add mca param to enable/disable mxm

This commit was SVN r25813.

ompi/mca/mtl/mxm/mtl_mxm_component.c

@@ -72,6 +72,12 @@ static int ompi_mtl_mxm_component_register(void)
                            0,
                            &ompi_mtl_mxm.verbose);
 
+    mca_base_param_reg_int(&mca_mtl_mxm_component.super.mtl_version, "enable",
+                           "Enable/Disable MXM component",
+                           false, false,
+                           1,
+                           &ompi_mtl_mxm.enabled);
+
     return OMPI_SUCCESS;
 }
 
@@ -82,6 +88,11 @@ static int ompi_mtl_mxm_component_open(void)
     mca_mtl_mxm_output = opal_output_open(NULL);
     opal_output_set_verbosity(mca_mtl_mxm_output, ompi_mtl_mxm.verbose);
 
+    if (0 == ompi_mtl_mxm.enabled) {
+        MXM_VERBOSE(1, "MTL/MXM was disabled on user request");
+        return OPAL_ERR_NOT_AVAILABLE;
+    }
+
     mxm_fill_context_opts(&ompi_mtl_mxm.mxm_opts);
     err = mxm_init(&ompi_mtl_mxm.mxm_opts, &ompi_mtl_mxm.mxm_context);
     if (MXM_OK != err) {

ompi/mca/mtl/mxm/mtl_mxm_types.h

@@ -27,6 +27,7 @@ BEGIN_C_DECLS
 typedef struct mca_mtl_mxm_module_t {
     mca_mtl_base_module_t super; /**< base MTL interface */
     int                   verbose;
+    int                   enabled;
     mxm_h                 mxm_context;
     mxm_context_opts_t    mxm_opts;
     mxm_ep_h              ep;