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, 5 insertions, 2 deletions

diff --git a/include/linux/ceph/libceph.h b/include/linux/ceph/libceph.h
index 8b11a79ca1cb..16fff9608848 100644
--- a/include/linux/ceph/libceph.h
+++ b/include/linux/ceph/libceph.h
@@ -30,8 +30,9 @@
 #define CEPH_OPT_MYIP             (1<<2) /* specified my ip */
 #define CEPH_OPT_NOCRC            (1<<3) /* no data crc on writes */
 #define CEPH_OPT_NOMSGAUTH        (1<<4) /* not require cephx message signature */
+#define CEPH_OPT_TCP_NODELAY      (1<<5) /* TCP_NODELAY on TCP sockets */
 
-#define CEPH_OPT_DEFAULT   (0)
+#define CEPH_OPT_DEFAULT   (CEPH_OPT_TCP_NODELAY)
 
 #define ceph_set_opt(client, opt) \
         (client)->options->flags |= CEPH_OPT_##opt;
diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index d9d396c16503..e15499422fdc 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -57,6 +57,7 @@ struct ceph_messenger {
 
         atomic_t stopping;
         bool nocrc;
+        bool tcp_nodelay;
 
         /*
          * the global_seq counts connections i (attempt to) initiate
@@ -264,7 +265,8 @@ extern 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);
 
 extern void ceph_con_init(struct ceph_connection *con, void *private,
                         const struct ceph_connection_operations *ops,