--- a/hotspot/src/os/bsd/vm/os_bsd.cpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/os/bsd/vm/os_bsd.cpp	Wed Mar 27 19:21:18 2013 +0100
@@ -167,20 +167,6 @@
   return Bsd::physical_memory();
 }
 
-julong os::allocatable_physical_memory(julong size) {
-#ifdef _LP64
-  return size;
-#else
-  julong result = MIN2(size, (julong)3800*M);
-   if (!is_allocatable(result)) {
-     // See comments under solaris for alignment considerations
-     julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
-     result =  MIN2(size, reasonable_size);
-   }
-   return result;
-#endif // _LP64
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // environment support
 

--- a/hotspot/src/os/linux/vm/os_linux.cpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/os/linux/vm/os_linux.cpp	Wed Mar 27 19:21:18 2013 +0100
@@ -194,20 +194,6 @@
   return Linux::physical_memory();
 }
 
-julong os::allocatable_physical_memory(julong size) {
-#ifdef _LP64
-  return size;
-#else
-  julong result = MIN2(size, (julong)3800*M);
-   if (!is_allocatable(result)) {
-     // See comments under solaris for alignment considerations
-     julong reasonable_size = (julong)2*G - 2 * os::vm_page_size();
-     result =  MIN2(size, reasonable_size);
-   }
-   return result;
-#endif // _LP64
-}
-
 ////////////////////////////////////////////////////////////////////////////////
 // environment support
 

--- a/hotspot/src/os/posix/vm/os_posix.cpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/os/posix/vm/os_posix.cpp	Wed Mar 27 19:21:18 2013 +0100
@@ -188,4 +188,66 @@
   st->cr();
 }
 
+bool os::has_allocatable_memory_limit(julong* limit) {
+  struct rlimit rlim;
+  int getrlimit_res = getrlimit(RLIMIT_AS, &rlim);
+  // if there was an error when calling getrlimit, assume that there is no limitation
+  // on virtual memory.
+  bool result;
+  if ((getrlimit_res != 0) || (rlim.rlim_cur == RLIM_INFINITY)) {
+    result = false;
+  } else {
+    *limit = (julong)rlim.rlim_cur;
+    result = true;
+  }
+#ifdef _LP64
+  return result;
+#else
+  // arbitrary virtual space limit for 32 bit Unices found by testing. If
+  // getrlimit above returned a limit, bound it with this limit. Otherwise
+  // directly use it.
+  const julong max_virtual_limit = (julong)3800*M;
+  if (result) {
+    *limit = MIN2(*limit, max_virtual_limit);
+  } else {
+    *limit = max_virtual_limit;
+  }
 
+  // bound by actually allocatable memory. The algorithm uses two bounds, an
+  // upper and a lower limit. The upper limit is the current highest amount of
+  // memory that could not be allocated, the lower limit is the current highest
+  // amount of memory that could be allocated.
+  // The algorithm iteratively refines the result by halving the difference
+  // between these limits, updating either the upper limit (if that value could
+  // not be allocated) or the lower limit (if the that value could be allocated)
+  // until the difference between these limits is "small".
+
+  // the minimum amount of memory we care about allocating.
+  const julong min_allocation_size = M;
+
+  julong upper_limit = *limit;
+
+  // first check a few trivial cases
+  if (is_allocatable(upper_limit) || (upper_limit <= min_allocation_size)) {
+    *limit = upper_limit;
+  } else if (!is_allocatable(min_allocation_size)) {
+    // we found that not even min_allocation_size is allocatable. Return it
+    // anyway. There is no point to search for a better value any more.
+    *limit = min_allocation_size;
+  } else {
+    // perform the binary search.
+    julong lower_limit = min_allocation_size;
+    while ((upper_limit - lower_limit) > min_allocation_size) {
+      julong temp_limit = ((upper_limit - lower_limit) / 2) + lower_limit;
+      temp_limit = align_size_down_(temp_limit, min_allocation_size);
+      if (is_allocatable(temp_limit)) {
+        lower_limit = temp_limit;
+      } else {
+        upper_limit = temp_limit;
+      }
+    }
+    *limit = lower_limit;
+  }
+  return true;
+#endif
+}

--- a/hotspot/src/os/solaris/vm/os_solaris.cpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/os/solaris/vm/os_solaris.cpp	Wed Mar 27 19:21:18 2013 +0100
@@ -476,24 +476,6 @@
    return Solaris::physical_memory();
 }
 
-julong os::allocatable_physical_memory(julong size) {
-#ifdef _LP64
-   return size;
-#else
-   julong result = MIN2(size, (julong)3835*M);
-   if (!is_allocatable(result)) {
-     // Memory allocations will be aligned but the alignment
-     // is not known at this point.  Alignments will
-     // be at most to LargePageSizeInBytes.  Protect
-     // allocations from alignments up to illegal
-     // values. If at this point 2G is illegal.
-     julong reasonable_size = (julong)2*G - 2 * LargePageSizeInBytes;
-     result =  MIN2(size, reasonable_size);
-   }
-   return result;
-#endif
-}
-
 static hrtime_t first_hrtime = 0;
 static const hrtime_t hrtime_hz = 1000*1000*1000;
 const int LOCK_BUSY = 1;

--- a/hotspot/src/os/windows/vm/os_windows.cpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/os/windows/vm/os_windows.cpp	Wed Mar 27 19:21:18 2013 +0100
@@ -686,12 +686,17 @@
   return win32::physical_memory();
 }
 
-julong os::allocatable_physical_memory(julong size) {
+bool os::has_allocatable_memory_limit(julong* limit) {
+  MEMORYSTATUSEX ms;
+  ms.dwLength = sizeof(ms);
+  GlobalMemoryStatusEx(&ms);
 #ifdef _LP64
-  return size;
+  *limit = (julong)ms.ullAvailVirtual;
+  return true;
 #else
   // Limit to 1400m because of the 2gb address space wall
-  return MIN2(size, (julong)1400*M);
+  *limit = MIN2((julong)1400*M, (julong)ms.ullAvailVirtual);
+  return true;
 #endif
 }
 

--- a/hotspot/src/share/vm/runtime/arguments.cpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/share/vm/runtime/arguments.cpp	Wed Mar 27 19:21:18 2013 +0100
@@ -1552,6 +1552,15 @@
   }
 }
 
+julong Arguments::limit_by_allocatable_memory(julong limit) {
+  julong max_allocatable;
+  julong result = limit;
+  if (os::has_allocatable_memory_limit(&max_allocatable)) {
+    result = MIN2(result, max_allocatable / MaxVirtMemFraction);
+  }
+  return result;
+}
+
 void Arguments::set_heap_size() {
   if (!FLAG_IS_DEFAULT(DefaultMaxRAMFraction)) {
     // Deprecated flag
@@ -1590,12 +1599,12 @@
       }
       reasonable_max = MIN2(reasonable_max, max_coop_heap);
     }
-    reasonable_max = os::allocatable_physical_memory(reasonable_max);
+    reasonable_max = limit_by_allocatable_memory(reasonable_max);
 
     if (!FLAG_IS_DEFAULT(InitialHeapSize)) {
       // An initial heap size was specified on the command line,
       // so be sure that the maximum size is consistent.  Done
-      // after call to allocatable_physical_memory because that
+      // after call to limit_by_allocatable_memory because that
       // method might reduce the allocation size.
       reasonable_max = MAX2(reasonable_max, (julong)InitialHeapSize);
     }
@@ -1615,14 +1624,14 @@
 
     reasonable_minimum = MIN2(reasonable_minimum, (julong)MaxHeapSize);
 
-    reasonable_minimum = os::allocatable_physical_memory(reasonable_minimum);
+    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 = os::allocatable_physical_memory(reasonable_initial);
+    reasonable_initial = limit_by_allocatable_memory(reasonable_initial);
 
     if (PrintGCDetails && Verbose) {
       // Cannot use gclog_or_tty yet.
@@ -2608,9 +2617,7 @@
       initHeapSize = MIN2(total_memory / (julong)2,
                           total_memory - (julong)160*M);
 
-      // Make sure that if we have a lot of memory we cap the 32 bit
-      // process space.  The 64bit VM version of this function is a nop.
-      initHeapSize = os::allocatable_physical_memory(initHeapSize);
+      initHeapSize = limit_by_allocatable_memory(initHeapSize);
 
       if (FLAG_IS_DEFAULT(MaxHeapSize)) {
          FLAG_SET_CMDLINE(uintx, MaxHeapSize, initHeapSize);

--- a/hotspot/src/share/vm/runtime/arguments.hpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/share/vm/runtime/arguments.hpp	Wed Mar 27 19:21:18 2013 +0100
@@ -312,6 +312,9 @@
   static void set_use_compressed_oops();
   static void set_ergonomics_flags();
   static void set_shared_spaces_flags();
+  // limits the given memory size by the maximum amount of memory this process is
+  // currently allowed to allocate or reserve.
+  static julong limit_by_allocatable_memory(julong size);
   // Setup heap size
   static void set_heap_size();
   // Based on automatic selection criteria, should the

--- a/hotspot/src/share/vm/runtime/globals.hpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/share/vm/runtime/globals.hpp	Wed Mar 27 19:21:18 2013 +0100
@@ -1962,6 +1962,10 @@
   product(uintx, InitialRAMFraction, 64,                                    \
           "Fraction (1/n) of real memory used for initial heap size")       \
                                                                             \
+  develop(uintx, MaxVirtMemFraction, 2,                                     \
+          "Maximum fraction (1/n) of virtual memory used for ergonomically" \
+          "determining maximum heap size")                                  \
+                                                                            \
   product(bool, UseAutoGCSelectPolicy, false,                               \
           "Use automatic collection selection policy")                      \
                                                                             \

--- a/hotspot/src/share/vm/runtime/os.hpp	Thu Mar 28 10:27:28 2013 +0100
+++ b/hotspot/src/share/vm/runtime/os.hpp	Wed Mar 27 19:21:18 2013 +0100
@@ -184,7 +184,7 @@
   }
   static julong available_memory();
   static julong physical_memory();
-  static julong allocatable_physical_memory(julong size);
+  static bool has_allocatable_memory_limit(julong* limit);
   static bool is_server_class_machine();
 
   // number of CPUs