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Message-Id: <dd0e9ae03f42f2e5934cc33bd8b44f08045c4ec2.1258580048.git.jbaron@redhat.com>
Date: Wed, 18 Nov 2009 17:43:49 -0500
From: Jason Baron <jbaron@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: mingo@...e.hu, mathieu.desnoyers@...ymtl.ca, hpa@...or.com,
tglx@...utronix.de, rostedt@...dmis.org, andi@...stfloor.org,
roland@...hat.com, rth@...hat.com, mhiramat@...hat.com
Subject: [RFC PATCH 6/6] jump label v3 - tracepoint support
Make use of the jump label infrastructure for tracepoints.
Signed-off-by: Jason Baron <jbaron@...hat.com>
---
include/linux/tracepoint.h | 35 +++++++++++++++++++----------------
kernel/module.c | 2 +-
kernel/tracepoint.c | 25 ++++++++++++++++++-------
3 files changed, 38 insertions(+), 24 deletions(-)
diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 2aac8a8..7c4e9cb 100644
--- a/include/linux/tracepoint.h
+++ b/include/linux/tracepoint.h
@@ -16,6 +16,7 @@
#include <linux/types.h>
#include <linux/rcupdate.h>
+#include <linux/jump_label.h>
struct module;
struct tracepoint;
@@ -63,20 +64,22 @@ struct tracepoint {
* not add unwanted padding between the beginning of the section and the
* structure. Force alignment to the same alignment as the section start.
*/
-#define DECLARE_TRACE(name, proto, args) \
- extern struct tracepoint __tracepoint_##name; \
- static inline void trace_##name(proto) \
- { \
- if (unlikely(__tracepoint_##name.state)) \
- __DO_TRACE(&__tracepoint_##name, \
- TP_PROTO(proto), TP_ARGS(args)); \
- } \
- static inline int register_trace_##name(void (*probe)(proto)) \
- { \
- return tracepoint_probe_register(#name, (void *)probe); \
- } \
- static inline int unregister_trace_##name(void (*probe)(proto)) \
- { \
+#define DECLARE_TRACE(name, proto, args) \
+ extern struct tracepoint __tracepoint_##name; \
+ static inline void trace_##name(proto) \
+ { \
+ JUMP_LABEL(name, do_trace, __tracepoint_##name.state); \
+ return; \
+do_trace: \
+ __DO_TRACE(&__tracepoint_##name, \
+ TP_PROTO(proto), TP_ARGS(args)); \
+ } \
+ static inline int register_trace_##name(void (*probe)(proto)) \
+ { \
+ return tracepoint_probe_register(#name, (void *)probe); \
+ } \
+ static inline int unregister_trace_##name(void (*probe)(proto)) \
+ { \
return tracepoint_probe_unregister(#name, (void *)probe);\
}
@@ -97,7 +100,7 @@ struct tracepoint {
EXPORT_SYMBOL(__tracepoint_##name)
extern void tracepoint_update_probe_range(struct tracepoint *begin,
- struct tracepoint *end);
+ struct tracepoint *end, void *data);
#else /* !CONFIG_TRACEPOINTS */
#define DECLARE_TRACE(name, proto, args) \
@@ -120,7 +123,7 @@ extern void tracepoint_update_probe_range(struct tracepoint *begin,
#define EXPORT_TRACEPOINT_SYMBOL(name)
static inline void tracepoint_update_probe_range(struct tracepoint *begin,
- struct tracepoint *end)
+ struct tracepoint *end, void *data)
{ }
#endif /* CONFIG_TRACEPOINTS */
#endif /* DECLARE_TRACE */
diff --git a/kernel/module.c b/kernel/module.c
index 6b8a754..7ceba66 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -3114,7 +3114,7 @@ void module_update_tracepoints(void)
list_for_each_entry(mod, &modules, list)
if (!mod->taints)
tracepoint_update_probe_range(mod->tracepoints,
- mod->tracepoints + mod->num_tracepoints);
+ mod->tracepoints + mod->num_tracepoints, mod);
mutex_unlock(&module_mutex);
}
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index cc89be5..d78f4b0 100644
--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -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[];
@@ -239,7 +240,7 @@ static inline void remove_tracepoint(struct tracepoint_entry *e)
* Sets the probe callback corresponding to one tracepoint.
*/
static void set_tracepoint(struct tracepoint_entry **entry,
- struct tracepoint *elem, int active)
+ struct tracepoint *elem, int active, void *data)
{
WARN_ON(strcmp((*entry)->name, elem->name) != 0);
@@ -256,6 +257,12 @@ static void set_tracepoint(struct tracepoint_entry **entry,
* is used.
*/
rcu_assign_pointer(elem->funcs, (*entry)->funcs);
+
+ if (!elem->state && active)
+ enable_jump_label(elem->name, data);
+ else if (elem->state && !active)
+ disable_jump_label(elem->name, data);
+
elem->state = active;
}
@@ -265,11 +272,14 @@ static void set_tracepoint(struct tracepoint_entry **entry,
* function insures that the original callback is not used anymore. This insured
* by preempt_disable around the call site.
*/
-static void disable_tracepoint(struct tracepoint *elem)
+static void disable_tracepoint(struct tracepoint *elem, void *data)
{
if (elem->unregfunc && elem->state)
elem->unregfunc();
+ if (elem->state)
+ disable_jump_label(elem->name, data);
+
elem->state = 0;
rcu_assign_pointer(elem->funcs, NULL);
}
@@ -282,7 +292,8 @@ static void disable_tracepoint(struct tracepoint *elem)
* Updates the probe callback corresponding to a range of tracepoints.
*/
void
-tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
+tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end,
+ void *data)
{
struct tracepoint *iter;
struct tracepoint_entry *mark_entry;
@@ -295,9 +306,9 @@ tracepoint_update_probe_range(struct tracepoint *begin, struct tracepoint *end)
mark_entry = get_tracepoint(iter->name);
if (mark_entry) {
set_tracepoint(&mark_entry, iter,
- !!mark_entry->refcount);
+ !!mark_entry->refcount, data);
} else {
- disable_tracepoint(iter);
+ disable_tracepoint(iter, data);
}
}
mutex_unlock(&tracepoints_mutex);
@@ -310,7 +321,7 @@ static void tracepoint_update_probes(void)
{
/* Core kernel tracepoints */
tracepoint_update_probe_range(__start___tracepoints,
- __stop___tracepoints);
+ __stop___tracepoints, NULL);
/* tracepoints in modules. */
module_update_tracepoints();
}
@@ -565,7 +576,7 @@ int tracepoint_module_notify(struct notifier_block *self,
case MODULE_STATE_COMING:
case MODULE_STATE_GOING:
tracepoint_update_probe_range(mod->tracepoints,
- mod->tracepoints + mod->num_tracepoints);
+ mod->tracepoints + mod->num_tracepoints, data);
break;
}
return 0;
--
1.6.5.1
--
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