bzip2/lzma: make internal initramfs compression configurable

[net-next-2.6.git] / usr / Kconfig

diff --git a/usr/Kconfig b/usr/Kconfig
index a691a8f5898b5fa5f3b0eda9412ad3d8d3716fa4..43a3a0fe8f29b3637bcd49eb0d3824d5da67d2a6 100644 (file)
--- a/usr/Kconfig
+++ b/usr/Kconfig
@@ -71,3 +71,65 @@ config RD_LZMA
        help
          Support loading of a lzma encoded initial ramdisk or cpio buffer
          If unsure, say N.
+
+choice
+       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) <alain@knaff.lu>.
+
+         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'
+
+config INITRAMFS_COMPRESSION_NONE
+       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
+
+config INITRAMFS_COMPRESSION_GZIP
+       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.
+
+config INITRAMFS_COMPRESSION_BZIP2
+       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.
+
+config INITRAMFS_COMPRESSION_LZMA
+       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.
+
+endchoice