> On Aug 16, 2017, at 12:19 PM, Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote:
>
> Sometimes, we only want to know that the RPC message is in the process
> of being transmitted. Add a function to allow that.
The last time I tried these last two, they resulted in a significant
performance regression. Is there anything I can do to help track
that down?
> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
> ---
> include/linux/sunrpc/sched.h | 3 +++
> net/sunrpc/sched.c | 22 ++++++++++++++++++++++
> net/sunrpc/xprt.c | 6 ++++++
> 3 files changed, 31 insertions(+)
>
> diff --git a/include/linux/sunrpc/sched.h b/include/linux/sunrpc/sched.h
> index c1768f9d993b..148cd6c5d2eb 100644
> --- a/include/linux/sunrpc/sched.h
> +++ b/include/linux/sunrpc/sched.h
> @@ -141,6 +141,8 @@ struct rpc_task_setup {
> #define RPC_TASK_ACTIVE 2
> #define RPC_TASK_MSG_RECV 3
> #define RPC_TASK_MSG_RECV_WAIT 4
> +#define RPC_TASK_MSG_XMIT 5
> +#define RPC_TASK_MSG_XMIT_WAIT 6
>
> #define RPC_IS_RUNNING(t) test_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
> #define rpc_set_running(t) set_bit(RPC_TASK_RUNNING, &(t)->tk_runstate)
> @@ -246,6 +248,7 @@ void rpc_free(struct rpc_task *);
> int rpciod_up(void);
> void rpciod_down(void);
> int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *);
> +int rpc_wait_for_msg_send(struct rpc_task *task);
> #if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
> struct net;
> void rpc_show_tasks(struct net *);
> diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
> index 0cc83839c13c..30509a4d7e00 100644
> --- a/net/sunrpc/sched.c
> +++ b/net/sunrpc/sched.c
> @@ -320,6 +320,19 @@ int __rpc_wait_for_completion_task(struct rpc_task *task, wait_bit_action_f *act
> EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task);
>
> /*
> + * Allow callers to wait for completion of an RPC call
> + */
> +int rpc_wait_for_msg_send(struct rpc_task *task)
> +{
> + if (!test_bit(RPC_TASK_MSG_XMIT, &task->tk_runstate))
> + return 0;
> + set_bit(RPC_TASK_MSG_XMIT_WAIT, &task->tk_runstate);
> + return wait_on_bit_action(&task->tk_runstate, RPC_TASK_MSG_XMIT,
> + rpc_wait_bit_killable, TASK_KILLABLE);
> +}
> +EXPORT_SYMBOL_GPL(rpc_wait_for_msg_send);
> +
> +/*
> * Make an RPC task runnable.
> *
> * Note: If the task is ASYNC, and is being made runnable after sitting on an
> @@ -700,6 +713,7 @@ rpc_reset_task_statistics(struct rpc_task *task)
> {
> task->tk_timeouts = 0;
> task->tk_flags &= ~(RPC_CALL_MAJORSEEN|RPC_TASK_KILLED|RPC_TASK_SENT);
> + set_bit(RPC_TASK_MSG_XMIT, &task->tk_runstate);
>
> rpc_init_task_statistics(task);
> }
> @@ -928,6 +942,7 @@ static void rpc_init_task(struct rpc_task *task, const struct rpc_task_setup *ta
> memset(task, 0, sizeof(*task));
> atomic_set(&task->tk_count, 1);
> task->tk_flags = task_setup_data->flags;
> + task->tk_runstate = BIT(RPC_TASK_MSG_XMIT);
> task->tk_ops = task_setup_data->callback_ops;
> task->tk_calldata = task_setup_data->callback_data;
> INIT_LIST_HEAD(&task->tk_task);
> @@ -1012,6 +1027,13 @@ static void rpc_async_release(struct work_struct *work)
>
> static void rpc_release_resources_task(struct rpc_task *task)
> {
> + if (test_bit(RPC_TASK_MSG_XMIT, &task->tk_runstate)) {
> + clear_bit(RPC_TASK_MSG_XMIT, &task->tk_runstate);
> + smp_mb__after_atomic();
> + if (test_bit(RPC_TASK_MSG_XMIT_WAIT, &task->tk_runstate))
> + wake_up_bit(&task->tk_runstate, RPC_TASK_MSG_XMIT);
> + }
> +
> xprt_release(task);
> if (task->tk_msg.rpc_cred) {
> put_rpccred(task->tk_msg.rpc_cred);
> diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
> index a558e8c620c0..62c379865f7c 100644
> --- a/net/sunrpc/xprt.c
> +++ b/net/sunrpc/xprt.c
> @@ -978,6 +978,12 @@ bool xprt_prepare_transmit(struct rpc_task *task)
> goto out_unlock;
> }
> ret = true;
> + if (test_bit(RPC_TASK_MSG_XMIT, &task->tk_runstate)) {
> + clear_bit(RPC_TASK_MSG_XMIT, &task->tk_runstate);
> + smp_mb__after_atomic();
> + if (test_bit(RPC_TASK_MSG_XMIT_WAIT, &task->tk_runstate))
> + wake_up_bit(&task->tk_runstate, RPC_TASK_MSG_XMIT);
> + }
> out_unlock:
> spin_unlock_bh(&xprt->transport_lock);
> return ret;
> --
> 2.13.5
>
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--
Chuck Lever
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