LU-6002 lnet: startup acceptor thread dynamically

With DLC it's possible to start up a system with no NIs that require
the acceptor thread, and thus it won't start.  Later on the user
can add an NI that requires the acceptor thread to start, it is
then necessary to start it up.

If the user removes a NI and as a result there are no more
NIs that require the acceptor thread then it should be stopped.
This patch adds logic in the dynamically adding and removing NIs
code to ensure the above logic is implemented.

Signed-off-by: Amir Shehata <amir.shehata@intel.com>
Change-Id: Iecada597d417dcb8991e9fb98f6844382295246a
Reviewed-on: http://review.whamcloud.com/13010
Tested-by: Jenkins
Reviewed-by: Isaac Huang <he.huang@intel.com>
Reviewed-by: Doug Oucharek <doug.s.oucharek@intel.com>
Tested-by: Maloo <hpdd-maloo@intel.com>
Reviewed-by: Oleg Drokin <oleg.drokin@intel.com>

diff --git a/lnet/lnet/acceptor.c b/lnet/lnet/acceptor.c
index 405c065..6bb9f85 100644 (file)
--- a/lnet/lnet/acceptor.c
+++ b/lnet/lnet/acceptor.c
@@ -47,7 +47,9 @@ static struct {
        int                     pta_shutdown;
        cfs_socket_t            *pta_sock;
        struct completion       pta_signal;
-} lnet_acceptor_state;
+} lnet_acceptor_state = {
+       .pta_shutdown = 1
+};
 
 int
 lnet_acceptor_port(void)
@@ -508,6 +510,10 @@ lnet_acceptor_start(void)
         long rc2;
         long secure;
 
+       /* if acceptor is already running return immediately */
+       if (!lnet_acceptor_state.pta_shutdown)
+               return 0;
+
         LASSERT (lnet_acceptor_state.pta_sock == NULL);
 
         rc = lnet_acceptor_get_tunables();
@@ -558,7 +564,7 @@ lnet_acceptor_start(void)
 void
 lnet_acceptor_stop(void)
 {
-       if (lnet_acceptor_state.pta_sock == NULL) /* not running */
+       if (lnet_acceptor_state.pta_shutdown) /* not running */
                return;
 
        lnet_acceptor_state.pta_shutdown = 1;

diff --git a/lnet/lnet/api-ni.c b/lnet/lnet/api-ni.c
index 2333899..75ff383 100644 (file)
--- a/lnet/lnet/api-ni.c
+++ b/lnet/lnet/api-ni.c
@@ -2020,6 +2020,16 @@ lnet_dyn_add_ni(lnet_pid_t requested_pid, char *nets,
        if (rc != 0)
                goto failed1;
 
+       if (ni->ni_lnd->lnd_accept != NULL) {
+               rc = lnet_acceptor_start();
+               if (rc < 0) {
+                       /* shutdown the ni that we just started */
+                       CERROR("Failed to start up acceptor thread\n");
+                       lnet_shutdown_lndni(ni);
+                       goto failed1;
+               }
+       }
+
        lnet_ping_target_update(pinfo, md_handle);
        LNET_MUTEX_UNLOCK(&the_lnet.ln_api_mutex);
 
@@ -2067,6 +2077,10 @@ lnet_dyn_del_ni(__u32 net)
        lnet_ni_decref_locked(ni, 0);
 
        lnet_shutdown_lndni(ni);
+
+       if (lnet_count_acceptor_nis() == 0)
+               lnet_acceptor_stop();
+
        lnet_ping_target_update(pinfo, md_handle);
        goto out;
 failed: