1 /*
2 * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP
27
28 #include "gc_implementation/g1/ptrQueue.hpp"
29
30 class ObjectClosure;
31 class JavaThread;
32 class SATBMarkQueueSet;
33
34 // A ptrQueue whose elements are "oops", pointers to object heads.
35 class ObjPtrQueue: public PtrQueue {
36 friend class SATBMarkQueueSet;
37
38 private:
39 // Filter out unwanted entries from the buffer.
40 void filter();
41
42 // Apply the closure to all elements.
43 void apply_closure(ObjectClosure* cl);
44
45 // Apply the closure to all elements and empty the buffer;
46 void apply_closure_and_empty(ObjectClosure* cl);
47
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);
51
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 */) { }
60
61 // Overrides PtrQueue::flush() so that it can filter the buffer
62 // before it is flushed.
63 virtual void flush();
64
65 // Overrides PtrQueue::should_enqueue_buffer(). See the method's
66 // definition for more information.
67 virtual bool should_enqueue_buffer();
68
69 #ifndef PRODUCT
70 // Helpful for debugging
71 void print(const char* name);
72 static void print(const char* name, void** buf, size_t index, size_t sz);
73 #endif // PRODUCT
74
75 void verify_oops_in_buffer() NOT_DEBUG_RETURN;
76 };
77
78 class SATBMarkQueueSet: public PtrQueueSet {
79 ObjectClosure* _closure;
80 ObjectClosure** _par_closures; // One per ParGCThread.
81
82 ObjPtrQueue _shared_satb_queue;
83
84 // Utility function to support sequential and parallel versions. If
85 // "par" is true, then "worker" is the par thread id; if "false", worker
86 // is ignored.
87 bool apply_closure_to_completed_buffer_work(bool par, uint worker);
88
89 #ifdef ASSERT
90 void dump_active_states(bool expected_active);
91 void verify_active_states(bool expected_active);
92 #endif // ASSERT
93
94 public:
95 SATBMarkQueueSet();
96
97 void initialize(Monitor* cbl_mon, Mutex* fl_lock,
98 int process_completed_threshold,
99 Mutex* lock);
100
101 static void handle_zero_index_for_thread(JavaThread* t);
102
103 // Apply "set_active(active)" to all SATB queues in the set. It should be
104 // called only with the world stopped. The method will assert that the
105 // SATB queues of all threads it visits, as well as the SATB queue
106 // set itself, has an active value same as expected_active.
107 void set_active_all_threads(bool active, bool expected_active);
108
109 // Filter all the currently-active SATB buffers.
110 void filter_thread_buffers();
111
112 // Register "blk" as "the closure" for all queues. Only one such closure
113 // is allowed. The "apply_closure_to_completed_buffer" method will apply
114 // this closure to a completed buffer, and "iterate_closure_all_threads"
115 // applies it to partially-filled buffers (the latter should only be done
116 // with the world stopped).
117 void set_closure(ObjectClosure* closure);
118 // Set the parallel closures: pointer is an array of pointers to
119 // closures, one for each parallel GC thread.
120 void set_par_closure(int i, ObjectClosure* closure);
121
122 // Apply the registered closure to all entries on each
123 // currently-active buffer and then empty the buffer. It should only
124 // be called serially and at a safepoint.
125 void iterate_closure_all_threads();
126 // Parallel version of the above.
127 void par_iterate_closure_all_threads(uint worker);
128
129 // If there exists some completed buffer, pop it, then apply the
130 // registered closure to all its elements, and return true. If no
131 // completed buffers exist, return false.
132 bool apply_closure_to_completed_buffer() {
133 return apply_closure_to_completed_buffer_work(false, 0);
134 }
135 // Parallel version of the above.
136 bool par_apply_closure_to_completed_buffer(uint worker) {
137 return apply_closure_to_completed_buffer_work(true, worker);
138 }
139
140 // Apply the given closure on enqueued and currently-active buffers
141 // respectively. Both methods are read-only, i.e., they do not
142 // modify any of the buffers.
143 void iterate_completed_buffers_read_only(ObjectClosure* cl);
144 void iterate_thread_buffers_read_only(ObjectClosure* cl);
145
146 #ifndef PRODUCT
147 // Helpful for debugging
148 void print_all(const char* msg);
149 #endif // PRODUCT
150
151 ObjPtrQueue* shared_satb_queue() { return &_shared_satb_queue; }
152
153 // If a marking is being abandoned, reset any unprocessed log buffers.
154 void abandon_partial_marking();
155 };
156
157 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_SATBQUEUE_HPP