diff options
Diffstat (limited to 'samples/trace_events')
| -rw-r--r-- | samples/trace_events/Makefile | 8 | ||||
| -rw-r--r-- | samples/trace_events/trace-events-sample.h | 27 |
2 files changed, 24 insertions, 11 deletions
diff --git a/samples/trace_events/Makefile b/samples/trace_events/Makefile index 0d428dc6728..0f8d92120c4 100644 --- a/samples/trace_events/Makefile +++ b/samples/trace_events/Makefile @@ -1,6 +1,14 @@ # builds the trace events example kernel modules; # then to use one (as root): insmod <module_name.ko> +# If you include a trace header outside of include/trace/events +# then the file that does the #define CREATE_TRACE_POINTS must +# have that tracer file in its main search path. This is because +# define_trace.h will include it, and must be able to find it from +# the include/trace directory. +# +# Here trace-events-sample.c does the CREATE_TRACE_POINTS. +# CFLAGS_trace-events-sample.o := -I$(src) obj-$(CONFIG_SAMPLE_TRACE_EVENTS) += trace-events-sample.o diff --git a/samples/trace_events/trace-events-sample.h b/samples/trace_events/trace-events-sample.h index 128a897687c..9977a756fb3 100644 --- a/samples/trace_events/trace-events-sample.h +++ b/samples/trace_events/trace-events-sample.h @@ -19,16 +19,21 @@ * If TRACE_SYSTEM is defined, that will be the directory created * in the ftrace directory under /debugfs/tracing/events/<system> * - * The define_trace.h belowe will also look for a file name of + * The define_trace.h below will also look for a file name of * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here. + * In this case, it would look for sample.h * - * If you want a different system than file name, you can override - * the header name by defining TRACE_INCLUDE_FILE + * If the header name will be different than the system name + * (as in this case), then you can override the header name that + * define_trace.h will look up by defining TRACE_INCLUDE_FILE * - * If this file was called, goofy.h, then we would define: + * This file is called trace-events-sample.h but we want the system + * to be called "sample". Therefore we must define the name of this + * file: * - * #define TRACE_INCLUDE_FILE goofy + * #define TRACE_INCLUDE_FILE trace-events-sample * + * As we do an the bottom of this file. */ #undef TRACE_SYSTEM #define TRACE_SYSTEM sample @@ -99,13 +104,13 @@ TRACE_EVENT(foo_bar, * * #define TRACE_INCLUDE_PATH ../../samples/trace_events * - * But I chose to simply make it use the current directory and then in - * the Makefile I added: + * But the safest and easiest way to simply make it use the directory + * that the file is in is to add in the Makefile: * - * CFLAGS_trace-events-sample.o := -I$(PWD)/samples/trace_events/ + * CFLAGS_trace-events-sample.o := -I$(src) * * This will make sure the current path is part of the include - * structure for our file so that we can find it. + * structure for our file so that define_trace.h can find it. * * I could have made only the top level directory the include: * @@ -115,8 +120,8 @@ TRACE_EVENT(foo_bar, * * #define TRACE_INCLUDE_PATH samples/trace_events * - * But then if something defines "samples" or "trace_events" then we - * could risk that being converted too, and give us an unexpected + * But then if something defines "samples" or "trace_events" as a macro + * then we could risk that being converted too, and give us an unexpected * result. */ #undef TRACE_INCLUDE_PATH |