1 /* 2 * Copyright (c) 2014, 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/g1CollectedHeap.inline.hpp" 27 #include "gc_implementation/g1/g1OopClosures.inline.hpp" 28 #include "gc_implementation/g1/g1ParScanThreadState.inline.hpp" 29 #include "oops/oop.inline.hpp" 30 #include "oops/oop.pcgc.inline.hpp" 31 #include "runtime/prefetch.inline.hpp" 32 33 G1ParScanThreadState::G1ParScanThreadState(G1CollectedHeap* g1h, uint queue_num, ReferenceProcessor* rp) 34 : _g1h(g1h), 35 _refs(g1h->task_queue(queue_num)), 36 _dcq(&g1h->dirty_card_queue_set()), 37 _ct_bs(g1h->g1_barrier_set()), 38 _g1_rem(g1h->g1_rem_set()), 39 _hash_seed(17), _queue_num(queue_num), 40 _term_attempts(0), 41 _age_table(false), _scanner(g1h, rp), 42 _strong_roots_time(0), _term_time(0) { 43 _scanner.set_par_scan_thread_state(this); 44 // we allocate G1YoungSurvRateNumRegions plus one entries, since 45 // we "sacrifice" entry 0 to keep track of surviving bytes for 46 // non-young regions (where the age is -1) 47 // We also add a few elements at the beginning and at the end in 48 // an attempt to eliminate cache contention 49 uint real_length = 1 + _g1h->g1_policy()->young_cset_region_length(); 50 uint array_length = PADDING_ELEM_NUM + 51 real_length + 52 PADDING_ELEM_NUM; 53 _surviving_young_words_base = NEW_C_HEAP_ARRAY(size_t, array_length, mtGC); 54 if (_surviving_young_words_base == NULL) 55 vm_exit_out_of_memory(array_length * sizeof(size_t), OOM_MALLOC_ERROR, 56 "Not enough space for young surv histo."); 57 _surviving_young_words = _surviving_young_words_base + PADDING_ELEM_NUM; 58 memset(_surviving_young_words, 0, (size_t) real_length * sizeof(size_t)); 59 60 _g1_par_allocator = G1ParGCAllocator::create_allocator(_g1h); 61 62 _start = os::elapsedTime(); 63 } 64 65 G1ParScanThreadState::~G1ParScanThreadState() { 66 _g1_par_allocator->retire_alloc_buffers(); 67 delete _g1_par_allocator; 68 FREE_C_HEAP_ARRAY(size_t, _surviving_young_words_base, mtGC); 69 } 70 71 void 72 G1ParScanThreadState::print_termination_stats_hdr(outputStream* const st) 73 { 74 st->print_raw_cr("GC Termination Stats"); 75 st->print_raw_cr(" elapsed --strong roots-- -------termination-------" 76 " ------waste (KiB)------"); 77 st->print_raw_cr("thr ms ms % ms % attempts" 78 " total alloc undo"); 79 st->print_raw_cr("--- --------- --------- ------ --------- ------ --------" 80 " ------- ------- -------"); 81 } 82 83 void 84 G1ParScanThreadState::print_termination_stats(int i, 85 outputStream* const st) const 86 { 87 const double elapsed_ms = elapsed_time() * 1000.0; 88 const double s_roots_ms = strong_roots_time() * 1000.0; 89 const double term_ms = term_time() * 1000.0; 90 const size_t alloc_buffer_waste = _g1_par_allocator->alloc_buffer_waste(); 91 const size_t undo_waste = _g1_par_allocator->undo_waste(); 92 st->print_cr("%3d %9.2f %9.2f %6.2f " 93 "%9.2f %6.2f " SIZE_FORMAT_W(8) " " 94 SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7) " " SIZE_FORMAT_W(7), 95 i, elapsed_ms, s_roots_ms, s_roots_ms * 100 / elapsed_ms, 96 term_ms, term_ms * 100 / elapsed_ms, term_attempts(), 97 (alloc_buffer_waste + undo_waste) * HeapWordSize / K, 98 alloc_buffer_waste * HeapWordSize / K, 99 undo_waste * HeapWordSize / K); 100 } 101 102 #ifdef ASSERT 103 bool G1ParScanThreadState::verify_ref(narrowOop* ref) const { 104 assert(ref != NULL, "invariant"); 105 assert(UseCompressedOops, "sanity"); 106 assert(!has_partial_array_mask(ref), err_msg("ref=" PTR_FORMAT, p2i(ref))); 107 oop p = oopDesc::load_decode_heap_oop(ref); 108 assert(_g1h->is_in_g1_reserved(p), 109 err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p))); 110 return true; 111 } 112 113 bool G1ParScanThreadState::verify_ref(oop* ref) const { 114 assert(ref != NULL, "invariant"); 115 if (has_partial_array_mask(ref)) { 116 // Must be in the collection set--it's already been copied. 117 oop p = clear_partial_array_mask(ref); 118 assert(_g1h->obj_in_cs(p), 119 err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p))); 120 } else { 121 oop p = oopDesc::load_decode_heap_oop(ref); 122 assert(_g1h->is_in_g1_reserved(p), 123 err_msg("ref=" PTR_FORMAT " p=" PTR_FORMAT, p2i(ref), p2i(p))); 124 } 125 return true; 126 } 127 128 bool G1ParScanThreadState::verify_task(StarTask ref) const { 129 if (ref.is_narrow()) { 130 return verify_ref((narrowOop*) ref); 131 } else { 132 return verify_ref((oop*) ref); 133 } 134 } 135 #endif // ASSERT 136 137 void G1ParScanThreadState::trim_queue() { 138 assert(_evac_failure_cl != NULL, "not set"); 139 140 StarTask ref; 141 do { 142 // Drain the overflow stack first, so other threads can steal. 143 while (_refs->pop_overflow(ref)) { 144 dispatch_reference(ref); 145 } 146 147 while (_refs->pop_local(ref)) { 148 dispatch_reference(ref); 149 } 150 } while (!_refs->is_empty()); 151 } 152 153 oop G1ParScanThreadState::copy_to_survivor_space(oop const old, 154 markOop const old_mark) { 155 size_t word_sz = old->size(); 156 HeapRegion* from_region = _g1h->heap_region_containing_raw(old); 157 // +1 to make the -1 indexes valid... 158 int young_index = from_region->young_index_in_cset()+1; 159 assert( (from_region->is_young() && young_index > 0) || 160 (!from_region->is_young() && young_index == 0), "invariant" ); 161 G1CollectorPolicy* g1p = _g1h->g1_policy(); 162 uint age = old_mark->has_displaced_mark_helper() ? old_mark->displaced_mark_helper()->age() 163 : old_mark->age(); 164 GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age, 165 word_sz); 166 AllocationContext_t context = from_region->allocation_context(); 167 HeapWord* obj_ptr = _g1_par_allocator->allocate(alloc_purpose, word_sz, context); 168 #ifndef PRODUCT 169 // Should this evacuation fail? 170 if (_g1h->evacuation_should_fail()) { 171 if (obj_ptr != NULL) { 172 _g1_par_allocator->undo_allocation(alloc_purpose, obj_ptr, word_sz, context); 173 obj_ptr = NULL; 174 } 175 } 176 #endif // !PRODUCT 177 178 if (obj_ptr == NULL) { 179 // This will either forward-to-self, or detect that someone else has 180 // installed a forwarding pointer. 181 return _g1h->handle_evacuation_failure_par(this, old); 182 } 183 184 oop obj = oop(obj_ptr); 185 186 // We're going to allocate linearly, so might as well prefetch ahead. 187 Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes); 188 189 oop forward_ptr = old->forward_to_atomic(obj); 190 if (forward_ptr == NULL) { 191 Copy::aligned_disjoint_words((HeapWord*) old, obj_ptr, word_sz); 192 193 // alloc_purpose is just a hint to allocate() above, recheck the type of region 194 // we actually allocated from and update alloc_purpose accordingly 195 HeapRegion* to_region = _g1h->heap_region_containing_raw(obj_ptr); 196 alloc_purpose = to_region->is_young() ? GCAllocForSurvived : GCAllocForTenured; 197 198 if (g1p->track_object_age(alloc_purpose)) { 199 if (age < markOopDesc::max_age) { 200 age++; 201 } 202 if (old_mark->has_displaced_mark_helper()) { 203 // In this case, we have to install the mark word first, 204 // otherwise obj looks to be forwarded (the old mark word, 205 // which contains the forward pointer, was copied) 206 obj->set_mark(old_mark); 207 markOop new_mark = old_mark->displaced_mark_helper()->set_age(age); 208 old_mark->set_displaced_mark_helper(new_mark); 209 } else { 210 obj->set_mark(old_mark->set_age(age)); 211 } 212 age_table()->add(age, word_sz); 213 } else { 214 obj->set_mark(old_mark); 215 } 216 217 if (G1StringDedup::is_enabled()) { 218 G1StringDedup::enqueue_from_evacuation(from_region->is_young(), 219 to_region->is_young(), 220 queue_num(), 221 obj); 222 } 223 224 size_t* surv_young_words = surviving_young_words(); 225 surv_young_words[young_index] += word_sz; 226 227 if (obj->is_objArray() && arrayOop(obj)->length() >= ParGCArrayScanChunk) { 228 // We keep track of the next start index in the length field of 229 // the to-space object. The actual length can be found in the 230 // length field of the from-space object. 231 arrayOop(obj)->set_length(0); 232 oop* old_p = set_partial_array_mask(old); 233 push_on_queue(old_p); 234 } else { 235 // No point in using the slower heap_region_containing() method, 236 // given that we know obj is in the heap. 237 _scanner.set_region(_g1h->heap_region_containing_raw(obj)); 238 obj->oop_iterate_backwards(&_scanner); 239 } 240 } else { 241 _g1_par_allocator->undo_allocation(alloc_purpose, obj_ptr, word_sz, context); 242 obj = forward_ptr; 243 } 244 return obj; 245 }