PHP memory usage as reported by the kernel

kernel-memory-usage.php

<?php

function memory_get_process_usage()
{
  $status = file_get_contents('/proc/' . getmypid() . '/status');

  $matchArr = [];
  preg_match_all('~^(VmRSS|VmSwap):\s*([0-9]+).*$~im', $status, $matchArr);

  if (!isset($matchArr[2][0], $matchArr[2][1])) {
    return false;
  }

  return ((int)$matchArr[2][0] + (int)$matchArr[2][1]) / 1024;
}