How to resolve "Error log file size is increasing in mysql 5.5" issue w/o restarting mysql
Put the following parameters in your my.cnf and then restart the service:-

skip-name-resolve
log-warnings=1


The above activity will solve your  issue.

Try to check this link also:-

https://serverfault.com/questions/341290/mysql-warning-ip-address-could-not-be-resolved