ovsdb-cs: Add coverage for full batch events.

When many update notifications arrive in a short time, it may happen
that we only process the first 50 of them and have to wait until the
next iteration to pick them up.

Because previously, there was no way for an operator to observe how
often this happened, we add a coverage metric for this event.

Signed-off-by: Martin Morgenstern <martin.morgenstern@cloudandheat.com>
(cherry picked from commit cf5bdb1a443551116d99e59427ba81a27167bf4e)

Author: martinmo

lib/ovsdb-cs.c

@@ -20,6 +20,7 @@
 
 #include <errno.h>
 
+#include "coverage.h"
 #include "hash.h"
 #include "jsonrpc.h"
 #include "openvswitch/dynamic-string.h"
@@ -40,6 +41,8 @@
 
 VLOG_DEFINE_THIS_MODULE(ovsdb_cs);
 
+COVERAGE_DEFINE(ovsdb_cs_run_batch_full);
+
 /* Connection state machine.
  *
  * When a JSON-RPC session connects, the CS layer sends a "monitor_cond"
@@ -639,11 +642,13 @@ ovsdb_cs_run(struct ovsdb_cs *cs, struct ovs_list *events)
         }
     }
 
+    bool aborted = false;
     int ret;
     for (int i = 0; i < 50; i++) {
         struct jsonrpc_msg *msg = NULL;
         ret = jsonrpc_session_recv(cs->session, &msg);
         if (ret == EAGAIN) {
+            aborted = true;
             break;
         }
         /* Even if we would not block we might not receive a message for two
@@ -655,6 +660,11 @@ ovsdb_cs_run(struct ovsdb_cs *cs, struct ovs_list *events)
             jsonrpc_msg_destroy(msg);
         }
     }
+
+    if (!aborted) {
+        COVERAGE_INC(ovsdb_cs_run_batch_full);
+    }
+
     ovs_list_push_back_all(events, &cs->data.events);
 }