root@*******-215:~# free -m
         total        used        free      shared  buff/cache   available
Mem:      9819        5528         362        3433        3928         597
Swap:     2047        1612         435

root@*******-215:~# echo 3 > /proc/sys/vm/drop_caches
root@*******-215:~# free -m
         total        used        free      shared  buff/cache   available
Mem:      9819        5697         268        3444        3853         436
Swap:     2047        1372         675