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 #if INCLUDE_JFR
70 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
71 #endif
72 #include "memory/metaspace.hpp"
73 #include "oops/compressedOops.inline.hpp"
74 #include "runtime/globals.hpp"
75 #include "runtime/interfaceSupport.inline.hpp"
76 #include "runtime/safepointMechanism.hpp"
77 #include "runtime/vmThread.hpp"
78 #include "services/mallocTracker.hpp"
79
80 #ifdef ASSERT
81 template <class T>
82 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
83 T o = RawAccess<>::oop_load(p);
84 if (! CompressedOops::is_null(o)) {
85 oop obj = CompressedOops::decode_not_null(o);
86 shenandoah_assert_not_forwarded(p, obj);
87 }
88 }
89
90 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
91 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
92 #endif
93
94 class ShenandoahPretouchHeapTask : public AbstractGangTask {
95 private:
96 ShenandoahRegionIterator _regions;
97 const size_t _page_size;
98 public:
99 ShenandoahPretouchHeapTask(size_t page_size) :
100 AbstractGangTask("Shenandoah Pretouch Heap"),
101 _page_size(page_size) {}
102
103 virtual void work(uint worker_id) {
104 ShenandoahHeapRegion* r = _regions.next();
105 while (r != NULL) {
106 os::pretouch_memory(r->bottom(), r->end(), _page_size);
107 r = _regions.next();
108 }
109 }
110 };
111
112 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
113 private:
114 ShenandoahRegionIterator _regions;
115 char* _bitmap_base;
116 const size_t _bitmap_size;
117 const size_t _page_size;
118 public:
119 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
120 AbstractGangTask("Shenandoah Pretouch Bitmap"),
121 _bitmap_base(bitmap_base),
122 _bitmap_size(bitmap_size),
123 _page_size(page_size) {}
124
125 virtual void work(uint worker_id) {
126 ShenandoahHeapRegion* r = _regions.next();
127 while (r != NULL) {
128 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
129 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
130 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
131
132 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
133
134 r = _regions.next();
135 }
136 }
137 };
138
139 jint ShenandoahHeap::initialize() {
140 ShenandoahForwarding::initial_checks();
141
142 initialize_heuristics();
143
144 //
145 // Figure out heap sizing
146 //
147
148 size_t init_byte_size = InitialHeapSize;
149 size_t min_byte_size = MinHeapSize;
150 size_t max_byte_size = MaxHeapSize;
151 size_t heap_alignment = HeapAlignment;
152
153 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
154
155 if (ShenandoahAlwaysPreTouch) {
156 // Enabled pre-touch means the entire heap is committed right away.
157 init_byte_size = max_byte_size;
158 }
159
160 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
161 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
162
163 _num_regions = ShenandoahHeapRegion::region_count();
164
165 size_t num_committed_regions = init_byte_size / reg_size_bytes;
166 num_committed_regions = MIN2(num_committed_regions, _num_regions);
167 assert(num_committed_regions <= _num_regions, "sanity");
168 _initial_size = num_committed_regions * reg_size_bytes;
169
170 size_t num_min_regions = min_byte_size / reg_size_bytes;
171 num_min_regions = MIN2(num_min_regions, _num_regions);
172 assert(num_min_regions <= _num_regions, "sanity");
173 _minimum_size = num_min_regions * reg_size_bytes;
174
175 _committed = _initial_size;
176
177 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
178 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
179
180 //
181 // Reserve and commit memory for heap
182 //
183
184 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
185 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
186 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
187 _heap_region_special = heap_rs.special();
188
189 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
190 "Misaligned heap: " PTR_FORMAT, p2i(base()));
191
192 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
193 if (!_heap_region_special) {
194 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
195 "Cannot commit heap memory");
196 }
197
198 //
199 // Reserve and commit memory for bitmap(s)
200 //
201
202 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
203 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
204
205 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
206
207 guarantee(bitmap_bytes_per_region != 0,
208 "Bitmap bytes per region should not be zero");
209 guarantee(is_power_of_2(bitmap_bytes_per_region),
210 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
211
212 if (bitmap_page_size > bitmap_bytes_per_region) {
213 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
214 _bitmap_bytes_per_slice = bitmap_page_size;
215 } else {
216 _bitmap_regions_per_slice = 1;
217 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
218 }
219
220 guarantee(_bitmap_regions_per_slice >= 1,
221 "Should have at least one region per slice: " SIZE_FORMAT,
222 _bitmap_regions_per_slice);
223
224 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
225 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
226 _bitmap_bytes_per_slice, bitmap_page_size);
227
228 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
229 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
230 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
231 _bitmap_region_special = bitmap.special();
232
233 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
234 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
235 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
236 if (!_bitmap_region_special) {
237 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
238 "Cannot commit bitmap memory");
239 }
240
241 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
242
243 if (ShenandoahVerify) {
244 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
245 if (!verify_bitmap.special()) {
246 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
247 "Cannot commit verification bitmap memory");
248 }
249 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
250 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
251 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
252 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
253 }
254
255 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
256 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
257 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
258 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
259 _aux_bitmap_region_special = aux_bitmap.special();
260 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
261
262 //
263 // Create regions and region sets
264 //
265
266 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
267 _free_set = new ShenandoahFreeSet(this, _num_regions);
268 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
269
270 {
271 ShenandoahHeapLocker locker(lock());
272
273 size_t size_words = ShenandoahHeapRegion::region_size_words();
274
275 for (size_t i = 0; i < _num_regions; i++) {
276 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
277 bool is_committed = i < num_committed_regions;
278 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
279
280 _marking_context->initialize_top_at_mark_start(r);
281 _regions[i] = r;
282 assert(!collection_set()->is_in(i), "New region should not be in collection set");
283 }
284
285 // Initialize to complete
286 _marking_context->mark_complete();
287
288 _free_set->rebuild();
289 }
290
291 if (ShenandoahAlwaysPreTouch) {
292 assert(!AlwaysPreTouch, "Should have been overridden");
293
294 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
295 // before initialize() below zeroes it with initializing thread. For any given region,
296 // we touch the region and the corresponding bitmaps from the same thread.
297 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
298
299 size_t pretouch_heap_page_size = heap_page_size;
300 size_t pretouch_bitmap_page_size = bitmap_page_size;
301
302 #ifdef LINUX
303 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
304 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
305 // them into huge one. Therefore, we need to pretouch with smaller pages.
306 if (UseTransparentHugePages) {
307 pretouch_heap_page_size = (size_t)os::vm_page_size();
308 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
309 }
310 #endif
311
312 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
313 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
314
315 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
316 _num_regions, pretouch_bitmap_page_size);
317 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
318 _workers->run_task(&bcl);
319
320 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
321 _num_regions, pretouch_heap_page_size);
322 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
323 _workers->run_task(&hcl);
324 }
325
326 //
327 // Initialize the rest of GC subsystems
328 //
329
330 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
331 for (uint worker = 0; worker < _max_workers; worker++) {
332 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
333 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
334 }
335
336 // The call below uses stuff (the SATB* things) that are in G1, but probably
337 // belong into a shared location.
338 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
339 SATB_Q_CBL_mon,
340 20 /* G1SATBProcessCompletedThreshold */,
341 60 /* G1SATBBufferEnqueueingThresholdPercent */);
342
343 _monitoring_support = new ShenandoahMonitoringSupport(this);
344 _phase_timings = new ShenandoahPhaseTimings();
345 ShenandoahStringDedup::initialize();
346 ShenandoahCodeRoots::initialize();
347
348 if (ShenandoahAllocationTrace) {
349 _alloc_tracker = new ShenandoahAllocTracker();
350 }
351
352 if (ShenandoahPacing) {
353 _pacer = new ShenandoahPacer(this);
354 _pacer->setup_for_idle();
355 } else {
356 _pacer = NULL;
357 }
358
359 _traversal_gc = heuristics()->can_do_traversal_gc() ?
360 new ShenandoahTraversalGC(this, _num_regions) :
361 NULL;
362
363 _control_thread = new ShenandoahControlThread();
364
365 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
366 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
367 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
368 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
369 );
370
371 log_info(gc, init)("Safepointing mechanism: %s",
372 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
373 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
374
375 return JNI_OK;
376 }
377
378 void ShenandoahHeap::initialize_heuristics() {
379 if (ShenandoahGCHeuristics != NULL) {
380 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
381 _heuristics = new ShenandoahAggressiveHeuristics();
382 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
383 _heuristics = new ShenandoahStaticHeuristics();
384 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
385 _heuristics = new ShenandoahAdaptiveHeuristics();
386 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
387 _heuristics = new ShenandoahPassiveHeuristics();
388 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
389 _heuristics = new ShenandoahCompactHeuristics();
390 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
391 _heuristics = new ShenandoahTraversalHeuristics();
392 } else {
393 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
394 }
395
396 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
397 vm_exit_during_initialization(
398 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
399 _heuristics->name()));
400 }
401 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
402 vm_exit_during_initialization(
403 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
404 _heuristics->name()));
405 }
406 log_info(gc, init)("Shenandoah heuristics: %s",
407 _heuristics->name());
408 } else {
409 ShouldNotReachHere();
410 }
411
412 }
413
414 #ifdef _MSC_VER
415 #pragma warning( push )
416 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
417 #endif
418
419 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
420 CollectedHeap(),
421 _initial_size(0),
422 _used(0),
423 _committed(0),
424 _bytes_allocated_since_gc_start(0),
425 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
426 _workers(NULL),
427 _safepoint_workers(NULL),
428 _heap_region_special(false),
429 _num_regions(0),
430 _regions(NULL),
431 _update_refs_iterator(this),
432 _control_thread(NULL),
433 _shenandoah_policy(policy),
434 _heuristics(NULL),
435 _free_set(NULL),
436 _scm(new ShenandoahConcurrentMark()),
437 _traversal_gc(NULL),
438 _full_gc(new ShenandoahMarkCompact()),
439 _pacer(NULL),
440 _verifier(NULL),
441 _alloc_tracker(NULL),
442 _phase_timings(NULL),
443 _monitoring_support(NULL),
444 _memory_pool(NULL),
445 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
446 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
447 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
448 _soft_ref_policy(),
449 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
450 _ref_processor(NULL),
451 _marking_context(NULL),
452 _bitmap_size(0),
453 _bitmap_regions_per_slice(0),
454 _bitmap_bytes_per_slice(0),
455 _bitmap_region_special(false),
456 _aux_bitmap_region_special(false),
457 _liveness_cache(NULL),
458 _collection_set(NULL)
459 {
460 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
461 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
462
463 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
464
465 _max_workers = MAX2(_max_workers, 1U);
466 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
467 /* are_GC_task_threads */ true,
468 /* are_ConcurrentGC_threads */ true);
469 if (_workers == NULL) {
470 vm_exit_during_initialization("Failed necessary allocation.");
471 } else {
472 _workers->initialize_workers();
473 }
474
475 if (ShenandoahParallelSafepointThreads > 1) {
476 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
477 ShenandoahParallelSafepointThreads,
478 /* are_GC_task_threads */ false,
479 /* are_ConcurrentGC_threads */ false);
480 _safepoint_workers->initialize_workers();
481 }
482 }
483
484 #ifdef _MSC_VER
485 #pragma warning( pop )
486 #endif
487
488 class ShenandoahResetBitmapTask : public AbstractGangTask {
489 private:
490 ShenandoahRegionIterator _regions;
491
492 public:
493 ShenandoahResetBitmapTask() :
494 AbstractGangTask("Parallel Reset Bitmap Task") {}
495
496 void work(uint worker_id) {
497 ShenandoahHeapRegion* region = _regions.next();
498 ShenandoahHeap* heap = ShenandoahHeap::heap();
499 ShenandoahMarkingContext* const ctx = heap->marking_context();
500 while (region != NULL) {
501 if (heap->is_bitmap_slice_committed(region)) {
502 ctx->clear_bitmap(region);
503 }
504 region = _regions.next();
505 }
506 }
507 };
508
509 void ShenandoahHeap::reset_mark_bitmap() {
510 assert_gc_workers(_workers->active_workers());
511 mark_incomplete_marking_context();
512
513 ShenandoahResetBitmapTask task;
514 _workers->run_task(&task);
515 }
516
517 void ShenandoahHeap::print_on(outputStream* st) const {
518 st->print_cr("Shenandoah Heap");
519 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
520 max_capacity() / K, committed() / K, used() / K);
521 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
522 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
523
524 st->print("Status: ");
525 if (has_forwarded_objects()) st->print("has forwarded objects, ");
526 if (is_concurrent_mark_in_progress()) st->print("marking, ");
527 if (is_evacuation_in_progress()) st->print("evacuating, ");
528 if (is_update_refs_in_progress()) st->print("updating refs, ");
529 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
530 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
531 if (is_full_gc_in_progress()) st->print("full gc, ");
532 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
533
534 if (cancelled_gc()) {
535 st->print("cancelled");
536 } else {
537 st->print("not cancelled");
538 }
539 st->cr();
540
541 st->print_cr("Reserved region:");
542 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
543 p2i(reserved_region().start()),
544 p2i(reserved_region().end()));
545
546 ShenandoahCollectionSet* cset = collection_set();
547 st->print_cr("Collection set:");
548 if (cset != NULL) {
549 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
550 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
551 } else {
552 st->print_cr(" (NULL)");
553 }
554
555 st->cr();
556 MetaspaceUtils::print_on(st);
557
558 if (Verbose) {
559 print_heap_regions_on(st);
560 }
561 }
562
563 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
564 public:
565 void do_thread(Thread* thread) {
566 assert(thread != NULL, "Sanity");
567 assert(thread->is_Worker_thread(), "Only worker thread expected");
568 ShenandoahThreadLocalData::initialize_gclab(thread);
569 }
570 };
571
572 void ShenandoahHeap::post_initialize() {
573 CollectedHeap::post_initialize();
574 MutexLocker ml(Threads_lock);
575
576 ShenandoahInitWorkerGCLABClosure init_gclabs;
577 _workers->threads_do(&init_gclabs);
578
579 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
580 // Now, we will let WorkGang to initialize gclab when new worker is created.
581 _workers->set_initialize_gclab();
582
583 _scm->initialize(_max_workers);
584 _full_gc->initialize(_gc_timer);
585
586 ref_processing_init();
587
588 _heuristics->initialize();
589
590 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers());
591 }
592
593 size_t ShenandoahHeap::used() const {
594 return OrderAccess::load_acquire(&_used);
595 }
596
597 size_t ShenandoahHeap::committed() const {
598 OrderAccess::acquire();
599 return _committed;
600 }
601
602 void ShenandoahHeap::increase_committed(size_t bytes) {
603 assert_heaplock_or_safepoint();
604 _committed += bytes;
605 }
606
607 void ShenandoahHeap::decrease_committed(size_t bytes) {
608 assert_heaplock_or_safepoint();
609 _committed -= bytes;
610 }
611
612 void ShenandoahHeap::increase_used(size_t bytes) {
613 Atomic::add(bytes, &_used);
614 }
615
616 void ShenandoahHeap::set_used(size_t bytes) {
617 OrderAccess::release_store_fence(&_used, bytes);
618 }
619
620 void ShenandoahHeap::decrease_used(size_t bytes) {
621 assert(used() >= bytes, "never decrease heap size by more than we've left");
622 Atomic::sub(bytes, &_used);
623 }
624
625 void ShenandoahHeap::increase_allocated(size_t bytes) {
626 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
627 }
628
629 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
630 size_t bytes = words * HeapWordSize;
631 if (!waste) {
632 increase_used(bytes);
633 }
634 increase_allocated(bytes);
635 if (ShenandoahPacing) {
636 control_thread()->pacing_notify_alloc(words);
637 if (waste) {
638 pacer()->claim_for_alloc(words, true);
639 }
640 }
641 }
642
643 size_t ShenandoahHeap::capacity() const {
644 return committed();
645 }
646
647 size_t ShenandoahHeap::max_capacity() const {
648 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
649 }
650
651 size_t ShenandoahHeap::min_capacity() const {
652 return _minimum_size;
653 }
654
655 size_t ShenandoahHeap::initial_capacity() const {
656 return _initial_size;
657 }
658
659 bool ShenandoahHeap::is_in(const void* p) const {
660 HeapWord* heap_base = (HeapWord*) base();
661 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
662 return p >= heap_base && p < last_region_end;
663 }
664
665 void ShenandoahHeap::op_uncommit(double shrink_before) {
666 assert (ShenandoahUncommit, "should be enabled");
667
668 // Application allocates from the beginning of the heap, and GC allocates at
669 // the end of it. It is more efficient to uncommit from the end, so that applications
670 // could enjoy the near committed regions. GC allocations are much less frequent,
671 // and therefore can accept the committing costs.
672
673 size_t count = 0;
674 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
675 ShenandoahHeapRegion* r = get_region(i - 1);
676 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
677 ShenandoahHeapLocker locker(lock());
678 if (r->is_empty_committed()) {
679 // Do not uncommit below minimal capacity
680 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
681 break;
682 }
683
684 r->make_uncommitted();
685 count++;
686 }
687 }
688 SpinPause(); // allow allocators to take the lock
689 }
690
691 if (count > 0) {
692 control_thread()->notify_heap_changed();
693 }
694 }
695
696 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
697 // New object should fit the GCLAB size
698 size_t min_size = MAX2(size, PLAB::min_size());
699
700 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
701 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
702 new_size = MIN2(new_size, PLAB::max_size());
703 new_size = MAX2(new_size, PLAB::min_size());
704
705 // Record new heuristic value even if we take any shortcut. This captures
706 // the case when moderately-sized objects always take a shortcut. At some point,
707 // heuristics should catch up with them.
708 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
709
710 if (new_size < size) {
711 // New size still does not fit the object. Fall back to shared allocation.
712 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
713 return NULL;
714 }
715
716 // Retire current GCLAB, and allocate a new one.
717 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
718 gclab->retire();
719
720 size_t actual_size = 0;
721 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
722 if (gclab_buf == NULL) {
723 return NULL;
724 }
725
726 assert (size <= actual_size, "allocation should fit");
727
728 if (ZeroTLAB) {
729 // ..and clear it.
730 Copy::zero_to_words(gclab_buf, actual_size);
731 } else {
732 // ...and zap just allocated object.
733 #ifdef ASSERT
734 // Skip mangling the space corresponding to the object header to
735 // ensure that the returned space is not considered parsable by
736 // any concurrent GC thread.
737 size_t hdr_size = oopDesc::header_size();
738 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
739 #endif // ASSERT
740 }
741 gclab->set_buf(gclab_buf, actual_size);
742 return gclab->allocate(size);
743 }
744
745 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
746 size_t requested_size,
747 size_t* actual_size) {
748 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
749 HeapWord* res = allocate_memory(req);
750 if (res != NULL) {
751 *actual_size = req.actual_size();
752 } else {
753 *actual_size = 0;
754 }
755 return res;
756 }
757
758 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
759 size_t word_size,
760 size_t* actual_size) {
761 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
762 HeapWord* res = allocate_memory(req);
763 if (res != NULL) {
764 *actual_size = req.actual_size();
765 } else {
766 *actual_size = 0;
767 }
768 return res;
769 }
770
771 ShenandoahHeap* ShenandoahHeap::heap() {
772 CollectedHeap* heap = Universe::heap();
773 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
774 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
775 return (ShenandoahHeap*) heap;
776 }
777
778 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
779 CollectedHeap* heap = Universe::heap();
780 return (ShenandoahHeap*) heap;
781 }
782
783 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
784 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
785
786 intptr_t pacer_epoch = 0;
787 bool in_new_region = false;
788 HeapWord* result = NULL;
789
790 if (req.is_mutator_alloc()) {
791 if (ShenandoahPacing) {
792 pacer()->pace_for_alloc(req.size());
793 pacer_epoch = pacer()->epoch();
794 }
795
796 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
797 result = allocate_memory_under_lock(req, in_new_region);
798 }
799
800 // Allocation failed, block until control thread reacted, then retry allocation.
801 //
802 // It might happen that one of the threads requesting allocation would unblock
803 // way later after GC happened, only to fail the second allocation, because
804 // other threads have already depleted the free storage. In this case, a better
805 // strategy is to try again, as long as GC makes progress.
806 //
807 // Then, we need to make sure the allocation was retried after at least one
808 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
809
810 size_t tries = 0;
811
812 while (result == NULL && _progress_last_gc.is_set()) {
813 tries++;
814 control_thread()->handle_alloc_failure(req.size());
815 result = allocate_memory_under_lock(req, in_new_region);
816 }
817
818 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
819 tries++;
820 control_thread()->handle_alloc_failure(req.size());
821 result = allocate_memory_under_lock(req, in_new_region);
822 }
823
824 } else {
825 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
826 result = allocate_memory_under_lock(req, in_new_region);
827 // Do not call handle_alloc_failure() here, because we cannot block.
828 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
829 }
830
831 if (in_new_region) {
832 control_thread()->notify_heap_changed();
833 }
834
835 if (result != NULL) {
836 size_t requested = req.size();
837 size_t actual = req.actual_size();
838
839 assert (req.is_lab_alloc() || (requested == actual),
840 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
841 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
842
843 if (req.is_mutator_alloc()) {
844 notify_mutator_alloc_words(actual, false);
845
846 // If we requested more than we were granted, give the rest back to pacer.
847 // This only matters if we are in the same pacing epoch: do not try to unpace
848 // over the budget for the other phase.
849 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
850 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
851 }
852 } else {
853 increase_used(actual*HeapWordSize);
854 }
855 }
856
857 return result;
858 }
859
860 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
861 ShenandoahHeapLocker locker(lock());
862 return _free_set->allocate(req, in_new_region);
863 }
864
865 class ShenandoahMemAllocator : public MemAllocator {
866 private:
867 MemAllocator& _initializer;
868 public:
869 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
870 MemAllocator(klass, word_size + ShenandoahForwarding::word_size(), thread),
871 _initializer(initializer) {}
872
873 protected:
874 virtual HeapWord* mem_allocate(Allocation& allocation) const {
875 HeapWord* result = MemAllocator::mem_allocate(allocation);
876 // Initialize brooks-pointer
877 if (result != NULL) {
878 result += ShenandoahForwarding::word_size();
879 ShenandoahForwarding::initialize(oop(result));
880 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
881 }
882 return result;
883 }
884
885 virtual oop initialize(HeapWord* mem) const {
886 return _initializer.initialize(mem);
887 }
888 };
889
890 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
891 ObjAllocator initializer(klass, size, THREAD);
892 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
893 return allocator.allocate();
894 }
895
896 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
897 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
898 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
899 return allocator.allocate();
900 }
901
902 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
903 ClassAllocator initializer(klass, size, THREAD);
904 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
905 return allocator.allocate();
906 }
907
908 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
909 bool* gc_overhead_limit_was_exceeded) {
910 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
911 return allocate_memory(req);
912 }
913
914 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
915 size_t size,
916 Metaspace::MetadataType mdtype) {
917 MetaWord* result;
918
919 // Inform metaspace OOM to GC heuristics if class unloading is possible.
920 if (heuristics()->can_unload_classes()) {
921 ShenandoahHeuristics* h = heuristics();
922 h->record_metaspace_oom();
923 }
924
925 // Expand and retry allocation
926 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
927 if (result != NULL) {
928 return result;
929 }
930
931 // Start full GC
932 collect(GCCause::_metadata_GC_clear_soft_refs);
933
934 // Retry allocation
935 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
936 if (result != NULL) {
937 return result;
938 }
939
940 // Expand and retry allocation
941 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
942 if (result != NULL) {
943 return result;
944 }
945
946 // Out of memory
947 return NULL;
948 }
949
950 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
951 HeapWord* obj = tlab_post_allocation_setup(start);
952 CollectedHeap::fill_with_object(obj, end);
953 }
954
955 size_t ShenandoahHeap::min_dummy_object_size() const {
956 return CollectedHeap::min_dummy_object_size() + ShenandoahForwarding::word_size();
957 }
958
959 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
960 private:
961 ShenandoahHeap* const _heap;
962 Thread* const _thread;
963 public:
964 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
965 _heap(heap), _thread(Thread::current()) {}
966
967 void do_object(oop p) {
968 shenandoah_assert_marked(NULL, p);
969 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
970 _heap->evacuate_object(p, _thread);
971 }
972 }
973 };
974
975 class ShenandoahEvacuationTask : public AbstractGangTask {
976 private:
977 ShenandoahHeap* const _sh;
978 ShenandoahCollectionSet* const _cs;
979 bool _concurrent;
980 public:
981 ShenandoahEvacuationTask(ShenandoahHeap* sh,
982 ShenandoahCollectionSet* cs,
983 bool concurrent) :
984 AbstractGangTask("Parallel Evacuation Task"),
985 _sh(sh),
986 _cs(cs),
987 _concurrent(concurrent)
988 {}
989
990 void work(uint worker_id) {
991 if (_concurrent) {
992 ShenandoahConcurrentWorkerSession worker_session(worker_id);
993 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
994 ShenandoahEvacOOMScope oom_evac_scope;
995 do_work();
996 } else {
997 ShenandoahParallelWorkerSession worker_session(worker_id);
998 ShenandoahEvacOOMScope oom_evac_scope;
999 do_work();
1000 }
1001 }
1002
1003 private:
1004 void do_work() {
1005 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
1006 ShenandoahHeapRegion* r;
1007 while ((r =_cs->claim_next()) != NULL) {
1008 assert(r->has_live(), "all-garbage regions are reclaimed early");
1009 _sh->marked_object_iterate(r, &cl);
1010
1011 if (ShenandoahPacing) {
1012 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1013 }
1014
1015 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
1016 break;
1017 }
1018 }
1019 }
1020 };
1021
1022 void ShenandoahHeap::trash_cset_regions() {
1023 ShenandoahHeapLocker locker(lock());
1024
1025 ShenandoahCollectionSet* set = collection_set();
1026 ShenandoahHeapRegion* r;
1027 set->clear_current_index();
1028 while ((r = set->next()) != NULL) {
1029 r->make_trash();
1030 }
1031 collection_set()->clear();
1032 }
1033
1034 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1035 st->print_cr("Heap Regions:");
1036 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1037 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1038 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1039 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1040
1041 for (size_t i = 0; i < num_regions(); i++) {
1042 get_region(i)->print_on(st);
1043 }
1044 }
1045
1046 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1047 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1048
1049 oop humongous_obj = oop(start->bottom() + ShenandoahForwarding::word_size());
1050 size_t size = humongous_obj->size() + ShenandoahForwarding::word_size();
1051 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1052 size_t index = start->region_number() + required_regions - 1;
1053
1054 assert(!start->has_live(), "liveness must be zero");
1055
1056 for(size_t i = 0; i < required_regions; i++) {
1057 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1058 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1059 ShenandoahHeapRegion* region = get_region(index --);
1060
1061 assert(region->is_humongous(), "expect correct humongous start or continuation");
1062 assert(!region->is_cset(), "Humongous region should not be in collection set");
1063
1064 region->make_trash_immediate();
1065 }
1066 }
1067
1068 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1069 public:
1070 void do_thread(Thread* thread) {
1071 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1072 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1073 gclab->retire();
1074 }
1075 };
1076
1077 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1078 if (UseTLAB) {
1079 CollectedHeap::ensure_parsability(retire_tlabs);
1080 }
1081 ShenandoahRetireGCLABClosure cl;
1082 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1083 cl.do_thread(t);
1084 }
1085 workers()->threads_do(&cl);
1086 }
1087
1088 void ShenandoahHeap::resize_tlabs() {
1089 CollectedHeap::resize_all_tlabs();
1090 }
1091
1092 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1093 private:
1094 ShenandoahRootEvacuator* _rp;
1095
1096 public:
1097 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1098 AbstractGangTask("Shenandoah evacuate and update roots"),
1099 _rp(rp) {}
1100
1101 void work(uint worker_id) {
1102 ShenandoahParallelWorkerSession worker_session(worker_id);
1103 ShenandoahEvacOOMScope oom_evac_scope;
1104 ShenandoahEvacuateUpdateRootsClosure cl;
1105 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1106 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1107 }
1108 };
1109
1110 void ShenandoahHeap::evacuate_and_update_roots() {
1111 #if defined(COMPILER2) || INCLUDE_JVMCI
1112 DerivedPointerTable::clear();
1113 #endif
1114 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1115
1116 {
1117 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1118 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1119 workers()->run_task(&roots_task);
1120 }
1121
1122 #if defined(COMPILER2) || INCLUDE_JVMCI
1123 DerivedPointerTable::update_pointers();
1124 #endif
1125 }
1126
1127 // Returns size in bytes
1128 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1129 if (ShenandoahElasticTLAB) {
1130 // With Elastic TLABs, return the max allowed size, and let the allocation path
1131 // figure out the safe size for current allocation.
1132 return ShenandoahHeapRegion::max_tlab_size_bytes();
1133 } else {
1134 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1135 }
1136 }
1137
1138 size_t ShenandoahHeap::max_tlab_size() const {
1139 // Returns size in words
1140 return ShenandoahHeapRegion::max_tlab_size_words();
1141 }
1142
1143 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1144 public:
1145 void do_thread(Thread* thread) {
1146 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1147 gclab->retire();
1148 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1149 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1150 }
1151 }
1152 };
1153
1154 void ShenandoahHeap::retire_and_reset_gclabs() {
1155 ShenandoahRetireAndResetGCLABClosure cl;
1156 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1157 cl.do_thread(t);
1158 }
1159 workers()->threads_do(&cl);
1160 }
1161
1162 void ShenandoahHeap::collect(GCCause::Cause cause) {
1163 control_thread()->request_gc(cause);
1164 }
1165
1166 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1167 //assert(false, "Shouldn't need to do full collections");
1168 }
1169
1170 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1171 Space* sp = heap_region_containing(addr);
1172 if (sp != NULL) {
1173 return sp->block_start(addr);
1174 }
1175 return NULL;
1176 }
1177
1178 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1179 Space* sp = heap_region_containing(addr);
1180 return sp->block_is_obj(addr);
1181 }
1182
1183 jlong ShenandoahHeap::millis_since_last_gc() {
1184 double v = heuristics()->time_since_last_gc() * 1000;
1185 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1186 return (jlong)v;
1187 }
1188
1189 void ShenandoahHeap::prepare_for_verify() {
1190 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1191 make_parsable(false);
1192 }
1193 }
1194
1195 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1196 workers()->print_worker_threads_on(st);
1197 if (ShenandoahStringDedup::is_enabled()) {
1198 ShenandoahStringDedup::print_worker_threads_on(st);
1199 }
1200 }
1201
1202 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1203 workers()->threads_do(tcl);
1204 if (_safepoint_workers != NULL) {
1205 _safepoint_workers->threads_do(tcl);
1206 }
1207 if (ShenandoahStringDedup::is_enabled()) {
1208 ShenandoahStringDedup::threads_do(tcl);
1209 }
1210 }
1211
1212 void ShenandoahHeap::print_tracing_info() const {
1213 LogTarget(Info, gc, stats) lt;
1214 if (lt.is_enabled()) {
1215 ResourceMark rm;
1216 LogStream ls(lt);
1217
1218 phase_timings()->print_on(&ls);
1219
1220 ls.cr();
1221 ls.cr();
1222
1223 shenandoah_policy()->print_gc_stats(&ls);
1224
1225 ls.cr();
1226 ls.cr();
1227
1228 if (ShenandoahPacing) {
1229 pacer()->print_on(&ls);
1230 }
1231
1232 ls.cr();
1233 ls.cr();
1234
1235 if (ShenandoahAllocationTrace) {
1236 assert(alloc_tracker() != NULL, "Must be");
1237 alloc_tracker()->print_on(&ls);
1238 } else {
1239 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1240 }
1241 }
1242 }
1243
1244 void ShenandoahHeap::verify(VerifyOption vo) {
1245 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1246 if (ShenandoahVerify) {
1247 verifier()->verify_generic(vo);
1248 } else {
1249 // TODO: Consider allocating verification bitmaps on demand,
1250 // and turn this on unconditionally.
1251 }
1252 }
1253 }
1254 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1255 return _free_set->capacity();
1256 }
1257
1258 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1259 private:
1260 MarkBitMap* _bitmap;
1261 Stack<oop,mtGC>* _oop_stack;
1262
1263 template <class T>
1264 void do_oop_work(T* p) {
1265 T o = RawAccess<>::oop_load(p);
1266 if (!CompressedOops::is_null(o)) {
1267 oop obj = CompressedOops::decode_not_null(o);
1268 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1269 assert(oopDesc::is_oop(obj), "must be a valid oop");
1270 if (!_bitmap->is_marked((HeapWord*) obj)) {
1271 _bitmap->mark((HeapWord*) obj);
1272 _oop_stack->push(obj);
1273 }
1274 }
1275 }
1276 public:
1277 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1278 _bitmap(bitmap), _oop_stack(oop_stack) {}
1279 void do_oop(oop* p) { do_oop_work(p); }
1280 void do_oop(narrowOop* p) { do_oop_work(p); }
1281 };
1282
1283 /*
1284 * This is public API, used in preparation of object_iterate().
1285 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1286 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1287 * control, we call SH::make_tlabs_parsable().
1288 */
1289 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1290 // No-op.
1291 }
1292
1293 /*
1294 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1295 *
1296 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1297 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1298 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1299 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1300 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1301 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1302 * wiped the bitmap in preparation for next marking).
1303 *
1304 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1305 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1306 * is allowed to report dead objects, but is not required to do so.
1307 */
1308 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1309 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1310 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1311 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1312 return;
1313 }
1314
1315 // Reset bitmap
1316 _aux_bit_map.clear();
1317
1318 Stack<oop,mtGC> oop_stack;
1319
1320 // First, we process all GC roots. This populates the work stack with initial objects.
1321 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1322 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1323 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1324 CodeBlobToOopClosure blobs(&oops, false);
1325 rp.process_all_roots(&oops, &clds, &blobs, NULL, 0);
1326
1327 // Work through the oop stack to traverse heap.
1328 while (! oop_stack.is_empty()) {
1329 oop obj = oop_stack.pop();
1330 assert(oopDesc::is_oop(obj), "must be a valid oop");
1331 cl->do_object(obj);
1332 obj->oop_iterate(&oops);
1333 }
1334
1335 assert(oop_stack.is_empty(), "should be empty");
1336
1337 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1338 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1339 }
1340 }
1341
1342 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1343 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1344 object_iterate(cl);
1345 }
1346
1347 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1348 for (size_t i = 0; i < num_regions(); i++) {
1349 ShenandoahHeapRegion* current = get_region(i);
1350 blk->heap_region_do(current);
1351 }
1352 }
1353
1354 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1355 private:
1356 ShenandoahHeap* const _heap;
1357 ShenandoahHeapRegionClosure* const _blk;
1358
1359 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1360 volatile size_t _index;
1361 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1362
1363 public:
1364 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1365 AbstractGangTask("Parallel Region Task"),
1366 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1367
1368 void work(uint worker_id) {
1369 size_t stride = ShenandoahParallelRegionStride;
1370
1371 size_t max = _heap->num_regions();
1372 while (_index < max) {
1373 size_t cur = Atomic::add(stride, &_index) - stride;
1374 size_t start = cur;
1375 size_t end = MIN2(cur + stride, max);
1376 if (start >= max) break;
1377
1378 for (size_t i = cur; i < end; i++) {
1379 ShenandoahHeapRegion* current = _heap->get_region(i);
1380 _blk->heap_region_do(current);
1381 }
1382 }
1383 }
1384 };
1385
1386 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1387 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1388 if (num_regions() > ShenandoahParallelRegionStride) {
1389 ShenandoahParallelHeapRegionTask task(blk);
1390 workers()->run_task(&task);
1391 } else {
1392 heap_region_iterate(blk);
1393 }
1394 }
1395
1396 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1397 private:
1398 ShenandoahMarkingContext* const _ctx;
1399 public:
1400 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1401
1402 void heap_region_do(ShenandoahHeapRegion* r) {
1403 if (r->is_active()) {
1404 r->clear_live_data();
1405 _ctx->capture_top_at_mark_start(r);
1406 } else {
1407 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1408 assert(_ctx->top_at_mark_start(r) == r->top(),
1409 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1410 }
1411 }
1412
1413 bool is_thread_safe() { return true; }
1414 };
1415
1416 void ShenandoahHeap::op_init_mark() {
1417 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1418 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1419
1420 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1421 assert(!marking_context()->is_complete(), "should not be complete");
1422
1423 if (ShenandoahVerify) {
1424 verifier()->verify_before_concmark();
1425 }
1426
1427 if (VerifyBeforeGC) {
1428 Universe::verify();
1429 }
1430
1431 set_concurrent_mark_in_progress(true);
1432 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1433 {
1434 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1435 make_parsable(true);
1436 }
1437
1438 {
1439 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1440 ShenandoahClearLivenessClosure clc;
1441 parallel_heap_region_iterate(&clc);
1442 }
1443
1444 // Make above changes visible to worker threads
1445 OrderAccess::fence();
1446
1447 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1448
1449 if (UseTLAB) {
1450 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1451 resize_tlabs();
1452 }
1453
1454 if (ShenandoahPacing) {
1455 pacer()->setup_for_mark();
1456 }
1457 }
1458
1459 void ShenandoahHeap::op_mark() {
1460 concurrent_mark()->mark_from_roots();
1461 }
1462
1463 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1464 private:
1465 ShenandoahMarkingContext* const _ctx;
1466 public:
1467 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1468
1469 void heap_region_do(ShenandoahHeapRegion* r) {
1470 if (r->is_active()) {
1471 HeapWord *tams = _ctx->top_at_mark_start(r);
1472 HeapWord *top = r->top();
1473 if (top > tams) {
1474 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1475 }
1476 } else {
1477 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1478 assert(_ctx->top_at_mark_start(r) == r->top(),
1479 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1480 }
1481 }
1482
1483 bool is_thread_safe() { return true; }
1484 };
1485
1486 void ShenandoahHeap::op_final_mark() {
1487 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1488
1489 // It is critical that we
1490 // evacuate roots right after finishing marking, so that we don't
1491 // get unmarked objects in the roots.
1492
1493 if (!cancelled_gc()) {
1494 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1495
1496 // Degen may be caused by failed evacuation of roots
1497 if (is_degenerated_gc_in_progress() && has_forwarded_objects()) {
1498 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
1499 }
1500
1501 if (ShenandoahVerify) {
1502 verifier()->verify_roots_no_forwarded();
1503 }
1504
1505 stop_concurrent_marking();
1506
1507 {
1508 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1509
1510 // All allocations past TAMS are implicitly live, adjust the region data.
1511 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1512 ShenandoahCompleteLivenessClosure cl;
1513 parallel_heap_region_iterate(&cl);
1514 }
1515
1516 {
1517 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1518
1519 make_parsable(true);
1520
1521 trash_cset_regions();
1522
1523 {
1524 ShenandoahHeapLocker locker(lock());
1525 _collection_set->clear();
1526 _free_set->clear();
1527
1528 heuristics()->choose_collection_set(_collection_set);
1529
1530 _free_set->rebuild();
1531 }
1532 }
1533
1534 // If collection set has candidates, start evacuation.
1535 // Otherwise, bypass the rest of the cycle.
1536 if (!collection_set()->is_empty()) {
1537 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1538
1539 if (ShenandoahVerify) {
1540 verifier()->verify_before_evacuation();
1541 }
1542
1543 set_evacuation_in_progress(true);
1544 // From here on, we need to update references.
1545 set_has_forwarded_objects(true);
1546
1547 evacuate_and_update_roots();
1548
1549 if (ShenandoahPacing) {
1550 pacer()->setup_for_evac();
1551 }
1552
1553 if (ShenandoahVerify) {
1554 verifier()->verify_roots_no_forwarded();
1555 verifier()->verify_during_evacuation();
1556 }
1557 } else {
1558 if (ShenandoahVerify) {
1559 verifier()->verify_after_concmark();
1560 }
1561
1562 if (VerifyAfterGC) {
1563 Universe::verify();
1564 }
1565 }
1566
1567 } else {
1568 concurrent_mark()->cancel();
1569 stop_concurrent_marking();
1570
1571 if (process_references()) {
1572 // Abandon reference processing right away: pre-cleaning must have failed.
1573 ReferenceProcessor *rp = ref_processor();
1574 rp->disable_discovery();
1575 rp->abandon_partial_discovery();
1576 rp->verify_no_references_recorded();
1577 }
1578 }
1579 }
1580
1581 void ShenandoahHeap::op_final_evac() {
1582 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1583
1584 set_evacuation_in_progress(false);
1585
1586 retire_and_reset_gclabs();
1587
1588 if (ShenandoahVerify) {
1589 verifier()->verify_after_evacuation();
1590 }
1591
1592 if (VerifyAfterGC) {
1593 Universe::verify();
1594 }
1595 }
1596
1597 void ShenandoahHeap::op_conc_evac() {
1598 ShenandoahEvacuationTask task(this, _collection_set, true);
1599 workers()->run_task(&task);
1600 }
1601
1602 void ShenandoahHeap::op_stw_evac() {
1603 ShenandoahEvacuationTask task(this, _collection_set, false);
1604 workers()->run_task(&task);
1605 }
1606
1607 void ShenandoahHeap::op_updaterefs() {
1608 update_heap_references(true);
1609 }
1610
1611 void ShenandoahHeap::op_cleanup() {
1612 free_set()->recycle_trash();
1613 }
1614
1615 void ShenandoahHeap::op_reset() {
1616 reset_mark_bitmap();
1617 }
1618
1619 void ShenandoahHeap::op_preclean() {
1620 concurrent_mark()->preclean_weak_refs();
1621 }
1622
1623 void ShenandoahHeap::op_init_traversal() {
1624 traversal_gc()->init_traversal_collection();
1625 }
1626
1627 void ShenandoahHeap::op_traversal() {
1628 traversal_gc()->concurrent_traversal_collection();
1629 }
1630
1631 void ShenandoahHeap::op_final_traversal() {
1632 traversal_gc()->final_traversal_collection();
1633 }
1634
1635 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1636 ShenandoahMetricsSnapshot metrics;
1637 metrics.snap_before();
1638
1639 full_gc()->do_it(cause);
1640 if (UseTLAB) {
1641 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1642 resize_all_tlabs();
1643 }
1644
1645 metrics.snap_after();
1646 metrics.print();
1647
1648 if (metrics.is_good_progress("Full GC")) {
1649 _progress_last_gc.set();
1650 } else {
1651 // Nothing to do. Tell the allocation path that we have failed to make
1652 // progress, and it can finally fail.
1653 _progress_last_gc.unset();
1654 }
1655 }
1656
1657 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1658 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1659 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1660 // some phase, we have to upgrade the Degenerate GC to Full GC.
1661
1662 clear_cancelled_gc();
1663
1664 ShenandoahMetricsSnapshot metrics;
1665 metrics.snap_before();
1666
1667 switch (point) {
1668 case _degenerated_traversal:
1669 {
1670 // Drop the collection set. Note: this leaves some already forwarded objects
1671 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1672 // workarounds in ShenandoahTraversalHeuristics.
1673
1674 ShenandoahHeapLocker locker(lock());
1675 collection_set()->clear_current_index();
1676 for (size_t i = 0; i < collection_set()->count(); i++) {
1677 ShenandoahHeapRegion* r = collection_set()->next();
1678 r->make_regular_bypass();
1679 }
1680 collection_set()->clear();
1681 }
1682 op_final_traversal();
1683 op_cleanup();
1684 return;
1685
1686 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1687 // but enters it at different points, depending on which concurrent phase had
1688 // degenerated.
1689
1690 case _degenerated_outside_cycle:
1691 // We have degenerated from outside the cycle, which means something is bad with
1692 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1693 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1694 // we can do the most aggressive degen cycle, which includes processing references and
1695 // class unloading, unless those features are explicitly disabled.
1696 //
1697 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1698 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1699 set_process_references(heuristics()->can_process_references());
1700 set_unload_classes(heuristics()->can_unload_classes());
1701
1702 if (heuristics()->can_do_traversal_gc()) {
1703 // Not possible to degenerate from here, upgrade to Full GC right away.
1704 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1705 op_degenerated_fail();
1706 return;
1707 }
1708
1709 op_reset();
1710
1711 op_init_mark();
1712 if (cancelled_gc()) {
1713 op_degenerated_fail();
1714 return;
1715 }
1716
1717 case _degenerated_mark:
1718 op_final_mark();
1719 if (cancelled_gc()) {
1720 op_degenerated_fail();
1721 return;
1722 }
1723
1724 op_cleanup();
1725
1726 case _degenerated_evac:
1727 // If heuristics thinks we should do the cycle, this flag would be set,
1728 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1729 if (is_evacuation_in_progress()) {
1730
1731 // Degeneration under oom-evac protocol might have left some objects in
1732 // collection set un-evacuated. Restart evacuation from the beginning to
1733 // capture all objects. For all the objects that are already evacuated,
1734 // it would be a simple check, which is supposed to be fast. This is also
1735 // safe to do even without degeneration, as CSet iterator is at beginning
1736 // in preparation for evacuation anyway.
1737 collection_set()->clear_current_index();
1738
1739 op_stw_evac();
1740 if (cancelled_gc()) {
1741 op_degenerated_fail();
1742 return;
1743 }
1744 }
1745
1746 // If heuristics thinks we should do the cycle, this flag would be set,
1747 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1748 if (has_forwarded_objects()) {
1749 op_init_updaterefs();
1750 if (cancelled_gc()) {
1751 op_degenerated_fail();
1752 return;
1753 }
1754 }
1755
1756 case _degenerated_updaterefs:
1757 if (has_forwarded_objects()) {
1758 op_final_updaterefs();
1759 if (cancelled_gc()) {
1760 op_degenerated_fail();
1761 return;
1762 }
1763 }
1764
1765 op_cleanup();
1766 break;
1767
1768 default:
1769 ShouldNotReachHere();
1770 }
1771
1772 if (ShenandoahVerify) {
1773 verifier()->verify_after_degenerated();
1774 }
1775
1776 if (VerifyAfterGC) {
1777 Universe::verify();
1778 }
1779
1780 metrics.snap_after();
1781 metrics.print();
1782
1783 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1784 // because that probably means the heap is overloaded and/or fragmented.
1785 if (!metrics.is_good_progress("Degenerated GC")) {
1786 _progress_last_gc.unset();
1787 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1788 op_degenerated_futile();
1789 } else {
1790 _progress_last_gc.set();
1791 }
1792 }
1793
1794 void ShenandoahHeap::op_degenerated_fail() {
1795 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1796 shenandoah_policy()->record_degenerated_upgrade_to_full();
1797 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1798 }
1799
1800 void ShenandoahHeap::op_degenerated_futile() {
1801 shenandoah_policy()->record_degenerated_upgrade_to_full();
1802 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1803 }
1804
1805 void ShenandoahHeap::stop_concurrent_marking() {
1806 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1807 set_concurrent_mark_in_progress(false);
1808 if (!cancelled_gc()) {
1809 // If we needed to update refs, and concurrent marking has been cancelled,
1810 // we need to finish updating references.
1811 set_has_forwarded_objects(false);
1812 mark_complete_marking_context();
1813 }
1814 }
1815
1816 void ShenandoahHeap::force_satb_flush_all_threads() {
1817 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1818 // No need to flush SATBs
1819 return;
1820 }
1821
1822 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1823 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1824 }
1825 // The threads are not "acquiring" their thread-local data, but it does not
1826 // hurt to "release" the updates here anyway.
1827 OrderAccess::fence();
1828 }
1829
1830 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1831 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1832 ShenandoahThreadLocalData::set_gc_state(t, state);
1833 }
1834 }
1835
1836 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1837 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1838 _gc_state.set_cond(mask, value);
1839 set_gc_state_all_threads(_gc_state.raw_value());
1840 }
1841
1842 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1843 if (has_forwarded_objects()) {
1844 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
1845 } else {
1846 set_gc_state_mask(MARKING, in_progress);
1847 }
1848 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1849 }
1850
1851 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1852 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED | UPDATEREFS, in_progress);
1853 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1854 }
1855
1856 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1857 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1858 set_gc_state_mask(EVACUATION, in_progress);
1859 }
1860
1861 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1862 // Initialize Brooks pointer for the next object
1863 HeapWord* result = obj + ShenandoahForwarding::word_size();
1864 ShenandoahForwarding::initialize(oop(result));
1865 return result;
1866 }
1867
1868 void ShenandoahHeap::ref_processing_init() {
1869 assert(_max_workers > 0, "Sanity");
1870
1871 _ref_processor =
1872 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1873 ParallelRefProcEnabled, // MT processing
1874 _max_workers, // Degree of MT processing
1875 true, // MT discovery
1876 _max_workers, // Degree of MT discovery
1877 false, // Reference discovery is not atomic
1878 NULL, // No closure, should be installed before use
1879 true); // Scale worker threads
1880
1881 shenandoah_assert_rp_isalive_not_installed();
1882 }
1883
1884 GCTracer* ShenandoahHeap::tracer() {
1885 return shenandoah_policy()->tracer();
1886 }
1887
1888 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1889 return _free_set->used();
1890 }
1891
1892 bool ShenandoahHeap::try_cancel_gc() {
1893 while (true) {
1894 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1895 if (prev == CANCELLABLE) return true;
1896 else if (prev == CANCELLED) return false;
1897 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1898 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1899 {
1900 // We need to provide a safepoint here, otherwise we might
1901 // spin forever if a SP is pending.
1902 ThreadBlockInVM sp(JavaThread::current());
1903 SpinPause();
1904 }
1905 }
1906 }
1907
1908 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1909 if (try_cancel_gc()) {
1910 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1911 log_info(gc)("%s", msg.buffer());
1912 Events::log(Thread::current(), "%s", msg.buffer());
1913 }
1914 }
1915
1916 uint ShenandoahHeap::max_workers() {
1917 return _max_workers;
1918 }
1919
1920 void ShenandoahHeap::stop() {
1921 // The shutdown sequence should be able to terminate when GC is running.
1922
1923 // Step 0. Notify policy to disable event recording.
1924 _shenandoah_policy->record_shutdown();
1925
1926 // Step 1. Notify control thread that we are in shutdown.
1927 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1928 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1929 control_thread()->prepare_for_graceful_shutdown();
1930
1931 // Step 2. Notify GC workers that we are cancelling GC.
1932 cancel_gc(GCCause::_shenandoah_stop_vm);
1933
1934 // Step 3. Wait until GC worker exits normally.
1935 control_thread()->stop();
1936
1937 // Step 4. Stop String Dedup thread if it is active
1938 if (ShenandoahStringDedup::is_enabled()) {
1939 ShenandoahStringDedup::stop();
1940 }
1941 }
1942
1943 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1944 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1945
1946 ShenandoahGCPhase root_phase(full_gc ?
1947 ShenandoahPhaseTimings::full_gc_purge :
1948 ShenandoahPhaseTimings::purge);
1949
1950 ShenandoahIsAliveSelector alive;
1951 BoolObjectClosure* is_alive = alive.is_alive_closure();
1952
1953 bool purged_class;
1954
1955 // Unload classes and purge SystemDictionary.
1956 {
1957 ShenandoahGCPhase phase(full_gc ?
1958 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1959 ShenandoahPhaseTimings::purge_class_unload);
1960 purged_class = SystemDictionary::do_unloading(gc_timer());
1961 }
1962
1963 {
1964 ShenandoahGCPhase phase(full_gc ?
1965 ShenandoahPhaseTimings::full_gc_purge_par :
1966 ShenandoahPhaseTimings::purge_par);
1967 uint active = _workers->active_workers();
1968 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1969 _workers->run_task(&unlink_task);
1970 }
1971
1972 {
1973 ShenandoahGCPhase phase(full_gc ?
1974 ShenandoahPhaseTimings::full_gc_purge_cldg :
1975 ShenandoahPhaseTimings::purge_cldg);
1976 ClassLoaderDataGraph::purge();
1977 }
1978 }
1979
1980 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1981 set_gc_state_mask(HAS_FORWARDED, cond);
1982 }
1983
1984 void ShenandoahHeap::set_process_references(bool pr) {
1985 _process_references.set_cond(pr);
1986 }
1987
1988 void ShenandoahHeap::set_unload_classes(bool uc) {
1989 _unload_classes.set_cond(uc);
1990 }
1991
1992 bool ShenandoahHeap::process_references() const {
1993 return _process_references.is_set();
1994 }
1995
1996 bool ShenandoahHeap::unload_classes() const {
1997 return _unload_classes.is_set();
1998 }
1999
2000 address ShenandoahHeap::in_cset_fast_test_addr() {
2001 ShenandoahHeap* heap = ShenandoahHeap::heap();
2002 assert(heap->collection_set() != NULL, "Sanity");
2003 return (address) heap->collection_set()->biased_map_address();
2004 }
2005
2006 address ShenandoahHeap::cancelled_gc_addr() {
2007 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2008 }
2009
2010 address ShenandoahHeap::gc_state_addr() {
2011 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2012 }
2013
2014 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2015 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2016 }
2017
2018 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2019 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2020 }
2021
2022 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2023 _degenerated_gc_in_progress.set_cond(in_progress);
2024 }
2025
2026 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2027 _full_gc_in_progress.set_cond(in_progress);
2028 }
2029
2030 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2031 assert (is_full_gc_in_progress(), "should be");
2032 _full_gc_move_in_progress.set_cond(in_progress);
2033 }
2034
2035 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2036 set_gc_state_mask(UPDATEREFS, in_progress);
2037 }
2038
2039 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2040 ShenandoahCodeRoots::add_nmethod(nm);
2041 }
2042
2043 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2044 ShenandoahCodeRoots::remove_nmethod(nm);
2045 }
2046
2047 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2048 ShenandoahHeapLocker locker(lock());
2049 heap_region_containing(o)->make_pinned();
2050 return o;
2051 }
2052
2053 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2054 ShenandoahHeapLocker locker(lock());
2055 heap_region_containing(o)->make_unpinned();
2056 }
2057
2058 GCTimer* ShenandoahHeap::gc_timer() const {
2059 return _gc_timer;
2060 }
2061
2062 #ifdef ASSERT
2063 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2064 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2065
2066 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2067 if (UseDynamicNumberOfGCThreads ||
2068 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2069 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2070 } else {
2071 // Use ParallelGCThreads inside safepoints
2072 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2073 }
2074 } else {
2075 if (UseDynamicNumberOfGCThreads ||
2076 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2077 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2078 } else {
2079 // Use ConcGCThreads outside safepoints
2080 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2081 }
2082 }
2083 }
2084 #endif
2085
2086 ShenandoahVerifier* ShenandoahHeap::verifier() {
2087 guarantee(ShenandoahVerify, "Should be enabled");
2088 assert (_verifier != NULL, "sanity");
2089 return _verifier;
2090 }
2091
2092 template<class T>
2093 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2094 private:
2095 T cl;
2096 ShenandoahHeap* _heap;
2097 ShenandoahRegionIterator* _regions;
2098 bool _concurrent;
2099 public:
2100 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2101 AbstractGangTask("Concurrent Update References Task"),
2102 cl(T()),
2103 _heap(ShenandoahHeap::heap()),
2104 _regions(regions),
2105 _concurrent(concurrent) {
2106 }
2107
2108 void work(uint worker_id) {
2109 if (_concurrent) {
2110 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2111 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2112 do_work();
2113 } else {
2114 ShenandoahParallelWorkerSession worker_session(worker_id);
2115 do_work();
2116 }
2117 }
2118
2119 private:
2120 void do_work() {
2121 ShenandoahHeapRegion* r = _regions->next();
2122 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2123 while (r != NULL) {
2124 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2125 assert (top_at_start_ur >= r->bottom(), "sanity");
2126 if (r->is_active() && !r->is_cset()) {
2127 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2128 }
2129 if (ShenandoahPacing) {
2130 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2131 }
2132 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2133 return;
2134 }
2135 r = _regions->next();
2136 }
2137 }
2138 };
2139
2140 void ShenandoahHeap::update_heap_references(bool concurrent) {
2141 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2142 workers()->run_task(&task);
2143 }
2144
2145 void ShenandoahHeap::op_init_updaterefs() {
2146 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2147
2148 set_evacuation_in_progress(false);
2149
2150 retire_and_reset_gclabs();
2151
2152 if (ShenandoahVerify) {
2153 verifier()->verify_before_updaterefs();
2154 }
2155
2156 set_update_refs_in_progress(true);
2157 make_parsable(true);
2158 for (uint i = 0; i < num_regions(); i++) {
2159 ShenandoahHeapRegion* r = get_region(i);
2160 r->set_concurrent_iteration_safe_limit(r->top());
2161 }
2162
2163 // Reset iterator.
2164 _update_refs_iterator.reset();
2165
2166 if (ShenandoahPacing) {
2167 pacer()->setup_for_updaterefs();
2168 }
2169 }
2170
2171 void ShenandoahHeap::op_final_updaterefs() {
2172 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2173
2174 // Check if there is left-over work, and finish it
2175 if (_update_refs_iterator.has_next()) {
2176 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2177
2178 // Finish updating references where we left off.
2179 clear_cancelled_gc();
2180 update_heap_references(false);
2181 }
2182
2183 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2184 // everything. On degenerated paths, cancelled gc would not be set anyway.
2185 if (cancelled_gc()) {
2186 clear_cancelled_gc();
2187 }
2188 assert(!cancelled_gc(), "Should have been done right before");
2189
2190 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2191 ShenandoahPhaseTimings::degen_gc_update_roots:
2192 ShenandoahPhaseTimings::final_update_refs_roots);
2193
2194 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2195
2196 trash_cset_regions();
2197 set_has_forwarded_objects(false);
2198 set_update_refs_in_progress(false);
2199
2200 if (ShenandoahVerify) {
2201 verifier()->verify_roots_no_forwarded();
2202 verifier()->verify_after_updaterefs();
2203 }
2204
2205 if (VerifyAfterGC) {
2206 Universe::verify();
2207 }
2208
2209 {
2210 ShenandoahHeapLocker locker(lock());
2211 _free_set->rebuild();
2212 }
2213 }
2214
2215 #ifdef ASSERT
2216 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2217 _lock.assert_owned_by_current_thread();
2218 }
2219
2220 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2221 _lock.assert_not_owned_by_current_thread();
2222 }
2223
2224 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2225 _lock.assert_owned_by_current_thread_or_safepoint();
2226 }
2227 #endif
2228
2229 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2230 print_on(st);
2231 print_heap_regions_on(st);
2232 }
2233
2234 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2235 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2236
2237 size_t regions_from = _bitmap_regions_per_slice * slice;
2238 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2239 for (size_t g = regions_from; g < regions_to; g++) {
2240 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2241 if (skip_self && g == r->region_number()) continue;
2242 if (get_region(g)->is_committed()) {
2243 return true;
2244 }
2245 }
2246 return false;
2247 }
2248
2249 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2250 assert_heaplock_owned_by_current_thread();
2251
2252 // Bitmaps in special regions do not need commits
2253 if (_bitmap_region_special) {
2254 return true;
2255 }
2256
2257 if (is_bitmap_slice_committed(r, true)) {
2258 // Some other region from the group is already committed, meaning the bitmap
2259 // slice is already committed, we exit right away.
2260 return true;
2261 }
2262
2263 // Commit the bitmap slice:
2264 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2265 size_t off = _bitmap_bytes_per_slice * slice;
2266 size_t len = _bitmap_bytes_per_slice;
2267 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2268 return false;
2269 }
2270 return true;
2271 }
2272
2273 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2274 assert_heaplock_owned_by_current_thread();
2275
2276 // Bitmaps in special regions do not need uncommits
2277 if (_bitmap_region_special) {
2278 return true;
2279 }
2280
2281 if (is_bitmap_slice_committed(r, true)) {
2282 // Some other region from the group is still committed, meaning the bitmap
2283 // slice is should stay committed, exit right away.
2284 return true;
2285 }
2286
2287 // Uncommit the bitmap slice:
2288 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2289 size_t off = _bitmap_bytes_per_slice * slice;
2290 size_t len = _bitmap_bytes_per_slice;
2291 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2292 return false;
2293 }
2294 return true;
2295 }
2296
2297 void ShenandoahHeap::safepoint_synchronize_begin() {
2298 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2299 SuspendibleThreadSet::synchronize();
2300 }
2301 }
2302
2303 void ShenandoahHeap::safepoint_synchronize_end() {
2304 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2305 SuspendibleThreadSet::desynchronize();
2306 }
2307 }
2308
2309 void ShenandoahHeap::vmop_entry_init_mark() {
2310 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2311 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2312 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2313
2314 try_inject_alloc_failure();
2315 VM_ShenandoahInitMark op;
2316 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2317 }
2318
2319 void ShenandoahHeap::vmop_entry_final_mark() {
2320 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2321 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2322 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2323
2324 try_inject_alloc_failure();
2325 VM_ShenandoahFinalMarkStartEvac op;
2326 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2327 }
2328
2329 void ShenandoahHeap::vmop_entry_final_evac() {
2330 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2331 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2332 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2333
2334 VM_ShenandoahFinalEvac op;
2335 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2336 }
2337
2338 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2339 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2340 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2341 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2342
2343 try_inject_alloc_failure();
2344 VM_ShenandoahInitUpdateRefs op;
2345 VMThread::execute(&op);
2346 }
2347
2348 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2349 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2350 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2351 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2352
2353 try_inject_alloc_failure();
2354 VM_ShenandoahFinalUpdateRefs op;
2355 VMThread::execute(&op);
2356 }
2357
2358 void ShenandoahHeap::vmop_entry_init_traversal() {
2359 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2360 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2361 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2362
2363 try_inject_alloc_failure();
2364 VM_ShenandoahInitTraversalGC op;
2365 VMThread::execute(&op);
2366 }
2367
2368 void ShenandoahHeap::vmop_entry_final_traversal() {
2369 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2370 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2371 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2372
2373 try_inject_alloc_failure();
2374 VM_ShenandoahFinalTraversalGC op;
2375 VMThread::execute(&op);
2376 }
2377
2378 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2379 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2380 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2381 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2382
2383 try_inject_alloc_failure();
2384 VM_ShenandoahFullGC op(cause);
2385 VMThread::execute(&op);
2386 }
2387
2388 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2389 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2390 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2391 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2392
2393 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2394 VMThread::execute(°enerated_gc);
2395 }
2396
2397 void ShenandoahHeap::entry_init_mark() {
2398 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2399 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2400 const char* msg = init_mark_event_message();
2401 GCTraceTime(Info, gc) time(msg, gc_timer());
2402 EventMark em("%s", msg);
2403
2404 ShenandoahWorkerScope scope(workers(),
2405 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2406 "init marking");
2407
2408 op_init_mark();
2409 }
2410
2411 void ShenandoahHeap::entry_final_mark() {
2412 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2413 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2414 const char* msg = final_mark_event_message();
2415 GCTraceTime(Info, gc) time(msg, gc_timer());
2416 EventMark em("%s", msg);
2417
2418 ShenandoahWorkerScope scope(workers(),
2419 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2420 "final marking");
2421
2422 op_final_mark();
2423 }
2424
2425 void ShenandoahHeap::entry_final_evac() {
2426 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2427 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2428 static const char* msg = "Pause Final Evac";
2429 GCTraceTime(Info, gc) time(msg, gc_timer());
2430 EventMark em("%s", msg);
2431
2432 op_final_evac();
2433 }
2434
2435 void ShenandoahHeap::entry_init_updaterefs() {
2436 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2437 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2438
2439 static const char* msg = "Pause Init Update Refs";
2440 GCTraceTime(Info, gc) time(msg, gc_timer());
2441 EventMark em("%s", msg);
2442
2443 // No workers used in this phase, no setup required
2444
2445 op_init_updaterefs();
2446 }
2447
2448 void ShenandoahHeap::entry_final_updaterefs() {
2449 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2450 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2451
2452 static const char* msg = "Pause Final Update Refs";
2453 GCTraceTime(Info, gc) time(msg, gc_timer());
2454 EventMark em("%s", msg);
2455
2456 ShenandoahWorkerScope scope(workers(),
2457 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2458 "final reference update");
2459
2460 op_final_updaterefs();
2461 }
2462
2463 void ShenandoahHeap::entry_init_traversal() {
2464 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2465 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2466
2467 static const char* msg = "Pause Init Traversal";
2468 GCTraceTime(Info, gc) time(msg, gc_timer());
2469 EventMark em("%s", msg);
2470
2471 ShenandoahWorkerScope scope(workers(),
2472 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2473 "init traversal");
2474
2475 op_init_traversal();
2476 }
2477
2478 void ShenandoahHeap::entry_final_traversal() {
2479 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2480 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2481
2482 static const char* msg = "Pause Final Traversal";
2483 GCTraceTime(Info, gc) time(msg, gc_timer());
2484 EventMark em("%s", msg);
2485
2486 ShenandoahWorkerScope scope(workers(),
2487 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2488 "final traversal");
2489
2490 op_final_traversal();
2491 }
2492
2493 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2494 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2495 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2496
2497 static const char* msg = "Pause Full";
2498 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2499 EventMark em("%s", msg);
2500
2501 ShenandoahWorkerScope scope(workers(),
2502 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2503 "full gc");
2504
2505 op_full(cause);
2506 }
2507
2508 void ShenandoahHeap::entry_degenerated(int point) {
2509 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2510 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2511
2512 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2513 const char* msg = degen_event_message(dpoint);
2514 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2515 EventMark em("%s", msg);
2516
2517 ShenandoahWorkerScope scope(workers(),
2518 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2519 "stw degenerated gc");
2520
2521 set_degenerated_gc_in_progress(true);
2522 op_degenerated(dpoint);
2523 set_degenerated_gc_in_progress(false);
2524 }
2525
2526 void ShenandoahHeap::entry_mark() {
2527 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2528
2529 const char* msg = conc_mark_event_message();
2530 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2531 EventMark em("%s", msg);
2532
2533 ShenandoahWorkerScope scope(workers(),
2534 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2535 "concurrent marking");
2536
2537 try_inject_alloc_failure();
2538 op_mark();
2539 }
2540
2541 void ShenandoahHeap::entry_evac() {
2542 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2543 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2544
2545 static const char* msg = "Concurrent evacuation";
2546 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2547 EventMark em("%s", msg);
2548
2549 ShenandoahWorkerScope scope(workers(),
2550 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2551 "concurrent evacuation");
2552
2553 try_inject_alloc_failure();
2554 op_conc_evac();
2555 }
2556
2557 void ShenandoahHeap::entry_updaterefs() {
2558 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2559
2560 static const char* msg = "Concurrent update references";
2561 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2562 EventMark em("%s", msg);
2563
2564 ShenandoahWorkerScope scope(workers(),
2565 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2566 "concurrent reference update");
2567
2568 try_inject_alloc_failure();
2569 op_updaterefs();
2570 }
2571 void ShenandoahHeap::entry_cleanup() {
2572 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2573
2574 static const char* msg = "Concurrent cleanup";
2575 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2576 EventMark em("%s", msg);
2577
2578 // This phase does not use workers, no need for setup
2579
2580 try_inject_alloc_failure();
2581 op_cleanup();
2582 }
2583
2584 void ShenandoahHeap::entry_reset() {
2585 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2586
2587 static const char* msg = "Concurrent reset";
2588 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2589 EventMark em("%s", msg);
2590
2591 ShenandoahWorkerScope scope(workers(),
2592 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2593 "concurrent reset");
2594
2595 try_inject_alloc_failure();
2596 op_reset();
2597 }
2598
2599 void ShenandoahHeap::entry_preclean() {
2600 if (ShenandoahPreclean && process_references()) {
2601 static const char* msg = "Concurrent precleaning";
2602 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2603 EventMark em("%s", msg);
2604
2605 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2606
2607 ShenandoahWorkerScope scope(workers(),
2608 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2609 "concurrent preclean",
2610 /* check_workers = */ false);
2611
2612 try_inject_alloc_failure();
2613 op_preclean();
2614 }
2615 }
2616
2617 void ShenandoahHeap::entry_traversal() {
2618 static const char* msg = "Concurrent traversal";
2619 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2620 EventMark em("%s", msg);
2621
2622 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2623
2624 ShenandoahWorkerScope scope(workers(),
2625 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2626 "concurrent traversal");
2627
2628 try_inject_alloc_failure();
2629 op_traversal();
2630 }
2631
2632 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2633 static const char *msg = "Concurrent uncommit";
2634 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2635 EventMark em("%s", msg);
2636
2637 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2638
2639 op_uncommit(shrink_before);
2640 }
2641
2642 void ShenandoahHeap::try_inject_alloc_failure() {
2643 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2644 _inject_alloc_failure.set();
2645 os::naked_short_sleep(1);
2646 if (cancelled_gc()) {
2647 log_info(gc)("Allocation failure was successfully injected");
2648 }
2649 }
2650 }
2651
2652 bool ShenandoahHeap::should_inject_alloc_failure() {
2653 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2654 }
2655
2656 void ShenandoahHeap::initialize_serviceability() {
2657 _memory_pool = new ShenandoahMemoryPool(this);
2658 _cycle_memory_manager.add_pool(_memory_pool);
2659 _stw_memory_manager.add_pool(_memory_pool);
2660 }
2661
2662 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2663 GrowableArray<GCMemoryManager*> memory_managers(2);
2664 memory_managers.append(&_cycle_memory_manager);
2665 memory_managers.append(&_stw_memory_manager);
2666 return memory_managers;
2667 }
2668
2669 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2670 GrowableArray<MemoryPool*> memory_pools(1);
2671 memory_pools.append(_memory_pool);
2672 return memory_pools;
2673 }
2674
2675 MemoryUsage ShenandoahHeap::memory_usage() {
2676 return _memory_pool->get_memory_usage();
2677 }
2678
2679 void ShenandoahHeap::enter_evacuation() {
2680 _oom_evac_handler.enter_evacuation();
2681 }
2682
2683 void ShenandoahHeap::leave_evacuation() {
2684 _oom_evac_handler.leave_evacuation();
2685 }
2686
2687 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2688 _heap(ShenandoahHeap::heap()),
2689 _index(0) {}
2690
2691 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2692 _heap(heap),
2693 _index(0) {}
2694
2695 void ShenandoahRegionIterator::reset() {
2696 _index = 0;
2697 }
2698
2699 bool ShenandoahRegionIterator::has_next() const {
2700 return _index < _heap->num_regions();
2701 }
2702
2703 char ShenandoahHeap::gc_state() const {
2704 return _gc_state.raw_value();
2705 }
2706
2707 void ShenandoahHeap::deduplicate_string(oop str) {
2708 assert(java_lang_String::is_instance(str), "invariant");
2709
2710 if (ShenandoahStringDedup::is_enabled()) {
2711 ShenandoahStringDedup::deduplicate(str);
2712 }
2713 }
2714
2715 const char* ShenandoahHeap::init_mark_event_message() const {
2716 bool update_refs = has_forwarded_objects();
2717 bool proc_refs = process_references();
2718 bool unload_cls = unload_classes();
2719
2720 if (update_refs && proc_refs && unload_cls) {
2721 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2722 } else if (update_refs && proc_refs) {
2723 return "Pause Init Mark (update refs) (process weakrefs)";
2724 } else if (update_refs && unload_cls) {
2725 return "Pause Init Mark (update refs) (unload classes)";
2726 } else if (proc_refs && unload_cls) {
2727 return "Pause Init Mark (process weakrefs) (unload classes)";
2728 } else if (update_refs) {
2729 return "Pause Init Mark (update refs)";
2730 } else if (proc_refs) {
2731 return "Pause Init Mark (process weakrefs)";
2732 } else if (unload_cls) {
2733 return "Pause Init Mark (unload classes)";
2734 } else {
2735 return "Pause Init Mark";
2736 }
2737 }
2738
2739 const char* ShenandoahHeap::final_mark_event_message() const {
2740 bool update_refs = has_forwarded_objects();
2741 bool proc_refs = process_references();
2742 bool unload_cls = unload_classes();
2743
2744 if (update_refs && proc_refs && unload_cls) {
2745 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2746 } else if (update_refs && proc_refs) {
2747 return "Pause Final Mark (update refs) (process weakrefs)";
2748 } else if (update_refs && unload_cls) {
2749 return "Pause Final Mark (update refs) (unload classes)";
2750 } else if (proc_refs && unload_cls) {
2751 return "Pause Final Mark (process weakrefs) (unload classes)";
2752 } else if (update_refs) {
2753 return "Pause Final Mark (update refs)";
2754 } else if (proc_refs) {
2755 return "Pause Final Mark (process weakrefs)";
2756 } else if (unload_cls) {
2757 return "Pause Final Mark (unload classes)";
2758 } else {
2759 return "Pause Final Mark";
2760 }
2761 }
2762
2763 const char* ShenandoahHeap::conc_mark_event_message() const {
2764 bool update_refs = has_forwarded_objects();
2765 bool proc_refs = process_references();
2766 bool unload_cls = unload_classes();
2767
2768 if (update_refs && proc_refs && unload_cls) {
2769 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2770 } else if (update_refs && proc_refs) {
2771 return "Concurrent marking (update refs) (process weakrefs)";
2772 } else if (update_refs && unload_cls) {
2773 return "Concurrent marking (update refs) (unload classes)";
2774 } else if (proc_refs && unload_cls) {
2775 return "Concurrent marking (process weakrefs) (unload classes)";
2776 } else if (update_refs) {
2777 return "Concurrent marking (update refs)";
2778 } else if (proc_refs) {
2779 return "Concurrent marking (process weakrefs)";
2780 } else if (unload_cls) {
2781 return "Concurrent marking (unload classes)";
2782 } else {
2783 return "Concurrent marking";
2784 }
2785 }
2786
2787 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2788 switch (point) {
2789 case _degenerated_unset:
2790 return "Pause Degenerated GC (<UNSET>)";
2791 case _degenerated_traversal:
2792 return "Pause Degenerated GC (Traversal)";
2793 case _degenerated_outside_cycle:
2794 return "Pause Degenerated GC (Outside of Cycle)";
2795 case _degenerated_mark:
2796 return "Pause Degenerated GC (Mark)";
2797 case _degenerated_evac:
2798 return "Pause Degenerated GC (Evacuation)";
2799 case _degenerated_updaterefs:
2800 return "Pause Degenerated GC (Update Refs)";
2801 default:
2802 ShouldNotReachHere();
2803 return "ERROR";
2804 }
2805 }
2806
2807 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2808 #ifdef ASSERT
2809 assert(_liveness_cache != NULL, "sanity");
2810 assert(worker_id < _max_workers, "sanity");
2811 for (uint i = 0; i < num_regions(); i++) {
2812 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2813 }
2814 #endif
2815 return _liveness_cache[worker_id];
2816 }
2817
2818 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2819 assert(worker_id < _max_workers, "sanity");
2820 assert(_liveness_cache != NULL, "sanity");
2821 jushort* ld = _liveness_cache[worker_id];
2822 for (uint i = 0; i < num_regions(); i++) {
2823 ShenandoahHeapRegion* r = get_region(i);
2824 jushort live = ld[i];
2825 if (live > 0) {
2826 r->increase_live_data_gc_words(live);
2827 ld[i] = 0;
2828 }
2829 }
2830 }
2831
2832 size_t ShenandoahHeap::obj_size(oop obj) const {
2833 return CollectedHeap::obj_size(obj) + ShenandoahForwarding::word_size();
2834 }
2835
2836 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2837 return ShenandoahForwarding::byte_size();
2838 }