2023-08-20 00:34:14

by Trond Myklebust

Subject: [PATCH v2 1/5] SUNRPC: Set the TCP_SYNCNT to match the socket timeout

From: Trond Myklebust <[email protected]>

Set the TCP SYN count so that we abort the connection attempt at around
the expected timeout value.

Signed-off-by: Trond Myklebust <[email protected]>
---
net/sunrpc/xprtsock.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 9f010369100a..47d0b6a8c32e 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2230,9 +2230,13 @@ static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
struct socket *sock)
{
struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+ struct net *net = sock_net(sock->sk);
+ unsigned long connect_timeout;
+ unsigned long syn_retries;
unsigned int keepidle;
unsigned int keepcnt;
unsigned int timeo;
+ unsigned long t;

spin_lock(&xprt->transport_lock);
keepidle = DIV_ROUND_UP(xprt->timeout->to_initval, HZ);
@@ -2250,6 +2254,16 @@ static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,

/* TCP user timeout (see RFC5482) */
tcp_sock_set_user_timeout(sock->sk, timeo);
+
+ /* Connect timeout */
+ connect_timeout = max_t(unsigned long,
+ DIV_ROUND_UP(xprt->connect_timeout, HZ), 1);
+ syn_retries = max_t(unsigned long,
+ READ_ONCE(net->ipv4.sysctl_tcp_syn_retries), 1);
+ for (t = 0; t <= syn_retries && (1UL << t) < connect_timeout; t++)
+ ;
+ if (t <= syn_retries)
+ tcp_sock_set_syncnt(sock->sk, t - 1);
}

static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
--
2.41.0

2023-08-20 01:00:15

by Trond Myklebust

Subject: [PATCH v2 2/5] SUNRPC: Refactor and simplify connect timeout

From: Trond Myklebust <[email protected]>

Instead of requiring the requests to redrive the connection several
times, just let the TCP connect code manage it now that we've adjusted
the TCP_SYNCNT value.

Signed-off-by: Trond Myklebust <[email protected]>
---
net/sunrpc/xprtsock.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)

diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c
index 47d0b6a8c32e..e558f0024fe5 100644
--- a/net/sunrpc/xprtsock.c
+++ b/net/sunrpc/xprtsock.c
@@ -2266,6 +2266,25 @@ static void xs_tcp_set_socket_timeouts(struct rpc_xprt *xprt,
tcp_sock_set_syncnt(sock->sk, t - 1);
}

+static void xs_tcp_do_set_connect_timeout(struct rpc_xprt *xprt,
+ unsigned long connect_timeout)
+{
+ struct sock_xprt *transport =
+ container_of(xprt, struct sock_xprt, xprt);
+ struct rpc_timeout to;
+ unsigned long initval;
+
+ memcpy(&to, xprt->timeout, sizeof(to));
+ /* Arbitrary lower limit */
+ initval = max_t(unsigned long, connect_timeout, XS_TCP_INIT_REEST_TO);
+ to.to_initval = initval;
+ to.to_maxval = initval;
+ to.to_retries = 0;
+ memcpy(&transport->tcp_timeout, &to, sizeof(transport->tcp_timeout));
+ xprt->timeout = &transport->tcp_timeout;
+ xprt->connect_timeout = connect_timeout;
+}
+
static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
unsigned long connect_timeout,
unsigned long reconnect_timeout)
@@ -2277,19 +2296,8 @@ static void xs_tcp_set_connect_timeout(struct rpc_xprt *xprt,
spin_lock(&xprt->transport_lock);
if (reconnect_timeout < xprt->max_reconnect_timeout)
xprt->max_reconnect_timeout = reconnect_timeout;
- if (connect_timeout < xprt->connect_timeout) {
- memcpy(&to, xprt->timeout, sizeof(to));
- initval = DIV_ROUND_UP(connect_timeout, to.to_retries + 1);
- /* Arbitrary lower limit */
- if (initval < XS_TCP_INIT_REEST_TO << 1)
- initval = XS_TCP_INIT_REEST_TO << 1;
- to.to_initval = initval;
- to.to_maxval = initval;
- memcpy(&transport->tcp_timeout, &to,
- sizeof(transport->tcp_timeout));
- xprt->timeout = &transport->tcp_timeout;
- xprt->connect_timeout = connect_timeout;
- }
+ if (connect_timeout < xprt->connect_timeout)
+ xs_tcp_do_set_connect_timeout(xprt, connect_timeout);
set_bit(XPRT_SOCK_UPD_TIMEOUT, &transport->sock_state);
spin_unlock(&xprt->transport_lock);
}
--
2.41.0