How to reduce memory usage in linux

[zhiyang hu]

when I open a new page. the linux devtool show usaged memory is only 

but when I cat process linux memory. it's show much higher.

why and how can I slow down memory usage in linux

huzhiyang@ubuntu:/proc/33305$ cat /proc/32854/status

Name:    chrome
Umask:    0002
State:    S (sleeping)
Tgid:    32854
Ngid:    0
Pid:    32854
PPid:    32760
TracerPid:    0
Uid:    1000    1000    1000    1000
Gid:    1000    1000    1000    1000
FDSize:    256
Groups:    4 24 27 30 46 120 132 133 134 1000
NStgid:    32854    34    1
NSpid:    32854    34    1
NSpgid:    32747    0    0
NSsid:    32712    0    0
VmPeak:    1187331672 kB
VmSize:    1184843272 kB
VmLck:           0 kB
VmPin:           0 kB
VmHWM:      160008 kB
VmRSS:      160008 kB