jdk-sandbox: comparison src/hotspot/share/gc/shared/oopStorage.cpp

equal deleted inserted replaced

-:00e159258897
+:e1d09bd56d2d
 #include "precompiled.hpp"
 #include "gc/shared/oopStorage.inline.hpp"
 #include "gc/shared/oopStorageParState.inline.hpp"
 #include "logging/log.hpp"
+#include "logging/logStream.hpp"
 #include "memory/allocation.inline.hpp"
+#include "memory/resourceArea.hpp"
 #include "runtime/atomic.hpp"
 #include "runtime/handles.inline.hpp"
 #include "runtime/mutex.hpp"
 #include "runtime/mutexLocker.hpp"
 #include "runtime/orderAccess.inline.hpp"
 _get_entry(*prev_blk)._next = next_blk;
 }
 }
 // Blocks start with an array of BitsPerWord oop entries.  That array
-// is divided into conceptual BytesPerWord sections of BitsPerWord
+// is divided into conceptual BytesPerWord sections of BitsPerByte
 // entries.  Blocks are allocated aligned on section boundaries, for
 // the convenience of mapping from an entry to the containing block;
 // see block_for_ptr().  Aligning on section boundary rather than on
 // the full _data wastes a lot less space, but makes for a bit more
 // work in block_for_ptr().
 _data(),
 _allocated_bitmask(0),
 _owner(owner),
 _memory(memory),
 _active_entry(),
-_allocate_entry()
+_allocate_entry(),
+_deferred_updates_next(NULL),
+_release_refcount(0)
 {
 STATIC_ASSERT(_data_pos == 0);
 STATIC_ASSERT(section_size * section_count == ARRAY_SIZE(_data));
 assert(offset_of(Block, _data) == _data_pos, "invariant");
 assert(owner != NULL, "NULL owner");
 #ifdef _WINDOWS
 #pragma warning(pop)
 #endif
 OopStorage::Block::~Block() {
+assert(_release_refcount == 0, "deleting block while releasing");
+assert(_deferred_updates_next == NULL, "deleting block with deferred update");
 // Clear fields used by block_for_ptr and entry validation, which
 // might help catch bugs.  Volatile to prevent dead-store elimination.
 const_cast<uintx volatile&>(_allocated_bitmask) = 0;
 const_cast<OopStorage* volatile&>(_owner) = NULL;
 }
 uintx OopStorage::Block::bitmask_for_entry(const oop* ptr) const {
 return bitmask_for_index(get_index(ptr));
 }
-uintx OopStorage::Block::cmpxchg_allocated_bitmask(uintx new_value, uintx compare_value) {
+// A block is deletable if
-return Atomic::cmpxchg(new_value, &_allocated_bitmask, compare_value);
+// (1) It is empty.
+// (2) There is not a release() operation currently operating on it.
+// (3) It is not in the deferred updates list.
+// The order of tests is important for proper interaction between release()
+// and concurrent deletion.
+bool OopStorage::Block::is_deletable() const {
+return (OrderAccess::load_acquire(&_allocated_bitmask) == 0) &&
+(OrderAccess::load_acquire(&_release_refcount) == 0) &&
+(OrderAccess::load_acquire(&_deferred_updates_next) == NULL);
+}
+OopStorage::Block* OopStorage::Block::deferred_updates_next() const {
+return _deferred_updates_next;
+}
+void OopStorage::Block::set_deferred_updates_next(Block* block) {
+_deferred_updates_next = block;
 }
 bool OopStorage::Block::contains(const oop* ptr) const {
 const oop* base = get_pointer(0);
 return (base <= ptr) && (ptr < (base + ARRAY_SIZE(_data)));
 uintx allocated = allocated_bitmask();
 while (true) {
 assert(!is_full_bitmask(allocated), "attempt to allocate from full block");
 unsigned index = count_trailing_zeros(~allocated);
 uintx new_value = allocated | bitmask_for_index(index);
-uintx fetched = cmpxchg_allocated_bitmask(new_value, allocated);
+uintx fetched = Atomic::cmpxchg(new_value, &_allocated_bitmask, allocated);
 if (fetched == allocated) {
 return get_pointer(index); // CAS succeeded; return entry for index.
 }
 allocated = fetched;       // CAS failed; retry with latest value.
 }
 }
 }
 return NULL;
 }
-bool OopStorage::is_valid_block_locked_or_safepoint(const Block* check_block) const {
-assert_locked_or_safepoint(_allocate_mutex);
-// For now, simple linear search.  Do something more clever if this
-// is a performance bottleneck, particularly for allocation_status.
-for (const Block* block = _active_list.chead();
-block != NULL;
-block = _active_list.next(*block)) {
-if (check_block == block) {
-return true;
-}
-}
-return false;
-}
 #ifdef ASSERT
 void OopStorage::assert_at_safepoint() {
 assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint");
 }
 #endif // ASSERT
 // through dedicated fields in the blocks.  Full blocks are removed from this
 // list, though they are still present in the _active_list.  Empty blocks are
 // kept at the end of the _allocate_list, to make it easy for empty block
 // deletion to find them.
 //
-// allocate(), release(), and delete_empty_blocks_concurrent() all lock the
+// allocate(), and delete_empty_blocks_concurrent() lock the
 // _allocate_mutex while performing any list modifications.
 //
 // allocate() and release() update a block's _allocated_bitmask using CAS
-// loops.  This prevents loss of updates even though release() may perform
+// loops.  This prevents loss of updates even though release() performs
-// some updates without any locking.
+// its updates without any locking.
 //
 // allocate() obtains the entry from the first block in the _allocate_list,
 // and updates that block's _allocated_bitmask to indicate the entry is in
 // use.  If this makes the block full (all entries in use), the block is
 // removed from the _allocate_list so it won't be considered by future
-// allocations until some entries in it are relased.
+// allocations until some entries in it are released.
 //
-// release() looks up the block for the entry without locking.  Once the block
+// release() is performed lock-free. release() first looks up the block for
-// has been determined, its _allocated_bitmask needs to be updated, and its
+// the entry, using address alignment to find the enclosing block (thereby
-// position in the _allocate_list may need to be updated.  There are two
+// avoiding iteration over the _active_list).  Once the block has been
-// cases:
+// determined, its _allocated_bitmask needs to be updated, and its position in
+// the _allocate_list may need to be updated.  There are two cases:
 //
 // (a) If the block is neither full nor would become empty with the release of
 // the entry, only its _allocated_bitmask needs to be updated.  But if the CAS
 // update fails, the applicable case may change for the retry.
 //
-// (b) Otherwise, the _allocate_list will also need to be modified.  This
+// (b) Otherwise, the _allocate_list also needs to be modified.  This requires
-// requires locking the _allocate_mutex, and then attempting to CAS the
+// locking the _allocate_mutex.  To keep the release() operation lock-free,
-// _allocated_bitmask.  If the CAS fails, the applicable case may change for
+// rather than updating the _allocate_list itself, it instead performs a
-// the retry.  If the CAS succeeds, then update the _allocate_list according
+// lock-free push of the block onto the _deferred_updates list.  Entries on
-// to the the state changes.  If the block changed from full to not full, then
+// that list are processed by allocate() and delete_empty_blocks_XXX(), while
-// it needs to be added to the _allocate_list, for use in future allocations.
+// they already hold the necessary lock.  That processing makes the block's
-// If the block changed from not empty to empty, then it is moved to the end
+// list state consistent with its current _allocated_bitmask.  The block is
-// of the _allocate_list, for ease of empty block deletion processing.
+// added to the _allocate_list if not already present and the bitmask is not
+// full.  The block is moved to the end of the _allocated_list if the bitmask
+// is empty, for ease of empty block deletion processing.
 oop* OopStorage::allocate() {
 MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
+// Do some deferred update processing every time we allocate.
+// Continue processing deferred updates if _allocate_list is empty,
+// in the hope that we'll get a block from that, rather than
+// allocating a new block.
+while (reduce_deferred_updates() && (_allocate_list.head() == NULL)) {}
+// Use the first block in _allocate_list for the allocation.
 Block* block = _allocate_list.head();
 if (block == NULL) {
 // No available blocks; make a new one, and add to storage.
 {
 MutexUnlockerEx mul(_allocate_mutex, Mutex::_no_safepoint_check_flag);
 block = Block::new_block(this);
 }
-if (block != NULL) {
+if (block == NULL) {
+while (_allocate_list.head() == NULL) {
+if (!reduce_deferred_updates()) {
+// Failed to make new block, no other thread made a block
+// available while the mutex was released, and didn't get
+// one from a deferred update either, so return failure.
+log_info(oopstorage, ref)("%s: failed allocation", name());
+return NULL;
+}
+}
+} else {
 // Add new block to storage.
 log_info(oopstorage, blocks)("%s: new block " PTR_FORMAT, name(), p2i(block));
 // Add to end of _allocate_list.  The mutex release allowed
 // 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.
 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) {
+static void log_release_transitions(uintx releasing,
-assert(releasing != 0, "invariant");
+uintx old_allocated,
-uintx allocated = block.allocated_bitmask();
+const OopStorage* owner,
+const void* block) {
+ResourceMark rm;
+Log(oopstorage, blocks) log;
+LogStream ls(log.debug());
+if (is_full_bitmask(old_allocated)) {
+ls.print_cr("%s: block not full " PTR_FORMAT, owner->name(), p2i(block));
+}
+if (releasing == old_allocated) {
+ls.print_cr("%s: block empty " PTR_FORMAT, owner->name(), p2i(block));
+}
+}
+void OopStorage::Block::release_entries(uintx releasing, Block* volatile* deferred_list) {
+assert(releasing != 0, "preconditon");
+// Prevent empty block deletion when transitioning to empty.
+Atomic::inc(&_release_refcount);
+// Atomically update allocated bitmask.
+uintx old_allocated = _allocated_bitmask;
 while (true) {
-assert(releasing == (allocated & releasing), "invariant");
+assert((releasing & ~old_allocated) == 0, "releasing unallocated entries");
-uintx new_value = allocated ^ releasing;
+uintx new_value = old_allocated ^ releasing;
-// CAS new_value into block's allocated bitmask, retrying with
+uintx fetched = Atomic::cmpxchg(new_value, &_allocated_bitmask, old_allocated);
-// updated allocated bitmask until the CAS succeeds.
+if (fetched == old_allocated) break; // Successful update.
-uintx fetched;
+old_allocated = fetched;             // Retry with updated bitmask.
-if (!is_full_bitmask(allocated) && !is_empty_bitmask(new_value)) {
+}
-fetched = block.cmpxchg_allocated_bitmask(new_value, allocated);
-if (fetched == allocated) return;
+// Now that the bitmask has been updated, if we have a state transition
-} else {
+// (updated bitmask is empty or old bitmask was full), atomically push
-// Need special handling if transitioning from full to not full,
+// this block onto the deferred updates list.  Some future call to
-// or from not empty to empty.  For those cases, must hold the
+// reduce_deferred_updates will make any needed changes related to this
-// _allocation_mutex when updating the allocated bitmask, to
+// block and _allocate_list.  This deferral avoids list updates and the
-// ensure the associated list manipulations will be consistent
+// associated locking here.
-// with the allocation bitmask that is visible to other threads
+if ((releasing == old_allocated) || is_full_bitmask(old_allocated)) {
-// in allocate() or deleting empty blocks.
+// Log transitions.  Both transitions are possible in a single update.
-MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
+if (log_is_enabled(Debug, oopstorage, blocks)) {
-fetched = block.cmpxchg_allocated_bitmask(new_value, allocated);
+log_release_transitions(releasing, old_allocated, _owner, this);
-if (fetched == allocated) {
+}
-// CAS succeeded; handle special cases, which might no longer apply.
+// Attempt to claim responsibility for adding this block to the deferred
-if (is_full_bitmask(allocated)) {
+// list, by setting the link to non-NULL by self-looping.  If this fails,
-// Transitioning from full to not-full; add to _allocate_list.
+// then someone else has made such a claim and the deferred update has not
-log_debug(oopstorage, blocks)("%s: block not full " PTR_FORMAT, name(), p2i(&block));
+// yet been processed and will include our change, so we don't need to do
-_allocate_list.push_front(block);
+// anything further.
-assert(!block.is_full(), "invariant"); // Still not full.
+if (Atomic::replace_if_null(this, &_deferred_updates_next)) {
-}
+// Successfully claimed.  Push, with self-loop for end-of-list.
-if (is_empty_bitmask(new_value)) {
+Block* head = *deferred_list;
-// Transitioning from not-empty to empty; move to end of
+while (true) {
-// _allocate_list, to make it a deletion candidate.
+_deferred_updates_next = (head == NULL) ? this : head;
-log_debug(oopstorage, blocks)("%s: block empty " PTR_FORMAT, name(), p2i(&block));
+Block* fetched = Atomic::cmpxchg(this, deferred_list, head);
-_allocate_list.unlink(block);
+if (fetched == head) break; // Successful update.
-_allocate_list.push_back(block);
+head = fetched;             // Retry with updated head.
-++_empty_block_count;
-assert(block.is_empty(), "invariant"); // Still empty.
-}
-return;                 // Successful CAS and transitions handled.
 }
-}
+log_debug(oopstorage, blocks)("%s: deferred update " PTR_FORMAT,
-// CAS failed; retry with latest value.
+_owner->name(), p2i(this));
-allocated = fetched;
+}
 }
-}
+// Release hold on empty block deletion.
+Atomic::dec(&_release_refcount);
-#ifdef ASSERT
+}
-void OopStorage::check_release(const Block* block, const oop* ptr) const {
-switch (allocation_status_validating_block(block, ptr)) {
+// Process one available deferred update.  Returns true if one was processed.
-case INVALID_ENTRY:
+bool OopStorage::reduce_deferred_updates() {
-fatal("Releasing invalid entry: " PTR_FORMAT, p2i(ptr));
+assert_locked_or_safepoint(_allocate_mutex);
-break;
+// Atomically pop a block off the list, if any available.
+// No ABA issue because this is only called by one thread at a time.
-case UNALLOCATED_ENTRY:
+// The atomicity is wrto pushes by release().
-fatal("Releasing unallocated entry: " PTR_FORMAT, p2i(ptr));
+Block* block = OrderAccess::load_acquire(&_deferred_updates);
-break;
+while (true) {
+if (block == NULL) return false;
-case ALLOCATED_ENTRY:
+// Try atomic pop of block from list.
-assert(block->contains(ptr), "invariant");
+Block* tail = block->deferred_updates_next();
-break;
+if (block == tail) tail = NULL; // Handle self-loop end marker.
+Block* fetched = Atomic::cmpxchg(tail, &_deferred_updates, block);
-default:
+if (fetched == block) break; // Update successful.
-ShouldNotReachHere();
+block = fetched;             // Retry with updated block.
 }
-}
+block->set_deferred_updates_next(NULL); // Clear tail after updating head.
-#endif // ASSERT
+// Ensure bitmask read after pop is complete, including clearing tail, for
+// ordering with release().  Without this, we may be processing a stale
+// bitmask state here while blocking a release() operation from recording
+// the deferred update needed for its bitmask change.
+OrderAccess::storeload();
+// Process popped block.
+uintx allocated = block->allocated_bitmask();
+// Make membership in list consistent with bitmask state.
+if ((_allocate_list.ctail() != NULL) &&
+((_allocate_list.ctail() == block) ||
+(_allocate_list.next(*block) != NULL))) {
+// Block is in the allocate list.
+assert(!is_full_bitmask(allocated), "invariant");
+} else if (!is_full_bitmask(allocated)) {
+// Block is not in the allocate list, but now should be.
+_allocate_list.push_front(*block);
+} // Else block is full and not in list, which is correct.
+// Move empty block to end of list, for possible deletion.
+if (is_empty_bitmask(allocated)) {
+_allocate_list.unlink(*block);
+_allocate_list.push_back(*block);
+}
+log_debug(oopstorage, blocks)("%s: processed deferred update " PTR_FORMAT,
+name(), p2i(block));
+return true;              // Processed one pending update.
+}
 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);
+assert(block != NULL, "%s: invalid release " PTR_FORMAT, name(), p2i(ptr));
 log_info(oopstorage, ref)("%s: released " PTR_FORMAT, name(), p2i(ptr));
-release_from_block(*block, block->bitmask_for_entry(ptr));
+block->release_entries(block->bitmask_for_entry(ptr), &_deferred_updates);
 Atomic::dec(&_allocation_count);
 }
 void OopStorage::release(const oop* const* ptrs, size_t size) {
 size_t i = 0;
 while (i < size) {
 check_release_entry(ptrs[i]);
 Block* block = find_block_or_null(ptrs[i]);
-check_release(block, ptrs[i]);
+assert(block != NULL, "%s: invalid release " PTR_FORMAT, name(), p2i(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];
+check_release_entry(entry);
 // 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);
+block->release_entries(releasing, &_deferred_updates);
 Atomic::sub(count, &_allocation_count);
 }
 }
 const char* dup_name(const char* name) {
 Mutex* active_mutex) :
 _name(dup_name(name)),
 _active_list(&Block::get_active_entry),
 _allocate_list(&Block::get_allocate_entry),
 _active_head(NULL),
+_deferred_updates(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,
 Block::delete_block(block);
 }
 OopStorage::~OopStorage() {
 Block* block;
+while ((block = _deferred_updates) != NULL) {
+_deferred_updates = block->deferred_updates_next();
+block->set_deferred_updates_next(NULL);
+}
 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) {
+void OopStorage::delete_empty_blocks_safepoint() {
 assert_at_safepoint();
+// Process any pending release updates, which may make more empty
+// blocks available for deletion.
+while (reduce_deferred_updates()) {}
 // Don't interfere with a concurrent iteration.
 if (_concurrent_iteration_active) return;
-// Compute the number of blocks to remove, to minimize volatile accesses.
+// Delete empty (and otherwise deletable) blocks from end of _allocate_list.
-size_t empty_blocks = _empty_block_count;
+for (const Block* block = _allocate_list.ctail();
-if (retain < empty_blocks) {
+(block != NULL) && block->is_deletable();
-size_t remove_count = empty_blocks - retain;
+block = _allocate_list.ctail()) {
-// Update volatile counters once.
+_active_list.unlink(*block);
-_block_count -= remove_count;
+_allocate_list.unlink(*block);
-_empty_block_count -= remove_count;
+delete_empty_block(*block);
-do {
+--_block_count;
-const Block* block = _allocate_list.ctail();
+}
-assert(block != NULL, "invariant");
+// Update _active_head, in case current value was in deleted set.
-assert(block->is_empty(), "invariant");
+_active_head = _active_list.head();
-// Remove block from lists, and delete it.
+}
-_active_list.unlink(*block);
-_allocate_list.unlink(*block);
+void OopStorage::delete_empty_blocks_concurrent() {
-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 = _block_count;
-size_t limit = _empty_block_count - retain;
-for (size_t i = 0; (i < limit) && (retain < _empty_block_count); ++i) {
+for (size_t i = 0; i < limit; ++i) {
+// Additional updates might become available while we dropped the
+// lock.  But limit number processed to limit lock duration.
+reduce_deferred_updates();
 const Block* block = _allocate_list.ctail();
-assert(block != NULL, "invariant");
+if ((block == NULL) || !block->is_deletable()) {
-assert(block->is_empty(), "invariant");
+// No block to delete, so done.  There could be more pending
+// deferred updates that could give us more work to do; deal with
+// that in some later call, to limit lock duration here.
+return;
+}
 {
 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_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);
+const Block* block = find_block_or_null(ptr);
+if (block != NULL) {
+// Verify block is a real block.  For now, simple linear search.
+// Do something more clever if this is a performance bottleneck.
+MutexLockerEx ml(_allocate_mutex, Mutex::_no_safepoint_check_flag);
+for (const Block* check_block = _active_list.chead();
+check_block != NULL;
+check_block = _active_list.next(*check_block)) {
+if (check_block == block) {
+if ((block->allocated_bitmask() & block->bitmask_for_entry(ptr)) != 0) {
+return ALLOCATED_ENTRY;
+} else {
+return UNALLOCATED_ENTRY;
+}
+}
+}
+}
+return INVALID_ENTRY;
 }
 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;
 #ifndef PRODUCT
 void OopStorage::print_on(outputStream* st) const {
 size_t allocations = _allocation_count;
 size_t blocks = _block_count;
-size_t empties = _empty_block_count;
-// Comparison is being careful about racy accesses.
-size_t used = (blocks < empties) ? 0 : (blocks - empties);
 double data_size = section_size * section_count;
-double alloc_percentage = percent_of((double)allocations, used * data_size);
+double alloc_percentage = percent_of((double)allocations, blocks * data_size);
-st->print("%s: " SIZE_FORMAT " entries in " SIZE_FORMAT " blocks (%.F%%), "
+st->print("%s: " SIZE_FORMAT " entries in " SIZE_FORMAT " blocks (%.F%%), " SIZE_FORMAT " bytes",
-SIZE_FORMAT " empties, " SIZE_FORMAT " bytes",
+name(), allocations, blocks, alloc_percentage, total_memory_usage());
-name(), allocations, used, alloc_percentage,
-empties, total_memory_usage());
 if (_concurrent_iteration_active) {
 st->print(", concurrent iteration active");
 }
 }

changeset 48886	e1d09bd56d2d
parent 48816	3495d6050efe
child 49333	489f1dd40582