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src/share/vm/runtime/sweeper.hpp@91ddc23482a4 (annotated)
src/share/vm/runtime/sweeper.hpp
Thu, 24 May 2018 20:03:11 +0800
- author
- aoqi
- date
- Thu, 24 May 2018 20:03:11 +0800
- changeset 8868
- 91ddc23482a4
- parent 6876
- 710a3c8b516e
- permissions
- -rw-r--r--
Increase MaxHeapSize for better performance on MIPS
| aoqi@0 | 1 | /* |
| aoqi@0 | 2 | * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. |
| aoqi@0 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| aoqi@0 | 4 | * |
| aoqi@0 | 5 | * This code is free software; you can redistribute it and/or modify it |
| aoqi@0 | 6 | * under the terms of the GNU General Public License version 2 only, as |
| aoqi@0 | 7 | * published by the Free Software Foundation. |
| aoqi@0 | 8 | * |
| aoqi@0 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
| aoqi@0 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| aoqi@0 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| aoqi@0 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
| aoqi@0 | 13 | * accompanied this code). |
| aoqi@0 | 14 | * |
| aoqi@0 | 15 | * You should have received a copy of the GNU General Public License version |
| aoqi@0 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
| aoqi@0 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| aoqi@0 | 18 | * |
| aoqi@0 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| aoqi@0 | 20 | * or visit www.oracle.com if you need additional information or have any |
| aoqi@0 | 21 | * questions. |
| aoqi@0 | 22 | * |
| aoqi@0 | 23 | */ |
| aoqi@0 | 24 | |
| aoqi@0 | 25 | #ifndef SHARE_VM_RUNTIME_SWEEPER_HPP |
| aoqi@0 | 26 | #define SHARE_VM_RUNTIME_SWEEPER_HPP |
| aoqi@0 | 27 | |
| aoqi@0 | 28 | #include "utilities/ticks.hpp" |
| aoqi@0 | 29 | // An NmethodSweeper is an incremental cleaner for: |
| aoqi@0 | 30 | // - cleanup inline caches |
| aoqi@0 | 31 | // - reclamation of nmethods |
| aoqi@0 | 32 | // Removing nmethods from the code cache includes two operations |
| aoqi@0 | 33 | // 1) mark active nmethods |
| aoqi@0 | 34 | // Is done in 'mark_active_nmethods()'. This function is called at a |
| aoqi@0 | 35 | // safepoint and marks all nmethods that are active on a thread's stack. |
| aoqi@0 | 36 | // 2) sweep nmethods |
| aoqi@0 | 37 | // Is done in sweep_code_cache(). This function is the only place in the |
| aoqi@0 | 38 | // sweeper where memory is reclaimed. Note that sweep_code_cache() is not |
| aoqi@0 | 39 | // called at a safepoint. However, sweep_code_cache() stops executing if |
| aoqi@0 | 40 | // another thread requests a safepoint. Consequently, 'mark_active_nmethods()' |
| aoqi@0 | 41 | // and sweep_code_cache() cannot execute at the same time. |
| aoqi@0 | 42 | // To reclaim memory, nmethods are first marked as 'not-entrant'. Methods can |
| aoqi@0 | 43 | // be made not-entrant by (i) the sweeper, (ii) deoptimization, (iii) dependency |
| aoqi@0 | 44 | // invalidation, and (iv) being replaced be a different method version (tiered |
| aoqi@0 | 45 | // compilation). Not-entrant nmethod cannot be called by Java threads, but they |
| aoqi@0 | 46 | // can still be active on the stack. To ensure that active nmethod are not reclaimed, |
| aoqi@0 | 47 | // we have to wait until the next marking phase has completed. If a not-entrant |
| aoqi@0 | 48 | // nmethod was NOT marked as active, it can be converted to 'zombie' state. To safely |
| aoqi@0 | 49 | // remove the nmethod, all inline caches (IC) that point to the the nmethod must be |
| aoqi@0 | 50 | // cleared. After that, the nmethod can be evicted from the code cache. Each nmethod's |
| aoqi@0 | 51 | // state change happens during separate sweeps. It may take at least 3 sweeps before an |
| aoqi@0 | 52 | // nmethod's space is freed. Sweeping is currently done by compiler threads between |
| aoqi@0 | 53 | // compilations or at least each 5 sec (NmethodSweepCheckInterval) when the code cache |
| aoqi@0 | 54 | // is full. |
| aoqi@0 | 55 | |
| aoqi@0 | 56 | class NMethodSweeper : public AllStatic { |
| aoqi@0 | 57 | static long _traversals; // Stack scan count, also sweep ID. |
| aoqi@0 | 58 | static long _total_nof_code_cache_sweeps; // Total number of full sweeps of the code cache |
| aoqi@0 | 59 | static long _time_counter; // Virtual time used to periodically invoke sweeper |
| aoqi@0 | 60 | static long _last_sweep; // Value of _time_counter when the last sweep happened |
| aoqi@0 | 61 | static nmethod* _current; // Current nmethod |
| aoqi@0 | 62 | static int _seen; // Nof. nmethod we have currently processed in current pass of CodeCache |
| aoqi@0 | 63 | static int _flushed_count; // Nof. nmethods flushed in current sweep |
| aoqi@0 | 64 | static int _zombified_count; // Nof. nmethods made zombie in current sweep |
| aoqi@0 | 65 | static int _marked_for_reclamation_count; // Nof. nmethods marked for reclaim in current sweep |
| aoqi@0 | 66 | |
| aoqi@0 | 67 | static volatile int _sweep_fractions_left; // Nof. invocations left until we are completed with this pass |
| aoqi@0 | 68 | static volatile int _sweep_started; // Flag to control conc sweeper |
| aoqi@0 | 69 | static volatile bool _should_sweep; // Indicates if we should invoke the sweeper |
| aoqi@0 | 70 | static volatile int _bytes_changed; // Counts the total nmethod size if the nmethod changed from: |
| aoqi@0 | 71 | // 1) alive -> not_entrant |
| aoqi@0 | 72 | // 2) not_entrant -> zombie |
| aoqi@0 | 73 | // 3) zombie -> marked_for_reclamation |
| aoqi@0 | 74 | // Stat counters |
| aoqi@0 | 75 | static long _total_nof_methods_reclaimed; // Accumulated nof methods flushed |
| aoqi@0 | 76 | static long _total_nof_c2_methods_reclaimed; // Accumulated nof C2-compiled methods flushed |
| aoqi@0 | 77 | static size_t _total_flushed_size; // Total size of flushed methods |
| aoqi@0 | 78 | static int _hotness_counter_reset_val; |
| aoqi@0 | 79 | |
| aoqi@0 | 80 | static Tickspan _total_time_sweeping; // Accumulated time sweeping |
| aoqi@0 | 81 | static Tickspan _total_time_this_sweep; // Total time this sweep |
| aoqi@0 | 82 | static Tickspan _peak_sweep_time; // Peak time for a full sweep |
| aoqi@0 | 83 | static Tickspan _peak_sweep_fraction_time; // Peak time sweeping one fraction |
| aoqi@0 | 84 | |
| aoqi@0 | 85 | static int process_nmethod(nmethod *nm); |
| aoqi@0 | 86 | static void release_nmethod(nmethod* nm); |
| aoqi@0 | 87 | |
| aoqi@0 | 88 | static bool sweep_in_progress(); |
| aoqi@0 | 89 | static void sweep_code_cache(); |
| aoqi@0 | 90 | |
| aoqi@0 | 91 | public: |
| aoqi@0 | 92 | static long traversal_count() { return _traversals; } |
| aoqi@0 | 93 | static int total_nof_methods_reclaimed() { return _total_nof_methods_reclaimed; } |
| aoqi@0 | 94 | static const Tickspan total_time_sweeping() { return _total_time_sweeping; } |
| aoqi@0 | 95 | static const Tickspan peak_sweep_time() { return _peak_sweep_time; } |
| aoqi@0 | 96 | static const Tickspan peak_sweep_fraction_time() { return _peak_sweep_fraction_time; } |
| aoqi@0 | 97 | static void log_sweep(const char* msg, const char* format = NULL, ...) ATTRIBUTE_PRINTF(2, 3); |
| aoqi@0 | 98 | |
| aoqi@0 | 99 | |
| aoqi@0 | 100 | #ifdef ASSERT |
| aoqi@0 | 101 | static bool is_sweeping(nmethod* which) { return _current == which; } |
| aoqi@0 | 102 | // Keep track of sweeper activity in the ring buffer |
| aoqi@0 | 103 | static void record_sweep(nmethod* nm, int line); |
| aoqi@0 | 104 | static void report_events(int id, address entry); |
| aoqi@0 | 105 | static void report_events(); |
| aoqi@0 | 106 | #endif |
| aoqi@0 | 107 | |
| aoqi@0 | 108 | static void mark_active_nmethods(); // Invoked at the end of each safepoint |
| aoqi@0 | 109 | static void possibly_sweep(); // Compiler threads call this to sweep |
| aoqi@0 | 110 | |
| aoqi@0 | 111 | static int hotness_counter_reset_val(); |
| aoqi@0 | 112 | static void report_state_change(nmethod* nm); |
| aoqi@0 | 113 | static void possibly_enable_sweeper(); |
| aoqi@0 | 114 | static void print(); // Printing/debugging |
| aoqi@0 | 115 | }; |
| aoqi@0 | 116 | |
| aoqi@0 | 117 | #endif // SHARE_VM_RUNTIME_SWEEPER_HPP |
