From 30d65dbfe3add7f010a075991dc0bfeaebb7d9e1 Mon Sep 17 00:00:00 2001 From: Alain Knaff Date: Sun, 4 Jan 2009 22:46:17 +0100 Subject: bzip2/lzma: config and initramfs support for bzip2/lzma decompression Impact: New code for initramfs decompression, new features This is the second part of the bzip2/lzma patch The bzip patch is based on an idea by Christian Ludwig, includes support for compressing the kernel with bzip2 or lzma rather than gzip. Both compressors give smaller sizes than gzip. Lzma's decompresses faster than bzip2. It also supports ramdisks and initramfs' compressed using these two compressors. The functionality has been successfully used for a couple of years by the udpcast project This version applies to "tip" kernel 2.6.28 This part contains: - support for new compressions (bzip2 and lzma) in initramfs and old-style ramdisk - config dialog for kernel compression (but new kernel compressions not yet supported) Signed-off-by: Alain Knaff Signed-off-by: H. Peter Anvin --- init/Kconfig | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) (limited to 'init/Kconfig') diff --git a/init/Kconfig b/init/Kconfig index f6281711166d..df84625b1373 100644 --- 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) . (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 -- cgit v1.2.3 From 2e9f3bddcbc711bb14d86c6f068a779bf3710247 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Sun, 4 Jan 2009 15:41:25 -0800 Subject: bzip2/lzma: make config machinery an arch configurable Impact: Bug fix (we should not show this menu on irrelevant architectures) Make the config machinery to drive the gzip/bzip2/lzma selection dependent on the architecture advertising HAVE_KERNEL_* so that we don't display this for architectures where it doesn't matter. Signed-off-by: H. Peter Anvin --- init/Kconfig | 52 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 31 insertions(+), 21 deletions(-) (limited to 'init/Kconfig') diff --git a/init/Kconfig b/init/Kconfig index df84625b1373..f9633c03cb12 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -101,10 +101,20 @@ config LOCALVERSION_AUTO which is done within the script "scripts/setlocalversion".) +config HAVE_KERNEL_GZIP + bool + +config HAVE_KERNEL_BZIP2 + bool + +config HAVE_KERNEL_LZMA + bool + choice - prompt "Kernel compression mode" - default KERNEL_GZIP - help + prompt "Kernel compression mode" + default KERNEL_GZIP + depends on HAVE_KERNEL_GZIP || HAVE_KERNEL_BZIP2 || HAVE_KERNEL_LZMA + help The linux kernel is a kind of self-extracting executable. Several compression algorithms are available, which differ in efficiency, compression and decompression speed. @@ -123,34 +133,34 @@ choice 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. + bool "Gzip" + depends on HAVE_KERNEL_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" + depends on HAVE_KERNEL_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. + Decompression speed is slowest among the three. The kernel + 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 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. + bool "LZMA" + depends on HAVE_KERNEL_LZMA + help + The most recent compression algorithm. + Its ratio is best, decompression speed is between the other + two. Compression is slowest. The kernel size is about 33% + smaller with LZMA in comparison to gzip. endchoice - config SWAP bool "Support for paging of anonymous memory (swap)" depends on MMU && BLOCK -- cgit v1.2.3