Until now, the jsonrpc module has used messages received from the
remote peer as the sole means to determine that the JSON-RPC
connection is up. This could in theory interact badly with a
remote peer that stops reading and processing messages from the
receive queue when there is a backlog in the send queue for a
given connection (ovsdb-server is an example of a program that
behaves this way). This commit fixes the problem by expanding
the definition of "activity" to include successfully sending
JSON-RPC data that was previously queued.
The above change is exactly analogous to the similar change
made to the rconn library in commit 133f2dc95454 (rconn: Treat
draining a message from the send queue as activity.).
Bug #12789.
Signed-off-by: Ben Pfaff <b...@nicira.com>
---
lib/jsonrpc.c | 13 +++++++++++++
python/ovs/jsonrpc.py | 11 ++++++++++-
2 files changed, 23 insertions(+), 1 deletions(-)
diff --git a/lib/jsonrpc.c b/lib/jsonrpc.c
index c4d7dd2..9c0aaa9 100644
--- a/lib/jsonrpc.c
+++ b/lib/jsonrpc.c
@@ -880,9 +880,22 @@ jsonrpc_session_run(struct jsonrpc_session *s)
}
if (s->rpc) {
+ size_t backlog;
int error;
+ backlog = jsonrpc_get_backlog(s->rpc);
jsonrpc_run(s->rpc);
+ if (jsonrpc_get_backlog(s->rpc) < backlog) {
+ /* Data previously caught in a queue was successfully sent.
+ *
+ * We don't count data that is successfully sent immediately as
+ * activity, because there's a lot of queuing downstream from us,
+ * which means that we can push a lot of data into a connection
+ * that has stalled and won't ever recover.
+ */
+ reconnect_activity(s->reconnect, time_msec());
+ }
+
error = jsonrpc_get_status(s->rpc);
if (error) {
reconnect_disconnected(s->reconnect, time_msec(), error);
diff --git a/python/ovs/jsonrpc.py b/python/ovs/jsonrpc.py
index cb471cb..4496bba 100644
--- a/python/ovs/jsonrpc.py
+++ b/python/ovs/jsonrpc.py
@@ -502,9 +502,18 @@ class Session(object):
def recv(self):
if self.rpc is not None:
+ backlog = self.rpc.get_backlog()
error, msg = self.rpc.recv()
- if not error:
+ if self.rpc.get_backlog() < backlog:
+ # Data previously caught in a queue was successfully sent.
+ #
+ # We don't count data that is successfully sent immediately as
+ # activity, because there's a lot of queuing downstream from
+ # us, which means that we can push a lot of data into a
+ # connection that has stalled and won't ever recover.
self.reconnect.activity(ovs.timeval.msec())
+
+ if not error:
if msg.type == Message.T_REQUEST and msg.method == "echo":
# Echo request. Send reply.
self.send(Message.create_reply(msg.params, msg.id))
--
1.7.2.5
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