--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/hotspot/share/gc/g1/dirtyCardQueue.cpp Tue Sep 12 19:03:39 2017 +0200
@@ -0,0 +1,347 @@
+/*
+ * Copyright (c) 2001, 2017, 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/g1RemSet.hpp"
+#include "gc/g1/heapRegionRemSet.hpp"
+#include "gc/shared/workgroup.hpp"
+#include "runtime/atomic.hpp"
+#include "runtime/mutexLocker.hpp"
+#include "runtime/safepoint.hpp"
+#include "runtime/thread.inline.hpp"
+
+// Closure used for updating remembered sets and recording references that
+// point into the collection set while the mutator is running.
+// Assumed to be only executed concurrently with the mutator. Yields via
+// SuspendibleThreadSet after every card.
+class G1RefineCardConcurrentlyClosure: public CardTableEntryClosure {
+public:
+ bool do_card_ptr(jbyte* card_ptr, uint worker_i) {
+ G1CollectedHeap::heap()->g1_rem_set()->refine_card_concurrently(card_ptr, worker_i);
+
+ if (SuspendibleThreadSet::should_yield()) {
+ // Caller will actually yield.
+ return false;
+ }
+ // Otherwise, we finished successfully; return true.
+ return true;
+ }
+};
+
+// Represents a set of free small integer ids.
+class FreeIdSet : public CHeapObj<mtGC> {
+ 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),
+ _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::initial_active_processor_count();
+}
+
+void DirtyCardQueueSet::initialize(Monitor* cbl_mon,
+ Mutex* fl_lock,
+ int process_completed_threshold,
+ int max_completed_queue,
+ Mutex* lock,
+ DirtyCardQueueSet* fl_owner,
+ bool init_free_ids) {
+ 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 i = node->index();
+ size_t limit = buffer_size();
+ for ( ; i < limit; ++i) {
+ jbyte* card_ptr = static_cast<jbyte*>(buf[i]);
+ assert(card_ptr != NULL, "invariant");
+ if (!cl->do_card_ptr(card_ptr, worker_i)) {
+ result = false; // Incomplete processing.
+ break;
+ }
+ }
+ if (consume) {
+ assert(i <= buffer_size(), "invariant");
+ node->set_index(i);
+ }
+ return result;
+}
+
+#ifndef ASSERT
+#define assert_fully_consumed(node, buffer_size)
+#else
+#define assert_fully_consumed(node, buffer_size) \
+ do { \
+ size_t _afc_index = (node)->index(); \
+ size_t _afc_size = (buffer_size); \
+ assert(_afc_index == _afc_size, \
+ "Buffer was not fully consumed as claimed: index: " \
+ SIZE_FORMAT ", size: " SIZE_FORMAT, \
+ _afc_index, _afc_size); \
+ } while (0)
+#endif // ASSERT
+
+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
+ G1RefineCardConcurrentlyClosure cl;
+ bool result = apply_closure_to_buffer(&cl, 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::refine_completed_buffer_concurrently(uint worker_i, size_t stop_at) {
+ G1RefineCardConcurrentlyClosure cl;
+ return apply_closure_to_completed_buffer(&cl, worker_i, stop_at, false);
+}
+
+bool DirtyCardQueueSet::apply_closure_during_gc(CardTableEntryClosure* cl, uint worker_i) {
+ assert_at_safepoint(false);
+ return apply_closure_to_completed_buffer(cl, worker_i, 0, true);
+}
+
+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<BufferNode*>(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()) {
+ dcq.flush();
+ }
+}
+
+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;
+}