Commit 3e4e0f0a authored by Paul Bolle's avatar Paul Bolle Committed by Linus Torvalds

initramfs: remove "compression mode" choice

Commit 9ba4bcb6 ("initramfs: read CONFIG_RD_ variables for initramfs
compression") removed the users of the various INITRAMFS_COMPRESSION_*
Kconfig symbols.  So since v3.13 the entire "Built-in initramfs
compression mode" choice is a set of knobs connected to nothing.  The
entire choice can safely be removed.
Signed-off-by: 's avatarPaul Bolle <>
Cc: P J P <>
Signed-off-by: 's avatarAndrew Morton <>
Signed-off-by: 's avatarLinus Torvalds <>
parent 04541a2f
......@@ -98,80 +98,3 @@ config RD_LZ4
Support loading of a LZ4 encoded initial ramdisk or cpio buffer
If unsure, say N.
prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
This option decides by which algorithm the builtin initramfs
will be compressed. Several compression algorithms are
available, which differ in efficiency, compression and
decompression speed. Compression speed is only relevant
when building a kernel. Decompression speed is relevant at
each boot.
If you have any problems with bzip2 or LZMA compressed
initramfs, mail me (Alain Knaff) <>.
High compression options are mostly useful for users who are
low on RAM, since it reduces the memory consumption during
If in doubt, select 'gzip'
bool "None"
Do not compress the built-in initramfs at all. This may
sound wasteful in space, but, you should be aware that the
built-in initramfs will be compressed at a later stage
anyways along with the rest of the kernel, on those
architectures that support this.
However, not compressing the initramfs may lead to slightly
higher memory consumption during a short time at boot, while
both the cpio image and the unpacked filesystem image will
be present in memory simultaneously
bool "Gzip"
depends on RD_GZIP
The old and tried gzip compression. It provides a good balance
between compression ratio and decompression speed.
bool "Bzip2"
depends on RD_BZIP2
Its compression ratio and speed is intermediate.
Decompression speed is slowest among the choices. The initramfs
size is about 10% smaller with bzip2, in comparison to gzip.
Bzip2 uses a large amount of memory. For modern kernels you
will need at least 8MB RAM or more for booting.
bool "LZMA"
depends on RD_LZMA
This algorithm's compression ratio is best.
Decompression speed is between the other choices.
Compression is slowest. The initramfs size is about 33%
smaller with LZMA in comparison to gzip.
bool "XZ"
depends on RD_XZ
XZ uses the LZMA2 algorithm. The initramfs size is about 30%
smaller with XZ in comparison to gzip. Decompression speed
is better than that of bzip2 but worse than gzip and LZO.
Compression is slow.
bool "LZO"
depends on RD_LZO
Its compression ratio is the poorest among the choices. The kernel
size is about 10% bigger than gzip; however its speed
(both compression and decompression) is the fastest.
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