt_rq rt;
/*
* This is part of a global counter where only the total sum
*/
unsigned long nr_uninterruptible;
- unsigned long expired_timestamp;
- /* Cached timestamp set by update_cpu_clock() */
- unsigned long long most_recent_timestamp;
struct task_struct *curr, *idle;
unsigned long next_balance;
struct mm_struct *prev_mm;
- struct prio_array *active, *expired, arrays[2];
- int best_expired_prio;
+
+ u64 clock, prev_clock_raw;
+ s64 clock_max_delta;
+
+ unsigned int clock_warps, clock_overflows;
+ unsigned int clock_unstable_events;
+
+ struct sched_class *load_balance_class;
+
atomic_t nr_iowait;
#ifdef CONFIG_SMP
struct lock_class_key rq_lock_key;
};
-static DEFINE_PER_CPU(struct rq, runqueues);
+static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp;
+static DEFINE_MUTEX(sched_hotcpu_mutex);
+
+static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
+{
+ rq->curr->sched_class->check_preempt_curr(rq, p);
+}
static inline int cpu_of(struct rq *rq)
{
}
/*
+ * Per-runqueue clock, as finegrained as the platform can give us:
+ */
+static unsigned long long __rq_clock(struct rq *rq)
+{
+ u64 prev_raw = rq->prev_clock_raw;
+ u64 now = sched_clock();
+ s64 delta = now - prev_raw;
+ u64 clock = rq->clock;
+
+ /*
+ * Protect against sched_clock() occasionally going backwards:
+ */
+ if (unlikely(delta < 0)) {
+ clock++;
+ rq->clock_warps++;
+ } else {
+ /*
+ * Catch too large forward jumps too:
+ */
+ if (unlikely(delta > 2*TICK_NSEC)) {
+ clock++;
+ rq->clock_overflows++;
+ } else {
+ if (unlikely(delta > rq->clock_max_delta))
+ rq->clock_max_delta = delta;
+ clock += delta;
+ }
+ }
+
+ rq->prev_clock_raw = now;
+ rq->clock = clock;
+
+ return clock;
+}
+
+static inline unsigned long long rq_clock(struct rq *rq)
+{
+ int this_cpu = smp_processor_id();
+
+ if (this_cpu == cpu_of(rq))
+ return __rq_clock(rq);
+
+ return rq->clock;
+}
+
+/*
* The domain tree (rq->sd) is protected by RCU's quiescent state transition.
* See detach_destroy_domains: synchronize_sched for details.
*
#define task_rq(p) cpu_rq(task_cpu(p))
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
+#ifdef CONFIG_FAIR_GROUP_SCHED
+/* Change a task's ->cfs_rq if it moves across CPUs */
+static inline void set_task_cfs_rq(struct task_struct *p)
+{
+ p->se.cfs_rq = &task_rq(p)->cfs;
+}
+#else
+static inline void set_task_cfs_rq(struct task_struct *p)
+{
+}
+#endif
+
#ifndef prepare_arch_switch
# define prepare_arch_switch(next) do { } while (0)
#endif
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 14
-
-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) {
- struct rq *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;
-}
-
-const struct file_operations proc_schedstat_operations = {
- .open = schedstat_open,
- .read = seq_read,
- .llseek = seq_lseek,
- .release = single_release,
-};
-
-/*
- * Expects runqueue lock to be held for atomicity of update
- */
-static inline void
-rq_sched_info_arrive(struct rq *rq, unsigned long delta_jiffies)
-{
- if (rq) {
- rq->rq_sched_info.run_delay += delta_jiffies;
- rq->rq_sched_info.pcnt++;
- }
-}
-
-/*
- * Expects runqueue lock to be held for atomicity of update
- */
-static inline void
-rq_sched_info_depart(struct rq *rq, unsigned long delta_jiffies)
-{
- if (rq)
- rq->rq_sched_info.cpu_time += delta_jiffies;
-}
-# 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 */
-static inline void
-rq_sched_info_arrive(struct rq *rq, unsigned long delta_jiffies)
-{}
-static inline void
-rq_sched_info_depart(struct rq *rq, unsigned long delta_jiffies)
-{}
-# define schedstat_inc(rq, field) do { } while (0)
-# define schedstat_add(rq, field, amt) do { } while (0)
-#endif
-
/*
* this_rq_lock - lock this runqueue and disable interrupts.
*/
return rq;
}
-#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
/*
- * 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.
+ * CPU frequency is/was unstable - start new by setting prev_clock_raw:
*/
-static inline void sched_info_dequeued(struct task_struct *t)
+void sched_clock_unstable_event(void)
{
- t->sched_info.last_queued = 0;
+ unsigned long flags;
+ struct rq *rq;
+
+ rq = task_rq_lock(current, &flags);
+ rq->prev_clock_raw = sched_clock();
+ rq->clock_unstable_events++;
+ task_rq_unlock(rq, &flags);
}
/*
- * 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.
+ * 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.
*/
-static void sched_info_arrive(struct task_struct *t)
+#ifdef CONFIG_SMP
+
+#ifndef tsk_is_polling
+#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
+#endif
+
+static void resched_task(struct task_struct *p)
{
- unsigned long now = jiffies, delta_jiffies = 0;
+ int cpu;
+
+ assert_spin_locked(&task_rq(p)->lock);
+
+ if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+ return;
- if (t->sched_info.last_queued)
- delta_jiffies = now - t->sched_info.last_queued;
- sched_info_dequeued(t);
- t->sched_info.run_delay += delta_jiffies;
- t->sched_info.last_arrival = now;
- t->sched_info.pcnt++;
+ set_tsk_thread_flag(p, TIF_NEED_RESCHED);
+
+ cpu = task_cpu(p);
+ if (cpu == smp_processor_id())
+ return;
- rq_sched_info_arrive(task_rq(t), delta_jiffies);
+ /* NEED_RESCHED must be visible before we test polling */
+ smp_mb();
+ if (!tsk_is_polling(p))
+ smp_send_reschedule(cpu);
}
-/*
- * 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(struct task_struct *t)
+static void resched_cpu(int cpu)
{
- if (unlikely(sched_info_on()))
- if (!t->sched_info.last_queued)
- t->sched_info.last_queued = jiffies;
+ struct rq *rq = cpu_rq(cpu);
+ unsigned long flags;
+
+ if (!spin_trylock_irqsave(&rq->lock, flags))
+ return;
+ resched_task(cpu_curr(cpu));
+ spin_unlock_irqrestore(&rq->lock, flags);
}
+#else
+static inline void resched_task(struct task_struct *p)
+{
+ assert_spin_locked(&task_rq(p)->lock);
+ set_tsk_need_resched(p);
+}
+#endif
-/*
- * 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(struct task_struct *t)
+static u64 div64_likely32(u64 divident, unsigned long divisor)
{
- unsigned long delta_jiffies = jiffies - t->sched_info.last_arrival;
+#if BITS_PER_LONG == 32
+ if (likely(divident <= 0xffffffffULL))
+ return (u32)divident / divisor;
+ do_div(divident, divisor);
- t->sched_info.cpu_time += delta_jiffies;
- rq_sched_info_depart(task_rq(t), delta_jiffies);
+ return divident;
+#else
+ return divident / divisor;
+#endif
}
-/*
- * 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(struct task_struct *prev, struct task_struct *next)
+#if BITS_PER_LONG == 32
+# define WMULT_CONST (~0UL)
+#else
+# define WMULT_CONST (1UL << 32)
+#endif
+
+#define WMULT_SHIFT 32
+
+static inline unsigned long
+calc_delta_mine(unsigned long delta_exec, unsigned long weight,
+ struct load_weight *lw)
{
- struct rq *rq = task_rq(prev);
+ u64 tmp;
+
+ if (unlikely(!lw->inv_weight))
+ lw->inv_weight = WMULT_CONST / lw->weight;
+ tmp = (u64)delta_exec * weight;
/*
- * prev now departs the cpu. It's not interesting to record
- * stats about how efficient we were at scheduling the idle
- * process, however.
+ * Check whether we'd overflow the 64-bit multiplication:
*/
- if (prev != rq->idle)
- sched_info_depart(prev);
+ if (unlikely(tmp > WMULT_CONST)) {
+ tmp = ((tmp >> WMULT_SHIFT/2) * lw->inv_weight)
+ >> (WMULT_SHIFT/2);
+ } else {
+ tmp = (tmp * lw->inv_weight) >> WMULT_SHIFT;
+ }
- if (next != rq->idle)
- sched_info_arrive(next);
+ return (unsigned long)min(tmp, (u64)sysctl_sched_runtime_limit);
}
-static inline void
-sched_info_switch(struct task_struct *prev, struct task_struct *next)
-{
- if (unlikely(sched_info_on()))
- __sched_info_switch(prev, next);
-}
-#else
-#define sched_info_queued(t) do { } while (0)
-#define sched_info_switch(t, next) do { } while (0)
-#endif /* CONFIG_SCHEDSTATS || CONFIG_TASK_DELAY_ACCT */
-/*
- * Adding/removing a task to/from a priority array:
- */
-static void dequeue_task(struct task_struct *p, struct prio_array *array)
+static inline unsigned long
+calc_delta_fair(unsigned long delta_exec, struct load_weight *lw)
{
- array->nr_active--;
- list_del(&p->run_list);
- if (list_empty(array->queue + p->prio))
- __clear_bit(p->prio, array->bitmap);
+ return calc_delta_mine(delta_exec, NICE_0_LOAD, lw);
}
-static void enqueue_task(struct task_struct *p, struct prio_array *array)
+static void update_load_add(struct load_weight *lw, unsigned long inc)
{
- 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;
+ lw->weight += inc;
+ lw->inv_weight = 0;
}
-/*
- * 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, struct prio_array *array)
+static void update_load_sub(struct load_weight *lw, unsigned long dec)
{
- list_move_tail(&p->run_list, array->queue + p->prio);
+ lw->weight -= dec;
+ lw->inv_weight = 0;
}
-static inline void
-enqueue_task_head(struct task_struct *p, struct prio_array *array)
+static void __update_curr_load(struct rq *rq, struct load_stat *ls)
{
- list_add(&p->run_list, array->queue + p->prio);
- __set_bit(p->prio, array->bitmap);
- array->nr_active++;
- p->array = array;
+ if (rq->curr != rq->idle && ls->load.weight) {
+ ls->delta_exec += ls->delta_stat;
+ ls->delta_fair += calc_delta_fair(ls->delta_stat, &ls->load);
+ ls->delta_stat = 0;
+ }
}
/*
- * __normal_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.
+ * Update delta_exec, delta_fair fields for rq.
*
- * We use 25% of the full 0...39 priority range so that:
+ * delta_fair clock advances at a rate inversely proportional to
+ * total load (rq->ls.load.weight) on the runqueue, while
+ * delta_exec advances at the same rate as wall-clock (provided
+ * cpu is not idle).
*
- * 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.
+ * delta_exec / delta_fair is a measure of the (smoothened) load on this
+ * runqueue over any given interval. This (smoothened) load is used
+ * during load balance.
*
- * Both properties are important to certain workloads.
+ * This function is called /before/ updating rq->ls.load
+ * and when switching tasks.
*/
-
-static inline int __normal_prio(struct task_struct *p)
+static void update_curr_load(struct rq *rq, u64 now)
{
- int bonus, prio;
-
- bonus = CURRENT_BONUS(p) - MAX_BONUS / 2;
+ struct load_stat *ls = &rq->ls;
+ u64 start;
- 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;
+ start = ls->load_update_start;
+ ls->load_update_start = now;
+ ls->delta_stat += now - start;
+ /*
+ * Stagger updates to ls->delta_fair. Very frequent updates
+ * can be expensive.
+ */
+ if (ls->delta_stat >= sysctl_sched_stat_granularity)
+ __update_curr_load(rq, ls);
}
/*
* this code will need modification
*/
#define TIME_SLICE_NICE_ZERO DEF_TIMESLICE
-#define LOAD_WEIGHT(lp) \
+#define load_weight(lp) \
(((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO)
#define PRIO_TO_LOAD_WEIGHT(prio) \
- LOAD_WEIGHT(static_prio_timeslice(prio))
+ load_weight(static_prio_timeslice(prio))
#define RTPRIO_TO_LOAD_WEIGHT(rp) \
- (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + LOAD_WEIGHT(rp))
+ (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + load_weight(rp))
-static void set_load_weight(struct task_struct *p)
-{
- if (has_rt_policy(p)) {
-#ifdef CONFIG_SMP
- if (p == task_rq(p)->migration_thread)
- /*
- * The migration thread does the actual balancing.
- * Giving its load any weight will skew balancing
- * adversely.
- */
- p->load_weight = 0;
- else
-#endif
- p->load_weight = RTPRIO_TO_LOAD_WEIGHT(p->rt_priority);
- } else
- p->load_weight = PRIO_TO_LOAD_WEIGHT(p->static_prio);
-}
+#define WEIGHT_IDLEPRIO 2
+#define WMULT_IDLEPRIO (1 << 31)
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+static const int prio_to_weight[40] = {
+/* -20 */ 88818, 71054, 56843, 45475, 36380, 29104, 23283, 18626, 14901, 11921,
+/* -10 */ 9537, 7629, 6103, 4883, 3906, 3125, 2500, 2000, 1600, 1280,
+/* 0 */ NICE_0_LOAD /* 1024 */,
+/* 1 */ 819, 655, 524, 419, 336, 268, 215, 172, 137,
+/* 10 */ 110, 87, 70, 56, 45, 36, 29, 23, 18, 15,
+};
+
+/*
+ * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+static const u32 prio_to_wmult[40] = {
+/* -20 */ 48356, 60446, 75558, 94446, 118058,
+/* -15 */ 147573, 184467, 230589, 288233, 360285,
+/* -10 */ 450347, 562979, 703746, 879575, 1099582,
+/* -5 */ 1374389, 1717986, 2147483, 2684354, 3355443,
+/* 0 */ 4194304, 5244160, 6557201, 8196502, 10250518,
+/* 5 */ 12782640, 16025997, 19976592, 24970740, 31350126,
+/* 10 */ 39045157, 49367440, 61356675, 76695844, 95443717,
+/* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
static inline void
-inc_raw_weighted_load(struct rq *rq, const struct task_struct *p)
+inc_load(struct rq *rq, const struct task_struct *p, u64 now)
{
- rq->raw_weighted_load += p->load_weight;
+ update_curr_load(rq, now);
+ update_load_add(&rq->ls.load, p->se.load.weight);
}
static inline void
-dec_raw_weighted_load(struct rq *rq, const struct task_struct *p)
+dec_load(struct rq *rq, const struct task_struct *p, u64 now)
{
- rq->raw_weighted_load -= p->load_weight;
+ update_curr_load(rq, now);
+ update_load_sub(&rq->ls.load, p->se.load.weight);
}
-static inline void inc_nr_running(struct task_struct *p, struct rq *rq)
+static inline void inc_nr_running(struct task_struct *p, struct rq *rq, u64 now)
{
rq->nr_running++;
- inc_raw_weighted_load(rq, p);
+ inc_load(rq, p, now);
}
-static inline void dec_nr_running(struct task_struct *p, struct rq *rq)
+static inline void dec_nr_running(struct task_struct *p, struct rq *rq, u64 now)
{
rq->nr_running--;
- dec_raw_weighted_load(rq, p);
+ dec_load(rq, p, now);
+}
+
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
+
+/*
+ * runqueue iterator, to support SMP load-balancing between different
+ * scheduling classes, without having to expose their internal data
+ * structures to the load-balancing proper:
+ */
+struct rq_iterator {
+ void *arg;
+ struct task_struct *(*start)(void *);
+ struct task_struct *(*next)(void *);
+};
+
+static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+ unsigned long max_nr_move, unsigned long max_load_move,
+ struct sched_domain *sd, enum cpu_idle_type idle,
+ int *all_pinned, unsigned long *load_moved,
+ int this_best_prio, int best_prio, int best_prio_seen,
+ struct rq_iterator *iterator);
+
+#include "sched_stats.h"
+#include "sched_rt.c"
+#include "sched_fair.c"
+#include "sched_idletask.c"
+#ifdef CONFIG_SCHED_DEBUG
+# include "sched_debug.c"
+#endif
+
+#define sched_class_highest (&rt_sched_class)
+
+static void set_load_weight(struct task_struct *p)
+{
+ task_rq(p)->cfs.wait_runtime -= p->se.wait_runtime;
+ p->se.wait_runtime = 0;
+
+ if (task_has_rt_policy(p)) {
+ p->se.load.weight = prio_to_weight[0] * 2;
+ p->se.load.inv_weight = prio_to_wmult[0] >> 1;
+ return;
+ }
+
+ /*
+ * SCHED_IDLE tasks get minimal weight:
+ */
+ if (p->policy == SCHED_IDLE) {
+ p->se.load.weight = WEIGHT_IDLEPRIO;
+ p->se.load.inv_weight = WMULT_IDLEPRIO;
+ return;
+ }
+
+ p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
+ p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
+}
+
+static void
+enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, u64 now)
+{
+ sched_info_queued(p);
+ p->sched_class->enqueue_task(rq, p, wakeup, now);
+ p->se.on_rq = 1;
+}
+
+static void
+dequeue_task(struct rq *rq, struct task_struct *p, int sleep, u64 now)
+{
+ p->sched_class->dequeue_task(rq, p, sleep, now);
+ p->se.on_rq = 0;
+}
+
+/*
+ * __normal_prio - return the priority that is based on the static prio
+ */
+static inline int __normal_prio(struct task_struct *p)
+{
+ return p->static_prio;
}
/*
{
int prio;
- if (has_rt_policy(p))
+ if (task_has_rt_policy(p))
prio = MAX_RT_PRIO-1 - p->rt_priority;
else
prio = __normal_prio(p);
}
/*
- * __activate_task - move a task to the runqueue.
- */
-static void __activate_task(struct task_struct *p, struct rq *rq)
-{
- struct prio_array *target = rq->active;
-
- if (batch_task(p))
- target = rq->expired;
- enqueue_task(p, target);
- inc_nr_running(p, rq);
-}
-
-/*
- * __activate_idle_task - move idle task to the _front_ of runqueue.
- */
-static inline void __activate_idle_task(struct task_struct *p, struct rq *rq)
-{
- enqueue_task_head(p, rq->active);
- inc_nr_running(p, rq);
-}
-
-/*
- * Recalculate p->normal_prio and p->prio after having slept,
- * updating the sleep-average too:
+ * activate_task - move a task to the runqueue.
*/
-static int recalc_task_prio(struct task_struct *p, unsigned long long now)
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
{
- /* Caller must always ensure 'now >= p->timestamp' */
- unsigned long sleep_time = now - p->timestamp;
-
- if (batch_task(p))
- sleep_time = 0;
-
- if (likely(sleep_time > 0)) {
- /*
- * This ceiling is set to the lowest priority that would allow
- * a task to be reinserted into the active array on timeslice
- * completion.
- */
- unsigned long ceiling = INTERACTIVE_SLEEP(p);
-
- if (p->mm && sleep_time > ceiling && p->sleep_avg < ceiling) {
- /*
- * Prevents user tasks from achieving best priority
- * with one single large enough sleep.
- */
- p->sleep_avg = ceiling;
- /*
- * Using INTERACTIVE_SLEEP() as a ceiling places a
- * nice(0) task 1ms sleep away from promotion, and
- * gives it 700ms to round-robin with no chance of
- * being demoted. This is more than generous, so
- * mark this sleep as non-interactive to prevent the
- * on-runqueue bonus logic from intervening should
- * this task not receive cpu immediately.
- */
- p->sleep_type = SLEEP_NONINTERACTIVE;
- } else {
- /*
- * Tasks waking from uninterruptible sleep are
- * limited in their sleep_avg rise as they
- * are likely to be waiting on I/O
- */
- if (p->sleep_type == SLEEP_NONINTERACTIVE && p->mm) {
- if (p->sleep_avg >= ceiling)
- sleep_time = 0;
- else if (p->sleep_avg + sleep_time >=
- ceiling) {
- p->sleep_avg = ceiling;
- sleep_time = 0;
- }
- }
+ u64 now = rq_clock(rq);
- /*
- * 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;
- }
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ rq->nr_uninterruptible--;
- return effective_prio(p);
+ enqueue_task(rq, p, wakeup, now);
+ inc_nr_running(p, rq, now);
}
/*
- * activate_task - move a task to the runqueue and do priority recalculation
- *
- * Update all the scheduling statistics stuff. (sleep average
- * calculation, priority modifiers, etc.)
+ * activate_idle_task - move idle task to the _front_ of runqueue.
*/
-static void activate_task(struct task_struct *p, struct rq *rq, int local)
+static inline void activate_idle_task(struct task_struct *p, struct rq *rq)
{
- unsigned long long now;
-
- if (rt_task(p))
- goto out;
-
- now = sched_clock();
-#ifdef CONFIG_SMP
- if (!local) {
- /* Compensate for drifting sched_clock */
- struct rq *this_rq = this_rq();
- now = (now - this_rq->most_recent_timestamp)
- + rq->most_recent_timestamp;
- }
-#endif
+ u64 now = rq_clock(rq);
- /*
- * Sleep time is in units of nanosecs, so shift by 20 to get a
- * milliseconds-range estimation of the amount of time that the task
- * spent sleeping:
- */
- if (unlikely(prof_on == SLEEP_PROFILING)) {
- if (p->state == TASK_UNINTERRUPTIBLE)
- profile_hits(SLEEP_PROFILING, (void *)get_wchan(p),
- (now - p->timestamp) >> 20);
- }
-
- p->prio = recalc_task_prio(p, now);
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ rq->nr_uninterruptible--;
- /*
- * This checks to make sure it's not an uninterruptible task
- * that is now waking up.
- */
- if (p->sleep_type == SLEEP_NORMAL) {
- /*
- * 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->sleep_type = SLEEP_INTERRUPTED;
- else {
- /*
- * Normal first-time wakeups get a credit too for
- * on-runqueue time, but it will be weighted down:
- */
- p->sleep_type = SLEEP_INTERACTIVE;
- }
- }
- p->timestamp = now;
-out:
- __activate_task(p, rq);
+ enqueue_task(rq, p, 0, now);
+ inc_nr_running(p, rq, now);
}
/*
* deactivate_task - remove a task from the runqueue.
*/
-static void deactivate_task(struct task_struct *p, struct rq *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
-
-#ifndef tsk_is_polling
-#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
-#endif
-
-static void resched_task(struct task_struct *p)
+static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
{
- int cpu;
-
- assert_spin_locked(&task_rq(p)->lock);
+ u64 now = rq_clock(rq);
- 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;
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ rq->nr_uninterruptible++;
- /* NEED_RESCHED must be visible before we test polling */
- smp_mb();
- if (!tsk_is_polling(p))
- smp_send_reschedule(cpu);
-}
-#else
-static inline void resched_task(struct task_struct *p)
-{
- assert_spin_locked(&task_rq(p)->lock);
- set_tsk_need_resched(p);
+ dequeue_task(rq, p, sleep, now);
+ dec_nr_running(p, rq, now);
}
-#endif
/**
* task_curr - is this task currently executing on a CPU?
/* Used instead of source_load when we know the type == 0 */
unsigned long weighted_cpuload(const int cpu)
{
- return cpu_rq(cpu)->raw_weighted_load;
+ return cpu_rq(cpu)->ls.load.weight;
+}
+
+static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
+{
+#ifdef CONFIG_SMP
+ task_thread_info(p)->cpu = cpu;
+ set_task_cfs_rq(p);
+#endif
}
#ifdef CONFIG_SMP
+
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
+{
+ int old_cpu = task_cpu(p);
+ struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
+ u64 clock_offset, fair_clock_offset;
+
+ clock_offset = old_rq->clock - new_rq->clock;
+ fair_clock_offset = old_rq->cfs.fair_clock -
+ new_rq->cfs.fair_clock;
+ if (p->se.wait_start)
+ p->se.wait_start -= clock_offset;
+ if (p->se.wait_start_fair)
+ p->se.wait_start_fair -= fair_clock_offset;
+ if (p->se.sleep_start)
+ p->se.sleep_start -= clock_offset;
+ if (p->se.block_start)
+ p->se.block_start -= clock_offset;
+ if (p->se.sleep_start_fair)
+ p->se.sleep_start_fair -= fair_clock_offset;
+
+ __set_task_cpu(p, new_cpu);
+}
+
struct migration_req {
struct list_head list;
* 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)) {
+ if (!p->se.on_rq && !task_running(rq, p)) {
set_task_cpu(p, dest_cpu);
return 0;
}
void wait_task_inactive(struct task_struct *p)
{
unsigned long flags;
+ int running, on_rq;
struct rq *rq;
- int preempted;
repeat:
+ /*
+ * We do the initial early heuristics without holding
+ * any task-queue locks at all. We'll only try to get
+ * the runqueue lock when things look like they will
+ * work out!
+ */
+ rq = task_rq(p);
+
+ /*
+ * If the task is actively running on another CPU
+ * still, just relax and busy-wait without holding
+ * any locks.
+ *
+ * NOTE! Since we don't hold any locks, it's not
+ * even sure that "rq" stays as the right runqueue!
+ * But we don't care, since "task_running()" will
+ * return false if the runqueue has changed and p
+ * is actually now running somewhere else!
+ */
+ while (task_running(rq, p))
+ cpu_relax();
+
+ /*
+ * Ok, time to look more closely! We need the rq
+ * lock now, to be *sure*. If we're wrong, we'll
+ * just go back and repeat.
+ */
rq = task_rq_lock(p, &flags);
- /* 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);
+ running = task_running(rq, p);
+ on_rq = p->se.on_rq;
+ task_rq_unlock(rq, &flags);
+
+ /*
+ * Was it really running after all now that we
+ * checked with the proper locks actually held?
+ *
+ * Oops. Go back and try again..
+ */
+ if (unlikely(running)) {
cpu_relax();
- if (preempted)
- yield();
goto repeat;
}
- task_rq_unlock(rq, &flags);
+
+ /*
+ * It's not enough that it's not actively running,
+ * it must be off the runqueue _entirely_, and not
+ * preempted!
+ *
+ * So if it wa still runnable (but just not actively
+ * running right now), it's preempted, and we should
+ * yield - it could be a while.
+ */
+ if (unlikely(on_rq)) {
+ yield();
+ goto repeat;
+ }
+
+ /*
+ * Ahh, all good. It wasn't running, and it wasn't
+ * runnable, which means that it will never become
+ * running in the future either. We're all done!
+ */
}
/***
static inline unsigned long source_load(int cpu, int type)
{
struct rq *rq = cpu_rq(cpu);
+ unsigned long total = weighted_cpuload(cpu);
if (type == 0)
- return rq->raw_weighted_load;
+ return total;
- return min(rq->cpu_load[type-1], rq->raw_weighted_load);
+ return min(rq->cpu_load[type-1], total);
}
/*
static inline unsigned long target_load(int cpu, int type)
{
struct rq *rq = cpu_rq(cpu);
+ unsigned long total = weighted_cpuload(cpu);
if (type == 0)
- return rq->raw_weighted_load;
+ return total;
- return max(rq->cpu_load[type-1], rq->raw_weighted_load);
+ return max(rq->cpu_load[type-1], total);
}
/*
static inline unsigned long cpu_avg_load_per_task(int cpu)
{
struct rq *rq = cpu_rq(cpu);
+ unsigned long total = weighted_cpuload(cpu);
unsigned long n = rq->nr_running;
- return n ? rq->raw_weighted_load / n : SCHED_LOAD_SCALE;
+ return n ? total / n : SCHED_LOAD_SCALE;
}
/*
}
/* Adjust by relative CPU power of the group */
- avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
+ avg_load = sg_div_cpu_power(group,
+ avg_load * SCHED_LOAD_SCALE);
if (local_group) {
this_load = avg_load;
struct sched_domain *tmp, *sd = NULL;
for_each_domain(cpu, tmp) {
- /*
- * If power savings logic is enabled for a domain, stop there.
- */
+ /*
+ * If power savings logic is enabled for a domain, stop there.
+ */
if (tmp->flags & SD_POWERSAVINGS_BALANCE)
break;
if (tmp->flags & flag)
struct sched_domain *sd;
int i;
- if (idle_cpu(cpu))
+ /*
+ * If it is idle, then it is the best cpu to run this task.
+ *
+ * This cpu is also the best, if it has more than one task already.
+ * Siblings must be also busy(in most cases) as they didn't already
+ * pickup the extra load from this cpu and hence we need not check
+ * sibling runqueue info. This will avoid the checks and cache miss
+ * penalities associated with that.
+ */
+ if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1)
return cpu;
for_each_domain(cpu, sd) {
if (idle_cpu(i))
return i;
}
- }
- else
+ } else {
break;
+ }
}
return cpu;
}
if (!(old_state & state))
goto out;
- if (p->array)
+ if (p->se.on_rq)
goto out_running;
cpu = task_cpu(p);
* of the current CPU:
*/
if (sync)
- tl -= current->load_weight;
+ tl -= current->se.load.weight;
if ((tl <= load &&
tl + target_load(cpu, idx) <= tl_per_task) ||
- 100*(tl + p->load_weight) <= imbalance*load) {
+ 100*(tl + p->se.load.weight) <= imbalance*load) {
/*
* This domain has SD_WAKE_AFFINE and
* p is cache cold in this domain, and
old_state = p->state;
if (!(old_state & state))
goto out;
- if (p->array)
+ if (p->se.on_rq)
goto out_running;
this_cpu = smp_processor_id();
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->sleep_type = SLEEP_NONINTERACTIVE;
- } else
-
- /*
- * Tasks that have marked their sleep as noninteractive get
- * woken up with their sleep average not weighted in an
- * interactive way.
- */
- if (old_state & TASK_NONINTERACTIVE)
- p->sleep_type = SLEEP_NONINTERACTIVE;
-
-
- activate_task(p, rq, cpu == this_cpu);
+ activate_task(rq, p, 1);
/*
* Sync wakeups (i.e. those types of wakeups where the waker
* has indicated that it will leave the CPU in short order)
* 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);
- }
+ if (!sync || cpu != this_cpu)
+ check_preempt_curr(rq, p);
success = 1;
out_running:
return try_to_wake_up(p, state, 0);
}
-static void task_running_tick(struct rq *rq, struct task_struct *p);
/*
* Perform scheduler related setup for a newly forked process p.
* p is forked by current.
- */
-void fastcall sched_fork(struct task_struct *p, int clone_flags)
-{
- int cpu = get_cpu();
+ *
+ * __sched_fork() is basic setup used by init_idle() too:
+ */
+static void __sched_fork(struct task_struct *p)
+{
+ p->se.wait_start_fair = 0;
+ p->se.wait_start = 0;
+ p->se.exec_start = 0;
+ p->se.sum_exec_runtime = 0;
+ p->se.delta_exec = 0;
+ p->se.delta_fair_run = 0;
+ p->se.delta_fair_sleep = 0;
+ p->se.wait_runtime = 0;
+ p->se.sum_wait_runtime = 0;
+ p->se.sum_sleep_runtime = 0;
+ p->se.sleep_start = 0;
+ p->se.sleep_start_fair = 0;
+ p->se.block_start = 0;
+ p->se.sleep_max = 0;
+ p->se.block_max = 0;
+ p->se.exec_max = 0;
+ p->se.wait_max = 0;
+ p->se.wait_runtime_overruns = 0;
+ p->se.wait_runtime_underruns = 0;
-#ifdef CONFIG_SMP
- cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
-#endif
- set_task_cpu(p, cpu);
+ INIT_LIST_HEAD(&p->run_list);
+ p->se.on_rq = 0;
/*
* We mark the process as running here, but have not actually
* event cannot wake it up and insert it on the runqueue either.
*/
p->state = TASK_RUNNING;
+}
+
+/*
+ * fork()/clone()-time setup:
+ */
+void sched_fork(struct task_struct *p, int clone_flags)
+{
+ int cpu = get_cpu();
+
+ __sched_fork(p);
+
+#ifdef CONFIG_SMP
+ cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
+#endif
+ __set_task_cpu(p, cpu);
/*
* Make sure we do not leak PI boosting priority to the child:
*/
p->prio = current->normal_prio;
- INIT_LIST_HEAD(&p->run_list);
- p->array = NULL;
#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
- if (unlikely(sched_info_on()))
+ if (likely(sched_info_on()))
memset(&p->sched_info, 0, sizeof(p->sched_info));
#endif
#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
/* 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;
- task_running_tick(cpu_rq(cpu), current);
- }
- local_irq_enable();
put_cpu();
}
/*
+ * After fork, child runs first. (default) If set to 0 then
+ * parent will (try to) run first.
+ */
+unsigned int __read_mostly sysctl_sched_child_runs_first = 1;
+
+/*
* wake_up_new_task - wake up a newly created task for the first time.
*
* This function will do some initial scheduler statistics housekeeping
*/
void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
{
- struct rq *rq, *this_rq;
unsigned long flags;
- int this_cpu, cpu;
+ struct rq *rq;
+ int this_cpu;
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);
+ this_cpu = smp_processor_id(); /* parent's CPU */
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;
- p->normal_prio = current->normal_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;
+ if (!sysctl_sched_child_runs_first || (clone_flags & CLONE_VM) ||
+ task_cpu(p) != this_cpu || !current->se.on_rq) {
+ activate_task(rq, p, 0);
} else {
- this_rq = cpu_rq(this_cpu);
-
/*
- * Not the local CPU - must adjust timestamp. This should
- * get optimised away in the !CONFIG_SMP case.
+ * Let the scheduling class do new task startup
+ * management (if any):
*/
- p->timestamp = (p->timestamp - this_rq->most_recent_timestamp)
- + rq->most_recent_timestamp;
- __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(struct task_struct *p)
-{
- unsigned long flags;
- struct rq *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);
+ p->sched_class->task_new(rq, 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);
+ check_preempt_curr(rq, p);
task_rq_unlock(rq, &flags);
}
/*
* Remove function-return probe instances associated with this
* task and put them back on the free list.
- */
+ */
kprobe_flush_task(prev);
put_task_struct(prev);
}
* context_switch - switch to the new MM and the new
* thread's register state.
*/
-static inline struct task_struct *
+static inline void
context_switch(struct rq *rq, struct task_struct *prev,
struct task_struct *next)
{
- struct mm_struct *mm = next->mm;
- struct mm_struct *oldmm = prev->active_mm;
+ struct mm_struct *mm, *oldmm;
+ prepare_task_switch(rq, next);
+ mm = next->mm;
+ oldmm = prev->active_mm;
/*
* For paravirt, this is coupled with an exit in switch_to to
* combine the page table reload and the switch backend into
*/
arch_enter_lazy_cpu_mode();
- if (!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 (!prev->mm) {
+ 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;
+ 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);
}
/*
return running + uninterruptible;
}
-#ifdef CONFIG_SMP
-
/*
- * Is this task likely cache-hot:
+ * Update rq->cpu_load[] statistics. This function is usually called every
+ * scheduler tick (TICK_NSEC).
*/
-static inline int
-task_hot(struct task_struct *p, unsigned long long now, struct sched_domain *sd)
+static void update_cpu_load(struct rq *this_rq)
{
- return (long long)(now - p->last_ran) < (long long)sd->cache_hot_time;
+ u64 fair_delta64, exec_delta64, idle_delta64, sample_interval64, tmp64;
+ unsigned long total_load = this_rq->ls.load.weight;
+ unsigned long this_load = total_load;
+ struct load_stat *ls = &this_rq->ls;
+ u64 now = __rq_clock(this_rq);
+ int i, scale;
+
+ this_rq->nr_load_updates++;
+ if (unlikely(!(sysctl_sched_features & SCHED_FEAT_PRECISE_CPU_LOAD)))
+ goto do_avg;
+
+ /* Update delta_fair/delta_exec fields first */
+ update_curr_load(this_rq, now);
+
+ fair_delta64 = ls->delta_fair + 1;
+ ls->delta_fair = 0;
+
+ exec_delta64 = ls->delta_exec + 1;
+ ls->delta_exec = 0;
+
+ sample_interval64 = now - ls->load_update_last;
+ ls->load_update_last = now;
+
+ if ((s64)sample_interval64 < (s64)TICK_NSEC)
+ sample_interval64 = TICK_NSEC;
+
+ if (exec_delta64 > sample_interval64)
+ exec_delta64 = sample_interval64;
+
+ idle_delta64 = sample_interval64 - exec_delta64;
+
+ tmp64 = div64_64(SCHED_LOAD_SCALE * exec_delta64, fair_delta64);
+ tmp64 = div64_64(tmp64 * exec_delta64, sample_interval64);
+
+ this_load = (unsigned long)tmp64;
+
+do_avg:
+
+ /* Update our load: */
+ for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
+ unsigned long old_load, new_load;
+
+ /* scale is effectively 1 << i now, and >> i divides by scale */
+
+ old_load = this_rq->cpu_load[i];
+ new_load = this_load;
+
+ this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
+ }
}
+#ifdef CONFIG_SMP
+
/*
* double_rq_lock - safely lock two runqueues
*
* pull_task - move a task from a remote runqueue to the local runqueue.
* Both runqueues must be locked.
*/
-static void pull_task(struct rq *src_rq, struct prio_array *src_array,
- struct task_struct *p, struct rq *this_rq,
- struct prio_array *this_array, int this_cpu)
+static void pull_task(struct rq *src_rq, struct task_struct *p,
+ struct rq *this_rq, int this_cpu)
{
- dequeue_task(p, src_array);
- dec_nr_running(p, src_rq);
+ deactivate_task(src_rq, p, 0);
set_task_cpu(p, this_cpu);
- inc_nr_running(p, this_rq);
- enqueue_task(p, this_array);
- p->timestamp = (p->timestamp - src_rq->most_recent_timestamp)
- + this_rq->most_recent_timestamp;
+ activate_task(this_rq, p, 0);
/*
* Note that idle threads have a prio of MAX_PRIO, for this test
* to be always true for them.
*/
- if (TASK_PREEMPTS_CURR(p, this_rq))
- resched_task(this_rq->curr);
+ check_preempt_curr(this_rq, p);
}
/*
*/
static
int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
- struct sched_domain *sd, enum idle_type idle,
+ struct sched_domain *sd, enum cpu_idle_type idle,
int *all_pinned)
{
/*
return 0;
/*
- * Aggressive migration if:
- * 1) task is cache cold, or
- * 2) too many balance attempts have failed.
+ * Aggressive migration if too many balance attempts have failed:
*/
-
- if (sd->nr_balance_failed > sd->cache_nice_tries) {
-#ifdef CONFIG_SCHEDSTATS
- if (task_hot(p, rq->most_recent_timestamp, sd))
- schedstat_inc(sd, lb_hot_gained[idle]);
-#endif
+ if (sd->nr_balance_failed > sd->cache_nice_tries)
return 1;
- }
- if (task_hot(p, rq->most_recent_timestamp, sd))
- return 0;
return 1;
}
-#define rq_best_prio(rq) min((rq)->curr->prio, (rq)->best_expired_prio)
-
-/*
- * move_tasks tries to move up to max_nr_move tasks and max_load_move weighted
- * load 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(struct rq *this_rq, int this_cpu, struct rq *busiest,
+static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
unsigned long max_nr_move, unsigned long max_load_move,
- struct sched_domain *sd, enum idle_type idle,
- int *all_pinned)
+ struct sched_domain *sd, enum cpu_idle_type idle,
+ int *all_pinned, unsigned long *load_moved,
+ int this_best_prio, int best_prio, int best_prio_seen,
+ struct rq_iterator *iterator)
{
- int idx, pulled = 0, pinned = 0, this_best_prio, best_prio,
- best_prio_seen, skip_for_load;
- struct prio_array *array, *dst_array;
- struct list_head *head, *curr;
- struct task_struct *tmp;
- long rem_load_move;
+ int pulled = 0, pinned = 0, skip_for_load;
+ struct task_struct *p;
+ long rem_load_move = max_load_move;
if (max_nr_move == 0 || max_load_move == 0)
goto out;
- rem_load_move = max_load_move;
pinned = 1;
- this_best_prio = rq_best_prio(this_rq);
- best_prio = rq_best_prio(busiest);
- /*
- * Enable handling of the case where there is more than one task
- * with the best priority. If the current running task is one
- * of those with prio==best_prio we know it won't be moved
- * and therefore it's safe to override the skip (based on load) of
- * any task we find with that prio.
- */
- best_prio_seen = best_prio == busiest->curr->prio;
/*
- * 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.
+ * Start the load-balancing iterator:
*/
- 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;
- }
+ p = iterator->start(iterator->arg);
+next:
+ if (!p)
goto out;
- }
-
- head = array->queue + idx;
- curr = head->prev;
-skip_queue:
- tmp = list_entry(curr, struct task_struct, run_list);
-
- curr = curr->prev;
-
/*
* To help distribute high priority tasks accross CPUs we don't
* skip a task if it will be the highest priority task (i.e. smallest
* prio value) on its new queue regardless of its load weight
*/
- skip_for_load = tmp->load_weight > rem_load_move;
- if (skip_for_load && idx < this_best_prio)
- skip_for_load = !best_prio_seen && idx == best_prio;
+ skip_for_load = (p->se.load.weight >> 1) > rem_load_move +
+ SCHED_LOAD_SCALE_FUZZ;
+ if (skip_for_load && p->prio < this_best_prio)
+ skip_for_load = !best_prio_seen && p->prio == best_prio;
if (skip_for_load ||
- !can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) {
+ !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
- best_prio_seen |= idx == best_prio;
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
+ best_prio_seen |= p->prio == best_prio;
+ p = iterator->next(iterator->arg);
+ goto next;
}
- pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu);
+ pull_task(busiest, p, this_rq, this_cpu);
pulled++;
- rem_load_move -= tmp->load_weight;
+ rem_load_move -= p->se.load.weight;
/*
* We only want to steal up to the prescribed number of tasks
* and the prescribed amount of weighted load.
*/
if (pulled < max_nr_move && rem_load_move > 0) {
- if (idx < this_best_prio)
- this_best_prio = idx;
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
+ if (p->prio < this_best_prio)
+ this_best_prio = p->prio;
+ p = iterator->next(iterator->arg);
+ goto next;
}
out:
/*
if (all_pinned)
*all_pinned = pinned;
+ *load_moved = max_load_move - rem_load_move;
return pulled;
}
/*
+ * move_tasks tries to move up to max_nr_move tasks and max_load_move weighted
+ * load 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(struct rq *this_rq, int this_cpu, struct rq *busiest,
+ unsigned long max_nr_move, unsigned long max_load_move,
+ struct sched_domain *sd, enum cpu_idle_type idle,
+ int *all_pinned)
+{
+ struct sched_class *class = sched_class_highest;
+ unsigned long load_moved, total_nr_moved = 0, nr_moved;
+ long rem_load_move = max_load_move;
+
+ do {
+ nr_moved = class->load_balance(this_rq, this_cpu, busiest,
+ max_nr_move, (unsigned long)rem_load_move,
+ sd, idle, all_pinned, &load_moved);
+ total_nr_moved += nr_moved;
+ max_nr_move -= nr_moved;
+ rem_load_move -= load_moved;
+ class = class->next;
+ } while (class && max_nr_move && rem_load_move > 0);
+
+ return total_nr_moved;
+}
+
+/*
* find_busiest_group finds and returns the busiest CPU group within the
* domain. It calculates and returns the amount of weighted load which
* should be moved to restore balance via the imbalance parameter.
*/
static struct sched_group *
find_busiest_group(struct sched_domain *sd, int this_cpu,
- unsigned long *imbalance, enum idle_type idle, int *sd_idle,
- cpumask_t *cpus, int *balance)
+ unsigned long *imbalance, enum cpu_idle_type idle,
+ int *sd_idle, cpumask_t *cpus, int *balance)
{
struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
unsigned long max_load, avg_load, total_load, this_load, total_pwr;
max_load = this_load = total_load = total_pwr = 0;
busiest_load_per_task = busiest_nr_running = 0;
this_load_per_task = this_nr_running = 0;
- if (idle == NOT_IDLE)
+ if (idle == CPU_NOT_IDLE)
load_idx = sd->busy_idx;
- else if (idle == NEWLY_IDLE)
+ else if (idle == CPU_NEWLY_IDLE)
load_idx = sd->newidle_idx;
else
load_idx = sd->idle_idx;
avg_load += load;
sum_nr_running += rq->nr_running;
- sum_weighted_load += rq->raw_weighted_load;
+ sum_weighted_load += weighted_cpuload(i);
}
/*
}
total_load += avg_load;
- total_pwr += group->cpu_power;
+ total_pwr += group->__cpu_power;
/* Adjust by relative CPU power of the group */
- avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power;
+ avg_load = sg_div_cpu_power(group,
+ avg_load * SCHED_LOAD_SCALE);
- group_capacity = group->cpu_power / SCHED_LOAD_SCALE;
+ group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
if (local_group) {
this_load = avg_load;
* Busy processors will not participate in power savings
* balance.
*/
- if (idle == NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
- goto group_next;
+ if (idle == CPU_NOT_IDLE ||
+ !(sd->flags & SD_POWERSAVINGS_BALANCE))
+ goto group_next;
/*
* If the local group is idle or completely loaded
!this_nr_running))
power_savings_balance = 0;
- /*
+ /*
* If a group is already running at full capacity or idle,
* don't include that group in power savings calculations
- */
- if (!power_savings_balance || sum_nr_running >= group_capacity
+ */
+ if (!power_savings_balance || sum_nr_running >= group_capacity
|| !sum_nr_running)
- goto group_next;
+ goto group_next;
- /*
+ /*
* Calculate the group which has the least non-idle load.
- * This is the group from where we need to pick up the load
- * for saving power
- */
- if ((sum_nr_running < min_nr_running) ||
- (sum_nr_running == min_nr_running &&
+ * This is the group from where we need to pick up the load
+ * for saving power
+ */
+ if ((sum_nr_running < min_nr_running) ||
+ (sum_nr_running == min_nr_running &&
first_cpu(group->cpumask) <
first_cpu(group_min->cpumask))) {
- group_min = group;
- min_nr_running = sum_nr_running;
+ group_min = group;
+ min_nr_running = sum_nr_running;
min_load_per_task = sum_weighted_load /
sum_nr_running;
- }
+ }
- /*
+ /*
* Calculate the group which is almost near its
- * capacity but still has some space to pick up some load
- * from other group and save more power
- */
- if (sum_nr_running <= group_capacity - 1) {
- if (sum_nr_running > leader_nr_running ||
- (sum_nr_running == leader_nr_running &&
- first_cpu(group->cpumask) >
- first_cpu(group_leader->cpumask))) {
- group_leader = group;
- leader_nr_running = sum_nr_running;
- }
+ * capacity but still has some space to pick up some load
+ * from other group and save more power
+ */
+ if (sum_nr_running <= group_capacity - 1) {
+ if (sum_nr_running > leader_nr_running ||
+ (sum_nr_running == leader_nr_running &&
+ first_cpu(group->cpumask) >
+ first_cpu(group_leader->cpumask))) {
+ group_leader = group;
+ leader_nr_running = sum_nr_running;
+ }
}
group_next:
#endif
max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
/* How much load to actually move to equalise the imbalance */
- *imbalance = min(max_pull * busiest->cpu_power,
- (avg_load - this_load) * this->cpu_power)
+ *imbalance = min(max_pull * busiest->__cpu_power,
+ (avg_load - this_load) * this->__cpu_power)
/ SCHED_LOAD_SCALE;
/*
* a think about bumping its value to force at least one task to be
* moved
*/
- if (*imbalance < busiest_load_per_task) {
+ if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task/2) {
unsigned long tmp, pwr_now, pwr_move;
unsigned int imbn;
} else
this_load_per_task = SCHED_LOAD_SCALE;
- if (max_load - this_load >= busiest_load_per_task * imbn) {
+ if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >=
+ busiest_load_per_task * imbn) {
*imbalance = busiest_load_per_task;
return busiest;
}
* moving them.
*/
- pwr_now += busiest->cpu_power *
- min(busiest_load_per_task, max_load);
- pwr_now += this->cpu_power *
- min(this_load_per_task, this_load);
+ pwr_now += busiest->__cpu_power *
+ min(busiest_load_per_task, max_load);
+ pwr_now += this->__cpu_power *
+ min(this_load_per_task, this_load);
pwr_now /= SCHED_LOAD_SCALE;
/* Amount of load we'd subtract */
- tmp = busiest_load_per_task * SCHED_LOAD_SCALE /
- busiest->cpu_power;
+ tmp = sg_div_cpu_power(busiest,
+ busiest_load_per_task * SCHED_LOAD_SCALE);
if (max_load > tmp)
- pwr_move += busiest->cpu_power *
+ pwr_move += busiest->__cpu_power *
min(busiest_load_per_task, max_load - tmp);
/* Amount of load we'd add */
- if (max_load * busiest->cpu_power <
+ if (max_load * busiest->__cpu_power <
busiest_load_per_task * SCHED_LOAD_SCALE)
- tmp = max_load * busiest->cpu_power / this->cpu_power;
+ tmp = sg_div_cpu_power(this,
+ max_load * busiest->__cpu_power);
else
- tmp = busiest_load_per_task * SCHED_LOAD_SCALE /
- this->cpu_power;
- pwr_move += this->cpu_power *
- min(this_load_per_task, this_load + tmp);
+ tmp = sg_div_cpu_power(this,
+ busiest_load_per_task * SCHED_LOAD_SCALE);
+ pwr_move += this->__cpu_power *
+ min(this_load_per_task, this_load + tmp);
pwr_move /= SCHED_LOAD_SCALE;
/* Move if we gain throughput */
out_balanced:
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- if (idle == NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
+ if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
goto ret;
if (this == group_leader && group_leader != group_min) {
* find_busiest_queue - find the busiest runqueue among the cpus in group.
*/
static struct rq *
-find_busiest_queue(struct sched_group *group, enum idle_type idle,
+find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
unsigned long imbalance, cpumask_t *cpus)
{
struct rq *busiest = NULL, *rq;
int i;
for_each_cpu_mask(i, group->cpumask) {
+ unsigned long wl;
if (!cpu_isset(i, *cpus))
continue;
rq = cpu_rq(i);
+ wl = weighted_cpuload(i);
- if (rq->nr_running == 1 && rq->raw_weighted_load > imbalance)
+ if (rq->nr_running == 1 && wl > imbalance)
continue;
- if (rq->raw_weighted_load > max_load) {
- max_load = rq->raw_weighted_load;
+ if (wl > max_load) {
+ max_load = wl;
busiest = rq;
}
}
* tasks if there is an imbalance.
*/
static int load_balance(int this_cpu, struct rq *this_rq,
- struct sched_domain *sd, enum idle_type idle,
+ struct sched_domain *sd, enum cpu_idle_type idle,
int *balance)
{
int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
/*
* When power savings policy is enabled for the parent domain, idle
* sibling can pick up load irrespective of busy siblings. In this case,
- * let the state of idle sibling percolate up as IDLE, instead of
- * portraying it as NOT_IDLE.
+ * let the state of idle sibling percolate up as CPU_IDLE, instead of
+ * portraying it as CPU_NOT_IDLE.
*/
- if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
+ if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
sd_idle = 1;
double_rq_unlock(this_rq, busiest);
local_irq_restore(flags);
+ /*
+ * some other cpu did the load balance for us.
+ */
+ if (nr_moved && this_cpu != smp_processor_id())
+ resched_cpu(this_cpu);
+
/* All tasks on this runqueue were pinned by CPU affinity */
if (unlikely(all_pinned)) {
cpu_clear(cpu_of(busiest), cpus);
* 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).
+ * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
* this_rq is locked.
*/
static int
* When power savings policy is enabled for the parent domain, idle
* sibling can pick up load irrespective of busy siblings. In this case,
* let the state of idle sibling percolate up as IDLE, instead of
- * portraying it as NOT_IDLE.
+ * portraying it as CPU_NOT_IDLE.
*/
if (sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
sd_idle = 1;
- schedstat_inc(sd, lb_cnt[NEWLY_IDLE]);
+ schedstat_inc(sd, lb_cnt[CPU_NEWLY_IDLE]);
redo:
- group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE,
+ group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
&sd_idle, &cpus, NULL);
if (!group) {
- schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]);
+ schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
goto out_balanced;
}
- busiest = find_busiest_queue(group, NEWLY_IDLE, imbalance,
+ busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance,
&cpus);
if (!busiest) {
- schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]);
+ schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
goto out_balanced;
}
BUG_ON(busiest == this_rq);
- schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance);
+ schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
nr_moved = 0;
if (busiest->nr_running > 1) {
double_lock_balance(this_rq, busiest);
nr_moved = move_tasks(this_rq, this_cpu, busiest,
minus_1_or_zero(busiest->nr_running),
- imbalance, sd, NEWLY_IDLE, NULL);
+ imbalance, sd, CPU_NEWLY_IDLE, NULL);
spin_unlock(&busiest->lock);
if (!nr_moved) {
}
if (!nr_moved) {
- schedstat_inc(sd, lb_failed[NEWLY_IDLE]);
+ schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
return -1;
return nr_moved;
out_balanced:
- schedstat_inc(sd, lb_balanced[NEWLY_IDLE]);
+ schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
return -1;
static void idle_balance(int this_cpu, struct rq *this_rq)
{
struct sched_domain *sd;
- int pulled_task = 0;
- unsigned long next_balance = jiffies + 60 * HZ;
+ int pulled_task = -1;
+ unsigned long next_balance = jiffies + HZ;
for_each_domain(this_cpu, sd) {
- if (sd->flags & SD_BALANCE_NEWIDLE) {
+ unsigned long interval;
+
+ if (!(sd->flags & SD_LOAD_BALANCE))
+ continue;
+
+ if (sd->flags & SD_BALANCE_NEWIDLE)
/* If we've pulled tasks over stop searching: */
pulled_task = load_balance_newidle(this_cpu,
- this_rq, sd);
- if (time_after(next_balance,
- sd->last_balance + sd->balance_interval))
- next_balance = sd->last_balance
- + sd->balance_interval;
- if (pulled_task)
- break;
- }
+ this_rq, sd);
+
+ interval = msecs_to_jiffies(sd->balance_interval);
+ if (time_after(next_balance, sd->last_balance + interval))
+ next_balance = sd->last_balance + interval;
+ if (pulled_task)
+ break;
}
- if (!pulled_task)
+ if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
/*
* We are going idle. next_balance may be set based on
* a busy processor. So reset next_balance.
*/
this_rq->next_balance = next_balance;
+ }
}
/*
schedstat_inc(sd, alb_cnt);
if (move_tasks(target_rq, target_cpu, busiest_rq, 1,
- RTPRIO_TO_LOAD_WEIGHT(100), sd, SCHED_IDLE,
+ RTPRIO_TO_LOAD_WEIGHT(100), sd, CPU_IDLE,
NULL))
schedstat_inc(sd, alb_pushed);
else
spin_unlock(&target_rq->lock);
}
-static void update_load(struct rq *this_rq)
-{
- unsigned long this_load;
- unsigned int i, scale;
-
- this_load = this_rq->raw_weighted_load;
+#ifdef CONFIG_NO_HZ
+static struct {
+ atomic_t load_balancer;
+ cpumask_t cpu_mask;
+} nohz ____cacheline_aligned = {
+ .load_balancer = ATOMIC_INIT(-1),
+ .cpu_mask = CPU_MASK_NONE,
+};
- /* Update our load: */
- for (i = 0, scale = 1; i < 3; i++, scale += scale) {
- unsigned long old_load, new_load;
+/*
+ * This routine will try to nominate the ilb (idle load balancing)
+ * owner among the cpus whose ticks are stopped. ilb owner will do the idle
+ * load balancing on behalf of all those cpus. If all the cpus in the system
+ * go into this tickless mode, then there will be no ilb owner (as there is
+ * no need for one) and all the cpus will sleep till the next wakeup event
+ * arrives...
+ *
+ * For the ilb owner, tick is not stopped. And this tick will be used
+ * for idle load balancing. ilb owner will still be part of
+ * nohz.cpu_mask..
+ *
+ * While stopping the tick, this cpu will become the ilb owner if there
+ * is no other owner. And will be the owner till that cpu becomes busy
+ * or if all cpus in the system stop their ticks at which point
+ * there is no need for ilb owner.
+ *
+ * When the ilb owner becomes busy, it nominates another owner, during the
+ * next busy scheduler_tick()
+ */
+int select_nohz_load_balancer(int stop_tick)
+{
+ int cpu = smp_processor_id();
- /* scale is effectively 1 << i now, and >> i divides by scale */
+ if (stop_tick) {
+ cpu_set(cpu, nohz.cpu_mask);
+ cpu_rq(cpu)->in_nohz_recently = 1;
- old_load = this_rq->cpu_load[i];
- new_load = this_load;
/*
- * Round up the averaging division if load is increasing. This
- * prevents us from getting stuck on 9 if the load is 10, for
- * example.
+ * If we are going offline and still the leader, give up!
*/
- if (new_load > old_load)
- new_load += scale-1;
- this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
+ if (cpu_is_offline(cpu) &&
+ atomic_read(&nohz.load_balancer) == cpu) {
+ if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
+ BUG();
+ return 0;
+ }
+
+ /* time for ilb owner also to sleep */
+ if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
+ if (atomic_read(&nohz.load_balancer) == cpu)
+ atomic_set(&nohz.load_balancer, -1);
+ return 0;
+ }
+
+ if (atomic_read(&nohz.load_balancer) == -1) {
+ /* make me the ilb owner */
+ if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
+ return 1;
+ } else if (atomic_read(&nohz.load_balancer) == cpu)
+ return 1;
+ } else {
+ if (!cpu_isset(cpu, nohz.cpu_mask))
+ return 0;
+
+ cpu_clear(cpu, nohz.cpu_mask);
+
+ if (atomic_read(&nohz.load_balancer) == cpu)
+ if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
+ BUG();
}
+ return 0;
}
+#endif
+
+static DEFINE_SPINLOCK(balancing);
/*
- * run_rebalance_domains is triggered when needed from the scheduler tick.
- *
* It checks each scheduling domain to see if it is due to be balanced,
* and initiates a balancing operation if so.
*
* Balancing parameters are set up in arch_init_sched_domains.
- */
-static DEFINE_SPINLOCK(balancing);
-
-static void run_rebalance_domains(struct softirq_action *h)
+ */
+static inline void rebalance_domains(int cpu, enum cpu_idle_type idle)
{
- int this_cpu = smp_processor_id(), balance = 1;
- struct rq *this_rq = cpu_rq(this_cpu);
+ int balance = 1;
+ struct rq *rq = cpu_rq(cpu);
unsigned long interval;
struct sched_domain *sd;
- /*
- * We are idle if there are no processes running. This
- * is valid even if we are the idle process (SMT).
- */
- enum idle_type idle = !this_rq->nr_running ?
- SCHED_IDLE : NOT_IDLE;
- /* Earliest time when we have to call run_rebalance_domains again */
+ /* Earliest time when we have to do rebalance again */
unsigned long next_balance = jiffies + 60*HZ;
- for_each_domain(this_cpu, sd) {
+ for_each_domain(cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
continue;
interval = sd->balance_interval;
- if (idle != SCHED_IDLE)
+ if (idle != CPU_IDLE)
interval *= sd->busy_factor;
/* scale ms to jiffies */
interval = msecs_to_jiffies(interval);
if (unlikely(!interval))
interval = 1;
+ if (interval > HZ*NR_CPUS/10)
+ interval = HZ*NR_CPUS/10;
+
if (sd->flags & SD_SERIALIZE) {
if (!spin_trylock(&balancing))
}
if (time_after_eq(jiffies, sd->last_balance + interval)) {
- if (load_balance(this_cpu, this_rq, sd, idle, &balance)) {
+ if (load_balance(cpu, rq, sd, idle, &balance)) {
/*
* We've pulled tasks over so either we're no
* longer idle, or one of our SMT siblings is
* not idle.
*/
- idle = NOT_IDLE;
+ idle = CPU_NOT_IDLE;
}
sd->last_balance = jiffies;
}
if (!balance)
break;
}
- this_rq->next_balance = next_balance;
+ rq->next_balance = next_balance;
}
-#else
+
/*
- * on UP we do not need to balance between CPUs:
+ * run_rebalance_domains is triggered when needed from the scheduler tick.
+ * In CONFIG_NO_HZ case, the idle load balance owner will do the
+ * rebalancing for all the cpus for whom scheduler ticks are stopped.
*/
-static inline void idle_balance(int cpu, struct rq *rq)
+static void run_rebalance_domains(struct softirq_action *h)
{
-}
-#endif
+ int this_cpu = smp_processor_id();
+ struct rq *this_rq = cpu_rq(this_cpu);
+ enum cpu_idle_type idle = this_rq->idle_at_tick ?
+ CPU_IDLE : CPU_NOT_IDLE;
-DEFINE_PER_CPU(struct kernel_stat, kstat);
+ rebalance_domains(this_cpu, idle);
-EXPORT_PER_CPU_SYMBOL(kstat);
+#ifdef CONFIG_NO_HZ
+ /*
+ * If this cpu is the owner for idle load balancing, then do the
+ * balancing on behalf of the other idle cpus whose ticks are
+ * stopped.
+ */
+ if (this_rq->idle_at_tick &&
+ atomic_read(&nohz.load_balancer) == this_cpu) {
+ cpumask_t cpus = nohz.cpu_mask;
+ struct rq *rq;
+ int balance_cpu;
+
+ cpu_clear(this_cpu, cpus);
+ for_each_cpu_mask(balance_cpu, cpus) {
+ /*
+ * If this cpu gets work to do, stop the load balancing
+ * work being done for other cpus. Next load
+ * balancing owner will pick it up.
+ */
+ if (need_resched())
+ break;
+
+ rebalance_domains(balance_cpu, SCHED_IDLE);
+
+ rq = cpu_rq(balance_cpu);
+ if (time_after(this_rq->next_balance, rq->next_balance))
+ this_rq->next_balance = rq->next_balance;
+ }
+ }
+#endif
+}
/*
- * This is called on clock ticks and on context switches.
- * Bank in p->sched_time the ns elapsed since the last tick or switch.
+ * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
+ *
+ * In case of CONFIG_NO_HZ, this is the place where we nominate a new
+ * idle load balancing owner or decide to stop the periodic load balancing,
+ * if the whole system is idle.
*/
-static inline void
-update_cpu_clock(struct task_struct *p, struct rq *rq, unsigned long long now)
+static inline void trigger_load_balance(struct rq *rq, int cpu)
{
- p->sched_time += now - p->last_ran;
- p->last_ran = rq->most_recent_timestamp = now;
+#ifdef CONFIG_NO_HZ
+ /*
+ * If we were in the nohz mode recently and busy at the current
+ * scheduler tick, then check if we need to nominate new idle
+ * load balancer.
+ */
+ if (rq->in_nohz_recently && !rq->idle_at_tick) {
+ rq->in_nohz_recently = 0;
+
+ if (atomic_read(&nohz.load_balancer) == cpu) {
+ cpu_clear(cpu, nohz.cpu_mask);
+ atomic_set(&nohz.load_balancer, -1);
+ }
+
+ if (atomic_read(&nohz.load_balancer) == -1) {
+ /*
+ * simple selection for now: Nominate the
+ * first cpu in the nohz list to be the next
+ * ilb owner.
+ *
+ * TBD: Traverse the sched domains and nominate
+ * the nearest cpu in the nohz.cpu_mask.
+ */
+ int ilb = first_cpu(nohz.cpu_mask);
+
+ if (ilb != NR_CPUS)
+ resched_cpu(ilb);
+ }
+ }
+
+ /*
+ * If this cpu is idle and doing idle load balancing for all the
+ * cpus with ticks stopped, is it time for that to stop?
+ */
+ if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
+ cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
+ resched_cpu(cpu);
+ return;
+ }
+
+ /*
+ * If this cpu is idle and the idle load balancing is done by
+ * someone else, then no need raise the SCHED_SOFTIRQ
+ */
+ if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
+ cpu_isset(cpu, nohz.cpu_mask))
+ return;
+#endif
+ if (time_after_eq(jiffies, rq->next_balance))
+ raise_softirq(SCHED_SOFTIRQ);
}
+#else /* CONFIG_SMP */
+
/*
- * Return current->sched_time plus any more ns on the sched_clock
- * that have not yet been banked.
+ * on UP we do not need to balance between CPUs:
*/
-unsigned long long current_sched_time(const struct task_struct *p)
+static inline void idle_balance(int cpu, struct rq *rq)
{
- unsigned long long ns;
- unsigned long flags;
+}
- local_irq_save(flags);
- ns = p->sched_time + sched_clock() - p->last_ran;
- local_irq_restore(flags);
+/* Avoid "used but not defined" warning on UP */
+static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+ unsigned long max_nr_move, unsigned long max_load_move,
+ struct sched_domain *sd, enum cpu_idle_type idle,
+ int *all_pinned, unsigned long *load_moved,
+ int this_best_prio, int best_prio, int best_prio_seen,
+ struct rq_iterator *iterator)
+{
+ *load_moved = 0;
- return ns;
+ return 0;
}
+#endif
+
+DEFINE_PER_CPU(struct kernel_stat, kstat);
+
+EXPORT_PER_CPU_SYMBOL(kstat);
+
/*
- * 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:
+ * Return p->sum_exec_runtime plus any more ns on the sched_clock
+ * that have not yet been banked in case the task is currently running.
*/
-static inline int expired_starving(struct rq *rq)
+unsigned long long task_sched_runtime(struct task_struct *p)
{
- if (rq->curr->static_prio > rq->best_expired_prio)
- return 1;
- if (!STARVATION_LIMIT || !rq->expired_timestamp)
- return 0;
- if (jiffies - rq->expired_timestamp > STARVATION_LIMIT * rq->nr_running)
- return 1;
- return 0;
+ unsigned long flags;
+ u64 ns, delta_exec;
+ struct rq *rq;
+
+ rq = task_rq_lock(p, &flags);
+ ns = p->se.sum_exec_runtime;
+ if (rq->curr == p) {
+ delta_exec = rq_clock(rq) - p->se.exec_start;
+ if ((s64)delta_exec > 0)
+ ns += delta_exec;
+ }
+ task_rq_unlock(rq, &flags);
+
+ return ns;
}
/*
cpustat->steal = cputime64_add(cpustat->steal, tmp);
}
-static void task_running_tick(struct rq *rq, struct task_struct *p)
-{
- if (p->array != rq->active) {
- /* Task has expired but was not scheduled yet */
- set_tsk_need_resched(p);
- return;
- }
- 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);
-}
-
/*
* This function gets called by the timer code, with HZ frequency.
* We call it with interrupts disabled.
*/
void scheduler_tick(void)
{
- unsigned long long now = sched_clock();
- struct task_struct *p = current;
int cpu = smp_processor_id();
struct rq *rq = cpu_rq(cpu);
+ struct task_struct *curr = rq->curr;
- update_cpu_clock(p, rq, now);
+ spin_lock(&rq->lock);
+ if (curr != rq->idle) /* FIXME: needed? */
+ curr->sched_class->task_tick(rq, curr);
+ update_cpu_load(rq);
+ spin_unlock(&rq->lock);
- if (p != rq->idle)
- task_running_tick(rq, p);
#ifdef CONFIG_SMP
- update_load(rq);
- if (time_after_eq(jiffies, rq->next_balance))
- raise_softirq(SCHED_SOFTIRQ);
+ rq->idle_at_tick = idle_cpu(cpu);
+ trigger_load_balance(rq, cpu);
#endif
}
#endif
-static inline int interactive_sleep(enum sleep_type sleep_type)
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
{
- return (sleep_type == SLEEP_INTERACTIVE ||
- sleep_type == SLEEP_INTERRUPTED);
+ printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n",
+ prev->comm, preempt_count(), prev->pid);
+ debug_show_held_locks(prev);
+ if (irqs_disabled())
+ print_irqtrace_events(prev);
+ dump_stack();
}
/*
- * schedule() is the main scheduler function.
+ * Various schedule()-time debugging checks and statistics:
*/
-asmlinkage void __sched schedule(void)
+static inline void schedule_debug(struct task_struct *prev)
{
- struct task_struct *prev, *next;
- struct prio_array *array;
- struct list_head *queue;
- unsigned long long now;
- unsigned long run_time;
- int cpu, idx, new_prio;
- long *switch_count;
- struct rq *rq;
-
/*
* Test if we are atomic. Since do_exit() needs to call into
* schedule() atomically, we ignore that path for now.
* Otherwise, whine if we are scheduling when we should not be.
*/
- if (unlikely(in_atomic() && !current->exit_state)) {
- printk(KERN_ERR "BUG: scheduling while atomic: "
- "%s/0x%08x/%d\n",
- current->comm, preempt_count(), current->pid);
- debug_show_held_locks(current);
- if (irqs_disabled())
- print_irqtrace_events(current);
- dump_stack();
- }
- profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+ if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state))
+ __schedule_bug(prev);
-need_resched:
- preempt_disable();
- prev = current;
- release_kernel_lock(prev);
-need_resched_nonpreemptible:
- rq = this_rq();
+ profile_hit(SCHED_PROFILING, __builtin_return_address(0));
- /*
- * 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(this_rq(), sched_cnt);
+}
- 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;
+/*
+ * Pick up the highest-prio task:
+ */
+static inline struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev, u64 now)
+{
+ struct sched_class *class;
+ struct task_struct *p;
/*
- * Tasks charged proportionately less run_time at high sleep_avg to
- * delay them losing their interactive status
+ * Optimization: we know that if all tasks are in
+ * the fair class we can call that function directly:
*/
- run_time /= (CURRENT_BONUS(prev) ? : 1);
-
- spin_lock_irq(&rq->lock);
-
- 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)) {
- idle_balance(cpu, rq);
- if (!rq->nr_running) {
- next = rq->idle;
- rq->expired_timestamp = 0;
- goto switch_tasks;
- }
+ if (likely(rq->nr_running == rq->cfs.nr_running)) {
+ p = fair_sched_class.pick_next_task(rq, now);
+ if (likely(p))
+ return p;
}
- array = rq->active;
- if (unlikely(!array->nr_active)) {
+ class = sched_class_highest;
+ for ( ; ; ) {
+ p = class->pick_next_task(rq, now);
+ if (p)
+ return p;
/*
- * Switch the active and expired arrays.
+ * Will never be NULL as the idle class always
+ * returns a non-NULL p:
*/
- 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;
+ class = class->next;
}
+}
+
+/*
+ * schedule() is the main scheduler function.
+ */
+asmlinkage void __sched schedule(void)
+{
+ struct task_struct *prev, *next;
+ long *switch_count;
+ struct rq *rq;
+ u64 now;
+ int cpu;
- idx = sched_find_first_bit(array->bitmap);
- queue = array->queue + idx;
- next = list_entry(queue->next, struct task_struct, run_list);
+need_resched:
+ preempt_disable();
+ cpu = smp_processor_id();
+ rq = cpu_rq(cpu);
+ rcu_qsctr_inc(cpu);
+ prev = rq->curr;
+ switch_count = &prev->nivcsw;
- if (!rt_task(next) && interactive_sleep(next->sleep_type)) {
- unsigned long long delta = now - next->timestamp;
- if (unlikely((long long)(now - next->timestamp) < 0))
- delta = 0;
+ release_kernel_lock(prev);
+need_resched_nonpreemptible:
- if (next->sleep_type == SLEEP_INTERACTIVE)
- delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128;
+ schedule_debug(prev);
- array = next->array;
- new_prio = recalc_task_prio(next, next->timestamp + delta);
+ spin_lock_irq(&rq->lock);
+ clear_tsk_need_resched(prev);
- if (unlikely(next->prio != new_prio)) {
- dequeue_task(next, array);
- next->prio = new_prio;
- enqueue_task(next, array);
+ if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
+ if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
+ unlikely(signal_pending(prev)))) {
+ prev->state = TASK_RUNNING;
+ } else {
+ deactivate_task(rq, prev, 1);
}
+ switch_count = &prev->nvcsw;
}
- next->sleep_type = SLEEP_NORMAL;
-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);
+ if (unlikely(!rq->nr_running))
+ idle_balance(cpu, rq);
- prev->sleep_avg -= run_time;
- if ((long)prev->sleep_avg <= 0)
- prev->sleep_avg = 0;
- prev->timestamp = prev->last_ran = now;
+ now = __rq_clock(rq);
+ prev->sched_class->put_prev_task(rq, prev, now);
+ next = pick_next_task(rq, prev, now);
sched_info_switch(prev, next);
+
if (likely(prev != next)) {
- next->timestamp = next->last_ran = 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);
+ context_switch(rq, prev, next); /* unlocks the rq */
} else
spin_unlock_irq(&rq->lock);
- prev = current;
- if (unlikely(reacquire_kernel_lock(prev) < 0))
+ if (unlikely(reacquire_kernel_lock(current) < 0)) {
+ cpu = smp_processor_id();
+ rq = cpu_rq(cpu);
goto need_resched_nonpreemptible;
+ }
preempt_enable_no_resched();
if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
goto need_resched;
}
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); \
+static inline void
+sleep_on_head(wait_queue_head_t *q, wait_queue_t *wait, unsigned long *flags)
+{
+ 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);
+static inline void
+sleep_on_tail(wait_queue_head_t *q, wait_queue_t *wait, unsigned long *flags)
+{
+ 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)
+void __sched interruptible_sleep_on(wait_queue_head_t *q)
{
- SLEEP_ON_VAR
+ unsigned long flags;
+ wait_queue_t wait;
+
+ init_waitqueue_entry(&wait, current);
current->state = TASK_INTERRUPTIBLE;
- SLEEP_ON_HEAD
+ sleep_on_head(q, &wait, &flags);
schedule();
- SLEEP_ON_TAIL
+ sleep_on_tail(q, &wait, &flags);
}
EXPORT_SYMBOL(interruptible_sleep_on);
-long fastcall __sched
+long __sched
interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
- SLEEP_ON_VAR
+ unsigned long flags;
+ wait_queue_t wait;
+
+ init_waitqueue_entry(&wait, current);
current->state = TASK_INTERRUPTIBLE;
- SLEEP_ON_HEAD
+ sleep_on_head(q, &wait, &flags);
timeout = schedule_timeout(timeout);
- SLEEP_ON_TAIL
+ sleep_on_tail(q, &wait, &flags);
return timeout;
}
EXPORT_SYMBOL(interruptible_sleep_on_timeout);
-void fastcall __sched sleep_on(wait_queue_head_t *q)
+void __sched sleep_on(wait_queue_head_t *q)
{
- SLEEP_ON_VAR
+ unsigned long flags;
+ wait_queue_t wait;
+
+ init_waitqueue_entry(&wait, current);
current->state = TASK_UNINTERRUPTIBLE;
- SLEEP_ON_HEAD
+ sleep_on_head(q, &wait, &flags);
schedule();
- SLEEP_ON_TAIL
+ sleep_on_tail(q, &wait, &flags);
}
EXPORT_SYMBOL(sleep_on);
-long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
+long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
{
- SLEEP_ON_VAR
+ unsigned long flags;
+ wait_queue_t wait;
+
+ init_waitqueue_entry(&wait, current);
current->state = TASK_UNINTERRUPTIBLE;
- SLEEP_ON_HEAD
+ sleep_on_head(q, &wait, &flags);
timeout = schedule_timeout(timeout);
- SLEEP_ON_TAIL
+ sleep_on_tail(q, &wait, &flags);
return timeout;
}
-
EXPORT_SYMBOL(sleep_on_timeout);
#ifdef CONFIG_RT_MUTEXES
*/
void rt_mutex_setprio(struct task_struct *p, int prio)
{
- struct prio_array *array;
unsigned long flags;
+ int oldprio, on_rq;
struct rq *rq;
- int oldprio;
+ u64 now;
BUG_ON(prio < 0 || prio > MAX_PRIO);
rq = task_rq_lock(p, &flags);
+ now = rq_clock(rq);
oldprio = p->prio;
- array = p->array;
- if (array)
- dequeue_task(p, array);
+ on_rq = p->se.on_rq;
+ if (on_rq)
+ dequeue_task(rq, p, 0, now);
+
+ if (rt_prio(prio))
+ p->sched_class = &rt_sched_class;
+ else
+ p->sched_class = &fair_sched_class;
+
p->prio = prio;
- if (array) {
- /*
- * If changing to an RT priority then queue it
- * in the active array!
- */
- if (rt_task(p))
- array = rq->active;
- enqueue_task(p, array);
+ if (on_rq) {
+ enqueue_task(rq, p, 0, now);
/*
* Reschedule if we are currently running on this runqueue and
* our priority decreased, or if we are not currently running on
if (task_running(rq, p)) {
if (p->prio > oldprio)
resched_task(rq->curr);
- } else if (TASK_PREEMPTS_CURR(p, rq))
- resched_task(rq->curr);
+ } else {
+ check_preempt_curr(rq, p);
+ }
}
task_rq_unlock(rq, &flags);
}
void set_user_nice(struct task_struct *p, long nice)
{
- struct prio_array *array;
- int old_prio, delta;
+ int old_prio, delta, on_rq;
unsigned long flags;
struct rq *rq;
+ u64 now;
if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
return;
* the task might be in the middle of scheduling on another CPU.
*/
rq = task_rq_lock(p, &flags);
+ now = rq_clock(rq);
/*
* The RT priorities are set via sched_setscheduler(), but we still
* allow the 'normal' nice value to be set - but as expected
* it wont have any effect on scheduling until the task is
- * not SCHED_NORMAL/SCHED_BATCH:
+ * SCHED_FIFO/SCHED_RR:
*/
- if (has_rt_policy(p)) {
+ if (task_has_rt_policy(p)) {
p->static_prio = NICE_TO_PRIO(nice);
goto out_unlock;
}
- array = p->array;
- if (array) {
- dequeue_task(p, array);
- dec_raw_weighted_load(rq, p);
+ on_rq = p->se.on_rq;
+ if (on_rq) {
+ dequeue_task(rq, p, 0, now);
+ dec_load(rq, p, now);
}
p->static_prio = NICE_TO_PRIO(nice);
p->prio = effective_prio(p);
delta = p->prio - old_prio;
- if (array) {
- enqueue_task(p, array);
- inc_raw_weighted_load(rq, p);
+ if (on_rq) {
+ enqueue_task(rq, p, 0, now);
+ inc_load(rq, p, now);
/*
* If the task increased its priority or is running and
* lowered its priority, then reschedule its CPU:
}
/* Actually do priority change: must hold rq lock. */
-static void __setscheduler(struct task_struct *p, int policy, int prio)
+static void
+__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
{
- BUG_ON(p->array);
+ BUG_ON(p->se.on_rq);
p->policy = policy;
+ switch (p->policy) {
+ case SCHED_NORMAL:
+ case SCHED_BATCH:
+ case SCHED_IDLE:
+ p->sched_class = &fair_sched_class;
+ break;
+ case SCHED_FIFO:
+ case SCHED_RR:
+ p->sched_class = &rt_sched_class;
+ break;
+ }
+
p->rt_priority = prio;
p->normal_prio = normal_prio(p);
/* we are holding p->pi_lock already */
p->prio = rt_mutex_getprio(p);
- /*
- * SCHED_BATCH tasks are treated as perpetual CPU hogs:
- */
- if (policy == SCHED_BATCH)
- p->sleep_avg = 0;
set_load_weight(p);
}
int sched_setscheduler(struct task_struct *p, int policy,
struct sched_param *param)
{
- int retval, oldprio, oldpolicy = -1;
- struct prio_array *array;
+ int retval, oldprio, oldpolicy = -1, on_rq;
unsigned long flags;
struct rq *rq;
if (policy < 0)
policy = oldpolicy = p->policy;
else if (policy != SCHED_FIFO && policy != SCHED_RR &&
- policy != SCHED_NORMAL && policy != SCHED_BATCH)
+ policy != SCHED_NORMAL && policy != SCHED_BATCH &&
+ policy != SCHED_IDLE)
return -EINVAL;
/*
* Valid priorities for SCHED_FIFO and SCHED_RR are
- * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and
- * SCHED_BATCH is 0.
+ * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
+ * SCHED_BATCH and SCHED_IDLE is 0.
*/
if (param->sched_priority < 0 ||
(p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
(!p->mm && param->sched_priority > MAX_RT_PRIO-1))
return -EINVAL;
- if (is_rt_policy(policy) != (param->sched_priority != 0))
+ if (rt_policy(policy) != (param->sched_priority != 0))
return -EINVAL;
/*
* Allow unprivileged RT tasks to decrease priority:
*/
if (!capable(CAP_SYS_NICE)) {
- if (is_rt_policy(policy)) {
+ if (rt_policy(policy)) {
unsigned long rlim_rtprio;
- unsigned long flags;
if (!lock_task_sighand(p, &flags))
return -ESRCH;
param->sched_priority > rlim_rtprio)
return -EPERM;
}
+ /*
+ * Like positive nice levels, dont allow tasks to
+ * move out of SCHED_IDLE either:
+ */
+ if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
+ return -EPERM;
/* can't change other user's priorities */
if ((current->euid != p->euid) &&
spin_unlock_irqrestore(&p->pi_lock, flags);
goto recheck;
}
- array = p->array;
- if (array)
- deactivate_task(p, rq);
+ on_rq = p->se.on_rq;
+ if (on_rq)
+ deactivate_task(rq, p, 0);
oldprio = p->prio;
- __setscheduler(p, policy, param->sched_priority);
- if (array) {
- __activate_task(p, rq);
+ __setscheduler(rq, p, policy, param->sched_priority);
+ if (on_rq) {
+ activate_task(rq, p, 0);
/*
* Reschedule if we are currently running on this runqueue and
* our priority decreased, or if we are not currently running on
if (task_running(rq, p)) {
if (p->prio > oldprio)
resched_task(rq->curr);
- } else if (TASK_PREEMPTS_CURR(p, rq))
- resched_task(rq->curr);
+ } else {
+ check_preempt_curr(rq, p);
+ }
}
__task_rq_unlock(rq);
spin_unlock_irqrestore(&p->pi_lock, flags);
struct task_struct *p;
int retval;
- lock_cpu_hotplug();
+ mutex_lock(&sched_hotcpu_mutex);
read_lock(&tasklist_lock);
p = find_process_by_pid(pid);
if (!p) {
read_unlock(&tasklist_lock);
- unlock_cpu_hotplug();
+ mutex_unlock(&sched_hotcpu_mutex);
return -ESRCH;
}
out_unlock:
put_task_struct(p);
- unlock_cpu_hotplug();
+ mutex_unlock(&sched_hotcpu_mutex);
return retval;
}
struct task_struct *p;
int retval;
- lock_cpu_hotplug();
+ mutex_lock(&sched_hotcpu_mutex);
read_lock(&tasklist_lock);
retval = -ESRCH;
out_unlock:
read_unlock(&tasklist_lock);
- unlock_cpu_hotplug();
+ mutex_unlock(&sched_hotcpu_mutex);
if (retval)
return retval;
/**
* 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.
+ * This function yields the current CPU to other tasks. If there are no
+ * other threads running on this CPU then this function will return.
*/
asmlinkage long sys_sched_yield(void)
{
struct rq *rq = this_rq_lock();
- struct prio_array *array = current->array, *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) {
+ if (unlikely(rq->nr_running == 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);
+ else
+ current->sched_class->yield_task(rq, current);
/*
* Since we are going to call schedule() anyway, there's
BUG_ON(!in_softirq());
if (need_resched() && system_state == SYSTEM_RUNNING) {
- raw_local_irq_disable();
- _local_bh_enable();
- raw_local_irq_enable();
+ local_bh_enable();
__cond_resched();
local_bh_disable();
return 1;
break;
case SCHED_NORMAL:
case SCHED_BATCH:
+ case SCHED_IDLE:
ret = 0;
break;
}
break;
case SCHED_NORMAL:
case SCHED_BATCH:
+ case SCHED_IDLE:
ret = 0;
}
return ret;
goto out_unlock;
jiffies_to_timespec(p->policy == SCHED_FIFO ?
- 0 : task_timeslice(p), &t);
+ 0 : static_prio_timeslice(p->static_prio), &t);
read_unlock(&tasklist_lock);
retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
out_nounlock:
state = p->state ? __ffs(p->state) + 1 : 0;
printk("%-13.13s %c", p->comm,
state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
-#if (BITS_PER_LONG == 32)
+#if BITS_PER_LONG == 32
if (state == TASK_RUNNING)
- printk(" running ");
+ printk(" running ");
else
- printk(" %08lX ", thread_saved_pc(p));
+ printk(" %08lx ", thread_saved_pc(p));
#else
if (state == TASK_RUNNING)
- printk(" running task ");
+ printk(" running task ");
else
printk(" %016lx ", thread_saved_pc(p));
#endif
free = (unsigned long)n - (unsigned long)end_of_stack(p);
}
#endif
- printk("%5lu %5d %6d", free, p->pid, p->parent->pid);
- if (!p->mm)
- printk(" (L-TLB)\n");
- else
- printk(" (NOTLB)\n");
+ printk("%5lu %5d %6d\n", free, p->pid, p->parent->pid);
if (state != TASK_RUNNING)
show_stack(p, NULL);
{
struct task_struct *g, *p;
-#if (BITS_PER_LONG == 32)
- printk("\n"
- " free sibling\n");
- printk(" task PC stack pid father child younger older\n");
+#if BITS_PER_LONG == 32
+ printk(KERN_INFO
+ " task PC stack pid father\n");
#else
- printk("\n"
- " free sibling\n");
- printk(" task PC stack pid father child younger older\n");
+ printk(KERN_INFO
+ " task PC stack pid father\n");
#endif
read_lock(&tasklist_lock);
do_each_thread(g, p) {
touch_all_softlockup_watchdogs();
+#ifdef CONFIG_SCHED_DEBUG
+ sysrq_sched_debug_show();
+#endif
read_unlock(&tasklist_lock);
/*
* Only show locks if all tasks are dumped:
debug_show_all_locks();
}
+void __cpuinit init_idle_bootup_task(struct task_struct *idle)
+{
+ idle->sched_class = &idle_sched_class;
+}
+
/**
* init_idle - set up an idle thread for a given CPU
* @idle: task in question
struct rq *rq = cpu_rq(cpu);
unsigned long flags;
- idle->timestamp = sched_clock();
- idle->sleep_avg = 0;
- idle->array = NULL;
+ __sched_fork(idle);
+ idle->se.exec_start = sched_clock();
+
idle->prio = idle->normal_prio = MAX_PRIO;
- idle->state = TASK_RUNNING;
idle->cpus_allowed = cpumask_of_cpu(cpu);
- set_task_cpu(idle, cpu);
+ __set_task_cpu(idle, cpu);
spin_lock_irqsave(&rq->lock, flags);
rq->curr = rq->idle = idle;
#else
task_thread_info(idle)->preempt_count = 0;
#endif
+ /*
+ * The idle tasks have their own, simple scheduling class:
+ */
+ idle->sched_class = &idle_sched_class;
}
/*
*/
cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
+/*
+ * Increase the granularity value when there are more CPUs,
+ * because with more CPUs the 'effective latency' as visible
+ * to users decreases. But the relationship is not linear,
+ * so pick a second-best guess by going with the log2 of the
+ * number of CPUs.
+ *
+ * This idea comes from the SD scheduler of Con Kolivas:
+ */
+static inline void sched_init_granularity(void)
+{
+ unsigned int factor = 1 + ilog2(num_online_cpus());
+ const unsigned long gran_limit = 100000000;
+
+ sysctl_sched_granularity *= factor;
+ if (sysctl_sched_granularity > gran_limit)
+ sysctl_sched_granularity = gran_limit;
+
+ sysctl_sched_runtime_limit = sysctl_sched_granularity * 4;
+ sysctl_sched_wakeup_granularity = sysctl_sched_granularity / 2;
+}
+
#ifdef CONFIG_SMP
/*
* This is how migration works:
static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
{
struct rq *rq_dest, *rq_src;
- int ret = 0;
+ int ret = 0, on_rq;
if (unlikely(cpu_is_offline(dest_cpu)))
return ret;
if (!cpu_isset(dest_cpu, p->cpus_allowed))
goto out;
+ on_rq = p->se.on_rq;
+ if (on_rq)
+ deactivate_task(rq_src, p, 0);
set_task_cpu(p, dest_cpu);
- if (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->most_recent_timestamp
- + rq_dest->most_recent_timestamp;
- deactivate_task(p, rq_src);
- __activate_task(p, rq_dest);
- if (TASK_PREEMPTS_CURR(p, rq_dest))
- resched_task(rq_dest->curr);
+ if (on_rq) {
+ activate_task(rq_dest, p, 0);
+ check_preempt_curr(rq_dest, p);
}
ret = 1;
out:
struct migration_req *req;
struct list_head *head;
- try_to_freeze();
-
spin_lock_irq(&rq->lock);
if (cpu_is_offline(cpu)) {
write_unlock_irq(&tasklist_lock);
}
-/* Schedules idle task to be the next runnable task on current CPU.
+/*
+ * 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 the runqueue. Used by CPU offline code.
*/
*/
spin_lock_irqsave(&rq->lock, flags);
- __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1);
+ __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
/* Add idle task to the _front_ of its priority queue: */
- __activate_idle_task(p, rq);
+ activate_idle_task(p, rq);
spin_unlock_irqrestore(&rq->lock, flags);
}
static void migrate_dead_tasks(unsigned int dead_cpu)
{
struct rq *rq = cpu_rq(dead_cpu);
- unsigned int arr, i;
+ struct task_struct *next;
- 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,
- struct task_struct, run_list));
- }
+ for ( ; ; ) {
+ if (!rq->nr_running)
+ break;
+ next = pick_next_task(rq, rq->curr, rq_clock(rq));
+ if (!next)
+ break;
+ migrate_dead(dead_cpu, next);
}
}
#endif /* CONFIG_HOTPLUG_CPU */
struct rq *rq;
switch (action) {
+ case CPU_LOCK_ACQUIRE:
+ mutex_lock(&sched_hotcpu_mutex);
+ break;
+
case CPU_UP_PREPARE:
- p = kthread_create(migration_thread, hcpu, "migration/%d",cpu);
+ case CPU_UP_PREPARE_FROZEN:
+ 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);
+ __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
task_rq_unlock(rq, &flags);
cpu_rq(cpu)->migration_thread = p;
break;
case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
/* Strictly unneccessary, as first user will wake it. */
wake_up_process(cpu_rq(cpu)->migration_thread);
break;
#ifdef CONFIG_HOTPLUG_CPU
case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
if (!cpu_rq(cpu)->migration_thread)
break;
/* Unbind it from offline cpu so it can run. Fall thru. */
break;
case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
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);
+ deactivate_task(rq, rq->idle, 0);
rq->idle->static_prio = MAX_PRIO;
- __setscheduler(rq->idle, SCHED_NORMAL, 0);
+ __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
+ rq->idle->sched_class = &idle_sched_class;
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
+ * they didn't take sched_hotcpu_mutex. Just wake up
* the requestors. */
spin_lock_irq(&rq->lock);
while (!list_empty(&rq->migration_queue)) {
spin_unlock_irq(&rq->lock);
break;
#endif
+ case CPU_LOCK_RELEASE:
+ mutex_unlock(&sched_hotcpu_mutex);
+ break;
}
return NOTIFY_OK;
}
break;
}
- if (!group->cpu_power) {
+ if (!group->__cpu_power) {
printk("\n");
printk(KERN_ERR "ERROR: domain->cpu_power not "
"set\n");
continue;
sg->cpumask = CPU_MASK_NONE;
- sg->cpu_power = 0;
+ sg->__cpu_power = 0;
for_each_cpu_mask(j, span) {
if (group_fn(j, cpu_map, NULL) != group)
#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 1
-#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 ] =
-/*
- * Architectures may override the migration cost and thus avoid
- * boot-time calibration. Unit is nanoseconds. Mostly useful for
- * virtualized hardware:
- */
-#ifdef CONFIG_DEFAULT_MIGRATION_COST
- CONFIG_DEFAULT_MIGRATION_COST
-#else
- -1LL
-#endif
-};
-
-/*
- * 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);
- unsigned long chunk1 = size / 3;
- unsigned long 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 10% steps:
- */
- size = size * 10 / 9;
- }
-
- 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
- );
- if (system_state == SYSTEM_BOOTING && num_online_cpus() > 1) {
- 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
/**
continue;
}
- sg->cpu_power += sd->groups->cpu_power;
+ sg_inc_cpu_power(sg, sd->groups->__cpu_power);
}
sg = sg->next;
if (sg != group_head)
child = sd->child;
+ sd->groups->__cpu_power = 0;
+
/*
* For perf policy, if the groups in child domain share resources
* (for example cores sharing some portions of the cache hierarchy
if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
(child->flags &
(SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
- sd->groups->cpu_power = SCHED_LOAD_SCALE;
+ sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
return;
}
- sd->groups->cpu_power = 0;
-
/*
* add cpu_power of each child group to this groups cpu_power
*/
group = child->groups;
do {
- sd->groups->cpu_power += group->cpu_power;
+ sg_inc_cpu_power(sd->groups, group->__cpu_power);
group = group->next;
} while (group != child->groups);
}
static int build_sched_domains(const cpumask_t *cpu_map)
{
int i;
- struct sched_domain *sd;
#ifdef CONFIG_NUMA
struct sched_group **sched_group_nodes = NULL;
int sd_allnodes = 0;
/*
* Allocate the per-node list of sched groups
*/
- sched_group_nodes = kzalloc(sizeof(struct sched_group*)*MAX_NUMNODES,
+ sched_group_nodes = kzalloc(sizeof(struct sched_group *)*MAX_NUMNODES,
GFP_KERNEL);
if (!sched_group_nodes) {
printk(KERN_WARNING "Can not alloc sched group node list\n");
cpus_and(nodemask, nodemask, *cpu_map);
#ifdef CONFIG_NUMA
- if (cpus_weight(*cpu_map)
- > SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) {
+ if (cpus_weight(*cpu_map) >
+ SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) {
sd = &per_cpu(allnodes_domains, i);
*sd = SD_ALLNODES_INIT;
sd->span = *cpu_map;
if (i != first_cpu(this_sibling_map))
continue;
- init_sched_build_groups(this_sibling_map, cpu_map, &cpu_to_cpu_group);
+ init_sched_build_groups(this_sibling_map, cpu_map,
+ &cpu_to_cpu_group);
}
#endif
cpus_and(this_core_map, this_core_map, *cpu_map);
if (i != first_cpu(this_core_map))
continue;
- init_sched_build_groups(this_core_map, cpu_map, &cpu_to_core_group);
+ init_sched_build_groups(this_core_map, cpu_map,
+ &cpu_to_core_group);
}
#endif
-
/* Set up physical groups */
for (i = 0; i < MAX_NUMNODES; i++) {
cpumask_t nodemask = node_to_cpumask(i);
#ifdef CONFIG_NUMA
/* Set up node groups */
if (sd_allnodes)
- init_sched_build_groups(*cpu_map, cpu_map, &cpu_to_allnodes_group);
+ init_sched_build_groups(*cpu_map, cpu_map,
+ &cpu_to_allnodes_group);
for (i = 0; i < MAX_NUMNODES; i++) {
/* Set up node groups */
sched_group_nodes[i] = sg;
for_each_cpu_mask(j, nodemask) {
struct sched_domain *sd;
+
sd = &per_cpu(node_domains, j);
sd->groups = sg;
}
- sg->cpu_power = 0;
+ sg->__cpu_power = 0;
sg->cpumask = nodemask;
sg->next = sg;
cpus_or(covered, covered, nodemask);
"Can not alloc domain group for node %d\n", j);
goto error;
}
- sg->cpu_power = 0;
+ sg->__cpu_power = 0;
sg->cpumask = tmp;
sg->next = prev->next;
cpus_or(covered, covered, tmp);
/* Calculate CPU power for physical packages and nodes */
#ifdef CONFIG_SCHED_SMT
for_each_cpu_mask(i, *cpu_map) {
- sd = &per_cpu(cpu_domains, i);
+ struct sched_domain *sd = &per_cpu(cpu_domains, i);
+
init_sched_groups_power(i, sd);
}
#endif
#ifdef CONFIG_SCHED_MC
for_each_cpu_mask(i, *cpu_map) {
- sd = &per_cpu(core_domains, i);
+ struct sched_domain *sd = &per_cpu(core_domains, i);
+
init_sched_groups_power(i, sd);
}
#endif
for_each_cpu_mask(i, *cpu_map) {
- sd = &per_cpu(phys_domains, i);
+ struct sched_domain *sd = &per_cpu(phys_domains, i);
+
init_sched_groups_power(i, sd);
}
#endif
cpu_attach_domain(sd, i);
}
- /*
- * Tune cache-hot values:
- */
- calibrate_migration_costs(cpu_map);
return 0;
{
int err;
- lock_cpu_hotplug();
+ mutex_lock(&sched_hotcpu_mutex);
detach_destroy_domains(&cpu_online_map);
err = arch_init_sched_domains(&cpu_online_map);
- unlock_cpu_hotplug();
+ mutex_unlock(&sched_hotcpu_mutex);
return err;
}
{
switch (action) {
case CPU_UP_PREPARE:
+ case CPU_UP_PREPARE_FROZEN:
case CPU_DOWN_PREPARE:
+ case CPU_DOWN_PREPARE_FROZEN:
detach_destroy_domains(&cpu_online_map);
return NOTIFY_OK;
case CPU_UP_CANCELED:
+ case CPU_UP_CANCELED_FROZEN:
case CPU_DOWN_FAILED:
+ case CPU_DOWN_FAILED_FROZEN:
case CPU_ONLINE:
+ case CPU_ONLINE_FROZEN:
case CPU_DEAD:
+ case CPU_DEAD_FROZEN:
/*
* Fall through and re-initialise the domains.
*/
{
cpumask_t non_isolated_cpus;
- lock_cpu_hotplug();
+ mutex_lock(&sched_hotcpu_mutex);
arch_init_sched_domains(&cpu_online_map);
cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
if (cpus_empty(non_isolated_cpus))
cpu_set(smp_processor_id(), non_isolated_cpus);
- unlock_cpu_hotplug();
+ mutex_unlock(&sched_hotcpu_mutex);
/* XXX: Theoretical race here - CPU may be hotplugged now */
hotcpu_notifier(update_sched_domains, 0);
/* Move init over to a non-isolated CPU */
if (set_cpus_allowed(current, non_isolated_cpus) < 0)
BUG();
+ sched_init_granularity();
}
#else
void __init sched_init_smp(void)
{
+ sched_init_granularity();
}
#endif /* CONFIG_SMP */
&& addr < (unsigned long)__sched_text_end);
}
+static inline void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
+{
+ cfs_rq->tasks_timeline = RB_ROOT;
+ cfs_rq->fair_clock = 1;
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ cfs_rq->rq = rq;
+#endif
+}
+
void __init sched_init(void)
{
- int i, j, k;
+ u64 now = sched_clock();
int highest_cpu = 0;
+ int i, j;
+
+ /*
+ * Link up the scheduling class hierarchy:
+ */
+ rt_sched_class.next = &fair_sched_class;
+ fair_sched_class.next = &idle_sched_class;
+ idle_sched_class.next = NULL;
for_each_possible_cpu(i) {
- struct prio_array *array;
+ struct rt_prio_array *array;
struct rq *rq;
rq = cpu_rq(i);
spin_lock_init(&rq->lock);
lockdep_set_class(&rq->lock, &rq->rq_lock_key);
rq->nr_running = 0;
- rq->active = rq->arrays;
- rq->expired = rq->arrays + 1;
- rq->best_expired_prio = MAX_PRIO;
+ rq->clock = 1;
+ init_cfs_rq(&rq->cfs, rq);
+#ifdef CONFIG_FAIR_GROUP_SCHED
+ INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
+ list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
+#endif
+ rq->ls.load_update_last = now;
+ rq->ls.load_update_start = now;
+ for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
+ rq->cpu_load[j] = 0;
#ifdef CONFIG_SMP
rq->sd = NULL;
- for (j = 1; j < 3; j++)
- rq->cpu_load[j] = 0;
rq->active_balance = 0;
+ rq->next_balance = jiffies;
rq->push_cpu = 0;
rq->cpu = i;
rq->migration_thread = NULL;
#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);
+ array = &rq->rt.active;
+ for (j = 0; j < MAX_RT_PRIO; j++) {
+ INIT_LIST_HEAD(array->queue + j);
+ __clear_bit(j, array->bitmap);
}
highest_cpu = i;
+ /* delimiter for bitsearch: */
+ __set_bit(MAX_RT_PRIO, array->bitmap);
}
set_load_weight(&init_task);
* when this runqueue becomes "idle".
*/
init_idle(current, smp_processor_id());
+ /*
+ * During early bootup we pretend to be a normal task:
+ */
+ current->sched_class = &fair_sched_class;
}
#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
#ifdef CONFIG_MAGIC_SYSRQ
void normalize_rt_tasks(void)
{
- struct prio_array *array;
- struct task_struct *p;
+ struct task_struct *g, *p;
unsigned long flags;
struct rq *rq;
+ int on_rq;
read_lock_irq(&tasklist_lock);
- for_each_process(p) {
- if (!rt_task(p))
+ do_each_thread(g, p) {
+ p->se.fair_key = 0;
+ p->se.wait_runtime = 0;
+ p->se.wait_start_fair = 0;
+ p->se.wait_start = 0;
+ p->se.exec_start = 0;
+ p->se.sleep_start = 0;
+ p->se.sleep_start_fair = 0;
+ p->se.block_start = 0;
+ task_rq(p)->cfs.fair_clock = 0;
+ task_rq(p)->clock = 0;
+
+ if (!rt_task(p)) {
+ /*
+ * Renice negative nice level userspace
+ * tasks back to 0:
+ */
+ if (TASK_NICE(p) < 0 && p->mm)
+ set_user_nice(p, 0);
continue;
+ }
spin_lock_irqsave(&p->pi_lock, flags);
rq = __task_rq_lock(p);
+#ifdef CONFIG_SMP
+ /*
+ * Do not touch the migration thread:
+ */
+ if (p == rq->migration_thread)
+ goto out_unlock;
+#endif
- array = p->array;
- if (array)
- deactivate_task(p, task_rq(p));
- __setscheduler(p, SCHED_NORMAL, 0);
- if (array) {
- __activate_task(p, task_rq(p));
+ on_rq = p->se.on_rq;
+ if (on_rq)
+ deactivate_task(task_rq(p), p, 0);
+ __setscheduler(rq, p, SCHED_NORMAL, 0);
+ if (on_rq) {
+ activate_task(task_rq(p), p, 0);
resched_task(rq->curr);
}
-
+#ifdef CONFIG_SMP
+ out_unlock:
+#endif
__task_rq_unlock(rq);
spin_unlock_irqrestore(&p->pi_lock, flags);
- }
+ } while_each_thread(g, p);
+
read_unlock_irq(&tasklist_lock);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff