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authorMathieu Desnoyers <mathieu.desnoyers@polymtl.ca>2008-11-14 17:47:39 -0500
committerIngo Molnar <mingo@elte.hu>2008-11-16 09:01:29 +0100
commitc1df1bd2c4d4b20c83755a0f41956b57aec4842a (patch)
tree08761333b0850c6acfb31d72d7777dccc135ebde /kernel
parentmarkers: use module notifier (diff)
downloadlinux-dev-c1df1bd2c4d4b20c83755a0f41956b57aec4842a.tar.xz
linux-dev-c1df1bd2c4d4b20c83755a0f41956b57aec4842a.zip
markers: auto enable tracepoints (new API : trace_mark_tp())
Impact: new API Add a new API trace_mark_tp(), which declares a marker within a tracepoint probe. When the marker is activated, the tracepoint is automatically enabled. No branch test is used at the marker site, because it would be a duplicate of the branch already present in the tracepoint. Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/marker.c53
1 files changed, 51 insertions, 2 deletions
diff --git a/kernel/marker.c b/kernel/marker.c
index 348e70cc355a..c14ec26a9b9f 100644
--- a/kernel/marker.c
+++ b/kernel/marker.c
@@ -479,7 +479,7 @@ static int marker_set_format(struct marker_entry *entry, const char *format)
static int set_marker(struct marker_entry *entry, struct marker *elem,
int active)
{
- int ret;
+ int ret = 0;
WARN_ON(strcmp(entry->name, elem->name) != 0);
if (entry->format) {
@@ -531,9 +531,40 @@ static int set_marker(struct marker_entry *entry, struct marker *elem,
*/
smp_wmb();
elem->ptype = entry->ptype;
+
+ if (elem->tp_name && (active ^ elem->state)) {
+ WARN_ON(!elem->tp_cb);
+ /*
+ * It is ok to directly call the probe registration because type
+ * checking has been done in the __trace_mark_tp() macro.
+ */
+
+ if (active) {
+ /*
+ * try_module_get should always succeed because we hold
+ * lock_module() to get the tp_cb address.
+ */
+ ret = try_module_get(__module_text_address(
+ (unsigned long)elem->tp_cb));
+ BUG_ON(!ret);
+ ret = tracepoint_probe_register_noupdate(
+ elem->tp_name,
+ elem->tp_cb);
+ } else {
+ ret = tracepoint_probe_unregister_noupdate(
+ elem->tp_name,
+ elem->tp_cb);
+ /*
+ * tracepoint_probe_update_all() must be called
+ * before the module containing tp_cb is unloaded.
+ */
+ module_put(__module_text_address(
+ (unsigned long)elem->tp_cb));
+ }
+ }
elem->state = active;
- return 0;
+ return ret;
}
/*
@@ -544,7 +575,24 @@ static int set_marker(struct marker_entry *entry, struct marker *elem,
*/
static void disable_marker(struct marker *elem)
{
+ int ret;
+
/* leave "call" as is. It is known statically. */
+ if (elem->tp_name && elem->state) {
+ WARN_ON(!elem->tp_cb);
+ /*
+ * It is ok to directly call the probe registration because type
+ * checking has been done in the __trace_mark_tp() macro.
+ */
+ ret = tracepoint_probe_unregister_noupdate(elem->tp_name,
+ elem->tp_cb);
+ WARN_ON(ret);
+ /*
+ * tracepoint_probe_update_all() must be called
+ * before the module containing tp_cb is unloaded.
+ */
+ module_put(__module_text_address((unsigned long)elem->tp_cb));
+ }
elem->state = 0;
elem->single.func = __mark_empty_function;
/* Update the function before setting the ptype */
@@ -608,6 +656,7 @@ static void marker_update_probes(void)
marker_update_probe_range(__start___markers, __stop___markers);
/* Markers in modules. */
module_update_markers();
+ tracepoint_probe_update_all();
}
/**