#include <mach/boolean.h>
#include <mach/kern_return.h>
#include <mach/machine.h>
#include <kern/host.h>
#include <kern/mach_param.h>
#include <kern/sched.h>
#include <sys/kdebug.h>
#include <kern/spl.h>
#include <kern/thread.h>
#include <kern/processor.h>
#include <kern/ledger.h>
#include <machine/machparam.h>
#include <kern/machine.h>
#ifdef CONFIG_MACH_APPROXIMATE_TIME
#include <machine/commpage.h>
#endif
#if MONOTONIC
#include <kern/monotonic.h>
#endif
static void sched_update_thread_bucket(thread_t thread);
void
thread_quantum_expire(
timer_call_param_t p0,
timer_call_param_t p1)
{
processor_t processor = p0;
thread_t thread = p1;
ast_t preempt;
uint64_t ctime;
int urgency;
uint64_t ignore1, ignore2;
assert(processor == current_processor());
assert(thread == current_thread());
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_QUANTUM_EXPIRED) | DBG_FUNC_START, 0, 0, 0, 0, 0);
SCHED_STATS_QUANTUM_TIMER_EXPIRATION(processor);
ledger_credit(thread->t_ledger, task_ledgers.cpu_time, thread->quantum_remaining);
ledger_credit(thread->t_threadledger, thread_ledgers.cpu_time, thread->quantum_remaining);
if (thread->t_bankledger) {
ledger_credit(thread->t_bankledger, bank_ledgers.cpu_time,
(thread->quantum_remaining - thread->t_deduct_bank_ledger_time));
}
thread->t_deduct_bank_ledger_time = 0;
ctime = mach_absolute_time();
#ifdef CONFIG_MACH_APPROXIMATE_TIME
commpage_update_mach_approximate_time(ctime);
#endif
#if MONOTONIC
mt_sched_update(thread);
#endif
thread_lock(thread);
processor->last_dispatch = ctime;
thread->last_run_time = ctime;
if ((thread->sched_mode == TH_MODE_REALTIME || thread->sched_mode == TH_MODE_FIXED) &&
!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) &&
!(thread->options & TH_OPT_SYSTEM_CRITICAL)) {
uint64_t new_computation;
new_computation = ctime - thread->computation_epoch;
new_computation += thread->computation_metered;
if (new_computation > max_unsafe_computation) {
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_FAILSAFE)|DBG_FUNC_NONE,
(uintptr_t)thread->sched_pri, (uintptr_t)thread->sched_mode, 0, 0, 0);
thread->safe_release = ctime + sched_safe_duration;
sched_thread_mode_demote(thread, TH_SFLAG_FAILSAFE);
}
}
if (SCHED(can_update_priority)(thread))
SCHED(update_priority)(thread);
else
SCHED(lightweight_update_priority)(thread);
if (thread->sched_mode != TH_MODE_REALTIME)
SCHED(quantum_expire)(thread);
processor_state_update_from_thread(processor, thread);
processor->first_timeslice = FALSE;
thread_quantum_init(thread);
thread->precise_user_kernel_time = use_precise_user_kernel_time(thread);
if (!thread->precise_user_kernel_time) {
timer_switch(PROCESSOR_DATA(processor, current_state),
ctime,
PROCESSOR_DATA(processor, current_state));
timer_switch(PROCESSOR_DATA(processor, thread_timer),
ctime,
PROCESSOR_DATA(processor, thread_timer));
}
processor->quantum_end = ctime + thread->quantum_remaining;
ast_t check_reason = AST_QUANTUM;
if (thread->task == kernel_task)
check_reason |= AST_URGENT;
if ((preempt = csw_check(processor, check_reason)) != AST_NONE)
ast_on(preempt);
ast_propagate(thread);
thread_unlock(thread);
timer_call_quantum_timer_enter(&processor->quantum_timer, thread,
processor->quantum_end, ctime);
urgency = thread_get_urgency(thread, &ignore1, &ignore2);
machine_thread_going_on_core(thread, urgency, 0, 0, ctime);
machine_switch_perfcontrol_state_update(QUANTUM_EXPIRY, ctime,
0, thread);
#if defined(CONFIG_SCHED_TIMESHARE_CORE)
sched_timeshare_consider_maintenance(ctime);
#endif
#if __arm__ || __arm64__
if (thread->sched_mode == TH_MODE_REALTIME)
sched_consider_recommended_cores(ctime, thread);
#endif
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_QUANTUM_EXPIRED) | DBG_FUNC_END, preempt, 0, 0, 0, 0);
}
void
sched_set_thread_base_priority(thread_t thread, int priority)
{
assert(priority >= MINPRI);
uint64_t ctime = 0;
if (thread->sched_mode == TH_MODE_REALTIME)
assert(priority <= BASEPRI_RTQUEUES);
else
assert(priority < BASEPRI_RTQUEUES);
int old_base_pri = thread->base_pri;
thread->base_pri = priority;
if ((thread->state & TH_RUN) == TH_RUN) {
assert(thread->last_made_runnable_time != THREAD_NOT_RUNNABLE);
ctime = mach_approximate_time();
thread->last_basepri_change_time = ctime;
} else {
assert(thread->last_basepri_change_time == THREAD_NOT_RUNNABLE);
assert(thread->last_made_runnable_time == THREAD_NOT_RUNNABLE);
}
if (thread == current_thread() && old_base_pri != priority) {
if (!ctime) {
ctime = mach_approximate_time();
}
machine_switch_perfcontrol_state_update(PERFCONTROL_ATTR_UPDATE,
ctime, PERFCONTROL_CALLOUT_WAKE_UNSAFE, thread);
}
sched_update_thread_bucket(thread);
thread_recompute_sched_pri(thread, FALSE);
}
void
thread_recompute_sched_pri(
thread_t thread,
boolean_t override_depress)
{
int priority;
if (thread->sched_mode == TH_MODE_TIMESHARE)
priority = SCHED(compute_timeshare_priority)(thread);
else
priority = thread->base_pri;
if ((!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) || (priority > thread->sched_pri)) &&
(!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) || override_depress)) {
set_sched_pri(thread, priority);
}
}
void
sched_default_quantum_expire(thread_t thread __unused)
{
}
#if defined(CONFIG_SCHED_TIMESHARE_CORE)
void
lightweight_update_priority(thread_t thread)
{
assert(thread->runq == PROCESSOR_NULL);
assert(thread == current_thread());
if (thread->sched_mode == TH_MODE_TIMESHARE) {
int priority;
uint32_t delta;
thread_timer_delta(thread, delta);
if (thread->pri_shift < INT8_MAX)
thread->sched_usage += delta;
thread->cpu_delta += delta;
priority = sched_compute_timeshare_priority(thread);
if ((!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) || (priority > thread->sched_pri)) &&
(!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)) &&
priority != thread->sched_pri) {
thread->sched_pri = priority;
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_CHANGE_PRIORITY),
(uintptr_t)thread_tid(thread),
thread->base_pri,
thread->sched_pri,
thread->sched_usage,
0);
}
}
}
struct shift_data {
int shift1;
int shift2;
};
#define SCHED_DECAY_TICKS 32
static struct shift_data sched_decay_shifts[SCHED_DECAY_TICKS] = {
{1,1},{1,3},{1,-3},{2,-7},{3,5},{3,-5},{4,-8},{5,7},
{5,-7},{6,-10},{7,10},{7,-9},{8,-11},{9,12},{9,-11},{10,-13},
{11,14},{11,-13},{12,-15},{13,17},{13,-15},{14,-17},{15,19},{16,18},
{16,-19},{17,22},{18,20},{18,-20},{19,26},{20,22},{20,-22},{21,-27}
};
extern int sched_pri_decay_band_limit;
#ifdef CONFIG_EMBEDDED
int
sched_compute_timeshare_priority(thread_t thread)
{
int decay_amount = (thread->sched_usage >> thread->pri_shift);
int decay_limit = sched_pri_decay_band_limit;
if (thread->base_pri > BASEPRI_FOREGROUND) {
decay_limit += (thread->base_pri - BASEPRI_FOREGROUND);
}
if (decay_amount > decay_limit) {
decay_amount = decay_limit;
}
int priority = thread->base_pri - decay_amount;
if (priority < MAXPRI_THROTTLE) {
if (thread->task->max_priority > MAXPRI_THROTTLE) {
priority = MAXPRI_THROTTLE;
} else if (priority < MINPRI_USER) {
priority = MINPRI_USER;
}
} else if (priority > MAXPRI_KERNEL) {
priority = MAXPRI_KERNEL;
}
return priority;
}
#else
int
sched_compute_timeshare_priority(thread_t thread)
{
int priority = thread->base_pri - (thread->sched_usage >> thread->pri_shift);
if (priority < MINPRI_USER)
priority = MINPRI_USER;
else if (priority > MAXPRI_KERNEL)
priority = MAXPRI_KERNEL;
return priority;
}
#endif
boolean_t
can_update_priority(
thread_t thread)
{
if (sched_tick == thread->sched_stamp)
return (FALSE);
else
return (TRUE);
}
void
update_priority(
thread_t thread)
{
uint32_t ticks, delta;
ticks = sched_tick - thread->sched_stamp;
assert(ticks != 0);
thread->sched_stamp += ticks;
thread->pri_shift = sched_pri_shifts[thread->th_sched_bucket];
if (sched_decay_usage_age_factor > 1)
ticks *= sched_decay_usage_age_factor;
thread_timer_delta(thread, delta);
if (ticks < SCHED_DECAY_TICKS) {
if (thread->pri_shift < INT8_MAX)
thread->sched_usage += delta;
thread->cpu_usage += delta + thread->cpu_delta;
thread->cpu_delta = 0;
struct shift_data *shiftp = &sched_decay_shifts[ticks];
if (shiftp->shift2 > 0) {
thread->cpu_usage = (thread->cpu_usage >> shiftp->shift1) +
(thread->cpu_usage >> shiftp->shift2);
thread->sched_usage = (thread->sched_usage >> shiftp->shift1) +
(thread->sched_usage >> shiftp->shift2);
} else {
thread->cpu_usage = (thread->cpu_usage >> shiftp->shift1) -
(thread->cpu_usage >> -(shiftp->shift2));
thread->sched_usage = (thread->sched_usage >> shiftp->shift1) -
(thread->sched_usage >> -(shiftp->shift2));
}
} else {
thread->cpu_usage = thread->cpu_delta = 0;
thread->sched_usage = 0;
}
if ((thread->sched_flags & TH_SFLAG_FAILSAFE) &&
mach_absolute_time() >= thread->safe_release) {
sched_thread_mode_undemote(thread, TH_SFLAG_FAILSAFE);
}
if (thread->sched_mode == TH_MODE_TIMESHARE) {
int priority = sched_compute_timeshare_priority(thread);
if ((!(thread->sched_flags & TH_SFLAG_PROMOTED_MASK) || (priority > thread->sched_pri)) &&
(!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)) &&
priority != thread->sched_pri) {
boolean_t removed = thread_run_queue_remove(thread);
thread->sched_pri = priority;
KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_CHANGE_PRIORITY),
(uintptr_t)thread_tid(thread),
thread->base_pri,
thread->sched_pri,
thread->sched_usage,
0);
if (removed)
thread_run_queue_reinsert(thread, SCHED_TAILQ);
}
}
return;
}
#endif
volatile uint32_t sched_run_buckets[TH_BUCKET_MAX];
static void
sched_incr_bucket(sched_bucket_t bucket)
{
assert(bucket >= TH_BUCKET_FIXPRI &&
bucket <= TH_BUCKET_SHARE_BG);
hw_atomic_add(&sched_run_buckets[bucket], 1);
}
static void
sched_decr_bucket(sched_bucket_t bucket)
{
assert(bucket >= TH_BUCKET_FIXPRI &&
bucket <= TH_BUCKET_SHARE_BG);
assert(sched_run_buckets[bucket] > 0);
hw_atomic_sub(&sched_run_buckets[bucket], 1);
}
uint32_t
sched_run_incr(thread_t thread)
{
assert((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN);
uint32_t new_count = hw_atomic_add(&sched_run_buckets[TH_BUCKET_RUN], 1);
sched_incr_bucket(thread->th_sched_bucket);
return new_count;
}
uint32_t
sched_run_decr(thread_t thread)
{
assert((thread->state & (TH_RUN|TH_IDLE)) != TH_RUN);
sched_decr_bucket(thread->th_sched_bucket);
uint32_t new_count = hw_atomic_sub(&sched_run_buckets[TH_BUCKET_RUN], 1);
return new_count;
}
static void
sched_update_thread_bucket(thread_t thread)
{
sched_bucket_t old_bucket = thread->th_sched_bucket;
sched_bucket_t new_bucket = TH_BUCKET_RUN;
switch (thread->sched_mode) {
case TH_MODE_FIXED:
case TH_MODE_REALTIME:
new_bucket = TH_BUCKET_FIXPRI;
break;
case TH_MODE_TIMESHARE:
if (thread->base_pri > BASEPRI_UTILITY)
new_bucket = TH_BUCKET_SHARE_FG;
else if (thread->base_pri > MAXPRI_THROTTLE)
new_bucket = TH_BUCKET_SHARE_UT;
else
new_bucket = TH_BUCKET_SHARE_BG;
break;
default:
panic("unexpected mode: %d", thread->sched_mode);
break;
}
if (old_bucket != new_bucket) {
thread->th_sched_bucket = new_bucket;
thread->pri_shift = sched_pri_shifts[new_bucket];
if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) {
sched_decr_bucket(old_bucket);
sched_incr_bucket(new_bucket);
}
}
}
void
sched_set_thread_mode(thread_t thread, sched_mode_t new_mode)
{
assert(thread->runq == PROCESSOR_NULL);
switch (new_mode) {
case TH_MODE_FIXED:
case TH_MODE_REALTIME:
case TH_MODE_TIMESHARE:
break;
default:
panic("unexpected mode: %d", new_mode);
break;
}
thread->sched_mode = new_mode;
sched_update_thread_bucket(thread);
}
void
sched_thread_mode_demote(thread_t thread, uint32_t reason)
{
assert(reason & TH_SFLAG_DEMOTED_MASK);
assert((thread->sched_flags & reason) != reason);
if (thread->policy_reset)
return;
if (thread->sched_flags & TH_SFLAG_DEMOTED_MASK) {
thread->sched_flags |= reason;
return;
}
assert(thread->saved_mode == TH_MODE_NONE);
boolean_t removed = thread_run_queue_remove(thread);
thread->sched_flags |= reason;
thread->saved_mode = thread->sched_mode;
sched_set_thread_mode(thread, TH_MODE_TIMESHARE);
thread_recompute_priority(thread);
if (removed)
thread_run_queue_reinsert(thread, SCHED_TAILQ);
}
void
sched_thread_mode_undemote(thread_t thread, uint32_t reason)
{
assert(reason & TH_SFLAG_DEMOTED_MASK);
assert((thread->sched_flags & reason) == reason);
assert(thread->saved_mode != TH_MODE_NONE);
assert(thread->sched_mode == TH_MODE_TIMESHARE);
assert(thread->policy_reset == 0);
thread->sched_flags &= ~reason;
if (thread->sched_flags & TH_SFLAG_DEMOTED_MASK) {
return;
}
boolean_t removed = thread_run_queue_remove(thread);
sched_set_thread_mode(thread, thread->saved_mode);
thread->saved_mode = TH_MODE_NONE;
thread_recompute_priority(thread);
if (removed)
thread_run_queue_reinsert(thread, SCHED_TAILQ);
}