title: Alignment of pointers for lock-free algorithms
body: <p>When calloc is being used pointers to newly allocated memory are aligned to at least certian number of the least significant bits, meaning that least significent bits(as tagged pointeres) can be used for lock-free algorithms, and in fact is commonly used in case of those algorithms. I was testing memory menagment feature on linux ubuntu server( x86_64 GNU/Linux, 3.10.23-xxxx-std-ipv6-64-vps) and it seems, from my experiments, that the  4  least significant bits are set to 0. From what i have read it states that pointer alignment is formed in such a way for pointer expressed as uintptr to be divided by 4(alignment to 2 least significant bits)</p>
  
  <p>What is the minimum number of the least significant bits in newly allocated memory pointers, obtained from memory menagment system in POSIX (linux), that are always set to 0 during initial memory allocation process?</p>
  
  <p>What is the maximum number of the least significant bits that can be used as tagged pointers on linux systems (eg. lock-free algorithms)?</p>
  
  <p>How to force compiler to align newly allocated pointers to exect number of the least significant bits ?</p>
  
  <p>Does the alignment of pointers affect system overall performance, and how ?</p>