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.
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5 * This code is free software; you can redistribute it and/or modify it
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7 * published by the Free Software Foundation.
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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
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24
25#ifndef SHARE_GC_G1_G1CONCURRENTREFINE_HPP
26#define SHARE_GC_G1_G1CONCURRENTREFINE_HPP
27
28#include "memory/allocation.hpp"
29#include "utilities/globalDefinitions.hpp"
30
31// Forward decl
32class G1ConcurrentRefine;
33class G1ConcurrentRefineThread;
34class outputStream;
35class ThreadClosure;
36
37// Helper class for refinement thread management. Used to start, stop and
38// iterate over them.
39class G1ConcurrentRefineThreadControl {
40 G1ConcurrentRefine* _cr;
41
42 G1ConcurrentRefineThread** _threads;
43 uint _num_max_threads;
44
45 // Create the refinement thread for the given worker id.
46 // If initializing is true, ignore InjectGCWorkerCreationFailure.
47 G1ConcurrentRefineThread* create_refinement_thread(uint worker_id, bool initializing);
48public:
49 G1ConcurrentRefineThreadControl();
50 ~G1ConcurrentRefineThreadControl();
51
52 jint initialize(G1ConcurrentRefine* cr, uint num_max_threads);
53
54 // If there is a "successor" thread that can be activated given the current id,
55 // activate it.
56 void maybe_activate_next(uint cur_worker_id);
57
58 void print_on(outputStream* st) const;
59 void worker_threads_do(ThreadClosure* tc);
60 void stop();
61};
62
63// Controls refinement threads and their activation based on the number of completed
64// buffers currently available in the global dirty card queue.
65// Refinement threads pick work from the queue based on these thresholds. They are activated
66// gradually based on the amount of work to do.
67// Refinement thread n activates thread n+1 if the instance of this class determines there
68// is enough work available. Threads deactivate themselves if the current amount of
69// completed buffers falls below their individual threshold.
70class G1ConcurrentRefine : public CHeapObj<mtGC> {
71 G1ConcurrentRefineThreadControl _thread_control;
72 /*
73 * The value of the completed dirty card queue length falls into one of 3 zones:
74 * green, yellow, red. If the value is in [0, green) nothing is
75 * done, the buffers are left unprocessed to enable the caching effect of the
76 * dirtied cards. In the yellow zone [green, yellow) the concurrent refinement
77 * threads are gradually activated. In [yellow, red) all threads are
78 * running. If the length becomes red (max queue length) the mutators start
79 * processing the buffers.
80 *
81 * There are some interesting cases (when G1UseAdaptiveConcRefinement
82 * is turned off):
83 * 1) green = yellow = red = 0. In this case the mutator will process all
84 * buffers. Except for those that are created by the deferred updates
85 * machinery during a collection.
86 * 2) green = 0. Means no caching. Can be a good way to minimize the
87 * amount of time spent updating remembered sets during a collection.
88 */
89 size_t _green_zone;
90 size_t _yellow_zone;
91 size_t _red_zone;
92 size_t _min_yellow_zone_size;
93
94 G1ConcurrentRefine(size_t green_zone,
95 size_t yellow_zone,
96 size_t red_zone,
97 size_t min_yellow_zone_size);
98
99 // Update green/yellow/red zone values based on how well goals are being met.
100 void update_zones(double update_rs_time,
101 size_t update_rs_processed_buffers,
102 double goal_ms);
103
104 static uint worker_id_offset();
105 void maybe_activate_more_threads(uint worker_id, size_t num_cur_buffers);
106
107 jint initialize();
108public:
109 ~G1ConcurrentRefine();
110
111 // Returns a G1ConcurrentRefine instance if succeeded to create/initialize the
112 // G1ConcurrentRefine instance. Otherwise, returns NULL with error code.
113 static G1ConcurrentRefine* create(jint* ecode);
114
115 void stop();
116
117 // Adjust refinement thresholds based on work done during the pause and the goal time.
118 void adjust(double update_rs_time, size_t update_rs_processed_buffers, double goal_ms);
119
120 size_t activation_threshold(uint worker_id) const;
121 size_t deactivation_threshold(uint worker_id) const;
122 // Perform a single refinement step. Called by the refinement threads when woken up.
123 bool do_refinement_step(uint worker_id);
124
125 // Iterate over all concurrent refinement threads applying the given closure.
126 void threads_do(ThreadClosure *tc);
127
128 // Maximum number of refinement threads.
129 static uint max_num_threads();
130
131 void print_threads_on(outputStream* st) const;
132
133 size_t green_zone() const { return _green_zone; }
134 size_t yellow_zone() const { return _yellow_zone; }
135 size_t red_zone() const { return _red_zone; }
136};
137
138#endif // SHARE_GC_G1_G1CONCURRENTREFINE_HPP
139