1 /*
2 * Copyright (c) 1997, 2010, 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.
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23 */
24
25 #ifndef SHARE_VM_RUNTIME_SWEEPER_HPP
26 #define SHARE_VM_RUNTIME_SWEEPER_HPP
27
28 // An NmethodSweeper is an incremental cleaner for:
29 // - cleanup inline caches
30 // - reclamation of unreferences zombie nmethods
31 //
32
33 class NMethodSweeper : public AllStatic {
34 static long _traversals; // Stack traversal count
35 static int _seen; // Nof. nmethod we have currently processed in current pass of CodeCache
36 static int _invocations; // No. of invocations of the sweeper
37
38 static volatile int _sweep_started; // Flag to control conc sweeper
39 static volatile nmethod* _current; // Current nmethod
40
41 static bool _rescan; // Indicates that we should do a full rescan of the
42 // of the code cache looking for work to do.
43 static bool _do_sweep; // Flag to skip the conc sweep if no stack scan happened
44 static int _locked_seen; // Number of locked nmethods encountered during the scan
45 static int _not_entrant_seen_on_stack; // Number of not entrant nmethod were are still on stack
46
47 static bool _was_full; // remember if we did emergency unloading
48 static jint _advise_to_sweep; // flag to indicate code cache getting full
49 static jlong _last_was_full; // timestamp of last emergency unloading
50 static uint _highest_marked; // highest compile id dumped at last emergency unloading
51 static long _was_full_traversal; // trav number at last emergency unloading
52
53 static void process_nmethod(nmethod *nm);
54
55 static void log_sweep(const char* msg, const char* format = NULL, ...);
56
57 public:
58 static long traversal_count() { return _traversals; }
59
60 #ifdef ASSERT
61 // Keep track of sweeper activity in the ring buffer
62 static void record_sweep(nmethod* nm, int line);
63 static void report_events(int id, address entry);
64 static void report_events();
65 #endif
66
67 static void scan_stacks(); // Invoked at the end of each safepoint
68 static void sweep_code_cache(); // Concurrent part of sweep job
69 static void possibly_sweep(); // Compiler threads call this to sweep
70
71 static void notify(nmethod* nm) {
72 // Perform a full scan of the code cache from the beginning. No
73 // need to synchronize the setting of this flag since it only
74 // changes to false at safepoint so we can never overwrite it with false.
75 _rescan = true;
76 }
77
78 static void handle_full_code_cache(bool is_full); // Called by compilers who fail to allocate
79 static void speculative_disconnect_nmethods(bool was_full); // Called by vm op to deal with alloc failure
80
81 static void set_was_full(bool state) { _was_full = state; }
82 static bool was_full() { return _was_full; }
83 };
84
85 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP