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jump label: Tracepoint support for jump labels

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Make use of the jump label infrastructure for tracepoints.

Signed-off-by: Jason Baron <jbaron@redhat.com>
LKML-Reference: <a9ba2056e2c9cf332c3c300b577463ce66ff23a8.1284733808.git.jbaron@redhat.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
This commit is contained in:
Jason Baron 2010-09-17 11:09:13 -04:00 committed by Steven Rostedt
parent 4c3ef6d793
commit 8f7b50c514
2 changed files with 16 additions and 3 deletions
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5
include/linux/tracepoint.h
View file

@ -17,6 +17,7 @@
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/jump_label.h>
struct module;
struct tracepoint;
@ -145,7 +146,9 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
extern struct tracepoint __tracepoint_##name; \
static inline void trace_##name(proto) \
{ \
if (unlikely(__tracepoint_##name.state)) \
JUMP_LABEL(&__tracepoint_##name.state, do_trace); \
return; \
do_trace: \
__DO_TRACE(&__tracepoint_##name, \
TP_PROTO(data_proto), \
TP_ARGS(data_args)); \

14
kernel/tracepoint.c
View file

@ -25,6 +25,7 @@
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/jump_label.h>
extern struct tracepoint __start___tracepoints[];
extern struct tracepoint __stop___tracepoints[];
@ -263,7 +264,13 @@ static void set_tracepoint(struct tracepoint_entry **entry,
* is used.
*/
rcu_assign_pointer(elem->funcs, (*entry)->funcs);
elem->state = active;
if (!elem->state && active) {
enable_jump_label(&elem->state);
elem->state = active;
} else if (elem->state && !active) {
disable_jump_label(&elem->state);
elem->state = active;
}
}
/*
@ -277,7 +284,10 @@ static void disable_tracepoint(struct tracepoint *elem)
if (elem->unregfunc && elem->state)
elem->unregfunc();
elem->state = 0;
if (elem->state) {
disable_jump_label(&elem->state);
elem->state = 0;
}
rcu_assign_pointer(elem->funcs, NULL);
}