use a tmpfs for chroot-livecd if the machine has > 1GB of RAM, Release 1.115

debian/changelog

@@ -1,3 +1,10 @@
+livecd-rootfs (1.115) maverick; urgency=low
+
+  * use a tmpfs for the livefs root directory, to get some speed
+    on the build machines. (ubuntu-dvd requires > 5GB, so use 8GB)
+
+ -- LaMont Jones <lamont@ubuntu.com>  Wed, 05 May 2010 10:42:00 -0600
+
 livecd-rootfs (1.114) lucid; urgency=low
 
   * make sure STRIP_VMLINUZ=no is set for omap, also change the code to only

livecd.sh

@@ -167,7 +167,13 @@ for FS in "$@"; do
     # Just in case there's some leftover junk here:
     cleanup 2>/dev/null || true
 
+    umount ${ROOT} || true
     rm -rf ${ROOT}
+    mkdir ${ROOT}
+    # if we have > 1GB of RAM, use a tmpfs
+    if  awk '/^MemTotal:/ { exit !(int($2/1024) > 1024)}' /proc/meminfo; then
+        mount -t tmpfs -o size=8192M tmpfs ${ROOT} && echo using tmpfs
+    fi
 
     mkdir -p ${ROOT}var/cache/debconf
     cat << @@EOF > ${ROOT}var/cache/debconf/config.dat