1 /*
   2  * Copyright (c) 2001, 2019, 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/g1/g1BarrierSet.inline.hpp"
  27 #include "gc/g1/g1BarrierSetAssembler.hpp"
  28 #include "gc/g1/g1CardTable.inline.hpp"
  29 #include "gc/g1/g1CollectedHeap.inline.hpp"
  30 #include "gc/g1/g1SATBMarkQueueSet.hpp"
  31 #include "gc/g1/g1ThreadLocalData.hpp"
  32 #include "gc/g1/heapRegion.hpp"
  33 #include "gc/shared/satbMarkQueue.hpp"
  34 #include "logging/log.hpp"
  35 #include "oops/access.inline.hpp"
  36 #include "oops/compressedOops.inline.hpp"
  37 #include "oops/oop.inline.hpp"
  38 #include "runtime/interfaceSupport.inline.hpp"
  39 #include "runtime/mutexLocker.hpp"
  40 #include "runtime/thread.inline.hpp"
  41 #include "utilities/macros.hpp"
  42 #ifdef COMPILER1
  43 #include "gc/g1/c1/g1BarrierSetC1.hpp"
  44 #endif
  45 #ifdef COMPILER2
  46 #include "gc/g1/c2/g1BarrierSetC2.hpp"
  47 #endif
  48 
  49 class G1BarrierSetC1;
  50 class G1BarrierSetC2;
  51 
  52 G1BarrierSet::G1BarrierSet(G1CardTable* card_table) :
  53   CardTableBarrierSet(make_barrier_set_assembler<G1BarrierSetAssembler>(),
  54                       make_barrier_set_c1<G1BarrierSetC1>(),
  55                       make_barrier_set_c2<G1BarrierSetC2>(),
  56                       card_table,
  57                       BarrierSet::FakeRtti(BarrierSet::G1BarrierSet)),
  58   _satb_mark_queue_buffer_allocator("SATB Buffer Allocator", G1SATBBufferSize),
  59   _dirty_card_queue_buffer_allocator("DC Buffer Allocator", G1UpdateBufferSize),
  60   _satb_mark_queue_set(),
  61   _dirty_card_queue_set()
  62 {}
  63 
  64 void G1BarrierSet::enqueue(oop pre_val) {
  65   // Nulls should have been already filtered.
  66   assert(oopDesc::is_oop(pre_val, true), "Error");
  67   G1ThreadLocalData::satb_mark_queue(Thread::current()).enqueue(pre_val);
  68 }
  69 
  70 template <class T> void
  71 G1BarrierSet::write_ref_array_pre_work(T* dst, size_t count) {
  72   if (!_satb_mark_queue_set.is_active()) return;
  73   T* elem_ptr = dst;
  74   for (size_t i = 0; i < count; i++, elem_ptr++) {
  75     T heap_oop = RawAccess<>::oop_load(elem_ptr);
  76     if (!CompressedOops::is_null(heap_oop)) {
  77       enqueue(CompressedOops::decode_not_null(heap_oop));
  78     }
  79   }
  80 }
  81 
  82 void G1BarrierSet::write_ref_array_pre(oop* dst, size_t count, bool dest_uninitialized) {
  83   if (!dest_uninitialized) {
  84     write_ref_array_pre_work(dst, count);
  85   }
  86 }
  87 
  88 void G1BarrierSet::write_ref_array_pre(narrowOop* dst, size_t count, bool dest_uninitialized) {
  89   if (!dest_uninitialized) {
  90     write_ref_array_pre_work(dst, count);
  91   }
  92 }
  93 
  94 void G1BarrierSet::write_ref_field_post_slow(volatile CardValue* byte) {
  95   // In the slow path, we know a card is not young
  96   assert(*byte != G1CardTable::g1_young_card_val(), "slow path invoked without filtering");
  97   OrderAccess::storeload();
  98   if (*byte != G1CardTable::dirty_card_val()) {
  99     *byte = G1CardTable::dirty_card_val();
 100     Thread* thr = Thread::current();
 101     G1ThreadLocalData::dirty_card_queue(thr).enqueue(byte);
 102   }
 103 }
 104 
 105 void G1BarrierSet::invalidate(MemRegion mr) {
 106   if (mr.is_empty()) {
 107     return;
 108   }
 109   volatile CardValue* byte = _card_table->byte_for(mr.start());
 110   CardValue* last_byte = _card_table->byte_for(mr.last());
 111   // skip initial young cards
 112   for (; byte <= last_byte && *byte == G1CardTable::g1_young_card_val(); byte++);
 113 
 114   if (byte <= last_byte) {
 115     OrderAccess::storeload();
 116     // Enqueue if necessary.
 117     Thread* thr = Thread::current();
 118     G1DirtyCardQueue& queue = G1ThreadLocalData::dirty_card_queue(thr);
 119     for (; byte <= last_byte; byte++) {
 120       CardValue bv = *byte;
 121       if ((bv != G1CardTable::g1_young_card_val()) &&
 122           (bv != G1CardTable::dirty_card_val())) {
 123         *byte = G1CardTable::dirty_card_val();
 124         queue.enqueue(byte);
 125       }
 126     }
 127   }
 128 }
 129 
 130 void G1BarrierSet::on_thread_create(Thread* thread) {
 131   // Create thread local data
 132   G1ThreadLocalData::create(thread);
 133 }
 134 
 135 void G1BarrierSet::on_thread_destroy(Thread* thread) {
 136   // Destroy thread local data
 137   G1ThreadLocalData::destroy(thread);
 138 }
 139 
 140 void G1BarrierSet::on_thread_attach(Thread* thread) {
 141   assert(!G1ThreadLocalData::satb_mark_queue(thread).is_active(), "SATB queue should not be active");
 142   assert(G1ThreadLocalData::satb_mark_queue(thread).is_empty(), "SATB queue should be empty");
 143   assert(G1ThreadLocalData::dirty_card_queue(thread).is_active(), "Dirty card queue should be active");
 144   // Can't assert that the DCQ is empty.  There is early execution on
 145   // the main thread, before it gets added to the threads list, which
 146   // is where this is called.  That execution may enqueue dirty cards.
 147 
 148   // If we are creating the thread during a marking cycle, we should
 149   // set the active field of the SATB queue to true.  That involves
 150   // copying the global is_active value to this thread's queue, which
 151   // is done without any direct synchronization here.
 152   //
 153   // The activation and deactivation of the SATB queues occurs at the
 154   // beginning / end of a marking cycle, and is done during
 155   // safepoints.  This function is called just before a thread is
 156   // added to its corresponding threads list (for Java or non-Java
 157   // threads, respectively).
 158   //
 159   // For Java threads, that's done while holding the Threads_lock,
 160   // which ensures we're not at a safepoint, so reading the global
 161   // is_active state is synchronized against update.
 162   assert(!thread->is_Java_thread() || !SafepointSynchronize::is_at_safepoint(),
 163          "Should not be at a safepoint");
 164   // For non-Java threads, thread creation (and list addition) may,
 165   // and indeed usually does, occur during a safepoint.  But such
 166   // creation isn't concurrent with updating the global SATB active
 167   // state.
 168   bool is_satb_active = _satb_mark_queue_set.is_active();
 169   G1ThreadLocalData::satb_mark_queue(thread).set_active(is_satb_active);
 170 }
 171 
 172 void G1BarrierSet::on_thread_detach(Thread* thread) {
 173   // Flush any deferred card marks.
 174   CardTableBarrierSet::on_thread_detach(thread);
 175   G1ThreadLocalData::satb_mark_queue(thread).flush();
 176   G1ThreadLocalData::dirty_card_queue(thread).flush();
 177 }
 178 
 179 BufferNode::Allocator& G1BarrierSet::satb_mark_queue_buffer_allocator() {
 180   return _satb_mark_queue_buffer_allocator;
 181 }
 182 
 183 BufferNode::Allocator& G1BarrierSet::dirty_card_queue_buffer_allocator() {
 184   return _dirty_card_queue_buffer_allocator;
 185 }