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
initialize()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
50 initialize_reserved_region(heap_rs);
51
52 _space = new ContiguousSpace();
53 _space->initialize(committed_region, /* clear_space = */ true, /* mangle_space = */ true);
54
55 // Precompute hot fields
56 _max_tlab_size = MIN2(CollectedHeap::max_tlab_size(), align_object_size(EpsilonMaxTLABSize / HeapWordSize));
57 _step_counter_update = MIN2<size_t>(max_byte_size / 16, EpsilonUpdateCountersStep);
58 _step_heap_print = (EpsilonPrintHeapSteps == 0) ? SIZE_MAX : (max_byte_size / EpsilonPrintHeapSteps);
59 _decay_time_ns = (int64_t) EpsilonTLABDecayTime * NANOSECS_PER_MILLISEC;
60
61 // Enable monitoring
62 _monitoring_support = new EpsilonMonitoringSupport(this);
63 _last_counter_update = 0;
64 _last_heap_print = 0;
65
66 // Install barrier set
67 BarrierSet::set_barrier_set(new EpsilonBarrierSet());
68
69 // All done, print out the configuration
70 EpsilonInitLogger::print();
71
72 return JNI_OK;
73 }
74
post_initialize()75 void EpsilonHeap::post_initialize() {
76 CollectedHeap::post_initialize();
77 }
78
initialize_serviceability()79 void EpsilonHeap::initialize_serviceability() {
80 _pool = new EpsilonMemoryPool(this);
81 _memory_manager.add_pool(_pool);
82 }
83
memory_managers()84 GrowableArray<GCMemoryManager*> EpsilonHeap::memory_managers() {
85 GrowableArray<GCMemoryManager*> memory_managers(1);
86 memory_managers.append(&_memory_manager);
87 return memory_managers;
88 }
89
memory_pools()90 GrowableArray<MemoryPool*> EpsilonHeap::memory_pools() {
91 GrowableArray<MemoryPool*> memory_pools(1);
92 memory_pools.append(_pool);
93 return memory_pools;
94 }
95
unsafe_max_tlab_alloc(Thread * thr) const96 size_t EpsilonHeap::unsafe_max_tlab_alloc(Thread* thr) const {
97 // Return max allocatable TLAB size, and let allocation path figure out
98 // the actual allocation size. Note: result should be in bytes.
99 return _max_tlab_size * HeapWordSize;
100 }
101
heap()102 EpsilonHeap* EpsilonHeap::heap() {
103 return named_heap<EpsilonHeap>(CollectedHeap::Epsilon);
104 }
105
allocate_work(size_t size)106 HeapWord* EpsilonHeap::allocate_work(size_t size) {
107 assert(is_object_aligned(size), "Allocation size should be aligned: " SIZE_FORMAT, size);
108
109 HeapWord* res = NULL;
110 while (true) {
111 // Try to allocate, assume space is available
112 res = _space->par_allocate(size);
113 if (res != NULL) {
114 break;
115 }
116
117 // Allocation failed, attempt expansion, and retry:
118 {
119 MutexLocker ml(Heap_lock);
120
121 // Try to allocate under the lock, assume another thread was able to expand
122 res = _space->par_allocate(size);
123 if (res != NULL) {
124 break;
125 }
126
127 // Expand and loop back if space is available
128 size_t space_left = max_capacity() - capacity();
129 size_t want_space = MAX2(size, EpsilonMinHeapExpand);
130
131 if (want_space < space_left) {
132 // Enough space to expand in bulk:
133 bool expand = _virtual_space.expand_by(want_space);
134 assert(expand, "Should be able to expand");
135 } else if (size < space_left) {
136 // No space to expand in bulk, and this allocation is still possible,
137 // take all the remaining space:
138 bool expand = _virtual_space.expand_by(space_left);
139 assert(expand, "Should be able to expand");
140 } else {
141 // No space left:
142 return NULL;
143 }
144
145 _space->set_end((HeapWord *) _virtual_space.high());
146 }
147 }
148
149 size_t used = _space->used();
150
151 // Allocation successful, update counters
152 {
153 size_t last = _last_counter_update;
154 if ((used - last >= _step_counter_update) && Atomic::cmpxchg(&_last_counter_update, last, used) == last) {
155 _monitoring_support->update_counters();
156 }
157 }
158
159 // ...and print the occupancy line, if needed
160 {
161 size_t last = _last_heap_print;
162 if ((used - last >= _step_heap_print) && Atomic::cmpxchg(&_last_heap_print, last, used) == last) {
163 print_heap_info(used);
164 print_metaspace_info();
165 }
166 }
167
168 assert(is_object_aligned(res), "Object should be aligned: " PTR_FORMAT, p2i(res));
169 return res;
170 }
171
allocate_new_tlab(size_t min_size,size_t requested_size,size_t * actual_size)172 HeapWord* EpsilonHeap::allocate_new_tlab(size_t min_size,
173 size_t requested_size,
174 size_t* actual_size) {
175 Thread* thread = Thread::current();
176
177 // Defaults in case elastic paths are not taken
178 bool fits = true;
179 size_t size = requested_size;
180 size_t ergo_tlab = requested_size;
181 int64_t time = 0;
182
183 if (EpsilonElasticTLAB) {
184 ergo_tlab = EpsilonThreadLocalData::ergo_tlab_size(thread);
185
186 if (EpsilonElasticTLABDecay) {
187 int64_t last_time = EpsilonThreadLocalData::last_tlab_time(thread);
188 time = (int64_t) os::javaTimeNanos();
189
190 assert(last_time <= time, "time should be monotonic");
191
192 // If the thread had not allocated recently, retract the ergonomic size.
193 // This conserves memory when the thread had initial burst of allocations,
194 // and then started allocating only sporadically.
195 if (last_time != 0 && (time - last_time > _decay_time_ns)) {
196 ergo_tlab = 0;
197 EpsilonThreadLocalData::set_ergo_tlab_size(thread, 0);
198 }
199 }
200
201 // If we can fit the allocation under current TLAB size, do so.
202 // Otherwise, we want to elastically increase the TLAB size.
203 fits = (requested_size <= ergo_tlab);
204 if (!fits) {
205 size = (size_t) (ergo_tlab * EpsilonTLABElasticity);
206 }
207 }
208
209 // Always honor boundaries
210 size = clamp(size, min_size, _max_tlab_size);
211
212 // Always honor alignment
213 size = align_up(size, MinObjAlignment);
214
215 // Check that adjustments did not break local and global invariants
216 assert(is_object_aligned(size),
217 "Size honors object alignment: " SIZE_FORMAT, size);
218 assert(min_size <= size,
219 "Size honors min size: " SIZE_FORMAT " <= " SIZE_FORMAT, min_size, size);
220 assert(size <= _max_tlab_size,
221 "Size honors max size: " SIZE_FORMAT " <= " SIZE_FORMAT, size, _max_tlab_size);
222 assert(size <= CollectedHeap::max_tlab_size(),
223 "Size honors global max size: " SIZE_FORMAT " <= " SIZE_FORMAT, size, CollectedHeap::max_tlab_size());
224
225 if (log_is_enabled(Trace, gc)) {
226 ResourceMark rm;
227 log_trace(gc)("TLAB size for \"%s\" (Requested: " SIZE_FORMAT "K, Min: " SIZE_FORMAT
228 "K, Max: " SIZE_FORMAT "K, Ergo: " SIZE_FORMAT "K) -> " SIZE_FORMAT "K",
229 thread->name(),
230 requested_size * HeapWordSize / K,
231 min_size * HeapWordSize / K,
232 _max_tlab_size * HeapWordSize / K,
233 ergo_tlab * HeapWordSize / K,
234 size * HeapWordSize / K);
235 }
236
237 // All prepared, let's do it!
238 HeapWord* res = allocate_work(size);
239
240 if (res != NULL) {
241 // Allocation successful
242 *actual_size = size;
243 if (EpsilonElasticTLABDecay) {
244 EpsilonThreadLocalData::set_last_tlab_time(thread, time);
245 }
246 if (EpsilonElasticTLAB && !fits) {
247 // If we requested expansion, this is our new ergonomic TLAB size
248 EpsilonThreadLocalData::set_ergo_tlab_size(thread, size);
249 }
250 } else {
251 // Allocation failed, reset ergonomics to try and fit smaller TLABs
252 if (EpsilonElasticTLAB) {
253 EpsilonThreadLocalData::set_ergo_tlab_size(thread, 0);
254 }
255 }
256
257 return res;
258 }
259
mem_allocate(size_t size,bool * gc_overhead_limit_was_exceeded)260 HeapWord* EpsilonHeap::mem_allocate(size_t size, bool *gc_overhead_limit_was_exceeded) {
261 *gc_overhead_limit_was_exceeded = false;
262 return allocate_work(size);
263 }
264
collect(GCCause::Cause cause)265 void EpsilonHeap::collect(GCCause::Cause cause) {
266 switch (cause) {
267 case GCCause::_metadata_GC_threshold:
268 case GCCause::_metadata_GC_clear_soft_refs:
269 // Receiving these causes means the VM itself entered the safepoint for metadata collection.
270 // While Epsilon does not do GC, it has to perform sizing adjustments, otherwise we would
271 // re-enter the safepoint again very soon.
272
273 assert(SafepointSynchronize::is_at_safepoint(), "Expected at safepoint");
274 log_info(gc)("GC request for \"%s\" is handled", GCCause::to_string(cause));
275 MetaspaceGC::compute_new_size();
276 print_metaspace_info();
277 break;
278 default:
279 log_info(gc)("GC request for \"%s\" is ignored", GCCause::to_string(cause));
280 }
281 _monitoring_support->update_counters();
282 }
283
do_full_collection(bool clear_all_soft_refs)284 void EpsilonHeap::do_full_collection(bool clear_all_soft_refs) {
285 collect(gc_cause());
286 }
287
object_iterate(ObjectClosure * cl)288 void EpsilonHeap::object_iterate(ObjectClosure *cl) {
289 _space->object_iterate(cl);
290 }
291
print_on(outputStream * st) const292 void EpsilonHeap::print_on(outputStream *st) const {
293 st->print_cr("Epsilon Heap");
294
295 // Cast away constness:
296 ((VirtualSpace)_virtual_space).print_on(st);
297
298 if (_space != NULL) {
299 st->print_cr("Allocation space:");
300 _space->print_on(st);
301 }
302
303 MetaspaceUtils::print_on(st);
304 }
305
print_location(outputStream * st,void * addr) const306 bool EpsilonHeap::print_location(outputStream* st, void* addr) const {
307 return BlockLocationPrinter<EpsilonHeap>::print_location(st, addr);
308 }
309
print_tracing_info() const310 void EpsilonHeap::print_tracing_info() const {
311 print_heap_info(used());
312 print_metaspace_info();
313 }
314
print_heap_info(size_t used) const315 void EpsilonHeap::print_heap_info(size_t used) const {
316 size_t reserved = max_capacity();
317 size_t committed = capacity();
318
319 if (reserved != 0) {
320 log_info(gc)("Heap: " SIZE_FORMAT "%s reserved, " SIZE_FORMAT "%s (%.2f%%) committed, "
321 SIZE_FORMAT "%s (%.2f%%) used",
322 byte_size_in_proper_unit(reserved), proper_unit_for_byte_size(reserved),
323 byte_size_in_proper_unit(committed), proper_unit_for_byte_size(committed),
324 committed * 100.0 / reserved,
325 byte_size_in_proper_unit(used), proper_unit_for_byte_size(used),
326 used * 100.0 / reserved);
327 } else {
328 log_info(gc)("Heap: no reliable data");
329 }
330 }
331
print_metaspace_info() const332 void EpsilonHeap::print_metaspace_info() const {
333 size_t reserved = MetaspaceUtils::reserved_bytes();
334 size_t committed = MetaspaceUtils::committed_bytes();
335 size_t used = MetaspaceUtils::used_bytes();
336
337 if (reserved != 0) {
338 log_info(gc, metaspace)("Metaspace: " SIZE_FORMAT "%s reserved, " SIZE_FORMAT "%s (%.2f%%) committed, "
339 SIZE_FORMAT "%s (%.2f%%) used",
340 byte_size_in_proper_unit(reserved), proper_unit_for_byte_size(reserved),
341 byte_size_in_proper_unit(committed), proper_unit_for_byte_size(committed),
342 committed * 100.0 / reserved,
343 byte_size_in_proper_unit(used), proper_unit_for_byte_size(used),
344 used * 100.0 / reserved);
345 } else {
346 log_info(gc, metaspace)("Metaspace: no reliable data");
347 }
348 }
349