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Commit 7e066fb8 authored by Mathieu Desnoyers's avatar Mathieu Desnoyers Committed by Ingo Molnar
Browse files

tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() 



Impact: API *CHANGE*. Must update all tracepoint users.

Add DEFINE_TRACE() to tracepoints to let them declare the tracepoint
structure in a single spot for all the kernel. It helps reducing memory
consumption, especially when declaring a lot of tracepoints, e.g. for
kmalloc tracing.

*API CHANGE WARNING*: now, DECLARE_TRACE() must be used in headers for
tracepoint declarations rather than DEFINE_TRACE(). This is the sane way
to do it. The name previously used was misleading.

Updates scheduler instrumentation to follow this API change.

Signed-off-by: default avatarMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 32f85742

Documentation/tracepoints.txt

+6 −1
Original line number Original line Diff line number Diff line
@@ -42,7 +42,7 @@ In include/trace/subsys.h : 




#include <linux/tracepoint.h>

#include <linux/tracepoint.h>





DEFINE_TRACE(subsys_eventname,

DECLARE_TRACE(subsys_eventname,

	TPPTOTO(int firstarg, struct task_struct *p),

	TPPTOTO(int firstarg, struct task_struct *p),

	TPARGS(firstarg, p));

	TPARGS(firstarg, p));
@@ -50,6 +50,8 @@ In subsys/file.c (where the tracing statement must be added) : 




#include <trace/subsys.h>

#include <trace/subsys.h>





DEFINE_TRACE(subsys_eventname);



void somefct(void)

void somefct(void)

{

{

	...

	...
@@ -86,6 +88,9 @@ to limit collisions. Tracepoint names are global to the kernel: they are 
considered as being the same whether they are in the core kernel image or in

considered as being the same whether they are in the core kernel image or in

modules.

modules.





If the tracepoint has to be used in kernel modules, an

EXPORT_TRACEPOINT_SYMBOL_GPL() or EXPORT_TRACEPOINT_SYMBOL() can be used to

export the defined tracepoints.





* Probe / tracepoint example

* Probe / tracepoint example

include/asm-generic/vmlinux.lds.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -71,6 +71,7 @@ 
	VMLINUX_SYMBOL(__start___markers) = .;				\

	VMLINUX_SYMBOL(__start___markers) = .;				\

	*(__markers)							\

	*(__markers)							\

	VMLINUX_SYMBOL(__stop___markers) = .;				\

	VMLINUX_SYMBOL(__stop___markers) = .;				\

	. = ALIGN(32);							\

	VMLINUX_SYMBOL(__start___tracepoints) = .;			\

	VMLINUX_SYMBOL(__start___tracepoints) = .;			\

	*(__tracepoints)						\

	*(__tracepoints)						\

	VMLINUX_SYMBOL(__stop___tracepoints) = .;			\

	VMLINUX_SYMBOL(__stop___tracepoints) = .;			\

include/linux/tracepoint.h

+25 −10
Original line number Original line Diff line number Diff line
@@ -24,8 +24,12 @@ struct tracepoint { 
	const char *name;		/* Tracepoint name */

	const char *name;		/* Tracepoint name */

	int state;			/* State. */

	int state;			/* State. */

	void **funcs;

	void **funcs;

} __attribute__((aligned(8)));

} __attribute__((aligned(32)));		/*



					 * Aligned on 32 bytes because it is

					 * globally visible and gcc happily

					 * align these on the structure size.

					 * Keep in sync with vmlinux.lds.h.

					 */





#define TPPROTO(args...)	args

#define TPPROTO(args...)	args

#define TPARGS(args...)		args

#define TPARGS(args...)		args
@@ -55,15 +59,10 @@ struct tracepoint { 
 * not add unwanted padding between the beginning of the section and the

 * not add unwanted padding between the beginning of the section and the

 * structure. Force alignment to the same alignment as the section start.

 * structure. Force alignment to the same alignment as the section start.

 */

 */

#define DEFINE_TRACE(name, proto, args)					\

#define DECLARE_TRACE(name, proto, args)				\

	extern struct tracepoint __tracepoint_##name;			\

	static inline void trace_##name(proto)				\

	static inline void trace_##name(proto)				\

	{								\

	{								\

		static const char __tpstrtab_##name[]			\

		__attribute__((section("__tracepoints_strings")))	\

		= #name;						\

		static struct tracepoint __tracepoint_##name		\

		__attribute__((section("__tracepoints"), aligned(8))) =	\

		{ __tpstrtab_##name, 0, NULL };				\

		if (unlikely(__tracepoint_##name.state))		\

		if (unlikely(__tracepoint_##name.state))		\

			__DO_TRACE(&__tracepoint_##name,		\

			__DO_TRACE(&__tracepoint_##name,		\

				TPPROTO(proto), TPARGS(args));		\

				TPPROTO(proto), TPARGS(args));		\
@@ -77,11 +76,23 @@ struct tracepoint { 
		return tracepoint_probe_unregister(#name, (void *)probe);\

		return tracepoint_probe_unregister(#name, (void *)probe);\

	}

	}





#define DEFINE_TRACE(name)						\

	static const char __tpstrtab_##name[]				\

	__attribute__((section("__tracepoints_strings"))) = #name;	\

	struct tracepoint __tracepoint_##name				\

	__attribute__((section("__tracepoints"), aligned(32))) =	\

		{ __tpstrtab_##name, 0, NULL }



#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)				\

	EXPORT_SYMBOL_GPL(__tracepoint_##name)

#define EXPORT_TRACEPOINT_SYMBOL(name)					\

	EXPORT_SYMBOL(__tracepoint_##name)



extern void tracepoint_update_probe_range(struct tracepoint *begin,

extern void tracepoint_update_probe_range(struct tracepoint *begin,

	struct tracepoint *end);

	struct tracepoint *end);





#else /* !CONFIG_TRACEPOINTS */

#else /* !CONFIG_TRACEPOINTS */

#define DEFINE_TRACE(name, proto, args)			\

#define DECLARE_TRACE(name, proto, args)				\

	static inline void _do_trace_##name(struct tracepoint *tp, proto) \

	static inline void _do_trace_##name(struct tracepoint *tp, proto) \

	{ }								\

	{ }								\

	static inline void trace_##name(proto)				\

	static inline void trace_##name(proto)				\
@@ -95,6 +106,10 @@ extern void tracepoint_update_probe_range(struct tracepoint *begin, 
		return -ENOSYS;						\

		return -ENOSYS;						\

	}

	}





#define DEFINE_TRACE(name)

#define EXPORT_TRACEPOINT_SYMBOL_GPL(name)

#define EXPORT_TRACEPOINT_SYMBOL(name)



static inline void tracepoint_update_probe_range(struct tracepoint *begin,

static inline void tracepoint_update_probe_range(struct tracepoint *begin,

	struct tracepoint *end)

	struct tracepoint *end)

{ }

{ }

include/trace/sched.h

+12 −12
Original line number Original line Diff line number Diff line
@@ -4,52 +4,52 @@ 
#include <linux/sched.h>

#include <linux/sched.h>

#include <linux/tracepoint.h>

#include <linux/tracepoint.h>





DEFINE_TRACE(sched_kthread_stop,

DECLARE_TRACE(sched_kthread_stop,

	TPPROTO(struct task_struct *t),

	TPPROTO(struct task_struct *t),

		TPARGS(t));

		TPARGS(t));





DEFINE_TRACE(sched_kthread_stop_ret,

DECLARE_TRACE(sched_kthread_stop_ret,

	TPPROTO(int ret),

	TPPROTO(int ret),

		TPARGS(ret));

		TPARGS(ret));





DEFINE_TRACE(sched_wait_task,

DECLARE_TRACE(sched_wait_task,

	TPPROTO(struct rq *rq, struct task_struct *p),

	TPPROTO(struct rq *rq, struct task_struct *p),

		TPARGS(rq, p));

		TPARGS(rq, p));





DEFINE_TRACE(sched_wakeup,

DECLARE_TRACE(sched_wakeup,

	TPPROTO(struct rq *rq, struct task_struct *p),

	TPPROTO(struct rq *rq, struct task_struct *p),

		TPARGS(rq, p));

		TPARGS(rq, p));





DEFINE_TRACE(sched_wakeup_new,

DECLARE_TRACE(sched_wakeup_new,

	TPPROTO(struct rq *rq, struct task_struct *p),

	TPPROTO(struct rq *rq, struct task_struct *p),

		TPARGS(rq, p));

		TPARGS(rq, p));





DEFINE_TRACE(sched_switch,

DECLARE_TRACE(sched_switch,

	TPPROTO(struct rq *rq, struct task_struct *prev,

	TPPROTO(struct rq *rq, struct task_struct *prev,

		struct task_struct *next),

		struct task_struct *next),

		TPARGS(rq, prev, next));

		TPARGS(rq, prev, next));





DEFINE_TRACE(sched_migrate_task,

DECLARE_TRACE(sched_migrate_task,

	TPPROTO(struct rq *rq, struct task_struct *p, int dest_cpu),

	TPPROTO(struct rq *rq, struct task_struct *p, int dest_cpu),

		TPARGS(rq, p, dest_cpu));

		TPARGS(rq, p, dest_cpu));





DEFINE_TRACE(sched_process_free,

DECLARE_TRACE(sched_process_free,

	TPPROTO(struct task_struct *p),

	TPPROTO(struct task_struct *p),

		TPARGS(p));

		TPARGS(p));





DEFINE_TRACE(sched_process_exit,

DECLARE_TRACE(sched_process_exit,

	TPPROTO(struct task_struct *p),

	TPPROTO(struct task_struct *p),

		TPARGS(p));

		TPARGS(p));





DEFINE_TRACE(sched_process_wait,

DECLARE_TRACE(sched_process_wait,

	TPPROTO(struct pid *pid),

	TPPROTO(struct pid *pid),

		TPARGS(pid));

		TPARGS(pid));





DEFINE_TRACE(sched_process_fork,

DECLARE_TRACE(sched_process_fork,

	TPPROTO(struct task_struct *parent, struct task_struct *child),

	TPPROTO(struct task_struct *parent, struct task_struct *child),

		TPARGS(parent, child));

		TPARGS(parent, child));





DEFINE_TRACE(sched_signal_send,

DECLARE_TRACE(sched_signal_send,

	TPPROTO(int sig, struct task_struct *p),

	TPPROTO(int sig, struct task_struct *p),

		TPARGS(sig, p));

		TPARGS(sig, p));

kernel/exit.c

+4 −0
Original line number Original line Diff line number Diff line
@@ -54,6 +54,10 @@ 
#include <asm/pgtable.h>

#include <asm/pgtable.h>

#include <asm/mmu_context.h>

#include <asm/mmu_context.h>





DEFINE_TRACE(sched_process_free);

DEFINE_TRACE(sched_process_exit);

DEFINE_TRACE(sched_process_wait);



static void exit_mm(struct task_struct * tsk);

static void exit_mm(struct task_struct * tsk);





static inline int task_detached(struct task_struct *p)

static inline int task_detached(struct task_struct *p)