LU-9448 lnet: handle empty CPTs

[fs/lustre-release.git] / lnet / klnds / o2iblnd / o2iblnd.c

diff --git a/lnet/klnds/o2iblnd/o2iblnd.c b/lnet/klnds/o2iblnd/o2iblnd.c
index 70ed74f..12dade5 100644 (file)
--- a/lnet/klnds/o2iblnd/o2iblnd.c
+++ b/lnet/klnds/o2iblnd/o2iblnd.c
@@ -698,6 +698,36 @@ kiblnd_get_completion_vector(kib_conn_t *conn, int cpt)
        return 1;
 }
 
+/*
+ * Get the scheduler bound to this CPT. If the scheduler has no
+ * threads, which means that the CPT has no CPUs, then grab the
+ * next scheduler that we can use.
+ *
+ * This case would be triggered if a NUMA node is configured with
+ * no associated CPUs.
+ */
+static struct kib_sched_info *
+kiblnd_get_scheduler(int cpt)
+{
+       struct kib_sched_info *sched;
+       int i;
+
+       sched = kiblnd_data.kib_scheds[cpt];
+
+       if (sched->ibs_nthreads > 0)
+               return sched;
+
+       cfs_percpt_for_each(sched, i, kiblnd_data.kib_scheds) {
+               if (sched->ibs_nthreads > 0) {
+                       CDEBUG(D_NET, "scheduler[%d] has no threads. selected scheduler[%d]\n",
+                                       cpt, sched->ibs_cpt);
+                       return sched;
+               }
+       }
+
+       return NULL;
+}
+
 kib_conn_t *
 kiblnd_create_conn(kib_peer_ni_t *peer_ni, struct rdma_cm_id *cmid,
                   int state, int version)
@@ -730,9 +760,18 @@ kiblnd_create_conn(kib_peer_ni_t *peer_ni, struct rdma_cm_id *cmid,
        dev = net->ibn_dev;
 
        cpt = lnet_cpt_of_nid(peer_ni->ibp_nid, peer_ni->ibp_ni);
-       sched = kiblnd_data.kib_scheds[cpt];
+       sched = kiblnd_get_scheduler(cpt);
+
+       if (sched == NULL) {
+               CERROR("no schedulers available. node is unhealthy\n");
+               goto failed_0;
+       }
 
-       LASSERT(sched->ibs_nthreads > 0);
+       /*
+        * The cpt might have changed if we ended up selecting a non cpt
+        * native scheduler. So use the scheduler's cpt instead.
+        */
+       cpt = sched->ibs_cpt;
 
        LIBCFS_CPT_ALLOC(init_qp_attr, lnet_cpt_table(), cpt,
                         sizeof(*init_qp_attr));