title: What's the unit of `ru_maxrss` on Linux?
body: <p>This is from <code>man getrusage</code></p>
  
  <pre><code>struct rusage {
      struct timeval ru_utime; /* user time used */
      struct timeval ru_stime; /* system time used */
      long   ru_maxrss;        /* maximum resident set size */
      long   ru_ixrss;         /* integral shared memory size */
      long   ru_idrss;         /* integral unshared data size */
      long   ru_isrss;         /* integral unshared stack size */
      long   ru_minflt;        /* page reclaims */
      long   ru_majflt;        /* page faults */
      long   ru_nswap;         /* swaps */
      long   ru_inblock;       /* block input operations */
      long   ru_oublock;       /* block output operations */
      long   ru_msgsnd;        /* messages sent */
      long   ru_msgrcv;        /* messages received */
      long   ru_nsignals;      /* signals received */
      long   ru_nvcsw;         /* voluntary context switches */
      long   ru_nivcsw;        /* involuntary context switches */
  };
  </code></pre>
  
  <p>However it's not specified what's the unit.</p>
  
  <p>I saw FreeBSD's documentation which says it's in kilobytes, but I'm not sure about what unit it is on Linux.</p>