2016-08-04 13:01:49

by Trond Myklebust

Subject: [PATCH 1/2] SUNRPC: Fix reconnection timeouts

When the connect attempt fails and backs off, we should start the clock
at the last connection attempt, not time at which we queue up the
reconnect job.

Signed-off-by: Trond Myklebust <[email protected]>
---
net/sunrpc/xprtsock.c | 27 ++++++++++++++++++++-------
1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index c6b1d48c4319..5eebf48cffa0 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2173,6 +2173,8 @@ static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
write_unlock_bh(&sk->sk_callback_lock);
}
xs_udp_do_set_buffer_size(xprt);
+
+ xprt->stat.connect_start = jiffies;
}

static void xs_udp_setup_socket(struct work_struct *work)
@@ -2373,6 +2375,16 @@ out:
xprt_wake_pending_tasks(xprt, status);
}

+static unsigned long xs_reconnect_delay(const struct rpc_xprt *xprt)
+{
+ unsigned long start, now = jiffies;
+
+ start = xprt->stat.connect_start + xprt->reestablish_timeout;
+ if (time_after(start, now))
+ return start - now;
+ return 0;
+}
+
/**
* xs_connect - connect a socket to a remote endpoint
* @xprt: pointer to transport structure
@@ -2390,6 +2402,7 @@ out:
static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
{
struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+ unsigned long delay = 0;

WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));

@@ -2401,19 +2414,19 @@ static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
/* Start by resetting any existing state */
xs_reset_transport(transport);

- queue_delayed_work(xprtiod_workqueue,
- &transport->connect_worker,
- xprt->reestablish_timeout);
+ delay = xs_reconnect_delay(xprt);
+
xprt->reestablish_timeout <<= 1;
if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
- } else {
+ } else
dprintk("RPC: xs_connect scheduled xprt %p\n", xprt);
- queue_delayed_work(xprtiod_workqueue,
- &transport->connect_worker, 0);
- }
+
+ queue_delayed_work(xprtiod_workqueue,
+ &transport->connect_worker,
+ delay);
}

/**
--
2.7.4

2016-08-04 13:01:50

by Trond Myklebust

Subject: [PATCH 2/2] SUNRPC: Limit the reconnect backoff timer to the max RPC message timeout

Signed-off-by: Trond Myklebust <[email protected]>
---
net/sunrpc/xprtsock.c | 17 ++++++++++++-----
1 file changed, 12 insertions(+), 5 deletions(-)

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 5eebf48cffa0..b828695cc647 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2385,6 +2385,17 @@ static unsigned long xs_reconnect_delay(const struct rpc_xprt *xprt)
return 0;
}

+static void xs_reconnect_backoff(struct rpc_xprt *xprt)
+{
+ xprt->reestablish_timeout <<= 1;
+ if (xprt->reestablish_timeout > xprt->timeout->to_maxval)
+ xprt->reestablish_timeout = xprt->timeout->to_maxval;
+ if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
+ xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
+ if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
+ xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
+}
+
/**
* xs_connect - connect a socket to a remote endpoint
* @xprt: pointer to transport structure
@@ -2415,12 +2426,8 @@ static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
xs_reset_transport(transport);

delay = xs_reconnect_delay(xprt);
+ xs_reconnect_backoff(xprt);

- xprt->reestablish_timeout <<= 1;
- if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
- xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
- if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
- xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
} else
dprintk("RPC: xs_connect scheduled xprt %p\n", xprt);

--
2.7.4