--- a/hotspot/src/share/vm/memory/collectorPolicy.cpp	Mon May 06 13:03:46 2013 +0200
+++ b/hotspot/src/share/vm/memory/collectorPolicy.cpp	Mon May 06 17:19:42 2013 +0200
@@ -55,6 +55,10 @@
       err_msg("max_alignment: " SIZE_FORMAT " not aligned by min_alignment: " SIZE_FORMAT,
           max_alignment(), min_alignment()));
 
+  if (MaxHeapSize < InitialHeapSize) {
+    vm_exit_during_initialization("Incompatible initial and maximum heap sizes specified");
+  }
+
   if (MetaspaceSize > MaxMetaspaceSize) {
     MaxMetaspaceSize = MetaspaceSize;
   }
@@ -78,21 +82,9 @@
 }
 
 void CollectorPolicy::initialize_size_info() {
-  // User inputs from -mx and ms are aligned
-  set_initial_heap_byte_size(InitialHeapSize);
-  if (initial_heap_byte_size() == 0) {
-    set_initial_heap_byte_size(NewSize + OldSize);
-  }
-  set_initial_heap_byte_size(align_size_up(_initial_heap_byte_size,
-                                           min_alignment()));
-
-  set_min_heap_byte_size(Arguments::min_heap_size());
-  if (min_heap_byte_size() == 0) {
-    set_min_heap_byte_size(NewSize + OldSize);
-  }
-  set_min_heap_byte_size(align_size_up(_min_heap_byte_size,
-                                       min_alignment()));
-
+  // User inputs from -mx and ms must be aligned
+  set_min_heap_byte_size(align_size_up(Arguments::min_heap_size(), min_alignment()));
+  set_initial_heap_byte_size(align_size_up(InitialHeapSize, min_alignment()));
   set_max_heap_byte_size(align_size_up(MaxHeapSize, max_alignment()));
 
   // Check heap parameter properties
@@ -237,9 +229,6 @@
   GenCollectorPolicy::initialize_flags();
 
   OldSize = align_size_down(OldSize, min_alignment());
-  if (NewSize + OldSize > MaxHeapSize) {
-    MaxHeapSize = NewSize + OldSize;
-  }
 
   if (FLAG_IS_CMDLINE(OldSize) && FLAG_IS_DEFAULT(NewSize)) {
     // NewRatio will be used later to set the young generation size so we use
@@ -254,6 +243,27 @@
   }
   MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
 
+  // adjust max heap size if necessary
+  if (NewSize + OldSize > MaxHeapSize) {
+    if (FLAG_IS_CMDLINE(MaxHeapSize)) {
+      // somebody set a maximum heap size with the intention that we should not
+      // exceed it. Adjust New/OldSize as necessary.
+      uintx calculated_size = NewSize + OldSize;
+      double shrink_factor = (double) MaxHeapSize / calculated_size;
+      // align
+      NewSize = align_size_down((uintx) (NewSize * shrink_factor), min_alignment());
+      // OldSize is already aligned because above we aligned MaxHeapSize to
+      // max_alignment(), and we just made sure that NewSize is aligned to
+      // min_alignment(). In initialize_flags() we verified that max_alignment()
+      // is a multiple of min_alignment().
+      OldSize = MaxHeapSize - NewSize;
+    } else {
+      MaxHeapSize = NewSize + OldSize;
+    }
+  }
+  // need to do this again
+  MaxHeapSize = align_size_up(MaxHeapSize, max_alignment());
+
   always_do_update_barrier = UseConcMarkSweepGC;
 
   // Check validity of heap flags

--- a/hotspot/src/share/vm/prims/whitebox.cpp	Mon May 06 13:03:46 2013 +0200
+++ b/hotspot/src/share/vm/prims/whitebox.cpp	Mon May 06 17:19:42 2013 +0200
@@ -93,6 +93,15 @@
   return closure.found();
 WB_END
 
+WB_ENTRY(void, WB_PrintHeapSizes(JNIEnv* env, jobject o)) {
+  CollectorPolicy * p = Universe::heap()->collector_policy();
+  gclog_or_tty->print_cr("Minimum heap "SIZE_FORMAT" Initial heap "
+    SIZE_FORMAT" Maximum heap "SIZE_FORMAT" Min alignment "SIZE_FORMAT" Max alignment "SIZE_FORMAT,
+    p->min_heap_byte_size(), p->initial_heap_byte_size(), p->max_heap_byte_size(),
+    p->min_alignment(), p->max_alignment());
+}
+WB_END
+
 #if INCLUDE_ALL_GCS
 WB_ENTRY(jboolean, WB_G1IsHumongous(JNIEnv* env, jobject o, jobject obj))
   G1CollectedHeap* g1 = G1CollectedHeap::heap();
@@ -386,6 +395,7 @@
       CC"(Ljava/lang/String;[Lsun/hotspot/parser/DiagnosticCommand;)[Ljava/lang/Object;",
       (void*) &WB_ParseCommandLine
   },
+  {CC"printHeapSizes",     CC"()V",                   (void*)&WB_PrintHeapSizes    },
 #if INCLUDE_ALL_GCS
   {CC"g1InConcurrentMark", CC"()Z",                   (void*)&WB_G1InConcurrentMark},
   {CC"g1IsHumongous",      CC"(Ljava/lang/Object;)Z", (void*)&WB_G1IsHumongous     },

--- a/hotspot/src/share/vm/runtime/arguments.cpp	Mon May 06 13:03:46 2013 +0200
+++ b/hotspot/src/share/vm/runtime/arguments.cpp	Mon May 06 17:19:42 2013 +0200
@@ -1617,30 +1617,38 @@
     FLAG_SET_ERGO(uintx, MaxHeapSize, (uintx)reasonable_max);
   }
 
-  // If the initial_heap_size has not been set with InitialHeapSize
-  // or -Xms, then set it as fraction of the size of physical memory,
-  // respecting the maximum and minimum sizes of the heap.
-  if (FLAG_IS_DEFAULT(InitialHeapSize)) {
+  // If the minimum or initial heap_size have not been set or requested to be set
+  // ergonomically, set them accordingly.
+  if (InitialHeapSize == 0 || min_heap_size() == 0) {
     julong reasonable_minimum = (julong)(OldSize + NewSize);
 
     reasonable_minimum = MIN2(reasonable_minimum, (julong)MaxHeapSize);
 
     reasonable_minimum = limit_by_allocatable_memory(reasonable_minimum);
 
-    julong reasonable_initial = phys_mem / InitialRAMFraction;
-
-    reasonable_initial = MAX2(reasonable_initial, reasonable_minimum);
-    reasonable_initial = MIN2(reasonable_initial, (julong)MaxHeapSize);
-
-    reasonable_initial = limit_by_allocatable_memory(reasonable_initial);
-
-    if (PrintGCDetails && Verbose) {
-      // Cannot use gclog_or_tty yet.
-      tty->print_cr("  Initial heap size " SIZE_FORMAT, (uintx)reasonable_initial);
-      tty->print_cr("  Minimum heap size " SIZE_FORMAT, (uintx)reasonable_minimum);
+    if (InitialHeapSize == 0) {
+      julong reasonable_initial = phys_mem / InitialRAMFraction;
+
+      reasonable_initial = MAX3(reasonable_initial, reasonable_minimum, (julong)min_heap_size());
+      reasonable_initial = MIN2(reasonable_initial, (julong)MaxHeapSize);
+
+      reasonable_initial = limit_by_allocatable_memory(reasonable_initial);
+
+      if (PrintGCDetails && Verbose) {
+        // Cannot use gclog_or_tty yet.
+        tty->print_cr("  Initial heap size " SIZE_FORMAT, (uintx)reasonable_initial);
+      }
+      FLAG_SET_ERGO(uintx, InitialHeapSize, (uintx)reasonable_initial);
     }
-    FLAG_SET_ERGO(uintx, InitialHeapSize, (uintx)reasonable_initial);
-    set_min_heap_size((uintx)reasonable_minimum);
+    // If the minimum heap size has not been set (via -Xms),
+    // synchronize with InitialHeapSize to avoid errors with the default value.
+    if (min_heap_size() == 0) {
+      set_min_heap_size(MIN2((uintx)reasonable_minimum, InitialHeapSize));
+      if (PrintGCDetails && Verbose) {
+        // Cannot use gclog_or_tty yet.
+        tty->print_cr("  Minimum heap size " SIZE_FORMAT, min_heap_size());
+      }
+    }
   }
 }
 
@@ -2426,7 +2434,8 @@
     // -Xms
     } else if (match_option(option, "-Xms", &tail)) {
       julong long_initial_heap_size = 0;
-      ArgsRange errcode = parse_memory_size(tail, &long_initial_heap_size, 1);
+      // an initial heap size of 0 means automatically determine
+      ArgsRange errcode = parse_memory_size(tail, &long_initial_heap_size, 0);
       if (errcode != arg_in_range) {
         jio_fprintf(defaultStream::error_stream(),
                     "Invalid initial heap size: %s\n", option->optionString);
@@ -2437,7 +2446,7 @@
       // Currently the minimum size and the initial heap sizes are the same.
       set_min_heap_size(InitialHeapSize);
     // -Xmx
-    } else if (match_option(option, "-Xmx", &tail)) {
+    } else if (match_option(option, "-Xmx", &tail) || match_option(option, "-XX:MaxHeapSize=", &tail)) {
       julong long_max_heap_size = 0;
       ArgsRange errcode = parse_memory_size(tail, &long_max_heap_size, 1);
       if (errcode != arg_in_range) {

--- a/hotspot/src/share/vm/runtime/globals.hpp	Mon May 06 13:03:46 2013 +0200
+++ b/hotspot/src/share/vm/runtime/globals.hpp	Mon May 06 17:19:42 2013 +0200
@@ -2968,7 +2968,7 @@
                                                                             \
   /* gc parameters */                                                       \
   product(uintx, InitialHeapSize, 0,                                        \
-          "Initial heap size (in bytes); zero means OldSize + NewSize")     \
+          "Initial heap size (in bytes); zero means use ergonomics")        \
                                                                             \
   product(uintx, MaxHeapSize, ScaleForWordSize(96*M),                       \
           "Maximum heap size (in bytes)")                                   \

--- a/hotspot/test/testlibrary/whitebox/sun/hotspot/WhiteBox.java	Mon May 06 13:03:46 2013 +0200
+++ b/hotspot/test/testlibrary/whitebox/sun/hotspot/WhiteBox.java	Mon May 06 17:19:42 2013 +0200
@@ -61,6 +61,9 @@
     registerNatives();
   }
 
+  // Arguments
+  public native void printHeapSizes();
+
   // Memory
   public native long getObjectAddress(Object o);
   public native int  getHeapOopSize();