1 /*
2 * Copyright (c) 1997, 2016, 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_RUNTIME_SWEEPER_HPP
26 #define SHARE_VM_RUNTIME_SWEEPER_HPP
27
28 class WhiteBox;
29
30 #include "code/codeCache.hpp"
31 #include "utilities/ticks.hpp"
32
33 // An NmethodSweeper is an incremental cleaner for:
34 // - cleanup inline caches
35 // - reclamation of nmethods
36 // Removing nmethods from the code cache includes two operations
37 // 1) mark active nmethods
38 // Is done in 'mark_active_nmethods()'. This function is called at a
39 // safepoint and marks all nmethods that are active on a thread's stack.
40 // 2) sweep nmethods
41 // Is done in sweep_code_cache(). This function is the only place in the
42 // sweeper where memory is reclaimed. Note that sweep_code_cache() is not
43 // called at a safepoint. However, sweep_code_cache() stops executing if
44 // another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
45 // and sweep_code_cache() cannot execute at the same time.
46 // To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
47 // be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
48 // invalidation, and (iv) being replaced by a different method version (tiered
49 // compilation). Not-entrant nmethods cannot be called by Java threads, but they
50 // can still be active on the stack. To ensure that active nmethods are not reclaimed,
51 // we have to wait until the next marking phase has completed. If a not-entrant
52 // nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely
97 static void handle_safepoint_request();
98 static void do_stack_scanning();
99 static void possibly_sweep();
100 public:
101 static long traversal_count() { return _traversals; }
102 static int total_nof_methods_reclaimed() { return _total_nof_methods_reclaimed; }
103 static const Tickspan total_time_sweeping() { return _total_time_sweeping; }
104 static const Tickspan peak_sweep_time() { return _peak_sweep_time; }
105 static const Tickspan peak_sweep_fraction_time() { return _peak_sweep_fraction_time; }
106 static void log_sweep(const char* msg, const char* format = NULL, ...) ATTRIBUTE_PRINTF(2, 3);
107
108
109 #ifdef ASSERT
110 // Keep track of sweeper activity in the ring buffer
111 static void record_sweep(CompiledMethod* nm, int line);
112 static void report_events(int id, address entry);
113 static void report_events();
114 #endif
115
116 static void mark_active_nmethods(); // Invoked at the end of each safepoint
117 static void sweeper_loop();
118 static void notify(int code_blob_type); // Possibly start the sweeper thread.
119 static void force_sweep();
120
121 static int hotness_counter_reset_val();
122 static void report_state_change(nmethod* nm);
123 static void possibly_enable_sweeper();
124 static void possibly_flush(nmethod* nm);
125 static void print(); // Printing/debugging
126 };
127
128 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP
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1 /*
2 * Copyright (c) 1997, 2017, 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_RUNTIME_SWEEPER_HPP
26 #define SHARE_VM_RUNTIME_SWEEPER_HPP
27
28 class WhiteBox;
29
30 #include "code/codeCache.hpp"
31 #include "utilities/ticks.hpp"
32
33 class CodeBlobClosure;
34
35 // An NmethodSweeper is an incremental cleaner for:
36 // - cleanup inline caches
37 // - reclamation of nmethods
38 // Removing nmethods from the code cache includes two operations
39 // 1) mark active nmethods
40 // Is done in 'mark_active_nmethods()'. This function is called at a
41 // safepoint and marks all nmethods that are active on a thread's stack.
42 // 2) sweep nmethods
43 // Is done in sweep_code_cache(). This function is the only place in the
44 // sweeper where memory is reclaimed. Note that sweep_code_cache() is not
45 // called at a safepoint. However, sweep_code_cache() stops executing if
46 // another thread requests a safepoint. Consequently, 'mark_active_nmethods()'
47 // and sweep_code_cache() cannot execute at the same time.
48 // To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can
49 // be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency
50 // invalidation, and (iv) being replaced by a different method version (tiered
51 // compilation). Not-entrant nmethods cannot be called by Java threads, but they
52 // can still be active on the stack. To ensure that active nmethods are not reclaimed,
53 // we have to wait until the next marking phase has completed. If a not-entrant
54 // nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely
99 static void handle_safepoint_request();
100 static void do_stack_scanning();
101 static void possibly_sweep();
102 public:
103 static long traversal_count() { return _traversals; }
104 static int total_nof_methods_reclaimed() { return _total_nof_methods_reclaimed; }
105 static const Tickspan total_time_sweeping() { return _total_time_sweeping; }
106 static const Tickspan peak_sweep_time() { return _peak_sweep_time; }
107 static const Tickspan peak_sweep_fraction_time() { return _peak_sweep_fraction_time; }
108 static void log_sweep(const char* msg, const char* format = NULL, ...) ATTRIBUTE_PRINTF(2, 3);
109
110
111 #ifdef ASSERT
112 // Keep track of sweeper activity in the ring buffer
113 static void record_sweep(CompiledMethod* nm, int line);
114 static void report_events(int id, address entry);
115 static void report_events();
116 #endif
117
118 static void mark_active_nmethods(); // Invoked at the end of each safepoint
119 static CodeBlobClosure* prepare_mark_active_nmethods();
120 static void sweeper_loop();
121 static void notify(int code_blob_type); // Possibly start the sweeper thread.
122 static void force_sweep();
123
124 static int hotness_counter_reset_val();
125 static void report_state_change(nmethod* nm);
126 static void possibly_enable_sweeper();
127 static void possibly_flush(nmethod* nm);
128 static void print(); // Printing/debugging
129 };
130
131 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP
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