--- a/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp	Fri Mar 21 16:36:59 2014 -0700
+++ b/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp	Mon Mar 24 21:30:43 2014 +0100
@@ -280,16 +280,6 @@
       if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
           ((gc_cause != GCCause::_java_lang_system_gc) ||
             UseAdaptiveSizePolicyWithSystemGC)) {
-        // Swap the survivor spaces if from_space is empty. The
-        // resize_young_gen() called below is normally used after
-        // a successful young GC and swapping of survivor spaces;
-        // otherwise, it will fail to resize the young gen with
-        // the current implementation.
-        if (young_gen->from_space()->is_empty()) {
-          young_gen->from_space()->clear(SpaceDecorator::Mangle);
-          young_gen->swap_spaces();
-        }
-
         // Calculate optimal free space amounts
         assert(young_gen->max_size() >
           young_gen->from_space()->capacity_in_bytes() +
@@ -328,8 +318,12 @@
 
         heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
 
-        heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
-                               size_policy->calculated_survivor_size_in_bytes());
+        // Don't resize the young generation at an major collection.  A
+        // desired young generation size may have been calculated but
+        // resizing the young generation complicates the code because the
+        // resizing of the old generation may have moved the boundary
+        // between the young generation and the old generation.  Let the
+        // young generation resizing happen at the minor collections.
       }
       if (PrintAdaptiveSizePolicy) {
         gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",