Size requested from sbrk is not the actual size needed.

[patacongo]

Originally, there was logic like the following for KERNEL mode in mm/mm_heap/:

  brkaddr = sbrk(size);

When we modified this to handle the case of size == 0, this became:

  brkaddr = sbrk(size < 1 ? 1 : size);

But there still could be an issue here. Not just for size < 1 for for all sizes. The sizes don't include quantization overhead, or the overhead from the memory header. So the amount of memory requested is smaller than that which is actually needed. If nothing else, that does leave me a little uneasy.

I am thinking it should be like:

  chunksize = size < MM_MIN_CHUNK ? (size + (MM_MIN_CHUNK - 1)) % MM_MIN_CHUNK
  brkaddr = sbrk(chunksize);

But I have not looked at the detailed logic in sbrk to see how it handles the size. Perhaps there is no problem. This issue is simply to verify that that is the case.

As has been pointed out MM_MIN_CHUNK is not valid for tlsf_realloc(). But even if tlsf_realloc() and mm_realloc() are different in this way, that would not change the issue, that would just make any solution that might be needed more difficult (and I'm not even certain that any solution is needed).