Question

I have a code that has a large number of mallocs and device-specific API mallocs (I’m programming on a GPU, so cudaMalloc).

Basically my end of my beginning of my code is a big smorgasbord of allocation calls, while my closing section is deallocation calls.

As I’ve encapsulated my global data in structures, the deallocations are quite long, but at least I can break them into a separate function. On the other hand, I would like a shorter solution. Additionally an automatic deallocator would reduce the risk of memory leaks created if I forget to explicitly write the deallocation in the global allocator function.

I was wondering whether it’d be possible to write some sort of templated class wrapper that can allow me to “register” variables during the malloc/cudaMalloc process, and then at the end of simulation do a mass loop-based deallocation (deregistration). To be clear I don’t want to type out individual deallocations (free/cudaFrees), because again this is long and undesirable, and the assumption would be that anything I register won’t be deallocated until the device simulation is complete and main is terminating.

A benefit here is that if I register a new simulation duration variable, it will automatically deallocate, so there’s no danger of me forgetting do deallocate it and creating a memory leak.

Is such a wrapper possible?

Would you suggest doing it?

If so, how?

Thanks in advance!

Answer 1

An idea:

Create both functions, one that allocates memory and provides valid pointers after register them in a “list” of allocated pointers. In the second method, loop this list and deallocate all pointers:

// ask for new allocated pointer that will be registered automatically in list of pointers.
pointer1 = allocatePointer(size, listOfPointers);
pointer2 = allocatePointer(size, listOfPointers);

...
// deallocate all pointers
deallocatePointers(listOfPointers);

Even, you may use different listOfPointers depending of your simulation scope:

listOfPointer1 = getNewListOfPointers();
listOfPointer2 = getNewListOfPointers();
....
p1 = allocatePointer(size, listOfPointer1);
p2 = allocatePointer(size, listOfPointer2);
...
deallocatePointers(listOfPointers1);
...
deallocatePointers(listOfPointers2);