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Diffstat (limited to 'FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/task_pool/DemoTasks/SimpleTaskPoolExamples.c')
| -rw-r--r-- | FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/task_pool/DemoTasks/SimpleTaskPoolExamples.c | 596 |
1 files changed, 596 insertions, 0 deletions
diff --git a/FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/task_pool/DemoTasks/SimpleTaskPoolExamples.c b/FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/task_pool/DemoTasks/SimpleTaskPoolExamples.c new file mode 100644 index 000000000..7b7f0cd2e --- /dev/null +++ b/FreeRTOS-Plus/Demo/FreeRTOS_IoT_Libraries/task_pool/DemoTasks/SimpleTaskPoolExamples.c @@ -0,0 +1,596 @@ +/*
+ * FreeRTOS Kernel V10.2.1
+ * Copyright (C) 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to
+ * use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+ * the Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+ * IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * http://www.FreeRTOS.org
+ * http://aws.amazon.com/freertos
+ *
+ * 1 tab == 4 spaces!
+ */
+
+//_RB_ Add link to docs here.
+
+/* Kernel includes. */
+#include "FreeRTOS.h"
+#include "task.h"
+
+/* Standard includes. */
+#include <stdio.h>
+
+/* IoT SDK includes. */
+#include "iot_taskpool.h"
+
+/* The priority at which that tasks in the task pool (the worker tasks) get
+created. */
+#define tpTASK_POOL_WORKER_PRIORITY 1
+
+/* The number of jobs created in the example functions that create more than
+one job. */
+#define tpJOBS_TO_CREATE 5
+
+/*
+ * Prototypes for the functions that demonstrate the task pool API.
+ * See the implementation of the prvTaskPoolDemoTask() function within this file
+ * for a description of the individual functions. A configASSERT() is hit if
+ * any of the demos encounter any unexpected behaviour.
+ */
+static void prvExample_BasicSingleJob( void );
+static void prvExample_DeferredJobAndCancellingJobs( void );
+static void prvExample_BasicRecyclableJob( void );
+static void prvExample_ReuseRecyclableJobFromLowPriorityTask( void );
+static void prvExample_ReuseRecyclableJobFromHighPriorityTask( void );
+
+/*
+ * Prototypes of the callback functions used in the examples. The callback
+ * simply sends a signal (in the form of a direct task notification) to the
+ * prvTaskPoolDemoTask() task to let the task know that the callback execute.
+ * The handle of the prvTaskPoolDemoTask() task is not accessed directly, but
+ * instead passed into the task pool job as the job's context.
+ */
+static void prvSimpleTaskNotifyCallback( IotTaskPool_t pTaskPool, IotTaskPoolJob_t pJob, void *pUserContext );
+
+/*
+ * The task used to demonstrate the task pool API. This task just loops through
+ * each demo in turn.
+ */
+static void prvTaskPoolDemoTask( void *pvParameters );
+
+/*-----------------------------------------------------------*/
+
+/* Parameters used to create the system task pool - see TBD for more information
+as the task pool used in this example is a slimmed down version of the full
+library - the slimmed down version being intended specifically for FreeRTOS
+kernel use cases. */
+static const IotTaskPoolInfo_t xTaskPoolParameters = {
+ /* Minimum number of threads in a task pool.
+ Note the slimmed down version of the task
+ pool used by this library does not autoscale
+ the number of tasks in the pool so in this
+ case this sets the number of tasks in the
+ pool. */
+ 2,
+ /* Maximum number of threads in a task pool.
+ Note the slimmed down version of the task
+ pool used by this library does not autoscale
+ the number of tasks in the pool so in this
+ case this parameter is just ignored. */
+ 2,
+ /* Stack size for every task pool thread - in
+ bytes, hence multiplying by the number of bytes
+ in a word as configMINIMAL_STACK_SIZE is
+ specified in words. */
+ configMINIMAL_STACK_SIZE * sizeof( portSTACK_TYPE ),
+ /* Priority for every task pool thread. */
+ tpTASK_POOL_WORKER_PRIORITY,
+ };
+
+/*-----------------------------------------------------------*/
+
+void vStartSimpleTaskPoolDemo( void )
+{
+ /* This example uses a single application task, which in turn is used to
+ create and send jobs to task pool tasks. */
+ xTaskCreate( prvTaskPoolDemoTask, /* Function that implements the task. */
+ "PoolDemo", /* Text name for the task - only used for debugging. */
+ configMINIMAL_STACK_SIZE, /* Size of stack (in words, not bytes) to allocate for the task. */
+ NULL, /* Task parameter - not used in this case. */
+ tskIDLE_PRIORITY, /* Task priority, must be between 0 and configMAX_PRIORITIES - 1. */
+ NULL ); /* Used to pass out a handle to the created tsak - not used in this case. */
+}
+/*-----------------------------------------------------------*/
+
+static void prvTaskPoolDemoTask( void *pvParameters )
+{
+IotTaskPoolError_t xResult;
+uint32_t ulLoops = 0;
+
+ /* Remove compiler warnings about unused parameters. */
+ ( void ) pvParameters;
+
+ /* The task pool must be created before it can be used. The system task
+ pool is the task pool managed by the task pool library itself - the storage
+ used by the task pool is provided by the library. */
+ xResult = IotTaskPool_CreateSystemTaskPool( &xTaskPoolParameters );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* Attempting to create the task pool again should then appear to succeed
+ (in case it is initialised by more than one library), but have no effect. */
+ xResult = IotTaskPool_CreateSystemTaskPool( &xTaskPoolParameters );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ for( ;; )
+ {
+ /* Demonstrate the most basic use case where a non persistent job is
+ created and scheduled to run immediately. The task pool worker tasks
+ (in which the job callback function executes) have a priority above the
+ priority of this task so the job's callback executes as soon as it is
+ scheduled. */
+ prvExample_BasicSingleJob();
+
+ /* Demonstrate a job being scheduled to run at some time in the
+ future, and how a job scheduled to run in the future can be cancelled if
+ it has not yet started executing. */
+ prvExample_DeferredJobAndCancellingJobs();
+
+ /* Demonstrate the most basic use of a recyclable job. This is similar
+ to prvExample_BasicSingleJob() but using a recyclable job. Creating a
+ recyclable job will re-use a previously created and now spare job from
+ the task pool's job cache if one is available, or otherwise dynamically
+ create a new job if a spare job is not available in the cache but space
+ remains in the cache. */
+ prvExample_BasicRecyclableJob();
+
+ /* Demonstrate multiple recyclable jobs being created, used, and then
+ re-used. In this the task pool worker tasks (in which the job callback
+ functions execute) have a priority above the priority of this task so
+ the job's callback functions execute as soon as they are scheduled. */
+ prvExample_ReuseRecyclableJobFromLowPriorityTask();
+
+ /* Again demonstrate multiple recyclable jobs being used, but this time
+ the priority of the task pool worker tasks (in which the job callback
+ functions execute) are lower than the priority of this task so the job's
+ callback functions don't execute until this task enteres the blocked
+ state. */
+ prvExample_ReuseRecyclableJobFromHighPriorityTask();
+
+ ulLoops++;
+ if( ( ulLoops % 10UL ) == 0 )
+ {
+ printf( "prvTaskPoolDemoTask() performed %u iterations without hitting an assert.\r\n", ulLoops );
+ fflush( stdout );
+ }
+ }
+}
+/*-----------------------------------------------------------*/
+
+static void prvSimpleTaskNotifyCallback( IotTaskPool_t pTaskPool, IotTaskPoolJob_t pJob, void *pUserContext )
+{
+TaskHandle_t xTaskToNotify = ( TaskHandle_t ) pUserContext;
+
+ /* Remove warnings about unused parameters. */
+ ( void ) pTaskPool;
+ ( void ) pJob;
+
+ /* Notify the task that created this job. */
+ xTaskNotifyGive( xTaskToNotify );
+}
+/*-----------------------------------------------------------*/
+
+static void prvExample_BasicSingleJob( void )
+{
+IotTaskPoolJobStorage_t xJobStorage;
+IotTaskPoolJob_t xJob;
+IotTaskPoolError_t xResult;
+uint32_t ulReturn;
+const uint32_t ulNoFlags = 0UL;
+const TickType_t xNoDelay = ( TickType_t ) 0;
+size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
+IotTaskPoolJobStatus_t xJobStatus;
+
+ /* Don't expect any notifications to be pending yet. */
+ configASSERT( ulTaskNotifyTake( pdTRUE, 0 ) == 0 );
+
+ /* Create and schedule a job using the handle of this task as the job's
+ context and the function that sends a notification to the task handle as
+ the jobs callback function. This is not a recyclable job so the storage
+ required to hold information about the job is provided by this task - in
+ this case the storage is on the stack of this task so no memory is allocated
+ dynamically but the stack frame must remain in scope for the lifetime of
+ the job. */
+ xResult = IotTaskPool_CreateJob( prvSimpleTaskNotifyCallback, /* Callback function. */
+ ( void * ) xTaskGetCurrentTaskHandle(), /* Job context. */
+ &xJobStorage,
+ &xJob );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* The job has been created but not scheduled so is now ready. */
+ IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
+
+ /* This is not a persistent (recyclable) job and its storage is on the
+ stack of this function, so the amount of heap space available should not
+ have chanced since entering this function. */
+ configASSERT( xFreeHeapBeforeCreatingJob == xPortGetFreeHeapSize() );
+
+ /* In the full task pool implementation the first parameter is used to
+ pass the handle of the task pool to schedule. The lean task pool
+ implementation used in this demo only supports a single task pool, which
+ is created internally within the library, so the first parameter is NULL. */
+ xResult = IotTaskPool_Schedule( NULL, xJob, ulNoFlags );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* Look for the notification coming from the job's callback function. The
+ priority of the task pool worker task that executes the callback is higher
+ than the priority of this task so a block time is not needed - the task pool
+ worker task pre-empts this task and sends the notification (from the job's
+ callback) as soon as the job is scheduled. */
+ ulReturn = ulTaskNotifyTake( pdTRUE, xNoDelay );
+ configASSERT( ulReturn );
+
+ /* The job's callback has executed so the job has now completed. */
+ IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
+}
+/*-----------------------------------------------------------*/
+
+static void prvExample_DeferredJobAndCancellingJobs( void )
+{
+IotTaskPoolJobStorage_t xJobStorage;
+IotTaskPoolJob_t xJob;
+IotTaskPoolError_t xResult;
+uint32_t ulReturn;
+const uint32_t ulShortDelay_ms = 100UL;
+const TickType_t xNoDelay = ( TickType_t ) 0, xAllowableMargin = ( TickType_t ) 5; /* Large margin for Windows port, which is not real time. */
+TickType_t xTimeBefore, xElapsedTime, xShortDelay_ticks;
+size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
+IotTaskPoolJobStatus_t xJobStatus;
+
+ /* Don't expect any notifications to be pending yet. */
+ configASSERT( ulTaskNotifyTake( pdTRUE, 0 ) == 0 );
+
+ /* Create a job using the handle of this task as the job's context and the
+ function that sends a notification to the task handle as the jobs callback
+ function. The job is created using storage allocated on the stack of this
+ function - so no memory is allocated. */
+ xResult = IotTaskPool_CreateJob( prvSimpleTaskNotifyCallback, /* Callback function. */
+ ( void * ) xTaskGetCurrentTaskHandle(), /* Job context. */
+ &xJobStorage,
+ &xJob );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* The job has been created but not scheduled so is now ready. */
+ IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
+
+ /* This is not a persistent (recyclable) job and its storage is on the
+ stack of this function, so the amount of heap space available should not
+ have chanced since entering this function. */
+ configASSERT( xFreeHeapBeforeCreatingJob == xPortGetFreeHeapSize() );
+
+ /* Schedule the job to run its callback in xShortDelay_ms milliseconds time.
+ In the full task pool implementation the first parameter is used to pass the
+ handle of the task pool to schedule. The lean task pool implementation used
+ in this demo only supports a single task pool, which is created internally
+ within the library, so the first parameter is NULL. */
+ xResult = IotTaskPool_ScheduleDeferred( NULL, xJob, ulShortDelay_ms );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* The scheduled job should not have executed yet, so don't expect any
+ notifications and expect the job's status to be 'deferred'. */
+ ulReturn = ulTaskNotifyTake( pdTRUE, xNoDelay );
+ configASSERT( ulReturn == 0 );
+ IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_DEFERRED );
+
+ /* As the job has not yet been executed it can be stopped. */
+ xResult = IotTaskPool_TryCancel( NULL, xJob, &xJobStatus );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+ IotTaskPool_GetStatus( NULL, xJob, &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_CANCELED );
+
+ /* Schedule the job again, and this time wait until its callback is
+ executed (the callback function sends a notification to this task) to see
+ that it executes at the right time. */
+ xTimeBefore = xTaskGetTickCount();
+ xResult = IotTaskPool_ScheduleDeferred( NULL, xJob, ulShortDelay_ms );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* Wait twice the deferred execution time to ensure the callback is executed
+ before the call below times out. */
+ ulReturn = ulTaskNotifyTake( pdTRUE, pdMS_TO_TICKS( ulShortDelay_ms * 2UL ) );
+ xElapsedTime = xTaskGetTickCount() - xTimeBefore;
+
+ /* A single notification should not have been received... */
+ configASSERT( ulReturn == 1 );
+
+ /* ...and the time since scheduling the job should be greater than or
+ equal to the deferred execution time - which is converted to ticks for
+ comparison. */
+ xShortDelay_ticks = pdMS_TO_TICKS( ulShortDelay_ms );
+ configASSERT( ( xElapsedTime >= xShortDelay_ticks ) && ( xElapsedTime < ( xShortDelay_ticks + xAllowableMargin ) ) );
+}
+/*-----------------------------------------------------------*/
+
+static void prvExample_BasicRecyclableJob( void )
+{
+IotTaskPoolJob_t xJob;
+IotTaskPoolError_t xResult;
+uint32_t ulReturn;
+const uint32_t ulNoFlags = 0UL;
+const TickType_t xNoDelay = ( TickType_t ) 0;
+size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
+
+ /* Don't expect any notifications to be pending yet. */
+ configASSERT( ulTaskNotifyTake( pdTRUE, 0 ) == 0 );
+
+ /* Create and schedule a job using the handle of this task as the job's
+ context and the function that sends a notification to the task handle as
+ the jobs callback function. The job is created as a recyclable job and in
+ this case the memory used to hold the job status is allocated inside the
+ create function. As the job is persistent it can be used multiple times,
+ as demonstrated in other examples within this demo. In the full task pool
+ implementation the first parameter is used to pass the handle of the task
+ pool this recyclable job is to be associated with. In the lean
+ implementation of the task pool used by this demo there is only one task
+ pool (the system task pool created within the task pool library) so the
+ first parameter is NULL. */
+ xResult = IotTaskPool_CreateRecyclableJob( NULL,
+ prvSimpleTaskNotifyCallback,
+ (void * ) xTaskGetCurrentTaskHandle(),
+ &xJob );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* This recyclable job is persistent, and in this case created dynamically,
+ so expect there to be less heap space then when entering the function. */
+ configASSERT( xPortGetFreeHeapSize() < xFreeHeapBeforeCreatingJob );
+
+ /* In the full task pool implementation the first parameter is used to
+ pass the handle of the task pool to schedule. The lean task pool
+ implementation used in this demo only supports a single task pool, which
+ is created internally within the library, so the first parameter is NULL. */
+ xResult = IotTaskPool_Schedule( NULL, xJob, ulNoFlags );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* Look for the notification coming from the job's callback function. The
+ priority of the task pool worker task that executes the callback is higher
+ than the priority of this task so a block time is not needed - the task pool
+ worker task pre-empts this task and sends the notification (from the job's
+ callback) as soon as the job is scheduled. */
+ ulReturn = ulTaskNotifyTake( pdTRUE, xNoDelay );
+ configASSERT( ulReturn );
+
+ /* Clean up recyclable job. In the full implementation of the task pool
+ the first parameter is used to pass a handle to the task pool the job is
+ associated with. In the lean implementation of the task pool used by this
+ demo there is only one task pool (the system task pool created in the
+ task pool library itself) so the first parameter is NULL. */
+ IotTaskPool_DestroyRecyclableJob( NULL, xJob );
+
+ /* Once the job has been deleted the memory used to hold the job is
+ returned, so the available heap should be exactly as when entering this
+ function. */
+ configASSERT( xPortGetFreeHeapSize() == xFreeHeapBeforeCreatingJob );
+}
+/*-----------------------------------------------------------*/
+
+static void prvExample_ReuseRecyclableJobFromLowPriorityTask( void )
+{
+IotTaskPoolError_t xResult;
+uint32_t x, xIndex, ulNotificationValue;
+const uint32_t ulNoFlags = 0UL;
+IotTaskPoolJob_t xJobs[ tpJOBS_TO_CREATE ];
+size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
+IotTaskPoolJobStatus_t xJobStatus;
+
+ /* Don't expect any notifications to be pending yet. */
+ configASSERT( ulTaskNotifyTake( pdTRUE, 0 ) == 0 );
+
+ /* Create tpJOBS_TO_CREATE jobs using the handle of this task as the job's
+ context and the function that sends a notification to the task handle as
+ the jobs callback function. The jobs are created as a recyclable job and
+ in this case the memory to store the job information is allocated within
+ the create function as at this time there are no recyclable jobs in the
+ task pool jobs cache. As the jobs are persistent they can be used multiple
+ times. In the full task pool implementation the first parameter is used to
+ pass the handle of the task pool this recyclable job is to be associated
+ with. In the lean implementation of the task pool used by this demo there
+ is only one task pool (the system task pool created within the task pool
+ library) so the first parameter is NULL. */
+ for( x = 0; x < tpJOBS_TO_CREATE; x++ )
+ {
+ xResult = IotTaskPool_CreateRecyclableJob( NULL,
+ prvSimpleTaskNotifyCallback,
+ (void * ) xTaskGetCurrentTaskHandle(),
+ &( xJobs[ x ] ) );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* The job has been created but not scheduled so is now ready. */
+ IotTaskPool_GetStatus( NULL, xJobs[ x ], &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_READY );
+ }
+
+ /* Demonstrate that the jobs can be recycled by performing twice the number
+ of iterations of scheduling jobs than there actually are created jobs. This
+ works because the task pool task priorities are above the priority of this
+ task, so the tasks that run the jobs pre-empt this task as soon as a job is
+ ready. */
+ for( x = 0; x < ( tpJOBS_TO_CREATE * 2UL ); x++ )
+ {
+ /* Make sure array index does not go out of bounds. */
+ xIndex = x % tpJOBS_TO_CREATE;
+
+ xResult = IotTaskPool_Schedule( NULL, xJobs[ xIndex ], ulNoFlags );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* The priority of the task pool task(s) is higher than the priority
+ of this task, so the job's callback function should have already
+ executed, sending a notification to this task, and incrementing this
+ task's notification value. */
+ xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
+ 0UL, /* Don't clear any bits on exit. */
+ &ulNotificationValue, /* Obtain the notification value. */
+ 0UL ); /* No block time, return immediately. */
+ configASSERT( ulNotificationValue == ( x + 1 ) );
+
+ /* The job's callback has executed so the job is now completed. */
+ IotTaskPool_GetStatus( NULL, xJobs[ xIndex ], &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_COMPLETED );
+
+ /* To leave the list of jobs empty we can stop re-creating jobs half
+ way through iterations of this loop. */
+ if( x < tpJOBS_TO_CREATE )
+ {
+ /* Recycle the job so it can be used again. In the full task pool
+ implementation the first parameter is used to pass the handle of the
+ task pool this job will be associated with. In this lean task pool
+ implementation only the system task pool exists (the task pool created
+ internally to the task pool library) so the first parameter is just
+ passed as NULL. *//*_RB_ Why not recycle it automatically? */
+ IotTaskPool_RecycleJob( NULL, xJobs[ xIndex ] );
+ xResult = IotTaskPool_CreateRecyclableJob( NULL,
+ prvSimpleTaskNotifyCallback,
+ (void * ) xTaskGetCurrentTaskHandle(),
+ &( xJobs[ xIndex ] ) );
+ }
+ }
+
+ /* Clear all the notification value bits again. */
+ xTaskNotifyWait( portMAX_DELAY, /* Clear all bits on entry - portMAX_DELAY is used as it is a portable way of having all bits set. */
+ 0UL, /* Don't clear any bits on exit. */
+ NULL, /* Don't need the notification value this time. */
+ 0UL ); /* No block time, return immediately. */
+ configASSERT( ulTaskNotifyTake( pdTRUE, 0 ) == 0 );
+
+ /* Clean up all the recyclable job. In the full implementation of the task
+ pool the first parameter is used to pass a handle to the task pool the job
+ is associated with. In the lean implementation of the task pool used by
+ this demo there is only one task pool (the system task pool created in the
+ task pool library itself) so the first parameter is NULL. */
+ for( x = 0; x < tpJOBS_TO_CREATE; x++ )
+ {
+ xResult = IotTaskPool_DestroyRecyclableJob( NULL, xJobs[ x ] );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+ }
+
+ /* Once the job has been deleted the memory used to hold the job is
+ returned, so the available heap should be exactly as when entering this
+ function. */
+ configASSERT( xPortGetFreeHeapSize() == xFreeHeapBeforeCreatingJob );
+}
+/*-----------------------------------------------------------*/
+
+static void prvExample_ReuseRecyclableJobFromHighPriorityTask( void )
+{
+IotTaskPoolError_t xResult;
+uint32_t x, ulNotificationValue;
+const uint32_t ulNoFlags = 0UL;
+IotTaskPoolJob_t xJobs[ tpJOBS_TO_CREATE ];
+IotTaskPoolJobStorage_t xJobStorage[ tpJOBS_TO_CREATE ];
+size_t xFreeHeapBeforeCreatingJob = xPortGetFreeHeapSize();
+TickType_t xShortDelay = pdMS_TO_TICKS( 150 );
+IotTaskPoolJobStatus_t xJobStatus;
+
+ /* Don't expect any notifications to be pending yet. */
+ configASSERT( ulTaskNotifyTake( pdTRUE, 0 ) == 0 );
+
+ /* prvExample_ReuseRecyclableJobFromLowPriorityTask() executes in a task
+ that has a lower [task] priority than the task pool's worker tasks.
+ Therefore a talk pool worker preempts the task that calls
+ prvExample_ReuseRecyclableJobFromHighPriorityTask() as soon as the job is
+ scheduled. prvExample_ReuseRecyclableJobFromHighPriorityTask() reverses the
+ priorities - prvExample_ReuseRecyclableJobFromHighPriorityTask() raises its
+ priority to above the task pool's worker tasks, so the worker tasks do not
+ execute until the calling task enters the blocked state. First raise the
+ priority - passing NULL means raise the priority of the calling task. */
+ vTaskPrioritySet( NULL, tpTASK_POOL_WORKER_PRIORITY + 1 );
+
+ /* Create tpJOBS_TO_CREATE jobs using the handle of this task as the job's
+ context and the function that sends a notification to the task handle as
+ the jobs callback function. */
+ for( x = 0; x < tpJOBS_TO_CREATE; x++ )
+ {
+ xResult = IotTaskPool_CreateJob( prvSimpleTaskNotifyCallback, /* Callback function. */
+ ( void * ) xTaskGetCurrentTaskHandle(), /* Job context. */
+ &( xJobStorage[ x ] ),
+ &( xJobs[ x ] ) );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* This is not a persistent (recyclable) job and its storage is on the
+ stack of this function, so the amount of heap space available should not
+ have chanced since entering this function. */
+ configASSERT( xFreeHeapBeforeCreatingJob == xPortGetFreeHeapSize() );
+ }
+
+ for( x = 0; x < tpJOBS_TO_CREATE; x++ )
+ {
+ /* Schedule the next job. */
+ xResult = IotTaskPool_Schedule( NULL, xJobs[ x ], ulNoFlags );
+ configASSERT( xResult == IOT_TASKPOOL_SUCCESS );
+
+ /* Although scheduled, the job's callback has not executed, so the job
+ reports itself as scheduled. */
+ IotTaskPool_GetStatus( NULL, xJobs[ x ], &xJobStatus );
+ configASSERT( xJobStatus == IOT_TASKPOOL_STATUS_SCHEDULED );
+
+ /* The priority of the task pool task(s) is lower than the priority
+ of this task, so the job's callback function should not have executed
+ yes, so don't expect the notification value for this task to have
+ changed. */
+ xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
+ 0UL, /* Don't clear any bits on exit. */
+ &ulNotificationValue, /* Obtain the notification value. */
+ 0UL ); /* No block time, return immediately. */
+ configASSERT( ulNotificationValue == 0 );
+ }
+
+ /* At this point there are tpJOBS_TO_CREATE scheduled, but none have executed
+ their callbacks because the priority of this task is higher than the
+ priority of the task pool worker threads. When this task blocks to wait for
+ a notification a worker thread will be able to executes - but as soon as its
+ callback function sends a notification to this task this task will
+ preempt it (because it has a higher priority) so this task only expects to
+ receive one notification at a time. */
+ for( x = 0; x < tpJOBS_TO_CREATE; x++ )
+ {
+ xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
+ 0UL, /* Don't clear any bits on exit. */
+ &ulNotificationValue, /* Obtain the notification value. */
+ xShortDelay ); /* Short delay to allow a task pool worker to execute. */
+ configASSERT( ulNotificationValue == ( x + 1 ) );
+ }
+
+ /* All the scheduled jobs have now executed, so waiting for another
+ notification should timeout without the notification value changing. */
+ xTaskNotifyWait( 0UL, /* Don't clear any bits on entry. */
+ 0UL, /* Don't clear any bits on exit. */
+ &ulNotificationValue, /* Obtain the notification value. */
+ xShortDelay ); /* Short delay to allow a task pool worker to execute. */
+ configASSERT( ulNotificationValue == x );
+
+ /* Reset the priority of this task and clear the notifications ready for the
+ next example. */
+ vTaskPrioritySet( NULL, tskIDLE_PRIORITY );
+ xTaskNotifyWait( portMAX_DELAY, /* Clear all bits on entry - portMAX_DELAY is used as it is a portable way of having all bits set. */
+ 0UL, /* Don't clear any bits on exit. */
+ NULL, /* Don't need the notification value this time. */
+ 0UL ); /* No block time, return immediately. */
+}
+/*-----------------------------------------------------------*/
+
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