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author | Albin Tonnerre <albin.tonnerre@free-electrons.com> | 2010-01-08 14:42:42 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-01-11 09:34:04 -0800 |
commit | 7dd65feb6c603e13eba501c34c662259ab38e70e (patch) | |
tree | 5ec4bf4ab09310dce796fc7a2067c18d76b4aa75 /lib/lzo/lzo1x_decompress.c | |
parent | ac4c2a3bbe5db5fc570b1d0ee1e474db7cb22585 (diff) | |
download | linux-7dd65feb6c603e13eba501c34c662259ab38e70e.tar.gz linux-7dd65feb6c603e13eba501c34c662259ab38e70e.tar.bz2 linux-7dd65feb6c603e13eba501c34c662259ab38e70e.zip |
lib: add support for LZO-compressed kernels
This patch series adds generic support for creating and extracting
LZO-compressed kernel images, as well as support for using such images on
the x86 and ARM architectures, and support for creating and using
LZO-compressed initrd and initramfs images.
Russell King said:
: Testing on a Cortex A9 model:
: - lzo decompressor is 65% of the time gzip takes to decompress a kernel
: - lzo kernel is 9% larger than a gzip kernel
:
: which I'm happy to say confirms your figures when comparing the two.
:
: However, when comparing your new gzip code to the old gzip code:
: - new is 99% of the size of the old code
: - new takes 42% of the time to decompress than the old code
:
: What this means is that for a proper comparison, the results get even better:
: - lzo is 7.5% larger than the old gzip'd kernel image
: - lzo takes 28% of the time that the old gzip code took
:
: So the expense seems definitely worth the effort. The only reason I
: can think of ever using gzip would be if you needed the additional
: compression (eg, because you have limited flash to store the image.)
:
: I would argue that the default for ARM should therefore be LZO.
This patch:
The lzo compressor is worse than gzip at compression, but faster at
extraction. Here are some figures for an ARM board I'm working on:
Uncompressed size: 3.24Mo
gzip 1.61Mo 0.72s
lzo 1.75Mo 0.48s
So for a compression ratio that is still relatively close to gzip, it's
much faster to extract, at least in that case.
This part contains:
- Makefile routine to support lzo compression
- Fixes to the existing lzo compressor so that it can be used in
compressed kernels
- wrapper around the existing lzo1x_decompress, as it only extracts one
block at a time, while we need to extract a whole file here
- config dialog for kernel compression
[akpm@linux-foundation.org: coding-style fixes]
[akpm@linux-foundation.org: cleanup]
Signed-off-by: Albin Tonnerre <albin.tonnerre@free-electrons.com>
Tested-by: Wu Zhangjin <wuzhangjin@gmail.com>
Acked-by: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Russell King <rmk@arm.linux.org.uk>
Acked-by: Russell King <rmk@arm.linux.org.uk>
Cc: Ralf Baechle <ralf@linux-mips.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/lzo/lzo1x_decompress.c')
-rw-r--r-- | lib/lzo/lzo1x_decompress.c | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/lib/lzo/lzo1x_decompress.c b/lib/lzo/lzo1x_decompress.c index 5dc6b29c1575..f2fd09850223 100644 --- a/lib/lzo/lzo1x_decompress.c +++ b/lib/lzo/lzo1x_decompress.c @@ -11,11 +11,13 @@ * Richard Purdie <rpurdie@openedhand.com> */ +#ifndef STATIC #include <linux/module.h> #include <linux/kernel.h> -#include <linux/lzo.h> -#include <asm/byteorder.h> +#endif + #include <asm/unaligned.h> +#include <linux/lzo.h> #include "lzodefs.h" #define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x)) @@ -244,9 +246,10 @@ lookbehind_overrun: *out_len = op - out; return LZO_E_LOOKBEHIND_OVERRUN; } - +#ifndef STATIC EXPORT_SYMBOL_GPL(lzo1x_decompress_safe); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("LZO1X Decompressor"); +#endif |