X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/316670eb35587141e969394ae8537d66b9211e80..e8c3f78193f1895ea514044358b93b1add9322f3:/osfmk/kern/priority.c diff --git a/osfmk/kern/priority.c b/osfmk/kern/priority.c index a7fa6ea44..40eb17242 100644 --- a/osfmk/kern/priority.c +++ b/osfmk/kern/priority.c @@ -56,11 +56,11 @@ /* */ /* - * File: clock_prim.c + * File: priority.c * Author: Avadis Tevanian, Jr. * Date: 1986 * - * Clock primitives. + * Priority related scheduler bits. */ #include @@ -75,6 +75,17 @@ #include #include #include +#include + +#ifdef CONFIG_MACH_APPROXIMATE_TIME +#include /* for commpage_update_mach_approximate_time */ +#endif + +#if MONOTONIC +#include +#endif /* MONOTONIC */ + +static void sched_update_thread_bucket(thread_t thread); /* * thread_quantum_expire: @@ -92,18 +103,46 @@ thread_quantum_expire( 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); /* * We bill CPU time to both the individual thread and its task. * - * Because this balance adjustment could potentially attempt to wake this very - * thread, we must credit the ledger before taking the thread lock. The ledger - * pointers are only manipulated by the thread itself at the ast boundary. + * Because this balance adjustment could potentially attempt to wake this + * very thread, we must credit the ledger before taking the thread lock. + * The ledger pointers are only manipulated by the thread itself at the ast + * boundary. + * + * TODO: This fails to account for the time between when the timer was + * armed and when it fired. It should be based on the system_timer and + * running a timer_update operation here. */ - ledger_credit(thread->t_ledger, task_ledgers.cpu_time, thread->current_quantum); - ledger_credit(thread->t_threadledger, thread_ledgers.cpu_time, thread->current_quantum); + 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 /* MONOTONIC */ thread_lock(thread); @@ -111,41 +150,30 @@ thread_quantum_expire( * We've run up until our quantum expiration, and will (potentially) * continue without re-entering the scheduler, so update this now. */ - thread->last_run_time = processor->quantum_end; + processor->last_dispatch = ctime; + thread->last_run_time = ctime; /* * Check for fail-safe trip. */ - if ((thread->sched_mode == TH_MODE_REALTIME || thread->sched_mode == TH_MODE_FIXED) && - !(thread->sched_flags & TH_SFLAG_PROMOTED) && - !(thread->options & TH_OPT_SYSTEM_CRITICAL)) { - uint64_t new_computation; - - new_computation = processor->quantum_end - thread->computation_epoch; - new_computation += thread->computation_metered; - if (new_computation > max_unsafe_computation) { + if ((thread->sched_mode == TH_MODE_REALTIME || thread->sched_mode == TH_MODE_FIXED) && + !(thread->sched_flags & TH_SFLAG_PROMOTED) && + !(thread->sched_flags & TH_SFLAG_PROMOTE_REASON_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); - if (thread->sched_mode == TH_MODE_REALTIME) { - thread->priority = DEPRESSPRI; - } - - thread->saved_mode = thread->sched_mode; - - if (SCHED(supports_timeshare_mode)) { - sched_share_incr(); - thread->sched_mode = TH_MODE_TIMESHARE; - } else { - /* XXX handle fixed->fixed case */ - thread->sched_mode = TH_MODE_FIXED; - } - - thread->safe_release = processor->quantum_end + sched_safe_duration; - thread->sched_flags |= TH_SFLAG_FAILSAFE; + thread->safe_release = ctime + sched_safe_duration; + + sched_thread_mode_demote(thread, TH_SFLAG_FAILSAFE); } } - + /* * Recompute scheduled priority if appropriate. */ @@ -154,19 +182,17 @@ thread_quantum_expire( else SCHED(lightweight_update_priority)(thread); - SCHED(quantum_expire)(thread); - - processor->current_pri = thread->sched_pri; - processor->current_thmode = thread->sched_mode; + if (thread->sched_mode != TH_MODE_REALTIME) + SCHED(quantum_expire)(thread); + + processor_state_update_from_thread(processor, thread); /* * This quantum is up, give this thread another. */ - if (first_timeslice(processor)) - processor->timeslice--; + processor->first_timeslice = FALSE; thread_quantum_init(thread); - thread->last_quantum_refill_time = processor->quantum_end; /* Reload precise timing global policy to thread-local policy */ thread->precise_user_kernel_time = use_precise_user_kernel_time(thread); @@ -176,56 +202,198 @@ thread_quantum_expire( * during privilege transitions, synthesize an event now. */ if (!thread->precise_user_kernel_time) { - timer_switch(PROCESSOR_DATA(processor, current_state), - processor->quantum_end, - PROCESSOR_DATA(processor, current_state)); - timer_switch(PROCESSOR_DATA(processor, thread_timer), - processor->quantum_end, - PROCESSOR_DATA(processor, thread_timer)); + timer_update(PROCESSOR_DATA(processor, current_state), ctime); + timer_update(PROCESSOR_DATA(processor, thread_timer), ctime); + timer_update(&thread->runnable_timer, ctime); } - processor->quantum_end = mach_absolute_time() + thread->current_quantum; - timer_call_enter1(&processor->quantum_timer, thread, - processor->quantum_end, TIMER_CALL_CRITICAL); + + processor->quantum_end = ctime + thread->quantum_remaining; /* - * Context switch check. + * Context switch check + * + * non-urgent flags don't affect kernel threads, so upgrade to urgent + * to ensure that rebalancing and non-recommendation kick in quickly. */ - if ((preempt = csw_check(processor)) != AST_NONE) + + 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); - else { - processor_set_t pset = processor->processor_set; - pset_lock(pset); + /* + * AST_KEVENT does not send an IPI when setting the AST, + * to avoid waiting for the next context switch to propagate the AST, + * the AST is propagated here at quantum expiration. + */ + ast_propagate(thread); + + thread_unlock(thread); + + timer_call_quantum_timer_enter(&processor->quantum_timer, thread, + processor->quantum_end, ctime); + + /* Tell platform layer that we are still running this thread */ + 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 /* CONFIG_SCHED_TIMESHARE_CORE */ + +#if __arm__ || __arm64__ + if (thread->sched_mode == TH_MODE_REALTIME) + sched_consider_recommended_cores(ctime, thread); +#endif /* __arm__ || __arm64__ */ + + KERNEL_DEBUG_CONSTANT(MACHDBG_CODE(DBG_MACH_SCHED, MACH_SCHED_QUANTUM_EXPIRED) | DBG_FUNC_END, preempt, 0, 0, 0, 0); +} + +/* + * sched_set_thread_base_priority: + * + * Set the base priority of the thread + * and reset its scheduled priority. + * + * This is the only path to change base_pri. + * + * Called with the thread locked. + */ +void +sched_set_thread_base_priority(thread_t thread, int priority) +{ + assert(priority >= MINPRI); + uint64_t ctime = 0; - pset_pri_hint(pset, processor, processor->current_pri); - pset_count_hint(pset, processor, SCHED(processor_runq_count)(processor)); + 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); + } - pset_unlock(pset); + /* + * Currently the perfcontrol_attr depends on the base pri of the + * thread. Therefore, we use this function as the hook for the + * perfcontrol callout. + */ + 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_unlock(thread); + thread_recompute_sched_pri(thread, SETPRI_DEFAULT); } -#if defined(CONFIG_SCHED_TRADITIONAL) +/* + * thread_recompute_sched_pri: + * + * Reset the scheduled priority of the thread + * according to its base priority if the + * thread has not been promoted or depressed. + * + * This is the only way to push base_pri changes into sched_pri, + * or to recalculate the appropriate sched_pri after changing + * a promotion or depression. + * + * Called at splsched with the thread locked. + * + * TODO: Add an 'update urgency' flag to avoid urgency callouts on every rwlock operation + */ +void +thread_recompute_sched_pri(thread_t thread, set_sched_pri_options_t options) +{ + uint32_t sched_flags = thread->sched_flags; + sched_mode_t sched_mode = thread->sched_mode; + + int priority = thread->base_pri; + + if (sched_mode == TH_MODE_TIMESHARE) + priority = SCHED(compute_timeshare_priority)(thread); + + if (sched_flags & TH_SFLAG_DEPRESS) { + /* thread_yield_internal overrides kernel mutex promotion */ + priority = DEPRESSPRI; + } else { + /* poll-depress is overridden by mutex promotion and promote-reasons */ + if ((sched_flags & TH_SFLAG_POLLDEPRESS)) { + priority = DEPRESSPRI; + } + + if (sched_flags & TH_SFLAG_PROMOTED) { + priority = MAX(priority, thread->promotion_priority); + + if (sched_mode != TH_MODE_REALTIME) + priority = MIN(priority, MAXPRI_PROMOTE); + } + + if (sched_flags & TH_SFLAG_PROMOTE_REASON_MASK) { + if (sched_flags & TH_SFLAG_RW_PROMOTED) + priority = MAX(priority, MINPRI_RWLOCK); + + if (sched_flags & TH_SFLAG_WAITQ_PROMOTED) + priority = MAX(priority, MINPRI_WAITQ); + + if (sched_flags & TH_SFLAG_EXEC_PROMOTED) + priority = MAX(priority, MINPRI_EXEC); + } + } + + set_sched_pri(thread, priority, options); +} void -sched_traditional_quantum_expire(thread_t thread __unused) +sched_default_quantum_expire(thread_t thread __unused) { - /* - * No special behavior when a timeshare, fixed, or realtime thread - * uses up its entire quantum - */ + /* + * No special behavior when a timeshare, fixed, or realtime thread + * uses up its entire quantum + */ } +#if defined(CONFIG_SCHED_TIMESHARE_CORE) + +/* + * lightweight_update_priority: + * + * Update the scheduled priority for + * a timesharing thread. + * + * Only for use on the current thread. + * + * Called with the thread locked. + */ void lightweight_update_priority(thread_t thread) { + assert(thread->runq == PROCESSOR_NULL); + assert(thread == current_thread()); + if (thread->sched_mode == TH_MODE_TIMESHARE) { - register uint32_t delta; - + int priority; + uint32_t delta; + thread_timer_delta(thread, delta); - + /* * Accumulate timesharing usage only * during contention for processor @@ -233,18 +401,14 @@ lightweight_update_priority(thread_t thread) */ if (thread->pri_shift < INT8_MAX) thread->sched_usage += delta; - + thread->cpu_delta += delta; - - /* - * Adjust the scheduled priority if - * the thread has not been promoted - * and is not depressed. - */ - if ( !(thread->sched_flags & TH_SFLAG_PROMOTED) && - !(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) ) - compute_my_priority(thread); - } + + priority = sched_compute_timeshare_priority(thread); + + if (priority != thread->sched_pri) + thread_recompute_sched_pri(thread, SETPRI_LAZY); + } } /* @@ -268,113 +432,62 @@ static struct shift_data sched_decay_shifts[SCHED_DECAY_TICKS] = { }; /* - * do_priority_computation: + * sched_compute_timeshare_priority: * * Calculate the timesharing priority based upon usage and load. */ -#ifdef CONFIG_EMBEDDED +extern int sched_pri_decay_band_limit; -#define do_priority_computation(thread, pri) \ - MACRO_BEGIN \ - (pri) = (thread)->priority /* start with base priority */ \ - - ((thread)->sched_usage >> (thread)->pri_shift); \ - if ((pri) < MAXPRI_THROTTLE) { \ - if ((thread)->task->max_priority > MAXPRI_THROTTLE) \ - (pri) = MAXPRI_THROTTLE; \ - else \ - if ((pri) < MINPRI_USER) \ - (pri) = MINPRI_USER; \ - } else \ - if ((pri) > MAXPRI_KERNEL) \ - (pri) = MAXPRI_KERNEL; \ - MACRO_END - -#else - -#define do_priority_computation(thread, pri) \ - MACRO_BEGIN \ - (pri) = (thread)->priority /* start with base priority */ \ - - ((thread)->sched_usage >> (thread)->pri_shift); \ - if ((pri) < MINPRI_USER) \ - (pri) = MINPRI_USER; \ - else \ - if ((pri) > MAXPRI_KERNEL) \ - (pri) = MAXPRI_KERNEL; \ - MACRO_END - -#endif /* defined(CONFIG_SCHED_TRADITIONAL) */ - -#endif +#ifdef CONFIG_EMBEDDED -/* - * set_priority: - * - * Set the base priority of the thread - * and reset its scheduled priority. - * - * Called with the thread locked. - */ -void -set_priority( - register thread_t thread, - register int priority) +int +sched_compute_timeshare_priority(thread_t thread) { - thread->priority = priority; - SCHED(compute_priority)(thread, FALSE); -} + int decay_amount = (thread->sched_usage >> thread->pri_shift); + int decay_limit = sched_pri_decay_band_limit; -#if defined(CONFIG_SCHED_TRADITIONAL) + if (thread->base_pri > BASEPRI_FOREGROUND) { + decay_limit += (thread->base_pri - BASEPRI_FOREGROUND); + } -/* - * compute_priority: - * - * Reset the scheduled priority of the thread - * according to its base priority if the - * thread has not been promoted or depressed. - * - * Called with the thread locked. - */ -void -compute_priority( - register thread_t thread, - boolean_t override_depress) -{ - register int priority; + if (decay_amount > decay_limit) { + decay_amount = decay_limit; + } - if ( !(thread->sched_flags & TH_SFLAG_PROMOTED) && - (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) || - override_depress ) ) { - if (thread->sched_mode == TH_MODE_TIMESHARE) - do_priority_computation(thread, priority); - else - priority = thread->priority; + /* start with base priority */ + int priority = thread->base_pri - decay_amount; - set_sched_pri(thread, priority); + 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; } -/* - * compute_my_priority: - * - * Reset the scheduled priority for - * a timesharing thread. - * - * Only for use on the current thread - * if timesharing and not depressed. - * - * Called with the thread locked. - */ -void -compute_my_priority( - register thread_t thread) +#else /* CONFIG_EMBEDDED */ + +int +sched_compute_timeshare_priority(thread_t thread) { - register int priority; + /* start with base priority */ + int priority = thread->base_pri - (thread->sched_usage >> thread->pri_shift); - do_priority_computation(thread, priority); - assert(thread->runq == PROCESSOR_NULL); - thread->sched_pri = priority; + if (priority < MINPRI_USER) + priority = MINPRI_USER; + else if (priority > MAXPRI_KERNEL) + priority = MAXPRI_KERNEL; + + return priority; } +#endif /* CONFIG_EMBEDDED */ + /* * can_update_priority * @@ -401,27 +514,28 @@ can_update_priority( */ void update_priority( - register thread_t thread) + thread_t thread) { - register unsigned ticks; - register uint32_t delta; + uint32_t ticks, delta; ticks = sched_tick - thread->sched_stamp; assert(ticks != 0); + thread->sched_stamp += ticks; - thread->pri_shift = sched_pri_shift; + + /* If requested, accelerate aging of sched_usage */ + if (sched_decay_usage_age_factor > 1) + ticks *= sched_decay_usage_age_factor; /* * Gather cpu usage data. */ thread_timer_delta(thread, delta); if (ticks < SCHED_DECAY_TICKS) { - register struct shift_data *shiftp; - /* - * Accumulate timesharing usage only - * during contention for processor - * resources. + * Accumulate timesharing usage only during contention for processor + * resources. Use the pri_shift from the previous tick window to + * determine if the system was in a contended state. */ if (thread->pri_shift < INT8_MAX) thread->sched_usage += delta; @@ -429,25 +543,20 @@ update_priority( thread->cpu_usage += delta + thread->cpu_delta; thread->cpu_delta = 0; - shiftp = &sched_decay_shifts[ticks]; + 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); + 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_usage >> shiftp->shift1) - - (thread->cpu_usage >> -(shiftp->shift2)); - thread->sched_usage = - (thread->sched_usage >> shiftp->shift1) - - (thread->sched_usage >> -(shiftp->shift2)); - } - } - else { + } else { thread->cpu_usage = thread->cpu_delta = 0; thread->sched_usage = 0; } @@ -455,89 +564,375 @@ update_priority( /* * Check for fail-safe release. */ - if ( (thread->sched_flags & TH_SFLAG_FAILSAFE) && - mach_absolute_time() >= thread->safe_release ) { - if (thread->saved_mode != TH_MODE_TIMESHARE) { - if (thread->saved_mode == TH_MODE_REALTIME) { - thread->priority = BASEPRI_RTQUEUES; - } + if ((thread->sched_flags & TH_SFLAG_FAILSAFE) && + mach_absolute_time() >= thread->safe_release) { + sched_thread_mode_undemote(thread, TH_SFLAG_FAILSAFE); + } + + /* + * Now that the thread's CPU usage has been accumulated and aged + * based on contention of the previous tick window, update the + * pri_shift of the thread to match the current global load/shift + * values. The updated pri_shift would be used to calculate the + * new priority of the thread. + */ + thread->pri_shift = sched_pri_shifts[thread->th_sched_bucket]; + + /* Recompute scheduled priority if appropriate. */ + if (thread->sched_mode == TH_MODE_TIMESHARE) + thread_recompute_sched_pri(thread, SETPRI_LAZY); +} + +#endif /* CONFIG_SCHED_TIMESHARE_CORE */ + + +/* + * TH_BUCKET_RUN is a count of *all* runnable non-idle threads. + * Each other bucket is a count of the runnable non-idle threads + * with that property. + */ +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); +} + +/* TH_RUN & !TH_IDLE controls whether a thread has a run count */ + +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_DEFAULT) + new_bucket = TH_BUCKET_SHARE_FG; + else if (thread->base_pri > BASEPRI_UTILITY) + new_bucket = TH_BUCKET_SHARE_DF; + else if (thread->base_pri > MAXPRI_THROTTLE) + new_bucket = TH_BUCKET_SHARE_UT; + else + new_bucket = TH_BUCKET_SHARE_BG; + break; - thread->sched_mode = thread->saved_mode; - thread->saved_mode = TH_MODE_NONE; + default: + panic("unexpected mode: %d", thread->sched_mode); + break; + } - if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) - sched_share_decr(); + if (old_bucket != new_bucket) { + thread->th_sched_bucket = new_bucket; + thread->pri_shift = sched_pri_shifts[new_bucket]; - if (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)) - set_sched_pri(thread, thread->priority); + if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) { + sched_decr_bucket(old_bucket); + sched_incr_bucket(new_bucket); } + } +} + +/* + * Set the thread's true scheduling mode + * Called with thread mutex and thread locked + * The thread has already been removed from the runqueue. + * + * (saved_mode is handled before this point) + */ +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; - thread->sched_flags &= ~TH_SFLAG_FAILSAFE; + default: + panic("unexpected mode: %d", new_mode); + break; } -#if CONFIG_EMBEDDED - /* Check for pending throttle transitions, and safely switch queues */ - if (thread->sched_flags & TH_SFLAG_PENDING_THROTTLE_MASK) { - boolean_t removed = thread_run_queue_remove(thread); - - if (thread->sched_flags & TH_SFLAG_PENDING_THROTTLE_DEMOTION) { - if (thread->sched_mode == TH_MODE_REALTIME) { - thread->saved_mode = thread->sched_mode; - thread->sched_mode = TH_MODE_TIMESHARE; - - if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) - sched_share_incr(); - } else { - /* - * It's possible that this is a realtime thread that has - * already tripped the failsafe, in which case saved_mode - * is already set correctly. - */ - if (!(thread->sched_flags & TH_SFLAG_FAILSAFE)) { - thread->saved_mode = thread->sched_mode; - } - thread->sched_flags &= ~TH_SFLAG_FAILSAFE; - } - thread->sched_flags |= TH_SFLAG_THROTTLED; - - } else { - if ((thread->sched_mode == TH_MODE_TIMESHARE) - && (thread->saved_mode == TH_MODE_REALTIME)) { - if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) - sched_share_decr(); - } - - thread->sched_mode = thread->saved_mode; - thread->saved_mode = TH_MODE_NONE; - thread->sched_flags &= ~TH_SFLAG_THROTTLED; - } - - thread->sched_flags &= ~(TH_SFLAG_PENDING_THROTTLE_MASK); - - if (removed) - thread_setrun(thread, SCHED_TAILQ); + thread->sched_mode = new_mode; + + sched_update_thread_bucket(thread); +} + +/* + * Demote the true scheduler mode to timeshare (called with the thread locked) + */ +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) { + /* Another demotion reason is already active */ + thread->sched_flags |= reason; + return; } -#endif - /* - * Recompute scheduled priority if appropriate. - */ - if ( (thread->sched_mode == TH_MODE_TIMESHARE) && - !(thread->sched_flags & TH_SFLAG_PROMOTED) && - !(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) ) { - register int new_pri; - - do_priority_computation(thread, new_pri); - if (new_pri != thread->sched_pri) { - boolean_t removed = thread_run_queue_remove(thread); - - thread->sched_pri = new_pri; - if (removed) - thread_setrun(thread, SCHED_TAILQ); - } + 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); +} + +/* + * Un-demote the true scheduler mode back to the saved mode (called with the thread locked) + */ +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) { + /* Another demotion reason is still active */ + return; } - - 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); } -#endif /* CONFIG_SCHED_TRADITIONAL */ +/* + * Promote thread to a specific priority + * + * Promotion must not last past syscall boundary + * Clients must always pair promote and unpromote 1:1 + * + * Called at splsched with thread locked + */ +void +sched_thread_promote_to_pri(thread_t thread, + int priority, + __kdebug_only uintptr_t trace_obj /* already unslid */) +{ + assert((thread->sched_flags & TH_SFLAG_PROMOTED) != TH_SFLAG_PROMOTED); + assert(thread->promotion_priority == 0); + assert(priority <= MAXPRI_PROMOTE); + assert(priority > 0); + + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_PROMOTED), + thread_tid(thread), trace_obj, priority); + + thread->sched_flags |= TH_SFLAG_PROMOTED; + thread->promotion_priority = priority; + + thread_recompute_sched_pri(thread, SETPRI_DEFAULT); +} + + +/* + * Update a pre-existing priority promotion to have a higher priority floor + * Priority can only go up from the previous value + * Update must occur while a promotion is active + * + * Called at splsched with thread locked + */ +void +sched_thread_update_promotion_to_pri(thread_t thread, + int priority, + __kdebug_only uintptr_t trace_obj /* already unslid */) +{ + assert(thread->promotions > 0); + assert((thread->sched_flags & TH_SFLAG_PROMOTED) == TH_SFLAG_PROMOTED); + assert(thread->promotion_priority > 0); + assert(priority <= MAXPRI_PROMOTE); + + if (thread->promotion_priority < priority) { + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_PROMOTED_UPDATE), + thread_tid(thread), trace_obj, priority); + + thread->promotion_priority = priority; + thread_recompute_sched_pri(thread, SETPRI_DEFAULT); + } +} + +/* + * End a priority promotion + * Demotes a thread back to its expected priority without the promotion in place + * + * Called at splsched with thread locked + */ +void +sched_thread_unpromote(thread_t thread, + __kdebug_only uintptr_t trace_obj /* already unslid */) +{ + assert((thread->sched_flags & TH_SFLAG_PROMOTED) == TH_SFLAG_PROMOTED); + assert(thread->promotion_priority > 0); + + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_UNPROMOTED), + thread_tid(thread), trace_obj, 0); + + thread->sched_flags &= ~TH_SFLAG_PROMOTED; + thread->promotion_priority = 0; + + thread_recompute_sched_pri(thread, SETPRI_DEFAULT); +} + +/* called with thread locked */ +void +assert_promotions_invariant(thread_t thread) +{ + if (thread->promotions > 0) + assert((thread->sched_flags & TH_SFLAG_PROMOTED) == TH_SFLAG_PROMOTED); + + if (thread->promotions == 0) + assert((thread->sched_flags & TH_SFLAG_PROMOTED) != TH_SFLAG_PROMOTED); +} + +/* + * Promote thread to have a sched pri floor for a specific reason + * + * Promotion must not last past syscall boundary + * Clients must always pair promote and demote 1:1, + * Handling nesting of the same promote reason is the client's responsibility + * + * Called at splsched with thread locked + */ +void +sched_thread_promote_reason(thread_t thread, + uint32_t reason, + __kdebug_only uintptr_t trace_obj /* already unslid */) +{ + assert(reason & TH_SFLAG_PROMOTE_REASON_MASK); + assert((thread->sched_flags & reason) != reason); + + switch (reason) { + case TH_SFLAG_RW_PROMOTED: + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_RW_PROMOTE), + thread_tid(thread), thread->sched_pri, + thread->base_pri, trace_obj); + break; + case TH_SFLAG_WAITQ_PROMOTED: + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_PROMOTE), + thread_tid(thread), thread->sched_pri, + thread->base_pri, trace_obj); + break; + case TH_SFLAG_EXEC_PROMOTED: + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_EXEC_PROMOTE), + thread_tid(thread), thread->sched_pri, + thread->base_pri, trace_obj); + break; + } + + thread->sched_flags |= reason; + + thread_recompute_sched_pri(thread, SETPRI_DEFAULT); +} + +/* + * End a specific promotion reason + * Demotes a thread back to its expected priority without the promotion in place + * + * Called at splsched with thread locked + */ +void +sched_thread_unpromote_reason(thread_t thread, + uint32_t reason, + __kdebug_only uintptr_t trace_obj /* already unslid */) +{ + assert(reason & TH_SFLAG_PROMOTE_REASON_MASK); + assert((thread->sched_flags & reason) == reason); + + switch (reason) { + case TH_SFLAG_RW_PROMOTED: + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_RW_DEMOTE), + thread_tid(thread), thread->sched_pri, + thread->base_pri, trace_obj); + break; + case TH_SFLAG_WAITQ_PROMOTED: + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_WAITQ_DEMOTE), + thread_tid(thread), thread->sched_pri, + thread->base_pri, trace_obj); + break; + case TH_SFLAG_EXEC_PROMOTED: + KDBG(MACHDBG_CODE(DBG_MACH_SCHED, MACH_EXEC_DEMOTE), + thread_tid(thread), thread->sched_pri, + thread->base_pri, trace_obj); + break; + } + + thread->sched_flags &= ~reason; + + thread_recompute_sched_pri(thread, SETPRI_DEFAULT); +} + +