[PATCH] RPC: separate TCP and UDP write space callbacks
Split the socket write space callback function into a TCP version and UDP
version, eliminating one dependence on the "xprt->stream" variable.
Keep the common pieces of this path in xprt.c so other transports can use
it too.
Test-plan:
Write-intensive workload on a single mount point.
Version: Thu, 11 Aug 2005 16:07:51 -0400
Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h
index bfbc492..e73174c 100644
--- a/include/linux/sunrpc/xprt.h
+++ b/include/linux/sunrpc/xprt.h
@@ -240,6 +240,8 @@
* Transport switch helper functions
*/
void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
+void xprt_wait_for_buffer_space(struct rpc_task *task);
+void xprt_write_space(struct rpc_xprt *xprt);
struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid);
void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied);
void xprt_disconnect(struct rpc_xprt *xprt);
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index 247fa1e..31ef7dc 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -241,6 +241,40 @@
rpc_wake_up(&xprt->pending);
}
+/**
+ * xprt_wait_for_buffer_space - wait for transport output buffer to clear
+ * @task: task to be put to sleep
+ *
+ */
+void xprt_wait_for_buffer_space(struct rpc_task *task)
+{
+ struct rpc_rqst *req = task->tk_rqstp;
+ struct rpc_xprt *xprt = req->rq_xprt;
+
+ task->tk_timeout = req->rq_timeout;
+ rpc_sleep_on(&xprt->pending, task, NULL, NULL);
+}
+
+/**
+ * xprt_write_space - wake the task waiting for transport output buffer space
+ * @xprt: transport with waiting tasks
+ *
+ * Can be called in a soft IRQ context, so xprt_write_space never sleeps.
+ */
+void xprt_write_space(struct rpc_xprt *xprt)
+{
+ if (unlikely(xprt->shutdown))
+ return;
+
+ spin_lock_bh(&xprt->transport_lock);
+ if (xprt->snd_task) {
+ dprintk("RPC: write space: waking waiting task on xprt %p\n",
+ xprt);
+ rpc_wake_up_task(xprt->snd_task);
+ }
+ spin_unlock_bh(&xprt->transport_lock);
+}
+
static void xprt_reset_majortimeo(struct rpc_rqst *req)
{
struct rpc_timeout *to = &req->rq_xprt->timeout;
diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 7f0b9f7..70a772d 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -308,15 +308,13 @@
if (status == -EAGAIN) {
if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {
- /* Protect against races with xs_write_space */
+ /* Protect against races with write_space */
spin_lock_bh(&xprt->transport_lock);
/* Don't race with disconnect */
if (!xprt_connected(xprt))
task->tk_status = -ENOTCONN;
- else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags)) {
- task->tk_timeout = req->rq_timeout;
- rpc_sleep_on(&xprt->pending, task, NULL, NULL);
- }
+ else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags))
+ xprt_wait_for_buffer_space(task);
spin_unlock_bh(&xprt->transport_lock);
return status;
}
@@ -721,45 +719,68 @@
}
/**
- * xs_write_space - callback invoked when socket buffer space becomes
- * available
+ * xs_udp_write_space - callback invoked when socket buffer space
+ * becomes available
* @sk: socket whose state has changed
*
* Called when more output buffer space is available for this socket.
* We try not to wake our writers until they can make "significant"
- * progress, otherwise we'll waste resources thrashing sock_sendmsg
+ * progress, otherwise we'll waste resources thrashing kernel_sendmsg
* with a bunch of small requests.
*/
-static void xs_write_space(struct sock *sk)
+static void xs_udp_write_space(struct sock *sk)
{
- struct rpc_xprt *xprt;
- struct socket *sock;
-
read_lock(&sk->sk_callback_lock);
- if (!(xprt = xprt_from_sock(sk)) || !(sock = sk->sk_socket))
- goto out;
- if (xprt->shutdown)
- goto out;
- /* Wait until we have enough socket memory */
- if (xprt->stream) {
- /* from net/core/stream.c:sk_stream_write_space */
- if (sk_stream_wspace(sk) < sk_stream_min_wspace(sk))
+ /* from net/core/sock.c:sock_def_write_space */
+ if (sock_writeable(sk)) {
+ struct socket *sock;
+ struct rpc_xprt *xprt;
+
+ if (unlikely(!(sock = sk->sk_socket)))
goto out;
- } else {
- /* from net/core/sock.c:sock_def_write_space */
- if (!sock_writeable(sk))
+ if (unlikely(!(xprt = xprt_from_sock(sk))))
goto out;
+ if (unlikely(!test_and_clear_bit(SOCK_NOSPACE, &sock->flags)))
+ goto out;
+
+ xprt_write_space(xprt);
}
- if (!test_and_clear_bit(SOCK_NOSPACE, &sock->flags))
- goto out;
+ out:
+ read_unlock(&sk->sk_callback_lock);
+}
- spin_lock_bh(&xprt->transport_lock);
- if (xprt->snd_task)
- rpc_wake_up_task(xprt->snd_task);
- spin_unlock_bh(&xprt->transport_lock);
-out:
+/**
+ * xs_tcp_write_space - callback invoked when socket buffer space
+ * becomes available
+ * @sk: socket whose state has changed
+ *
+ * Called when more output buffer space is available for this socket.
+ * We try not to wake our writers until they can make "significant"
+ * progress, otherwise we'll waste resources thrashing kernel_sendmsg
+ * with a bunch of small requests.
+ */
+static void xs_tcp_write_space(struct sock *sk)
+{
+ read_lock(&sk->sk_callback_lock);
+
+ /* from net/core/stream.c:sk_stream_write_space */
+ if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
+ struct socket *sock;
+ struct rpc_xprt *xprt;
+
+ if (unlikely(!(sock = sk->sk_socket)))
+ goto out;
+ if (unlikely(!(xprt = xprt_from_sock(sk))))
+ goto out;
+ if (unlikely(!test_and_clear_bit(SOCK_NOSPACE, &sock->flags)))
+ goto out;
+
+ xprt_write_space(xprt);
+ }
+
+ out:
read_unlock(&sk->sk_callback_lock);
}
@@ -855,15 +876,16 @@
xprt->old_write_space = sk->sk_write_space;
if (xprt->prot == IPPROTO_UDP) {
sk->sk_data_ready = xs_udp_data_ready;
+ sk->sk_write_space = xs_udp_write_space;
sk->sk_no_check = UDP_CSUM_NORCV;
xprt_set_connected(xprt);
} else {
tcp_sk(sk)->nonagle = 1; /* disable Nagle's algorithm */
sk->sk_data_ready = xs_tcp_data_ready;
sk->sk_state_change = xs_tcp_state_change;
+ sk->sk_write_space = xs_tcp_write_space;
xprt_clear_connected(xprt);
}
- sk->sk_write_space = xs_write_space;
/* Reset to new socket */
xprt->sock = sock;
