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 12  * version 2 for more details (a copy is included in the LICENSE file that
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 24 
 25 #ifndef SHARE_GC_G1_HEAPREGION_INLINE_HPP
 26 #define SHARE_GC_G1_HEAPREGION_INLINE_HPP
 27 
 28 #include "gc/g1/heapRegion.hpp"
 29 
 30 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
 31 #include "gc/g1/g1CollectedHeap.inline.hpp"
 32 #include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
 33 #include "gc/g1/g1Predictions.hpp"
 34 #include "oops/oop.inline.hpp"
 35 #include "runtime/atomic.hpp"
 36 #include "runtime/prefetch.inline.hpp"
 37 #include "utilities/align.hpp"
 38 #include "utilities/globalDefinitions.hpp"
 39 
 40 inline HeapWord* HeapRegion::allocate_impl(size_t min_word_size,
 41                                            size_t desired_word_size,
 42                                            size_t* actual_size) {
 43   HeapWord* obj = top();
 44   size_t available = pointer_delta(end(), obj);
 45   size_t want_to_allocate = MIN2(available, desired_word_size);
 46   if (want_to_allocate >= min_word_size) {
 47     HeapWord* new_top = obj + want_to_allocate;
 48     set_top(new_top);
 49     assert(is_object_aligned(obj) && is_object_aligned(new_top), "checking alignment");
 50     *actual_size = want_to_allocate;
 51     return obj;
 52   } else {
 53     return NULL;
 54   }
 55 }
 56 
 57 inline HeapWord* HeapRegion::par_allocate_impl(size_t min_word_size,
 58                                                size_t desired_word_size,
 59                                                size_t* actual_size) {
 60   do {
 61     HeapWord* obj = top();
 62     size_t available = pointer_delta(end(), obj);
 63     size_t want_to_allocate = MIN2(available, desired_word_size);
 64     if (want_to_allocate >= min_word_size) {
 65       HeapWord* new_top = obj + want_to_allocate;
 66       HeapWord* result = Atomic::cmpxchg(&_top, obj, new_top);
 67       // result can be one of two:
 68       //  the old top value: the exchange succeeded
 69       //  otherwise: the new value of the top is returned.
 70       if (result == obj) {
 71         assert(is_object_aligned(obj) && is_object_aligned(new_top), "checking alignment");
 72         *actual_size = want_to_allocate;
 73         return obj;
 74       }
 75     } else {
 76       return NULL;
 77     }
 78   } while (true);
 79 }
 80 
 81 inline HeapWord* HeapRegion::allocate(size_t min_word_size,
 82                                       size_t desired_word_size,
 83                                       size_t* actual_size) {
 84   HeapWord* res = allocate_impl(min_word_size, desired_word_size, actual_size);
 85   if (res != NULL) {
 86     _bot_part.alloc_block(res, *actual_size);
 87   }
 88   return res;
 89 }
 90 
 91 inline HeapWord* HeapRegion::allocate(size_t word_size) {
 92   size_t temp;
 93   return allocate(word_size, word_size, &temp);
 94 }
 95 
 96 inline HeapWord* HeapRegion::par_allocate(size_t word_size) {
 97   size_t temp;
 98   return par_allocate(word_size, word_size, &temp);
 99 }
100 
101 // Because of the requirement of keeping "_offsets" up to date with the
102 // allocations, we sequentialize these with a lock.  Therefore, best if
103 // this is used for larger LAB allocations only.
104 inline HeapWord* HeapRegion::par_allocate(size_t min_word_size,
105                                           size_t desired_word_size,
106                                           size_t* actual_size) {
107   MutexLocker x(&_par_alloc_lock);
108   return allocate(min_word_size, desired_word_size, actual_size);
109 }
110 
111 inline HeapWord* HeapRegion::block_start(const void* p) {
112   return _bot_part.block_start(p);
113 }
114 
115 inline HeapWord* HeapRegion::block_start_const(const void* p) const {
116   return _bot_part.block_start_const(p);
117 }
118 
119 inline bool HeapRegion::is_obj_dead_with_size(const oop obj, const G1CMBitMap* const prev_bitmap, size_t* size) const {
120   HeapWord* addr = cast_from_oop<HeapWord*>(obj);
121 
122   assert(addr < top(), "must be");
123   assert(!is_closed_archive(),
124          "Closed archive regions should not have references into other regions");
125   assert(!is_humongous(), "Humongous objects not handled here");
126   bool obj_is_dead = is_obj_dead(obj, prev_bitmap);
127 
128   if (ClassUnloading && obj_is_dead) {
129     assert(!block_is_obj(addr), "must be");
130     *size = block_size_using_bitmap(addr, prev_bitmap);
131   } else {
132     assert(block_is_obj(addr), "must be");
133     *size = obj->size();
134   }
135   return obj_is_dead;
136 }
137 
138 inline bool HeapRegion::block_is_obj(const HeapWord* p) const {
139   G1CollectedHeap* g1h = G1CollectedHeap::heap();
140 
141   if (!this->is_in(p)) {
142     assert(is_continues_humongous(), "This case can only happen for humongous regions");
143     return (p == humongous_start_region()->bottom());
144   }
145   // When class unloading is enabled it is not safe to only consider top() to conclude if the
146   // given pointer is a valid object. The situation can occur both for class unloading in a
147   // Full GC and during a concurrent cycle.
148   // During a Full GC regions can be excluded from compaction due to high live ratio, and
149   // because of this there can be stale objects for unloaded classes left in these regions.
150   // During a concurrent cycle class unloading is done after marking is complete and objects
151   // for the unloaded classes will be stale until the regions are collected.
152   if (ClassUnloading) {
153     return !g1h->is_obj_dead(cast_to_oop(p), this);
154   }
155   return p < top();
156 }
157 
158 inline size_t HeapRegion::block_size_using_bitmap(const HeapWord* addr, const G1CMBitMap* const prev_bitmap) const {
159   assert(ClassUnloading,
160          "All blocks should be objects if class unloading isn't used, so this method should not be called. "
161          "HR: [" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT ") "
162          "addr: " PTR_FORMAT,
163          p2i(bottom()), p2i(top()), p2i(end()), p2i(addr));
164 
165   // Old regions' dead objects may have dead classes
166   // We need to find the next live object using the bitmap
167   HeapWord* next = prev_bitmap->get_next_marked_addr(addr, prev_top_at_mark_start());
168 
169   assert(next > addr, "must get the next live object");
170   return pointer_delta(next, addr);
171 }
172 
173 inline bool HeapRegion::is_obj_dead(const oop obj, const G1CMBitMap* const prev_bitmap) const {
174   assert(is_in_reserved(obj), "Object " PTR_FORMAT " must be in region", p2i(obj));
175   return !obj_allocated_since_prev_marking(obj) &&
176          !prev_bitmap->is_marked(obj) &&
177          !is_closed_archive();
178 }
179 
180 template <bool RESOLVE>
181 inline size_t HeapRegion::block_size(const HeapWord *addr) const {
182   if (addr == top()) {
183     return pointer_delta(end(), addr);
184   }
185 
186   if (block_is_obj(addr)) {
187     oop obj = cast_to_oop(addr);
188 #ifdef _LP64
189 #ifdef ASSERT
190     if (RESOLVE) {
191       assert(UseCompactObjectHeaders && !G1CollectedHeap::heap()->collector_state()->in_full_gc(), "Illegal/excessive resolve during full-GC");
192     } else {
193       assert(!UseCompactObjectHeaders || G1CollectedHeap::heap()->collector_state()->in_full_gc() || !obj->is_forwarded(), "Missing resolve when forwarded during normal GC");
194     }
195 #endif
196     if (RESOLVE && obj->is_forwarded()) {
197       obj = obj->forwardee();
198     }
199 #endif
200     return obj->size();
201   }
202 
203   return block_size_using_bitmap(addr, G1CollectedHeap::heap()->concurrent_mark()->prev_mark_bitmap());
204 }
205 
206 inline void HeapRegion::reset_compaction_top_after_compaction() {
207   set_top(compaction_top());
208   _compaction_top = bottom();
209 }
210 
211 inline void HeapRegion::reset_compacted_after_full_gc() {
212   assert(!is_pinned(), "must be");
213 
214   reset_compaction_top_after_compaction();
215   // After a compaction the mark bitmap in a non-pinned regions is invalid.
216   // We treat all objects as being above PTAMS.
217   zero_marked_bytes();
218   init_top_at_mark_start();
219 
220   reset_after_full_gc_common();
221 }
222 
223 inline void HeapRegion::reset_skip_compacting_after_full_gc() {
224   assert(!is_free(), "must be");
225 
226   assert(compaction_top() == bottom(),
227          "region %u compaction_top " PTR_FORMAT " must not be different from bottom " PTR_FORMAT,
228          hrm_index(), p2i(compaction_top()), p2i(bottom()));
229 
230   _prev_top_at_mark_start = top(); // Keep existing top and usage.
231   _prev_marked_bytes = used();
232   _next_top_at_mark_start = bottom();
233   _next_marked_bytes = 0;
234 
235   reset_after_full_gc_common();
236 }
237 
238 inline void HeapRegion::reset_after_full_gc_common() {
239   if (is_empty()) {
240     reset_bot();
241   }
242 
243   // Clear unused heap memory in debug builds.
244   if (ZapUnusedHeapArea) {
245     mangle_unused_area();
246   }
247 }
248 
249 template<typename ApplyToMarkedClosure>
250 inline void HeapRegion::apply_to_marked_objects(G1CMBitMap* bitmap, ApplyToMarkedClosure* closure) {
251   HeapWord* limit = top();
252   HeapWord* next_addr = bottom();
253 
254   while (next_addr < limit) {
255     Prefetch::write(next_addr, PrefetchScanIntervalInBytes);
256     // This explicit is_marked check is a way to avoid
257     // some extra work done by get_next_marked_addr for
258     // the case where next_addr is marked.
259     if (bitmap->is_marked(next_addr)) {
260       oop current = cast_to_oop(next_addr);
261       next_addr += closure->apply(current);
262     } else {
263       next_addr = bitmap->get_next_marked_addr(next_addr, limit);
264     }
265   }
266 
267   assert(next_addr == limit, "Should stop the scan at the limit.");
268 }
269 
270 inline HeapWord* HeapRegion::par_allocate_no_bot_updates(size_t min_word_size,
271                                                          size_t desired_word_size,
272                                                          size_t* actual_word_size) {
273   assert(is_young(), "we can only skip BOT updates on young regions");
274   return par_allocate_impl(min_word_size, desired_word_size, actual_word_size);
275 }
276 
277 inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t word_size) {
278   size_t temp;
279   return allocate_no_bot_updates(word_size, word_size, &temp);
280 }
281 
282 inline HeapWord* HeapRegion::allocate_no_bot_updates(size_t min_word_size,
283                                                      size_t desired_word_size,
284                                                      size_t* actual_word_size) {
285   assert(is_young(), "we can only skip BOT updates on young regions");
286   return allocate_impl(min_word_size, desired_word_size, actual_word_size);
287 }
288 
289 inline void HeapRegion::note_start_of_marking() {
290   _next_marked_bytes = 0;
291   _next_top_at_mark_start = top();
292   _gc_efficiency = -1.0;
293 }
294 
295 inline void HeapRegion::note_end_of_marking() {
296   _prev_top_at_mark_start = _next_top_at_mark_start;
297   _next_top_at_mark_start = bottom();
298   _prev_marked_bytes = _next_marked_bytes;
299   _next_marked_bytes = 0;
300 }
301 
302 inline bool HeapRegion::in_collection_set() const {
303   return G1CollectedHeap::heap()->is_in_cset(this);
304 }
305 
306 template <class Closure, bool is_gc_active>
307 HeapWord* HeapRegion::do_oops_on_memregion_in_humongous(MemRegion mr,
308                                                         Closure* cl,
309                                                         G1CollectedHeap* g1h) {
310   assert(is_humongous(), "precondition");
311   HeapRegion* sr = humongous_start_region();
312   oop obj = cast_to_oop(sr->bottom());
313 
314   // If concurrent and klass_or_null is NULL, then space has been
315   // allocated but the object has not yet been published by setting
316   // the klass.  That can only happen if the card is stale.  However,
317   // we've already set the card clean, so we must return failure,
318   // since the allocating thread could have performed a write to the
319   // card that might be missed otherwise.
320   if (!is_gc_active && (obj->klass_or_null_acquire() == NULL)) {
321     return NULL;
322   }
323 
324   // We have a well-formed humongous object at the start of sr.
325   // Only filler objects follow a humongous object in the containing
326   // regions, and we can ignore those.  So only process the one
327   // humongous object.
328   if (g1h->is_obj_dead(obj, sr)) {
329     // The object is dead. There can be no other object in this region, so return
330     // the end of that region.
331     return end();
332   }
333   if (obj->is_objArray() || (sr->bottom() < mr.start())) {
334     // objArrays are always marked precisely, so limit processing
335     // with mr.  Non-objArrays might be precisely marked, and since
336     // it's humongous it's worthwhile avoiding full processing.
337     // However, the card could be stale and only cover filler
338     // objects.  That should be rare, so not worth checking for;
339     // instead let it fall out from the bounded iteration.
340     obj->oop_iterate(cl, mr);
341     return mr.end();
342   } else {
343     // If obj is not an objArray and mr contains the start of the
344     // obj, then this could be an imprecise mark, and we need to
345     // process the entire object.
346     int size = obj->oop_iterate_size(cl);
347     // We have scanned to the end of the object, but since there can be no objects
348     // after this humongous object in the region, we can return the end of the
349     // region if it is greater.
350     return MAX2(cast_from_oop<HeapWord*>(obj) + size, mr.end());
351   }
352 }
353 
354 template <bool is_gc_active, class Closure>
355 HeapWord* HeapRegion::oops_on_memregion_seq_iterate_careful(MemRegion mr,
356                                                             Closure* cl) {
357   assert(MemRegion(bottom(), end()).contains(mr), "Card region not in heap region");
358   G1CollectedHeap* g1h = G1CollectedHeap::heap();
359 
360   // Special handling for humongous regions.
361   if (is_humongous()) {
362     return do_oops_on_memregion_in_humongous<Closure, is_gc_active>(mr, cl, g1h);
363   }
364   assert(is_old() || is_archive(), "Wrongly trying to iterate over region %u type %s", _hrm_index, get_type_str());
365 
366   // Because mr has been trimmed to what's been allocated in this
367   // region, the parts of the heap that are examined here are always
368   // parsable; there's no need to use klass_or_null to detect
369   // in-progress allocation.
370 
371   // Cache the boundaries of the memory region in some const locals
372   HeapWord* const start = mr.start();
373   HeapWord* const end = mr.end();
374 
375   // Find the obj that extends onto mr.start().
376   // Update BOT as needed while finding start of (possibly dead)
377   // object containing the start of the region.
378   HeapWord* cur = block_start(start);
379 
380 #ifdef ASSERT
381   {
382     assert(cur <= start,
383            "cur: " PTR_FORMAT ", start: " PTR_FORMAT, p2i(cur), p2i(start));
384     HeapWord* next = cur + block_size(cur);
385     assert(start < next,
386            "start: " PTR_FORMAT ", next: " PTR_FORMAT, p2i(start), p2i(next));
387   }
388 #endif
389 
390   const G1CMBitMap* const bitmap = g1h->concurrent_mark()->prev_mark_bitmap();
391   while (true) {
392     oop obj = cast_to_oop(cur);
393     assert(oopDesc::is_oop(obj, true), "Not an oop at " PTR_FORMAT, p2i(cur));
394     assert(obj->klass_or_null() != NULL,
395            "Unparsable heap at " PTR_FORMAT, p2i(cur));
396 
397     size_t size;
398     bool is_dead = is_obj_dead_with_size(obj, bitmap, &size);
399     bool is_precise = false;
400 
401     cur += size;
402     if (!is_dead) {
403       // Process live object's references.
404 
405       // Non-objArrays are usually marked imprecise at the object
406       // start, in which case we need to iterate over them in full.
407       // objArrays are precisely marked, but can still be iterated
408       // over in full if completely covered.
409       if (!obj->is_objArray() || (cast_from_oop<HeapWord*>(obj) >= start && cur <= end)) {
410         obj->oop_iterate(cl);
411       } else {
412         obj->oop_iterate(cl, mr);
413         is_precise = true;
414       }
415     }
416     if (cur >= end) {
417       return is_precise ? end : cur;
418     }
419   }
420 }
421 
422 inline int HeapRegion::age_in_surv_rate_group() const {
423   assert(has_surv_rate_group(), "pre-condition");
424   assert(has_valid_age_in_surv_rate(), "pre-condition");
425   return _surv_rate_group->age_in_group(_age_index);
426 }
427 
428 inline bool HeapRegion::has_valid_age_in_surv_rate() const {
429   return G1SurvRateGroup::is_valid_age_index(_age_index);
430 }
431 
432 inline bool HeapRegion::has_surv_rate_group() const {
433   return _surv_rate_group != NULL;
434 }
435 
436 inline double HeapRegion::surv_rate_prediction(G1Predictions const& predictor) const {
437   assert(has_surv_rate_group(), "pre-condition");
438   return _surv_rate_group->surv_rate_pred(predictor, age_in_surv_rate_group());
439 }
440 
441 inline void HeapRegion::install_surv_rate_group(G1SurvRateGroup* surv_rate_group) {
442   assert(surv_rate_group != NULL, "pre-condition");
443   assert(!has_surv_rate_group(), "pre-condition");
444   assert(is_young(), "pre-condition");
445 
446   _surv_rate_group = surv_rate_group;
447   _age_index = surv_rate_group->next_age_index();
448 }
449 
450 inline void HeapRegion::uninstall_surv_rate_group() {
451   if (has_surv_rate_group()) {
452     assert(has_valid_age_in_surv_rate(), "pre-condition");
453     assert(is_young(), "pre-condition");
454 
455     _surv_rate_group = NULL;
456     _age_index = G1SurvRateGroup::InvalidAgeIndex;
457   } else {
458     assert(!has_valid_age_in_surv_rate(), "pre-condition");
459   }
460 }
461 
462 inline void HeapRegion::record_surv_words_in_group(size_t words_survived) {
463   assert(has_surv_rate_group(), "pre-condition");
464   assert(has_valid_age_in_surv_rate(), "pre-condition");
465   int age_in_group = age_in_surv_rate_group();
466   _surv_rate_group->record_surviving_words(age_in_group, words_survived);
467 }
468 
469 #endif // SHARE_GC_G1_HEAPREGION_INLINE_HPP
--- EOF ---