I'm creating a list of elements inside a task in the following way:
l = (dllist*)pvPortMalloc(sizeof(dllist));
dllist is 32 byte big. My embedded system has 60kB SRAM so I expected my 200 element list can be handled easily by the system. I found out that after allocating space for 8 elements the system is crashing on the 9th malloc function call (256byte+).
If possible, where can I change the heap size inside freeRTOS? Can I somehow request the current status of heap size? I couldn't find this information in the documentation so I hope somebody can provide some insight in this matter. Thanks in advance!
(Yes - FreeRTOS pvPortMalloc() returns void*.)
If you have 60K of SRAM, and configTOTAL_HEAP_SIZE is large, then it is unlikely you are going to run out of heap after allocating 256 bytes unless you had hardly any heap remaining before hand. Many FreeRTOS demos will just keep creating objects until all the heap is used, so if your application is based on one of those, then you would be low on heap before your code executed. You may have also done something like use up loads of heap space by creating tasks with huge stacks.
heap_4 and heap_5 will combine adjacent blocks, which will minimise fragmentation as far as practical, but I don't think that will be your problem - especially as you don't mention freeing anything anywhere.
Unless you are using heap_3.c (which just makes the standard C library malloc and free thread safe) you can call xPortGetFreeHeapSize() to see how much free heap you have. You may also have xPortGetMinimumEverFreeHeapSize() available to query how close you have ever come to running out of heap. More information: http://www.freertos.org/a00111.html
You could also define a malloc() failed hook (http://www.freertos.org/a00016.html) to get instant notification of pvPortMalloc() returning NULL.