commit ba988f87f532cd2b8c4740aa8ec49056521ae833
author Chaitanya Huilgol <chaitanya.huilgol@gmail.com> Fri Jan 23 16:41:25 2015 +0530
committer Ilya Dryomov <idryomov@gmail.com> Thu Feb 19 13:31:40 2015 +0300
tree 14d535124a9146d02fa0a7e2f76d8778b0bce662
parent cf32bd9c86b6917d8446c00ea0081dde6e716a82

libceph: tcp_nodelay support

TCP_NODELAY socket option set on connection sockets,
disables Nagle’s algorithm and improves latency characteristics.
tcp_nodelay(default)/notcp_nodelay option flags provided to
enable/disable setting the socket option.

Signed-off-by: Chaitanya Huilgol <chaitanya.huilgol@sandisk.com>
[idryomov@redhat.com: NO_TCP_NODELAY -> TCP_NODELAY, minor adjustments]
Signed-off-by: Ilya Dryomov <idryomov@redhat.com>

net/ceph/messenger.c

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 33a2f201e..6b3f54e 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -510,6 +510,16 @@
 		return ret;
 	}
 
+	if (con->msgr->tcp_nodelay) {
+		int optval = 1;
+
+		ret = kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY,
+					(char *)&optval, sizeof(optval));
+		if (ret)
+			pr_err("kernel_setsockopt(TCP_NODELAY) failed: %d",
+			       ret);
+	}
+
 	sk_set_memalloc(sock->sk);
 
 	con->sock = sock;
@@ -2922,7 +2932,8 @@
 			struct ceph_entity_addr *myaddr,
 			u64 supported_features,
 			u64 required_features,
-			bool nocrc)
+			bool nocrc,
+			bool tcp_nodelay)
 {
 	msgr->supported_features = supported_features;
 	msgr->required_features = required_features;
@@ -2937,6 +2948,7 @@
 	get_random_bytes(&msgr->inst.addr.nonce, sizeof(msgr->inst.addr.nonce));
 	encode_my_addr(msgr);
 	msgr->nocrc = nocrc;
+	msgr->tcp_nodelay = tcp_nodelay;
 
 	atomic_set(&msgr->stopping, 0);