diff options
| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-26 09:19:02 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-26 09:19:02 -0700 |
| commit | e58b9a25eeb89ab2ee05cd093f6d7bc2f34acb21 (patch) | |
| tree | 40162c796bc60f00d062b37718dc62adc970ac07 /kernel/trace/Kconfig | |
| parent | a6025a2a861845447adeb7a11c3043039959d3a1 (diff) | |
| parent | df8c3dbee9e6f19ddb0ae8e05cdf76eb2d3b7f00 (diff) | |
Merge tag 'arizona-extcon-asoc' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc into char-misc-next
Mark writes:
ASoC/extcon: arizona: Fix interaction between HPDET and headphone outputs
This patch series covers both ASoC and extcon subsystems and fixes an
interaction between the HPDET function and the headphone outputs - we
really shouldn't run HPDET while the headphone is active. The first
patch is a refactoring to make the extcon side easier.
Diffstat (limited to 'kernel/trace/Kconfig')
| -rw-r--r-- | kernel/trace/Kconfig | 24 |
1 files changed, 14 insertions, 10 deletions
diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig index 192473b2279..fc382d6e276 100644 --- a/kernel/trace/Kconfig +++ b/kernel/trace/Kconfig @@ -414,24 +414,28 @@ config PROBE_EVENTS def_bool n config DYNAMIC_FTRACE - bool "enable/disable ftrace tracepoints dynamically" + bool "enable/disable function tracing dynamically" depends on FUNCTION_TRACER depends on HAVE_DYNAMIC_FTRACE default y help - This option will modify all the calls to ftrace dynamically - (will patch them out of the binary image and replace them - with a No-Op instruction) as they are called. A table is - created to dynamically enable them again. + This option will modify all the calls to function tracing + dynamically (will patch them out of the binary image and + replace them with a No-Op instruction) on boot up. During + compile time, a table is made of all the locations that ftrace + can function trace, and this table is linked into the kernel + image. When this is enabled, functions can be individually + enabled, and the functions not enabled will not affect + performance of the system. + + See the files in /sys/kernel/debug/tracing: + available_filter_functions + set_ftrace_filter + set_ftrace_notrace This way a CONFIG_FUNCTION_TRACER kernel is slightly larger, but otherwise has native performance as long as no tracing is active. - The changes to the code are done by a kernel thread that - wakes up once a second and checks to see if any ftrace calls - were made. If so, it runs stop_machine (stops all CPUS) - and modifies the code to jump over the call to ftrace. - config DYNAMIC_FTRACE_WITH_REGS def_bool y depends on DYNAMIC_FTRACE |