Prev: [PATCH 01/13] jump label v9: notifier atomic call chain notrace
Next: [PATCH 00/13] jump label v9
From: Jason Baron on 9 Jun 2010 17:40
Make use of the jump label infrastructure for tracepoints.

Signed-off-by: Jason Baron <jbaron(a)redhat.com>
---
include/linux/tracepoint.h | 8 ++++++--
kernel/tracepoint.c | 8 ++++++++
2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/linux/tracepoint.h b/include/linux/tracepoint.h
index 9a59d1f..883df16 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;
@@ -144,7 +145,9 @@ 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, do_trace, __tracepoint_##name.state);\
+ return; \
+do_trace: \
__DO_TRACE(&__tracepoint_##name, \
TP_PROTO(data_proto), \
TP_ARGS(data_args)); \
@@ -171,7 +174,8 @@ static inline void tracepoint_update_probe_range(struct tracepoint *begin,
__attribute__((section("__tracepoints_strings"))) = #name; \
struct tracepoint __tracepoint_##name \
__attribute__((section("__tracepoints"), aligned(32))) = \
- { __tpstrtab_##name, 0, reg, unreg, NULL }
+ { __tpstrtab_##name, 0, reg, unreg, NULL }; \
+ DEFINE_JUMP_LABEL(name);

#define DEFINE_TRACE(name) \
DEFINE_TRACE_FN(name, NULL, NULL);
diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c
index c77f3ec..b16d873 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[];
@@ -263,6 +264,10 @@ 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);
+ if (elem->state && !active)
+ disable_jump_label(elem->name);
elem->state = active;
}

@@ -277,6 +282,9 @@ static void disable_tracepoint(struct tracepoint *elem)
if (elem->unregfunc && elem->state)
elem->unregfunc();

+ if (elem->state)
+ disable_jump_label(elem->name);
+
elem->state = 0;
rcu_assign_pointer(elem->funcs, NULL);
}
--
1.7.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo(a)vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
 | 
Pages: 1
Prev: [PATCH 01/13] jump label v9: notifier atomic call chain notrace
Next: [PATCH 00/13] jump label v9