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change(freertos): Optimized xTaskRemoveFromEventList()

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This commit optimizes xTaskRemoveFromEventList() by removing the
listLIST_IS_EMPTY() check from single core builds. The scenario of the event
list being empty when the function is called can only occur on multi-core
builds.
This commit is contained in:
Darian Leung
2023-08-01 12:40:01 +02:00
parent 5947314431
commit 1620d97299
1 changed files with 23 additions and 21 deletions
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44
components/freertos/FreeRTOS-Kernel/tasks.c
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@@ -3932,23 +3932,31 @@ BaseType_t xTaskRemoveFromEventList( const List_t * const pxEventList )
} }
#endif /* configNUM_CORES > 1 */ #endif /* configNUM_CORES > 1 */
{ {
/* Before taking the kernel lock, another task/ISR could have already /* The event list is sorted in priority order, so the first in the list can
* emptied the pxEventList. So we insert a check here to see if * be removed as it is known to be the highest priority. Remove the TCB from
* pxEventList is empty before attempting to remove an item from it. */ * the delayed list, and add it to the ready list. */
if( listLIST_IS_EMPTY( pxEventList ) == pdFALSE ) #if ( configNUM_CORES > 1 )
/* Before taking the kernel lock, another task/ISR could have already
* emptied the pxEventList. So we insert a check here to see if
* pxEventList is empty before attempting to remove an item from it. */
if( listLIST_IS_EMPTY( pxEventList ) == pdTRUE )
{
/* The pxEventList was emptied before we entered the critical section,
* Nothing to do except return pdFALSE. */
xReturn = pdFALSE;
}
else
#else /* configNUM_CORES > 1 */
/* If an event is for a queue that is locked then this function will never
* get called - the lock count on the queue will get modified instead. This
* means exclusive access to the event list is guaranteed here.
*
* This function assumes that a check has already been made to ensure that
* pxEventList is not empty. */
#endif /* configNUM_CORES > 1 */
{ {
BaseType_t xCurCoreID = xPortGetCoreID(); BaseType_t xCurCoreID = xPortGetCoreID();
/* The event list is sorted in priority order, so the first in the list can
* be removed as it is known to be the highest priority. Remove the TCB from
* the delayed list, and add it to the ready list.
*
* If an event is for a queue that is locked then this function will never
* get called - the lock count on the queue will get modified instead. This
* means exclusive access to the event list is guaranteed here.
*
* This function assumes that a check has already been made to ensure that
* pxEventList is not empty. */
pxUnblockedTCB = listGET_OWNER_OF_HEAD_ENTRY( pxEventList ); /*lint !e9079 void * is used as this macro is used with timers and co-routines too. Alignment is known to be fine as the type of the pointer stored and retrieved is the same. */ pxUnblockedTCB = listGET_OWNER_OF_HEAD_ENTRY( pxEventList ); /*lint !e9079 void * is used as this macro is used with timers and co-routines too. Alignment is known to be fine as the type of the pointer stored and retrieved is the same. */
configASSERT( pxUnblockedTCB ); configASSERT( pxUnblockedTCB );
( void ) uxListRemove( &( pxUnblockedTCB->xEventListItem ) ); ( void ) uxListRemove( &( pxUnblockedTCB->xEventListItem ) );
@@ -4013,12 +4021,6 @@ BaseType_t xTaskRemoveFromEventList( const List_t * const pxEventList )
xReturn = pdFALSE; xReturn = pdFALSE;
} }
} }
else
{
/* The pxEventList was emptied before we entered the critical section,
* Nothing to do except return pdFALSE. */
xReturn = pdFALSE;
}
} }
#if ( configNUM_CORES > 1 ) #if ( configNUM_CORES > 1 )
/* Release the previously taken kernel lock. */ /* Release the previously taken kernel lock. */
@@ -4133,7 +4135,7 @@ void vTaskRemoveFromUnorderedEventList( ListItem_t * pxEventListItem,
* a context switch is required. This function is called with the * a context switch is required. This function is called with the
* scheduler suspended so xYieldPending is set so the context switch * scheduler suspended so xYieldPending is set so the context switch
* occurs immediately that the scheduler is resumed (unsuspended). */ * occurs immediately that the scheduler is resumed (unsuspended). */
xYieldPending = pdTRUE; xYieldPending[ xCurCoreID ] = pdTRUE;
} }
} }
} }