linux/init
Bertrand Jacquin beb50df39e 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>
2014-08-27 21:54:12 +09:30
..
calibrate.c kernel: add calibration_delay_done() 2014-06-16 12:47:39 -06:00
do_mounts_initrd.c usermodehelper: split remaining calls to call_usermodehelper_fns() 2013-04-30 17:04:06 -07:00
do_mounts_md.c init: disable sparse checking of the mount.o source files 2012-05-31 17:49:27 -07:00
do_mounts_rd.c initramfs: support initramfs that is bigger than 2GiB 2014-08-08 15:57:26 -07:00
do_mounts.c init: make rootdelay=N consistent with rootwait behaviour 2014-08-08 15:57:18 -07:00
do_mounts.h
init_task.c sched/rt: Move rt specific bits into new header file 2013-02-07 20:51:08 +01:00
initramfs.c initramfs: add write error checks 2014-08-08 15:57:26 -07:00
Kconfig kbuild: handle module compression while running 'make modules_install'. 2014-08-27 21:54:12 +09:30
main.c init/main.c: code clean-up 2014-08-08 15:57:27 -07:00
Makefile init_task: Replace CONFIG_HAVE_GENERIC_INIT_TASK 2012-05-05 13:00:46 +02:00
noinitramfs.c init: mark __user address space on string literals 2010-10-26 16:52:15 -07:00
version.c proc: Split the namespace stuff out into linux/proc_ns.h 2013-05-01 17:29:39 -04:00