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>

2 files changed, 28 insertions, 2 deletions

diff --git a/net/ceph/ceph_common.c b/net/ceph/ceph_common.c
index 5d5ab67f516d..ec565508e904 100644
--- a/net/ceph/ceph_common.c
+++ b/net/ceph/ceph_common.c
@@ -239,6 +239,8 @@ enum {
         Opt_nocrc,
         Opt_cephx_require_signatures,
         Opt_nocephx_require_signatures,
+        Opt_tcp_nodelay,
+        Opt_notcp_nodelay,
 };
 
 static match_table_t opt_tokens = {
@@ -259,6 +261,8 @@ static match_table_t opt_tokens = {
         {Opt_nocrc, "nocrc"},
         {Opt_cephx_require_signatures, "cephx_require_signatures"},
         {Opt_nocephx_require_signatures, "nocephx_require_signatures"},
+        {Opt_tcp_nodelay, "tcp_nodelay"},
+        {Opt_notcp_nodelay, "notcp_nodelay"},
         {-1, NULL}
 };
 
@@ -457,6 +461,7 @@ ceph_parse_options(char *options, const char *dev_name,
                 case Opt_nocrc:
                         opt->flags |= CEPH_OPT_NOCRC;
                         break;
+
                 case Opt_cephx_require_signatures:
                         opt->flags &= ~CEPH_OPT_NOMSGAUTH;
                         break;
@@ -464,6 +469,13 @@ ceph_parse_options(char *options, const char *dev_name,
                         opt->flags |= CEPH_OPT_NOMSGAUTH;
                         break;
 
+                case Opt_tcp_nodelay:
+                        opt->flags |= CEPH_OPT_TCP_NODELAY;
+                        break;
+                case Opt_notcp_nodelay:
+                        opt->flags &= ~CEPH_OPT_TCP_NODELAY;
+                        break;
+
                 default:
                         BUG_ON(token);
                 }
@@ -518,10 +530,12 @@ struct ceph_client *ceph_create_client(struct ceph_options *opt, void *private,
         /* msgr */
         if (ceph_test_opt(client, MYIP))
                 myaddr = &client->options->my_addr;
+
         ceph_messenger_init(&client->msgr, myaddr,
                 client->supported_features,
                 client->required_features,
-                ceph_test_opt(client, NOCRC));
+                ceph_test_opt(client, NOCRC),
+                ceph_test_opt(client, TCP_NODELAY));
 
         /* subsystems */
         err = ceph_monc_init(&client->monc, client);
diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 33a2f201e460..6b3f54ed65ba 100644
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -510,6 +510,16 @@ static int ceph_tcp_connect(struct ceph_connection *con)
                 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 @@ void ceph_messenger_init(struct ceph_messenger *msgr,
                         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 @@ void ceph_messenger_init(struct ceph_messenger *msgr,
         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);