1 /* 2 * Copyright (c) 2013, 2020, Red Hat, Inc. 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/shenandoah/shenandoahAsserts.hpp" 27 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 28 #include "gc/shenandoah/shenandoahBarrierSetClone.inline.hpp" 29 #include "gc/shenandoah/shenandoahBarrierSetAssembler.hpp" 30 #include "gc/shenandoah/shenandoahBarrierSetNMethod.hpp" 31 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 32 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp" 33 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 34 #include "gc/shenandoah/shenandoahHeuristics.hpp" 35 #include "gc/shenandoah/shenandoahTraversalGC.hpp" 36 #include "memory/iterator.inline.hpp" 37 #include "runtime/interfaceSupport.inline.hpp" 38 #ifdef COMPILER1 39 #include "gc/shenandoah/c1/shenandoahBarrierSetC1.hpp" 40 #endif 41 #ifdef COMPILER2 42 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp" 43 #endif 44 45 class ShenandoahBarrierSetC1; 46 class ShenandoahBarrierSetC2; 47 48 static BarrierSetNMethod* make_barrier_set_nmethod(ShenandoahHeap* heap) { 49 // NMethod barriers are only used when concurrent nmethod unloading is enabled 50 if (!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) { 51 return NULL; 52 } 53 return new ShenandoahBarrierSetNMethod(heap); 54 } 55 56 ShenandoahBarrierSet::ShenandoahBarrierSet(ShenandoahHeap* heap) : 57 BarrierSet(make_barrier_set_assembler<ShenandoahBarrierSetAssembler>(), 58 make_barrier_set_c1<ShenandoahBarrierSetC1>(), 59 make_barrier_set_c2<ShenandoahBarrierSetC2>(), 60 make_barrier_set_nmethod(heap), 61 BarrierSet::FakeRtti(BarrierSet::ShenandoahBarrierSet)), 62 _heap(heap), 63 _satb_mark_queue_buffer_allocator("SATB Buffer Allocator", ShenandoahSATBBufferSize), 64 _satb_mark_queue_set(&_satb_mark_queue_buffer_allocator) 65 { 66 } 67 68 ShenandoahBarrierSetAssembler* ShenandoahBarrierSet::assembler() { 69 BarrierSetAssembler* const bsa = BarrierSet::barrier_set()->barrier_set_assembler(); 70 return reinterpret_cast<ShenandoahBarrierSetAssembler*>(bsa); 71 } 72 73 void ShenandoahBarrierSet::print_on(outputStream* st) const { 74 st->print("ShenandoahBarrierSet"); 75 } 76 77 bool ShenandoahBarrierSet::is_a(BarrierSet::Name bsn) { 78 return bsn == BarrierSet::ShenandoahBarrierSet; 79 } 80 81 bool ShenandoahBarrierSet::is_aligned(HeapWord* hw) { 82 return true; 83 } 84 85 bool ShenandoahBarrierSet::need_load_reference_barrier(DecoratorSet decorators, BasicType type) { 86 if (!ShenandoahLoadRefBarrier) return false; 87 // Only needed for references 88 return is_reference_type(type); 89 } 90 91 bool ShenandoahBarrierSet::use_load_reference_barrier_native(DecoratorSet decorators, BasicType type) { 92 assert(need_load_reference_barrier(decorators, type), "Should be subset of LRB"); 93 assert(is_reference_type(type), "Why we here?"); 94 // Native load reference barrier is only needed for concurrent root processing 95 if (!ShenandoahConcurrentRoots::can_do_concurrent_roots()) { 96 return false; 97 } 98 99 return (decorators & IN_NATIVE) != 0; 100 } 101 102 bool ShenandoahBarrierSet::need_keep_alive_barrier(DecoratorSet decorators,BasicType type) { 103 if (!ShenandoahKeepAliveBarrier) return false; 104 // Only needed for references 105 if (!is_reference_type(type)) return false; 106 107 bool keep_alive = (decorators & AS_NO_KEEPALIVE) == 0; 108 bool unknown = (decorators & ON_UNKNOWN_OOP_REF) != 0; 109 bool is_traversal_mode = ShenandoahHeap::heap()->is_traversal_mode(); 110 bool on_weak_ref = (decorators & (ON_WEAK_OOP_REF | ON_PHANTOM_OOP_REF)) != 0; 111 return (on_weak_ref || unknown) && (keep_alive || is_traversal_mode); 112 } 113 114 oop ShenandoahBarrierSet::load_reference_barrier_not_null(oop obj) { 115 if (ShenandoahLoadRefBarrier && _heap->has_forwarded_objects()) { 116 return load_reference_barrier_impl(obj); 117 } else { 118 return obj; 119 } 120 } 121 122 oop ShenandoahBarrierSet::load_reference_barrier(oop obj) { 123 if (obj != NULL) { 124 return load_reference_barrier_not_null(obj); 125 } else { 126 return obj; 127 } 128 } 129 130 oop ShenandoahBarrierSet::load_reference_barrier_mutator(oop obj, oop* load_addr) { 131 return load_reference_barrier_mutator_work(obj, load_addr); 132 } 133 134 oop ShenandoahBarrierSet::load_reference_barrier_mutator(oop obj, narrowOop* load_addr) { 135 return load_reference_barrier_mutator_work(obj, load_addr); 136 } 137 138 template <class T> 139 oop ShenandoahBarrierSet::load_reference_barrier_mutator_work(oop obj, T* load_addr) { 140 assert(ShenandoahLoadRefBarrier, "should be enabled"); 141 shenandoah_assert_in_cset(load_addr, obj); 142 143 oop fwd = resolve_forwarded_not_null_mutator(obj); 144 if (obj == fwd) { 145 assert(_heap->is_gc_in_progress_mask(ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL), 146 "evac should be in progress"); 147 148 ShenandoahEvacOOMScope oom_evac_scope; 149 150 Thread* thread = Thread::current(); 151 oop res_oop = _heap->evacuate_object(obj, thread); 152 153 // Since we are already here and paid the price of getting through runtime call adapters 154 // and acquiring oom-scope, it makes sense to try and evacuate more adjacent objects, 155 // thus amortizing the overhead. For sparsely live heaps, scan costs easily dominate 156 // total assist costs, and can introduce a lot of evacuation latency. This is why we 157 // only scan for _nearest_ N objects, regardless if they are eligible for evac or not. 158 // The scan itself should also avoid touching the non-marked objects below TAMS, because 159 // their metadata (notably, klasses) may be incorrect already. 160 161 size_t max = ShenandoahEvacAssist; 162 if (max > 0) { 163 // Traversal is special: it uses incomplete marking context, because it coalesces evac with mark. 164 // Other code uses complete marking context, because evac happens after the mark. 165 ShenandoahMarkingContext* ctx = _heap->is_concurrent_traversal_in_progress() ? 166 _heap->marking_context() : _heap->complete_marking_context(); 167 168 ShenandoahHeapRegion* r = _heap->heap_region_containing(obj); 169 assert(r->is_cset(), "sanity"); 170 171 HeapWord* cur = cast_from_oop<HeapWord*>(obj) + obj->size(); 172 173 size_t count = 0; 174 while ((cur < r->top()) && ctx->is_marked(oop(cur)) && (count++ < max)) { 175 oop cur_oop = oop(cur); 176 if (cur_oop == resolve_forwarded_not_null_mutator(cur_oop)) { 177 _heap->evacuate_object(cur_oop, thread); 178 } 179 cur = cur + cur_oop->size(); 180 } 181 } 182 183 fwd = res_oop; 184 } 185 186 if (load_addr != NULL && fwd != obj) { 187 // Since we are here and we know the load address, update the reference. 188 ShenandoahHeap::cas_oop(fwd, load_addr, obj); 189 } 190 191 return fwd; 192 } 193 194 oop ShenandoahBarrierSet::load_reference_barrier_impl(oop obj) { 195 assert(ShenandoahLoadRefBarrier, "should be enabled"); 196 if (!CompressedOops::is_null(obj)) { 197 bool evac_in_progress = _heap->is_gc_in_progress_mask(ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL); 198 oop fwd = resolve_forwarded_not_null(obj); 199 if (evac_in_progress && 200 _heap->in_collection_set(obj) && 201 obj == fwd) { 202 Thread *t = Thread::current(); 203 ShenandoahEvacOOMScope oom_evac_scope; 204 return _heap->evacuate_object(obj, t); 205 } else { 206 return fwd; 207 } 208 } else { 209 return obj; 210 } 211 } 212 213 void ShenandoahBarrierSet::on_thread_create(Thread* thread) { 214 // Create thread local data 215 ShenandoahThreadLocalData::create(thread); 216 } 217 218 void ShenandoahBarrierSet::on_thread_destroy(Thread* thread) { 219 // Destroy thread local data 220 ShenandoahThreadLocalData::destroy(thread); 221 } 222 223 void ShenandoahBarrierSet::on_thread_attach(Thread *thread) { 224 assert(!thread->is_Java_thread() || !SafepointSynchronize::is_at_safepoint(), 225 "We should not be at a safepoint"); 226 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread); 227 assert(!queue.is_active(), "SATB queue should not be active"); 228 assert( queue.is_empty(), "SATB queue should be empty"); 229 queue.set_active(_satb_mark_queue_set.is_active()); 230 if (thread->is_Java_thread()) { 231 ShenandoahThreadLocalData::set_gc_state(thread, _heap->gc_state()); 232 ShenandoahThreadLocalData::initialize_gclab(thread); 233 } 234 } 235 236 void ShenandoahBarrierSet::on_thread_detach(Thread *thread) { 237 SATBMarkQueue& queue = ShenandoahThreadLocalData::satb_mark_queue(thread); 238 queue.flush(); 239 if (thread->is_Java_thread()) { 240 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 241 if (gclab != NULL) { 242 gclab->retire(); 243 } 244 } 245 } 246 247 oop ShenandoahBarrierSet::load_reference_barrier_native(oop obj, oop* load_addr) { 248 return load_reference_barrier_native_impl(obj, load_addr); 249 } 250 251 oop ShenandoahBarrierSet::load_reference_barrier_native(oop obj, narrowOop* load_addr) { 252 return load_reference_barrier_native_impl(obj, load_addr); 253 } 254 255 template <class T> 256 oop ShenandoahBarrierSet::load_reference_barrier_native_impl(oop obj, T* load_addr) { 257 if (CompressedOops::is_null(obj)) { 258 return NULL; 259 } 260 261 ShenandoahMarkingContext* const marking_context = _heap->marking_context(); 262 if (_heap->is_concurrent_root_in_progress() && !marking_context->is_marked(obj)) { 263 Thread* thr = Thread::current(); 264 if (thr->is_Java_thread()) { 265 return NULL; 266 } else { 267 return obj; 268 } 269 } 270 271 oop fwd = load_reference_barrier_not_null(obj); 272 if (load_addr != NULL && fwd != obj) { 273 // Since we are here and we know the load address, update the reference. 274 ShenandoahHeap::cas_oop(fwd, load_addr, obj); 275 } 276 277 return fwd; 278 } 279 280 void ShenandoahBarrierSet::clone_barrier_runtime(oop src) { 281 if (_heap->has_forwarded_objects()) { 282 clone_barrier(src); 283 } 284 } 285