Comment 10 for bug 1878541

The minimum reproducer i have is this:

1) Fetch UC20 image from http://cdimage.ubuntu.com/ubuntu-core/20/edge/pending/
2) boot to grub cmdline prompt
2) execute

loopback loop (hd0,gpt3)/pc-kernel_502.snap

(or use tabcompletion for the right kernel snap)

Equivalent command on UC18 image (with bionic's grub) result in no additional memory used, with the same kernel snap.

On UC20 image, executing that command uses up 400MB of RAM which does not appear to be reclaimed.

It appears to be irrelevant as to what underlying fs type is (UC18 had kernel snap on ext4, UC20 has it on ESP/fat).