X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=4e000fbd167e294c6b9139b6b7bdd2cf0098d6f1;hp=13cbe2149de6852ed08e6532f6025ff3e382a103;hb=c8f59ee5fc11492ef472dc5cfd2fd2c4926b1787;hpb=e316aad5fbbe3782872083cb68dfdd58bccea811

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 13cbe2149..4e000fbd1 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -138,7 +138,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 	}
 	case LTTNG_CONSUMER_ADD_STREAM:
 	{
-		int fd;
+		int fd, stream_pipe;
 		struct consumer_relayd_sock_pair *relayd = NULL;
 		struct lttng_consumer_stream *new_stream;
 		int alloc_ret = 0;
@@ -168,6 +168,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 				msg.u.stream.gid,
 				msg.u.stream.net_index,
 				msg.u.stream.metadata_flag,
+				msg.u.stream.session_id,
 				&alloc_ret);
 		if (new_stream == NULL) {
 			switch (alloc_ret) {
@@ -224,27 +225,26 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 			}
 		}
 
-		/* Send stream to the metadata thread */
+		/* Get the right pipe where the stream will be sent. */
 		if (new_stream->metadata_flag) {
-			do {
-				ret = write(ctx->consumer_metadata_pipe[1], &new_stream,
-						sizeof(new_stream));
-			} while (ret < 0 && errno == EINTR);
-			if (ret < 0) {
-				PERROR("write metadata pipe");
-				consumer_del_stream(new_stream, NULL);
-			}
+			stream_pipe = ctx->consumer_metadata_pipe[1];
 		} else {
-			ret = consumer_add_stream(new_stream);
-			if (ret) {
-				ERR("Consumer add stream %d failed. Continuing",
-						new_stream->key);
-				consumer_del_stream(new_stream, NULL);
-				goto end_nosignal;
-			}
+			stream_pipe = ctx->consumer_data_pipe[1];
 		}
 
-		DBG("Kernel consumer_add_stream (%d)", fd);
+		do {
+			ret = write(stream_pipe, &new_stream, sizeof(new_stream));
+		} while (ret < 0 && errno == EINTR);
+		if (ret < 0) {
+			PERROR("Consumer write %s stream to pipe %d",
+					new_stream->metadata_flag ? "metadata" : "data",
+					stream_pipe);
+			consumer_del_stream(new_stream, NULL);
+			goto end_nosignal;
+		}
+
+		DBG("Kernel consumer ADD_STREAM %s (fd: %d) with relayd id %" PRIu64,
+				msg.u.stream.path_name, fd, new_stream->relayd_stream_id);
 		break;
 	}
 	case LTTNG_CONSUMER_UPDATE_STREAM:
@@ -280,24 +280,26 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
 		goto end_nosignal;
 	}
+	case LTTNG_CONSUMER_DATA_AVAILABLE:
+	{
+		int32_t ret;
+		uint64_t id = msg.u.data_available.session_id;
+
+		DBG("Kernel consumer data available command for id %" PRIu64, id);
+
+		ret = consumer_data_available(id);
+
+		/* Send back returned value to session daemon */
+		ret = lttcomm_send_unix_sock(sock, &ret, sizeof(ret));
+		if (ret < 0) {
+			PERROR("send data available ret code");
+		}
+		break;
+	}
 	default:
 		goto end_nosignal;
 	}
 
-	/*
-	 * Wake-up the other end by writing a null byte in the pipe (non-blocking).
-	 * Important note: Because writing into the pipe is non-blocking (and
-	 * therefore we allow dropping wakeup data, as long as there is wakeup data
-	 * present in the pipe buffer to wake up the other end), the other end
-	 * should perform the following sequence for waiting:
-	 *
-	 * 1) empty the pipe (reads).
-	 * 2) perform update operation.
-	 * 3) wait on the pipe (poll).
-	 */
-	do {
-		ret = write(ctx->consumer_poll_pipe[1], "", 1);
-	} while (ret < 0 && errno == EINTR);
 end_nosignal:
 	rcu_read_unlock();
 
@@ -481,3 +483,42 @@ error:
 	return ret;
 }
 
+/*
+ * Check if data is still being extracted from the buffers for a specific
+ * stream. Consumer data lock MUST be acquired before calling this function.
+ *
+ * Return 0 if the traced data are still getting read else 1 meaning that the
+ * data is available for trace viewer reading.
+ */
+int lttng_kconsumer_data_available(struct lttng_consumer_stream *stream)
+{
+	int ret;
+
+	assert(stream);
+
+	/*
+	 * Try to lock the stream mutex. On failure, we know that the stream is
+	 * being used else where hence there is data still being extracted.
+	 */
+	ret = pthread_mutex_trylock(&stream->lock);
+	if (ret == EBUSY) {
+		goto data_not_available;
+	}
+	/* The stream is now locked so we can do our ustctl calls */
+
+	ret = kernctl_get_next_subbuf(stream->wait_fd);
+	if (ret == 0) {
+		/* There is still data so let's put back this subbuffer. */
+		ret = kernctl_put_subbuf(stream->wait_fd);
+		assert(ret == 0);
+		pthread_mutex_unlock(&stream->lock);
+		goto data_not_available;
+	}
+
+	/* Data is available to be read for this stream. */
+	pthread_mutex_unlock(&stream->lock);
+	return 1;
+
+data_not_available:
+	return 0;
+}