[linux-lvm] Error creating snapshot, "Cannot allocate memory"

[jheiss-linuxlvm at ofb.net]

I have a volume group that is 1.4 TB, with a volume that is 400 GB.
I currently have three 50 GB snapshots of that volume.  When I try
to create a fourth, I get the following error:

bash-2.05a# lvcreate -L 50G -s -n snap_home1_20021202 /dev/home/home1
lvcreate -- WARNING: the snapshot will be automatically disabled once it
gets full
lvcreate -- INFO: using default snapshot chunk size of 64 KB for
"/dev/home/snap_home1_20021202"
lvcreate -- ERROR "Cannot allocate memory" creating VGDA for
"/dev/home/snap_home1_20021202" in kernel

After some experimenting, I found that I could create a snapshot that
is 36 GB or smaller, but anything larger than 36 GB fails with the above
error.  The volume group has 386 GB free.

Any thoughts?  I looked through the changelog and mailing list archives
and couldn't find anything similar.

Other possibly useful bits of info:

OS:  Red Hat 7.3
kernel:  2.4.18-18.7.xsmp
LVM:  1.0.3-4  (Red Hat RPM)

Jason