Fix context switch when time slicing is off (#568)

* Fix context switch when time slicing is off When time slicing is off, context switch should only happen when a task with priority higher than the currently executing one is unblocked. Earlier the code was invoking a context switch even when a task with priority equal the currently executing task was unblocked. This commit fixes the code to only do a context switch when a higher priority task is unblocked. Signed-off-by: Gaurav Aggarwal <[email protected]>
FreeRTOS · Nov 8, 2022 · 1072988 · 1072988
1 parent 44e02bf
commit 1072988
Showing 1 changed file with 8 additions and 4 deletions.
diff --git a/tasks.c b/tasks.c
@@ -2812,10 +2812,14 @@ BaseType_t xTaskIncrementTick( void )
                     #if ( configUSE_PREEMPTION == 1 )
                     {
                         /* Preemption is on, but a context switch should
-                         * only be performed if the unblocked task has a
-                         * priority that is equal to or higher than the
-                         * currently executing task. */
-                        if( pxTCB->uxPriority >= pxCurrentTCB->uxPriority )
+                         * only be performed if the unblocked task's
+                         * priority is higher than the currently executing
+                         * task.
+                         * The case of equal priority tasks sharing
+                         * processing time (which happens when both
+                         * preemption and time slicing are on) is
+                         * handled below.*/
+                        if( pxTCB->uxPriority > pxCurrentTCB->uxPriority )
                         {
                             xSwitchRequired = pdTRUE;
                         }