1 /* 2 * Copyright (c) 2017, 2018, Red Hat, Inc. All rights reserved. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "gc/epsilon/epsilonHeap.hpp" 26 #include "gc/epsilon/epsilonMemoryPool.hpp" 27 #include "gc/epsilon/epsilonThreadLocalData.hpp" 28 #include "gc/shared/gcArguments.hpp" 29 #include "gc/shared/locationPrinter.inline.hpp" 30 #include "memory/allocation.hpp" 31 #include "memory/allocation.inline.hpp" 32 #include "memory/resourceArea.hpp" 33 #include "memory/universe.hpp" 34 #include "runtime/atomic.hpp" 35 #include "runtime/globals.hpp" 36 37 jint EpsilonHeap::initialize() { 38 size_t align = HeapAlignment; 39 size_t init_byte_size = align_up(InitialHeapSize, align); 40 size_t max_byte_size = align_up(MaxHeapSize, align); 41 42 // Initialize backing storage 43 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, align); 44 _virtual_space.initialize(heap_rs, init_byte_size); 45 46 MemRegion committed_region((HeapWord*)_virtual_space.low(), (HeapWord*)_virtual_space.high()); 47 MemRegion reserved_region((HeapWord*)_virtual_space.low_boundary(), (HeapWord*)_virtual_space.high_boundary()); 48 49 initialize_reserved_region(heap_rs); 50 51 _space = new ContiguousSpace(); 52 _space->initialize(committed_region, /* clear_space = */ true, /* mangle_space = */ true); 53 54 // Precompute hot fields 55 _max_tlab_size = MIN2(CollectedHeap::max_tlab_size(), align_object_size(EpsilonMaxTLABSize / HeapWordSize)); 56 _step_counter_update = MIN2<size_t>(max_byte_size / 16, EpsilonUpdateCountersStep); 57 _step_heap_print = (EpsilonPrintHeapSteps == 0) ? SIZE_MAX : (max_byte_size / EpsilonPrintHeapSteps); 58 _decay_time_ns = (int64_t) EpsilonTLABDecayTime * NANOSECS_PER_MILLISEC; 59 60 // Enable monitoring 61 _monitoring_support = new EpsilonMonitoringSupport(this); 62 _last_counter_update = 0; 63 _last_heap_print = 0; 64 65 // Install barrier set 66 BarrierSet::set_barrier_set(new EpsilonBarrierSet()); 67 68 // All done, print out the configuration 69 if (init_byte_size != max_byte_size) { 70 log_info(gc)("Resizeable heap; starting at " SIZE_FORMAT "M, max: " SIZE_FORMAT "M, step: " SIZE_FORMAT "M", 71 init_byte_size / M, max_byte_size / M, EpsilonMinHeapExpand / M); 72 } else { 73 log_info(gc)("Non-resizeable heap; start/max: " SIZE_FORMAT "M", init_byte_size / M); 74 } 75 76 if (UseTLAB) { 77 log_info(gc)("Using TLAB allocation; max: " SIZE_FORMAT "K", _max_tlab_size * HeapWordSize / K); 78 if (EpsilonElasticTLAB) { 79 log_info(gc)("Elastic TLABs enabled; elasticity: %.2fx", EpsilonTLABElasticity); 80 } 81 if (EpsilonElasticTLABDecay) { 82 log_info(gc)("Elastic TLABs decay enabled; decay time: " SIZE_FORMAT "ms", EpsilonTLABDecayTime); 83 } 84 } else { 85 log_info(gc)("Not using TLAB allocation"); 86 } 87 88 return JNI_OK; 89 } 90 91 void EpsilonHeap::post_initialize() { 92 CollectedHeap::post_initialize(); 93 } 94 95 void EpsilonHeap::initialize_serviceability() { 96 _pool = new EpsilonMemoryPool(this); 97 _memory_manager.add_pool(_pool); 98 } 99 100 GrowableArray<GCMemoryManager*> EpsilonHeap::memory_managers() { 101 GrowableArray<GCMemoryManager*> memory_managers(1); 102 memory_managers.append(&_memory_manager); 103 return memory_managers; 104 } 105 106 GrowableArray<MemoryPool*> EpsilonHeap::memory_pools() { 107 GrowableArray<MemoryPool*> memory_pools(1); 108 memory_pools.append(_pool); 109 return memory_pools; 110 } 111 112 size_t EpsilonHeap::unsafe_max_tlab_alloc(Thread* thr) const { 113 // Return max allocatable TLAB size, and let allocation path figure out 114 // the actual allocation size. Note: result should be in bytes. 115 return _max_tlab_size * HeapWordSize; 116 } 117 118 EpsilonHeap* EpsilonHeap::heap() { 119 CollectedHeap* heap = Universe::heap(); 120 assert(heap != NULL, "Uninitialized access to EpsilonHeap::heap()"); 121 assert(heap->kind() == CollectedHeap::Epsilon, "Not an Epsilon heap"); 122 return (EpsilonHeap*)heap; 123 } 124 125 HeapWord* EpsilonHeap::allocate_work(size_t size) { 126 assert(is_object_aligned(size), "Allocation size should be aligned: " SIZE_FORMAT, size); 127 128 HeapWord* res = _space->par_allocate(size); 129 130 while (res == NULL) { 131 // Allocation failed, attempt expansion, and retry: 132 MutexLocker ml(Heap_lock); 133 134 size_t space_left = max_capacity() - capacity(); 135 size_t want_space = MAX2(size, EpsilonMinHeapExpand); 136 137 if (want_space < space_left) { 138 // Enough space to expand in bulk: 139 bool expand = _virtual_space.expand_by(want_space); 140 assert(expand, "Should be able to expand"); 141 } else if (size < space_left) { 142 // No space to expand in bulk, and this allocation is still possible, 143 // take all the remaining space: 144 bool expand = _virtual_space.expand_by(space_left); 145 assert(expand, "Should be able to expand"); 146 } else { 147 // No space left: 148 return NULL; 149 } 150 151 _space->set_end((HeapWord *) _virtual_space.high()); 152 res = _space->par_allocate(size); 153 } 154 155 size_t used = _space->used(); 156 157 // Allocation successful, update counters 158 { 159 size_t last = _last_counter_update; 160 if ((used - last >= _step_counter_update) && Atomic::cmpxchg(&_last_counter_update, last, used) == last) { 161 _monitoring_support->update_counters(); 162 } 163 } 164 165 // ...and print the occupancy line, if needed 166 { 167 size_t last = _last_heap_print; 168 if ((used - last >= _step_heap_print) && Atomic::cmpxchg(&_last_heap_print, last, used) == last) { 169 print_heap_info(used); 170 print_metaspace_info(); 171 } 172 } 173 174 assert(is_object_aligned(res), "Object should be aligned: " PTR_FORMAT, p2i(res)); 175 return res; 176 } 177 178 HeapWord* EpsilonHeap::allocate_new_tlab(size_t min_size, 179 size_t requested_size, 180 size_t* actual_size) { 181 Thread* thread = Thread::current(); 182 183 // Defaults in case elastic paths are not taken 184 bool fits = true; 185 size_t size = requested_size; 186 size_t ergo_tlab = requested_size; 187 int64_t time = 0; 188 189 if (EpsilonElasticTLAB) { 190 ergo_tlab = EpsilonThreadLocalData::ergo_tlab_size(thread); 191 192 if (EpsilonElasticTLABDecay) { 193 int64_t last_time = EpsilonThreadLocalData::last_tlab_time(thread); 194 time = (int64_t) os::javaTimeNanos(); 195 196 assert(last_time <= time, "time should be monotonic"); 197 198 // If the thread had not allocated recently, retract the ergonomic size. 199 // This conserves memory when the thread had initial burst of allocations, 200 // and then started allocating only sporadically. 201 if (last_time != 0 && (time - last_time > _decay_time_ns)) { 202 ergo_tlab = 0; 203 EpsilonThreadLocalData::set_ergo_tlab_size(thread, 0); 204 } 205 } 206 207 // If we can fit the allocation under current TLAB size, do so. 208 // Otherwise, we want to elastically increase the TLAB size. 209 fits = (requested_size <= ergo_tlab); 210 if (!fits) { 211 size = (size_t) (ergo_tlab * EpsilonTLABElasticity); 212 } 213 } 214 215 // Always honor boundaries 216 size = clamp(size, min_size, _max_tlab_size); 217 218 // Always honor alignment 219 size = align_up(size, MinObjAlignment); 220 221 // Check that adjustments did not break local and global invariants 222 assert(is_object_aligned(size), 223 "Size honors object alignment: " SIZE_FORMAT, size); 224 assert(min_size <= size, 225 "Size honors min size: " SIZE_FORMAT " <= " SIZE_FORMAT, min_size, size); 226 assert(size <= _max_tlab_size, 227 "Size honors max size: " SIZE_FORMAT " <= " SIZE_FORMAT, size, _max_tlab_size); 228 assert(size <= CollectedHeap::max_tlab_size(), 229 "Size honors global max size: " SIZE_FORMAT " <= " SIZE_FORMAT, size, CollectedHeap::max_tlab_size()); 230 231 if (log_is_enabled(Trace, gc)) { 232 ResourceMark rm; 233 log_trace(gc)("TLAB size for \"%s\" (Requested: " SIZE_FORMAT "K, Min: " SIZE_FORMAT 234 "K, Max: " SIZE_FORMAT "K, Ergo: " SIZE_FORMAT "K) -> " SIZE_FORMAT "K", 235 thread->name(), 236 requested_size * HeapWordSize / K, 237 min_size * HeapWordSize / K, 238 _max_tlab_size * HeapWordSize / K, 239 ergo_tlab * HeapWordSize / K, 240 size * HeapWordSize / K); 241 } 242 243 // All prepared, let's do it! 244 HeapWord* res = allocate_work(size); 245 246 if (res != NULL) { 247 // Allocation successful 248 *actual_size = size; 249 if (EpsilonElasticTLABDecay) { 250 EpsilonThreadLocalData::set_last_tlab_time(thread, time); 251 } 252 if (EpsilonElasticTLAB && !fits) { 253 // If we requested expansion, this is our new ergonomic TLAB size 254 EpsilonThreadLocalData::set_ergo_tlab_size(thread, size); 255 } 256 } else { 257 // Allocation failed, reset ergonomics to try and fit smaller TLABs 258 if (EpsilonElasticTLAB) { 259 EpsilonThreadLocalData::set_ergo_tlab_size(thread, 0); 260 } 261 } 262 263 return res; 264 } 265 266 HeapWord* EpsilonHeap::mem_allocate(size_t size, bool *gc_overhead_limit_was_exceeded) { 267 *gc_overhead_limit_was_exceeded = false; 268 return allocate_work(size); 269 } 270 271 void EpsilonHeap::collect(GCCause::Cause cause) { 272 switch (cause) { 273 case GCCause::_metadata_GC_threshold: 274 case GCCause::_metadata_GC_clear_soft_refs: 275 // Receiving these causes means the VM itself entered the safepoint for metadata collection. 276 // While Epsilon does not do GC, it has to perform sizing adjustments, otherwise we would 277 // re-enter the safepoint again very soon. 278 279 assert(SafepointSynchronize::is_at_safepoint(), "Expected at safepoint"); 280 log_info(gc)("GC request for \"%s\" is handled", GCCause::to_string(cause)); 281 MetaspaceGC::compute_new_size(); 282 print_metaspace_info(); 283 break; 284 default: 285 log_info(gc)("GC request for \"%s\" is ignored", GCCause::to_string(cause)); 286 } 287 _monitoring_support->update_counters(); 288 } 289 290 void EpsilonHeap::do_full_collection(bool clear_all_soft_refs) { 291 collect(gc_cause()); 292 } 293 294 void EpsilonHeap::object_iterate(ObjectClosure *cl) { 295 _space->object_iterate(cl); 296 } 297 298 void EpsilonHeap::print_on(outputStream *st) const { 299 st->print_cr("Epsilon Heap"); 300 301 // Cast away constness: 302 ((VirtualSpace)_virtual_space).print_on(st); 303 304 st->print_cr("Allocation space:"); 305 _space->print_on(st); 306 307 MetaspaceUtils::print_on(st); 308 } 309 310 bool EpsilonHeap::print_location(outputStream* st, void* addr) const { 311 return BlockLocationPrinter<EpsilonHeap>::print_location(st, addr); 312 } 313 314 void EpsilonHeap::print_tracing_info() const { 315 print_heap_info(used()); 316 print_metaspace_info(); 317 } 318 319 void EpsilonHeap::print_heap_info(size_t used) const { 320 size_t reserved = max_capacity(); 321 size_t committed = capacity(); 322 323 if (reserved != 0) { 324 log_info(gc)("Heap: " SIZE_FORMAT "%s reserved, " SIZE_FORMAT "%s (%.2f%%) committed, " 325 SIZE_FORMAT "%s (%.2f%%) used", 326 byte_size_in_proper_unit(reserved), proper_unit_for_byte_size(reserved), 327 byte_size_in_proper_unit(committed), proper_unit_for_byte_size(committed), 328 committed * 100.0 / reserved, 329 byte_size_in_proper_unit(used), proper_unit_for_byte_size(used), 330 used * 100.0 / reserved); 331 } else { 332 log_info(gc)("Heap: no reliable data"); 333 } 334 } 335 336 void EpsilonHeap::print_metaspace_info() const { 337 size_t reserved = MetaspaceUtils::reserved_bytes(); 338 size_t committed = MetaspaceUtils::committed_bytes(); 339 size_t used = MetaspaceUtils::used_bytes(); 340 341 if (reserved != 0) { 342 log_info(gc, metaspace)("Metaspace: " SIZE_FORMAT "%s reserved, " SIZE_FORMAT "%s (%.2f%%) committed, " 343 SIZE_FORMAT "%s (%.2f%%) used", 344 byte_size_in_proper_unit(reserved), proper_unit_for_byte_size(reserved), 345 byte_size_in_proper_unit(committed), proper_unit_for_byte_size(committed), 346 committed * 100.0 / reserved, 347 byte_size_in_proper_unit(used), proper_unit_for_byte_size(used), 348 used * 100.0 / reserved); 349 } else { 350 log_info(gc, metaspace)("Metaspace: no reliable data"); 351 } 352 }