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 /*

  * 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_implementation/g1/dirtyCardQueue.hpp"

 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

 #include "gc_implementation/g1/heapRegionRemSet.hpp"

 #include "runtime/atomic.hpp"

 #include "runtime/mutexLocker.hpp"

 #include "runtime/safepoint.hpp"

 #include "runtime/thread.inline.hpp"

 #include "utilities/workgroup.hpp"

 bool DirtyCardQueue::apply_closure(CardTableEntryClosure* cl,

                                    bool consume,

                                    uint worker_i) {

   bool res = true;

   if (_buf != NULL) {

     res = apply_closure_to_buffer(cl, _buf, _index, _sz,

                                   consume,

                                   worker_i);

     if (res && consume) _index = _sz;

   }

   return res;

 }

 bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,

                                              void** buf,

                                              size_t index, size_t sz,

                                              bool consume,

                                              uint worker_i) {

   if (cl == NULL) return true;

   for (size_t i = index; i < sz; i += oopSize) {

     int ind = byte_index_to_index((int)i);

     jbyte* card_ptr = (jbyte*)buf[ind];

     if (card_ptr != NULL) {

       // Set the entry to null, so we don't do it again (via the test

       // above) if we reconsider this buffer.

       if (consume) buf[ind] = NULL;

       if (!cl->do_card_ptr(card_ptr, worker_i)) return false;

     }

   }

   return true;

 }

 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away

 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list

 #endif // _MSC_VER

 DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :

   PtrQueueSet(notify_when_complete),

   _mut_process_closure(NULL),

   _shared_dirty_card_queue(this, true /*perm*/),

   _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(CardTableEntryClosure* cl, Monitor* cbl_mon, Mutex* fl_lock,

                                    int process_completed_threshold,

                                    int max_completed_queue,

                                    Mutex* lock, PtrQueueSet* fl_owner) {

   _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);

   _free_ids = new FreeIdSet((int) num_par_ids(), _cbl_mon);

 }

 void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {

   t->dirty_card_queue().handle_zero_index();

 }

 void DirtyCardQueueSet::iterate_closure_all_threads(CardTableEntryClosure* cl,

                                                     bool consume,

                                                     uint worker_i) {

   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");

   for(JavaThread* t = Threads::first(); t; t = t->next()) {

     bool b = t->dirty_card_queue().apply_closure(cl, consume);

     guarantee(b, "Should not be interrupted.");

   }

   bool b = shared_dirty_card_queue()->apply_closure(cl,

                                                     consume,

                                                     worker_i);

   guarantee(b, "Should not be interrupted.");

 }

 bool DirtyCardQueueSet::mut_process_buffer(void** buf) {

   // Used to determine if we had already claimed a par_id

   // before entering this method.

   bool already_claimed = false;

   // We grab the current JavaThread.

   JavaThread* thread = JavaThread::current();

   // We get the the number of any par_id that this thread

   // might have already claimed.

   uint worker_i = thread->get_claimed_par_id();

   // If worker_i is not UINT_MAX then the thread has already claimed

   // a par_id. We make note of it using the already_claimed value

   if (worker_i != UINT_MAX) {

     already_claimed = true;

   } else {

     // Otherwise we need to claim a par id

     worker_i = _free_ids->claim_par_id();

     // And store the par_id value in the thread

     thread->set_claimed_par_id(worker_i);

   }

   bool b = false;

   if (worker_i != UINT_MAX) {

     b = DirtyCardQueue::apply_closure_to_buffer(_mut_process_closure, buf, 0,

                                                 _sz, true, worker_i);

     if (b) Atomic::inc(&_processed_buffers_mut);

     // If we had not claimed an id before entering the method

     // then we must release the id.

     if (!already_claimed) {

       // we release the id

       _free_ids->release_par_id(worker_i);

       // and set the claimed_id in the thread to UINT_MAX

       thread->set_claimed_par_id(UINT_MAX);

     }

   }

   return b;

 }

 BufferNode*

 DirtyCardQueueSet::get_completed_buffer(int stop_at) {

   BufferNode* nd = NULL;

   MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);

   if ((int)_n_completed_buffers <= stop_at) {

     _process_completed = false;

     return NULL;

   }

   if (_completed_buffers_head != NULL) {

     nd = _completed_buffers_head;

     _completed_buffers_head = nd->next();

     if (_completed_buffers_head == NULL)

       _completed_buffers_tail = NULL;

     _n_completed_buffers--;

     assert(_n_completed_buffers >= 0, "Invariant");

   }

   debug_only(assert_completed_buffer_list_len_correct_locked());

   return nd;

 }

 bool DirtyCardQueueSet::

 apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,

                                          uint worker_i,

                                          BufferNode* nd) {

   if (nd != NULL) {

     void **buf = BufferNode::make_buffer_from_node(nd);

     size_t index = nd->index();

     bool b =

       DirtyCardQueue::apply_closure_to_buffer(cl, buf,

                                               index, _sz,

                                               true, worker_i);

     if (b) {

       deallocate_buffer(buf);

       return true;  // In normal case, go on to next buffer.

     } else {

       enqueue_complete_buffer(buf, index);

       return false;

     }

   } else {

     return false;

   }

 }

 bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,

                                                           uint worker_i,

                                                           int 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);

   bool res = apply_closure_to_completed_buffer_helper(cl, worker_i, nd);

   if (res) Atomic::inc(&_processed_buffers_rs_thread);

   return res;

 }

 void DirtyCardQueueSet::apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {

   BufferNode* nd = _completed_buffers_head;

   while (nd != NULL) {

     bool b =

       DirtyCardQueue::apply_closure_to_buffer(cl,

                                               BufferNode::make_buffer_from_node(nd),

                                               0, _sz, false);

     guarantee(b, "Should not stop early.");

     nd = nd->next();

   }

 }

 void DirtyCardQueueSet::par_apply_closure_to_all_completed_buffers(CardTableEntryClosure* cl) {

   BufferNode* nd = _cur_par_buffer_node;

   while (nd != NULL) {

     BufferNode* next = (BufferNode*)nd->next();

     BufferNode* actual = (BufferNode*)Atomic::cmpxchg_ptr((void*)next, (volatile void*)&_cur_par_buffer_node, (void*)nd);

     if (actual == nd) {

       bool b =

         DirtyCardQueue::apply_closure_to_buffer(cl,

                                                 BufferNode::make_buffer_from_node(actual),

                                                 0, _sz, false);

       guarantee(b, "Should not stop early.");

       nd = next;

     } else {

       nd = 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(BufferNode::make_buffer_from_node(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_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()) {

     DirtyCardQueue& dcq = t->dirty_card_queue();

     if (dcq.size() != 0) {

       void **buf = t->dirty_card_queue().get_buf();

       // We must NULL out the unused entries, then enqueue.

       for (size_t i = 0; i < t->dirty_card_queue().get_index(); i += oopSize) {

         buf[PtrQueue::byte_index_to_index((int)i)] = NULL;

       }

       enqueue_complete_buffer(dcq.get_buf(), dcq.get_index());

       dcq.reinitialize();

     }

   }

   if (_shared_dirty_card_queue.size() != 0) {

     enqueue_complete_buffer(_shared_dirty_card_queue.get_buf(),

                             _shared_dirty_card_queue.get_index());

     _shared_dirty_card_queue.reinitialize();

   }

   // Restore the completed buffer queue limit.

   _max_completed_queue = save_max_completed_queue;

 }