1 /* 2 * Copyright (c) 1997, 2013, 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 //The following are reset in scan_stacks and synchronized by the safepoint 45 static bool _resweep; // Indicates that a change has happend and we want another sweep, 46 // always checked and reset at a safepoint so memory will be in sync. 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 static jint _flush_token; // token that guards method flushing, making sure it is executed only once. 50 51 // These are set during a flush, a VM-operation 52 static long _last_flush_traversal_id; // trav number at last flush unloading 53 static jlong _last_full_flush_time; // timestamp of last emergency unloading 54 55 // These are synchronized by the _sweep_started token 56 static int _highest_marked; // highest compile id dumped at last emergency unloading 57 static int _dead_compile_ids; // number of compile ids that where not in the cache last flush 58 59 // Stat counters 60 static int _number_of_flushes; // Total of full traversals caused by full cache 61 static int _total_nof_methods_reclaimed; // Accumulated nof methods flushed 62 static jlong _total_time_sweeping; // Accumulated time sweeping 63 static jlong _total_time_this_sweep; // Total time this sweep 64 static jlong _peak_sweep_time; // Peak time for a full sweep 65 static jlong _peak_sweep_fraction_time; // Peak time sweeping one fraction 66 static jlong _total_disconnect_time; // Total time cleaning code mem 67 static jlong _peak_disconnect_time; // Peak time cleaning code mem 68 69 static void process_nmethod(nmethod *nm); 70 static void release_nmethod(nmethod* nm); 71 72 static void log_sweep(const char* msg, const char* format = NULL, ...); 73 static bool sweep_in_progress(); 74 75 public: 76 static long traversal_count() { return _traversals; } 77 static int number_of_flushes() { return _number_of_flushes; } 78 static int total_nof_methods_reclaimed() { return _total_nof_methods_reclaimed; } 79 static jlong total_time_sweeping() { return _total_time_sweeping; } 80 static jlong peak_sweep_time() { return _peak_sweep_time; } 81 static jlong peak_sweep_fraction_time() { return _peak_sweep_fraction_time; } 82 static jlong total_disconnect_time() { return _total_disconnect_time; } 83 static jlong peak_disconnect_time() { return _peak_disconnect_time; } 84 85 #ifdef ASSERT 86 // Keep track of sweeper activity in the ring buffer 87 static void record_sweep(nmethod* nm, int line); 88 static void report_events(int id, address entry); 89 static void report_events(); 90 #endif 91 92 static void scan_stacks(); // Invoked at the end of each safepoint 93 static void sweep_code_cache(); // Concurrent part of sweep job 94 static void possibly_sweep(); // Compiler threads call this to sweep 95 96 static void notify(nmethod* nm) { 97 // Request a new sweep of the code cache from the beginning. No 98 // need to synchronize the setting of this flag since it only 99 // changes to false at safepoint so we can never overwrite it with false. 100 _resweep = true; 101 } 102 103 static void handle_full_code_cache(bool is_full); // Called by compilers who fail to allocate 104 static void speculative_disconnect_nmethods(bool was_full); // Called by vm op to deal with alloc failure 105 }; 106 107 #endif // SHARE_VM_RUNTIME_SWEEPER_HPP