1 /*
   2  * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 #include "precompiled.hpp"
  26 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
  27 #include "gc_implementation/g1/heapRegion.hpp"
  28 #include "gc_implementation/g1/satbQueue.hpp"
  29 #include "runtime/mutexLocker.hpp"
  30 #include "runtime/thread.inline.hpp"
  31 
  32 G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(MemRegion whole_heap,
  33                                                  int max_covered_regions) :
  34     CardTableModRefBSForCTRS(whole_heap, max_covered_regions)
  35 {
  36   _kind = G1SATBCT;
  37 }
  38 
  39 
  40 void G1SATBCardTableModRefBS::enqueue(oop pre_val) {
  41   // Nulls should have been already filtered.
  42   assert(pre_val->is_oop(true), "Error");
  43 
  44   if (!JavaThread::satb_mark_queue_set().is_active()) return;
  45   Thread* thr = Thread::current();
  46   if (thr->is_Java_thread()) {
  47     JavaThread* jt = (JavaThread*)thr;
  48     jt->satb_mark_queue().enqueue(pre_val);
  49   } else {
  50     MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);
  51     JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);
  52   }
  53 }
  54 
  55 template <class T> void
  56 G1SATBCardTableModRefBS::write_ref_array_pre_work(T* dst, int count) {
  57   if (!JavaThread::satb_mark_queue_set().is_active()) return;
  58   T* elem_ptr = dst;
  59   for (int i = 0; i < count; i++, elem_ptr++) {
  60     T heap_oop = oopDesc::load_heap_oop(elem_ptr);
  61     if (!oopDesc::is_null(heap_oop)) {
  62       enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
  63     }
  64   }
  65 }
  66 
  67 bool G1SATBCardTableModRefBS::mark_card_deferred(size_t card_index) {
  68   jbyte val = _byte_map[card_index];
  69   // It's already processed
  70   if ((val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val()) {
  71     return false;
  72   }
  73 
  74   if  (val == g1_young_gen) {
  75     // the card is for a young gen region. We don't need to keep track of all pointers into young
  76     return false;
  77   }
  78 
  79   // Cached bit can be installed either on a clean card or on a claimed card.
  80   jbyte new_val = val;
  81   if (val == clean_card_val()) {
  82     new_val = (jbyte)deferred_card_val();
  83   } else {
  84     if (val & claimed_card_val()) {
  85       new_val = val | (jbyte)deferred_card_val();
  86     }
  87   }
  88   if (new_val != val) {
  89     Atomic::cmpxchg(new_val, &_byte_map[card_index], val);
  90   }
  91   return true;
  92 }
  93 
  94 void G1SATBCardTableModRefBS::g1_mark_as_young(const MemRegion& mr) {
  95   jbyte *const first = byte_for(mr.start());
  96   jbyte *const last = byte_after(mr.last());
  97 
  98   memset(first, g1_young_gen, last - first);
  99 }
 100 
 101 #ifndef PRODUCT
 102 void G1SATBCardTableModRefBS::verify_g1_young_region(MemRegion mr) {
 103   verify_region(mr, g1_young_gen,  true);
 104 }
 105 #endif
 106 
 107 G1SATBCardTableLoggingModRefBS::
 108 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap,
 109                                int max_covered_regions) :
 110   G1SATBCardTableModRefBS(whole_heap, max_covered_regions),
 111   _dcqs(JavaThread::dirty_card_queue_set())
 112 {
 113   _kind = G1SATBCTLogging;
 114 }
 115 
 116 void
 117 G1SATBCardTableLoggingModRefBS::write_ref_field_work(void* field,
 118                                                      oop new_val) {
 119   volatile jbyte* byte = byte_for(field);
 120   if (*byte == g1_young_gen) {
 121     return;
 122   }
 123   OrderAccess::storeload();
 124   if (*byte != dirty_card) {
 125     *byte = dirty_card;
 126     Thread* thr = Thread::current();
 127     if (thr->is_Java_thread()) {
 128       JavaThread* jt = (JavaThread*)thr;
 129       jt->dirty_card_queue().enqueue(byte);
 130     } else {
 131       MutexLockerEx x(Shared_DirtyCardQ_lock,
 132                       Mutex::_no_safepoint_check_flag);
 133       _dcqs.shared_dirty_card_queue()->enqueue(byte);
 134     }
 135   }
 136 }
 137 
 138 void
 139 G1SATBCardTableLoggingModRefBS::write_ref_field_static(void* field,
 140                                                        oop new_val) {
 141   uintptr_t field_uint = (uintptr_t)field;
 142   uintptr_t new_val_uint = (uintptr_t)new_val;
 143   uintptr_t comb = field_uint ^ new_val_uint;
 144   comb = comb >> HeapRegion::LogOfHRGrainBytes;
 145   if (comb == 0) return;
 146   if (new_val == NULL) return;
 147   // Otherwise, log it.
 148   G1SATBCardTableLoggingModRefBS* g1_bs =
 149     (G1SATBCardTableLoggingModRefBS*)Universe::heap()->barrier_set();
 150   g1_bs->write_ref_field_work(field, new_val);
 151 }
 152 
 153 void
 154 G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr, bool whole_heap) {
 155   volatile jbyte* byte = byte_for(mr.start());
 156   jbyte* last_byte = byte_for(mr.last());
 157   Thread* thr = Thread::current();
 158   if (whole_heap) {
 159     while (byte <= last_byte) {
 160       *byte = dirty_card;
 161       byte++;
 162     }
 163   } else {
 164     // skip all consecutive young cards
 165     for (; byte <= last_byte && *byte == g1_young_gen; byte++);
 166 
 167     if (byte <= last_byte) {
 168       OrderAccess::storeload();
 169       // Enqueue if necessary.
 170       if (thr->is_Java_thread()) {
 171         JavaThread* jt = (JavaThread*)thr;
 172         for (; byte <= last_byte; byte++) {
 173           if (*byte == g1_young_gen) {
 174             continue;
 175           }
 176           if (*byte != dirty_card) {
 177             *byte = dirty_card;
 178             jt->dirty_card_queue().enqueue(byte);
 179           }
 180         }
 181       } else {
 182         MutexLockerEx x(Shared_DirtyCardQ_lock,
 183                         Mutex::_no_safepoint_check_flag);
 184         for (; byte <= last_byte; byte++) {
 185           if (*byte == g1_young_gen) {
 186             continue;
 187           }
 188           if (*byte != dirty_card) {
 189             *byte = dirty_card;
 190             _dcqs.shared_dirty_card_queue()->enqueue(byte);
 191           }
 192         }
 193       }
 194     }
 195   }
 196 }