diff --git a/ompi/mca/bml/bml.h b/ompi/mca/bml/bml.h
index f1e2a089b8..0d0c4bd5e4 100644
--- a/ompi/mca/bml/bml.h
+++ b/ompi/mca/bml/bml.h
@@ -259,8 +259,8 @@ typedef struct mca_bml_base_endpoint_t mca_bml_base_endpoint_t;
     
 OMPI_DECLSPEC OBJ_CLASS_DECLARATION(mca_bml_base_endpoint_t);
 
-static inline void mca_bml_base_alloc(mca_bml_base_btl_t* bml_btl, mca_btl_base_descriptor_t** des, uint8_t order, size_t size) { 
-    *des = bml_btl->btl_alloc(bml_btl->btl, bml_btl->btl_endpoint, order, size);
+static inline void mca_bml_base_alloc(mca_bml_base_btl_t* bml_btl, mca_btl_base_descriptor_t** des, uint8_t order, size_t size, uint32_t flags) { 
+    *des = bml_btl->btl_alloc(bml_btl->btl, bml_btl->btl_endpoint, order, size, flags);
 }
 
 static inline void mca_bml_base_free(mca_bml_base_btl_t* bml_btl, mca_btl_base_descriptor_t* des) { 
@@ -318,6 +318,7 @@ static inline void mca_bml_base_prepare_src(mca_bml_base_btl_t* bml_btl,
                                             uint8_t order,
                                             size_t reserve, 
                                             size_t *size,
+                                            uint32_t flags,
                                             mca_btl_base_descriptor_t** des) { 
     *des = bml_btl->btl_prepare_src(
                                    bml_btl->btl, 
@@ -326,7 +327,8 @@ static inline void mca_bml_base_prepare_src(mca_bml_base_btl_t* bml_btl,
                                    conv,
                                    order,
                                    reserve,
-                                   size
+                                   size,
+                                   flags
                                    );
     if( OPAL_LIKELY((*des) != NULL) ) { 
         (*des)->des_context = (void*) bml_btl;
@@ -338,7 +340,8 @@ static inline void mca_bml_base_prepare_dst(mca_bml_base_btl_t* bml_btl,
                                             struct ompi_convertor_t* conv, 
                                             uint8_t order,
                                             size_t reserve, 
-                                            size_t *size, 
+                                            size_t *size,
+                                            uint32_t flags,
                                             mca_btl_base_descriptor_t** des) { 
     *des = bml_btl->btl_prepare_dst(
                                    bml_btl->btl, 
@@ -347,7 +350,8 @@ static inline void mca_bml_base_prepare_dst(mca_bml_base_btl_t* bml_btl,
                                    conv,
                                    order,
                                    reserve,
-                                   size
+                                   size,
+                                   flags
                                    );
     if( OPAL_LIKELY((*des) != NULL) ) { 
         (*des)->des_context = (void*) bml_btl;  
diff --git a/ompi/mca/btl/btl.h b/ompi/mca/btl/btl.h
index 463e2626b8..7da07c3f89 100644
--- a/ompi/mca/btl/btl.h
+++ b/ompi/mca/btl/btl.h
@@ -239,7 +239,7 @@ struct mca_btl_base_descriptor_t {
     mca_btl_base_completion_fn_t des_cbfunc;  /**< local callback function */ 
     void* des_cbdata;                         /**< opaque callback data */
     void* des_context;                        /**< more opaque callback data */
-    int32_t des_flags;                        /**< hints to BTL */
+    uint32_t des_flags;                       /**< hints to BTL */
     /** order value, this is only 
         valid in the local completion callback 
         and may be used in subsequent calls to 
@@ -517,7 +517,8 @@ typedef mca_btl_base_descriptor_t* (*mca_btl_base_module_alloc_fn_t)(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size
+    size_t size,
+    uint32_t flags
 );
 
 /**
@@ -571,7 +572,8 @@ typedef struct mca_btl_base_descriptor_t* (*mca_btl_base_module_prepare_fn_t)(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 /**
diff --git a/ompi/mca/btl/elan/btl_elan.c b/ompi/mca/btl/elan/btl_elan.c
index 3380356444..e95bcd5fd8 100644
--- a/ompi/mca/btl/elan/btl_elan.c
+++ b/ompi/mca/btl/elan/btl_elan.c
@@ -225,7 +225,8 @@ mca_btl_base_descriptor_t* mca_btl_elan_alloc(
         struct mca_btl_base_module_t* btl,
         struct mca_btl_base_endpoint_t* peer,
         uint8_t order,
-        size_t size )
+        size_t size,
+        uint32_t flags)
 {
     mca_btl_elan_frag_t* frag;
     int rc;
@@ -282,7 +283,8 @@ mca_btl_base_descriptor_t* mca_btl_elan_prepare_src( struct mca_btl_base_module_
 						      struct ompi_convertor_t* convertor,
 		        		              uint8_t order,
 						      size_t reserve,
-						      size_t* size )
+						      size_t* size,
+                              uint32_t flags)
 
 
 {
@@ -374,7 +376,8 @@ mca_btl_base_descriptor_t* mca_btl_elan_prepare_dst( struct mca_btl_base_module_
 						     struct ompi_convertor_t* convertor,
                                                      uint8_t order,
 						     size_t reserve,
-						     size_t* size )
+						     size_t* size,
+                             uint32_t flags)
 {
 
     mca_btl_elan_frag_t* frag;
diff --git a/ompi/mca/btl/elan/btl_elan.h b/ompi/mca/btl/elan/btl_elan.h
index ea121ebffb..392390e9db 100644
--- a/ompi/mca/btl/elan/btl_elan.h
+++ b/ompi/mca/btl/elan/btl_elan.h
@@ -293,7 +293,8 @@ extern mca_btl_base_descriptor_t* mca_btl_elan_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* peer,
     uint8_t order,
-    size_t size); 
+    size_t size,
+    uint32_t flags); 
 
 
 /**
@@ -329,7 +330,8 @@ mca_btl_base_descriptor_t* mca_btl_elan_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 extern mca_btl_base_descriptor_t* mca_btl_elan_prepare_dst( 
@@ -339,7 +341,8 @@ extern mca_btl_base_descriptor_t* mca_btl_elan_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size); 
+    size_t* size,
+    uint32_t flags); 
 
 
 extern bufdesc_t * elan_ipeek(mca_btl_elan_module_t* elan_btl);
diff --git a/ompi/mca/btl/gm/btl_gm.c b/ompi/mca/btl/gm/btl_gm.c
index 0e00bb0315..a82084d2fd 100644
--- a/ompi/mca/btl/gm/btl_gm.c
+++ b/ompi/mca/btl/gm/btl_gm.c
@@ -204,7 +204,8 @@ mca_btl_base_descriptor_t* mca_btl_gm_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_gm_module_t* gm_btl = (mca_btl_gm_module_t*) btl; 
     mca_btl_gm_frag_t* frag;
@@ -271,7 +272,8 @@ mca_btl_base_descriptor_t* mca_btl_gm_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 )
 {
     mca_btl_gm_frag_t *frag = NULL;
@@ -390,7 +392,8 @@ mca_btl_base_descriptor_t* mca_btl_gm_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
 #if (OMPI_MCA_BTL_GM_HAVE_RDMA_GET || OMPI_MCA_BTL_GM_HAVE_RDMA_PUT)
     mca_btl_gm_frag_t* frag;
diff --git a/ompi/mca/btl/gm/btl_gm.h b/ompi/mca/btl/gm/btl_gm.h
index 1eb41e5bec..51e88a5d31 100644
--- a/ompi/mca/btl/gm/btl_gm.h
+++ b/ompi/mca/btl/gm/btl_gm.h
@@ -294,7 +294,8 @@ extern mca_btl_base_descriptor_t* mca_btl_gm_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size); 
+    size_t size,
+    uint32_t flags); 
 
 
 /**
@@ -330,7 +331,8 @@ mca_btl_base_descriptor_t* mca_btl_gm_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 extern mca_btl_base_descriptor_t* mca_btl_gm_prepare_dst( 
@@ -340,7 +342,8 @@ extern mca_btl_base_descriptor_t* mca_btl_gm_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size); 
+    size_t* size,
+    uint32_t flags); 
 
 /**
  * Fault Tolerance Event Notification Function
diff --git a/ompi/mca/btl/mx/btl_mx.c b/ompi/mca/btl/mx/btl_mx.c
index 005a67354d..64da95a4b6 100644
--- a/ompi/mca/btl/mx/btl_mx.c
+++ b/ompi/mca/btl/mx/btl_mx.c
@@ -165,7 +165,8 @@ int mca_btl_mx_register( struct mca_btl_base_module_t* btl,
 mca_btl_base_descriptor_t* mca_btl_mx_alloc( struct mca_btl_base_module_t* btl,
                                              struct mca_btl_base_endpoint_t* endpoint,
                                              uint8_t order,
-                                             size_t size )
+                                             size_t size,
+                                             uint32_t flags)
 {
     mca_btl_mx_module_t* mx_btl = (mca_btl_mx_module_t*) btl; 
     mca_btl_mx_frag_t* frag;
@@ -216,7 +217,8 @@ mca_btl_mx_prepare_src( struct mca_btl_base_module_t* btl,
                         struct ompi_convertor_t* convertor,
                         uint8_t order,
                         size_t reserve,
-                        size_t* size )
+                        size_t* size,
+                        uint32_t flags)
 {
     mca_btl_mx_frag_t* frag;
     struct iovec iov;
@@ -299,7 +301,8 @@ mca_btl_base_descriptor_t* mca_btl_mx_prepare_dst( struct mca_btl_base_module_t*
                                                    struct ompi_convertor_t* convertor,
                                                    uint8_t order,
                                                    size_t reserve,
-                                                   size_t* size)
+                                                   size_t* size,
+                                                   uint32_t flags)
 {
     mca_btl_mx_module_t* mx_btl = (mca_btl_mx_module_t*)btl;
     mca_btl_mx_frag_t* frag;
diff --git a/ompi/mca/btl/mx/btl_mx.h b/ompi/mca/btl/mx/btl_mx.h
index c40561792a..53c2bfec14 100644
--- a/ompi/mca/btl/mx/btl_mx.h
+++ b/ompi/mca/btl/mx/btl_mx.h
@@ -256,7 +256,8 @@ extern int mca_btl_mx_register(
 mca_btl_base_descriptor_t* mca_btl_mx_alloc( struct mca_btl_base_module_t* btl,
                                              struct mca_btl_base_endpoint_t* endpoint,
                                              uint8_t order,
-                                             size_t size );
+                                             size_t size,
+                                             uint32_t flags);
 
 
 /**
@@ -290,7 +291,8 @@ mca_btl_mx_prepare_src( struct mca_btl_base_module_t* btl,
                         struct ompi_convertor_t* convertor,
                         uint8_t order,
                         size_t reserve,
-                        size_t* size );
+                        size_t* size,
+                        uint32_t flags);
 
 mca_btl_base_descriptor_t*
 mca_btl_mx_prepare_dst( struct mca_btl_base_module_t* btl, 
@@ -299,7 +301,8 @@ mca_btl_mx_prepare_dst( struct mca_btl_base_module_t* btl,
                         struct ompi_convertor_t* convertor,
                         uint8_t order,
                         size_t reserve,
-                        size_t* size );
+                        size_t* size,
+                        uint32_t flags);
 
 /**
  * Fault Tolerance Event Notification Function
diff --git a/ompi/mca/btl/ofud/btl_ofud.c b/ompi/mca/btl/ofud/btl_ofud.c
index cb0a9382e9..cfa437fd25 100644
--- a/ompi/mca/btl/ofud/btl_ofud.c
+++ b/ompi/mca/btl/ofud/btl_ofud.c
@@ -220,7 +220,8 @@ int mca_btl_ud_register(struct mca_btl_base_module_t* btl,
 mca_btl_base_descriptor_t* mca_btl_ud_alloc(struct mca_btl_base_module_t* btl,
                                             struct mca_btl_base_endpoint_t* endpoint,
                                             uint8_t order,
-                                            size_t size)
+                                            size_t size,
+                                            uint32_t flags)
 {
     mca_btl_ud_frag_t* frag = NULL;
     int rc;
@@ -297,7 +298,8 @@ mca_btl_base_descriptor_t* mca_btl_ud_prepare_src(
                                     struct ompi_convertor_t* convertor,
                                     uint8_t order,
                                     size_t reserve,
-                                    size_t* size)
+                                    size_t* size,
+                                    uint32_t flags)
 {
     mca_btl_ud_frag_t* frag = NULL;
     struct iovec iov;
diff --git a/ompi/mca/btl/ofud/btl_ofud.h b/ompi/mca/btl/ofud/btl_ofud.h
index 9fb2d0b526..6b80f27f6c 100644
--- a/ompi/mca/btl/ofud/btl_ofud.h
+++ b/ompi/mca/btl/ofud/btl_ofud.h
@@ -296,7 +296,8 @@ extern mca_btl_base_descriptor_t* mca_btl_ud_alloc(
                                               struct mca_btl_base_module_t* btl,
                                               struct mca_btl_base_endpoint_t* endpoint,
                                               uint8_t order,
-                                              size_t size);
+                                              size_t size,
+                                              uint32_t flags);
 
 
 /**
@@ -325,7 +326,8 @@ mca_btl_base_descriptor_t* mca_btl_ud_prepare_src(
                                     struct ompi_convertor_t* convertor,
                                     uint8_t order,
                                     size_t reserve,
-                                    size_t* size);
+                                    size_t* size,
+                                    uint32_t flags);
 
 
 
diff --git a/ompi/mca/btl/openib/btl_openib.c b/ompi/mca/btl/openib/btl_openib.c
index 7c4a19338b..d54717682d 100644
--- a/ompi/mca/btl/openib/btl_openib.c
+++ b/ompi/mca/btl/openib/btl_openib.c
@@ -556,7 +556,8 @@ mca_btl_base_descriptor_t* mca_btl_openib_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* ep,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_openib_module_t *obtl = (mca_btl_openib_module_t*)btl;
     int qp = frag_size_to_order(obtl, size);
@@ -707,8 +708,8 @@ mca_btl_base_descriptor_t* mca_btl_openib_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
-)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_openib_module_t *openib_btl;
     mca_btl_openib_reg_t *openib_reg;
@@ -779,7 +780,7 @@ mca_btl_base_descriptor_t* mca_btl_openib_prepare_src(
   
     frag = (mca_btl_openib_com_frag_t*)(reserve ?
             ib_frag_alloc(openib_btl, max_data + reserve, order) :
-            mca_btl_openib_alloc(btl, endpoint, order, max_data));
+            mca_btl_openib_alloc(btl, endpoint, order, max_data, flags));
 
     if(NULL == frag)
         return NULL;
@@ -815,7 +816,8 @@ mca_btl_base_descriptor_t* mca_btl_openib_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_openib_module_t *openib_btl;
     mca_btl_openib_com_frag_t *frag;
diff --git a/ompi/mca/btl/openib/btl_openib.h b/ompi/mca/btl/openib/btl_openib.h
index 4cfccc24e2..1a74952996 100644
--- a/ompi/mca/btl/openib/btl_openib.h
+++ b/ompi/mca/btl/openib/btl_openib.h
@@ -480,7 +480,8 @@ extern mca_btl_base_descriptor_t* mca_btl_openib_alloc(
         struct mca_btl_base_module_t* btl,
         struct mca_btl_base_endpoint_t* endpoint,
         uint8_t order,
-        size_t size); 
+        size_t size,
+        uint32_t flags); 
     
 
 /**
@@ -508,7 +509,8 @@ mca_btl_base_descriptor_t* mca_btl_openib_prepare_src(
                                                       struct ompi_convertor_t* convertor,
                                                       uint8_t order,
                                                       size_t reserve,
-                                                      size_t* size
+                                                      size_t* size,
+                                                      uint32_t flags
                                                       );
 
 /**
@@ -524,7 +526,8 @@ extern mca_btl_base_descriptor_t* mca_btl_openib_prepare_dst(
                                                              struct ompi_convertor_t* convertor,
                                                              uint8_t order,
                                                              size_t reserve,
-                                                             size_t* size); 
+                                                             size_t* size,
+                                                             uint32_t flags); 
 
 extern void mca_btl_openib_frag_progress_pending_put_get(
         struct mca_btl_base_endpoint_t*, const int);
diff --git a/ompi/mca/btl/portals/btl_portals.c b/ompi/mca/btl/portals/btl_portals.c
index b26e969cac..eb9eecc558 100644
--- a/ompi/mca/btl/portals/btl_portals.c
+++ b/ompi/mca/btl/portals/btl_portals.c
@@ -243,7 +243,8 @@ mca_btl_base_descriptor_t*
 mca_btl_portals_alloc(struct mca_btl_base_module_t* btl_base,
                       struct mca_btl_base_endpoint_t* endpoint,
                       uint8_t order,
-                      size_t size)
+                      size_t size,
+                      uint32_t flags)
 {
     int rc;
     mca_btl_portals_frag_t* frag;
@@ -311,7 +312,8 @@ mca_btl_portals_prepare_src(struct mca_btl_base_module_t* btl_base,
                             struct ompi_convertor_t* convertor,
                             uint8_t order,
                             size_t reserve,
-                            size_t* size)
+                            size_t* size,
+                            uint32_t flags)
 {
     mca_btl_portals_frag_t* frag;
     size_t max_data = *size;
@@ -433,7 +435,8 @@ mca_btl_portals_prepare_dst(struct mca_btl_base_module_t* btl_base,
                             struct ompi_convertor_t* convertor,
                             uint8_t order,
                             size_t reserve,
-                            size_t* size)
+                            size_t* size,
+                            uint32_t flags)
 {
     mca_btl_portals_frag_t* frag;
     ptl_md_t md;
diff --git a/ompi/mca/btl/portals/btl_portals.h b/ompi/mca/btl/portals/btl_portals.h
index 39c7a69fd7..947a62ae3d 100644
--- a/ompi/mca/btl/portals/btl_portals.h
+++ b/ompi/mca/btl/portals/btl_portals.h
@@ -174,7 +174,8 @@ mca_btl_base_descriptor_t*
 mca_btl_portals_alloc(struct mca_btl_base_module_t* btl_base, 
                       struct mca_btl_base_endpoint_t* endpoint,
                       uint8_t order,
-                      size_t size); 
+                      size_t size,
+                      uint32_t flags); 
 
 int mca_btl_portals_free(struct mca_btl_base_module_t* btl_base, 
                          mca_btl_base_descriptor_t* des); 
@@ -186,7 +187,8 @@ mca_btl_portals_prepare_src(struct mca_btl_base_module_t* btl_base,
                             struct ompi_convertor_t* convertor,
                             uint8_t order,
                             size_t reserve,
-                            size_t* size);
+                            size_t* size,
+                            uint32_t flags);
 
 mca_btl_base_descriptor_t* 
 mca_btl_portals_prepare_dst(struct mca_btl_base_module_t* btl_base, 
@@ -195,7 +197,8 @@ mca_btl_portals_prepare_dst(struct mca_btl_base_module_t* btl_base,
                             struct ompi_convertor_t* convertor,
                             uint8_t order,
                             size_t reserve,
-                            size_t* size); 
+                            size_t* size,
+                            uint32_t flags); 
 
 int mca_btl_portals_send(struct mca_btl_base_module_t* btl_base,
                          struct mca_btl_base_endpoint_t* btl_peer,
diff --git a/ompi/mca/btl/sctp/btl_sctp.c b/ompi/mca/btl/sctp/btl_sctp.c
index 12d5eae346..ff28d12fd2 100644
--- a/ompi/mca/btl/sctp/btl_sctp.c
+++ b/ompi/mca/btl/sctp/btl_sctp.c
@@ -186,7 +186,8 @@ mca_btl_base_descriptor_t* mca_btl_sctp_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_sctp_frag_t* frag;
     int rc;
@@ -241,7 +242,8 @@ mca_btl_base_descriptor_t* mca_btl_sctp_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_sctp_frag_t* frag;
     struct iovec iov;
@@ -341,7 +343,8 @@ mca_btl_base_descriptor_t* mca_btl_sctp_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_sctp_frag_t* frag;
     ptrdiff_t lb;
diff --git a/ompi/mca/btl/sctp/btl_sctp.h b/ompi/mca/btl/sctp/btl_sctp.h
index c6ec36476a..2ab9b96156 100644
--- a/ompi/mca/btl/sctp/btl_sctp.h
+++ b/ompi/mca/btl/sctp/btl_sctp.h
@@ -294,7 +294,8 @@ extern mca_btl_base_descriptor_t* mca_btl_sctp_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size); 
+    size_t size,
+    uint32_t flags); 
 
 
 /**
@@ -330,7 +331,8 @@ mca_btl_base_descriptor_t* mca_btl_sctp_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 extern mca_btl_base_descriptor_t* mca_btl_sctp_prepare_dst( 
@@ -340,7 +342,8 @@ extern mca_btl_base_descriptor_t* mca_btl_sctp_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size); 
+    size_t* size,
+    uint32_t flags); 
 
 
 #if defined(c_plusplus) || defined(__cplusplus)
diff --git a/ompi/mca/btl/self/btl_self.c b/ompi/mca/btl/self/btl_self.c
index bcf79365ec..0b8bae2733 100644
--- a/ompi/mca/btl/self/btl_self.c
+++ b/ompi/mca/btl/self/btl_self.c
@@ -152,7 +152,8 @@ mca_btl_base_descriptor_t* mca_btl_self_alloc(
         struct mca_btl_base_module_t* btl,
         struct mca_btl_base_endpoint_t* endpoint,
         uint8_t order,
-        size_t size )
+        size_t size,
+        uint32_t flags)
 {
     mca_btl_self_frag_t* frag;
     int rc;
@@ -211,7 +212,8 @@ struct mca_btl_base_descriptor_t* mca_btl_self_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_self_frag_t* frag;
     struct iovec iov;
@@ -279,7 +281,8 @@ struct mca_btl_base_descriptor_t* mca_btl_self_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_self_frag_t* frag;
     size_t max_data = *size;
diff --git a/ompi/mca/btl/self/btl_self.h b/ompi/mca/btl/self/btl_self.h
index 1a1d191d89..1c4d13434f 100644
--- a/ompi/mca/btl/self/btl_self.h
+++ b/ompi/mca/btl/self/btl_self.h
@@ -165,7 +165,8 @@ mca_btl_base_descriptor_t* mca_btl_self_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size
+    size_t size,
+    uint32_t flags
 );
 
 /**
@@ -192,7 +193,8 @@ struct mca_btl_base_descriptor_t* mca_btl_self_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
                                                                                                             
 /**
@@ -208,7 +210,8 @@ struct mca_btl_base_descriptor_t* mca_btl_self_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
                                                                                                             
 /**
diff --git a/ompi/mca/btl/sm/btl_sm.c b/ompi/mca/btl/sm/btl_sm.c
index 9db917b10d..d5b0f6ae29 100644
--- a/ompi/mca/btl/sm/btl_sm.c
+++ b/ompi/mca/btl/sm/btl_sm.c
@@ -721,7 +721,8 @@ extern mca_btl_base_descriptor_t* mca_btl_sm_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_sm_frag_t* frag;
     int rc;
@@ -769,7 +770,8 @@ struct mca_btl_base_descriptor_t* mca_btl_sm_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_sm_frag_t* frag;
     struct iovec iov;
diff --git a/ompi/mca/btl/sm/btl_sm.h b/ompi/mca/btl/sm/btl_sm.h
index d0fd5e16bf..60cba9c536 100644
--- a/ompi/mca/btl/sm/btl_sm.h
+++ b/ompi/mca/btl/sm/btl_sm.h
@@ -280,7 +280,8 @@ extern mca_btl_base_descriptor_t* mca_btl_sm_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size
+    size_t size,
+    uint32_t flags
 );
 
 /**
@@ -308,7 +309,8 @@ struct mca_btl_base_descriptor_t* mca_btl_sm_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 
diff --git a/ompi/mca/btl/tcp/btl_tcp.c b/ompi/mca/btl/tcp/btl_tcp.c
index 68f1f13b76..c1472717e7 100644
--- a/ompi/mca/btl/tcp/btl_tcp.c
+++ b/ompi/mca/btl/tcp/btl_tcp.c
@@ -188,7 +188,8 @@ mca_btl_base_descriptor_t* mca_btl_tcp_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_tcp_frag_t* frag;
     int rc;
@@ -243,7 +244,8 @@ mca_btl_base_descriptor_t* mca_btl_tcp_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_tcp_frag_t* frag;
     struct iovec iov;
@@ -338,7 +340,8 @@ mca_btl_base_descriptor_t* mca_btl_tcp_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_tcp_frag_t* frag;
     int rc;
diff --git a/ompi/mca/btl/tcp/btl_tcp.h b/ompi/mca/btl/tcp/btl_tcp.h
index 420dca34b6..7954ec057b 100644
--- a/ompi/mca/btl/tcp/btl_tcp.h
+++ b/ompi/mca/btl/tcp/btl_tcp.h
@@ -296,7 +296,8 @@ extern mca_btl_base_descriptor_t* mca_btl_tcp_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size); 
+    size_t size,
+    uint32_t flags); 
 
 
 /**
@@ -332,7 +333,8 @@ mca_btl_base_descriptor_t* mca_btl_tcp_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 extern mca_btl_base_descriptor_t* mca_btl_tcp_prepare_dst( 
@@ -342,7 +344,8 @@ extern mca_btl_base_descriptor_t* mca_btl_tcp_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size); 
+    size_t* size,
+    uint32_t flags); 
 
 
 /**
diff --git a/ompi/mca/btl/template/btl_template.c b/ompi/mca/btl/template/btl_template.c
index ad7de7ac4b..85bbcf432b 100644
--- a/ompi/mca/btl/template/btl_template.c
+++ b/ompi/mca/btl/template/btl_template.c
@@ -167,7 +167,8 @@ mca_btl_base_descriptor_t* mca_btl_template_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_template_module_t* template_btl = (mca_btl_template_module_t*) btl; 
     mca_btl_template_frag_t* frag;
@@ -228,7 +229,8 @@ mca_btl_base_descriptor_t* mca_btl_template_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 )
 {
     mca_btl_template_frag_t* frag;
@@ -317,7 +319,8 @@ mca_btl_base_descriptor_t* mca_btl_template_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_template_frag_t* frag;
     int rc;
diff --git a/ompi/mca/btl/template/btl_template.h b/ompi/mca/btl/template/btl_template.h
index 0aef963d55..437bc04927 100644
--- a/ompi/mca/btl/template/btl_template.h
+++ b/ompi/mca/btl/template/btl_template.h
@@ -260,7 +260,8 @@ extern mca_btl_base_descriptor_t* mca_btl_template_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size); 
+    size_t size,
+    uint32_t flags); 
 
 
 /**
@@ -296,7 +297,8 @@ mca_btl_base_descriptor_t* mca_btl_template_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 extern mca_btl_base_descriptor_t* mca_btl_template_prepare_dst( 
@@ -306,7 +308,8 @@ extern mca_btl_base_descriptor_t* mca_btl_template_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size); 
+    size_t* size,
+    uint32_t flags); 
 
  /**
   * Fault Tolerance Event Notification Function
diff --git a/ompi/mca/btl/udapl/btl_udapl.c b/ompi/mca/btl/udapl/btl_udapl.c
index cbd0c4f7f3..4ef7419210 100644
--- a/ompi/mca/btl/udapl/btl_udapl.c
+++ b/ompi/mca/btl/udapl/btl_udapl.c
@@ -737,7 +737,8 @@ mca_btl_base_descriptor_t* mca_btl_udapl_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size)
+    size_t size,
+    uint32_t flags)
 {
     mca_btl_udapl_module_t* udapl_btl = (mca_btl_udapl_module_t*) btl; 
     mca_btl_udapl_frag_t* frag;
@@ -823,7 +824,8 @@ mca_btl_base_descriptor_t* mca_btl_udapl_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 )
 {
     mca_btl_udapl_frag_t* frag = NULL;
@@ -951,7 +953,8 @@ mca_btl_base_descriptor_t* mca_btl_udapl_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size)
+    size_t* size,
+    uint32_t flags)
 {
     mca_btl_udapl_frag_t* frag;
     int rc;
diff --git a/ompi/mca/btl/udapl/btl_udapl.h b/ompi/mca/btl/udapl/btl_udapl.h
index 5e699b380c..40ca7f12cc 100644
--- a/ompi/mca/btl/udapl/btl_udapl.h
+++ b/ompi/mca/btl/udapl/btl_udapl.h
@@ -345,7 +345,8 @@ extern mca_btl_base_descriptor_t* mca_btl_udapl_alloc(
     struct mca_btl_base_module_t* btl,
     struct mca_btl_base_endpoint_t* endpoint,
     uint8_t order,
-    size_t size); 
+    size_t size,
+    uint32_t flags); 
 
 
 /**
@@ -381,7 +382,8 @@ mca_btl_base_descriptor_t* mca_btl_udapl_prepare_src(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size
+    size_t* size,
+    uint32_t flags
 );
 
 extern mca_btl_base_descriptor_t* mca_btl_udapl_prepare_dst( 
@@ -391,7 +393,8 @@ extern mca_btl_base_descriptor_t* mca_btl_udapl_prepare_dst(
     struct ompi_convertor_t* convertor,
     uint8_t order,
     size_t reserve,
-    size_t* size); 
+    size_t* size,
+    uint32_t flags); 
 
     /**
      * Fault Tolerance Event Notification Function
diff --git a/ompi/mca/osc/rdma/osc_rdma_component.c b/ompi/mca/osc/rdma/osc_rdma_component.c
index 302dd9e99f..62e02ed9de 100644
--- a/ompi/mca/osc/rdma/osc_rdma_component.c
+++ b/ompi/mca/osc/rdma/osc_rdma_component.c
@@ -1045,7 +1045,8 @@ rdma_send_info_send(ompi_osc_rdma_module_t *module,
         
     bml_btl = peer_send_info->bml_btl;
     mca_bml_base_alloc(bml_btl, &descriptor, MCA_BTL_NO_ORDER,
-            sizeof(ompi_osc_rdma_rdma_info_header_t));
+            sizeof(ompi_osc_rdma_rdma_info_header_t),
+            MCA_BTL_DES_FLAGS_PRIORITY);
     if (NULL == descriptor) {
         ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE;
         goto cleanup;
@@ -1241,14 +1242,11 @@ setup_rdma(ompi_osc_rdma_module_t *module)
                                                      0,
                                                      &convertor);
 
-            peer_info->local_descriptors[index] = 
-                bml_btl->btl_prepare_dst(bml_btl->btl,
-                                         bml_btl->btl_endpoint,
-                                         peer_info->local_registrations[index],
-                                         &convertor,
-                                         MCA_BTL_NO_ORDER,
-                                         0,
-                                         &size);
+            mca_bml_base_prepare_dst(bml_btl,
+                    peer_info->local_registrations[index],
+                    &convertor, MCA_BTL_NO_ORDER, 0, &size, 0,
+                    &peer_info->local_descriptors[index]);
+
             if (NULL == peer_info->local_descriptors[index]) {
                 if (NULL != peer_info->local_registrations[index]) {
                     btl_mpool->mpool_deregister(btl_mpool,
diff --git a/ompi/mca/osc/rdma/osc_rdma_data_move.c b/ompi/mca/osc/rdma/osc_rdma_data_move.c
index e7b581349d..42a43b4588 100644
--- a/ompi/mca/osc/rdma/osc_rdma_data_move.c
+++ b/ompi/mca/osc/rdma/osc_rdma_data_move.c
@@ -173,14 +173,9 @@ ompi_osc_rdma_sendreq_rdma(ompi_osc_rdma_module_t *module,
         rdma_btl = &(module->m_peer_info[target].peer_btls[index]);
 
         if (sendreq->req_type == OMPI_OSC_RDMA_PUT) {
-            descriptor = rdma_btl->bml_btl->
-                btl_prepare_src(rdma_btl->bml_btl->btl,
-                                rdma_btl->bml_btl->btl_endpoint,
-                                NULL, /* BWB - fix me */
-                                &sendreq->req_origin_convertor,
-                                rdma_btl->rdma_order,
-                                0,
-                                &size);
+            mca_bml_base_prepare_src(rdma_btl->bml_btl, NULL,
+                    &sendreq->req_origin_convertor, rdma_btl->rdma_order,
+                    0, &size, 0, &descriptor);
 
             assert(NULL != descriptor);
 
@@ -208,14 +203,9 @@ ompi_osc_rdma_sendreq_rdma(ompi_osc_rdma_module_t *module,
                         rdma_btl->bml_btl->btl_endpoint,
                         descriptor);
         } else {
-            descriptor = rdma_btl->bml_btl->
-                btl_prepare_dst(rdma_btl->bml_btl->btl,
-                                rdma_btl->bml_btl->btl_endpoint,
-                                NULL, /* BWB - fix me */
-                                &sendreq->req_origin_convertor,
-                                rdma_btl->rdma_order,
-                                0,
-                                &size);
+            mca_bml_base_prepare_dst(rdma_btl->bml_btl,
+                    NULL, &sendreq->req_origin_convertor, rdma_btl->rdma_order,
+                    0, &size, 0, &descriptor);
 
             assert(NULL != descriptor);
 
@@ -457,7 +447,7 @@ ompi_osc_rdma_sendreq_send(ompi_osc_rdma_module_t *module,
         mca_bml_base_alloc(bml_btl, &descriptor, MCA_BTL_NO_ORDER,
                 module->m_use_buffers ? bml_btl->btl_eager_limit :
                 needed_len < bml_btl->btl_eager_limit ? needed_len :
-                bml_btl->btl_eager_limit);
+                bml_btl->btl_eager_limit, MCA_BTL_DES_FLAGS_PRIORITY);
         if (NULL == descriptor) {
             ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE;
             goto cleanup;
@@ -699,7 +689,7 @@ ompi_osc_rdma_replyreq_send(ompi_osc_rdma_module_t *module,
     endpoint = (mca_bml_base_endpoint_t*) replyreq->rep_origin_proc->proc_bml;
     bml_btl = mca_bml_base_btl_array_get_next(&endpoint->btl_eager);
     mca_bml_base_alloc(bml_btl, &descriptor, MCA_BTL_NO_ORDER,
-            bml_btl->btl_eager_limit);
+            bml_btl->btl_eager_limit, MCA_BTL_DES_FLAGS_PRIORITY);
     if (NULL == descriptor) {
         ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE;
         goto cleanup;
@@ -1260,7 +1250,8 @@ ompi_osc_rdma_control_send(ompi_osc_rdma_module_t *module,
     endpoint = (mca_bml_base_endpoint_t*) proc->proc_bml;
     bml_btl = mca_bml_base_btl_array_get_next(&endpoint->btl_eager);
     mca_bml_base_alloc(bml_btl, &descriptor, MCA_BTL_NO_ORDER,
-            sizeof(ompi_osc_rdma_control_header_t));
+            sizeof(ompi_osc_rdma_control_header_t),
+            MCA_BTL_DES_FLAGS_PRIORITY);
     if (NULL == descriptor) {
         ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE;
         goto cleanup;
@@ -1321,7 +1312,8 @@ ompi_osc_rdma_rdma_ack_send(ompi_osc_rdma_module_t *module,
         
     /* Get a BTL and a fragment to go with it */
     mca_bml_base_alloc(bml_btl, &descriptor, rdma_btl->rdma_order,
-            sizeof(ompi_osc_rdma_control_header_t));
+            sizeof(ompi_osc_rdma_control_header_t),
+            MCA_BTL_DES_FLAGS_PRIORITY);
     if (NULL == descriptor) {
         ret = OMPI_ERR_TEMP_OUT_OF_RESOURCE;
         goto cleanup;
diff --git a/ompi/mca/pml/dr/pml_dr_recvfrag.c b/ompi/mca/pml/dr/pml_dr_recvfrag.c
index b8d4ec43f7..d74a4613ec 100644
--- a/ompi/mca/pml/dr/pml_dr_recvfrag.c
+++ b/ompi/mca/pml/dr/pml_dr_recvfrag.c
@@ -803,7 +803,7 @@ void mca_pml_dr_recv_frag_ack(
 
     /* allocate descriptor */
     mca_bml_base_alloc(bml_btl, &des, MCA_BTL_NO_ORDER,
-            sizeof(mca_pml_dr_ack_hdr_t));
+            sizeof(mca_pml_dr_ack_hdr_t), MCA_BTL_DES_FLAGS_PRIORITY);
     if(NULL == des) {
         goto retry;
     }
diff --git a/ompi/mca/pml/dr/pml_dr_recvreq.c b/ompi/mca/pml/dr/pml_dr_recvreq.c
index d64ef21930..51e22ee659 100644
--- a/ompi/mca/pml/dr/pml_dr_recvreq.c
+++ b/ompi/mca/pml/dr/pml_dr_recvreq.c
@@ -184,7 +184,7 @@ void mca_pml_dr_recv_request_ack(
     do_csum = mca_pml_dr.enable_csum && 
         (bml_btl->btl_flags & MCA_BTL_FLAGS_NEED_CSUM);
     mca_bml_base_alloc(bml_btl, &des, MCA_BTL_NO_ORDER,
-            sizeof(mca_pml_dr_ack_hdr_t));
+            sizeof(mca_pml_dr_ack_hdr_t), MCA_BTL_DES_FLAGS_PRIORITY);
     if(NULL == des) {
         return;
     }
diff --git a/ompi/mca/pml/dr/pml_dr_sendreq.c b/ompi/mca/pml/dr/pml_dr_sendreq.c
index cb6c024416..1167fcd591 100644
--- a/ompi/mca/pml/dr/pml_dr_sendreq.c
+++ b/ompi/mca/pml/dr/pml_dr_sendreq.c
@@ -384,7 +384,8 @@ int mca_pml_dr_send_request_start_buffered(
     
     /* allocate descriptor */
     mca_bml_base_alloc(bml_btl, &descriptor, MCA_BTL_NO_ORDER,
-                       sizeof(mca_pml_dr_rendezvous_hdr_t) + size);
+                       sizeof(mca_pml_dr_rendezvous_hdr_t) + size,
+                       MCA_BTL_DES_FLAGS_PRIORITY);
     if(NULL == descriptor) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     } 
@@ -498,7 +499,8 @@ int mca_pml_dr_send_request_start_copy(
     /* allocate descriptor */
     mca_bml_base_alloc(bml_btl, &descriptor, 
                        MCA_BTL_NO_ORDER,
-                       sizeof(mca_pml_dr_match_hdr_t) + size);
+                       sizeof(mca_pml_dr_match_hdr_t) + size,
+                       MCA_BTL_DES_FLAGS_PRIORITY);
     if(NULL == descriptor) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     }
@@ -587,7 +589,8 @@ int mca_pml_dr_send_request_start_prepare(
                               MCA_BTL_NO_ORDER,
                               sizeof(mca_pml_dr_match_hdr_t),
                               &size,
-                              &descriptor);
+                              MCA_BTL_DES_FLAGS_PRIORITY,
+                              &descriptor );
     if(NULL == descriptor) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     } 
@@ -656,7 +659,8 @@ int mca_pml_dr_send_request_start_rndv(
         mca_bml_base_alloc( bml_btl, 
                             &des, 
                             MCA_BTL_NO_ORDER,
-                            sizeof(mca_pml_dr_rendezvous_hdr_t) ); 
+                            sizeof(mca_pml_dr_rendezvous_hdr_t),
+                            MCA_BTL_DES_FLAGS_PRIORITY ); 
     } else {
         mca_bml_base_prepare_src( bml_btl, 
                                   NULL,
@@ -664,7 +668,8 @@ int mca_pml_dr_send_request_start_rndv(
                                   MCA_BTL_NO_ORDER,
                                   sizeof(mca_pml_dr_rendezvous_hdr_t),
                                   &size,
-                                  &des);
+                                  MCA_BTL_DES_FLAGS_PRIORITY,
+                                  &des );
     }
 
     if(NULL == des) {
@@ -775,6 +780,7 @@ int mca_pml_dr_send_request_schedule(mca_pml_dr_send_request_t* sendreq)
                                                  MCA_BTL_NO_ORDER,
                                                  sizeof(mca_pml_dr_frag_hdr_t),
                                                  &size,
+                                                 0,
                                                  &des );
                         if(des == NULL) {
                             OPAL_THREAD_LOCK(&ompi_request_lock);
@@ -898,6 +904,7 @@ int mca_pml_dr_send_request_schedule(mca_pml_dr_send_request_t* sendreq)
                                           MCA_BTL_NO_ORDER,
                                           sizeof(mca_pml_dr_frag_hdr_t),
                                           &size,
+                                          0,
                                           &des );
                 if(des == NULL) {
                     OPAL_THREAD_LOCK(&mca_pml_dr.lock);
diff --git a/ompi/mca/pml/dr/pml_dr_sendreq.h b/ompi/mca/pml/dr/pml_dr_sendreq.h
index ce00daff78..0e49adad1b 100644
--- a/ompi/mca/pml/dr/pml_dr_sendreq.h
+++ b/ompi/mca/pml/dr/pml_dr_sendreq.h
@@ -375,7 +375,8 @@ do {                                                                  \
                                                                         \
         des_old = sendreq->req_descriptor;                              \
         mca_bml_base_alloc(vfrag->bml_btl, &des_new,                    \
-                           MCA_BTL_NO_ORDER, des_old->des_src->seg_len); \
+                           MCA_BTL_NO_ORDER, des_old->des_src->seg_len, \
+                           des_old->des_flags);                         \
         sendreq->req_descriptor = des_new;                              \
         memcpy(des_new->des_src->seg_addr.pval,                         \
                des_old->des_src->seg_addr.pval,                         \
@@ -408,7 +409,8 @@ do {                                                                 \
     assert(sendreq->req_descriptor->des_src != NULL);                \
     mca_bml_base_alloc(bml_btl, &des_new,                            \
                        MCA_BTL_NO_ORDER,                             \
-                       sizeof(mca_pml_dr_rendezvous_hdr_t));         \
+                       sizeof(mca_pml_dr_rendezvous_hdr_t),          \
+                       des_old->des_flags);                          \
     des_old = sendreq->req_descriptor;                               \
     /* build hdr */                                                  \
     hdr = (mca_pml_dr_hdr_t*)des_new->des_src->seg_addr.pval;        \
diff --git a/ompi/mca/pml/ob1/pml_ob1.c b/ompi/mca/pml/ob1/pml_ob1.c
index bf102be099..b846abc208 100644
--- a/ompi/mca/pml/ob1/pml_ob1.c
+++ b/ompi/mca/pml/ob1/pml_ob1.c
@@ -330,7 +330,8 @@ int mca_pml_ob1_send_fin( ompi_proc_t* proc,
     mca_pml_ob1_fin_hdr_t* hdr;
     int rc;
 
-    mca_bml_base_alloc(bml_btl, &fin, order, sizeof(mca_pml_ob1_fin_hdr_t));
+    mca_bml_base_alloc(bml_btl, &fin, order, sizeof(mca_pml_ob1_fin_hdr_t),
+            MCA_BTL_DES_FLAGS_PRIORITY);
 
     if(NULL == fin) {
         MCA_PML_OB1_ADD_FIN_TO_PENDING(proc, hdr_des, bml_btl, order, status);
diff --git a/ompi/mca/pml/ob1/pml_ob1_recvreq.c b/ompi/mca/pml/ob1/pml_ob1_recvreq.c
index 26ed2c4809..e8818348c4 100644
--- a/ompi/mca/pml/ob1/pml_ob1_recvreq.c
+++ b/ompi/mca/pml/ob1/pml_ob1_recvreq.c
@@ -190,7 +190,7 @@ int mca_pml_ob1_recv_request_ack_send_btl(
 
     /* allocate descriptor */
     mca_bml_base_alloc(bml_btl, &des, MCA_BTL_NO_ORDER,
-                sizeof(mca_pml_ob1_ack_hdr_t));
+                sizeof(mca_pml_ob1_ack_hdr_t), MCA_BTL_DES_FLAGS_PRIORITY);
     if( OPAL_UNLIKELY(NULL == des) ) {
         return OMPI_ERR_OUT_OF_RESOURCE; 
     }
@@ -352,7 +352,8 @@ int mca_pml_ob1_recv_request_get_frag( mca_pml_ob1_rdma_frag_t* frag )
                               &recvreq->req_recv.req_base.req_convertor,
                               MCA_BTL_NO_ORDER,
                               0,
-                              &frag->rdma_length, 
+                              &frag->rdma_length,
+                              0,
                               &descriptor );
     if( OPAL_UNLIKELY(NULL == descriptor) ) {
         frag->rdma_length = save_size;
@@ -658,7 +659,7 @@ int mca_pml_ob1_recv_request_schedule_once(
         /* prepare a descriptor for RDMA */
         mca_bml_base_prepare_dst(bml_btl, reg, 
                                  &recvreq->req_recv.req_base.req_convertor,
-                                 MCA_BTL_NO_ORDER, 0, &size, &dst);
+                                 MCA_BTL_NO_ORDER, 0, &size, 0, &dst);
         OPAL_THREAD_UNLOCK(&recvreq->lock);
 
         if(OPAL_UNLIKELY(dst == NULL)) {
@@ -675,7 +676,8 @@ int mca_pml_ob1_recv_request_schedule_once(
                     (dst->des_dst_cnt-1));
         }
 
-        mca_bml_base_alloc(bml_btl, &ctl, MCA_BTL_NO_ORDER, hdr_size);
+        mca_bml_base_alloc(bml_btl, &ctl, MCA_BTL_NO_ORDER, hdr_size,
+                MCA_BTL_DES_FLAGS_PRIORITY);
 
         if( OPAL_UNLIKELY(NULL == ctl) ) {
             mca_bml_base_free(bml_btl,dst);
diff --git a/ompi/mca/pml/ob1/pml_ob1_sendreq.c b/ompi/mca/pml/ob1/pml_ob1_sendreq.c
index c2fa92c2a8..5b11bfd406 100644
--- a/ompi/mca/pml/ob1/pml_ob1_sendreq.c
+++ b/ompi/mca/pml/ob1/pml_ob1_sendreq.c
@@ -328,7 +328,9 @@ int mca_pml_ob1_send_request_start_buffered(
 
     /* allocate descriptor */
     mca_bml_base_alloc(bml_btl, &descriptor, 
-                       MCA_BTL_NO_ORDER, sizeof(mca_pml_ob1_rendezvous_hdr_t) + size);
+                       MCA_BTL_NO_ORDER,
+                       sizeof(mca_pml_ob1_rendezvous_hdr_t) + size,
+                       MCA_BTL_DES_FLAGS_PRIORITY);
     if( OPAL_UNLIKELY(NULL == descriptor) ) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     } 
@@ -442,7 +444,8 @@ int mca_pml_ob1_send_request_start_copy( mca_pml_ob1_send_request_t* sendreq,
     /* allocate descriptor */
     mca_bml_base_alloc( bml_btl, &descriptor,
                         MCA_BTL_NO_ORDER,
-                        sizeof(mca_pml_ob1_match_hdr_t) + size );
+                        sizeof(mca_pml_ob1_match_hdr_t) + size,
+                        MCA_BTL_DES_FLAGS_PRIORITY);
     if( OPAL_UNLIKELY(NULL == descriptor) ) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     }
@@ -522,7 +525,8 @@ int mca_pml_ob1_send_request_start_prepare( mca_pml_ob1_send_request_t* sendreq,
                               MCA_BTL_NO_ORDER,
                               sizeof(mca_pml_ob1_match_hdr_t),
                               &size,
-                              &descriptor);
+                              MCA_BTL_DES_FLAGS_PRIORITY,
+                              &descriptor );
     if( OPAL_UNLIKELY(NULL == descriptor) ) {
         return OMPI_ERR_OUT_OF_RESOURCE;
     }
@@ -604,6 +608,7 @@ int mca_pml_ob1_send_request_start_rdma(
                                   MCA_BTL_NO_ORDER,
                                   0,
                                   &size,
+                                  0,
                                   &src );
         if( OPAL_UNLIKELY(NULL == src) ) {
             ompi_convertor_set_position(&sendreq->req_send.req_base.req_convertor,
@@ -615,10 +620,13 @@ int mca_pml_ob1_send_request_start_rdma(
 
         /* allocate space for get hdr + segment list */
         mca_bml_base_alloc(bml_btl, &des, MCA_BTL_NO_ORDER,
-                           sizeof(mca_pml_ob1_rget_hdr_t) + (sizeof(mca_btl_base_segment_t)*(src->des_src_cnt-1)));
+                sizeof(mca_pml_ob1_rget_hdr_t) +
+                (sizeof(mca_btl_base_segment_t) * (src->des_src_cnt-1)),
+                MCA_BTL_DES_FLAGS_PRIORITY);
         if( OPAL_UNLIKELY(NULL == des) ) {
-            ompi_convertor_set_position(&sendreq->req_send.req_base.req_convertor,
-                                        &old_position);
+            ompi_convertor_set_position(
+                    &sendreq->req_send.req_base.req_convertor,
+                    &old_position);
             mca_bml_base_free(bml_btl, src);
             return OMPI_ERR_OUT_OF_RESOURCE;
         }
@@ -676,7 +684,9 @@ int mca_pml_ob1_send_request_start_rdma(
          */
 
         mca_bml_base_alloc(bml_btl, &des, 
-                           MCA_BTL_NO_ORDER, sizeof(mca_pml_ob1_rendezvous_hdr_t));
+                           MCA_BTL_NO_ORDER,
+                           sizeof(mca_pml_ob1_rendezvous_hdr_t),
+                           MCA_BTL_DES_FLAGS_PRIORITY);
         if( OPAL_UNLIKELY(NULL == des)) {
             return OMPI_ERR_OUT_OF_RESOURCE;
         }
@@ -749,7 +759,8 @@ int mca_pml_ob1_send_request_start_rndv( mca_pml_ob1_send_request_t* sendreq,
         mca_bml_base_alloc( bml_btl, 
                             &des, 
                             MCA_BTL_NO_ORDER,
-                            sizeof(mca_pml_ob1_rendezvous_hdr_t) ); 
+                            sizeof(mca_pml_ob1_rendezvous_hdr_t),
+                            MCA_BTL_DES_FLAGS_PRIORITY ); 
     } else {
         mca_bml_base_prepare_src( bml_btl, 
                                   NULL,
@@ -757,6 +768,7 @@ int mca_pml_ob1_send_request_start_rndv( mca_pml_ob1_send_request_t* sendreq,
                                   MCA_BTL_NO_ORDER,
                                   sizeof(mca_pml_ob1_rendezvous_hdr_t),
                                   &size,
+                                  MCA_BTL_DES_FLAGS_PRIORITY,
                                   &des );
     }
 
@@ -964,7 +976,8 @@ cannot_pack:
         mca_bml_base_prepare_src(bml_btl, NULL,
                                  &sendreq->req_send.req_base.req_convertor,
                                  MCA_BTL_NO_ORDER,
-                                 sizeof(mca_pml_ob1_frag_hdr_t), &size, &des);
+                                 sizeof(mca_pml_ob1_frag_hdr_t),
+                                 &size, 0, &des);
 
         if( OPAL_UNLIKELY(des == NULL || size == 0) ) {
             if(des) {
@@ -1091,7 +1104,8 @@ int mca_pml_ob1_send_request_put_frag( mca_pml_ob1_rdma_frag_t* frag )
                               &frag->convertor, 
                               MCA_BTL_NO_ORDER,
                               0,
-                              &frag->rdma_length, 
+                              &frag->rdma_length,
+                              0,
                               &des );
     
     if( OPAL_UNLIKELY(NULL == des) ) {