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