linux mount points

[Scoofy12]

for the linux gurus... not sure if this is a dumb question or not... i know you can use partitions for your /usr or /home directories by just setting the mount point for /dev/hdXX as /usr but is there any way to let /usr and /home share a partition? so that there is a pool of space that can be filled by either, rather than arbitrarily restricting each to a certain percentage of my drive?


and, failing that, ill just move my /usr directory to the new partition. is there anything i need to do other than cp'ing all the stuff from /usr into the root of the new filesystem and changing /etc/fstab? can i complete it without rebooting (i think so, as mount is in /bin, so i can just rm -rf /usr/* and mount /usr )