Fri, 18 Feb 2011 10:07:34 -0800
7020042: G1: Partially remove fix for 6994628
Summary: Disable reference discovery and processing during concurrent marking by disabling fix for 6994628.
Reviewed-by: tonyp, ysr
ysr@777 | 1 | /* |
tonyp@2469 | 2 | * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
ysr@777 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
ysr@777 | 4 | * |
ysr@777 | 5 | * This code is free software; you can redistribute it and/or modify it |
ysr@777 | 6 | * under the terms of the GNU General Public License version 2 only, as |
ysr@777 | 7 | * published by the Free Software Foundation. |
ysr@777 | 8 | * |
ysr@777 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
ysr@777 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
ysr@777 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
ysr@777 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
ysr@777 | 13 | * accompanied this code). |
ysr@777 | 14 | * |
ysr@777 | 15 | * You should have received a copy of the GNU General Public License version |
ysr@777 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
ysr@777 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
ysr@777 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
ysr@777 | 22 | * |
ysr@777 | 23 | */ |
ysr@777 | 24 | |
stefank@2314 | 25 | #include "precompiled.hpp" |
tonyp@2469 | 26 | #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" |
stefank@2314 | 27 | #include "gc_implementation/g1/satbQueue.hpp" |
stefank@2314 | 28 | #include "memory/allocation.inline.hpp" |
stefank@2314 | 29 | #include "memory/sharedHeap.hpp" |
stefank@2314 | 30 | #include "runtime/mutexLocker.hpp" |
stefank@2314 | 31 | #include "runtime/thread.hpp" |
ysr@777 | 32 | |
tonyp@2469 | 33 | // This method removes entries from an SATB buffer that will not be |
tonyp@2469 | 34 | // useful to the concurrent marking threads. An entry is removed if it |
tonyp@2469 | 35 | // satisfies one of the following conditions: |
tonyp@2469 | 36 | // |
tonyp@2469 | 37 | // * it points to an object outside the G1 heap (G1's concurrent |
tonyp@2469 | 38 | // marking only visits objects inside the G1 heap), |
tonyp@2469 | 39 | // * it points to an object that has been allocated since marking |
tonyp@2469 | 40 | // started (according to SATB those objects do not need to be |
tonyp@2469 | 41 | // visited during marking), or |
tonyp@2469 | 42 | // * it points to an object that has already been marked (no need to |
tonyp@2469 | 43 | // process it again). |
tonyp@2469 | 44 | // |
tonyp@2469 | 45 | // The rest of the entries will be retained and are compacted towards |
tonyp@2469 | 46 | // the top of the buffer. If with this filtering we clear a large |
tonyp@2469 | 47 | // enough chunk of the buffer we can re-use it (instead of enqueueing |
tonyp@2469 | 48 | // it) and we can just allow the mutator to carry on executing. |
tonyp@2469 | 49 | |
tonyp@2469 | 50 | bool ObjPtrQueue::should_enqueue_buffer() { |
tonyp@2469 | 51 | assert(_lock == NULL || _lock->owned_by_self(), |
tonyp@2469 | 52 | "we should have taken the lock before calling this"); |
tonyp@2469 | 53 | |
tonyp@2469 | 54 | // A value of 0 means "don't filter SATB buffers". |
tonyp@2469 | 55 | if (G1SATBBufferEnqueueingThresholdPercent == 0) { |
tonyp@2469 | 56 | return true; |
tonyp@2469 | 57 | } |
tonyp@2469 | 58 | |
tonyp@2469 | 59 | G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
tonyp@2469 | 60 | |
tonyp@2469 | 61 | // This method should only be called if there is a non-NULL buffer |
tonyp@2469 | 62 | // that is full. |
tonyp@2469 | 63 | assert(_index == 0, "pre-condition"); |
tonyp@2469 | 64 | assert(_buf != NULL, "pre-condition"); |
tonyp@2469 | 65 | |
tonyp@2469 | 66 | void** buf = _buf; |
tonyp@2469 | 67 | size_t sz = _sz; |
tonyp@2469 | 68 | |
tonyp@2469 | 69 | // Used for sanity checking at the end of the loop. |
tonyp@2469 | 70 | debug_only(size_t entries = 0; size_t retained = 0;) |
tonyp@2469 | 71 | |
tonyp@2469 | 72 | size_t i = sz; |
tonyp@2469 | 73 | size_t new_index = sz; |
tonyp@2469 | 74 | |
tonyp@2469 | 75 | // Given that we are expecting _index == 0, we could have changed |
tonyp@2469 | 76 | // the loop condition to (i > 0). But we are using _index for |
tonyp@2469 | 77 | // generality. |
tonyp@2469 | 78 | while (i > _index) { |
tonyp@2469 | 79 | assert(i > 0, "we should have at least one more entry to process"); |
tonyp@2469 | 80 | i -= oopSize; |
tonyp@2469 | 81 | debug_only(entries += 1;) |
tonyp@2469 | 82 | oop* p = (oop*) &buf[byte_index_to_index((int) i)]; |
tonyp@2469 | 83 | oop obj = *p; |
tonyp@2469 | 84 | // NULL the entry so that unused parts of the buffer contain NULLs |
tonyp@2469 | 85 | // at the end. If we are going to retain it we will copy it to its |
tonyp@2469 | 86 | // final place. If we have retained all entries we have visited so |
tonyp@2469 | 87 | // far, we'll just end up copying it to the same place. |
tonyp@2469 | 88 | *p = NULL; |
tonyp@2469 | 89 | |
tonyp@2469 | 90 | bool retain = g1h->is_obj_ill(obj); |
tonyp@2469 | 91 | if (retain) { |
tonyp@2469 | 92 | assert(new_index > 0, "we should not have already filled up the buffer"); |
tonyp@2469 | 93 | new_index -= oopSize; |
tonyp@2469 | 94 | assert(new_index >= i, |
tonyp@2469 | 95 | "new_index should never be below i, as we alwaysr compact 'up'"); |
tonyp@2469 | 96 | oop* new_p = (oop*) &buf[byte_index_to_index((int) new_index)]; |
tonyp@2469 | 97 | assert(new_p >= p, "the destination location should never be below " |
tonyp@2469 | 98 | "the source as we always compact 'up'"); |
tonyp@2469 | 99 | assert(*new_p == NULL, |
tonyp@2469 | 100 | "we should have already cleared the destination location"); |
tonyp@2469 | 101 | *new_p = obj; |
tonyp@2469 | 102 | debug_only(retained += 1;) |
tonyp@2469 | 103 | } |
tonyp@2469 | 104 | } |
tonyp@2469 | 105 | size_t entries_calc = (sz - _index) / oopSize; |
tonyp@2469 | 106 | assert(entries == entries_calc, "the number of entries we counted " |
tonyp@2469 | 107 | "should match the number of entries we calculated"); |
tonyp@2469 | 108 | size_t retained_calc = (sz - new_index) / oopSize; |
tonyp@2469 | 109 | assert(retained == retained_calc, "the number of retained entries we counted " |
tonyp@2469 | 110 | "should match the number of retained entries we calculated"); |
tonyp@2469 | 111 | size_t perc = retained_calc * 100 / entries_calc; |
tonyp@2469 | 112 | bool should_enqueue = perc > (size_t) G1SATBBufferEnqueueingThresholdPercent; |
tonyp@2469 | 113 | _index = new_index; |
tonyp@2469 | 114 | |
tonyp@2469 | 115 | return should_enqueue; |
tonyp@2469 | 116 | } |
tonyp@2469 | 117 | |
ysr@777 | 118 | void ObjPtrQueue::apply_closure(ObjectClosure* cl) { |
ysr@777 | 119 | if (_buf != NULL) { |
ysr@777 | 120 | apply_closure_to_buffer(cl, _buf, _index, _sz); |
ysr@777 | 121 | _index = _sz; |
ysr@777 | 122 | } |
ysr@777 | 123 | } |
ysr@777 | 124 | |
ysr@777 | 125 | void ObjPtrQueue::apply_closure_to_buffer(ObjectClosure* cl, |
ysr@777 | 126 | void** buf, size_t index, size_t sz) { |
ysr@777 | 127 | if (cl == NULL) return; |
ysr@777 | 128 | for (size_t i = index; i < sz; i += oopSize) { |
ysr@777 | 129 | oop obj = (oop)buf[byte_index_to_index((int)i)]; |
ysr@777 | 130 | // There can be NULL entries because of destructors. |
ysr@777 | 131 | if (obj != NULL) { |
ysr@777 | 132 | cl->do_object(obj); |
ysr@777 | 133 | } |
ysr@777 | 134 | } |
ysr@777 | 135 | } |
ysr@1280 | 136 | |
ysr@1280 | 137 | #ifdef ASSERT |
ysr@1280 | 138 | void ObjPtrQueue::verify_oops_in_buffer() { |
ysr@1280 | 139 | if (_buf == NULL) return; |
ysr@1280 | 140 | for (size_t i = _index; i < _sz; i += oopSize) { |
ysr@1280 | 141 | oop obj = (oop)_buf[byte_index_to_index((int)i)]; |
ysr@1280 | 142 | assert(obj != NULL && obj->is_oop(true /* ignore mark word */), |
ysr@1280 | 143 | "Not an oop"); |
ysr@1280 | 144 | } |
ysr@1280 | 145 | } |
ysr@1280 | 146 | #endif |
ysr@1280 | 147 | |
ysr@777 | 148 | #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away |
ysr@777 | 149 | #pragma warning( disable:4355 ) // 'this' : used in base member initializer list |
ysr@777 | 150 | #endif // _MSC_VER |
ysr@777 | 151 | |
ysr@777 | 152 | |
ysr@777 | 153 | SATBMarkQueueSet::SATBMarkQueueSet() : |
ysr@777 | 154 | PtrQueueSet(), |
ysr@777 | 155 | _closure(NULL), _par_closures(NULL), |
ysr@777 | 156 | _shared_satb_queue(this, true /*perm*/) |
ysr@777 | 157 | {} |
ysr@777 | 158 | |
ysr@777 | 159 | void SATBMarkQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock, |
iveresov@1546 | 160 | int process_completed_threshold, |
ysr@777 | 161 | Mutex* lock) { |
iveresov@1546 | 162 | PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold, -1); |
ysr@777 | 163 | _shared_satb_queue.set_lock(lock); |
ysr@777 | 164 | if (ParallelGCThreads > 0) { |
ysr@777 | 165 | _par_closures = NEW_C_HEAP_ARRAY(ObjectClosure*, ParallelGCThreads); |
ysr@777 | 166 | } |
ysr@777 | 167 | } |
ysr@777 | 168 | |
ysr@777 | 169 | |
ysr@777 | 170 | void SATBMarkQueueSet::handle_zero_index_for_thread(JavaThread* t) { |
ysr@1280 | 171 | DEBUG_ONLY(t->satb_mark_queue().verify_oops_in_buffer();) |
ysr@777 | 172 | t->satb_mark_queue().handle_zero_index(); |
ysr@777 | 173 | } |
ysr@777 | 174 | |
tonyp@1752 | 175 | #ifdef ASSERT |
tonyp@1752 | 176 | void SATBMarkQueueSet::dump_active_values(JavaThread* first, |
tonyp@1752 | 177 | bool expected_active) { |
tonyp@1752 | 178 | gclog_or_tty->print_cr("SATB queue active values for Java Threads"); |
tonyp@1752 | 179 | gclog_or_tty->print_cr(" SATB queue set: active is %s", |
tonyp@1752 | 180 | (is_active()) ? "TRUE" : "FALSE"); |
tonyp@1752 | 181 | gclog_or_tty->print_cr(" expected_active is %s", |
tonyp@1752 | 182 | (expected_active) ? "TRUE" : "FALSE"); |
tonyp@1752 | 183 | for (JavaThread* t = first; t; t = t->next()) { |
tonyp@1752 | 184 | bool active = t->satb_mark_queue().is_active(); |
tonyp@1752 | 185 | gclog_or_tty->print_cr(" thread %s, active is %s", |
tonyp@1752 | 186 | t->name(), (active) ? "TRUE" : "FALSE"); |
tonyp@1752 | 187 | } |
tonyp@1752 | 188 | } |
tonyp@1752 | 189 | #endif // ASSERT |
tonyp@1752 | 190 | |
tonyp@1752 | 191 | void SATBMarkQueueSet::set_active_all_threads(bool b, |
tonyp@1752 | 192 | bool expected_active) { |
tonyp@1752 | 193 | assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); |
tonyp@1752 | 194 | JavaThread* first = Threads::first(); |
tonyp@1752 | 195 | |
tonyp@1752 | 196 | #ifdef ASSERT |
tonyp@1752 | 197 | if (_all_active != expected_active) { |
tonyp@1752 | 198 | dump_active_values(first, expected_active); |
tonyp@1752 | 199 | |
tonyp@1752 | 200 | // I leave this here as a guarantee, instead of an assert, so |
tonyp@1752 | 201 | // that it will still be compiled in if we choose to uncomment |
tonyp@1752 | 202 | // the #ifdef ASSERT in a product build. The whole block is |
tonyp@1752 | 203 | // within an #ifdef ASSERT so the guarantee will not be compiled |
tonyp@1752 | 204 | // in a product build anyway. |
tonyp@1752 | 205 | guarantee(false, |
tonyp@1752 | 206 | "SATB queue set has an unexpected active value"); |
tonyp@1752 | 207 | } |
tonyp@1752 | 208 | #endif // ASSERT |
ysr@777 | 209 | _all_active = b; |
tonyp@1752 | 210 | |
tonyp@1752 | 211 | for (JavaThread* t = first; t; t = t->next()) { |
tonyp@1752 | 212 | #ifdef ASSERT |
tonyp@1752 | 213 | bool active = t->satb_mark_queue().is_active(); |
tonyp@1752 | 214 | if (active != expected_active) { |
tonyp@1752 | 215 | dump_active_values(first, expected_active); |
tonyp@1752 | 216 | |
tonyp@1752 | 217 | // I leave this here as a guarantee, instead of an assert, so |
tonyp@1752 | 218 | // that it will still be compiled in if we choose to uncomment |
tonyp@1752 | 219 | // the #ifdef ASSERT in a product build. The whole block is |
tonyp@1752 | 220 | // within an #ifdef ASSERT so the guarantee will not be compiled |
tonyp@1752 | 221 | // in a product build anyway. |
tonyp@1752 | 222 | guarantee(false, |
tonyp@1752 | 223 | "thread has an unexpected active value in its SATB queue"); |
tonyp@1752 | 224 | } |
tonyp@1752 | 225 | #endif // ASSERT |
ysr@777 | 226 | t->satb_mark_queue().set_active(b); |
ysr@777 | 227 | } |
ysr@777 | 228 | } |
ysr@777 | 229 | |
ysr@777 | 230 | void SATBMarkQueueSet::set_closure(ObjectClosure* closure) { |
ysr@777 | 231 | _closure = closure; |
ysr@777 | 232 | } |
ysr@777 | 233 | |
ysr@777 | 234 | void SATBMarkQueueSet::set_par_closure(int i, ObjectClosure* par_closure) { |
ysr@777 | 235 | assert(ParallelGCThreads > 0 && _par_closures != NULL, "Precondition"); |
ysr@777 | 236 | _par_closures[i] = par_closure; |
ysr@777 | 237 | } |
ysr@777 | 238 | |
ysr@777 | 239 | void SATBMarkQueueSet::iterate_closure_all_threads() { |
ysr@777 | 240 | for(JavaThread* t = Threads::first(); t; t = t->next()) { |
ysr@777 | 241 | t->satb_mark_queue().apply_closure(_closure); |
ysr@777 | 242 | } |
ysr@777 | 243 | shared_satb_queue()->apply_closure(_closure); |
ysr@777 | 244 | } |
ysr@777 | 245 | |
ysr@777 | 246 | void SATBMarkQueueSet::par_iterate_closure_all_threads(int worker) { |
ysr@777 | 247 | SharedHeap* sh = SharedHeap::heap(); |
ysr@777 | 248 | int parity = sh->strong_roots_parity(); |
ysr@777 | 249 | |
ysr@777 | 250 | for(JavaThread* t = Threads::first(); t; t = t->next()) { |
ysr@777 | 251 | if (t->claim_oops_do(true, parity)) { |
ysr@777 | 252 | t->satb_mark_queue().apply_closure(_par_closures[worker]); |
ysr@777 | 253 | } |
ysr@777 | 254 | } |
ysr@777 | 255 | // We'll have worker 0 do this one. |
ysr@777 | 256 | if (worker == 0) { |
ysr@777 | 257 | shared_satb_queue()->apply_closure(_par_closures[0]); |
ysr@777 | 258 | } |
ysr@777 | 259 | } |
ysr@777 | 260 | |
ysr@777 | 261 | bool SATBMarkQueueSet::apply_closure_to_completed_buffer_work(bool par, |
ysr@777 | 262 | int worker) { |
iveresov@1546 | 263 | BufferNode* nd = NULL; |
ysr@777 | 264 | { |
ysr@777 | 265 | MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); |
ysr@777 | 266 | if (_completed_buffers_head != NULL) { |
ysr@777 | 267 | nd = _completed_buffers_head; |
iveresov@1546 | 268 | _completed_buffers_head = nd->next(); |
ysr@777 | 269 | if (_completed_buffers_head == NULL) _completed_buffers_tail = NULL; |
ysr@777 | 270 | _n_completed_buffers--; |
ysr@777 | 271 | if (_n_completed_buffers == 0) _process_completed = false; |
ysr@777 | 272 | } |
ysr@777 | 273 | } |
ysr@777 | 274 | ObjectClosure* cl = (par ? _par_closures[worker] : _closure); |
ysr@777 | 275 | if (nd != NULL) { |
iveresov@1546 | 276 | void **buf = BufferNode::make_buffer_from_node(nd); |
iveresov@1546 | 277 | ObjPtrQueue::apply_closure_to_buffer(cl, buf, 0, _sz); |
iveresov@1546 | 278 | deallocate_buffer(buf); |
ysr@777 | 279 | return true; |
ysr@777 | 280 | } else { |
ysr@777 | 281 | return false; |
ysr@777 | 282 | } |
ysr@777 | 283 | } |
ysr@777 | 284 | |
ysr@777 | 285 | void SATBMarkQueueSet::abandon_partial_marking() { |
iveresov@1546 | 286 | BufferNode* buffers_to_delete = NULL; |
ysr@777 | 287 | { |
ysr@777 | 288 | MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag); |
ysr@777 | 289 | while (_completed_buffers_head != NULL) { |
iveresov@1546 | 290 | BufferNode* nd = _completed_buffers_head; |
iveresov@1546 | 291 | _completed_buffers_head = nd->next(); |
iveresov@1546 | 292 | nd->set_next(buffers_to_delete); |
ysr@777 | 293 | buffers_to_delete = nd; |
ysr@777 | 294 | } |
ysr@777 | 295 | _completed_buffers_tail = NULL; |
ysr@777 | 296 | _n_completed_buffers = 0; |
ysr@1280 | 297 | DEBUG_ONLY(assert_completed_buffer_list_len_correct_locked()); |
ysr@777 | 298 | } |
ysr@777 | 299 | while (buffers_to_delete != NULL) { |
iveresov@1546 | 300 | BufferNode* nd = buffers_to_delete; |
iveresov@1546 | 301 | buffers_to_delete = nd->next(); |
iveresov@1546 | 302 | deallocate_buffer(BufferNode::make_buffer_from_node(nd)); |
ysr@777 | 303 | } |
ysr@777 | 304 | assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint."); |
ysr@777 | 305 | // So we can safely manipulate these queues. |
ysr@777 | 306 | for (JavaThread* t = Threads::first(); t; t = t->next()) { |
ysr@777 | 307 | t->satb_mark_queue().reset(); |
ysr@777 | 308 | } |
ysr@777 | 309 | shared_satb_queue()->reset(); |
ysr@777 | 310 | } |