maximum number of Mutex

fadillrezha wrote on Monday, February 03, 2014:

Hi all,

I’m sorry for this trivial question. I am using STM32f407 with STM32 standard peripheral drivers and Keil as development environment.I am currently having a weird problem related to mutex.

I am working based on FreeRTOS and LwIP project provided by ST in
http://www.st.com/web/en/catalog/tools/FM147/CL1794/SC961/SS1743/PF257896?s_searchtype=keyword.

At first I didn’t have any problem, but when I need to add mutexes I found a problem where it seems like there are limit to number of mutex that I can create.

I simply create a mutex, both recursive (xSemaphoreCreateRecursiveMutex)and not(xSemaphoreCreateMutex), and when the number of mutex created is more than a certain number, my code behaves unexpectedly although the mutex is not used anywhere yet. But when I deleted the creation line of one of the mutexes, my code works well. So if I want to make a new mutex after I reach mutex threshold number, I have to delete another mutex, and I conclude that there is a maximum number of mutex that I can create, although I am not sure yet.

I have researched for similar case like mine but can’t seem to find one on the internet. If anyone here can confirm about this problem I would really appreciate it. And I wonder what is the physical resource on STM32F/cortex m-4 that is used when a mutex is created?

Thanks.

richard_damon wrote on Monday, February 03, 2014:

Sounds like you are running out of heap memory to create the mutexs. Are you checking the handle to make sure it isn’t zero? There is a hook you can define to call a function when you get a heap allocation error which is good for debugging.

fadillrezha wrote on Monday, February 03, 2014:

You are right! This is the answer that I’ve been looking for. I failed to recognize the fact that RTOS kernel allocates RAM each time a task, queue, mutex, software timer or semaphore is created.

I simply had to increase the configTOTAL_HEAP_SIZE to solve this problem.

Regards.

I face the exact same problem.

I’m moving a very large project from Keil to CUBEIDE and started to using freeRTOS + CMSIS

I’m currently having a problem with the system falling on Asserts.

I noticed when I using to many Mutexs it fails (I ran a side project which tries how much can be Mutexs can be used).

I tried resizing the heep but it does not help

Can anyone please advise?

STM32F413VGT

up to 1.5 Mbytes of Flash memory, 320 Kbytes of SRAM

FreeRTOS_V1


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#ifndef FREERTOS_CONFIG_H
#define FREERTOS_CONFIG_H

/*-----------------------------------------------------------
 * Application specific definitions.
 *
 * These definitions should be adjusted for your particular hardware and
 * application requirements.
 *
 * These parameters and more are described within the 'configuration' section of the
 * FreeRTOS API documentation available on the FreeRTOS.org web site.
 *
 * See http://www.freertos.org/a00110.html
 *----------------------------------------------------------*/

/* USER CODE BEGIN Includes */
/* Section where include file can be added */
/* USER CODE END Includes */

/* Ensure definitions are only used by the compiler, and not by the assembler. */
#if defined(__ICCARM__) || defined(__CC_ARM) || defined(__GNUC__)
  #include <stdint.h>
  extern uint32_t SystemCoreClock;
  void xPortSysTickHandler(void);
#endif
#define configENABLE_FPU                         0
#define configENABLE_MPU                         0

#define configUSE_PREEMPTION                     1
#define configSUPPORT_STATIC_ALLOCATION          1
#define configSUPPORT_DYNAMIC_ALLOCATION         1
#define configUSE_IDLE_HOOK                      0
#define configUSE_TICK_HOOK                      0
#define configCPU_CLOCK_HZ                       ( SystemCoreClock )
#define configTICK_RATE_HZ                       ((TickType_t)1000)
#define configMAX_PRIORITIES                     ( 7 )
#define configMINIMAL_STACK_SIZE                 ((uint16_t)128)
//#define configTOTAL_HEAP_SIZE                    ((size_t)15360)
#define configTOTAL_HEAP_SIZE                    ((size_t)20480) //new size
#define configMAX_TASK_NAME_LEN                  ( 16 )
#define configUSE_16_BIT_TICKS                   0
#define configUSE_MUTEXES                        1
#define configQUEUE_REGISTRY_SIZE                8
#define configUSE_PORT_OPTIMISED_TASK_SELECTION  1
/* USER CODE BEGIN MESSAGE_BUFFER_LENGTH_TYPE */
/* Defaults to size_t for backward compatibility, but can be changed
   if lengths will always be less than the number of bytes in a size_t. */
#define configMESSAGE_BUFFER_LENGTH_TYPE         size_t
/* USER CODE END MESSAGE_BUFFER_LENGTH_TYPE */

/* Co-routine definitions. */
#define configUSE_CO_ROUTINES                    0
#define configMAX_CO_ROUTINE_PRIORITIES          ( 2 )

/* Set the following definitions to 1 to include the API function, or zero
to exclude the API function. */
#define INCLUDE_vTaskPrioritySet             1
#define INCLUDE_uxTaskPriorityGet            1
#define INCLUDE_vTaskDelete                  1
#define INCLUDE_vTaskCleanUpResources        0
#define INCLUDE_vTaskSuspend                 1
#define INCLUDE_vTaskDelayUntil              0
#define INCLUDE_vTaskDelay                   1
#define INCLUDE_xTaskGetSchedulerState       1
#define INCLUDE_xQueueGetMutexHolder         1
#define INCLUDE_eTaskGetState                1

/* Cortex-M specific definitions. */
#ifdef __NVIC_PRIO_BITS
 /* __BVIC_PRIO_BITS will be specified when CMSIS is being used. */
 #define configPRIO_BITS         __NVIC_PRIO_BITS
#else
 #define configPRIO_BITS         4
#endif

/* The lowest interrupt priority that can be used in a call to a "set priority"
function. */
#define configLIBRARY_LOWEST_INTERRUPT_PRIORITY   15

/* The highest interrupt priority that can be used by any interrupt service
routine that makes calls to interrupt safe FreeRTOS API functions.  DO NOT CALL
INTERRUPT SAFE FREERTOS API FUNCTIONS FROM ANY INTERRUPT THAT HAS A HIGHER
PRIORITY THAN THIS! (higher priorities are lower numeric values. */
#define configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY 5

/* Interrupt priorities used by the kernel port layer itself.  These are generic
to all Cortex-M ports, and do not rely on any particular library functions. */
#define configKERNEL_INTERRUPT_PRIORITY 		( configLIBRARY_LOWEST_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )
/* !!!! configMAX_SYSCALL_INTERRUPT_PRIORITY must not be set to zero !!!!
See http://www.FreeRTOS.org/RTOS-Cortex-M3-M4.html. */
#define configMAX_SYSCALL_INTERRUPT_PRIORITY 	( configLIBRARY_MAX_SYSCALL_INTERRUPT_PRIORITY << (8 - configPRIO_BITS) )

/* Normal assert() semantics without relying on the provision of an assert.h
header file. */
/* USER CODE BEGIN 1 */
#define configASSERT( x ) if ((x) == 0) {taskDISABLE_INTERRUPTS(); for( ;; );}
/* USER CODE END 1 */

/* Definitions that map the FreeRTOS port interrupt handlers to their CMSIS
standard names. */
#define vPortSVCHandler    SVC_Handler
#define xPortPendSVHandler PendSV_Handler

/* IMPORTANT: This define is commented when used with STM32Cube firmware, when the timebase source is SysTick,
              to prevent overwriting SysTick_Handler defined within STM32Cube HAL */

/* #define xPortSysTickHandler SysTick_Handler */

/* USER CODE BEGIN Defines */
/* Section where parameter definitions can be added (for instance, to override default ones in FreeRTOS.h) */
/* USER CODE END Defines */

#endif /* FREERTOS_CONFIG_H */




well, it wold SIGNIFICANTLY help if you disclosed right away WHAT asserts are being raised.

:roll_eyes:

//queqe.c
/* Cannot block if the scheduler is suspended. */
	#if ( ( INCLUDE_xTaskGetSchedulerState == 1 ) || ( configUSE_TIMERS == 1 ) )
	{
		configASSERT( !( ( xTaskGetSchedulerState() == taskSCHEDULER_SUSPENDED ) && ( xTicksToWait != 0 ) ) ); //<----
	}
	#endif

So that assert is trying to block on something before the scheduler has started, which isn’t allowed. Follow the stack trace to see what you are doing prescheduler that either needs to be changed.