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/shenandoahAllocTracker.hpp"
38 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
39 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
40 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
41 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
42 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
43 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp"
44 #include "gc/shenandoah/shenandoahControlThread.hpp"
45 #include "gc/shenandoah/shenandoahFreeSet.hpp"
46 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
47 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
48 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
49 #include "gc/shenandoah/shenandoahHeapRegionSet.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/shenandoahParallelCleaning.inline.hpp"
59 #include "gc/shenandoah/shenandoahPassiveMode.hpp"
60 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
61 #include "gc/shenandoah/shenandoahStringDedup.hpp"
62 #include "gc/shenandoah/shenandoahTaskqueue.hpp"
63 #include "gc/shenandoah/shenandoahTraversalMode.hpp"
64 #include "gc/shenandoah/shenandoahUtils.hpp"
65 #include "gc/shenandoah/shenandoahVerifier.hpp"
66 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
67 #include "gc/shenandoah/shenandoahVMOperations.hpp"
68 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
69 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
70 #if INCLUDE_JFR
71 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
72 #endif
73
74 #include "memory/metaspace.hpp"
75 #include "oops/compressedOops.inline.hpp"
76 #include "runtime/atomic.hpp"
77 #include "runtime/globals.hpp"
78 #include "runtime/interfaceSupport.inline.hpp"
79 #include "runtime/orderAccess.hpp"
80 #include "runtime/safepointMechanism.hpp"
81 #include "runtime/vmThread.hpp"
82 #include "services/mallocTracker.hpp"
83 #include "utilities/powerOfTwo.hpp"
84
85 #ifdef ASSERT
86 template <class T>
87 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
88 T o = RawAccess<>::oop_load(p);
89 if (! CompressedOops::is_null(o)) {
90 oop obj = CompressedOops::decode_not_null(o);
91 shenandoah_assert_not_forwarded(p, obj);
92 }
93 }
94
95 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
96 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
97 #endif
98
99 class ShenandoahPretouchHeapTask : public AbstractGangTask {
100 private:
101 ShenandoahRegionIterator _regions;
102 const size_t _page_size;
103 public:
104 ShenandoahPretouchHeapTask(size_t page_size) :
105 AbstractGangTask("Shenandoah Pretouch Heap"),
106 _page_size(page_size) {}
107
108 virtual void work(uint worker_id) {
109 ShenandoahHeapRegion* r = _regions.next();
110 while (r != NULL) {
111 os::pretouch_memory(r->bottom(), r->end(), _page_size);
112 r = _regions.next();
113 }
114 }
115 };
116
117 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
118 private:
119 ShenandoahRegionIterator _regions;
120 char* _bitmap_base;
121 const size_t _bitmap_size;
122 const size_t _page_size;
123 public:
124 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
125 AbstractGangTask("Shenandoah Pretouch Bitmap"),
126 _bitmap_base(bitmap_base),
127 _bitmap_size(bitmap_size),
128 _page_size(page_size) {}
129
130 virtual void work(uint worker_id) {
131 ShenandoahHeapRegion* r = _regions.next();
132 while (r != NULL) {
133 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
134 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
135 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
136
137 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
138
139 r = _regions.next();
140 }
141 }
142 };
143
144 jint ShenandoahHeap::initialize() {
145 initialize_heuristics();
146
147 //
148 // Figure out heap sizing
149 //
150
151 size_t init_byte_size = InitialHeapSize;
152 size_t min_byte_size = MinHeapSize;
153 size_t max_byte_size = MaxHeapSize;
154 size_t heap_alignment = HeapAlignment;
155
156 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
157
158 if (ShenandoahAlwaysPreTouch) {
159 // Enabled pre-touch means the entire heap is committed right away.
160 init_byte_size = max_byte_size;
161 }
162
163 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
164 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
165
166 _num_regions = ShenandoahHeapRegion::region_count();
167
168 size_t num_committed_regions = init_byte_size / reg_size_bytes;
169 num_committed_regions = MIN2(num_committed_regions, _num_regions);
170 assert(num_committed_regions <= _num_regions, "sanity");
171 _initial_size = num_committed_regions * reg_size_bytes;
172
173 size_t num_min_regions = min_byte_size / reg_size_bytes;
174 num_min_regions = MIN2(num_min_regions, _num_regions);
175 assert(num_min_regions <= _num_regions, "sanity");
176 _minimum_size = num_min_regions * reg_size_bytes;
177
178 _committed = _initial_size;
179
180 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
181 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
182
183 //
184 // Reserve and commit memory for heap
185 //
186
187 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
188 initialize_reserved_region(heap_rs);
189 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
190 _heap_region_special = heap_rs.special();
191
192 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
193 "Misaligned heap: " PTR_FORMAT, p2i(base()));
194
195 #if SHENANDOAH_OPTIMIZED_OBJTASK
196 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits.
197 // Fail if we ever attempt to address more than we can.
198 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) {
199 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n"
200 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n"
201 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).",
202 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable());
203 vm_exit_during_initialization("Fatal Error", buf);
204 }
205 #endif
206
207 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
208 if (!_heap_region_special) {
209 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
210 "Cannot commit heap memory");
211 }
212
213 //
214 // Reserve and commit memory for bitmap(s)
215 //
216
217 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
218 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
219
220 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
221
222 guarantee(bitmap_bytes_per_region != 0,
223 "Bitmap bytes per region should not be zero");
224 guarantee(is_power_of_2(bitmap_bytes_per_region),
225 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
226
227 if (bitmap_page_size > bitmap_bytes_per_region) {
228 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
229 _bitmap_bytes_per_slice = bitmap_page_size;
230 } else {
231 _bitmap_regions_per_slice = 1;
232 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
233 }
234
235 guarantee(_bitmap_regions_per_slice >= 1,
236 "Should have at least one region per slice: " SIZE_FORMAT,
237 _bitmap_regions_per_slice);
238
239 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
240 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
241 _bitmap_bytes_per_slice, bitmap_page_size);
242
243 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
244 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
245 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
246 _bitmap_region_special = bitmap.special();
247
248 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
249 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
250 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
251 if (!_bitmap_region_special) {
252 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
253 "Cannot commit bitmap memory");
254 }
255
256 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
257
258 if (ShenandoahVerify) {
259 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
260 if (!verify_bitmap.special()) {
261 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
262 "Cannot commit verification bitmap memory");
263 }
264 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
265 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
266 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
267 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
268 }
269
270 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
271 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
272 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
273 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
274 _aux_bitmap_region_special = aux_bitmap.special();
275 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
276
277 //
278 // Create regions and region sets
279 //
280
281 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
282 _free_set = new ShenandoahFreeSet(this, _num_regions);
283 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
284
285 {
286 ShenandoahHeapLocker locker(lock());
287
288 size_t size_words = ShenandoahHeapRegion::region_size_words();
289
290 for (size_t i = 0; i < _num_regions; i++) {
291 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
292 bool is_committed = i < num_committed_regions;
293 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
294
295 _marking_context->initialize_top_at_mark_start(r);
296 _regions[i] = r;
297 assert(!collection_set()->is_in(i), "New region should not be in collection set");
298 }
299
300 // Initialize to complete
301 _marking_context->mark_complete();
302
303 _free_set->rebuild();
304 }
305
306 if (ShenandoahAlwaysPreTouch) {
307 assert(!AlwaysPreTouch, "Should have been overridden");
308
309 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
310 // before initialize() below zeroes it with initializing thread. For any given region,
311 // we touch the region and the corresponding bitmaps from the same thread.
312 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
313
314 size_t pretouch_heap_page_size = heap_page_size;
315 size_t pretouch_bitmap_page_size = bitmap_page_size;
316
317 #ifdef LINUX
318 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
319 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
320 // them into huge one. Therefore, we need to pretouch with smaller pages.
321 if (UseTransparentHugePages) {
322 pretouch_heap_page_size = (size_t)os::vm_page_size();
323 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
324 }
325 #endif
326
327 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
328 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
329
330 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
331 _num_regions, pretouch_bitmap_page_size);
332 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
333 _workers->run_task(&bcl);
334
335 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
336 _num_regions, pretouch_heap_page_size);
337 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
338 _workers->run_task(&hcl);
339 }
340
341 //
342 // Initialize the rest of GC subsystems
343 //
344
345 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
346 for (uint worker = 0; worker < _max_workers; worker++) {
347 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
348 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
349 }
350
351 // There should probably be Shenandoah-specific options for these,
352 // just as there are G1-specific options.
353 {
354 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set();
355 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold
356 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent
357 }
358
359 _monitoring_support = new ShenandoahMonitoringSupport(this);
360 _phase_timings = new ShenandoahPhaseTimings();
361 ShenandoahStringDedup::initialize();
362 ShenandoahCodeRoots::initialize();
363
364 if (ShenandoahAllocationTrace) {
365 _alloc_tracker = new ShenandoahAllocTracker();
366 }
367
368 if (ShenandoahPacing) {
369 _pacer = new ShenandoahPacer(this);
370 _pacer->setup_for_idle();
371 } else {
372 _pacer = NULL;
373 }
374
375 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ?
376 new ShenandoahTraversalGC(this, _num_regions) :
377 NULL;
378
379 _control_thread = new ShenandoahControlThread();
380
381 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
382 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
383 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
384 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
385 );
386
387 log_info(gc, init)("Safepointing mechanism: %s",
388 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
389 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
390
391 return JNI_OK;
392 }
393
394 void ShenandoahHeap::initialize_heuristics() {
395 if (ShenandoahGCMode != NULL) {
396 if (strcmp(ShenandoahGCMode, "traversal") == 0) {
397 _gc_mode = new ShenandoahTraversalMode();
398 } else if (strcmp(ShenandoahGCMode, "normal") == 0) {
399 _gc_mode = new ShenandoahNormalMode();
400 } else if (strcmp(ShenandoahGCMode, "passive") == 0) {
401 _gc_mode = new ShenandoahPassiveMode();
402 } else {
403 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option");
404 }
405 } else {
406 ShouldNotReachHere();
407 }
408 _gc_mode->initialize_flags();
409 _heuristics = _gc_mode->initialize_heuristics();
410
411 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
412 vm_exit_during_initialization(
413 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
414 _heuristics->name()));
415 }
416 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
417 vm_exit_during_initialization(
418 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
419 _heuristics->name()));
420 }
421 log_info(gc, init)("Shenandoah heuristics: %s",
422 _heuristics->name());
423 }
424
425 #ifdef _MSC_VER
426 #pragma warning( push )
427 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
428 #endif
429
430 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
431 CollectedHeap(),
432 _initial_size(0),
433 _used(0),
434 _committed(0),
435 _bytes_allocated_since_gc_start(0),
436 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
437 _workers(NULL),
438 _safepoint_workers(NULL),
439 _heap_region_special(false),
440 _num_regions(0),
441 _regions(NULL),
442 _update_refs_iterator(this),
443 _control_thread(NULL),
444 _shenandoah_policy(policy),
445 _heuristics(NULL),
446 _free_set(NULL),
447 _scm(new ShenandoahConcurrentMark()),
448 _traversal_gc(NULL),
449 _full_gc(new ShenandoahMarkCompact()),
450 _pacer(NULL),
451 _verifier(NULL),
452 _alloc_tracker(NULL),
453 _phase_timings(NULL),
454 _monitoring_support(NULL),
455 _memory_pool(NULL),
456 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
457 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
458 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
459 _soft_ref_policy(),
460 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
461 _ref_processor(NULL),
462 _marking_context(NULL),
463 _bitmap_size(0),
464 _bitmap_regions_per_slice(0),
465 _bitmap_bytes_per_slice(0),
466 _bitmap_region_special(false),
467 _aux_bitmap_region_special(false),
468 _liveness_cache(NULL),
469 _collection_set(NULL)
470 {
471 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
472 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
473
474 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
475
476 _max_workers = MAX2(_max_workers, 1U);
477 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
478 /* are_GC_task_threads */ true,
479 /* are_ConcurrentGC_threads */ true);
480 if (_workers == NULL) {
481 vm_exit_during_initialization("Failed necessary allocation.");
482 } else {
483 _workers->initialize_workers();
484 }
485
486 if (ShenandoahParallelSafepointThreads > 1) {
487 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
488 ShenandoahParallelSafepointThreads,
489 /* are_GC_task_threads */ false,
490 /* are_ConcurrentGC_threads */ false);
491 _safepoint_workers->initialize_workers();
492 }
493 }
494
495 #ifdef _MSC_VER
496 #pragma warning( pop )
497 #endif
498
499 class ShenandoahResetBitmapTask : public AbstractGangTask {
500 private:
501 ShenandoahRegionIterator _regions;
502
503 public:
504 ShenandoahResetBitmapTask() :
505 AbstractGangTask("Parallel Reset Bitmap Task") {}
506
507 void work(uint worker_id) {
508 ShenandoahHeapRegion* region = _regions.next();
509 ShenandoahHeap* heap = ShenandoahHeap::heap();
510 ShenandoahMarkingContext* const ctx = heap->marking_context();
511 while (region != NULL) {
512 if (heap->is_bitmap_slice_committed(region)) {
513 ctx->clear_bitmap(region);
514 }
515 region = _regions.next();
516 }
517 }
518 };
519
520 void ShenandoahHeap::reset_mark_bitmap() {
521 assert_gc_workers(_workers->active_workers());
522 mark_incomplete_marking_context();
523
524 ShenandoahResetBitmapTask task;
525 _workers->run_task(&task);
526 }
527
528 void ShenandoahHeap::print_on(outputStream* st) const {
529 st->print_cr("Shenandoah Heap");
530 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used",
531 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()),
532 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()),
533 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used()));
534 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions",
535 num_regions(),
536 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()),
537 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes()));
538
539 st->print("Status: ");
540 if (has_forwarded_objects()) st->print("has forwarded objects, ");
541 if (is_concurrent_mark_in_progress()) st->print("marking, ");
542 if (is_evacuation_in_progress()) st->print("evacuating, ");
543 if (is_update_refs_in_progress()) st->print("updating refs, ");
544 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
545 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
546 if (is_full_gc_in_progress()) st->print("full gc, ");
547 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
548 if (is_concurrent_root_in_progress()) st->print("concurrent roots, ");
549
550 if (cancelled_gc()) {
551 st->print("cancelled");
552 } else {
553 st->print("not cancelled");
554 }
555 st->cr();
556
557 st->print_cr("Reserved region:");
558 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
559 p2i(reserved_region().start()),
560 p2i(reserved_region().end()));
561
562 ShenandoahCollectionSet* cset = collection_set();
563 st->print_cr("Collection set:");
564 if (cset != NULL) {
565 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
566 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
567 } else {
568 st->print_cr(" (NULL)");
569 }
570
571 st->cr();
572 MetaspaceUtils::print_on(st);
573
574 if (Verbose) {
575 print_heap_regions_on(st);
576 }
577 }
578
579 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
580 public:
581 void do_thread(Thread* thread) {
582 assert(thread != NULL, "Sanity");
583 assert(thread->is_Worker_thread(), "Only worker thread expected");
584 ShenandoahThreadLocalData::initialize_gclab(thread);
585 }
586 };
587
588 void ShenandoahHeap::post_initialize() {
589 CollectedHeap::post_initialize();
590 MutexLocker ml(Threads_lock);
591
592 ShenandoahInitWorkerGCLABClosure init_gclabs;
593 _workers->threads_do(&init_gclabs);
594
595 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
596 // Now, we will let WorkGang to initialize gclab when new worker is created.
597 _workers->set_initialize_gclab();
598
599 _scm->initialize(_max_workers);
600 _full_gc->initialize(_gc_timer);
601
602 ref_processing_init();
603
604 _heuristics->initialize();
605
606 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers());
607 }
608
609 size_t ShenandoahHeap::used() const {
610 return Atomic::load_acquire(&_used);
611 }
612
613 size_t ShenandoahHeap::committed() const {
614 OrderAccess::acquire();
615 return _committed;
616 }
617
618 void ShenandoahHeap::increase_committed(size_t bytes) {
619 assert_heaplock_or_safepoint();
620 _committed += bytes;
621 }
622
623 void ShenandoahHeap::decrease_committed(size_t bytes) {
624 assert_heaplock_or_safepoint();
625 _committed -= bytes;
626 }
627
628 void ShenandoahHeap::increase_used(size_t bytes) {
629 Atomic::add(&_used, bytes);
630 }
631
632 void ShenandoahHeap::set_used(size_t bytes) {
633 Atomic::release_store_fence(&_used, bytes);
634 }
635
636 void ShenandoahHeap::decrease_used(size_t bytes) {
637 assert(used() >= bytes, "never decrease heap size by more than we've left");
638 Atomic::sub(&_used, bytes);
639 }
640
641 void ShenandoahHeap::increase_allocated(size_t bytes) {
642 Atomic::add(&_bytes_allocated_since_gc_start, bytes);
643 }
644
645 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
646 size_t bytes = words * HeapWordSize;
647 if (!waste) {
648 increase_used(bytes);
649 }
650 increase_allocated(bytes);
651 if (ShenandoahPacing) {
652 control_thread()->pacing_notify_alloc(words);
653 if (waste) {
654 pacer()->claim_for_alloc(words, true);
655 }
656 }
657 }
658
659 size_t ShenandoahHeap::capacity() const {
660 return committed();
661 }
662
663 size_t ShenandoahHeap::max_capacity() const {
664 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
665 }
666
667 size_t ShenandoahHeap::min_capacity() const {
668 return _minimum_size;
669 }
670
671 size_t ShenandoahHeap::initial_capacity() const {
672 return _initial_size;
673 }
674
675 bool ShenandoahHeap::is_in(const void* p) const {
676 HeapWord* heap_base = (HeapWord*) base();
677 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
678 return p >= heap_base && p < last_region_end;
679 }
680
681 void ShenandoahHeap::op_uncommit(double shrink_before) {
682 assert (ShenandoahUncommit, "should be enabled");
683
684 // Application allocates from the beginning of the heap, and GC allocates at
685 // the end of it. It is more efficient to uncommit from the end, so that applications
686 // could enjoy the near committed regions. GC allocations are much less frequent,
687 // and therefore can accept the committing costs.
688
689 size_t count = 0;
690 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
691 ShenandoahHeapRegion* r = get_region(i - 1);
692 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
693 ShenandoahHeapLocker locker(lock());
694 if (r->is_empty_committed()) {
695 // Do not uncommit below minimal capacity
696 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
697 break;
698 }
699
700 r->make_uncommitted();
701 count++;
702 }
703 }
704 SpinPause(); // allow allocators to take the lock
705 }
706
707 if (count > 0) {
708 control_thread()->notify_heap_changed();
709 }
710 }
711
712 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
713 // New object should fit the GCLAB size
714 size_t min_size = MAX2(size, PLAB::min_size());
715
716 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
717 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
718 new_size = MIN2(new_size, PLAB::max_size());
719 new_size = MAX2(new_size, PLAB::min_size());
720
721 // Record new heuristic value even if we take any shortcut. This captures
722 // the case when moderately-sized objects always take a shortcut. At some point,
723 // heuristics should catch up with them.
724 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
725
726 if (new_size < size) {
727 // New size still does not fit the object. Fall back to shared allocation.
728 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
729 return NULL;
730 }
731
732 // Retire current GCLAB, and allocate a new one.
733 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
734 gclab->retire();
735
736 size_t actual_size = 0;
737 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
738 if (gclab_buf == NULL) {
739 return NULL;
740 }
741
742 assert (size <= actual_size, "allocation should fit");
743
744 if (ZeroTLAB) {
745 // ..and clear it.
746 Copy::zero_to_words(gclab_buf, actual_size);
747 } else {
748 // ...and zap just allocated object.
749 #ifdef ASSERT
750 // Skip mangling the space corresponding to the object header to
751 // ensure that the returned space is not considered parsable by
752 // any concurrent GC thread.
753 size_t hdr_size = oopDesc::header_size();
754 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
755 #endif // ASSERT
756 }
757 gclab->set_buf(gclab_buf, actual_size);
758 return gclab->allocate(size);
759 }
760
761 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
762 size_t requested_size,
763 size_t* actual_size) {
764 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
765 HeapWord* res = allocate_memory(req);
766 if (res != NULL) {
767 *actual_size = req.actual_size();
768 } else {
769 *actual_size = 0;
770 }
771 return res;
772 }
773
774 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
775 size_t word_size,
776 size_t* actual_size) {
777 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
778 HeapWord* res = allocate_memory(req);
779 if (res != NULL) {
780 *actual_size = req.actual_size();
781 } else {
782 *actual_size = 0;
783 }
784 return res;
785 }
786
787 ShenandoahHeap* ShenandoahHeap::heap() {
788 CollectedHeap* heap = Universe::heap();
789 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
790 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
791 return (ShenandoahHeap*) heap;
792 }
793
794 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
795 CollectedHeap* heap = Universe::heap();
796 return (ShenandoahHeap*) heap;
797 }
798
799 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
800 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
801
802 intptr_t pacer_epoch = 0;
803 bool in_new_region = false;
804 HeapWord* result = NULL;
805
806 if (req.is_mutator_alloc()) {
807 if (ShenandoahPacing) {
808 pacer()->pace_for_alloc(req.size());
809 pacer_epoch = pacer()->epoch();
810 }
811
812 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
813 result = allocate_memory_under_lock(req, in_new_region);
814 }
815
816 // Allocation failed, block until control thread reacted, then retry allocation.
817 //
818 // It might happen that one of the threads requesting allocation would unblock
819 // way later after GC happened, only to fail the second allocation, because
820 // other threads have already depleted the free storage. In this case, a better
821 // strategy is to try again, as long as GC makes progress.
822 //
823 // Then, we need to make sure the allocation was retried after at least one
824 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
825
826 size_t tries = 0;
827
828 while (result == NULL && _progress_last_gc.is_set()) {
829 tries++;
830 control_thread()->handle_alloc_failure(req.size());
831 result = allocate_memory_under_lock(req, in_new_region);
832 }
833
834 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
835 tries++;
836 control_thread()->handle_alloc_failure(req.size());
837 result = allocate_memory_under_lock(req, in_new_region);
838 }
839
840 } else {
841 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
842 result = allocate_memory_under_lock(req, in_new_region);
843 // Do not call handle_alloc_failure() here, because we cannot block.
844 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
845 }
846
847 if (in_new_region) {
848 control_thread()->notify_heap_changed();
849 }
850
851 if (result != NULL) {
852 size_t requested = req.size();
853 size_t actual = req.actual_size();
854
855 assert (req.is_lab_alloc() || (requested == actual),
856 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
857 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
858
859 if (req.is_mutator_alloc()) {
860 notify_mutator_alloc_words(actual, false);
861
862 // If we requested more than we were granted, give the rest back to pacer.
863 // This only matters if we are in the same pacing epoch: do not try to unpace
864 // over the budget for the other phase.
865 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
866 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
867 }
868 } else {
869 increase_used(actual*HeapWordSize);
870 }
871 }
872
873 return result;
874 }
875
876 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
877 ShenandoahHeapLocker locker(lock());
878 return _free_set->allocate(req, in_new_region);
879 }
880
881 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
882 bool* gc_overhead_limit_was_exceeded) {
883 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
884 return allocate_memory(req);
885 }
886
887 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
888 size_t size,
889 Metaspace::MetadataType mdtype) {
890 MetaWord* result;
891
892 // Inform metaspace OOM to GC heuristics if class unloading is possible.
893 if (heuristics()->can_unload_classes()) {
894 ShenandoahHeuristics* h = heuristics();
895 h->record_metaspace_oom();
896 }
897
898 // Expand and retry allocation
899 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
900 if (result != NULL) {
901 return result;
902 }
903
904 // Start full GC
905 collect(GCCause::_metadata_GC_clear_soft_refs);
906
907 // Retry allocation
908 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
909 if (result != NULL) {
910 return result;
911 }
912
913 // Expand and retry allocation
914 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
915 if (result != NULL) {
916 return result;
917 }
918
919 // Out of memory
920 return NULL;
921 }
922
923 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
924 private:
925 ShenandoahHeap* const _heap;
926 Thread* const _thread;
927 public:
928 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
929 _heap(heap), _thread(Thread::current()) {}
930
931 void do_object(oop p) {
932 shenandoah_assert_marked(NULL, p);
933 if (!p->is_forwarded()) {
934 _heap->evacuate_object(p, _thread);
935 }
936 }
937 };
938
939 class ShenandoahEvacuationTask : public AbstractGangTask {
940 private:
941 ShenandoahHeap* const _sh;
942 ShenandoahCollectionSet* const _cs;
943 bool _concurrent;
944 public:
945 ShenandoahEvacuationTask(ShenandoahHeap* sh,
946 ShenandoahCollectionSet* cs,
947 bool concurrent) :
948 AbstractGangTask("Parallel Evacuation Task"),
949 _sh(sh),
950 _cs(cs),
951 _concurrent(concurrent)
952 {}
953
954 void work(uint worker_id) {
955 if (_concurrent) {
956 ShenandoahConcurrentWorkerSession worker_session(worker_id);
957 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
958 ShenandoahEvacOOMScope oom_evac_scope;
959 do_work();
960 } else {
961 ShenandoahParallelWorkerSession worker_session(worker_id);
962 ShenandoahEvacOOMScope oom_evac_scope;
963 do_work();
964 }
965 }
966
967 private:
968 void do_work() {
969 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
970 ShenandoahHeapRegion* r;
971 while ((r =_cs->claim_next()) != NULL) {
972 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->region_number());
973 _sh->marked_object_iterate(r, &cl);
974
975 if (ShenandoahPacing) {
976 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
977 }
978
979 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
980 break;
981 }
982 }
983 }
984 };
985
986 void ShenandoahHeap::trash_cset_regions() {
987 ShenandoahHeapLocker locker(lock());
988
989 ShenandoahCollectionSet* set = collection_set();
990 ShenandoahHeapRegion* r;
991 set->clear_current_index();
992 while ((r = set->next()) != NULL) {
993 r->make_trash();
994 }
995 collection_set()->clear();
996 }
997
998 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
999 st->print_cr("Heap Regions:");
1000 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1001 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1002 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1003 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1004
1005 for (size_t i = 0; i < num_regions(); i++) {
1006 get_region(i)->print_on(st);
1007 }
1008 }
1009
1010 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1011 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1012
1013 oop humongous_obj = oop(start->bottom());
1014 size_t size = humongous_obj->size();
1015 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1016 size_t index = start->region_number() + required_regions - 1;
1017
1018 assert(!start->has_live(), "liveness must be zero");
1019
1020 for(size_t i = 0; i < required_regions; i++) {
1021 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1022 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1023 ShenandoahHeapRegion* region = get_region(index --);
1024
1025 assert(region->is_humongous(), "expect correct humongous start or continuation");
1026 assert(!region->is_cset(), "Humongous region should not be in collection set");
1027
1028 region->make_trash_immediate();
1029 }
1030 }
1031
1032 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1033 public:
1034 void do_thread(Thread* thread) {
1035 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1036 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1037 gclab->retire();
1038 }
1039 };
1040
1041 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1042 if (UseTLAB) {
1043 CollectedHeap::ensure_parsability(retire_tlabs);
1044 }
1045 ShenandoahRetireGCLABClosure cl;
1046 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1047 cl.do_thread(t);
1048 }
1049 workers()->threads_do(&cl);
1050 }
1051
1052 void ShenandoahHeap::resize_tlabs() {
1053 CollectedHeap::resize_all_tlabs();
1054 }
1055
1056 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1057 private:
1058 ShenandoahRootEvacuator* _rp;
1059
1060 public:
1061 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1062 AbstractGangTask("Shenandoah evacuate and update roots"),
1063 _rp(rp) {}
1064
1065 void work(uint worker_id) {
1066 ShenandoahParallelWorkerSession worker_session(worker_id);
1067 ShenandoahEvacOOMScope oom_evac_scope;
1068 ShenandoahEvacuateUpdateRootsClosure<> cl;
1069 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1070 _rp->roots_do(worker_id, &cl);
1071 }
1072 };
1073
1074 void ShenandoahHeap::evacuate_and_update_roots() {
1075 #if COMPILER2_OR_JVMCI
1076 DerivedPointerTable::clear();
1077 #endif
1078 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1079 {
1080 // Include concurrent roots if current cycle can not process those roots concurrently
1081 ShenandoahRootEvacuator rp(workers()->active_workers(),
1082 ShenandoahPhaseTimings::init_evac,
1083 !ShenandoahConcurrentRoots::should_do_concurrent_roots(),
1084 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1085 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1086 workers()->run_task(&roots_task);
1087 }
1088
1089 #if COMPILER2_OR_JVMCI
1090 DerivedPointerTable::update_pointers();
1091 #endif
1092 }
1093
1094 // Returns size in bytes
1095 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1096 if (ShenandoahElasticTLAB) {
1097 // With Elastic TLABs, return the max allowed size, and let the allocation path
1098 // figure out the safe size for current allocation.
1099 return ShenandoahHeapRegion::max_tlab_size_bytes();
1100 } else {
1101 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1102 }
1103 }
1104
1105 size_t ShenandoahHeap::max_tlab_size() const {
1106 // Returns size in words
1107 return ShenandoahHeapRegion::max_tlab_size_words();
1108 }
1109
1110 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1111 public:
1112 void do_thread(Thread* thread) {
1113 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1114 gclab->retire();
1115 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1116 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1117 }
1118 }
1119 };
1120
1121 void ShenandoahHeap::retire_and_reset_gclabs() {
1122 ShenandoahRetireAndResetGCLABClosure cl;
1123 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1124 cl.do_thread(t);
1125 }
1126 workers()->threads_do(&cl);
1127 }
1128
1129 void ShenandoahHeap::collect(GCCause::Cause cause) {
1130 control_thread()->request_gc(cause);
1131 }
1132
1133 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1134 //assert(false, "Shouldn't need to do full collections");
1135 }
1136
1137 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1138 Space* sp = heap_region_containing(addr);
1139 if (sp != NULL) {
1140 return sp->block_start(addr);
1141 }
1142 return NULL;
1143 }
1144
1145 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1146 Space* sp = heap_region_containing(addr);
1147 return sp->block_is_obj(addr);
1148 }
1149
1150 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const {
1151 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr);
1152 }
1153
1154 jlong ShenandoahHeap::millis_since_last_gc() {
1155 double v = heuristics()->time_since_last_gc() * 1000;
1156 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1157 return (jlong)v;
1158 }
1159
1160 void ShenandoahHeap::prepare_for_verify() {
1161 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1162 make_parsable(false);
1163 }
1164 }
1165
1166 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1167 workers()->print_worker_threads_on(st);
1168 if (ShenandoahStringDedup::is_enabled()) {
1169 ShenandoahStringDedup::print_worker_threads_on(st);
1170 }
1171 }
1172
1173 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1174 workers()->threads_do(tcl);
1175 if (_safepoint_workers != NULL) {
1176 _safepoint_workers->threads_do(tcl);
1177 }
1178 if (ShenandoahStringDedup::is_enabled()) {
1179 ShenandoahStringDedup::threads_do(tcl);
1180 }
1181 }
1182
1183 void ShenandoahHeap::print_tracing_info() const {
1184 LogTarget(Info, gc, stats) lt;
1185 if (lt.is_enabled()) {
1186 ResourceMark rm;
1187 LogStream ls(lt);
1188
1189 phase_timings()->print_on(&ls);
1190
1191 ls.cr();
1192 ls.cr();
1193
1194 shenandoah_policy()->print_gc_stats(&ls);
1195
1196 ls.cr();
1197 ls.cr();
1198
1199 if (ShenandoahPacing) {
1200 pacer()->print_on(&ls);
1201 }
1202
1203 ls.cr();
1204 ls.cr();
1205
1206 if (ShenandoahAllocationTrace) {
1207 assert(alloc_tracker() != NULL, "Must be");
1208 alloc_tracker()->print_on(&ls);
1209 } else {
1210 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1211 }
1212 }
1213 }
1214
1215 void ShenandoahHeap::verify(VerifyOption vo) {
1216 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1217 if (ShenandoahVerify) {
1218 verifier()->verify_generic(vo);
1219 } else {
1220 // TODO: Consider allocating verification bitmaps on demand,
1221 // and turn this on unconditionally.
1222 }
1223 }
1224 }
1225 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1226 return _free_set->capacity();
1227 }
1228
1229 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1230 private:
1231 MarkBitMap* _bitmap;
1232 Stack<oop,mtGC>* _oop_stack;
1233 ShenandoahHeap* const _heap;
1234 ShenandoahMarkingContext* const _marking_context;
1235
1236 template <class T>
1237 void do_oop_work(T* p) {
1238 T o = RawAccess<>::oop_load(p);
1239 if (!CompressedOops::is_null(o)) {
1240 oop obj = CompressedOops::decode_not_null(o);
1241 if (_heap->is_concurrent_root_in_progress() && !_marking_context->is_marked(obj)) {
1242 // There may be dead oops in weak roots in concurrent root phase, do not touch them.
1243 return;
1244 }
1245 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1246
1247 assert(oopDesc::is_oop(obj), "must be a valid oop");
1248 if (!_bitmap->is_marked(obj)) {
1249 _bitmap->mark(obj);
1250 _oop_stack->push(obj);
1251 }
1252 }
1253 }
1254 public:
1255 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1256 _bitmap(bitmap), _oop_stack(oop_stack), _heap(ShenandoahHeap::heap()),
1257 _marking_context(_heap->marking_context()) {}
1258 void do_oop(oop* p) { do_oop_work(p); }
1259 void do_oop(narrowOop* p) { do_oop_work(p); }
1260 };
1261
1262 /*
1263 * This is public API, used in preparation of object_iterate().
1264 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1265 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1266 * control, we call SH::make_tlabs_parsable().
1267 */
1268 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1269 // No-op.
1270 }
1271
1272 /*
1273 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1274 *
1275 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1276 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1277 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1278 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1279 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1280 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1281 * wiped the bitmap in preparation for next marking).
1282 *
1283 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1284 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1285 * is allowed to report dead objects, but is not required to do so.
1286 */
1287 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1288 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1289 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1290 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1291 return;
1292 }
1293
1294 // Reset bitmap
1295 _aux_bit_map.clear();
1296
1297 Stack<oop,mtGC> oop_stack;
1298
1299 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects.
1300 ShenandoahHeapIterationRootScanner rp;
1301 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1302
1303 rp.roots_do(&oops);
1304
1305 // Work through the oop stack to traverse heap.
1306 while (! oop_stack.is_empty()) {
1307 oop obj = oop_stack.pop();
1308 assert(oopDesc::is_oop(obj), "must be a valid oop");
1309 cl->do_object(obj);
1310 obj->oop_iterate(&oops);
1311 }
1312
1313 assert(oop_stack.is_empty(), "should be empty");
1314
1315 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1316 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1317 }
1318 }
1319
1320 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1321 void ShenandoahHeap::keep_alive(oop obj) {
1322 if (is_concurrent_mark_in_progress()) {
1323 ShenandoahBarrierSet::barrier_set()->enqueue(obj);
1324 }
1325 }
1326
1327 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1328 for (size_t i = 0; i < num_regions(); i++) {
1329 ShenandoahHeapRegion* current = get_region(i);
1330 blk->heap_region_do(current);
1331 }
1332 }
1333
1334 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1335 private:
1336 ShenandoahHeap* const _heap;
1337 ShenandoahHeapRegionClosure* const _blk;
1338
1339 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1340 volatile size_t _index;
1341 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1342
1343 public:
1344 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1345 AbstractGangTask("Parallel Region Task"),
1346 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1347
1348 void work(uint worker_id) {
1349 size_t stride = ShenandoahParallelRegionStride;
1350
1351 size_t max = _heap->num_regions();
1352 while (_index < max) {
1353 size_t cur = Atomic::fetch_and_add(&_index, stride);
1354 size_t start = cur;
1355 size_t end = MIN2(cur + stride, max);
1356 if (start >= max) break;
1357
1358 for (size_t i = cur; i < end; i++) {
1359 ShenandoahHeapRegion* current = _heap->get_region(i);
1360 _blk->heap_region_do(current);
1361 }
1362 }
1363 }
1364 };
1365
1366 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1367 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1368 if (num_regions() > ShenandoahParallelRegionStride) {
1369 ShenandoahParallelHeapRegionTask task(blk);
1370 workers()->run_task(&task);
1371 } else {
1372 heap_region_iterate(blk);
1373 }
1374 }
1375
1376 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1377 private:
1378 ShenandoahMarkingContext* const _ctx;
1379 public:
1380 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1381
1382 void heap_region_do(ShenandoahHeapRegion* r) {
1383 if (r->is_active()) {
1384 r->clear_live_data();
1385 _ctx->capture_top_at_mark_start(r);
1386 } else {
1387 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1388 assert(_ctx->top_at_mark_start(r) == r->top(),
1389 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1390 }
1391 }
1392
1393 bool is_thread_safe() { return true; }
1394 };
1395
1396 void ShenandoahHeap::op_init_mark() {
1397 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1398 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1399
1400 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1401 assert(!marking_context()->is_complete(), "should not be complete");
1402
1403 if (ShenandoahVerify) {
1404 verifier()->verify_before_concmark();
1405 }
1406
1407 if (VerifyBeforeGC) {
1408 Universe::verify();
1409 }
1410
1411 set_concurrent_mark_in_progress(true);
1412 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1413 {
1414 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1415 make_parsable(true);
1416 }
1417
1418 {
1419 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1420 ShenandoahClearLivenessClosure clc;
1421 parallel_heap_region_iterate(&clc);
1422 }
1423
1424 // Make above changes visible to worker threads
1425 OrderAccess::fence();
1426
1427 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1428
1429 if (UseTLAB) {
1430 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1431 resize_tlabs();
1432 }
1433
1434 if (ShenandoahPacing) {
1435 pacer()->setup_for_mark();
1436 }
1437 }
1438
1439 void ShenandoahHeap::op_mark() {
1440 concurrent_mark()->mark_from_roots();
1441 }
1442
1443 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1444 private:
1445 ShenandoahMarkingContext* const _ctx;
1446 public:
1447 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1448
1449 void heap_region_do(ShenandoahHeapRegion* r) {
1450 if (r->is_active()) {
1451 HeapWord *tams = _ctx->top_at_mark_start(r);
1452 HeapWord *top = r->top();
1453 if (top > tams) {
1454 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1455 }
1456 } else {
1457 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1458 assert(_ctx->top_at_mark_start(r) == r->top(),
1459 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1460 }
1461 }
1462
1463 bool is_thread_safe() { return true; }
1464 };
1465
1466 void ShenandoahHeap::op_final_mark() {
1467 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1468
1469 // It is critical that we
1470 // evacuate roots right after finishing marking, so that we don't
1471 // get unmarked objects in the roots.
1472
1473 if (!cancelled_gc()) {
1474 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1475
1476 // Marking is completed, deactivate SATB barrier
1477 set_concurrent_mark_in_progress(false);
1478 mark_complete_marking_context();
1479
1480 parallel_cleaning(false /* full gc*/);
1481
1482 if (has_forwarded_objects()) {
1483 // Degen may be caused by failed evacuation of roots
1484 if (is_degenerated_gc_in_progress()) {
1485 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
1486 } else {
1487 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::update_roots);
1488 }
1489 set_has_forwarded_objects(false);
1490 }
1491
1492 if (ShenandoahVerify) {
1493 verifier()->verify_roots_no_forwarded();
1494 }
1495 // All allocations past TAMS are implicitly live, adjust the region data.
1496 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1497 {
1498 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1499 ShenandoahCompleteLivenessClosure cl;
1500 parallel_heap_region_iterate(&cl);
1501 }
1502
1503 // Force the threads to reacquire their TLABs outside the collection set.
1504 {
1505 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs);
1506 make_parsable(true);
1507 }
1508
1509 // We are about to select the collection set, make sure it knows about
1510 // current pinning status. Also, this allows trashing more regions that
1511 // now have their pinning status dropped.
1512 {
1513 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned);
1514 sync_pinned_region_status();
1515 }
1516
1517 // Trash the collection set left over from previous cycle, if any.
1518 {
1519 ShenandoahGCPhase phase(ShenandoahPhaseTimings::trash_cset);
1520 trash_cset_regions();
1521 }
1522
1523 {
1524 ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac);
1525
1526 ShenandoahHeapLocker locker(lock());
1527 _collection_set->clear();
1528 _free_set->clear();
1529
1530 heuristics()->choose_collection_set(_collection_set);
1531
1532 _free_set->rebuild();
1533 }
1534
1535 if (!is_degenerated_gc_in_progress()) {
1536 prepare_concurrent_roots();
1537 prepare_concurrent_unloading();
1538 }
1539
1540 // If collection set has candidates, start evacuation.
1541 // Otherwise, bypass the rest of the cycle.
1542 if (!collection_set()->is_empty()) {
1543 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1544
1545 if (ShenandoahVerify) {
1546 verifier()->verify_before_evacuation();
1547 }
1548
1549 set_evacuation_in_progress(true);
1550 // From here on, we need to update references.
1551 set_has_forwarded_objects(true);
1552
1553 if (!is_degenerated_gc_in_progress()) {
1554 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1555 ShenandoahCodeRoots::arm_nmethods();
1556 }
1557 evacuate_and_update_roots();
1558 }
1559
1560 if (ShenandoahPacing) {
1561 pacer()->setup_for_evac();
1562 }
1563
1564 if (ShenandoahVerify) {
1565 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None;
1566 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1567 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots);
1568 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots);
1569 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::StringDedupRoots);
1570 }
1571
1572 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1573 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CodeRoots);
1574 }
1575 verifier()->verify_roots_no_forwarded_except(types);
1576 verifier()->verify_during_evacuation();
1577 }
1578 } else {
1579 if (ShenandoahVerify) {
1580 verifier()->verify_after_concmark();
1581 }
1582
1583 if (VerifyAfterGC) {
1584 Universe::verify();
1585 }
1586 }
1587
1588 } else {
1589 // If this cycle was updating references, we need to keep the has_forwarded_objects
1590 // flag on, for subsequent phases to deal with it.
1591 concurrent_mark()->cancel();
1592 set_concurrent_mark_in_progress(false);
1593
1594 if (process_references()) {
1595 // Abandon reference processing right away: pre-cleaning must have failed.
1596 ReferenceProcessor *rp = ref_processor();
1597 rp->disable_discovery();
1598 rp->abandon_partial_discovery();
1599 rp->verify_no_references_recorded();
1600 }
1601 }
1602 }
1603
1604 void ShenandoahHeap::op_final_evac() {
1605 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1606
1607 set_evacuation_in_progress(false);
1608
1609 {
1610 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_retire_gclabs);
1611 retire_and_reset_gclabs();
1612 }
1613
1614 if (ShenandoahVerify) {
1615 verifier()->verify_after_evacuation();
1616 }
1617
1618 if (VerifyAfterGC) {
1619 Universe::verify();
1620 }
1621 }
1622
1623 void ShenandoahHeap::op_conc_evac() {
1624 ShenandoahEvacuationTask task(this, _collection_set, true);
1625 workers()->run_task(&task);
1626 }
1627
1628 void ShenandoahHeap::op_stw_evac() {
1629 ShenandoahEvacuationTask task(this, _collection_set, false);
1630 workers()->run_task(&task);
1631 }
1632
1633 void ShenandoahHeap::op_updaterefs() {
1634 update_heap_references(true);
1635 }
1636
1637 void ShenandoahHeap::op_cleanup() {
1638 free_set()->recycle_trash();
1639 }
1640
1641 class ShenandoahConcurrentRootsEvacUpdateTask : public AbstractGangTask {
1642 private:
1643 ShenandoahVMRoots<true /*concurrent*/> _vm_roots;
1644 ShenandoahWeakRoots<true /*concurrent*/> _weak_roots;
1645 ShenandoahClassLoaderDataRoots<true /*concurrent*/, false /*single threaded*/> _cld_roots;
1646 ShenandoahConcurrentStringDedupRoots _dedup_roots;
1647 bool _include_weak_roots;
1648
1649 public:
1650 ShenandoahConcurrentRootsEvacUpdateTask(bool include_weak_roots) :
1651 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task"),
1652 _include_weak_roots(include_weak_roots) {
1653 }
1654
1655 void work(uint worker_id) {
1656 ShenandoahEvacOOMScope oom;
1657 {
1658 // vm_roots and weak_roots are OopStorage backed roots, concurrent iteration
1659 // may race against OopStorage::release() calls.
1660 ShenandoahEvacUpdateOopStorageRootsClosure cl;
1661 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1662
1663 if (_include_weak_roots) {
1664 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1665 }
1666 }
1667
1668 {
1669 ShenandoahEvacuateUpdateRootsClosure<> cl;
1670 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong);
1671 _cld_roots.cld_do(&clds);
1672 }
1673
1674 {
1675 ShenandoahForwardedIsAliveClosure is_alive;
1676 ShenandoahEvacuateUpdateRootsClosure<MO_RELEASE> keep_alive;
1677 _dedup_roots.oops_do(&is_alive, &keep_alive, worker_id);
1678 }
1679 }
1680 };
1681
1682 class ShenandoahEvacUpdateCleanupOopStorageRootsClosure : public BasicOopIterateClosure {
1683 private:
1684 ShenandoahHeap* const _heap;
1685 ShenandoahMarkingContext* const _mark_context;
1686 bool _evac_in_progress;
1687 Thread* const _thread;
1688 size_t _dead_counter;
1689
1690 public:
1691 ShenandoahEvacUpdateCleanupOopStorageRootsClosure();
1692 void do_oop(oop* p);
1693 void do_oop(narrowOop* p);
1694
1695 size_t dead_counter() const;
1696 void reset_dead_counter();
1697 };
1698
1699 ShenandoahEvacUpdateCleanupOopStorageRootsClosure::ShenandoahEvacUpdateCleanupOopStorageRootsClosure() :
1700 _heap(ShenandoahHeap::heap()),
1701 _mark_context(ShenandoahHeap::heap()->marking_context()),
1702 _evac_in_progress(ShenandoahHeap::heap()->is_evacuation_in_progress()),
1703 _thread(Thread::current()),
1704 _dead_counter(0) {
1705 }
1706
1707 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(oop* p) {
1708 const oop obj = RawAccess<>::oop_load(p);
1709 if (!CompressedOops::is_null(obj)) {
1710 if (!_mark_context->is_marked(obj)) {
1711 shenandoah_assert_correct(p, obj);
1712 oop old = Atomic::cmpxchg(p, obj, oop(NULL));
1713 if (obj == old) {
1714 _dead_counter ++;
1715 }
1716 } else if (_evac_in_progress && _heap->in_collection_set(obj)) {
1717 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1718 if (resolved == obj) {
1719 resolved = _heap->evacuate_object(obj, _thread);
1720 }
1721 Atomic::cmpxchg(p, obj, resolved);
1722 assert(_heap->cancelled_gc() ||
1723 _mark_context->is_marked(resolved) && !_heap->in_collection_set(resolved),
1724 "Sanity");
1725 }
1726 }
1727 }
1728
1729 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(narrowOop* p) {
1730 ShouldNotReachHere();
1731 }
1732
1733 size_t ShenandoahEvacUpdateCleanupOopStorageRootsClosure::dead_counter() const {
1734 return _dead_counter;
1735 }
1736
1737 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::reset_dead_counter() {
1738 _dead_counter = 0;
1739 }
1740
1741 // This task not only evacuates/updates marked weak roots, but also "NULL"
1742 // dead weak roots.
1743 class ShenandoahConcurrentWeakRootsEvacUpdateTask : public AbstractGangTask {
1744 private:
1745 ShenandoahWeakRoot<true /*concurrent*/> _jni_roots;
1746 ShenandoahWeakRoot<true /*concurrent*/> _string_table_roots;
1747 ShenandoahWeakRoot<true /*concurrent*/> _resolved_method_table_roots;
1748 ShenandoahWeakRoot<true /*concurrent*/> _vm_roots;
1749
1750 public:
1751 ShenandoahConcurrentWeakRootsEvacUpdateTask() :
1752 AbstractGangTask("Shenandoah Concurrent Weak Root Task"),
1753 _jni_roots(OopStorageSet::jni_weak(), ShenandoahPhaseTimings::JNIWeakRoots),
1754 _string_table_roots(OopStorageSet::string_table_weak(), ShenandoahPhaseTimings::StringTableRoots),
1755 _resolved_method_table_roots(OopStorageSet::resolved_method_table_weak(), ShenandoahPhaseTimings::ResolvedMethodTableRoots),
1756 _vm_roots(OopStorageSet::vm_weak(), ShenandoahPhaseTimings::VMWeakRoots) {
1757 StringTable::reset_dead_counter();
1758 ResolvedMethodTable::reset_dead_counter();
1759 }
1760
1761 ~ShenandoahConcurrentWeakRootsEvacUpdateTask() {
1762 StringTable::finish_dead_counter();
1763 ResolvedMethodTable::finish_dead_counter();
1764 }
1765
1766 void work(uint worker_id) {
1767 ShenandoahEvacOOMScope oom;
1768 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration
1769 // may race against OopStorage::release() calls.
1770 ShenandoahEvacUpdateCleanupOopStorageRootsClosure cl;
1771 _jni_roots.oops_do(&cl, worker_id);
1772 _vm_roots.oops_do(&cl, worker_id);
1773
1774 cl.reset_dead_counter();
1775 _string_table_roots.oops_do(&cl, worker_id);
1776 StringTable::inc_dead_counter(cl.dead_counter());
1777
1778 cl.reset_dead_counter();
1779 _resolved_method_table_roots.oops_do(&cl, worker_id);
1780 ResolvedMethodTable::inc_dead_counter(cl.dead_counter());
1781 }
1782 };
1783
1784 void ShenandoahHeap::op_roots() {
1785 if (is_concurrent_root_in_progress()) {
1786 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1787 // Concurrent weak root processing
1788 ShenandoahConcurrentWeakRootsEvacUpdateTask task;
1789 workers()->run_task(&task);
1790
1791 _unloader.unload();
1792 }
1793
1794 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1795 ShenandoahConcurrentRootsEvacUpdateTask task(!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1796 workers()->run_task(&task);
1797 }
1798 }
1799
1800 set_concurrent_root_in_progress(false);
1801 }
1802
1803 void ShenandoahHeap::op_reset() {
1804 reset_mark_bitmap();
1805 }
1806
1807 void ShenandoahHeap::op_preclean() {
1808 concurrent_mark()->preclean_weak_refs();
1809 }
1810
1811 void ShenandoahHeap::op_init_traversal() {
1812 traversal_gc()->init_traversal_collection();
1813 }
1814
1815 void ShenandoahHeap::op_traversal() {
1816 traversal_gc()->concurrent_traversal_collection();
1817 }
1818
1819 void ShenandoahHeap::op_final_traversal() {
1820 traversal_gc()->final_traversal_collection();
1821 }
1822
1823 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1824 ShenandoahMetricsSnapshot metrics;
1825 metrics.snap_before();
1826
1827 full_gc()->do_it(cause);
1828 if (UseTLAB) {
1829 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1830 resize_all_tlabs();
1831 }
1832
1833 metrics.snap_after();
1834
1835 if (metrics.is_good_progress()) {
1836 _progress_last_gc.set();
1837 } else {
1838 // Nothing to do. Tell the allocation path that we have failed to make
1839 // progress, and it can finally fail.
1840 _progress_last_gc.unset();
1841 }
1842 }
1843
1844 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1845 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1846 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1847 // some phase, we have to upgrade the Degenerate GC to Full GC.
1848
1849 clear_cancelled_gc();
1850
1851 ShenandoahMetricsSnapshot metrics;
1852 metrics.snap_before();
1853
1854 switch (point) {
1855 case _degenerated_traversal:
1856 {
1857 // Drop the collection set. Note: this leaves some already forwarded objects
1858 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1859 // workarounds in ShenandoahTraversalHeuristics.
1860
1861 ShenandoahHeapLocker locker(lock());
1862 collection_set()->clear_current_index();
1863 for (size_t i = 0; i < collection_set()->count(); i++) {
1864 ShenandoahHeapRegion* r = collection_set()->next();
1865 r->make_regular_bypass();
1866 }
1867 collection_set()->clear();
1868 }
1869 op_final_traversal();
1870 op_cleanup();
1871 return;
1872
1873 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1874 // but enters it at different points, depending on which concurrent phase had
1875 // degenerated.
1876
1877 case _degenerated_outside_cycle:
1878 // We have degenerated from outside the cycle, which means something is bad with
1879 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1880 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1881 // we can do the most aggressive degen cycle, which includes processing references and
1882 // class unloading, unless those features are explicitly disabled.
1883 //
1884 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1885 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1886 set_process_references(heuristics()->can_process_references());
1887 set_unload_classes(heuristics()->can_unload_classes());
1888
1889 if (is_traversal_mode()) {
1890 // Not possible to degenerate from here, upgrade to Full GC right away.
1891 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1892 op_degenerated_fail();
1893 return;
1894 }
1895
1896 op_reset();
1897
1898 op_init_mark();
1899 if (cancelled_gc()) {
1900 op_degenerated_fail();
1901 return;
1902 }
1903
1904 case _degenerated_mark:
1905 op_final_mark();
1906 if (cancelled_gc()) {
1907 op_degenerated_fail();
1908 return;
1909 }
1910
1911 op_cleanup();
1912
1913 case _degenerated_evac:
1914 // If heuristics thinks we should do the cycle, this flag would be set,
1915 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1916 if (is_evacuation_in_progress()) {
1917
1918 // Degeneration under oom-evac protocol might have left some objects in
1919 // collection set un-evacuated. Restart evacuation from the beginning to
1920 // capture all objects. For all the objects that are already evacuated,
1921 // it would be a simple check, which is supposed to be fast. This is also
1922 // safe to do even without degeneration, as CSet iterator is at beginning
1923 // in preparation for evacuation anyway.
1924 //
1925 // Before doing that, we need to make sure we never had any cset-pinned
1926 // regions. This may happen if allocation failure happened when evacuating
1927 // the about-to-be-pinned object, oom-evac protocol left the object in
1928 // the collection set, and then the pin reached the cset region. If we continue
1929 // the cycle here, we would trash the cset and alive objects in it. To avoid
1930 // it, we fail degeneration right away and slide into Full GC to recover.
1931
1932 {
1933 sync_pinned_region_status();
1934 collection_set()->clear_current_index();
1935
1936 ShenandoahHeapRegion* r;
1937 while ((r = collection_set()->next()) != NULL) {
1938 if (r->is_pinned()) {
1939 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1940 op_degenerated_fail();
1941 return;
1942 }
1943 }
1944
1945 collection_set()->clear_current_index();
1946 }
1947
1948 op_stw_evac();
1949 if (cancelled_gc()) {
1950 op_degenerated_fail();
1951 return;
1952 }
1953 }
1954
1955 // If heuristics thinks we should do the cycle, this flag would be set,
1956 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1957 if (has_forwarded_objects()) {
1958 op_init_updaterefs();
1959 if (cancelled_gc()) {
1960 op_degenerated_fail();
1961 return;
1962 }
1963 }
1964
1965 case _degenerated_updaterefs:
1966 if (has_forwarded_objects()) {
1967 op_final_updaterefs();
1968 if (cancelled_gc()) {
1969 op_degenerated_fail();
1970 return;
1971 }
1972 }
1973
1974 op_cleanup();
1975 break;
1976
1977 default:
1978 ShouldNotReachHere();
1979 }
1980
1981 if (ShenandoahVerify) {
1982 verifier()->verify_after_degenerated();
1983 }
1984
1985 if (VerifyAfterGC) {
1986 Universe::verify();
1987 }
1988
1989 metrics.snap_after();
1990
1991 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1992 // because that probably means the heap is overloaded and/or fragmented.
1993 if (!metrics.is_good_progress()) {
1994 _progress_last_gc.unset();
1995 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1996 op_degenerated_futile();
1997 } else {
1998 _progress_last_gc.set();
1999 }
2000 }
2001
2002 void ShenandoahHeap::op_degenerated_fail() {
2003 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
2004 shenandoah_policy()->record_degenerated_upgrade_to_full();
2005 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
2006 }
2007
2008 void ShenandoahHeap::op_degenerated_futile() {
2009 shenandoah_policy()->record_degenerated_upgrade_to_full();
2010 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
2011 }
2012
2013 void ShenandoahHeap::force_satb_flush_all_threads() {
2014 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
2015 // No need to flush SATBs
2016 return;
2017 }
2018
2019 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2020 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
2021 }
2022 // The threads are not "acquiring" their thread-local data, but it does not
2023 // hurt to "release" the updates here anyway.
2024 OrderAccess::fence();
2025 }
2026
2027 void ShenandoahHeap::set_gc_state_all_threads(char state) {
2028 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2029 ShenandoahThreadLocalData::set_gc_state(t, state);
2030 }
2031 }
2032
2033 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
2034 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
2035 _gc_state.set_cond(mask, value);
2036 set_gc_state_all_threads(_gc_state.raw_value());
2037 }
2038
2039 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
2040 if (has_forwarded_objects()) {
2041 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
2042 } else {
2043 set_gc_state_mask(MARKING, in_progress);
2044 }
2045 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2046 }
2047
2048 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
2049 set_gc_state_mask(TRAVERSAL, in_progress);
2050 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2051 }
2052
2053 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2054 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
2055 set_gc_state_mask(EVACUATION, in_progress);
2056 }
2057
2058 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) {
2059 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?");
2060 if (in_progress) {
2061 _concurrent_root_in_progress.set();
2062 } else {
2063 _concurrent_root_in_progress.unset();
2064 }
2065 }
2066
2067 void ShenandoahHeap::ref_processing_init() {
2068 assert(_max_workers > 0, "Sanity");
2069
2070 _ref_processor =
2071 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
2072 ParallelRefProcEnabled, // MT processing
2073 _max_workers, // Degree of MT processing
2074 true, // MT discovery
2075 _max_workers, // Degree of MT discovery
2076 false, // Reference discovery is not atomic
2077 NULL, // No closure, should be installed before use
2078 true); // Scale worker threads
2079
2080 shenandoah_assert_rp_isalive_not_installed();
2081 }
2082
2083 GCTracer* ShenandoahHeap::tracer() {
2084 return shenandoah_policy()->tracer();
2085 }
2086
2087 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2088 return _free_set->used();
2089 }
2090
2091 bool ShenandoahHeap::try_cancel_gc() {
2092 while (true) {
2093 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
2094 if (prev == CANCELLABLE) return true;
2095 else if (prev == CANCELLED) return false;
2096 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
2097 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
2098 if (Thread::current()->is_Java_thread()) {
2099 // We need to provide a safepoint here, otherwise we might
2100 // spin forever if a SP is pending.
2101 ThreadBlockInVM sp(JavaThread::current());
2102 SpinPause();
2103 }
2104 }
2105 }
2106
2107 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
2108 if (try_cancel_gc()) {
2109 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
2110 log_info(gc)("%s", msg.buffer());
2111 Events::log(Thread::current(), "%s", msg.buffer());
2112 }
2113 }
2114
2115 uint ShenandoahHeap::max_workers() {
2116 return _max_workers;
2117 }
2118
2119 void ShenandoahHeap::stop() {
2120 // The shutdown sequence should be able to terminate when GC is running.
2121
2122 // Step 0. Notify policy to disable event recording.
2123 _shenandoah_policy->record_shutdown();
2124
2125 // Step 1. Notify control thread that we are in shutdown.
2126 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2127 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2128 control_thread()->prepare_for_graceful_shutdown();
2129
2130 // Step 2. Notify GC workers that we are cancelling GC.
2131 cancel_gc(GCCause::_shenandoah_stop_vm);
2132
2133 // Step 3. Wait until GC worker exits normally.
2134 control_thread()->stop();
2135
2136 // Step 4. Stop String Dedup thread if it is active
2137 if (ShenandoahStringDedup::is_enabled()) {
2138 ShenandoahStringDedup::stop();
2139 }
2140 }
2141
2142 void ShenandoahHeap::stw_unload_classes(bool full_gc) {
2143 if (!unload_classes()) return;
2144 bool purged_class;
2145
2146 // Unload classes and purge SystemDictionary.
2147 {
2148 ShenandoahGCPhase phase(full_gc ?
2149 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2150 ShenandoahPhaseTimings::purge_class_unload);
2151 purged_class = SystemDictionary::do_unloading(gc_timer());
2152 }
2153
2154 {
2155 ShenandoahGCPhase phase(full_gc ?
2156 ShenandoahPhaseTimings::full_gc_purge_par :
2157 ShenandoahPhaseTimings::purge_par);
2158 ShenandoahIsAliveSelector is_alive;
2159 uint num_workers = _workers->active_workers();
2160 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class);
2161 _workers->run_task(&unlink_task);
2162 }
2163
2164 {
2165 ShenandoahGCPhase phase(full_gc ?
2166 ShenandoahPhaseTimings::full_gc_purge_cldg :
2167 ShenandoahPhaseTimings::purge_cldg);
2168 ClassLoaderDataGraph::purge();
2169 }
2170 // Resize and verify metaspace
2171 MetaspaceGC::compute_new_size();
2172 MetaspaceUtils::verify_metrics();
2173 }
2174
2175 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs),
2176 // so they should not have forwarded oops.
2177 // However, we do need to "null" dead oops in the roots, if can not be done
2178 // in concurrent cycles.
2179 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) {
2180 ShenandoahGCPhase root_phase(full_gc ?
2181 ShenandoahPhaseTimings::full_gc_purge :
2182 ShenandoahPhaseTimings::purge);
2183 uint num_workers = _workers->active_workers();
2184 ShenandoahPhaseTimings::Phase timing_phase = full_gc ?
2185 ShenandoahPhaseTimings::full_gc_purge_par :
2186 ShenandoahPhaseTimings::purge_par;
2187 // Cleanup weak roots
2188 ShenandoahGCPhase phase(timing_phase);
2189 phase_timings()->record_workers_start(timing_phase);
2190 if (has_forwarded_objects()) {
2191 if (is_traversal_mode()) {
2192 ShenandoahForwardedIsAliveClosure is_alive;
2193 ShenandoahTraversalUpdateRefsClosure keep_alive;
2194 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahTraversalUpdateRefsClosure>
2195 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2196 _workers->run_task(&cleaning_task);
2197 } else {
2198 ShenandoahForwardedIsAliveClosure is_alive;
2199 ShenandoahUpdateRefsClosure keep_alive;
2200 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure>
2201 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2202 _workers->run_task(&cleaning_task);
2203 }
2204 } else {
2205 ShenandoahIsAliveClosure is_alive;
2206 #ifdef ASSERT
2207 ShenandoahAssertNotForwardedClosure verify_cl;
2208 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure>
2209 cleaning_task(&is_alive, &verify_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2210 #else
2211 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure>
2212 cleaning_task(&is_alive, &do_nothing_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2213 #endif
2214 _workers->run_task(&cleaning_task);
2215 }
2216 phase_timings()->record_workers_end(timing_phase);
2217 }
2218
2219 void ShenandoahHeap::parallel_cleaning(bool full_gc) {
2220 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2221 stw_process_weak_roots(full_gc);
2222 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2223 stw_unload_classes(full_gc);
2224 }
2225 }
2226
2227 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2228 if (is_traversal_mode()) {
2229 set_gc_state_mask(HAS_FORWARDED | UPDATEREFS, cond);
2230 } else {
2231 set_gc_state_mask(HAS_FORWARDED, cond);
2232 }
2233
2234 }
2235
2236 void ShenandoahHeap::set_process_references(bool pr) {
2237 _process_references.set_cond(pr);
2238 }
2239
2240 void ShenandoahHeap::set_unload_classes(bool uc) {
2241 _unload_classes.set_cond(uc);
2242 }
2243
2244 bool ShenandoahHeap::process_references() const {
2245 return _process_references.is_set();
2246 }
2247
2248 bool ShenandoahHeap::unload_classes() const {
2249 return _unload_classes.is_set();
2250 }
2251
2252 address ShenandoahHeap::in_cset_fast_test_addr() {
2253 ShenandoahHeap* heap = ShenandoahHeap::heap();
2254 assert(heap->collection_set() != NULL, "Sanity");
2255 return (address) heap->collection_set()->biased_map_address();
2256 }
2257
2258 address ShenandoahHeap::cancelled_gc_addr() {
2259 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2260 }
2261
2262 address ShenandoahHeap::gc_state_addr() {
2263 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2264 }
2265
2266 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2267 return Atomic::load_acquire(&_bytes_allocated_since_gc_start);
2268 }
2269
2270 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2271 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2272 }
2273
2274 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2275 _degenerated_gc_in_progress.set_cond(in_progress);
2276 }
2277
2278 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2279 _full_gc_in_progress.set_cond(in_progress);
2280 }
2281
2282 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2283 assert (is_full_gc_in_progress(), "should be");
2284 _full_gc_move_in_progress.set_cond(in_progress);
2285 }
2286
2287 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2288 set_gc_state_mask(UPDATEREFS, in_progress);
2289 }
2290
2291 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2292 ShenandoahCodeRoots::register_nmethod(nm);
2293 }
2294
2295 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2296 ShenandoahCodeRoots::unregister_nmethod(nm);
2297 }
2298
2299 void ShenandoahHeap::flush_nmethod(nmethod* nm) {
2300 ShenandoahCodeRoots::flush_nmethod(nm);
2301 }
2302
2303 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2304 heap_region_containing(o)->record_pin();
2305 return o;
2306 }
2307
2308 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2309 heap_region_containing(o)->record_unpin();
2310 }
2311
2312 void ShenandoahHeap::sync_pinned_region_status() {
2313 ShenandoahHeapLocker locker(lock());
2314
2315 for (size_t i = 0; i < num_regions(); i++) {
2316 ShenandoahHeapRegion *r = get_region(i);
2317 if (r->is_active()) {
2318 if (r->is_pinned()) {
2319 if (r->pin_count() == 0) {
2320 r->make_unpinned();
2321 }
2322 } else {
2323 if (r->pin_count() > 0) {
2324 r->make_pinned();
2325 }
2326 }
2327 }
2328 }
2329
2330 assert_pinned_region_status();
2331 }
2332
2333 #ifdef ASSERT
2334 void ShenandoahHeap::assert_pinned_region_status() {
2335 for (size_t i = 0; i < num_regions(); i++) {
2336 ShenandoahHeapRegion* r = get_region(i);
2337 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0),
2338 "Region " SIZE_FORMAT " pinning status is inconsistent", i);
2339 }
2340 }
2341 #endif
2342
2343 GCTimer* ShenandoahHeap::gc_timer() const {
2344 return _gc_timer;
2345 }
2346
2347 void ShenandoahHeap::prepare_concurrent_roots() {
2348 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2349 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
2350 set_concurrent_root_in_progress(true);
2351 }
2352 }
2353
2354 void ShenandoahHeap::prepare_concurrent_unloading() {
2355 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2356 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2357 _unloader.prepare();
2358 }
2359 }
2360
2361 void ShenandoahHeap::finish_concurrent_unloading() {
2362 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2363 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2364 _unloader.finish();
2365 }
2366 }
2367
2368 #ifdef ASSERT
2369 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2370 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2371
2372 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2373 if (UseDynamicNumberOfGCThreads ||
2374 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2375 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2376 } else {
2377 // Use ParallelGCThreads inside safepoints
2378 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2379 }
2380 } else {
2381 if (UseDynamicNumberOfGCThreads ||
2382 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2383 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2384 } else {
2385 // Use ConcGCThreads outside safepoints
2386 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2387 }
2388 }
2389 }
2390 #endif
2391
2392 ShenandoahVerifier* ShenandoahHeap::verifier() {
2393 guarantee(ShenandoahVerify, "Should be enabled");
2394 assert (_verifier != NULL, "sanity");
2395 return _verifier;
2396 }
2397
2398 template<class T>
2399 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2400 private:
2401 T cl;
2402 ShenandoahHeap* _heap;
2403 ShenandoahRegionIterator* _regions;
2404 bool _concurrent;
2405 public:
2406 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2407 AbstractGangTask("Concurrent Update References Task"),
2408 cl(T()),
2409 _heap(ShenandoahHeap::heap()),
2410 _regions(regions),
2411 _concurrent(concurrent) {
2412 }
2413
2414 void work(uint worker_id) {
2415 if (_concurrent) {
2416 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2417 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2418 do_work();
2419 } else {
2420 ShenandoahParallelWorkerSession worker_session(worker_id);
2421 do_work();
2422 }
2423 }
2424
2425 private:
2426 void do_work() {
2427 ShenandoahHeapRegion* r = _regions->next();
2428 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2429 while (r != NULL) {
2430 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2431 assert (top_at_start_ur >= r->bottom(), "sanity");
2432 if (r->is_active() && !r->is_cset()) {
2433 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2434 }
2435 if (ShenandoahPacing) {
2436 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2437 }
2438 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2439 return;
2440 }
2441 r = _regions->next();
2442 }
2443 }
2444 };
2445
2446 void ShenandoahHeap::update_heap_references(bool concurrent) {
2447 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2448 workers()->run_task(&task);
2449 }
2450
2451 void ShenandoahHeap::op_init_updaterefs() {
2452 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2453
2454 set_evacuation_in_progress(false);
2455
2456 {
2457 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs);
2458 retire_and_reset_gclabs();
2459 }
2460
2461 if (ShenandoahVerify) {
2462 if (!is_degenerated_gc_in_progress()) {
2463 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2464 }
2465 verifier()->verify_before_updaterefs();
2466 }
2467
2468 set_update_refs_in_progress(true);
2469
2470 {
2471 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare);
2472
2473 make_parsable(true);
2474 for (uint i = 0; i < num_regions(); i++) {
2475 ShenandoahHeapRegion* r = get_region(i);
2476 r->set_concurrent_iteration_safe_limit(r->top());
2477 }
2478
2479 // Reset iterator.
2480 _update_refs_iterator.reset();
2481 }
2482
2483 if (ShenandoahPacing) {
2484 pacer()->setup_for_updaterefs();
2485 }
2486 }
2487
2488 void ShenandoahHeap::op_final_updaterefs() {
2489 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2490
2491 finish_concurrent_unloading();
2492
2493 // Check if there is left-over work, and finish it
2494 if (_update_refs_iterator.has_next()) {
2495 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work);
2496
2497 // Finish updating references where we left off.
2498 clear_cancelled_gc();
2499 update_heap_references(false);
2500 }
2501
2502 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2503 // everything. On degenerated paths, cancelled gc would not be set anyway.
2504 if (cancelled_gc()) {
2505 clear_cancelled_gc();
2506 }
2507 assert(!cancelled_gc(), "Should have been done right before");
2508
2509 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) {
2510 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2511 }
2512
2513 if (is_degenerated_gc_in_progress()) {
2514 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
2515 } else {
2516 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2517 }
2518
2519 // Has to be done before cset is clear
2520 if (ShenandoahVerify) {
2521 verifier()->verify_roots_in_to_space();
2522 }
2523
2524 // Drop unnecessary "pinned" state from regions that does not have CP marks
2525 // anymore, as this would allow trashing them below.
2526 {
2527 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned);
2528 sync_pinned_region_status();
2529 }
2530
2531 {
2532 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset);
2533 trash_cset_regions();
2534 }
2535
2536 set_has_forwarded_objects(false);
2537 set_update_refs_in_progress(false);
2538
2539 if (ShenandoahVerify) {
2540 verifier()->verify_after_updaterefs();
2541 }
2542
2543 if (VerifyAfterGC) {
2544 Universe::verify();
2545 }
2546
2547 {
2548 ShenandoahHeapLocker locker(lock());
2549 _free_set->rebuild();
2550 }
2551 }
2552
2553 #ifdef ASSERT
2554 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2555 _lock.assert_owned_by_current_thread();
2556 }
2557
2558 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2559 _lock.assert_not_owned_by_current_thread();
2560 }
2561
2562 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2563 _lock.assert_owned_by_current_thread_or_safepoint();
2564 }
2565 #endif
2566
2567 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2568 print_on(st);
2569 print_heap_regions_on(st);
2570 }
2571
2572 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2573 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2574
2575 size_t regions_from = _bitmap_regions_per_slice * slice;
2576 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2577 for (size_t g = regions_from; g < regions_to; g++) {
2578 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2579 if (skip_self && g == r->region_number()) continue;
2580 if (get_region(g)->is_committed()) {
2581 return true;
2582 }
2583 }
2584 return false;
2585 }
2586
2587 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2588 assert_heaplock_owned_by_current_thread();
2589
2590 // Bitmaps in special regions do not need commits
2591 if (_bitmap_region_special) {
2592 return true;
2593 }
2594
2595 if (is_bitmap_slice_committed(r, true)) {
2596 // Some other region from the group is already committed, meaning the bitmap
2597 // slice is already committed, we exit right away.
2598 return true;
2599 }
2600
2601 // Commit the bitmap slice:
2602 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2603 size_t off = _bitmap_bytes_per_slice * slice;
2604 size_t len = _bitmap_bytes_per_slice;
2605 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2606 return false;
2607 }
2608 return true;
2609 }
2610
2611 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2612 assert_heaplock_owned_by_current_thread();
2613
2614 // Bitmaps in special regions do not need uncommits
2615 if (_bitmap_region_special) {
2616 return true;
2617 }
2618
2619 if (is_bitmap_slice_committed(r, true)) {
2620 // Some other region from the group is still committed, meaning the bitmap
2621 // slice is should stay committed, exit right away.
2622 return true;
2623 }
2624
2625 // Uncommit the bitmap slice:
2626 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2627 size_t off = _bitmap_bytes_per_slice * slice;
2628 size_t len = _bitmap_bytes_per_slice;
2629 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2630 return false;
2631 }
2632 return true;
2633 }
2634
2635 void ShenandoahHeap::safepoint_synchronize_begin() {
2636 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2637 SuspendibleThreadSet::synchronize();
2638 }
2639 }
2640
2641 void ShenandoahHeap::safepoint_synchronize_end() {
2642 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2643 SuspendibleThreadSet::desynchronize();
2644 }
2645 }
2646
2647 void ShenandoahHeap::vmop_entry_init_mark() {
2648 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2649 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2650 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2651
2652 try_inject_alloc_failure();
2653 VM_ShenandoahInitMark op;
2654 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2655 }
2656
2657 void ShenandoahHeap::vmop_entry_final_mark() {
2658 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2659 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2660 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2661
2662 try_inject_alloc_failure();
2663 VM_ShenandoahFinalMarkStartEvac op;
2664 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2665 }
2666
2667 void ShenandoahHeap::vmop_entry_final_evac() {
2668 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2669 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2670 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2671
2672 VM_ShenandoahFinalEvac op;
2673 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2674 }
2675
2676 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2677 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2678 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2679 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2680
2681 try_inject_alloc_failure();
2682 VM_ShenandoahInitUpdateRefs op;
2683 VMThread::execute(&op);
2684 }
2685
2686 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2687 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2688 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2689 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2690
2691 try_inject_alloc_failure();
2692 VM_ShenandoahFinalUpdateRefs op;
2693 VMThread::execute(&op);
2694 }
2695
2696 void ShenandoahHeap::vmop_entry_init_traversal() {
2697 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2698 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2699 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2700
2701 try_inject_alloc_failure();
2702 VM_ShenandoahInitTraversalGC op;
2703 VMThread::execute(&op);
2704 }
2705
2706 void ShenandoahHeap::vmop_entry_final_traversal() {
2707 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2708 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2709 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2710
2711 try_inject_alloc_failure();
2712 VM_ShenandoahFinalTraversalGC op;
2713 VMThread::execute(&op);
2714 }
2715
2716 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2717 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2718 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2719 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2720
2721 try_inject_alloc_failure();
2722 VM_ShenandoahFullGC op(cause);
2723 VMThread::execute(&op);
2724 }
2725
2726 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2727 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2728 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2729 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2730
2731 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2732 VMThread::execute(°enerated_gc);
2733 }
2734
2735 void ShenandoahHeap::entry_init_mark() {
2736 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2737 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2738 const char* msg = init_mark_event_message();
2739 GCTraceTime(Info, gc) time(msg, gc_timer());
2740 EventMark em("%s", msg);
2741
2742 ShenandoahWorkerScope scope(workers(),
2743 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2744 "init marking");
2745
2746 op_init_mark();
2747 }
2748
2749 void ShenandoahHeap::entry_final_mark() {
2750 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2751 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2752 const char* msg = final_mark_event_message();
2753 GCTraceTime(Info, gc) time(msg, gc_timer());
2754 EventMark em("%s", msg);
2755
2756 ShenandoahWorkerScope scope(workers(),
2757 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2758 "final marking");
2759
2760 op_final_mark();
2761 }
2762
2763 void ShenandoahHeap::entry_final_evac() {
2764 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2765 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2766 static const char* msg = "Pause Final Evac";
2767 GCTraceTime(Info, gc) time(msg, gc_timer());
2768 EventMark em("%s", msg);
2769
2770 op_final_evac();
2771 }
2772
2773 void ShenandoahHeap::entry_init_updaterefs() {
2774 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2775 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2776
2777 static const char* msg = "Pause Init Update Refs";
2778 GCTraceTime(Info, gc) time(msg, gc_timer());
2779 EventMark em("%s", msg);
2780
2781 // No workers used in this phase, no setup required
2782
2783 op_init_updaterefs();
2784 }
2785
2786 void ShenandoahHeap::entry_final_updaterefs() {
2787 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2788 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2789
2790 static const char* msg = "Pause Final Update Refs";
2791 GCTraceTime(Info, gc) time(msg, gc_timer());
2792 EventMark em("%s", msg);
2793
2794 ShenandoahWorkerScope scope(workers(),
2795 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2796 "final reference update");
2797
2798 op_final_updaterefs();
2799 }
2800
2801 void ShenandoahHeap::entry_init_traversal() {
2802 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2803 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2804
2805 static const char* msg = init_traversal_event_message();
2806 GCTraceTime(Info, gc) time(msg, gc_timer());
2807 EventMark em("%s", msg);
2808
2809 ShenandoahWorkerScope scope(workers(),
2810 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2811 "init traversal");
2812
2813 op_init_traversal();
2814 }
2815
2816 void ShenandoahHeap::entry_final_traversal() {
2817 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2818 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2819
2820 static const char* msg = final_traversal_event_message();
2821 GCTraceTime(Info, gc) time(msg, gc_timer());
2822 EventMark em("%s", msg);
2823
2824 ShenandoahWorkerScope scope(workers(),
2825 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2826 "final traversal");
2827
2828 op_final_traversal();
2829 }
2830
2831 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2832 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2833 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2834
2835 static const char* msg = "Pause Full";
2836 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2837 EventMark em("%s", msg);
2838
2839 ShenandoahWorkerScope scope(workers(),
2840 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2841 "full gc");
2842
2843 op_full(cause);
2844 }
2845
2846 void ShenandoahHeap::entry_degenerated(int point) {
2847 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2848 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2849
2850 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2851 const char* msg = degen_event_message(dpoint);
2852 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2853 EventMark em("%s", msg);
2854
2855 ShenandoahWorkerScope scope(workers(),
2856 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2857 "stw degenerated gc");
2858
2859 set_degenerated_gc_in_progress(true);
2860 op_degenerated(dpoint);
2861 set_degenerated_gc_in_progress(false);
2862 }
2863
2864 void ShenandoahHeap::entry_mark() {
2865 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2866
2867 const char* msg = conc_mark_event_message();
2868 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2869 EventMark em("%s", msg);
2870
2871 ShenandoahWorkerScope scope(workers(),
2872 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2873 "concurrent marking");
2874
2875 try_inject_alloc_failure();
2876 op_mark();
2877 }
2878
2879 void ShenandoahHeap::entry_evac() {
2880 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2881 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2882
2883 static const char* msg = "Concurrent evacuation";
2884 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2885 EventMark em("%s", msg);
2886
2887 ShenandoahWorkerScope scope(workers(),
2888 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2889 "concurrent evacuation");
2890
2891 try_inject_alloc_failure();
2892 op_conc_evac();
2893 }
2894
2895 void ShenandoahHeap::entry_updaterefs() {
2896 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2897
2898 static const char* msg = "Concurrent update references";
2899 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2900 EventMark em("%s", msg);
2901
2902 ShenandoahWorkerScope scope(workers(),
2903 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2904 "concurrent reference update");
2905
2906 try_inject_alloc_failure();
2907 op_updaterefs();
2908 }
2909
2910 void ShenandoahHeap::entry_roots() {
2911 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots);
2912
2913 static const char* msg = "Concurrent roots processing";
2914 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2915 EventMark em("%s", msg);
2916
2917 ShenandoahWorkerScope scope(workers(),
2918 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(),
2919 "concurrent root processing");
2920
2921 try_inject_alloc_failure();
2922 op_roots();
2923 }
2924
2925 void ShenandoahHeap::entry_cleanup() {
2926 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2927
2928 static const char* msg = "Concurrent cleanup";
2929 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2930 EventMark em("%s", msg);
2931
2932 // This phase does not use workers, no need for setup
2933
2934 try_inject_alloc_failure();
2935 op_cleanup();
2936 }
2937
2938 void ShenandoahHeap::entry_reset() {
2939 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2940
2941 static const char* msg = "Concurrent reset";
2942 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2943 EventMark em("%s", msg);
2944
2945 ShenandoahWorkerScope scope(workers(),
2946 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2947 "concurrent reset");
2948
2949 try_inject_alloc_failure();
2950 op_reset();
2951 }
2952
2953 void ShenandoahHeap::entry_preclean() {
2954 if (ShenandoahPreclean && process_references()) {
2955 static const char* msg = "Concurrent precleaning";
2956 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2957 EventMark em("%s", msg);
2958
2959 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2960
2961 ShenandoahWorkerScope scope(workers(),
2962 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2963 "concurrent preclean",
2964 /* check_workers = */ false);
2965
2966 try_inject_alloc_failure();
2967 op_preclean();
2968 }
2969 }
2970
2971 void ShenandoahHeap::entry_traversal() {
2972 static const char* msg = conc_traversal_event_message();
2973 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2974 EventMark em("%s", msg);
2975
2976 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2977
2978 ShenandoahWorkerScope scope(workers(),
2979 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2980 "concurrent traversal");
2981
2982 try_inject_alloc_failure();
2983 op_traversal();
2984 }
2985
2986 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2987 static const char *msg = "Concurrent uncommit";
2988 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2989 EventMark em("%s", msg);
2990
2991 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2992
2993 op_uncommit(shrink_before);
2994 }
2995
2996 void ShenandoahHeap::try_inject_alloc_failure() {
2997 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2998 _inject_alloc_failure.set();
2999 os::naked_short_sleep(1);
3000 if (cancelled_gc()) {
3001 log_info(gc)("Allocation failure was successfully injected");
3002 }
3003 }
3004 }
3005
3006 bool ShenandoahHeap::should_inject_alloc_failure() {
3007 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
3008 }
3009
3010 void ShenandoahHeap::initialize_serviceability() {
3011 _memory_pool = new ShenandoahMemoryPool(this);
3012 _cycle_memory_manager.add_pool(_memory_pool);
3013 _stw_memory_manager.add_pool(_memory_pool);
3014 }
3015
3016 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
3017 GrowableArray<GCMemoryManager*> memory_managers(2);
3018 memory_managers.append(&_cycle_memory_manager);
3019 memory_managers.append(&_stw_memory_manager);
3020 return memory_managers;
3021 }
3022
3023 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
3024 GrowableArray<MemoryPool*> memory_pools(1);
3025 memory_pools.append(_memory_pool);
3026 return memory_pools;
3027 }
3028
3029 MemoryUsage ShenandoahHeap::memory_usage() {
3030 return _memory_pool->get_memory_usage();
3031 }
3032
3033 void ShenandoahHeap::enter_evacuation() {
3034 _oom_evac_handler.enter_evacuation();
3035 }
3036
3037 void ShenandoahHeap::leave_evacuation() {
3038 _oom_evac_handler.leave_evacuation();
3039 }
3040
3041 ShenandoahRegionIterator::ShenandoahRegionIterator() :
3042 _heap(ShenandoahHeap::heap()),
3043 _index(0) {}
3044
3045 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
3046 _heap(heap),
3047 _index(0) {}
3048
3049 void ShenandoahRegionIterator::reset() {
3050 _index = 0;
3051 }
3052
3053 bool ShenandoahRegionIterator::has_next() const {
3054 return _index < _heap->num_regions();
3055 }
3056
3057 char ShenandoahHeap::gc_state() const {
3058 return _gc_state.raw_value();
3059 }
3060
3061 void ShenandoahHeap::deduplicate_string(oop str) {
3062 assert(java_lang_String::is_instance(str), "invariant");
3063
3064 if (ShenandoahStringDedup::is_enabled()) {
3065 ShenandoahStringDedup::deduplicate(str);
3066 }
3067 }
3068
3069 const char* ShenandoahHeap::init_mark_event_message() const {
3070 bool update_refs = has_forwarded_objects();
3071 bool proc_refs = process_references();
3072 bool unload_cls = unload_classes();
3073
3074 if (update_refs && proc_refs && unload_cls) {
3075 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
3076 } else if (update_refs && proc_refs) {
3077 return "Pause Init Mark (update refs) (process weakrefs)";
3078 } else if (update_refs && unload_cls) {
3079 return "Pause Init Mark (update refs) (unload classes)";
3080 } else if (proc_refs && unload_cls) {
3081 return "Pause Init Mark (process weakrefs) (unload classes)";
3082 } else if (update_refs) {
3083 return "Pause Init Mark (update refs)";
3084 } else if (proc_refs) {
3085 return "Pause Init Mark (process weakrefs)";
3086 } else if (unload_cls) {
3087 return "Pause Init Mark (unload classes)";
3088 } else {
3089 return "Pause Init Mark";
3090 }
3091 }
3092
3093 const char* ShenandoahHeap::final_mark_event_message() const {
3094 bool update_refs = has_forwarded_objects();
3095 bool proc_refs = process_references();
3096 bool unload_cls = unload_classes();
3097
3098 if (update_refs && proc_refs && unload_cls) {
3099 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
3100 } else if (update_refs && proc_refs) {
3101 return "Pause Final Mark (update refs) (process weakrefs)";
3102 } else if (update_refs && unload_cls) {
3103 return "Pause Final Mark (update refs) (unload classes)";
3104 } else if (proc_refs && unload_cls) {
3105 return "Pause Final Mark (process weakrefs) (unload classes)";
3106 } else if (update_refs) {
3107 return "Pause Final Mark (update refs)";
3108 } else if (proc_refs) {
3109 return "Pause Final Mark (process weakrefs)";
3110 } else if (unload_cls) {
3111 return "Pause Final Mark (unload classes)";
3112 } else {
3113 return "Pause Final Mark";
3114 }
3115 }
3116
3117 const char* ShenandoahHeap::conc_mark_event_message() const {
3118 bool update_refs = has_forwarded_objects();
3119 bool proc_refs = process_references();
3120 bool unload_cls = unload_classes();
3121
3122 if (update_refs && proc_refs && unload_cls) {
3123 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
3124 } else if (update_refs && proc_refs) {
3125 return "Concurrent marking (update refs) (process weakrefs)";
3126 } else if (update_refs && unload_cls) {
3127 return "Concurrent marking (update refs) (unload classes)";
3128 } else if (proc_refs && unload_cls) {
3129 return "Concurrent marking (process weakrefs) (unload classes)";
3130 } else if (update_refs) {
3131 return "Concurrent marking (update refs)";
3132 } else if (proc_refs) {
3133 return "Concurrent marking (process weakrefs)";
3134 } else if (unload_cls) {
3135 return "Concurrent marking (unload classes)";
3136 } else {
3137 return "Concurrent marking";
3138 }
3139 }
3140
3141 const char* ShenandoahHeap::init_traversal_event_message() const {
3142 bool proc_refs = process_references();
3143 bool unload_cls = unload_classes();
3144
3145 if (proc_refs && unload_cls) {
3146 return "Pause Init Traversal (process weakrefs) (unload classes)";
3147 } else if (proc_refs) {
3148 return "Pause Init Traversal (process weakrefs)";
3149 } else if (unload_cls) {
3150 return "Pause Init Traversal (unload classes)";
3151 } else {
3152 return "Pause Init Traversal";
3153 }
3154 }
3155
3156 const char* ShenandoahHeap::final_traversal_event_message() const {
3157 bool proc_refs = process_references();
3158 bool unload_cls = unload_classes();
3159
3160 if (proc_refs && unload_cls) {
3161 return "Pause Final Traversal (process weakrefs) (unload classes)";
3162 } else if (proc_refs) {
3163 return "Pause Final Traversal (process weakrefs)";
3164 } else if (unload_cls) {
3165 return "Pause Final Traversal (unload classes)";
3166 } else {
3167 return "Pause Final Traversal";
3168 }
3169 }
3170
3171 const char* ShenandoahHeap::conc_traversal_event_message() const {
3172 bool proc_refs = process_references();
3173 bool unload_cls = unload_classes();
3174
3175 if (proc_refs && unload_cls) {
3176 return "Concurrent Traversal (process weakrefs) (unload classes)";
3177 } else if (proc_refs) {
3178 return "Concurrent Traversal (process weakrefs)";
3179 } else if (unload_cls) {
3180 return "Concurrent Traversal (unload classes)";
3181 } else {
3182 return "Concurrent Traversal";
3183 }
3184 }
3185
3186 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
3187 switch (point) {
3188 case _degenerated_unset:
3189 return "Pause Degenerated GC (<UNSET>)";
3190 case _degenerated_traversal:
3191 return "Pause Degenerated GC (Traversal)";
3192 case _degenerated_outside_cycle:
3193 return "Pause Degenerated GC (Outside of Cycle)";
3194 case _degenerated_mark:
3195 return "Pause Degenerated GC (Mark)";
3196 case _degenerated_evac:
3197 return "Pause Degenerated GC (Evacuation)";
3198 case _degenerated_updaterefs:
3199 return "Pause Degenerated GC (Update Refs)";
3200 default:
3201 ShouldNotReachHere();
3202 return "ERROR";
3203 }
3204 }
3205
3206 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
3207 #ifdef ASSERT
3208 assert(_liveness_cache != NULL, "sanity");
3209 assert(worker_id < _max_workers, "sanity");
3210 for (uint i = 0; i < num_regions(); i++) {
3211 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
3212 }
3213 #endif
3214 return _liveness_cache[worker_id];
3215 }
3216
3217 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
3218 assert(worker_id < _max_workers, "sanity");
3219 assert(_liveness_cache != NULL, "sanity");
3220 jushort* ld = _liveness_cache[worker_id];
3221 for (uint i = 0; i < num_regions(); i++) {
3222 ShenandoahHeapRegion* r = get_region(i);
3223 jushort live = ld[i];
3224 if (live > 0) {
3225 r->increase_live_data_gc_words(live);
3226 ld[i] = 0;
3227 }
3228 }
3229 }