2017-11-21 09:47:55 -05:00
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/*
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* Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*
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*/
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#include "precompiled.hpp"
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2018-01-29 16:51:21 -05:00
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#include "gc/shared/oopStorage.inline.hpp"
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#include "gc/shared/oopStorageParState.inline.hpp"
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2017-11-21 09:47:55 -05:00
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#include "logging/log.hpp"
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#include "memory/allocation.inline.hpp"
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#include "runtime/atomic.hpp"
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#include "runtime/handles.inline.hpp"
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#include "runtime/mutex.hpp"
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#include "runtime/mutexLocker.hpp"
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#include "runtime/orderAccess.inline.hpp"
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#include "runtime/safepoint.hpp"
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#include "runtime/stubRoutines.hpp"
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#include "utilities/align.hpp"
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#include "utilities/count_trailing_zeros.hpp"
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#include "utilities/debug.hpp"
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#include "utilities/globalDefinitions.hpp"
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#include "utilities/macros.hpp"
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#include "utilities/ostream.hpp"
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OopStorage::BlockEntry::BlockEntry() : _prev(NULL), _next(NULL) {}
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OopStorage::BlockEntry::~BlockEntry() {
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assert(_prev == NULL, "deleting attached block");
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assert(_next == NULL, "deleting attached block");
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}
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OopStorage::BlockList::BlockList(const BlockEntry& (*get_entry)(const Block& block)) :
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_head(NULL), _tail(NULL), _get_entry(get_entry)
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{}
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OopStorage::BlockList::~BlockList() {
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// ~OopStorage() empties its lists before destroying them.
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assert(_head == NULL, "deleting non-empty block list");
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assert(_tail == NULL, "deleting non-empty block list");
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}
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void OopStorage::BlockList::push_front(const Block& block) {
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const Block* old = _head;
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if (old == NULL) {
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assert(_tail == NULL, "invariant");
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_head = _tail = █
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} else {
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_get_entry(block)._next = old;
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_get_entry(*old)._prev = █
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_head = █
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}
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}
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void OopStorage::BlockList::push_back(const Block& block) {
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const Block* old = _tail;
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if (old == NULL) {
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assert(_head == NULL, "invariant");
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_head = _tail = █
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} else {
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_get_entry(*old)._next = █
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_get_entry(block)._prev = old;
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_tail = █
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}
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}
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void OopStorage::BlockList::unlink(const Block& block) {
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const BlockEntry& block_entry = _get_entry(block);
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const Block* prev_blk = block_entry._prev;
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const Block* next_blk = block_entry._next;
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block_entry._prev = NULL;
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block_entry._next = NULL;
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if ((prev_blk == NULL) && (next_blk == NULL)) {
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assert(_head == &block, "invariant");
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assert(_tail == &block, "invariant");
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_head = _tail = NULL;
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} else if (prev_blk == NULL) {
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assert(_head == &block, "invariant");
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_get_entry(*next_blk)._prev = NULL;
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_head = next_blk;
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} else if (next_blk == NULL) {
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assert(_tail == &block, "invariant");
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_get_entry(*prev_blk)._next = NULL;
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_tail = prev_blk;
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} else {
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_get_entry(*next_blk)._prev = prev_blk;
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_get_entry(*prev_blk)._next = next_blk;
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}
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}
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// Blocks start with an array of BitsPerWord oop entries. That array
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// is divided into conceptual BytesPerWord sections of BitsPerWord
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// entries. Blocks are allocated aligned on section boundaries, for
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// the convenience of mapping from an entry to the containing block;
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// see block_for_ptr(). Aligning on section boundary rather than on
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// the full _data wastes a lot less space, but makes for a bit more
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// work in block_for_ptr().
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const unsigned section_size = BitsPerByte;
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const unsigned section_count = BytesPerWord;
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const unsigned block_alignment = sizeof(oop) * section_size;
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// VS2013 warns (C4351) that elements of _data will be *correctly* default
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// initialized, unlike earlier versions that *incorrectly* did not do so.
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#ifdef _WINDOWS
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#pragma warning(push)
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#pragma warning(disable: 4351)
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#endif // _WINDOWS
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OopStorage::Block::Block(const OopStorage* owner, void* memory) :
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_data(),
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_allocated_bitmask(0),
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_owner(owner),
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_memory(memory),
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_active_entry(),
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_allocate_entry()
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{
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STATIC_ASSERT(_data_pos == 0);
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STATIC_ASSERT(section_size * section_count == ARRAY_SIZE(_data));
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assert(offset_of(Block, _data) == _data_pos, "invariant");
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assert(owner != NULL, "NULL owner");
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assert(is_aligned(this, block_alignment), "misaligned block");
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}
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#ifdef _WINDOWS
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#pragma warning(pop)
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#endif
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OopStorage::Block::~Block() {
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// Clear fields used by block_for_ptr and entry validation, which
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// might help catch bugs. Volatile to prevent dead-store elimination.
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const_cast<uintx volatile&>(_allocated_bitmask) = 0;
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const_cast<OopStorage* volatile&>(_owner) = NULL;
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}
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const OopStorage::BlockEntry& OopStorage::Block::get_active_entry(const Block& block) {
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return block._active_entry;
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}
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const OopStorage::BlockEntry& OopStorage::Block::get_allocate_entry(const Block& block) {
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return block._allocate_entry;
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}
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size_t OopStorage::Block::allocation_size() {
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// _data must be first member, so aligning Block aligns _data.
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STATIC_ASSERT(_data_pos == 0);
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return sizeof(Block) + block_alignment - sizeof(void*);
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}
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size_t OopStorage::Block::allocation_alignment_shift() {
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return exact_log2(block_alignment);
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}
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inline bool is_full_bitmask(uintx bitmask) { return ~bitmask == 0; }
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inline bool is_empty_bitmask(uintx bitmask) { return bitmask == 0; }
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bool OopStorage::Block::is_full() const {
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return is_full_bitmask(allocated_bitmask());
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}
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bool OopStorage::Block::is_empty() const {
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return is_empty_bitmask(allocated_bitmask());
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}
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uintx OopStorage::Block::bitmask_for_entry(const oop* ptr) const {
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return bitmask_for_index(get_index(ptr));
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}
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uintx OopStorage::Block::cmpxchg_allocated_bitmask(uintx new_value, uintx compare_value) {
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return Atomic::cmpxchg(new_value, &_allocated_bitmask, compare_value);
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}
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bool OopStorage::Block::contains(const oop* ptr) const {
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const oop* base = get_pointer(0);
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return (base <= ptr) && (ptr < (base + ARRAY_SIZE(_data)));
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}
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unsigned OopStorage::Block::get_index(const oop* ptr) const {
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assert(contains(ptr), PTR_FORMAT " not in block " PTR_FORMAT, p2i(ptr), p2i(this));
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return static_cast<unsigned>(ptr - get_pointer(0));
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}
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oop* OopStorage::Block::allocate() {
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// Use CAS loop because release may change bitmask outside of lock.
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uintx allocated = allocated_bitmask();
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while (true) {
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assert(!is_full_bitmask(allocated), "attempt to allocate from full block");
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unsigned index = count_trailing_zeros(~allocated);
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uintx new_value = allocated | bitmask_for_index(index);
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uintx fetched = cmpxchg_allocated_bitmask(new_value, allocated);
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if (fetched == allocated) {
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return get_pointer(index); // CAS succeeded; return entry for index.
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}
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allocated = fetched; // CAS failed; retry with latest value.
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}
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}
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OopStorage::Block* OopStorage::Block::new_block(const OopStorage* owner) {
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// _data must be first member: aligning block => aligning _data.
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STATIC_ASSERT(_data_pos == 0);
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size_t size_needed = allocation_size();
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void* memory = NEW_C_HEAP_ARRAY_RETURN_NULL(char, size_needed, mtGC);
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if (memory == NULL) {
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return NULL;
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}
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void* block_mem = align_up(memory, block_alignment);
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assert(sizeof(Block) + pointer_delta(block_mem, memory, 1) <= size_needed,
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"allocated insufficient space for aligned block");
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return ::new (block_mem) Block(owner, memory);
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}
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void OopStorage::Block::delete_block(const Block& block) {
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void* memory = block._memory;
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block.Block::~Block();
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FREE_C_HEAP_ARRAY(char, memory);
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}
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// This can return a false positive if ptr is not contained by some
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// block. For some uses, it is a precondition that ptr is valid,
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// e.g. contained in some block in owner's _active_list. Other uses
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// require additional validation of the result.
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OopStorage::Block*
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OopStorage::Block::block_for_ptr(const OopStorage* owner, const oop* ptr) {
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assert(CanUseSafeFetchN(), "precondition");
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STATIC_ASSERT(_data_pos == 0);
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// Const-ness of ptr is not related to const-ness of containing block.
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// Blocks are allocated section-aligned, so get the containing section.
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oop* section_start = align_down(const_cast<oop*>(ptr), block_alignment);
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// Start with a guess that the containing section is the last section,
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// so the block starts section_count-1 sections earlier.
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oop* section = section_start - (section_size * (section_count - 1));
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// Walk up through the potential block start positions, looking for
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// the owner in the expected location. If we're below the actual block
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// start position, the value at the owner position will be some oop
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// (possibly NULL), which can never match the owner.
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intptr_t owner_addr = reinterpret_cast<intptr_t>(owner);
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for (unsigned i = 0; i < section_count; ++i, section += section_size) {
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Block* candidate = reinterpret_cast<Block*>(section);
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intptr_t* candidate_owner_addr
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= reinterpret_cast<intptr_t*>(&candidate->_owner);
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if (SafeFetchN(candidate_owner_addr, 0) == owner_addr) {
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return candidate;
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}
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}
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return NULL;
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}
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bool OopStorage::is_valid_block_locked_or_safepoint(const Block* check_block) const {
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assert_locked_or_safepoint(_allocate_mutex);
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// For now, simple linear search. Do something more clever if this
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// is a performance bottleneck, particularly for allocation_status.
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for (const Block* block = _active_list.chead();
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block != NULL;
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block = _active_list.next(*block)) {
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if (check_block == block) {
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return true;
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}
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}
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return false;
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}
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#ifdef ASSERT
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void OopStorage::assert_at_safepoint() {
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assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
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}
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#endif // ASSERT
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//////////////////////////////////////////////////////////////////////////////
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// Allocation
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//
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// Allocation involves the _allocate_list, which contains a subset of the
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// blocks owned by a storage object. This is a doubly-linked list, linked
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// through dedicated fields in the blocks. Full blocks are removed from this
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// list, though they are still present in the _active_list. Empty blocks are
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// kept at the end of the _allocate_list, to make it easy for empty block
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// deletion to find them.
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//
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// allocate(), release(), and delete_empty_blocks_concurrent() all lock the
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// _allocate_mutex while performing any list modifications.
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//
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// allocate() and release() update a block's _allocated_bitmask using CAS
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// loops. This prevents loss of updates even though release() may perform
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// some updates without any locking.
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//
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// allocate() obtains the entry from the first block in the _allocate_list,
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// and updates that block's _allocated_bitmask to indicate the entry is in
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// use. If this makes the block full (all entries in use), the block is
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// removed from the _allocate_list so it won't be considered by future
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// allocations until some entries in it are relased.
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//
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// release() looks up the block for the entry without locking. Once the block
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// has been determined, its _allocated_bitmask needs to be updated, and its
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// position in the _allocate_list may need to be updated. There are two
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// cases:
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//
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// (a) If the block is neither full nor would become empty with the release of
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// the entry, only its _allocated_bitmask needs to be updated. But if the CAS
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// update fails, the applicable case may change for the retry.
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//
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// (b) Otherwise, the _allocate_list will also need to be modified. This
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// requires locking the _allocate_mutex, and then attempting to CAS the
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// _allocated_bitmask. If the CAS fails, the applicable case may change for
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// the retry. If the CAS succeeds, then update the _allocate_list according
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// to the the state changes. If the block changed from full to not full, then
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// it needs to be added to the _allocate_list, for use in future allocations.
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// If the block changed from not empty to empty, then it is moved to the end
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// of the _allocate_list, for ease of empty block deletion processing.
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oop* OopStorage::allocate() {
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MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
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Block* block = _allocate_list.head();
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if (block == NULL) {
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// No available blocks; make a new one, and add to storage.
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{
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MutexUnlockerEx mul(_allocate_mutex, Mutex::_no_safepoint_check_flag);
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block = Block::new_block(this);
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}
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if (block != NULL) {
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// Add new block to storage.
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log_info(oopstorage, blocks)("%s: new block " PTR_FORMAT, name(), p2i(block));
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// Add to end of _allocate_list. The mutex release allowed
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|
|
// other threads to add blocks to the _allocate_list. We prefer
|
|
|
|
// to allocate from non-empty blocks, to allow empty blocks to
|
|
|
|
// be deleted.
|
|
|
|
_allocate_list.push_back(*block);
|
|
|
|
++_empty_block_count;
|
|
|
|
// Add to front of _active_list, and then record as the head
|
|
|
|
// block, for concurrent iteration protocol.
|
|
|
|
_active_list.push_front(*block);
|
|
|
|
++_block_count;
|
|
|
|
// Ensure all setup of block is complete before making it visible.
|
|
|
|
OrderAccess::release_store(&_active_head, block);
|
|
|
|
} else {
|
|
|
|
log_info(oopstorage, blocks)("%s: failed new block allocation", name());
|
|
|
|
}
|
|
|
|
block = _allocate_list.head();
|
|
|
|
if (block == NULL) {
|
|
|
|
// Failed to make new block, and no other thread made a block
|
|
|
|
// available while the mutex was released, so return failure.
|
|
|
|
return NULL;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// Allocate from first block.
|
|
|
|
assert(block != NULL, "invariant");
|
|
|
|
assert(!block->is_full(), "invariant");
|
|
|
|
if (block->is_empty()) {
|
|
|
|
// Transitioning from empty to not empty.
|
|
|
|
log_debug(oopstorage, blocks)("%s: block not empty " PTR_FORMAT, name(), p2i(block));
|
|
|
|
--_empty_block_count;
|
|
|
|
}
|
|
|
|
oop* result = block->allocate();
|
|
|
|
assert(result != NULL, "allocation failed");
|
|
|
|
assert(!block->is_empty(), "postcondition");
|
|
|
|
Atomic::inc(&_allocation_count); // release updates outside lock.
|
|
|
|
if (block->is_full()) {
|
|
|
|
// Transitioning from not full to full.
|
|
|
|
// Remove full blocks from consideration by future allocates.
|
|
|
|
log_debug(oopstorage, blocks)("%s: block full " PTR_FORMAT, name(), p2i(block));
|
|
|
|
_allocate_list.unlink(*block);
|
|
|
|
}
|
|
|
|
log_info(oopstorage, ref)("%s: allocated " PTR_FORMAT, name(), p2i(result));
|
|
|
|
return result;
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::Block* OopStorage::find_block_or_null(const oop* ptr) const {
|
|
|
|
assert(ptr != NULL, "precondition");
|
|
|
|
return Block::block_for_ptr(this, ptr);
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::release_from_block(Block& block, uintx releasing) {
|
|
|
|
assert(releasing != 0, "invariant");
|
|
|
|
uintx allocated = block.allocated_bitmask();
|
|
|
|
while (true) {
|
|
|
|
assert(releasing == (allocated & releasing), "invariant");
|
|
|
|
uintx new_value = allocated ^ releasing;
|
|
|
|
// CAS new_value into block's allocated bitmask, retrying with
|
|
|
|
// updated allocated bitmask until the CAS succeeds.
|
|
|
|
uintx fetched;
|
|
|
|
if (!is_full_bitmask(allocated) && !is_empty_bitmask(new_value)) {
|
|
|
|
fetched = block.cmpxchg_allocated_bitmask(new_value, allocated);
|
|
|
|
if (fetched == allocated) return;
|
|
|
|
} else {
|
|
|
|
// Need special handling if transitioning from full to not full,
|
|
|
|
// or from not empty to empty. For those cases, must hold the
|
|
|
|
// _allocation_mutex when updating the allocated bitmask, to
|
|
|
|
// ensure the associated list manipulations will be consistent
|
|
|
|
// with the allocation bitmask that is visible to other threads
|
|
|
|
// in allocate() or deleting empty blocks.
|
|
|
|
MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
|
|
|
|
fetched = block.cmpxchg_allocated_bitmask(new_value, allocated);
|
|
|
|
if (fetched == allocated) {
|
|
|
|
// CAS succeeded; handle special cases, which might no longer apply.
|
|
|
|
if (is_full_bitmask(allocated)) {
|
|
|
|
// Transitioning from full to not-full; add to _allocate_list.
|
|
|
|
log_debug(oopstorage, blocks)("%s: block not full " PTR_FORMAT, name(), p2i(&block));
|
|
|
|
_allocate_list.push_front(block);
|
|
|
|
assert(!block.is_full(), "invariant"); // Still not full.
|
|
|
|
}
|
|
|
|
if (is_empty_bitmask(new_value)) {
|
|
|
|
// Transitioning from not-empty to empty; move to end of
|
|
|
|
// _allocate_list, to make it a deletion candidate.
|
|
|
|
log_debug(oopstorage, blocks)("%s: block empty " PTR_FORMAT, name(), p2i(&block));
|
|
|
|
_allocate_list.unlink(block);
|
|
|
|
_allocate_list.push_back(block);
|
|
|
|
++_empty_block_count;
|
|
|
|
assert(block.is_empty(), "invariant"); // Still empty.
|
|
|
|
}
|
|
|
|
return; // Successful CAS and transitions handled.
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// CAS failed; retry with latest value.
|
|
|
|
allocated = fetched;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
#ifdef ASSERT
|
|
|
|
void OopStorage::check_release(const Block* block, const oop* ptr) const {
|
|
|
|
switch (allocation_status_validating_block(block, ptr)) {
|
|
|
|
case INVALID_ENTRY:
|
|
|
|
fatal("Releasing invalid entry: " PTR_FORMAT, p2i(ptr));
|
|
|
|
break;
|
|
|
|
|
|
|
|
case UNALLOCATED_ENTRY:
|
|
|
|
fatal("Releasing unallocated entry: " PTR_FORMAT, p2i(ptr));
|
|
|
|
break;
|
|
|
|
|
|
|
|
case ALLOCATED_ENTRY:
|
|
|
|
assert(block->contains(ptr), "invariant");
|
|
|
|
break;
|
|
|
|
|
|
|
|
default:
|
|
|
|
ShouldNotReachHere();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
#endif // ASSERT
|
|
|
|
|
|
|
|
inline void check_release_entry(const oop* entry) {
|
|
|
|
assert(entry != NULL, "Releasing NULL");
|
|
|
|
assert(*entry == NULL, "Releasing uncleared entry: " PTR_FORMAT, p2i(entry));
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::release(const oop* ptr) {
|
|
|
|
check_release_entry(ptr);
|
|
|
|
Block* block = find_block_or_null(ptr);
|
|
|
|
check_release(block, ptr);
|
|
|
|
log_info(oopstorage, ref)("%s: released " PTR_FORMAT, name(), p2i(ptr));
|
|
|
|
release_from_block(*block, block->bitmask_for_entry(ptr));
|
|
|
|
Atomic::dec(&_allocation_count);
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::release(const oop* const* ptrs, size_t size) {
|
|
|
|
size_t i = 0;
|
|
|
|
while (i < size) {
|
2018-01-23 14:27:10 -05:00
|
|
|
check_release_entry(ptrs[i]);
|
2017-11-21 09:47:55 -05:00
|
|
|
Block* block = find_block_or_null(ptrs[i]);
|
|
|
|
check_release(block, ptrs[i]);
|
|
|
|
log_info(oopstorage, ref)("%s: released " PTR_FORMAT, name(), p2i(ptrs[i]));
|
|
|
|
size_t count = 0;
|
|
|
|
uintx releasing = 0;
|
|
|
|
for ( ; i < size; ++i) {
|
|
|
|
const oop* entry = ptrs[i];
|
|
|
|
// If entry not in block, finish block and resume outer loop with entry.
|
|
|
|
if (!block->contains(entry)) break;
|
|
|
|
check_release_entry(entry);
|
|
|
|
// Add entry to releasing bitmap.
|
|
|
|
log_info(oopstorage, ref)("%s: released " PTR_FORMAT, name(), p2i(entry));
|
|
|
|
uintx entry_bitmask = block->bitmask_for_entry(entry);
|
|
|
|
assert((releasing & entry_bitmask) == 0,
|
|
|
|
"Duplicate entry: " PTR_FORMAT, p2i(entry));
|
|
|
|
releasing |= entry_bitmask;
|
|
|
|
++count;
|
|
|
|
}
|
|
|
|
// Release the contiguous entries that are in block.
|
|
|
|
release_from_block(*block, releasing);
|
|
|
|
Atomic::sub(count, &_allocation_count);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
const char* dup_name(const char* name) {
|
|
|
|
char* dup = NEW_C_HEAP_ARRAY(char, strlen(name) + 1, mtGC);
|
|
|
|
strcpy(dup, name);
|
|
|
|
return dup;
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::OopStorage(const char* name,
|
|
|
|
Mutex* allocate_mutex,
|
|
|
|
Mutex* active_mutex) :
|
|
|
|
_name(dup_name(name)),
|
|
|
|
_active_list(&Block::get_active_entry),
|
|
|
|
_allocate_list(&Block::get_allocate_entry),
|
|
|
|
_active_head(NULL),
|
|
|
|
_allocate_mutex(allocate_mutex),
|
|
|
|
_active_mutex(active_mutex),
|
|
|
|
_allocation_count(0),
|
|
|
|
_block_count(0),
|
|
|
|
_empty_block_count(0),
|
|
|
|
_concurrent_iteration_active(false)
|
|
|
|
{
|
|
|
|
assert(_active_mutex->rank() < _allocate_mutex->rank(),
|
|
|
|
"%s: active_mutex must have lower rank than allocate_mutex", _name);
|
|
|
|
assert(_active_mutex->_safepoint_check_required != Mutex::_safepoint_check_always,
|
|
|
|
"%s: active mutex requires safepoint check", _name);
|
|
|
|
assert(_allocate_mutex->_safepoint_check_required != Mutex::_safepoint_check_always,
|
|
|
|
"%s: allocate mutex requires safepoint check", _name);
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::delete_empty_block(const Block& block) {
|
|
|
|
assert(block.is_empty(), "discarding non-empty block");
|
|
|
|
log_info(oopstorage, blocks)("%s: delete empty block " PTR_FORMAT, name(), p2i(&block));
|
|
|
|
Block::delete_block(block);
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::~OopStorage() {
|
|
|
|
Block* block;
|
|
|
|
while ((block = _allocate_list.head()) != NULL) {
|
|
|
|
_allocate_list.unlink(*block);
|
|
|
|
}
|
|
|
|
while ((block = _active_list.head()) != NULL) {
|
|
|
|
_active_list.unlink(*block);
|
|
|
|
Block::delete_block(*block);
|
|
|
|
}
|
|
|
|
FREE_C_HEAP_ARRAY(char, _name);
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::delete_empty_blocks_safepoint(size_t retain) {
|
|
|
|
assert_at_safepoint();
|
|
|
|
// Don't interfere with a concurrent iteration.
|
|
|
|
if (_concurrent_iteration_active) return;
|
|
|
|
// Compute the number of blocks to remove, to minimize volatile accesses.
|
|
|
|
size_t empty_blocks = _empty_block_count;
|
|
|
|
if (retain < empty_blocks) {
|
|
|
|
size_t remove_count = empty_blocks - retain;
|
|
|
|
// Update volatile counters once.
|
|
|
|
_block_count -= remove_count;
|
|
|
|
_empty_block_count -= remove_count;
|
|
|
|
do {
|
|
|
|
const Block* block = _allocate_list.ctail();
|
|
|
|
assert(block != NULL, "invariant");
|
|
|
|
assert(block->is_empty(), "invariant");
|
|
|
|
// Remove block from lists, and delete it.
|
|
|
|
_active_list.unlink(*block);
|
|
|
|
_allocate_list.unlink(*block);
|
|
|
|
delete_empty_block(*block);
|
|
|
|
} while (--remove_count > 0);
|
|
|
|
// Update _active_head, in case current value was in deleted set.
|
|
|
|
_active_head = _active_list.head();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::delete_empty_blocks_concurrent(size_t retain) {
|
|
|
|
MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
|
|
|
|
// Other threads could be adding to the empty block count while we
|
|
|
|
// release the mutex across the block deletions. Set an upper bound
|
|
|
|
// on how many blocks we'll try to release, so other threads can't
|
|
|
|
// cause an unbounded stay in this function.
|
|
|
|
if (_empty_block_count <= retain) return;
|
|
|
|
size_t limit = _empty_block_count - retain;
|
|
|
|
for (size_t i = 0; (i < limit) && (retain < _empty_block_count); ++i) {
|
|
|
|
const Block* block = _allocate_list.ctail();
|
|
|
|
assert(block != NULL, "invariant");
|
|
|
|
assert(block->is_empty(), "invariant");
|
|
|
|
{
|
|
|
|
MutexLockerEx aml(_active_mutex, Mutex::_no_safepoint_check_flag);
|
|
|
|
// Don't interfere with a concurrent iteration.
|
|
|
|
if (_concurrent_iteration_active) return;
|
|
|
|
// Remove block from _active_list, updating head if needed.
|
|
|
|
_active_list.unlink(*block);
|
|
|
|
--_block_count;
|
|
|
|
if (block == _active_head) {
|
|
|
|
_active_head = _active_list.head();
|
|
|
|
}
|
|
|
|
}
|
|
|
|
// Remove block from _allocate_list and delete it.
|
|
|
|
_allocate_list.unlink(*block);
|
|
|
|
--_empty_block_count;
|
|
|
|
// Release mutex while deleting block.
|
|
|
|
MutexUnlockerEx ul(_allocate_mutex, Mutex::_no_safepoint_check_flag);
|
|
|
|
delete_empty_block(*block);
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::EntryStatus
|
|
|
|
OopStorage::allocation_status_validating_block(const Block* block,
|
|
|
|
const oop* ptr) const {
|
|
|
|
MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
|
|
|
|
if ((block == NULL) || !is_valid_block_locked_or_safepoint(block)) {
|
|
|
|
return INVALID_ENTRY;
|
|
|
|
} else if ((block->allocated_bitmask() & block->bitmask_for_entry(ptr)) != 0) {
|
|
|
|
return ALLOCATED_ENTRY;
|
|
|
|
} else {
|
|
|
|
return UNALLOCATED_ENTRY;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::EntryStatus OopStorage::allocation_status(const oop* ptr) const {
|
|
|
|
return allocation_status_validating_block(find_block_or_null(ptr), ptr);
|
|
|
|
}
|
|
|
|
|
|
|
|
size_t OopStorage::allocation_count() const {
|
|
|
|
return _allocation_count;
|
|
|
|
}
|
|
|
|
|
|
|
|
size_t OopStorage::block_count() const {
|
|
|
|
return _block_count;
|
|
|
|
}
|
|
|
|
|
|
|
|
size_t OopStorage::empty_block_count() const {
|
|
|
|
return _empty_block_count;
|
|
|
|
}
|
|
|
|
|
|
|
|
size_t OopStorage::total_memory_usage() const {
|
|
|
|
size_t total_size = sizeof(OopStorage);
|
|
|
|
total_size += strlen(name()) + 1;
|
|
|
|
total_size += block_count() * Block::allocation_size();
|
|
|
|
return total_size;
|
|
|
|
}
|
|
|
|
|
|
|
|
// Parallel iteration support
|
|
|
|
#if INCLUDE_ALL_GCS
|
|
|
|
|
|
|
|
static char* not_started_marker_dummy = NULL;
|
|
|
|
static void* const not_started_marker = ¬_started_marker_dummy;
|
|
|
|
|
|
|
|
OopStorage::BasicParState::BasicParState(OopStorage* storage, bool concurrent) :
|
|
|
|
_storage(storage),
|
|
|
|
_next_block(not_started_marker),
|
|
|
|
_concurrent(concurrent)
|
|
|
|
{
|
|
|
|
update_iteration_state(true);
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::BasicParState::~BasicParState() {
|
|
|
|
update_iteration_state(false);
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::BasicParState::update_iteration_state(bool value) {
|
|
|
|
if (_concurrent) {
|
|
|
|
MutexLockerEx ml(_storage->_active_mutex, Mutex::_no_safepoint_check_flag);
|
|
|
|
assert(_storage->_concurrent_iteration_active != value, "precondition");
|
|
|
|
_storage->_concurrent_iteration_active = value;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
void OopStorage::BasicParState::ensure_iteration_started() {
|
|
|
|
if (!_concurrent) assert_at_safepoint();
|
|
|
|
assert(!_concurrent || _storage->_concurrent_iteration_active, "invariant");
|
|
|
|
// Ensure _next_block is not the not_started_marker, setting it to
|
|
|
|
// the _active_head to start the iteration if necessary.
|
|
|
|
if (OrderAccess::load_acquire(&_next_block) == not_started_marker) {
|
|
|
|
Atomic::cmpxchg(_storage->_active_head, &_next_block, not_started_marker);
|
|
|
|
}
|
|
|
|
assert(_next_block != not_started_marker, "postcondition");
|
|
|
|
}
|
|
|
|
|
|
|
|
OopStorage::Block* OopStorage::BasicParState::claim_next_block() {
|
|
|
|
assert(_next_block != not_started_marker, "Iteration not started");
|
|
|
|
void* next = _next_block;
|
|
|
|
while (next != NULL) {
|
|
|
|
void* new_next = _storage->_active_list.next(*static_cast<Block*>(next));
|
|
|
|
void* fetched = Atomic::cmpxchg(new_next, &_next_block, next);
|
|
|
|
if (fetched == next) break; // Claimed.
|
|
|
|
next = fetched;
|
|
|
|
}
|
|
|
|
return static_cast<Block*>(next);
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}
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#endif // INCLUDE_ALL_GCS
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const char* OopStorage::name() const { return _name; }
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#ifndef PRODUCT
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void OopStorage::print_on(outputStream* st) const {
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size_t allocations = _allocation_count;
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size_t blocks = _block_count;
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size_t empties = _empty_block_count;
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// Comparison is being careful about racy accesses.
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size_t used = (blocks < empties) ? 0 : (blocks - empties);
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double data_size = section_size * section_count;
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double alloc_percentage = percent_of((double)allocations, used * data_size);
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st->print("%s: " SIZE_FORMAT " entries in " SIZE_FORMAT " blocks (%.F%%), "
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SIZE_FORMAT " empties, " SIZE_FORMAT " bytes",
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name(), allocations, used, alloc_percentage,
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empties, total_memory_usage());
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if (_concurrent_iteration_active) {
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st->print(", concurrent iteration active");
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}
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}
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#endif // !PRODUCT
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