[PATCH v2 net-next 3/3] RDS-TCP: Set up MSG_MORE and MSG_SENDPAGE_NOTLAST as appropriate in rds_tcp_xmit

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From	Sowmini Varadhan <sowmini.varadhan@oracle.com>
Newsgroups	linux.kernel
Subject	[PATCH v2 net-next 3/3] RDS-TCP: Set up MSG_MORE and MSG_SENDPAGE_NOTLAST as appropriate in rds_tcp_xmit
Date	Wed, 30 Sep 2015 23:00:02 +0200
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For the same reasons as commit 2f5338442425 ("tcp: allow splice() to
build full TSO packets") and commit 35f9c09fe9c7 ("tcp: tcp_sendpages()
should call tcp_push() once"), rds_tcp_xmit may have multiple pages to
send, so use the MSG_MORE and MSG_SENDPAGE_NOTLAST as hints to
tcp_sendpage()

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
---
v2: Sergei Shtylov, Santosh Shilimkar comments (some parens retained for
    readability)

 net/rds/tcp_send.c |    8 +++++++-
 1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/net/rds/tcp_send.c b/net/rds/tcp_send.c
index 53b17ca..2894e60 100644
--- a/net/rds/tcp_send.c
+++ b/net/rds/tcp_send.c
@@ -83,6 +83,7 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
 	struct rds_tcp_connection *tc = conn->c_transport_data;
 	int done = 0;
 	int ret = 0;
+	int more;
 
 	if (hdr_off == 0) {
 		/*
@@ -116,12 +117,15 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
 			goto out;
 	}
 
+	more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0;
 	while (sg < rm->data.op_nents) {
+		int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
+
 		ret = tc->t_sock->ops->sendpage(tc->t_sock,
 						sg_page(&rm->data.op_sg[sg]),
 						rm->data.op_sg[sg].offset + off,
 						rm->data.op_sg[sg].length - off,
-						MSG_DONTWAIT|MSG_NOSIGNAL);
+						flags);
 		rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
 			 rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
 			 ret);
@@ -134,6 +138,8 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
 			off = 0;
 			sg++;
 		}
+		if (sg == rm->data.op_nents - 1)
+			more = 0;
 	}
 
 out:
-- 
1.7.1

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Thread

[PATCH v2 net-next 0/3]  RDS: RDS-TCP perf enhancements Sowmini Varadhan <sowmini.varadhan@oracle.com> - 2015-09-30 23:00 +0200
  [PATCH v2 net-next 3/3] RDS-TCP: Set up MSG_MORE and MSG_SENDPAGE_NOTLAST as appropriate in rds_tcp_xmit Sowmini Varadhan <sowmini.varadhan@oracle.com> - 2015-09-30 23:00 +0200
  [PATCH v2 net-next 1/3] RDS: Use a single TCP socket for both send and receive. Sowmini Varadhan <sowmini.varadhan@oracle.com> - 2015-09-30 23:00 +0200
  [PATCH v2 net-next 2/3] RDS-TCP: Do not bloat sndbuf/rcvbuf in rds_tcp_tune Sowmini Varadhan <sowmini.varadhan@oracle.com> - 2015-09-30 23:00 +0200
  Re: [PATCH v2 net-next 0/3] RDS: RDS-TCP perf enhancements santosh shilimkar <santosh.shilimkar@oracle.com> - 2015-10-01 01:30 +0200
  Re: [PATCH v2 net-next 0/3] RDS: RDS-TCP perf enhancements David Miller <davem@davemloft.net> - 2015-10-05 12:30 +0200

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