diff --git a/ompi/mca/mpool/base/base.h b/ompi/mca/mpool/base/base.h
index 75d782dcb1..9e9df155ac 100644
--- a/ompi/mca/mpool/base/base.h
+++ b/ompi/mca/mpool/base/base.h
@@ -46,54 +46,6 @@ OBJ_CLASS_DECLARATION(mca_mpool_base_selected_module_t);
  * Data structures for the tree of allocated memory
  */
 
-/**
- * The maximum number of mpools a chunk of memorry can be registered with
- */
-#define MCA_MPOOL_BASE_MAX_REG 8
-
-/**
- * Holds the key for the tree
- */
-struct mca_mpool_base_key_t
-{
-    void * bottom;          /**< the bottom of the memory range */
-    void * top;             /**< the top of the memory range */
-};
-typedef struct mca_mpool_base_key_t mca_mpool_base_key_t;
-
-/**
- * Holds a pointer to the mpool the memory is registered with and 
- * a user pointer for mpool specific information
- */
-struct mca_mpool_base_reg_mpool_t
-{
-    mca_mpool_base_module_t * mpool; /**< the registered memory pool */
-    void* user_data; /**< user data */
-    mca_mpool_base_registration_t* mpool_registration; /**< mpool specific info associated w/ registration */
-};
-typedef struct mca_mpool_base_reg_mpool_t mca_mpool_base_reg_mpool_t;
-
-/**
- * Holds all the information about a chunk of registered memory. The whole
- * structure serves as a value in the tree
- */
-struct mca_mpool_base_chunk_t
-{
-    opal_list_item_t super;   /**< the parent class */
-    mca_mpool_base_key_t key; /**< the key which holds the memory pointers */
-    mca_mpool_base_reg_mpool_t mpools[MCA_MPOOL_BASE_MAX_REG]; 
-                              /**< the mpools the memory is registered with */
-};
-typedef struct mca_mpool_base_chunk_t mca_mpool_base_chunk_t;
-
-OBJ_CLASS_DECLARATION(mca_mpool_base_chunk_t);
-
-
-/**
- *  Returns a copy of the chunk.
- */
-mca_mpool_base_chunk_t* mca_mpool_base_find(void* base);
-
 /*
  * Global functions for MCA: overall mpool open and close
  */
@@ -115,9 +67,6 @@ OMPI_DECLSPEC int mca_mpool_base_module_destroy(mca_mpool_base_module_t *module)
 OMPI_DECLSPEC extern int mca_mpool_base_output;
 OMPI_DECLSPEC extern opal_list_t mca_mpool_base_components;
 OMPI_DECLSPEC extern opal_list_t mca_mpool_base_modules;
-OMPI_DECLSPEC extern ompi_free_list_t mca_mpool_base_mem_list;
-OMPI_DECLSPEC extern ompi_rb_tree_t mca_mpool_base_tree;
-OMPI_DECLSPEC extern opal_mutex_t mca_mpool_base_tree_lock; 
 
 #if defined(c_plusplus) || defined(__cplusplus)
 }
diff --git a/ompi/mca/mpool/base/mpool_base_alloc.c b/ompi/mca/mpool/base/mpool_base_alloc.c
index 3627fe050f..39afad21d1 100644
--- a/ompi/mca/mpool/base/mpool_base_alloc.c
+++ b/ompi/mca/mpool/base/mpool_base_alloc.c
@@ -25,60 +25,6 @@
 #include "mca/mpool/base/base.h"
 #include "opal/threads/mutex.h" 
 
-ompi_rb_tree_t mca_mpool_base_tree;
-ompi_free_list_t mca_mpool_base_mem_list;
-opal_mutex_t mca_mpool_base_tree_lock; 
-
-
-/**
- * Searches the mpool to see if it has allocated the memory that is passed in.
- * If so it returns an array of mpools the memory is registered with.
- *
- * @param base pointer to the memory to lookup
- *
- * @retval NULL if the memory is not in any mpool
- * @retval pointer to an array of type mca_mpool_base_reg_mpool_t
- */
-static inline struct mca_mpool_base_chunk_t * mca_mpool_base_find_nl(void * base)
-{
-    mca_mpool_base_key_t key;
-    key.bottom = base;
-    key.top = base;
-    return (mca_mpool_base_chunk_t *)ompi_rb_tree_find(&mca_mpool_base_tree, &key);
-}
-
-/**
- * Searches the mpool to see if it has allocated the memory that is passed in.
- * If so it returns an array of mpools the memory is registered with.
- *
- * @param base pointer to the memory to lookup
- *
- * @retval NULL if the memory is not in any mpool
- * @retval pointer to an array of type mca_mpool_base_reg_mpool_t
- */
-struct mca_mpool_base_chunk_t * mca_mpool_base_find(void * base)
-{
-    mca_mpool_base_chunk_t* found;
-    mca_mpool_base_chunk_t* copy;
-
-    OPAL_THREAD_LOCK(&mca_mpool_base_tree_lock);
-    if(NULL != (found = mca_mpool_base_find_nl(base))) {
-        mca_mpool_base_reg_mpool_t* reg;
-        copy = OBJ_NEW(mca_mpool_base_chunk_t);
-        *copy = *found;
-        reg = copy->mpools;
-        while(NULL != reg->mpool) {
-            if(NULL != reg->mpool_registration)
-                OBJ_RETAIN(reg->mpool_registration);
-            reg++;
-        }
-    } else {
-        copy = NULL;
-    }
-    OPAL_THREAD_UNLOCK(&mca_mpool_base_tree_lock);
-    return copy;
-}
-
 /**
  * Memory Pool Registration
  */
@@ -102,88 +48,6 @@ OBJ_CLASS_INSTANCE(
     mca_mpool_base_registration_constructor,
     mca_mpool_base_registration_destructor);
 
-/**
- * Function for the red black tree to compare 2 keys
- *
- * @param key1 a pointer to the 1st key
- * @param key2 a pointer to the second key
- *
- * @retval -1 if key1 is below key2
- * @retval 1 if key 1 is above key2
- * @retval 0 if the keys are the same
- */
-int mca_mpool_base_tree_node_compare(void * key1, void * key2)
-{
-    if(((mca_mpool_base_key_t *) key1)->bottom <
-       ((mca_mpool_base_key_t *) key2)->bottom)
-    {
-        return -1;
-    }
-    else if(((mca_mpool_base_key_t *) key1)->bottom >
-            ((mca_mpool_base_key_t *) key2)->top)
-    {
-        return 1;
-    }
-    else
-    {
-        return 0;
-    }
-}
-
-int mca_mpool_base_insert(void * addr, size_t size, 
-                          mca_mpool_base_module_t* mpool, 
-                          void* user_data,
-                          mca_mpool_base_registration_t* registration)
-{
-    opal_list_item_t *item; 
-    int rc; 
-    OMPI_FREE_LIST_GET(&mca_mpool_base_mem_list, item, rc);
-    if(rc != OMPI_SUCCESS) 
-        return rc; 
-    memset( ((mca_mpool_base_chunk_t *) item)->mpools, 0, sizeof(mca_mpool_base_reg_mpool_t) * MCA_MPOOL_BASE_MAX_REG); 
-    
-    ((mca_mpool_base_chunk_t *) item)->key.bottom = addr;
-    ((mca_mpool_base_chunk_t *) item)->key.top = (void *) 
-        ((char *) addr + size - 1);
-    ((mca_mpool_base_chunk_t *) item)->mpools[0].mpool = mpool; 
-    ((mca_mpool_base_chunk_t *) item)->mpools[0].user_data = user_data;
-    ((mca_mpool_base_chunk_t *) item)->mpools[0].mpool_registration = registration;
-    
-    
-    OPAL_THREAD_LOCK(&mca_mpool_base_tree_lock); 
-    rc = ompi_rb_tree_insert(&mca_mpool_base_tree, 
-                        &((mca_mpool_base_chunk_t *)item)->key, item);
-    OPAL_THREAD_UNLOCK(&mca_mpool_base_tree_lock); 
-    if(OMPI_SUCCESS != rc) {
-        OMPI_FREE_LIST_RETURN(&mca_mpool_base_mem_list, item);
-        return rc; 
-    }
-    return OMPI_SUCCESS; 
-}
-
-/**
- * Function to remove previously memory from the tree without freeing it
- *
- * @param base pointer to the memory to free
- *
- * @retval OMPI_SUCCESS
- * @retval OMPI_ERR_BAD_PARAM if the passed base pointer was invalid
- */
-int mca_mpool_base_remove(void * base)
-{
-    int rc; 
-    mca_mpool_base_chunk_t *chunk;
-
-    OPAL_THREAD_LOCK(&mca_mpool_base_tree_lock); 
-    if(NULL == (chunk = mca_mpool_base_find_nl(base))) {
-        OPAL_THREAD_UNLOCK(&mca_mpool_base_tree_lock); 
-        return OMPI_ERR_BAD_PARAM;
-    }
-    rc =  ompi_rb_tree_delete(&mca_mpool_base_tree, &chunk->key); 
-    OPAL_THREAD_UNLOCK(&mca_mpool_base_tree_lock);
-    return rc;
-}
-
 /**
  * Function to allocate special memory according to what the user requests in
  * the info object.
@@ -225,11 +89,13 @@ void * mca_mpool_base_alloc(size_t size, ompi_info_t * info)
             item != opal_list_get_end(&mca_mpool_base_modules);
             item = opal_list_get_next(item)) {
             current = ((mca_mpool_base_selected_module_t *) item);
-            if(NULL == current->mpool_module->mpool_register){
-                no_reg_function = current;
-            }
-            else {
-                has_reg_function[reg_module_num++] = current;
+            if(current->mpool_module->flags & MCA_MPOOL_FLAGS_MPI_ALLOC_MEM) {
+                if(NULL == current->mpool_module->mpool_register){
+                    no_reg_function = current;
+                }
+                else {
+                    has_reg_function[reg_module_num++] = current;
+                }
             }
         }
     }
@@ -316,7 +182,7 @@ void * mca_mpool_base_alloc(size_t size, ompi_info_t * info)
         num_modules++;
     }
     
-    while(i < reg_module_num && MCA_MPOOL_BASE_MAX_REG > num_modules)
+    while(i < reg_module_num)
     {
         mca_mpool_base_module_t* mpool = has_reg_function[i]->mpool_module;
         if(OMPI_SUCCESS != mpool->mpool_register(mpool, mem, size, MCA_MPOOL_FLAGS_PERSIST,  &registration))
diff --git a/ompi/mca/mpool/base/mpool_base_close.c b/ompi/mca/mpool/base/mpool_base_close.c
index 44373fd573..f9166d84ca 100644
--- a/ompi/mca/mpool/base/mpool_base_close.c
+++ b/ompi/mca/mpool/base/mpool_base_close.c
@@ -25,6 +25,8 @@
 #include "mca/mpool/base/base.h"
 #include "mpool_base_mem_cb.h"
 
+extern int mca_mpool_base_use_mem_hooks; 
+
 int mca_mpool_base_close(void)
 {
   opal_list_item_t *item;
@@ -55,9 +57,9 @@ int mca_mpool_base_close(void)
                             &mca_mpool_base_components, NULL);
 
   /* deregister memory free callback */
-  /* if(opal_mem_free_is_supported()) {  */
-/*       opal_mem_free_unregister_handler(mca_mpool_base_mem_cb);  */
-/*   } */
+  if(mca_mpool_base_use_mem_hooks && opal_mem_free_is_supported()) {
+      opal_mem_free_unregister_handler(mca_mpool_base_mem_cb);
+  }
   /* All done */
 
   return OMPI_SUCCESS;
diff --git a/ompi/mca/mpool/base/mpool_base_init.c b/ompi/mca/mpool/base/mpool_base_init.c
index 7010b3fda0..5835c63158 100644
--- a/ompi/mca/mpool/base/mpool_base_init.c
+++ b/ompi/mca/mpool/base/mpool_base_init.c
@@ -44,12 +44,6 @@ int mca_mpool_base_init(bool enable_progress_threads, bool enable_mpi_threads)
 {
     mca_mpool_enable_progress_threads = enable_progress_threads;
     mca_mpool_enable_mpi_threads = enable_mpi_threads;
-    OBJ_CONSTRUCT(&mca_mpool_base_mem_list, ompi_free_list_t);
-    ompi_free_list_init(&mca_mpool_base_mem_list, sizeof(mca_mpool_base_chunk_t),
-                        OBJ_CLASS(mca_mpool_base_chunk_t), 0, -1 , 128, NULL);
-    OBJ_CONSTRUCT(&mca_mpool_base_tree, ompi_rb_tree_t);
-    OBJ_CONSTRUCT(&mca_mpool_base_tree_lock, opal_mutex_t); 
-
-    return ompi_rb_tree_init(&mca_mpool_base_tree, mca_mpool_base_tree_node_compare);
+    return OMPI_SUCCESS;
 }
 
diff --git a/ompi/mca/mpool/base/mpool_base_lookup.c b/ompi/mca/mpool/base/mpool_base_lookup.c
index f9810dd615..b981b8fef9 100644
--- a/ompi/mca/mpool/base/mpool_base_lookup.c
+++ b/ompi/mca/mpool/base/mpool_base_lookup.c
@@ -25,6 +25,7 @@
 #include "mca/mpool/base/base.h"
 #include "mpool_base_mem_cb.h"
 
+extern int mca_mpool_base_use_mem_hooks;
 
 mca_mpool_base_component_t* mca_mpool_base_component_lookup(const char* name)
 {
@@ -79,10 +80,11 @@ mca_mpool_base_module_t* mca_mpool_base_module_create(
     sm->mpool_resources = resources;
     opal_list_append(&mca_mpool_base_modules, (opal_list_item_t*) sm); 
     /* on the very first creation of a module we init the memory callback*/ 
-    /* if(opal_list_get_size(&mca_mpool_base_modules) == 1 && */
-/*        opal_mem_free_is_supported()) {  */
-/*         opal_mem_free_register_handler(mca_mpool_base_mem_cb, NULL);  */
-/*     } */
+    if(mca_mpool_base_use_mem_hooks &&
+       opal_list_get_size(&mca_mpool_base_modules) == 1 &&
+       opal_mem_free_is_supported()) {
+        opal_mem_free_register_handler(mca_mpool_base_mem_cb, NULL);
+    }
     return module; 
 }
 
diff --git a/ompi/mca/mpool/base/mpool_base_open.c b/ompi/mca/mpool/base/mpool_base_open.c
index e16cedfc12..028c47de9c 100644
--- a/ompi/mca/mpool/base/mpool_base_open.c
+++ b/ompi/mca/mpool/base/mpool_base_open.c
@@ -41,6 +41,7 @@
  * Global variables
  */
 int mca_mpool_base_output = -1;
+int mca_mpool_base_use_mem_hooks = 0; 
 opal_list_t mca_mpool_base_components;
 opal_list_t mca_mpool_base_modules;
 
@@ -59,13 +60,21 @@ int mca_mpool_base_open(void)
                                &mca_mpool_base_components, true)) {
     return OMPI_ERROR;
   }
-
+  
   /* Initialize the list so that in mca_mpool_base_close(), we can
      iterate over it (even if it's empty, as in the case of
      ompi_info) */
 
   OBJ_CONSTRUCT(&mca_mpool_base_modules, opal_list_t);
-
+  
+  mca_base_param_reg_int_name("mpool_base", 
+                              "use_mem_hooks", 
+                              "use memory hooks for deregistering freed memory",
+                              false, 
+                              false, 
+                              0,
+                              &mca_mpool_base_use_mem_hooks); 
+        
   /* All done */
 
   return OMPI_SUCCESS;
diff --git a/ompi/mca/mpool/gm/mpool_gm_module.c b/ompi/mca/mpool/gm/mpool_gm_module.c
index df1fc0a4c2..5976c6a558 100644
--- a/ompi/mca/mpool/gm/mpool_gm_module.c
+++ b/ompi/mca/mpool/gm/mpool_gm_module.c
@@ -40,6 +40,7 @@ void mca_mpool_gm_module_init(mca_mpool_gm_module_t* mpool)
     mpool->super.mpool_finalize = NULL; 
     mpool->super.rcache = 
         mca_rcache_base_module_create(mca_mpool_gm_component.rcache_name);
+    mpool->super.flags = MCA_MPOOL_FLAGS_MPI_ALLOC_MEM; 
 }
 
 
diff --git a/ompi/mca/mpool/mpool.h b/ompi/mca/mpool/mpool.h
index 29415926ec..37827cb06c 100644
--- a/ompi/mca/mpool/mpool.h
+++ b/ompi/mca/mpool/mpool.h
@@ -26,6 +26,7 @@
 
 #define MCA_MPOOL_FLAGS_CACHE 0x1
 #define MCA_MPOOL_FLAGS_PERSIST 0x2 
+#define MCA_MPOOL_FLAGS_MPI_ALLOC_MEM 0x4
 
 struct mca_mpool_base_resources_t;
 
@@ -186,6 +187,7 @@ struct mca_mpool_base_module_t {
     mca_mpool_base_module_release_fn_t mpool_release; /**< release a regisrtation from the cache */ 
     mca_mpool_base_module_finalize_fn_t mpool_finalize;  /**< finalize */
     struct mca_rcache_base_module_t *rcache; /* the rcache associated with this mpool */ 
+    uint32_t flags; /**< mpool flags */
 };
 /**
  * Convenience typedef
diff --git a/ompi/mca/mpool/mvapi/mpool_mvapi_module.c b/ompi/mca/mpool/mvapi/mpool_mvapi_module.c
index abed581d64..313fd20a24 100644
--- a/ompi/mca/mpool/mvapi/mpool_mvapi_module.c
+++ b/ompi/mca/mpool/mvapi/mpool_mvapi_module.c
@@ -45,6 +45,7 @@ void mca_mpool_mvapi_module_init(mca_mpool_mvapi_module_t* mpool)
     mpool->super.mpool_finalize = NULL; 
     mpool->super.rcache = 
         mca_rcache_base_module_create(mca_mpool_mvapi_component.rcache_name);
+    mpool->super.flags = MCA_MPOOL_FLAGS_MPI_ALLOC_MEM; 
 }
 
 
diff --git a/ompi/mca/mpool/openib/mpool_openib_module.c b/ompi/mca/mpool/openib/mpool_openib_module.c
index 99291423f8..5ff67ad5fd 100644
--- a/ompi/mca/mpool/openib/mpool_openib_module.c
+++ b/ompi/mca/mpool/openib/mpool_openib_module.c
@@ -42,7 +42,7 @@ void mca_mpool_openib_module_init(mca_mpool_openib_module_t* mpool)
     mpool->super.mpool_finalize = NULL; 
     mpool->super.rcache = 
         mca_rcache_base_module_create(mca_mpool_openib_component.rcache_name);
-    
+    mpool->super.flags = MCA_MPOOL_FLAGS_MPI_ALLOC_MEM; 
 }
 
 
diff --git a/ompi/mca/mpool/sm/mpool_sm_module.c b/ompi/mca/mpool/sm/mpool_sm_module.c
index 0786da0faa..817d89bfd5 100644
--- a/ompi/mca/mpool/sm/mpool_sm_module.c
+++ b/ompi/mca/mpool/sm/mpool_sm_module.c
@@ -34,7 +34,7 @@ void mca_mpool_sm_module_init(mca_mpool_sm_module_t* mpool)
   mpool->super.mpool_register = NULL; 
   mpool->super.mpool_deregister = NULL; 
   mpool->super.mpool_finalize = NULL; 
-
+  mpool->super.flags = 0;
 }
 
 /*