jdk-sandbox: comparison hotspot/src/share/vm/memory/metaspace.cpp

equal deleted inserted replaced

-:d053e4e8f901
+:e851a0a007ce
 ClassSpecializedChunk = 128,
 SpecializedChunk = 128,
 ClassSmallChunk = 256,
 SmallChunk = 512,
 ClassMediumChunk = 4 * K,
-MediumChunk = 8 * K,
+MediumChunk = 8 * K
-HumongousChunkGranularity = 8
 };
 static ChunkIndex next_chunk_index(ChunkIndex i) {
 assert(i < NumberOfInUseLists, "Out of bound");
 return (ChunkIndex) (i+1);
 typedef class FreeList<Metachunk> ChunkList;
 // Manages the global free lists of chunks.
 class ChunkManager : public CHeapObj<mtInternal> {
+friend class TestVirtualSpaceNodeTest;
 // Free list of chunks of different sizes.
 //   SpecializedChunk
 //   SmallChunk
 //   MediumChunk
 // The first Metachunk will be allocated at the bottom of the
 // VirtualSpace
 Metachunk* first_chunk() { return (Metachunk*) bottom(); }
+// Committed but unused space in the virtual space
+size_t free_words_in_vs() const;
 public:
 VirtualSpaceNode(size_t byte_size);
 VirtualSpaceNode(ReservedSpace rs) : _top(NULL), _next(NULL), _rs(rs), _container_count(0) {}
 ~VirtualSpaceNode();
 #endif
 // used and capacity in this single entry in the list
 size_t used_words_in_vs() const;
 size_t capacity_words_in_vs() const;
-size_t free_words_in_vs() const;
 bool initialize();
 // get space from the virtual space
 Metachunk* take_from_committed(size_t chunk_word_size);
 bool expand_by(size_t min_words, size_t preferred_words);
 // In preparation for deleting this node, remove all the chunks
 // in the node from any freelist.
 void purge(ChunkManager* chunk_manager);
+// If an allocation doesn't fit in the current node a new node is created.
+// Allocate chunks out of the remaining committed space in this node
+// to avoid wasting that memory.
+// This always adds up because all the chunk sizes are multiples of
+// the smallest chunk size.
+void retire(ChunkManager* chunk_manager);
 #ifdef ASSERT
 // Debug support
 void mangle();
 #endif
 // Get another virtual space and add it to the list.  This
 // is typically prompted by a failed attempt to allocate a chunk
 // and is typically followed by the allocation of a chunk.
 bool create_new_virtual_space(size_t vs_word_size);
+// Chunk up the unused committed space in the current
+// virtual space and add the chunks to the free list.
+void retire_current_virtual_space();
 public:
 VirtualSpaceList(size_t word_size);
 VirtualSpaceList(ReservedSpace rs);
 size_t free_bytes();
 };
 bool is_class() { return _mdtype == Metaspace::ClassType; }
 // Accessors
-size_t specialized_chunk_size() { return SpecializedChunk; }
+size_t specialized_chunk_size() { return (size_t) is_class() ? ClassSpecializedChunk : SpecializedChunk; }
-size_t small_chunk_size() { return (size_t) is_class() ? ClassSmallChunk : SmallChunk; }
+size_t small_chunk_size()       { return (size_t) is_class() ? ClassSmallChunk : SmallChunk; }
-size_t medium_chunk_size() { return (size_t) is_class() ? ClassMediumChunk : MediumChunk; }
+size_t medium_chunk_size()      { return (size_t) is_class() ? ClassMediumChunk : MediumChunk; }
-size_t medium_chunk_bunch() { return medium_chunk_size() * MediumChunkMultiple; }
+size_t medium_chunk_bunch()     { return medium_chunk_size() * MediumChunkMultiple; }
+size_t smallest_chunk_size()  { return specialized_chunk_size(); }
 size_t allocated_blocks_words() const { return _allocated_blocks_words; }
 size_t allocated_blocks_bytes() const { return _allocated_blocks_words * BytesPerWord; }
 size_t allocated_chunks_words() const { return _allocated_chunks_words; }
 size_t allocated_chunks_count() const { return _allocated_chunks_count; }
 }
 }
 #endif
 }
+void VirtualSpaceList::retire_current_virtual_space() {
+assert_lock_strong(SpaceManager::expand_lock());
+VirtualSpaceNode* vsn = current_virtual_space();
+ChunkManager* cm = is_class() ? Metaspace::chunk_manager_class() :
+Metaspace::chunk_manager_metadata();
+vsn->retire(cm);
+}
+void VirtualSpaceNode::retire(ChunkManager* chunk_manager) {
+for (int i = (int)MediumIndex; i >= (int)ZeroIndex; --i) {
+ChunkIndex index = (ChunkIndex)i;
+size_t chunk_size = chunk_manager->free_chunks(index)->size();
+while (free_words_in_vs() >= chunk_size) {
+DEBUG_ONLY(verify_container_count();)
+Metachunk* chunk = get_chunk_vs(chunk_size);
+assert(chunk != NULL, "allocation should have been successful");
+chunk_manager->return_chunks(index, chunk);
+chunk_manager->inc_free_chunks_total(chunk_size);
+DEBUG_ONLY(verify_container_count();)
+}
+}
+assert(free_words_in_vs() == 0, "should be empty now");
+}
 VirtualSpaceList::VirtualSpaceList(size_t word_size) :
 _is_class(false),
 _virtual_space_list(NULL),
 _current_virtual_space(NULL),
 _reserved_words(0),
 min_words,
 max_expansion_words);
 if (vs_expanded) {
 return true;
 }
+retire_current_virtual_space();
 // Get another virtual space.
 size_t grow_vs_words = MAX2((size_t)VirtualSpaceSize, preferred_words);
 grow_vs_words = align_size_up(grow_vs_words, Metaspace::reserve_alignment_words());
 }
 } else {
 chunk_word_size = medium_chunk_size();
 }
-// Might still need a humongous chunk.  Enforce an
+// Might still need a humongous chunk.  Enforce
-// eight word granularity to facilitate reuse (some
+// humongous allocations sizes to be aligned up to
-// wastage but better chance of reuse).
+// the smallest chunk size.
 size_t if_humongous_sized_chunk =
 align_size_up(word_size + Metachunk::overhead(),
-HumongousChunkGranularity);
+smallest_chunk_size());
 chunk_word_size =
 MAX2((size_t) chunk_word_size, if_humongous_sized_chunk);
 assert(!SpaceManager::is_humongous(word_size) ||
 chunk_word_size == if_humongous_sized_chunk,
 humongous_chunks,
 humongous_chunks->word_size());
 }
 assert(humongous_chunks->word_size() == (size_t)
 align_size_up(humongous_chunks->word_size(),
-HumongousChunkGranularity),
+smallest_chunk_size()),
 err_msg("Humongous chunk size is wrong: word size " SIZE_FORMAT
 " granularity %d",
-humongous_chunks->word_size(), HumongousChunkGranularity));
+humongous_chunks->word_size(), smallest_chunk_size()));
 Metachunk* next_humongous_chunks = humongous_chunks->next();
 humongous_chunks->container()->dec_container_count();
 chunk_manager()->humongous_dictionary()->return_chunk(humongous_chunks);
 humongous_chunks = next_humongous_chunks;
 }
 loader_data, word_size, mdtype);
 }
 }
 if (result == NULL) {
-report_metadata_oome(loader_data, word_size, mdtype, THREAD);
+report_metadata_oome(loader_data, word_size, mdtype, CHECK_NULL);
-// Will not reach here.
-return NULL;
 }
 // Zero initialize.
 Copy::fill_to_aligned_words((HeapWord*)result, word_size, 0);
 void TestMetaspaceAux_test() {
 TestMetaspaceAuxTest::test();
 }
+class TestVirtualSpaceNodeTest {
+static void chunk_up(size_t words_left, size_t& num_medium_chunks,
+size_t& num_small_chunks,
+size_t& num_specialized_chunks) {
+num_medium_chunks = words_left / MediumChunk;
+words_left = words_left % MediumChunk;
+num_small_chunks = words_left / SmallChunk;
+words_left = words_left % SmallChunk;
+// how many specialized chunks can we get?
+num_specialized_chunks = words_left / SpecializedChunk;
+assert(words_left % SpecializedChunk == 0, "should be nothing left");
+}
+public:
+static void test() {
+MutexLockerEx ml(SpaceManager::expand_lock(), Mutex::_no_safepoint_check_flag);
+const size_t vsn_test_size_words = MediumChunk  * 4;
+const size_t vsn_test_size_bytes = vsn_test_size_words * BytesPerWord;
+// The chunk sizes must be multiples of eachother, or this will fail
+STATIC_ASSERT(MediumChunk % SmallChunk == 0);
+STATIC_ASSERT(SmallChunk % SpecializedChunk == 0);
+{ // No committed memory in VSN
+ChunkManager cm(SpecializedChunk, SmallChunk, MediumChunk);
+VirtualSpaceNode vsn(vsn_test_size_bytes);
+vsn.initialize();
+vsn.retire(&cm);
+assert(cm.sum_free_chunks_count() == 0, "did not commit any memory in the VSN");
+}
+{ // All of VSN is committed, half is used by chunks
+ChunkManager cm(SpecializedChunk, SmallChunk, MediumChunk);
+VirtualSpaceNode vsn(vsn_test_size_bytes);
+vsn.initialize();
+vsn.expand_by(vsn_test_size_words, vsn_test_size_words);
+vsn.get_chunk_vs(MediumChunk);
+vsn.get_chunk_vs(MediumChunk);
+vsn.retire(&cm);
+assert(cm.sum_free_chunks_count() == 2, "should have been memory left for 2 medium chunks");
+assert(cm.sum_free_chunks() == 2*MediumChunk, "sizes should add up");
+}
+{ // 4 pages of VSN is committed, some is used by chunks
+ChunkManager cm(SpecializedChunk, SmallChunk, MediumChunk);
+VirtualSpaceNode vsn(vsn_test_size_bytes);
+const size_t page_chunks = 4 * (size_t)os::vm_page_size() / BytesPerWord;
+assert(page_chunks < MediumChunk, "Test expects medium chunks to be at least 4*page_size");
+vsn.initialize();
+vsn.expand_by(page_chunks, page_chunks);
+vsn.get_chunk_vs(SmallChunk);
+vsn.get_chunk_vs(SpecializedChunk);
+vsn.retire(&cm);
+// committed - used = words left to retire
+const size_t words_left = page_chunks - SmallChunk - SpecializedChunk;
+size_t num_medium_chunks, num_small_chunks, num_spec_chunks;
+chunk_up(words_left, num_medium_chunks, num_small_chunks, num_spec_chunks);
+assert(num_medium_chunks == 0, "should not get any medium chunks");
+assert(cm.sum_free_chunks_count() == (num_small_chunks + num_spec_chunks), "should be space for 3 chunks");
+assert(cm.sum_free_chunks() == words_left, "sizes should add up");
+}
+{ // Half of VSN is committed, a humongous chunk is used
+ChunkManager cm(SpecializedChunk, SmallChunk, MediumChunk);
+VirtualSpaceNode vsn(vsn_test_size_bytes);
+vsn.initialize();
+vsn.expand_by(MediumChunk * 2, MediumChunk * 2);
+vsn.get_chunk_vs(MediumChunk + SpecializedChunk); // Humongous chunks will be aligned up to MediumChunk + SpecializedChunk
+vsn.retire(&cm);
+const size_t words_left = MediumChunk * 2 - (MediumChunk + SpecializedChunk);
+size_t num_medium_chunks, num_small_chunks, num_spec_chunks;
+chunk_up(words_left, num_medium_chunks, num_small_chunks, num_spec_chunks);
+assert(num_medium_chunks == 0, "should not get any medium chunks");
+assert(cm.sum_free_chunks_count() == (num_small_chunks + num_spec_chunks), "should be space for 3 chunks");
+assert(cm.sum_free_chunks() == words_left, "sizes should add up");
+}
+}
+};
+void TestVirtualSpaceNode_test() {
+TestVirtualSpaceNodeTest::test();
+}
 #endif

changeset 21189	e851a0a007ce
parent 21188	d053e4e8f901
parent 21113	65e0eb464169
child 21518	067dd7967128
child 21562	f3f6ea8474d0