diff options
| -rw-r--r-- | usr/Kconfig | 62 | ||||
| -rw-r--r-- | usr/Makefile | 18 |
2 files changed, 68 insertions, 12 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 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 diff --git a/usr/Makefile b/usr/Makefile index 451cdff7dff..b84894b3929 100644 --- a/usr/Makefile +++ b/usr/Makefile @@ -5,24 +5,18 @@ klibcdirs:; PHONY += klibcdirs -# Find out "preferred" ramdisk compressor. Order of preference is -# 1. bzip2 efficient, and likely to be present -# 2. gzip former default -# 3. lzma -# 4. none -# None of the above -suffix_y = - -# Lzma, but no gzip nor bzip2 -suffix_$(CONFIG_RD_LZMA) = .lzma +# No compression +suffix_$(CONFIG_INITRAMFS_COMPRESSION_NONE) = # Gzip, but no bzip2 -suffix_$(CONFIG_RD_GZIP) = .gz +suffix_$(CONFIG_INITRAMFS_COMPRESSION_GZIP) = .gz # Bzip2 -suffix_$(CONFIG_RD_BZIP2) = .bz2 +suffix_$(CONFIG_INITRAMFS_COMPRESSION_BZIP2) = .bz2 +# Lzma +suffix_$(CONFIG_INITRAMFS_COMPRESSION_LZMA) = .lzma # Generate builtin.o based on initramfs_data.o obj-$(CONFIG_BLK_DEV_INITRD) := initramfs_data$(suffix_y).o |