Relay buffer-only channels and its prereqs (resubmit 2)

Hello everybody,

The changes since last submission are:
- Removed the git unignore stuff as it has been already merged.
- Fully converted all users to the new early_initcall() interface.
- Fixed patch 3 so that it works without locking the per-CPU buffer.
- Modified patch 3 as Pekka Enberg suggested.

Vegard Nossum expressed his interest in the first patch. However, he suggested naming these initcalls 'pre-SMP' rather than 'early' ('early' as in CPU hotplug docs and as they are now), suggesting the name should reflect usage. Please pitch in and comment about this.

Also, please review and comment/(n)ack/ask on/about these patches.

Eduard - Gabriel Munteanu (3):
Better interface for hooking early initcalls.
Full conversion to early_initcall() interface, remove old interface.
relay: Add buffer-only channels; useful for early logging.

 Documentation/filesystems/relay.txt |   11 +++
 include/asm-generic/vmlinux.lds.h   |    2 +
 include/linux/init.h                |    7 ++
 include/linux/relay.h               |    5 +
 include/linux/sched.h               |    9 --
 init/main.c                         |   21 +----
 kernel/relay.c                      |  170 +++++++++++++++++++++++++++++------
 kernel/sched.c                      |    6 +-
 kernel/softirq.c                    |    4 +-
 kernel/softlockup.c                 |   27 +++++-
 10 files changed, 203 insertions(+), 59 deletions(-)