1 /*
2 * Copyright (c) 2013, 2018, 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 "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
26 #include "gc_implementation/shenandoah/shenandoahAsserts.hpp"
27 #include "gc_implementation/shenandoah/shenandoahBarrierSet.hpp"
28 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp"
29 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp"
30 #include "gc_implementation/shenandoah/shenandoahHeuristics.hpp"
31 #include "runtime/interfaceSupport.hpp"
32 #include "utilities/macros.hpp"
33
34 #ifdef COMPILER1
35 #include "gc_implementation/shenandoah/shenandoahBarrierSetC1.hpp"
36 #endif
37 #ifdef COMPILER2
38 #include "gc_implementation/shenandoah/shenandoahBarrierSetC2.hpp"
39 #endif
40
41 #if defined(TARGET_ARCH_aarch64)
42 #include "shenandoahBarrierSetAssembler_aarch64.hpp"
43 #elif defined(TARGET_ARCH_x86)
44 #include "shenandoahBarrierSetAssembler_x86.hpp"
45 #else
46 #include "shenandoahBarrierSetAssembler_stub.hpp"
47 #endif
48
49 template <bool STOREVAL_EVAC_BARRIER>
50 class ShenandoahUpdateRefsForOopClosure: public ExtendedOopClosure {
51 private:
52 ShenandoahHeap* _heap;
53 ShenandoahBarrierSet* _bs;
54
55 template <class T>
56 inline void do_oop_work(T* p) {
57 oop o;
58 if (STOREVAL_EVAC_BARRIER) {
59 o = _heap->evac_update_with_forwarded(p);
60 if (!oopDesc::is_null(o)) {
61 _bs->enqueue(o);
62 }
63 } else {
64 _heap->maybe_update_with_forwarded(p);
65 }
66 }
67 public:
68 ShenandoahUpdateRefsForOopClosure() : _heap(ShenandoahHeap::heap()), _bs(ShenandoahBarrierSet::barrier_set()) {
69 assert(UseShenandoahGC && ShenandoahCloneBarrier, "should be enabled");
70 }
71
72 virtual void do_oop(oop* p) { do_oop_work(p); }
73 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
74 };
75
76 ShenandoahBarrierSet::ShenandoahBarrierSet(ShenandoahHeap* heap) :
77 BarrierSet(),
78 _heap(heap),
79 _bsasm(new ShenandoahBarrierSetAssembler()),
80 _bsc1(COMPILER1_PRESENT(new ShenandoahBarrierSetC1()) NOT_COMPILER1(NULL)),
81 _bsc2(COMPILER2_PRESENT(new ShenandoahBarrierSetC2()) NOT_COMPILER2(NULL))
82 {
83 _kind = BarrierSet::ShenandoahBarrierSet;
84 }
85
86 ShenandoahBarrierSetAssembler* ShenandoahBarrierSet::bsasm() const {
87 return _bsasm;
88 }
89
90 ShenandoahBarrierSetC1* ShenandoahBarrierSet::bsc1() const {
91 return _bsc1;
92 }
93
94 ShenandoahBarrierSetC2* ShenandoahBarrierSet::bsc2() const {
95 return _bsc2;
96 }
97
98 void ShenandoahBarrierSet::print_on(outputStream* st) const {
99 st->print("ShenandoahBarrierSet");
100 }
101
102 bool ShenandoahBarrierSet::is_a(BarrierSet::Name bsn) {
103 return bsn == BarrierSet::ShenandoahBarrierSet;
104 }
105
106 bool ShenandoahBarrierSet::has_read_prim_array_opt() {
107 return true;
108 }
109
110 bool ShenandoahBarrierSet::has_read_prim_barrier() {
111 return false;
112 }
113
114 bool ShenandoahBarrierSet::has_read_ref_array_opt() {
115 return true;
116 }
117
118 bool ShenandoahBarrierSet::has_read_ref_barrier() {
119 return false;
120 }
121
122 bool ShenandoahBarrierSet::has_read_region_opt() {
123 return true;
124 }
125
126 bool ShenandoahBarrierSet::has_write_prim_array_opt() {
127 return true;
128 }
129
130 bool ShenandoahBarrierSet::has_write_prim_barrier() {
131 return false;
132 }
133
134 bool ShenandoahBarrierSet::has_write_ref_array_opt() {
135 return true;
136 }
137
138 bool ShenandoahBarrierSet::has_write_ref_barrier() {
139 return true;
140 }
141
142 bool ShenandoahBarrierSet::has_write_ref_pre_barrier() {
143 return true;
144 }
145
146 bool ShenandoahBarrierSet::has_write_region_opt() {
147 return true;
148 }
149
150 bool ShenandoahBarrierSet::is_aligned(HeapWord* hw) {
151 return true;
152 }
153
154 bool ShenandoahBarrierSet::read_prim_needs_barrier(HeapWord* hw, size_t s) {
155 return false;
156 }
157
158 void ShenandoahBarrierSet::read_ref_field(void* v) {
159 // tty->print_cr("read_ref_field: v = "PTR_FORMAT, v);
160 // return *v;
161 }
162
163 template <class T, bool STOREVAL_EVAC_BARRIER>
164 void ShenandoahBarrierSet::write_ref_array_loop(HeapWord* start, size_t count) {
165 assert(UseShenandoahGC && ShenandoahCloneBarrier, "should be enabled");
166 ShenandoahUpdateRefsForOopClosure<STOREVAL_EVAC_BARRIER> cl;
167 T* dst = (T*) start;
168 for (size_t i = 0; i < count; i++) {
169 cl.do_oop(dst++);
170 }
171 }
172
173 void ShenandoahBarrierSet::write_ref_array(HeapWord* start, size_t count) {
174 assert(UseShenandoahGC, "should be enabled");
175 if (!ShenandoahCloneBarrier) return;
176 if (!need_update_refs_barrier()) return;
177
178 if (_heap->is_concurrent_traversal_in_progress()) {
179 ShenandoahEvacOOMScope oom_evac_scope;
180 if (UseCompressedOops) {
181 write_ref_array_loop<narrowOop, /* evac = */ true>(start, count);
182 } else {
183 write_ref_array_loop<oop, /* evac = */ true>(start, count);
184 }
185 } else {
186 if (UseCompressedOops) {
187 write_ref_array_loop<narrowOop, /* evac = */ false>(start, count);
188 } else {
189 write_ref_array_loop<oop, /* evac = */ false>(start, count);
190 }
191 }
192 }
193
194 template <class T>
195 void ShenandoahBarrierSet::write_ref_array_pre_work(T* dst, size_t count) {
196 assert (UseShenandoahGC && ShenandoahSATBBarrier, "Should be enabled");
197
198 shenandoah_assert_not_in_cset_loc_except(dst, _heap->cancelled_gc());
199
200 if (! JavaThread::satb_mark_queue_set().is_active()) return;
201 T* elem_ptr = dst;
202 for (size_t i = 0; i < count; i++, elem_ptr++) {
203 T heap_oop = oopDesc::load_heap_oop(elem_ptr);
204 if (!oopDesc::is_null(heap_oop)) {
205 enqueue(oopDesc::decode_heap_oop_not_null(heap_oop));
206 }
207 }
208 }
209
210 void ShenandoahBarrierSet::write_ref_array_pre(oop* dst, int count, bool dest_uninitialized) {
211 if (! dest_uninitialized && ShenandoahSATBBarrier) {
212 write_ref_array_pre_work(dst, (size_t)count);
213 }
214 }
215
216 void ShenandoahBarrierSet::write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized) {
217 if (! dest_uninitialized && ShenandoahSATBBarrier) {
218 write_ref_array_pre_work(dst, (size_t)count);
219 }
220 }
221
222 template <class T>
223 inline void ShenandoahBarrierSet::inline_write_ref_field_pre(T* field, oop newVal) {
224 newVal = load_reference_barrier(newVal);
225 storeval_barrier(newVal);
226 if (ShenandoahSATBBarrier) {
227 T heap_oop = oopDesc::load_heap_oop(field);
228 shenandoah_assert_not_in_cset_loc_except(field, ShenandoahHeap::heap()->cancelled_gc());
229 if (!oopDesc::is_null(heap_oop)) {
230 ShenandoahBarrierSet::barrier_set()->enqueue(oopDesc::decode_heap_oop(heap_oop));
231 }
232 }
233 }
234
235 // These are the more general virtual versions.
236 void ShenandoahBarrierSet::write_ref_field_pre_work(oop* field, oop new_val) {
237 inline_write_ref_field_pre(field, new_val);
238 }
239
240 void ShenandoahBarrierSet::write_ref_field_pre_work(narrowOop* field, oop new_val) {
241 inline_write_ref_field_pre(field, new_val);
242 }
243
244 void ShenandoahBarrierSet::write_ref_field_work(void* v, oop o, bool release) {
245 shenandoah_assert_not_in_cset_loc_except(v, _heap->cancelled_gc());
246 shenandoah_assert_not_forwarded_except (v, o, o == NULL || _heap->cancelled_gc() || !_heap->is_concurrent_mark_in_progress());
247 shenandoah_assert_not_in_cset_except (v, o, o == NULL || _heap->cancelled_gc() || !_heap->is_concurrent_mark_in_progress());
248 }
249
250 void ShenandoahBarrierSet::write_region_work(MemRegion mr) {
251 assert(UseShenandoahGC, "should be enabled");
252 if (!ShenandoahCloneBarrier) return;
253 if (! need_update_refs_barrier()) return;
254
255 // This is called for cloning an object (see jvm.cpp) after the clone
256 // has been made. We are not interested in any 'previous value' because
257 // it would be NULL in any case. But we *are* interested in any oop*
258 // that potentially need to be updated.
259
260 oop obj = oop(mr.start());
261 shenandoah_assert_correct(NULL, obj);
262 if (_heap->is_concurrent_traversal_in_progress()) {
263 ShenandoahEvacOOMScope oom_evac_scope;
264 ShenandoahUpdateRefsForOopClosure</* evac = */ true> cl;
265 obj->oop_iterate(&cl);
266 } else {
267 ShenandoahUpdateRefsForOopClosure</* evac = */ false> cl;
268 obj->oop_iterate(&cl);
269 }
270 }
271
272 oop ShenandoahBarrierSet::load_reference_barrier_not_null(oop obj) {
273 assert(obj != NULL, "");
274 if (ShenandoahLoadRefBarrier && _heap->has_forwarded_objects()) {
275 return load_reference_barrier_impl(obj);
276 } else {
277 return obj;
278 }
279 }
280
281 oop ShenandoahBarrierSet::load_reference_barrier(oop obj) {
282 if (obj != NULL) {
283 return load_reference_barrier_not_null(obj);
284 } else {
285 return obj;
286 }
287 }
288
289
290 oop ShenandoahBarrierSet::load_reference_barrier_mutator(oop obj) {
291 assert(ShenandoahLoadRefBarrier, "should be enabled");
292 assert(_heap->is_gc_in_progress_mask(ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL), "evac should be in progress");
293 shenandoah_assert_in_cset(NULL, obj);
294
295 oop fwd = resolve_forwarded_not_null(obj);
296 if (obj == fwd) {
297 ShenandoahEvacOOMScope oom_evac_scope;
298
299 Thread* thread = Thread::current();
300 oop res_oop = _heap->evacuate_object(obj, thread);
301
302 // Since we are already here and paid the price of getting through runtime call adapters
303 // and acquiring oom-scope, it makes sense to try and evacuate more adjacent objects,
304 // thus amortizing the overhead. For sparsely live heaps, scan costs easily dominate
305 // total assist costs, and can introduce a lot of evacuation latency. This is why we
306 // only scan for _nearest_ N objects, regardless if they are eligible for evac or not.
307 // The scan itself should also avoid touching the non-marked objects below TAMS, because
308 // their metadata (notably, klasses) may be incorrect already.
309
310 size_t max = ShenandoahEvacAssist;
311 if (max > 0) {
312 // Traversal is special: it uses incomplete marking context, because it coalesces evac with mark.
313 // Other code uses complete marking context, because evac happens after the mark.
314 ShenandoahMarkingContext* ctx = _heap->is_concurrent_traversal_in_progress() ?
315 _heap->marking_context() : _heap->complete_marking_context();
316
317 ShenandoahHeapRegion* r = _heap->heap_region_containing(obj);
318 assert(r->is_cset(), "sanity");
319
320 HeapWord* cur = (HeapWord*)obj + obj->size();
321
322 size_t count = 0;
323 while ((cur < r->top()) && ctx->is_marked(oop(cur)) && (count++ < max)) {
324 oop cur_oop = oop(cur);
325 if (cur_oop == resolve_forwarded_not_null(cur_oop)) {
326 _heap->evacuate_object(cur_oop, thread);
327 }
328 cur = cur + cur_oop->size();
329 }
330 }
331
332 return res_oop;
333 }
334 return fwd;
335 }
336
337 oop ShenandoahBarrierSet::load_reference_barrier_impl(oop obj) {
338 assert(ShenandoahLoadRefBarrier, "should be enabled");
339 if (!oopDesc::is_null(obj)) {
340 bool evac_in_progress = _heap->is_gc_in_progress_mask(ShenandoahHeap::EVACUATION | ShenandoahHeap::TRAVERSAL);
341 oop fwd = resolve_forwarded_not_null(obj);
342 if (evac_in_progress &&
343 _heap->in_collection_set(obj) &&
344 obj == fwd) {
345 Thread *t = Thread::current();
346 if (t->is_GC_task_thread()) {
347 return _heap->evacuate_object(obj, t);
348 } else {
349 ShenandoahEvacOOMScope oom_evac_scope;
350 return _heap->evacuate_object(obj, t);
351 }
352 } else {
353 return fwd;
354 }
355 } else {
356 return obj;
357 }
358 }
359
360 void ShenandoahBarrierSet::storeval_barrier(oop obj) {
361 if (ShenandoahStoreValEnqueueBarrier && !oopDesc::is_null(obj) && _heap->is_concurrent_traversal_in_progress()) {
362 enqueue(obj);
363 }
364 }
365
366 void ShenandoahBarrierSet::keep_alive_barrier(oop obj) {
367 if (ShenandoahKeepAliveBarrier && _heap->is_concurrent_mark_in_progress()) {
368 enqueue(obj);
369 }
370 }
371
372 void ShenandoahBarrierSet::enqueue(oop obj) {
373 shenandoah_assert_not_forwarded_if(NULL, obj, _heap->is_concurrent_traversal_in_progress());
374
375 // Filter marked objects before hitting the SATB queues. The same predicate would
376 // be used by SATBMQ::filter to eliminate already marked objects downstream, but
377 // filtering here helps to avoid wasteful SATB queueing work to begin with.
378 if (!_heap->requires_marking(obj)) return;
379
380 G1SATBCardTableModRefBS::enqueue(obj);
381 }
382
383 oop ShenandoahBarrierSet::atomic_compare_exchange_oop(oop exchange_value,
384 volatile HeapWord *dest,
385 oop compare_value) {
386 if (UseCompressedOops) {
387 // encode exchange and compare value from oop to T
388 narrowOop val = oopDesc::encode_heap_oop(exchange_value);
389 narrowOop cmp = oopDesc::encode_heap_oop(compare_value);
390
391 narrowOop old = (narrowOop) Atomic::cmpxchg(val, (narrowOop*)dest, cmp);
392 // decode old from T to oop
393 return oopDesc::decode_heap_oop(old);
394 } else {
395 return (oop)Atomic::cmpxchg_ptr(exchange_value, (oop*)dest, compare_value);
396 }
397 }
398
399 oop ShenandoahBarrierSet::oop_atomic_cmpxchg_in_heap(oop new_value, volatile HeapWord* dest, oop compare_value) {
400 oop expected;
401 bool success;
402 do {
403 expected = compare_value;
404 compare_value = atomic_compare_exchange_oop(new_value, dest, expected);
405 success = (compare_value == expected);
406 } while ((! success) && resolve_forwarded(compare_value) == resolve_forwarded(expected));
407 oop result = load_reference_barrier(compare_value);
408 if (ShenandoahSATBBarrier && success && result != NULL) {
409 enqueue(result);
410 }
411 if (new_value != NULL) {
412 storeval_barrier(new_value);
413 }
414 return result;
415 }