Something not quite right about the revised allocation algos, so revert them while retaining the larger initial and threshold sizes

Signed-off-by: Ralph Castain <rhc@open-mpi.org>

opal/dss/dss_internal_functions.c

@@ -36,7 +36,6 @@ char* opal_dss_buffer_extend(opal_buffer_t *buffer, size_t bytes_to_add)
 {
     size_t required, to_alloc;
     size_t pack_offset, unpack_offset;
-    char *tmp;
 
     /* Check to see if we have enough space already */
 
@@ -45,19 +44,34 @@ char* opal_dss_buffer_extend(opal_buffer_t *buffer, size_t bytes_to_add)
     }
 
     required = buffer->bytes_used + bytes_to_add;
-    if (required >= (size_t)opal_dss_threshold_size) {
-        to_alloc = (required + opal_dss_threshold_size - 1) & ~(opal_dss_threshold_size - 1);
+    if(required >= (size_t)opal_dss_threshold_size) {
+        to_alloc = ((required + opal_dss_threshold_size - 1)
+                    / opal_dss_threshold_size) * opal_dss_threshold_size;
     } else {
-        to_alloc = buffer->bytes_allocated ? buffer->bytes_allocated : (size_t)opal_dss_initial_size;
+        to_alloc = buffer->bytes_allocated;
+        if(0 == to_alloc) {
+            to_alloc = opal_dss_initial_size;
+        }
+        while(to_alloc < required) {
+            to_alloc <<= 1;
+        }
     }
 
+    if (NULL != buffer->base_ptr) {
         pack_offset = ((char*) buffer->pack_ptr) - ((char*) buffer->base_ptr);
-    unpack_offset = ((char*) buffer->unpack_ptr) - ((char*) buffer->base_ptr);
-    tmp = (char*)realloc(buffer->base_ptr, to_alloc);
-    if (NULL == tmp) {
+        unpack_offset = ((char*) buffer->unpack_ptr) -
+            ((char*) buffer->base_ptr);
+        buffer->base_ptr = (char*)realloc(buffer->base_ptr, to_alloc);
+    } else {
+        pack_offset = 0;
+        unpack_offset = 0;
+        buffer->bytes_used = 0;
+        buffer->base_ptr = (char*)malloc(to_alloc);
+    }
+
+    if (NULL == buffer->base_ptr) {
         return NULL;
     }
-    buffer->base_ptr = tmp;
     buffer->pack_ptr = ((char*) buffer->base_ptr) + pack_offset;
     buffer->unpack_ptr = ((char*) buffer->base_ptr) + unpack_offset;
     buffer->bytes_allocated = to_alloc;