PHP Fatal error: Allowed memory size of 1610612736 bytes exhausted

Ejecutando

composer update

en una máquina virtual Linux (Laravel Homestead), obtengo este error:

PHP Fatal error:  Allowed memory size of 1610612736 bytes exhausted (tried to allocate 72 bytes) in phar:///usr/local/bin/composer/src/Composer/DependencyResolver/RuleSetGenerator.php on line 64

Fatal error: Allowed memory size of 1610612736 bytes exhausted (tried to allocate 72 bytes) in phar:///usr/local/bin/composer/src/Composer/DependencyResolver/RuleSetGenerator.php on line 64

Check https://getcomposer.org/doc/articles/troubleshooting.md#memory-limit-errors for more info on how to handle out of memory errors.