Files
threadx/common_smp/src/tx_thread_preemption_change.c
2021-10-14 00:51:26 +00:00

299 lines
12 KiB
C

/**************************************************************************/
/* */
/* 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_trace.h"
#include "tx_initialize.h"
#include "tx_thread.h"
/**************************************************************************/
/* */
/* FUNCTION RELEASE */
/* */
/* _tx_thread_preemption_change PORTABLE SMP */
/* 6.1 */
/* AUTHOR */
/* */
/* William E. Lamie, Microsoft Corporation */
/* */
/* DESCRIPTION */
/* */
/* This function processes preemption-threshold change requests. The */
/* previous preemption is returned to the caller. If the new request */
/* allows a higher priority thread to execute, preemption takes place */
/* inside of this function. */
/* */
/* INPUT */
/* */
/* thread_ptr Pointer to thread */
/* new_threshold New preemption-threshold */
/* old_threshold Old preemption-threshold */
/* */
/* OUTPUT */
/* */
/* status Service return status */
/* */
/* CALLS */
/* */
/* _tx_thread_smp_rebalance_execute_list Rebalance the execution list */
/* _tx_thread_system_preempt_check Check for preemption */
/* */
/* CALLED BY */
/* */
/* Application Code */
/* */
/* RELEASE HISTORY */
/* */
/* DATE NAME DESCRIPTION */
/* */
/* 09-30-2020 William E. Lamie Initial Version 6.1 */
/* */
/**************************************************************************/
UINT _tx_thread_preemption_change(TX_THREAD *thread_ptr, UINT new_threshold, UINT *old_threshold)
{
TX_INTERRUPT_SAVE_AREA
UINT core_index;
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
ULONG priority_bit;
UINT base_priority;
UINT priority_bit_set;
ULONG priority_map;
UINT next_preempted;
TX_THREAD *preempted_thread;
#if TX_MAX_PRIORITIES > 32
UINT map_index;
#endif
#endif
UINT status;
#ifdef TX_DISABLE_PREEMPTION_THRESHOLD
/* Only allow 0 (disable all preemption) and returning preemption-threshold to the
current thread priority if preemption-threshold is disabled. All other threshold
values are converted to 0. */
if (new_threshold < thread_ptr -> tx_thread_user_priority)
{
/* Is the new threshold zero? */
if (new_threshold != ((UINT) 0))
{
/* Convert the new threshold to disable all preemption, since preemption-threshold is
not supported. */
new_threshold = ((UINT) 0);
}
}
#endif
/* Default status to success. */
status = TX_SUCCESS;
/* Lockout interrupts while the thread is being resumed. */
TX_DISABLE
/* If trace is enabled, insert this event into the trace buffer. */
TX_TRACE_IN_LINE_INSERT(TX_TRACE_THREAD_PREEMPTION_CHANGE, thread_ptr, new_threshold, thread_ptr -> tx_thread_preempt_threshold, thread_ptr -> tx_thread_state, TX_TRACE_THREAD_EVENTS)
/* Log this kernel call. */
TX_EL_THREAD_PREEMPTION_CHANGE_INSERT
/* Determine if the new threshold is greater than the current user priority. */
if (new_threshold > thread_ptr -> tx_thread_user_priority)
{
/* Restore interrupts. */
TX_RESTORE
/* Return error. */
status = TX_THRESH_ERROR;
}
else
{
/* Return the user's preemption-threshold. */
*old_threshold = thread_ptr -> tx_thread_user_preempt_threshold;
/* Setup the new threshold. */
thread_ptr -> tx_thread_user_preempt_threshold = new_threshold;
/* Determine if the new threshold represents a higher priority than the priority inheritance threshold. */
if (new_threshold < thread_ptr -> tx_thread_inherit_priority)
{
/* Update the actual preemption-threshold with the new threshold. */
thread_ptr -> tx_thread_preempt_threshold = new_threshold;
}
else
{
/* Update the actual preemption-threshold with the priority inheritance. */
thread_ptr -> tx_thread_preempt_threshold = thread_ptr -> tx_thread_inherit_priority;
}
/* Determine if the thread is ready and scheduled. */
if (thread_ptr -> tx_thread_state == TX_READY)
{
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
/* Determine if the new threshold is the same as the priority. */
if (thread_ptr -> tx_thread_user_priority == new_threshold)
{
/* Yes, preemption-threshold is being disabled. */
/* Determine if this thread was scheduled with preemption-threshold in force. */
if (_tx_thread_preemption_threshold_list[thread_ptr -> tx_thread_priority] == thread_ptr)
{
/* Clear the entry in the preempted list. */
_tx_thread_preemption_threshold_list[thread_ptr -> tx_thread_priority] = TX_NULL;
#if TX_MAX_PRIORITIES > 32
/* Calculate the index into the bit map array. */
map_index = (thread_ptr -> tx_thread_priority)/((UINT) 32);
#endif
/* Yes, this thread is at the front of the list. Make sure
the preempted bit is cleared for this thread. */
TX_MOD32_BIT_SET(thread_ptr -> tx_thread_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 preempt map has nothing set. */
TX_DIV32_BIT_SET(thread_ptr -> tx_thread_priority, priority_bit)
_tx_thread_preempted_map_active = _tx_thread_preempted_map_active & (~(priority_bit));
}
#endif
}
}
#endif
/* Determine if this thread has global preemption disabled. */
if (thread_ptr == _tx_thread_preemption__threshold_scheduled)
{
/* Clear the global preemption disable flag. */
_tx_thread_preemption__threshold_scheduled = TX_NULL;
#ifndef TX_DISABLE_PREEMPTION_THRESHOLD
/* 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];
/* Pickup the preempted thread. */
_tx_thread_preemption__threshold_scheduled = preempted_thread;
}
#endif
}
/* See if preemption needs to take place. */
#ifdef TX_THREAD_SMP_DEBUG_ENABLE
/* Debug entry. */
_tx_thread_smp_debug_entry_insert(12, 0, thread_ptr);
#endif
/* Pickup the index. */
core_index = TX_SMP_CORE_ID;
/* Call the rebalance routine. This routine maps cores and ready threads. */
_tx_thread_smp_rebalance_execute_list(core_index);
#ifdef TX_THREAD_SMP_DEBUG_ENABLE
/* Debug entry. */
_tx_thread_smp_debug_entry_insert(13, 0, thread_ptr);
#endif
/* Restore interrupts. */
TX_RESTORE
/* Check for preemption. */
_tx_thread_system_preempt_check();
}
else
{
/* Restore interrupts. */
TX_RESTORE
}
}
/* Return completion status. */
return(status);
}