Mathieu Desnoyers wrote:
* Nils Carlson ([email protected]) wrote:
Nils Carlson wrote:
Changes since v1:
Add a nesting comment
Make the locking around the transport list more intelligent, give
it its own mutex.
Signed-off-by: Nils Carlson <[email protected]>
and merged. I'll continue trying to fix things here... I don't need fine
grained locking. But I think its reasonable that we can lock on a
per-trace basis eventually at least, so multiple different traces can be
modified simultaneously. We'll see how it goes though. No hurry.
OK. One thing to keep is mind is that the current UST versions have
strong cross-data-structure serialization dependencies between traces
and event ID assignment, which requires to serialize many operations all
across the place (e.g. start/stop traces and marker ID compaction). So I
would be really cautious about making the locking too fine-grained in
that area. (own lock for transport looks fine though)
This is all going to be cleaned up by the upcoming refactoring, because
we'll assign event IDs on a per-session and per-stream basis. Hurray! :)
Sounds good. I'm going to try to keep my work at quite a high level, not
digging much lower than the trace level. My goal is to cleanup tracectl
a bit more.
David: Has there been any progress on the session daemon? I could maybe
lend a hand there? I'd be happy to help in drafting an api if you want.
/Nils
Mathieu
/Nils
---
libust/tracer.c | 14 +++++++++-----
1 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/libust/tracer.c b/libust/tracer.c
index 100dec0..ffcc2e7 100644
--- a/libust/tracer.c
+++ b/libust/tracer.c
@@ -182,7 +182,8 @@ static enum ltt_channels get_channel_type_from_name(const
char *name)
//ust// }
static CDS_LIST_HEAD(ltt_transport_list);
-
+/* transport mutex, nests inside traces mutex (ltt_lock_traces) */
+static DEFINE_MUTEX(ltt_transport_mutex);
/**
* ltt_transport_register - LTT transport registration
* @transport: transport structure
@@ -204,9 +205,9 @@ void ltt_transport_register(struct ltt_transport *transport)
*/
//ust// vmalloc_sync_all();
- ltt_lock_traces();
+ pthread_mutex_lock(<t_transport_mutex);
cds_list_add_tail(&transport->node, <t_transport_list);
- ltt_unlock_traces();
+ pthread_mutex_unlock(<t_transport_mutex);
}
/**
@@ -215,9 +216,9 @@ void ltt_transport_register(struct ltt_transport *transport)
*/
void ltt_transport_unregister(struct ltt_transport *transport)
{
- ltt_lock_traces();
+ pthread_mutex_lock(<t_transport_mutex);
cds_list_del(&transport->node);
- ltt_unlock_traces();
+ pthread_mutex_unlock(<t_transport_mutex);
}
static inline int is_channel_overwrite(enum ltt_channels chan,
@@ -458,12 +459,15 @@ int ltt_trace_set_type(const char *trace_name, const char
*trace_type)
goto traces_error;
}
+ pthread_mutex_lock(<t_transport_mutex);
cds_list_for_each_entry(tran_iter, <t_transport_list, node) {
if (!strcmp(tran_iter->name, trace_type)) {
transport = tran_iter;
break;
}
}
+ pthread_mutex_unlock(<t_transport_mutex);
+
if (!transport) {
ERR("Transport %s is not present", trace_type);
err = -EINVAL;
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