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