- Add support for a zstd compressed initramfs.
- Add compression for compressing built-in initramfs with zstd.
I have tested this patch by boot testing with buildroot and QEMU.
Specifically, I booted the kernel with both a zstd and gzip compressed
initramfs, both built into the kernel and separate. I ensured that the
correct compression algorithm was used. I tested on arm, aarch64, i386,
This patch has been tested in production on aarch64 and x86_64 devices.
Additionally, I have performance measurements from internal use in
production. On an aarch64 device we saw 19 second boot time improvement
from switching from lzma to zstd (27 seconds to 8 seconds). On an x86_64
device we saw a 9 second boot time reduction from switching from xz to
Signed-off-by: Nick Terrell <email@example.com>
Signed-off-by: Ingo Molnar <firstname.lastname@example.org>
Tested-by: Sedat Dilek <email@example.com>
Reviewed-by: Kees Cook <firstname.lastname@example.org>