Booting a kernel inside a large file, out of memory?

[Sebert, Holger.ext]

Hi!

When booting a bzImage which is contained in a bigger file, does Grub
load the whole file into memory or does it only load the bzImage from
the file containing it?

Here is some background:

I have a file, say "myimage", which contains both a kernel (bzImage)
and a root filesystem (squashfs). The kernel is configured in a way to
automatically boot into that filesystem.

I am booting the kernel inside "myimage" successfully using the
following command:

    linux ($root)/myimage
    boot

The root filesystem being contained in "myimage" is currently not huge,
so it should fit into memory, but I am worried that this might change
in the future and I can get an out-of-memory-condition. Therefore my
question at the beginning of this mail.

Thanks!

Best,
Holger