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[PATCH] RPC: separate TCP and UDP write space callbacks

Browse source 
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>
This commit is contained in:
Chuck Lever 2005-08-11 16:25:50 -04:00 committed by Trond Myklebust
parent 55aa4f58aa
commit c7b2cae8a6
3 changed files with 89 additions and 31 deletions
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2
include/linux/sunrpc/xprt.h
View file

@ -240,6 +240,8 @@ int xprt_destroy(struct rpc_xprt *xprt);
* 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);

34
net/sunrpc/xprt.c
View file

@ -241,6 +241,40 @@ void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status)
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;

84
net/sunrpc/xprtsock.c
View file

@ -308,15 +308,13 @@ static int xs_send_request(struct rpc_task *task)
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 @@ static void xs_tcp_state_change(struct sock *sk)
}
/**
* 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 @@ static void xs_bind(struct rpc_xprt *xprt, struct socket *sock)
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;