title: Can i give mapped memory to malloc?
body: <p>Say I have a big block of mapped memory I finished using. It came from <code>mmap</code>ing anonymous memory or using <code>MAP_PRIVATE</code>. I could <code>munmap</code> it, then have <code>malloc</code> <code>mmap</code> again the next time I make a big enough allocation.</p>
  
  <p>Could I instead give the memory to <code>malloc</code> directly? Could I say "Hey <code>malloc</code>, here's an address range I mapped. Go use it for heap space. Feel free to <code>mprotect</code>, <code>mremap</code>, or even <code>munmap</code> it as you wish."?</p>
  
  <p>I'm using glibc on linux.</p>