A fragment is marked completed by the PML when the peer signal the

completion of the RDMA operation associated with the fragment. The
PML will call the BML free which in turn will call the BTL free. The MX 
BTL will not release the fragment if it not tagged with 0xff.

This commit was SVN r12947.

ompi/mca/btl/mx/btl_mx.c

@@ -317,6 +317,9 @@ mca_btl_base_descriptor_t* mca_btl_mx_prepare_dst( struct mca_btl_base_module_t*
         return NULL;
     }
 
+    /* Allow the fragment to be recycled using the mca_btl_mx_free function */
+    frag->tag = 0xff;
+
     frag->base.des_dst = frag->segment;
     frag->base.des_dst_cnt = 1;