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Commit 4ee7c60d authored by Steven Rostedt (VMware)'s avatar Steven Rostedt (VMware)
Browse files

init, tracing: Add initcall trace events 



Being able to trace the start and stop of initcalls is useful to see where
the timings are an issue. There is already an "initcall_debug" parameter,
but that can cause a large overhead itself, as the printing of the
information may take longer than the initcall functions.

Adding in a start and finish trace event around the initcall functions, as
well as a trace event that records the level of the initcalls, one can get a
much finer measurement of the times and interactions of the initcalls
themselves, as trace events are much lighter than printk()s.

Suggested-by: default avatarAbderrahmane Benbachir <abderrahmane.benbachir@polymtl.ca>
Signed-off-by: default avatarSteven Rostedt (VMware) <rostedt@goodmis.org>
parent 8ec8405f

include/trace/events/initcall.h

0 → 100644
+66 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#undef TRACE_SYSTEM

#define TRACE_SYSTEM initcall



#if !defined(_TRACE_INITCALL_H) || defined(TRACE_HEADER_MULTI_READ)

#define _TRACE_INITCALL_H



#include <linux/tracepoint.h>



TRACE_EVENT(initcall_level,



	TP_PROTO(const char *level),



	TP_ARGS(level),



	TP_STRUCT__entry(

		__string(level, level)

	),



	TP_fast_assign(

		__assign_str(level, level);

	),



	TP_printk("level=%s", __get_str(level))

);



TRACE_EVENT(initcall_start,



	TP_PROTO(initcall_t func),



	TP_ARGS(func),



	TP_STRUCT__entry(

		__field(initcall_t, func)

	),



	TP_fast_assign(

		__entry->func = func;

	),



	TP_printk("func=%pS", __entry->func)

);



TRACE_EVENT(initcall_finish,



	TP_PROTO(initcall_t func, int ret),



	TP_ARGS(func, ret),



	TP_STRUCT__entry(

		__field(initcall_t,	func)

		__field(int,		ret)

	),



	TP_fast_assign(

		__entry->func = func;

		__entry->ret = ret;

	),



	TP_printk("func=%pS ret=%d", __entry->func, __entry->ret)

);



#endif /* if !defined(_TRACE_GPIO_H) || defined(TRACE_HEADER_MULTI_READ) */



/* This part must be outside protection */

#include <trace/define_trace.h>

init/main.c

+7 −0
Original line number Diff line number Diff line
@@ -97,6 +97,9 @@ 
#include <asm/sections.h>

#include <asm/cacheflush.h>



#define CREATE_TRACE_POINTS

#include <trace/events/initcall.h>



static int kernel_init(void *);



extern void init_IRQ(void);
@@ -827,10 +830,12 @@ int __init_or_module do_one_initcall(initcall_t fn) 
	if (initcall_blacklisted(fn))

		return -EPERM;



	trace_initcall_start(fn);

	if (initcall_debug)

		ret = do_one_initcall_debug(fn);

	else

		ret = fn();

	trace_initcall_finish(fn, ret);



	msgbuf[0] = 0;
@@ -895,6 +900,7 @@ static void __init do_initcall_level(int level) 
		   level, level,

		   NULL, &repair_env_string);



	trace_initcall_level(initcall_level_names[level]);

	for (fn = initcall_levels[level]; fn < initcall_levels[level+1]; fn++)

		do_one_initcall(*fn);

}
@@ -929,6 +935,7 @@ static void __init do_pre_smp_initcalls(void) 
{

	initcall_t *fn;



	trace_initcall_level("early");

	for (fn = __initcall_start; fn < __initcall0_start; fn++)

		do_one_initcall(*fn);

}