ovs-thread: Quiesce in xpthread_barrier_wait().

Otherwise the udpif revalidator threads can postpone RCU callbacks
essentially forever, especially if there are many revalidator threads and
little network traffic.

Reported-by: Alex Wang <alexw@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Alex Wang <alexw@nicira.com>

diff --git a/lib/ovs-thread.c b/lib/ovs-thread.c
index 3ca686f..f33f5f1 100644 (file)
--- a/lib/ovs-thread.c
+++ b/lib/ovs-thread.c
@@ -240,7 +240,10 @@ xpthread_barrier_wait(pthread_barrier_t *barrier)
 {
     int error;
 
 {
     int error;
 

+    ovsrcu_quiesce_start();

     error = pthread_barrier_wait(barrier);
     error = pthread_barrier_wait(barrier);

+    ovsrcu_quiesce_end();
+

     if (error && OVS_UNLIKELY(error != PTHREAD_BARRIER_SERIAL_THREAD)) {
         ovs_abort(error, "pthread_barrier_wait failed");
     }
     if (error && OVS_UNLIKELY(error != PTHREAD_BARRIER_SERIAL_THREAD)) {
         ovs_abort(error, "pthread_barrier_wait failed");
     }