We are *definitely* counting cycles as closely as DaveM, so
ensure hwcache alignment for our recv ring control structs.
Signed-off-by: Andy Grover <andy.grover@oracle.com>
 
        rds_ib_incoming_slab = kmem_cache_create("rds_ib_incoming",
                                        sizeof(struct rds_ib_incoming),
-                                       0, 0, NULL);
+                                       0, SLAB_HWCACHE_ALIGN, NULL);
        if (!rds_ib_incoming_slab)
                goto out;
 
        rds_ib_frag_slab = kmem_cache_create("rds_ib_frag",
                                        sizeof(struct rds_page_frag),
-                                       0, 0, NULL);
+                                       0, SLAB_HWCACHE_ALIGN, NULL);
        if (!rds_ib_frag_slab)
                kmem_cache_destroy(rds_ib_incoming_slab);
        else