[RFC/PATCH 0/3] static keys for debugobjects

From: Stephen Boyd
Date: Fri Apr 06 2012 - 03:03:44 EST


Building in debugobjects support without enabling debugobjects
by default is useful in test scenarios where recompiling isn't
an option. Moving this interface to static keys/jump labels should
allow us to always have this code compiled in without worrying about
performance overhead when it's disabled.

RFC because I don't have any numbers to back this up and it's debug
code. I took a stab at using perf but I don't think the x86 machine
I was using had good enough stuff to see i-cache misses or things
like that. Hints on what to do to actually prove this is useful are
appreciated.

This is based on the perf/jump-labels branch in the tip tree:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/jump-labels

Stephen Boyd (3):
timer: Move debugobjects.h include to timer.c
init: Initialize jump_labels before early parameters
debugobjects: Use static keys for debug_objects_enabled

include/linux/debugobjects.h | 94 +++++++++++++++++++++++++++++++++++++-----
include/linux/timer.h | 1 -
init/main.c | 4 +-
kernel/timer.c | 1 +
lib/debugobjects.c | 73 ++++++++++++--------------------
5 files changed, 113 insertions(+), 60 deletions(-)

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