1 /*
2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #include "precompiled.hpp"
25 #include "memory/allocation.hpp"
26 #include "memory/universe.hpp"
27
28 #include "gc/shared/gcArguments.hpp"
29 #include "gc/shared/gcTimer.hpp"
30 #include "gc/shared/gcTraceTime.inline.hpp"
31 #include "gc/shared/memAllocator.hpp"
32 #include "gc/shared/parallelCleaning.hpp"
33 #include "gc/shared/plab.hpp"
34
35 #include "gc/shenandoah/shenandoahAllocTracker.hpp"
36 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
37 #include "gc/shenandoah/shenandoahForwarding.hpp"
38 #include "gc/shenandoah/shenandoahClosures.inline.hpp"
39 #include "gc/shenandoah/shenandoahCollectionSet.hpp"
40 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp"
41 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp"
42 #include "gc/shenandoah/shenandoahControlThread.hpp"
43 #include "gc/shenandoah/shenandoahFreeSet.hpp"
44 #include "gc/shenandoah/shenandoahPhaseTimings.hpp"
45 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
46 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
47 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
48 #include "gc/shenandoah/shenandoahMarkCompact.hpp"
49 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
50 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
51 #include "gc/shenandoah/shenandoahMetrics.hpp"
52 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp"
53 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp"
54 #include "gc/shenandoah/shenandoahPacer.inline.hpp"
55 #include "gc/shenandoah/shenandoahRootProcessor.hpp"
56 #include "gc/shenandoah/shenandoahStringDedup.hpp"
57 #include "gc/shenandoah/shenandoahUtils.hpp"
58 #include "gc/shenandoah/shenandoahVerifier.hpp"
59 #include "gc/shenandoah/shenandoahCodeRoots.hpp"
60 #include "gc/shenandoah/shenandoahVMOperations.hpp"
61 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
62 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp"
63 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp"
64 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp"
65 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp"
66 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp"
67 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp"
68 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp"
69 #if INCLUDE_JFR
70 #include "gc/shenandoah/shenandoahJfrSupport.hpp"
71 #endif
72
73 #include "memory/metaspace.hpp"
74 #include "oops/compressedOops.inline.hpp"
75 #include "runtime/globals.hpp"
76 #include "runtime/interfaceSupport.inline.hpp"
77 #include "runtime/safepointMechanism.hpp"
78 #include "runtime/vmThread.hpp"
79 #include "services/mallocTracker.hpp"
80
81 #ifdef ASSERT
82 template <class T>
83 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) {
84 T o = RawAccess<>::oop_load(p);
85 if (! CompressedOops::is_null(o)) {
86 oop obj = CompressedOops::decode_not_null(o);
87 shenandoah_assert_not_forwarded(p, obj);
88 }
89 }
90
91 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); }
92 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); }
93 #endif
94
95 class ShenandoahPretouchHeapTask : public AbstractGangTask {
96 private:
97 ShenandoahRegionIterator _regions;
98 const size_t _page_size;
99 public:
100 ShenandoahPretouchHeapTask(size_t page_size) :
101 AbstractGangTask("Shenandoah Pretouch Heap"),
102 _page_size(page_size) {}
103
104 virtual void work(uint worker_id) {
105 ShenandoahHeapRegion* r = _regions.next();
106 while (r != NULL) {
107 os::pretouch_memory(r->bottom(), r->end(), _page_size);
108 r = _regions.next();
109 }
110 }
111 };
112
113 class ShenandoahPretouchBitmapTask : public AbstractGangTask {
114 private:
115 ShenandoahRegionIterator _regions;
116 char* _bitmap_base;
117 const size_t _bitmap_size;
118 const size_t _page_size;
119 public:
120 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) :
121 AbstractGangTask("Shenandoah Pretouch Bitmap"),
122 _bitmap_base(bitmap_base),
123 _bitmap_size(bitmap_size),
124 _page_size(page_size) {}
125
126 virtual void work(uint worker_id) {
127 ShenandoahHeapRegion* r = _regions.next();
128 while (r != NULL) {
129 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
130 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor();
131 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size);
132
133 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size);
134
135 r = _regions.next();
136 }
137 }
138 };
139
140 jint ShenandoahHeap::initialize() {
141 ShenandoahForwarding::initial_checks();
142
143 initialize_heuristics();
144
145 //
146 // Figure out heap sizing
147 //
148
149 size_t init_byte_size = InitialHeapSize;
150 size_t min_byte_size = MinHeapSize;
151 size_t max_byte_size = MaxHeapSize;
152 size_t heap_alignment = HeapAlignment;
153
154 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes();
155
156 if (ShenandoahAlwaysPreTouch) {
157 // Enabled pre-touch means the entire heap is committed right away.
158 init_byte_size = max_byte_size;
159 }
160
161 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap");
162 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap");
163
164 _num_regions = ShenandoahHeapRegion::region_count();
165
166 size_t num_committed_regions = init_byte_size / reg_size_bytes;
167 num_committed_regions = MIN2(num_committed_regions, _num_regions);
168 assert(num_committed_regions <= _num_regions, "sanity");
169 _initial_size = num_committed_regions * reg_size_bytes;
170
171 size_t num_min_regions = min_byte_size / reg_size_bytes;
172 num_min_regions = MIN2(num_min_regions, _num_regions);
173 assert(num_min_regions <= _num_regions, "sanity");
174 _minimum_size = num_min_regions * reg_size_bytes;
175
176 _committed = _initial_size;
177
178 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
179 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size();
180
181 //
182 // Reserve and commit memory for heap
183 //
184
185 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment);
186 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size()));
187 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize);
188 _heap_region_special = heap_rs.special();
189
190 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0,
191 "Misaligned heap: " PTR_FORMAT, p2i(base()));
192
193 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size);
194 if (!_heap_region_special) {
195 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false,
196 "Cannot commit heap memory");
197 }
198
199 //
200 // Reserve and commit memory for bitmap(s)
201 //
202
203 _bitmap_size = MarkBitMap::compute_size(heap_rs.size());
204 _bitmap_size = align_up(_bitmap_size, bitmap_page_size);
205
206 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor();
207
208 guarantee(bitmap_bytes_per_region != 0,
209 "Bitmap bytes per region should not be zero");
210 guarantee(is_power_of_2(bitmap_bytes_per_region),
211 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region);
212
213 if (bitmap_page_size > bitmap_bytes_per_region) {
214 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region;
215 _bitmap_bytes_per_slice = bitmap_page_size;
216 } else {
217 _bitmap_regions_per_slice = 1;
218 _bitmap_bytes_per_slice = bitmap_bytes_per_region;
219 }
220
221 guarantee(_bitmap_regions_per_slice >= 1,
222 "Should have at least one region per slice: " SIZE_FORMAT,
223 _bitmap_regions_per_slice);
224
225 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0,
226 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT,
227 _bitmap_bytes_per_slice, bitmap_page_size);
228
229 ReservedSpace bitmap(_bitmap_size, bitmap_page_size);
230 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC);
231 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize);
232 _bitmap_region_special = bitmap.special();
233
234 size_t bitmap_init_commit = _bitmap_bytes_per_slice *
235 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice;
236 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit);
237 if (!_bitmap_region_special) {
238 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false,
239 "Cannot commit bitmap memory");
240 }
241
242 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions);
243
244 if (ShenandoahVerify) {
245 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size);
246 if (!verify_bitmap.special()) {
247 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false,
248 "Cannot commit verification bitmap memory");
249 }
250 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC);
251 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize);
252 _verification_bit_map.initialize(_heap_region, verify_bitmap_region);
253 _verifier = new ShenandoahVerifier(this, &_verification_bit_map);
254 }
255
256 // Reserve aux bitmap for use in object_iterate(). We don't commit it here.
257 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size);
258 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC);
259 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize);
260 _aux_bitmap_region_special = aux_bitmap.special();
261 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region);
262
263 //
264 // Create regions and region sets
265 //
266
267 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC);
268 _free_set = new ShenandoahFreeSet(this, _num_regions);
269 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size());
270
271 {
272 ShenandoahHeapLocker locker(lock());
273
274 size_t size_words = ShenandoahHeapRegion::region_size_words();
275
276 for (size_t i = 0; i < _num_regions; i++) {
277 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i;
278 bool is_committed = i < num_committed_regions;
279 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed);
280
281 _marking_context->initialize_top_at_mark_start(r);
282 _regions[i] = r;
283 assert(!collection_set()->is_in(i), "New region should not be in collection set");
284 }
285
286 // Initialize to complete
287 _marking_context->mark_complete();
288
289 _free_set->rebuild();
290 }
291
292 if (ShenandoahAlwaysPreTouch) {
293 assert(!AlwaysPreTouch, "Should have been overridden");
294
295 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads,
296 // before initialize() below zeroes it with initializing thread. For any given region,
297 // we touch the region and the corresponding bitmaps from the same thread.
298 ShenandoahPushWorkerScope scope(workers(), _max_workers, false);
299
300 size_t pretouch_heap_page_size = heap_page_size;
301 size_t pretouch_bitmap_page_size = bitmap_page_size;
302
303 #ifdef LINUX
304 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge
305 // pages. But, the kernel needs to know that every small page is used, in order to coalesce
306 // them into huge one. Therefore, we need to pretouch with smaller pages.
307 if (UseTransparentHugePages) {
308 pretouch_heap_page_size = (size_t)os::vm_page_size();
309 pretouch_bitmap_page_size = (size_t)os::vm_page_size();
310 }
311 #endif
312
313 // OS memory managers may want to coalesce back-to-back pages. Make their jobs
314 // simpler by pre-touching continuous spaces (heap and bitmap) separately.
315
316 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
317 _num_regions, pretouch_bitmap_page_size);
318 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size);
319 _workers->run_task(&bcl);
320
321 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page",
322 _num_regions, pretouch_heap_page_size);
323 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size);
324 _workers->run_task(&hcl);
325 }
326
327 //
328 // Initialize the rest of GC subsystems
329 //
330
331 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC);
332 for (uint worker = 0; worker < _max_workers; worker++) {
333 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC);
334 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort));
335 }
336
337 // The call below uses stuff (the SATB* things) that are in G1, but probably
338 // belong into a shared location.
339 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this,
340 SATB_Q_CBL_mon,
341 20 /* G1SATBProcessCompletedThreshold */,
342 60 /* G1SATBBufferEnqueueingThresholdPercent */);
343
344 _monitoring_support = new ShenandoahMonitoringSupport(this);
345 _phase_timings = new ShenandoahPhaseTimings();
346 ShenandoahStringDedup::initialize();
347 ShenandoahCodeRoots::initialize();
348
349 if (ShenandoahAllocationTrace) {
350 _alloc_tracker = new ShenandoahAllocTracker();
351 }
352
353 if (ShenandoahPacing) {
354 _pacer = new ShenandoahPacer(this);
355 _pacer->setup_for_idle();
356 } else {
357 _pacer = NULL;
358 }
359
360 _traversal_gc = heuristics()->can_do_traversal_gc() ?
361 new ShenandoahTraversalGC(this, _num_regions) :
362 NULL;
363
364 _control_thread = new ShenandoahControlThread();
365
366 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max",
367 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size),
368 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size),
369 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity())
370 );
371
372 log_info(gc, init)("Safepointing mechanism: %s",
373 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" :
374 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown"));
375
376 return JNI_OK;
377 }
378
379 void ShenandoahHeap::initialize_heuristics() {
380 if (ShenandoahGCHeuristics != NULL) {
381 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) {
382 _heuristics = new ShenandoahAggressiveHeuristics();
383 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) {
384 _heuristics = new ShenandoahStaticHeuristics();
385 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) {
386 _heuristics = new ShenandoahAdaptiveHeuristics();
387 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) {
388 _heuristics = new ShenandoahPassiveHeuristics();
389 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) {
390 _heuristics = new ShenandoahCompactHeuristics();
391 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) {
392 _heuristics = new ShenandoahTraversalHeuristics();
393 } else {
394 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option");
395 }
396
397 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) {
398 vm_exit_during_initialization(
399 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.",
400 _heuristics->name()));
401 }
402 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) {
403 vm_exit_during_initialization(
404 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.",
405 _heuristics->name()));
406 }
407 log_info(gc, init)("Shenandoah heuristics: %s",
408 _heuristics->name());
409 } else {
410 ShouldNotReachHere();
411 }
412
413 }
414
415 #ifdef _MSC_VER
416 #pragma warning( push )
417 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
418 #endif
419
420 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) :
421 CollectedHeap(),
422 _initial_size(0),
423 _used(0),
424 _committed(0),
425 _bytes_allocated_since_gc_start(0),
426 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)),
427 _workers(NULL),
428 _safepoint_workers(NULL),
429 _heap_region_special(false),
430 _num_regions(0),
431 _regions(NULL),
432 _update_refs_iterator(this),
433 _control_thread(NULL),
434 _shenandoah_policy(policy),
435 _heuristics(NULL),
436 _free_set(NULL),
437 _scm(new ShenandoahConcurrentMark()),
438 _traversal_gc(NULL),
439 _full_gc(new ShenandoahMarkCompact()),
440 _pacer(NULL),
441 _verifier(NULL),
442 _alloc_tracker(NULL),
443 _phase_timings(NULL),
444 _monitoring_support(NULL),
445 _memory_pool(NULL),
446 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"),
447 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"),
448 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()),
449 _soft_ref_policy(),
450 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes),
451 _ref_processor(NULL),
452 _marking_context(NULL),
453 _bitmap_size(0),
454 _bitmap_regions_per_slice(0),
455 _bitmap_bytes_per_slice(0),
456 _bitmap_region_special(false),
457 _aux_bitmap_region_special(false),
458 _liveness_cache(NULL),
459 _collection_set(NULL)
460 {
461 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads);
462 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial");
463
464 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this));
465
466 _max_workers = MAX2(_max_workers, 1U);
467 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers,
468 /* are_GC_task_threads */ true,
469 /* are_ConcurrentGC_threads */ true);
470 if (_workers == NULL) {
471 vm_exit_during_initialization("Failed necessary allocation.");
472 } else {
473 _workers->initialize_workers();
474 }
475
476 if (ShenandoahParallelSafepointThreads > 1) {
477 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread",
478 ShenandoahParallelSafepointThreads,
479 /* are_GC_task_threads */ false,
480 /* are_ConcurrentGC_threads */ false);
481 _safepoint_workers->initialize_workers();
482 }
483 }
484
485 #ifdef _MSC_VER
486 #pragma warning( pop )
487 #endif
488
489 class ShenandoahResetBitmapTask : public AbstractGangTask {
490 private:
491 ShenandoahRegionIterator _regions;
492
493 public:
494 ShenandoahResetBitmapTask() :
495 AbstractGangTask("Parallel Reset Bitmap Task") {}
496
497 void work(uint worker_id) {
498 ShenandoahHeapRegion* region = _regions.next();
499 ShenandoahHeap* heap = ShenandoahHeap::heap();
500 ShenandoahMarkingContext* const ctx = heap->marking_context();
501 while (region != NULL) {
502 if (heap->is_bitmap_slice_committed(region)) {
503 ctx->clear_bitmap(region);
504 }
505 region = _regions.next();
506 }
507 }
508 };
509
510 void ShenandoahHeap::reset_mark_bitmap() {
511 assert_gc_workers(_workers->active_workers());
512 mark_incomplete_marking_context();
513
514 ShenandoahResetBitmapTask task;
515 _workers->run_task(&task);
516 }
517
518 void ShenandoahHeap::print_on(outputStream* st) const {
519 st->print_cr("Shenandoah Heap");
520 st->print_cr(" " SIZE_FORMAT "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used",
521 max_capacity() / K, committed() / K, used() / K);
522 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions",
523 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K);
524
525 st->print("Status: ");
526 if (has_forwarded_objects()) st->print("has forwarded objects, ");
527 if (is_concurrent_mark_in_progress()) st->print("marking, ");
528 if (is_evacuation_in_progress()) st->print("evacuating, ");
529 if (is_update_refs_in_progress()) st->print("updating refs, ");
530 if (is_concurrent_traversal_in_progress()) st->print("traversal, ");
531 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, ");
532 if (is_full_gc_in_progress()) st->print("full gc, ");
533 if (is_full_gc_move_in_progress()) st->print("full gc move, ");
534
535 if (cancelled_gc()) {
536 st->print("cancelled");
537 } else {
538 st->print("not cancelled");
539 }
540 st->cr();
541
542 st->print_cr("Reserved region:");
543 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ",
544 p2i(reserved_region().start()),
545 p2i(reserved_region().end()));
546
547 ShenandoahCollectionSet* cset = collection_set();
548 st->print_cr("Collection set:");
549 if (cset != NULL) {
550 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address()));
551 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address()));
552 } else {
553 st->print_cr(" (NULL)");
554 }
555
556 st->cr();
557 MetaspaceUtils::print_on(st);
558
559 if (Verbose) {
560 print_heap_regions_on(st);
561 }
562 }
563
564 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure {
565 public:
566 void do_thread(Thread* thread) {
567 assert(thread != NULL, "Sanity");
568 assert(thread->is_Worker_thread(), "Only worker thread expected");
569 ShenandoahThreadLocalData::initialize_gclab(thread);
570 }
571 };
572
573 void ShenandoahHeap::post_initialize() {
574 CollectedHeap::post_initialize();
575 MutexLocker ml(Threads_lock);
576
577 ShenandoahInitWorkerGCLABClosure init_gclabs;
578 _workers->threads_do(&init_gclabs);
579
580 // gclab can not be initialized early during VM startup, as it can not determinate its max_size.
581 // Now, we will let WorkGang to initialize gclab when new worker is created.
582 _workers->set_initialize_gclab();
583
584 _scm->initialize(_max_workers);
585 _full_gc->initialize(_gc_timer);
586
587 ref_processing_init();
588
589 _heuristics->initialize();
590
591 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers());
592 }
593
594 size_t ShenandoahHeap::used() const {
595 return OrderAccess::load_acquire(&_used);
596 }
597
598 size_t ShenandoahHeap::committed() const {
599 OrderAccess::acquire();
600 return _committed;
601 }
602
603 void ShenandoahHeap::increase_committed(size_t bytes) {
604 assert_heaplock_or_safepoint();
605 _committed += bytes;
606 }
607
608 void ShenandoahHeap::decrease_committed(size_t bytes) {
609 assert_heaplock_or_safepoint();
610 _committed -= bytes;
611 }
612
613 void ShenandoahHeap::increase_used(size_t bytes) {
614 Atomic::add(bytes, &_used);
615 }
616
617 void ShenandoahHeap::set_used(size_t bytes) {
618 OrderAccess::release_store_fence(&_used, bytes);
619 }
620
621 void ShenandoahHeap::decrease_used(size_t bytes) {
622 assert(used() >= bytes, "never decrease heap size by more than we've left");
623 Atomic::sub(bytes, &_used);
624 }
625
626 void ShenandoahHeap::increase_allocated(size_t bytes) {
627 Atomic::add(bytes, &_bytes_allocated_since_gc_start);
628 }
629
630 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) {
631 size_t bytes = words * HeapWordSize;
632 if (!waste) {
633 increase_used(bytes);
634 }
635 increase_allocated(bytes);
636 if (ShenandoahPacing) {
637 control_thread()->pacing_notify_alloc(words);
638 if (waste) {
639 pacer()->claim_for_alloc(words, true);
640 }
641 }
642 }
643
644 size_t ShenandoahHeap::capacity() const {
645 return committed();
646 }
647
648 size_t ShenandoahHeap::max_capacity() const {
649 return _num_regions * ShenandoahHeapRegion::region_size_bytes();
650 }
651
652 size_t ShenandoahHeap::min_capacity() const {
653 return _minimum_size;
654 }
655
656 size_t ShenandoahHeap::initial_capacity() const {
657 return _initial_size;
658 }
659
660 bool ShenandoahHeap::is_in(const void* p) const {
661 HeapWord* heap_base = (HeapWord*) base();
662 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions();
663 return p >= heap_base && p < last_region_end;
664 }
665
666 void ShenandoahHeap::op_uncommit(double shrink_before) {
667 assert (ShenandoahUncommit, "should be enabled");
668
669 // Application allocates from the beginning of the heap, and GC allocates at
670 // the end of it. It is more efficient to uncommit from the end, so that applications
671 // could enjoy the near committed regions. GC allocations are much less frequent,
672 // and therefore can accept the committing costs.
673
674 size_t count = 0;
675 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow
676 ShenandoahHeapRegion* r = get_region(i - 1);
677 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) {
678 ShenandoahHeapLocker locker(lock());
679 if (r->is_empty_committed()) {
680 // Do not uncommit below minimal capacity
681 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) {
682 break;
683 }
684
685 r->make_uncommitted();
686 count++;
687 }
688 }
689 SpinPause(); // allow allocators to take the lock
690 }
691
692 if (count > 0) {
693 control_thread()->notify_heap_changed();
694 }
695 }
696
697 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) {
698 // New object should fit the GCLAB size
699 size_t min_size = MAX2(size, PLAB::min_size());
700
701 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively.
702 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2;
703 new_size = MIN2(new_size, PLAB::max_size());
704 new_size = MAX2(new_size, PLAB::min_size());
705
706 // Record new heuristic value even if we take any shortcut. This captures
707 // the case when moderately-sized objects always take a shortcut. At some point,
708 // heuristics should catch up with them.
709 ShenandoahThreadLocalData::set_gclab_size(thread, new_size);
710
711 if (new_size < size) {
712 // New size still does not fit the object. Fall back to shared allocation.
713 // This avoids retiring perfectly good GCLABs, when we encounter a large object.
714 return NULL;
715 }
716
717 // Retire current GCLAB, and allocate a new one.
718 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
719 gclab->retire();
720
721 size_t actual_size = 0;
722 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size);
723 if (gclab_buf == NULL) {
724 return NULL;
725 }
726
727 assert (size <= actual_size, "allocation should fit");
728
729 if (ZeroTLAB) {
730 // ..and clear it.
731 Copy::zero_to_words(gclab_buf, actual_size);
732 } else {
733 // ...and zap just allocated object.
734 #ifdef ASSERT
735 // Skip mangling the space corresponding to the object header to
736 // ensure that the returned space is not considered parsable by
737 // any concurrent GC thread.
738 size_t hdr_size = oopDesc::header_size();
739 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal);
740 #endif // ASSERT
741 }
742 gclab->set_buf(gclab_buf, actual_size);
743 return gclab->allocate(size);
744 }
745
746 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size,
747 size_t requested_size,
748 size_t* actual_size) {
749 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size);
750 HeapWord* res = allocate_memory(req);
751 if (res != NULL) {
752 *actual_size = req.actual_size();
753 } else {
754 *actual_size = 0;
755 }
756 return res;
757 }
758
759 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size,
760 size_t word_size,
761 size_t* actual_size) {
762 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size);
763 HeapWord* res = allocate_memory(req);
764 if (res != NULL) {
765 *actual_size = req.actual_size();
766 } else {
767 *actual_size = 0;
768 }
769 return res;
770 }
771
772 ShenandoahHeap* ShenandoahHeap::heap() {
773 CollectedHeap* heap = Universe::heap();
774 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()");
775 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap");
776 return (ShenandoahHeap*) heap;
777 }
778
779 ShenandoahHeap* ShenandoahHeap::heap_no_check() {
780 CollectedHeap* heap = Universe::heap();
781 return (ShenandoahHeap*) heap;
782 }
783
784 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) {
785 ShenandoahAllocTrace trace_alloc(req.size(), req.type());
786
787 intptr_t pacer_epoch = 0;
788 bool in_new_region = false;
789 HeapWord* result = NULL;
790
791 if (req.is_mutator_alloc()) {
792 if (ShenandoahPacing) {
793 pacer()->pace_for_alloc(req.size());
794 pacer_epoch = pacer()->epoch();
795 }
796
797 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) {
798 result = allocate_memory_under_lock(req, in_new_region);
799 }
800
801 // Allocation failed, block until control thread reacted, then retry allocation.
802 //
803 // It might happen that one of the threads requesting allocation would unblock
804 // way later after GC happened, only to fail the second allocation, because
805 // other threads have already depleted the free storage. In this case, a better
806 // strategy is to try again, as long as GC makes progress.
807 //
808 // Then, we need to make sure the allocation was retried after at least one
809 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times.
810
811 size_t tries = 0;
812
813 while (result == NULL && _progress_last_gc.is_set()) {
814 tries++;
815 control_thread()->handle_alloc_failure(req.size());
816 result = allocate_memory_under_lock(req, in_new_region);
817 }
818
819 while (result == NULL && tries <= ShenandoahFullGCThreshold) {
820 tries++;
821 control_thread()->handle_alloc_failure(req.size());
822 result = allocate_memory_under_lock(req, in_new_region);
823 }
824
825 } else {
826 assert(req.is_gc_alloc(), "Can only accept GC allocs here");
827 result = allocate_memory_under_lock(req, in_new_region);
828 // Do not call handle_alloc_failure() here, because we cannot block.
829 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac().
830 }
831
832 if (in_new_region) {
833 control_thread()->notify_heap_changed();
834 }
835
836 if (result != NULL) {
837 size_t requested = req.size();
838 size_t actual = req.actual_size();
839
840 assert (req.is_lab_alloc() || (requested == actual),
841 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT,
842 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual);
843
844 if (req.is_mutator_alloc()) {
845 notify_mutator_alloc_words(actual, false);
846
847 // If we requested more than we were granted, give the rest back to pacer.
848 // This only matters if we are in the same pacing epoch: do not try to unpace
849 // over the budget for the other phase.
850 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) {
851 pacer()->unpace_for_alloc(pacer_epoch, requested - actual);
852 }
853 } else {
854 increase_used(actual*HeapWordSize);
855 }
856 }
857
858 return result;
859 }
860
861 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) {
862 ShenandoahHeapLocker locker(lock());
863 return _free_set->allocate(req, in_new_region);
864 }
865
866 class ShenandoahMemAllocator : public MemAllocator {
867 private:
868 MemAllocator& _initializer;
869 public:
870 ShenandoahMemAllocator(MemAllocator& initializer, Klass* klass, size_t word_size, Thread* thread) :
871 MemAllocator(klass, word_size + ShenandoahForwarding::word_size(), thread),
872 _initializer(initializer) {}
873
874 protected:
875 virtual HeapWord* mem_allocate(Allocation& allocation) const {
876 HeapWord* result = MemAllocator::mem_allocate(allocation);
877 // Initialize brooks-pointer
878 if (result != NULL) {
879 result += ShenandoahForwarding::word_size();
880 ShenandoahForwarding::initialize(oop(result));
881 assert(! ShenandoahHeap::heap()->in_collection_set(result), "never allocate in targetted region");
882 }
883 return result;
884 }
885
886 virtual oop initialize(HeapWord* mem) const {
887 return _initializer.initialize(mem);
888 }
889 };
890
891 oop ShenandoahHeap::obj_allocate(Klass* klass, int size, TRAPS) {
892 ObjAllocator initializer(klass, size, THREAD);
893 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
894 return allocator.allocate();
895 }
896
897 oop ShenandoahHeap::array_allocate(Klass* klass, int size, int length, bool do_zero, TRAPS) {
898 ObjArrayAllocator initializer(klass, size, length, do_zero, THREAD);
899 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
900 return allocator.allocate();
901 }
902
903 oop ShenandoahHeap::class_allocate(Klass* klass, int size, TRAPS) {
904 ClassAllocator initializer(klass, size, THREAD);
905 ShenandoahMemAllocator allocator(initializer, klass, size, THREAD);
906 return allocator.allocate();
907 }
908
909 HeapWord* ShenandoahHeap::mem_allocate(size_t size,
910 bool* gc_overhead_limit_was_exceeded) {
911 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size);
912 return allocate_memory(req);
913 }
914
915 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data,
916 size_t size,
917 Metaspace::MetadataType mdtype) {
918 MetaWord* result;
919
920 // Inform metaspace OOM to GC heuristics if class unloading is possible.
921 if (heuristics()->can_unload_classes()) {
922 ShenandoahHeuristics* h = heuristics();
923 h->record_metaspace_oom();
924 }
925
926 // Expand and retry allocation
927 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
928 if (result != NULL) {
929 return result;
930 }
931
932 // Start full GC
933 collect(GCCause::_metadata_GC_clear_soft_refs);
934
935 // Retry allocation
936 result = loader_data->metaspace_non_null()->allocate(size, mdtype);
937 if (result != NULL) {
938 return result;
939 }
940
941 // Expand and retry allocation
942 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype);
943 if (result != NULL) {
944 return result;
945 }
946
947 // Out of memory
948 return NULL;
949 }
950
951 void ShenandoahHeap::fill_with_dummy_object(HeapWord* start, HeapWord* end, bool zap) {
952 HeapWord* obj = tlab_post_allocation_setup(start);
953 CollectedHeap::fill_with_object(obj, end);
954 }
955
956 size_t ShenandoahHeap::min_dummy_object_size() const {
957 return CollectedHeap::min_dummy_object_size() + ShenandoahForwarding::word_size();
958 }
959
960 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure {
961 private:
962 ShenandoahHeap* const _heap;
963 Thread* const _thread;
964 public:
965 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) :
966 _heap(heap), _thread(Thread::current()) {}
967
968 void do_object(oop p) {
969 shenandoah_assert_marked(NULL, p);
970 if (oopDesc::equals_raw(p, ShenandoahBarrierSet::resolve_forwarded_not_null(p))) {
971 _heap->evacuate_object(p, _thread);
972 }
973 }
974 };
975
976 class ShenandoahEvacuationTask : public AbstractGangTask {
977 private:
978 ShenandoahHeap* const _sh;
979 ShenandoahCollectionSet* const _cs;
980 bool _concurrent;
981 public:
982 ShenandoahEvacuationTask(ShenandoahHeap* sh,
983 ShenandoahCollectionSet* cs,
984 bool concurrent) :
985 AbstractGangTask("Parallel Evacuation Task"),
986 _sh(sh),
987 _cs(cs),
988 _concurrent(concurrent)
989 {}
990
991 void work(uint worker_id) {
992 if (_concurrent) {
993 ShenandoahConcurrentWorkerSession worker_session(worker_id);
994 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
995 ShenandoahEvacOOMScope oom_evac_scope;
996 do_work();
997 } else {
998 ShenandoahParallelWorkerSession worker_session(worker_id);
999 ShenandoahEvacOOMScope oom_evac_scope;
1000 do_work();
1001 }
1002 }
1003
1004 private:
1005 void do_work() {
1006 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh);
1007 ShenandoahHeapRegion* r;
1008 while ((r =_cs->claim_next()) != NULL) {
1009 assert(r->has_live(), "all-garbage regions are reclaimed early");
1010 _sh->marked_object_iterate(r, &cl);
1011
1012 if (ShenandoahPacing) {
1013 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize);
1014 }
1015
1016 if (_sh->check_cancelled_gc_and_yield(_concurrent)) {
1017 break;
1018 }
1019 }
1020 }
1021 };
1022
1023 void ShenandoahHeap::trash_cset_regions() {
1024 ShenandoahHeapLocker locker(lock());
1025
1026 ShenandoahCollectionSet* set = collection_set();
1027 ShenandoahHeapRegion* r;
1028 set->clear_current_index();
1029 while ((r = set->next()) != NULL) {
1030 r->make_trash();
1031 }
1032 collection_set()->clear();
1033 }
1034
1035 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const {
1036 st->print_cr("Heap Regions:");
1037 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned");
1038 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data");
1039 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)");
1040 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)");
1041
1042 for (size_t i = 0; i < num_regions(); i++) {
1043 get_region(i)->print_on(st);
1044 }
1045 }
1046
1047 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) {
1048 assert(start->is_humongous_start(), "reclaim regions starting with the first one");
1049
1050 oop humongous_obj = oop(start->bottom() + ShenandoahForwarding::word_size());
1051 size_t size = humongous_obj->size() + ShenandoahForwarding::word_size();
1052 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize);
1053 size_t index = start->region_number() + required_regions - 1;
1054
1055 assert(!start->has_live(), "liveness must be zero");
1056
1057 for(size_t i = 0; i < required_regions; i++) {
1058 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log,
1059 // as it expects that every region belongs to a humongous region starting with a humongous start region.
1060 ShenandoahHeapRegion* region = get_region(index --);
1061
1062 assert(region->is_humongous(), "expect correct humongous start or continuation");
1063 assert(!region->is_cset(), "Humongous region should not be in collection set");
1064
1065 region->make_trash_immediate();
1066 }
1067 }
1068
1069 class ShenandoahRetireGCLABClosure : public ThreadClosure {
1070 public:
1071 void do_thread(Thread* thread) {
1072 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1073 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name());
1074 gclab->retire();
1075 }
1076 };
1077
1078 void ShenandoahHeap::make_parsable(bool retire_tlabs) {
1079 if (UseTLAB) {
1080 CollectedHeap::ensure_parsability(retire_tlabs);
1081 }
1082 ShenandoahRetireGCLABClosure cl;
1083 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1084 cl.do_thread(t);
1085 }
1086 workers()->threads_do(&cl);
1087 }
1088
1089 void ShenandoahHeap::resize_tlabs() {
1090 CollectedHeap::resize_all_tlabs();
1091 }
1092
1093 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask {
1094 private:
1095 ShenandoahRootEvacuator* _rp;
1096
1097 public:
1098 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) :
1099 AbstractGangTask("Shenandoah evacuate and update roots"),
1100 _rp(rp) {}
1101
1102 void work(uint worker_id) {
1103 ShenandoahParallelWorkerSession worker_session(worker_id);
1104 ShenandoahEvacOOMScope oom_evac_scope;
1105 ShenandoahEvacuateUpdateRootsClosure cl;
1106 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations);
1107 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id);
1108 }
1109 };
1110
1111 void ShenandoahHeap::evacuate_and_update_roots() {
1112 #if defined(COMPILER2) || INCLUDE_JVMCI
1113 DerivedPointerTable::clear();
1114 #endif
1115 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped");
1116
1117 {
1118 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac);
1119 ShenandoahEvacuateUpdateRootsTask roots_task(&rp);
1120 workers()->run_task(&roots_task);
1121 }
1122
1123 #if defined(COMPILER2) || INCLUDE_JVMCI
1124 DerivedPointerTable::update_pointers();
1125 #endif
1126 }
1127
1128 // Returns size in bytes
1129 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const {
1130 if (ShenandoahElasticTLAB) {
1131 // With Elastic TLABs, return the max allowed size, and let the allocation path
1132 // figure out the safe size for current allocation.
1133 return ShenandoahHeapRegion::max_tlab_size_bytes();
1134 } else {
1135 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes());
1136 }
1137 }
1138
1139 size_t ShenandoahHeap::max_tlab_size() const {
1140 // Returns size in words
1141 return ShenandoahHeapRegion::max_tlab_size_words();
1142 }
1143
1144 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure {
1145 public:
1146 void do_thread(Thread* thread) {
1147 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
1148 gclab->retire();
1149 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) {
1150 ShenandoahThreadLocalData::set_gclab_size(thread, 0);
1151 }
1152 }
1153 };
1154
1155 void ShenandoahHeap::retire_and_reset_gclabs() {
1156 ShenandoahRetireAndResetGCLABClosure cl;
1157 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1158 cl.do_thread(t);
1159 }
1160 workers()->threads_do(&cl);
1161 }
1162
1163 void ShenandoahHeap::collect(GCCause::Cause cause) {
1164 control_thread()->request_gc(cause);
1165 }
1166
1167 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) {
1168 //assert(false, "Shouldn't need to do full collections");
1169 }
1170
1171 HeapWord* ShenandoahHeap::block_start(const void* addr) const {
1172 Space* sp = heap_region_containing(addr);
1173 if (sp != NULL) {
1174 return sp->block_start(addr);
1175 }
1176 return NULL;
1177 }
1178
1179 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const {
1180 Space* sp = heap_region_containing(addr);
1181 return sp->block_is_obj(addr);
1182 }
1183
1184 jlong ShenandoahHeap::millis_since_last_gc() {
1185 double v = heuristics()->time_since_last_gc() * 1000;
1186 assert(0 <= v && v <= max_jlong, "value should fit: %f", v);
1187 return (jlong)v;
1188 }
1189
1190 void ShenandoahHeap::prepare_for_verify() {
1191 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) {
1192 make_parsable(false);
1193 }
1194 }
1195
1196 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const {
1197 workers()->print_worker_threads_on(st);
1198 if (ShenandoahStringDedup::is_enabled()) {
1199 ShenandoahStringDedup::print_worker_threads_on(st);
1200 }
1201 }
1202
1203 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const {
1204 workers()->threads_do(tcl);
1205 if (_safepoint_workers != NULL) {
1206 _safepoint_workers->threads_do(tcl);
1207 }
1208 if (ShenandoahStringDedup::is_enabled()) {
1209 ShenandoahStringDedup::threads_do(tcl);
1210 }
1211 }
1212
1213 void ShenandoahHeap::print_tracing_info() const {
1214 LogTarget(Info, gc, stats) lt;
1215 if (lt.is_enabled()) {
1216 ResourceMark rm;
1217 LogStream ls(lt);
1218
1219 phase_timings()->print_on(&ls);
1220
1221 ls.cr();
1222 ls.cr();
1223
1224 shenandoah_policy()->print_gc_stats(&ls);
1225
1226 ls.cr();
1227 ls.cr();
1228
1229 if (ShenandoahPacing) {
1230 pacer()->print_on(&ls);
1231 }
1232
1233 ls.cr();
1234 ls.cr();
1235
1236 if (ShenandoahAllocationTrace) {
1237 assert(alloc_tracker() != NULL, "Must be");
1238 alloc_tracker()->print_on(&ls);
1239 } else {
1240 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable.");
1241 }
1242 }
1243 }
1244
1245 void ShenandoahHeap::verify(VerifyOption vo) {
1246 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
1247 if (ShenandoahVerify) {
1248 verifier()->verify_generic(vo);
1249 } else {
1250 // TODO: Consider allocating verification bitmaps on demand,
1251 // and turn this on unconditionally.
1252 }
1253 }
1254 }
1255 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const {
1256 return _free_set->capacity();
1257 }
1258
1259 class ObjectIterateScanRootClosure : public BasicOopIterateClosure {
1260 private:
1261 MarkBitMap* _bitmap;
1262 Stack<oop,mtGC>* _oop_stack;
1263
1264 template <class T>
1265 void do_oop_work(T* p) {
1266 T o = RawAccess<>::oop_load(p);
1267 if (!CompressedOops::is_null(o)) {
1268 oop obj = CompressedOops::decode_not_null(o);
1269 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
1270 assert(oopDesc::is_oop(obj), "must be a valid oop");
1271 if (!_bitmap->is_marked((HeapWord*) obj)) {
1272 _bitmap->mark((HeapWord*) obj);
1273 _oop_stack->push(obj);
1274 }
1275 }
1276 }
1277 public:
1278 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) :
1279 _bitmap(bitmap), _oop_stack(oop_stack) {}
1280 void do_oop(oop* p) { do_oop_work(p); }
1281 void do_oop(narrowOop* p) { do_oop_work(p); }
1282 };
1283
1284 /*
1285 * This is public API, used in preparation of object_iterate().
1286 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't
1287 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can
1288 * control, we call SH::make_tlabs_parsable().
1289 */
1290 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) {
1291 // No-op.
1292 }
1293
1294 /*
1295 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping.
1296 *
1297 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear
1298 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g.
1299 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear
1300 * scanning therefore depends on having a valid marking bitmap to support it. However, we only
1301 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid
1302 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just
1303 * wiped the bitmap in preparation for next marking).
1304 *
1305 * For all those reasons, we implement object iteration as a single marking traversal, reporting
1306 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap
1307 * is allowed to report dead objects, but is not required to do so.
1308 */
1309 void ShenandoahHeap::object_iterate(ObjectClosure* cl) {
1310 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1311 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) {
1312 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration");
1313 return;
1314 }
1315
1316 // Reset bitmap
1317 _aux_bit_map.clear();
1318
1319 Stack<oop,mtGC> oop_stack;
1320
1321 // First, we process all GC roots. This populates the work stack with initial objects.
1322 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases);
1323 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack);
1324 CLDToOopClosure clds(&oops, ClassLoaderData::_claim_none);
1325 CodeBlobToOopClosure blobs(&oops, false);
1326 rp.process_all_roots(&oops, &clds, &blobs, NULL, 0);
1327
1328 // Work through the oop stack to traverse heap.
1329 while (! oop_stack.is_empty()) {
1330 oop obj = oop_stack.pop();
1331 assert(oopDesc::is_oop(obj), "must be a valid oop");
1332 cl->do_object(obj);
1333 obj->oop_iterate(&oops);
1334 }
1335
1336 assert(oop_stack.is_empty(), "should be empty");
1337
1338 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) {
1339 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration");
1340 }
1341 }
1342
1343 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) {
1344 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints");
1345 object_iterate(cl);
1346 }
1347
1348 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1349 for (size_t i = 0; i < num_regions(); i++) {
1350 ShenandoahHeapRegion* current = get_region(i);
1351 blk->heap_region_do(current);
1352 }
1353 }
1354
1355 class ShenandoahParallelHeapRegionTask : public AbstractGangTask {
1356 private:
1357 ShenandoahHeap* const _heap;
1358 ShenandoahHeapRegionClosure* const _blk;
1359
1360 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t));
1361 volatile size_t _index;
1362 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0);
1363
1364 public:
1365 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) :
1366 AbstractGangTask("Parallel Region Task"),
1367 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {}
1368
1369 void work(uint worker_id) {
1370 size_t stride = ShenandoahParallelRegionStride;
1371
1372 size_t max = _heap->num_regions();
1373 while (_index < max) {
1374 size_t cur = Atomic::add(stride, &_index) - stride;
1375 size_t start = cur;
1376 size_t end = MIN2(cur + stride, max);
1377 if (start >= max) break;
1378
1379 for (size_t i = cur; i < end; i++) {
1380 ShenandoahHeapRegion* current = _heap->get_region(i);
1381 _blk->heap_region_do(current);
1382 }
1383 }
1384 }
1385 };
1386
1387 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const {
1388 assert(blk->is_thread_safe(), "Only thread-safe closures here");
1389 if (num_regions() > ShenandoahParallelRegionStride) {
1390 ShenandoahParallelHeapRegionTask task(blk);
1391 workers()->run_task(&task);
1392 } else {
1393 heap_region_iterate(blk);
1394 }
1395 }
1396
1397 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure {
1398 private:
1399 ShenandoahMarkingContext* const _ctx;
1400 public:
1401 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {}
1402
1403 void heap_region_do(ShenandoahHeapRegion* r) {
1404 if (r->is_active()) {
1405 r->clear_live_data();
1406 _ctx->capture_top_at_mark_start(r);
1407 } else {
1408 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1409 assert(_ctx->top_at_mark_start(r) == r->top(),
1410 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number());
1411 }
1412 }
1413
1414 bool is_thread_safe() { return true; }
1415 };
1416
1417 void ShenandoahHeap::op_init_mark() {
1418 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1419 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread");
1420
1421 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap");
1422 assert(!marking_context()->is_complete(), "should not be complete");
1423
1424 if (ShenandoahVerify) {
1425 verifier()->verify_before_concmark();
1426 }
1427
1428 if (VerifyBeforeGC) {
1429 Universe::verify();
1430 }
1431
1432 set_concurrent_mark_in_progress(true);
1433 // We need to reset all TLABs because we'd lose marks on all objects allocated in them.
1434 {
1435 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable);
1436 make_parsable(true);
1437 }
1438
1439 {
1440 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness);
1441 ShenandoahClearLivenessClosure clc;
1442 parallel_heap_region_iterate(&clc);
1443 }
1444
1445 // Make above changes visible to worker threads
1446 OrderAccess::fence();
1447
1448 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots);
1449
1450 if (UseTLAB) {
1451 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs);
1452 resize_tlabs();
1453 }
1454
1455 if (ShenandoahPacing) {
1456 pacer()->setup_for_mark();
1457 }
1458 }
1459
1460 void ShenandoahHeap::op_mark() {
1461 concurrent_mark()->mark_from_roots();
1462 }
1463
1464 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure {
1465 private:
1466 ShenandoahMarkingContext* const _ctx;
1467 public:
1468 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {}
1469
1470 void heap_region_do(ShenandoahHeapRegion* r) {
1471 if (r->is_active()) {
1472 HeapWord *tams = _ctx->top_at_mark_start(r);
1473 HeapWord *top = r->top();
1474 if (top > tams) {
1475 r->increase_live_data_alloc_words(pointer_delta(top, tams));
1476 }
1477 } else {
1478 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number());
1479 assert(_ctx->top_at_mark_start(r) == r->top(),
1480 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number());
1481 }
1482 }
1483
1484 bool is_thread_safe() { return true; }
1485 };
1486
1487 void ShenandoahHeap::op_final_mark() {
1488 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1489
1490 // It is critical that we
1491 // evacuate roots right after finishing marking, so that we don't
1492 // get unmarked objects in the roots.
1493
1494 if (!cancelled_gc()) {
1495 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false);
1496
1497 // Degen may be caused by failed evacuation of roots
1498 if (is_degenerated_gc_in_progress() && has_forwarded_objects()) {
1499 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots);
1500 }
1501
1502 if (ShenandoahVerify) {
1503 verifier()->verify_roots_no_forwarded();
1504 }
1505
1506 stop_concurrent_marking();
1507
1508 {
1509 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness);
1510
1511 // All allocations past TAMS are implicitly live, adjust the region data.
1512 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
1513 ShenandoahCompleteLivenessClosure cl;
1514 parallel_heap_region_iterate(&cl);
1515 }
1516
1517 {
1518 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac);
1519
1520 make_parsable(true);
1521
1522 trash_cset_regions();
1523
1524 {
1525 ShenandoahHeapLocker locker(lock());
1526 _collection_set->clear();
1527 _free_set->clear();
1528
1529 heuristics()->choose_collection_set(_collection_set);
1530
1531 _free_set->rebuild();
1532 }
1533 }
1534
1535 // If collection set has candidates, start evacuation.
1536 // Otherwise, bypass the rest of the cycle.
1537 if (!collection_set()->is_empty()) {
1538 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac);
1539
1540 if (ShenandoahVerify) {
1541 verifier()->verify_before_evacuation();
1542 }
1543
1544 set_evacuation_in_progress(true);
1545 // From here on, we need to update references.
1546 set_has_forwarded_objects(true);
1547
1548 evacuate_and_update_roots();
1549
1550 if (ShenandoahPacing) {
1551 pacer()->setup_for_evac();
1552 }
1553
1554 if (ShenandoahVerify) {
1555 verifier()->verify_roots_no_forwarded();
1556 verifier()->verify_during_evacuation();
1557 }
1558 } else {
1559 if (ShenandoahVerify) {
1560 verifier()->verify_after_concmark();
1561 }
1562
1563 if (VerifyAfterGC) {
1564 Universe::verify();
1565 }
1566 }
1567
1568 } else {
1569 concurrent_mark()->cancel();
1570 stop_concurrent_marking();
1571
1572 if (process_references()) {
1573 // Abandon reference processing right away: pre-cleaning must have failed.
1574 ReferenceProcessor *rp = ref_processor();
1575 rp->disable_discovery();
1576 rp->abandon_partial_discovery();
1577 rp->verify_no_references_recorded();
1578 }
1579 }
1580 }
1581
1582 void ShenandoahHeap::op_final_evac() {
1583 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint");
1584
1585 set_evacuation_in_progress(false);
1586
1587 retire_and_reset_gclabs();
1588
1589 if (ShenandoahVerify) {
1590 verifier()->verify_after_evacuation();
1591 }
1592
1593 if (VerifyAfterGC) {
1594 Universe::verify();
1595 }
1596 }
1597
1598 void ShenandoahHeap::op_conc_evac() {
1599 ShenandoahEvacuationTask task(this, _collection_set, true);
1600 workers()->run_task(&task);
1601 }
1602
1603 void ShenandoahHeap::op_stw_evac() {
1604 ShenandoahEvacuationTask task(this, _collection_set, false);
1605 workers()->run_task(&task);
1606 }
1607
1608 void ShenandoahHeap::op_updaterefs() {
1609 update_heap_references(true);
1610 }
1611
1612 void ShenandoahHeap::op_cleanup() {
1613 free_set()->recycle_trash();
1614 }
1615
1616 void ShenandoahHeap::op_reset() {
1617 reset_mark_bitmap();
1618 }
1619
1620 void ShenandoahHeap::op_preclean() {
1621 concurrent_mark()->preclean_weak_refs();
1622 }
1623
1624 void ShenandoahHeap::op_init_traversal() {
1625 traversal_gc()->init_traversal_collection();
1626 }
1627
1628 void ShenandoahHeap::op_traversal() {
1629 traversal_gc()->concurrent_traversal_collection();
1630 }
1631
1632 void ShenandoahHeap::op_final_traversal() {
1633 traversal_gc()->final_traversal_collection();
1634 }
1635
1636 void ShenandoahHeap::op_full(GCCause::Cause cause) {
1637 ShenandoahMetricsSnapshot metrics;
1638 metrics.snap_before();
1639
1640 full_gc()->do_it(cause);
1641 if (UseTLAB) {
1642 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs);
1643 resize_all_tlabs();
1644 }
1645
1646 metrics.snap_after();
1647 metrics.print();
1648
1649 if (metrics.is_good_progress("Full GC")) {
1650 _progress_last_gc.set();
1651 } else {
1652 // Nothing to do. Tell the allocation path that we have failed to make
1653 // progress, and it can finally fail.
1654 _progress_last_gc.unset();
1655 }
1656 }
1657
1658 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) {
1659 // Degenerated GC is STW, but it can also fail. Current mechanics communicates
1660 // GC failure via cancelled_concgc() flag. So, if we detect the failure after
1661 // some phase, we have to upgrade the Degenerate GC to Full GC.
1662
1663 clear_cancelled_gc();
1664
1665 ShenandoahMetricsSnapshot metrics;
1666 metrics.snap_before();
1667
1668 switch (point) {
1669 case _degenerated_traversal:
1670 {
1671 // Drop the collection set. Note: this leaves some already forwarded objects
1672 // behind, which may be problematic, see comments for ShenandoahEvacAssist
1673 // workarounds in ShenandoahTraversalHeuristics.
1674
1675 ShenandoahHeapLocker locker(lock());
1676 collection_set()->clear_current_index();
1677 for (size_t i = 0; i < collection_set()->count(); i++) {
1678 ShenandoahHeapRegion* r = collection_set()->next();
1679 r->make_regular_bypass();
1680 }
1681 collection_set()->clear();
1682 }
1683 op_final_traversal();
1684 op_cleanup();
1685 return;
1686
1687 // The cases below form the Duff's-like device: it describes the actual GC cycle,
1688 // but enters it at different points, depending on which concurrent phase had
1689 // degenerated.
1690
1691 case _degenerated_outside_cycle:
1692 // We have degenerated from outside the cycle, which means something is bad with
1693 // the heap, most probably heavy humongous fragmentation, or we are very low on free
1694 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when
1695 // we can do the most aggressive degen cycle, which includes processing references and
1696 // class unloading, unless those features are explicitly disabled.
1697 //
1698 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk
1699 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover.
1700 set_process_references(heuristics()->can_process_references());
1701 set_unload_classes(heuristics()->can_unload_classes());
1702
1703 if (heuristics()->can_do_traversal_gc()) {
1704 // Not possible to degenerate from here, upgrade to Full GC right away.
1705 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1706 op_degenerated_fail();
1707 return;
1708 }
1709
1710 op_reset();
1711
1712 op_init_mark();
1713 if (cancelled_gc()) {
1714 op_degenerated_fail();
1715 return;
1716 }
1717
1718 case _degenerated_mark:
1719 op_final_mark();
1720 if (cancelled_gc()) {
1721 op_degenerated_fail();
1722 return;
1723 }
1724
1725 op_cleanup();
1726
1727 case _degenerated_evac:
1728 // If heuristics thinks we should do the cycle, this flag would be set,
1729 // and we can do evacuation. Otherwise, it would be the shortcut cycle.
1730 if (is_evacuation_in_progress()) {
1731
1732 // Degeneration under oom-evac protocol might have left some objects in
1733 // collection set un-evacuated. Restart evacuation from the beginning to
1734 // capture all objects. For all the objects that are already evacuated,
1735 // it would be a simple check, which is supposed to be fast. This is also
1736 // safe to do even without degeneration, as CSet iterator is at beginning
1737 // in preparation for evacuation anyway.
1738 collection_set()->clear_current_index();
1739
1740 op_stw_evac();
1741 if (cancelled_gc()) {
1742 op_degenerated_fail();
1743 return;
1744 }
1745 }
1746
1747 // If heuristics thinks we should do the cycle, this flag would be set,
1748 // and we need to do update-refs. Otherwise, it would be the shortcut cycle.
1749 if (has_forwarded_objects()) {
1750 op_init_updaterefs();
1751 if (cancelled_gc()) {
1752 op_degenerated_fail();
1753 return;
1754 }
1755 }
1756
1757 case _degenerated_updaterefs:
1758 if (has_forwarded_objects()) {
1759 op_final_updaterefs();
1760 if (cancelled_gc()) {
1761 op_degenerated_fail();
1762 return;
1763 }
1764 }
1765
1766 op_cleanup();
1767 break;
1768
1769 default:
1770 ShouldNotReachHere();
1771 }
1772
1773 if (ShenandoahVerify) {
1774 verifier()->verify_after_degenerated();
1775 }
1776
1777 if (VerifyAfterGC) {
1778 Universe::verify();
1779 }
1780
1781 metrics.snap_after();
1782 metrics.print();
1783
1784 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles,
1785 // because that probably means the heap is overloaded and/or fragmented.
1786 if (!metrics.is_good_progress("Degenerated GC")) {
1787 _progress_last_gc.unset();
1788 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc);
1789 op_degenerated_futile();
1790 } else {
1791 _progress_last_gc.set();
1792 }
1793 }
1794
1795 void ShenandoahHeap::op_degenerated_fail() {
1796 log_info(gc)("Cannot finish degeneration, upgrading to Full GC");
1797 shenandoah_policy()->record_degenerated_upgrade_to_full();
1798 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1799 }
1800
1801 void ShenandoahHeap::op_degenerated_futile() {
1802 shenandoah_policy()->record_degenerated_upgrade_to_full();
1803 op_full(GCCause::_shenandoah_upgrade_to_full_gc);
1804 }
1805
1806 void ShenandoahHeap::stop_concurrent_marking() {
1807 assert(is_concurrent_mark_in_progress(), "How else could we get here?");
1808 set_concurrent_mark_in_progress(false);
1809 if (!cancelled_gc()) {
1810 // If we needed to update refs, and concurrent marking has been cancelled,
1811 // we need to finish updating references.
1812 set_has_forwarded_objects(false);
1813 mark_complete_marking_context();
1814 }
1815 }
1816
1817 void ShenandoahHeap::force_satb_flush_all_threads() {
1818 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) {
1819 // No need to flush SATBs
1820 return;
1821 }
1822
1823 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1824 ShenandoahThreadLocalData::set_force_satb_flush(t, true);
1825 }
1826 // The threads are not "acquiring" their thread-local data, but it does not
1827 // hurt to "release" the updates here anyway.
1828 OrderAccess::fence();
1829 }
1830
1831 void ShenandoahHeap::set_gc_state_all_threads(char state) {
1832 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) {
1833 ShenandoahThreadLocalData::set_gc_state(t, state);
1834 }
1835 }
1836
1837 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) {
1838 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint");
1839 _gc_state.set_cond(mask, value);
1840 set_gc_state_all_threads(_gc_state.raw_value());
1841 }
1842
1843 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) {
1844 if (has_forwarded_objects()) {
1845 set_gc_state_mask(MARKING | UPDATEREFS, in_progress);
1846 } else {
1847 set_gc_state_mask(MARKING, in_progress);
1848 }
1849 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1850 }
1851
1852 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) {
1853 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED | UPDATEREFS, in_progress);
1854 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress);
1855 }
1856
1857 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) {
1858 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint");
1859 set_gc_state_mask(EVACUATION, in_progress);
1860 }
1861
1862 HeapWord* ShenandoahHeap::tlab_post_allocation_setup(HeapWord* obj) {
1863 // Initialize Brooks pointer for the next object
1864 HeapWord* result = obj + ShenandoahForwarding::word_size();
1865 ShenandoahForwarding::initialize(oop(result));
1866 return result;
1867 }
1868
1869 void ShenandoahHeap::ref_processing_init() {
1870 assert(_max_workers > 0, "Sanity");
1871
1872 _ref_processor =
1873 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery
1874 ParallelRefProcEnabled, // MT processing
1875 _max_workers, // Degree of MT processing
1876 true, // MT discovery
1877 _max_workers, // Degree of MT discovery
1878 false, // Reference discovery is not atomic
1879 NULL, // No closure, should be installed before use
1880 true); // Scale worker threads
1881
1882 shenandoah_assert_rp_isalive_not_installed();
1883 }
1884
1885 GCTracer* ShenandoahHeap::tracer() {
1886 return shenandoah_policy()->tracer();
1887 }
1888
1889 size_t ShenandoahHeap::tlab_used(Thread* thread) const {
1890 return _free_set->used();
1891 }
1892
1893 bool ShenandoahHeap::try_cancel_gc() {
1894 while (true) {
1895 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE);
1896 if (prev == CANCELLABLE) return true;
1897 else if (prev == CANCELLED) return false;
1898 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers");
1899 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED");
1900 {
1901 // We need to provide a safepoint here, otherwise we might
1902 // spin forever if a SP is pending.
1903 ThreadBlockInVM sp(JavaThread::current());
1904 SpinPause();
1905 }
1906 }
1907 }
1908
1909 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) {
1910 if (try_cancel_gc()) {
1911 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause));
1912 log_info(gc)("%s", msg.buffer());
1913 Events::log(Thread::current(), "%s", msg.buffer());
1914 }
1915 }
1916
1917 uint ShenandoahHeap::max_workers() {
1918 return _max_workers;
1919 }
1920
1921 void ShenandoahHeap::stop() {
1922 // The shutdown sequence should be able to terminate when GC is running.
1923
1924 // Step 0. Notify policy to disable event recording.
1925 _shenandoah_policy->record_shutdown();
1926
1927 // Step 1. Notify control thread that we are in shutdown.
1928 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown.
1929 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below.
1930 control_thread()->prepare_for_graceful_shutdown();
1931
1932 // Step 2. Notify GC workers that we are cancelling GC.
1933 cancel_gc(GCCause::_shenandoah_stop_vm);
1934
1935 // Step 3. Wait until GC worker exits normally.
1936 control_thread()->stop();
1937
1938 // Step 4. Stop String Dedup thread if it is active
1939 if (ShenandoahStringDedup::is_enabled()) {
1940 ShenandoahStringDedup::stop();
1941 }
1942 }
1943
1944 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) {
1945 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled");
1946
1947 ShenandoahGCPhase root_phase(full_gc ?
1948 ShenandoahPhaseTimings::full_gc_purge :
1949 ShenandoahPhaseTimings::purge);
1950
1951 ShenandoahIsAliveSelector alive;
1952 BoolObjectClosure* is_alive = alive.is_alive_closure();
1953
1954 bool purged_class;
1955
1956 // Unload classes and purge SystemDictionary.
1957 {
1958 ShenandoahGCPhase phase(full_gc ?
1959 ShenandoahPhaseTimings::full_gc_purge_class_unload :
1960 ShenandoahPhaseTimings::purge_class_unload);
1961 purged_class = SystemDictionary::do_unloading(gc_timer());
1962 }
1963
1964 {
1965 ShenandoahGCPhase phase(full_gc ?
1966 ShenandoahPhaseTimings::full_gc_purge_par :
1967 ShenandoahPhaseTimings::purge_par);
1968 uint active = _workers->active_workers();
1969 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true);
1970 _workers->run_task(&unlink_task);
1971 }
1972
1973 {
1974 ShenandoahGCPhase phase(full_gc ?
1975 ShenandoahPhaseTimings::full_gc_purge_cldg :
1976 ShenandoahPhaseTimings::purge_cldg);
1977 ClassLoaderDataGraph::purge();
1978 }
1979 }
1980
1981 void ShenandoahHeap::set_has_forwarded_objects(bool cond) {
1982 set_gc_state_mask(HAS_FORWARDED, cond);
1983 }
1984
1985 void ShenandoahHeap::set_process_references(bool pr) {
1986 _process_references.set_cond(pr);
1987 }
1988
1989 void ShenandoahHeap::set_unload_classes(bool uc) {
1990 _unload_classes.set_cond(uc);
1991 }
1992
1993 bool ShenandoahHeap::process_references() const {
1994 return _process_references.is_set();
1995 }
1996
1997 bool ShenandoahHeap::unload_classes() const {
1998 return _unload_classes.is_set();
1999 }
2000
2001 address ShenandoahHeap::in_cset_fast_test_addr() {
2002 ShenandoahHeap* heap = ShenandoahHeap::heap();
2003 assert(heap->collection_set() != NULL, "Sanity");
2004 return (address) heap->collection_set()->biased_map_address();
2005 }
2006
2007 address ShenandoahHeap::cancelled_gc_addr() {
2008 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of();
2009 }
2010
2011 address ShenandoahHeap::gc_state_addr() {
2012 return (address) ShenandoahHeap::heap()->_gc_state.addr_of();
2013 }
2014
2015 size_t ShenandoahHeap::bytes_allocated_since_gc_start() {
2016 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start);
2017 }
2018
2019 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() {
2020 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0);
2021 }
2022
2023 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) {
2024 _degenerated_gc_in_progress.set_cond(in_progress);
2025 }
2026
2027 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) {
2028 _full_gc_in_progress.set_cond(in_progress);
2029 }
2030
2031 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) {
2032 assert (is_full_gc_in_progress(), "should be");
2033 _full_gc_move_in_progress.set_cond(in_progress);
2034 }
2035
2036 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) {
2037 set_gc_state_mask(UPDATEREFS, in_progress);
2038 }
2039
2040 void ShenandoahHeap::register_nmethod(nmethod* nm) {
2041 ShenandoahCodeRoots::add_nmethod(nm);
2042 }
2043
2044 void ShenandoahHeap::unregister_nmethod(nmethod* nm) {
2045 ShenandoahCodeRoots::remove_nmethod(nm);
2046 }
2047
2048 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) {
2049 ShenandoahHeapLocker locker(lock());
2050 heap_region_containing(o)->make_pinned();
2051 return o;
2052 }
2053
2054 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) {
2055 ShenandoahHeapLocker locker(lock());
2056 heap_region_containing(o)->make_unpinned();
2057 }
2058
2059 GCTimer* ShenandoahHeap::gc_timer() const {
2060 return _gc_timer;
2061 }
2062
2063 #ifdef ASSERT
2064 void ShenandoahHeap::assert_gc_workers(uint nworkers) {
2065 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity");
2066
2067 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) {
2068 if (UseDynamicNumberOfGCThreads ||
2069 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) {
2070 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has");
2071 } else {
2072 // Use ParallelGCThreads inside safepoints
2073 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints");
2074 }
2075 } else {
2076 if (UseDynamicNumberOfGCThreads ||
2077 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) {
2078 assert(nworkers <= ConcGCThreads, "Cannot use more than it has");
2079 } else {
2080 // Use ConcGCThreads outside safepoints
2081 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints");
2082 }
2083 }
2084 }
2085 #endif
2086
2087 ShenandoahVerifier* ShenandoahHeap::verifier() {
2088 guarantee(ShenandoahVerify, "Should be enabled");
2089 assert (_verifier != NULL, "sanity");
2090 return _verifier;
2091 }
2092
2093 template<class T>
2094 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask {
2095 private:
2096 T cl;
2097 ShenandoahHeap* _heap;
2098 ShenandoahRegionIterator* _regions;
2099 bool _concurrent;
2100 public:
2101 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) :
2102 AbstractGangTask("Concurrent Update References Task"),
2103 cl(T()),
2104 _heap(ShenandoahHeap::heap()),
2105 _regions(regions),
2106 _concurrent(concurrent) {
2107 }
2108
2109 void work(uint worker_id) {
2110 if (_concurrent) {
2111 ShenandoahConcurrentWorkerSession worker_session(worker_id);
2112 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers);
2113 do_work();
2114 } else {
2115 ShenandoahParallelWorkerSession worker_session(worker_id);
2116 do_work();
2117 }
2118 }
2119
2120 private:
2121 void do_work() {
2122 ShenandoahHeapRegion* r = _regions->next();
2123 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context();
2124 while (r != NULL) {
2125 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit();
2126 assert (top_at_start_ur >= r->bottom(), "sanity");
2127 if (r->is_active() && !r->is_cset()) {
2128 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur);
2129 }
2130 if (ShenandoahPacing) {
2131 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom()));
2132 }
2133 if (_heap->check_cancelled_gc_and_yield(_concurrent)) {
2134 return;
2135 }
2136 r = _regions->next();
2137 }
2138 }
2139 };
2140
2141 void ShenandoahHeap::update_heap_references(bool concurrent) {
2142 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent);
2143 workers()->run_task(&task);
2144 }
2145
2146 void ShenandoahHeap::op_init_updaterefs() {
2147 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2148
2149 set_evacuation_in_progress(false);
2150
2151 retire_and_reset_gclabs();
2152
2153 if (ShenandoahVerify) {
2154 verifier()->verify_before_updaterefs();
2155 }
2156
2157 set_update_refs_in_progress(true);
2158 make_parsable(true);
2159 for (uint i = 0; i < num_regions(); i++) {
2160 ShenandoahHeapRegion* r = get_region(i);
2161 r->set_concurrent_iteration_safe_limit(r->top());
2162 }
2163
2164 // Reset iterator.
2165 _update_refs_iterator.reset();
2166
2167 if (ShenandoahPacing) {
2168 pacer()->setup_for_updaterefs();
2169 }
2170 }
2171
2172 void ShenandoahHeap::op_final_updaterefs() {
2173 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint");
2174
2175 // Check if there is left-over work, and finish it
2176 if (_update_refs_iterator.has_next()) {
2177 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work);
2178
2179 // Finish updating references where we left off.
2180 clear_cancelled_gc();
2181 update_heap_references(false);
2182 }
2183
2184 // Clear cancelled GC, if set. On cancellation path, the block before would handle
2185 // everything. On degenerated paths, cancelled gc would not be set anyway.
2186 if (cancelled_gc()) {
2187 clear_cancelled_gc();
2188 }
2189 assert(!cancelled_gc(), "Should have been done right before");
2190
2191 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ?
2192 ShenandoahPhaseTimings::degen_gc_update_roots:
2193 ShenandoahPhaseTimings::final_update_refs_roots);
2194
2195 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle);
2196
2197 trash_cset_regions();
2198 set_has_forwarded_objects(false);
2199 set_update_refs_in_progress(false);
2200
2201 if (ShenandoahVerify) {
2202 verifier()->verify_roots_no_forwarded();
2203 verifier()->verify_after_updaterefs();
2204 }
2205
2206 if (VerifyAfterGC) {
2207 Universe::verify();
2208 }
2209
2210 {
2211 ShenandoahHeapLocker locker(lock());
2212 _free_set->rebuild();
2213 }
2214 }
2215
2216 #ifdef ASSERT
2217 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() {
2218 _lock.assert_owned_by_current_thread();
2219 }
2220
2221 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() {
2222 _lock.assert_not_owned_by_current_thread();
2223 }
2224
2225 void ShenandoahHeap::assert_heaplock_or_safepoint() {
2226 _lock.assert_owned_by_current_thread_or_safepoint();
2227 }
2228 #endif
2229
2230 void ShenandoahHeap::print_extended_on(outputStream *st) const {
2231 print_on(st);
2232 print_heap_regions_on(st);
2233 }
2234
2235 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) {
2236 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2237
2238 size_t regions_from = _bitmap_regions_per_slice * slice;
2239 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1));
2240 for (size_t g = regions_from; g < regions_to; g++) {
2241 assert (g / _bitmap_regions_per_slice == slice, "same slice");
2242 if (skip_self && g == r->region_number()) continue;
2243 if (get_region(g)->is_committed()) {
2244 return true;
2245 }
2246 }
2247 return false;
2248 }
2249
2250 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) {
2251 assert_heaplock_owned_by_current_thread();
2252
2253 // Bitmaps in special regions do not need commits
2254 if (_bitmap_region_special) {
2255 return true;
2256 }
2257
2258 if (is_bitmap_slice_committed(r, true)) {
2259 // Some other region from the group is already committed, meaning the bitmap
2260 // slice is already committed, we exit right away.
2261 return true;
2262 }
2263
2264 // Commit the bitmap slice:
2265 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2266 size_t off = _bitmap_bytes_per_slice * slice;
2267 size_t len = _bitmap_bytes_per_slice;
2268 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) {
2269 return false;
2270 }
2271 return true;
2272 }
2273
2274 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) {
2275 assert_heaplock_owned_by_current_thread();
2276
2277 // Bitmaps in special regions do not need uncommits
2278 if (_bitmap_region_special) {
2279 return true;
2280 }
2281
2282 if (is_bitmap_slice_committed(r, true)) {
2283 // Some other region from the group is still committed, meaning the bitmap
2284 // slice is should stay committed, exit right away.
2285 return true;
2286 }
2287
2288 // Uncommit the bitmap slice:
2289 size_t slice = r->region_number() / _bitmap_regions_per_slice;
2290 size_t off = _bitmap_bytes_per_slice * slice;
2291 size_t len = _bitmap_bytes_per_slice;
2292 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) {
2293 return false;
2294 }
2295 return true;
2296 }
2297
2298 void ShenandoahHeap::safepoint_synchronize_begin() {
2299 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2300 SuspendibleThreadSet::synchronize();
2301 }
2302 }
2303
2304 void ShenandoahHeap::safepoint_synchronize_end() {
2305 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) {
2306 SuspendibleThreadSet::desynchronize();
2307 }
2308 }
2309
2310 void ShenandoahHeap::vmop_entry_init_mark() {
2311 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2312 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2313 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross);
2314
2315 try_inject_alloc_failure();
2316 VM_ShenandoahInitMark op;
2317 VMThread::execute(&op); // jump to entry_init_mark() under safepoint
2318 }
2319
2320 void ShenandoahHeap::vmop_entry_final_mark() {
2321 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2322 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2323 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross);
2324
2325 try_inject_alloc_failure();
2326 VM_ShenandoahFinalMarkStartEvac op;
2327 VMThread::execute(&op); // jump to entry_final_mark under safepoint
2328 }
2329
2330 void ShenandoahHeap::vmop_entry_final_evac() {
2331 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2332 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2333 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross);
2334
2335 VM_ShenandoahFinalEvac op;
2336 VMThread::execute(&op); // jump to entry_final_evac under safepoint
2337 }
2338
2339 void ShenandoahHeap::vmop_entry_init_updaterefs() {
2340 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2341 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2342 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross);
2343
2344 try_inject_alloc_failure();
2345 VM_ShenandoahInitUpdateRefs op;
2346 VMThread::execute(&op);
2347 }
2348
2349 void ShenandoahHeap::vmop_entry_final_updaterefs() {
2350 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2351 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2352 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross);
2353
2354 try_inject_alloc_failure();
2355 VM_ShenandoahFinalUpdateRefs op;
2356 VMThread::execute(&op);
2357 }
2358
2359 void ShenandoahHeap::vmop_entry_init_traversal() {
2360 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2361 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2362 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross);
2363
2364 try_inject_alloc_failure();
2365 VM_ShenandoahInitTraversalGC op;
2366 VMThread::execute(&op);
2367 }
2368
2369 void ShenandoahHeap::vmop_entry_final_traversal() {
2370 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters());
2371 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2372 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross);
2373
2374 try_inject_alloc_failure();
2375 VM_ShenandoahFinalTraversalGC op;
2376 VMThread::execute(&op);
2377 }
2378
2379 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) {
2380 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2381 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2382 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross);
2383
2384 try_inject_alloc_failure();
2385 VM_ShenandoahFullGC op(cause);
2386 VMThread::execute(&op);
2387 }
2388
2389 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) {
2390 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters());
2391 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross);
2392 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross);
2393
2394 VM_ShenandoahDegeneratedGC degenerated_gc((int)point);
2395 VMThread::execute(°enerated_gc);
2396 }
2397
2398 void ShenandoahHeap::entry_init_mark() {
2399 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2400 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark);
2401 const char* msg = init_mark_event_message();
2402 GCTraceTime(Info, gc) time(msg, gc_timer());
2403 EventMark em("%s", msg);
2404
2405 ShenandoahWorkerScope scope(workers(),
2406 ShenandoahWorkerPolicy::calc_workers_for_init_marking(),
2407 "init marking");
2408
2409 op_init_mark();
2410 }
2411
2412 void ShenandoahHeap::entry_final_mark() {
2413 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2414 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark);
2415 const char* msg = final_mark_event_message();
2416 GCTraceTime(Info, gc) time(msg, gc_timer());
2417 EventMark em("%s", msg);
2418
2419 ShenandoahWorkerScope scope(workers(),
2420 ShenandoahWorkerPolicy::calc_workers_for_final_marking(),
2421 "final marking");
2422
2423 op_final_mark();
2424 }
2425
2426 void ShenandoahHeap::entry_final_evac() {
2427 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2428 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac);
2429 static const char* msg = "Pause Final Evac";
2430 GCTraceTime(Info, gc) time(msg, gc_timer());
2431 EventMark em("%s", msg);
2432
2433 op_final_evac();
2434 }
2435
2436 void ShenandoahHeap::entry_init_updaterefs() {
2437 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2438 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs);
2439
2440 static const char* msg = "Pause Init Update Refs";
2441 GCTraceTime(Info, gc) time(msg, gc_timer());
2442 EventMark em("%s", msg);
2443
2444 // No workers used in this phase, no setup required
2445
2446 op_init_updaterefs();
2447 }
2448
2449 void ShenandoahHeap::entry_final_updaterefs() {
2450 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2451 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs);
2452
2453 static const char* msg = "Pause Final Update Refs";
2454 GCTraceTime(Info, gc) time(msg, gc_timer());
2455 EventMark em("%s", msg);
2456
2457 ShenandoahWorkerScope scope(workers(),
2458 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(),
2459 "final reference update");
2460
2461 op_final_updaterefs();
2462 }
2463
2464 void ShenandoahHeap::entry_init_traversal() {
2465 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2466 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc);
2467
2468 static const char* msg = "Pause Init Traversal";
2469 GCTraceTime(Info, gc) time(msg, gc_timer());
2470 EventMark em("%s", msg);
2471
2472 ShenandoahWorkerScope scope(workers(),
2473 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2474 "init traversal");
2475
2476 op_init_traversal();
2477 }
2478
2479 void ShenandoahHeap::entry_final_traversal() {
2480 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2481 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc);
2482
2483 static const char* msg = "Pause Final Traversal";
2484 GCTraceTime(Info, gc) time(msg, gc_timer());
2485 EventMark em("%s", msg);
2486
2487 ShenandoahWorkerScope scope(workers(),
2488 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(),
2489 "final traversal");
2490
2491 op_final_traversal();
2492 }
2493
2494 void ShenandoahHeap::entry_full(GCCause::Cause cause) {
2495 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2496 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc);
2497
2498 static const char* msg = "Pause Full";
2499 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true);
2500 EventMark em("%s", msg);
2501
2502 ShenandoahWorkerScope scope(workers(),
2503 ShenandoahWorkerPolicy::calc_workers_for_fullgc(),
2504 "full gc");
2505
2506 op_full(cause);
2507 }
2508
2509 void ShenandoahHeap::entry_degenerated(int point) {
2510 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause);
2511 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc);
2512
2513 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point;
2514 const char* msg = degen_event_message(dpoint);
2515 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2516 EventMark em("%s", msg);
2517
2518 ShenandoahWorkerScope scope(workers(),
2519 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(),
2520 "stw degenerated gc");
2521
2522 set_degenerated_gc_in_progress(true);
2523 op_degenerated(dpoint);
2524 set_degenerated_gc_in_progress(false);
2525 }
2526
2527 void ShenandoahHeap::entry_mark() {
2528 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2529
2530 const char* msg = conc_mark_event_message();
2531 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2532 EventMark em("%s", msg);
2533
2534 ShenandoahWorkerScope scope(workers(),
2535 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(),
2536 "concurrent marking");
2537
2538 try_inject_alloc_failure();
2539 op_mark();
2540 }
2541
2542 void ShenandoahHeap::entry_evac() {
2543 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac);
2544 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2545
2546 static const char* msg = "Concurrent evacuation";
2547 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2548 EventMark em("%s", msg);
2549
2550 ShenandoahWorkerScope scope(workers(),
2551 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(),
2552 "concurrent evacuation");
2553
2554 try_inject_alloc_failure();
2555 op_conc_evac();
2556 }
2557
2558 void ShenandoahHeap::entry_updaterefs() {
2559 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs);
2560
2561 static const char* msg = "Concurrent update references";
2562 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2563 EventMark em("%s", msg);
2564
2565 ShenandoahWorkerScope scope(workers(),
2566 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(),
2567 "concurrent reference update");
2568
2569 try_inject_alloc_failure();
2570 op_updaterefs();
2571 }
2572 void ShenandoahHeap::entry_cleanup() {
2573 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup);
2574
2575 static const char* msg = "Concurrent cleanup";
2576 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2577 EventMark em("%s", msg);
2578
2579 // This phase does not use workers, no need for setup
2580
2581 try_inject_alloc_failure();
2582 op_cleanup();
2583 }
2584
2585 void ShenandoahHeap::entry_reset() {
2586 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset);
2587
2588 static const char* msg = "Concurrent reset";
2589 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2590 EventMark em("%s", msg);
2591
2592 ShenandoahWorkerScope scope(workers(),
2593 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(),
2594 "concurrent reset");
2595
2596 try_inject_alloc_failure();
2597 op_reset();
2598 }
2599
2600 void ShenandoahHeap::entry_preclean() {
2601 if (ShenandoahPreclean && process_references()) {
2602 static const char* msg = "Concurrent precleaning";
2603 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2604 EventMark em("%s", msg);
2605
2606 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean);
2607
2608 ShenandoahWorkerScope scope(workers(),
2609 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(),
2610 "concurrent preclean",
2611 /* check_workers = */ false);
2612
2613 try_inject_alloc_failure();
2614 op_preclean();
2615 }
2616 }
2617
2618 void ShenandoahHeap::entry_traversal() {
2619 static const char* msg = "Concurrent traversal";
2620 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2621 EventMark em("%s", msg);
2622
2623 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters());
2624
2625 ShenandoahWorkerScope scope(workers(),
2626 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(),
2627 "concurrent traversal");
2628
2629 try_inject_alloc_failure();
2630 op_traversal();
2631 }
2632
2633 void ShenandoahHeap::entry_uncommit(double shrink_before) {
2634 static const char *msg = "Concurrent uncommit";
2635 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true);
2636 EventMark em("%s", msg);
2637
2638 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit);
2639
2640 op_uncommit(shrink_before);
2641 }
2642
2643 void ShenandoahHeap::try_inject_alloc_failure() {
2644 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) {
2645 _inject_alloc_failure.set();
2646 os::naked_short_sleep(1);
2647 if (cancelled_gc()) {
2648 log_info(gc)("Allocation failure was successfully injected");
2649 }
2650 }
2651 }
2652
2653 bool ShenandoahHeap::should_inject_alloc_failure() {
2654 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset();
2655 }
2656
2657 void ShenandoahHeap::initialize_serviceability() {
2658 _memory_pool = new ShenandoahMemoryPool(this);
2659 _cycle_memory_manager.add_pool(_memory_pool);
2660 _stw_memory_manager.add_pool(_memory_pool);
2661 }
2662
2663 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() {
2664 GrowableArray<GCMemoryManager*> memory_managers(2);
2665 memory_managers.append(&_cycle_memory_manager);
2666 memory_managers.append(&_stw_memory_manager);
2667 return memory_managers;
2668 }
2669
2670 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() {
2671 GrowableArray<MemoryPool*> memory_pools(1);
2672 memory_pools.append(_memory_pool);
2673 return memory_pools;
2674 }
2675
2676 MemoryUsage ShenandoahHeap::memory_usage() {
2677 return _memory_pool->get_memory_usage();
2678 }
2679
2680 void ShenandoahHeap::enter_evacuation() {
2681 _oom_evac_handler.enter_evacuation();
2682 }
2683
2684 void ShenandoahHeap::leave_evacuation() {
2685 _oom_evac_handler.leave_evacuation();
2686 }
2687
2688 ShenandoahRegionIterator::ShenandoahRegionIterator() :
2689 _heap(ShenandoahHeap::heap()),
2690 _index(0) {}
2691
2692 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) :
2693 _heap(heap),
2694 _index(0) {}
2695
2696 void ShenandoahRegionIterator::reset() {
2697 _index = 0;
2698 }
2699
2700 bool ShenandoahRegionIterator::has_next() const {
2701 return _index < _heap->num_regions();
2702 }
2703
2704 char ShenandoahHeap::gc_state() const {
2705 return _gc_state.raw_value();
2706 }
2707
2708 void ShenandoahHeap::deduplicate_string(oop str) {
2709 assert(java_lang_String::is_instance(str), "invariant");
2710
2711 if (ShenandoahStringDedup::is_enabled()) {
2712 ShenandoahStringDedup::deduplicate(str);
2713 }
2714 }
2715
2716 const char* ShenandoahHeap::init_mark_event_message() const {
2717 bool update_refs = has_forwarded_objects();
2718 bool proc_refs = process_references();
2719 bool unload_cls = unload_classes();
2720
2721 if (update_refs && proc_refs && unload_cls) {
2722 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)";
2723 } else if (update_refs && proc_refs) {
2724 return "Pause Init Mark (update refs) (process weakrefs)";
2725 } else if (update_refs && unload_cls) {
2726 return "Pause Init Mark (update refs) (unload classes)";
2727 } else if (proc_refs && unload_cls) {
2728 return "Pause Init Mark (process weakrefs) (unload classes)";
2729 } else if (update_refs) {
2730 return "Pause Init Mark (update refs)";
2731 } else if (proc_refs) {
2732 return "Pause Init Mark (process weakrefs)";
2733 } else if (unload_cls) {
2734 return "Pause Init Mark (unload classes)";
2735 } else {
2736 return "Pause Init Mark";
2737 }
2738 }
2739
2740 const char* ShenandoahHeap::final_mark_event_message() const {
2741 bool update_refs = has_forwarded_objects();
2742 bool proc_refs = process_references();
2743 bool unload_cls = unload_classes();
2744
2745 if (update_refs && proc_refs && unload_cls) {
2746 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)";
2747 } else if (update_refs && proc_refs) {
2748 return "Pause Final Mark (update refs) (process weakrefs)";
2749 } else if (update_refs && unload_cls) {
2750 return "Pause Final Mark (update refs) (unload classes)";
2751 } else if (proc_refs && unload_cls) {
2752 return "Pause Final Mark (process weakrefs) (unload classes)";
2753 } else if (update_refs) {
2754 return "Pause Final Mark (update refs)";
2755 } else if (proc_refs) {
2756 return "Pause Final Mark (process weakrefs)";
2757 } else if (unload_cls) {
2758 return "Pause Final Mark (unload classes)";
2759 } else {
2760 return "Pause Final Mark";
2761 }
2762 }
2763
2764 const char* ShenandoahHeap::conc_mark_event_message() const {
2765 bool update_refs = has_forwarded_objects();
2766 bool proc_refs = process_references();
2767 bool unload_cls = unload_classes();
2768
2769 if (update_refs && proc_refs && unload_cls) {
2770 return "Concurrent marking (update refs) (process weakrefs) (unload classes)";
2771 } else if (update_refs && proc_refs) {
2772 return "Concurrent marking (update refs) (process weakrefs)";
2773 } else if (update_refs && unload_cls) {
2774 return "Concurrent marking (update refs) (unload classes)";
2775 } else if (proc_refs && unload_cls) {
2776 return "Concurrent marking (process weakrefs) (unload classes)";
2777 } else if (update_refs) {
2778 return "Concurrent marking (update refs)";
2779 } else if (proc_refs) {
2780 return "Concurrent marking (process weakrefs)";
2781 } else if (unload_cls) {
2782 return "Concurrent marking (unload classes)";
2783 } else {
2784 return "Concurrent marking";
2785 }
2786 }
2787
2788 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const {
2789 switch (point) {
2790 case _degenerated_unset:
2791 return "Pause Degenerated GC (<UNSET>)";
2792 case _degenerated_traversal:
2793 return "Pause Degenerated GC (Traversal)";
2794 case _degenerated_outside_cycle:
2795 return "Pause Degenerated GC (Outside of Cycle)";
2796 case _degenerated_mark:
2797 return "Pause Degenerated GC (Mark)";
2798 case _degenerated_evac:
2799 return "Pause Degenerated GC (Evacuation)";
2800 case _degenerated_updaterefs:
2801 return "Pause Degenerated GC (Update Refs)";
2802 default:
2803 ShouldNotReachHere();
2804 return "ERROR";
2805 }
2806 }
2807
2808 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) {
2809 #ifdef ASSERT
2810 assert(_liveness_cache != NULL, "sanity");
2811 assert(worker_id < _max_workers, "sanity");
2812 for (uint i = 0; i < num_regions(); i++) {
2813 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty");
2814 }
2815 #endif
2816 return _liveness_cache[worker_id];
2817 }
2818
2819 void ShenandoahHeap::flush_liveness_cache(uint worker_id) {
2820 assert(worker_id < _max_workers, "sanity");
2821 assert(_liveness_cache != NULL, "sanity");
2822 jushort* ld = _liveness_cache[worker_id];
2823 for (uint i = 0; i < num_regions(); i++) {
2824 ShenandoahHeapRegion* r = get_region(i);
2825 jushort live = ld[i];
2826 if (live > 0) {
2827 r->increase_live_data_gc_words(live);
2828 ld[i] = 0;
2829 }
2830 }
2831 }
2832
2833 size_t ShenandoahHeap::obj_size(oop obj) const {
2834 return CollectedHeap::obj_size(obj) + ShenandoahForwarding::word_size();
2835 }
2836
2837 ptrdiff_t ShenandoahHeap::cell_header_size() const {
2838 return ShenandoahForwarding::byte_size();
2839 }