1 /*
2 * Copyright (c) 2013, 2019, 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 "memory/allocation.hpp"
26 #include "memory/universe.hpp"
27
28 #include "gc/shared/gcArguments.hpp"
29 #include "gc/shared/gcTimer.hpp"
30 #include "gc/shared/gcTraceTime.inline.hpp"
31 #include "gc/shared/memAllocator.hpp"
32 #include "gc/shared/parallelCleaning.hpp"
33 #include "gc/shared/plab.hpp"
34
35 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
36 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
37 #include "gc/shenandoah/shenandoahForwarding.hpp"
38 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
39 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
40 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
41 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
42 #include "gc/shenandoah/shenandoahControlThread.hpp"
43 #include "gc/shenandoah/shenandoahFreeSet.hpp"
44 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
45 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
46 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
47 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
48 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
49 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
50 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
51 #include "gc/shenandoah/shenandoahMetrics.hpp"
52 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
53 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
54 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
55 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
56 #include "gc/shenandoah/shenandoahStringDedup.hpp"
57 #include "gc/shenandoah/shenandoahUtils.hpp"
58 #include "gc/shenandoah/shenandoahVerifier.hpp"
59 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
60 #include "gc/shenandoah/shenandoahVMOperations.hpp"
61 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
62 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
66 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
67 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
68 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
69 #include "memory/metaspace.hpp"
70 #include "oops/compressedOops.inline.hpp"
71 #include "runtime/globals.hpp"
72 #include "runtime/interfaceSupport.inline.hpp"
73 #include "runtime/safepointMechanism.hpp"
74 #include "runtime/vmThread.hpp"
75 #include "services/mallocTracker.hpp"
76
77 #ifdef ASSERT
78 template <class T>
79 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
80 T o = RawAccess<>::oop_load(p);
81 if (! CompressedOops::is_null(o)) {
82 oop obj = CompressedOops::decode_not_null(o);
83 shenandoah_assert_not_forwarded(p, obj);
84 }
85 }
86
87 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
88 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
89 #endif
90
91 class ShenandoahPretouchHeapTask : public AbstractGangTask {
92 private:
93 ShenandoahRegionIterator _regions;
94 const size_t _page_size;
95 public:
96 ShenandoahPretouchHeapTask(size_t page_size) :
97 AbstractGangTask("Shenandoah Pretouch Heap"),
98 _page_size(page_size) {}
99
100 virtual void work(uint worker_id) {
101 ShenandoahHeapRegion* r = _regions.next();
102 while (r != NULL) {
103 os::pretouch_memory(r->bottom(), r->end(), _page_size);
104 r = _regions.next();
105 }
106 }
107 };
108
109 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
110 private:
111 ShenandoahRegionIterator _regions;
112 char* _bitmap_base;
113 const size_t _bitmap_size;
114 const size_t _page_size;
115 public:
116 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
117 AbstractGangTask("Shenandoah Pretouch Bitmap"),
118 _bitmap_base(bitmap_base),
119 _bitmap_size(bitmap_size),
120 _page_size(page_size) {}
121
122 virtual void work(uint worker_id) {
123 ShenandoahHeapRegion* r = _regions.next();
124 while (r != NULL) {
125 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
126 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
127 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
128
129 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
130
131 r = _regions.next();
132 }
133 }
134 };
135
136 jint ShenandoahHeap::initialize() {
137 ShenandoahForwarding::initial_checks();
138
139 initialize_heuristics();
140
141 //
142 // Figure out heap sizing
143 //
144
145 size_t init_byte_size = InitialHeapSize;
146 size_t min_byte_size = MinHeapSize;
147 size_t max_byte_size = MaxHeapSize;
148 size_t heap_alignment = HeapAlignment;
149
150 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
151
152 if (ShenandoahAlwaysPreTouch) {
153 // Enabled pre-touch means the entire heap is committed right away.
154 init_byte_size = max_byte_size;
155 }
156
157 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
158 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
159
160 _num_regions = ShenandoahHeapRegion::region_count();
161
162 size_t num_committed_regions = init_byte_size / reg_size_bytes;
163 num_committed_regions = MIN2(num_committed_regions, _num_regions);
164 assert(num_committed_regions <= _num_regions, "sanity");
165 _initial_size = num_committed_regions * reg_size_bytes;
166
167 size_t num_min_regions = min_byte_size / reg_size_bytes;
168 num_min_regions = MIN2(num_min_regions, _num_regions);
169 assert(num_min_regions <= _num_regions, "sanity");
170 _minimum_size = num_min_regions * reg_size_bytes;
171
172 _committed = _initial_size;
173
174 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
175 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
176
177 //
178 // Reserve and commit memory for heap
179 //
180
181 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
182 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
183 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
184 _heap_region_special = heap_rs.special();
185
186 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
187 "Misaligned heap: " PTR_FORMAT, p2i(base()));
188
189 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
190 if (!_heap_region_special) {
191 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
192 "Cannot commit heap memory");
193 }
194
195 //
196 // Reserve and commit memory for bitmap(s)
197 //
198
199 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
200 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
201
202 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
203
204 guarantee(bitmap_bytes_per_region != 0,
205 "Bitmap bytes per region should not be zero");
206 guarantee(is_power_of_2(bitmap_bytes_per_region),
207 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
208
209 if (bitmap_page_size > bitmap_bytes_per_region) {
210 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
211 _bitmap_bytes_per_slice = bitmap_page_size;
212 } else {
213 _bitmap_regions_per_slice = 1;
214 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
215 }
216
217 guarantee(_bitmap_regions_per_slice >= 1,
218 "Should have at least one region per slice: " SIZE_FORMAT,
219 _bitmap_regions_per_slice);
220
221 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
222 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
223 _bitmap_bytes_per_slice, bitmap_page_size);
224
225 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
226 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
227 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
228 _bitmap_region_special = bitmap.special();
229
230 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
231 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
232 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
233 if (!_bitmap_region_special) {
234 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
235 "Cannot commit bitmap memory");
236 }
237
238 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
239
240 if (ShenandoahVerify) {
241 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
242 if (!verify_bitmap.special()) {
243 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
244 "Cannot commit verification bitmap memory");
245 }
246 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
247 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
248 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
249 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
250 }
251
252 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
253 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
254 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
255 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
256 _aux_bitmap_region_special = aux_bitmap.special();
257 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
258
259 //
260 // Create regions and region sets
261 //
262
263 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
264 _free_set = new ShenandoahFreeSet(this, _num_regions);
265 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
266
267 {
268 ShenandoahHeapLocker locker(lock());
269
270 size_t size_words = ShenandoahHeapRegion::region_size_words();
271
272 for (size_t i = 0; i < _num_regions; i++) {
273 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
274 bool is_committed = i < num_committed_regions;
275 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
276
277 _marking_context->initialize_top_at_mark_start(r);
278 _regions[i] = r;
279 assert(!collection_set()->is_in(i), "New region should not be in collection set");
280 }
281
282 // Initialize to complete
283 _marking_context->mark_complete();
284
285 _free_set->rebuild();
286 }
287
288 if (ShenandoahAlwaysPreTouch) {
289 assert(!AlwaysPreTouch, "Should have been overridden");
290
291 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
292 // before initialize() below zeroes it with initializing thread. For any given region,
293 // we touch the region and the corresponding bitmaps from the same thread.
294 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
295
296 size_t pretouch_heap_page_size = heap_page_size;
297 size_t pretouch_bitmap_page_size = bitmap_page_size;
298
299 #ifdef LINUX
300 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
301 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
302 // them into huge one. Therefore, we need to pretouch with smaller pages.
303 if (UseTransparentHugePages) {
304 pretouch_heap_page_size = (size_t)os::vm_page_size();
305 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
306 }
307 #endif
308
309 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
310 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
311
312 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
313 _num_regions, pretouch_bitmap_page_size);
314 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
315 _workers->run_task(&bcl);
316
317 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
318 _num_regions, pretouch_heap_page_size);
319 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
320 _workers->run_task(&hcl);
321 }
322
323 //
324 // Initialize the rest of GC subsystems
325 //
326
327 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
328 for (uint worker = 0; worker < _max_workers; worker++) {
329 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
330 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
331 }
332
333 // The call below uses stuff (the SATB* things) that are in G1, but probably
334 // belong into a shared location.
335 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
336 SATB_Q_CBL_mon,
337 20 /* G1SATBProcessCompletedThreshold */,
338 60 /* G1SATBBufferEnqueueingThresholdPercent */);
339
340 _monitoring_support = new ShenandoahMonitoringSupport(this);
341 _phase_timings = new ShenandoahPhaseTimings();
342 ShenandoahStringDedup::initialize();
343 ShenandoahCodeRoots::initialize();
344
345 if (ShenandoahAllocationTrace) {
346 _alloc_tracker = new ShenandoahAllocTracker();
347 }
348
349 if (ShenandoahPacing) {
350 _pacer = new ShenandoahPacer(this);
351 _pacer->setup_for_idle();
352 } else {
353 _pacer = NULL;
354 }
355
356 _traversal_gc = heuristics()->can_do_traversal_gc() ?
357 new ShenandoahTraversalGC(this, _num_regions) :
358 NULL;
359
360 _control_thread = new ShenandoahControlThread();
361
362 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
363 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
364 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
365 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
366 );
367
368 log_info(gc, init)("Safepointing mechanism: %s",
369 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
370 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
371
372 return JNI_OK;
373 }
374
375 void ShenandoahHeap::initialize_heuristics() {
376 if (ShenandoahGCHeuristics != NULL) {
377 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
378 _heuristics = new ShenandoahAggressiveHeuristics();
379 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
380 _heuristics = new ShenandoahStaticHeuristics();
381 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
382 _heuristics = new ShenandoahAdaptiveHeuristics();
383 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
384 _heuristics = new ShenandoahPassiveHeuristics();
385 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
386 _heuristics = new ShenandoahCompactHeuristics();
387 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
388 _heuristics = new ShenandoahTraversalHeuristics();
389 } else {
390 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
391 }
392
393 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
394 vm_exit_during_initialization(
395 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
396 _heuristics->name()));
397 }
398 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
399 vm_exit_during_initialization(
400 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
401 _heuristics->name()));
402 }
403 log_info(gc, init)("Shenandoah heuristics: %s",
404 _heuristics->name());
405 } else {
406 ShouldNotReachHere();
407 }
408
409 }
410
411 #ifdef _MSC_VER
412 #pragma warning( push )
413 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
414 #endif
415
416 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
417 CollectedHeap(),
418 _initial_size(0),
419 _used(0),
420 _committed(0),
421 _bytes_allocated_since_gc_start(0),
422 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
423 _workers(NULL),
424 _safepoint_workers(NULL),
425 _heap_region_special(false),
426 _num_regions(0),
427 _regions(NULL),
428 _update_refs_iterator(this),
429 _control_thread(NULL),
430 _shenandoah_policy(policy),
431 _heuristics(NULL),
432 _free_set(NULL),
433 _scm(new ShenandoahConcurrentMark()),
434 _traversal_gc(NULL),
435 _full_gc(new ShenandoahMarkCompact()),
436 _pacer(NULL),
437 _verifier(NULL),
438 _alloc_tracker(NULL),
439 _phase_timings(NULL),
440 _monitoring_support(NULL),
441 _memory_pool(NULL),
442 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
443 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
444 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
445 _soft_ref_policy(),
446 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
447 _ref_processor(NULL),
448 _marking_context(NULL),
449 _bitmap_size(0),
450 _bitmap_regions_per_slice(0),
451 _bitmap_bytes_per_slice(0),
452 _bitmap_region_special(false),
453 _aux_bitmap_region_special(false),
454 _liveness_cache(NULL),
455 _collection_set(NULL)
456 {
457 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
458 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
459
460 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
461
462 _max_workers = MAX2(_max_workers, 1U);
463 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
464 /* are_GC_task_threads */ true,
465 /* are_ConcurrentGC_threads */ true);
466 if (_workers == NULL) {
467 vm_exit_during_initialization("Failed necessary allocation.");
468 } else {
469 _workers->initialize_workers();
470 }
471
472 if (ShenandoahParallelSafepointThreads > 1) {
473 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
474 ShenandoahParallelSafepointThreads,
475 /* are_GC_task_threads */ false,
476 /* are_ConcurrentGC_threads */ false);
477 _safepoint_workers->initialize_workers();
478 }
479 }
480
481 #ifdef _MSC_VER
482 #pragma warning( pop )
483 #endif
484
485 class ShenandoahResetBitmapTask : public AbstractGangTask {
486 private:
487 ShenandoahRegionIterator _regions;
488
489 public:
490 ShenandoahResetBitmapTask() :
491 AbstractGangTask("Parallel Reset Bitmap Task") {}
492
493 void work(uint worker_id) {
494 ShenandoahHeapRegion* region = _regions.next();
495 ShenandoahHeap* heap = ShenandoahHeap::heap();
496 ShenandoahMarkingContext* const ctx = heap->marking_context();
497 while (region != NULL) {
498 if (heap->is_bitmap_slice_committed(region)) {
499 ctx->clear_bitmap(region);
500 }
501 region = _regions.next();
502 }
503 }
504 };
505
506 void ShenandoahHeap::reset_mark_bitmap() {
507 assert_gc_workers(_workers->active_workers());
508 mark_incomplete_marking_context();
509
510 ShenandoahResetBitmapTask task;
511 _workers->run_task(&task);
512 }
513
514 void ShenandoahHeap::print_on(outputStream* st) const {
515 st->print_cr("Shenandoah Heap");
516 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
517 max_capacity() / K, committed() / K, used() / K);
518 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
519 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
520
521 st->print("Status: ");
522 if (has_forwarded_objects()) st->print("has forwarded objects, ");
523 if (is_concurrent_mark_in_progress()) st->print("marking, ");
524 if (is_evacuation_in_progress()) st->print("evacuating, ");
525 if (is_update_refs_in_progress()) st->print("updating refs, ");
526 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
527 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
528 if (is_full_gc_in_progress()) st->print("full gc, ");
529 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
530
531 if (cancelled_gc()) {
532 st->print("cancelled");
533 } else {
534 st->print("not cancelled");
535 }
536 st->cr();
537
538 st->print_cr("Reserved region:");
539 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
540 p2i(reserved_region().start()),
541 p2i(reserved_region().end()));
542
543 ShenandoahCollectionSet* cset = collection_set();
544 st->print_cr("Collection set:");
545 if (cset != NULL) {
546 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
547 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
548 } else {
549 st->print_cr(" (NULL)");
550 }
551
552 st->cr();
553 MetaspaceUtils::print_on(st);
554
555 if (Verbose) {
556 print_heap_regions_on(st);
557 }
558 }
559
560 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
561 public:
562 void do_thread(Thread* thread) {
563 assert(thread != NULL, "Sanity");
564 assert(thread->is_Worker_thread(), "Only worker thread expected");
565 ShenandoahThreadLocalData::initialize_gclab(thread);
566 }
567 };
568
569 void ShenandoahHeap::post_initialize() {
570 CollectedHeap::post_initialize();
571 MutexLocker ml(Threads_lock);
572
573 ShenandoahInitWorkerGCLABClosure init_gclabs;
574 _workers->threads_do(&init_gclabs);
575
576 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
577 // Now, we will let WorkGang to initialize gclab when new worker is created.
578 _workers->set_initialize_gclab();
579
580 _scm->initialize(_max_workers);
581 _full_gc->initialize(_gc_timer);
582
583 ref_processing_init();
584
585 _heuristics->initialize();
586 }
587
588 size_t ShenandoahHeap::used() const {
589 return OrderAccess::load_acquire(&_used);
590 }
591
592 size_t ShenandoahHeap::committed() const {
593 OrderAccess::acquire();
594 return _committed;
595 }
596
597 void ShenandoahHeap::increase_committed(size_t bytes) {
598 assert_heaplock_or_safepoint();
599 _committed += bytes;
600 }
601
602 void ShenandoahHeap::decrease_committed(size_t bytes) {
603 assert_heaplock_or_safepoint();
604 _committed -= bytes;
605 }
606
607 void ShenandoahHeap::increase_used(size_t bytes) {
608 Atomic::add(bytes, &_used);
609 }
610
611 void ShenandoahHeap::set_used(size_t bytes) {
612 OrderAccess::release_store_fence(&_used, bytes);
613 }
614
615 void ShenandoahHeap::decrease_used(size_t bytes) {
616 assert(used() >= bytes, "never decrease heap size by more than we've left");
617 Atomic::sub(bytes, &_used);
618 }
619
620 void ShenandoahHeap::increase_allocated(size_t bytes) {
621 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
622 }
623
624 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
625 size_t bytes = words * HeapWordSize;
626 if (!waste) {
627 increase_used(bytes);
628 }
629 increase_allocated(bytes);
630 if (ShenandoahPacing) {
631 control_thread()->pacing_notify_alloc(words);
632 if (waste) {
633 pacer()->claim_for_alloc(words, true);
634 }
635 }
636 }
637
638 size_t ShenandoahHeap::capacity() const {
639 return committed();
640 }
641
642 size_t ShenandoahHeap::max_capacity() const {
643 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
644 }
645
646 size_t ShenandoahHeap::min_capacity() const {
647 return _minimum_size;
648 }
649
650 size_t ShenandoahHeap::initial_capacity() const {
651 return _initial_size;
652 }
653
654 bool ShenandoahHeap::is_in(const void* p) const {
655 HeapWord* heap_base = (HeapWord*) base();
656 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
657 return p >= heap_base && p < last_region_end;
658 }
659
660 void ShenandoahHeap::op_uncommit(double shrink_before) {
661 assert (ShenandoahUncommit, "should be enabled");
662
663 // Application allocates from the beginning of the heap, and GC allocates at
664 // the end of it. It is more efficient to uncommit from the end, so that applications
665 // could enjoy the near committed regions. GC allocations are much less frequent,
666 // and therefore can accept the committing costs.
667
668 size_t count = 0;
669 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
670 ShenandoahHeapRegion* r = get_region(i - 1);
671 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
672 ShenandoahHeapLocker locker(lock());
673 if (r->is_empty_committed()) {
674 // Do not uncommit below minimal capacity
675 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
676 break;
677 }
678
679 r->make_uncommitted();
680 count++;
681 }
682 }
683 SpinPause(); // allow allocators to take the lock
684 }
685
686 if (count > 0) {
687 control_thread()->notify_heap_changed();
688 }
689 }
690
691 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
692 // New object should fit the GCLAB size
693 size_t min_size = MAX2(size, PLAB::min_size());
694
695 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
696 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
697 new_size = MIN2(new_size, PLAB::max_size());
698 new_size = MAX2(new_size, PLAB::min_size());
699
700 // Record new heuristic value even if we take any shortcut. This captures
701 // the case when moderately-sized objects always take a shortcut. At some point,
702 // heuristics should catch up with them.
703 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
704
705 if (new_size < size) {
706 // New size still does not fit the object. Fall back to shared allocation.
707 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
708 return NULL;
709 }
710
711 // Retire current GCLAB, and allocate a new one.
712 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
713 gclab->retire();
714
715 size_t actual_size = 0;
716 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
717 if (gclab_buf == NULL) {
718 return NULL;
719 }
720
721 assert (size <= actual_size, "allocation should fit");
722
723 if (ZeroTLAB) {
724 // ..and clear it.
725 Copy::zero_to_words(gclab_buf, actual_size);
726 } else {
727 // ...and zap just allocated object.
728 #ifdef ASSERT
729 // Skip mangling the space corresponding to the object header to
730 // ensure that the returned space is not considered parsable by
731 // any concurrent GC thread.
732 size_t hdr_size = oopDesc::header_size();
733 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
734 #endif // ASSERT
735 }
736 gclab->set_buf(gclab_buf, actual_size);
737 return gclab->allocate(size);
738 }
739
740 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
741 size_t requested_size,
742 size_t* actual_size) {
743 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
744 HeapWord* res = allocate_memory(req);
745 if (res != NULL) {
746 *actual_size = req.actual_size();
747 } else {
748 *actual_size = 0;
749 }
750 return res;
751 }
752
753 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
754 size_t word_size,
755 size_t* actual_size) {
756 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
757 HeapWord* res = allocate_memory(req);
758 if (res != NULL) {
759 *actual_size = req.actual_size();
760 } else {
761 *actual_size = 0;
762 }
763 return res;
764 }
765
766 ShenandoahHeap* ShenandoahHeap::heap() {
767 CollectedHeap* heap = Universe::heap();
768 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
769 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
770 return (ShenandoahHeap*) heap;
771 }
772
773 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
774 CollectedHeap* heap = Universe::heap();
775 return (ShenandoahHeap*) heap;
776 }
777
778 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
779 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
780
781 intptr_t pacer_epoch = 0;
782 bool in_new_region = false;
783 HeapWord* result = NULL;
784
785 if (req.is_mutator_alloc()) {
786 if (ShenandoahPacing) {
787 pacer()->pace_for_alloc(req.size());
788 pacer_epoch = pacer()->epoch();
789 }
790
791 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
792 result = allocate_memory_under_lock(req, in_new_region);
793 }
794
795 // Allocation failed, block until control thread reacted, then retry allocation.
796 //
797 // It might happen that one of the threads requesting allocation would unblock
798 // way later after GC happened, only to fail the second allocation, because
799 // other threads have already depleted the free storage. In this case, a better
800 // strategy is to try again, as long as GC makes progress.
801 //
802 // Then, we need to make sure the allocation was retried after at least one
803 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
804
805 size_t tries = 0;
806
807 while (result == NULL && _progress_last_gc.is_set()) {
808 tries++;
809 control_thread()->handle_alloc_failure(req.size());
810 result = allocate_memory_under_lock(req, in_new_region);
811 }
812
813 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
814 tries++;
815 control_thread()->handle_alloc_failure(req.size());
816 result = allocate_memory_under_lock(req, in_new_region);
817 }
818
819 } else {
820 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
821 result = allocate_memory_under_lock(req, in_new_region);
822 // Do not call handle_alloc_failure() here, because we cannot block.
823 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
824 }
825
826 if (in_new_region) {
827 control_thread()->notify_heap_changed();
828 }
829
830 if (result != NULL) {
831 size_t requested = req.size();
832 size_t actual = req.actual_size();
833
834 assert (req.is_lab_alloc() || (requested == actual),
835 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
836 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
837
838 if (req.is_mutator_alloc()) {
839 notify_mutator_alloc_words(actual, false);
840
841 // If we requested more than we were granted, give the rest back to pacer.
842 // This only matters if we are in the same pacing epoch: do not try to unpace
843 // over the budget for the other phase.
844 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
845 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
846 }
847 } else {
848 increase_used(actual*HeapWordSize);
849 }
850 }
851
852 return result;
853 }
854
855 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
856 ShenandoahHeapLocker locker(lock());
857 return _free_set->allocate(req, in_new_region);
858 }
859
860 class ShenandoahMemAllocator : public MemAllocator {
861 private:
862 MemAllocator& _initializer;
863 public:
864 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
865 MemAllocator(klass, word_size + ShenandoahForwarding::word_size(), thread),
866 _initializer(initializer) {}
867
868 protected:
869 virtual HeapWord* mem_allocate(Allocation& allocation) const {
870 HeapWord* result = MemAllocator::mem_allocate(allocation);
871 // Initialize brooks-pointer
872 if (result != NULL) {
873 result += ShenandoahForwarding::word_size();
874 ShenandoahForwarding::initialize(oop(result));
875 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
876 }
877 return result;
878 }
879
880 virtual oop initialize(HeapWord* mem) const {
881 return _initializer.initialize(mem);
882 }
883 };
884
885 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
886 ObjAllocator initializer(klass, size, THREAD);
887 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
888 return allocator.allocate();
889 }
890
891 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
892 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
893 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
894 return allocator.allocate();
895 }
896
897 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
898 ClassAllocator initializer(klass, size, THREAD);
899 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
900 return allocator.allocate();
901 }
902
903 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
904 bool* gc_overhead_limit_was_exceeded) {
905 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
906 return allocate_memory(req);
907 }
908
909 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
910 size_t size,
911 Metaspace::MetadataType mdtype) {
912 MetaWord* result;
913
914 // Inform metaspace OOM to GC heuristics if class unloading is possible.
915 if (heuristics()->can_unload_classes()) {
916 ShenandoahHeuristics* h = heuristics();
917 h->record_metaspace_oom();
918 }
919
920 // Expand and retry allocation
921 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
922 if (result != NULL) {
923 return result;
924 }
925
926 // Start full GC
927 collect(GCCause::_metadata_GC_clear_soft_refs);
928
929 // Retry allocation
930 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
931 if (result != NULL) {
932 return result;
933 }
934
935 // Expand and retry allocation
936 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
937 if (result != NULL) {
938 return result;
939 }
940
941 // Out of memory
942 return NULL;
943 }
944
945 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
946 HeapWord* obj = tlab_post_allocation_setup(start);
947 CollectedHeap::fill_with_object(obj, end);
948 }
949
950 size_t ShenandoahHeap::min_dummy_object_size() const {
951 return CollectedHeap::min_dummy_object_size() + ShenandoahForwarding::word_size();
952 }
953
954 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
955 private:
956 ShenandoahHeap* const _heap;
957 Thread* const _thread;
958 public:
959 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
960 _heap(heap), _thread(Thread::current()) {}
961
962 void do_object(oop p) {
963 shenandoah_assert_marked(NULL, p);
964 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
965 _heap->evacuate_object(p, _thread);
966 }
967 }
968 };
969
970 class ShenandoahEvacuationTask : public AbstractGangTask {
971 private:
972 ShenandoahHeap* const _sh;
973 ShenandoahCollectionSet* const _cs;
974 bool _concurrent;
975 public:
976 ShenandoahEvacuationTask(ShenandoahHeap* sh,
977 ShenandoahCollectionSet* cs,
978 bool concurrent) :
979 AbstractGangTask("Parallel Evacuation Task"),
980 _sh(sh),
981 _cs(cs),
982 _concurrent(concurrent)
983 {}
984
985 void work(uint worker_id) {
986 if (_concurrent) {
987 ShenandoahConcurrentWorkerSession worker_session(worker_id);
988 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
989 ShenandoahEvacOOMScope oom_evac_scope;
990 do_work();
991 } else {
992 ShenandoahParallelWorkerSession worker_session(worker_id);
993 ShenandoahEvacOOMScope oom_evac_scope;
994 do_work();
995 }
996 }
997
998 private:
999 void do_work() {
1000 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
1001 ShenandoahHeapRegion* r;
1002 while ((r =_cs->claim_next()) != NULL) {
1003 assert(r->has_live(), "all-garbage regions are reclaimed early");
1004 _sh->marked_object_iterate(r, &cl);
1005
1006 if (ShenandoahPacing) {
1007 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1008 }
1009
1010 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
1011 break;
1012 }
1013 }
1014 }
1015 };
1016
1017 void ShenandoahHeap::trash_cset_regions() {
1018 ShenandoahHeapLocker locker(lock());
1019
1020 ShenandoahCollectionSet* set = collection_set();
1021 ShenandoahHeapRegion* r;
1022 set->clear_current_index();
1023 while ((r = set->next()) != NULL) {
1024 r->make_trash();
1025 }
1026 collection_set()->clear();
1027 }
1028
1029 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1030 st->print_cr("Heap Regions:");
1031 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1032 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1033 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1034 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1035
1036 for (size_t i = 0; i < num_regions(); i++) {
1037 get_region(i)->print_on(st);
1038 }
1039 }
1040
1041 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1042 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1043
1044 oop humongous_obj = oop(start->bottom() + ShenandoahForwarding::word_size());
1045 size_t size = humongous_obj->size() + ShenandoahForwarding::word_size();
1046 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1047 size_t index = start->region_number() + required_regions - 1;
1048
1049 assert(!start->has_live(), "liveness must be zero");
1050
1051 for(size_t i = 0; i < required_regions; i++) {
1052 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1053 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1054 ShenandoahHeapRegion* region = get_region(index --);
1055
1056 assert(region->is_humongous(), "expect correct humongous start or continuation");
1057 assert(!region->is_cset(), "Humongous region should not be in collection set");
1058
1059 region->make_trash_immediate();
1060 }
1061 }
1062
1063 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1064 public:
1065 void do_thread(Thread* thread) {
1066 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1067 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1068 gclab->retire();
1069 }
1070 };
1071
1072 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1073 if (UseTLAB) {
1074 CollectedHeap::ensure_parsability(retire_tlabs);
1075 }
1076 ShenandoahRetireGCLABClosure cl;
1077 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1078 cl.do_thread(t);
1079 }
1080 workers()->threads_do(&cl);
1081 }
1082
1083 void ShenandoahHeap::resize_tlabs() {
1084 CollectedHeap::resize_all_tlabs();
1085 }
1086
1087 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1088 private:
1089 ShenandoahRootEvacuator* _rp;
1090
1091 public:
1092 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1093 AbstractGangTask("Shenandoah evacuate and update roots"),
1094 _rp(rp) {}
1095
1096 void work(uint worker_id) {
1097 ShenandoahParallelWorkerSession worker_session(worker_id);
1098 ShenandoahEvacOOMScope oom_evac_scope;
1099 ShenandoahEvacuateUpdateRootsClosure cl;
1100 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1101 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1102 }
1103 };
1104
1105 void ShenandoahHeap::evacuate_and_update_roots() {
1106 #if defined(COMPILER2) || INCLUDE_JVMCI
1107 DerivedPointerTable::clear();
1108 #endif
1109 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1110
1111 {
1112 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1113 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1114 workers()->run_task(&roots_task);
1115 }
1116
1117 #if defined(COMPILER2) || INCLUDE_JVMCI
1118 DerivedPointerTable::update_pointers();
1119 #endif
1120 }
1121
1122 // Returns size in bytes
1123 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1124 if (ShenandoahElasticTLAB) {
1125 // With Elastic TLABs, return the max allowed size, and let the allocation path
1126 // figure out the safe size for current allocation.
1127 return ShenandoahHeapRegion::max_tlab_size_bytes();
1128 } else {
1129 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1130 }
1131 }
1132
1133 size_t ShenandoahHeap::max_tlab_size() const {
1134 // Returns size in words
1135 return ShenandoahHeapRegion::max_tlab_size_words();
1136 }
1137
1138 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1139 public:
1140 void do_thread(Thread* thread) {
1141 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1142 gclab->retire();
1143 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1144 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1145 }
1146 }
1147 };
1148
1149 void ShenandoahHeap::retire_and_reset_gclabs() {
1150 ShenandoahRetireAndResetGCLABClosure cl;
1151 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1152 cl.do_thread(t);
1153 }
1154 workers()->threads_do(&cl);
1155 }
1156
1157 void ShenandoahHeap::collect(GCCause::Cause cause) {
1158 control_thread()->request_gc(cause);
1159 }
1160
1161 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1162 //assert(false, "Shouldn't need to do full collections");
1163 }
1164
1165 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1166 Space* sp = heap_region_containing(addr);
1167 if (sp != NULL) {
1168 return sp->block_start(addr);
1169 }
1170 return NULL;
1171 }
1172
1173 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1174 Space* sp = heap_region_containing(addr);
1175 return sp->block_is_obj(addr);
1176 }
1177
1178 jlong ShenandoahHeap::millis_since_last_gc() {
1179 double v = heuristics()->time_since_last_gc() * 1000;
1180 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1181 return (jlong)v;
1182 }
1183
1184 void ShenandoahHeap::prepare_for_verify() {
1185 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1186 make_parsable(false);
1187 }
1188 }
1189
1190 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1191 workers()->print_worker_threads_on(st);
1192 if (ShenandoahStringDedup::is_enabled()) {
1193 ShenandoahStringDedup::print_worker_threads_on(st);
1194 }
1195 }
1196
1197 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1198 workers()->threads_do(tcl);
1199 if (_safepoint_workers != NULL) {
1200 _safepoint_workers->threads_do(tcl);
1201 }
1202 if (ShenandoahStringDedup::is_enabled()) {
1203 ShenandoahStringDedup::threads_do(tcl);
1204 }
1205 }
1206
1207 void ShenandoahHeap::print_tracing_info() const {
1208 LogTarget(Info, gc, stats) lt;
1209 if (lt.is_enabled()) {
1210 ResourceMark rm;
1211 LogStream ls(lt);
1212
1213 phase_timings()->print_on(&ls);
1214
1215 ls.cr();
1216 ls.cr();
1217
1218 shenandoah_policy()->print_gc_stats(&ls);
1219
1220 ls.cr();
1221 ls.cr();
1222
1223 if (ShenandoahPacing) {
1224 pacer()->print_on(&ls);
1225 }
1226
1227 ls.cr();
1228 ls.cr();
1229
1230 if (ShenandoahAllocationTrace) {
1231 assert(alloc_tracker() != NULL, "Must be");
1232 alloc_tracker()->print_on(&ls);
1233 } else {
1234 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1235 }
1236 }
1237 }
1238
1239 void ShenandoahHeap::verify(VerifyOption vo) {
1240 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1241 if (ShenandoahVerify) {
1242 verifier()->verify_generic(vo);
1243 } else {
1244 // TODO: Consider allocating verification bitmaps on demand,
1245 // and turn this on unconditionally.
1246 }
1247 }
1248 }
1249 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1250 return _free_set->capacity();
1251 }
1252
1253 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1254 private:
1255 MarkBitMap* _bitmap;
1256 Stack<oop,mtGC>* _oop_stack;
1257
1258 template <class T>
1259 void do_oop_work(T* p) {
1260 T o = RawAccess<>::oop_load(p);
1261 if (!CompressedOops::is_null(o)) {
1262 oop obj = CompressedOops::decode_not_null(o);
1263 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1264 assert(oopDesc::is_oop(obj), "must be a valid oop");
1265 if (!_bitmap->is_marked((HeapWord*) obj)) {
1266 _bitmap->mark((HeapWord*) obj);
1267 _oop_stack->push(obj);
1268 }
1269 }
1270 }
1271 public:
1272 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1273 _bitmap(bitmap), _oop_stack(oop_stack) {}
1274 void do_oop(oop* p) { do_oop_work(p); }
1275 void do_oop(narrowOop* p) { do_oop_work(p); }
1276 };
1277
1278 /*
1279 * This is public API, used in preparation of object_iterate().
1280 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1281 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1282 * control, we call SH::make_tlabs_parsable().
1283 */
1284 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1285 // No-op.
1286 }
1287
1288 /*
1289 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1290 *
1291 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1292 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1293 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1294 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1295 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1296 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1297 * wiped the bitmap in preparation for next marking).
1298 *
1299 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1300 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1301 * is allowed to report dead objects, but is not required to do so.
1302 */
1303 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1304 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1305 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1306 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1307 return;
1308 }
1309
1310 // Reset bitmap
1311 _aux_bit_map.clear();
1312
1313 Stack<oop,mtGC> oop_stack;
1314
1315 // First, we process all GC roots. This populates the work stack with initial objects.
1316 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1317 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1318 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1319 CodeBlobToOopClosure blobs(&oops, false);
1320 rp.process_all_roots(&oops, &clds, &blobs, NULL, 0);
1321
1322 // Work through the oop stack to traverse heap.
1323 while (! oop_stack.is_empty()) {
1324 oop obj = oop_stack.pop();
1325 assert(oopDesc::is_oop(obj), "must be a valid oop");
1326 cl->do_object(obj);
1327 obj->oop_iterate(&oops);
1328 }
1329
1330 assert(oop_stack.is_empty(), "should be empty");
1331
1332 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1333 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1334 }
1335 }
1336
1337 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1338 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1339 object_iterate(cl);
1340 }
1341
1342 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1343 for (size_t i = 0; i < num_regions(); i++) {
1344 ShenandoahHeapRegion* current = get_region(i);
1345 blk->heap_region_do(current);
1346 }
1347 }
1348
1349 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1350 private:
1351 ShenandoahHeap* const _heap;
1352 ShenandoahHeapRegionClosure* const _blk;
1353
1354 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1355 volatile size_t _index;
1356 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1357
1358 public:
1359 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1360 AbstractGangTask("Parallel Region Task"),
1361 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1362
1363 void work(uint worker_id) {
1364 size_t stride = ShenandoahParallelRegionStride;
1365
1366 size_t max = _heap->num_regions();
1367 while (_index < max) {
1368 size_t cur = Atomic::add(stride, &_index) - stride;
1369 size_t start = cur;
1370 size_t end = MIN2(cur + stride, max);
1371 if (start >= max) break;
1372
1373 for (size_t i = cur; i < end; i++) {
1374 ShenandoahHeapRegion* current = _heap->get_region(i);
1375 _blk->heap_region_do(current);
1376 }
1377 }
1378 }
1379 };
1380
1381 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1382 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1383 if (num_regions() > ShenandoahParallelRegionStride) {
1384 ShenandoahParallelHeapRegionTask task(blk);
1385 workers()->run_task(&task);
1386 } else {
1387 heap_region_iterate(blk);
1388 }
1389 }
1390
1391 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1392 private:
1393 ShenandoahMarkingContext* const _ctx;
1394 public:
1395 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1396
1397 void heap_region_do(ShenandoahHeapRegion* r) {
1398 if (r->is_active()) {
1399 r->clear_live_data();
1400 _ctx->capture_top_at_mark_start(r);
1401 } else {
1402 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1403 assert(_ctx->top_at_mark_start(r) == r->top(),
1404 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1405 }
1406 }
1407
1408 bool is_thread_safe() { return true; }
1409 };
1410
1411 void ShenandoahHeap::op_init_mark() {
1412 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1413 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1414
1415 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1416 assert(!marking_context()->is_complete(), "should not be complete");
1417
1418 if (ShenandoahVerify) {
1419 verifier()->verify_before_concmark();
1420 }
1421
1422 if (VerifyBeforeGC) {
1423 Universe::verify();
1424 }
1425
1426 set_concurrent_mark_in_progress(true);
1427 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1428 {
1429 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1430 make_parsable(true);
1431 }
1432
1433 {
1434 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1435 ShenandoahClearLivenessClosure clc;
1436 parallel_heap_region_iterate(&clc);
1437 }
1438
1439 // Make above changes visible to worker threads
1440 OrderAccess::fence();
1441
1442 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1443
1444 if (UseTLAB) {
1445 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1446 resize_tlabs();
1447 }
1448
1449 if (ShenandoahPacing) {
1450 pacer()->setup_for_mark();
1451 }
1452 }
1453
1454 void ShenandoahHeap::op_mark() {
1455 concurrent_mark()->mark_from_roots();
1456 }
1457
1458 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1459 private:
1460 ShenandoahMarkingContext* const _ctx;
1461 public:
1462 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1463
1464 void heap_region_do(ShenandoahHeapRegion* r) {
1465 if (r->is_active()) {
1466 HeapWord *tams = _ctx->top_at_mark_start(r);
1467 HeapWord *top = r->top();
1468 if (top > tams) {
1469 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1470 }
1471 } else {
1472 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1473 assert(_ctx->top_at_mark_start(r) == r->top(),
1474 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1475 }
1476 }
1477
1478 bool is_thread_safe() { return true; }
1479 };
1480
1481 void ShenandoahHeap::op_final_mark() {
1482 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1483
1484 // It is critical that we
1485 // evacuate roots right after finishing marking, so that we don't
1486 // get unmarked objects in the roots.
1487
1488 if (!cancelled_gc()) {
1489 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1490
1491 // Degen may be caused by failed evacuation of roots
1492 if (is_degenerated_gc_in_progress() && has_forwarded_objects()) {
1493 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
1494 }
1495
1496 if (ShenandoahVerify) {
1497 verifier()->verify_roots_no_forwarded();
1498 }
1499
1500 stop_concurrent_marking();
1501
1502 {
1503 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1504
1505 // All allocations past TAMS are implicitly live, adjust the region data.
1506 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1507 ShenandoahCompleteLivenessClosure cl;
1508 parallel_heap_region_iterate(&cl);
1509 }
1510
1511 {
1512 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1513
1514 make_parsable(true);
1515
1516 trash_cset_regions();
1517
1518 {
1519 ShenandoahHeapLocker locker(lock());
1520 _collection_set->clear();
1521 _free_set->clear();
1522
1523 heuristics()->choose_collection_set(_collection_set);
1524
1525 _free_set->rebuild();
1526 }
1527 }
1528
1529 // If collection set has candidates, start evacuation.
1530 // Otherwise, bypass the rest of the cycle.
1531 if (!collection_set()->is_empty()) {
1532 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1533
1534 if (ShenandoahVerify) {
1535 verifier()->verify_before_evacuation();
1536 }
1537
1538 set_evacuation_in_progress(true);
1539 // From here on, we need to update references.
1540 set_has_forwarded_objects(true);
1541
1542 evacuate_and_update_roots();
1543
1544 if (ShenandoahPacing) {
1545 pacer()->setup_for_evac();
1546 }
1547
1548 if (ShenandoahVerify) {
1549 verifier()->verify_roots_no_forwarded();
1550 verifier()->verify_during_evacuation();
1551 }
1552 } else {
1553 if (ShenandoahVerify) {
1554 verifier()->verify_after_concmark();
1555 }
1556
1557 if (VerifyAfterGC) {
1558 Universe::verify();
1559 }
1560 }
1561
1562 } else {
1563 concurrent_mark()->cancel();
1564 stop_concurrent_marking();
1565
1566 if (process_references()) {
1567 // Abandon reference processing right away: pre-cleaning must have failed.
1568 ReferenceProcessor *rp = ref_processor();
1569 rp->disable_discovery();
1570 rp->abandon_partial_discovery();
1571 rp->verify_no_references_recorded();
1572 }
1573 }
1574 }
1575
1576 void ShenandoahHeap::op_final_evac() {
1577 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1578
1579 set_evacuation_in_progress(false);
1580
1581 retire_and_reset_gclabs();
1582
1583 if (ShenandoahVerify) {
1584 verifier()->verify_after_evacuation();
1585 }
1586
1587 if (VerifyAfterGC) {
1588 Universe::verify();
1589 }
1590 }
1591
1592 void ShenandoahHeap::op_conc_evac() {
1593 ShenandoahEvacuationTask task(this, _collection_set, true);
1594 workers()->run_task(&task);
1595 }
1596
1597 void ShenandoahHeap::op_stw_evac() {
1598 ShenandoahEvacuationTask task(this, _collection_set, false);
1599 workers()->run_task(&task);
1600 }
1601
1602 void ShenandoahHeap::op_updaterefs() {
1603 update_heap_references(true);
1604 }
1605
1606 void ShenandoahHeap::op_cleanup() {
1607 free_set()->recycle_trash();
1608 }
1609
1610 void ShenandoahHeap::op_reset() {
1611 reset_mark_bitmap();
1612 }
1613
1614 void ShenandoahHeap::op_preclean() {
1615 concurrent_mark()->preclean_weak_refs();
1616 }
1617
1618 void ShenandoahHeap::op_init_traversal() {
1619 traversal_gc()->init_traversal_collection();
1620 }
1621
1622 void ShenandoahHeap::op_traversal() {
1623 traversal_gc()->concurrent_traversal_collection();
1624 }
1625
1626 void ShenandoahHeap::op_final_traversal() {
1627 traversal_gc()->final_traversal_collection();
1628 }
1629
1630 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1631 ShenandoahMetricsSnapshot metrics;
1632 metrics.snap_before();
1633
1634 full_gc()->do_it(cause);
1635 if (UseTLAB) {
1636 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1637 resize_all_tlabs();
1638 }
1639
1640 metrics.snap_after();
1641 metrics.print();
1642
1643 if (metrics.is_good_progress("Full GC")) {
1644 _progress_last_gc.set();
1645 } else {
1646 // Nothing to do. Tell the allocation path that we have failed to make
1647 // progress, and it can finally fail.
1648 _progress_last_gc.unset();
1649 }
1650 }
1651
1652 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1653 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1654 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1655 // some phase, we have to upgrade the Degenerate GC to Full GC.
1656
1657 clear_cancelled_gc();
1658
1659 ShenandoahMetricsSnapshot metrics;
1660 metrics.snap_before();
1661
1662 switch (point) {
1663 case _degenerated_traversal:
1664 {
1665 // Drop the collection set. Note: this leaves some already forwarded objects
1666 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1667 // workarounds in ShenandoahTraversalHeuristics.
1668
1669 ShenandoahHeapLocker locker(lock());
1670 collection_set()->clear_current_index();
1671 for (size_t i = 0; i < collection_set()->count(); i++) {
1672 ShenandoahHeapRegion* r = collection_set()->next();
1673 r->make_regular_bypass();
1674 }
1675 collection_set()->clear();
1676 }
1677 op_final_traversal();
1678 op_cleanup();
1679 return;
1680
1681 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1682 // but enters it at different points, depending on which concurrent phase had
1683 // degenerated.
1684
1685 case _degenerated_outside_cycle:
1686 // We have degenerated from outside the cycle, which means something is bad with
1687 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1688 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1689 // we can do the most aggressive degen cycle, which includes processing references and
1690 // class unloading, unless those features are explicitly disabled.
1691 //
1692 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1693 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1694 set_process_references(heuristics()->can_process_references());
1695 set_unload_classes(heuristics()->can_unload_classes());
1696
1697 if (heuristics()->can_do_traversal_gc()) {
1698 // Not possible to degenerate from here, upgrade to Full GC right away.
1699 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1700 op_degenerated_fail();
1701 return;
1702 }
1703
1704 op_reset();
1705
1706 op_init_mark();
1707 if (cancelled_gc()) {
1708 op_degenerated_fail();
1709 return;
1710 }
1711
1712 case _degenerated_mark:
1713 op_final_mark();
1714 if (cancelled_gc()) {
1715 op_degenerated_fail();
1716 return;
1717 }
1718
1719 op_cleanup();
1720
1721 case _degenerated_evac:
1722 // If heuristics thinks we should do the cycle, this flag would be set,
1723 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1724 if (is_evacuation_in_progress()) {
1725
1726 // Degeneration under oom-evac protocol might have left some objects in
1727 // collection set un-evacuated. Restart evacuation from the beginning to
1728 // capture all objects. For all the objects that are already evacuated,
1729 // it would be a simple check, which is supposed to be fast. This is also
1730 // safe to do even without degeneration, as CSet iterator is at beginning
1731 // in preparation for evacuation anyway.
1732 collection_set()->clear_current_index();
1733
1734 op_stw_evac();
1735 if (cancelled_gc()) {
1736 op_degenerated_fail();
1737 return;
1738 }
1739 }
1740
1741 // If heuristics thinks we should do the cycle, this flag would be set,
1742 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1743 if (has_forwarded_objects()) {
1744 op_init_updaterefs();
1745 if (cancelled_gc()) {
1746 op_degenerated_fail();
1747 return;
1748 }
1749 }
1750
1751 case _degenerated_updaterefs:
1752 if (has_forwarded_objects()) {
1753 op_final_updaterefs();
1754 if (cancelled_gc()) {
1755 op_degenerated_fail();
1756 return;
1757 }
1758 }
1759
1760 op_cleanup();
1761 break;
1762
1763 default:
1764 ShouldNotReachHere();
1765 }
1766
1767 if (ShenandoahVerify) {
1768 verifier()->verify_after_degenerated();
1769 }
1770
1771 if (VerifyAfterGC) {
1772 Universe::verify();
1773 }
1774
1775 metrics.snap_after();
1776 metrics.print();
1777
1778 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1779 // because that probably means the heap is overloaded and/or fragmented.
1780 if (!metrics.is_good_progress("Degenerated GC")) {
1781 _progress_last_gc.unset();
1782 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1783 op_degenerated_futile();
1784 } else {
1785 _progress_last_gc.set();
1786 }
1787 }
1788
1789 void ShenandoahHeap::op_degenerated_fail() {
1790 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1791 shenandoah_policy()->record_degenerated_upgrade_to_full();
1792 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1793 }
1794
1795 void ShenandoahHeap::op_degenerated_futile() {
1796 shenandoah_policy()->record_degenerated_upgrade_to_full();
1797 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1798 }
1799
1800 void ShenandoahHeap::stop_concurrent_marking() {
1801 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1802 set_concurrent_mark_in_progress(false);
1803 if (!cancelled_gc()) {
1804 // If we needed to update refs, and concurrent marking has been cancelled,
1805 // we need to finish updating references.
1806 set_has_forwarded_objects(false);
1807 mark_complete_marking_context();
1808 }
1809 }
1810
1811 void ShenandoahHeap::force_satb_flush_all_threads() {
1812 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1813 // No need to flush SATBs
1814 return;
1815 }
1816
1817 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1818 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1819 }
1820 // The threads are not "acquiring" their thread-local data, but it does not
1821 // hurt to "release" the updates here anyway.
1822 OrderAccess::fence();
1823 }
1824
1825 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1826 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1827 ShenandoahThreadLocalData::set_gc_state(t, state);
1828 }
1829 }
1830
1831 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1832 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1833 _gc_state.set_cond(mask, value);
1834 set_gc_state_all_threads(_gc_state.raw_value());
1835 }
1836
1837 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1838 if (has_forwarded_objects()) {
1839 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
1840 } else {
1841 set_gc_state_mask(MARKING, in_progress);
1842 }
1843 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1844 }
1845
1846 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1847 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED | UPDATEREFS, in_progress);
1848 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1849 }
1850
1851 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1852 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1853 set_gc_state_mask(EVACUATION, in_progress);
1854 }
1855
1856 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1857 // Initialize Brooks pointer for the next object
1858 HeapWord* result = obj + ShenandoahForwarding::word_size();
1859 ShenandoahForwarding::initialize(oop(result));
1860 return result;
1861 }
1862
1863 void ShenandoahHeap::ref_processing_init() {
1864 assert(_max_workers > 0, "Sanity");
1865
1866 _ref_processor =
1867 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1868 ParallelRefProcEnabled, // MT processing
1869 _max_workers, // Degree of MT processing
1870 true, // MT discovery
1871 _max_workers, // Degree of MT discovery
1872 false, // Reference discovery is not atomic
1873 NULL, // No closure, should be installed before use
1874 true); // Scale worker threads
1875
1876 shenandoah_assert_rp_isalive_not_installed();
1877 }
1878
1879 GCTracer* ShenandoahHeap::tracer() {
1880 return shenandoah_policy()->tracer();
1881 }
1882
1883 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1884 return _free_set->used();
1885 }
1886
1887 bool ShenandoahHeap::try_cancel_gc() {
1888 while (true) {
1889 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1890 if (prev == CANCELLABLE) return true;
1891 else if (prev == CANCELLED) return false;
1892 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1893 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1894 {
1895 // We need to provide a safepoint here, otherwise we might
1896 // spin forever if a SP is pending.
1897 ThreadBlockInVM sp(JavaThread::current());
1898 SpinPause();
1899 }
1900 }
1901 }
1902
1903 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1904 if (try_cancel_gc()) {
1905 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1906 log_info(gc)("%s", msg.buffer());
1907 Events::log(Thread::current(), "%s", msg.buffer());
1908 }
1909 }
1910
1911 uint ShenandoahHeap::max_workers() {
1912 return _max_workers;
1913 }
1914
1915 void ShenandoahHeap::stop() {
1916 // The shutdown sequence should be able to terminate when GC is running.
1917
1918 // Step 0. Notify policy to disable event recording.
1919 _shenandoah_policy->record_shutdown();
1920
1921 // Step 1. Notify control thread that we are in shutdown.
1922 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1923 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1924 control_thread()->prepare_for_graceful_shutdown();
1925
1926 // Step 2. Notify GC workers that we are cancelling GC.
1927 cancel_gc(GCCause::_shenandoah_stop_vm);
1928
1929 // Step 3. Wait until GC worker exits normally.
1930 control_thread()->stop();
1931
1932 // Step 4. Stop String Dedup thread if it is active
1933 if (ShenandoahStringDedup::is_enabled()) {
1934 ShenandoahStringDedup::stop();
1935 }
1936 }
1937
1938 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1939 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1940
1941 ShenandoahGCPhase root_phase(full_gc ?
1942 ShenandoahPhaseTimings::full_gc_purge :
1943 ShenandoahPhaseTimings::purge);
1944
1945 ShenandoahIsAliveSelector alive;
1946 BoolObjectClosure* is_alive = alive.is_alive_closure();
1947
1948 bool purged_class;
1949
1950 // Unload classes and purge SystemDictionary.
1951 {
1952 ShenandoahGCPhase phase(full_gc ?
1953 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1954 ShenandoahPhaseTimings::purge_class_unload);
1955 purged_class = SystemDictionary::do_unloading(gc_timer());
1956 }
1957
1958 {
1959 ShenandoahGCPhase phase(full_gc ?
1960 ShenandoahPhaseTimings::full_gc_purge_par :
1961 ShenandoahPhaseTimings::purge_par);
1962 uint active = _workers->active_workers();
1963 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1964 _workers->run_task(&unlink_task);
1965 }
1966
1967 {
1968 ShenandoahGCPhase phase(full_gc ?
1969 ShenandoahPhaseTimings::full_gc_purge_cldg :
1970 ShenandoahPhaseTimings::purge_cldg);
1971 ClassLoaderDataGraph::purge();
1972 }
1973 }
1974
1975 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1976 set_gc_state_mask(HAS_FORWARDED, cond);
1977 }
1978
1979 void ShenandoahHeap::set_process_references(bool pr) {
1980 _process_references.set_cond(pr);
1981 }
1982
1983 void ShenandoahHeap::set_unload_classes(bool uc) {
1984 _unload_classes.set_cond(uc);
1985 }
1986
1987 bool ShenandoahHeap::process_references() const {
1988 return _process_references.is_set();
1989 }
1990
1991 bool ShenandoahHeap::unload_classes() const {
1992 return _unload_classes.is_set();
1993 }
1994
1995 address ShenandoahHeap::in_cset_fast_test_addr() {
1996 ShenandoahHeap* heap = ShenandoahHeap::heap();
1997 assert(heap->collection_set() != NULL, "Sanity");
1998 return (address) heap->collection_set()->biased_map_address();
1999 }
2000
2001 address ShenandoahHeap::cancelled_gc_addr() {
2002 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2003 }
2004
2005 address ShenandoahHeap::gc_state_addr() {
2006 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2007 }
2008
2009 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2010 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2011 }
2012
2013 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2014 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2015 }
2016
2017 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2018 _degenerated_gc_in_progress.set_cond(in_progress);
2019 }
2020
2021 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2022 _full_gc_in_progress.set_cond(in_progress);
2023 }
2024
2025 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2026 assert (is_full_gc_in_progress(), "should be");
2027 _full_gc_move_in_progress.set_cond(in_progress);
2028 }
2029
2030 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2031 set_gc_state_mask(UPDATEREFS, in_progress);
2032 }
2033
2034 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2035 ShenandoahCodeRoots::add_nmethod(nm);
2036 }
2037
2038 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2039 ShenandoahCodeRoots::remove_nmethod(nm);
2040 }
2041
2042 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2043 ShenandoahHeapLocker locker(lock());
2044 heap_region_containing(o)->make_pinned();
2045 return o;
2046 }
2047
2048 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2049 ShenandoahHeapLocker locker(lock());
2050 heap_region_containing(o)->make_unpinned();
2051 }
2052
2053 GCTimer* ShenandoahHeap::gc_timer() const {
2054 return _gc_timer;
2055 }
2056
2057 #ifdef ASSERT
2058 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2059 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2060
2061 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2062 if (UseDynamicNumberOfGCThreads ||
2063 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2064 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2065 } else {
2066 // Use ParallelGCThreads inside safepoints
2067 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2068 }
2069 } else {
2070 if (UseDynamicNumberOfGCThreads ||
2071 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2072 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2073 } else {
2074 // Use ConcGCThreads outside safepoints
2075 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2076 }
2077 }
2078 }
2079 #endif
2080
2081 ShenandoahVerifier* ShenandoahHeap::verifier() {
2082 guarantee(ShenandoahVerify, "Should be enabled");
2083 assert (_verifier != NULL, "sanity");
2084 return _verifier;
2085 }
2086
2087 template<class T>
2088 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2089 private:
2090 T cl;
2091 ShenandoahHeap* _heap;
2092 ShenandoahRegionIterator* _regions;
2093 bool _concurrent;
2094 public:
2095 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2096 AbstractGangTask("Concurrent Update References Task"),
2097 cl(T()),
2098 _heap(ShenandoahHeap::heap()),
2099 _regions(regions),
2100 _concurrent(concurrent) {
2101 }
2102
2103 void work(uint worker_id) {
2104 if (_concurrent) {
2105 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2106 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2107 do_work();
2108 } else {
2109 ShenandoahParallelWorkerSession worker_session(worker_id);
2110 do_work();
2111 }
2112 }
2113
2114 private:
2115 void do_work() {
2116 ShenandoahHeapRegion* r = _regions->next();
2117 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2118 while (r != NULL) {
2119 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2120 assert (top_at_start_ur >= r->bottom(), "sanity");
2121 if (r->is_active() && !r->is_cset()) {
2122 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2123 }
2124 if (ShenandoahPacing) {
2125 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2126 }
2127 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2128 return;
2129 }
2130 r = _regions->next();
2131 }
2132 }
2133 };
2134
2135 void ShenandoahHeap::update_heap_references(bool concurrent) {
2136 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2137 workers()->run_task(&task);
2138 }
2139
2140 void ShenandoahHeap::op_init_updaterefs() {
2141 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2142
2143 set_evacuation_in_progress(false);
2144
2145 retire_and_reset_gclabs();
2146
2147 if (ShenandoahVerify) {
2148 verifier()->verify_before_updaterefs();
2149 }
2150
2151 set_update_refs_in_progress(true);
2152 make_parsable(true);
2153 for (uint i = 0; i < num_regions(); i++) {
2154 ShenandoahHeapRegion* r = get_region(i);
2155 r->set_concurrent_iteration_safe_limit(r->top());
2156 }
2157
2158 // Reset iterator.
2159 _update_refs_iterator.reset();
2160
2161 if (ShenandoahPacing) {
2162 pacer()->setup_for_updaterefs();
2163 }
2164 }
2165
2166 void ShenandoahHeap::op_final_updaterefs() {
2167 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2168
2169 // Check if there is left-over work, and finish it
2170 if (_update_refs_iterator.has_next()) {
2171 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2172
2173 // Finish updating references where we left off.
2174 clear_cancelled_gc();
2175 update_heap_references(false);
2176 }
2177
2178 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2179 // everything. On degenerated paths, cancelled gc would not be set anyway.
2180 if (cancelled_gc()) {
2181 clear_cancelled_gc();
2182 }
2183 assert(!cancelled_gc(), "Should have been done right before");
2184
2185 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2186 ShenandoahPhaseTimings::degen_gc_update_roots:
2187 ShenandoahPhaseTimings::final_update_refs_roots);
2188
2189 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2190
2191 trash_cset_regions();
2192 set_has_forwarded_objects(false);
2193 set_update_refs_in_progress(false);
2194
2195 if (ShenandoahVerify) {
2196 verifier()->verify_roots_no_forwarded();
2197 verifier()->verify_after_updaterefs();
2198 }
2199
2200 if (VerifyAfterGC) {
2201 Universe::verify();
2202 }
2203
2204 {
2205 ShenandoahHeapLocker locker(lock());
2206 _free_set->rebuild();
2207 }
2208 }
2209
2210 #ifdef ASSERT
2211 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2212 _lock.assert_owned_by_current_thread();
2213 }
2214
2215 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2216 _lock.assert_not_owned_by_current_thread();
2217 }
2218
2219 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2220 _lock.assert_owned_by_current_thread_or_safepoint();
2221 }
2222 #endif
2223
2224 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2225 print_on(st);
2226 print_heap_regions_on(st);
2227 }
2228
2229 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2230 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2231
2232 size_t regions_from = _bitmap_regions_per_slice * slice;
2233 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2234 for (size_t g = regions_from; g < regions_to; g++) {
2235 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2236 if (skip_self && g == r->region_number()) continue;
2237 if (get_region(g)->is_committed()) {
2238 return true;
2239 }
2240 }
2241 return false;
2242 }
2243
2244 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2245 assert_heaplock_owned_by_current_thread();
2246
2247 // Bitmaps in special regions do not need commits
2248 if (_bitmap_region_special) {
2249 return true;
2250 }
2251
2252 if (is_bitmap_slice_committed(r, true)) {
2253 // Some other region from the group is already committed, meaning the bitmap
2254 // slice is already committed, we exit right away.
2255 return true;
2256 }
2257
2258 // Commit the bitmap slice:
2259 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2260 size_t off = _bitmap_bytes_per_slice * slice;
2261 size_t len = _bitmap_bytes_per_slice;
2262 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2263 return false;
2264 }
2265 return true;
2266 }
2267
2268 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2269 assert_heaplock_owned_by_current_thread();
2270
2271 // Bitmaps in special regions do not need uncommits
2272 if (_bitmap_region_special) {
2273 return true;
2274 }
2275
2276 if (is_bitmap_slice_committed(r, true)) {
2277 // Some other region from the group is still committed, meaning the bitmap
2278 // slice is should stay committed, exit right away.
2279 return true;
2280 }
2281
2282 // Uncommit the bitmap slice:
2283 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2284 size_t off = _bitmap_bytes_per_slice * slice;
2285 size_t len = _bitmap_bytes_per_slice;
2286 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2287 return false;
2288 }
2289 return true;
2290 }
2291
2292 void ShenandoahHeap::safepoint_synchronize_begin() {
2293 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2294 SuspendibleThreadSet::synchronize();
2295 }
2296 }
2297
2298 void ShenandoahHeap::safepoint_synchronize_end() {
2299 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2300 SuspendibleThreadSet::desynchronize();
2301 }
2302 }
2303
2304 void ShenandoahHeap::vmop_entry_init_mark() {
2305 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2306 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2307 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2308
2309 try_inject_alloc_failure();
2310 VM_ShenandoahInitMark op;
2311 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2312 }
2313
2314 void ShenandoahHeap::vmop_entry_final_mark() {
2315 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2316 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2317 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2318
2319 try_inject_alloc_failure();
2320 VM_ShenandoahFinalMarkStartEvac op;
2321 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2322 }
2323
2324 void ShenandoahHeap::vmop_entry_final_evac() {
2325 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2326 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2327 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2328
2329 VM_ShenandoahFinalEvac op;
2330 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2331 }
2332
2333 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2334 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2335 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2336 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2337
2338 try_inject_alloc_failure();
2339 VM_ShenandoahInitUpdateRefs op;
2340 VMThread::execute(&op);
2341 }
2342
2343 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2344 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2345 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2346 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2347
2348 try_inject_alloc_failure();
2349 VM_ShenandoahFinalUpdateRefs op;
2350 VMThread::execute(&op);
2351 }
2352
2353 void ShenandoahHeap::vmop_entry_init_traversal() {
2354 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2355 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2356 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2357
2358 try_inject_alloc_failure();
2359 VM_ShenandoahInitTraversalGC op;
2360 VMThread::execute(&op);
2361 }
2362
2363 void ShenandoahHeap::vmop_entry_final_traversal() {
2364 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2365 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2366 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2367
2368 try_inject_alloc_failure();
2369 VM_ShenandoahFinalTraversalGC op;
2370 VMThread::execute(&op);
2371 }
2372
2373 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2374 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2375 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2376 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2377
2378 try_inject_alloc_failure();
2379 VM_ShenandoahFullGC op(cause);
2380 VMThread::execute(&op);
2381 }
2382
2383 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2384 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2385 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2386 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2387
2388 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2389 VMThread::execute(°enerated_gc);
2390 }
2391
2392 void ShenandoahHeap::entry_init_mark() {
2393 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2394 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2395 const char* msg = init_mark_event_message();
2396 GCTraceTime(Info, gc) time(msg, gc_timer());
2397 EventMark em("%s", msg);
2398
2399 ShenandoahWorkerScope scope(workers(),
2400 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2401 "init marking");
2402
2403 op_init_mark();
2404 }
2405
2406 void ShenandoahHeap::entry_final_mark() {
2407 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2408 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2409 const char* msg = final_mark_event_message();
2410 GCTraceTime(Info, gc) time(msg, gc_timer());
2411 EventMark em("%s", msg);
2412
2413 ShenandoahWorkerScope scope(workers(),
2414 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2415 "final marking");
2416
2417 op_final_mark();
2418 }
2419
2420 void ShenandoahHeap::entry_final_evac() {
2421 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2422 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2423 static const char* msg = "Pause Final Evac";
2424 GCTraceTime(Info, gc) time(msg, gc_timer());
2425 EventMark em("%s", msg);
2426
2427 op_final_evac();
2428 }
2429
2430 void ShenandoahHeap::entry_init_updaterefs() {
2431 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2432 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2433
2434 static const char* msg = "Pause Init Update Refs";
2435 GCTraceTime(Info, gc) time(msg, gc_timer());
2436 EventMark em("%s", msg);
2437
2438 // No workers used in this phase, no setup required
2439
2440 op_init_updaterefs();
2441 }
2442
2443 void ShenandoahHeap::entry_final_updaterefs() {
2444 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2445 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2446
2447 static const char* msg = "Pause Final Update Refs";
2448 GCTraceTime(Info, gc) time(msg, gc_timer());
2449 EventMark em("%s", msg);
2450
2451 ShenandoahWorkerScope scope(workers(),
2452 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2453 "final reference update");
2454
2455 op_final_updaterefs();
2456 }
2457
2458 void ShenandoahHeap::entry_init_traversal() {
2459 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2460 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2461
2462 static const char* msg = "Pause Init Traversal";
2463 GCTraceTime(Info, gc) time(msg, gc_timer());
2464 EventMark em("%s", msg);
2465
2466 ShenandoahWorkerScope scope(workers(),
2467 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2468 "init traversal");
2469
2470 op_init_traversal();
2471 }
2472
2473 void ShenandoahHeap::entry_final_traversal() {
2474 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2475 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2476
2477 static const char* msg = "Pause Final Traversal";
2478 GCTraceTime(Info, gc) time(msg, gc_timer());
2479 EventMark em("%s", msg);
2480
2481 ShenandoahWorkerScope scope(workers(),
2482 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2483 "final traversal");
2484
2485 op_final_traversal();
2486 }
2487
2488 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2489 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2490 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2491
2492 static const char* msg = "Pause Full";
2493 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2494 EventMark em("%s", msg);
2495
2496 ShenandoahWorkerScope scope(workers(),
2497 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2498 "full gc");
2499
2500 op_full(cause);
2501 }
2502
2503 void ShenandoahHeap::entry_degenerated(int point) {
2504 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2505 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2506
2507 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2508 const char* msg = degen_event_message(dpoint);
2509 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2510 EventMark em("%s", msg);
2511
2512 ShenandoahWorkerScope scope(workers(),
2513 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2514 "stw degenerated gc");
2515
2516 set_degenerated_gc_in_progress(true);
2517 op_degenerated(dpoint);
2518 set_degenerated_gc_in_progress(false);
2519 }
2520
2521 void ShenandoahHeap::entry_mark() {
2522 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2523
2524 const char* msg = conc_mark_event_message();
2525 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2526 EventMark em("%s", msg);
2527
2528 ShenandoahWorkerScope scope(workers(),
2529 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2530 "concurrent marking");
2531
2532 try_inject_alloc_failure();
2533 op_mark();
2534 }
2535
2536 void ShenandoahHeap::entry_evac() {
2537 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2538 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2539
2540 static const char* msg = "Concurrent evacuation";
2541 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2542 EventMark em("%s", msg);
2543
2544 ShenandoahWorkerScope scope(workers(),
2545 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2546 "concurrent evacuation");
2547
2548 try_inject_alloc_failure();
2549 op_conc_evac();
2550 }
2551
2552 void ShenandoahHeap::entry_updaterefs() {
2553 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2554
2555 static const char* msg = "Concurrent update references";
2556 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2557 EventMark em("%s", msg);
2558
2559 ShenandoahWorkerScope scope(workers(),
2560 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2561 "concurrent reference update");
2562
2563 try_inject_alloc_failure();
2564 op_updaterefs();
2565 }
2566 void ShenandoahHeap::entry_cleanup() {
2567 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2568
2569 static const char* msg = "Concurrent cleanup";
2570 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2571 EventMark em("%s", msg);
2572
2573 // This phase does not use workers, no need for setup
2574
2575 try_inject_alloc_failure();
2576 op_cleanup();
2577 }
2578
2579 void ShenandoahHeap::entry_reset() {
2580 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2581
2582 static const char* msg = "Concurrent reset";
2583 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2584 EventMark em("%s", msg);
2585
2586 ShenandoahWorkerScope scope(workers(),
2587 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2588 "concurrent reset");
2589
2590 try_inject_alloc_failure();
2591 op_reset();
2592 }
2593
2594 void ShenandoahHeap::entry_preclean() {
2595 if (ShenandoahPreclean && process_references()) {
2596 static const char* msg = "Concurrent precleaning";
2597 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2598 EventMark em("%s", msg);
2599
2600 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2601
2602 ShenandoahWorkerScope scope(workers(),
2603 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2604 "concurrent preclean",
2605 /* check_workers = */ false);
2606
2607 try_inject_alloc_failure();
2608 op_preclean();
2609 }
2610 }
2611
2612 void ShenandoahHeap::entry_traversal() {
2613 static const char* msg = "Concurrent traversal";
2614 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2615 EventMark em("%s", msg);
2616
2617 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2618
2619 ShenandoahWorkerScope scope(workers(),
2620 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2621 "concurrent traversal");
2622
2623 try_inject_alloc_failure();
2624 op_traversal();
2625 }
2626
2627 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2628 static const char *msg = "Concurrent uncommit";
2629 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2630 EventMark em("%s", msg);
2631
2632 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2633
2634 op_uncommit(shrink_before);
2635 }
2636
2637 void ShenandoahHeap::try_inject_alloc_failure() {
2638 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2639 _inject_alloc_failure.set();
2640 os::naked_short_sleep(1);
2641 if (cancelled_gc()) {
2642 log_info(gc)("Allocation failure was successfully injected");
2643 }
2644 }
2645 }
2646
2647 bool ShenandoahHeap::should_inject_alloc_failure() {
2648 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2649 }
2650
2651 void ShenandoahHeap::initialize_serviceability() {
2652 _memory_pool = new ShenandoahMemoryPool(this);
2653 _cycle_memory_manager.add_pool(_memory_pool);
2654 _stw_memory_manager.add_pool(_memory_pool);
2655 }
2656
2657 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2658 GrowableArray<GCMemoryManager*> memory_managers(2);
2659 memory_managers.append(&_cycle_memory_manager);
2660 memory_managers.append(&_stw_memory_manager);
2661 return memory_managers;
2662 }
2663
2664 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2665 GrowableArray<MemoryPool*> memory_pools(1);
2666 memory_pools.append(_memory_pool);
2667 return memory_pools;
2668 }
2669
2670 MemoryUsage ShenandoahHeap::memory_usage() {
2671 return _memory_pool->get_memory_usage();
2672 }
2673
2674 void ShenandoahHeap::enter_evacuation() {
2675 _oom_evac_handler.enter_evacuation();
2676 }
2677
2678 void ShenandoahHeap::leave_evacuation() {
2679 _oom_evac_handler.leave_evacuation();
2680 }
2681
2682 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2683 _heap(ShenandoahHeap::heap()),
2684 _index(0) {}
2685
2686 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2687 _heap(heap),
2688 _index(0) {}
2689
2690 void ShenandoahRegionIterator::reset() {
2691 _index = 0;
2692 }
2693
2694 bool ShenandoahRegionIterator::has_next() const {
2695 return _index < _heap->num_regions();
2696 }
2697
2698 char ShenandoahHeap::gc_state() const {
2699 return _gc_state.raw_value();
2700 }
2701
2702 void ShenandoahHeap::deduplicate_string(oop str) {
2703 assert(java_lang_String::is_instance(str), "invariant");
2704
2705 if (ShenandoahStringDedup::is_enabled()) {
2706 ShenandoahStringDedup::deduplicate(str);
2707 }
2708 }
2709
2710 const char* ShenandoahHeap::init_mark_event_message() const {
2711 bool update_refs = has_forwarded_objects();
2712 bool proc_refs = process_references();
2713 bool unload_cls = unload_classes();
2714
2715 if (update_refs && proc_refs && unload_cls) {
2716 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2717 } else if (update_refs && proc_refs) {
2718 return "Pause Init Mark (update refs) (process weakrefs)";
2719 } else if (update_refs && unload_cls) {
2720 return "Pause Init Mark (update refs) (unload classes)";
2721 } else if (proc_refs && unload_cls) {
2722 return "Pause Init Mark (process weakrefs) (unload classes)";
2723 } else if (update_refs) {
2724 return "Pause Init Mark (update refs)";
2725 } else if (proc_refs) {
2726 return "Pause Init Mark (process weakrefs)";
2727 } else if (unload_cls) {
2728 return "Pause Init Mark (unload classes)";
2729 } else {
2730 return "Pause Init Mark";
2731 }
2732 }
2733
2734 const char* ShenandoahHeap::final_mark_event_message() const {
2735 bool update_refs = has_forwarded_objects();
2736 bool proc_refs = process_references();
2737 bool unload_cls = unload_classes();
2738
2739 if (update_refs && proc_refs && unload_cls) {
2740 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2741 } else if (update_refs && proc_refs) {
2742 return "Pause Final Mark (update refs) (process weakrefs)";
2743 } else if (update_refs && unload_cls) {
2744 return "Pause Final Mark (update refs) (unload classes)";
2745 } else if (proc_refs && unload_cls) {
2746 return "Pause Final Mark (process weakrefs) (unload classes)";
2747 } else if (update_refs) {
2748 return "Pause Final Mark (update refs)";
2749 } else if (proc_refs) {
2750 return "Pause Final Mark (process weakrefs)";
2751 } else if (unload_cls) {
2752 return "Pause Final Mark (unload classes)";
2753 } else {
2754 return "Pause Final Mark";
2755 }
2756 }
2757
2758 const char* ShenandoahHeap::conc_mark_event_message() const {
2759 bool update_refs = has_forwarded_objects();
2760 bool proc_refs = process_references();
2761 bool unload_cls = unload_classes();
2762
2763 if (update_refs && proc_refs && unload_cls) {
2764 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2765 } else if (update_refs && proc_refs) {
2766 return "Concurrent marking (update refs) (process weakrefs)";
2767 } else if (update_refs && unload_cls) {
2768 return "Concurrent marking (update refs) (unload classes)";
2769 } else if (proc_refs && unload_cls) {
2770 return "Concurrent marking (process weakrefs) (unload classes)";
2771 } else if (update_refs) {
2772 return "Concurrent marking (update refs)";
2773 } else if (proc_refs) {
2774 return "Concurrent marking (process weakrefs)";
2775 } else if (unload_cls) {
2776 return "Concurrent marking (unload classes)";
2777 } else {
2778 return "Concurrent marking";
2779 }
2780 }
2781
2782 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2783 switch (point) {
2784 case _degenerated_unset:
2785 return "Pause Degenerated GC (<UNSET>)";
2786 case _degenerated_traversal:
2787 return "Pause Degenerated GC (Traversal)";
2788 case _degenerated_outside_cycle:
2789 return "Pause Degenerated GC (Outside of Cycle)";
2790 case _degenerated_mark:
2791 return "Pause Degenerated GC (Mark)";
2792 case _degenerated_evac:
2793 return "Pause Degenerated GC (Evacuation)";
2794 case _degenerated_updaterefs:
2795 return "Pause Degenerated GC (Update Refs)";
2796 default:
2797 ShouldNotReachHere();
2798 return "ERROR";
2799 }
2800 }
2801
2802 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2803 #ifdef ASSERT
2804 assert(_liveness_cache != NULL, "sanity");
2805 assert(worker_id < _max_workers, "sanity");
2806 for (uint i = 0; i < num_regions(); i++) {
2807 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2808 }
2809 #endif
2810 return _liveness_cache[worker_id];
2811 }
2812
2813 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2814 assert(worker_id < _max_workers, "sanity");
2815 assert(_liveness_cache != NULL, "sanity");
2816 jushort* ld = _liveness_cache[worker_id];
2817 for (uint i = 0; i < num_regions(); i++) {
2818 ShenandoahHeapRegion* r = get_region(i);
2819 jushort live = ld[i];
2820 if (live > 0) {
2821 r->increase_live_data_gc_words(live);
2822 ld[i] = 0;
2823 }
2824 }
2825 }
2826
2827 size_t ShenandoahHeap::obj_size(oop obj) const {
2828 return CollectedHeap::obj_size(obj) + ShenandoahForwarding::word_size();
2829 }
2830
2831 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2832 return ShenandoahForwarding::byte_size();
2833 }