--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/memory/metaspace/metachunk.hpp Mon May 21 11:33:59 2018 +0200
@@ -0,0 +1,173 @@
+/*
+ * Copyright (c) 2012, 2018, 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
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ *
+ */
+#ifndef SHARE_VM_MEMORY_METACHUNK_HPP
+#define SHARE_VM_MEMORY_METACHUNK_HPP
+
+#include "memory/metaspace/metabase.hpp"
+#include "memory/metaspace/metaspaceCommon.hpp"
+#include "utilities/debug.hpp"
+#include "utilities/globalDefinitions.hpp"
+
+class MetachunkTest;
+
+namespace metaspace {
+
+class VirtualSpaceNode;
+
+// Metachunk - Quantum of allocation from a Virtualspace
+// Metachunks are reused (when freed are put on a global freelist) and
+// have no permanent association to a SpaceManager.
+
+// +--------------+ <- end --+ --+
+// | | | |
+// | | | free |
+// | | | |
+// | | | | size | capacity
+// | | | |
+// | | <- top -- + |
+// | | | |
+// | | | used |
+// | | | |
+// | | | |
+// +--------------+ <- bottom --+ --+
+
+enum ChunkOrigin {
+ // Chunk normally born (via take_from_committed)
+ origin_normal = 1,
+ // Chunk was born as padding chunk
+ origin_pad = 2,
+ // Chunk was born as leftover chunk in VirtualSpaceNode::retire
+ origin_leftover = 3,
+ // Chunk was born as result of a merge of smaller chunks
+ origin_merge = 4,
+ // Chunk was born as result of a split of a larger chunk
+ origin_split = 5,
+
+ origin_minimum = origin_normal,
+ origin_maximum = origin_split,
+ origins_count = origin_maximum + 1
+};
+
+inline bool is_valid_chunkorigin(ChunkOrigin origin) {
+ return origin == origin_normal ||
+ origin == origin_pad ||
+ origin == origin_leftover ||
+ origin == origin_merge ||
+ origin == origin_split;
+}
+
+class Metachunk : public Metabase<Metachunk> {
+
+ friend class ::MetachunkTest;
+
+ // The VirtualSpaceNode containing this chunk.
+ VirtualSpaceNode* const _container;
+
+ // Current allocation top.
+ MetaWord* _top;
+
+ // A 32bit sentinel for debugging purposes.
+ enum { CHUNK_SENTINEL = 0x4d4554EF, // "MET"
+ CHUNK_SENTINEL_INVALID = 0xFEEEEEEF
+ };
+
+ uint32_t _sentinel;
+
+ const ChunkIndex _chunk_type;
+ const bool _is_class;
+ // Whether the chunk is free (in freelist) or in use by some class loader.
+ bool _is_tagged_free;
+
+ ChunkOrigin _origin;
+ int _use_count;
+
+ MetaWord* initial_top() const { return (MetaWord*)this + overhead(); }
+ MetaWord* top() const { return _top; }
+
+ public:
+ // Metachunks are allocated out of a MetadataVirtualSpace and
+ // and use some of its space to describe itself (plus alignment
+ // considerations). Metadata is allocated in the rest of the chunk.
+ // This size is the overhead of maintaining the Metachunk within
+ // the space.
+
+ // Alignment of each allocation in the chunks.
+ static size_t object_alignment();
+
+ // Size of the Metachunk header, in words, including alignment.
+ static size_t overhead();
+
+ Metachunk(ChunkIndex chunktype, bool is_class, size_t word_size, VirtualSpaceNode* container);
+
+ MetaWord* allocate(size_t word_size);
+
+ VirtualSpaceNode* container() const { return _container; }
+
+ MetaWord* bottom() const { return (MetaWord*) this; }
+
+ // Reset top to bottom so chunk can be reused.
+ void reset_empty() { _top = initial_top(); clear_next(); clear_prev(); }
+ bool is_empty() { return _top == initial_top(); }
+
+ // used (has been allocated)
+ // free (available for future allocations)
+ size_t word_size() const { return size(); }
+ size_t used_word_size() const;
+ size_t free_word_size() const;
+
+ bool is_tagged_free() { return _is_tagged_free; }
+ void set_is_tagged_free(bool v) { _is_tagged_free = v; }
+
+ bool contains(const void* ptr) { return bottom() <= ptr && ptr < _top; }
+
+ void print_on(outputStream* st) const;
+
+ bool is_valid_sentinel() const { return _sentinel == CHUNK_SENTINEL; }
+ void remove_sentinel() { _sentinel = CHUNK_SENTINEL_INVALID; }
+
+ int get_use_count() const { return _use_count; }
+ void inc_use_count() { _use_count ++; }
+
+ ChunkOrigin get_origin() const { return _origin; }
+ void set_origin(ChunkOrigin orig) { _origin = orig; }
+
+ ChunkIndex get_chunk_type() const { return _chunk_type; }
+ bool is_class() const { return _is_class; }
+
+ DEBUG_ONLY(void mangle(juint word_value);)
+ DEBUG_ONLY(void verify() const;)
+
+};
+
+
+// Helper function that does a bunch of checks for a chunk.
+DEBUG_ONLY(void do_verify_chunk(Metachunk* chunk);)
+
+// Given a Metachunk, update its in-use information (both in the
+// chunk and the occupancy map).
+void do_update_in_use_info_for_chunk(Metachunk* chunk, bool inuse);
+
+} // namespace metaspace
+
+#endif // SHARE_VM_MEMORY_METACHUNK_HPP