X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/43866e378188c25dd1e2208016ab3cbeb086ae6c..6d2010ae8f7a6078e10b361c6962983bab233e0f:/osfmk/kern/priority.c?ds=sidebyside diff --git a/osfmk/kern/priority.c b/osfmk/kern/priority.c index 23f5e43f0..74b90dfa8 100644 --- a/osfmk/kern/priority.c +++ b/osfmk/kern/priority.c @@ -1,16 +1,19 @@ /* - * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. + * Copyright (c) 2000-2009 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 @@ -20,7 +23,7 @@ * 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@ @@ -60,14 +63,13 @@ * Clock primitives. */ -#include - #include #include #include #include #include #include +#include #include #include #include @@ -77,6 +79,8 @@ * thread_quantum_expire: * * Recalculate the quantum and priority for a thread. + * + * Called at splsched. */ void @@ -84,78 +88,384 @@ thread_quantum_expire( 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; - 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. + */ + thread->last_run_time = processor->quantum_end; + /* * Check for fail-safe trip. */ - if (!(thread->sched_mode & TH_MODE_TIMESHARE)) { - extern uint64_t max_unsafe_computation; - uint64_t new_computation; + 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 = myprocessor->quantum_end; - new_computation -= thread->computation_epoch; - if (new_computation + thread->computation_metered > - max_unsafe_computation) { - extern uint32_t sched_safe_duration; + 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) { + 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; - thread->safe_mode |= TH_MODE_REALTIME; - thread->sched_mode &= ~TH_MODE_REALTIME; + 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 = sched_tick + sched_safe_duration; - thread->sched_mode |= (TH_MODE_FAILSAFE|TH_MODE_TIMESHARE); - thread->sched_mode &= ~TH_MODE_PREEMPT; + thread->safe_release = processor->quantum_end + sched_safe_duration; + thread->sched_flags |= 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); + + SCHED(quantum_expire)(thread); + + processor->current_pri = thread->sched_pri; + processor->current_thmode = thread->sched_mode; + + /* + * This quantum is up, give this thread another. + */ + if (first_timeslice(processor)) + processor->timeslice--; + + thread_quantum_init(thread); + thread->last_quantum_refill_time = processor->quantum_end; + + processor->quantum_end += thread->current_quantum; + timer_call_enter1(&processor->quantum_timer, + thread, processor->quantum_end, 0); + + /* + * Context switch check. + */ + if ((preempt = csw_check(processor)) != AST_NONE) + ast_on(preempt); + else { + processor_set_t pset = processor->processor_set; + + pset_lock(pset); + + pset_pri_hint(pset, processor, processor->current_pri); + pset_count_hint(pset, processor, SCHED(processor_runq_count)(processor)); + + pset_unlock(pset); + } + + thread_unlock(thread); +} + +#if defined(CONFIG_SCHED_TRADITIONAL) + +void +sched_traditional_quantum_expire(thread_t thread __unused) +{ + /* + * No special behavior when a timeshare, fixed, or realtime thread + * uses up its entire quantum + */ +} +void +lightweight_update_priority(thread_t thread) +{ + if (thread->sched_mode == TH_MODE_TIMESHARE) { + register 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; + /* * Adjust the scheduled priority if * the thread has not been promoted * and is not depressed. */ - if ( !(thread->sched_mode & TH_MODE_PROMOTED) && - !(thread->sched_mode & TH_MODE_ISDEPRESSED) ) + if ( !(thread->sched_flags & TH_SFLAG_PROMOTED) && + !(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK) ) compute_my_priority(thread); + } +} + +/* + * 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} +}; + +/* + * do_priority_computation: + * + * Calculate the timesharing priority based upon usage and load. + */ +#ifdef CONFIG_EMBEDDED + +#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 + +/* + * 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) +{ + thread->priority = priority; + SCHED(compute_priority)(thread, FALSE); +} + +#if defined(CONFIG_SCHED_TRADITIONAL) + +/* + * 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 ( !(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; + + set_sched_pri(thread, 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) +{ + register int priority; + + do_priority_computation(thread, priority); + assert(thread->runq == PROCESSOR_NULL); + thread->sched_pri = 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; + thread->pri_shift = sched_pri_shift; + + /* + * 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. + */ + if (thread->pri_shift < INT8_MAX) + thread->sched_usage += delta; + + 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; } /* - * This quantum is up, give this thread another. + * Check for fail-safe release. */ - if (first_quantum(myprocessor)) - myprocessor->slice_quanta--; + 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; + } - 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->sched_mode = thread->saved_mode; + thread->saved_mode = TH_MODE_NONE; - thread_unlock(thread); + if ((thread->state & (TH_RUN|TH_IDLE)) == TH_RUN) + sched_share_decr(); + + if (!(thread->sched_flags & TH_SFLAG_DEPRESSED_MASK)) + set_sched_pri(thread, thread->priority); + } + + thread->sched_flags &= ~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) && + !(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); - splx(s); + thread->sched_pri = new_pri; + if (removed) + thread_setrun(thread, SCHED_TAILQ); + } + } + + return; } + +#endif /* CONFIG_SCHED_TRADITIONAL */