trace: provide mechanism for registering trace events
Remove the notion of there being a single global array
of trace events, by introducing a method for registering
groups of events.
The module_call_init() needs to be invoked at the start
of any program that wants to make use of the trace
support. Currently this covers system emulators qemu-nbd,
qemu-img and qemu-io.
[Squashed the following fix from Daniel P. Berrange
<berrange@redhat.com>:
linux-user/bsd-user: initialize trace events subsystem
The bsd-user/linux-user programs make use of the CPU emulation
code and this now requires that the trace events subsystem
is enabled, otherwise it'll crash trying to allocate an empty
trace events bitmap for the CPU object.
--Stefan]
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-14-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
diff --git a/trace/control.c b/trace/control.c
index 6b32511..a231327 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -29,6 +29,13 @@
int trace_events_enabled_count;
+typedef struct TraceEventGroup {
+ TraceEvent **events;
+} TraceEventGroup;
+
+static TraceEventGroup *event_groups;
+static size_t nevent_groups;
+
QemuOptsList qemu_trace_opts = {
.name = "trace",
.implied_opt_name = "enable",
@@ -50,6 +57,14 @@
};
+void trace_event_register_group(TraceEvent **events)
+{
+ event_groups = g_renew(TraceEventGroup, event_groups, nevent_groups + 1);
+ event_groups[nevent_groups].events = events;
+ nevent_groups++;
+}
+
+
TraceEvent *trace_event_name(const char *name)
{
assert(name != NULL);
@@ -100,14 +115,20 @@
void trace_event_iter_init(TraceEventIter *iter, const char *pattern)
{
iter->event = 0;
+ iter->group = 0;
iter->pattern = pattern;
}
TraceEvent *trace_event_iter_next(TraceEventIter *iter)
{
- while (trace_events[iter->event] != NULL) {
- TraceEvent *ev = trace_events[iter->event];
+ while (iter->group < nevent_groups &&
+ event_groups[iter->group].events[iter->event] != NULL) {
+ TraceEvent *ev = event_groups[iter->group].events[iter->event];
iter->event++;
+ if (event_groups[iter->group].events[iter->event] == NULL) {
+ iter->event = 0;
+ iter->group++;
+ }
if (!iter->pattern ||
pattern_glob(iter->pattern,
trace_event_get_name(ev))) {
