# HG changeset patch # User stefank # Date 1381840131 -7200 # Node ID bdfbb1fb19cab10cafe65271298c6749e044b87b # Parent f167269247340824096c0bc2a5db4f854fd2ddd5 8026391: The Metachunk header wastes memory Reviewed-by: coleenp, jmasa diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/binaryTreeDictionary.cpp --- a/src/share/vm/memory/binaryTreeDictionary.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/binaryTreeDictionary.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -28,7 +28,6 @@ #include "memory/binaryTreeDictionary.hpp" #include "memory/freeList.hpp" #include "memory/freeBlockDictionary.hpp" -#include "memory/metablock.hpp" #include "memory/metachunk.hpp" #include "runtime/globals.hpp" #include "utilities/ostream.hpp" diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/freeBlockDictionary.cpp --- a/src/share/vm/memory/freeBlockDictionary.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/freeBlockDictionary.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -28,7 +28,6 @@ #include "gc_implementation/concurrentMarkSweep/freeChunk.hpp" #endif // INCLUDE_ALL_GCS #include "memory/freeBlockDictionary.hpp" -#include "memory/metablock.hpp" #include "memory/metachunk.hpp" #include "runtime/thread.inline.hpp" #include "utilities/macros.hpp" diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/freeList.cpp --- a/src/share/vm/memory/freeList.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/freeList.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -25,7 +25,6 @@ #include "precompiled.hpp" #include "memory/freeBlockDictionary.hpp" #include "memory/freeList.hpp" -#include "memory/metablock.hpp" #include "memory/metachunk.hpp" #include "memory/sharedHeap.hpp" #include "runtime/globals.hpp" diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/metablock.cpp --- a/src/share/vm/memory/metablock.cpp Tue Oct 15 07:10:09 2013 -0700 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,68 +0,0 @@ -/* - * Copyright (c) 2012, 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 - * 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. - * - */ - -#include "precompiled.hpp" -#include "memory/allocation.hpp" -#include "memory/metablock.hpp" -#include "utilities/copy.hpp" -#include "utilities/debug.hpp" - -// Blocks of space for metadata are allocated out of Metachunks. -// -// Metachunk are allocated out of MetadataVirtualspaces and once -// allocated there is no explicit link between a Metachunk and -// the MetadataVirtualspaces from which it was allocated. -// -// Each SpaceManager maintains a -// list of the chunks it is using and the current chunk. The current -// chunk is the chunk from which allocations are done. Space freed in -// a chunk is placed on the free list of blocks (BlockFreelist) and -// reused from there. -// -// Future modification -// -// The Metachunk can conceivable be replaced by the Chunk in -// allocation.hpp. Note that the latter Chunk is the space for -// allocation (allocations from the chunk are out of the space in -// the Chunk after the header for the Chunk) where as Metachunks -// point to space in a VirtualSpace. To replace Metachunks with -// Chunks, change Chunks so that they can be allocated out of a VirtualSpace. -size_t Metablock::_min_block_byte_size = sizeof(Metablock); - -// New blocks returned by the Metaspace are zero initialized. -// We should fix the constructors to not assume this instead. -Metablock* Metablock::initialize(MetaWord* p, size_t word_size) { - if (p == NULL) { - return NULL; - } - - Metablock* result = (Metablock*) p; - - // Clear the memory - Copy::fill_to_aligned_words((HeapWord*)result, word_size); -#ifdef ASSERT - result->set_word_size(word_size); -#endif - return result; -} diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/metablock.hpp --- a/src/share/vm/memory/metablock.hpp Tue Oct 15 07:10:09 2013 -0700 +++ /dev/null Thu Jan 01 00:00:00 1970 +0000 @@ -1,101 +0,0 @@ -/* - * Copyright (c) 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_METABLOCK_HPP -#define SHARE_VM_MEMORY_METABLOCK_HPP - -// Metablock are the unit of allocation from a Chunk. It is initialized -// with the size of the requested allocation. That size is overwritten -// once the allocation returns. -// -// A Metablock may be reused by its SpaceManager but are never moved between -// SpaceManagers. There is no explicit link to the Metachunk -// from which it was allocated. Metablock may be deallocated and -// put on a freelist but the space is never freed, rather -// the Metachunk it is a part of will be deallocated when it's -// associated class loader is collected. - -class Metablock VALUE_OBJ_CLASS_SPEC { - friend class VMStructs; - private: - // Used to align the allocation (see below). - union block_t { - void* _data[3]; - struct header_t { - size_t _word_size; - Metablock* _next; - Metablock* _prev; - } _header; - } _block; - static size_t _min_block_byte_size; - - typedef union block_t Block; - typedef struct header_t Header; - const Block* block() const { return &_block; } - const Block::header_t* header() const { return &(block()->_header); } - public: - - static Metablock* initialize(MetaWord* p, size_t word_size); - - // This places the body of the block at a 2 word boundary - // because every block starts on a 2 word boundary. Work out - // how to make the body on a 2 word boundary if the block - // starts on a arbitrary boundary. JJJ - - size_t word_size() const { return header()->_word_size; } - void set_word_size(size_t v) { _block._header._word_size = v; } - size_t size() const volatile { return _block._header._word_size; } - void set_size(size_t v) { _block._header._word_size = v; } - Metablock* next() const { return header()->_next; } - void set_next(Metablock* v) { _block._header._next = v; } - Metablock* prev() const { return header()->_prev; } - void set_prev(Metablock* v) { _block._header._prev = v; } - - static size_t min_block_byte_size() { return _min_block_byte_size; } - - bool is_free() { return header()->_word_size != 0; } - void clear_next() { set_next(NULL); } - void link_prev(Metablock* ptr) { set_prev(ptr); } - uintptr_t* end() { return ((uintptr_t*) this) + size(); } - bool cantCoalesce() const { return false; } - void link_next(Metablock* ptr) { set_next(ptr); } - void link_after(Metablock* ptr){ - link_next(ptr); - if (ptr != NULL) ptr->link_prev(this); - } - - // Should not be needed in a free list of Metablocks - void markNotFree() { ShouldNotReachHere(); } - - // Debug support -#ifdef ASSERT - void* prev_addr() const { return (void*)&_block._header._prev; } - void* next_addr() const { return (void*)&_block._header._next; } - void* size_addr() const { return (void*)&_block._header._word_size; } -#endif - bool verify_chunk_in_free_list(Metablock* tc) const { return true; } - bool verify_par_locked() { return true; } - - void assert_is_mangled() const {/* Don't check "\*/} -}; -#endif // SHARE_VM_MEMORY_METABLOCK_HPP diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/metachunk.cpp --- a/src/share/vm/memory/metachunk.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/metachunk.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2012, 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 @@ -29,42 +29,32 @@ #include "utilities/debug.hpp" class VirtualSpaceNode; -// -// Future modification -// -// The Metachunk can conceivable be replaced by the Chunk in -// allocation.hpp. Note that the latter Chunk is the space for -// allocation (allocations from the chunk are out of the space in -// the Chunk after the header for the Chunk) where as Metachunks -// point to space in a VirtualSpace. To replace Metachunks with -// Chunks, change Chunks so that they can be allocated out of a VirtualSpace. const size_t metadata_chunk_initialize = 0xf7f7f7f7; -size_t Metachunk::_overhead = - Chunk::aligned_overhead_size(sizeof(Metachunk)) / BytesPerWord; +size_t Metachunk::object_alignment() { + return ARENA_AMALLOC_ALIGNMENT; +} + +size_t Metachunk::overhead() { + return align_size_up(sizeof(Metachunk), object_alignment()) / BytesPerWord; +} // Metachunk methods Metachunk::Metachunk(size_t word_size, - VirtualSpaceNode* container) : - _word_size(word_size), - _bottom(NULL), - _end(NULL), + VirtualSpaceNode* container) + : Metabase(word_size), _top(NULL), - _next(NULL), - _prev(NULL), _container(container) { - _bottom = (MetaWord*)this; - _top = (MetaWord*)this + _overhead; - _end = (MetaWord*)this + word_size; + _top = initial_top(); #ifdef ASSERT - set_is_free(false); + set_is_tagged_free(false); size_t data_word_size = pointer_delta(end(), - top(), + _top, sizeof(MetaWord)); - Copy::fill_to_words((HeapWord*) top(), + Copy::fill_to_words((HeapWord*)_top, data_word_size, metadata_chunk_initialize); #endif @@ -82,22 +72,18 @@ // _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)); + return pointer_delta(_top, bottom(), sizeof(MetaWord)); } size_t Metachunk::free_word_size() const { - return pointer_delta(_end, _top, sizeof(MetaWord)); -} - -size_t Metachunk::capacity_word_size() const { - return pointer_delta(_end, _bottom, sizeof(MetaWord)); + 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, - bottom(), top(), end(), word_size()); + bottom(), _top, end(), word_size()); if (Verbose) { st->print_cr(" used " SIZE_FORMAT " free " SIZE_FORMAT, used_word_size(), free_word_size()); @@ -109,8 +95,8 @@ // Mangle the payload of the chunk and not the links that // maintain list of chunks. HeapWord* start = (HeapWord*)(bottom() + overhead()); - size_t word_size = capacity_word_size() - overhead(); - Copy::fill_to_words(start, word_size, metadata_chunk_initialize); + size_t size = word_size() - overhead(); + Copy::fill_to_words(start, size, metadata_chunk_initialize); } #endif // PRODUCT @@ -118,9 +104,68 @@ #ifdef ASSERT // Cannot walk through the blocks unless the blocks have // headers with sizes. - assert(_bottom <= _top && - _top <= _end, + assert(bottom() <= _top && + _top <= (MetaWord*)end(), "Chunk has been smashed"); #endif return; } + +/////////////// Unit tests /////////////// + +#ifndef PRODUCT + +class TestMetachunk { + public: + static void test() { + size_t size = 2 * 1024 * 1024; + void* memory = malloc(size); + assert(memory != NULL, "Failed to malloc 2MB"); + + Metachunk* metachunk = ::new (memory) Metachunk(size / BytesPerWord, NULL); + + assert(metachunk->bottom() == (MetaWord*)metachunk, "assert"); + assert(metachunk->end() == (uintptr_t*)metachunk + metachunk->size(), "assert"); + + // Check sizes + assert(metachunk->size() == metachunk->word_size(), "assert"); + assert(metachunk->word_size() == pointer_delta(metachunk->end(), metachunk->bottom(), + sizeof(MetaWord*)), "assert"); + + // Check usage + assert(metachunk->used_word_size() == metachunk->overhead(), "assert"); + assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); + assert(metachunk->top() == metachunk->initial_top(), "assert"); + assert(metachunk->is_empty(), "assert"); + + // Allocate + size_t alloc_size = 64; // Words + assert(is_size_aligned(alloc_size, Metachunk::object_alignment()), "assert"); + + MetaWord* mem = metachunk->allocate(alloc_size); + + // Check post alloc + assert(mem == metachunk->initial_top(), "assert"); + assert(mem + alloc_size == metachunk->top(), "assert"); + assert(metachunk->used_word_size() == metachunk->overhead() + alloc_size, "assert"); + assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); + assert(!metachunk->is_empty(), "assert"); + + // Clear chunk + metachunk->reset_empty(); + + // Check post clear + assert(metachunk->used_word_size() == metachunk->overhead(), "assert"); + assert(metachunk->free_word_size() == metachunk->word_size() - metachunk->used_word_size(), "assert"); + assert(metachunk->top() == metachunk->initial_top(), "assert"); + assert(metachunk->is_empty(), "assert"); + + free(memory); + } +}; + +void TestMetachunk_test() { + TestMetachunk::test(); +} + +#endif diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/metachunk.hpp --- a/src/share/vm/memory/metachunk.hpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/metachunk.hpp Tue Oct 15 14:28:51 2013 +0200 @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012, Oracle and/or its affiliates. All rights reserved. + * Copyright (c) 2012, 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 @@ -24,89 +24,44 @@ #ifndef SHARE_VM_MEMORY_METACHUNK_HPP #define SHARE_VM_MEMORY_METACHUNK_HPP -// 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 | -// | | | | -// | | | | capacity -// | | | | -// | | <- top --+ | -// | | ---+ | -// | | | used | -// | | | | -// | | | | -// +--------------+ <- bottom ---+ ---+ +#include "memory/allocation.hpp" +#include "utilities/debug.hpp" +#include "utilities/globalDefinitions.hpp" class VirtualSpaceNode; -class Metachunk VALUE_OBJ_CLASS_SPEC { - // link to support lists of chunks - Metachunk* _next; - Metachunk* _prev; - VirtualSpaceNode* _container; - - MetaWord* _bottom; - MetaWord* _end; - MetaWord* _top; +// Super class of Metablock and Metachunk to allow them to +// be put on the FreeList and in the BinaryTreeDictionary. +template +class Metabase VALUE_OBJ_CLASS_SPEC { size_t _word_size; - // Used in a guarantee() so included in the Product builds - // even through it is only for debugging. - bool _is_free; + T* _next; + T* _prev; - // 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. - static size_t _overhead; + protected: + Metabase(size_t word_size) : _word_size(word_size), _next(NULL), _prev(NULL) {} public: - Metachunk(size_t word_size , VirtualSpaceNode* container); - - // Used to add a Metachunk to a list of Metachunks - void set_next(Metachunk* v) { _next = v; assert(v != this, "Boom");} - void set_prev(Metachunk* v) { _prev = v; assert(v != this, "Boom");} - void set_container(VirtualSpaceNode* v) { _container = v; } - - MetaWord* allocate(size_t word_size); + T* next() const { return _next; } + T* prev() const { return _prev; } + void set_next(T* v) { _next = v; assert(v != this, "Boom");} + void set_prev(T* v) { _prev = v; assert(v != this, "Boom");} + void clear_next() { set_next(NULL); } + void clear_prev() { set_prev(NULL); } - // Accessors - Metachunk* next() const { return _next; } - Metachunk* prev() const { return _prev; } - VirtualSpaceNode* container() const { return _container; } - MetaWord* bottom() const { return _bottom; } - MetaWord* end() const { return _end; } - MetaWord* top() const { return _top; } - size_t word_size() const { return _word_size; } size_t size() const volatile { return _word_size; } void set_size(size_t v) { _word_size = v; } - bool is_free() { return _is_free; } - void set_is_free(bool v) { _is_free = v; } - static size_t overhead() { return _overhead; } - void clear_next() { set_next(NULL); } - void link_prev(Metachunk* ptr) { set_prev(ptr); } - uintptr_t* end() { return ((uintptr_t*) this) + size(); } - bool cantCoalesce() const { return false; } - void link_next(Metachunk* ptr) { set_next(ptr); } - void link_after(Metachunk* ptr){ + + void link_next(T* ptr) { set_next(ptr); } + void link_prev(T* ptr) { set_prev(ptr); } + void link_after(T* ptr) { link_next(ptr); - if (ptr != NULL) ptr->link_prev(this); + if (ptr != NULL) ptr->link_prev((T*)this); } - // Reset top to bottom so chunk can be reused. - void reset_empty() { _top = (_bottom + _overhead); _next = NULL; _prev = NULL; } - bool is_empty() { return _top == (_bottom + _overhead); } + uintptr_t* end() const { return ((uintptr_t*) this) + size(); } - // used (has been allocated) - // free (available for future allocations) - // capacity (total size of chunk) - size_t used_word_size() const; - size_t free_word_size() const; - size_t capacity_word_size()const; + bool cantCoalesce() const { return false; } // Debug support #ifdef ASSERT @@ -114,14 +69,98 @@ void* next_addr() const { return (void*)&_next; } void* size_addr() const { return (void*)&_word_size; } #endif - bool verify_chunk_in_free_list(Metachunk* tc) const { return true; } + bool verify_chunk_in_free_list(T* tc) const { return true; } bool verify_par_locked() { return true; } void assert_is_mangled() const {/* Don't check "\*/} - NOT_PRODUCT(void mangle();) + bool is_free() { return true; } +}; + +// 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 --+ --+ + +class Metachunk : public Metabase { + friend class TestMetachunk; + // The VirtualSpaceNode containing this chunk. + VirtualSpaceNode* _container; + + // Current allocation top. + MetaWord* _top; + + DEBUG_ONLY(bool _is_tagged_free;) + + 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, including alignment. + static size_t overhead(); + + Metachunk(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; + +#ifdef ASSERT + void mangle(); + bool is_tagged_free() { return _is_tagged_free; } + void set_is_tagged_free(bool v) { _is_tagged_free = v; } +#endif void print_on(outputStream* st) const; void verify(); }; + +// Metablock is the unit of allocation from a Chunk. +// +// A Metablock may be reused by its SpaceManager but are never moved between +// SpaceManagers. There is no explicit link to the Metachunk +// from which it was allocated. Metablock may be deallocated and +// put on a freelist but the space is never freed, rather +// the Metachunk it is a part of will be deallocated when it's +// associated class loader is collected. + +class Metablock : public Metabase { + friend class VMStructs; + public: + Metablock(size_t word_size) : Metabase(word_size) {} +}; + #endif // SHARE_VM_MEMORY_METACHUNK_HPP diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/metaspace.cpp --- a/src/share/vm/memory/metaspace.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/metaspace.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -30,7 +30,6 @@ #include "memory/filemap.hpp" #include "memory/freeList.hpp" #include "memory/gcLocker.hpp" -#include "memory/metablock.hpp" #include "memory/metachunk.hpp" #include "memory/metaspace.hpp" #include "memory/metaspaceShared.hpp" @@ -49,8 +48,8 @@ typedef BinaryTreeDictionary BlockTreeDictionary; typedef BinaryTreeDictionary ChunkTreeDictionary; -// Define this macro to enable slow integrity checking of -// the free chunk lists + +// Set this constant to enable slow integrity checking of the free chunk lists const bool metaspace_slow_verify = false; // Parameters for stress mode testing @@ -92,24 +91,9 @@ uint MetaspaceGC::_shrink_factor = 0; bool MetaspaceGC::_should_concurrent_collect = false; -// Blocks of space for metadata are allocated out of Metachunks. -// -// Metachunk are allocated out of MetadataVirtualspaces and once -// allocated there is no explicit link between a Metachunk and -// the MetadataVirtualspaces from which it was allocated. -// -// Each SpaceManager maintains a -// list of the chunks it is using and the current chunk. The current -// chunk is the chunk from which allocations are done. Space freed in -// a chunk is placed on the free list of blocks (BlockFreelist) and -// reused from there. - typedef class FreeList ChunkList; // Manages the global free lists of chunks. -// Has three lists of free chunks, and a total size and -// count that includes all three - class ChunkManager : public CHeapObj { // Free list of chunks of different sizes. @@ -119,7 +103,6 @@ // HumongousChunk ChunkList _free_chunks[NumberOfFreeLists]; - // HumongousChunk ChunkTreeDictionary _humongous_dictionary; @@ -230,7 +213,6 @@ // to the allocation of a quantum of metadata). class BlockFreelist VALUE_OBJ_CLASS_SPEC { BlockTreeDictionary* _dictionary; - static Metablock* initialize_free_chunk(MetaWord* p, size_t word_size); // Only allocate and split from freelist if the size of the allocation // is at least 1/4th the size of the available block. @@ -258,6 +240,7 @@ void print_on(outputStream* st) const; }; +// A VirtualSpaceList node. class VirtualSpaceNode : public CHeapObj { friend class VirtualSpaceList; @@ -414,13 +397,13 @@ Metachunk* chunk = first_chunk(); Metachunk* invalid_chunk = (Metachunk*) top(); while (chunk < invalid_chunk ) { - assert(chunk->is_free(), "Should be marked free"); - MetaWord* next = ((MetaWord*)chunk) + chunk->word_size(); - chunk_manager->remove_chunk(chunk); - assert(chunk->next() == NULL && - chunk->prev() == NULL, - "Was not removed from its list"); - chunk = (Metachunk*) next; + assert(chunk->is_tagged_free(), "Should be tagged free"); + MetaWord* next = ((MetaWord*)chunk) + chunk->word_size(); + chunk_manager->remove_chunk(chunk); + assert(chunk->next() == NULL && + chunk->prev() == NULL, + "Was not removed from its list"); + chunk = (Metachunk*) next; } } @@ -434,7 +417,7 @@ // Don't count the chunks on the free lists. Those are // still part of the VirtualSpaceNode but not currently // counted. - if (!chunk->is_free()) { + if (!chunk->is_tagged_free()) { count++; } chunk = (Metachunk*) next; @@ -753,14 +736,11 @@ #endif size_t get_raw_word_size(size_t word_size) { - // If only the dictionary is going to be used (i.e., no - // indexed free list), then there is a minimum size requirement. - // MinChunkSize is a placeholder for the real minimum size JJJ size_t byte_size = word_size * BytesPerWord; - size_t raw_bytes_size = MAX2(byte_size, - Metablock::min_block_byte_size()); - raw_bytes_size = ARENA_ALIGN(raw_bytes_size); + size_t raw_bytes_size = MAX2(byte_size, sizeof(Metablock)); + raw_bytes_size = align_size_up(raw_bytes_size, Metachunk::object_alignment()); + size_t raw_word_size = raw_bytes_size / BytesPerWord; assert(raw_word_size * BytesPerWord == raw_bytes_size, "Size problem"); @@ -813,17 +793,8 @@ } } -Metablock* BlockFreelist::initialize_free_chunk(MetaWord* p, size_t word_size) { - Metablock* block = (Metablock*) p; - block->set_word_size(word_size); - block->set_prev(NULL); - block->set_next(NULL); - - return block; -} - void BlockFreelist::return_block(MetaWord* p, size_t word_size) { - Metablock* free_chunk = initialize_free_chunk(p, word_size); + Metablock* free_chunk = ::new (p) Metablock(word_size); if (dictionary() == NULL) { _dictionary = new BlockTreeDictionary(); } @@ -1069,7 +1040,7 @@ } // Chunk is being removed from the chunks free list. - dec_free_chunks_total(chunk->capacity_word_size()); + dec_free_chunks_total(chunk->word_size()); } // Walk the list of VirtualSpaceNodes and delete @@ -1760,7 +1731,7 @@ chunk->set_next(free_list->head()); free_list->set_head(chunk); // chunk is being returned to the chunk free list - inc_free_chunks_total(chunk->capacity_word_size()); + inc_free_chunks_total(chunk->word_size()); slow_locked_verify(); } @@ -1822,7 +1793,7 @@ } // Chunk is being removed from the chunks free list. - dec_free_chunks_total(chunk->capacity_word_size()); + dec_free_chunks_total(chunk->word_size()); // Remove it from the links to this freelist chunk->set_next(NULL); @@ -1830,7 +1801,7 @@ #ifdef ASSERT // Chunk is no longer on any freelist. Setting to false make container_count_slow() // work. - chunk->set_is_free(false); + chunk->set_is_tagged_free(false); #endif chunk->container()->inc_container_count(); @@ -1962,7 +1933,7 @@ for (ChunkIndex i = ZeroIndex; i < NumberOfInUseLists; i = next_chunk_index(i)) { Metachunk* chunk = chunks_in_use(i); while (chunk != NULL) { - sum += chunk->capacity_word_size(); + sum += chunk->word_size(); chunk = chunk->next(); } } @@ -2210,7 +2181,7 @@ // Capture the next link before it is changed // by the call to return_chunk_at_head(); Metachunk* next = cur->next(); - cur->set_is_free(true); + DEBUG_ONLY(cur->set_is_tagged_free(true);) list->return_chunk_at_head(cur); cur = next; } @@ -2282,7 +2253,7 @@ while (humongous_chunks != NULL) { #ifdef ASSERT - humongous_chunks->set_is_free(true); + humongous_chunks->set_is_tagged_free(true); #endif if (TraceMetadataChunkAllocation && Verbose) { gclog_or_tty->print(PTR_FORMAT " (" SIZE_FORMAT ") ", @@ -2545,7 +2516,7 @@ curr->print_on(out); curr_total += curr->word_size(); used += curr->used_word_size(); - capacity += curr->capacity_word_size(); + capacity += curr->word_size(); waste += curr->free_word_size() + curr->overhead();; } } @@ -3396,7 +3367,7 @@ } -Metablock* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size, +MetaWord* Metaspace::allocate(ClassLoaderData* loader_data, size_t word_size, bool read_only, MetaspaceObj::Type type, TRAPS) { if (HAS_PENDING_EXCEPTION) { assert(false, "Should not allocate with exception pending"); @@ -3415,10 +3386,14 @@ MetaWord* result = space->allocate(word_size, NonClassType); if (result == NULL) { report_out_of_shared_space(read_only ? SharedReadOnly : SharedReadWrite); - } else { - space->record_allocation(result, type, space->vsm()->get_raw_word_size(word_size)); } - return Metablock::initialize(result, word_size); + + space->record_allocation(result, type, space->vsm()->get_raw_word_size(word_size)); + + // Zero initialize. + Copy::fill_to_aligned_words((HeapWord*)result, word_size, 0); + + return result; } MetadataType mdtype = (type == MetaspaceObj::ClassType) ? ClassType : NonClassType; @@ -3443,7 +3418,10 @@ return NULL; } - return Metablock::initialize(result, word_size); + // Zero initialize. + Copy::fill_to_aligned_words((HeapWord*)result, word_size, 0); + + return result; } void Metaspace::report_metadata_oome(ClassLoaderData* loader_data, size_t word_size, MetadataType mdtype, TRAPS) { diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/memory/metaspace.hpp --- a/src/share/vm/memory/metaspace.hpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/memory/metaspace.hpp Tue Oct 15 14:28:51 2013 +0200 @@ -139,7 +139,6 @@ // Allocate space for metadata of type mdtype. This is space // within a Metachunk and is used by // allocate(ClassLoaderData*, size_t, bool, MetadataType, TRAPS) - // which returns a Metablock. MetaWord* allocate(size_t word_size, MetadataType mdtype); // Virtual Space lists for both classes and other metadata @@ -217,8 +216,8 @@ size_t used_bytes_slow(MetadataType mdtype) const; size_t capacity_bytes_slow(MetadataType mdtype) const; - static Metablock* allocate(ClassLoaderData* loader_data, size_t word_size, - bool read_only, MetaspaceObj::Type type, TRAPS); + static MetaWord* allocate(ClassLoaderData* loader_data, size_t word_size, + bool read_only, MetaspaceObj::Type type, TRAPS); void deallocate(MetaWord* ptr, size_t byte_size, bool is_class); MetaWord* expand_and_allocate(size_t size, diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/prims/jni.cpp --- a/src/share/vm/prims/jni.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/prims/jni.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -5059,6 +5059,7 @@ void TestReserveMemorySpecial_test(); void TestVirtualSpace_test(); void TestMetaspaceAux_test(); +void TestMetachunk_test(); #if INCLUDE_ALL_GCS void TestG1BiasedArray_test(); #endif @@ -5070,6 +5071,7 @@ run_unit_test(TestReserveMemorySpecial_test()); run_unit_test(TestVirtualSpace_test()); run_unit_test(TestMetaspaceAux_test()); + run_unit_test(TestMetachunk_test()); run_unit_test(GlobalDefinitions::test_globals()); run_unit_test(GCTimerAllTest::all()); run_unit_test(arrayOopDesc::test_max_array_length()); diff -r f16726924734 -r bdfbb1fb19ca src/share/vm/runtime/vmStructs.cpp --- a/src/share/vm/runtime/vmStructs.cpp Tue Oct 15 07:10:09 2013 -0700 +++ b/src/share/vm/runtime/vmStructs.cpp Tue Oct 15 14:28:51 2013 +0200 @@ -58,7 +58,7 @@ #include "memory/generation.hpp" #include "memory/generationSpec.hpp" #include "memory/heap.hpp" -#include "memory/metablock.hpp" +#include "memory/metachunk.hpp" #include "memory/referenceType.hpp" #include "memory/space.hpp" #include "memory/tenuredGeneration.hpp"