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SUNRPC: Fix the TCP server's send buffer accounting

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Currently, the sunrpc server is refusing to allow us to process new RPC
calls if the TCP send buffer is 2/3 full, even if we do actually have
enough free space to guarantee that we can send another request.
The following patch fixes svc_tcp_has_wspace() so that we only stop
processing requests if we know that the socket buffer cannot possibly fit
another reply.

It also fixes the tcp write_space() callback so that we only clear the
SOCK_NOSPACE flag when the TCP send buffer is less than 2/3 full.
This should ensure that the send window will grow as per the standard TCP
socket code.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
This commit is contained in:
Trond Myklebust 2009-05-18 17:47:56 -04:00 committed by J. Bruce Fields
parent ab52ae6db0
commit 47fcb03fef
1 changed files with 18 additions and 17 deletions
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33
net/sunrpc/svcsock.c
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@ -380,6 +380,7 @@ static void svc_sock_setbufsize(struct socket *sock, unsigned int snd,
sock->sk->sk_sndbuf = snd * 2;
sock->sk->sk_rcvbuf = rcv * 2;
sock->sk->sk_userlocks |= SOCK_SNDBUF_LOCK|SOCK_RCVBUF_LOCK;
sock->sk->sk_write_space(sock->sk);
release_sock(sock->sk);
#endif
}
@ -421,6 +422,15 @@ static void svc_write_space(struct sock *sk)
}
}
static void svc_tcp_write_space(struct sock *sk)
{
struct socket *sock = sk->sk_socket;
if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) && sock)
clear_bit(SOCK_NOSPACE, &sock->flags);
svc_write_space(sk);
}
/*
* Copy the UDP datagram's destination address to the rqstp structure.
* The 'destination' address in this case is the address to which the
@ -1017,23 +1027,14 @@ static int svc_tcp_has_wspace(struct svc_xprt *xprt)
struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
struct svc_serv *serv = svsk->sk_xprt.xpt_server;
int required;
int wspace;
/*
* Set the SOCK_NOSPACE flag before checking the available
* sock space.
*/
set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
required = atomic_read(&svsk->sk_xprt.xpt_reserved) + serv->sv_max_mesg;
wspace = sk_stream_wspace(svsk->sk_sk);
if (wspace < sk_stream_min_wspace(svsk->sk_sk))
return 0;
if (required * 2 > wspace)
return 0;
clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
if (test_bit(XPT_LISTENER, &xprt->xpt_flags))
return 1;
required = atomic_read(&xprt->xpt_reserved) + serv->sv_max_mesg;
if (sk_stream_wspace(svsk->sk_sk) >= required)
return 1;
set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
return 0;
}
static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
@ -1089,7 +1090,7 @@ static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
dprintk("setting up TCP socket for reading\n");
sk->sk_state_change = svc_tcp_state_change;
sk->sk_data_ready = svc_tcp_data_ready;
sk->sk_write_space = svc_write_space;
sk->sk_write_space = svc_tcp_write_space;
svsk->sk_reclen = 0;
svsk->sk_tcplen = 0;