/*
- * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2000-2010 Apple Inc. All rights reserved.
*
- * @APPLE_LICENSE_HEADER_START@
- *
- * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
- * compliance with the License. Please obtain a copy of the License at
- * http://www.opensource.apple.com/apsl/ and read it before using this
- * file.
+ * compliance with the License. The rights granted to you under the License
+ * may not be used to create, or enable the creation or redistribution of,
+ * unlawful or unlicensed copies of an Apple operating system, or to
+ * circumvent, violate, or enable the circumvention or violation of, any
+ * terms of an Apple operating system software license agreement.
+ *
+ * Please obtain a copy of the License at
+ * http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* Please see the License for the specific language governing rights and
* limitations under the License.
*
- * @APPLE_LICENSE_HEADER_END@
+ * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
/*
* @OSF_COPYRIGHT@
/*
*/
/*
- * File: clock_prim.c
+ * File: priority.c
* Author: Avadis Tevanian, Jr.
* Date: 1986
*
- * Clock primitives.
+ * Priority related scheduler bits.
*/
-#include <cpus.h>
-
#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> /* for commpage_update_mach_approximate_time */
+#endif
+
+#if MONOTONIC
+#include <kern/monotonic.h>
+#endif /* MONOTONIC */
+
+static void sched_update_thread_bucket(thread_t thread);
/*
* thread_quantum_expire:
*
* Recalculate the quantum and priority for a thread.
+ *
+ * Called at splsched.
*/
void
timer_call_param_t p0,
timer_call_param_t p1)
{
- register processor_t myprocessor = p0;
- register thread_t thread = p1;
- spl_t s;
+ 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.
+ *
+ * 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->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 */
- s = splsched();
thread_lock(thread);
+ /*
+ * We've run up until our quantum expiration, and will (potentially)
+ * continue without re-entering the scheduler, so update this now.
+ */
+ processor->last_dispatch = ctime;
+ thread->last_run_time = ctime;
+
/*
* Check for fail-safe trip.
*/
- if (!(thread->sched_mode & TH_MODE_TIMESHARE)) {
- extern uint64_t max_unsafe_computation;
- uint64_t new_computation;
-
- new_computation = myprocessor->quantum_end;
- new_computation -= thread->computation_epoch;
- if (new_computation + thread->computation_metered >
- max_unsafe_computation) {
- extern uint32_t sched_safe_duration;
-
- if (thread->sched_mode & TH_MODE_REALTIME) {
- thread->priority = DEPRESSPRI;
-
- thread->safe_mode |= TH_MODE_REALTIME;
- thread->sched_mode &= ~TH_MODE_REALTIME;
- }
-
- thread->safe_release = sched_tick + sched_safe_duration;
- thread->sched_mode |= (TH_MODE_FAILSAFE|TH_MODE_TIMESHARE);
- thread->sched_mode &= ~TH_MODE_PREEMPT;
+ 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);
+
+ thread->safe_release = ctime + sched_safe_duration;
+
+ sched_thread_mode_demote(thread, TH_SFLAG_FAILSAFE);
}
}
-
+
/*
* Recompute scheduled priority if appropriate.
*/
- if (thread->sched_stamp != sched_tick)
- update_priority(thread);
+ if (SCHED(can_update_priority)(thread))
+ SCHED(update_priority)(thread);
else
- if (thread->sched_mode & TH_MODE_TIMESHARE) {
- thread_timer_delta(thread);
- thread->sched_usage += thread->sched_delta;
- thread->sched_delta = 0;
+ SCHED(lightweight_update_priority)(thread);
+
+ 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.
+ */
+ processor->first_timeslice = FALSE;
+
+ thread_quantum_init(thread);
+
+ /* Reload precise timing global policy to thread-local policy */
+ thread->precise_user_kernel_time = use_precise_user_kernel_time(thread);
+
+ /*
+ * Since non-precise user/kernel time doesn't update the state/thread timer
+ * during privilege transitions, synthesize an event now.
+ */
+ if (!thread->precise_user_kernel_time) {
+ 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 = ctime + thread->quantum_remaining;
+
+ /*
+ * 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.
+ */
+
+ 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_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;
+
+ 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);
+ }
+
+ /*
+ * 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_recompute_sched_pri(thread, SETPRI_DEFAULT);
+}
+
+/*
+ * 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_default_quantum_expire(thread_t thread __unused)
+{
+ /*
+ * 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) {
+ int priority;
+ uint32_t delta;
+
+ thread_timer_delta(thread, delta);
/*
- * Adjust the scheduled priority if
- * the thread has not been promoted
- * and is not depressed.
+ * Accumulate timesharing usage only
+ * during contention for processor
+ * resources.
*/
- if ( !(thread->sched_mode & TH_MODE_PROMOTED) &&
- !(thread->sched_mode & TH_MODE_ISDEPRESSED) )
- compute_my_priority(thread);
+ if (thread->pri_shift < INT8_MAX)
+ thread->sched_usage += delta;
+
+ thread->cpu_delta += delta;
+
+ priority = sched_compute_timeshare_priority(thread);
+
+ if (priority != thread->sched_pri)
+ thread_recompute_sched_pri(thread, SETPRI_LAZY);
}
+}
+
+/*
+ * Define shifts for simulating (5/8) ** n
+ *
+ * Shift structures for holding update shifts. Actual computation
+ * is usage = (usage >> shift1) +/- (usage >> abs(shift2)) where the
+ * +/- is determined by the sign of shift 2.
+ */
+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}
+};
+
+/*
+ * sched_compute_timeshare_priority:
+ *
+ * Calculate the timesharing priority based upon usage and load.
+ */
+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;
+ }
+
+ /* start with base priority */
+ 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 /* CONFIG_EMBEDDED */
+
+int
+sched_compute_timeshare_priority(thread_t thread)
+{
+ /* start with base priority */
+ 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 /* CONFIG_EMBEDDED */
+
+/*
+ * can_update_priority
+ *
+ * Make sure we don't do re-dispatches more frequently than a scheduler tick.
+ *
+ * Called with the thread locked.
+ */
+boolean_t
+can_update_priority(
+ thread_t thread)
+{
+ if (sched_tick == thread->sched_stamp)
+ return (FALSE);
+ else
+ return (TRUE);
+}
+
+/*
+ * update_priority
+ *
+ * Perform housekeeping operations driven by scheduler tick.
+ *
+ * Called with the thread locked.
+ */
+void
+update_priority(
+ thread_t thread)
+{
+ uint32_t ticks, delta;
+
+ ticks = sched_tick - thread->sched_stamp;
+ assert(ticks != 0);
+
+ thread->sched_stamp += ticks;
+
+ /* If requested, accelerate aging of sched_usage */
+ if (sched_decay_usage_age_factor > 1)
+ ticks *= sched_decay_usage_age_factor;
/*
- * This quantum is up, give this thread another.
+ * Gather cpu usage data.
*/
- if (first_quantum(myprocessor))
- myprocessor->slice_quanta--;
+ thread_timer_delta(thread, delta);
+ if (ticks < SCHED_DECAY_TICKS) {
+ /*
+ * 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;
- thread->current_quantum = (thread->sched_mode & TH_MODE_REALTIME)?
- thread->realtime.computation: std_quantum;
- myprocessor->quantum_end += thread->current_quantum;
- timer_call_enter1(&myprocessor->quantum_timer,
- thread, myprocessor->quantum_end);
+ thread->cpu_usage += delta + thread->cpu_delta;
+ thread->cpu_delta = 0;
- thread_unlock(thread);
+ 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;
+ }
+
+ /*
+ * Check for fail-safe release.
+ */
+ if ((thread->sched_flags & TH_SFLAG_FAILSAFE) &&
+ mach_absolute_time() >= thread->safe_release) {
+ sched_thread_mode_undemote(thread, TH_SFLAG_FAILSAFE);
+ }
/*
- * Check for and schedule ast if needed.
+ * 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.
*/
- ast_check(myprocessor);
+ 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);
- splx(s);
+ 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;
+
+ 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);
+ }
+ }
+}
+
+/*
+ * 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;
+
+ default:
+ panic("unexpected mode: %d", new_mode);
+ break;
+ }
+
+ 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;
+ }
+
+ 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;
+ }
+
+ 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);
+}
+
+/*
+ * 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);
+}
+
+
projects / apple / xnu.git / blobdiff