title: Is SCHED_FIFO thread rescheduled to the end of a list after sleeping
body: <p>As the <a href="https://man7.org/linux/man-pages/man7/sched.7.html" rel="nofollow noreferrer">sched(7)</a> man page says:</p>
  <blockquote>
  <ol start="2">
  <li>When a blocked SCHED_FIFO thread becomes runnable, it will be inserted at the end of the list for its priority.</li>
  </ol>
  </blockquote>
  <p>But officially there is no <em>blocked</em> state of a thread - there are only <em>Interruptible Sleep (S)</em> and <em>Uninterruptible Sleep (D)</em>.</p>
  <p>Questions:</p>
  <ol>
  <li>If a thread is sleeping on <a href="https://man7.org/linux/man-pages/man2/select.2.html" rel="nofollow noreferrer">select(2)</a> or <a href="https://man7.org/linux/man-pages/man2/clock_nanosleep.2.html" rel="nofollow noreferrer">clock_nanosleep(2)</a>, is that the <em>Interruptible Sleep</em> (both can be woken up on a signal)? I assume probably yes for both.</li>
  <li>After <em>Interruptible Sleep</em>, is the thread placed at the end of the scheduling list?</li>
  <li>The same as 2. but for <em>Uninterruptible Sleep</em>?</li>
  </ol>
  <p>I think that answer to all of the questions is &quot;Yes&quot; but I have to be sure.</p>