--- old/src/share/vm/gc_implementation/parallelScavenge/generationSizer.hpp	2013-10-25 15:32:40.000000000 +0200
+++ new/src/share/vm/gc_implementation/parallelScavenge/generationSizer.hpp	2013-10-25 15:32:40.000000000 +0200
@@ -31,11 +31,23 @@
 // TwoGenerationCollectorPolicy. Lets reuse it!
 
 class GenerationSizer : public TwoGenerationCollectorPolicy {
- public:
-  GenerationSizer() {
-    // Partial init only!
-    initialize_flags();
-    initialize_size_info();
+private:
+
+  void trace_gen_sizes(const char* const str) {
+    if (TracePageSizes) {
+      tty->print_cr("%s:  " SIZE_FORMAT "," SIZE_FORMAT " "
+                    SIZE_FORMAT "," SIZE_FORMAT " "
+                    SIZE_FORMAT,
+                    str,
+                    _min_gen1_size / K, _max_gen1_size / K,
+                    _min_gen0_size / K, _max_gen0_size / K,
+                    _max_heap_byte_size / K);
+    }
+  }
+
+  void initialize_alignments() {
+    _space_alignment = _gen_alignment = default_gen_alignment();
+    _heap_alignment = compute_heap_alignment();
   }
 
   void initialize_flags() {
@@ -51,21 +63,32 @@
     // default gc, which adds 2 to the ratio value. We need to
     // make sure the values are valid before using them.
     if (MinSurvivorRatio < 3) {
-      MinSurvivorRatio = 3;
+      FLAG_SET_ERGO(uintx, MinSurvivorRatio, 3);
     }
 
     if (InitialSurvivorRatio < 3) {
-      InitialSurvivorRatio = 3;
+      FLAG_SET_ERGO(uintx, InitialSurvivorRatio, 3);
     }
   }
 
-  size_t min_young_gen_size() { return _min_gen0_size; }
-  size_t young_gen_size()     { return _initial_gen0_size; }
-  size_t max_young_gen_size() { return _max_gen0_size; }
-
-  size_t min_old_gen_size()   { return _min_gen1_size; }
-  size_t old_gen_size()       { return _initial_gen1_size; }
-  size_t max_old_gen_size()   { return _max_gen1_size; }
+  void initialize_size_info() {
+    trace_gen_sizes("ps heap raw");
+    const size_t page_sz = os::page_size_for_region(_min_heap_byte_size,
+                                                    _max_heap_byte_size,
+                                                    8);
+
+    // Can a page size be something else than a power of two?
+    assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");
+    size_t new_alignment = round_to(page_sz, _gen_alignment);
+    if (new_alignment != _gen_alignment) {
+      _gen_alignment = new_alignment;
+      // Redo everything from the start
+      initialize_flags();
+    }
+    TwoGenerationCollectorPolicy::initialize_size_info();
+
+    trace_gen_sizes("ps heap rnd");
+  }
 };
 
 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_GENERATIONSIZER_HPP