public function memoryUsage()
    {
        $total = 0;
        $free = 0;
        $memInfo = '/proc/meminfo';
        $totalIsFound = false;
        $freeIsFound = false;

        if (file_exists($memInfo)) {
            $handle = @fopen($memInfo, 'r');

            if ($handle) {
                while (!feof($handle)) {
                    $buffer = fgets($handle, 4096);

                    if (!$totalIsFound && strpos($buffer, 'MemTotal:') !== false) {
                        sscanf($buffer, 'MemTotal: %d', $total);
                        $totalIsFound = true;
                        continue;
                    }

                    if (!$freeIsFound && strpos($buffer, 'MemFree:') !== false) {
                        sscanf($buffer, 'MemFree: %d', $free);
                        $freeIsFound = true;
                    }

                    if ($totalIsFound && $freeIsFound) {
                        break;
                    }
                }
            }

            @fclose($handle);
        }

        $percent = 100;

        if ($total > 0 && $free > 0) {
            $percent = 100 - ((int)$free / ((int)$total / 100));
        }

        return [
            'total' => (int)$total * 1024,
            'free' => (int)$free * 1024,
            'usage' => (string)number_format($percent, 2)
        ];
    }