How To Resize /dev/shm Filesystem In Linux?

1) Open /etc/fstab with vi or any text editor of your choice
2) Locate the line of /dev/shm and use the tmpfs size option to specify your expected size

e.g.
tmpfs /dev/shm tmpfs defaults,size=1500m 0 0

or

e.g

tmpfs /dev/shm tmpfs defaults,size=2g 0 0

3) To make change effective immediately, run this mount command to remount the /dev/shm filesystem:

mount -o remount /dev/shm

that's all.
thank.