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![Randy Dunlap](/assets/img/avatar_default.png)
There have been new compression algorithms added without updating nearby relevant descriptive text that refers to (a) the number of compression algorithms and (b) the most recent one. Fix these inconsistencies. Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Reported-by: <qasdfgtyuiop@gmail.com> Cc: Lasse Collin <lasse.collin@tukaani.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Markus Trippelsdorf <markus@trippelsdorf.de> Cc: Alain Knaff <alain@knaff.lu> Cc: Albin Tonnerre <albin.tonnerre@free-electrons.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
168 lines
5.3 KiB
Text
168 lines
5.3 KiB
Text
#
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# Configuration for initramfs
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#
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config INITRAMFS_SOURCE
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string "Initramfs source file(s)"
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default ""
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help
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This can be either a single cpio archive with a .cpio suffix or a
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space-separated list of directories and files for building the
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initramfs image. A cpio archive should contain a filesystem archive
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to be used as an initramfs image. Directories should contain a
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filesystem layout to be included in the initramfs image. Files
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should contain entries according to the format described by the
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"usr/gen_init_cpio" program in the kernel tree.
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When multiple directories and files are specified then the
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initramfs image will be the aggregate of all of them.
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See <file:Documentation/early-userspace/README> for more details.
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If you are not sure, leave it blank.
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config INITRAMFS_ROOT_UID
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int "User ID to map to 0 (user root)"
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depends on INITRAMFS_SOURCE!=""
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default "0"
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help
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This setting is only meaningful if the INITRAMFS_SOURCE is
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contains a directory. Setting this user ID (UID) to something
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other than "0" will cause all files owned by that UID to be
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owned by user root in the initial ramdisk image.
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If you are not sure, leave it set to "0".
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config INITRAMFS_ROOT_GID
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int "Group ID to map to 0 (group root)"
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depends on INITRAMFS_SOURCE!=""
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default "0"
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help
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This setting is only meaningful if the INITRAMFS_SOURCE is
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contains a directory. Setting this group ID (GID) to something
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other than "0" will cause all files owned by that GID to be
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owned by group root in the initial ramdisk image.
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If you are not sure, leave it set to "0".
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config RD_GZIP
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bool "Support initial ramdisks compressed using gzip" if EXPERT
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default y
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depends on BLK_DEV_INITRD
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select DECOMPRESS_GZIP
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help
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Support loading of a gzip encoded initial ramdisk or cpio buffer.
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If unsure, say Y.
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config RD_BZIP2
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bool "Support initial ramdisks compressed using bzip2" if EXPERT
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default !EXPERT
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depends on BLK_DEV_INITRD
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select DECOMPRESS_BZIP2
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help
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Support loading of a bzip2 encoded initial ramdisk or cpio buffer
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If unsure, say N.
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config RD_LZMA
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bool "Support initial ramdisks compressed using LZMA" if EXPERT
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default !EXPERT
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depends on BLK_DEV_INITRD
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select DECOMPRESS_LZMA
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help
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Support loading of a LZMA encoded initial ramdisk or cpio buffer
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If unsure, say N.
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config RD_XZ
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bool "Support initial ramdisks compressed using XZ" if EXPERT
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default !EXPERT
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depends on BLK_DEV_INITRD
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select DECOMPRESS_XZ
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help
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Support loading of a XZ encoded initial ramdisk or cpio buffer.
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If unsure, say N.
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config RD_LZO
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bool "Support initial ramdisks compressed using LZO" if EXPERT
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default !EXPERT
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depends on BLK_DEV_INITRD
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select DECOMPRESS_LZO
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help
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Support loading of a LZO encoded initial ramdisk or cpio buffer
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If unsure, say N.
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choice
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prompt "Built-in initramfs compression mode" if INITRAMFS_SOURCE!=""
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help
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This option decides by which algorithm the builtin initramfs
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will be compressed. Several compression algorithms are
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available, which differ in efficiency, compression and
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decompression speed. Compression speed is only relevant
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when building a kernel. Decompression speed is relevant at
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each boot.
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If you have any problems with bzip2 or LZMA compressed
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initramfs, mail me (Alain Knaff) <alain@knaff.lu>.
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High compression options are mostly useful for users who are
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low on RAM, since it reduces the memory consumption during
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boot.
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If in doubt, select 'gzip'
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config INITRAMFS_COMPRESSION_NONE
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bool "None"
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help
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Do not compress the built-in initramfs at all. This may
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sound wasteful in space, but, you should be aware that the
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built-in initramfs will be compressed at a later stage
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anyways along with the rest of the kernel, on those
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architectures that support this.
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However, not compressing the initramfs may lead to slightly
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higher memory consumption during a short time at boot, while
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both the cpio image and the unpacked filesystem image will
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be present in memory simultaneously
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config INITRAMFS_COMPRESSION_GZIP
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bool "Gzip"
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depends on RD_GZIP
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help
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The old and tried gzip compression. It provides a good balance
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between compression ratio and decompression speed.
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config INITRAMFS_COMPRESSION_BZIP2
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bool "Bzip2"
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depends on RD_BZIP2
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help
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Its compression ratio and speed is intermediate.
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Decompression speed is slowest among the choices. The initramfs
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size is about 10% smaller with bzip2, in comparison to gzip.
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Bzip2 uses a large amount of memory. For modern kernels you
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will need at least 8MB RAM or more for booting.
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config INITRAMFS_COMPRESSION_LZMA
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bool "LZMA"
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depends on RD_LZMA
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help
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This algorithm's compression ratio is best.
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Decompression speed is between the other choices.
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Compression is slowest. The initramfs size is about 33%
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smaller with LZMA in comparison to gzip.
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config INITRAMFS_COMPRESSION_XZ
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bool "XZ"
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depends on RD_XZ
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help
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XZ uses the LZMA2 algorithm. The initramfs size is about 30%
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smaller with XZ in comparison to gzip. Decompression speed
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is better than that of bzip2 but worse than gzip and LZO.
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Compression is slow.
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config INITRAMFS_COMPRESSION_LZO
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bool "LZO"
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depends on RD_LZO
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help
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Its compression ratio is the poorest among the choices. The kernel
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size is about 10% bigger than gzip; however its speed
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(both compression and decompression) is the fastest.
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endchoice
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