jump label: 2.6.38 updates

Hi,

The first patch uses the storage space of the jump label key address as a pointer into the update table. In this way, we can find all the addresses that need to be updated without hashing.

The second patch introduces:

static __always_inline bool static_branch(struct jump_label_key *key);

instead of the old JUMP_LABEL(key, label) macro.

In this way, jump labels become really easy to use:

Define:

        struct jump_label_key jump_key;

Can be used as:

if (static_branch(&jump_key))
do unlikely code

enable/disale via:

        jump_label_enable(&jump_key);
        jump_label_disable(&jump_key);

that's it!

For perf, which also uses jump labels, I've left the reference counting out of the jump label layer, thus removing the 'jump_label_inc()' and 'jump_label_dec()' interface. Hopefully, this is a more palatable solution.

Thanks to H. Peter Anvin for suggesting the simpler 'static_branch()' function.

thanks,

-Jason

Jason Baron (2):
jump label: make enable/disable o(1)
jump label: introduce unlikely_switch()

 arch/sparc/include/asm/jump_label.h |   25 ++++---
 arch/x86/include/asm/jump_label.h   |   22 ++++---
 arch/x86/kernel/jump_label.c        |    2 +-
 include/linux/dynamic_debug.h       |   24 ++-----
 include/linux/jump_label.h          |   66 ++++++++++--------
 include/linux/jump_label_ref.h      |   36 +++-------
 include/linux/perf_event.h          |   28 ++++----
 include/linux/tracepoint.h          |    8 +--
 kernel/jump_label.c                 |  129 +++++++++++++++++++++++++++--------
 kernel/perf_event.c                 |   24 ++++--
 kernel/tracepoint.c                 |   22 ++----
 11 files changed, 226 insertions(+), 160 deletions(-)