[PATCH 3.14 014/140] tracepoint: Do not waste memory on mods with no tracepoints

Greg Kroah-Hartman
2014-05-29T05:39:58Z

From: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>

commit 7dec935a3aa04412cba2cebe1524ae0d34a30c24 upstream.

No reason to allocate tp_module structures for modules that have no
tracepoints. This just wastes memory.

Fixes: b75ef8b44b1c "Tracepoint: Dissociate from module mutex"
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
kernel/tracepoint.c | 6 ++++++
1 file changed, 6 insertions(+)

--- a/kernel/tracepoint.c
+++ b/kernel/tracepoint.c
@@ -641,6 +641,9 @@ static int tracepoint_module_coming(stru
struct tp_module *tp_mod, *iter;
int ret = 0;

+ if (!mod->num_tracepoints)
+ return 0;
+
/*
* We skip modules that taint the kernel, especially those with different
* module headers (for forced load), to make sure we don't cause a crash.
@@ -684,6 +687,9 @@ static int tracepoint_module_going(struc
{
struct tp_module *pos;

+ if (!mod->num_tracepoints)
+ return 0;
+
mutex_lock(&tracepoints_mutex);
tracepoint_update_probe_range(mod->tracepoints_ptrs,
mod->tracepoints_ptrs + mod->num_tracepoints);