protocol/server: make listen backlog value as configurable

problem:

When we call listen from protocol/server, we are giving a
hard coded valie of 10 if it is not manually given.
With multiplexing, especially when glusterd restarts all
clients may try to connect to the server at a time.
Which will result in overflowing the queue, and kernel
will complain about the errors.

Solution:

This patch will introduce a volume set command to make backlog
value as a configurable. This patch also changes the default
values for backlog from 10 to 128. This changes is only applicable
for sockets listening from protocol.

Example:

gluster volume set <volname> transport.listen-backlog 1024

Note: 1 Brick has to be restarted to get this value in effect
      2 This changes won't be reflected in glusterd, or other
        xlators which calls listen. If you need, you have to
        add this option to the volfile.

Change-Id: I0c5a2bbf28b5db612f9979e7560e05dd82b41477
BUG: 1456405
Signed-off-by: Mohammed Rafi KC <rkavunga@redhat.com>
Reviewed-on: https://review.gluster.org/17411
Smoke: Gluster Build System <jenkins@build.gluster.org>
NetBSD-regression: NetBSD Build System <jenkins@build.gluster.org>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Reviewed-by: Raghavendra Talur <rtalur@redhat.com>
Reviewed-by: Atin Mukherjee <amukherj@redhat.com>
Reviewed-by: Niels de Vos <ndevos@redhat.com>
Reviewed-by: Jeff Darcy <jeff@pl.atyp.us>

1 files changed, 2 insertions, 0 deletions

diff --git a/rpc/rpc-transport/rdma/src/rdma.h b/rpc/rpc-transport/rdma/src/rdma.h
index 449861f075f..6bcf6bc6ef2 100644
--- a/rpc/rpc-transport/rdma/src/rdma.h
+++ b/rpc/rpc-transport/rdma/src/rdma.h
@@ -144,6 +144,7 @@ struct __gf_rdma_options {
 	uint8_t  attr_timeout;
 	uint8_t  attr_retry_cnt;
 	uint8_t  attr_rnr_retry;
+        uint32_t backlog;
 };
 typedef struct __gf_rdma_options gf_rdma_options_t;
 
@@ -383,6 +384,7 @@ struct __gf_rdma_private {
         pthread_mutex_t             recv_mutex;
         pthread_cond_t              recv_cond;
         gf_rdma_transport_entity_t  entity;
+        uint32_t                    backlog;
 };
 typedef struct __gf_rdma_private    gf_rdma_private_t;