--- old/src/hotspot/share/memory/metaspace/metachunk.cpp	2019-07-25 15:29:45.549180120 +0200
+++ new/src/hotspot/share/memory/metaspace/metachunk.cpp	2019-07-25 15:29:45.329176997 +0200
@@ -22,151 +22,148 @@
  *
  */
 
+
 #include "precompiled.hpp"
-#include "memory/allocation.hpp"
+
+#include "memory/metaspace/chunkLevel.hpp"
+#include "memory/metaspace/constants.hpp"
 #include "memory/metaspace/metachunk.hpp"
-#include "memory/metaspace/occupancyMap.hpp"
+#include "memory/metaspace/metaspaceCommon.hpp"
 #include "memory/metaspace/virtualSpaceNode.hpp"
+
 #include "utilities/align.hpp"
 #include "utilities/copy.hpp"
 #include "utilities/debug.hpp"
 
 namespace metaspace {
 
-size_t Metachunk::object_alignment() {
-  // Must align pointers and sizes to 8,
-  // so that 64 bit types get correctly aligned.
-  const size_t alignment = 8;
-
-  // Make sure that the Klass alignment also agree.
-  STATIC_ASSERT(alignment == (size_t)KlassAlignmentInBytes);
-
-  return alignment;
-}
-
-size_t Metachunk::overhead() {
-  return align_up(sizeof(Metachunk), object_alignment()) / BytesPerWord;
-}
-
-// Metachunk methods
-
-Metachunk::Metachunk(ChunkIndex chunktype, bool is_class, size_t word_size,
-                     VirtualSpaceNode* container)
-    : Metabase<Metachunk>(word_size),
-    _container(container),
-    _top(NULL),
-    _sentinel(CHUNK_SENTINEL),
-    _chunk_type(chunktype),
-    _is_class(is_class),
-    _origin(origin_normal),
-    _use_count(0)
-{
-  _top = initial_top();
-  set_is_tagged_free(false);
-#ifdef ASSERT
-  mangle(uninitMetaWordVal);
-  verify();
-#endif
-}
+// Make sure that the Klass alignment also agree.
+STATIC_ASSERT(Metachunk::allocation_alignment_bytes == (size_t)KlassAlignmentInBytes);
 
-MetaWord* Metachunk::allocate(size_t word_size) {
-  MetaWord* result = NULL;
-  // If available, bump the pointer to allocate.
-  if (free_word_size() >= word_size) {
-    result = _top;
-    _top = _top + word_size;
+void Metachunk::remove_from_list() {
+  if (_prev != NULL) {
+    _prev->set_next(_next);
   }
-  return result;
+  if (_next != NULL) {
+    _next->set_prev(_prev);
+  }
+  _prev = _next = NULL;
 }
 
-// _bottom points to the start of the chunk including the overhead.
-size_t Metachunk::used_word_size() const {
-  return pointer_delta(_top, bottom(), sizeof(MetaWord));
-}
+// Ensure that chunk is committed up to at least word_size words.
+bool Metachunk::ensure_committed(size_t new_committed_words) {
+
+  assert(new_committed_words <= word_size(), "too much.");
+
+  if (new_committed_words <= committed_words()) {
+    return true;
+  }
+
+  // Note: we may commit more than the area of our own chunk and that is okay.
+  MetaWord* const commit_top = align_down(base() + committed_words(), constants::commit_granule_words);
+  MetaWord* const new_commit_top = align_up(base() + new_committed_words, constants::commit_granule_words);
+
+  {
+    // Expand lock from here on.
+    MutexLocker cl(MetaspaceExpand_lock, Mutex::_no_safepoint_check_flag);
+    if (!_vsnode->ensure_range_is_committed(commit_top, new_commit_top - commit_top)) {
+      return false;
+    }
+    // Remember how far we have committed.
+    _committed_words = new_commit_top - base();
+    if (_committed_words > word_size()) {
+      _committed_words = word_size();
+    }
+  }
+
+  return true;
 
-size_t Metachunk::free_word_size() const {
-  return pointer_delta(end(), _top, sizeof(MetaWord));
 }
 
-void Metachunk::print_on(outputStream* st) const {
-  st->print_cr("Metachunk:"
-               " bottom " PTR_FORMAT " top " PTR_FORMAT
-               " end " PTR_FORMAT " size " SIZE_FORMAT " (%s)",
-               p2i(bottom()), p2i(_top), p2i(end()), word_size(),
-               chunk_size_name(get_chunk_type()));
-  if (Verbose) {
-    st->print_cr("    used " SIZE_FORMAT " free " SIZE_FORMAT,
-                 used_word_size(), free_word_size());
+
+// Allocate word_size words from this chunk.
+//
+// May cause memory to be committed. That may fail if we hit a commit limit. In that case,
+//  NULL is returned and p_did_hit_commit_limit will be set to true.
+// If the remainder portion of the chunk was too small to hold the allocation,
+//  NULL is returned and p_did_hit_commit_limit will be set to false.
+MetaWord* Metachunk::allocate(size_t word_size, bool* p_did_hit_commit_limit) {
+
+  size_t request_word_size = align_up(word_size, allocation_alignment_words);
+
+  // Space enough left?
+  if (free_words() < request_word_size) {
+    *p_did_hit_commit_limit = false;
+    return NULL;
+  }
+
+  // Expand committed region if necessary.
+  if (ensure_committed(used_words() + request_word_size) == false) {
+    *p_did_hit_commit_limit = true;
+    return NULL;
   }
+
+  MetaWord* const p = top();
+
+  _used_words += request_word_size;
+
+  return p;
+
 }
 
 #ifdef ASSERT
-void Metachunk::mangle(juint word_value) {
-  // Overwrite the payload of the chunk and not the links that
-  // maintain list of chunks.
-  HeapWord* start = (HeapWord*)initial_top();
-  size_t size = word_size() - overhead();
-  Copy::fill_to_words(start, size, word_value);
-}
-
-void Metachunk::verify() const {
-  assert(is_valid_sentinel(), "Chunk " PTR_FORMAT ": sentinel invalid", p2i(this));
-  const ChunkIndex chunk_type = get_chunk_type();
-  assert(is_valid_chunktype(chunk_type), "Chunk " PTR_FORMAT ": Invalid chunk type.", p2i(this));
-  if (chunk_type != HumongousIndex) {
-    assert(word_size() == get_size_for_nonhumongous_chunktype(chunk_type, is_class()),
-           "Chunk " PTR_FORMAT ": wordsize " SIZE_FORMAT " does not fit chunk type %s.",
-           p2i(this), word_size(), chunk_size_name(chunk_type));
-  }
-  assert(is_valid_chunkorigin(get_origin()), "Chunk " PTR_FORMAT ": Invalid chunk origin.", p2i(this));
-  assert(bottom() <= _top && _top <= (MetaWord*)end(),
-         "Chunk " PTR_FORMAT ": Chunk top out of chunk bounds.", p2i(this));
-
-  // For non-humongous chunks, starting address shall be aligned
-  // to its chunk size. Humongous chunks start address is
-  // aligned to specialized chunk size.
-  const size_t required_alignment =
-    (chunk_type != HumongousIndex ? word_size() : get_size_for_nonhumongous_chunktype(SpecializedIndex, is_class())) * sizeof(MetaWord);
-  assert(is_aligned((address)this, required_alignment),
-         "Chunk " PTR_FORMAT ": (size " SIZE_FORMAT ") not aligned to " SIZE_FORMAT ".",
-         p2i(this), word_size() * sizeof(MetaWord), required_alignment);
-}
 
+void Metachunk::verify(bool slow) const {
+
+  // Note: only call this on a life Metachunk.
+  chklvl::check_valid_level(level());
+
+  assert(base() != NULL, "No base ptr");
+  assert(committed_words() >= used_words(), "Sanity");
+  assert(word_size() >= committed_words(), "Sanity");
+
+  // Test base pointer
+  assert(vsnode() != NULL, "No space");
+  vsnode()->check_pointer(base());
+  assert(base() != NULL, "Base pointer NULL");
+
+  // Starting address shall be aligned to chunk size.
+  const size_t required_alignment = word_size() * sizeof(MetaWord);
+  assert_is_aligned(base(), required_alignment);
+
+  // Used words
+  assert(used_words() < word_size(), "oob");
+
+  // If we are not a root chunk, we shall have a reference to a tree node
+  assert(tree_node_ref() != 0 || level() == chklvl::ROOT_CHUNK_LEVEL, "No parent node.");
+
+}
 #endif // ASSERT
 
-// Helper, returns a descriptive name for the given index.
-const char* chunk_size_name(ChunkIndex index) {
-  switch (index) {
-    case SpecializedIndex:
-      return "specialized";
-    case SmallIndex:
-      return "small";
-    case MediumIndex:
-      return "medium";
-    case HumongousIndex:
-      return "humongous";
-    default:
-      return "Invalid index";
+
+#ifdef ASSERT
+
+bool MetachunkList::contains(const Metachunk* c) const {
+  for (Metachunk* c2 = first(); c2 != NULL; c2 = c2->next()) {
+    if (c == c2) {
+      return true;
+    }
   }
+  return false;
 }
 
-#ifdef ASSERT
-void do_verify_chunk(Metachunk* chunk) {
-  guarantee(chunk != NULL, "Sanity");
-  // Verify chunk itself; then verify that it is consistent with the
-  // occupany map of its containing node.
-  chunk->verify();
-  VirtualSpaceNode* const vsn = chunk->container();
-  OccupancyMap* const ocmap = vsn->occupancy_map();
-  ocmap->verify_for_chunk(chunk);
-}
-#endif
-
-void do_update_in_use_info_for_chunk(Metachunk* chunk, bool inuse) {
-  chunk->set_is_tagged_free(!inuse);
-  OccupancyMap* const ocmap = chunk->container()->occupancy_map();
-  ocmap->set_region_in_use((MetaWord*)chunk, chunk->word_size(), inuse);
+void MetachunkList::verify(bool slow) const {
+  int num = 0;
+  for (Metachunk* c = first(); c != NULL; c = c->next()) {
+    num ++;
+    if (slow) {
+      c->verify(false);
+    }
+    _num.check(num);
+  }
 }
 
+#endif // ASSERT
+
 } // namespace metaspace