From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Thu, 23 Jun 2011 20:57:39 +0000 (-0400)
Subject: Add wait quiescent ioctl
X-Git-Tag: v2.0-pre1~47
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=360f38ea4fee91e2403c03cb43841ef6769aaac7;p=lttng-modules.git

Add wait quiescent ioctl

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/ltt-debugfs-abi.c b/ltt-debugfs-abi.c
index aa8dc0f4..c6d9f602 100644
--- a/ltt-debugfs-abi.c
+++ b/ltt-debugfs-abi.c
@@ -196,6 +196,8 @@ long lttng_abi_add_context(struct file *file,
  *		Returns the LTTng kernel tracer version
  *	LTTNG_KERNEL_TRACEPOINT_LIST
  *		Returns a file descriptor listing available tracepoints
+ *	LTTNG_KERNEL_WAIT_QUIESCENT
+ *		Returns after all previously running probes have completed
  *
  * The returned session will be deleted when its file descriptor is closed.
  */
diff --git a/ltt-debugfs-abi.h b/ltt-debugfs-abi.h
index 8dc0fde9..e3a7160b 100644
--- a/ltt-debugfs-abi.h
+++ b/ltt-debugfs-abi.h
@@ -94,6 +94,7 @@ struct lttng_kernel_context {
 #define LTTNG_KERNEL_TRACER_VERSION		\
 	_IOR(0xF6, 0x41, struct lttng_kernel_tracer_version)
 #define LTTNG_KERNEL_TRACEPOINT_LIST		_IO(0xF6, 0x42)
+#define LTTNG_KERNEL_WAIT_QUIESCENT		_IO(0xF6, 0x43)
 
 /* Session FD ioctl */
 #define LTTNG_KERNEL_METADATA			\
diff --git a/ltt-events.c b/ltt-events.c
index 42d486c1..3457699f 100644
--- a/ltt-events.c
+++ b/ltt-events.c
@@ -34,8 +34,6 @@ int _ltt_event_metadata_statedump(struct ltt_session *session,
 static
 int _ltt_session_metadata_statedump(struct ltt_session *session);
 
-
-static
 void synchronize_trace(void)
 {
 	synchronize_sched();
@@ -108,12 +106,9 @@ int ltt_session_enable(struct ltt_session *session)
 
 	ACCESS_ONCE(session->active) = 1;
 	ACCESS_ONCE(session->been_active) = 1;
-	synchronize_trace();	/* Wait for in-flight events to complete */
 	ret = _ltt_session_metadata_statedump(session);
-	if (ret) {
+	if (ret)
 		ACCESS_ONCE(session->active) = 0;
-		synchronize_trace();	/* Wait for in-flight events to complete */
-	}
 end:
 	mutex_unlock(&sessions_mutex);
 	return ret;
@@ -129,7 +124,6 @@ int ltt_session_disable(struct ltt_session *session)
 		goto end;
 	}
 	ACCESS_ONCE(session->active) = 0;
-	synchronize_trace();	/* Wait for in-flight events to complete */
 end:
 	mutex_unlock(&sessions_mutex);
 	return ret;
diff --git a/ltt-events.h b/ltt-events.h
index f3536cec..4cb4919f 100644
--- a/ltt-events.h
+++ b/ltt-events.h
@@ -273,6 +273,7 @@ int ltt_event_disable(struct ltt_event *event);
 void ltt_transport_register(struct ltt_transport *transport);
 void ltt_transport_unregister(struct ltt_transport *transport);
 
+void synchronize_trace(void);
 int ltt_debugfs_abi_init(void);
 void ltt_debugfs_abi_exit(void);