Fix consumer CPU hotplug support

This is a quick fix to handle stream update on CPU hotplug. Please look
at #ref 168 for more information and explanation on the real fix.

Signed-off-by: David Goulet <dgoulet@efficios.com>

diff --git a/src/common/consumer.c b/src/common/consumer.c
index d68bc5c2713eab333b80f9c7b196fa0b43de936c..f81de8d556a66149c75e59193c50a7d2c96741bd 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -298,11 +298,23 @@ end:
 int consumer_add_stream(struct lttng_consumer_stream *stream)
 {
        int ret = 0;
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
 
        pthread_mutex_lock(&consumer_data.lock);
        /* Steal stream identifier, for UST */
        consumer_steal_stream_key(stream->key);
        rcu_read_lock();
+
+       lttng_ht_lookup(consumer_data.stream_ht,
+                       (void *)((unsigned long) stream->key), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node != NULL) {
+               rcu_read_unlock();
+               /* Stream already exist. Ignore the insertion */
+               goto end;
+       }
+
        lttng_ht_add_unique_ulong(consumer_data.stream_ht, &stream->node);
        rcu_read_unlock();
        consumer_data.stream_count++;
@@ -466,11 +478,25 @@ end:
  */
 int consumer_add_channel(struct lttng_consumer_channel *channel)
 {
+       struct lttng_ht_node_ulong *node;
+       struct lttng_ht_iter iter;
+
        pthread_mutex_lock(&consumer_data.lock);
        /* Steal channel identifier, for UST */
        consumer_steal_channel_key(channel->key);
        rcu_read_lock();
+
+       lttng_ht_lookup(consumer_data.channel_ht,
+                       (void *)((unsigned long) channel->key), &iter);
+       node = lttng_ht_iter_get_node_ulong(&iter);
+       if (node != NULL) {
+               /* Channel already exist. Ignore the insertion */
+               goto end;
+       }
+
        lttng_ht_add_unique_ulong(consumer_data.channel_ht, &channel->node);
+
+end:
        rcu_read_unlock();
        pthread_mutex_unlock(&consumer_data.lock);