Tue, 19 Aug 2014 02:05:49 -0700
8044406: JVM crash with JDK8 (build 1.8.0-b132) with G1 GC
Summary: Fill the last card that has been allocated into with a dummy object
Reviewed-by: tschatzl, mgerdin
1 /*
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13 * accompanied this code).
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
28 #include "gc_implementation/g1/ptrQueue.hpp"
30 class ObjectClosure;
31 class JavaThread;
32 class SATBMarkQueueSet;
34 // A ptrQueue whose elements are "oops", pointers to object heads.
35 class ObjPtrQueue: public PtrQueue {
36 friend class SATBMarkQueueSet;
38 private:
39 // Filter out unwanted entries from the buffer.
40 void filter();
42 // Apply the closure to all elements.
43 void apply_closure(ObjectClosure* cl);
45 // Apply the closure to all elements and empty the buffer;
46 void apply_closure_and_empty(ObjectClosure* cl);
48 // Apply the closure to all elements of "buf", down to "index" (inclusive.)
49 static void apply_closure_to_buffer(ObjectClosure* cl,
50 void** buf, size_t index, size_t sz);
52 public:
53 ObjPtrQueue(PtrQueueSet* qset, bool perm = false) :
54 // SATB queues are only active during marking cycles. We create
55 // them with their active field set to false. If a thread is
56 // created during a cycle and its SATB queue needs to be activated
57 // before the thread starts running, we'll need to set its active
58 // field to true. This is done in JavaThread::initialize_queues().
59 PtrQueue(qset, perm, false /* active */) { }
61 // Process queue entries and free resources.
62 void flush();
64 // Overrides PtrQueue::should_enqueue_buffer(). See the method's
65 // definition for more information.
66 virtual bool should_enqueue_buffer();
68 #ifndef PRODUCT
69 // Helpful for debugging
70 void print(const char* name);
71 static void print(const char* name, void** buf, size_t index, size_t sz);
72 #endif // PRODUCT
74 void verify_oops_in_buffer() NOT_DEBUG_RETURN;
75 };
77 class SATBMarkQueueSet: public PtrQueueSet {
78 ObjectClosure* _closure;
79 ObjectClosure** _par_closures; // One per ParGCThread.
81 ObjPtrQueue _shared_satb_queue;
83 // Utility function to support sequential and parallel versions. If
84 // "par" is true, then "worker" is the par thread id; if "false", worker
85 // is ignored.
86 bool apply_closure_to_completed_buffer_work(bool par, uint worker);
88 #ifdef ASSERT
89 void dump_active_states(bool expected_active);
90 void verify_active_states(bool expected_active);
91 #endif // ASSERT
93 public:
94 SATBMarkQueueSet();
96 void initialize(Monitor* cbl_mon, Mutex* fl_lock,
97 int process_completed_threshold,
98 Mutex* lock);
100 static void handle_zero_index_for_thread(JavaThread* t);
102 // Apply "set_active(active)" to all SATB queues in the set. It should be
103 // called only with the world stopped. The method will assert that the
104 // SATB queues of all threads it visits, as well as the SATB queue
105 // set itself, has an active value same as expected_active.
106 void set_active_all_threads(bool active, bool expected_active);
108 // Filter all the currently-active SATB buffers.
109 void filter_thread_buffers();
111 // Register "blk" as "the closure" for all queues. Only one such closure
112 // is allowed. The "apply_closure_to_completed_buffer" method will apply
113 // this closure to a completed buffer, and "iterate_closure_all_threads"
114 // applies it to partially-filled buffers (the latter should only be done
115 // with the world stopped).
116 void set_closure(ObjectClosure* closure);
117 // Set the parallel closures: pointer is an array of pointers to
118 // closures, one for each parallel GC thread.
119 void set_par_closure(int i, ObjectClosure* closure);
121 // Apply the registered closure to all entries on each
122 // currently-active buffer and then empty the buffer. It should only
123 // be called serially and at a safepoint.
124 void iterate_closure_all_threads();
125 // Parallel version of the above.
126 void par_iterate_closure_all_threads(uint worker);
128 // If there exists some completed buffer, pop it, then apply the
129 // registered closure to all its elements, and return true. If no
130 // completed buffers exist, return false.
131 bool apply_closure_to_completed_buffer() {
132 return apply_closure_to_completed_buffer_work(false, 0);
133 }
134 // Parallel version of the above.
135 bool par_apply_closure_to_completed_buffer(uint worker) {
136 return apply_closure_to_completed_buffer_work(true, worker);
137 }
139 // Apply the given closure on enqueued and currently-active buffers
140 // respectively. Both methods are read-only, i.e., they do not
141 // modify any of the buffers.
142 void iterate_completed_buffers_read_only(ObjectClosure* cl);
143 void iterate_thread_buffers_read_only(ObjectClosure* cl);
145 #ifndef PRODUCT
146 // Helpful for debugging
147 void print_all(const char* msg);
148 #endif // PRODUCT
150 ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
152 // If a marking is being abandoned, reset any unprocessed log buffers.
153 void abandon_partial_marking();
154 };
156 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP