composer Cannot allocate memory in phar:///usr/local/bin/composer/vendor/symfony/console/Application.php on line 952 code example

Example: mmap() failed: [12] Cannot allocate memory composer

/bin/dd if=/dev/zero of=/var/swap.1 bs=1M count=1024
/sbin/mkswap /var/swap.1
/sbin/swapon /var/swap.1