From 2c3a5f9abb1dc5efdab8ba9a568b1661c65fd1e3 Mon Sep 17 00:00:00 2001 From: Andy Grover Date: Mon, 1 Mar 2010 16:10:40 -0800 Subject: [PATCH] RDS: Add flag for silent ops. Do atomic op before RDMA Add a flag to the API so users can indicate they want silent operations. This is needed because silent ops cannot be used with USE_ONCE MRs, so we can't just assume silent. Also, change send_xmit to do atomic op before rdma op if both are present, and centralize the hairy logic to determine if we want to attempt silent, or not. Signed-off-by: Andy Grover --- include/linux/rds.h | 1 + net/rds/rdma.c | 2 ++ net/rds/rds.h | 2 ++ net/rds/send.c | 55 +++++++++++++++++++++++++-------------------- 4 files changed, 36 insertions(+), 24 deletions(-) diff --git a/include/linux/rds.h b/include/linux/rds.h index 9239152abf7..109f1d34331 100644 --- a/include/linux/rds.h +++ b/include/linux/rds.h @@ -276,5 +276,6 @@ struct rds_rdma_notify { #define RDS_RDMA_USE_ONCE 0x0008 /* free MR after use */ #define RDS_RDMA_DONTWAIT 0x0010 /* Don't wait in SET_BARRIER */ #define RDS_RDMA_NOTIFY_ME 0x0020 /* Notify when operation completes */ +#define RDS_RDMA_SILENT 0x0040 /* Do not interrupt remote */ #endif /* IB_RDS_H */ diff --git a/net/rds/rdma.c b/net/rds/rdma.c index 5ba51468443..48781fe4431 100644 --- a/net/rds/rdma.c +++ b/net/rds/rdma.c @@ -559,6 +559,7 @@ int rds_cmsg_rdma_args(struct rds_sock *rs, struct rds_message *rm, op->op_write = !!(args->flags & RDS_RDMA_READWRITE); op->op_fence = !!(args->flags & RDS_RDMA_FENCE); op->op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME); + op->op_silent = !!(args->flags & RDS_RDMA_SILENT); op->op_active = 1; op->op_recverr = rs->rs_recverr; WARN_ON(!nr_pages); @@ -747,6 +748,7 @@ int rds_cmsg_atomic(struct rds_sock *rs, struct rds_message *rm, } rm->atomic.op_notify = !!(args->flags & RDS_RDMA_NOTIFY_ME); + rm->atomic.op_silent = !!(args->flags & RDS_RDMA_SILENT); rm->atomic.op_active = 1; rm->atomic.op_recverr = rs->rs_recverr; rm->atomic.op_sg = rds_message_alloc_sgs(rm, 1); diff --git a/net/rds/rds.h b/net/rds/rds.h index 46d190d0854..23b921000e7 100644 --- a/net/rds/rds.h +++ b/net/rds/rds.h @@ -319,6 +319,7 @@ struct rds_message { unsigned int op_notify:1; unsigned int op_recverr:1; unsigned int op_mapped:1; + unsigned int op_silent:1; unsigned int op_active:1; struct scatterlist *op_sg; struct rds_notifier *op_notifier; @@ -333,6 +334,7 @@ struct rds_message { unsigned int op_notify:1; unsigned int op_recverr:1; unsigned int op_mapped:1; + unsigned int op_silent:1; unsigned int op_active:1; unsigned int op_bytes; unsigned int op_nents; diff --git a/net/rds/send.c b/net/rds/send.c index cdca9747fcb..38567f3ee7e 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -250,42 +250,50 @@ int rds_send_xmit(struct rds_connection *conn) conn->c_xmit_rm = rm; } - if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) { - ret = conn->c_trans->xmit_atomic(conn, rm); + /* The transport either sends the whole rdma or none of it */ + if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) { + ret = conn->c_trans->xmit_rdma(conn, &rm->rdma); if (ret) break; - conn->c_xmit_atomic_sent = 1; + conn->c_xmit_rdma_sent = 1; + /* The transport owns the mapped memory for now. * You can't unmap it while it's on the send queue */ set_bit(RDS_MSG_MAPPED, &rm->m_flags); - - /* - * This is evil, muahaha. - * We permit 0-byte sends. (rds-ping depends on this.) - * BUT if there is an atomic op and no sent data, - * we turn off sending the header, to achieve - * "silent" atomics. - * But see below; RDMA op might toggle this back on! - */ - if (rm->data.op_nents == 0) - rm->data.op_active = 0; } - /* The transport either sends the whole rdma or none of it */ - if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) { - ret = conn->c_trans->xmit_rdma(conn, &rm->rdma); + if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) { + ret = conn->c_trans->xmit_atomic(conn, rm); if (ret) break; - conn->c_xmit_rdma_sent = 1; - - /* rdmas need data sent, even if just the header */ - rm->data.op_active = 1; - + conn->c_xmit_atomic_sent = 1; /* The transport owns the mapped memory for now. * You can't unmap it while it's on the send queue */ set_bit(RDS_MSG_MAPPED, &rm->m_flags); } + /* + * A number of cases require an RDS header to be sent + * even if there is no data. + * We permit 0-byte sends; rds-ping depends on this. + * However, if there are exclusively attached silent ops, + * we skip the hdr/data send, to enable silent operation. + */ + if (rm->data.op_nents == 0) { + int ops_present; + int all_ops_are_silent = 1; + + ops_present = (rm->atomic.op_active || rm->rdma.op_active); + if (rm->atomic.op_active && !rm->atomic.op_silent) + all_ops_are_silent = 0; + if (rm->rdma.op_active && !rm->rdma.op_silent) + all_ops_are_silent = 0; + + if (ops_present && all_ops_are_silent + && !rm->m_rdma_cookie) + rm->data.op_active = 0; + } + if (rm->data.op_active && !conn->c_xmit_data_sent) { ret = conn->c_trans->xmit(conn, rm, conn->c_xmit_hdr_off, @@ -1009,8 +1017,7 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg, if (ret) goto out; - if ((rm->m_rdma_cookie || rm->rdma.op_active) && - !conn->c_trans->xmit_rdma) { + if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) { if (printk_ratelimit()) printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n", &rm->rdma, conn->c_trans->xmit_rdma); -- 2.39.3