/*
- * 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
/*
* 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;
- s = splsched();
- thread_lock(thread);
+ 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);
/*
- * Check for fail-safe trip.
+ * 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.
*/
- if (!(thread->sched_mode & TH_MODE_TIMESHARE)) {
- extern uint64_t max_unsafe_computation;
- uint64_t new_computation;
+ ledger_credit(thread->t_ledger, task_ledgers.cpu_time, thread->quantum_remaining);
+ ledger_credit(thread->t_threadledger, thread_ledgers.cpu_time, thread->quantum_remaining);
+#ifdef CONFIG_BANK
+ 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;
+#endif
- 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;
+ ctime = mach_absolute_time();
- if (thread->sched_mode & TH_MODE_REALTIME) {
- thread->priority = DEPRESSPRI;
+#ifdef CONFIG_MACH_APPROXIMATE_TIME
+ commpage_update_mach_approximate_time(ctime);
+#endif
- thread->safe_mode |= TH_MODE_REALTIME;
- thread->sched_mode &= ~TH_MODE_REALTIME;
- }
+ 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;
- thread->safe_release = sched_tick + sched_safe_duration;
- thread->sched_mode |= (TH_MODE_FAILSAFE|TH_MODE_TIMESHARE);
- thread->sched_mode &= ~TH_MODE_PREEMPT;
+ /*
+ * Check for fail-safe trip.
+ */
+ 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);
}
}
-
+
/*
* 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
+ SCHED(lightweight_update_priority)(thread);
+
+ if (thread->sched_mode != TH_MODE_REALTIME)
+ SCHED(quantum_expire)(thread);
+
+ processor->current_pri = thread->sched_pri;
+ processor->current_thmode = thread->sched_mode;
+
+ /* 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);
+
+ /*
+ * 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_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;
+
+ /*
+ * Context switch check.
+ */
+ if ((preempt = csw_check(processor, AST_QUANTUM)) != AST_NONE)
+ ast_on(preempt);
+
+ thread_unlock(thread);
+
+ timer_call_enter1(&processor->quantum_timer, thread,
+ processor->quantum_end, TIMER_CALL_SYS_CRITICAL | TIMER_CALL_LOCAL);
+
+#if defined(CONFIG_SCHED_TIMESHARE_CORE)
+ sched_timeshare_consider_maintenance(ctime);
+#endif /* CONFIG_SCHED_TIMESHARE_CORE */
+
+
+ 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)
+{
+ int old_priority = thread->base_pri;
+ thread->base_pri = priority;
+
+ /* A thread is 'throttled' when its base priority is at or below MAXPRI_THROTTLE */
+ if ((priority > MAXPRI_THROTTLE) && (old_priority <= MAXPRI_THROTTLE)) {
+ sched_set_thread_throttled(thread, FALSE);
+ } else if ((priority <= MAXPRI_THROTTLE) && (old_priority > MAXPRI_THROTTLE)) {
+ sched_set_thread_throttled(thread, TRUE);
+ }
+
+ thread_recompute_sched_pri(thread, FALSE);
+}
+
+/*
+ * 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 standard way to push base_pri changes into sched_pri,
+ * or to recalculate the appropriate sched_pri after clearing
+ * a promotion or depression.
+ *
+ * Called at splsched with the thread locked.
+ */
+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
- if (thread->sched_mode & TH_MODE_TIMESHARE) {
- thread_timer_delta(thread);
- thread->sched_usage += thread->sched_delta;
- thread->sched_delta = 0;
+ 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)
+{
+ /*
+ * 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);
+
+ /*
+ * Accumulate timesharing usage only
+ * during contention for processor
+ * resources.
+ */
+ if (thread->pri_shift < INT8_MAX)
+ thread->sched_usage += delta;
+
+ thread->cpu_delta += delta;
+
+ priority = sched_compute_timeshare_priority(thread);
/*
- * Adjust the scheduled priority if
- * the thread has not been promoted
- * and is not depressed.
+ * Adjust the scheduled priority like thread_recompute_sched_pri,
+ * except with the benefit of knowing the thread is on this core.
*/
- if ( !(thread->sched_mode & TH_MODE_PROMOTED) &&
- !(thread->sched_mode & TH_MODE_ISDEPRESSED) )
- compute_my_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,
+ 0, /* eventually, 'reason' */
+ 0);
+ }
}
+}
+
+/*
+ * 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;
+
+
+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;
+}
+
+
+/*
+ * 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(
+ register thread_t thread)
+{
+ register unsigned ticks;
+ register uint32_t delta;
+
+ ticks = sched_tick - thread->sched_stamp;
+ assert(ticks != 0);
+ thread->sched_stamp += ticks;
+ if (sched_use_combined_fgbg_decay)
+ thread->pri_shift = sched_combined_fgbg_pri_shift;
+ else if (thread->sched_flags & TH_SFLAG_THROTTLED)
+ thread->pri_shift = sched_background_pri_shift;
+ else
+ 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;
/*
- * 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) {
+ register struct shift_data *shiftp;
- 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);
+ /*
+ * Accumulate timesharing usage only
+ * during contention for processor
+ * resources.
+ */
+ if (thread->pri_shift < INT8_MAX)
+ thread->sched_usage += delta;
- thread_unlock(thread);
+ thread->cpu_usage += delta + thread->cpu_delta;
+ thread->cpu_delta = 0;
+
+ 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.
+ * Recompute scheduled priority if appropriate.
*/
- ast_check(myprocessor);
+ if (thread->sched_mode == TH_MODE_TIMESHARE) {
+ int priority = sched_compute_timeshare_priority(thread);
+
+ /*
+ * Adjust the scheduled priority like thread_recompute_sched_pri,
+ * except without setting an AST.
+ */
+ 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,
+ 0, /* eventually, 'reason' */
+ 0);
+
+ if (removed)
+ thread_run_queue_reinsert(thread, SCHED_TAILQ);
+ }
+ }
+
+ return;
+}
+
+#endif /* CONFIG_SCHED_TIMESHARE_CORE */
+
+#if MACH_ASSERT
+/* sched_mode == TH_MODE_TIMESHARE controls whether a thread has a timeshare count when it has a run count */
+
+void sched_share_incr(thread_t thread) {
+ assert((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN);
+ assert(thread->sched_mode == TH_MODE_TIMESHARE);
+ assert(thread->SHARE_COUNT == 0);
+ thread->SHARE_COUNT++;
+ (void)hw_atomic_add(&sched_share_count, 1);
+}
+
+void sched_share_decr(thread_t thread) {
+ assert((thread->state & (TH_RUN|TH_IDLE)) != TH_RUN || thread->sched_mode != TH_MODE_TIMESHARE);
+ assert(thread->SHARE_COUNT == 1);
+ (void)hw_atomic_sub(&sched_share_count, 1);
+ thread->SHARE_COUNT--;
+}
+
+/* TH_SFLAG_THROTTLED controls whether a thread has a background count when it has a run count and a share count */
+
+void sched_background_incr(thread_t thread) {
+ assert((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN);
+ assert(thread->sched_mode == TH_MODE_TIMESHARE);
+ assert((thread->sched_flags & TH_SFLAG_THROTTLED) == TH_SFLAG_THROTTLED);
+
+ assert(thread->BG_COUNT == 0);
+ thread->BG_COUNT++;
+ int val = hw_atomic_add(&sched_background_count, 1);
+ assert(val >= 0);
+
+ /* Always do the background change while holding a share count */
+ assert(thread->SHARE_COUNT == 1);
+}
+
+void sched_background_decr(thread_t thread) {
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN && thread->sched_mode == TH_MODE_TIMESHARE)
+ assert((thread->sched_flags & TH_SFLAG_THROTTLED) != TH_SFLAG_THROTTLED);
+ assert(thread->BG_COUNT == 1);
+ int val = hw_atomic_sub(&sched_background_count, 1);
+ thread->BG_COUNT--;
+ assert(val >= 0);
+ assert(thread->BG_COUNT == 0);
+
+ /* Always do the background change while holding a share count */
+ assert(thread->SHARE_COUNT == 1);
+}
+
+
+void
+assert_thread_sched_count(thread_t thread) {
+ /* Only 0 or 1 are acceptable values */
+ assert(thread->BG_COUNT == 0 || thread->BG_COUNT == 1);
+ assert(thread->SHARE_COUNT == 0 || thread->SHARE_COUNT == 1);
+
+ /* BG is only allowed when you already have a share count */
+ if (thread->BG_COUNT == 1)
+ assert(thread->SHARE_COUNT == 1);
+ if (thread->SHARE_COUNT == 0)
+ assert(thread->BG_COUNT == 0);
+
+ if ((thread->state & (TH_RUN|TH_IDLE)) != TH_RUN ||
+ (thread->sched_mode != TH_MODE_TIMESHARE))
+ assert(thread->SHARE_COUNT == 0);
+
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN &&
+ (thread->sched_mode == TH_MODE_TIMESHARE))
+ assert(thread->SHARE_COUNT == 1);
+
+ if ((thread->state & (TH_RUN|TH_IDLE)) != TH_RUN ||
+ (thread->sched_mode != TH_MODE_TIMESHARE) ||
+ !(thread->sched_flags & TH_SFLAG_THROTTLED))
+ assert(thread->BG_COUNT == 0);
+
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN &&
+ (thread->sched_mode == TH_MODE_TIMESHARE) &&
+ (thread->sched_flags & TH_SFLAG_THROTTLED))
+ assert(thread->BG_COUNT == 1);
+}
+
+#endif /* MACH_ASSERT */
+
+/*
+ * 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_sched_count(thread);
+ assert(thread->runq == PROCESSOR_NULL);
+
+ sched_mode_t old_mode = thread->sched_mode;
+
+ thread->sched_mode = new_mode;
+
+ switch (new_mode) {
+ case TH_MODE_FIXED:
+ case TH_MODE_REALTIME:
+ if (old_mode == TH_MODE_TIMESHARE) {
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) {
+ if (thread->sched_flags & TH_SFLAG_THROTTLED)
+ sched_background_decr(thread);
+
+ sched_share_decr(thread);
+ }
+ }
+ break;
+
+ case TH_MODE_TIMESHARE:
+ if (old_mode != TH_MODE_TIMESHARE) {
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) {
+ sched_share_incr(thread);
+
+ if (thread->sched_flags & TH_SFLAG_THROTTLED)
+ sched_background_incr(thread);
+ }
+ }
+ break;
+
+ default:
+ panic("unexpected mode: %d", new_mode);
+ break;
+ }
+
+ assert_thread_sched_count(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);
+ assert_thread_sched_count(thread);
+
+ 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);
- splx(s);
+ assert_thread_sched_count(thread);
}
+
+/*
+ * 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);
+
+ assert_thread_sched_count(thread);
+
+ 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);
+}
+
+/*
+ * Set the thread to be categorized as 'background'
+ * Called with thread mutex and thread lock held
+ *
+ * TODO: Eventually, 'background' should be a true sched_mode.
+ */
+void
+sched_set_thread_throttled(thread_t thread, boolean_t wants_throttle)
+{
+ if (thread->policy_reset)
+ return;
+
+ assert(((thread->sched_flags & TH_SFLAG_THROTTLED) ? TRUE : FALSE) != wants_throttle);
+
+ assert_thread_sched_count(thread);
+
+ if (wants_throttle) {
+ thread->sched_flags |= TH_SFLAG_THROTTLED;
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN && thread->sched_mode == TH_MODE_TIMESHARE) {
+ sched_background_incr(thread);
+ }
+ } else {
+ thread->sched_flags &= ~TH_SFLAG_THROTTLED;
+ if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN && thread->sched_mode == TH_MODE_TIMESHARE) {
+ sched_background_decr(thread);
+ }
+ }
+
+ assert_thread_sched_count(thread);
+}
+
projects / apple / xnu.git / blobdiff