diff options
Diffstat (limited to 'net/smc/smc_tx.c')
| -rw-r--r-- | net/smc/smc_tx.c | 154 |
1 files changed, 130 insertions, 24 deletions
diff --git a/net/smc/smc_tx.c b/net/smc/smc_tx.c index be241d53020f..98ca9229fe87 100644 --- a/net/smc/smc_tx.c +++ b/net/smc/smc_tx.c @@ -31,7 +31,6 @@ #include "smc_tracepoint.h" #define SMC_TX_WORK_DELAY 0 -#define SMC_TX_CORK_DELAY (HZ >> 2) /* 250 ms */ /***************************** sndbuf producer *******************************/ @@ -132,6 +131,51 @@ static bool smc_tx_is_corked(struct smc_sock *smc) return (tp->nonagle & TCP_NAGLE_CORK) ? true : false; } +/* If we have pending CDC messages, do not send: + * Because CQE of this CDC message will happen shortly, it gives + * a chance to coalesce future sendmsg() payload in to one RDMA Write, + * without need for a timer, and with no latency trade off. + * Algorithm here: + * 1. First message should never cork + * 2. If we have pending Tx CDC messages, wait for the first CDC + * message's completion + * 3. Don't cork to much data in a single RDMA Write to prevent burst + * traffic, total corked message should not exceed sendbuf/2 + */ +static bool smc_should_autocork(struct smc_sock *smc) +{ + struct smc_connection *conn = &smc->conn; + int corking_size; + + corking_size = min_t(unsigned int, conn->sndbuf_desc->len >> 1, + sock_net(&smc->sk)->smc.sysctl_autocorking_size); + + if (atomic_read(&conn->cdc_pend_tx_wr) == 0 || + smc_tx_prepared_sends(conn) > corking_size) + return false; + return true; +} + +static bool smc_tx_should_cork(struct smc_sock *smc, struct msghdr *msg) +{ + struct smc_connection *conn = &smc->conn; + + if (smc_should_autocork(smc)) + return true; + + /* for a corked socket defer the RDMA writes if + * sndbuf_space is still available. The applications + * should known how/when to uncork it. + */ + if ((msg->msg_flags & MSG_MORE || + smc_tx_is_corked(smc) || + msg->msg_flags & MSG_SENDPAGE_NOTLAST) && + atomic_read(&conn->sndbuf_space)) + return true; + + return false; +} + /* sndbuf producer: main API called by socket layer. * called under sock lock. */ @@ -236,15 +280,10 @@ int smc_tx_sendmsg(struct smc_sock *smc, struct msghdr *msg, size_t len) */ if ((msg->msg_flags & MSG_OOB) && !send_remaining) conn->urg_tx_pend = true; - if ((msg->msg_flags & MSG_MORE || smc_tx_is_corked(smc)) && - (atomic_read(&conn->sndbuf_space) > - (conn->sndbuf_desc->len >> 1))) - /* for a corked socket defer the RDMA writes if there - * is still sufficient sndbuf_space available - */ - queue_delayed_work(conn->lgr->tx_wq, &conn->tx_work, - SMC_TX_CORK_DELAY); - else + /* If we need to cork, do nothing and wait for the next + * sendmsg() call or push on tx completion + */ + if (!smc_tx_should_cork(smc, msg)) smc_tx_sndbuf_nonempty(conn); trace_smc_tx_sendmsg(smc, copylen); @@ -260,6 +299,22 @@ out_err: return rc; } +int smc_tx_sendpage(struct smc_sock *smc, struct page *page, int offset, + size_t size, int flags) +{ + struct msghdr msg = {.msg_flags = flags}; + char *kaddr = kmap(page); + struct kvec iov; + int rc; + + iov.iov_base = kaddr + offset; + iov.iov_len = size; + iov_iter_kvec(&msg.msg_iter, WRITE, &iov, 1, size); + rc = smc_tx_sendmsg(smc, &msg, size); + kunmap(page); + return rc; +} + /***************************** sndbuf consumer *******************************/ /* sndbuf consumer: actual data transfer of one target chunk with ISM write */ @@ -576,13 +631,26 @@ static int smcd_tx_sndbuf_nonempty(struct smc_connection *conn) return rc; } -int smc_tx_sndbuf_nonempty(struct smc_connection *conn) +static int __smc_tx_sndbuf_nonempty(struct smc_connection *conn) { - int rc; + struct smc_sock *smc = container_of(conn, struct smc_sock, conn); + int rc = 0; + + /* No data in the send queue */ + if (unlikely(smc_tx_prepared_sends(conn) <= 0)) + goto out; + + /* Peer don't have RMBE space */ + if (unlikely(atomic_read(&conn->peer_rmbe_space) <= 0)) { + SMC_STAT_RMB_TX_PEER_FULL(smc, !conn->lnk); + goto out; + } if (conn->killed || - conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) - return -EPIPE; /* connection being aborted */ + conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) { + rc = -EPIPE; /* connection being aborted */ + goto out; + } if (conn->lgr->is_smcd) rc = smcd_tx_sndbuf_nonempty(conn); else @@ -590,34 +658,72 @@ int smc_tx_sndbuf_nonempty(struct smc_connection *conn) if (!rc) { /* trigger socket release if connection is closing */ - struct smc_sock *smc = container_of(conn, struct smc_sock, - conn); smc_close_wake_tx_prepared(smc); } + +out: + return rc; +} + +int smc_tx_sndbuf_nonempty(struct smc_connection *conn) +{ + int rc; + + /* This make sure only one can send simultaneously to prevent wasting + * of CPU and CDC slot. + * Record whether someone has tried to push while we are pushing. + */ + if (atomic_inc_return(&conn->tx_pushing) > 1) + return 0; + +again: + atomic_set(&conn->tx_pushing, 1); + smp_wmb(); /* Make sure tx_pushing is 1 before real send */ + rc = __smc_tx_sndbuf_nonempty(conn); + + /* We need to check whether someone else have added some data into + * the send queue and tried to push but failed after the atomic_set() + * when we are pushing. + * If so, we need to push again to prevent those data hang in the send + * queue. + */ + if (unlikely(!atomic_dec_and_test(&conn->tx_pushing))) + goto again; + return rc; } /* Wakeup sndbuf consumers from process context - * since there is more data to transmit + * since there is more data to transmit. The caller + * must hold sock lock. */ -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; +} -out: +/* Wakeup sndbuf consumers from process context + * since there is more data to transmit in locked + * sock. + */ +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); + + lock_sock(&smc->sk); + smc_tx_pending(conn); release_sock(&smc->sk); } |