Tue, 08 Oct 2013 17:35:51 +0200
8014555: G1: Memory ordering problem with Conc refinement and card marking
Summary: Add a StoreLoad barrier in the G1 post-barrier to fix a race with concurrent refinement. Also-reviewed-by: martin.doerr@sap.com
Reviewed-by: iveresov, tschatzl, brutisso, roland, kvn
1 /*
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP
28 #include "gc_implementation/g1/concurrentMark.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.hpp"
30 #include "gc_implementation/g1/g1AllocRegion.inline.hpp"
31 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
32 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
33 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
34 #include "utilities/taskqueue.hpp"
36 // Inline functions for G1CollectedHeap
38 template <class T>
39 inline HeapRegion*
40 G1CollectedHeap::heap_region_containing(const T addr) const {
41 HeapRegion* hr = _hrs.addr_to_region((HeapWord*) addr);
42 // hr can be null if addr in perm_gen
43 if (hr != NULL && hr->continuesHumongous()) {
44 hr = hr->humongous_start_region();
45 }
46 return hr;
47 }
49 template <class T>
50 inline HeapRegion*
51 G1CollectedHeap::heap_region_containing_raw(const T addr) const {
52 assert(_g1_reserved.contains((const void*) addr), "invariant");
53 HeapRegion* res = _hrs.addr_to_region_unsafe((HeapWord*) addr);
54 return res;
55 }
57 inline bool G1CollectedHeap::obj_in_cs(oop obj) {
58 HeapRegion* r = _hrs.addr_to_region((HeapWord*) obj);
59 return r != NULL && r->in_collection_set();
60 }
62 inline HeapWord*
63 G1CollectedHeap::attempt_allocation(size_t word_size,
64 unsigned int* gc_count_before_ret,
65 int* gclocker_retry_count_ret) {
66 assert_heap_not_locked_and_not_at_safepoint();
67 assert(!isHumongous(word_size), "attempt_allocation() should not "
68 "be called for humongous allocation requests");
70 HeapWord* result = _mutator_alloc_region.attempt_allocation(word_size,
71 false /* bot_updates */);
72 if (result == NULL) {
73 result = attempt_allocation_slow(word_size,
74 gc_count_before_ret,
75 gclocker_retry_count_ret);
76 }
77 assert_heap_not_locked();
78 if (result != NULL) {
79 dirty_young_block(result, word_size);
80 }
81 return result;
82 }
84 inline HeapWord* G1CollectedHeap::survivor_attempt_allocation(size_t
85 word_size) {
86 assert(!isHumongous(word_size),
87 "we should not be seeing humongous-size allocations in this path");
89 HeapWord* result = _survivor_gc_alloc_region.attempt_allocation(word_size,
90 false /* bot_updates */);
91 if (result == NULL) {
92 MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
93 result = _survivor_gc_alloc_region.attempt_allocation_locked(word_size,
94 false /* bot_updates */);
95 }
96 if (result != NULL) {
97 dirty_young_block(result, word_size);
98 }
99 return result;
100 }
102 inline HeapWord* G1CollectedHeap::old_attempt_allocation(size_t word_size) {
103 assert(!isHumongous(word_size),
104 "we should not be seeing humongous-size allocations in this path");
106 HeapWord* result = _old_gc_alloc_region.attempt_allocation(word_size,
107 true /* bot_updates */);
108 if (result == NULL) {
109 MutexLockerEx x(FreeList_lock, Mutex::_no_safepoint_check_flag);
110 result = _old_gc_alloc_region.attempt_allocation_locked(word_size,
111 true /* bot_updates */);
112 }
113 return result;
114 }
116 // It dirties the cards that cover the block so that so that the post
117 // write barrier never queues anything when updating objects on this
118 // block. It is assumed (and in fact we assert) that the block
119 // belongs to a young region.
120 inline void
121 G1CollectedHeap::dirty_young_block(HeapWord* start, size_t word_size) {
122 assert_heap_not_locked();
124 // Assign the containing region to containing_hr so that we don't
125 // have to keep calling heap_region_containing_raw() in the
126 // asserts below.
127 DEBUG_ONLY(HeapRegion* containing_hr = heap_region_containing_raw(start);)
128 assert(containing_hr != NULL && start != NULL && word_size > 0,
129 "pre-condition");
130 assert(containing_hr->is_in(start), "it should contain start");
131 assert(containing_hr->is_young(), "it should be young");
132 assert(!containing_hr->isHumongous(), "it should not be humongous");
134 HeapWord* end = start + word_size;
135 assert(containing_hr->is_in(end - 1), "it should also contain end - 1");
137 MemRegion mr(start, end);
138 g1_barrier_set()->g1_mark_as_young(mr);
139 }
141 inline RefToScanQueue* G1CollectedHeap::task_queue(int i) const {
142 return _task_queues->queue(i);
143 }
145 inline bool G1CollectedHeap::isMarkedPrev(oop obj) const {
146 return _cm->prevMarkBitMap()->isMarked((HeapWord *)obj);
147 }
149 inline bool G1CollectedHeap::isMarkedNext(oop obj) const {
150 return _cm->nextMarkBitMap()->isMarked((HeapWord *)obj);
151 }
153 #ifndef PRODUCT
154 // Support for G1EvacuationFailureALot
156 inline bool
157 G1CollectedHeap::evacuation_failure_alot_for_gc_type(bool gcs_are_young,
158 bool during_initial_mark,
159 bool during_marking) {
160 bool res = false;
161 if (during_marking) {
162 res |= G1EvacuationFailureALotDuringConcMark;
163 }
164 if (during_initial_mark) {
165 res |= G1EvacuationFailureALotDuringInitialMark;
166 }
167 if (gcs_are_young) {
168 res |= G1EvacuationFailureALotDuringYoungGC;
169 } else {
170 // GCs are mixed
171 res |= G1EvacuationFailureALotDuringMixedGC;
172 }
173 return res;
174 }
176 inline void
177 G1CollectedHeap::set_evacuation_failure_alot_for_current_gc() {
178 if (G1EvacuationFailureALot) {
179 // Note we can't assert that _evacuation_failure_alot_for_current_gc
180 // is clear here. It may have been set during a previous GC but that GC
181 // did not copy enough objects (i.e. G1EvacuationFailureALotCount) to
182 // trigger an evacuation failure and clear the flags and and counts.
184 // Check if we have gone over the interval.
185 const size_t gc_num = total_collections();
186 const size_t elapsed_gcs = gc_num - _evacuation_failure_alot_gc_number;
188 _evacuation_failure_alot_for_current_gc = (elapsed_gcs >= G1EvacuationFailureALotInterval);
190 // Now check if G1EvacuationFailureALot is enabled for the current GC type.
191 const bool gcs_are_young = g1_policy()->gcs_are_young();
192 const bool during_im = g1_policy()->during_initial_mark_pause();
193 const bool during_marking = mark_in_progress();
195 _evacuation_failure_alot_for_current_gc &=
196 evacuation_failure_alot_for_gc_type(gcs_are_young,
197 during_im,
198 during_marking);
199 }
200 }
202 inline bool
203 G1CollectedHeap::evacuation_should_fail() {
204 if (!G1EvacuationFailureALot || !_evacuation_failure_alot_for_current_gc) {
205 return false;
206 }
207 // G1EvacuationFailureALot is in effect for current GC
208 // Access to _evacuation_failure_alot_count is not atomic;
209 // the value does not have to be exact.
210 if (++_evacuation_failure_alot_count < G1EvacuationFailureALotCount) {
211 return false;
212 }
213 _evacuation_failure_alot_count = 0;
214 return true;
215 }
217 inline void G1CollectedHeap::reset_evacuation_should_fail() {
218 if (G1EvacuationFailureALot) {
219 _evacuation_failure_alot_gc_number = total_collections();
220 _evacuation_failure_alot_count = 0;
221 _evacuation_failure_alot_for_current_gc = false;
222 }
223 }
224 #endif // #ifndef PRODUCT
226 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP