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Commit 65a50c65 authored by Todd Brandt's avatar Todd Brandt Committed by Steven Rostedt (VMware)
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ftrace/graph: Add ftrace_graph_max_depth kernel parameter 

Early trace callgraphs can be extremely large on systems with
several seconds of boot time. The max_depth parameter limits how
deep the graph trace goes and reduces the output size. This
parameter is the same as the max_graph_depth file in tracefs.

Link: http://lkml.kernel.org/r/1488499935-23216-1-git-send-email-todd.e.brandt@linux.intel.com



Signed-off-by: default avatarTodd Brandt <todd.e.brandt@linux.intel.com>
[ changed comments about debugfs to tracefs ]
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent bf7165cf

Documentation/admin-guide/kernel-parameters.txt

+6 −0
Original line number Original line Diff line number Diff line
@@ -1173,6 +1173,12 @@ 
			functions that can be changed at run time by the

			functions that can be changed at run time by the

			set_graph_notrace file in the debugfs tracing directory.

			set_graph_notrace file in the debugfs tracing directory.





	ftrace_graph_max_depth=<uint>

			[FTRACE] Used with the function graph tracer. This is

			the max depth it will trace into a function. This value

			can be changed at run time by the max_graph_depth file

			in the tracefs tracing directory. default: 0 (no limit)



	gamecon.map[2|3]=

	gamecon.map[2|3]=

			[HW,JOY] Multisystem joystick and NES/SNES/PSX pad

			[HW,JOY] Multisystem joystick and NES/SNES/PSX pad

			support via parallel port (up to 5 devices per port)

			support via parallel port (up to 5 devices per port)

kernel/trace/ftrace.c

+9 −0
Original line number Original line Diff line number Diff line
@@ -4415,6 +4415,15 @@ static int __init set_graph_notrace_function(char *str) 
}

}

__setup("ftrace_graph_notrace=", set_graph_notrace_function);

__setup("ftrace_graph_notrace=", set_graph_notrace_function);





static int __init set_graph_max_depth_function(char *str)

{

	if (!str)

		return 0;

	fgraph_max_depth = simple_strtoul(str, NULL, 0);

	return 1;

}

__setup("ftrace_graph_max_depth=", set_graph_max_depth_function);



static void __init set_ftrace_early_graph(char *buf, int enable)

static void __init set_ftrace_early_graph(char *buf, int enable)

{

{

	int ret;

	int ret;