1. Simple way to do it is to run following command:
top -o %MEM
2. Output below
[root@ip-x-x-x-x xinetd.d]# top -o %MEM
top - 15:24:13 up 8:02, 1 user, load average: 0.01, 0.31, 0.25
Tasks: 107 total, 1 running, 66 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.0 us, 0.2 sy, 0.0 ni, 99.3 id, 0.3 wa, 0.0 hi, 0.0 si, 0.2 st
KiB Mem : 472500 total, 227492 free, 185308 used, 59700 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 274136 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
2275 mysql 20 0 1771192 65264 0 S 0.0 13.8 0:09.53 mysqld
1384 root 20 0 65632 12376 12000 S 0.0 2.6 0:00.66 systemd-journal
2833 apache 20 0 1923848 10644 152 S 0.0 2.3 0:05.61 httpd
2572 apache 20 0 2050504 9232 108 S 0.0 2.0 0:05.78 httpd
2571 apache 20 0 1921608 9196 72 S 0.3 1.9 0:05.60 httpd
2573 apache 20 0 1917128 8064 88 S 0.0 1.7 0:05.63 httpd
2258 root 20 0 398704 7360 896 S 0.0 1.6 0:01.19 httpd
3. As per above, we can see that mysql process is the top memory eater.