How to use SystemView Heap Monitoring - Custom Heap

This article assumes a working SystemView setup. To gain some more info on this subject, please consult either the main article (How to use SystemView Heap_Monitoring) or the SystemView documentation.

Note that the size reported to SystemView should be the internally allocated size minus the meta data, not the size requested buy a user. The __heap_start__ is a symbol that is defined if the heap region is allocated in the linker script.

Allocating the memory should be accompanied by a call to SEGGER_SYSVIEW_HeapAlloc:

static void* _MyMalloc(size_t size) {
  void* p = ... // a call to a custom alloc routine
  // SystemView needs the real internal heap block size, not the amount requested by the user
  SEGGER_SYSVIEW_HeapAlloc(__heap_start__, p, _GetAllocBlockSize(size));
  return p;
}

Freeing the memory should be accompanied by a call to SEGGER_SYSVIEW_HeapFree:

static void _MyFree(void* p) {
  ... // a call to a custom freeing routine
  SEGGER_SYSVIEW_HeapFree(__heap_start__, p);
}

Since there is no dedicated realloc SystemView API function, a combination of SEGGER_SYSVIEW_HeapFree and SEGGER_SYSVIEW_HeapAlloc is needed:

static void* _MyRealloc(void* p, size_t size) {
  void* rp = ... // a call to a custom realloc routine
  SEGGER_SYSVIEW_HeapFree(__heap_start__, p);
  // SystemView needs the real internal heap block size, not the amount requested by the user
  SEGGER_SYSVIEW_HeapAlloc(__heap_start__, rp, _GetAllocBlockSize(size));
  return rp;
}