1 /*
   2  * Copyright (c) 2001, 2007, 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 "incls/_precompiled.incl"
  26 # include "incls/_satbQueue.cpp.incl"
  27 
  28 void ObjPtrQueue::apply_closure(ObjectClosure* cl) {
  29   if (_buf != NULL) {
  30     apply_closure_to_buffer(cl, _buf, _index, _sz);
  31     _index = _sz;
  32   }
  33 }
  34 
  35 void ObjPtrQueue::apply_closure_to_buffer(ObjectClosure* cl,
  36                                           void** buf, size_t index, size_t sz) {
  37   if (cl == NULL) return;
  38   for (size_t i = index; i < sz; i += oopSize) {
  39     oop obj = (oop)buf[byte_index_to_index((int)i)];
  40     // There can be NULL entries because of destructors.
  41     if (obj != NULL) {
  42       cl->do_object(obj);
  43     }
  44   }
  45 }
  46 
  47 #ifdef ASSERT
  48 void ObjPtrQueue::verify_oops_in_buffer() {
  49   if (_buf == NULL) return;
  50   for (size_t i = _index; i < _sz; i += oopSize) {
  51     oop obj = (oop)_buf[byte_index_to_index((int)i)];
  52     assert(obj != NULL && obj->is_oop(true /* ignore mark word */),
  53            "Not an oop");
  54   }
  55 }
  56 #endif
  57 
  58 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
  59 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
  60 #endif // _MSC_VER
  61 
  62 
  63 SATBMarkQueueSet::SATBMarkQueueSet() :
  64   PtrQueueSet(),
  65   _closure(NULL), _par_closures(NULL),
  66   _shared_satb_queue(this, true /*perm*/)
  67 {}
  68 
  69 void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
  70                                   int process_completed_threshold,
  71                                   Mutex* lock) {
  72   PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold, -1);
  73   _shared_satb_queue.set_lock(lock);
  74   if (ParallelGCThreads > 0) {
  75     _par_closures = NEW_C_HEAP_ARRAY(ObjectClosure*, ParallelGCThreads);
  76   }
  77 }
  78 
  79 
  80 void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) {
  81   DEBUG_ONLY(t->satb_mark_queue().verify_oops_in_buffer();)
  82   t->satb_mark_queue().handle_zero_index();
  83 }
  84 
  85 #ifdef ASSERT
  86 void SATBMarkQueueSet::dump_active_values(JavaThread* first,
  87                                           bool expected_active) {
  88   gclog_or_tty->print_cr("SATB queue active values for Java Threads");
  89   gclog_or_tty->print_cr(" SATB queue set: active is %s",
  90                          (is_active()) ? "TRUE" : "FALSE");
  91   gclog_or_tty->print_cr(" expected_active is %s",
  92                          (expected_active) ? "TRUE" : "FALSE");
  93   for (JavaThread* t = first; t; t = t->next()) {
  94     bool active = t->satb_mark_queue().is_active();
  95     gclog_or_tty->print_cr("  thread %s, active is %s",
  96                            t->name(), (active) ? "TRUE" : "FALSE");
  97   }
  98 }
  99 #endif // ASSERT
 100 
 101 void SATBMarkQueueSet::set_active_all_threads(bool b,
 102                                               bool expected_active) {
 103   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 104   JavaThread* first = Threads::first();
 105 
 106 #ifdef ASSERT
 107   if (_all_active != expected_active) {
 108     dump_active_values(first, expected_active);
 109 
 110     // I leave this here as a guarantee, instead of an assert, so
 111     // that it will still be compiled in if we choose to uncomment
 112     // the #ifdef ASSERT in a product build. The whole block is
 113     // within an #ifdef ASSERT so the guarantee will not be compiled
 114     // in a product build anyway.
 115     guarantee(false,
 116               "SATB queue set has an unexpected active value");
 117   }
 118 #endif // ASSERT
 119   _all_active = b;
 120 
 121   for (JavaThread* t = first; t; t = t->next()) {
 122 #ifdef ASSERT
 123     bool active = t->satb_mark_queue().is_active();
 124     if (active != expected_active) {
 125       dump_active_values(first, expected_active);
 126 
 127       // I leave this here as a guarantee, instead of an assert, so
 128       // that it will still be compiled in if we choose to uncomment
 129       // the #ifdef ASSERT in a product build. The whole block is
 130       // within an #ifdef ASSERT so the guarantee will not be compiled
 131       // in a product build anyway.
 132       guarantee(false,
 133                 "thread has an unexpected active value in its SATB queue");
 134     }
 135 #endif // ASSERT
 136     t->satb_mark_queue().set_active(b);
 137   }
 138 }
 139 
 140 void SATBMarkQueueSet::set_closure(ObjectClosure* closure) {
 141   _closure = closure;
 142 }
 143 
 144 void SATBMarkQueueSet::set_par_closure(int i, ObjectClosure* par_closure) {
 145   assert(ParallelGCThreads > 0 && _par_closures != NULL, "Precondition");
 146   _par_closures[i] = par_closure;
 147 }
 148 
 149 void SATBMarkQueueSet::iterate_closure_all_threads() {
 150   for(JavaThread* t = Threads::first(); t; t = t->next()) {
 151     t->satb_mark_queue().apply_closure(_closure);
 152   }
 153   shared_satb_queue()->apply_closure(_closure);
 154 }
 155 
 156 void SATBMarkQueueSet::par_iterate_closure_all_threads(int worker) {
 157   SharedHeap* sh = SharedHeap::heap();
 158   int parity = sh->strong_roots_parity();
 159 
 160   for(JavaThread* t = Threads::first(); t; t = t->next()) {
 161     if (t->claim_oops_do(true, parity)) {
 162       t->satb_mark_queue().apply_closure(_par_closures[worker]);
 163     }
 164   }
 165   // We'll have worker 0 do this one.
 166   if (worker == 0) {
 167     shared_satb_queue()->apply_closure(_par_closures[0]);
 168   }
 169 }
 170 
 171 bool SATBMarkQueueSet::apply_closure_to_completed_buffer_work(bool par,
 172                                                               int worker) {
 173   BufferNode* nd = NULL;
 174   {
 175     MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
 176     if (_completed_buffers_head != NULL) {
 177       nd = _completed_buffers_head;
 178       _completed_buffers_head = nd->next();
 179       if (_completed_buffers_head == NULL) _completed_buffers_tail = NULL;
 180       _n_completed_buffers--;
 181       if (_n_completed_buffers == 0) _process_completed = false;
 182     }
 183   }
 184   ObjectClosure* cl = (par ? _par_closures[worker] : _closure);
 185   if (nd != NULL) {
 186     void **buf = BufferNode::make_buffer_from_node(nd);
 187     ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz);
 188     deallocate_buffer(buf);
 189     return true;
 190   } else {
 191     return false;
 192   }
 193 }
 194 
 195 void SATBMarkQueueSet::abandon_partial_marking() {
 196   BufferNode* buffers_to_delete = NULL;
 197   {
 198     MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
 199     while (_completed_buffers_head != NULL) {
 200       BufferNode* nd = _completed_buffers_head;
 201       _completed_buffers_head = nd->next();
 202       nd->set_next(buffers_to_delete);
 203       buffers_to_delete = nd;
 204     }
 205     _completed_buffers_tail = NULL;
 206     _n_completed_buffers = 0;
 207     DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked());
 208   }
 209   while (buffers_to_delete != NULL) {
 210     BufferNode* nd = buffers_to_delete;
 211     buffers_to_delete = nd->next();
 212     deallocate_buffer(BufferNode::make_buffer_from_node(nd));
 213   }
 214   assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
 215   // So we can safely manipulate these queues.
 216   for (JavaThread* t = Threads::first(); t; t = t->next()) {
 217     t->satb_mark_queue().reset();
 218   }
 219   shared_satb_queue()->reset();
 220 }