/* * Copyright (c) 2001, 2016, 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 "gc/g1/dirtyCardQueue.hpp" #include "gc/g1/g1CollectedHeap.inline.hpp" #include "gc/g1/heapRegionRemSet.hpp" #include "gc/shared/workgroup.hpp" #include "runtime/atomic.inline.hpp" #include "runtime/mutexLocker.hpp" #include "runtime/safepoint.hpp" #include "runtime/thread.inline.hpp" // Represents a set of free small integer ids. class FreeIdSet : public CHeapObj { enum { end_of_list = UINT_MAX, claimed = UINT_MAX - 1 }; uint _size; Monitor* _mon; uint* _ids; uint _hd; uint _waiters; uint _claimed; public: FreeIdSet(uint size, Monitor* mon); ~FreeIdSet(); // Returns an unclaimed parallel id (waiting for one to be released if // necessary). uint claim_par_id(); void release_par_id(uint id); }; FreeIdSet::FreeIdSet(uint size, Monitor* mon) : _size(size), _mon(mon), _hd(0), _waiters(0), _claimed(0) { guarantee(size != 0, "must be"); _ids = NEW_C_HEAP_ARRAY(uint, size, mtGC); for (uint i = 0; i < size - 1; i++) { _ids[i] = i+1; } _ids[size-1] = end_of_list; // end of list. } FreeIdSet::~FreeIdSet() { FREE_C_HEAP_ARRAY(uint, _ids); } uint FreeIdSet::claim_par_id() { MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); while (_hd == end_of_list) { _waiters++; _mon->wait(Mutex::_no_safepoint_check_flag); _waiters--; } uint res = _hd; _hd = _ids[res]; _ids[res] = claimed; // For debugging. _claimed++; return res; } void FreeIdSet::release_par_id(uint id) { MutexLockerEx x(_mon, Mutex::_no_safepoint_check_flag); assert(_ids[id] == claimed, "Precondition."); _ids[id] = _hd; _hd = id; _claimed--; if (_waiters > 0) { _mon->notify_all(); } } DirtyCardQueue::DirtyCardQueue(DirtyCardQueueSet* qset, bool permanent) : // Dirty card queues are always active, so we create them with their // active field set to true. PtrQueue(qset, permanent, true /* active */) { } DirtyCardQueue::~DirtyCardQueue() { if (!is_permanent()) { flush(); } } DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) : PtrQueueSet(notify_when_complete), _mut_process_closure(NULL), _shared_dirty_card_queue(this, true /* permanent */), _free_ids(NULL), _processed_buffers_mut(0), _processed_buffers_rs_thread(0) { _all_active = true; } // Determines how many mutator threads can process the buffers in parallel. uint DirtyCardQueueSet::num_par_ids() { return (uint)os::processor_count(); } void DirtyCardQueueSet::initialize(CardTableEntryClosure* cl, Monitor* cbl_mon, Mutex* fl_lock, int process_completed_threshold, int max_completed_queue, Mutex* lock, DirtyCardQueueSet* fl_owner, bool init_free_ids) { _mut_process_closure = cl; PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold, max_completed_queue, fl_owner); set_buffer_size(G1UpdateBufferSize); _shared_dirty_card_queue.set_lock(lock); if (init_free_ids) { _free_ids = new FreeIdSet(num_par_ids(), _cbl_mon); } } void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) { t->dirty_card_queue().handle_zero_index(); } bool DirtyCardQueueSet::apply_closure_to_buffer(CardTableEntryClosure* cl, BufferNode* node, bool consume, uint worker_i) { if (cl == NULL) return true; bool result = true; void** buf = BufferNode::make_buffer_from_node(node); size_t limit = DirtyCardQueue::byte_index_to_index(buffer_size()); size_t i = DirtyCardQueue::byte_index_to_index(node->index()); for ( ; i < limit; ++i) { jbyte* card_ptr = static_cast(buf[i]); assert(card_ptr != NULL, "invariant"); if (!cl->do_card_ptr(card_ptr, worker_i)) { result = false; // Incomplete processing. break; } } if (consume) { size_t new_index = DirtyCardQueue::index_to_byte_index(i); assert(new_index <= buffer_size(), "invariant"); node->set_index(new_index); } return result; } inline void assert_fully_consumed(BufferNode* node, size_t buffer_size) { assert(node->index() == buffer_size, "Buffer was not fully consumed as claimed: index: " SIZE_FORMAT ", size: " SIZE_FORMAT, node->index(), buffer_size); } bool DirtyCardQueueSet::mut_process_buffer(BufferNode* node) { guarantee(_free_ids != NULL, "must be"); uint worker_i = _free_ids->claim_par_id(); // temporarily claim an id bool result = apply_closure_to_buffer(_mut_process_closure, node, true, worker_i); _free_ids->release_par_id(worker_i); // release the id if (result) { assert_fully_consumed(node, buffer_size()); Atomic::inc(&_processed_buffers_mut); } return result; } BufferNode* DirtyCardQueueSet::get_completed_buffer(size_t stop_at) { BufferNode* nd = NULL; MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); if (_n_completed_buffers <= stop_at) { _process_completed = false; return NULL; } if (_completed_buffers_head != NULL) { nd = _completed_buffers_head; assert(_n_completed_buffers > 0, "Invariant"); _completed_buffers_head = nd->next(); _n_completed_buffers--; if (_completed_buffers_head == NULL) { assert(_n_completed_buffers == 0, "Invariant"); _completed_buffers_tail = NULL; } } DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); return nd; } bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl, uint worker_i, size_t stop_at, bool during_pause) { assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause"); BufferNode* nd = get_completed_buffer(stop_at); if (nd == NULL) { return false; } else { if (apply_closure_to_buffer(cl, nd, true, worker_i)) { assert_fully_consumed(nd, buffer_size()); // Done with fully processed buffer. deallocate_buffer(nd); Atomic::inc(&_processed_buffers_rs_thread); } else { // Return partially processed buffer to the queue. guarantee(!during_pause, "Should never stop early"); enqueue_complete_buffer(nd); } return true; } } void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) { BufferNode* nd = _cur_par_buffer_node; while (nd != NULL) { BufferNode* next = nd->next(); void* actual = Atomic::cmpxchg_ptr(next, &_cur_par_buffer_node, nd); if (actual == nd) { bool b = apply_closure_to_buffer(cl, nd, false); guarantee(b, "Should not stop early."); nd = next; } else { nd = static_cast(actual); } } } // Deallocates any completed log buffers void DirtyCardQueueSet::clear() { BufferNode* buffers_to_delete = NULL; { MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); while (_completed_buffers_head != NULL) { BufferNode* nd = _completed_buffers_head; _completed_buffers_head = nd->next(); nd->set_next(buffers_to_delete); buffers_to_delete = nd; } _n_completed_buffers = 0; _completed_buffers_tail = NULL; DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); } while (buffers_to_delete != NULL) { BufferNode* nd = buffers_to_delete; buffers_to_delete = nd->next(); deallocate_buffer(nd); } } void DirtyCardQueueSet::abandon_logs() { assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); clear(); // Since abandon is done only at safepoints, we can safely manipulate // these queues. for (JavaThread* t = Threads::first(); t; t = t->next()) { t->dirty_card_queue().reset(); } shared_dirty_card_queue()->reset(); } void DirtyCardQueueSet::concatenate_log(DirtyCardQueue& dcq) { if (!dcq.is_empty()) { enqueue_complete_buffer( BufferNode::make_node_from_buffer(dcq.get_buf(), dcq.get_index())); dcq.reinitialize(); } } void DirtyCardQueueSet::concatenate_logs() { // Iterate over all the threads, if we find a partial log add it to // the global list of logs. Temporarily turn off the limit on the number // of outstanding buffers. int save_max_completed_queue = _max_completed_queue; _max_completed_queue = max_jint; assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); for (JavaThread* t = Threads::first(); t; t = t->next()) { concatenate_log(t->dirty_card_queue()); } concatenate_log(_shared_dirty_card_queue); // Restore the completed buffer queue limit. _max_completed_queue = save_max_completed_queue; }