1 /*
2  * Copyright (c) 2001, 2019, 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_SHENANDOAH_SATBMARKQUEUE_HPP
26 #define SHARE_VM_GC_SHENANDOAH_SATBMARKQUEUE_HPP
27 
28 #include "gc/g1/ptrQueue.hpp"
29 #include "memory/allocation.hpp"
30 
31 class JavaThread;
32 class ShenandoahSATBMarkQueueSet;
33 
34 // Base class for processing the contents of a SATB buffer.
35 class ShenandoahSATBBufferClosure : public StackObj {
36 protected:
~ShenandoahSATBBufferClosure()37   ~ShenandoahSATBBufferClosure() { }
38 
39 public:
40   // Process the SATB entries in the designated buffer range.
41   virtual void do_buffer(void** buffer, size_t size) = 0;
42 };
43 
44 // A PtrQueue whose elements are (possibly stale) pointers to object heads.
45 class ShenandoahSATBMarkQueue: public PtrQueue {
46   friend class ShenandoahSATBMarkQueueSet;
47 
48 private:
49   // Filter out unwanted entries from the buffer.
50   void filter();
51 
52   template <class HeapType>
53   void filter_impl();
54 
55 public:
56   ShenandoahSATBMarkQueue(ShenandoahSATBMarkQueueSet* qset, bool permanent = false);
57 
58   // Process queue entries and free resources.
59   void flush();
60 
61   // Apply cl to the active part of the buffer.
62   // Prerequisite: Must be at a safepoint.
63   void apply_closure_and_empty(ShenandoahSATBBufferClosure* cl);
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 #endif // PRODUCT
73 
74   // Compiler support.
byte_offset_of_index()75   static ByteSize byte_offset_of_index() {
76     return PtrQueue::byte_offset_of_index<ShenandoahSATBMarkQueue>();
77   }
78   using PtrQueue::byte_width_of_index;
79 
byte_offset_of_buf()80   static ByteSize byte_offset_of_buf() {
81     return PtrQueue::byte_offset_of_buf<ShenandoahSATBMarkQueue>();
82   }
83   using PtrQueue::byte_width_of_buf;
84 
byte_offset_of_active()85   static ByteSize byte_offset_of_active() {
86     return PtrQueue::byte_offset_of_active<ShenandoahSATBMarkQueue>();
87   }
88   using PtrQueue::byte_width_of_active;
89 
90 };
91 
92 class ShenandoahSATBMarkQueueSet: public PtrQueueSet {
93   ShenandoahSATBMarkQueue _shared_satb_queue;
94 
95 #ifdef ASSERT
96   void dump_active_states(bool expected_active);
97   void verify_active_states(bool expected_active);
98 #endif // ASSERT
99 
100 public:
101   ShenandoahSATBMarkQueueSet();
102 
103   void initialize(Monitor* cbl_mon, Mutex* fl_lock,
104                   int process_completed_threshold,
105                   Mutex* lock);
106 
107   ShenandoahSATBMarkQueue& satb_queue_for_thread(Thread* t);
108 
109   // Apply "set_active(active)" to all SATB queues in the set. It should be
110   // called only with the world stopped. The method will assert that the
111   // SATB queues of all threads it visits, as well as the SATB queue
112   // set itself, has an active value same as expected_active.
113   void set_active_all_threads(bool active, bool expected_active);
114 
115   // Filter all the currently-active SATB buffers.
116   void filter_thread_buffers();
117 
118   // If there exists some completed buffer, pop and process it, and
119   // return true.  Otherwise return false.  Processing a buffer
120   // consists of applying the closure to the active range of the
121   // buffer; the leading entries may be excluded due to filtering.
122   bool apply_closure_to_completed_buffer(ShenandoahSATBBufferClosure* cl);
123 
124 #ifndef PRODUCT
125   // Helpful for debugging
126   void print_all(const char* msg);
127 #endif // PRODUCT
128 
shared_satb_queue()129   ShenandoahSATBMarkQueue* shared_satb_queue() { return &_shared_satb_queue; }
130 
131   // If a marking is being abandoned, reset any unprocessed log buffers.
132   void abandon_partial_marking();
133 };
134 
135 #endif // SHARE_VM_GC_SHENANDOAH_SATBMARKQUEUE_HPP
136