hotspot/src/share/vm/memory/metaspace.hpp - platform/libcore - Git at Google

 /*
  * Copyright (c) 2011, 2012, 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_METASPACE_HPP
 #define SHARE_VM_MEMORY_METASPACE_HPP

 #include "memory/allocation.hpp"
 #include "memory/memRegion.hpp"
 #include "runtime/virtualspace.hpp"
 #include "utilities/exceptions.hpp"

 // Metaspace
 //
 // Metaspaces are Arenas for the VM's metadata.
 // They are allocated one per class loader object, and one for the null
 // bootstrap class loader
 // Eventually for bootstrap loader we'll have a read-only section and read-write
 // to write for DumpSharedSpaces and read for UseSharedSpaces
 //
 //    block X ---+       +-------------------+
 //               |       |  Virtualspace     |
 //               |       |                   |
 //               |       |                   |
 //               |       |-------------------|
 //               |       || Chunk            |
 //               |       ||                  |
 //               |       ||----------        |
 //               +------>||| block 0 |       |
 //                       ||----------        |
 //                       ||| block 1 |       |
 //                       ||----------        |
 //                       ||                  |
 //                       |-------------------|
 //                       |                   |
 //                       |                   |
 //                       +-------------------+
 //

 class ClassLoaderData;
 class Metablock;
 class MetaWord;
 class Mutex;
 class outputStream;
 class SpaceManager;

 // Metaspaces each have a  SpaceManager and allocations
 // are done by the SpaceManager.  Allocations are done
 // out of the current Metachunk.  When the current Metachunk
 // is exhausted, the SpaceManager gets a new one from
 // the current VirtualSpace.  When the VirtualSpace is exhausted
 // the SpaceManager gets a new one.  The SpaceManager
 // also manages freelists of available Chunks.
 //
 // Currently the space manager maintains the list of
 // virtual spaces and the list of chunks in use.  Its
 // allocate() method returns a block for use as a
 // quantum of metadata.

 class VirtualSpaceList;

 class Metaspace : public CHeapObj<mtClass> {
   friend class VMStructs;
   friend class SpaceManager;
   friend class VM_CollectForMetadataAllocation;
   friend class MetaspaceGC;
   friend class MetaspaceAux;

  public:
   enum MetadataType {ClassType, NonClassType};
   enum MetaspaceType {
     StandardMetaspaceType,
     BootMetaspaceType,
     ROMetaspaceType,
     ReadWriteMetaspaceType,
     AnonymousMetaspaceType,
     ReflectionMetaspaceType
   };

  private:
   void initialize(Mutex* lock, MetaspaceType type);

   // Align up the word size to the allocation word size
   static size_t align_word_size_up(size_t);

   static size_t _first_chunk_word_size;
   static size_t _first_class_chunk_word_size;

   SpaceManager* _vsm;
   SpaceManager* vsm() const { return _vsm; }

   SpaceManager* _class_vsm;
   SpaceManager* class_vsm() const { return _class_vsm; }

   MetaWord* allocate(size_t word_size, MetadataType mdtype);

   // Virtual Space lists for both classes and other metadata
   static VirtualSpaceList* _space_list;
   static VirtualSpaceList* _class_space_list;

   static VirtualSpaceList* space_list()       { return _space_list; }
   static VirtualSpaceList* class_space_list() { return _class_space_list; }

  public:

   Metaspace(Mutex* lock, MetaspaceType type);
   ~Metaspace();

   // Initialize globals for Metaspace
   static void global_initialize();
   static void initialize_class_space(ReservedSpace rs);

   static size_t first_chunk_word_size() { return _first_chunk_word_size; }
   static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }

   char*  bottom() const;
   size_t used_words(MetadataType mdtype) const;
   size_t free_words(MetadataType mdtype) const;
   size_t capacity_words(MetadataType mdtype) const;
   size_t waste_words(MetadataType mdtype) const;

   static Metablock* allocate(ClassLoaderData* loader_data, size_t size,
                             bool read_only, MetadataType mdtype, TRAPS);
   void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);

   MetaWord* expand_and_allocate(size_t size,
                                 MetadataType mdtype);

   static bool is_initialized() { return _class_space_list != NULL; }

   static bool contains(const void *ptr);
   void dump(outputStream* const out) const;

   void print_on(outputStream* st) const;
   // Debugging support
   void verify();
 };

 class MetaspaceAux : AllStatic {

   // Statistics for class space and data space in metaspace.
   static size_t used_in_bytes(Metaspace::MetadataType mdtype);
   static size_t free_in_bytes(Metaspace::MetadataType mdtype);
   static size_t capacity_in_bytes(Metaspace::MetadataType mdtype);
   static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);

   static size_t free_chunks_total(Metaspace::MetadataType mdtype);
   static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);

  public:
   // Total of space allocated to metadata in all Metaspaces
   static size_t used_in_bytes() {
     return used_in_bytes(Metaspace::ClassType) +
            used_in_bytes(Metaspace::NonClassType);
   }

   // Total of available space in all Metaspaces
   // Total of capacity allocated to all Metaspaces.  This includes
   // space in Metachunks not yet allocated and in the Metachunk
   // freelist.
   static size_t capacity_in_bytes() {
     return capacity_in_bytes(Metaspace::ClassType) +
            capacity_in_bytes(Metaspace::NonClassType);
   }

   // Total space reserved in all Metaspaces
   static size_t reserved_in_bytes() {
     return reserved_in_bytes(Metaspace::ClassType) +
            reserved_in_bytes(Metaspace::NonClassType);
   }

   static size_t min_chunk_size();

   // Print change in used metadata.
   static void print_metaspace_change(size_t prev_metadata_used);
   static void print_on(outputStream * out);
   static void print_on(outputStream * out, Metaspace::MetadataType mdtype);

   static void print_waste(outputStream* out);
   static void dump(outputStream* out);
   static void verify_free_chunks();
 };

 // Metaspace are deallocated when their class loader are GC'ed.
 // This class implements a policy for inducing GC's to recover
 // Metaspaces.

 class MetaspaceGC : AllStatic {

   // The current high-water-mark for inducing a GC.  When
   // the capacity of all space in the virtual lists reaches this value,
   // a GC is induced and the value is increased.  This should be changed
   // to the space actually used for allocations to avoid affects of
   // fragmentation losses to partially used chunks.  Size is in words.
   static size_t _capacity_until_GC;

   // After a GC is done any allocation that fails should try to expand
   // the capacity of the Metaspaces.  This flag is set during attempts
   // to allocate in the VMGCOperation that does the GC.
   static bool _expand_after_GC;

   // For a CMS collection, signal that a concurrent collection should
   // be started.
   static bool _should_concurrent_collect;

   static uint _shrink_factor;

   static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }

   static size_t shrink_factor() { return _shrink_factor; }
   void set_shrink_factor(uint v) { _shrink_factor = v; }

  public:

   static size_t capacity_until_GC() { return _capacity_until_GC; }
   static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; }
   static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
   static void dec_capacity_until_GC(size_t v) {
     _capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
   }
   static bool expand_after_GC()           { return _expand_after_GC; }
   static void set_expand_after_GC(bool v) { _expand_after_GC = v; }

   static bool should_concurrent_collect() { return _should_concurrent_collect; }
   static void set_should_concurrent_collect(bool v) {
     _should_concurrent_collect = v;
   }

   // The amount to increase the high-water-mark (_capacity_until_GC)
   static size_t delta_capacity_until_GC(size_t word_size);

   // It is expected that this will be called when the current capacity
   // has been used and a GC should be considered.
   static bool should_expand(VirtualSpaceList* vsl, size_t word_size);

   // Calculate the new high-water mark at which to induce
   // a GC.
   static void compute_new_size();
 };

 #endif // SHARE_VM_MEMORY_METASPACE_HPP
	/*
	* Copyright (c) 2011, 2012, 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_METASPACE_HPP
	#define SHARE_VM_MEMORY_METASPACE_HPP

	#include "memory/allocation.hpp"
	#include "memory/memRegion.hpp"
	#include "runtime/virtualspace.hpp"
	#include "utilities/exceptions.hpp"

	// Metaspace
	//
	// Metaspaces are Arenas for the VM's metadata.
	// They are allocated one per class loader object, and one for the null
	// bootstrap class loader
	// Eventually for bootstrap loader we'll have a read-only section and read-write
	// to write for DumpSharedSpaces and read for UseSharedSpaces
	//
	// block X ---+ +-------------------+
	// \| \| Virtualspace \|
	// \| \| \|
	// \| \| \|
	// \| \|-------------------\|
	// \| \|\| Chunk \|
	// \| \|\| \|
	// \| \|\|---------- \|
	// +------>\|\|\| block 0 \| \|
	// \|\|---------- \|
	// \|\|\| block 1 \| \|
	// \|\|---------- \|
	// \|\| \|
	// \|-------------------\|
	// \| \|
	// \| \|
	// +-------------------+
	//

	class ClassLoaderData;
	class Metablock;
	class MetaWord;
	class Mutex;
	class outputStream;
	class SpaceManager;

	// Metaspaces each have a SpaceManager and allocations
	// are done by the SpaceManager. Allocations are done
	// out of the current Metachunk. When the current Metachunk
	// is exhausted, the SpaceManager gets a new one from
	// the current VirtualSpace. When the VirtualSpace is exhausted
	// the SpaceManager gets a new one. The SpaceManager
	// also manages freelists of available Chunks.
	//
	// Currently the space manager maintains the list of
	// virtual spaces and the list of chunks in use. Its
	// allocate() method returns a block for use as a
	// quantum of metadata.

	class VirtualSpaceList;

	class Metaspace : public CHeapObj<mtClass> {
	friend class VMStructs;
	friend class SpaceManager;
	friend class VM_CollectForMetadataAllocation;
	friend class MetaspaceGC;
	friend class MetaspaceAux;

	public:
	enum MetadataType {ClassType, NonClassType};
	enum MetaspaceType {
	StandardMetaspaceType,
	BootMetaspaceType,
	ROMetaspaceType,
	ReadWriteMetaspaceType,
	AnonymousMetaspaceType,
	ReflectionMetaspaceType
	};

	private:
	void initialize(Mutex* lock, MetaspaceType type);

	// Align up the word size to the allocation word size
	static size_t align_word_size_up(size_t);

	static size_t _first_chunk_word_size;
	static size_t _first_class_chunk_word_size;

	SpaceManager* _vsm;
	SpaceManager* vsm() const { return _vsm; }

	SpaceManager* _class_vsm;
	SpaceManager* class_vsm() const { return _class_vsm; }

	MetaWord* allocate(size_t word_size, MetadataType mdtype);

	// Virtual Space lists for both classes and other metadata
	static VirtualSpaceList* _space_list;
	static VirtualSpaceList* _class_space_list;

	static VirtualSpaceList* space_list() { return _space_list; }
	static VirtualSpaceList* class_space_list() { return _class_space_list; }

	public:

	Metaspace(Mutex* lock, MetaspaceType type);
	~Metaspace();

	// Initialize globals for Metaspace
	static void global_initialize();
	static void initialize_class_space(ReservedSpace rs);

	static size_t first_chunk_word_size() { return _first_chunk_word_size; }
	static size_t first_class_chunk_word_size() { return _first_class_chunk_word_size; }

	char* bottom() const;
	size_t used_words(MetadataType mdtype) const;
	size_t free_words(MetadataType mdtype) const;
	size_t capacity_words(MetadataType mdtype) const;
	size_t waste_words(MetadataType mdtype) const;

	static Metablock* allocate(ClassLoaderData* loader_data, size_t size,
	bool read_only, MetadataType mdtype, TRAPS);
	void deallocate(MetaWord* ptr, size_t byte_size, bool is_class);

	MetaWord* expand_and_allocate(size_t size,
	MetadataType mdtype);

	static bool is_initialized() { return _class_space_list != NULL; }

	static bool contains(const void *ptr);
	void dump(outputStream* const out) const;

	void print_on(outputStream* st) const;
	// Debugging support
	void verify();
	};

	class MetaspaceAux : AllStatic {

	// Statistics for class space and data space in metaspace.
	static size_t used_in_bytes(Metaspace::MetadataType mdtype);
	static size_t free_in_bytes(Metaspace::MetadataType mdtype);
	static size_t capacity_in_bytes(Metaspace::MetadataType mdtype);
	static size_t reserved_in_bytes(Metaspace::MetadataType mdtype);

	static size_t free_chunks_total(Metaspace::MetadataType mdtype);
	static size_t free_chunks_total_in_bytes(Metaspace::MetadataType mdtype);

	public:
	// Total of space allocated to metadata in all Metaspaces
	static size_t used_in_bytes() {
	return used_in_bytes(Metaspace::ClassType) +
	used_in_bytes(Metaspace::NonClassType);
	}

	// Total of available space in all Metaspaces
	// Total of capacity allocated to all Metaspaces. This includes
	// space in Metachunks not yet allocated and in the Metachunk
	// freelist.
	static size_t capacity_in_bytes() {
	return capacity_in_bytes(Metaspace::ClassType) +
	capacity_in_bytes(Metaspace::NonClassType);
	}

	// Total space reserved in all Metaspaces
	static size_t reserved_in_bytes() {
	return reserved_in_bytes(Metaspace::ClassType) +
	reserved_in_bytes(Metaspace::NonClassType);
	}

	static size_t min_chunk_size();

	// Print change in used metadata.
	static void print_metaspace_change(size_t prev_metadata_used);
	static void print_on(outputStream * out);
	static void print_on(outputStream * out, Metaspace::MetadataType mdtype);

	static void print_waste(outputStream* out);
	static void dump(outputStream* out);
	static void verify_free_chunks();
	};

	// Metaspace are deallocated when their class loader are GC'ed.
	// This class implements a policy for inducing GC's to recover
	// Metaspaces.

	class MetaspaceGC : AllStatic {

	// The current high-water-mark for inducing a GC. When
	// the capacity of all space in the virtual lists reaches this value,
	// a GC is induced and the value is increased. This should be changed
	// to the space actually used for allocations to avoid affects of
	// fragmentation losses to partially used chunks. Size is in words.
	static size_t _capacity_until_GC;

	// After a GC is done any allocation that fails should try to expand
	// the capacity of the Metaspaces. This flag is set during attempts
	// to allocate in the VMGCOperation that does the GC.
	static bool _expand_after_GC;

	// For a CMS collection, signal that a concurrent collection should
	// be started.
	static bool _should_concurrent_collect;

	static uint _shrink_factor;

	static void set_capacity_until_GC(size_t v) { _capacity_until_GC = v; }

	static size_t shrink_factor() { return _shrink_factor; }
	void set_shrink_factor(uint v) { _shrink_factor = v; }

	public:

	static size_t capacity_until_GC() { return _capacity_until_GC; }
	static size_t capacity_until_GC_in_bytes() { return _capacity_until_GC * BytesPerWord; }
	static void inc_capacity_until_GC(size_t v) { _capacity_until_GC += v; }
	static void dec_capacity_until_GC(size_t v) {
	_capacity_until_GC = _capacity_until_GC > v ? _capacity_until_GC - v : 0;
	}
	static bool expand_after_GC() { return _expand_after_GC; }
	static void set_expand_after_GC(bool v) { _expand_after_GC = v; }

	static bool should_concurrent_collect() { return _should_concurrent_collect; }
	static void set_should_concurrent_collect(bool v) {
	_should_concurrent_collect = v;
	}

	// The amount to increase the high-water-mark (_capacity_until_GC)
	static size_t delta_capacity_until_GC(size_t word_size);

	// It is expected that this will be called when the current capacity
	// has been used and a GC should be considered.
	static bool should_expand(VirtualSpaceList* vsl, size_t word_size);

	// Calculate the new high-water mark at which to induce
	// a GC.
	static void compute_new_size();
	};

	#endif // SHARE_VM_MEMORY_METASPACE_HPP