Commit 60602cb5 authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

fgraph: Make overruns 4 bytes in graph stack structure 



Inspecting the data structures of the function graph tracer, I found that
the overrun value is unsigned long, which is 8 bytes on a 64 bit machine,
and not only that, the depth is an int (4 bytes). The overrun can be simply
an unsigned int (4 bytes) and pack the ftrace_graph_ret structure better.

The depth is moved up next to the func, as it is used more often with func,
and improves cache locality.

Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 773c1670

include/linux/ftrace.h

+2 −2
Original line number Diff line number Diff line
@@ -864,11 +864,11 @@ struct ftrace_graph_ent { 
 */

struct ftrace_graph_ret {

	unsigned long func; /* Current function */

	int depth;

	/* Number of functions that overran the depth limit for current task */

	unsigned long overrun;

	unsigned int overrun;

	unsigned long long calltime;

	unsigned long long rettime;

	int depth;

} __packed;



/* Type of the callback handlers for tracing function graph*/

kernel/trace/trace_entries.h

+2 −2
Original line number Diff line number Diff line
@@ -93,10 +93,10 @@ FTRACE_ENTRY_PACKED(funcgraph_exit, ftrace_graph_ret_entry, 
	F_STRUCT(

		__field_struct(	struct ftrace_graph_ret,	ret	)

		__field_packed(	unsigned long,	ret,		func	)

		__field_packed(	unsigned long,	ret,		overrun	)

		__field_packed(	int,		ret,		depth	)

		__field_packed(	unsigned int,	ret,		overrun	)

		__field_packed(	unsigned long long, ret,	calltime)

		__field_packed(	unsigned long long, ret,	rettime	)

		__field_packed(	int,		ret,		depth	)

	),



	F_printk("<-- %ps (%d) (start: %llx  end: %llx) over: %d",

kernel/trace/trace_functions_graph.c

+1 −1
Original line number Diff line number Diff line
@@ -957,7 +957,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s, 


	/* Overrun */

	if (flags & TRACE_GRAPH_PRINT_OVERRUN)

		trace_seq_printf(s, " (Overruns: %lu)\n",

		trace_seq_printf(s, " (Overruns: %u)\n",

				 trace->overrun);



	print_graph_irq(iter, trace->func, TRACE_GRAPH_RET,

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