tracing: Add ref_data to function and fgraph tracer structs (8f768993) · Commits · 戴 / test

The selftest for function and function graph tracers are defined as __init, as they are only executed at boot up. The "tracer" structs that are associated to those tracers are not setup as __init as they are used after boot. To stop mismatch warnings, those structures need to be annotated with __ref_data. Currently, the tracer structures are defined to __read_mostly, as they do not really change. But in the future they should be converted to consts, but that will take a little work because they have a "next" pointer that gets updated when they are registered. That will have to wait till the next major release. Link: http://lkml.kernel.org/r/1373596735.17876.84.camel@gandalf.local.home Reported-by:

kbuild test robot <fengguang.wu@intel.com> Reported-by:

Chen Gang <gang.chen@asianux.com> Signed-off-by:

Steven Rostedt <rostedt@goodmis.org>

kernel/trace/trace.h

+9 −0

Original line number	Diff line number	Diff line
		@@ -680,6 +680,15 @@ extern int trace_selftest_startup_sched_switch(struct tracer *trace,
		struct trace_array *tr);
		extern int trace_selftest_startup_branch(struct tracer *trace,
		struct trace_array *tr);
		/*
		* Tracer data references selftest functions that only occur
		* on boot up. These can be __init functions. Thus, when selftests
		* are enabled, then the tracers need to reference __init functions.
		*/
		#define __tracer_data __refdata
		#else
		/* Tracers are seldom changed. Optimize when selftests are disabled. */
		#define __tracer_data __read_mostly
		#endif /* CONFIG_FTRACE_STARTUP_TEST */

		extern void head_page(struct trace_array_cpu data);

kernel/trace/trace_functions.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -199,7 +199,7 @@ static int func_set_flag(u32 old_flags, u32 bit, int set)
		return 0;
		}

		static struct tracer function_trace __read_mostly =
		static struct tracer function_trace __tracer_data =
		{
		.name = "function",
		.init = function_trace_init,

kernel/trace/trace_functions_graph.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1448,7 +1448,7 @@ static struct trace_event graph_trace_ret_event = {
		.funcs = &graph_functions
		};

		static struct tracer graph_trace __read_mostly = {
		static struct tracer graph_trace __tracer_data = {
		.name = "function_graph",
		.open = graph_trace_open,
		.pipe_open = graph_trace_open,

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