1 /*

     2  * Copyright (c) 2001, 2018, 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/g1CardTable.inline.hpp"

    27 #include "gc/g1/g1CollectedHeap.inline.hpp"

    28 #include "gc/g1/g1SATBCardTableModRefBS.inline.hpp"

    29 #include "gc/g1/heapRegion.hpp"

    30 #include "gc/g1/satbMarkQueue.hpp"

    31 #include "logging/log.hpp"

    32 #include "oops/oop.inline.hpp"

    33 #include "runtime/mutexLocker.hpp"

    34 #include "runtime/thread.inline.hpp"

    35 

    36 G1SATBCardTableModRefBS::G1SATBCardTableModRefBS(

    37   G1CardTable* card_table,

    38   const BarrierSet::FakeRtti& fake_rtti) :

    39   CardTableModRefBS(card_table, fake_rtti.add_tag(BarrierSet::G1SATBCT))

    40 { }

    41 

    42 void G1SATBCardTableModRefBS::enqueue(oop pre_val) {

    43   // Nulls should have been already filtered.

    44   assert(oopDesc::is_oop(pre_val, true), "Error");

    45 

    46   if (!JavaThread::satb_mark_queue_set().is_active()) return;

    47   Thread* thr = Thread::current();

    48   if (thr->is_Java_thread()) {

    49     JavaThread* jt = (JavaThread*)thr;

    50     jt->satb_mark_queue().enqueue(pre_val);

    51   } else {

    52     MutexLockerEx x(Shared_SATB_Q_lock, Mutex::_no_safepoint_check_flag);

    53     JavaThread::satb_mark_queue_set().shared_satb_queue()->enqueue(pre_val);

    54   }

    55 }

    56 

    57 template <class T> void

    58 G1SATBCardTableModRefBS::write_ref_array_pre_work(T* dst, int count) {

    59   if (!JavaThread::satb_mark_queue_set().is_active()) return;

    60   T* elem_ptr = dst;

    61   for (int i = 0; i < count; i++, elem_ptr++) {

    62     T heap_oop = oopDesc::load_heap_oop(elem_ptr);

    63     if (!oopDesc::is_null(heap_oop)) {

    64       enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));

    65     }

    66   }

    67 }

    68 

    69 void G1SATBCardTableModRefBS::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {

    70   if (!dest_uninitialized) {

    71     write_ref_array_pre_work(dst, count);

    72   }

    73 }

    74 

    75 void G1SATBCardTableModRefBS::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {

    76   if (!dest_uninitialized) {

    77     write_ref_array_pre_work(dst, count);

    78   }

    79 }

    80 

    81 G1SATBCardTableLoggingModRefBS::

    82 G1SATBCardTableLoggingModRefBS(G1CardTable* card_table) :

    83   G1SATBCardTableModRefBS(card_table, BarrierSet::FakeRtti(G1SATBCTLogging)),

    84   _dcqs(JavaThread::dirty_card_queue_set()) {}

    85 

    86 void G1SATBCardTableLoggingModRefBS::write_ref_field_post_slow(volatile jbyte* byte) {

    87   // In the slow path, we know a card is not young

    88   assert(*byte != G1CardTable::g1_young_card_val(), "slow path invoked without filtering");

    89   OrderAccess::storeload();

    90   if (*byte != G1CardTable::dirty_card_val()) {

    91     *byte = G1CardTable::dirty_card_val();

    92     Thread* thr = Thread::current();

    93     if (thr->is_Java_thread()) {

    94       JavaThread* jt = (JavaThread*)thr;

    95       jt->dirty_card_queue().enqueue(byte);

    96     } else {

    97       MutexLockerEx x(Shared_DirtyCardQ_lock,

    98                       Mutex::_no_safepoint_check_flag);

    99       _dcqs.shared_dirty_card_queue()->enqueue(byte);

   100     }

   101   }

   102 }

   103 

   104 void G1SATBCardTableLoggingModRefBS::invalidate(MemRegion mr) {

   105   if (mr.is_empty()) {

   106     return;

   107   }

   108   volatile jbyte* byte = _card_table->byte_for(mr.start());

   109   jbyte* last_byte = _card_table->byte_for(mr.last());

   110   Thread* thr = Thread::current();

   111     // skip all consecutive 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     if (thr->is_Java_thread()) {

   118       JavaThread* jt = (JavaThread*)thr;

   119       for (; byte <= last_byte; byte++) {

   120         if (*byte == G1CardTable::g1_young_card_val()) {

   121           continue;

   122         }

   123         if (*byte != G1CardTable::dirty_card_val()) {

   124           *byte = G1CardTable::dirty_card_val();

   125           jt->dirty_card_queue().enqueue(byte);

   126         }

   127       }

   128     } else {

   129       MutexLockerEx x(Shared_DirtyCardQ_lock,

   130                       Mutex::_no_safepoint_check_flag);

   131       for (; byte <= last_byte; byte++) {

   132         if (*byte == G1CardTable::g1_young_card_val()) {

   133           continue;

   134         }

   135         if (*byte != G1CardTable::dirty_card_val()) {

   136           *byte = G1CardTable::dirty_card_val();

   137           _dcqs.shared_dirty_card_queue()->enqueue(byte);

   138         }

   139       }

   140     }

   141   }

   142 }

   143 

   144 void G1SATBCardTableLoggingModRefBS::on_thread_attach(JavaThread* thread) {

   145   // This method initializes the SATB and dirty card queues before a

   146   // JavaThread is added to the Java thread list. Right now, we don't

   147   // have to do anything to the dirty card queue (it should have been

   148   // activated when the thread was created), but we have to activate

   149   // the SATB queue if the thread is created while a marking cycle is

   150   // in progress. The activation / de-activation of the SATB queues at

   151   // the beginning / end of a marking cycle is done during safepoints

   152   // so we have to make sure this method is called outside one to be

   153   // able to safely read the active field of the SATB queue set. Right

   154   // now, it is called just before the thread is added to the Java

   155   // thread list in the Threads::add() method. That method is holding

   156   // the Threads_lock which ensures we are outside a safepoint. We

   157   // cannot do the obvious and set the active field of the SATB queue

   158   // when the thread is created given that, in some cases, safepoints

   159   // might happen between the JavaThread constructor being called and the

   160   // thread being added to the Java thread list (an example of this is

   161   // when the structure for the DestroyJavaVM thread is created).

   162   assert(!SafepointSynchronize::is_at_safepoint(), "We should not be at a safepoint");

   163   assert(!thread->satb_mark_queue().is_active(), "SATB queue should not be active");

   164   assert(thread->satb_mark_queue().is_empty(), "SATB queue should be empty");

   165   assert(thread->dirty_card_queue().is_active(), "Dirty card queue should be active");

   166 

   167   // If we are creating the thread during a marking cycle, we should

   168   // set the active field of the SATB queue to true.

   169   if (thread->satb_mark_queue_set().is_active()) {

   170     thread->satb_mark_queue().set_active(true);

   171   }

   172 }

   173 

   174 void G1SATBCardTableLoggingModRefBS::on_thread_detach(JavaThread* thread) {

   175   // Flush any deferred card marks, SATB buffers and dirty card queue buffers

   176   CardTableModRefBS::on_thread_detach(thread);

   177   thread->satb_mark_queue().flush();

   178   thread->dirty_card_queue().flush();

   179 }