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