title: How is malloc() implemented internally?
body: <p>Can anyone explain how <code>malloc()</code> works internally?</p>
  
  <p>I have sometimes done <code>strace program</code> and I see a lot of <code>sbrk</code> system calls, doing <code>man sbrk</code> talks about it being used in <code>malloc()</code> but not much more.</p>