From 7fe6d60bf08df975c395515074c85976d9e4e3fb Mon Sep 17 00:00:00 2001 From: Sebastian Huber Date: Fri, 15 Jul 2022 09:16:04 +0200 Subject: score: Remove PRIORITY_PSEUDO_ISR thread priority The uniprocessor schedulers had some special case logic for the PRIORITY_PSEUDO_ISR priority. Tasks with a priority of PRIORITY_PSEUDO_ISR were allowed to preempt a not preemptible task. If other higher priority task are made ready while a PRIORITY_PSEUDO_ISR task preempts a not preemptible task, then the other tasks run before the not preemptible task. This made the RTEMS_NO_PREEMPT mode ineffective. Remove the PRIORITY_PSEUDO_ISR special case logic. This simplifies the uniprocessor schedulers. Move the uniprocessor-specific scheduler support to the new header file . Close #2365. --- cpukit/include/rtems/score/priority.h | 7 - cpukit/include/rtems/score/scheduleredfimpl.h | 19 +- cpukit/include/rtems/score/schedulerimpl.h | 65 ------ cpukit/include/rtems/score/schedulerpriorityimpl.h | 30 +-- cpukit/include/rtems/score/schedulersimpleimpl.h | 22 +- cpukit/include/rtems/score/scheduleruniimpl.h | 221 +++++++++++++++++++++ 6 files changed, 242 insertions(+), 122 deletions(-) create mode 100644 cpukit/include/rtems/score/scheduleruniimpl.h (limited to 'cpukit/include/rtems/score') diff --git a/cpukit/include/rtems/score/priority.h b/cpukit/include/rtems/score/priority.h index 568e3c4e3e..6f6cc12bac 100644 --- a/cpukit/include/rtems/score/priority.h +++ b/cpukit/include/rtems/score/priority.h @@ -95,13 +95,6 @@ typedef uint64_t Priority_Control; */ #define PRIORITY_MINIMUM 0 -/** - * @brief The priority value of pseudo-ISR threads. - * - * Examples are the MPCI and timer server threads. - */ -#define PRIORITY_PSEUDO_ISR PRIORITY_MINIMUM - /** * @brief The default lowest (least important) thread priority value. * diff --git a/cpukit/include/rtems/score/scheduleredfimpl.h b/cpukit/include/rtems/score/scheduleredfimpl.h index e0a07a8915..06a35ae95f 100644 --- a/cpukit/include/rtems/score/scheduleredfimpl.h +++ b/cpukit/include/rtems/score/scheduleredfimpl.h @@ -39,7 +39,7 @@ #define _RTEMS_SCORE_SCHEDULEREDFIMPL_H #include -#include +#include #ifdef __cplusplus extern "C" { @@ -216,30 +216,23 @@ RTEMS_INLINE_ROUTINE void _Scheduler_EDF_Extract_body( } /** - * @brief Schedules the next ready thread as the heir. + * @brief Gets the highest priority ready thread of the scheduler. * - * @param scheduler The scheduler instance to schedule the minimum of the context of. - * @param the_thread This parameter is not used. - * @param force_dispatch Indicates whether the current heir is blocked even if it is - * not set as preemptible. + * @param scheduler is the scheduler. */ -RTEMS_INLINE_ROUTINE void _Scheduler_EDF_Schedule_body( - const Scheduler_Control *scheduler, - Thread_Control *the_thread, - bool force_dispatch +RTEMS_INLINE_ROUTINE Thread_Control *_Scheduler_EDF_Get_highest_ready( + const Scheduler_Control *scheduler ) { Scheduler_EDF_Context *context; RBTree_Node *first; Scheduler_EDF_Node *node; - (void) the_thread; - context = _Scheduler_EDF_Get_context( scheduler ); first = _RBTree_Minimum( &context->Ready ); node = RTEMS_CONTAINER_OF( first, Scheduler_EDF_Node, Node ); - _Scheduler_Update_heir( node->Base.owner, force_dispatch ); + return node->Base.owner; } /** @} */ diff --git a/cpukit/include/rtems/score/schedulerimpl.h b/cpukit/include/rtems/score/schedulerimpl.h index 806cb4e145..33070651db 100644 --- a/cpukit/include/rtems/score/schedulerimpl.h +++ b/cpukit/include/rtems/score/schedulerimpl.h @@ -668,40 +668,6 @@ Status_Control _Scheduler_Set_affinity( const cpu_set_t *cpuset ); -/** - * @brief Blocks the thread. - * - * @param scheduler The scheduler instance. - * @param the_thread The thread to block. - * @param node The corresponding scheduler node. - * @param extract Method to extract the thread. - * @param schedule Method for scheduling threads. - */ -RTEMS_INLINE_ROUTINE void _Scheduler_Generic_block( - const Scheduler_Control *scheduler, - Thread_Control *the_thread, - Scheduler_Node *node, - void ( *extract )( - const Scheduler_Control *, - Thread_Control *, - Scheduler_Node * - ), - void ( *schedule )( - const Scheduler_Control *, - Thread_Control *, - bool - ) -) -{ - ( *extract )( scheduler, the_thread, node ); - - /* TODO: flash critical section? */ - - if ( _Thread_Is_heir( the_thread ) ) { - ( *schedule )( scheduler, the_thread, true ); - } -} - /** * @brief Gets the number of processors of the scheduler. * @@ -951,37 +917,6 @@ RTEMS_INLINE_ROUTINE void _Scheduler_Discard_idle_thread( } #endif -/** - * @brief Updates the heir. - * - * @param[in, out] new_heir The new heir. - * @param force_dispatch Indicates whether the dispatch happens also if the - * currently running thread is set as not preemptible. - */ -RTEMS_INLINE_ROUTINE void _Scheduler_Update_heir( - Thread_Control *new_heir, - bool force_dispatch -) -{ - Thread_Control *heir = _Thread_Heir; - - if ( heir != new_heir && ( heir->is_preemptible || force_dispatch ) ) { -#if defined(RTEMS_SMP) - /* - * We need this state only for _Thread_Get_CPU_time_used_locked(). Cannot - * use _Scheduler_Thread_change_state() since THREAD_SCHEDULER_BLOCKED to - * THREAD_SCHEDULER_BLOCKED state changes are illegal for the real SMP - * schedulers. - */ - heir->Scheduler.state = THREAD_SCHEDULER_BLOCKED; - new_heir->Scheduler.state = THREAD_SCHEDULER_SCHEDULED; -#endif - _Thread_Update_CPU_time_used( heir, _Thread_Get_CPU( heir ) ); - _Thread_Heir = new_heir; - _Thread_Dispatch_necessary = true; - } -} - /** * @brief Sets a new scheduler. * diff --git a/cpukit/include/rtems/score/schedulerpriorityimpl.h b/cpukit/include/rtems/score/schedulerpriorityimpl.h index d8d226d6f1..06d2027a45 100644 --- a/cpukit/include/rtems/score/schedulerpriorityimpl.h +++ b/cpukit/include/rtems/score/schedulerpriorityimpl.h @@ -41,7 +41,7 @@ #include #include #include -#include +#include #include #ifdef __cplusplus @@ -231,33 +231,21 @@ RTEMS_INLINE_ROUTINE Chain_Node *_Scheduler_priority_Ready_queue_first( } /** - * @brief Scheduling decision logic. + * @brief Gets the highest priority ready thread of the scheduler. * - * This kernel routine implements scheduling decision logic - * for priority-based scheduling. - * - * @param[in, out] scheduler The scheduler instance. - * @param the_thread This parameter is unused. - * @param force_dispatch Indicates whether the dispatch happens also if - * the currently executing thread is set as not preemptible. + * @param scheduler is the scheduler. */ -RTEMS_INLINE_ROUTINE void _Scheduler_priority_Schedule_body( - const Scheduler_Control *scheduler, - Thread_Control *the_thread, - bool force_dispatch +RTEMS_INLINE_ROUTINE Thread_Control *_Scheduler_priority_Get_highest_ready( + const Scheduler_Control *scheduler ) { Scheduler_priority_Context *context = _Scheduler_priority_Get_context( scheduler ); - Thread_Control *heir = (Thread_Control *) - _Scheduler_priority_Ready_queue_first( - &context->Bit_map, - &context->Ready[ 0 ] - ); - ( void ) the_thread; - - _Scheduler_Update_heir( heir, force_dispatch ); + return (Thread_Control *) _Scheduler_priority_Ready_queue_first( + &context->Bit_map, + &context->Ready[ 0 ] + ); } /** diff --git a/cpukit/include/rtems/score/schedulersimpleimpl.h b/cpukit/include/rtems/score/schedulersimpleimpl.h index 2aaf0fe17e..2293433870 100644 --- a/cpukit/include/rtems/score/schedulersimpleimpl.h +++ b/cpukit/include/rtems/score/schedulersimpleimpl.h @@ -39,7 +39,7 @@ #include #include -#include +#include #ifdef __cplusplus extern "C" { @@ -133,28 +133,18 @@ RTEMS_INLINE_ROUTINE void _Scheduler_simple_Extract( } /** - * @brief Scheduling decision logic. + * @brief Gets the highest priority ready thread of the scheduler. * - * This kernel routine implements scheduling decision logic for the simple scheduler. - * - * @param[in, out] scheduler The scheduler instance. - * @param the_thread This parameter is unused. - * @param force_dispatch Indicates whether the dispatch happens also if - * the currently executing thread is set as not preemptible. + * @param scheduler is the scheduler. */ -RTEMS_INLINE_ROUTINE void _Scheduler_simple_Schedule_body( - const Scheduler_Control *scheduler, - Thread_Control *the_thread, - bool force_dispatch +RTEMS_INLINE_ROUTINE Thread_Control *_Scheduler_simple_Get_highest_ready( + const Scheduler_Control *scheduler ) { Scheduler_simple_Context *context = _Scheduler_simple_Get_context( scheduler ); - Thread_Control *heir = (Thread_Control *) _Chain_First( &context->Ready ); - - ( void ) the_thread; - _Scheduler_Update_heir( heir, force_dispatch ); + return (Thread_Control *) _Chain_First( &context->Ready ); } /** @} */ diff --git a/cpukit/include/rtems/score/scheduleruniimpl.h b/cpukit/include/rtems/score/scheduleruniimpl.h new file mode 100644 index 0000000000..faa719ce45 --- /dev/null +++ b/cpukit/include/rtems/score/scheduleruniimpl.h @@ -0,0 +1,221 @@ +/* SPDX-License-Identifier: BSD-2-Clause */ + +/** + * @file + * + * @ingroup RTEMSScoreScheduler + * + * @brief This header file provides interfaces of the supporting the + * implementation of uniprocessor schedulers. + */ + +/* + * Copyright (C) 2010 Gedare Bloom. + * Copyright (C) 2011 On-Line Applications Research Corporation (OAR). + * Copyright (C) 2014, 2022 embedded brains GmbH + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" + * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE + * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR + * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF + * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS + * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN + * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE + * POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _RTEMS_SCORE_SCHEDULERUNIIMPL_H +#define _RTEMS_SCORE_SCHEDULERUNIIMPL_H + +#include + +#ifdef __cplusplus +extern "C" { +#endif + +/** + * @addtogroup RTEMSScoreScheduler + * + * @{ + */ + +/** + * @brief Updates the heir thread of the processor. + * + * @param[in, out] heir is the current heir thread. + * @param[in, out] new_heir is the new heir thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Update_heir( + Thread_Control *heir, + Thread_Control *new_heir +) +{ + _Assert( heir != new_heir ); +#if defined(RTEMS_SMP) + /* + * We need this state only for _Thread_Get_CPU_time_used_locked(). Cannot + * use _Scheduler_Thread_change_state() since THREAD_SCHEDULER_BLOCKED to + * THREAD_SCHEDULER_BLOCKED state changes are illegal for the real SMP + * schedulers. + */ + heir->Scheduler.state = THREAD_SCHEDULER_BLOCKED; + new_heir->Scheduler.state = THREAD_SCHEDULER_SCHEDULED; +#endif + _Thread_Update_CPU_time_used( heir, _Thread_Get_CPU( heir ) ); + _Thread_Heir = new_heir; + _Thread_Dispatch_necessary = true; +} + +/** + * @brief Updates the heir thread of the processor if the current heir is + * not equal to the new heir thread. + * + * The update takes place even if the current heir thread is not preemptible. + * + * @param[in, out] new_heir is the new heir thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Update_heir_if_necessary( + Thread_Control *new_heir +) +{ + Thread_Control *heir = _Thread_Heir; + + if ( heir != new_heir ) { + _Scheduler_uniprocessor_Update_heir( heir, new_heir ); + } +} + +/** + * @brief Updates the heir thread of the processor if the current heir thread + * is preemptible. + * + * @param[in, out] heir is the current heir thread. + * @param[in, out] new_heir is the new heir thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Update_heir_if_preemptible( + Thread_Control *heir, + Thread_Control *new_heir +) +{ + if ( heir != new_heir && heir->is_preemptible ) { + _Scheduler_uniprocessor_Update_heir( heir, new_heir ); + } +} + +/** + * @brief Blocks the thread. + * + * @param scheduler is the scheduler. + * @param the_thread is the thread to block. + * @param node is the scheduler node of the thread. + * @param extract is the handler to extract the thread. + * @param get_highest_ready is the handler to get the highest ready thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Block( + const Scheduler_Control *scheduler, + Thread_Control *the_thread, + Scheduler_Node *node, + void ( *extract )( + const Scheduler_Control *, + Thread_Control *, + Scheduler_Node * + ), + Thread_Control *( *get_highest_ready )( const Scheduler_Control * ) +) +{ + ( *extract )( scheduler, the_thread, node ); + + /* TODO: flash critical section? */ + + if ( _Thread_Is_heir( the_thread ) ) { + Thread_Control *highest_ready; + + highest_ready = ( *get_highest_ready )( scheduler ); + _Scheduler_uniprocessor_Update_heir( _Thread_Heir, highest_ready ); + } +} + +/** + * @brief Schedule the unblocked thread if it is the highest ready thread. + * + * @param scheduler is the scheduler. + * @param the_thread is the thread. + * @param priority is the priority of the thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Unblock( + const Scheduler_Control *scheduler, + Thread_Control *the_thread, + Priority_Control priority +) +{ + Thread_Control *heir; + + heir = _Thread_Heir; + + /* + * If the thread is more important than the heir, then we have a new heir. + * This may or may not result in a context switch. If the current heir + * thread is preemptible, then we need to do a context switch. + */ + if ( priority < _Thread_Get_priority( heir ) ) { + _Scheduler_uniprocessor_Update_heir_if_preemptible( heir, the_thread ); + } +} + +/** + * @brief Schedules the highest ready thread if the current heir thread of the + * processor is preemptible. + * + * @param scheduler is the scheduler. + * @param get_highest_ready is the handler to get the highest ready thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Schedule( + const Scheduler_Control *scheduler, + Thread_Control *( *get_highest_ready )( const Scheduler_Control * ) +) +{ + Thread_Control *highest_ready; + + highest_ready = ( *get_highest_ready )( scheduler ); + _Scheduler_uniprocessor_Update_heir_if_preemptible( + _Thread_Heir, + highest_ready + ); +} + +/** + * @brief Yields to the highest ready thread. + * + * @param scheduler is the scheduler. + * @param get_highest_ready is the handler to get the highest ready thread. + */ +RTEMS_INLINE_ROUTINE void _Scheduler_uniprocessor_Yield( + const Scheduler_Control *scheduler, + Thread_Control *( *get_highest_ready )( const Scheduler_Control * ) +) +{ + Thread_Control *highest_ready; + + highest_ready = ( *get_highest_ready )( scheduler ); + _Scheduler_uniprocessor_Update_heir_if_necessary( highest_ready ); +} + +/** @} */ + +#ifdef __cplusplus +} +#endif + +#endif /* _RTEMS_SCORE_SCHEDULERUNIIMPL_H */ -- cgit v1.2.3