bzip2/lzma: config and initramfs support for bzip2/lzma decompression

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

diff --git a/init/Kconfig b/init/Kconfig
index f6281711166d5dbeba4f55121547396d00b6ff2e..df84625b1373648f0224307f381c2ba24524e2e0 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -101,6 +101,56 @@ config LOCALVERSION_AUTO
 
          which is done within the script "scripts/setlocalversion".)
 
+choice
+        prompt "Kernel compression mode"
+        default KERNEL_GZIP
+        help
+         The linux kernel is a kind of self-extracting executable.
+         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
+         kernels, mail me (Alain Knaff) <alain@knaff.lu>. (An older
+         version of this functionality (bzip2 only), for 2.4, was
+         supplied by Christian Ludwig)
+
+         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 KERNEL_GZIP
+       bool "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 KERNEL_BZIP2
+       bool "Bzip2"
+       help
+         Its compression ratio and speed is intermediate.
+         Decompression speed is slowest among the 3.
+         The kernel size is about 10 per cent 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 KERNEL_LZMA
+       bool "LZMA"
+       help
+         The most recent compression algorithm.
+        Its ratio is best, decompression speed is between the other
+        2. Compression is slowest.
+        The kernel size is about 33 per cent smaller with lzma,
+        in comparison to gzip.
+
+endchoice
+
+
 config SWAP
        bool "Support for paging of anonymous memory (swap)"
        depends on MMU && BLOCK