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 "memory/allocation.hpp" 29 #include "memory/allocation.inline.hpp" 30 #include "memory/resourceArea.hpp" 31 32 jint EpsilonHeap::initialize() { 33 size_t init_byte_size = _policy->initial_heap_byte_size(); 34 size_t max_byte_size = _policy->max_heap_byte_size(); 35 36 // Initialize backing storage 37 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, _policy->heap_alignment()); 38 _virtual_space.initialize(heap_rs, init_byte_size); 39 40 MemRegion committed_region((HeapWord*)_virtual_space.low(), (HeapWord*)_virtual_space.high()); 41 MemRegion reserved_region((HeapWord*)_virtual_space.low_boundary(), (HeapWord*)_virtual_space.high_boundary()); 42 43 initialize_reserved_region(reserved_region.start(), reserved_region.end()); 44 45 _space = new ContiguousSpace(); 46 _space->initialize(committed_region, /* clear_space = */ true, /* mangle_space = */ true); 47 48 // Precompute hot fields 49 _max_tlab_size = MIN2(CollectedHeap::max_tlab_size(), EpsilonMaxTLABSize / HeapWordSize); 50 _step_counter_update = MIN2<size_t>(max_byte_size / 16, EpsilonUpdateCountersStep); 51 _step_heap_print = (EpsilonPrintHeapStep == 0) ? SIZE_MAX : (max_byte_size / EpsilonPrintHeapStep); 52 _decay_time_ns = (int64_t) EpsilonTLABDecayTime * NANOSECS_PER_MILLISEC; 53 54 // Enable monitoring 55 _monitoring_support = new EpsilonMonitoringSupport(this); 56 _last_counter_update = 0; 57 _last_heap_print = 0; 58 59 // Install barrier set 60 BarrierSet::set_barrier_set(new EpsilonBarrierSet()); 61 62 // All done, print out the configuration 63 if (init_byte_size != max_byte_size) { 64 log_info(gc)("Resizeable heap; starting at " SIZE_FORMAT "M, max: " SIZE_FORMAT "M, step: " SIZE_FORMAT "M", 65 init_byte_size / M, max_byte_size / M, EpsilonMinHeapExpand / M); 66 } else { 67 log_info(gc)("Non-resizeable heap; start/max: " SIZE_FORMAT "M", init_byte_size / M); 68 } 69 70 if (UseTLAB) { 71 log_info(gc)("Using TLAB allocation; max: " SIZE_FORMAT "K", _max_tlab_size * HeapWordSize / K); 72 if (EpsilonElasticTLAB) { 73 log_info(gc)("Elastic TLABs enabled; elasticity: %.2fx", EpsilonTLABElasticity); 74 } 75 if (EpsilonElasticTLABDecay) { 76 log_info(gc)("Elastic TLABs decay enabled; decay time: " SIZE_FORMAT "ms", EpsilonTLABDecayTime); 77 } 78 } else { 79 log_info(gc)("Not using TLAB allocation"); 80 } 81 82 return JNI_OK; 83 } 84 85 void EpsilonHeap::post_initialize() { 86 CollectedHeap::post_initialize(); 87 } 88 89 void EpsilonHeap::initialize_serviceability() { 90 _pool = new EpsilonMemoryPool(this); 91 _memory_manager.add_pool(_pool); 92 } 93 94 GrowableArray<GCMemoryManager*> EpsilonHeap::memory_managers() { 95 GrowableArray<GCMemoryManager*> memory_managers(1); 96 memory_managers.append(&_memory_manager); 97 return memory_managers; 98 } 99 100 GrowableArray<MemoryPool*> EpsilonHeap::memory_pools() { 101 GrowableArray<MemoryPool*> memory_pools(1); 102 memory_pools.append(_pool); 103 return memory_pools; 104 } 105 106 size_t EpsilonHeap::unsafe_max_tlab_alloc(Thread* thr) const { 107 // Return max allocatable TLAB size, and let allocation path figure out 108 // the actual TLAB allocation size. 109 return _max_tlab_size; 110 } 111 112 EpsilonHeap* EpsilonHeap::heap() { 113 CollectedHeap* heap = Universe::heap(); 114 assert(heap != NULL, "Uninitialized access to EpsilonHeap::heap()"); 115 assert(heap->kind() == CollectedHeap::Epsilon, "Not an Epsilon heap"); 116 return (EpsilonHeap*)heap; 117 } 118 119 HeapWord* EpsilonHeap::allocate_work(size_t size) { 120 HeapWord* res = _space->par_allocate(size); 121 122 while (res == NULL) { 123 // Allocation failed, attempt expansion, and retry: 124 MutexLockerEx ml(Heap_lock); 125 126 size_t space_left = max_capacity() - capacity(); 127 size_t want_space = MAX2(size, EpsilonMinHeapExpand); 128 129 if (want_space < space_left) { 130 // Enough space to expand in bulk: 131 bool expand = _virtual_space.expand_by(want_space); 132 assert(expand, "Should be able to expand"); 133 } else if (size < space_left) { 134 // No space to expand in bulk, and this allocation is still possible, 135 // take all the remaining space: 136 bool expand = _virtual_space.expand_by(space_left); 137 assert(expand, "Should be able to expand"); 138 } else { 139 // No space left: 140 return NULL; 141 } 142 143 _space->set_end((HeapWord *) _virtual_space.high()); 144 res = _space->par_allocate(size); 145 } 146 147 // Allocation successful, update counters 148 size_t used = _space->used(); 149 if (used - _last_counter_update >= _step_counter_update) { 150 _last_counter_update = used; 151 _monitoring_support->update_counters(); 152 } 153 154 // ...and print the occupancy line, if needed 155 if (used - _last_heap_print >= _step_heap_print) { 156 log_info(gc)("Heap: " SIZE_FORMAT "M reserved, " SIZE_FORMAT "M committed, " SIZE_FORMAT "M used", 157 max_capacity() / M, capacity() / M, used / M); 158 _last_heap_print = used; 159 } 160 161 return res; 162 } 163 164 HeapWord* EpsilonHeap::allocate_new_tlab(size_t min_size, 165 size_t requested_size, 166 size_t* actual_size) { 167 Thread* thread = Thread::current(); 168 169 // Defaults in case elastic paths are not taken 170 bool fits = true; 171 size_t size = requested_size; 172 size_t ergo_tlab = requested_size; 173 int64_t time = 0; 174 175 if (EpsilonElasticTLAB) { 176 ergo_tlab = EpsilonThreadLocalData::ergo_tlab_size(thread); 177 178 if (EpsilonElasticTLABDecay) { 179 int64_t last_time = EpsilonThreadLocalData::last_tlab_time(thread); 180 time = (int64_t) os::javaTimeNanos(); 181 182 assert(last_time <= time, "time should be monotonic"); 183 184 // If the thread had not allocated recently, retract the ergonomic size. 185 // This conserves memory when the thread had initial burst of allocations, 186 // and then started allocating only sporadically. 187 if (last_time != 0 && (time - last_time > _decay_time_ns)) { 188 ergo_tlab = 0; 189 EpsilonThreadLocalData::set_ergo_tlab_size(thread, 0); 190 } 191 } 192 193 // If we can fit the allocation under current TLAB size, do so. 194 // Otherwise, we want to elastically increase the TLAB size. 195 fits = (requested_size <= ergo_tlab); 196 if (!fits) { 197 size = (size_t) (ergo_tlab * EpsilonTLABElasticity); 198 } 199 } 200 201 // Always honor boundaries 202 size = MAX2(min_size, MIN2(_max_tlab_size, size)); 203 204 if (log_is_enabled(Trace, gc)) { 205 ResourceMark rm; 206 log_trace(gc)("TLAB size for \"%s\" (Requested: " SIZE_FORMAT "K, Min: " SIZE_FORMAT 207 "K, Max: " SIZE_FORMAT "K, Ergo: " SIZE_FORMAT "K) -> " SIZE_FORMAT "K", 208 thread->name(), 209 requested_size * HeapWordSize / K, 210 min_size * HeapWordSize / K, 211 _max_tlab_size * HeapWordSize / K, 212 ergo_tlab * HeapWordSize / K, 213 size * HeapWordSize / K); 214 } 215 216 // All prepared, let's do it! 217 HeapWord* res = allocate_work(size); 218 219 if (res != NULL) { 220 // Allocation successful 221 *actual_size = size; 222 if (EpsilonElasticTLABDecay) { 223 EpsilonThreadLocalData::set_last_tlab_time(thread, time); 224 } 225 if (EpsilonElasticTLAB && !fits) { 226 // If we requested expansion, this is our new ergonomic TLAB size 227 EpsilonThreadLocalData::set_ergo_tlab_size(thread, size); 228 } 229 } else { 230 // Allocation failed, reset ergonomics to try and fit smaller TLABs 231 if (EpsilonElasticTLAB) { 232 EpsilonThreadLocalData::set_ergo_tlab_size(thread, 0); 233 } 234 } 235 236 return res; 237 } 238 239 HeapWord* EpsilonHeap::mem_allocate(size_t size, bool *gc_overhead_limit_was_exceeded) { 240 *gc_overhead_limit_was_exceeded = false; 241 return allocate_work(size); 242 } 243 244 void EpsilonHeap::collect(GCCause::Cause cause) { 245 log_info(gc)("GC request for \"%s\" is ignored", GCCause::to_string(cause)); 246 _monitoring_support->update_counters(); 247 } 248 249 void EpsilonHeap::do_full_collection(bool clear_all_soft_refs) { 250 log_info(gc)("Full GC request for \"%s\" is ignored", GCCause::to_string(gc_cause())); 251 _monitoring_support->update_counters(); 252 } 253 254 void EpsilonHeap::safe_object_iterate(ObjectClosure *cl) { 255 _space->safe_object_iterate(cl); 256 } 257 258 void EpsilonHeap::print_on(outputStream *st) const { 259 st->print_cr("Epsilon Heap"); 260 261 // Cast away constness: 262 ((VirtualSpace)_virtual_space).print_on(st); 263 264 st->print_cr("Allocation space:"); 265 _space->print_on(st); 266 } 267 268 void EpsilonHeap::print_tracing_info() const { 269 Log(gc) log; 270 size_t allocated_kb = used() / K; 271 log.info("Total allocated: " SIZE_FORMAT " KB", 272 allocated_kb); 273 log.info("Average allocation rate: " SIZE_FORMAT " KB/sec", 274 (size_t)(allocated_kb * NANOSECS_PER_SEC / os::elapsed_counter())); 275 }