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/shenandoahObjectMarker.hpp"
57 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
58 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
59 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp"
60 #include "gc/shenandoah/shenandoahPassiveMode.hpp"
61 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp"
62 #include "gc/shenandoah/shenandoahStringDedup.hpp"
63 #include "gc/shenandoah/shenandoahTaskqueue.hpp"
64 #include "gc/shenandoah/shenandoahTraversalMode.hpp"
65 #include "gc/shenandoah/shenandoahUtils.hpp"
66 #include "gc/shenandoah/shenandoahVerifier.hpp"
67 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
68 #include "gc/shenandoah/shenandoahVMOperations.hpp"
69 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
70 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
71 #if INCLUDE_JFR
72 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
73 #endif
74
75 #include "memory/metaspace.hpp"
76 #include "oops/compressedOops.inline.hpp"
77 #include "runtime/atomic.hpp"
78 #include "runtime/globals.hpp"
79 #include "runtime/interfaceSupport.inline.hpp"
80 #include "runtime/orderAccess.hpp"
81 #include "runtime/safepointMechanism.hpp"
82 #include "runtime/vmThread.hpp"
83 #include "services/mallocTracker.hpp"
84 #include "utilities/powerOfTwo.hpp"
85
86 #ifdef ASSERT
87 template <class T>
88 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
89 T o = RawAccess<>::oop_load(p);
90 if (! CompressedOops::is_null(o)) {
91 oop obj = CompressedOops::decode_not_null(o);
92 shenandoah_assert_not_forwarded(p, obj);
93 }
94 }
95
96 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
97 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
98 #endif
99
100 class ShenandoahPretouchHeapTask : public AbstractGangTask {
101 private:
102 ShenandoahRegionIterator _regions;
103 const size_t _page_size;
104 public:
105 ShenandoahPretouchHeapTask(size_t page_size) :
106 AbstractGangTask("Shenandoah Pretouch Heap"),
107 _page_size(page_size) {}
108
109 virtual void work(uint worker_id) {
110 ShenandoahHeapRegion* r = _regions.next();
111 while (r != NULL) {
112 os::pretouch_memory(r->bottom(), r->end(), _page_size);
113 r = _regions.next();
114 }
115 }
116 };
117
118 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
119 private:
120 ShenandoahRegionIterator _regions;
121 char* _bitmap_base;
122 const size_t _bitmap_size;
123 const size_t _page_size;
124 public:
125 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
126 AbstractGangTask("Shenandoah Pretouch Bitmap"),
127 _bitmap_base(bitmap_base),
128 _bitmap_size(bitmap_size),
129 _page_size(page_size) {}
130
131 virtual void work(uint worker_id) {
132 ShenandoahHeapRegion* r = _regions.next();
133 while (r != NULL) {
134 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
135 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
136 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
137
138 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
139
140 r = _regions.next();
141 }
142 }
143 };
144
145 jint ShenandoahHeap::initialize() {
146 initialize_heuristics();
147
148 //
149 // Figure out heap sizing
150 //
151
152 size_t init_byte_size = InitialHeapSize;
153 size_t min_byte_size = MinHeapSize;
154 size_t max_byte_size = MaxHeapSize;
155 size_t heap_alignment = HeapAlignment;
156
157 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
158
159 if (ShenandoahAlwaysPreTouch) {
160 // Enabled pre-touch means the entire heap is committed right away.
161 init_byte_size = max_byte_size;
162 }
163
164 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
165 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
166
167 _num_regions = ShenandoahHeapRegion::region_count();
168
169 size_t num_committed_regions = init_byte_size / reg_size_bytes;
170 num_committed_regions = MIN2(num_committed_regions, _num_regions);
171 assert(num_committed_regions <= _num_regions, "sanity");
172 _initial_size = num_committed_regions * reg_size_bytes;
173
174 size_t num_min_regions = min_byte_size / reg_size_bytes;
175 num_min_regions = MIN2(num_min_regions, _num_regions);
176 assert(num_min_regions <= _num_regions, "sanity");
177 _minimum_size = num_min_regions * reg_size_bytes;
178
179 _committed = _initial_size;
180
181 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
182 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
183
184 //
185 // Reserve and commit memory for heap
186 //
187
188 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
189 initialize_reserved_region(heap_rs);
190 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
191 _heap_region_special = heap_rs.special();
192
193 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
194 "Misaligned heap: " PTR_FORMAT, p2i(base()));
195
196 #if SHENANDOAH_OPTIMIZED_OBJTASK
197 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits.
198 // Fail if we ever attempt to address more than we can.
199 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) {
200 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n"
201 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n"
202 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).",
203 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable());
204 vm_exit_during_initialization("Fatal Error", buf);
205 }
206 #endif
207
208 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
209 if (!_heap_region_special) {
210 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
211 "Cannot commit heap memory");
212 }
213
214 //
215 // Reserve and commit memory for bitmap(s)
216 //
217
218 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
219 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
220
221 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
222
223 guarantee(bitmap_bytes_per_region != 0,
224 "Bitmap bytes per region should not be zero");
225 guarantee(is_power_of_2(bitmap_bytes_per_region),
226 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
227
228 if (bitmap_page_size > bitmap_bytes_per_region) {
229 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
230 _bitmap_bytes_per_slice = bitmap_page_size;
231 } else {
232 _bitmap_regions_per_slice = 1;
233 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
234 }
235
236 guarantee(_bitmap_regions_per_slice >= 1,
237 "Should have at least one region per slice: " SIZE_FORMAT,
238 _bitmap_regions_per_slice);
239
240 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
241 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
242 _bitmap_bytes_per_slice, bitmap_page_size);
243
244 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
245 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
246 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
247 _bitmap_region_special = bitmap.special();
248
249 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
250 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
251 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
252 if (!_bitmap_region_special) {
253 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
254 "Cannot commit bitmap memory");
255 }
256
257 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
258
259 if (ShenandoahVerify) {
260 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
261 if (!verify_bitmap.special()) {
262 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
263 "Cannot commit verification bitmap memory");
264 }
265 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
266 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
267 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
268 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
269 }
270
271 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
272 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
273 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
274 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
275 _aux_bitmap_region_special = aux_bitmap.special();
276 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
277
278 //
279 // Create regions and region sets
280 //
281
282 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
283 _free_set = new ShenandoahFreeSet(this, _num_regions);
284 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
285
286 {
287 ShenandoahHeapLocker locker(lock());
288
289 size_t size_words = ShenandoahHeapRegion::region_size_words();
290
291 for (size_t i = 0; i < _num_regions; i++) {
292 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
293 bool is_committed = i < num_committed_regions;
294 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
295
296 _marking_context->initialize_top_at_mark_start(r);
297 _regions[i] = r;
298 assert(!collection_set()->is_in(i), "New region should not be in collection set");
299 }
300
301 // Initialize to complete
302 _marking_context->mark_complete();
303
304 _free_set->rebuild();
305 }
306
307 if (ShenandoahAlwaysPreTouch) {
308 assert(!AlwaysPreTouch, "Should have been overridden");
309
310 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
311 // before initialize() below zeroes it with initializing thread. For any given region,
312 // we touch the region and the corresponding bitmaps from the same thread.
313 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
314
315 size_t pretouch_heap_page_size = heap_page_size;
316 size_t pretouch_bitmap_page_size = bitmap_page_size;
317
318 #ifdef LINUX
319 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
320 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
321 // them into huge one. Therefore, we need to pretouch with smaller pages.
322 if (UseTransparentHugePages) {
323 pretouch_heap_page_size = (size_t)os::vm_page_size();
324 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
325 }
326 #endif
327
328 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
329 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
330
331 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
332 _num_regions, pretouch_bitmap_page_size);
333 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
334 _workers->run_task(&bcl);
335
336 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
337 _num_regions, pretouch_heap_page_size);
338 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
339 _workers->run_task(&hcl);
340 }
341
342 //
343 // Initialize the rest of GC subsystems
344 //
345
346 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
347 for (uint worker = 0; worker < _max_workers; worker++) {
348 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
349 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
350 }
351
352 // There should probably be Shenandoah-specific options for these,
353 // just as there are G1-specific options.
354 {
355 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set();
356 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold
357 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent
358 }
359
360 _monitoring_support = new ShenandoahMonitoringSupport(this);
361 _phase_timings = new ShenandoahPhaseTimings();
362 ShenandoahStringDedup::initialize();
363 ShenandoahCodeRoots::initialize();
364
365 if (ShenandoahAllocationTrace) {
366 _alloc_tracker = new ShenandoahAllocTracker();
367 }
368
369 if (ShenandoahPacing) {
370 _pacer = new ShenandoahPacer(this);
371 _pacer->setup_for_idle();
372 } else {
373 _pacer = NULL;
374 }
375
376 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ?
377 new ShenandoahTraversalGC(this, _num_regions) :
378 NULL;
379
380 _control_thread = new ShenandoahControlThread();
381
382 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
383 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
384 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
385 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
386 );
387
388 log_info(gc, init)("Safepointing mechanism: %s",
389 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
390 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
391
392 return JNI_OK;
393 }
394
395 void ShenandoahHeap::initialize_heuristics() {
396 if (ShenandoahGCMode != NULL) {
397 if (strcmp(ShenandoahGCMode, "traversal") == 0) {
398 _gc_mode = new ShenandoahTraversalMode();
399 } else if (strcmp(ShenandoahGCMode, "normal") == 0) {
400 _gc_mode = new ShenandoahNormalMode();
401 } else if (strcmp(ShenandoahGCMode, "passive") == 0) {
402 _gc_mode = new ShenandoahPassiveMode();
403 } else {
404 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option");
405 }
406 } else {
407 ShouldNotReachHere();
408 }
409 _gc_mode->initialize_flags();
410 _heuristics = _gc_mode->initialize_heuristics();
411
412 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
413 vm_exit_during_initialization(
414 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
415 _heuristics->name()));
416 }
417 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
418 vm_exit_during_initialization(
419 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
420 _heuristics->name()));
421 }
422 log_info(gc, init)("Shenandoah heuristics: %s",
423 _heuristics->name());
424 }
425
426 #ifdef _MSC_VER
427 #pragma warning( push )
428 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
429 #endif
430
431 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
432 CollectedHeap(),
433 _initial_size(0),
434 _used(0),
435 _committed(0),
436 _bytes_allocated_since_gc_start(0),
437 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
438 _workers(NULL),
439 _safepoint_workers(NULL),
440 _heap_region_special(false),
441 _num_regions(0),
442 _regions(NULL),
443 _update_refs_iterator(this),
444 _control_thread(NULL),
445 _shenandoah_policy(policy),
446 _heuristics(NULL),
447 _free_set(NULL),
448 _scm(new ShenandoahConcurrentMark()),
449 _traversal_gc(NULL),
450 _full_gc(new ShenandoahMarkCompact()),
451 _pacer(NULL),
452 _verifier(NULL),
453 _alloc_tracker(NULL),
454 _phase_timings(NULL),
455 _monitoring_support(NULL),
456 _memory_pool(NULL),
457 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
458 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
459 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
460 _soft_ref_policy(),
461 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
462 _ref_processor(NULL),
463 _marking_context(NULL),
464 _bitmap_size(0),
465 _bitmap_regions_per_slice(0),
466 _bitmap_bytes_per_slice(0),
467 _bitmap_region_special(false),
468 _aux_bitmap_region_special(false),
469 _liveness_cache(NULL),
470 _collection_set(NULL)
471 {
472 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
473 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
474
475 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
476
477 _max_workers = MAX2(_max_workers, 1U);
478 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
479 /* are_GC_task_threads */ true,
480 /* are_ConcurrentGC_threads */ true);
481 if (_workers == NULL) {
482 vm_exit_during_initialization("Failed necessary allocation.");
483 } else {
484 _workers->initialize_workers();
485 }
486
487 if (ShenandoahParallelSafepointThreads > 1) {
488 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
489 ShenandoahParallelSafepointThreads,
490 /* are_GC_task_threads */ false,
491 /* are_ConcurrentGC_threads */ false);
492 _safepoint_workers->initialize_workers();
493 }
494 }
495
496 #ifdef _MSC_VER
497 #pragma warning( pop )
498 #endif
499
500 class ShenandoahResetBitmapTask : public AbstractGangTask {
501 private:
502 ShenandoahRegionIterator _regions;
503
504 public:
505 ShenandoahResetBitmapTask() :
506 AbstractGangTask("Parallel Reset Bitmap Task") {}
507
508 void work(uint worker_id) {
509 ShenandoahHeapRegion* region = _regions.next();
510 ShenandoahHeap* heap = ShenandoahHeap::heap();
511 ShenandoahMarkingContext* const ctx = heap->marking_context();
512 while (region != NULL) {
513 if (heap->is_bitmap_slice_committed(region)) {
514 ctx->clear_bitmap(region);
515 }
516 region = _regions.next();
517 }
518 }
519 };
520
521 void ShenandoahHeap::reset_mark_bitmap() {
522 assert_gc_workers(_workers->active_workers());
523 mark_incomplete_marking_context();
524
525 ShenandoahResetBitmapTask task;
526 _workers->run_task(&task);
527 }
528
529 void ShenandoahHeap::print_on(outputStream* st) const {
530 st->print_cr("Shenandoah Heap");
531 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used",
532 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()),
533 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()),
534 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used()));
535 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions",
536 num_regions(),
537 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()),
538 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes()));
539
540 st->print("Status: ");
541 if (has_forwarded_objects()) st->print("has forwarded objects, ");
542 if (is_concurrent_mark_in_progress()) st->print("marking, ");
543 if (is_evacuation_in_progress()) st->print("evacuating, ");
544 if (is_update_refs_in_progress()) st->print("updating refs, ");
545 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
546 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
547 if (is_full_gc_in_progress()) st->print("full gc, ");
548 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
549 if (is_concurrent_root_in_progress()) st->print("concurrent roots, ");
550
551 if (cancelled_gc()) {
552 st->print("cancelled");
553 } else {
554 st->print("not cancelled");
555 }
556 st->cr();
557
558 st->print_cr("Reserved region:");
559 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
560 p2i(reserved_region().start()),
561 p2i(reserved_region().end()));
562
563 ShenandoahCollectionSet* cset = collection_set();
564 st->print_cr("Collection set:");
565 if (cset != NULL) {
566 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
567 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
568 } else {
569 st->print_cr(" (NULL)");
570 }
571
572 st->cr();
573 MetaspaceUtils::print_on(st);
574
575 if (Verbose) {
576 print_heap_regions_on(st);
577 }
578 }
579
580 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
581 public:
582 void do_thread(Thread* thread) {
583 assert(thread != NULL, "Sanity");
584 assert(thread->is_Worker_thread(), "Only worker thread expected");
585 ShenandoahThreadLocalData::initialize_gclab(thread);
586 }
587 };
588
589 void ShenandoahHeap::post_initialize() {
590 CollectedHeap::post_initialize();
591 MutexLocker ml(Threads_lock);
592
593 ShenandoahInitWorkerGCLABClosure init_gclabs;
594 _workers->threads_do(&init_gclabs);
595
596 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
597 // Now, we will let WorkGang to initialize gclab when new worker is created.
598 _workers->set_initialize_gclab();
599
600 _scm->initialize(_max_workers);
601 _full_gc->initialize(_gc_timer);
602
603 ref_processing_init();
604
605 _heuristics->initialize();
606
607 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers());
608 }
609
610 size_t ShenandoahHeap::used() const {
611 return Atomic::load_acquire(&_used);
612 }
613
614 size_t ShenandoahHeap::committed() const {
615 OrderAccess::acquire();
616 return _committed;
617 }
618
619 void ShenandoahHeap::increase_committed(size_t bytes) {
620 assert_heaplock_or_safepoint();
621 _committed += bytes;
622 }
623
624 void ShenandoahHeap::decrease_committed(size_t bytes) {
625 assert_heaplock_or_safepoint();
626 _committed -= bytes;
627 }
628
629 void ShenandoahHeap::increase_used(size_t bytes) {
630 Atomic::add(&_used, bytes);
631 }
632
633 void ShenandoahHeap::set_used(size_t bytes) {
634 Atomic::release_store_fence(&_used, bytes);
635 }
636
637 void ShenandoahHeap::decrease_used(size_t bytes) {
638 assert(used() >= bytes, "never decrease heap size by more than we've left");
639 Atomic::sub(&_used, bytes);
640 }
641
642 void ShenandoahHeap::increase_allocated(size_t bytes) {
643 Atomic::add(&_bytes_allocated_since_gc_start, bytes);
644 }
645
646 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
647 size_t bytes = words * HeapWordSize;
648 if (!waste) {
649 increase_used(bytes);
650 }
651 increase_allocated(bytes);
652 if (ShenandoahPacing) {
653 control_thread()->pacing_notify_alloc(words);
654 if (waste) {
655 pacer()->claim_for_alloc(words, true);
656 }
657 }
658 }
659
660 size_t ShenandoahHeap::capacity() const {
661 return committed();
662 }
663
664 size_t ShenandoahHeap::max_capacity() const {
665 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
666 }
667
668 size_t ShenandoahHeap::min_capacity() const {
669 return _minimum_size;
670 }
671
672 size_t ShenandoahHeap::initial_capacity() const {
673 return _initial_size;
674 }
675
676 bool ShenandoahHeap::is_in(const void* p) const {
677 HeapWord* heap_base = (HeapWord*) base();
678 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
679 return p >= heap_base && p < last_region_end;
680 }
681
682 void ShenandoahHeap::op_uncommit(double shrink_before) {
683 assert (ShenandoahUncommit, "should be enabled");
684
685 // Application allocates from the beginning of the heap, and GC allocates at
686 // the end of it. It is more efficient to uncommit from the end, so that applications
687 // could enjoy the near committed regions. GC allocations are much less frequent,
688 // and therefore can accept the committing costs.
689
690 size_t count = 0;
691 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
692 ShenandoahHeapRegion* r = get_region(i - 1);
693 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
694 ShenandoahHeapLocker locker(lock());
695 if (r->is_empty_committed()) {
696 // Do not uncommit below minimal capacity
697 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
698 break;
699 }
700
701 r->make_uncommitted();
702 count++;
703 }
704 }
705 SpinPause(); // allow allocators to take the lock
706 }
707
708 if (count > 0) {
709 control_thread()->notify_heap_changed();
710 }
711 }
712
713 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
714 // New object should fit the GCLAB size
715 size_t min_size = MAX2(size, PLAB::min_size());
716
717 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
718 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
719 new_size = MIN2(new_size, PLAB::max_size());
720 new_size = MAX2(new_size, PLAB::min_size());
721
722 // Record new heuristic value even if we take any shortcut. This captures
723 // the case when moderately-sized objects always take a shortcut. At some point,
724 // heuristics should catch up with them.
725 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
726
727 if (new_size < size) {
728 // New size still does not fit the object. Fall back to shared allocation.
729 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
730 return NULL;
731 }
732
733 // Retire current GCLAB, and allocate a new one.
734 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
735 gclab->retire();
736
737 size_t actual_size = 0;
738 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
739 if (gclab_buf == NULL) {
740 return NULL;
741 }
742
743 assert (size <= actual_size, "allocation should fit");
744
745 if (ZeroTLAB) {
746 // ..and clear it.
747 Copy::zero_to_words(gclab_buf, actual_size);
748 } else {
749 // ...and zap just allocated object.
750 #ifdef ASSERT
751 // Skip mangling the space corresponding to the object header to
752 // ensure that the returned space is not considered parsable by
753 // any concurrent GC thread.
754 size_t hdr_size = oopDesc::header_size();
755 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
756 #endif // ASSERT
757 }
758 gclab->set_buf(gclab_buf, actual_size);
759 return gclab->allocate(size);
760 }
761
762 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
763 size_t requested_size,
764 size_t* actual_size) {
765 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
766 HeapWord* res = allocate_memory(req);
767 if (res != NULL) {
768 *actual_size = req.actual_size();
769 } else {
770 *actual_size = 0;
771 }
772 return res;
773 }
774
775 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
776 size_t word_size,
777 size_t* actual_size) {
778 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
779 HeapWord* res = allocate_memory(req);
780 if (res != NULL) {
781 *actual_size = req.actual_size();
782 } else {
783 *actual_size = 0;
784 }
785 return res;
786 }
787
788 ShenandoahHeap* ShenandoahHeap::heap() {
789 CollectedHeap* heap = Universe::heap();
790 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
791 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
792 return (ShenandoahHeap*) heap;
793 }
794
795 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
796 CollectedHeap* heap = Universe::heap();
797 return (ShenandoahHeap*) heap;
798 }
799
800 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
801 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
802
803 intptr_t pacer_epoch = 0;
804 bool in_new_region = false;
805 HeapWord* result = NULL;
806
807 if (req.is_mutator_alloc()) {
808 if (ShenandoahPacing) {
809 pacer()->pace_for_alloc(req.size());
810 pacer_epoch = pacer()->epoch();
811 }
812
813 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
814 result = allocate_memory_under_lock(req, in_new_region);
815 }
816
817 // Allocation failed, block until control thread reacted, then retry allocation.
818 //
819 // It might happen that one of the threads requesting allocation would unblock
820 // way later after GC happened, only to fail the second allocation, because
821 // other threads have already depleted the free storage. In this case, a better
822 // strategy is to try again, as long as GC makes progress.
823 //
824 // Then, we need to make sure the allocation was retried after at least one
825 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
826
827 size_t tries = 0;
828
829 while (result == NULL && _progress_last_gc.is_set()) {
830 tries++;
831 control_thread()->handle_alloc_failure(req.size());
832 result = allocate_memory_under_lock(req, in_new_region);
833 }
834
835 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
836 tries++;
837 control_thread()->handle_alloc_failure(req.size());
838 result = allocate_memory_under_lock(req, in_new_region);
839 }
840
841 } else {
842 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
843 result = allocate_memory_under_lock(req, in_new_region);
844 // Do not call handle_alloc_failure() here, because we cannot block.
845 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
846 }
847
848 if (in_new_region) {
849 control_thread()->notify_heap_changed();
850 }
851
852 if (result != NULL) {
853 size_t requested = req.size();
854 size_t actual = req.actual_size();
855
856 assert (req.is_lab_alloc() || (requested == actual),
857 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
858 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
859
860 if (req.is_mutator_alloc()) {
861 notify_mutator_alloc_words(actual, false);
862
863 // If we requested more than we were granted, give the rest back to pacer.
864 // This only matters if we are in the same pacing epoch: do not try to unpace
865 // over the budget for the other phase.
866 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
867 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
868 }
869 } else {
870 increase_used(actual*HeapWordSize);
871 }
872 }
873
874 return result;
875 }
876
877 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
878 ShenandoahHeapLocker locker(lock());
879 return _free_set->allocate(req, in_new_region);
880 }
881
882 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
883 bool* gc_overhead_limit_was_exceeded) {
884 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
885 return allocate_memory(req);
886 }
887
888 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
889 size_t size,
890 Metaspace::MetadataType mdtype) {
891 MetaWord* result;
892
893 // Inform metaspace OOM to GC heuristics if class unloading is possible.
894 if (heuristics()->can_unload_classes()) {
895 ShenandoahHeuristics* h = heuristics();
896 h->record_metaspace_oom();
897 }
898
899 // Expand and retry allocation
900 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
901 if (result != NULL) {
902 return result;
903 }
904
905 // Start full GC
906 collect(GCCause::_metadata_GC_clear_soft_refs);
907
908 // Retry allocation
909 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
910 if (result != NULL) {
911 return result;
912 }
913
914 // Expand and retry allocation
915 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
916 if (result != NULL) {
917 return result;
918 }
919
920 // Out of memory
921 return NULL;
922 }
923
924 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
925 private:
926 ShenandoahHeap* const _heap;
927 Thread* const _thread;
928 public:
929 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
930 _heap(heap), _thread(Thread::current()) {}
931
932 void do_object(oop p) {
933 shenandoah_assert_marked(NULL, p);
934 if (!p->is_forwarded()) {
935 _heap->evacuate_object(p, _thread);
936 }
937 }
938 };
939
940 class ShenandoahEvacuationTask : public AbstractGangTask {
941 private:
942 ShenandoahHeap* const _sh;
943 ShenandoahCollectionSet* const _cs;
944 bool _concurrent;
945 public:
946 ShenandoahEvacuationTask(ShenandoahHeap* sh,
947 ShenandoahCollectionSet* cs,
948 bool concurrent) :
949 AbstractGangTask("Parallel Evacuation Task"),
950 _sh(sh),
951 _cs(cs),
952 _concurrent(concurrent)
953 {}
954
955 void work(uint worker_id) {
956 if (_concurrent) {
957 ShenandoahConcurrentWorkerSession worker_session(worker_id);
958 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
959 ShenandoahEvacOOMScope oom_evac_scope;
960 do_work();
961 } else {
962 ShenandoahParallelWorkerSession worker_session(worker_id);
963 ShenandoahEvacOOMScope oom_evac_scope;
964 do_work();
965 }
966 }
967
968 private:
969 void do_work() {
970 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
971 ShenandoahHeapRegion* r;
972 while ((r =_cs->claim_next()) != NULL) {
973 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->region_number());
974 _sh->marked_object_iterate(r, &cl);
975
976 if (ShenandoahPacing) {
977 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
978 }
979
980 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
981 break;
982 }
983 }
984 }
985 };
986
987 void ShenandoahHeap::trash_cset_regions() {
988 ShenandoahHeapLocker locker(lock());
989
990 ShenandoahCollectionSet* set = collection_set();
991 ShenandoahHeapRegion* r;
992 set->clear_current_index();
993 while ((r = set->next()) != NULL) {
994 r->make_trash();
995 }
996 collection_set()->clear();
997 }
998
999 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1000 st->print_cr("Heap Regions:");
1001 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1002 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1003 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1004 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1005
1006 for (size_t i = 0; i < num_regions(); i++) {
1007 get_region(i)->print_on(st);
1008 }
1009 }
1010
1011 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1012 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1013
1014 oop humongous_obj = oop(start->bottom());
1015 size_t size = humongous_obj->size();
1016 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1017 size_t index = start->region_number() + required_regions - 1;
1018
1019 assert(!start->has_live(), "liveness must be zero");
1020
1021 for(size_t i = 0; i < required_regions; i++) {
1022 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1023 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1024 ShenandoahHeapRegion* region = get_region(index --);
1025
1026 assert(region->is_humongous(), "expect correct humongous start or continuation");
1027 assert(!region->is_cset(), "Humongous region should not be in collection set");
1028
1029 region->make_trash_immediate();
1030 }
1031 }
1032
1033 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1034 public:
1035 void do_thread(Thread* thread) {
1036 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1037 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1038 gclab->retire();
1039 }
1040 };
1041
1042 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1043 if (UseTLAB) {
1044 CollectedHeap::ensure_parsability(retire_tlabs);
1045 }
1046 ShenandoahRetireGCLABClosure cl;
1047 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1048 cl.do_thread(t);
1049 }
1050 workers()->threads_do(&cl);
1051 }
1052
1053 void ShenandoahHeap::resize_tlabs() {
1054 CollectedHeap::resize_all_tlabs();
1055 }
1056
1057 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1058 private:
1059 ShenandoahRootEvacuator* _rp;
1060
1061 public:
1062 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1063 AbstractGangTask("Shenandoah evacuate and update roots"),
1064 _rp(rp) {}
1065
1066 void work(uint worker_id) {
1067 ShenandoahParallelWorkerSession worker_session(worker_id);
1068 ShenandoahEvacOOMScope oom_evac_scope;
1069 ShenandoahEvacuateUpdateRootsClosure<> cl;
1070 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1071 _rp->roots_do(worker_id, &cl);
1072 }
1073 };
1074
1075 void ShenandoahHeap::evacuate_and_update_roots() {
1076 #if COMPILER2_OR_JVMCI
1077 DerivedPointerTable::clear();
1078 #endif
1079 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1080 {
1081 // Include concurrent roots if current cycle can not process those roots concurrently
1082 ShenandoahRootEvacuator rp(workers()->active_workers(),
1083 ShenandoahPhaseTimings::init_evac,
1084 !ShenandoahConcurrentRoots::should_do_concurrent_roots(),
1085 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1086 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1087 workers()->run_task(&roots_task);
1088 }
1089
1090 #if COMPILER2_OR_JVMCI
1091 DerivedPointerTable::update_pointers();
1092 #endif
1093 }
1094
1095 // Returns size in bytes
1096 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1097 if (ShenandoahElasticTLAB) {
1098 // With Elastic TLABs, return the max allowed size, and let the allocation path
1099 // figure out the safe size for current allocation.
1100 return ShenandoahHeapRegion::max_tlab_size_bytes();
1101 } else {
1102 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1103 }
1104 }
1105
1106 size_t ShenandoahHeap::max_tlab_size() const {
1107 // Returns size in words
1108 return ShenandoahHeapRegion::max_tlab_size_words();
1109 }
1110
1111 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1112 public:
1113 void do_thread(Thread* thread) {
1114 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1115 gclab->retire();
1116 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1117 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1118 }
1119 }
1120 };
1121
1122 void ShenandoahHeap::retire_and_reset_gclabs() {
1123 ShenandoahRetireAndResetGCLABClosure cl;
1124 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1125 cl.do_thread(t);
1126 }
1127 workers()->threads_do(&cl);
1128 }
1129
1130 void ShenandoahHeap::collect(GCCause::Cause cause) {
1131 control_thread()->request_gc(cause);
1132 }
1133
1134 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1135 //assert(false, "Shouldn't need to do full collections");
1136 }
1137
1138 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1139 Space* sp = heap_region_containing(addr);
1140 if (sp != NULL) {
1141 return sp->block_start(addr);
1142 }
1143 return NULL;
1144 }
1145
1146 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1147 Space* sp = heap_region_containing(addr);
1148 return sp->block_is_obj(addr);
1149 }
1150
1151 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const {
1152 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr);
1153 }
1154
1155 jlong ShenandoahHeap::millis_since_last_gc() {
1156 double v = heuristics()->time_since_last_gc() * 1000;
1157 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1158 return (jlong)v;
1159 }
1160
1161 void ShenandoahHeap::prepare_for_verify() {
1162 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1163 make_parsable(false);
1164 }
1165 }
1166
1167 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1168 workers()->print_worker_threads_on(st);
1169 if (ShenandoahStringDedup::is_enabled()) {
1170 ShenandoahStringDedup::print_worker_threads_on(st);
1171 }
1172 }
1173
1174 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1175 workers()->threads_do(tcl);
1176 if (_safepoint_workers != NULL) {
1177 _safepoint_workers->threads_do(tcl);
1178 }
1179 if (ShenandoahStringDedup::is_enabled()) {
1180 ShenandoahStringDedup::threads_do(tcl);
1181 }
1182 }
1183
1184 void ShenandoahHeap::print_tracing_info() const {
1185 LogTarget(Info, gc, stats) lt;
1186 if (lt.is_enabled()) {
1187 ResourceMark rm;
1188 LogStream ls(lt);
1189
1190 phase_timings()->print_on(&ls);
1191
1192 ls.cr();
1193 ls.cr();
1194
1195 shenandoah_policy()->print_gc_stats(&ls);
1196
1197 ls.cr();
1198 ls.cr();
1199
1200 if (ShenandoahPacing) {
1201 pacer()->print_on(&ls);
1202 }
1203
1204 ls.cr();
1205 ls.cr();
1206
1207 if (ShenandoahAllocationTrace) {
1208 assert(alloc_tracker() != NULL, "Must be");
1209 alloc_tracker()->print_on(&ls);
1210 } else {
1211 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1212 }
1213 }
1214 }
1215
1216 void ShenandoahHeap::verify(VerifyOption vo) {
1217 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1218 if (ShenandoahVerify) {
1219 verifier()->verify_generic(vo);
1220 } else {
1221 // TODO: Consider allocating verification bitmaps on demand,
1222 // and turn this on unconditionally.
1223 }
1224 }
1225 }
1226 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1227 return _free_set->capacity();
1228 }
1229
1230 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1231 private:
1232 MarkBitMap* _bitmap;
1233 Stack<oop,mtGC>* _oop_stack;
1234
1235 template <class T>
1236 void do_oop_work(T* p) {
1237 T o = RawAccess<>::oop_load(p);
1238 if (!CompressedOops::is_null(o)) {
1239 oop obj = CompressedOops::decode_not_null(o);
1240 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj);
1241 if (fwd == NULL) {
1242 // There is an odd interaction with VM_HeapWalkOperation, see jvmtiTagMap.cpp.
1243 //
1244 // That operation walks the reachable objects on its own, storing the marking
1245 // wavefront in the object marks. When it is done, it calls the CollectedHeap
1246 // to iterate over all objects to clean up the mess. When it reaches here,
1247 // the Shenandoah fwdptr resolution code encounters the marked objects with
1248 // NULL forwardee. Trying to act on that would crash the VM. Or fail the
1249 // asserts, should we go for resolve_forwarded_pointer(obj).
1250 //
1251 // Therefore, we have to dodge it by doing the raw access to forwardee, and
1252 // assuming the object had no forwardee, if that thing is NULL.
1253 } else {
1254 obj = fwd;
1255 }
1256 assert(oopDesc::is_oop(obj), "must be a valid oop");
1257 if (!_bitmap->is_marked(obj)) {
1258 _bitmap->mark(obj);
1259 _oop_stack->push(obj);
1260 }
1261 }
1262 }
1263 public:
1264 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1265 _bitmap(bitmap), _oop_stack(oop_stack) {}
1266 void do_oop(oop* p) { do_oop_work(p); }
1267 void do_oop(narrowOop* p) { do_oop_work(p); }
1268 };
1269
1270 /*
1271 * This is public API, used in preparation of object_iterate().
1272 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1273 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1274 * control, we call SH::make_tlabs_parsable().
1275 */
1276 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1277 // No-op.
1278 }
1279
1280 ObjectMarker* ShenandoahHeap::object_marker() {
1281 return new ShenandoahObjectMarker(this, &_aux_bit_map);
1282 }
1283
1284 bool ShenandoahHeap::commit_aux_bitmap() {
1285 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1286 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1287 return false;
1288 }
1289 return true;
1290 }
1291
1292 void ShenandoahHeap::uncommit_aux_bit_map() {
1293 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1294 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1295 }
1296 }
1297
1298 /*
1299 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1300 *
1301 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1302 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1303 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1304 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1305 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1306 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1307 * wiped the bitmap in preparation for next marking).
1308 *
1309 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1310 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1311 * is allowed to report dead objects, but is not required to do so.
1312 */
1313 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1314 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1315 if (!commit_aux_bitmap()) return;
1316
1317 // Reset bitmap
1318 _aux_bit_map.clear();
1319
1320 Stack<oop,mtGC> oop_stack;
1321
1322 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects.
1323 ShenandoahHeapIterationRootScanner rp;
1324 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1325
1326 // When concurrent root is in progress, weak roots may contain dead oops, they should not be used
1327 // for root scanning.
1328 if (is_concurrent_root_in_progress()) {
1329 rp.strong_roots_do(&oops);
1330 } else {
1331 rp.roots_do(&oops);
1332 }
1333
1334 // Work through the oop stack to traverse heap.
1335 while (! oop_stack.is_empty()) {
1336 oop obj = oop_stack.pop();
1337 assert(oopDesc::is_oop(obj), "must be a valid oop");
1338 cl->do_object(obj);
1339 obj->oop_iterate(&oops);
1340 }
1341
1342 assert(oop_stack.is_empty(), "should be empty");
1343
1344 uncommit_aux_bit_map();
1345 }
1346
1347 // Keep alive an object that was loaded with AS_NO_KEEPALIVE.
1348 void ShenandoahHeap::keep_alive(oop obj) {
1349 if (is_concurrent_mark_in_progress()) {
1350 ShenandoahBarrierSet::barrier_set()->enqueue(obj);
1351 }
1352 }
1353
1354 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1355 for (size_t i = 0; i < num_regions(); i++) {
1356 ShenandoahHeapRegion* current = get_region(i);
1357 blk->heap_region_do(current);
1358 }
1359 }
1360
1361 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1362 private:
1363 ShenandoahHeap* const _heap;
1364 ShenandoahHeapRegionClosure* const _blk;
1365
1366 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1367 volatile size_t _index;
1368 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1369
1370 public:
1371 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1372 AbstractGangTask("Parallel Region Task"),
1373 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1374
1375 void work(uint worker_id) {
1376 size_t stride = ShenandoahParallelRegionStride;
1377
1378 size_t max = _heap->num_regions();
1379 while (_index < max) {
1380 size_t cur = Atomic::fetch_and_add(&_index, stride);
1381 size_t start = cur;
1382 size_t end = MIN2(cur + stride, max);
1383 if (start >= max) break;
1384
1385 for (size_t i = cur; i < end; i++) {
1386 ShenandoahHeapRegion* current = _heap->get_region(i);
1387 _blk->heap_region_do(current);
1388 }
1389 }
1390 }
1391 };
1392
1393 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1394 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1395 if (num_regions() > ShenandoahParallelRegionStride) {
1396 ShenandoahParallelHeapRegionTask task(blk);
1397 workers()->run_task(&task);
1398 } else {
1399 heap_region_iterate(blk);
1400 }
1401 }
1402
1403 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1404 private:
1405 ShenandoahMarkingContext* const _ctx;
1406 public:
1407 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1408
1409 void heap_region_do(ShenandoahHeapRegion* r) {
1410 if (r->is_active()) {
1411 r->clear_live_data();
1412 _ctx->capture_top_at_mark_start(r);
1413 } else {
1414 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1415 assert(_ctx->top_at_mark_start(r) == r->top(),
1416 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1417 }
1418 }
1419
1420 bool is_thread_safe() { return true; }
1421 };
1422
1423 void ShenandoahHeap::op_init_mark() {
1424 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1425 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1426
1427 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1428 assert(!marking_context()->is_complete(), "should not be complete");
1429
1430 if (ShenandoahVerify) {
1431 verifier()->verify_before_concmark();
1432 }
1433
1434 if (VerifyBeforeGC) {
1435 Universe::verify();
1436 }
1437
1438 set_concurrent_mark_in_progress(true);
1439 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1440 {
1441 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1442 make_parsable(true);
1443 }
1444
1445 {
1446 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1447 ShenandoahClearLivenessClosure clc;
1448 parallel_heap_region_iterate(&clc);
1449 }
1450
1451 // Make above changes visible to worker threads
1452 OrderAccess::fence();
1453
1454 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1455
1456 if (UseTLAB) {
1457 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1458 resize_tlabs();
1459 }
1460
1461 if (ShenandoahPacing) {
1462 pacer()->setup_for_mark();
1463 }
1464 }
1465
1466 void ShenandoahHeap::op_mark() {
1467 concurrent_mark()->mark_from_roots();
1468 }
1469
1470 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1471 private:
1472 ShenandoahMarkingContext* const _ctx;
1473 public:
1474 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1475
1476 void heap_region_do(ShenandoahHeapRegion* r) {
1477 if (r->is_active()) {
1478 HeapWord *tams = _ctx->top_at_mark_start(r);
1479 HeapWord *top = r->top();
1480 if (top > tams) {
1481 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1482 }
1483 } else {
1484 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1485 assert(_ctx->top_at_mark_start(r) == r->top(),
1486 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1487 }
1488 }
1489
1490 bool is_thread_safe() { return true; }
1491 };
1492
1493 void ShenandoahHeap::op_final_mark() {
1494 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1495
1496 // It is critical that we
1497 // evacuate roots right after finishing marking, so that we don't
1498 // get unmarked objects in the roots.
1499
1500 if (!cancelled_gc()) {
1501 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1502
1503 // Marking is completed, deactivate SATB barrier
1504 set_concurrent_mark_in_progress(false);
1505 mark_complete_marking_context();
1506
1507 parallel_cleaning(false /* full gc*/);
1508
1509 if (has_forwarded_objects()) {
1510 // Degen may be caused by failed evacuation of roots
1511 if (is_degenerated_gc_in_progress()) {
1512 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
1513 } else {
1514 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::update_roots);
1515 }
1516 set_has_forwarded_objects(false);
1517 }
1518
1519 if (ShenandoahVerify) {
1520 verifier()->verify_roots_no_forwarded();
1521 }
1522 // All allocations past TAMS are implicitly live, adjust the region data.
1523 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1524 {
1525 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1526 ShenandoahCompleteLivenessClosure cl;
1527 parallel_heap_region_iterate(&cl);
1528 }
1529
1530 // Force the threads to reacquire their TLABs outside the collection set.
1531 {
1532 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs);
1533 make_parsable(true);
1534 }
1535
1536 // We are about to select the collection set, make sure it knows about
1537 // current pinning status. Also, this allows trashing more regions that
1538 // now have their pinning status dropped.
1539 {
1540 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned);
1541 sync_pinned_region_status();
1542 }
1543
1544 // Trash the collection set left over from previous cycle, if any.
1545 {
1546 ShenandoahGCPhase phase(ShenandoahPhaseTimings::trash_cset);
1547 trash_cset_regions();
1548 }
1549
1550 {
1551 ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac);
1552
1553 ShenandoahHeapLocker locker(lock());
1554 _collection_set->clear();
1555 _free_set->clear();
1556
1557 heuristics()->choose_collection_set(_collection_set);
1558
1559 _free_set->rebuild();
1560 }
1561
1562 if (!is_degenerated_gc_in_progress()) {
1563 prepare_concurrent_roots();
1564 prepare_concurrent_unloading();
1565 }
1566
1567 // If collection set has candidates, start evacuation.
1568 // Otherwise, bypass the rest of the cycle.
1569 if (!collection_set()->is_empty()) {
1570 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1571
1572 if (ShenandoahVerify) {
1573 verifier()->verify_before_evacuation();
1574 }
1575
1576 set_evacuation_in_progress(true);
1577 // From here on, we need to update references.
1578 set_has_forwarded_objects(true);
1579
1580 if (!is_degenerated_gc_in_progress()) {
1581 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1582 ShenandoahCodeRoots::arm_nmethods();
1583 }
1584 evacuate_and_update_roots();
1585 }
1586
1587 if (ShenandoahPacing) {
1588 pacer()->setup_for_evac();
1589 }
1590
1591 if (ShenandoahVerify) {
1592 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None;
1593 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1594 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots);
1595 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots);
1596 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::StringDedupRoots);
1597 }
1598
1599 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1600 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CodeRoots);
1601 }
1602 verifier()->verify_roots_no_forwarded_except(types);
1603 verifier()->verify_during_evacuation();
1604 }
1605 } else {
1606 if (ShenandoahVerify) {
1607 verifier()->verify_after_concmark();
1608 }
1609
1610 if (VerifyAfterGC) {
1611 Universe::verify();
1612 }
1613 }
1614
1615 } else {
1616 // If this cycle was updating references, we need to keep the has_forwarded_objects
1617 // flag on, for subsequent phases to deal with it.
1618 concurrent_mark()->cancel();
1619 set_concurrent_mark_in_progress(false);
1620
1621 if (process_references()) {
1622 // Abandon reference processing right away: pre-cleaning must have failed.
1623 ReferenceProcessor *rp = ref_processor();
1624 rp->disable_discovery();
1625 rp->abandon_partial_discovery();
1626 rp->verify_no_references_recorded();
1627 }
1628 }
1629 }
1630
1631 void ShenandoahHeap::op_final_evac() {
1632 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1633
1634 set_evacuation_in_progress(false);
1635
1636 {
1637 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_retire_gclabs);
1638 retire_and_reset_gclabs();
1639 }
1640
1641 if (ShenandoahVerify) {
1642 verifier()->verify_after_evacuation();
1643 }
1644
1645 if (VerifyAfterGC) {
1646 Universe::verify();
1647 }
1648 }
1649
1650 void ShenandoahHeap::op_conc_evac() {
1651 ShenandoahEvacuationTask task(this, _collection_set, true);
1652 workers()->run_task(&task);
1653 }
1654
1655 void ShenandoahHeap::op_stw_evac() {
1656 ShenandoahEvacuationTask task(this, _collection_set, false);
1657 workers()->run_task(&task);
1658 }
1659
1660 void ShenandoahHeap::op_updaterefs() {
1661 update_heap_references(true);
1662 }
1663
1664 void ShenandoahHeap::op_cleanup() {
1665 free_set()->recycle_trash();
1666 }
1667
1668 class ShenandoahConcurrentRootsEvacUpdateTask : public AbstractGangTask {
1669 private:
1670 ShenandoahVMRoots<true /*concurrent*/> _vm_roots;
1671 ShenandoahWeakRoots<true /*concurrent*/> _weak_roots;
1672 ShenandoahClassLoaderDataRoots<true /*concurrent*/, false /*single threaded*/> _cld_roots;
1673 ShenandoahConcurrentStringDedupRoots _dedup_roots;
1674 bool _include_weak_roots;
1675
1676 public:
1677 ShenandoahConcurrentRootsEvacUpdateTask(bool include_weak_roots) :
1678 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task"),
1679 _include_weak_roots(include_weak_roots) {
1680 }
1681
1682 void work(uint worker_id) {
1683 ShenandoahEvacOOMScope oom;
1684 {
1685 // vm_roots and weak_roots are OopStorage backed roots, concurrent iteration
1686 // may race against OopStorage::release() calls.
1687 ShenandoahEvacUpdateOopStorageRootsClosure cl;
1688 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1689
1690 if (_include_weak_roots) {
1691 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl);
1692 }
1693 }
1694
1695 {
1696 ShenandoahEvacuateUpdateRootsClosure<> cl;
1697 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong);
1698 _cld_roots.cld_do(&clds);
1699 }
1700
1701 {
1702 ShenandoahForwardedIsAliveClosure is_alive;
1703 ShenandoahEvacuateUpdateRootsClosure<MO_RELEASE> keep_alive;
1704 _dedup_roots.oops_do(&is_alive, &keep_alive, worker_id);
1705 }
1706 }
1707 };
1708
1709 class ShenandoahEvacUpdateCleanupOopStorageRootsClosure : public BasicOopIterateClosure {
1710 private:
1711 ShenandoahHeap* const _heap;
1712 ShenandoahMarkingContext* const _mark_context;
1713 bool _evac_in_progress;
1714 Thread* const _thread;
1715 size_t _dead_counter;
1716
1717 public:
1718 ShenandoahEvacUpdateCleanupOopStorageRootsClosure();
1719 void do_oop(oop* p);
1720 void do_oop(narrowOop* p);
1721
1722 size_t dead_counter() const;
1723 void reset_dead_counter();
1724 };
1725
1726 ShenandoahEvacUpdateCleanupOopStorageRootsClosure::ShenandoahEvacUpdateCleanupOopStorageRootsClosure() :
1727 _heap(ShenandoahHeap::heap()),
1728 _mark_context(ShenandoahHeap::heap()->marking_context()),
1729 _evac_in_progress(ShenandoahHeap::heap()->is_evacuation_in_progress()),
1730 _thread(Thread::current()),
1731 _dead_counter(0) {
1732 }
1733
1734 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(oop* p) {
1735 const oop obj = RawAccess<>::oop_load(p);
1736 if (!CompressedOops::is_null(obj)) {
1737 if (!_mark_context->is_marked(obj)) {
1738 shenandoah_assert_correct(p, obj);
1739 oop old = Atomic::cmpxchg(p, obj, oop(NULL));
1740 if (obj == old) {
1741 _dead_counter ++;
1742 }
1743 } else if (_evac_in_progress && _heap->in_collection_set(obj)) {
1744 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1745 if (resolved == obj) {
1746 resolved = _heap->evacuate_object(obj, _thread);
1747 }
1748 Atomic::cmpxchg(p, obj, resolved);
1749 assert(_heap->cancelled_gc() ||
1750 _mark_context->is_marked(resolved) && !_heap->in_collection_set(resolved),
1751 "Sanity");
1752 }
1753 }
1754 }
1755
1756 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(narrowOop* p) {
1757 ShouldNotReachHere();
1758 }
1759
1760 size_t ShenandoahEvacUpdateCleanupOopStorageRootsClosure::dead_counter() const {
1761 return _dead_counter;
1762 }
1763
1764 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::reset_dead_counter() {
1765 _dead_counter = 0;
1766 }
1767
1768 // This task not only evacuates/updates marked weak roots, but also "NULL"
1769 // dead weak roots.
1770 class ShenandoahConcurrentWeakRootsEvacUpdateTask : public AbstractGangTask {
1771 private:
1772 ShenandoahWeakRoot<true /*concurrent*/> _jni_roots;
1773 ShenandoahWeakRoot<true /*concurrent*/> _string_table_roots;
1774 ShenandoahWeakRoot<true /*concurrent*/> _resolved_method_table_roots;
1775 ShenandoahWeakRoot<true /*concurrent*/> _vm_roots;
1776
1777 public:
1778 ShenandoahConcurrentWeakRootsEvacUpdateTask() :
1779 AbstractGangTask("Shenandoah Concurrent Weak Root Task"),
1780 _jni_roots(OopStorageSet::jni_weak(), ShenandoahPhaseTimings::JNIWeakRoots),
1781 _string_table_roots(OopStorageSet::string_table_weak(), ShenandoahPhaseTimings::StringTableRoots),
1782 _resolved_method_table_roots(OopStorageSet::resolved_method_table_weak(), ShenandoahPhaseTimings::ResolvedMethodTableRoots),
1783 _vm_roots(OopStorageSet::vm_weak(), ShenandoahPhaseTimings::VMWeakRoots) {
1784 StringTable::reset_dead_counter();
1785 ResolvedMethodTable::reset_dead_counter();
1786 }
1787
1788 ~ShenandoahConcurrentWeakRootsEvacUpdateTask() {
1789 StringTable::finish_dead_counter();
1790 ResolvedMethodTable::finish_dead_counter();
1791 }
1792
1793 void work(uint worker_id) {
1794 ShenandoahEvacOOMScope oom;
1795 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration
1796 // may race against OopStorage::release() calls.
1797 ShenandoahEvacUpdateCleanupOopStorageRootsClosure cl;
1798 _jni_roots.oops_do(&cl, worker_id);
1799 _vm_roots.oops_do(&cl, worker_id);
1800
1801 cl.reset_dead_counter();
1802 _string_table_roots.oops_do(&cl, worker_id);
1803 StringTable::inc_dead_counter(cl.dead_counter());
1804
1805 cl.reset_dead_counter();
1806 _resolved_method_table_roots.oops_do(&cl, worker_id);
1807 ResolvedMethodTable::inc_dead_counter(cl.dead_counter());
1808 }
1809 };
1810
1811 void ShenandoahHeap::op_roots() {
1812 if (is_concurrent_root_in_progress()) {
1813 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
1814 // Concurrent weak root processing
1815 ShenandoahConcurrentWeakRootsEvacUpdateTask task;
1816 workers()->run_task(&task);
1817
1818 _unloader.unload();
1819 }
1820
1821 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
1822 ShenandoahConcurrentRootsEvacUpdateTask task(!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
1823 workers()->run_task(&task);
1824 }
1825 }
1826
1827 set_concurrent_root_in_progress(false);
1828 }
1829
1830 void ShenandoahHeap::op_reset() {
1831 reset_mark_bitmap();
1832 }
1833
1834 void ShenandoahHeap::op_preclean() {
1835 concurrent_mark()->preclean_weak_refs();
1836 }
1837
1838 void ShenandoahHeap::op_init_traversal() {
1839 traversal_gc()->init_traversal_collection();
1840 }
1841
1842 void ShenandoahHeap::op_traversal() {
1843 traversal_gc()->concurrent_traversal_collection();
1844 }
1845
1846 void ShenandoahHeap::op_final_traversal() {
1847 traversal_gc()->final_traversal_collection();
1848 }
1849
1850 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1851 ShenandoahMetricsSnapshot metrics;
1852 metrics.snap_before();
1853
1854 full_gc()->do_it(cause);
1855 if (UseTLAB) {
1856 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1857 resize_all_tlabs();
1858 }
1859
1860 metrics.snap_after();
1861
1862 if (metrics.is_good_progress()) {
1863 _progress_last_gc.set();
1864 } else {
1865 // Nothing to do. Tell the allocation path that we have failed to make
1866 // progress, and it can finally fail.
1867 _progress_last_gc.unset();
1868 }
1869 }
1870
1871 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1872 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1873 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1874 // some phase, we have to upgrade the Degenerate GC to Full GC.
1875
1876 clear_cancelled_gc();
1877
1878 ShenandoahMetricsSnapshot metrics;
1879 metrics.snap_before();
1880
1881 switch (point) {
1882 case _degenerated_traversal:
1883 {
1884 // Drop the collection set. Note: this leaves some already forwarded objects
1885 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1886 // workarounds in ShenandoahTraversalHeuristics.
1887
1888 ShenandoahHeapLocker locker(lock());
1889 collection_set()->clear_current_index();
1890 for (size_t i = 0; i < collection_set()->count(); i++) {
1891 ShenandoahHeapRegion* r = collection_set()->next();
1892 r->make_regular_bypass();
1893 }
1894 collection_set()->clear();
1895 }
1896 op_final_traversal();
1897 op_cleanup();
1898 return;
1899
1900 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1901 // but enters it at different points, depending on which concurrent phase had
1902 // degenerated.
1903
1904 case _degenerated_outside_cycle:
1905 // We have degenerated from outside the cycle, which means something is bad with
1906 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1907 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1908 // we can do the most aggressive degen cycle, which includes processing references and
1909 // class unloading, unless those features are explicitly disabled.
1910 //
1911 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1912 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1913 set_process_references(heuristics()->can_process_references());
1914 set_unload_classes(heuristics()->can_unload_classes());
1915
1916 if (is_traversal_mode()) {
1917 // Not possible to degenerate from here, upgrade to Full GC right away.
1918 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1919 op_degenerated_fail();
1920 return;
1921 }
1922
1923 op_reset();
1924
1925 op_init_mark();
1926 if (cancelled_gc()) {
1927 op_degenerated_fail();
1928 return;
1929 }
1930
1931 case _degenerated_mark:
1932 op_final_mark();
1933 if (cancelled_gc()) {
1934 op_degenerated_fail();
1935 return;
1936 }
1937
1938 op_cleanup();
1939
1940 case _degenerated_evac:
1941 // If heuristics thinks we should do the cycle, this flag would be set,
1942 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1943 if (is_evacuation_in_progress()) {
1944
1945 // Degeneration under oom-evac protocol might have left some objects in
1946 // collection set un-evacuated. Restart evacuation from the beginning to
1947 // capture all objects. For all the objects that are already evacuated,
1948 // it would be a simple check, which is supposed to be fast. This is also
1949 // safe to do even without degeneration, as CSet iterator is at beginning
1950 // in preparation for evacuation anyway.
1951 //
1952 // Before doing that, we need to make sure we never had any cset-pinned
1953 // regions. This may happen if allocation failure happened when evacuating
1954 // the about-to-be-pinned object, oom-evac protocol left the object in
1955 // the collection set, and then the pin reached the cset region. If we continue
1956 // the cycle here, we would trash the cset and alive objects in it. To avoid
1957 // it, we fail degeneration right away and slide into Full GC to recover.
1958
1959 {
1960 sync_pinned_region_status();
1961 collection_set()->clear_current_index();
1962
1963 ShenandoahHeapRegion* r;
1964 while ((r = collection_set()->next()) != NULL) {
1965 if (r->is_pinned()) {
1966 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1967 op_degenerated_fail();
1968 return;
1969 }
1970 }
1971
1972 collection_set()->clear_current_index();
1973 }
1974
1975 op_stw_evac();
1976 if (cancelled_gc()) {
1977 op_degenerated_fail();
1978 return;
1979 }
1980 }
1981
1982 // If heuristics thinks we should do the cycle, this flag would be set,
1983 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1984 if (has_forwarded_objects()) {
1985 op_init_updaterefs();
1986 if (cancelled_gc()) {
1987 op_degenerated_fail();
1988 return;
1989 }
1990 }
1991
1992 case _degenerated_updaterefs:
1993 if (has_forwarded_objects()) {
1994 op_final_updaterefs();
1995 if (cancelled_gc()) {
1996 op_degenerated_fail();
1997 return;
1998 }
1999 }
2000
2001 op_cleanup();
2002 break;
2003
2004 default:
2005 ShouldNotReachHere();
2006 }
2007
2008 if (ShenandoahVerify) {
2009 verifier()->verify_after_degenerated();
2010 }
2011
2012 if (VerifyAfterGC) {
2013 Universe::verify();
2014 }
2015
2016 metrics.snap_after();
2017
2018 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
2019 // because that probably means the heap is overloaded and/or fragmented.
2020 if (!metrics.is_good_progress()) {
2021 _progress_last_gc.unset();
2022 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
2023 op_degenerated_futile();
2024 } else {
2025 _progress_last_gc.set();
2026 }
2027 }
2028
2029 void ShenandoahHeap::op_degenerated_fail() {
2030 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
2031 shenandoah_policy()->record_degenerated_upgrade_to_full();
2032 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
2033 }
2034
2035 void ShenandoahHeap::op_degenerated_futile() {
2036 shenandoah_policy()->record_degenerated_upgrade_to_full();
2037 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
2038 }
2039
2040 void ShenandoahHeap::force_satb_flush_all_threads() {
2041 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
2042 // No need to flush SATBs
2043 return;
2044 }
2045
2046 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2047 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
2048 }
2049 // The threads are not "acquiring" their thread-local data, but it does not
2050 // hurt to "release" the updates here anyway.
2051 OrderAccess::fence();
2052 }
2053
2054 void ShenandoahHeap::set_gc_state_all_threads(char state) {
2055 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
2056 ShenandoahThreadLocalData::set_gc_state(t, state);
2057 }
2058 }
2059
2060 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
2061 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
2062 _gc_state.set_cond(mask, value);
2063 set_gc_state_all_threads(_gc_state.raw_value());
2064 }
2065
2066 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
2067 if (has_forwarded_objects()) {
2068 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
2069 } else {
2070 set_gc_state_mask(MARKING, in_progress);
2071 }
2072 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2073 }
2074
2075 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
2076 set_gc_state_mask(TRAVERSAL, in_progress);
2077 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
2078 }
2079
2080 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
2081 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
2082 set_gc_state_mask(EVACUATION, in_progress);
2083 }
2084
2085 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) {
2086 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?");
2087 if (in_progress) {
2088 _concurrent_root_in_progress.set();
2089 } else {
2090 _concurrent_root_in_progress.unset();
2091 }
2092 }
2093
2094 void ShenandoahHeap::ref_processing_init() {
2095 assert(_max_workers > 0, "Sanity");
2096
2097 _ref_processor =
2098 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
2099 ParallelRefProcEnabled, // MT processing
2100 _max_workers, // Degree of MT processing
2101 true, // MT discovery
2102 _max_workers, // Degree of MT discovery
2103 false, // Reference discovery is not atomic
2104 NULL, // No closure, should be installed before use
2105 true); // Scale worker threads
2106
2107 shenandoah_assert_rp_isalive_not_installed();
2108 }
2109
2110 GCTracer* ShenandoahHeap::tracer() {
2111 return shenandoah_policy()->tracer();
2112 }
2113
2114 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
2115 return _free_set->used();
2116 }
2117
2118 bool ShenandoahHeap::try_cancel_gc() {
2119 while (true) {
2120 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
2121 if (prev == CANCELLABLE) return true;
2122 else if (prev == CANCELLED) return false;
2123 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
2124 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
2125 if (Thread::current()->is_Java_thread()) {
2126 // We need to provide a safepoint here, otherwise we might
2127 // spin forever if a SP is pending.
2128 ThreadBlockInVM sp(JavaThread::current());
2129 SpinPause();
2130 }
2131 }
2132 }
2133
2134 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
2135 if (try_cancel_gc()) {
2136 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
2137 log_info(gc)("%s", msg.buffer());
2138 Events::log(Thread::current(), "%s", msg.buffer());
2139 }
2140 }
2141
2142 uint ShenandoahHeap::max_workers() {
2143 return _max_workers;
2144 }
2145
2146 void ShenandoahHeap::stop() {
2147 // The shutdown sequence should be able to terminate when GC is running.
2148
2149 // Step 0. Notify policy to disable event recording.
2150 _shenandoah_policy->record_shutdown();
2151
2152 // Step 1. Notify control thread that we are in shutdown.
2153 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
2154 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
2155 control_thread()->prepare_for_graceful_shutdown();
2156
2157 // Step 2. Notify GC workers that we are cancelling GC.
2158 cancel_gc(GCCause::_shenandoah_stop_vm);
2159
2160 // Step 3. Wait until GC worker exits normally.
2161 control_thread()->stop();
2162
2163 // Step 4. Stop String Dedup thread if it is active
2164 if (ShenandoahStringDedup::is_enabled()) {
2165 ShenandoahStringDedup::stop();
2166 }
2167 }
2168
2169 void ShenandoahHeap::stw_unload_classes(bool full_gc) {
2170 if (!unload_classes()) return;
2171 bool purged_class;
2172
2173 // Unload classes and purge SystemDictionary.
2174 {
2175 ShenandoahGCPhase phase(full_gc ?
2176 ShenandoahPhaseTimings::full_gc_purge_class_unload :
2177 ShenandoahPhaseTimings::purge_class_unload);
2178 purged_class = SystemDictionary::do_unloading(gc_timer());
2179 }
2180
2181 {
2182 ShenandoahGCPhase phase(full_gc ?
2183 ShenandoahPhaseTimings::full_gc_purge_par :
2184 ShenandoahPhaseTimings::purge_par);
2185 ShenandoahIsAliveSelector is_alive;
2186 uint num_workers = _workers->active_workers();
2187 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class);
2188 _workers->run_task(&unlink_task);
2189 }
2190
2191 {
2192 ShenandoahGCPhase phase(full_gc ?
2193 ShenandoahPhaseTimings::full_gc_purge_cldg :
2194 ShenandoahPhaseTimings::purge_cldg);
2195 ClassLoaderDataGraph::purge();
2196 }
2197 // Resize and verify metaspace
2198 MetaspaceGC::compute_new_size();
2199 MetaspaceUtils::verify_metrics();
2200 }
2201
2202 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs),
2203 // so they should not have forwarded oops.
2204 // However, we do need to "null" dead oops in the roots, if can not be done
2205 // in concurrent cycles.
2206 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) {
2207 ShenandoahGCPhase root_phase(full_gc ?
2208 ShenandoahPhaseTimings::full_gc_purge :
2209 ShenandoahPhaseTimings::purge);
2210 uint num_workers = _workers->active_workers();
2211 ShenandoahPhaseTimings::Phase timing_phase = full_gc ?
2212 ShenandoahPhaseTimings::full_gc_purge_par :
2213 ShenandoahPhaseTimings::purge_par;
2214 // Cleanup weak roots
2215 ShenandoahGCPhase phase(timing_phase);
2216 phase_timings()->record_workers_start(timing_phase);
2217 if (has_forwarded_objects()) {
2218 if (is_traversal_mode()) {
2219 ShenandoahForwardedIsAliveClosure is_alive;
2220 ShenandoahTraversalUpdateRefsClosure keep_alive;
2221 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahTraversalUpdateRefsClosure>
2222 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2223 _workers->run_task(&cleaning_task);
2224 } else {
2225 ShenandoahForwardedIsAliveClosure is_alive;
2226 ShenandoahUpdateRefsClosure keep_alive;
2227 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure>
2228 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2229 _workers->run_task(&cleaning_task);
2230 }
2231 } else {
2232 ShenandoahIsAliveClosure is_alive;
2233 #ifdef ASSERT
2234 ShenandoahAssertNotForwardedClosure verify_cl;
2235 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure>
2236 cleaning_task(&is_alive, &verify_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2237 #else
2238 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure>
2239 cleaning_task(&is_alive, &do_nothing_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading());
2240 #endif
2241 _workers->run_task(&cleaning_task);
2242 }
2243 phase_timings()->record_workers_end(timing_phase);
2244 }
2245
2246 void ShenandoahHeap::parallel_cleaning(bool full_gc) {
2247 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2248 stw_process_weak_roots(full_gc);
2249 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2250 stw_unload_classes(full_gc);
2251 }
2252 }
2253
2254 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
2255 if (is_traversal_mode()) {
2256 set_gc_state_mask(HAS_FORWARDED | UPDATEREFS, cond);
2257 } else {
2258 set_gc_state_mask(HAS_FORWARDED, cond);
2259 }
2260
2261 }
2262
2263 void ShenandoahHeap::set_process_references(bool pr) {
2264 _process_references.set_cond(pr);
2265 }
2266
2267 void ShenandoahHeap::set_unload_classes(bool uc) {
2268 _unload_classes.set_cond(uc);
2269 }
2270
2271 bool ShenandoahHeap::process_references() const {
2272 return _process_references.is_set();
2273 }
2274
2275 bool ShenandoahHeap::unload_classes() const {
2276 return _unload_classes.is_set();
2277 }
2278
2279 address ShenandoahHeap::in_cset_fast_test_addr() {
2280 ShenandoahHeap* heap = ShenandoahHeap::heap();
2281 assert(heap->collection_set() != NULL, "Sanity");
2282 return (address) heap->collection_set()->biased_map_address();
2283 }
2284
2285 address ShenandoahHeap::cancelled_gc_addr() {
2286 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2287 }
2288
2289 address ShenandoahHeap::gc_state_addr() {
2290 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2291 }
2292
2293 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2294 return Atomic::load_acquire(&_bytes_allocated_since_gc_start);
2295 }
2296
2297 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2298 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2299 }
2300
2301 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2302 _degenerated_gc_in_progress.set_cond(in_progress);
2303 }
2304
2305 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2306 _full_gc_in_progress.set_cond(in_progress);
2307 }
2308
2309 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2310 assert (is_full_gc_in_progress(), "should be");
2311 _full_gc_move_in_progress.set_cond(in_progress);
2312 }
2313
2314 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2315 set_gc_state_mask(UPDATEREFS, in_progress);
2316 }
2317
2318 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2319 ShenandoahCodeRoots::register_nmethod(nm);
2320 }
2321
2322 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2323 ShenandoahCodeRoots::unregister_nmethod(nm);
2324 }
2325
2326 void ShenandoahHeap::flush_nmethod(nmethod* nm) {
2327 ShenandoahCodeRoots::flush_nmethod(nm);
2328 }
2329
2330 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2331 heap_region_containing(o)->record_pin();
2332 return o;
2333 }
2334
2335 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2336 heap_region_containing(o)->record_unpin();
2337 }
2338
2339 void ShenandoahHeap::sync_pinned_region_status() {
2340 ShenandoahHeapLocker locker(lock());
2341
2342 for (size_t i = 0; i < num_regions(); i++) {
2343 ShenandoahHeapRegion *r = get_region(i);
2344 if (r->is_active()) {
2345 if (r->is_pinned()) {
2346 if (r->pin_count() == 0) {
2347 r->make_unpinned();
2348 }
2349 } else {
2350 if (r->pin_count() > 0) {
2351 r->make_pinned();
2352 }
2353 }
2354 }
2355 }
2356
2357 assert_pinned_region_status();
2358 }
2359
2360 #ifdef ASSERT
2361 void ShenandoahHeap::assert_pinned_region_status() {
2362 for (size_t i = 0; i < num_regions(); i++) {
2363 ShenandoahHeapRegion* r = get_region(i);
2364 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0),
2365 "Region " SIZE_FORMAT " pinning status is inconsistent", i);
2366 }
2367 }
2368 #endif
2369
2370 GCTimer* ShenandoahHeap::gc_timer() const {
2371 return _gc_timer;
2372 }
2373
2374 void ShenandoahHeap::prepare_concurrent_roots() {
2375 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2376 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) {
2377 set_concurrent_root_in_progress(true);
2378 }
2379 }
2380
2381 void ShenandoahHeap::prepare_concurrent_unloading() {
2382 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2383 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2384 _unloader.prepare();
2385 }
2386 }
2387
2388 void ShenandoahHeap::finish_concurrent_unloading() {
2389 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint");
2390 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) {
2391 _unloader.finish();
2392 }
2393 }
2394
2395 #ifdef ASSERT
2396 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2397 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2398
2399 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2400 if (UseDynamicNumberOfGCThreads ||
2401 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2402 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2403 } else {
2404 // Use ParallelGCThreads inside safepoints
2405 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2406 }
2407 } else {
2408 if (UseDynamicNumberOfGCThreads ||
2409 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2410 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2411 } else {
2412 // Use ConcGCThreads outside safepoints
2413 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2414 }
2415 }
2416 }
2417 #endif
2418
2419 ShenandoahVerifier* ShenandoahHeap::verifier() {
2420 guarantee(ShenandoahVerify, "Should be enabled");
2421 assert (_verifier != NULL, "sanity");
2422 return _verifier;
2423 }
2424
2425 template<class T>
2426 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2427 private:
2428 T cl;
2429 ShenandoahHeap* _heap;
2430 ShenandoahRegionIterator* _regions;
2431 bool _concurrent;
2432 public:
2433 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2434 AbstractGangTask("Concurrent Update References Task"),
2435 cl(T()),
2436 _heap(ShenandoahHeap::heap()),
2437 _regions(regions),
2438 _concurrent(concurrent) {
2439 }
2440
2441 void work(uint worker_id) {
2442 if (_concurrent) {
2443 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2444 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2445 do_work();
2446 } else {
2447 ShenandoahParallelWorkerSession worker_session(worker_id);
2448 do_work();
2449 }
2450 }
2451
2452 private:
2453 void do_work() {
2454 ShenandoahHeapRegion* r = _regions->next();
2455 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2456 while (r != NULL) {
2457 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2458 assert (top_at_start_ur >= r->bottom(), "sanity");
2459 if (r->is_active() && !r->is_cset()) {
2460 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2461 }
2462 if (ShenandoahPacing) {
2463 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2464 }
2465 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2466 return;
2467 }
2468 r = _regions->next();
2469 }
2470 }
2471 };
2472
2473 void ShenandoahHeap::update_heap_references(bool concurrent) {
2474 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2475 workers()->run_task(&task);
2476 }
2477
2478 void ShenandoahHeap::op_init_updaterefs() {
2479 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2480
2481 set_evacuation_in_progress(false);
2482
2483 {
2484 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs);
2485 retire_and_reset_gclabs();
2486 }
2487
2488 if (ShenandoahVerify) {
2489 if (!is_degenerated_gc_in_progress()) {
2490 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2491 }
2492 verifier()->verify_before_updaterefs();
2493 }
2494
2495 set_update_refs_in_progress(true);
2496
2497 {
2498 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare);
2499
2500 make_parsable(true);
2501 for (uint i = 0; i < num_regions(); i++) {
2502 ShenandoahHeapRegion* r = get_region(i);
2503 r->set_concurrent_iteration_safe_limit(r->top());
2504 }
2505
2506 // Reset iterator.
2507 _update_refs_iterator.reset();
2508 }
2509
2510 if (ShenandoahPacing) {
2511 pacer()->setup_for_updaterefs();
2512 }
2513 }
2514
2515 void ShenandoahHeap::op_final_updaterefs() {
2516 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2517
2518 finish_concurrent_unloading();
2519
2520 // Check if there is left-over work, and finish it
2521 if (_update_refs_iterator.has_next()) {
2522 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work);
2523
2524 // Finish updating references where we left off.
2525 clear_cancelled_gc();
2526 update_heap_references(false);
2527 }
2528
2529 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2530 // everything. On degenerated paths, cancelled gc would not be set anyway.
2531 if (cancelled_gc()) {
2532 clear_cancelled_gc();
2533 }
2534 assert(!cancelled_gc(), "Should have been done right before");
2535
2536 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) {
2537 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots);
2538 }
2539
2540 if (is_degenerated_gc_in_progress()) {
2541 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
2542 } else {
2543 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots);
2544 }
2545
2546 // Has to be done before cset is clear
2547 if (ShenandoahVerify) {
2548 verifier()->verify_roots_in_to_space();
2549 }
2550
2551 // Drop unnecessary "pinned" state from regions that does not have CP marks
2552 // anymore, as this would allow trashing them below.
2553 {
2554 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned);
2555 sync_pinned_region_status();
2556 }
2557
2558 {
2559 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset);
2560 trash_cset_regions();
2561 }
2562
2563 set_has_forwarded_objects(false);
2564 set_update_refs_in_progress(false);
2565
2566 if (ShenandoahVerify) {
2567 verifier()->verify_after_updaterefs();
2568 }
2569
2570 if (VerifyAfterGC) {
2571 Universe::verify();
2572 }
2573
2574 {
2575 ShenandoahHeapLocker locker(lock());
2576 _free_set->rebuild();
2577 }
2578 }
2579
2580 #ifdef ASSERT
2581 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2582 _lock.assert_owned_by_current_thread();
2583 }
2584
2585 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2586 _lock.assert_not_owned_by_current_thread();
2587 }
2588
2589 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2590 _lock.assert_owned_by_current_thread_or_safepoint();
2591 }
2592 #endif
2593
2594 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2595 print_on(st);
2596 print_heap_regions_on(st);
2597 }
2598
2599 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2600 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2601
2602 size_t regions_from = _bitmap_regions_per_slice * slice;
2603 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2604 for (size_t g = regions_from; g < regions_to; g++) {
2605 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2606 if (skip_self && g == r->region_number()) continue;
2607 if (get_region(g)->is_committed()) {
2608 return true;
2609 }
2610 }
2611 return false;
2612 }
2613
2614 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2615 assert_heaplock_owned_by_current_thread();
2616
2617 // Bitmaps in special regions do not need commits
2618 if (_bitmap_region_special) {
2619 return true;
2620 }
2621
2622 if (is_bitmap_slice_committed(r, true)) {
2623 // Some other region from the group is already committed, meaning the bitmap
2624 // slice is already committed, we exit right away.
2625 return true;
2626 }
2627
2628 // Commit the bitmap slice:
2629 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2630 size_t off = _bitmap_bytes_per_slice * slice;
2631 size_t len = _bitmap_bytes_per_slice;
2632 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2633 return false;
2634 }
2635 return true;
2636 }
2637
2638 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2639 assert_heaplock_owned_by_current_thread();
2640
2641 // Bitmaps in special regions do not need uncommits
2642 if (_bitmap_region_special) {
2643 return true;
2644 }
2645
2646 if (is_bitmap_slice_committed(r, true)) {
2647 // Some other region from the group is still committed, meaning the bitmap
2648 // slice is should stay committed, exit right away.
2649 return true;
2650 }
2651
2652 // Uncommit the bitmap slice:
2653 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2654 size_t off = _bitmap_bytes_per_slice * slice;
2655 size_t len = _bitmap_bytes_per_slice;
2656 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2657 return false;
2658 }
2659 return true;
2660 }
2661
2662 void ShenandoahHeap::safepoint_synchronize_begin() {
2663 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2664 SuspendibleThreadSet::synchronize();
2665 }
2666 }
2667
2668 void ShenandoahHeap::safepoint_synchronize_end() {
2669 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2670 SuspendibleThreadSet::desynchronize();
2671 }
2672 }
2673
2674 void ShenandoahHeap::vmop_entry_init_mark() {
2675 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2676 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2677 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2678
2679 try_inject_alloc_failure();
2680 VM_ShenandoahInitMark op;
2681 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2682 }
2683
2684 void ShenandoahHeap::vmop_entry_final_mark() {
2685 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2686 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2687 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2688
2689 try_inject_alloc_failure();
2690 VM_ShenandoahFinalMarkStartEvac op;
2691 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2692 }
2693
2694 void ShenandoahHeap::vmop_entry_final_evac() {
2695 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2696 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2697 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2698
2699 VM_ShenandoahFinalEvac op;
2700 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2701 }
2702
2703 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2704 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2705 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2706 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2707
2708 try_inject_alloc_failure();
2709 VM_ShenandoahInitUpdateRefs op;
2710 VMThread::execute(&op);
2711 }
2712
2713 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2714 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2715 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2716 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2717
2718 try_inject_alloc_failure();
2719 VM_ShenandoahFinalUpdateRefs op;
2720 VMThread::execute(&op);
2721 }
2722
2723 void ShenandoahHeap::vmop_entry_init_traversal() {
2724 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2725 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2726 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2727
2728 try_inject_alloc_failure();
2729 VM_ShenandoahInitTraversalGC op;
2730 VMThread::execute(&op);
2731 }
2732
2733 void ShenandoahHeap::vmop_entry_final_traversal() {
2734 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2735 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2736 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2737
2738 try_inject_alloc_failure();
2739 VM_ShenandoahFinalTraversalGC op;
2740 VMThread::execute(&op);
2741 }
2742
2743 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2744 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2745 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2746 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2747
2748 try_inject_alloc_failure();
2749 VM_ShenandoahFullGC op(cause);
2750 VMThread::execute(&op);
2751 }
2752
2753 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2754 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2755 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2756 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2757
2758 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2759 VMThread::execute(°enerated_gc);
2760 }
2761
2762 void ShenandoahHeap::entry_init_mark() {
2763 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2764 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2765 const char* msg = init_mark_event_message();
2766 GCTraceTime(Info, gc) time(msg, gc_timer());
2767 EventMark em("%s", msg);
2768
2769 ShenandoahWorkerScope scope(workers(),
2770 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2771 "init marking");
2772
2773 op_init_mark();
2774 }
2775
2776 void ShenandoahHeap::entry_final_mark() {
2777 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2778 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2779 const char* msg = final_mark_event_message();
2780 GCTraceTime(Info, gc) time(msg, gc_timer());
2781 EventMark em("%s", msg);
2782
2783 ShenandoahWorkerScope scope(workers(),
2784 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2785 "final marking");
2786
2787 op_final_mark();
2788 }
2789
2790 void ShenandoahHeap::entry_final_evac() {
2791 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2792 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2793 static const char* msg = "Pause Final Evac";
2794 GCTraceTime(Info, gc) time(msg, gc_timer());
2795 EventMark em("%s", msg);
2796
2797 op_final_evac();
2798 }
2799
2800 void ShenandoahHeap::entry_init_updaterefs() {
2801 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2802 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2803
2804 static const char* msg = "Pause Init Update Refs";
2805 GCTraceTime(Info, gc) time(msg, gc_timer());
2806 EventMark em("%s", msg);
2807
2808 // No workers used in this phase, no setup required
2809
2810 op_init_updaterefs();
2811 }
2812
2813 void ShenandoahHeap::entry_final_updaterefs() {
2814 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2815 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2816
2817 static const char* msg = "Pause Final Update Refs";
2818 GCTraceTime(Info, gc) time(msg, gc_timer());
2819 EventMark em("%s", msg);
2820
2821 ShenandoahWorkerScope scope(workers(),
2822 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2823 "final reference update");
2824
2825 op_final_updaterefs();
2826 }
2827
2828 void ShenandoahHeap::entry_init_traversal() {
2829 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2830 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2831
2832 static const char* msg = init_traversal_event_message();
2833 GCTraceTime(Info, gc) time(msg, gc_timer());
2834 EventMark em("%s", msg);
2835
2836 ShenandoahWorkerScope scope(workers(),
2837 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2838 "init traversal");
2839
2840 op_init_traversal();
2841 }
2842
2843 void ShenandoahHeap::entry_final_traversal() {
2844 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2845 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2846
2847 static const char* msg = final_traversal_event_message();
2848 GCTraceTime(Info, gc) time(msg, gc_timer());
2849 EventMark em("%s", msg);
2850
2851 ShenandoahWorkerScope scope(workers(),
2852 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2853 "final traversal");
2854
2855 op_final_traversal();
2856 }
2857
2858 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2859 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2860 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2861
2862 static const char* msg = "Pause Full";
2863 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2864 EventMark em("%s", msg);
2865
2866 ShenandoahWorkerScope scope(workers(),
2867 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2868 "full gc");
2869
2870 op_full(cause);
2871 }
2872
2873 void ShenandoahHeap::entry_degenerated(int point) {
2874 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2875 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2876
2877 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2878 const char* msg = degen_event_message(dpoint);
2879 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2880 EventMark em("%s", msg);
2881
2882 ShenandoahWorkerScope scope(workers(),
2883 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2884 "stw degenerated gc");
2885
2886 set_degenerated_gc_in_progress(true);
2887 op_degenerated(dpoint);
2888 set_degenerated_gc_in_progress(false);
2889 }
2890
2891 void ShenandoahHeap::entry_mark() {
2892 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2893
2894 const char* msg = conc_mark_event_message();
2895 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2896 EventMark em("%s", msg);
2897
2898 ShenandoahWorkerScope scope(workers(),
2899 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2900 "concurrent marking");
2901
2902 try_inject_alloc_failure();
2903 op_mark();
2904 }
2905
2906 void ShenandoahHeap::entry_evac() {
2907 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2908 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2909
2910 static const char* msg = "Concurrent evacuation";
2911 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2912 EventMark em("%s", msg);
2913
2914 ShenandoahWorkerScope scope(workers(),
2915 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2916 "concurrent evacuation");
2917
2918 try_inject_alloc_failure();
2919 op_conc_evac();
2920 }
2921
2922 void ShenandoahHeap::entry_updaterefs() {
2923 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2924
2925 static const char* msg = "Concurrent update references";
2926 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2927 EventMark em("%s", msg);
2928
2929 ShenandoahWorkerScope scope(workers(),
2930 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2931 "concurrent reference update");
2932
2933 try_inject_alloc_failure();
2934 op_updaterefs();
2935 }
2936
2937 void ShenandoahHeap::entry_roots() {
2938 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots);
2939
2940 static const char* msg = "Concurrent roots processing";
2941 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2942 EventMark em("%s", msg);
2943
2944 ShenandoahWorkerScope scope(workers(),
2945 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(),
2946 "concurrent root processing");
2947
2948 try_inject_alloc_failure();
2949 op_roots();
2950 }
2951
2952 void ShenandoahHeap::entry_cleanup() {
2953 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2954
2955 static const char* msg = "Concurrent cleanup";
2956 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2957 EventMark em("%s", msg);
2958
2959 // This phase does not use workers, no need for setup
2960
2961 try_inject_alloc_failure();
2962 op_cleanup();
2963 }
2964
2965 void ShenandoahHeap::entry_reset() {
2966 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2967
2968 static const char* msg = "Concurrent reset";
2969 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2970 EventMark em("%s", msg);
2971
2972 ShenandoahWorkerScope scope(workers(),
2973 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2974 "concurrent reset");
2975
2976 try_inject_alloc_failure();
2977 op_reset();
2978 }
2979
2980 void ShenandoahHeap::entry_preclean() {
2981 if (ShenandoahPreclean && process_references()) {
2982 static const char* msg = "Concurrent precleaning";
2983 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2984 EventMark em("%s", msg);
2985
2986 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2987
2988 ShenandoahWorkerScope scope(workers(),
2989 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2990 "concurrent preclean",
2991 /* check_workers = */ false);
2992
2993 try_inject_alloc_failure();
2994 op_preclean();
2995 }
2996 }
2997
2998 void ShenandoahHeap::entry_traversal() {
2999 static const char* msg = conc_traversal_event_message();
3000 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
3001 EventMark em("%s", msg);
3002
3003 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
3004
3005 ShenandoahWorkerScope scope(workers(),
3006 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
3007 "concurrent traversal");
3008
3009 try_inject_alloc_failure();
3010 op_traversal();
3011 }
3012
3013 void ShenandoahHeap::entry_uncommit(double shrink_before) {
3014 static const char *msg = "Concurrent uncommit";
3015 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
3016 EventMark em("%s", msg);
3017
3018 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
3019
3020 op_uncommit(shrink_before);
3021 }
3022
3023 void ShenandoahHeap::try_inject_alloc_failure() {
3024 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
3025 _inject_alloc_failure.set();
3026 os::naked_short_sleep(1);
3027 if (cancelled_gc()) {
3028 log_info(gc)("Allocation failure was successfully injected");
3029 }
3030 }
3031 }
3032
3033 bool ShenandoahHeap::should_inject_alloc_failure() {
3034 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
3035 }
3036
3037 void ShenandoahHeap::initialize_serviceability() {
3038 _memory_pool = new ShenandoahMemoryPool(this);
3039 _cycle_memory_manager.add_pool(_memory_pool);
3040 _stw_memory_manager.add_pool(_memory_pool);
3041 }
3042
3043 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
3044 GrowableArray<GCMemoryManager*> memory_managers(2);
3045 memory_managers.append(&_cycle_memory_manager);
3046 memory_managers.append(&_stw_memory_manager);
3047 return memory_managers;
3048 }
3049
3050 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
3051 GrowableArray<MemoryPool*> memory_pools(1);
3052 memory_pools.append(_memory_pool);
3053 return memory_pools;
3054 }
3055
3056 MemoryUsage ShenandoahHeap::memory_usage() {
3057 return _memory_pool->get_memory_usage();
3058 }
3059
3060 void ShenandoahHeap::enter_evacuation() {
3061 _oom_evac_handler.enter_evacuation();
3062 }
3063
3064 void ShenandoahHeap::leave_evacuation() {
3065 _oom_evac_handler.leave_evacuation();
3066 }
3067
3068 ShenandoahRegionIterator::ShenandoahRegionIterator() :
3069 _heap(ShenandoahHeap::heap()),
3070 _index(0) {}
3071
3072 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
3073 _heap(heap),
3074 _index(0) {}
3075
3076 void ShenandoahRegionIterator::reset() {
3077 _index = 0;
3078 }
3079
3080 bool ShenandoahRegionIterator::has_next() const {
3081 return _index < _heap->num_regions();
3082 }
3083
3084 char ShenandoahHeap::gc_state() const {
3085 return _gc_state.raw_value();
3086 }
3087
3088 void ShenandoahHeap::deduplicate_string(oop str) {
3089 assert(java_lang_String::is_instance(str), "invariant");
3090
3091 if (ShenandoahStringDedup::is_enabled()) {
3092 ShenandoahStringDedup::deduplicate(str);
3093 }
3094 }
3095
3096 const char* ShenandoahHeap::init_mark_event_message() const {
3097 bool update_refs = has_forwarded_objects();
3098 bool proc_refs = process_references();
3099 bool unload_cls = unload_classes();
3100
3101 if (update_refs && proc_refs && unload_cls) {
3102 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
3103 } else if (update_refs && proc_refs) {
3104 return "Pause Init Mark (update refs) (process weakrefs)";
3105 } else if (update_refs && unload_cls) {
3106 return "Pause Init Mark (update refs) (unload classes)";
3107 } else if (proc_refs && unload_cls) {
3108 return "Pause Init Mark (process weakrefs) (unload classes)";
3109 } else if (update_refs) {
3110 return "Pause Init Mark (update refs)";
3111 } else if (proc_refs) {
3112 return "Pause Init Mark (process weakrefs)";
3113 } else if (unload_cls) {
3114 return "Pause Init Mark (unload classes)";
3115 } else {
3116 return "Pause Init Mark";
3117 }
3118 }
3119
3120 const char* ShenandoahHeap::final_mark_event_message() const {
3121 bool update_refs = has_forwarded_objects();
3122 bool proc_refs = process_references();
3123 bool unload_cls = unload_classes();
3124
3125 if (update_refs && proc_refs && unload_cls) {
3126 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
3127 } else if (update_refs && proc_refs) {
3128 return "Pause Final Mark (update refs) (process weakrefs)";
3129 } else if (update_refs && unload_cls) {
3130 return "Pause Final Mark (update refs) (unload classes)";
3131 } else if (proc_refs && unload_cls) {
3132 return "Pause Final Mark (process weakrefs) (unload classes)";
3133 } else if (update_refs) {
3134 return "Pause Final Mark (update refs)";
3135 } else if (proc_refs) {
3136 return "Pause Final Mark (process weakrefs)";
3137 } else if (unload_cls) {
3138 return "Pause Final Mark (unload classes)";
3139 } else {
3140 return "Pause Final Mark";
3141 }
3142 }
3143
3144 const char* ShenandoahHeap::conc_mark_event_message() const {
3145 bool update_refs = has_forwarded_objects();
3146 bool proc_refs = process_references();
3147 bool unload_cls = unload_classes();
3148
3149 if (update_refs && proc_refs && unload_cls) {
3150 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
3151 } else if (update_refs && proc_refs) {
3152 return "Concurrent marking (update refs) (process weakrefs)";
3153 } else if (update_refs && unload_cls) {
3154 return "Concurrent marking (update refs) (unload classes)";
3155 } else if (proc_refs && unload_cls) {
3156 return "Concurrent marking (process weakrefs) (unload classes)";
3157 } else if (update_refs) {
3158 return "Concurrent marking (update refs)";
3159 } else if (proc_refs) {
3160 return "Concurrent marking (process weakrefs)";
3161 } else if (unload_cls) {
3162 return "Concurrent marking (unload classes)";
3163 } else {
3164 return "Concurrent marking";
3165 }
3166 }
3167
3168 const char* ShenandoahHeap::init_traversal_event_message() const {
3169 bool proc_refs = process_references();
3170 bool unload_cls = unload_classes();
3171
3172 if (proc_refs && unload_cls) {
3173 return "Pause Init Traversal (process weakrefs) (unload classes)";
3174 } else if (proc_refs) {
3175 return "Pause Init Traversal (process weakrefs)";
3176 } else if (unload_cls) {
3177 return "Pause Init Traversal (unload classes)";
3178 } else {
3179 return "Pause Init Traversal";
3180 }
3181 }
3182
3183 const char* ShenandoahHeap::final_traversal_event_message() const {
3184 bool proc_refs = process_references();
3185 bool unload_cls = unload_classes();
3186
3187 if (proc_refs && unload_cls) {
3188 return "Pause Final Traversal (process weakrefs) (unload classes)";
3189 } else if (proc_refs) {
3190 return "Pause Final Traversal (process weakrefs)";
3191 } else if (unload_cls) {
3192 return "Pause Final Traversal (unload classes)";
3193 } else {
3194 return "Pause Final Traversal";
3195 }
3196 }
3197
3198 const char* ShenandoahHeap::conc_traversal_event_message() const {
3199 bool proc_refs = process_references();
3200 bool unload_cls = unload_classes();
3201
3202 if (proc_refs && unload_cls) {
3203 return "Concurrent Traversal (process weakrefs) (unload classes)";
3204 } else if (proc_refs) {
3205 return "Concurrent Traversal (process weakrefs)";
3206 } else if (unload_cls) {
3207 return "Concurrent Traversal (unload classes)";
3208 } else {
3209 return "Concurrent Traversal";
3210 }
3211 }
3212
3213 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
3214 switch (point) {
3215 case _degenerated_unset:
3216 return "Pause Degenerated GC (<UNSET>)";
3217 case _degenerated_traversal:
3218 return "Pause Degenerated GC (Traversal)";
3219 case _degenerated_outside_cycle:
3220 return "Pause Degenerated GC (Outside of Cycle)";
3221 case _degenerated_mark:
3222 return "Pause Degenerated GC (Mark)";
3223 case _degenerated_evac:
3224 return "Pause Degenerated GC (Evacuation)";
3225 case _degenerated_updaterefs:
3226 return "Pause Degenerated GC (Update Refs)";
3227 default:
3228 ShouldNotReachHere();
3229 return "ERROR";
3230 }
3231 }
3232
3233 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
3234 #ifdef ASSERT
3235 assert(_liveness_cache != NULL, "sanity");
3236 assert(worker_id < _max_workers, "sanity");
3237 for (uint i = 0; i < num_regions(); i++) {
3238 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
3239 }
3240 #endif
3241 return _liveness_cache[worker_id];
3242 }
3243
3244 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
3245 assert(worker_id < _max_workers, "sanity");
3246 assert(_liveness_cache != NULL, "sanity");
3247 jushort* ld = _liveness_cache[worker_id];
3248 for (uint i = 0; i < num_regions(); i++) {
3249 ShenandoahHeapRegion* r = get_region(i);
3250 jushort live = ld[i];
3251 if (live > 0) {
3252 r->increase_live_data_gc_words(live);
3253 ld[i] = 0;
3254 }
3255 }
3256 }