getting memory allocation error in codeigniter HMVC - php

Question

Description: I created simple login page with session and mysql database using PHP,MySQL Database,CodeIgniter(HMVC) and XAMPP Server in local system.
Problem: I am getting following error:
Fatal error: Allowed memory size of 134217728 bytes exhausted (tried to allocate 65488 bytes) in C:\xampp\htdocs\ci\application\third_party\MX\Modules.php on line 114.
Question: Please tell me the solution how to resolve this above error.
View:
*login2.php*
<?php echo form_open(/* base_url(). */'user/user/login'); ?>
<?php
if ($this->session->flashdata('login_error')) {
echo 'you have entered an incorrect username or password';
}
echo validation_errors();
?>
<label>UserName</label>
<div>
<?php echo form_input(array('id' => 'username', 'name' => 'username', 'placeholder' => 'Enter ur name')); ?>
</div>
<label>Password</label>
<div>
<?php echo form_password(array('id' => 'password', 'name' => 'password', 'placeholder' => 'Enter ur password')); ?>
</div>
<div>
<?php echo form_submit(array('name' => 'submit'), 'Login'); ?>
</div>
<?php echo form_close(); ?>
Controller:
*user.php*
<?php
class User extends CI_Controller {
function __construct() {
parent::__construct();
}
function index() {
$this->login();
}
function main_page() {
echo 'You are logged in';
}
function login() {
$this->form_validation->set_rules('username', 'Username', 'required|trim|max_length[50]|xss_clean');
$this->form_validation->set_rules('password', 'Password', 'required|trim|max_length[200]|xss_clean');
if ($this->form_validation->run() == FALSE) {
$this->load->view('login2');
} else { // process their input and login the user
extract($_POST);
$user_id = $this->user->login($username, $password);
if ($user_id) {
//login failed error...
$this->session->set_flashdata('login_error', TRUE);
redirect('user/login');
} else {
//logem in
$this->session->set_userdata(array(
'logged_in' => TRUE,
'user_id' => $user_id
));
redirect('user/main_page');
}
}
}
}
?>
Model:
*user.php*
<?php
Class User extends CI_Model {
function login($username, $password) {
$this->db->select('id, username, password');
$this->db->from('users');
$this->db->where('username', $username);
$this->db->where('password', MD5($password));
$this->db->limit(1);
$query = $this->db->get();
if ($query->num_rows() == 1) {
return $query->result();
} else {
return false;
}
}
}
?>