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author | Bertrand Jacquin <beber@meleeweb.net> | 2014-08-27 11:01:56 (GMT) |
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committer | Rusty Russell <rusty@rustcorp.com.au> | 2014-08-27 12:24:12 (GMT) |
commit | beb50df39e91745604ce3cb9dc6a503f39f4383d (patch) | |
tree | eaa6a996228eb532f56f46d1b5004a10062ac4fa /init/Kconfig | |
parent | 40e42f6a2596bbe757e561d4806fadd924f8c9fd (diff) | |
download | linux-beb50df39e91745604ce3cb9dc6a503f39f4383d.tar.xz |
kbuild: handle module compression while running 'make modules_install'.
Since module-init-tools (gzip) and kmod (gzip and xz) support compressed
modules, it could be useful to include a support for compressing modules
right after having them installed. Doing this in kbuild instead of per
distro can permit to make this kind of usage more generic.
This patch add a Kconfig entry to "Enable loadable module support" menu
and let you choose to compress using gzip (default) or xz.
Both gzip and xz does not used any extra -[1-9] option since Andi Kleen
and Rusty Russell prove no gain is made using them. gzip is called with -n
argument to avoid storing original filename inside compressed file, that
way we can save some more bytes.
On a v3.16 kernel, 'make allmodconfig' generated 4680 modules for a
total of 378MB (no strip, no sign, no compress), the following table
shows observed disk space gain based on the allmodconfig .config :
| time |
+-------------+-----------------+
| manual .ko | make | size | percent
| compression | modules_install | | gain
+-------------+-----------------+------+--------
- | | 18.61s | 378M |
GZIP | 3m16s | 3m37s | 102M | 73.41%
XZ | 5m22s | 5m39s | 77M | 79.83%
The gain for restricted environnement seems to be interesting while
uncompress can be time consuming but happens only while loading a module,
that is generally done only once.
This is fully compatible with signed modules while the signed module is
compressed. module-init-tools or kmod handles decompression
and provide to other layer the uncompressed but signed payload.
Reviewed-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Bertrand Jacquin <beber@meleeweb.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'init/Kconfig')
-rw-r--r-- | init/Kconfig | 43 |
1 files changed, 43 insertions, 0 deletions
diff --git a/init/Kconfig b/init/Kconfig index e84c642..4980925 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -1906,6 +1906,49 @@ config MODULE_SIG_HASH default "sha384" if MODULE_SIG_SHA384 default "sha512" if MODULE_SIG_SHA512 +config MODULE_COMPRESS + bool "Compress modules on installation" + depends on MODULES + help + This option compresses the kernel modules when 'make + modules_install' is run. + + The modules will be compressed either using gzip or xz depend on the + choice made in "Compression algorithm". + + module-init-tools has support for gzip format while kmod handle gzip + and xz compressed modules. + + When a kernel module is installed from outside of the main kernel + source and uses the Kbuild system for installing modules then that + kernel module will also be compressed when it is installed. + + This option provides little benefit when the modules are to be used inside + an initrd or initramfs, it generally is more efficient to compress the whole + initrd or initramfs instead. + + This is fully compatible with signed modules while the signed module is + compressed. module-init-tools or kmod handles decompression and provide to + other layer the uncompressed but signed payload. + +choice + prompt "Compression algorithm" + depends on MODULE_COMPRESS + default MODULE_COMPRESS_GZIP + help + This determines which sort of compression will be used during + 'make modules_install'. + + GZIP (default) and XZ are supported. + +config MODULE_COMPRESS_GZIP + bool "GZIP" + +config MODULE_COMPRESS_XZ + bool "XZ" + +endchoice + endif # MODULES config INIT_ALL_POSSIBLE |