diff options
| author | Tony Lu <tonylu@linux.alibaba.com> | 2022-01-30 21:02:55 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2022-01-31 18:08:20 +0300 |
| commit | ea785a1a573b390a150010b3c5b81e1ccd8c98a8 (patch) | |
| tree | 08b9e9691157c96edd94279a6625591a27bcd05d /net/smc | |
| parent | 01b2a995156d11166da00ce254d59bd7f7cefb92 (diff) | |
| download | linux-ea785a1a573b390a150010b3c5b81e1ccd8c98a8.tar.xz | |
net/smc: Send directly when TCP_CORK is cleared
According to the man page of TCP_CORK [1], if set, don't send out
partial frames. All queued partial frames are sent when option is
cleared again.
When applications call setsockopt to disable TCP_CORK, this call is
protected by lock_sock(), and tries to mod_delayed_work() to 0, in order
to send pending data right now. However, the delayed work smc_tx_work is
also protected by lock_sock(). There introduces lock contention for
sending data.
To fix it, send pending data directly which acts like TCP, without
lock_sock() protected in the context of setsockopt (already lock_sock()ed),
and cancel unnecessary dealyed work, which is protected by lock.
[1] https://linux.die.net/man/7/tcp
Signed-off-by: Tony Lu <tonylu@linux.alibaba.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/smc')
| -rw-r--r-- | net/smc/af_smc.c | 4 | ||||
| -rw-r--r-- | net/smc/smc_tx.c | 25 | ||||
| -rw-r--r-- | net/smc/smc_tx.h | 1 |
3 files changed, 18 insertions, 12 deletions
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index d5ea62b82bb8..3137d8e5956d 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -2523,8 +2523,8 @@ static int smc_setsockopt(struct socket *sock, int level, int optname, sk->sk_state != SMC_CLOSED) { if (!val) { SMC_STAT_INC(smc, cork_cnt); - mod_delayed_work(smc->conn.lgr->tx_wq, - &smc->conn.tx_work, 0); + smc_tx_pending(&smc->conn); + cancel_delayed_work(&smc->conn.tx_work); } } break; diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index be241d53020f..7b0b6e24582f 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -597,27 +597,32 @@ int smc_tx_sndbuf_nonempty(struct smc_connection *conn) return rc; } -/* Wakeup sndbuf consumers from process context - * since there is more data to transmit - */ -void smc_tx_work(struct work_struct *work) +void smc_tx_pending(struct smc_connection *conn) { - struct smc_connection *conn = container_of(to_delayed_work(work), - struct smc_connection, - tx_work); struct smc_sock *smc = container_of(conn, struct smc_sock, conn); int rc; - lock_sock(&smc->sk); if (smc->sk.sk_err) - goto out; + return; rc = smc_tx_sndbuf_nonempty(conn); if (!rc && conn->local_rx_ctrl.prod_flags.write_blocked && !atomic_read(&conn->bytes_to_rcv)) conn->local_rx_ctrl.prod_flags.write_blocked = 0; +} + +/* Wakeup sndbuf consumers from process context + * since there is more data to transmit + */ +void smc_tx_work(struct work_struct *work) +{ + struct smc_connection *conn = container_of(to_delayed_work(work), + struct smc_connection, + tx_work); + struct smc_sock *smc = container_of(conn, struct smc_sock, conn); -out: + lock_sock(&smc->sk); + smc_tx_pending(conn); release_sock(&smc->sk); } diff --git a/net/smc/smc_tx.h b/net/smc/smc_tx.h index 07e6ad76224a..a59f370b8b43 100644 --- a/net/smc/smc_tx.h +++ b/net/smc/smc_tx.h @@ -27,6 +27,7 @@ static inline int smc_tx_prepared_sends(struct smc_connection *conn) return smc_curs_diff(conn->sndbuf_desc->len, &sent, &prep); } +void smc_tx_pending(struct smc_connection *conn); void smc_tx_work(struct work_struct *work); void smc_tx_init(struct smc_sock *smc); int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len); |