[lttng-dev] [PATCH lttng-tools 4/4] Change the metadata hash table node

[David Goulet]

Oh forgot to reply :P

Yes... my bad. Present... the patch does what's described :)

David

Mathieu Desnoyers:
> * David Goulet (dgoulet at efficios.com) wrote:
>> Remove the use of the "waitfd_node" for metadata and index the "node" by
>> wait fd during stream allocation only for metadata stream.
>>
>> This was done so the waitfd node could be used later on for the hash
>> table indexing stream by session id the traced data check command (soon
>> to be implemented).
> 
> this last changelog paragraph, being using "was" (past) is confusing me.
> Is it what you are now doing (present) or what was there before that you
> are changing ?
> 
> Thanks,
> 
> Mathieu
> 
>>
>> Signed-off-by: David Goulet <dgoulet at efficios.com>
>> ---
>>  src/common/consumer.c |   36 +++++++++++++++++-------------------
>>  1 file changed, 17 insertions(+), 19 deletions(-)
>>
>> diff --git a/src/common/consumer.c b/src/common/consumer.c
>> index 1fb9960..0c1a812 100644
>> --- a/src/common/consumer.c
>> +++ b/src/common/consumer.c
>> @@ -172,17 +172,6 @@ void consumer_free_stream(struct rcu_head *head)
>>  	free(stream);
>>  }
>>  
>> -static
>> -void consumer_free_metadata_stream(struct rcu_head *head)
>> -{
>> -	struct lttng_ht_node_ulong *node =
>> -		caa_container_of(head, struct lttng_ht_node_ulong, head);
>> -	struct lttng_consumer_stream *stream =
>> -		caa_container_of(node, struct lttng_consumer_stream, waitfd_node);
>> -
>> -	free(stream);
>> -}
>> -
>>  /*
>>   * RCU protected relayd socket pair free.
>>   */
>> @@ -417,8 +406,17 @@ struct lttng_consumer_stream *consumer_allocate_stream(
>>  	stream->metadata_flag = metadata_flag;
>>  	strncpy(stream->path_name, path_name, sizeof(stream->path_name));
>>  	stream->path_name[sizeof(stream->path_name) - 1] = '\0';
>> -	lttng_ht_node_init_ulong(&stream->waitfd_node, stream->wait_fd);
>> -	lttng_ht_node_init_ulong(&stream->node, stream->key);
>> +
>> +	/*
>> +	 * Index differently the metadata node because the thread is using an
>> +	 * internal hash table to match streams in the metadata_ht to the epoll set
>> +	 * file descriptor.
>> +	 */
>> +	if (metadata_flag) {
>> +		lttng_ht_node_init_ulong(&stream->node, stream->wait_fd);
>> +	} else {
>> +		lttng_ht_node_init_ulong(&stream->node, stream->key);
>> +	}
>>  
>>  	/*
>>  	 * The cpu number is needed before using any ustctl_* actions. Ignored for
>> @@ -1578,11 +1576,11 @@ static void destroy_stream_ht(struct lttng_ht *ht)
>>  	}
>>  
>>  	rcu_read_lock();
>> -	cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, waitfd_node.node) {
>> +	cds_lfht_for_each_entry(ht->ht, &iter.iter, stream, node.node) {
>>  		ret = lttng_ht_del(ht, &iter);
>>  		assert(!ret);
>>  
>> -		call_rcu(&stream->waitfd_node.head, consumer_free_metadata_stream);
>> +		call_rcu(&stream->node.head, consumer_free_stream);
>>  	}
>>  	rcu_read_unlock();
>>  
>> @@ -1636,7 +1634,7 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
>>  	}
>>  
>>  	rcu_read_lock();
>> -	iter.iter.node = &stream->waitfd_node.node;
>> +	iter.iter.node = &stream->node.node;
>>  	ret = lttng_ht_del(ht, &iter);
>>  	assert(!ret);
>>  	rcu_read_unlock();
>> @@ -1707,7 +1705,7 @@ end:
>>  	}
>>  
>>  free_stream:
>> -	call_rcu(&stream->waitfd_node.head, consumer_free_metadata_stream);
>> +	call_rcu(&stream->node.head, consumer_free_stream);
>>  }
>>  
>>  /*
>> @@ -1756,7 +1754,7 @@ static int consumer_add_metadata_stream(struct lttng_consumer_stream *stream,
>>  	/* Steal stream identifier to avoid having streams with the same key */
>>  	consumer_steal_stream_key(stream->key, ht);
>>  
>> -	lttng_ht_add_unique_ulong(ht, &stream->waitfd_node);
>> +	lttng_ht_add_unique_ulong(ht, &stream->node);
>>  	rcu_read_unlock();
>>  
>>  	pthread_mutex_unlock(&consumer_data.lock);
>> @@ -1881,7 +1879,7 @@ restart:
>>  			assert(node);
>>  
>>  			stream = caa_container_of(node, struct lttng_consumer_stream,
>> -					waitfd_node);
>> +					node);
>>  
>>  			/* Check for error event */
>>  			if (revents & (LPOLLERR | LPOLLHUP)) {
>> -- 
>> 1.7.10.4
>>
>>
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>