Introduce channel timer lock

Currently a shadow of the channel lock. Will eventually be used to
protect channel timer handler from concurrent channel updates without
being held when the timer is stopped (future commit).

Reviewed-by: Julien Desfossez <julien.desfossez@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Conflicts:
	src/common/consumer-stream.c

diff --git a/src/common/consumer-metadata-cache.c b/src/common/consumer-metadata-cache.c
index 4c8a665af0db7aa1d5d8224edcfac96c5fc2fbb2..e21fd4c73cb0b8c4b5d8990500c5d1188909a33e 100644 (file)
--- a/src/common/consumer-metadata-cache.c
+++ b/src/common/consumer-metadata-cache.c
@@ -210,6 +210,7 @@ int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
         */
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
        pthread_mutex_lock(&channel->metadata_cache->lock);
 
        if (cache->rb_pushed >= offset) {
@@ -230,6 +231,7 @@ int consumer_metadata_cache_flushed(struct lttng_consumer_channel *channel,
        }
 
        pthread_mutex_unlock(&channel->metadata_cache->lock);
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 

diff --git a/src/common/consumer.c b/src/common/consumer.c
index feeb9163bb89cf59e668571ef487ff81091e6fba..ce13a9835a0fa554facc474efd76a1dbff96313a 100644 (file)
--- a/src/common/consumer.c
+++ b/src/common/consumer.c
@@ -293,6 +293,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
 
        switch (consumer_data.type) {
        case LTTNG_CONSUMER_KERNEL:
@@ -322,6 +323,7 @@ void consumer_del_channel(struct lttng_consumer_channel *channel)
 
        call_rcu(&channel->node.head, free_channel_rcu);
 end:
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 }
@@ -655,6 +657,7 @@ static int add_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
+       pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
        rcu_read_lock();
 
@@ -698,6 +701,7 @@ static int add_stream(struct lttng_consumer_stream *stream,
 
        rcu_read_unlock();
        pthread_mutex_unlock(&stream->lock);
+       pthread_mutex_unlock(&stream->chan->timer_lock);
        pthread_mutex_unlock(&stream->chan->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -885,6 +889,7 @@ struct lttng_consumer_channel *consumer_allocate_channel(uint64_t key,
        channel->tracefile_size = tracefile_size;
        channel->tracefile_count = tracefile_count;
        pthread_mutex_init(&channel->lock, NULL);
+       pthread_mutex_init(&channel->timer_lock, NULL);
 
        strncpy(channel->pathname, pathname, sizeof(channel->pathname));
        channel->pathname[sizeof(channel->pathname) - 1] = '\0';
@@ -918,6 +923,7 @@ int consumer_add_channel(struct lttng_consumer_channel *channel,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
        rcu_read_lock();
 
        lttng_ht_lookup(consumer_data.channel_ht, &channel->key, &iter);
@@ -934,6 +940,7 @@ int consumer_add_channel(struct lttng_consumer_channel *channel,
 
 end:
        rcu_read_unlock();
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -1895,6 +1902,7 @@ void consumer_del_metadata_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
+       pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
 
        switch (consumer_data.type) {
@@ -1989,6 +1997,7 @@ end:
        stream->chan->metadata_stream = NULL;
 
        pthread_mutex_unlock(&stream->lock);
+       pthread_mutex_unlock(&stream->chan->timer_lock);
        pthread_mutex_unlock(&stream->chan->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 
@@ -2019,6 +2028,7 @@ static int add_metadata_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&stream->chan->lock);
+       pthread_mutex_lock(&stream->chan->timer_lock);
        pthread_mutex_lock(&stream->lock);
 
        /*
@@ -2071,6 +2081,7 @@ static int add_metadata_stream(struct lttng_consumer_stream *stream,
 
        pthread_mutex_unlock(&stream->lock);
        pthread_mutex_unlock(&stream->chan->lock);
+       pthread_mutex_unlock(&stream->chan->timer_lock);
        pthread_mutex_unlock(&consumer_data.lock);
        return ret;
 }

diff --git a/src/common/consumer.h b/src/common/consumer.h
index 8751f234e31605188294c809d9fef593a82d8198..a0b2a7efe5ef5861f3a06bf21e2589783a8cfffc 100644 (file)
--- a/src/common/consumer.h
+++ b/src/common/consumer.h
@@ -160,12 +160,29 @@ struct lttng_consumer_channel {
        /*
         * Channel lock.
         *
+        * This lock protects against concurrent update of channel.
+        *
         * This is nested INSIDE the consumer data lock.
+        * This is nested OUTSIDE the channel timer lock.
         * This is nested OUTSIDE the metadata cache lock.
         * This is nested OUTSIDE stream lock.
         * This is nested OUTSIDE consumer_relayd_sock_pair lock.
         */
        pthread_mutex_t lock;
+
+       /*
+        * Channel teardown lock.
+        *
+        * This lock protect against teardown of channel. It is _never_
+        * taken by the timer handler.
+        *
+        * This is nested INSIDE the consumer data lock.
+        * This is nested INSIDE the channel lock.
+        * This is nested OUTSIDE the metadata cache lock.
+        * This is nested OUTSIDE stream lock.
+        * This is nested OUTSIDE consumer_relayd_sock_pair lock.
+        */
+       pthread_mutex_t timer_lock;
 };
 
 /*
@@ -238,6 +255,7 @@ struct lttng_consumer_stream {
         * This is nested INSIDE the consumer_data lock.
         * This is nested INSIDE the metadata cache lock.
         * This is nested INSIDE the channel lock.
+        * This is nested INSIDE the channel timer lock.
         * This is nested OUTSIDE consumer_relayd_sock_pair lock.
         */
        pthread_mutex_t lock;

diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index 8926c1c1604e79968fa0364462c2529315b98857..f9d0817c2de5f44c217b71920fdf2d08f5ae6abc 100644 (file)
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -654,6 +654,7 @@ static int close_metadata(uint64_t chan_key)
 
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
 
        if (cds_lfht_is_node_deleted(&channel->node.node)) {
                goto error_unlock;
@@ -674,6 +675,7 @@ static int close_metadata(uint64_t chan_key)
        }
 
 error_unlock:
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);
 error:
@@ -779,6 +781,7 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
         */
        pthread_mutex_lock(&consumer_data.lock);
        pthread_mutex_lock(&channel->lock);
+       pthread_mutex_lock(&channel->timer_lock);
        pthread_mutex_lock(&channel->metadata_cache->lock);
        ret = consumer_metadata_cache_write(channel, offset, len, metadata_str);
        if (ret < 0) {
@@ -790,11 +793,13 @@ int lttng_ustconsumer_recv_metadata(int sock, uint64_t key, uint64_t offset,
                 * waiting for the metadata cache to be flushed.
                 */
                pthread_mutex_unlock(&channel->metadata_cache->lock);
+               pthread_mutex_unlock(&channel->timer_lock);
                pthread_mutex_unlock(&channel->lock);
                pthread_mutex_unlock(&consumer_data.lock);
                goto end_free;
        }
        pthread_mutex_unlock(&channel->metadata_cache->lock);
+       pthread_mutex_unlock(&channel->timer_lock);
        pthread_mutex_unlock(&channel->lock);
        pthread_mutex_unlock(&consumer_data.lock);