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/**************************************************************************/
/* */
/* Copyright (c) Microsoft Corporation. All rights reserved. */
/* */
/* This software is licensed under the Microsoft Software License */
/* Terms for Microsoft Azure RTOS. Full text of the license can be */
/* found in the LICENSE file at https://aka.ms/AzureRTOS_EULA */
/* and in the root directory of this software. */
/* */
/**************************************************************************/
/**************************************************************************/
/**************************************************************************/
/** */
/** ThreadX Component */
/** */
/** Thread */
/** */
/**************************************************************************/
/**************************************************************************/
#define TX_SOURCE_CODE
#define TX_THREAD_SMP_SOURCE_CODE
/* Include necessary system files. */
#include "tx_api.h"
#include "tx_thread.h"
#include "tx_timer.h"
#include "tx_trace.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_relinquish PORTABLE SMP */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function determines if there is another higher or equal */
/* priority, non-executing thread that can execute on this processor. */
/* such a thread is found, the calling thread relinquishes control. */
/* Otherwise, this function simply returns. */
/* */
/* INPUT */
/* */
/* None */
/* */
/* OUTPUT */
/* */
/* None */
/* */
/* CALLS */
/* */
/* _tx_thread_smp_rebalance_execute_list Rebalance the execution list */
/* _tx_thread_system_return Return to the system */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 09-30-2020 William E. Lamie Initial Version 6.1 */
/* */
/**************************************************************************/
VOID _tx_thread_relinquish(VOID)
{
TX_INTERRUPT_SAVE_AREA
UINT priority;
TX_THREAD *thread_ptr;
TX_THREAD *head_ptr;
TX_THREAD *tail_ptr;
TX_THREAD *next_thread;
TX_THREAD *previous_thread;
UINT core_index;
UINT rebalance;
UINT mapped_core;
ULONG excluded;
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
UINT base_priority;
UINT priority_bit_set;
UINT next_preempted;
ULONG priority_bit;
ULONG priority_map;
TX_THREAD *preempted_thread;
#if TX_MAX_PRIORITIES > 32
UINT map_index;
#endif
#endif
UINT finished;
/* Default finished to false. */
finished = TX_FALSE;
/* Initialize the rebalance flag to false. */
rebalance = TX_FALSE;
/* Lockout interrupts while thread attempts to relinquish control. */
TX_DISABLE
/* Pickup the index. */
core_index = TX_SMP_CORE_ID;
/* Pickup the current thread pointer. */
thread_ptr = _tx_thread_current_ptr[core_index];
#ifndef TX_NO_TIMER
/* Reset time slice for current thread. */
_tx_timer_time_slice[core_index] = thread_ptr -> tx_thread_new_time_slice;
#endif
#ifdef TX_ENABLE_STACK_CHECKING
/* Check this thread's stack. */
TX_THREAD_STACK_CHECK(thread_ptr)
#endif
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_THREAD_RELINQUISH, &thread_ptr, TX_POINTER_TO_ULONG_CONVERT(thread_ptr -> tx_thread_ready_next), 0, 0, TX_TRACE_THREAD_EVENTS)
/* Log this kernel call. */
TX_EL_THREAD_RELINQUISH_INSERT
/* Pickup the thread's priority. */
priority = thread_ptr -> tx_thread_priority;
#ifdef TX_THREAD_SMP_DEBUG_ENABLE
/* Debug entry. */
_tx_thread_smp_debug_entry_insert(0, 0, thread_ptr);
#endif
/* Pickup the next thread. */
next_thread = thread_ptr -> tx_thread_ready_next;
/* Pickup the head of the list. */
head_ptr = _tx_thread_priority_list[priority];
/* Pickup the list tail. */
tail_ptr = head_ptr -> tx_thread_ready_previous;
/* Determine if this thread is not the tail pointer. */
if (thread_ptr != tail_ptr)
{
/* Not the tail pointer, this thread must be moved to the end of the ready list. */
/* Determine if this thread is at the head of the list. */
if (head_ptr == thread_ptr)
{
/* Simply move the head pointer to put this thread at the end of the ready list at this priority. */
_tx_thread_priority_list[priority] = next_thread;
}
else
{
/* Now we need to remove this thread from its current position and place it at the end of the list. */
/* Pickup the previous thread pointer. */
previous_thread = thread_ptr -> tx_thread_ready_previous;
/* Remove the thread from the ready list. */
next_thread -> tx_thread_ready_previous = previous_thread;
previous_thread -> tx_thread_ready_next = next_thread;
/* Insert the thread at the end of the list. */
tail_ptr -> tx_thread_ready_next = thread_ptr;
head_ptr -> tx_thread_ready_previous = thread_ptr;
thread_ptr -> tx_thread_ready_previous = tail_ptr;
thread_ptr -> tx_thread_ready_next = head_ptr;
}
/* Pickup the mapped core of the relinquishing thread - this can be different from the current core. */
mapped_core = thread_ptr -> tx_thread_smp_core_mapped;
/* Determine if the relinquishing thread is no longer present in the execute list. */
if (thread_ptr != _tx_thread_execute_ptr[mapped_core])
{
/* Yes, the thread is no longer mapped. Set the rebalance flag to determine if there is a new mapping due to moving
this thread to the end of the priority list. */
/* Set the rebalance flag to true. */
rebalance = TX_TRUE;
}
/* Determine if preemption-threshold is in force. */
else if (thread_ptr -> tx_thread_preempt_threshold == priority)
{
/* No preemption-threshold is in force. */
/* Determine if there is a thread at the same priority that isn't currently executing. */
do
{
/* Isolate the exclusion for this core. */
excluded = (next_thread -> tx_thread_smp_cores_excluded >> mapped_core) & ((ULONG) 1);
/* Determine if the next thread has preemption-threshold set or is excluded from running on the
mapped core. */
if ((next_thread -> tx_thread_preempt_threshold < next_thread -> tx_thread_priority) ||
(excluded == ((ULONG) 1)))
{
/* Set the rebalance flag. */
rebalance = TX_TRUE;
/* Get out of the loop. We need to rebalance the list when we detect preemption-threshold. */
break;
}
else
{
/* Is the next thread already in the execute list? */
if (next_thread != _tx_thread_execute_ptr[next_thread -> tx_thread_smp_core_mapped])
{
/* No, we can place this thread in the position the relinquishing thread
was in. */
/* Remember this index in the thread control block. */
next_thread -> tx_thread_smp_core_mapped = mapped_core;
/* Setup the entry in the execution list. */
_tx_thread_execute_ptr[mapped_core] = next_thread;
#ifdef TX_THREAD_SMP_DEBUG_ENABLE
/* Debug entry. */
_tx_thread_smp_debug_entry_insert(1, 0, next_thread);
#endif
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
/* Increment the number of thread relinquishes. */
thread_ptr -> tx_thread_performance_relinquish_count++;
/* Increment the total number of thread relinquish operations. */
_tx_thread_performance_relinquish_count++;
/* No, there is another thread ready to run and will be scheduled upon return. */
_tx_thread_performance_non_idle_return_count++;
#endif
#ifdef TX_ENABLE_STACK_CHECKING
/* Check this thread's stack. */
TX_THREAD_STACK_CHECK(next_thread)
#endif
#ifndef TX_NOT_INTERRUPTABLE
/* Increment the preempt disable flag in order to keep the protection. */
_tx_thread_preempt_disable++;
/* Restore interrupts. */
TX_RESTORE
#endif
/* Transfer control to the system so the scheduler can execute
the next thread. */
_tx_thread_system_return();
#ifdef TX_NOT_INTERRUPTABLE
/* Restore interrupts. */
TX_RESTORE
#endif
/* Set the finished flag. */
finished = TX_TRUE;
}
/* Move to the next thread at this priority. */
next_thread = next_thread -> tx_thread_ready_next;
}
} while ((next_thread != thread_ptr) && (finished == TX_FALSE));
/* Determine if we are finished. */
if (finished == TX_FALSE)
{
/* No other thread is ready at this priority... simply return. */
#ifdef TX_THREAD_SMP_DEBUG_ENABLE
/* Debug entry. */
_tx_thread_smp_debug_entry_insert(1, 0, thread_ptr);
#endif
/* Restore interrupts. */
TX_RESTORE
/* Set the finished flag. */
finished = TX_TRUE;
}
}
else
{
/* Preemption-threshold is in force. */
/* Set the rebalance flag. */
rebalance = TX_TRUE;
}
}
/* Determine if preemption-threshold is in force. */
if (thread_ptr -> tx_thread_preempt_threshold < priority)
{
/* Set the rebalance flag. */
rebalance = TX_TRUE;
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
#if TX_MAX_PRIORITIES > 32
/* Calculate the index into the bit map array. */
map_index = priority/((UINT) 32);
#endif
/* Ensure that this thread's priority is clear in the preempt map. */
TX_MOD32_BIT_SET(priority, priority_bit)
_tx_thread_preempted_maps[MAP_INDEX] = _tx_thread_preempted_maps[MAP_INDEX] & (~(priority_bit));
#if TX_MAX_PRIORITIES > 32
/* Determine if there are any other bits set in this preempt map. */
if (_tx_thread_preempted_maps[MAP_INDEX] == ((ULONG) 0))
{
/* No, clear the active bit to signify this preempted map has nothing set. */
TX_DIV32_BIT_SET(priority, priority_bit)
_tx_thread_preempted_map_active = _tx_thread_preempted_map_active & (~(priority_bit));
}
#endif
/* Clear the entry in the preempted list. */
_tx_thread_preemption_threshold_list[priority] = TX_NULL;
/* Does this thread have preemption-threshold? */
if (_tx_thread_preemption__threshold_scheduled == thread_ptr)
{
/* Yes, set the preempted thread to NULL. */
_tx_thread_preemption__threshold_scheduled = TX_NULL;
}
/* Calculate the first thread with preemption-threshold active. */
#if TX_MAX_PRIORITIES > 32
if (_tx_thread_preempted_map_active != ((ULONG) 0))
#else
if (_tx_thread_preempted_maps[0] != ((ULONG) 0))
#endif
{
#if TX_MAX_PRIORITIES > 32
/* Calculate the index to find the next highest priority thread ready for execution. */
priority_map = _tx_thread_preempted_map_active;
/* Calculate the lowest bit set in the priority map. */
TX_LOWEST_SET_BIT_CALCULATE(priority_map, map_index)
/* Calculate the base priority as well. */
base_priority = map_index * ((UINT) 32);
#else
/* Setup the base priority to zero. */
base_priority = ((UINT) 0);
#endif
/* Setup temporary preempted map. */
priority_map = _tx_thread_preempted_maps[MAP_INDEX];
/* Calculate the lowest bit set in the priority map. */
TX_LOWEST_SET_BIT_CALCULATE(priority_map, priority_bit_set)
/* Move priority bit set into priority bit. */
priority_bit = (ULONG) priority_bit_set;
/* Setup the highest priority preempted thread. */
next_preempted = base_priority + priority_bit;
/* Pickup the previously preempted thread. */
preempted_thread = _tx_thread_preemption_threshold_list[next_preempted];
/* Setup the preempted thread. */
_tx_thread_preemption__threshold_scheduled = preempted_thread;
}
#else
/* Determine if this thread has preemption-threshold disabled. */
if (thread_ptr == _tx_thread_preemption__threshold_scheduled)
{
/* Clear the global preemption disable flag. */
_tx_thread_preemption__threshold_scheduled = TX_NULL;
}
#endif
}
/* Check to see if there is still work to do. */
if (finished == TX_FALSE)
{
#ifdef TX_THREAD_SMP_DEBUG_ENABLE
/* Debug entry. */
_tx_thread_smp_debug_entry_insert(1, 0, thread_ptr);
#endif
/* Determine if we need to rebalance the execute list. */
if (rebalance == TX_TRUE)
{
/* Rebalance the excute list. */
_tx_thread_smp_rebalance_execute_list(core_index);
}
/* Determine if this thread needs to return to the system. */
if (_tx_thread_execute_ptr[core_index] != thread_ptr)
{
#ifdef TX_THREAD_ENABLE_PERFORMANCE_INFO
/* Increment the number of thread relinquishes. */
thread_ptr -> tx_thread_performance_relinquish_count++;
/* Increment the total number of thread relinquish operations. */
_tx_thread_performance_relinquish_count++;
/* Determine if an idle system return is present. */
if (_tx_thread_execute_ptr[core_index] == TX_NULL)
{
/* Yes, increment the return to idle return count. */
_tx_thread_performance_idle_return_count++;
}
else
{
/* No, there is another thread ready to run and will be scheduled upon return. */
_tx_thread_performance_non_idle_return_count++;
}
#endif
#ifdef TX_ENABLE_STACK_CHECKING
/* Pickup new thread pointer. */
thread_ptr = _tx_thread_execute_ptr[core_index];
/* Check this thread's stack. */
TX_THREAD_STACK_CHECK(thread_ptr)
#endif
#ifndef TX_NOT_INTERRUPTABLE
/* Increment the preempt disable flag in order to keep the protection. */
_tx_thread_preempt_disable++;
/* Restore interrupts. */
TX_RESTORE
#endif
/* Transfer control to the system so the scheduler can execute
the next thread. */
_tx_thread_system_return();
#ifdef TX_NOT_INTERRUPTABLE
/* Restore interrupts. */
TX_RESTORE
#endif
}
else
{
/* Restore interrupts. */
TX_RESTORE
}
}
}
|
