title: Reasonable valid start address for mmap address hint so as to be gauranteed that things work
body: <p>In one of our assignments we are required to build a distributed shared memory between 2 machines, I was using a paging based technique such that the base addresses are different on both the machines. But there is this linked list test case which almost mandates that both address ranges are same. mmap's fixed address using MAP_FIXED causes the slave machine to crash( because the stack of the reply server thread was getting overwritten ), i figured that creating an address that is gauranteed to be free at the very start during initialization on both processes would be reasonable. However, after hours of scouring the net i am still unlucky in finding that default address. Our requirement is 10000 pages. If someone could point the base of heap address beyond which sbrk is gauranteed not to grow i could use that. </p>
  
  <p>Best,
  Subramanian</p>