title: Is there a global "current" for each core if Linux is running on a multicore CPU?
body: <p>Some book says</p>
  
  <blockquote>
    <p>The <strong>current</strong> pointer refers to the user process currently executing.
    During the execution of a system call, such as <strong>open</strong> or <strong>read</strong>, the
    current process is the one that invoked the call.</p>
  </blockquote>
  
  <p>What if multiple processes are calling a system call (same or different system calls) at the same time on a multicore CPU, one on each core? Does the kernel need multiple "current" global variables for them?</p>