Even better, you can just put the whole root fs into the initramfs image, and never pivot to another root filesystem during boot. This also allows you to netboot a whole OS.
Or if you set rootfstype=ramfs, then you can take up to all of physical RAM, but ramfs isn't swappable.
Initramfs (and tmpfs) are swappable right? As you say, ramfs is the one that isn't swappable. So if your initramfs is "to big" can't it just be swapped out?
It makes sense if you replace "initramfs" with "initrd":
> One pitfall of this is that the decompressed contents of your ~initramfs~ _initrd_ must fit within half of your physical RAM since Linux decompresses it into a tmpfs. > Or if you set rootfstype=ramfs, then you can take up to all of physical RAM