SUNRPC: Use TCP_CORK to optimise send performance on the server

Use a counter to keep track of how many requests are queued behind the
xprt->xpt_mutex, and keep TCP_CORK set until the queue is empty.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Link: https://lore.kernel.org/linux-nfs/20210213202532.23146-1-trondmy@kernel.org/T/#u
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Trond Myklebust 2021-02-16 12:17:22 -05:00 committed by Chuck Lever
parent 0ac24c320c
commit e0a912e8dd
2 changed files with 9 additions and 1 deletions

View File

@ -35,6 +35,8 @@ struct svc_sock {
/* Total length of the data (not including fragment headers)
* received so far in the fragments making up this rpc: */
u32 sk_datalen;
/* Number of queued send requests */
atomic_t sk_sendqlen;
struct page * sk_pages[RPCSVC_MAXPAGES]; /* received data */
};

View File

@ -1171,18 +1171,23 @@ static int svc_tcp_sendto(struct svc_rqst *rqstp)
svc_tcp_release_rqst(rqstp);
atomic_inc(&svsk->sk_sendqlen);
mutex_lock(&xprt->xpt_mutex);
if (svc_xprt_is_dead(xprt))
goto out_notconn;
tcp_sock_set_cork(svsk->sk_sk, true);
err = svc_tcp_sendmsg(svsk->sk_sock, &msg, xdr, marker, &sent);
xdr_free_bvec(xdr);
trace_svcsock_tcp_send(xprt, err < 0 ? err : sent);
if (err < 0 || sent != (xdr->len + sizeof(marker)))
goto out_close;
if (atomic_dec_and_test(&svsk->sk_sendqlen))
tcp_sock_set_cork(svsk->sk_sk, false);
mutex_unlock(&xprt->xpt_mutex);
return sent;
out_notconn:
atomic_dec(&svsk->sk_sendqlen);
mutex_unlock(&xprt->xpt_mutex);
return -ENOTCONN;
out_close:
@ -1192,6 +1197,7 @@ static int svc_tcp_sendto(struct svc_rqst *rqstp)
(err < 0) ? err : sent, xdr->len);
set_bit(XPT_CLOSE, &xprt->xpt_flags);
svc_xprt_enqueue(xprt);
atomic_dec(&svsk->sk_sendqlen);
mutex_unlock(&xprt->xpt_mutex);
return -EAGAIN;
}
@ -1261,7 +1267,7 @@ static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
svsk->sk_datalen = 0;
memset(&svsk->sk_pages[0], 0, sizeof(svsk->sk_pages));
tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
tcp_sock_set_nodelay(sk);
set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
switch (sk->sk_state) {