1 /*
   2  * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #include "precompiled.hpp"
  25 
  26 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
  27 #include "gc/shenandoah/shenandoahSATBMarkQueueSet.hpp"
  28 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
  29 
  30 ShenandoahSATBMarkQueueSet::ShenandoahSATBMarkQueueSet() :
  31   _heap(NULL),
  32   _satb_mark_queue_buffer_allocator("SATB Buffer Allocator", ShenandoahSATBBufferSize)
  33 {}
  34 
  35 void ShenandoahSATBMarkQueueSet::initialize(ShenandoahHeap* const heap,
  36                                             Monitor* cbl_mon,
  37                                             int process_completed_threshold,
  38                                             uint buffer_enqueue_threshold_percentage,
  39                                             Mutex* lock) {
  40   SATBMarkQueueSet::initialize(cbl_mon,
  41                                &_satb_mark_queue_buffer_allocator,
  42                                process_completed_threshold,
  43                                buffer_enqueue_threshold_percentage,
  44                                lock);
  45   _heap = heap;
  46 }
  47 
  48 SATBMarkQueue& ShenandoahSATBMarkQueueSet::satb_queue_for_thread(JavaThread* const t) const {
  49   return ShenandoahThreadLocalData::satb_mark_queue(t);
  50 }
  51 
  52 template <bool RESOLVE>
  53 class ShenandoahSATBMarkQueueFilterFn {
  54   ShenandoahHeap* const _heap;
  55 
  56 public:
  57   ShenandoahSATBMarkQueueFilterFn(ShenandoahHeap* heap) : _heap(heap) {}
  58 
  59   // Return true if entry should be filtered out (removed), false if
  60   // it should be retained.
  61   bool operator()(const void* entry) const {
  62     return !_heap->requires_marking<RESOLVE>(entry);
  63   }
  64 };
  65 
  66 void ShenandoahSATBMarkQueueSet::filter(SATBMarkQueue* queue) {
  67   assert(_heap != NULL, "SATB queue set not initialized");
  68   if (_heap->has_forwarded_objects()) {
  69     apply_filter(ShenandoahSATBMarkQueueFilterFn<true>(_heap), queue);
  70   } else {
  71     apply_filter(ShenandoahSATBMarkQueueFilterFn<false>(_heap), queue);
  72   }
  73 }
  74 
  75 bool ShenandoahSATBMarkQueue::should_enqueue_buffer() {
  76   bool should_enqueue = SATBMarkQueue::should_enqueue_buffer();
  77   size_t cap = capacity();
  78   Thread* t = Thread::current();
  79   if (ShenandoahThreadLocalData::is_force_satb_flush(t)) {
  80     if (!should_enqueue && cap != index()) {
  81       // Non-empty buffer is compacted, and we decided not to enqueue it.
  82       // We still want to know about leftover work in that buffer eventually.
  83       // This avoid dealing with these leftovers during the final-mark, after
  84       // the buffers are drained completely. See JDK-8205353 for more discussion.
  85       should_enqueue = true;
  86     }
  87     ShenandoahThreadLocalData::set_force_satb_flush(t, false);
  88   }
  89   return should_enqueue;
  90 }