新手linux 下mysql内存占用过高

系统是centos，内存只有512M，刚安装好一直不能启动服务，后来修改为 innodb_buffer_pool_size = 10M，便可以启动成功了，但是还是会占400M多，这样我连启动其他软件的内存都没有了，而且机器会比较慢，下面是我my.cnf的配置：

mysql版本是MySQL-server-5.6.16-1.rhel5.x86_64.rpm

# For advice on how to change settings please see
# http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html

[mysqld]
#Remove leading # and set to the amount of RAM for the most important data
# cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%.
innodb_buffer_pool_size = 10M

# Remove leading # to turn on a very important data integrity option: logging
# changes to the binary log between backups.
# log_bin

# These are commonly set, remove the # and set as required.
# basedir = .....
# datadir = .....
# port = .....
# server_id = .....
# socket = .....

# Remove leading # to set options mainly useful for reporting servers.
# The server defaults are faster for transactions and fast SELECTs.
# Adjust sizes as needed, experiment to find the optimal value.
join_buffer_size =256k
key_buffer_size = 24M
sort_buffer_size = 512k
read_rnd_buffer_size = 2M

thread_cache_size = 10
query_cache_size = 1M
query_cache_limit = 2M
query_cache_min_res_unit = 4K
sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES

小弟初接触linux，求大神指点，怎么配置能降低内存？ 感激不尽~