Re: [PATCH 6/6] RPC: adjust timeout for connect, bind, restablish so that they sensitive to the major time out value

[Chuck Lever <chuck.lever@oracle.com>]

Hi Alexandros-

I think we need a little more than the short description for these 
patches.  Can you explain why the extra logic in xs_connect is 
necessary?  What exactly happens if the RENEW doesn't reach the server 
because the transport can't be reconnected?

In other words, what problem are you trying to address here?

On 02/02/2010 07:06 PM, Alexandros Batsakis wrote:
> Signed-off-by: Alexandros Batsakis<batsakis@netapp.com>
> ---
>   net/sunrpc/clnt.c     |    2 +-
>   net/sunrpc/sunrpc.h   |    2 ++
>   net/sunrpc/xprt.c     |   18 +++++++++++++++---
>   net/sunrpc/xprtsock.c |   12 ++++++++++--
>   4 files changed, 28 insertions(+), 6 deletions(-)
>
> diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c
> index 154034b..8e552cd 100644
> --- a/net/sunrpc/clnt.c
> +++ b/net/sunrpc/clnt.c
> @@ -1019,7 +1019,7 @@ call_bind(struct rpc_task *task)
>   	task->tk_action = call_connect;
>   	if (!xprt_bound(xprt)) {
>   		task->tk_action = call_bind_status;
> -		task->tk_timeout = xprt->bind_timeout;
> +		xprt_set_timeout_sane(task, xprt->bind_timeout);
>   		xprt->ops->rpcbind(task);
>   	}
>   }
> diff --git a/net/sunrpc/sunrpc.h b/net/sunrpc/sunrpc.h
> index 90c292e..87c7aaa 100644
> --- a/net/sunrpc/sunrpc.h
> +++ b/net/sunrpc/sunrpc.h
> @@ -37,6 +37,8 @@ struct rpc_buffer {
>   	char	data[];
>   };
>
> +void xprt_set_timeout_sane(struct rpc_task *task, unsigned long timeout);
> +
>   static inline int rpc_reply_expected(struct rpc_task *task)
>   {
>   	return (task->tk_msg.rpc_proc != NULL)&&
> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
> index 469de29..f6f3988 100644
> --- a/net/sunrpc/xprt.c
> +++ b/net/sunrpc/xprt.c
> @@ -482,7 +482,7 @@ void xprt_wait_for_buffer_space(struct rpc_task *task, rpc_action action)
>   	struct rpc_rqst *req = task->tk_rqstp;
>   	struct rpc_xprt *xprt = req->rq_xprt;
>
> -	task->tk_timeout = req->rq_timeout;
> +	xprt_set_timeout_sane(task, req->rq_timeout);
>   	rpc_sleep_on(&xprt->pending, task, action);
>   }
>   EXPORT_SYMBOL_GPL(xprt_wait_for_buffer_space);
> @@ -518,7 +518,7 @@ EXPORT_SYMBOL_GPL(xprt_write_space);
>    */
>   void xprt_set_retrans_timeout_def(struct rpc_task *task)
>   {
> -	task->tk_timeout = task->tk_rqstp->rq_timeout;
> +	xprt_set_timeout_sane(task, task->tk_rqstp->rq_timeout);
>   }
>   EXPORT_SYMBOL_GPL(xprt_set_retrans_timeout_def);
>
> @@ -682,6 +682,18 @@ out_abort:
>   	spin_unlock(&xprt->transport_lock);
>   }
>
> +void xprt_set_timeout_sane(struct rpc_task *task, unsigned long timeout)

xprt_set_timeout_sane?  That's amusing, but it isn't very descriptive to 
someone who doesn't know why this extra function is needed.

> +{
> +	unsigned long majorto = task->tk_rqstp->rq_majortimeo;
> +
> +	if (majorto<= jiffies)
> +		task->tk_timeout = 5 * HZ;
> +	else if (timeout>  majorto - jiffies)
> +		task->tk_timeout = 2 * (majorto - jiffies) / 3;
> +	else
> +		task->tk_timeout = timeout;
> +}
> +
>   /**
>    * xprt_connect - schedule a transport connect operation
>    * @task: RPC task that is requesting the connect
> @@ -710,7 +722,7 @@ void xprt_connect(struct rpc_task *task)
>   		if (task->tk_rqstp)
>   			task->tk_rqstp->rq_bytes_sent = 0;
>
> -		task->tk_timeout = xprt->connect_timeout;
> +		xprt_set_timeout_sane(task, xprt->connect_timeout);
>   		rpc_sleep_on(&xprt->pending, task, xprt_connect_status);
>   		xprt->stat.connect_start = jiffies;
>   		xprt->ops->connect(task);
> diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
> index 721bafd..7fcc97f 100644
> --- a/net/sunrpc/xprtsock.c
> +++ b/net/sunrpc/xprtsock.c
> @@ -2020,9 +2020,17 @@ static void xs_connect(struct rpc_task *task)
>   		return;
>
>   	if (transport->sock != NULL&&  !RPC_IS_SOFTCONN(task)) {
> +		unsigned long majorto = task->tk_rqstp->rq_majortimeo;
> +
> +		if (majorto<= jiffies)
> +			xprt->reestablish_timeout = 5 * HZ;
> +		else if (xprt->reestablish_timeout>  majorto - jiffies)
> +			xprt->reestablish_timeout = 2 * (majorto - jiffies)
> +			  / 3;

This looks like the code you added above in _sane.  Can you reuse that 
code here?

> +
>   		dprintk("RPC:       xs_connect delayed xprt %p for %lu "
> -				"seconds\n",
> -				xprt, xprt->reestablish_timeout / HZ);
> +			"seconds\n",
> +			xprt, xprt->reestablish_timeout + (HZ - 1) / HZ);
>   		queue_delayed_work(rpciod_workqueue,
>   				&transport->connect_worker,
>   				   xprt->reestablish_timeout);


-- 
chuck[dot]lever[at]oracle[dot]com