8010722: assert: failed: heap size is too big for compressed oops

Use conservative assumptions of required alignment for the various garbage collector components into account when determining the maximum heap size that supports compressed oops. Using this conservative value avoids several circular dependencies in the calculation.

Reviewed-by: stefank, dholmes

hotspot/src/share/vm/memory/collectorPolicy.cpp

@@ -145,6 +145,30 @@ void CollectorPolicy::cleared_all_soft_refs() {
   _all_soft_refs_clear = true;
 }
 
+size_t CollectorPolicy::compute_max_alignment() {
+  // The card marking array and the offset arrays for old generations are
+  // committed in os pages as well. Make sure they are entirely full (to
+  // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
+  // byte entry and the os page size is 4096, the maximum heap size should
+  // be 512*4096 = 2MB aligned.
+
+  // There is only the GenRemSet in Hotspot and only the GenRemSet::CardTable
+  // is supported.
+  // Requirements of any new remembered set implementations must be added here.
+  size_t alignment = GenRemSet::max_alignment_constraint(GenRemSet::CardTable);
+
+  // Parallel GC does its own alignment of the generations to avoid requiring a
+  // large page (256M on some platforms) for the permanent generation.  The
+  // other collectors should also be updated to do their own alignment and then
+  // this use of lcm() should be removed.
+  if (UseLargePages && !UseParallelGC) {
+      // in presence of large pages we have to make sure that our
+      // alignment is large page aware
+      alignment = lcm(os::large_page_size(), alignment);
+  }
+
+  return alignment;
+}
 
 // GenCollectorPolicy methods.
 
@@ -175,29 +199,6 @@ void GenCollectorPolicy::initialize_size_policy(size_t init_eden_size,
                                         GCTimeRatio);
 }
 
-size_t GenCollectorPolicy::compute_max_alignment() {
-  // The card marking array and the offset arrays for old generations are
-  // committed in os pages as well. Make sure they are entirely full (to
-  // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
-  // byte entry and the os page size is 4096, the maximum heap size should
-  // be 512*4096 = 2MB aligned.
-  size_t alignment = GenRemSet::max_alignment_constraint(rem_set_name());
-
-  // Parallel GC does its own alignment of the generations to avoid requiring a
-  // large page (256M on some platforms) for the permanent generation.  The
-  // other collectors should also be updated to do their own alignment and then
-  // this use of lcm() should be removed.
-  if (UseLargePages && !UseParallelGC) {
-      // in presence of large pages we have to make sure that our
-      // alignment is large page aware
-      alignment = lcm(os::large_page_size(), alignment);
-  }
-
-  assert(alignment >= min_alignment(), "Must be");
-
-  return alignment;
-}
-
 void GenCollectorPolicy::initialize_flags() {
   // All sizes must be multiples of the generation granularity.
   set_min_alignment((uintx) Generation::GenGrain);

hotspot/src/share/vm/memory/collectorPolicy.hpp

@@ -98,6 +98,9 @@ class CollectorPolicy : public CHeapObj<mtGC> {
   {}
 
  public:
+  // Return maximum heap alignment that may be imposed by the policy
+  static size_t compute_max_alignment();
+
   void set_min_alignment(size_t align)         { _min_alignment = align; }
   size_t min_alignment()                       { return _min_alignment; }
   void set_max_alignment(size_t align)         { _max_alignment = align; }
@@ -234,9 +237,6 @@ class GenCollectorPolicy : public CollectorPolicy {
   // Try to allocate space by expanding the heap.
   virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab);
 
-  // compute max heap alignment
-  size_t compute_max_alignment();
-
  // Scale the base_size by NewRation according to
  //     result = base_size / (NewRatio + 1)
  // and align by min_alignment()

hotspot/src/share/vm/memory/genCollectedHeap.hpp

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2000, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -148,6 +148,11 @@ public:
     return gen_policy()->size_policy();
   }
 
+  // Return the (conservative) maximum heap alignment
+  static size_t conservative_max_heap_alignment() {
+    return Generation::GenGrain;
+  }
+
   size_t capacity() const;
   size_t used() const;
 

hotspot/src/share/vm/memory/universe.cpp

@@ -872,6 +872,9 @@ jint Universe::initialize_heap() {
 
 // Reserve the Java heap, which is now the same for all GCs.
 ReservedSpace Universe::reserve_heap(size_t heap_size, size_t alignment) {
+  assert(alignment <= Arguments::conservative_max_heap_alignment(),
+      err_msg("actual alignment "SIZE_FORMAT" must be within maximum heap alignment "SIZE_FORMAT,
+          alignment, Arguments::conservative_max_heap_alignment()));
   size_t total_reserved = align_size_up(heap_size, alignment);
   assert(!UseCompressedOops || (total_reserved <= (OopEncodingHeapMax - os::vm_page_size())),
       "heap size is too big for compressed oops");