1 /*
2 * Copyright (c) 2013, 2020, Red Hat, Inc. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "memory/allocation.hpp"
27 #include "memory/universe.hpp"
28
29 #include "gc/shared/gcArguments.hpp"
30 #include "gc/shared/gcTimer.hpp"
31 #include "gc/shared/gcTraceTime.inline.hpp"
32 #include "gc/shared/locationPrinter.inline.hpp"
33 #include "gc/shared/memAllocator.hpp"
34 #include "gc/shared/oopStorageSet.hpp"
35 #include "gc/shared/plab.hpp"
36
37 #include "gc/shenandoah/shenandoahBarrierSet.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/shenandoahConcurrentRoots.hpp"
43 #include "gc/shenandoah/shenandoahControlThread.hpp"
44 #include "gc/shenandoah/shenandoahFreeSet.hpp"
45 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
46 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
47 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
48 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
49 #include "gc/shenandoah/shenandoahIUMode.hpp"
50 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
51 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
52 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
53 #include "gc/shenandoah/shenandoahMetrics.hpp"
54 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
55 #include "gc/shenandoah/shenandoahNormalMode.hpp"
56 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
57 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
58 #include "gc/shenandoah/shenandoahPadding.hpp"
59 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp"
60 #include "gc/shenandoah/shenandoahPassiveMode.hpp"
61 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
62 #include "gc/shenandoah/shenandoahStringDedup.hpp"
63 #include "gc/shenandoah/shenandoahTaskqueue.hpp"
64 #include "gc/shenandoah/shenandoahTraversalMode.hpp"
65 #include "gc/shenandoah/shenandoahUtils.hpp"
66 #include "gc/shenandoah/shenandoahVerifier.hpp"
67 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
68 #include "gc/shenandoah/shenandoahVMOperations.hpp"
69 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
70 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
71 #if INCLUDE_JFR
72 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
73 #endif
74
75 #include "memory/metaspace.hpp"
76 #include "oops/compressedOops.inline.hpp"
77 #include "runtime/atomic.hpp"
78 #include "runtime/globals.hpp"
79 #include "runtime/interfaceSupport.inline.hpp"
80 #include "runtime/orderAccess.hpp"
81 #include "runtime/safepointMechanism.hpp"
82 #include "runtime/vmThread.hpp"
83 #include "services/mallocTracker.hpp"
84 #include "utilities/powerOfTwo.hpp"
85
86 ShenandoahHeap* ShenandoahHeap::_heap = NULL;
87
88 #ifdef ASSERT
89 template <class T>
90 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
91 T o = RawAccess<>::oop_load(p);
92 if (! CompressedOops::is_null(o)) {
93 oop obj = CompressedOops::decode_not_null(o);
94 shenandoah_assert_not_forwarded(p, obj);
95 }
96 }
97
98 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
99 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
100 #endif
101
102 class ShenandoahPretouchHeapTask : public AbstractGangTask {
103 private:
104 ShenandoahRegionIterator _regions;
105 const size_t _page_size;
106 public:
107 ShenandoahPretouchHeapTask(size_t page_size) :
108 AbstractGangTask("Shenandoah Pretouch Heap"),
109 _page_size(page_size) {}
110
111 virtual void work(uint worker_id) {
112 ShenandoahHeapRegion* r = _regions.next();
113 while (r != NULL) {
114 os::pretouch_memory(r->bottom(), r->end(), _page_size);
115 r = _regions.next();
116 }
117 }
118 };
119
120 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
121 private:
122 ShenandoahRegionIterator _regions;
123 char* _bitmap_base;
124 const size_t _bitmap_size;
125 const size_t _page_size;
126 public:
127 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
128 AbstractGangTask("Shenandoah Pretouch Bitmap"),
129 _bitmap_base(bitmap_base),
130 _bitmap_size(bitmap_size),
131 _page_size(page_size) {}
132
133 virtual void work(uint worker_id) {
134 ShenandoahHeapRegion* r = _regions.next();
135 while (r != NULL) {
136 size_t start = r->index() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
137 size_t end = (r->index() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
138 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
139
140 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
141
142 r = _regions.next();
143 }
144 }
145 };
146
147 jint ShenandoahHeap::initialize() {
148 initialize_heuristics();
149
150 //
151 // Figure out heap sizing
152 //
153
154 size_t init_byte_size = InitialHeapSize;
155 size_t min_byte_size = MinHeapSize;
156 size_t max_byte_size = MaxHeapSize;
157 size_t heap_alignment = HeapAlignment;
158
159 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
160
161 if (ShenandoahAlwaysPreTouch) {
162 // Enabled pre-touch means the entire heap is committed right away.
163 init_byte_size = max_byte_size;
164 }
165
166 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
167 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
168
169 _num_regions = ShenandoahHeapRegion::region_count();
170
171 size_t num_committed_regions = init_byte_size / reg_size_bytes;
172 num_committed_regions = MIN2(num_committed_regions, _num_regions);
173 assert(num_committed_regions <= _num_regions, "sanity");
174 _initial_size = num_committed_regions * reg_size_bytes;
175
176 size_t num_min_regions = min_byte_size / reg_size_bytes;
177 num_min_regions = MIN2(num_min_regions, _num_regions);
178 assert(num_min_regions <= _num_regions, "sanity");
179 _minimum_size = num_min_regions * reg_size_bytes;
180
181 _committed = _initial_size;
182
183 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
184 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
185 size_t region_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
186
187 //
188 // Reserve and commit memory for heap
189 //
190
191 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
192 initialize_reserved_region(heap_rs);
193 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
194 _heap_region_special = heap_rs.special();
195
196 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
197 "Misaligned heap: " PTR_FORMAT, p2i(base()));
198
199 #if SHENANDOAH_OPTIMIZED_OBJTASK
200 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits.
201 // Fail if we ever attempt to address more than we can.
202 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) {
203 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n"
204 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n"
205 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).",
206 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable());
207 vm_exit_during_initialization("Fatal Error", buf);
208 }
209 #endif
210
211 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
212 if (!_heap_region_special) {
213 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
214 "Cannot commit heap memory");
215 }
216
217 //
218 // Reserve and commit memory for bitmap(s)
219 //
220
221 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
222 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
223
224 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
225
226 guarantee(bitmap_bytes_per_region != 0,
227 "Bitmap bytes per region should not be zero");
228 guarantee(is_power_of_2(bitmap_bytes_per_region),
229 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
230
231 if (bitmap_page_size > bitmap_bytes_per_region) {
232 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
233 _bitmap_bytes_per_slice = bitmap_page_size;
234 } else {
235 _bitmap_regions_per_slice = 1;
236 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
237 }
238
239 guarantee(_bitmap_regions_per_slice >= 1,
240 "Should have at least one region per slice: " SIZE_FORMAT,
241 _bitmap_regions_per_slice);
242
243 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
244 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
245 _bitmap_bytes_per_slice, bitmap_page_size);
246
247 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
248 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
249 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
250 _bitmap_region_special = bitmap.special();
251
252 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
253 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
254 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
255 if (!_bitmap_region_special) {
256 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
257 "Cannot commit bitmap memory");
258 }
259
260 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
261
262 if (ShenandoahVerify) {
263 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
264 if (!verify_bitmap.special()) {
265 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
266 "Cannot commit verification bitmap memory");
267 }
268 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
269 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
270 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
271 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
272 }
273
274 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
275 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
276 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
277 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
278 _aux_bitmap_region_special = aux_bitmap.special();
279 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
280
281 //
282 // Create regions and region sets
283 //
284 size_t region_align = align_up(sizeof(ShenandoahHeapRegion), SHENANDOAH_CACHE_LINE_SIZE);
285 size_t region_storage_size = align_up(region_align * _num_regions, region_page_size);
286
287 ReservedSpace region_storage(region_storage_size, region_page_size);
288 MemTracker::record_virtual_memory_type(region_storage.base(), mtGC);
289 if (!region_storage.special()) {
290 os::commit_memory_or_exit(region_storage.base(), region_storage_size, region_page_size, false,
291 "Cannot commit region memory");
292 }
293
294 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
295 _free_set = new ShenandoahFreeSet(this, _num_regions);
296 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
297
298 {
299 ShenandoahHeapLocker locker(lock());
300
301 for (size_t i = 0; i < _num_regions; i++) {
302 HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i;
303 bool is_committed = i < num_committed_regions;
304 void* loc = region_storage.base() + i * region_align;
305
306 ShenandoahHeapRegion* r = new (loc) ShenandoahHeapRegion(start, i, is_committed);
307 assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity");
308
309 _marking_context->initialize_top_at_mark_start(r);
310 _regions[i] = r;
311 assert(!collection_set()->is_in(i), "New region should not be in collection set");
312 }
313
314 // Initialize to complete
315 _marking_context->mark_complete();
316
317 _free_set->rebuild();
318 }
319
320 if (ShenandoahAlwaysPreTouch) {
321 assert(!AlwaysPreTouch, "Should have been overridden");
322
323 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
324 // before initialize() below zeroes it with initializing thread. For any given region,
325 // we touch the region and the corresponding bitmaps from the same thread.
326 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
327
328 size_t pretouch_heap_page_size = heap_page_size;
329 size_t pretouch_bitmap_page_size = bitmap_page_size;
330
331 #ifdef LINUX
332 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
333 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
334 // them into huge one. Therefore, we need to pretouch with smaller pages.
335 if (UseTransparentHugePages) {
336 pretouch_heap_page_size = (size_t)os::vm_page_size();
337 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
338 }
339 #endif
340
341 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
342 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
343
344 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
345 _num_regions, pretouch_bitmap_page_size);
346 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
347 _workers->run_task(&bcl);
348
349 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
350 _num_regions, pretouch_heap_page_size);
351 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
352 _workers->run_task(&hcl);
353 }
354
355 //
356 // Initialize the rest of GC subsystems
357 //
358
359 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
360 for (uint worker = 0; worker < _max_workers; worker++) {
361 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
362 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
363 }
364
365 // There should probably be Shenandoah-specific options for these,
366 // just as there are G1-specific options.
367 {
368 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set();
369 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold
370 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent
371 }
372
373 _monitoring_support = new ShenandoahMonitoringSupport(this);
374 _phase_timings = new ShenandoahPhaseTimings();
375 ShenandoahStringDedup::initialize();
376 ShenandoahCodeRoots::initialize();
377
378 if (ShenandoahPacing) {
379 _pacer = new ShenandoahPacer(this);
380 _pacer->setup_for_idle();
381 } else {
382 _pacer = NULL;
383 }
384
385 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ?
386 new ShenandoahTraversalGC(this) :
387 NULL;
388 _control_thread = new ShenandoahControlThread();
389
390 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
391 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
392 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
393 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
394 );
395
396 log_info(gc, init)("Safepointing mechanism: thread-local poll");
397
398 return JNI_OK;
399 }
400
401 void ShenandoahHeap::initialize_heuristics() {
402 if (ShenandoahGCMode != NULL) {
403 if (strcmp(ShenandoahGCMode, "traversal") == 0) {
404 _gc_mode = new ShenandoahTraversalMode();
405 } else if (strcmp(ShenandoahGCMode, "normal") == 0) {
406 _gc_mode = new ShenandoahNormalMode();
407 } else if (strcmp(ShenandoahGCMode, "iu") == 0) {
408 _gc_mode = new ShenandoahIUMode();
409 } else if (strcmp(ShenandoahGCMode, "passive") == 0) {
410 _gc_mode = new ShenandoahPassiveMode();
411 } else {
412 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option");
413 }
414 } else {
415 ShouldNotReachHere();
416 }
417 _gc_mode->initialize_flags();
418 _heuristics = _gc_mode->initialize_heuristics();
419
420 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
421 vm_exit_during_initialization(
422 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
423 _heuristics->name()));
424 }
425 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
426 vm_exit_during_initialization(
427 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
428 _heuristics->name()));
429 }
430 log_info(gc, init)("Shenandoah heuristics: %s",
431 _heuristics->name());
432 }
433
434 #ifdef _MSC_VER
435 #pragma warning( push )
436 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
437 #endif
438
439 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
440 CollectedHeap(),
441 _initial_size(0),
442 _used(0),
443 _committed(0),
444 _bytes_allocated_since_gc_start(0),
445 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
446 _workers(NULL),
447 _safepoint_workers(NULL),
448 _heap_region_special(false),
449 _num_regions(0),
450 _regions(NULL),
451 _update_refs_iterator(this),
452 _control_thread(NULL),
453 _shenandoah_policy(policy),
454 _heuristics(NULL),
455 _free_set(NULL),
456 _scm(new ShenandoahConcurrentMark()),
457 _traversal_gc(NULL),
458 _full_gc(new ShenandoahMarkCompact()),
459 _pacer(NULL),
460 _verifier(NULL),
461 _phase_timings(NULL),
462 _monitoring_support(NULL),
463 _memory_pool(NULL),
464 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
465 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
466 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
467 _soft_ref_policy(),
468 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
469 _ref_processor(NULL),
470 _marking_context(NULL),
471 _bitmap_size(0),
472 _bitmap_regions_per_slice(0),
473 _bitmap_bytes_per_slice(0),
474 _bitmap_region_special(false),
475 _aux_bitmap_region_special(false),
476 _liveness_cache(NULL),
477 _collection_set(NULL)
478 {
479 _heap = this;
480
481 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
482 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
483
484 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
485
486 _max_workers = MAX2(_max_workers, 1U);
487 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
488 /* are_GC_task_threads */ true,
489 /* are_ConcurrentGC_threads */ true);
490 if (_workers == NULL) {
491 vm_exit_during_initialization("Failed necessary allocation.");
492 } else {
493 _workers->initialize_workers();
494 }
495
496 if (ParallelGCThreads > 1) {
497 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
498 ParallelGCThreads,
499 /* are_GC_task_threads */ false,
500 /* are_ConcurrentGC_threads */ false);
501 _safepoint_workers->initialize_workers();
502 }
503 }
504
505 #ifdef _MSC_VER
506 #pragma warning( pop )
507 #endif
508
509 class ShenandoahResetBitmapTask : public AbstractGangTask {
510 private:
511 ShenandoahRegionIterator _regions;
512
513 public:
514 ShenandoahResetBitmapTask() :
515 AbstractGangTask("Parallel Reset Bitmap Task") {}
516
517 void work(uint worker_id) {
518 ShenandoahHeapRegion* region = _regions.next();
519 ShenandoahHeap* heap = ShenandoahHeap::heap();
520 ShenandoahMarkingContext* const ctx = heap->marking_context();
521 while (region != NULL) {
522 if (heap->is_bitmap_slice_committed(region)) {
523 ctx->clear_bitmap(region);
524 }
525 region = _regions.next();
526 }
527 }
528 };
529
530 void ShenandoahHeap::reset_mark_bitmap() {
531 assert_gc_workers(_workers->active_workers());
532 mark_incomplete_marking_context();
533
534 ShenandoahResetBitmapTask task;
535 _workers->run_task(&task);
536 }
537
538 void ShenandoahHeap::print_on(outputStream* st) const {
539 st->print_cr("Shenandoah Heap");
540 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used",
541 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()),
542 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()),
543 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used()));
544 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions",
545 num_regions(),
546 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()),
547 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes()));
548
549 st->print("Status: ");
550 if (has_forwarded_objects()) st->print("has forwarded objects, ");
551 if (is_concurrent_mark_in_progress()) st->print("marking, ");
552 if (is_evacuation_in_progress()) st->print("evacuating, ");
553 if (is_update_refs_in_progress()) st->print("updating refs, ");
554 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
555 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
556 if (is_full_gc_in_progress()) st->print("full gc, ");
557 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
558 if (is_concurrent_root_in_progress()) st->print("concurrent roots, ");
559
560 if (cancelled_gc()) {
561 st->print("cancelled");
562 } else {
563 st->print("not cancelled");
564 }
565 st->cr();
566
567 st->print_cr("Reserved region:");
568 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
569 p2i(reserved_region().start()),
570 p2i(reserved_region().end()));
571
572 ShenandoahCollectionSet* cset = collection_set();
573 st->print_cr("Collection set:");
574 if (cset != NULL) {
575 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
576 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
577 } else {
578 st->print_cr(" (NULL)");
579 }
580
581 st->cr();
582 MetaspaceUtils::print_on(st);
583
584 if (Verbose) {
585 print_heap_regions_on(st);
586 }
587 }
588
589 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
590 public:
591 void do_thread(Thread* thread) {
592 assert(thread != NULL, "Sanity");
593 assert(thread->is_Worker_thread(), "Only worker thread expected");
594 ShenandoahThreadLocalData::initialize_gclab(thread);
595 }
596 };
597
598 void ShenandoahHeap::post_initialize() {
599 CollectedHeap::post_initialize();
600 MutexLocker ml(Threads_lock);
601
602 ShenandoahInitWorkerGCLABClosure init_gclabs;
603 _workers->threads_do(&init_gclabs);
604
605 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
606 // Now, we will let WorkGang to initialize gclab when new worker is created.
607 _workers->set_initialize_gclab();
608
609 _scm->initialize(_max_workers);
610 _full_gc->initialize(_gc_timer);
611
612 ref_processing_init();
613
614 _heuristics->initialize();
615
616 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers());
617 }
618
619 size_t ShenandoahHeap::used() const {
620 return Atomic::load_acquire(&_used);
621 }
622
623 size_t ShenandoahHeap::committed() const {
624 OrderAccess::acquire();
625 return _committed;
626 }
627
628 void ShenandoahHeap::increase_committed(size_t bytes) {
629 shenandoah_assert_heaplocked_or_safepoint();
630 _committed += bytes;
631 }
632
633 void ShenandoahHeap::decrease_committed(size_t bytes) {
634 shenandoah_assert_heaplocked_or_safepoint();
635 _committed -= bytes;
636 }
637
638 void ShenandoahHeap::increase_used(size_t bytes) {
639 Atomic::add(&_used, bytes);
640 }
641
642 void ShenandoahHeap::set_used(size_t bytes) {
643 Atomic::release_store_fence(&_used, bytes);
644 }
645
646 void ShenandoahHeap::decrease_used(size_t bytes) {
647 assert(used() >= bytes, "never decrease heap size by more than we've left");
648 Atomic::sub(&_used, bytes);
649 }
650
651 void ShenandoahHeap::increase_allocated(size_t bytes) {
652 Atomic::add(&_bytes_allocated_since_gc_start, bytes);
653 }
654
655 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
656 size_t bytes = words * HeapWordSize;
657 if (!waste) {
658 increase_used(bytes);
659 }
660 increase_allocated(bytes);
661 if (ShenandoahPacing) {
662 control_thread()->pacing_notify_alloc(words);
663 if (waste) {
664 pacer()->claim_for_alloc(words, true);
665 }
666 }
667 }
668
669 size_t ShenandoahHeap::capacity() const {
670 return committed();
671 }
672
673 size_t ShenandoahHeap::max_capacity() const {
674 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
675 }
676
677 size_t ShenandoahHeap::min_capacity() const {
678 return _minimum_size;
679 }
680
681 size_t ShenandoahHeap::initial_capacity() const {
682 return _initial_size;
683 }
684
685 bool ShenandoahHeap::is_in(const void* p) const {
686 HeapWord* heap_base = (HeapWord*) base();
687 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
688 return p >= heap_base && p < last_region_end;
689 }
690
691 void ShenandoahHeap::op_uncommit(double shrink_before) {
692 assert (ShenandoahUncommit, "should be enabled");
693
694 // Application allocates from the beginning of the heap, and GC allocates at
695 // the end of it. It is more efficient to uncommit from the end, so that applications
696 // could enjoy the near committed regions. GC allocations are much less frequent,
697 // and therefore can accept the committing costs.
698
699 size_t count = 0;
700 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
701 ShenandoahHeapRegion* r = get_region(i - 1);
702 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
703 ShenandoahHeapLocker locker(lock());
704 if (r->is_empty_committed()) {
705 // Do not uncommit below minimal capacity
706 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
707 break;
708 }
709
710 r->make_uncommitted();
711 count++;
712 }
713 }
714 SpinPause(); // allow allocators to take the lock
715 }
716
717 if (count > 0) {
718 control_thread()->notify_heap_changed();
719 }
720 }
721
722 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
723 // New object should fit the GCLAB size
724 size_t min_size = MAX2(size, PLAB::min_size());
725
726 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
727 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
728 new_size = MIN2(new_size, PLAB::max_size());
729 new_size = MAX2(new_size, PLAB::min_size());
730
731 // Record new heuristic value even if we take any shortcut. This captures
732 // the case when moderately-sized objects always take a shortcut. At some point,
733 // heuristics should catch up with them.
734 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
735
736 if (new_size < size) {
737 // New size still does not fit the object. Fall back to shared allocation.
738 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
739 return NULL;
740 }
741
742 // Retire current GCLAB, and allocate a new one.
743 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
744 gclab->retire();
745
746 size_t actual_size = 0;
747 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
748 if (gclab_buf == NULL) {
749 return NULL;
750 }
751
752 assert (size <= actual_size, "allocation should fit");
753
754 if (ZeroTLAB) {
755 // ..and clear it.
756 Copy::zero_to_words(gclab_buf, actual_size);
757 } else {
758 // ...and zap just allocated object.
759 #ifdef ASSERT
760 // Skip mangling the space corresponding to the object header to
761 // ensure that the returned space is not considered parsable by
762 // any concurrent GC thread.
763 size_t hdr_size = oopDesc::header_size();
764 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
765 #endif // ASSERT
766 }
767 gclab->set_buf(gclab_buf, actual_size);
768 return gclab->allocate(size);
769 }
770
771 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
772 size_t requested_size,
773 size_t* actual_size) {
774 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
775 HeapWord* res = allocate_memory(req);
776 if (res != NULL) {
777 *actual_size = req.actual_size();
778 } else {
779 *actual_size = 0;
780 }
781 return res;
782 }
783
784 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
785 size_t word_size,
786 size_t* actual_size) {
787 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
788 HeapWord* res = allocate_memory(req);
789 if (res != NULL) {
790 *actual_size = req.actual_size();
791 } else {
792 *actual_size = 0;
793 }
794 return res;
795 }
796
797 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
798 intptr_t pacer_epoch = 0;
799 bool in_new_region = false;
800 HeapWord* result = NULL;
801
802 if (req.is_mutator_alloc()) {
803 if (ShenandoahPacing) {
804 pacer()->pace_for_alloc(req.size());
805 pacer_epoch = pacer()->epoch();
806 }
807
808 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
809 result = allocate_memory_under_lock(req, in_new_region);
810 }
811
812 // Allocation failed, block until control thread reacted, then retry allocation.
813 //
814 // It might happen that one of the threads requesting allocation would unblock
815 // way later after GC happened, only to fail the second allocation, because
816 // other threads have already depleted the free storage. In this case, a better
817 // strategy is to try again, as long as GC makes progress.
818 //
819 // Then, we need to make sure the allocation was retried after at least one
820 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
821
822 size_t tries = 0;
823
824 while (result == NULL && _progress_last_gc.is_set()) {
825 tries++;
826 control_thread()->handle_alloc_failure(req.size());
827 result = allocate_memory_under_lock(req, in_new_region);
828 }
829
830 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
831 tries++;
832 control_thread()->handle_alloc_failure(req.size());
833 result = allocate_memory_under_lock(req, in_new_region);
834 }
835
836 } else {
837 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
838 result = allocate_memory_under_lock(req, in_new_region);
839 // Do not call handle_alloc_failure() here, because we cannot block.
840 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
841 }
842
843 if (in_new_region) {
844 control_thread()->notify_heap_changed();
845 }
846
847 if (result != NULL) {
848 size_t requested = req.size();
849 size_t actual = req.actual_size();
850
851 assert (req.is_lab_alloc() || (requested == actual),
852 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
853 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
854
855 if (req.is_mutator_alloc()) {
856 notify_mutator_alloc_words(actual, false);
857
858 // If we requested more than we were granted, give the rest back to pacer.
859 // This only matters if we are in the same pacing epoch: do not try to unpace
860 // over the budget for the other phase.
861 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
862 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
863 }
864 } else {
865 increase_used(actual*HeapWordSize);
866 }
867 }
868
869 return result;
870 }
871
872 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
873 ShenandoahHeapLocker locker(lock());
874 return _free_set->allocate(req, in_new_region);
875 }
876
877 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
878 bool* gc_overhead_limit_was_exceeded) {
879 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
880 return allocate_memory(req);
881 }
882
883 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
884 size_t size,
885 Metaspace::MetadataType mdtype) {
886 MetaWord* result;
887
888 // Inform metaspace OOM to GC heuristics if class unloading is possible.
889 if (heuristics()->can_unload_classes()) {
890 ShenandoahHeuristics* h = heuristics();
891 h->record_metaspace_oom();
892 }
893
894 // Expand and retry allocation
895 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
896 if (result != NULL) {
897 return result;
898 }
899
900 // Start full GC
901 collect(GCCause::_metadata_GC_clear_soft_refs);
902
903 // Retry allocation
904 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
905 if (result != NULL) {
906 return result;
907 }
908
909 // Expand and retry allocation
910 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
911 if (result != NULL) {
912 return result;
913 }
914
915 // Out of memory
916 return NULL;
917 }
918
919 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
920 private:
921 ShenandoahHeap* const _heap;
922 Thread* const _thread;
923 public:
924 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
925 _heap(heap), _thread(Thread::current()) {}
926
927 void do_object(oop p) {
928 shenandoah_assert_marked(NULL, p);
929 if (!p->is_forwarded()) {
930 _heap->evacuate_object(p, _thread);
931 }
932 }
933 };
934
935 class ShenandoahEvacuationTask : public AbstractGangTask {
936 private:
937 ShenandoahHeap* const _sh;
938 ShenandoahCollectionSet* const _cs;
939 bool _concurrent;
940 public:
941 ShenandoahEvacuationTask(ShenandoahHeap* sh,
942 ShenandoahCollectionSet* cs,
943 bool concurrent) :
944 AbstractGangTask("Parallel Evacuation Task"),
945 _sh(sh),
946 _cs(cs),
947 _concurrent(concurrent)
948 {}
949
950 void work(uint worker_id) {
951 if (_concurrent) {
952 ShenandoahConcurrentWorkerSession worker_session(worker_id);
953 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
954 ShenandoahEvacOOMScope oom_evac_scope;
955 do_work();
956 } else {
957 ShenandoahParallelWorkerSession worker_session(worker_id);
958 ShenandoahEvacOOMScope oom_evac_scope;
959 do_work();
960 }
961 }
962
963 private:
964 void do_work() {
965 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
966 ShenandoahHeapRegion* r;
967 while ((r =_cs->claim_next()) != NULL) {
968 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->index());
969 _sh->marked_object_iterate(r, &cl);
970
971 if (ShenandoahPacing) {
972 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
973 }
974
975 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
976 break;
977 }
978 }
979 }
980 };
981
982 void ShenandoahHeap::trash_cset_regions() {
983 ShenandoahHeapLocker locker(lock());
984
985 ShenandoahCollectionSet* set = collection_set();
986 ShenandoahHeapRegion* r;
987 set->clear_current_index();
988 while ((r = set->next()) != NULL) {
989 r->make_trash();
990 }
991 collection_set()->clear();
992 }
993
994 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
995 st->print_cr("Heap Regions:");
996 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
997 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
998 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start, UWM=update watermark");
999 st->print_cr("SN=alloc sequence number");
1000
1001 for (size_t i = 0; i < num_regions(); i++) {
1002 get_region(i)->print_on(st);
1003 }
1004 }
1005
1006 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1007 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1008
1009 oop humongous_obj = oop(start->bottom());
1010 size_t size = humongous_obj->size();
1011 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1012 size_t index = start->index() + required_regions - 1;
1013
1014 assert(!start->has_live(), "liveness must be zero");
1015
1016 for(size_t i = 0; i < required_regions; i++) {
1017 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1018 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1019 ShenandoahHeapRegion* region = get_region(index --);
1020
1021 assert(region->is_humongous(), "expect correct humongous start or continuation");
1022 assert(!region->is_cset(), "Humongous region should not be in collection set");
1023
1024 region->make_trash_immediate();
1025 }
1026 }
1027
1028 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1029 public:
1030 void do_thread(Thread* thread) {
1031 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1032 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1033 gclab->retire();
1034 }
1035 };
1036
1037 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1038 if (UseTLAB) {
1039 CollectedHeap::ensure_parsability(retire_tlabs);
1040 }
1041 ShenandoahRetireGCLABClosure cl;
1042 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1043 cl.do_thread(t);
1044 }
1045 workers()->threads_do(&cl);
1046 }
1047
1048 void ShenandoahHeap::resize_tlabs() {
1049 CollectedHeap::resize_all_tlabs();
1050 }
1051
1052 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1053 private:
1054 ShenandoahRootEvacuator* _rp;
1055
1056 public:
1057 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1058 AbstractGangTask("Shenandoah evacuate and update roots"),
1059 _rp(rp) {}
1060
1061 void work(uint worker_id) {
1062 ShenandoahParallelWorkerSession worker_session(worker_id);
1063 ShenandoahEvacOOMScope oom_evac_scope;
1064 ShenandoahEvacuateUpdateRootsClosure<> cl;
1065 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1066 _rp->roots_do(worker_id, &cl);
1067 }
1068 };
1069
1070 void ShenandoahHeap::evacuate_and_update_roots() {
1071 #if COMPILER2_OR_JVMCI
1072 DerivedPointerTable::clear();
1073 #endif
1074 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1075 {
1076 // Include concurrent roots if current cycle can not process those roots concurrently
1077 ShenandoahRootEvacuator rp(workers()->active_workers(),
1078 ShenandoahPhaseTimings::init_evac,
1079 !ShenandoahConcurrentRoots::should_do_concurrent_roots(),
1080 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1081 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1082 workers()->run_task(&roots_task);
1083 }
1084
1085 #if COMPILER2_OR_JVMCI
1086 DerivedPointerTable::update_pointers();
1087 #endif
1088 }
1089
1090 // Returns size in bytes
1091 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1092 if (ShenandoahElasticTLAB) {
1093 // With Elastic TLABs, return the max allowed size, and let the allocation path
1094 // figure out the safe size for current allocation.
1095 return ShenandoahHeapRegion::max_tlab_size_bytes();
1096 } else {
1097 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1098 }
1099 }
1100
1101 size_t ShenandoahHeap::max_tlab_size() const {
1102 // Returns size in words
1103 return ShenandoahHeapRegion::max_tlab_size_words();
1104 }
1105
1106 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1107 public:
1108 void do_thread(Thread* thread) {
1109 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1110 gclab->retire();
1111 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1112 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1113 }
1114 }
1115 };
1116
1117 void ShenandoahHeap::retire_and_reset_gclabs() {
1118 ShenandoahRetireAndResetGCLABClosure cl;
1119 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1120 cl.do_thread(t);
1121 }
1122 workers()->threads_do(&cl);
1123 }
1124
1125 void ShenandoahHeap::collect(GCCause::Cause cause) {
1126 control_thread()->request_gc(cause);
1127 }
1128
1129 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1130 //assert(false, "Shouldn't need to do full collections");
1131 }
1132
1133 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1134 ShenandoahHeapRegion* r = heap_region_containing(addr);
1135 if (r != NULL) {
1136 return r->block_start(addr);
1137 }
1138 return NULL;
1139 }
1140
1141 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1142 ShenandoahHeapRegion* r = heap_region_containing(addr);
1143 return r->block_is_obj(addr);
1144 }
1145
1146 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const {
1147 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr);
1148 }
1149
1150 jlong ShenandoahHeap::millis_since_last_gc() {
1151 double v = heuristics()->time_since_last_gc() * 1000;
1152 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1153 return (jlong)v;
1154 }
1155
1156 void ShenandoahHeap::prepare_for_verify() {
1157 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1158 make_parsable(false);
1159 }
1160 }
1161
1162 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1163 workers()->print_worker_threads_on(st);
1164 if (ShenandoahStringDedup::is_enabled()) {
1165 ShenandoahStringDedup::print_worker_threads_on(st);
1166 }
1167 }
1168
1169 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1170 workers()->threads_do(tcl);
1171 if (_safepoint_workers != NULL) {
1172 _safepoint_workers->threads_do(tcl);
1173 }
1174 if (ShenandoahStringDedup::is_enabled()) {
1175 ShenandoahStringDedup::threads_do(tcl);
1176 }
1177 }
1178
1179 void ShenandoahHeap::print_tracing_info() const {
1180 LogTarget(Info, gc, stats) lt;
1181 if (lt.is_enabled()) {
1182 ResourceMark rm;
1183 LogStream ls(lt);
1184
1185 phase_timings()->print_on(&ls);
1186
1187 ls.cr();
1188 ls.cr();
1189
1190 shenandoah_policy()->print_gc_stats(&ls);
1191
1192 ls.cr();
1193 ls.cr();
1194
1195 if (ShenandoahPacing) {
1196 pacer()->print_on(&ls);
1197 }
1198
1199 ls.cr();
1200 ls.cr();
1201 }
1202 }
1203
1204 void ShenandoahHeap::verify(VerifyOption vo) {
1205 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1206 if (ShenandoahVerify) {
1207 verifier()->verify_generic(vo);
1208 } else {
1209 // TODO: Consider allocating verification bitmaps on demand,
1210 // and turn this on unconditionally.
1211 }
1212 }
1213 }
1214 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1215 return _free_set->capacity();
1216 }
1217
1218 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1219 private:
1220 MarkBitMap* _bitmap;
1221 Stack<oop,mtGC>* _oop_stack;
1222 ShenandoahHeap* const _heap;
1223 ShenandoahMarkingContext* const _marking_context;
1224
1225 template <class T>
1226 void do_oop_work(T* p) {
1227 T o = RawAccess<>::oop_load(p);
1228 if (!CompressedOops::is_null(o)) {
1229 oop obj = CompressedOops::decode_not_null(o);
1230 if (_heap->is_concurrent_root_in_progress() && !_marking_context->is_marked(obj)) {
1231 // There may be dead oops in weak roots in concurrent root phase, do not touch them.
1232 return;
1233 }
1234 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1235
1236 assert(oopDesc::is_oop(obj), "must be a valid oop");
1237 if (!_bitmap->is_marked(obj)) {
1238 _bitmap->mark(obj);
1239 _oop_stack->push(obj);
1240 }
1241 }
1242 }
1243 public:
1244 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1245 _bitmap(bitmap), _oop_stack(oop_stack), _heap(ShenandoahHeap::heap()),
1246 _marking_context(_heap->marking_context()) {}
1247 void do_oop(oop* p) { do_oop_work(p); }
1248 void do_oop(narrowOop* p) { do_oop_work(p); }
1249 };
1250
1251 /*
1252 * This is public API, used in preparation of object_iterate().
1253 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1254 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1255 * control, we call SH::make_tlabs_parsable().
1256 */
1257 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1258 // No-op.
1259 }
1260
1261 /*
1262 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1263 *
1264 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1265 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1266 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1267 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1268 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1269 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1270 * wiped the bitmap in preparation for next marking).
1271 *
1272 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1273 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1274 * is allowed to report dead objects, but is not required to do so.
1275 */
1276 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1277 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1278 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1279 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1280 return;
1281 }
1282
1283 // Reset bitmap
1284 _aux_bit_map.clear();
1285
1286 Stack<oop,mtGC> oop_stack;
1287
1288 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects.
1289 ShenandoahHeapIterationRootScanner rp;
1290 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1291
1292 rp.roots_do(&oops);
1293
1294 // Work through the oop stack to traverse heap.
1295 while (! oop_stack.is_empty()) {
1296 oop obj = oop_stack.pop();
1297 assert(oopDesc::is_oop(obj), "must be a valid oop");
1298 cl->do_object(obj);
1299 obj->oop_iterate(&oops);
1300 }
1301
1302 assert(oop_stack.is_empty(), "should be empty");
1303
1304 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1305 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1306 }
1307 }
1308
1309 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1310 void ShenandoahHeap::keep_alive(oop obj) {
1311 if (is_concurrent_mark_in_progress()) {
1312 ShenandoahBarrierSet::barrier_set()->enqueue(obj);
1313 }
1314 }
1315
1316 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1317 for (size_t i = 0; i < num_regions(); i++) {
1318 ShenandoahHeapRegion* current = get_region(i);
1319 blk->heap_region_do(current);
1320 }
1321 }
1322
1323 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1324 private:
1325 ShenandoahHeap* const _heap;
1326 ShenandoahHeapRegionClosure* const _blk;
1327
1328 shenandoah_padding(0);
1329 volatile size_t _index;
1330 shenandoah_padding(1);
1331
1332 public:
1333 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1334 AbstractGangTask("Parallel Region Task"),
1335 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1336
1337 void work(uint worker_id) {
1338 size_t stride = ShenandoahParallelRegionStride;
1339
1340 size_t max = _heap->num_regions();
1341 while (_index < max) {
1342 size_t cur = Atomic::fetch_and_add(&_index, stride);
1343 size_t start = cur;
1344 size_t end = MIN2(cur + stride, max);
1345 if (start >= max) break;
1346
1347 for (size_t i = cur; i < end; i++) {
1348 ShenandoahHeapRegion* current = _heap->get_region(i);
1349 _blk->heap_region_do(current);
1350 }
1351 }
1352 }
1353 };
1354
1355 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1356 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1357 if (num_regions() > ShenandoahParallelRegionStride) {
1358 ShenandoahParallelHeapRegionTask task(blk);
1359 workers()->run_task(&task);
1360 } else {
1361 heap_region_iterate(blk);
1362 }
1363 }
1364
1365 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1366 private:
1367 ShenandoahMarkingContext* const _ctx;
1368 public:
1369 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1370
1371 void heap_region_do(ShenandoahHeapRegion* r) {
1372 if (r->is_active()) {
1373 r->clear_live_data();
1374 _ctx->capture_top_at_mark_start(r);
1375 } else {
1376 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
1377 assert(_ctx->top_at_mark_start(r) == r->top(),
1378 "Region " SIZE_FORMAT " should already have correct TAMS", r->index());
1379 }
1380 }
1381
1382 bool is_thread_safe() { return true; }
1383 };
1384
1385 void ShenandoahHeap::op_init_mark() {
1386 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1387 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1388
1389 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1390 assert(!marking_context()->is_complete(), "should not be complete");
1391 assert(!has_forwarded_objects(), "No forwarded objects on this path");
1392
1393 if (ShenandoahVerify) {
1394 verifier()->verify_before_concmark();
1395 }
1396
1397 if (VerifyBeforeGC) {
1398 Universe::verify();
1399 }
1400
1401 set_concurrent_mark_in_progress(true);
1402 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1403 {
1404 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1405 make_parsable(true);
1406 }
1407
1408 {
1409 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1410 ShenandoahClearLivenessClosure clc;
1411 parallel_heap_region_iterate(&clc);
1412 }
1413
1414 // Make above changes visible to worker threads
1415 OrderAccess::fence();
1416
1417 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1418
1419 if (UseTLAB) {
1420 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1421 resize_tlabs();
1422 }
1423
1424 if (ShenandoahPacing) {
1425 pacer()->setup_for_mark();
1426 }
1427
1428 // Arm nmethods for concurrent marking. When a nmethod is about to be executed,
1429 // we need to make sure that all its metadata are marked. alternative is to remark
1430 // thread roots at final mark pause, but it can be potential latency killer.
1431 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1432 ShenandoahCodeRoots::arm_nmethods();
1433 }
1434 }
1435
1436 void ShenandoahHeap::op_mark() {
1437 concurrent_mark()->mark_from_roots();
1438 }
1439
1440 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1441 private:
1442 ShenandoahMarkingContext* const _ctx;
1443 public:
1444 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1445
1446 void heap_region_do(ShenandoahHeapRegion* r) {
1447 if (r->is_active()) {
1448 HeapWord *tams = _ctx->top_at_mark_start(r);
1449 HeapWord *top = r->top();
1450 if (top > tams) {
1451 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1452 }
1453 } else {
1454 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
1455 assert(_ctx->top_at_mark_start(r) == r->top(),
1456 "Region " SIZE_FORMAT " should have correct TAMS", r->index());
1457 }
1458 }
1459
1460 bool is_thread_safe() { return true; }
1461 };
1462
1463 void ShenandoahHeap::op_final_mark() {
1464 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1465 assert(!has_forwarded_objects(), "No forwarded objects on this path");
1466
1467 // It is critical that we
1468 // evacuate roots right after finishing marking, so that we don't
1469 // get unmarked objects in the roots.
1470
1471 if (!cancelled_gc()) {
1472 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1473
1474 // Marking is completed, deactivate SATB barrier
1475 set_concurrent_mark_in_progress(false);
1476 mark_complete_marking_context();
1477
1478 parallel_cleaning(false /* full gc*/);
1479
1480 if (ShenandoahVerify) {
1481 verifier()->verify_roots_no_forwarded();
1482 }
1483 // All allocations past TAMS are implicitly live, adjust the region data.
1484 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1485 {
1486 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1487 ShenandoahCompleteLivenessClosure cl;
1488 parallel_heap_region_iterate(&cl);
1489 }
1490
1491 // Force the threads to reacquire their TLABs outside the collection set.
1492 {
1493 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs);
1494 make_parsable(true);
1495 }
1496
1497 // We are about to select the collection set, make sure it knows about
1498 // current pinning status. Also, this allows trashing more regions that
1499 // now have their pinning status dropped.
1500 {
1501 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned);
1502 sync_pinned_region_status();
1503 }
1504
1505 {
1506 ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac);
1507
1508 ShenandoahHeapLocker locker(lock());
1509 _collection_set->clear();
1510 _free_set->clear();
1511
1512 heuristics()->choose_collection_set(_collection_set);
1513
1514 _free_set->rebuild();
1515 }
1516
1517 if (!is_degenerated_gc_in_progress()) {
1518 prepare_concurrent_roots();
1519 prepare_concurrent_unloading();
1520 }
1521
1522 // If collection set has candidates, start evacuation.
1523 // Otherwise, bypass the rest of the cycle.
1524 if (!collection_set()->is_empty()) {
1525 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1526
1527 if (ShenandoahVerify) {
1528 verifier()->verify_before_evacuation();
1529 }
1530
1531 // Remember limit for updating refs. It's guaranteed that we get no from-space-refs written
1532 // from here on.
1533 for (uint i = 0; i < num_regions(); i++) {
1534 ShenandoahHeapRegion* r = get_region(i);
1535 r->set_update_watermark(r->top());
1536 }
1537
1538 set_evacuation_in_progress(true);
1539 // From here on, we need to update references.
1540 set_has_forwarded_objects(true);
1541
1542 if (!is_degenerated_gc_in_progress()) {
1543 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1544 ShenandoahCodeRoots::arm_nmethods();
1545 }
1546 evacuate_and_update_roots();
1547 }
1548
1549 if (ShenandoahPacing) {
1550 pacer()->setup_for_evac();
1551 }
1552
1553 if (ShenandoahVerify) {
1554 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None;
1555 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1556 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots);
1557 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots);
1558 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::StringDedupRoots);
1559 }
1560
1561 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1562 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CodeRoots);
1563 }
1564 verifier()->verify_roots_no_forwarded_except(types);
1565 verifier()->verify_during_evacuation();
1566 }
1567 } else {
1568 if (ShenandoahVerify) {
1569 verifier()->verify_after_concmark();
1570 }
1571
1572 if (VerifyAfterGC) {
1573 Universe::verify();
1574 }
1575 }
1576
1577 } else {
1578 // If this cycle was updating references, we need to keep the has_forwarded_objects
1579 // flag on, for subsequent phases to deal with it.
1580 concurrent_mark()->cancel();
1581 set_concurrent_mark_in_progress(false);
1582
1583 if (process_references()) {
1584 // Abandon reference processing right away: pre-cleaning must have failed.
1585 ReferenceProcessor *rp = ref_processor();
1586 rp->disable_discovery();
1587 rp->abandon_partial_discovery();
1588 rp->verify_no_references_recorded();
1589 }
1590 }
1591 }
1592
1593 void ShenandoahHeap::op_conc_evac() {
1594 ShenandoahEvacuationTask task(this, _collection_set, true);
1595 workers()->run_task(&task);
1596 }
1597
1598 void ShenandoahHeap::op_stw_evac() {
1599 ShenandoahEvacuationTask task(this, _collection_set, false);
1600 workers()->run_task(&task);
1601 }
1602
1603 void ShenandoahHeap::op_updaterefs() {
1604 update_heap_references(true);
1605 }
1606
1607 void ShenandoahHeap::op_cleanup() {
1608 free_set()->recycle_trash();
1609 }
1610
1611 class ShenandoahConcurrentRootsEvacUpdateTask : public AbstractGangTask {
1612 private:
1613 ShenandoahVMRoots<true /*concurrent*/> _vm_roots;
1614 ShenandoahWeakRoots<true /*concurrent*/> _weak_roots;
1615 ShenandoahClassLoaderDataRoots<true /*concurrent*/, false /*single threaded*/> _cld_roots;
1616 ShenandoahConcurrentStringDedupRoots _dedup_roots;
1617 bool _include_weak_roots;
1618
1619 public:
1620 ShenandoahConcurrentRootsEvacUpdateTask(bool include_weak_roots) :
1621 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task"),
1622 _include_weak_roots(include_weak_roots) {
1623 }
1624
1625 void work(uint worker_id) {
1626 ShenandoahEvacOOMScope oom;
1627 {
1628 // vm_roots and weak_roots are OopStorage backed roots, concurrent iteration
1629 // may race against OopStorage::release() calls.
1630 ShenandoahEvacUpdateOopStorageRootsClosure cl;
1631 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1632
1633 if (_include_weak_roots) {
1634 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1635 }
1636 }
1637
1638 {
1639 ShenandoahEvacuateUpdateRootsClosure<> cl;
1640 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong);
1641 _cld_roots.cld_do(&clds);
1642 }
1643
1644 {
1645 ShenandoahForwardedIsAliveClosure is_alive;
1646 ShenandoahEvacuateUpdateRootsClosure<MO_RELEASE> keep_alive;
1647 _dedup_roots.oops_do(&is_alive, &keep_alive, worker_id);
1648 }
1649 }
1650 };
1651
1652 class ShenandoahEvacUpdateCleanupOopStorageRootsClosure : public BasicOopIterateClosure {
1653 private:
1654 ShenandoahHeap* const _heap;
1655 ShenandoahMarkingContext* const _mark_context;
1656 bool _evac_in_progress;
1657 Thread* const _thread;
1658 size_t _dead_counter;
1659
1660 public:
1661 ShenandoahEvacUpdateCleanupOopStorageRootsClosure();
1662 void do_oop(oop* p);
1663 void do_oop(narrowOop* p);
1664
1665 size_t dead_counter() const;
1666 void reset_dead_counter();
1667 };
1668
1669 ShenandoahEvacUpdateCleanupOopStorageRootsClosure::ShenandoahEvacUpdateCleanupOopStorageRootsClosure() :
1670 _heap(ShenandoahHeap::heap()),
1671 _mark_context(ShenandoahHeap::heap()->marking_context()),
1672 _evac_in_progress(ShenandoahHeap::heap()->is_evacuation_in_progress()),
1673 _thread(Thread::current()),
1674 _dead_counter(0) {
1675 }
1676
1677 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(oop* p) {
1678 const oop obj = RawAccess<>::oop_load(p);
1679 if (!CompressedOops::is_null(obj)) {
1680 if (!_mark_context->is_marked(obj)) {
1681 shenandoah_assert_correct(p, obj);
1682 oop old = Atomic::cmpxchg(p, obj, oop(NULL));
1683 if (obj == old) {
1684 _dead_counter ++;
1685 }
1686 } else if (_evac_in_progress && _heap->in_collection_set(obj)) {
1687 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1688 if (resolved == obj) {
1689 resolved = _heap->evacuate_object(obj, _thread);
1690 }
1691 Atomic::cmpxchg(p, obj, resolved);
1692 assert(_heap->cancelled_gc() ||
1693 _mark_context->is_marked(resolved) && !_heap->in_collection_set(resolved),
1694 "Sanity");
1695 }
1696 }
1697 }
1698
1699 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(narrowOop* p) {
1700 ShouldNotReachHere();
1701 }
1702
1703 size_t ShenandoahEvacUpdateCleanupOopStorageRootsClosure::dead_counter() const {
1704 return _dead_counter;
1705 }
1706
1707 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::reset_dead_counter() {
1708 _dead_counter = 0;
1709 }
1710
1711 // This task not only evacuates/updates marked weak roots, but also "NULL"
1712 // dead weak roots.
1713 class ShenandoahConcurrentWeakRootsEvacUpdateTask : public AbstractGangTask {
1714 private:
1715 ShenandoahWeakRoot<true /*concurrent*/> _jni_roots;
1716 ShenandoahWeakRoot<true /*concurrent*/> _string_table_roots;
1717 ShenandoahWeakRoot<true /*concurrent*/> _resolved_method_table_roots;
1718 ShenandoahWeakRoot<true /*concurrent*/> _vm_roots;
1719
1720 public:
1721 ShenandoahConcurrentWeakRootsEvacUpdateTask() :
1722 AbstractGangTask("Shenandoah Concurrent Weak Root Task"),
1723 _jni_roots(OopStorageSet::jni_weak(), ShenandoahPhaseTimings::JNIWeakRoots),
1724 _string_table_roots(OopStorageSet::string_table_weak(), ShenandoahPhaseTimings::StringTableRoots),
1725 _resolved_method_table_roots(OopStorageSet::resolved_method_table_weak(), ShenandoahPhaseTimings::ResolvedMethodTableRoots),
1726 _vm_roots(OopStorageSet::vm_weak(), ShenandoahPhaseTimings::VMWeakRoots) {
1727 StringTable::reset_dead_counter();
1728 ResolvedMethodTable::reset_dead_counter();
1729 }
1730
1731 ~ShenandoahConcurrentWeakRootsEvacUpdateTask() {
1732 StringTable::finish_dead_counter();
1733 ResolvedMethodTable::finish_dead_counter();
1734 }
1735
1736 void work(uint worker_id) {
1737 ShenandoahEvacOOMScope oom;
1738 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration
1739 // may race against OopStorage::release() calls.
1740 ShenandoahEvacUpdateCleanupOopStorageRootsClosure cl;
1741 _jni_roots.oops_do(&cl, worker_id);
1742 _vm_roots.oops_do(&cl, worker_id);
1743
1744 cl.reset_dead_counter();
1745 _string_table_roots.oops_do(&cl, worker_id);
1746 StringTable::inc_dead_counter(cl.dead_counter());
1747
1748 cl.reset_dead_counter();
1749 _resolved_method_table_roots.oops_do(&cl, worker_id);
1750 ResolvedMethodTable::inc_dead_counter(cl.dead_counter());
1751 }
1752 };
1753
1754 void ShenandoahHeap::op_roots() {
1755 if (is_concurrent_root_in_progress()) {
1756 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1757 // Concurrent weak root processing
1758 ShenandoahConcurrentWeakRootsEvacUpdateTask task;
1759 workers()->run_task(&task);
1760
1761 _unloader.unload();
1762 }
1763
1764 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1765 ShenandoahConcurrentRootsEvacUpdateTask task(!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1766 workers()->run_task(&task);
1767 }
1768 }
1769
1770 set_concurrent_root_in_progress(false);
1771 }
1772
1773 void ShenandoahHeap::op_reset() {
1774 if (ShenandoahPacing) {
1775 pacer()->setup_for_reset();
1776 }
1777 reset_mark_bitmap();
1778 }
1779
1780 void ShenandoahHeap::op_preclean() {
1781 if (ShenandoahPacing) {
1782 pacer()->setup_for_preclean();
1783 }
1784 concurrent_mark()->preclean_weak_refs();
1785 }
1786
1787 void ShenandoahHeap::op_init_traversal() {
1788 traversal_gc()->init_traversal_collection();
1789 }
1790
1791 void ShenandoahHeap::op_traversal() {
1792 traversal_gc()->concurrent_traversal_collection();
1793 }
1794
1795 void ShenandoahHeap::op_final_traversal() {
1796 traversal_gc()->final_traversal_collection();
1797 }
1798
1799 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1800 ShenandoahMetricsSnapshot metrics;
1801 metrics.snap_before();
1802
1803 full_gc()->do_it(cause);
1804 if (UseTLAB) {
1805 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1806 resize_all_tlabs();
1807 }
1808
1809 metrics.snap_after();
1810
1811 if (metrics.is_good_progress()) {
1812 _progress_last_gc.set();
1813 } else {
1814 // Nothing to do. Tell the allocation path that we have failed to make
1815 // progress, and it can finally fail.
1816 _progress_last_gc.unset();
1817 }
1818 }
1819
1820 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1821 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1822 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1823 // some phase, we have to upgrade the Degenerate GC to Full GC.
1824
1825 clear_cancelled_gc();
1826
1827 ShenandoahMetricsSnapshot metrics;
1828 metrics.snap_before();
1829
1830 switch (point) {
1831 case _degenerated_traversal:
1832 {
1833 // Drop the collection set. Note: this leaves some already forwarded objects
1834 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1835 // workarounds in ShenandoahTraversalHeuristics.
1836
1837 ShenandoahHeapLocker locker(lock());
1838 collection_set()->clear_current_index();
1839 for (size_t i = 0; i < collection_set()->count(); i++) {
1840 ShenandoahHeapRegion* r = collection_set()->next();
1841 r->make_regular_bypass();
1842 }
1843 collection_set()->clear();
1844 }
1845 op_final_traversal();
1846 op_cleanup();
1847 return;
1848
1849 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1850 // but enters it at different points, depending on which concurrent phase had
1851 // degenerated.
1852
1853 case _degenerated_outside_cycle:
1854 // We have degenerated from outside the cycle, which means something is bad with
1855 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1856 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1857 // we can do the most aggressive degen cycle, which includes processing references and
1858 // class unloading, unless those features are explicitly disabled.
1859 //
1860 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1861 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1862 set_process_references(heuristics()->can_process_references());
1863 set_unload_classes(heuristics()->can_unload_classes());
1864
1865 if (is_traversal_mode()) {
1866 // Not possible to degenerate from here, upgrade to Full GC right away.
1867 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1868 op_degenerated_fail();
1869 return;
1870 }
1871
1872 op_reset();
1873
1874 op_init_mark();
1875 if (cancelled_gc()) {
1876 op_degenerated_fail();
1877 return;
1878 }
1879
1880 case _degenerated_mark:
1881 op_final_mark();
1882 if (cancelled_gc()) {
1883 op_degenerated_fail();
1884 return;
1885 }
1886
1887 if (!has_forwarded_objects() && ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) {
1888 // Disarm nmethods that armed for concurrent mark. On normal cycle, it would
1889 // be disarmed while conc-roots phase is running.
1890 // TODO: Call op_conc_roots() here instead
1891 ShenandoahCodeRoots::disarm_nmethods();
1892 }
1893
1894 op_cleanup();
1895
1896 case _degenerated_evac:
1897 // If heuristics thinks we should do the cycle, this flag would be set,
1898 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1899 if (is_evacuation_in_progress()) {
1900
1901 // Degeneration under oom-evac protocol might have left some objects in
1902 // collection set un-evacuated. Restart evacuation from the beginning to
1903 // capture all objects. For all the objects that are already evacuated,
1904 // it would be a simple check, which is supposed to be fast. This is also
1905 // safe to do even without degeneration, as CSet iterator is at beginning
1906 // in preparation for evacuation anyway.
1907 //
1908 // Before doing that, we need to make sure we never had any cset-pinned
1909 // regions. This may happen if allocation failure happened when evacuating
1910 // the about-to-be-pinned object, oom-evac protocol left the object in
1911 // the collection set, and then the pin reached the cset region. If we continue
1912 // the cycle here, we would trash the cset and alive objects in it. To avoid
1913 // it, we fail degeneration right away and slide into Full GC to recover.
1914
1915 {
1916 sync_pinned_region_status();
1917 collection_set()->clear_current_index();
1918
1919 ShenandoahHeapRegion* r;
1920 while ((r = collection_set()->next()) != NULL) {
1921 if (r->is_pinned()) {
1922 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1923 op_degenerated_fail();
1924 return;
1925 }
1926 }
1927
1928 collection_set()->clear_current_index();
1929 }
1930
1931 op_stw_evac();
1932 if (cancelled_gc()) {
1933 op_degenerated_fail();
1934 return;
1935 }
1936 }
1937
1938 // If heuristics thinks we should do the cycle, this flag would be set,
1939 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1940 if (has_forwarded_objects()) {
1941 op_init_updaterefs();
1942 if (cancelled_gc()) {
1943 op_degenerated_fail();
1944 return;
1945 }
1946 }
1947
1948 case _degenerated_updaterefs:
1949 if (has_forwarded_objects()) {
1950 op_final_updaterefs();
1951 if (cancelled_gc()) {
1952 op_degenerated_fail();
1953 return;
1954 }
1955 }
1956
1957 op_cleanup();
1958 break;
1959
1960 default:
1961 ShouldNotReachHere();
1962 }
1963
1964 if (ShenandoahVerify) {
1965 verifier()->verify_after_degenerated();
1966 }
1967
1968 if (VerifyAfterGC) {
1969 Universe::verify();
1970 }
1971
1972 metrics.snap_after();
1973
1974 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1975 // because that probably means the heap is overloaded and/or fragmented.
1976 if (!metrics.is_good_progress()) {
1977 _progress_last_gc.unset();
1978 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1979 op_degenerated_futile();
1980 } else {
1981 _progress_last_gc.set();
1982 }
1983 }
1984
1985 void ShenandoahHeap::op_degenerated_fail() {
1986 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1987 shenandoah_policy()->record_degenerated_upgrade_to_full();
1988 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1989 }
1990
1991 void ShenandoahHeap::op_degenerated_futile() {
1992 shenandoah_policy()->record_degenerated_upgrade_to_full();
1993 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1994 }
1995
1996 void ShenandoahHeap::force_satb_flush_all_threads() {
1997 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1998 // No need to flush SATBs
1999 return;
2000 }
2001
2002 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2003 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
2004 }
2005 // The threads are not "acquiring" their thread-local data, but it does not
2006 // hurt to "release" the updates here anyway.
2007 OrderAccess::fence();
2008 }
2009
2010 void ShenandoahHeap::set_gc_state_all_threads(char state) {
2011 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2012 ShenandoahThreadLocalData::set_gc_state(t, state);
2013 }
2014 }
2015
2016 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
2017 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
2018 _gc_state.set_cond(mask, value);
2019 set_gc_state_all_threads(_gc_state.raw_value());
2020 }
2021
2022 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
2023 if (has_forwarded_objects()) {
2024 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
2025 } else {
2026 set_gc_state_mask(MARKING, in_progress);
2027 }
2028 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2029 }
2030
2031 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
2032 set_gc_state_mask(TRAVERSAL, in_progress);
2033 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2034 }
2035
2036 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2037 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
2038 set_gc_state_mask(EVACUATION, in_progress);
2039 }
2040
2041 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) {
2042 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?");
2043 if (in_progress) {
2044 _concurrent_root_in_progress.set();
2045 } else {
2046 _concurrent_root_in_progress.unset();
2047 }
2048 }
2049
2050 void ShenandoahHeap::ref_processing_init() {
2051 assert(_max_workers > 0, "Sanity");
2052
2053 _ref_processor =
2054 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
2055 ParallelRefProcEnabled, // MT processing
2056 _max_workers, // Degree of MT processing
2057 true, // MT discovery
2058 _max_workers, // Degree of MT discovery
2059 false, // Reference discovery is not atomic
2060 NULL, // No closure, should be installed before use
2061 true); // Scale worker threads
2062
2063 shenandoah_assert_rp_isalive_not_installed();
2064 }
2065
2066 GCTracer* ShenandoahHeap::tracer() {
2067 return shenandoah_policy()->tracer();
2068 }
2069
2070 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2071 return _free_set->used();
2072 }
2073
2074 bool ShenandoahHeap::try_cancel_gc() {
2075 while (true) {
2076 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
2077 if (prev == CANCELLABLE) return true;
2078 else if (prev == CANCELLED) return false;
2079 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
2080 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
2081 if (Thread::current()->is_Java_thread()) {
2082 // We need to provide a safepoint here, otherwise we might
2083 // spin forever if a SP is pending.
2084 ThreadBlockInVM sp(JavaThread::current());
2085 SpinPause();
2086 }
2087 }
2088 }
2089
2090 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
2091 if (try_cancel_gc()) {
2092 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
2093 log_info(gc)("%s", msg.buffer());
2094 Events::log(Thread::current(), "%s", msg.buffer());
2095 }
2096 }
2097
2098 uint ShenandoahHeap::max_workers() {
2099 return _max_workers;
2100 }
2101
2102 void ShenandoahHeap::stop() {
2103 // The shutdown sequence should be able to terminate when GC is running.
2104
2105 // Step 0. Notify policy to disable event recording.
2106 _shenandoah_policy->record_shutdown();
2107
2108 // Step 1. Notify control thread that we are in shutdown.
2109 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2110 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2111 control_thread()->prepare_for_graceful_shutdown();
2112
2113 // Step 2. Notify GC workers that we are cancelling GC.
2114 cancel_gc(GCCause::_shenandoah_stop_vm);
2115
2116 // Step 3. Wait until GC worker exits normally.
2117 control_thread()->stop();
2118
2119 // Step 4. Stop String Dedup thread if it is active
2120 if (ShenandoahStringDedup::is_enabled()) {
2121 ShenandoahStringDedup::stop();
2122 }
2123 }
2124
2125 void ShenandoahHeap::stw_unload_classes(bool full_gc) {
2126 if (!unload_classes()) return;
2127 bool purged_class;
2128
2129 // Unload classes and purge SystemDictionary.
2130 {
2131 ShenandoahGCPhase phase(full_gc ?
2132 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2133 ShenandoahPhaseTimings::purge_class_unload);
2134 purged_class = SystemDictionary::do_unloading(gc_timer());
2135 }
2136
2137 {
2138 ShenandoahGCPhase phase(full_gc ?
2139 ShenandoahPhaseTimings::full_gc_purge_par :
2140 ShenandoahPhaseTimings::purge_par);
2141 ShenandoahIsAliveSelector is_alive;
2142 uint num_workers = _workers->active_workers();
2143 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class);
2144 _workers->run_task(&unlink_task);
2145 }
2146
2147 {
2148 ShenandoahGCPhase phase(full_gc ?
2149 ShenandoahPhaseTimings::full_gc_purge_cldg :
2150 ShenandoahPhaseTimings::purge_cldg);
2151 ClassLoaderDataGraph::purge();
2152 }
2153 // Resize and verify metaspace
2154 MetaspaceGC::compute_new_size();
2155 MetaspaceUtils::verify_metrics();
2156 }
2157
2158 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs),
2159 // so they should not have forwarded oops.
2160 // However, we do need to "null" dead oops in the roots, if can not be done
2161 // in concurrent cycles.
2162 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) {
2163 ShenandoahGCPhase root_phase(full_gc ?
2164 ShenandoahPhaseTimings::full_gc_purge :
2165 ShenandoahPhaseTimings::purge);
2166 uint num_workers = _workers->active_workers();
2167 ShenandoahPhaseTimings::Phase timing_phase = full_gc ?
2168 ShenandoahPhaseTimings::full_gc_purge_par :
2169 ShenandoahPhaseTimings::purge_par;
2170 ShenandoahGCPhase phase(timing_phase);
2171 ShenandoahGCWorkerPhase worker_phase(timing_phase);
2172
2173 // Cleanup weak roots
2174 if (has_forwarded_objects()) {
2175 ShenandoahForwardedIsAliveClosure is_alive;
2176 ShenandoahUpdateRefsClosure keep_alive;
2177 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure>
2178 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2179 _workers->run_task(&cleaning_task);
2180 } else {
2181 ShenandoahIsAliveClosure is_alive;
2182 #ifdef ASSERT
2183 ShenandoahAssertNotForwardedClosure verify_cl;
2184 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure>
2185 cleaning_task(&is_alive, &verify_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2186 #else
2187 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure>
2188 cleaning_task(&is_alive, &do_nothing_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2189 #endif
2190 _workers->run_task(&cleaning_task);
2191 }
2192 }
2193
2194 void ShenandoahHeap::parallel_cleaning(bool full_gc) {
2195 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2196 stw_process_weak_roots(full_gc);
2197 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2198 stw_unload_classes(full_gc);
2199 }
2200 }
2201
2202 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2203 if (is_traversal_mode()) {
2204 set_gc_state_mask(HAS_FORWARDED | UPDATEREFS, cond);
2205 } else {
2206 set_gc_state_mask(HAS_FORWARDED, cond);
2207 }
2208
2209 }
2210
2211 void ShenandoahHeap::set_process_references(bool pr) {
2212 _process_references.set_cond(pr);
2213 }
2214
2215 void ShenandoahHeap::set_unload_classes(bool uc) {
2216 _unload_classes.set_cond(uc);
2217 }
2218
2219 bool ShenandoahHeap::process_references() const {
2220 return _process_references.is_set();
2221 }
2222
2223 bool ShenandoahHeap::unload_classes() const {
2224 return _unload_classes.is_set();
2225 }
2226
2227 address ShenandoahHeap::in_cset_fast_test_addr() {
2228 ShenandoahHeap* heap = ShenandoahHeap::heap();
2229 assert(heap->collection_set() != NULL, "Sanity");
2230 return (address) heap->collection_set()->biased_map_address();
2231 }
2232
2233 address ShenandoahHeap::cancelled_gc_addr() {
2234 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2235 }
2236
2237 address ShenandoahHeap::gc_state_addr() {
2238 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2239 }
2240
2241 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2242 return Atomic::load_acquire(&_bytes_allocated_since_gc_start);
2243 }
2244
2245 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2246 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2247 }
2248
2249 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2250 _degenerated_gc_in_progress.set_cond(in_progress);
2251 }
2252
2253 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2254 _full_gc_in_progress.set_cond(in_progress);
2255 }
2256
2257 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2258 assert (is_full_gc_in_progress(), "should be");
2259 _full_gc_move_in_progress.set_cond(in_progress);
2260 }
2261
2262 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2263 set_gc_state_mask(UPDATEREFS, in_progress);
2264 }
2265
2266 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2267 ShenandoahCodeRoots::register_nmethod(nm);
2268 }
2269
2270 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2271 ShenandoahCodeRoots::unregister_nmethod(nm);
2272 }
2273
2274 void ShenandoahHeap::flush_nmethod(nmethod* nm) {
2275 ShenandoahCodeRoots::flush_nmethod(nm);
2276 }
2277
2278 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2279 heap_region_containing(o)->record_pin();
2280 return o;
2281 }
2282
2283 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2284 heap_region_containing(o)->record_unpin();
2285 }
2286
2287 void ShenandoahHeap::sync_pinned_region_status() {
2288 ShenandoahHeapLocker locker(lock());
2289
2290 for (size_t i = 0; i < num_regions(); i++) {
2291 ShenandoahHeapRegion *r = get_region(i);
2292 if (r->is_active()) {
2293 if (r->is_pinned()) {
2294 if (r->pin_count() == 0) {
2295 r->make_unpinned();
2296 }
2297 } else {
2298 if (r->pin_count() > 0) {
2299 r->make_pinned();
2300 }
2301 }
2302 }
2303 }
2304
2305 assert_pinned_region_status();
2306 }
2307
2308 #ifdef ASSERT
2309 void ShenandoahHeap::assert_pinned_region_status() {
2310 for (size_t i = 0; i < num_regions(); i++) {
2311 ShenandoahHeapRegion* r = get_region(i);
2312 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0),
2313 "Region " SIZE_FORMAT " pinning status is inconsistent", i);
2314 }
2315 }
2316 #endif
2317
2318 GCTimer* ShenandoahHeap::gc_timer() const {
2319 return _gc_timer;
2320 }
2321
2322 void ShenandoahHeap::prepare_concurrent_roots() {
2323 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2324 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
2325 set_concurrent_root_in_progress(true);
2326 }
2327 }
2328
2329 void ShenandoahHeap::prepare_concurrent_unloading() {
2330 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2331 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2332 _unloader.prepare();
2333 }
2334 }
2335
2336 void ShenandoahHeap::finish_concurrent_unloading() {
2337 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2338 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2339 _unloader.finish();
2340 }
2341 }
2342
2343 #ifdef ASSERT
2344 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2345 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2346
2347 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2348 if (UseDynamicNumberOfGCThreads) {
2349 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2350 } else {
2351 // Use ParallelGCThreads inside safepoints
2352 assert(nworkers == ParallelGCThreads, "Use ParallelGCThreads within safepoints");
2353 }
2354 } else {
2355 if (UseDynamicNumberOfGCThreads) {
2356 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2357 } else {
2358 // Use ConcGCThreads outside safepoints
2359 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2360 }
2361 }
2362 }
2363 #endif
2364
2365 ShenandoahVerifier* ShenandoahHeap::verifier() {
2366 guarantee(ShenandoahVerify, "Should be enabled");
2367 assert (_verifier != NULL, "sanity");
2368 return _verifier;
2369 }
2370
2371 template<class T>
2372 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2373 private:
2374 T cl;
2375 ShenandoahHeap* _heap;
2376 ShenandoahRegionIterator* _regions;
2377 bool _concurrent;
2378 public:
2379 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2380 AbstractGangTask("Concurrent Update References Task"),
2381 cl(T()),
2382 _heap(ShenandoahHeap::heap()),
2383 _regions(regions),
2384 _concurrent(concurrent) {
2385 }
2386
2387 void work(uint worker_id) {
2388 if (_concurrent) {
2389 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2390 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2391 do_work();
2392 } else {
2393 ShenandoahParallelWorkerSession worker_session(worker_id);
2394 do_work();
2395 }
2396 }
2397
2398 private:
2399 void do_work() {
2400 ShenandoahHeapRegion* r = _regions->next();
2401 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2402 while (r != NULL) {
2403 HeapWord* update_watermark = r->get_update_watermark();
2404 assert (update_watermark >= r->bottom(), "sanity");
2405 if (r->is_active() && !r->is_cset()) {
2406 _heap->marked_object_oop_iterate(r, &cl, update_watermark);
2407 }
2408 if (ShenandoahPacing) {
2409 _heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom()));
2410 }
2411 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2412 return;
2413 }
2414 r = _regions->next();
2415 }
2416 }
2417 };
2418
2419 void ShenandoahHeap::update_heap_references(bool concurrent) {
2420 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2421 workers()->run_task(&task);
2422 }
2423
2424 void ShenandoahHeap::op_init_updaterefs() {
2425 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2426
2427 set_evacuation_in_progress(false);
2428
2429 {
2430 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs);
2431 retire_and_reset_gclabs();
2432 }
2433
2434 if (ShenandoahVerify) {
2435 if (!is_degenerated_gc_in_progress()) {
2436 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2437 }
2438 verifier()->verify_before_updaterefs();
2439 }
2440
2441 set_update_refs_in_progress(true);
2442
2443 {
2444 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare);
2445
2446 make_parsable(true);
2447
2448 // Reset iterator.
2449 _update_refs_iterator.reset();
2450 }
2451
2452 if (ShenandoahPacing) {
2453 pacer()->setup_for_updaterefs();
2454 }
2455 }
2456
2457 void ShenandoahHeap::op_final_updaterefs() {
2458 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2459
2460 finish_concurrent_unloading();
2461
2462 // Check if there is left-over work, and finish it
2463 if (_update_refs_iterator.has_next()) {
2464 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work);
2465
2466 // Finish updating references where we left off.
2467 clear_cancelled_gc();
2468 update_heap_references(false);
2469 }
2470
2471 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2472 // everything. On degenerated paths, cancelled gc would not be set anyway.
2473 if (cancelled_gc()) {
2474 clear_cancelled_gc();
2475 }
2476 assert(!cancelled_gc(), "Should have been done right before");
2477
2478 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) {
2479 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2480 }
2481
2482 if (is_degenerated_gc_in_progress()) {
2483 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
2484 } else {
2485 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2486 }
2487
2488 // Has to be done before cset is clear
2489 if (ShenandoahVerify) {
2490 verifier()->verify_roots_in_to_space();
2491 }
2492
2493 // Drop unnecessary "pinned" state from regions that does not have CP marks
2494 // anymore, as this would allow trashing them below.
2495 {
2496 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned);
2497 sync_pinned_region_status();
2498 }
2499
2500 {
2501 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset);
2502 trash_cset_regions();
2503 }
2504
2505 set_has_forwarded_objects(false);
2506 set_update_refs_in_progress(false);
2507
2508 if (ShenandoahVerify) {
2509 verifier()->verify_after_updaterefs();
2510 }
2511
2512 if (VerifyAfterGC) {
2513 Universe::verify();
2514 }
2515
2516 {
2517 ShenandoahHeapLocker locker(lock());
2518 _free_set->rebuild();
2519 }
2520 }
2521
2522 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2523 print_on(st);
2524 print_heap_regions_on(st);
2525 }
2526
2527 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2528 size_t slice = r->index() / _bitmap_regions_per_slice;
2529
2530 size_t regions_from = _bitmap_regions_per_slice * slice;
2531 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2532 for (size_t g = regions_from; g < regions_to; g++) {
2533 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2534 if (skip_self && g == r->index()) continue;
2535 if (get_region(g)->is_committed()) {
2536 return true;
2537 }
2538 }
2539 return false;
2540 }
2541
2542 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2543 shenandoah_assert_heaplocked();
2544
2545 // Bitmaps in special regions do not need commits
2546 if (_bitmap_region_special) {
2547 return true;
2548 }
2549
2550 if (is_bitmap_slice_committed(r, true)) {
2551 // Some other region from the group is already committed, meaning the bitmap
2552 // slice is already committed, we exit right away.
2553 return true;
2554 }
2555
2556 // Commit the bitmap slice:
2557 size_t slice = r->index() / _bitmap_regions_per_slice;
2558 size_t off = _bitmap_bytes_per_slice * slice;
2559 size_t len = _bitmap_bytes_per_slice;
2560 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2561 return false;
2562 }
2563 return true;
2564 }
2565
2566 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2567 shenandoah_assert_heaplocked();
2568
2569 // Bitmaps in special regions do not need uncommits
2570 if (_bitmap_region_special) {
2571 return true;
2572 }
2573
2574 if (is_bitmap_slice_committed(r, true)) {
2575 // Some other region from the group is still committed, meaning the bitmap
2576 // slice is should stay committed, exit right away.
2577 return true;
2578 }
2579
2580 // Uncommit the bitmap slice:
2581 size_t slice = r->index() / _bitmap_regions_per_slice;
2582 size_t off = _bitmap_bytes_per_slice * slice;
2583 size_t len = _bitmap_bytes_per_slice;
2584 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2585 return false;
2586 }
2587 return true;
2588 }
2589
2590 void ShenandoahHeap::safepoint_synchronize_begin() {
2591 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2592 SuspendibleThreadSet::synchronize();
2593 }
2594 }
2595
2596 void ShenandoahHeap::safepoint_synchronize_end() {
2597 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2598 SuspendibleThreadSet::desynchronize();
2599 }
2600 }
2601
2602 void ShenandoahHeap::vmop_entry_init_mark() {
2603 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2604 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2605 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2606
2607 try_inject_alloc_failure();
2608 VM_ShenandoahInitMark op;
2609 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2610 }
2611
2612 void ShenandoahHeap::vmop_entry_final_mark() {
2613 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2614 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2615 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2616
2617 try_inject_alloc_failure();
2618 VM_ShenandoahFinalMarkStartEvac op;
2619 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2620 }
2621
2622 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2623 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2624 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2625 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2626
2627 try_inject_alloc_failure();
2628 VM_ShenandoahInitUpdateRefs op;
2629 VMThread::execute(&op);
2630 }
2631
2632 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2633 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2634 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2635 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2636
2637 try_inject_alloc_failure();
2638 VM_ShenandoahFinalUpdateRefs op;
2639 VMThread::execute(&op);
2640 }
2641
2642 void ShenandoahHeap::vmop_entry_init_traversal() {
2643 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2644 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2645 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2646
2647 try_inject_alloc_failure();
2648 VM_ShenandoahInitTraversalGC op;
2649 VMThread::execute(&op);
2650 }
2651
2652 void ShenandoahHeap::vmop_entry_final_traversal() {
2653 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2654 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2655 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2656
2657 try_inject_alloc_failure();
2658 VM_ShenandoahFinalTraversalGC op;
2659 VMThread::execute(&op);
2660 }
2661
2662 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2663 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2664 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2665 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2666
2667 try_inject_alloc_failure();
2668 VM_ShenandoahFullGC op(cause);
2669 VMThread::execute(&op);
2670 }
2671
2672 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2673 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2674 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2675 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2676
2677 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2678 VMThread::execute(°enerated_gc);
2679 }
2680
2681 void ShenandoahHeap::entry_init_mark() {
2682 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2683 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2684 const char* msg = init_mark_event_message();
2685 GCTraceTime(Info, gc) time(msg, gc_timer());
2686 EventMark em("%s", msg);
2687
2688 ShenandoahWorkerScope scope(workers(),
2689 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2690 "init marking");
2691
2692 op_init_mark();
2693 }
2694
2695 void ShenandoahHeap::entry_final_mark() {
2696 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2697 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2698 const char* msg = final_mark_event_message();
2699 GCTraceTime(Info, gc) time(msg, gc_timer());
2700 EventMark em("%s", msg);
2701
2702 ShenandoahWorkerScope scope(workers(),
2703 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2704 "final marking");
2705
2706 op_final_mark();
2707 }
2708
2709 void ShenandoahHeap::entry_init_updaterefs() {
2710 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2711 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2712
2713 static const char* msg = "Pause Init Update Refs";
2714 GCTraceTime(Info, gc) time(msg, gc_timer());
2715 EventMark em("%s", msg);
2716
2717 // No workers used in this phase, no setup required
2718
2719 op_init_updaterefs();
2720 }
2721
2722 void ShenandoahHeap::entry_final_updaterefs() {
2723 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2724 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2725
2726 static const char* msg = "Pause Final Update Refs";
2727 GCTraceTime(Info, gc) time(msg, gc_timer());
2728 EventMark em("%s", msg);
2729
2730 ShenandoahWorkerScope scope(workers(),
2731 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2732 "final reference update");
2733
2734 op_final_updaterefs();
2735 }
2736
2737 void ShenandoahHeap::entry_init_traversal() {
2738 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2739 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2740
2741 static const char* msg = init_traversal_event_message();
2742 GCTraceTime(Info, gc) time(msg, gc_timer());
2743 EventMark em("%s", msg);
2744
2745 ShenandoahWorkerScope scope(workers(),
2746 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2747 "init traversal");
2748
2749 op_init_traversal();
2750 }
2751
2752 void ShenandoahHeap::entry_final_traversal() {
2753 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2754 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2755
2756 static const char* msg = final_traversal_event_message();
2757 GCTraceTime(Info, gc) time(msg, gc_timer());
2758 EventMark em("%s", msg);
2759
2760 ShenandoahWorkerScope scope(workers(),
2761 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2762 "final traversal");
2763
2764 op_final_traversal();
2765 }
2766
2767 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2768 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2769 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2770
2771 static const char* msg = "Pause Full";
2772 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2773 EventMark em("%s", msg);
2774
2775 ShenandoahWorkerScope scope(workers(),
2776 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2777 "full gc");
2778
2779 op_full(cause);
2780 }
2781
2782 void ShenandoahHeap::entry_degenerated(int point) {
2783 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2784 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2785
2786 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2787 const char* msg = degen_event_message(dpoint);
2788 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2789 EventMark em("%s", msg);
2790
2791 ShenandoahWorkerScope scope(workers(),
2792 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2793 "stw degenerated gc");
2794
2795 set_degenerated_gc_in_progress(true);
2796 op_degenerated(dpoint);
2797 set_degenerated_gc_in_progress(false);
2798 }
2799
2800 void ShenandoahHeap::entry_mark() {
2801 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2802
2803 const char* msg = conc_mark_event_message();
2804 GCTraceTime(Info, gc) time(msg);
2805 EventMark em("%s", msg);
2806
2807 ShenandoahWorkerScope scope(workers(),
2808 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2809 "concurrent marking");
2810
2811 try_inject_alloc_failure();
2812 op_mark();
2813 }
2814
2815 void ShenandoahHeap::entry_evac() {
2816 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2817 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2818
2819 static const char* msg = "Concurrent evacuation";
2820 GCTraceTime(Info, gc) time(msg);
2821 EventMark em("%s", msg);
2822
2823 ShenandoahWorkerScope scope(workers(),
2824 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2825 "concurrent evacuation");
2826
2827 try_inject_alloc_failure();
2828 op_conc_evac();
2829 }
2830
2831 void ShenandoahHeap::entry_updaterefs() {
2832 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2833
2834 static const char* msg = "Concurrent update references";
2835 GCTraceTime(Info, gc) time(msg);
2836 EventMark em("%s", msg);
2837
2838 ShenandoahWorkerScope scope(workers(),
2839 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2840 "concurrent reference update");
2841
2842 try_inject_alloc_failure();
2843 op_updaterefs();
2844 }
2845
2846 void ShenandoahHeap::entry_roots() {
2847 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots);
2848
2849 static const char* msg = "Concurrent roots processing";
2850 GCTraceTime(Info, gc) time(msg);
2851 EventMark em("%s", msg);
2852
2853 ShenandoahWorkerScope scope(workers(),
2854 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(),
2855 "concurrent root processing");
2856
2857 try_inject_alloc_failure();
2858 op_roots();
2859 }
2860
2861 void ShenandoahHeap::entry_cleanup() {
2862 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2863
2864 static const char* msg = "Concurrent cleanup";
2865 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2866 EventMark em("%s", msg);
2867
2868 // This phase does not use workers, no need for setup
2869
2870 try_inject_alloc_failure();
2871 op_cleanup();
2872 }
2873
2874 void ShenandoahHeap::entry_reset() {
2875 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2876
2877 static const char* msg = "Concurrent reset";
2878 GCTraceTime(Info, gc) time(msg);
2879 EventMark em("%s", msg);
2880
2881 ShenandoahWorkerScope scope(workers(),
2882 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2883 "concurrent reset");
2884
2885 try_inject_alloc_failure();
2886 op_reset();
2887 }
2888
2889 void ShenandoahHeap::entry_preclean() {
2890 if (ShenandoahPreclean && process_references()) {
2891 static const char* msg = "Concurrent precleaning";
2892 GCTraceTime(Info, gc) time(msg);
2893 EventMark em("%s", msg);
2894
2895 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2896
2897 ShenandoahWorkerScope scope(workers(),
2898 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2899 "concurrent preclean",
2900 /* check_workers = */ false);
2901
2902 try_inject_alloc_failure();
2903 op_preclean();
2904 }
2905 }
2906
2907 void ShenandoahHeap::entry_traversal() {
2908 static const char* msg = conc_traversal_event_message();
2909 GCTraceTime(Info, gc) time(msg);
2910 EventMark em("%s", msg);
2911
2912 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2913
2914 ShenandoahWorkerScope scope(workers(),
2915 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2916 "concurrent traversal");
2917
2918 try_inject_alloc_failure();
2919 op_traversal();
2920 }
2921
2922 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2923 static const char *msg = "Concurrent uncommit";
2924 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2925 EventMark em("%s", msg);
2926
2927 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2928
2929 op_uncommit(shrink_before);
2930 }
2931
2932 void ShenandoahHeap::try_inject_alloc_failure() {
2933 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2934 _inject_alloc_failure.set();
2935 os::naked_short_sleep(1);
2936 if (cancelled_gc()) {
2937 log_info(gc)("Allocation failure was successfully injected");
2938 }
2939 }
2940 }
2941
2942 bool ShenandoahHeap::should_inject_alloc_failure() {
2943 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2944 }
2945
2946 void ShenandoahHeap::initialize_serviceability() {
2947 _memory_pool = new ShenandoahMemoryPool(this);
2948 _cycle_memory_manager.add_pool(_memory_pool);
2949 _stw_memory_manager.add_pool(_memory_pool);
2950 }
2951
2952 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2953 GrowableArray<GCMemoryManager*> memory_managers(2);
2954 memory_managers.append(&_cycle_memory_manager);
2955 memory_managers.append(&_stw_memory_manager);
2956 return memory_managers;
2957 }
2958
2959 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2960 GrowableArray<MemoryPool*> memory_pools(1);
2961 memory_pools.append(_memory_pool);
2962 return memory_pools;
2963 }
2964
2965 MemoryUsage ShenandoahHeap::memory_usage() {
2966 return _memory_pool->get_memory_usage();
2967 }
2968
2969 void ShenandoahHeap::enter_evacuation() {
2970 _oom_evac_handler.enter_evacuation();
2971 }
2972
2973 void ShenandoahHeap::leave_evacuation() {
2974 _oom_evac_handler.leave_evacuation();
2975 }
2976
2977 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2978 _heap(ShenandoahHeap::heap()),
2979 _index(0) {}
2980
2981 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2982 _heap(heap),
2983 _index(0) {}
2984
2985 void ShenandoahRegionIterator::reset() {
2986 _index = 0;
2987 }
2988
2989 bool ShenandoahRegionIterator::has_next() const {
2990 return _index < _heap->num_regions();
2991 }
2992
2993 char ShenandoahHeap::gc_state() const {
2994 return _gc_state.raw_value();
2995 }
2996
2997 void ShenandoahHeap::deduplicate_string(oop str) {
2998 assert(java_lang_String::is_instance(str), "invariant");
2999
3000 if (ShenandoahStringDedup::is_enabled()) {
3001 ShenandoahStringDedup::deduplicate(str);
3002 }
3003 }
3004
3005 const char* ShenandoahHeap::init_mark_event_message() const {
3006 assert(!has_forwarded_objects(), "Should not have forwarded objects here");
3007
3008 bool proc_refs = process_references();
3009 bool unload_cls = unload_classes();
3010
3011 if (proc_refs && unload_cls) {
3012 return "Pause Init Mark (process weakrefs) (unload classes)";
3013 } else if (proc_refs) {
3014 return "Pause Init Mark (process weakrefs)";
3015 } else if (unload_cls) {
3016 return "Pause Init Mark (unload classes)";
3017 } else {
3018 return "Pause Init Mark";
3019 }
3020 }
3021
3022 const char* ShenandoahHeap::final_mark_event_message() const {
3023 assert(!has_forwarded_objects(), "Should not have forwarded objects here");
3024
3025 bool proc_refs = process_references();
3026 bool unload_cls = unload_classes();
3027
3028 if (proc_refs && unload_cls) {
3029 return "Pause Final Mark (process weakrefs) (unload classes)";
3030 } else if (proc_refs) {
3031 return "Pause Final Mark (process weakrefs)";
3032 } else if (unload_cls) {
3033 return "Pause Final Mark (unload classes)";
3034 } else {
3035 return "Pause Final Mark";
3036 }
3037 }
3038
3039 const char* ShenandoahHeap::conc_mark_event_message() const {
3040 assert(!has_forwarded_objects(), "Should not have forwarded objects here");
3041
3042 bool proc_refs = process_references();
3043 bool unload_cls = unload_classes();
3044
3045 if (proc_refs && unload_cls) {
3046 return "Concurrent marking (process weakrefs) (unload classes)";
3047 } else if (proc_refs) {
3048 return "Concurrent marking (process weakrefs)";
3049 } else if (unload_cls) {
3050 return "Concurrent marking (unload classes)";
3051 } else {
3052 return "Concurrent marking";
3053 }
3054 }
3055
3056 const char* ShenandoahHeap::init_traversal_event_message() const {
3057 bool proc_refs = process_references();
3058 bool unload_cls = unload_classes();
3059
3060 if (proc_refs && unload_cls) {
3061 return "Pause Init Traversal (process weakrefs) (unload classes)";
3062 } else if (proc_refs) {
3063 return "Pause Init Traversal (process weakrefs)";
3064 } else if (unload_cls) {
3065 return "Pause Init Traversal (unload classes)";
3066 } else {
3067 return "Pause Init Traversal";
3068 }
3069 }
3070
3071 const char* ShenandoahHeap::final_traversal_event_message() const {
3072 bool proc_refs = process_references();
3073 bool unload_cls = unload_classes();
3074
3075 if (proc_refs && unload_cls) {
3076 return "Pause Final Traversal (process weakrefs) (unload classes)";
3077 } else if (proc_refs) {
3078 return "Pause Final Traversal (process weakrefs)";
3079 } else if (unload_cls) {
3080 return "Pause Final Traversal (unload classes)";
3081 } else {
3082 return "Pause Final Traversal";
3083 }
3084 }
3085
3086 const char* ShenandoahHeap::conc_traversal_event_message() const {
3087 bool proc_refs = process_references();
3088 bool unload_cls = unload_classes();
3089
3090 if (proc_refs && unload_cls) {
3091 return "Concurrent Traversal (process weakrefs) (unload classes)";
3092 } else if (proc_refs) {
3093 return "Concurrent Traversal (process weakrefs)";
3094 } else if (unload_cls) {
3095 return "Concurrent Traversal (unload classes)";
3096 } else {
3097 return "Concurrent Traversal";
3098 }
3099 }
3100
3101 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
3102 switch (point) {
3103 case _degenerated_unset:
3104 return "Pause Degenerated GC (<UNSET>)";
3105 case _degenerated_traversal:
3106 return "Pause Degenerated GC (Traversal)";
3107 case _degenerated_outside_cycle:
3108 return "Pause Degenerated GC (Outside of Cycle)";
3109 case _degenerated_mark:
3110 return "Pause Degenerated GC (Mark)";
3111 case _degenerated_evac:
3112 return "Pause Degenerated GC (Evacuation)";
3113 case _degenerated_updaterefs:
3114 return "Pause Degenerated GC (Update Refs)";
3115 default:
3116 ShouldNotReachHere();
3117 return "ERROR";
3118 }
3119 }
3120
3121 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
3122 #ifdef ASSERT
3123 assert(_liveness_cache != NULL, "sanity");
3124 assert(worker_id < _max_workers, "sanity");
3125 for (uint i = 0; i < num_regions(); i++) {
3126 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
3127 }
3128 #endif
3129 return _liveness_cache[worker_id];
3130 }
3131
3132 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
3133 assert(worker_id < _max_workers, "sanity");
3134 assert(_liveness_cache != NULL, "sanity");
3135 jushort* ld = _liveness_cache[worker_id];
3136 for (uint i = 0; i < num_regions(); i++) {
3137 ShenandoahHeapRegion* r = get_region(i);
3138 jushort live = ld[i];
3139 if (live > 0) {
3140 r->increase_live_data_gc_words(live);
3141 ld[i] = 0;
3142 }
3143 }
3144 }