1 /*
2 * Copyright (c) 2015, Red Hat, Inc. and/or its affiliates.
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 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP
25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP
26
27 #include "gc/shared/cmBitMap.inline.hpp"
28 #include "gc/shared/threadLocalAllocBuffer.inline.hpp"
29 #include "gc/shenandoah/brooksPointer.inline.hpp"
30 #include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
31 #include "gc/shenandoah/shenandoahHeap.hpp"
32 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
33 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
34 #include "oops/oop.inline.hpp"
35 #include "runtime/atomic.hpp"
36 #include "runtime/prefetch.hpp"
37 #include "runtime/prefetch.inline.hpp"
38 #include "utilities/copy.hpp"
39
40 /*
41 * Marks the object. Returns true if the object has not been marked before and has
42 * been marked by this thread. Returns false if the object has already been marked,
43 * or if a competing thread succeeded in marking this object.
44 */
45 inline bool ShenandoahHeap::mark_next(oop obj) const {
46 #ifdef ASSERT
47 if (! oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj))) {
48 tty->print_cr("heap region containing obj:");
49 ShenandoahHeapRegion* obj_region = heap_region_containing(obj);
50 obj_region->print();
51 tty->print_cr("heap region containing forwardee:");
52 ShenandoahHeapRegion* forward_region = heap_region_containing(oopDesc::bs()->read_barrier(obj));
53 forward_region->print();
54 }
55 #endif
56
57 assert(oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj)), "only mark forwarded copy of objects");
58 return mark_next_no_checks(obj);
59 }
60
61 inline bool ShenandoahHeap::mark_next_no_checks(oop obj) const {
62 HeapWord* addr = (HeapWord*) obj;
63 return (! allocated_after_next_mark_start(addr)) && _next_mark_bit_map->parMark(addr);
64 }
65
66 inline bool ShenandoahHeap::is_marked_next(oop obj) const {
67 HeapWord* addr = (HeapWord*) obj;
68 return allocated_after_next_mark_start(addr) || _next_mark_bit_map->isMarked(addr);
69 }
70
71 inline bool ShenandoahHeap::is_marked_complete(oop obj) const {
72 HeapWord* addr = (HeapWord*) obj;
73 return allocated_after_complete_mark_start(addr) || _complete_mark_bit_map->isMarked(addr);
74 }
75
76 inline bool ShenandoahHeap::need_update_refs() const {
77 return _need_update_refs;
78 }
79
80 inline uint ShenandoahHeap::heap_region_index_containing(const void* addr) const {
81 uintptr_t region_start = ((uintptr_t) addr);
82 uintptr_t index = (region_start - (uintptr_t) _first_region_bottom) >> ShenandoahHeapRegion::RegionSizeShift;
83 #ifdef ASSERT
84 if (!(index < _num_regions)) {
85 tty->print_cr("heap region does not contain address, first_region_bottom: "PTR_FORMAT \
86 ", real bottom of first region: "PTR_FORMAT", num_regions: "SIZE_FORMAT", region_size: "SIZE_FORMAT,
87 p2i(_first_region_bottom),
88 p2i(_ordered_regions->get(0)->bottom()),
89 _num_regions,
90 ShenandoahHeapRegion::RegionSizeBytes);
91 }
92 #endif
93 assert(index < _num_regions, "heap region index must be in range");
94 return index;
95 }
96
97 inline ShenandoahHeapRegion* ShenandoahHeap::heap_region_containing(const void* addr) const {
98 uint index = heap_region_index_containing(addr);
99 ShenandoahHeapRegion* result = _ordered_regions->get(index);
100 #ifdef ASSERT
101 if (!(addr >= result->bottom() && addr < result->end())) {
102 tty->print_cr("heap region does not contain address, first_region_bottom: "PTR_FORMAT \
103 ", real bottom of first region: "PTR_FORMAT", num_regions: "SIZE_FORMAT,
104 p2i(_first_region_bottom),
105 p2i(_ordered_regions->get(0)->bottom()),
106 _num_regions);
107 }
108 #endif
109 assert(addr >= result->bottom() && addr < result->end(), "address must be in found region");
110 return result;
111 }
112
113 template <class T>
114 inline oop ShenandoahHeap::update_oop_ref_not_null(T* p, oop obj) {
115 if (in_collection_set(obj)) {
116 oop forw = ShenandoahBarrierSet::resolve_oop_static_not_null(obj);
117 assert(! oopDesc::unsafe_equals(forw, obj) || is_full_gc_in_progress(), "expect forwarded object");
118 obj = forw;
119 oopDesc::encode_store_heap_oop(p, obj);
120 }
121 #ifdef ASSERT
122 else {
123 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "expect not forwarded");
124 }
125 #endif
126 return obj;
127 }
128
129 template <class T>
130 inline oop ShenandoahHeap::maybe_update_oop_ref(T* p) {
131 T o = oopDesc::load_heap_oop(p);
132 if (! oopDesc::is_null(o)) {
133 oop obj = oopDesc::decode_heap_oop_not_null(o);
134 return maybe_update_oop_ref_not_null(p, obj);
135 } else {
136 return NULL;
137 }
138 }
139
140 inline oop ShenandoahHeap::atomic_compare_exchange_oop(oop n, oop* addr, oop c) {
141 return (oop) Atomic::cmpxchg_ptr(n, addr, c);
142 }
143
144 inline oop ShenandoahHeap::atomic_compare_exchange_oop(oop n, narrowOop* addr, oop c) {
145 narrowOop cmp = oopDesc::encode_heap_oop(c);
146 narrowOop val = oopDesc::encode_heap_oop(n);
147 return oopDesc::decode_heap_oop((narrowOop) Atomic::cmpxchg(val, addr, cmp));
148 }
149
150 template <class T>
151 inline oop ShenandoahHeap::maybe_update_oop_ref_not_null(T* p, oop heap_oop) {
152
153 assert((! is_in(p)) || (! in_collection_set(p))
154 || is_full_gc_in_progress(),
155 "never update refs in from-space, unless evacuation has been cancelled");
156
157 #ifdef ASSERT
158 if (! is_in(heap_oop)) {
159 print_heap_regions();
160 tty->print_cr("object not in heap: "PTR_FORMAT", referenced by: "PTR_FORMAT, p2i((HeapWord*) heap_oop), p2i(p));
161 assert(is_in(heap_oop), "object must be in heap");
162 }
163 #endif
164 assert(is_in(heap_oop), "only ever call this on objects in the heap");
165 if (in_collection_set(heap_oop)) {
166 oop forwarded_oop = ShenandoahBarrierSet::resolve_oop_static_not_null(heap_oop); // read brooks ptr
167 assert(! oopDesc::unsafe_equals(forwarded_oop, heap_oop) || is_full_gc_in_progress(), "expect forwarded object");
168
169 log_develop_trace(gc)("Updating old ref: "PTR_FORMAT" pointing to "PTR_FORMAT" to new ref: "PTR_FORMAT,
170 p2i(p), p2i(heap_oop), p2i(forwarded_oop));
171
172 assert(forwarded_oop->is_oop(), "oop required");
173 assert(is_in(forwarded_oop), "forwardee must be in heap");
174 assert(oopDesc::bs()->is_safe(forwarded_oop), "forwardee must not be in collection set");
175 // If this fails, another thread wrote to p before us, it will be logged in SATB and the
176 // reference be updated later.
177 oop result = atomic_compare_exchange_oop(forwarded_oop, p, heap_oop);
178
179 if (oopDesc::unsafe_equals(result, heap_oop)) { // CAS successful.
180 return forwarded_oop;
181 } else {
182 return NULL;
183 }
184 } else {
185 assert(oopDesc::unsafe_equals(heap_oop, ShenandoahBarrierSet::resolve_oop_static_not_null(heap_oop)),
186 "expect not forwarded");
187 return heap_oop;
188 }
189 }
190
191 inline bool ShenandoahHeap::cancelled_concgc() const {
192 return (jbyte) OrderAccess::load_acquire((jbyte*) &_cancelled_concgc);
193 }
194
195 inline bool ShenandoahHeap::try_cancel_concgc() const {
196 return Atomic::cmpxchg(true, (jbyte*) &_cancelled_concgc, false) == false;
197 }
198
199 inline void ShenandoahHeap::set_cancelled_concgc(bool v) {
200 OrderAccess::release_store_fence((jbyte*) &_cancelled_concgc, (jbyte) v);
201 }
202
203 inline HeapWord* ShenandoahHeap::allocate_from_gclab(Thread* thread, size_t size) {
204 if (UseTLAB) {
205 HeapWord* obj = thread->gclab().allocate(size);
206 if (obj != NULL) {
207 return obj;
208 }
209 // Otherwise...
210 return allocate_from_gclab_slow(thread, size);
211 } else {
212 return NULL;
213 }
214 }
215
216 inline void ShenandoahHeap::copy_object(oop p, HeapWord* s, size_t words) {
217 assert(s != NULL, "allocation of brooks pointer must not fail");
218 HeapWord* copy = s + BrooksPointer::word_size();
219
220 guarantee(copy != NULL, "allocation of copy object must not fail");
221 Copy::aligned_disjoint_words((HeapWord*) p, copy, words);
222 BrooksPointer::initialize(oop(copy));
223
224 log_develop_trace(gc, compaction)("copy object from "PTR_FORMAT" to: "PTR_FORMAT, p2i((HeapWord*) p), p2i(copy));
225 }
226
227 inline oop ShenandoahHeap::evacuate_object(oop p, Thread* thread) {
228 size_t required;
229
230 #ifdef ASSERT
231 ShenandoahHeapRegion* hr = NULL;
232 if (ShenandoahVerifyReadsToFromSpace) {
233 hr = heap_region_containing(p);
234 {
235 hr->memProtectionOff();
236 required = BrooksPointer::word_size() + p->size();
237 hr->memProtectionOn();
238 }
239 } else {
240 required = BrooksPointer::word_size() + p->size();
241 }
242 #else
243 required = BrooksPointer::word_size() + p->size();
244 #endif
245
246 assert(! heap_region_containing(p)->is_humongous(), "never evacuate humongous objects");
247
248 bool alloc_from_gclab = true;
249 HeapWord* filler = allocate_from_gclab(thread, required);
250 if (filler == NULL) {
251 filler = allocate_memory(required, true);
252 alloc_from_gclab = false;
253 }
254
255 #ifdef ASSERT
256 // Checking that current Java thread does not hold Threads_lock when we get here.
257 // If that ever be the case, we'd deadlock in oom_during_evacuation.
258 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) {
259 assert(! Threads_lock->owned_by_self(), "must not hold Threads_lock here");
260 }
261 #endif
262
263 if (filler == NULL) {
264 oom_during_evacuation();
265 // If this is a Java thread, it should have waited
266 // until all GC threads are done, and then we
267 // return the forwardee.
268 oop resolved = ShenandoahBarrierSet::resolve_oop_static(p);
269 return resolved;
270 }
271
272 HeapWord* copy = filler + BrooksPointer::word_size();
273
274 #ifdef ASSERT
275 if (ShenandoahVerifyReadsToFromSpace) {
276 hr->memProtectionOff();
277 copy_object(p, filler, required - BrooksPointer::word_size());
278 hr->memProtectionOn();
279 } else {
280 copy_object(p, filler, required - BrooksPointer::word_size());
281 }
282 #else
283 copy_object(p, filler, required - BrooksPointer::word_size());
284 #endif
285
286 oop copy_val = oop(copy);
287 oop result = BrooksPointer::try_update_forwardee(p, copy_val);
288
289 oop return_val;
290 if (oopDesc::unsafe_equals(result, p)) {
291 return_val = copy_val;
292
293 log_develop_trace(gc, compaction)("Copy of "PTR_FORMAT" to "PTR_FORMAT" succeeded \n",
294 p2i((HeapWord*) p), p2i(copy));
295
296 #ifdef ASSERT
297 assert(return_val->is_oop(), "expect oop");
298 assert(p->klass() == return_val->klass(), "Should have the same class p: "PTR_FORMAT", copy: "PTR_FORMAT,
299 p2i((HeapWord*) p), p2i((HeapWord*) copy));
300 #endif
301 } else {
302 if (alloc_from_gclab) {
303 thread->gclab().rollback(required);
304 }
305 log_develop_trace(gc, compaction)("Copy of "PTR_FORMAT" to "PTR_FORMAT" failed, use other: "PTR_FORMAT,
306 p2i((HeapWord*) p), p2i(copy), p2i((HeapWord*) result));
307 return_val = result;
308 }
309
310 return return_val;
311 }
312
313 inline bool ShenandoahHeap::requires_marking(const void* entry) const {
314 return ! is_marked_next(oop(entry));
315 }
316
317 bool ShenandoahHeap::region_in_collection_set(size_t region_index) const {
318 return _in_cset_fast_test_base[region_index];
319 }
320
321 bool ShenandoahHeap::in_collection_set(ShenandoahHeapRegion* r) const {
322 return region_in_collection_set(r->region_number());
323 }
324
325 template <class T>
326 inline bool ShenandoahHeap::in_collection_set(T p) const {
327 HeapWord* obj = (HeapWord*) p;
328 assert(_in_cset_fast_test != NULL, "sanity");
329 assert(is_in(obj), "should be in heap");
330
331 // no need to subtract the bottom of the heap from obj,
332 // _in_cset_fast_test is biased
333 uintx index = ((uintx) obj) >> ShenandoahHeapRegion::RegionSizeShift;
334 return _in_cset_fast_test[index];
335 }
336
337 inline bool ShenandoahHeap::concurrent_mark_in_progress() {
338 return _concurrent_mark_in_progress != 0;
339 }
340
341 inline address ShenandoahHeap::concurrent_mark_in_progress_addr() {
342 return (address) &(ShenandoahHeap::heap()->_concurrent_mark_in_progress);
343 }
344
345 inline bool ShenandoahHeap::is_evacuation_in_progress() {
346 return _evacuation_in_progress != 0;
347 }
348
349 inline bool ShenandoahHeap::allocated_after_next_mark_start(HeapWord* addr) const {
350 uintx index = ((uintx) addr) >> ShenandoahHeapRegion::RegionSizeShift;
351 HeapWord* top_at_mark_start = _next_top_at_mark_starts[index];
352 bool alloc_after_mark_start = addr >= top_at_mark_start;
353 return alloc_after_mark_start;
354 }
355
356 inline bool ShenandoahHeap::allocated_after_complete_mark_start(HeapWord* addr) const {
357 uintx index = ((uintx) addr) >> ShenandoahHeapRegion::RegionSizeShift;
358 HeapWord* top_at_mark_start = _complete_top_at_mark_starts[index];
359 bool alloc_after_mark_start = addr >= top_at_mark_start;
360 return alloc_after_mark_start;
361 }
362
363 template<class T>
364 inline void ShenandoahHeap::marked_object_iterate(ShenandoahHeapRegion* region, T* cl) {
365 assert(BrooksPointer::word_offset() < 0, "skip_delta calculation below assumes the forwarding ptr is before obj");
366
367 CMBitMap* mark_bit_map = _complete_mark_bit_map;
368 HeapWord* top_at_mark_start = complete_top_at_mark_start(region->bottom());
369
370 size_t skip_bitmap_delta = BrooksPointer::word_size() + 1;
371 size_t skip_objsize_delta = BrooksPointer::word_size() /* + actual obj.size() below */;
372 HeapWord* start = region->bottom() + BrooksPointer::word_size();
373
374 HeapWord* limit = region->top();
375 HeapWord* end = MIN2(top_at_mark_start + BrooksPointer::word_size(), _ordered_regions->end());
376 HeapWord* addr = mark_bit_map->getNextMarkedWordAddress(start, end);
377
378 intx dist = ShenandoahMarkScanPrefetch;
379 if (dist > 0) {
380 // Batched scan that prefetches the oop data, anticipating the access to
381 // either header, oop field, or forwarding pointer. Not that we cannot
382 // touch anything in oop, while it still being prefetched to get enough
383 // time for prefetch to work. This is why we try to scan the bitmap linearly,
384 // disregarding the object size. However, since we know forwarding pointer
385 // preceeds the object, we can skip over it. Once we cannot trust the bitmap,
386 // there is no point for prefetching the oop contents, as oop->size() will
387 // touch it prematurely.
388
389 oop slots[dist];
390 bool aborting = false;
391 int avail;
392 do {
393 avail = 0;
394 for (int c = 0; (c < dist) && (addr < limit); c++) {
395 Prefetch::read(addr, 1);
396 oop obj = oop(addr);
397 slots[avail++] = obj;
398 if (addr < top_at_mark_start) {
399 addr += skip_bitmap_delta;
400 addr = mark_bit_map->getNextMarkedWordAddress(addr, end);
401 } else {
402 // cannot trust mark bitmap anymore, finish the current stride,
403 // and switch to accurate traversal
404 addr += obj->size() + skip_objsize_delta;
405 aborting = true;
406 }
407 }
408
409 for (int c = 0; c < avail; c++) {
410 do_marked_object(mark_bit_map, cl, slots[c]);
411 }
412 } while (avail > 0 && !aborting);
413
414 // accurate traversal
415 while (addr < limit) {
416 oop obj = oop(addr);
417 int size = obj->size();
418 do_marked_object(mark_bit_map, cl, obj);
419 addr += size + skip_objsize_delta;
420 }
421 } else {
422 while (addr < limit) {
423 oop obj = oop(addr);
424 int size = obj->size();
425 do_marked_object(mark_bit_map, cl, obj);
426 addr += size + skip_objsize_delta;
427 if (addr < top_at_mark_start) {
428 addr = mark_bit_map->getNextMarkedWordAddress(addr, end);
429 }
430 }
431 }
432 }
433
434 template<class T>
435 inline void ShenandoahHeap::do_marked_object(CMBitMap* bitmap, T* cl, oop obj) {
436 #ifdef ASSERT
437 assert(!oopDesc::is_null(obj), "sanity");
438 assert(obj->is_oop(), "sanity");
439 assert(is_in(obj), "sanity");
440 assert(bitmap == _complete_mark_bit_map, "only iterate completed mark bitmap");
441 assert(is_marked_complete(obj), "object expected to be marked");
442 #endif
443 cl->do_object(obj);
444 }
445
446 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP