1 /* 2 * Copyright (c) 2014, 2019, 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_GC_SHARED_STRINGDEDUP_STRINGDEDUPTHREAD_HPP 26 #define SHARE_GC_SHARED_STRINGDEDUP_STRINGDEDUPTHREAD_HPP 27 28 #include "gc/shared/concurrentGCThread.hpp" 29 #include "gc/shared/stringdedup/stringDedupStat.hpp" 30 31 // 32 // The deduplication thread is where the actual deduplication occurs. It waits for 33 // deduplication candidates to appear on the deduplication queue, removes them from 34 // the queue and tries to deduplicate them. It uses the deduplication hashtable to 35 // find identical, already existing, character arrays on the heap. The thread runs 36 // concurrently with the Java application but participates in safepoints to allow 37 // the GC to adjust and unlink oops from the deduplication queue and table. 38 // 39 class StringDedupThread: public ConcurrentGCThread { 40 protected: 41 static StringDedupThread* _thread; 42 43 StringDedupThread(); 44 ~StringDedupThread(); 45 46 virtual bool is_StringDedup_thread() const { return true; } 47 48 void print_start(const StringDedupStat* last_stat); 49 void print_end(const StringDedupStat* last_stat, const StringDedupStat* total_stat); 50 51 void run_service() { this->do_deduplication(); } 52 void stop_service(); 53 54 void deduplicate_shared_strings(StringDedupStat* stat); 55 protected: 56 virtual void do_deduplication() = 0; 57 58 public: 59 static StringDedupThread* thread(); 60 }; 61 62 template <typename S> 63 class StringDedupThreadImpl : public StringDedupThread { 64 private: 65 StringDedupThreadImpl() { } 66 67 protected: 68 void do_deduplication(); 69 70 public: 71 static void create(); 72 }; 73 74 #endif // SHARE_GC_SHARED_STRINGDEDUP_STRINGDEDUPTHREAD_HPP