path: root/usr/Kconfig
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Diffstat (limited to 'usr/Kconfig')
1 files changed, 62 insertions, 0 deletions
diff --git a/usr/Kconfig b/usr/Kconfig
index a691a8f5898..43a3a0fe8f2 100644
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -71,3 +71,65 @@ config RD_LZMA
Support loading of a lzma encoded initial ramdisk or cpio buffer
If unsure, say N.
+ prompt "Built-in initramfs compression mode"
+ help
+ This setting is only meaningful if the INITRAMFS_SOURCE is
+ set. It decides by which algorithm the INITRAMFS_SOURCE 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 disk space (embedded systems), but for whom ram
+ size matters less.
+ If in doubt, select 'gzip'
+ bool "None"
+ help
+ 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
+ help
+ The old and tried gzip compression. Its compression ratio is
+ the poorest among the 3 choices; however its speed (both
+ compression and decompression) is the fastest.
+ bool "Bzip2"
+ depends on RD_BZIP2
+ help
+ Its compression ratio and speed is intermediate.
+ Decompression speed is slowest among the three. 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
+ help
+ The most recent compression algorithm.
+ Its ratio is best, decompression speed is between the other
+ two. Compression is slowest. The initramfs size is about 33%
+ smaller with LZMA in comparison to gzip.