* 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/percpu.h>
#include <linux/kthread.h>
#include <linux/seq_file.h>
+#include <linux/sysctl.h>
#include <linux/syscalls.h>
#include <linux/times.h>
#include <linux/tsacct_kern.h>
#include <linux/kprobes.h>
#include <linux/delayacct.h>
#include <linux/reciprocal_div.h>
+#include <linux/unistd.h>
+#include <linux/pagemap.h>
#include <asm/tlb.h>
-#include <asm/unistd.h>
/*
* Scheduler clock - returns current time in nanosec units.
*/
#define MIN_TIMESLICE max(5 * HZ / 1000, 1)
#define DEF_TIMESLICE (100 * HZ / 1000)
-#define ON_RUNQUEUE_WEIGHT 30
-#define CHILD_PENALTY 95
-#define PARENT_PENALTY 100
-#define EXIT_WEIGHT 3
-#define PRIO_BONUS_RATIO 25
-#define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100)
-#define INTERACTIVE_DELTA 2
-#define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS)
-#define STARVATION_LIMIT (MAX_SLEEP_AVG)
-#define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG))
-
-/*
- * If a task is 'interactive' then we reinsert it in the active
- * array after it has expired its current timeslice. (it will not
- * continue to run immediately, it will still roundrobin with
- * other interactive tasks.)
- *
- * This part scales the interactivity limit depending on niceness.
- *
- * We scale it linearly, offset by the INTERACTIVE_DELTA delta.
- * Here are a few examples of different nice levels:
- *
- * TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0]
- * TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0]
- * TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0]
- * TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0]
- * TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0]
- *
- * (the X axis represents the possible -5 ... 0 ... +5 dynamic
- * priority range a task can explore, a value of '1' means the
- * task is rated interactive.)
- *
- * Ie. nice +19 tasks can never get 'interactive' enough to be
- * reinserted into the active array. And only heavily CPU-hog nice -20
- * tasks will be expired. Default nice 0 tasks are somewhere between,
- * it takes some effort for them to get interactive, but it's not
- * too hard.
- */
-
-#define CURRENT_BONUS(p) \
- (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \
- MAX_SLEEP_AVG)
-
-#define GRANULARITY (10 * HZ / 1000 ? : 1)
-
-#ifdef CONFIG_SMP
-#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \
- (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \
- num_online_cpus())
-#else
-#define TIMESLICE_GRANULARITY(p) (GRANULARITY * \
- (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)))
-#endif
-
-#define SCALE(v1,v1_max,v2_max) \
- (v1) * (v2_max) / (v1_max)
-
-#define DELTA(p) \
- (SCALE(TASK_NICE(p) + 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 unsigned int static_prio_timeslice(int static_prio)
-{
- if (static_prio < NICE_TO_PRIO(0))
- return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio);
- else
- return SCALE_PRIO(DEF_TIMESLICE, static_prio);
-}
#ifdef CONFIG_SMP
/*
}
#endif
+#define SCALE_PRIO(x, prio) \
+ max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE)
+
/*
- * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ]
+ * static_prio_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 unsigned int task_timeslice(struct task_struct *p)
+static unsigned int static_prio_timeslice(int static_prio)
{
- return static_prio_timeslice(p->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);
}
static inline int rt_policy(int policy)
};
/*
- * The prio-array type of the old scheduler:
- */
-struct prio_array {
- unsigned int nr_active;
- DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */
- struct list_head queue[MAX_PRIO];
-};
-
-/*
* This is the main, per-CPU runqueue data structure.
*
* Locking rule: those places that want to lock multiple runqueues
* remote CPUs use both these fields when doing load calculation.
*/
unsigned long nr_running;
- unsigned long raw_weighted_load;
#define CPU_LOAD_IDX_MAX 5
unsigned long cpu_load[CPU_LOAD_IDX_MAX];
unsigned char idle_at_tick;
*/
unsigned long nr_uninterruptible;
- unsigned long expired_timestamp;
- 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;
+ u64 idle_clock;
+ unsigned int clock_deep_idle_events;
+ u64 tick_timestamp;
atomic_t nr_iowait;
struct lock_class_key rq_lock_key;
};
-static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp;
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
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)
{
#ifdef CONFIG_SMP
}
/*
- * Per-runqueue clock, as finegrained as the platform can give us:
+ * Update the per-runqueue clock, as finegrained as the platform can give
+ * us, but without assuming monotonicity, etc.:
*/
-static unsigned long long __rq_clock(struct rq *rq)
+static void __update_rq_clock(struct rq *rq)
{
u64 prev_raw = rq->prev_clock_raw;
u64 now = sched_clock();
s64 delta = now - prev_raw;
u64 clock = rq->clock;
+#ifdef CONFIG_SCHED_DEBUG
+ WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
+#endif
/*
* Protect against sched_clock() occasionally going backwards:
*/
/*
* Catch too large forward jumps too:
*/
- if (unlikely(delta > 2*TICK_NSEC)) {
- clock++;
+ if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) {
+ if (clock < rq->tick_timestamp + TICK_NSEC)
+ clock = rq->tick_timestamp + TICK_NSEC;
+ else
+ clock++;
rq->clock_overflows++;
} else {
if (unlikely(delta > rq->clock_max_delta))
rq->prev_clock_raw = now;
rq->clock = clock;
-
- return clock;
}
-static inline unsigned long long rq_clock(struct rq *rq)
+static void update_rq_clock(struct rq *rq)
{
- int this_cpu = smp_processor_id();
-
- if (this_cpu == cpu_of(rq))
- return __rq_clock(rq);
-
- return rq->clock;
+ if (likely(smp_processor_id() == cpu_of(rq)))
+ __update_rq_clock(rq);
}
/*
#define task_rq(p) cpu_rq(task_cpu(p))
#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
+/*
+ * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
+ * clock constructed from sched_clock():
+ */
+unsigned long long cpu_clock(int cpu)
+{
+ unsigned long long now;
+ unsigned long flags;
+ struct rq *rq;
+
+ local_irq_save(flags);
+ rq = cpu_rq(cpu);
+ update_rq_clock(rq);
+ now = rq->clock;
+ local_irq_restore(flags);
+
+ return now;
+}
+
#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)
}
/*
+ * We are going deep-idle (irqs are disabled):
+ */
+void sched_clock_idle_sleep_event(void)
+{
+ struct rq *rq = cpu_rq(smp_processor_id());
+
+ spin_lock(&rq->lock);
+ __update_rq_clock(rq);
+ spin_unlock(&rq->lock);
+ rq->clock_deep_idle_events++;
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
+
+/*
+ * We just idled delta nanoseconds (called with irqs disabled):
+ */
+void sched_clock_idle_wakeup_event(u64 delta_ns)
+{
+ struct rq *rq = cpu_rq(smp_processor_id());
+ u64 now = sched_clock();
+
+ rq->idle_clock += delta_ns;
+ /*
+ * Override the previous timestamp and ignore all
+ * sched_clock() deltas that occured while we idled,
+ * and use the PM-provided delta_ns to advance the
+ * rq clock:
+ */
+ spin_lock(&rq->lock);
+ rq->prev_clock_raw = now;
+ rq->clock += delta_ns;
+ spin_unlock(&rq->lock);
+}
+EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
+
+/*
* resched_task - mark a task 'to be rescheduled now'.
*
* On UP this means the setting of the need_resched flag, on SMP it
}
#endif
-#include "sched_stats.h"
-
static u64 div64_likely32(u64 divident, unsigned long divisor)
{
#if BITS_PER_LONG == 32
#define WMULT_SHIFT 32
-static inline unsigned long
+/*
+ * Shift right and round:
+ */
+#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
+
+static unsigned long
calc_delta_mine(unsigned long delta_exec, unsigned long weight,
struct load_weight *lw)
{
u64 tmp;
if (unlikely(!lw->inv_weight))
- lw->inv_weight = WMULT_CONST / lw->weight;
+ lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1;
tmp = (u64)delta_exec * weight;
/*
* Check whether we'd overflow the 64-bit multiplication:
*/
- if (unlikely(tmp > WMULT_CONST)) {
- tmp = ((tmp >> WMULT_SHIFT/2) * lw->inv_weight)
- >> (WMULT_SHIFT/2);
- } else {
- tmp = (tmp * lw->inv_weight) >> WMULT_SHIFT;
- }
+ if (unlikely(tmp > WMULT_CONST))
+ tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
+ WMULT_SHIFT/2);
+ else
+ tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
- return (unsigned long)min(tmp, (u64)sysctl_sched_runtime_limit);
+ return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
}
static inline unsigned long
lw->inv_weight = 0;
}
+/*
+ * To aid in avoiding the subversion of "niceness" due to uneven distribution
+ * of tasks with abnormal "nice" values across CPUs the contribution that
+ * each task makes to its run queue's load is weighted according to its
+ * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
+ * scaled version of the new time slice allocation that they receive on time
+ * slice expiry etc.
+ */
+
+#define WEIGHT_IDLEPRIO 2
+#define WMULT_IDLEPRIO (1 << 31)
+
+/*
+ * Nice levels are multiplicative, with a gentle 10% change for every
+ * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
+ * nice 1, it will get ~10% less CPU time than another CPU-bound task
+ * that remained on nice 0.
+ *
+ * The "10% effect" is relative and cumulative: from _any_ nice level,
+ * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
+ * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
+ * If a task goes up by ~10% and another task goes down by ~10% then
+ * the relative distance between them is ~25%.)
+ */
+static const int prio_to_weight[40] = {
+ /* -20 */ 88761, 71755, 56483, 46273, 36291,
+ /* -15 */ 29154, 23254, 18705, 14949, 11916,
+ /* -10 */ 9548, 7620, 6100, 4904, 3906,
+ /* -5 */ 3121, 2501, 1991, 1586, 1277,
+ /* 0 */ 1024, 820, 655, 526, 423,
+ /* 5 */ 335, 272, 215, 172, 137,
+ /* 10 */ 110, 87, 70, 56, 45,
+ /* 15 */ 36, 29, 23, 18, 15,
+};
+
+/*
+ * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
+ *
+ * In cases where the weight does not change often, we can use the
+ * precalculated inverse to speed up arithmetics by turning divisions
+ * into multiplications:
+ */
+static const u32 prio_to_wmult[40] = {
+ /* -20 */ 48388, 59856, 76040, 92818, 118348,
+ /* -15 */ 147320, 184698, 229616, 287308, 360437,
+ /* -10 */ 449829, 563644, 704093, 875809, 1099582,
+ /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
+ /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
+ /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
+ /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
+ /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
+};
+
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
+
+/*
+ * runqueue iterator, to support SMP load-balancing between different
+ * scheduling classes, without having to expose their internal data
+ * structures to the load-balancing proper:
+ */
+struct rq_iterator {
+ void *arg;
+ struct task_struct *(*start)(void *);
+ struct task_struct *(*next)(void *);
+};
+
+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, 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 __update_curr_load(struct rq *rq, struct load_stat *ls)
{
if (rq->curr != rq->idle && ls->load.weight) {
* This function is called /before/ updating rq->ls.load
* and when switching tasks.
*/
-static void update_curr_load(struct rq *rq, u64 now)
+static void update_curr_load(struct rq *rq)
{
struct load_stat *ls = &rq->ls;
u64 start;
start = ls->load_update_start;
- ls->load_update_start = now;
- ls->delta_stat += now - start;
+ ls->load_update_start = rq->clock;
+ ls->delta_stat += rq->clock - start;
/*
* Stagger updates to ls->delta_fair. Very frequent updates
* can be expensive.
__update_curr_load(rq, ls);
}
-/*
- * To aid in avoiding the subversion of "niceness" due to uneven distribution
- * of tasks with abnormal "nice" values across CPUs the contribution that
- * each task makes to its run queue's load is weighted according to its
- * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
- * scaled version of the new time slice allocation that they receive on time
- * slice expiry etc.
- */
-
-/*
- * Assume: static_prio_timeslice(NICE_TO_PRIO(0)) == DEF_TIMESLICE
- * If static_prio_timeslice() is ever changed to break this assumption then
- * this code will need modification
- */
-#define TIME_SLICE_NICE_ZERO DEF_TIMESLICE
-#define LOAD_WEIGHT(lp) \
- (((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO)
-#define PRIO_TO_LOAD_WEIGHT(prio) \
- LOAD_WEIGHT(static_prio_timeslice(prio))
-#define RTPRIO_TO_LOAD_WEIGHT(rp) \
- (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + LOAD_WEIGHT(rp))
-
-static inline void
-inc_raw_weighted_load(struct rq *rq, const struct task_struct *p)
+static inline void inc_load(struct rq *rq, const struct task_struct *p)
{
- rq->raw_weighted_load += p->load_weight;
+ update_curr_load(rq);
+ 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)
+static inline void dec_load(struct rq *rq, const struct task_struct *p)
{
- rq->raw_weighted_load -= p->load_weight;
+ update_curr_load(rq);
+ update_load_sub(&rq->ls.load, p->se.load.weight);
}
-static inline void inc_nr_running(struct task_struct *p, struct rq *rq)
+static void inc_nr_running(struct task_struct *p, struct rq *rq)
{
rq->nr_running++;
- inc_raw_weighted_load(rq, p);
+ inc_load(rq, p);
}
-static inline void dec_nr_running(struct task_struct *p, struct rq *rq)
+static void dec_nr_running(struct task_struct *p, struct rq *rq)
{
rq->nr_running--;
- dec_raw_weighted_load(rq, p);
+ dec_load(rq, p);
}
static void set_load_weight(struct task_struct *p)
{
+ p->se.wait_runtime = 0;
+
if (task_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);
-}
+ p->se.load.weight = prio_to_weight[0] * 2;
+ p->se.load.inv_weight = prio_to_wmult[0] >> 1;
+ return;
+ }
-/*
- * Adding/removing a task to/from a priority array:
- */
-static void dequeue_task(struct task_struct *p, struct prio_array *array)
-{
- array->nr_active--;
- list_del(&p->run_list);
- if (list_empty(array->queue + p->prio))
- __clear_bit(p->prio, array->bitmap);
-}
+ /*
+ * 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;
+ }
-static void enqueue_task(struct task_struct *p, struct prio_array *array)
-{
- sched_info_queued(p);
- list_add_tail(&p->run_list, array->queue + p->prio);
- __set_bit(p->prio, array->bitmap);
- array->nr_active++;
- p->array = array;
+ 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];
}
-/*
- * 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 enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
{
- list_move_tail(&p->run_list, array->queue + p->prio);
+ sched_info_queued(p);
+ p->sched_class->enqueue_task(rq, p, wakeup);
+ p->se.on_rq = 1;
}
-static inline void
-enqueue_task_head(struct task_struct *p, struct prio_array *array)
+static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
{
- list_add(&p->run_list, array->queue + p->prio);
- __set_bit(p->prio, array->bitmap);
- array->nr_active++;
- p->array = array;
+ p->sched_class->dequeue_task(rq, p, sleep);
+ p->se.on_rq = 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.
- *
- * We use 25% of the full 0...39 priority range so that:
- *
- * 1) nice +19 interactive tasks do not preempt nice 0 CPU hogs.
- * 2) nice -20 CPU hogs do not get preempted by nice 0 tasks.
- *
- * Both properties are important to certain workloads.
+ * __normal_prio - return the priority that is based on the static prio
*/
-
static inline int __normal_prio(struct task_struct *p)
{
- int bonus, prio;
-
- bonus = 0;
-
- 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;
+ return p->static_prio;
}
/*
}
/*
- * __activate_task - move a task to the runqueue.
+ * activate_task - move a task to the runqueue.
*/
-static void __activate_task(struct task_struct *p, struct rq *rq)
+static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
{
- struct prio_array *target = rq->active;
-
- if (batch_task(p))
- target = rq->expired;
- enqueue_task(p, target);
- inc_nr_running(p, rq);
-}
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ rq->nr_uninterruptible--;
-/*
- * __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);
+ enqueue_task(rq, p, wakeup);
inc_nr_running(p, rq);
}
/*
- * Recalculate p->normal_prio and p->prio after having slept,
- * updating the sleep-average too:
+ * activate_idle_task - move idle task to the _front_ of runqueue.
*/
-static int recalc_task_prio(struct task_struct *p, unsigned long long now)
+static inline void activate_idle_task(struct task_struct *p, struct rq *rq)
{
- return effective_prio(p);
-}
-
-/*
- * activate_task - move a task to the runqueue and do priority recalculation
- *
- * Update all the scheduling statistics stuff. (sleep average
- * calculation, priority modifiers, etc.)
- */
-static void activate_task(struct task_struct *p, struct rq *rq, int local)
-{
- unsigned long long now;
-
- if (rt_task(p))
- goto out;
+ update_rq_clock(rq);
- 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
-
- /*
- * 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);
- }
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ rq->nr_uninterruptible--;
- p->prio = recalc_task_prio(p, now);
- p->timestamp = now;
-out:
- __activate_task(p, rq);
+ enqueue_task(rq, p, 0);
+ inc_nr_running(p, rq);
}
/*
* deactivate_task - remove a task from the runqueue.
*/
-static void deactivate_task(struct task_struct *p, struct rq *rq)
+static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
{
+ if (p->state == TASK_UNINTERRUPTIBLE)
+ rq->nr_uninterruptible++;
+
+ dequeue_task(rq, p, sleep);
dec_nr_running(p, rq);
- dequeue_task(p, p->array);
- p->array = NULL;
}
/**
/* 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 cpu)
+void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
{
- task_thread_info(p)->cpu = 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_fair)
+ p->se.wait_start_fair -= fair_clock_offset;
+ if (p->se.sleep_start_fair)
+ p->se.sleep_start_fair -= fair_clock_offset;
+
+#ifdef CONFIG_SCHEDSTATS
+ if (p->se.wait_start)
+ p->se.wait_start -= clock_offset;
+ if (p->se.sleep_start)
+ p->se.sleep_start -= clock_offset;
+ if (p->se.block_start)
+ p->se.block_start -= clock_offset;
+#endif
+
+ __set_task_cpu(p, new_cpu);
}
struct migration_req {
* 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;
- struct prio_array *array;
- int running;
repeat:
/*
*/
rq = task_rq_lock(p, &flags);
running = task_running(rq, p);
- array = p->array;
+ on_rq = p->se.on_rq;
task_rq_unlock(rq, &flags);
/*
* running right now), it's preempted, and we should
* yield - it could be a while.
*/
- if (unlikely(array)) {
+ if (unlikely(on_rq)) {
yield();
goto repeat;
}
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;
}
/*
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)
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--;
-
- activate_task(p, rq, cpu == this_cpu);
+ update_rq_clock(rq);
+ 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.
+ *
+ * __sched_fork() is basic setup used by init_idle() too:
*/
-void fastcall sched_fork(struct task_struct *p, int clone_flags)
+static void __sched_fork(struct task_struct *p)
{
- int cpu = get_cpu();
+ p->se.wait_start_fair = 0;
+ p->se.exec_start = 0;
+ p->se.sum_exec_runtime = 0;
+ p->se.prev_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.sleep_start_fair = 0;
-#ifdef CONFIG_SMP
- cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
+#ifdef CONFIG_SCHEDSTATS
+ p->se.wait_start = 0;
+ p->se.sum_wait_runtime = 0;
+ p->se.sum_sleep_runtime = 0;
+ p->se.sleep_start = 0;
+ p->se.block_start = 0;
+ p->se.sleep_max = 0;
+ p->se.block_max = 0;
+ p->se.exec_max = 0;
+ p->se.wait_max = 0;
+ p->se.wait_runtime_overruns = 0;
+ p->se.wait_runtime_underruns = 0;
+#endif
+
+ INIT_LIST_HEAD(&p->run_list);
+ p->se.on_rq = 0;
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+ INIT_HLIST_HEAD(&p->preempt_notifiers);
#endif
- set_task_cpu(p, cpu);
/*
* 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 */
+ update_rq_clock(rq);
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;
- } else {
- this_rq = cpu_rq(this_cpu);
+ if (rt_prio(p->prio))
+ p->sched_class = &rt_sched_class;
+ else
+ p->sched_class = &fair_sched_class;
- /*
- * Not the local CPU - must adjust timestamp. This should
- * get optimised away in the !CONFIG_SMP case.
- */
- 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);
+ if (!p->sched_class->task_new || !sysctl_sched_child_runs_first ||
+ (clone_flags & CLONE_VM) || task_cpu(p) != this_cpu ||
+ !current->se.on_rq) {
+ activate_task(rq, p, 0);
+ } else {
/*
- * Parent and child are on different CPUs, now get the
- * parent runqueue to update the parent's ->sleep_avg:
+ * Let the scheduling class do new task startup
+ * management (if any):
*/
- task_rq_unlock(rq, &flags);
- this_rq = task_rq_lock(current, &flags);
+ p->sched_class->task_new(rq, p);
+ inc_nr_running(p, rq);
}
- current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) *
- PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS);
- task_rq_unlock(this_rq, &flags);
+ check_preempt_curr(rq, p);
+ task_rq_unlock(rq, &flags);
+}
+
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+
+/**
+ * preempt_notifier_register - tell me when current is being being preempted & rescheduled
+ * @notifier: notifier struct to register
+ */
+void preempt_notifier_register(struct preempt_notifier *notifier)
+{
+ hlist_add_head(¬ifier->link, ¤t->preempt_notifiers);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_register);
+
+/**
+ * preempt_notifier_unregister - no longer interested in preemption notifications
+ * @notifier: notifier struct to unregister
+ *
+ * This is safe to call from within a preemption notifier.
+ */
+void preempt_notifier_unregister(struct preempt_notifier *notifier)
+{
+ hlist_del(¬ifier->link);
+}
+EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
+
+static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+ struct preempt_notifier *notifier;
+ struct hlist_node *node;
+
+ hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
+ notifier->ops->sched_in(notifier, raw_smp_processor_id());
+}
+
+static void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+ struct task_struct *next)
+{
+ struct preempt_notifier *notifier;
+ struct hlist_node *node;
+
+ hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
+ notifier->ops->sched_out(notifier, next);
+}
+
+#else
+
+static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
+{
+}
+
+static void
+fire_sched_out_preempt_notifiers(struct task_struct *curr,
+ struct task_struct *next)
+{
}
+#endif
+
/**
* prepare_task_switch - prepare to switch tasks
* @rq: the runqueue preparing to switch
+ * @prev: the current task that is being switched out
* @next: the task we are going to switch to.
*
* This is called with the rq lock held and interrupts off. It must
* prepare_task_switch sets up locking and calls architecture specific
* hooks.
*/
-static inline void prepare_task_switch(struct rq *rq, struct task_struct *next)
+static inline void
+prepare_task_switch(struct rq *rq, struct task_struct *prev,
+ struct task_struct *next)
{
+ fire_sched_out_preempt_notifiers(prev, next);
prepare_lock_switch(rq, next);
prepare_arch_switch(next);
}
prev_state = prev->state;
finish_arch_switch(prev);
finish_lock_switch(rq, prev);
+ fire_sched_in_preempt_notifiers(current);
if (mm)
mmdrop(mm);
if (unlikely(prev_state == TASK_DEAD)) {
/*
* Remove function-return probe instances associated with this
* task and put them back on the free list.
- */
+ */
kprobe_flush_task(prev);
put_task_struct(prev);
}
* 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, prev, next);
+ mm = next->mm;
+ oldmm = prev->active_mm;
/*
* For paravirt, this is coupled with an exit in switch_to to
* combine the page table reload and the switch backend into
*/
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;
+ 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);
+
+ fair_delta64 = ls->delta_fair + 1;
+ ls->delta_fair = 0;
+
+ exec_delta64 = ls->delta_exec + 1;
+ ls->delta_exec = 0;
+
+ sample_interval64 = this_rq->clock - ls->load_update_last;
+ ls->load_update_last = this_rq->clock;
+
+ 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
*
spin_lock(&rq1->lock);
}
}
+ update_rq_clock(rq1);
+ update_rq_clock(rq2);
}
/*
* 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);
}
/*
if (task_running(rq, p))
return 0;
- /*
- * Aggressive migration if:
- * 1) task is cache cold, or
- * 2) too many balance attempts have failed.
- */
-
- if (sd->nr_balance_failed > sd->cache_nice_tries) {
-#ifdef CONFIG_SCHEDSTATS
- if (task_hot(p, rq->most_recent_timestamp, sd))
- schedstat_inc(sd, lb_hot_gained[idle]);
-#endif
- 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 cpu_idle_type idle,
- int *all_pinned)
+ int *all_pinned, unsigned long *load_moved,
+ int *this_best_prio, 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;
- if (skip_for_load ||
- !can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) {
-
- best_prio_seen |= idx == best_prio;
- if (curr != head)
- goto skip_queue;
- idx++;
- goto skip_bitmap;
+ skip_for_load = (p->se.load.weight >> 1) > rem_load_move +
+ SCHED_LOAD_SCALE_FUZZ;
+ if ((skip_for_load && p->prio >= *this_best_prio) ||
+ !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
+ p = iterator->next(iterator->arg);
+ goto next;
}
- pull_task(busiest, 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_load_move weighted load from busiest to
+ * this_rq, as part of a balancing operation within domain "sd".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
+ unsigned long max_load_move,
+ struct sched_domain *sd, enum cpu_idle_type idle,
+ int *all_pinned)
+{
+ struct sched_class *class = sched_class_highest;
+ unsigned long total_load_moved = 0;
+ int this_best_prio = this_rq->curr->prio;
+
+ do {
+ total_load_moved +=
+ class->load_balance(this_rq, this_cpu, busiest,
+ ULONG_MAX, max_load_move - total_load_moved,
+ sd, idle, all_pinned, &this_best_prio);
+ class = class->next;
+ } while (class && max_load_move > total_load_moved);
+
+ return total_load_moved > 0;
+}
+
+/*
+ * move_one_task tries to move exactly one task from busiest to this_rq, as
+ * part of active balancing operations within "domain".
+ * Returns 1 if successful and 0 otherwise.
+ *
+ * Called with both runqueues locked.
+ */
+static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
+ struct sched_domain *sd, enum cpu_idle_type idle)
+{
+ struct sched_class *class;
+ int this_best_prio = MAX_PRIO;
+
+ for (class = sched_class_highest; class; class = class->next)
+ if (class->load_balance(this_rq, this_cpu, busiest,
+ 1, ULONG_MAX, sd, idle, NULL,
+ &this_best_prio))
+ return 1;
+
+ return 0;
+}
+
+/*
* find_busiest_group finds and returns the busiest CPU group within the
* domain. It calculates and returns the amount of weighted load which
* should be moved to restore balance via the imbalance parameter.
*/
static struct sched_group *
find_busiest_group(struct sched_domain *sd, int this_cpu,
- unsigned long *imbalance, enum cpu_idle_type idle, int *sd_idle,
- cpumask_t *cpus, int *balance)
+ 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;
rq = cpu_rq(i);
- if (*sd_idle && !idle_cpu(i))
+ if (*sd_idle && rq->nr_running)
*sd_idle = 0;
/* Bias balancing toward cpus of our domain */
avg_load += load;
sum_nr_running += rq->nr_running;
- sum_weighted_load += rq->raw_weighted_load;
+ sum_weighted_load += weighted_cpuload(i);
}
/*
* First idle cpu or the first cpu(busiest) in this sched group
* is eligible for doing load balancing at this and above
- * domains.
+ * domains. In the newly idle case, we will allow all the cpu's
+ * to do the newly idle load balance.
*/
- if (local_group && balance_cpu != this_cpu && balance) {
+ if (idle != CPU_NEWLY_IDLE && local_group &&
+ balance_cpu != this_cpu && balance) {
*balance = 0;
goto ret;
}
* Busy processors will not participate in power savings
* balance.
*/
- if (idle == CPU_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
} 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;
}
pwr_move /= SCHED_LOAD_SCALE;
/* Move if we gain throughput */
- if (pwr_move <= pwr_now)
- goto out_balanced;
-
- *imbalance = busiest_load_per_task;
+ if (pwr_move > pwr_now)
+ *imbalance = busiest_load_per_task;
}
return busiest;
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;
}
}
*/
#define MAX_PINNED_INTERVAL 512
-static inline unsigned long minus_1_or_zero(unsigned long n)
-{
- return n > 0 ? n - 1 : 0;
-}
-
/*
* Check this_cpu to ensure it is balanced within domain. Attempt to move
* tasks if there is an imbalance.
struct sched_domain *sd, enum cpu_idle_type idle,
int *balance)
{
- int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
+ int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
struct sched_group *group;
unsigned long imbalance;
struct rq *busiest;
/*
* 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
+ * let the state of idle sibling percolate up as CPU_IDLE, instead of
* portraying it as CPU_NOT_IDLE.
*/
if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
schedstat_add(sd, lb_imbalance[idle], imbalance);
- nr_moved = 0;
+ ld_moved = 0;
if (busiest->nr_running > 1) {
/*
* Attempt to move tasks. If find_busiest_group has found
* an imbalance but busiest->nr_running <= 1, the group is
- * still unbalanced. nr_moved simply stays zero, so it is
+ * still unbalanced. ld_moved simply stays zero, so it is
* correctly treated as an imbalance.
*/
local_irq_save(flags);
double_rq_lock(this_rq, busiest);
- nr_moved = move_tasks(this_rq, this_cpu, busiest,
- minus_1_or_zero(busiest->nr_running),
+ ld_moved = move_tasks(this_rq, this_cpu, busiest,
imbalance, sd, idle, &all_pinned);
double_rq_unlock(this_rq, busiest);
local_irq_restore(flags);
/*
* some other cpu did the load balance for us.
*/
- if (nr_moved && this_cpu != smp_processor_id())
+ if (ld_moved && this_cpu != smp_processor_id())
resched_cpu(this_cpu);
/* All tasks on this runqueue were pinned by CPU affinity */
}
}
- if (!nr_moved) {
+ if (!ld_moved) {
schedstat_inc(sd, lb_failed[idle]);
sd->nr_balance_failed++;
sd->balance_interval *= 2;
}
- if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
+ if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
return -1;
- return nr_moved;
+ return ld_moved;
out_balanced:
schedstat_inc(sd, lb_balanced[idle]);
struct sched_group *group;
struct rq *busiest = NULL;
unsigned long imbalance;
- int nr_moved = 0;
+ int ld_moved = 0;
int sd_idle = 0;
+ int all_pinned = 0;
cpumask_t cpus = CPU_MASK_ALL;
/*
schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
- nr_moved = 0;
+ ld_moved = 0;
if (busiest->nr_running > 1) {
/* Attempt to move tasks */
double_lock_balance(this_rq, busiest);
- nr_moved = move_tasks(this_rq, this_cpu, busiest,
- minus_1_or_zero(busiest->nr_running),
- imbalance, sd, CPU_NEWLY_IDLE, NULL);
+ /* this_rq->clock is already updated */
+ update_rq_clock(busiest);
+ ld_moved = move_tasks(this_rq, this_cpu, busiest,
+ imbalance, sd, CPU_NEWLY_IDLE,
+ &all_pinned);
spin_unlock(&busiest->lock);
- if (!nr_moved) {
+ if (unlikely(all_pinned)) {
cpu_clear(cpu_of(busiest), cpus);
if (!cpus_empty(cpus))
goto redo;
}
}
- if (!nr_moved) {
+ if (!ld_moved) {
schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
!test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
} else
sd->nr_balance_failed = 0;
- return nr_moved;
+ return ld_moved;
out_balanced:
schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
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) {
unsigned long 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;
+ }
}
/*
/* move a task from busiest_rq to target_rq */
double_lock_balance(busiest_rq, target_rq);
+ update_rq_clock(busiest_rq);
+ update_rq_clock(target_rq);
/* Search for an sd spanning us and the target CPU. */
for_each_domain(target_cpu, sd) {
if (likely(sd)) {
schedstat_inc(sd, alb_cnt);
- if (move_tasks(target_rq, target_cpu, busiest_rq, 1,
- RTPRIO_TO_LOAD_WEIGHT(100), sd, CPU_IDLE,
- NULL))
+ if (move_one_task(target_rq, target_cpu, busiest_rq,
+ sd, CPU_IDLE))
schedstat_inc(sd, alb_pushed);
else
schedstat_inc(sd, alb_failed);
spin_unlock(&target_rq->lock);
}
-static void update_load(struct rq *this_rq)
-{
- unsigned long this_load;
- unsigned int i, scale;
-
- this_load = this_rq->raw_weighted_load;
-
- /* Update our load: */
- for (i = 0, scale = 1; i < 3; i++, scale += scale) {
- unsigned long old_load, new_load;
-
- /* scale is effectively 1 << i now, and >> i divides by scale */
-
- old_load = this_rq->cpu_load[i];
- new_load = this_load;
- /*
- * Round up the averaging division if load is increasing. This
- * prevents us from getting stuck on 9 if the load is 10, for
- * example.
- */
- if (new_load > old_load)
- new_load += scale-1;
- this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
- }
-}
-
#ifdef CONFIG_NO_HZ
static struct {
atomic_t load_balancer;
struct sched_domain *sd;
/* Earliest time when we have to do rebalance again */
unsigned long next_balance = jiffies + 60*HZ;
+ int update_next_balance = 0;
for_each_domain(cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
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 (sd->flags & SD_SERIALIZE)
spin_unlock(&balancing);
out:
- if (time_after(next_balance, sd->last_balance + interval))
+ if (time_after(next_balance, sd->last_balance + interval)) {
next_balance = sd->last_balance + interval;
+ update_next_balance = 1;
+ }
/*
* Stop the load balance at this level. There is another
if (!balance)
break;
}
- rq->next_balance = next_balance;
+
+ /*
+ * next_balance will be updated only when there is a need.
+ * When the cpu is attached to null domain for ex, it will not be
+ * updated.
+ */
+ if (likely(update_next_balance))
+ rq->next_balance = next_balance;
}
/*
*/
static void run_rebalance_domains(struct softirq_action *h)
{
- int local_cpu = smp_processor_id();
- struct rq *local_rq = cpu_rq(local_cpu);
- enum cpu_idle_type idle = local_rq->idle_at_tick ? CPU_IDLE : CPU_NOT_IDLE;
+ int this_cpu = smp_processor_id();
+ struct rq *this_rq = cpu_rq(this_cpu);
+ enum cpu_idle_type idle = this_rq->idle_at_tick ?
+ CPU_IDLE : CPU_NOT_IDLE;
- rebalance_domains(local_cpu, idle);
+ rebalance_domains(this_cpu, idle);
#ifdef CONFIG_NO_HZ
/*
* balancing on behalf of the other idle cpus whose ticks are
* stopped.
*/
- if (local_rq->idle_at_tick &&
- atomic_read(&nohz.load_balancer) == local_cpu) {
+ 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(local_cpu, cpus);
+ cpu_clear(this_cpu, cpus);
for_each_cpu_mask(balance_cpu, cpus) {
/*
* If this cpu gets work to do, stop the load balancing
rebalance_domains(balance_cpu, CPU_IDLE);
rq = cpu_rq(balance_cpu);
- if (time_after(local_rq->next_balance, rq->next_balance))
- local_rq->next_balance = rq->next_balance;
+ if (time_after(this_rq->next_balance, rq->next_balance))
+ this_rq->next_balance = rq->next_balance;
}
}
#endif
* idle load balancing owner or decide to stop the periodic load balancing,
* if the whole system is idle.
*/
-static inline void trigger_load_balance(int cpu)
+static inline void trigger_load_balance(struct rq *rq, int cpu)
{
- struct rq *rq = cpu_rq(cpu);
#ifdef CONFIG_NO_HZ
/*
* If we were in the nohz mode recently and busy at the current
if (time_after_eq(jiffies, rq->next_balance))
raise_softirq(SCHED_SOFTIRQ);
}
-#else
+
+#else /* CONFIG_SMP */
+
/*
* on UP we do not need to balance between CPUs:
*/
static inline void idle_balance(int cpu, struct rq *rq)
{
}
+
+/* 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, struct rq_iterator *iterator)
+{
+ *load_moved = 0;
+
+ return 0;
+}
+
#endif
DEFINE_PER_CPU(struct kernel_stat, kstat);
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;
+ update_rq_clock(rq);
+ delta_exec = rq->clock - p->se.exec_start;
if ((s64)delta_exec > 0)
ns += delta_exec;
}
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)) {
- 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)
{
- struct task_struct *p = current;
int cpu = smp_processor_id();
- int idle_at_tick = idle_cpu(cpu);
struct rq *rq = cpu_rq(cpu);
+ struct task_struct *curr = rq->curr;
+ u64 next_tick = rq->tick_timestamp + TICK_NSEC;
+
+ spin_lock(&rq->lock);
+ __update_rq_clock(rq);
+ /*
+ * Let rq->clock advance by at least TICK_NSEC:
+ */
+ if (unlikely(rq->clock < next_tick))
+ rq->clock = next_tick;
+ rq->tick_timestamp = rq->clock;
+ update_cpu_load(rq);
+ if (curr != rq->idle) /* FIXME: needed? */
+ curr->sched_class->task_tick(rq, curr);
+ spin_unlock(&rq->lock);
- if (!idle_at_tick)
- task_running_tick(rq, p);
#ifdef CONFIG_SMP
- update_load(rq);
- rq->idle_at_tick = idle_at_tick;
- trigger_load_balance(cpu);
+ rq->idle_at_tick = idle_cpu(cpu);
+ trigger_load_balance(rq, cpu);
#endif
}
if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
return;
/*
- * Is the spinlock portion underflowing?
+ * Is the spinlock portion underflowing?
+ */
+ if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
+ !(preempt_count() & PREEMPT_MASK)))
+ return;
+
+ preempt_count() -= val;
+}
+EXPORT_SYMBOL(sub_preempt_count);
+
+#endif
+
+/*
+ * Print scheduling while atomic bug:
+ */
+static noinline void __schedule_bug(struct task_struct *prev)
+{
+ 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();
+}
+
+/*
+ * Various schedule()-time debugging checks and statistics:
+ */
+static inline void schedule_debug(struct task_struct *prev)
+{
+ /*
+ * Test if we are atomic. Since do_exit() needs to call into
+ * schedule() atomically, we ignore that path for now.
+ * Otherwise, whine if we are scheduling when we should not be.
+ */
+ if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state))
+ __schedule_bug(prev);
+
+ profile_hit(SCHED_PROFILING, __builtin_return_address(0));
+
+ schedstat_inc(this_rq(), sched_cnt);
+}
+
+/*
+ * Pick up the highest-prio task:
+ */
+static inline struct task_struct *
+pick_next_task(struct rq *rq, struct task_struct *prev)
+{
+ struct sched_class *class;
+ struct task_struct *p;
+
+ /*
+ * Optimization: we know that if all tasks are in
+ * the fair class we can call that function directly:
*/
- if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
- !(preempt_count() & PREEMPT_MASK)))
- return;
+ if (likely(rq->nr_running == rq->cfs.nr_running)) {
+ p = fair_sched_class.pick_next_task(rq);
+ if (likely(p))
+ return p;
+ }
- preempt_count() -= val;
+ class = sched_class_highest;
+ for ( ; ; ) {
+ p = class->pick_next_task(rq);
+ if (p)
+ return p;
+ /*
+ * Will never be NULL as the idle class always
+ * returns a non-NULL p:
+ */
+ class = class->next;
+ }
}
-EXPORT_SYMBOL(sub_preempt_count);
-
-#endif
/*
* schedule() is the main scheduler function.
asmlinkage void __sched schedule(void)
{
struct task_struct *prev, *next;
- struct prio_array *array;
- struct list_head *queue;
- unsigned long long now;
- unsigned long run_time;
- int cpu, idx;
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));
+ int cpu;
need_resched:
preempt_disable();
- prev = current;
+ cpu = smp_processor_id();
+ rq = cpu_rq(cpu);
+ rcu_qsctr_inc(cpu);
+ prev = rq->curr;
+ switch_count = &prev->nivcsw;
+
release_kernel_lock(prev);
need_resched_nonpreemptible:
- rq = this_rq();
-
- /*
- * The idle thread is not allowed to schedule!
- * Remove this check after it has been exercised a bit.
- */
- if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) {
- printk(KERN_ERR "bad: scheduling from the idle thread!\n");
- dump_stack();
- }
-
- schedstat_inc(rq, sched_cnt);
- now = sched_clock();
- if (likely((long long)(now - prev->timestamp) < NS_MAX_SLEEP_AVG)) {
- run_time = now - prev->timestamp;
- if (unlikely((long long)(now - prev->timestamp) < 0))
- run_time = 0;
- } else
- run_time = NS_MAX_SLEEP_AVG;
- /*
- * Tasks charged proportionately less run_time at high sleep_avg to
- * delay them losing their interactive status
- */
- run_time /= (CURRENT_BONUS(prev) ? : 1);
+ schedule_debug(prev);
spin_lock_irq(&rq->lock);
+ clear_tsk_need_resched(prev);
+ __update_rq_clock(rq);
- 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))))
+ unlikely(signal_pending(prev)))) {
prev->state = TASK_RUNNING;
- else {
- if (prev->state == TASK_UNINTERRUPTIBLE)
- rq->nr_uninterruptible++;
- deactivate_task(prev, rq);
+ } else {
+ deactivate_task(rq, prev, 1);
}
+ switch_count = &prev->nvcsw;
}
- cpu = smp_processor_id();
- if (unlikely(!rq->nr_running)) {
+ if (unlikely(!rq->nr_running))
idle_balance(cpu, rq);
- if (!rq->nr_running) {
- next = rq->idle;
- rq->expired_timestamp = 0;
- goto switch_tasks;
- }
- }
-
- array = rq->active;
- if (unlikely(!array->nr_active)) {
- /*
- * Switch the active and expired arrays.
- */
- schedstat_inc(rq, sched_switch);
- rq->active = rq->expired;
- rq->expired = array;
- array = rq->active;
- rq->expired_timestamp = 0;
- rq->best_expired_prio = MAX_PRIO;
- }
-
- idx = sched_find_first_bit(array->bitmap);
- queue = array->queue + idx;
- next = list_entry(queue->next, struct task_struct, run_list);
-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));
-
- prev->timestamp = prev->last_ran = now;
+ prev->sched_class->put_prev_task(rq, prev);
+ next = pick_next_task(rq, prev);
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;
BUG_ON(prio < 0 || prio > MAX_PRIO);
rq = task_rq_lock(p, &flags);
+ update_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);
+
+ 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);
/*
* 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;
* the task might be in the middle of scheduling on another CPU.
*/
rq = task_rq_lock(p, &flags);
+ update_rq_clock(rq);
/*
* The RT priorities are set via sched_setscheduler(), but we still
* allow the 'normal' nice value to be set - but as expected
* it wont have any effect on scheduling until the task is
- * not SCHED_NORMAL/SCHED_BATCH:
+ * SCHED_FIFO/SCHED_RR:
*/
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);
+ dec_load(rq, p);
}
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);
+ inc_load(rq, p);
/*
* 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 */
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) ||
if (!capable(CAP_SYS_NICE)) {
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);
+ update_rq_clock(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);
out_unlock:
read_unlock(&tasklist_lock);
mutex_unlock(&sched_hotcpu_mutex);
- if (retval)
- return retval;
- return 0;
+ 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) {
- 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);
+ current->sched_class->yield_task(rq, current);
/*
* Since we are going to call schedule() anyway, there's
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:
void __cpuinit init_idle_bootup_task(struct task_struct *idle)
{
- /* nothing yet */
+ idle->sched_class = &idle_sched_class;
}
/**
struct rq *rq = cpu_rq(cpu);
unsigned long flags;
- idle->timestamp = sched_clock();
- 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 limit = 100000000;
+
+ sysctl_sched_min_granularity *= factor;
+ if (sysctl_sched_min_granularity > limit)
+ sysctl_sched_min_granularity = limit;
+
+ sysctl_sched_latency *= factor;
+ if (sysctl_sched_latency > limit)
+ sysctl_sched_latency = limit;
+
+ sysctl_sched_runtime_limit = sysctl_sched_latency;
+ sysctl_sched_wakeup_granularity = sysctl_sched_min_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];
+ for ( ; ; ) {
+ if (!rq->nr_running)
+ break;
+ update_rq_clock(rq);
+ next = pick_next_task(rq, rq->curr);
+ if (!next)
+ break;
+ migrate_dead(dead_cpu, next);
- while (!list_empty(list))
- migrate_dead(dead_cpu, list_entry(list->next,
- struct task_struct, run_list));
- }
}
}
#endif /* CONFIG_HOTPLUG_CPU */
+#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
+
+static struct ctl_table sd_ctl_dir[] = {
+ {
+ .procname = "sched_domain",
+ .mode = 0555,
+ },
+ {0,},
+};
+
+static struct ctl_table sd_ctl_root[] = {
+ {
+ .ctl_name = CTL_KERN,
+ .procname = "kernel",
+ .mode = 0555,
+ .child = sd_ctl_dir,
+ },
+ {0,},
+};
+
+static struct ctl_table *sd_alloc_ctl_entry(int n)
+{
+ struct ctl_table *entry =
+ kmalloc(n * sizeof(struct ctl_table), GFP_KERNEL);
+
+ BUG_ON(!entry);
+ memset(entry, 0, n * sizeof(struct ctl_table));
+
+ return entry;
+}
+
+static void
+set_table_entry(struct ctl_table *entry,
+ const char *procname, void *data, int maxlen,
+ mode_t mode, proc_handler *proc_handler)
+{
+ entry->procname = procname;
+ entry->data = data;
+ entry->maxlen = maxlen;
+ entry->mode = mode;
+ entry->proc_handler = proc_handler;
+}
+
+static struct ctl_table *
+sd_alloc_ctl_domain_table(struct sched_domain *sd)
+{
+ struct ctl_table *table = sd_alloc_ctl_entry(14);
+
+ set_table_entry(&table[0], "min_interval", &sd->min_interval,
+ sizeof(long), 0644, proc_doulongvec_minmax);
+ set_table_entry(&table[1], "max_interval", &sd->max_interval,
+ sizeof(long), 0644, proc_doulongvec_minmax);
+ set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[10], "cache_nice_tries",
+ &sd->cache_nice_tries,
+ sizeof(int), 0644, proc_dointvec_minmax);
+ set_table_entry(&table[12], "flags", &sd->flags,
+ sizeof(int), 0644, proc_dointvec_minmax);
+
+ return table;
+}
+
+static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
+{
+ struct ctl_table *entry, *table;
+ struct sched_domain *sd;
+ int domain_num = 0, i;
+ char buf[32];
+
+ for_each_domain(cpu, sd)
+ domain_num++;
+ entry = table = sd_alloc_ctl_entry(domain_num + 1);
+
+ i = 0;
+ for_each_domain(cpu, sd) {
+ snprintf(buf, 32, "domain%d", i);
+ entry->procname = kstrdup(buf, GFP_KERNEL);
+ entry->mode = 0555;
+ entry->child = sd_alloc_ctl_domain_table(sd);
+ entry++;
+ i++;
+ }
+ return table;
+}
+
+static struct ctl_table_header *sd_sysctl_header;
+static void init_sched_domain_sysctl(void)
+{
+ int i, cpu_num = num_online_cpus();
+ struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
+ char buf[32];
+
+ sd_ctl_dir[0].child = entry;
+
+ for (i = 0; i < cpu_num; i++, entry++) {
+ snprintf(buf, 32, "cpu%d", i);
+ entry->procname = kstrdup(buf, GFP_KERNEL);
+ entry->mode = 0555;
+ entry->child = sd_alloc_ctl_cpu_table(i);
+ }
+ sd_sysctl_header = register_sysctl_table(sd_ctl_root);
+}
+#else
+static void init_sched_domain_sysctl(void)
+{
+}
+#endif
+
/*
* migration_call - callback that gets triggered when a CPU is added.
* Here we can start up the necessary migration thread for the new CPU.
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
- p = kthread_create(migration_thread, hcpu, "migration/%d",cpu);
+ 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;
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);
+ update_rq_clock(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);
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;
}
/* 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);
}
}
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
-int arch_reinit_sched_domains(void)
+static int arch_reinit_sched_domains(void)
{
int err;
return ret ? ret : count;
}
-int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
-{
- int err = 0;
-
-#ifdef CONFIG_SCHED_SMT
- if (smt_capable())
- err = sysfs_create_file(&cls->kset.kobj,
- &attr_sched_smt_power_savings.attr);
-#endif
-#ifdef CONFIG_SCHED_MC
- if (!err && mc_capable())
- err = sysfs_create_file(&cls->kset.kobj,
- &attr_sched_mc_power_savings.attr);
-#endif
- return err;
-}
-#endif
-
#ifdef CONFIG_SCHED_MC
static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page)
{
{
return sched_power_savings_store(buf, count, 0);
}
-SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
- sched_mc_power_savings_store);
+static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
+ sched_mc_power_savings_store);
#endif
#ifdef CONFIG_SCHED_SMT
{
return sched_power_savings_store(buf, count, 1);
}
-SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
- sched_smt_power_savings_store);
+static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
+ sched_smt_power_savings_store);
+#endif
+
+int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
+{
+ int err = 0;
+
+#ifdef CONFIG_SCHED_SMT
+ if (smt_capable())
+ err = sysfs_create_file(&cls->kset.kobj,
+ &attr_sched_smt_power_savings.attr);
+#endif
+#ifdef CONFIG_SCHED_MC
+ if (!err && mc_capable())
+ err = sysfs_create_file(&cls->kset.kobj,
+ &attr_sched_mc_power_savings.attr);
+#endif
+ return err;
+}
#endif
/*
/* XXX: Theoretical race here - CPU may be hotplugged now */
hotcpu_notifier(update_sched_domains, 0);
+ init_sched_domain_sysctl();
+
/* 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);
+#ifdef CONFIG_PREEMPT_NOTIFIERS
+ INIT_HLIST_HEAD(&init_task.preempt_notifiers);
+#endif
+
#ifdef CONFIG_SMP
nr_cpu_ids = highest_cpu + 1;
open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
* 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 *g, *p;
unsigned long flags;
struct rq *rq;
+ int on_rq;
read_lock_irq(&tasklist_lock);
-
do_each_thread(g, p) {
- if (!rt_task(p))
+ p->se.fair_key = 0;
+ p->se.wait_runtime = 0;
+ p->se.exec_start = 0;
+ p->se.wait_start_fair = 0;
+ p->se.sleep_start_fair = 0;
+#ifdef CONFIG_SCHEDSTATS
+ p->se.wait_start = 0;
+ p->se.sleep_start = 0;
+ p->se.block_start = 0;
+#endif
+ 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));
+ update_rq_clock(rq);
+ on_rq = p->se.on_rq;
+ if (on_rq)
+ deactivate_task(rq, p, 0);
+ __setscheduler(rq, p, SCHED_NORMAL, 0);
+ if (on_rq) {
+ activate_task(rq, p, 0);
resched_task(rq->curr);
}
-
+#ifdef CONFIG_SMP
+ out_unlock:
+#endif
__task_rq_unlock(rq);
spin_unlock_irqrestore(&p->pi_lock, flags);
} while_each_thread(g, p);
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff