Enlarge /tmp and /dev/shm

Initial size of those tmpfs-mounted directories is calculated as 50% of
RAM at VM startup time. Which happen to be quite small number, like
150M. Having such small /tmp and/or /dev/shm apparently isn't enough for
some applications like Google chrome. So set the size statically at 1GB,
which would be the case for baremetal system with 2GB of RAM.

Fixes QubesOS/qubes-issues#1003

Makefile

@@ -54,6 +54,7 @@ DROPIN_DIR ?= "lib/systemd/system"
 # Fedora Dropins
 DROPINS := chronyd.service crond.service cups.service cups.path cups.socket ModemManager.service
 DROPINS += NetworkManager.service NetworkManager-wait-online.service ntpd.service getty@tty.service
+DROPINS += tmp.mount
 
 # Debian Dropins
 ifeq ($(shell lsb_release -is), Debian)

misc/fstab

@@ -5,7 +5,7 @@
 /dev/xvdb		/rw			auto	noauto,defaults,discard	1 2
 /rw/home        /home       none    noauto,bind,defaults 0 0
 /dev/xvdc1      swap                    swap    defaults        0 0
-tmpfs                   /dev/shm                tmpfs   defaults        0 0
+tmpfs                   /dev/shm                tmpfs   defaults,size=1G        0 0
 devpts                  /dev/pts                devpts  gid=5,mode=620  0 0
 sysfs                   /sys                    sysfs   defaults        0 0
 proc                    /proc                   proc    defaults        0 0

rpm_spec/core-vm.spec

@@ -555,6 +555,7 @@ The Qubes core startup configuration for SystemD init.
 /lib/systemd/system/NetworkManager.service.d/30_qubes.conf
 /lib/systemd/system/NetworkManager-wait-online.service.d/30_qubes.conf
 /lib/systemd/system/ntpd.service.d/30_qubes.conf
+/lib/systemd/system/tmp.mount.d/30_qubes.conf
 
 %post systemd
 

vm-systemd/tmp.mount.d/30_qubes.conf

@@ -0,0 +1,4 @@
+[Mount]
+# Default initial size is '50%' (of physical RAM at system startup)
+# Because of memory ballooning this happen to be very low number
+Options=mode=1777,strictatime,size=1G