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authorIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
committerIngo Molnar <mingo@elte.hu>2009-09-07 08:19:51 +0200
commita1922ed661ab2c1637d0b10cde933bd9cd33d965 (patch)
tree0f1777542b385ebefd30b3586d830fd8ed6fda5b /samples
parent75e33751ca8bbb72dd6f1a74d2810ddc8cbe4bdf (diff)
parentd28daf923ac5e4a0d7cecebae56f3e339189366b (diff)
downloadlinux-2.6.38-lt-ux500-a1922ed661ab2c1637d0b10cde933bd9cd33d965.tar.gz
Merge branch 'tracing/core' into tracing/hw-breakpoints
Conflicts: arch/Kconfig kernel/trace/trace.h Merge reason: resolve the conflicts, plus adopt to the new ring-buffer APIs. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'samples')
-rw-r--r--samples/trace_events/Makefile8
-rw-r--r--samples/trace_events/trace-events-sample.h56
2 files changed, 40 insertions, 24 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..f24ae370e51 100644
--- a/samples/trace_events/trace-events-sample.h
+++ b/samples/trace_events/trace-events-sample.h
@@ -1,4 +1,30 @@
/*
+ * If TRACE_SYSTEM is defined, that will be the directory created
+ * in the ftrace directory under /debugfs/tracing/events/<system>
+ *
+ * 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 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
+ *
+ * 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 trace-events-sample
+ *
+ * As we do an the bottom of this file.
+ *
+ * Notice that TRACE_SYSTEM should be defined outside of #if
+ * protection, just like TRACE_INCLUDE_FILE.
+ */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM sample
+
+/*
* Notice that this file is not protected like a normal header.
* We also must allow for rereading of this file. The
*
@@ -16,24 +42,6 @@
#include <linux/tracepoint.h>
/*
- * 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
- * TRACE_SYSTEM.h where TRACE_SYSTEM is what is defined here.
- *
- * If you want a different system than file name, you can override
- * the header name by defining TRACE_INCLUDE_FILE
- *
- * If this file was called, goofy.h, then we would define:
- *
- * #define TRACE_INCLUDE_FILE goofy
- *
- */
-#undef TRACE_SYSTEM
-#define TRACE_SYSTEM sample
-
-/*
* The TRACE_EVENT macro is broken up into 5 parts.
*
* name: name of the trace point. This is also how to enable the tracepoint.
@@ -99,13 +107,13 @@ 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 +123,8 @@ 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