Fix: add consumer wake up pipe to avoid race

[lttng-tools.git] / src / common / consumer.h

diff --git a/src/common/consumer.h b/src/common/consumer.h
index 7485e65b259d4b855c301405425225a462b5e0bf..4ac823c017d03754ed545a9a1288df707b84778f 100644 (file)
--- a/src/common/consumer.h
+++ b/src/common/consumer.h
@@ -341,6 +341,9 @@ struct lttng_consumer_stream {
         */
        pthread_cond_t metadata_rdv;
        pthread_mutex_t metadata_rdv_lock;
+
+       /* Indicate if the stream still has some data to be read. */
+       unsigned int has_data:1;
 };
 
 /*
@@ -453,6 +456,19 @@ struct lttng_consumer_local_data {
        int consumer_splice_metadata_pipe[2];
        /* Data stream poll thread pipe. To transfer data stream to the thread */
        struct lttng_pipe *consumer_data_pipe;
+
+       /*
+        * Data thread use that pipe to catch wakeup from read subbuffer that
+        * detects that there is still data to be read for the stream encountered.
+        * Before doing so, the stream is flagged to indicate that there is still
+        * data to be read.
+        *
+        * Both pipes (read/write) are owned and used inside the data thread.
+        */
+       struct lttng_pipe *consumer_wakeup_pipe;
+       /* Indicate if the wakeup thread has been notified. */
+       unsigned int has_wakeup:1;
+
        /* to let the signal handler wake up the fd receiver thread */
        int consumer_should_quit[2];
        /* Metadata poll thread pipe. Transfer metadata stream to it */