root@snic10e:/tmp# while true; do
>     echo "dnsmasq restart"
>     service dnsmasq restart
>     sleep 1
>     echo "before cache drop:"
>     free
>     sleep 1
>     echo 3 > /proc/sys/vm/drop_caches
>     sleep 1
>     echo "after cache drop:"
>     free
>     sleep 1
> done
dnsmasq restart
before cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       87948     1883424       17488       20136     1860172
Swap:             0           0           0
[ 4129.167679] ash (634): drop_caches: 3
after cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       88004     1883368       17488       20136     1860116
Swap:             0           0           0
dnsmasq restart
before cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       88344     1882980       17488       20184     1859752
Swap:             0           0           0
[ 4133.589184] ash (634): drop_caches: 3
after cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       88360     1882964       17488       20184     1859736
Swap:             0           0           0
dnsmasq restart
before cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       89720     1881604       17488       20184     1858376
Swap:             0           0           0
[ 4138.010682] ash (634): drop_caches: 3
after cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       89576     1881748       17488       20184     1858520
Swap:             0           0           0
dnsmasq restart
before cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       89868     1881468       17480       20172     1858240
Swap:             0           0           0
[ 4142.434119] ash (634): drop_caches: 3
after cache drop:
              total        used        free      shared  buff/cache   available
Mem:        1991508       89840     1881488       17488       20180     1858260
Swap:             0           0           0
dnsmasq restart
^C
root@snic10e:/tmp#