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. 22 * 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 scan count, also sweep ID. 35 static nmethod* _current; // Current nmethod 36 static int _seen; // Nof. nmethod we have currently processed in current pass of CodeCache 37 static int _flushed_count; // Nof. nmethods flushed in current sweep 38 static int _zombified_count; // Nof. nmethods made zombie in current sweep 39 static int _marked_count; // Nof. nmethods marked for reclaim in current sweep 40 41 static volatile int _invocations; // No. of invocations left until we are completed with this pass 42 static volatile int _sweep_started; // Flag to control conc sweeper 43 44 static bool _rescan; // Indicates that we should do a full rescan of the 45 // of the code cache looking for work to do. 46 static bool _do_sweep; // Flag to skip the conc sweep if no stack scan happened 47 static int _locked_seen; // Number of locked nmethods encountered during the scan 48 static int _not_entrant_seen_on_stack; // Number of not entrant nmethod were are still on stack 49 50 static bool _was_full; // remember if we did emergency unloading 51 static jint _advise_to_sweep; // flag to indicate code cache getting full 52 static jlong _last_was_full; // timestamp of last emergency unloading 53 static uint _highest_marked; // highest compile id dumped at last emergency unloading 54 static long _was_full_traversal; // trav number at last emergency unloading 55 56 // Stat counters 57 static int _number_of_flushes; // Total of full traversals caused by full cache 58 static int _total_nof_methods_reclaimed; // Accumulated nof methods flushed 59 static jlong _total_time_sweeping; // Accumulated time sweeping 60 static jlong _total_time_this_sweep; // Total time this sweep 61 static jlong _peak_sweep_time; // Peak time for a full sweep 62 static jlong _peak_sweep_fraction_time; // Peak time sweeping one fraction 63 static jlong _total_disconnect_time; // Total time cleaning code mem 64 static jlong _peak_disconnect_time; // Peak time cleaning code mem 65 66 static void process_nmethod(nmethod *nm); 67 68 static void log_sweep(const char* msg, const char* format = NULL, ...); 69 70 public: 71 static long traversal_count() { return _traversals; } 72 static int number_of_flushes() { return _number_of_flushes; } 73 static int total_nof_methods_reclaimed() { return _total_nof_methods_reclaimed; } 74 static jlong total_time_sweeping() { return _total_time_sweeping; } 75 static jlong peak_sweep_time() { return _peak_sweep_time; } 76 static jlong peak_sweep_fraction_time() { return _peak_sweep_fraction_time; } 77 static jlong total_disconnect_time() { return _total_disconnect_time; } 78 static jlong peak_disconnect_time() { return _peak_disconnect_time; } 79 80 #ifdef ASSERT 81 // Keep track of sweeper activity in the ring buffer 82 static void record_sweep(nmethod* nm, int line); 83 static void report_events(int id, address entry); 84 static void report_events(); 85 #endif 86 87 static void scan_stacks(); // Invoked at the end of each safepoint 88 static void sweep_code_cache(); // Concurrent part of sweep job 89 static void possibly_sweep(); // Compiler threads call this to sweep 90 91 static void notify(nmethod* nm) { 92 // Perform a full scan of the code cache from the beginning. No 93 // need to synchronize the setting of this flag since it only 94 // changes to false at safepoint so we can never overwrite it with false. 95 _rescan = true; 96 } 97 98 static void handle_full_code_cache(bool is_full); // Called by compilers who fail to allocate 99 static void speculative_disconnect_nmethods(bool was_full); // Called by vm op to deal with alloc failure 100 101 static void set_was_full(bool state) { _was_full = state; } 102 static bool was_full() { return _was_full; } 103 }; 104 105 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP