From: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Date: Tue, 21 May 2019 23:44:30 +0000 (-0400)
Subject: Maintain a channel-per-session_id hash table in the consumers
X-Git-Tag: v2.12.0-rc1~578
X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=commitdiff_plain;h=5c3892a6b0083de585509b7c71b76068b2f110bc

Maintain a channel-per-session_id hash table in the consumers

Add and maintain an hash table indexed by `session_id` that allows the
consumer daemons to perform actions on a set of channels belonging to
a given session.

This hash table holds no ownership of the channels; it is merely an
"index" to the existing set of channels maintained in the channel_ht.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
---

diff --git a/src/common/consumer/consumer.c b/src/common/consumer/consumer.c
index c70d95a58..9d25d83a3 100644
--- a/src/common/consumer/consumer.c
+++ b/src/common/consumer/consumer.c
@@ -393,6 +393,10 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 	iter.iter.node = &channel->node.node;
 	ret = lttng_ht_del(consumer_data.channel_ht, &iter);
 	assert(!ret);
+
+	iter.iter.node = &channel->channels_by_session_id_ht_node.node;
+	ret = lttng_ht_del(consumer_data.channels_by_session_id_ht, &iter);
+	assert(!ret);
 	rcu_read_unlock();
 
 	call_rcu(&channel->node.head, free_channel_rcu);
@@ -1035,6 +1039,8 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
 	}
 
 	lttng_ht_node_init_u64(&channel->node, channel->key);
+	lttng_ht_node_init_u64(&channel->channels_by_session_id_ht_node,
+			channel->session_id);
 
 	channel->wait_fd = -1;
 
@@ -1067,6 +1073,8 @@ int consumer_add_channel(struct lttng_consumer_channel *channel,
 
 	rcu_read_lock();
 	lttng_ht_add_unique_u64(consumer_data.channel_ht, &channel->node);
+	lttng_ht_add_u64(consumer_data.channels_by_session_id_ht,
+			&channel->channels_by_session_id_ht_node);
 	rcu_read_unlock();
 
 	pthread_mutex_unlock(&channel->timer_lock);
@@ -1225,6 +1233,7 @@ void lttng_consumer_cleanup(void)
 	rcu_read_unlock();
 
 	lttng_ht_destroy(consumer_data.channel_ht);
+	lttng_ht_destroy(consumer_data.channels_by_session_id_ht);
 
 	cleanup_relayd_ht();
 
@@ -3423,6 +3432,12 @@ int lttng_consumer_init(void)
 		goto error;
 	}
 
+	consumer_data.channels_by_session_id_ht =
+			lttng_ht_new(0, LTTNG_HT_TYPE_U64);
+	if (!consumer_data.channels_by_session_id_ht) {
+		goto error;
+	}
+
 	consumer_data.relayd_ht = lttng_ht_new(0, LTTNG_HT_TYPE_U64);
 	if (!consumer_data.relayd_ht) {
 		goto error;
diff --git a/src/common/consumer/consumer.h b/src/common/consumer/consumer.h
index b940036f6..1c1d01de9 100644
--- a/src/common/consumer/consumer.h
+++ b/src/common/consumer/consumer.h
@@ -112,6 +112,8 @@ struct consumer_metadata_cache;
 struct lttng_consumer_channel {
 	/* HT node used for consumer_data.channel_ht */
 	struct lttng_ht_node_u64 node;
+	/* HT node used for consumer_data.channels_by_session_id_ht */
+	struct lttng_ht_node_u64 channels_by_session_id_ht_node;
 	/* Indexed key. Incremented value in the consumer. */
 	uint64_t key;
 	/* Number of streams referencing this channel */
@@ -621,6 +623,8 @@ struct lttng_consumer_global_data {
 
 	/* Channel hash table protected by consumer_data.lock. */
 	struct lttng_ht *channel_ht;
+	/* Channel hash table indexed by session id. */
+	struct lttng_ht *channels_by_session_id_ht;
 	/*
 	 * Flag specifying if the local array of FDs needs update in the
 	 * poll function. Protected by consumer_data.lock.