linux/tools/perf/util/trigger.h
Wang Nan 3dcc4436fa perf tools: Introduce trigger class
Use 'trigger' to model operations which need to be executed when an
event (a signal, for example) is observed.

States and transits:

 OFF--(on)--> READY --(hit)--> HIT
		^               |
		|            (ready)
		|               |
		 \_____________/

is_hit and is_ready are two key functions to query the state of a
trigger. is_hit means the event already happen; is_ready means the
trigger is waiting for the event.

Signed-off-by: Wang Nan <wangnan0@huawei.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1461178794-40467-2-git-send-email-wangnan0@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2016-04-28 09:58:58 -03:00

95 lines
1.9 KiB
C

#ifndef __TRIGGER_H_
#define __TRIGGER_H_ 1
#include "util/debug.h"
#include "asm/bug.h"
/*
* Use trigger to model operations which need to be executed when
* an event (a signal, for example) is observed.
*
* States and transits:
*
*
* OFF--(on)--> READY --(hit)--> HIT
* ^ |
* | (ready)
* | |
* \_____________/
*
* is_hit and is_ready are two key functions to query the state of
* a trigger. is_hit means the event already happen; is_ready means the
* trigger is waiting for the event.
*/
struct trigger {
volatile enum {
TRIGGER_ERROR = -2,
TRIGGER_OFF = -1,
TRIGGER_READY = 0,
TRIGGER_HIT = 1,
} state;
const char *name;
};
#define TRIGGER_WARN_ONCE(t, exp) \
WARN_ONCE(t->state != exp, "trigger '%s' state transist error: %d in %s()\n", \
t->name, t->state, __func__)
static inline bool trigger_is_available(struct trigger *t)
{
return t->state >= 0;
}
static inline bool trigger_is_error(struct trigger *t)
{
return t->state <= TRIGGER_ERROR;
}
static inline void trigger_on(struct trigger *t)
{
TRIGGER_WARN_ONCE(t, TRIGGER_OFF);
t->state = TRIGGER_READY;
}
static inline void trigger_ready(struct trigger *t)
{
if (!trigger_is_available(t))
return;
t->state = TRIGGER_READY;
}
static inline void trigger_hit(struct trigger *t)
{
if (!trigger_is_available(t))
return;
TRIGGER_WARN_ONCE(t, TRIGGER_READY);
t->state = TRIGGER_HIT;
}
static inline void trigger_off(struct trigger *t)
{
if (!trigger_is_available(t))
return;
t->state = TRIGGER_OFF;
}
static inline void trigger_error(struct trigger *t)
{
t->state = TRIGGER_ERROR;
}
static inline bool trigger_is_ready(struct trigger *t)
{
return t->state == TRIGGER_READY;
}
static inline bool trigger_is_hit(struct trigger *t)
{
return t->state == TRIGGER_HIT;
}
#define DEFINE_TRIGGER(n) \
struct trigger n = {.state = TRIGGER_OFF, .name = #n}
#endif