1 /* 2 * Copyright (c) 2016, 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_G1_G1HEAPSIZINGPOLICY_HPP 26 #define SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP 27 28 #include "memory/allocation.hpp" 29 30 class G1Analytics; 31 class G1CollectedHeap; 32 33 class G1HeapSizingPolicy: public CHeapObj<mtGC> { 34 // MinOverThresholdForGrowth must be less than the number of recorded 35 // pause times in G1Analytics, representing the minimum number of pause 36 // time ratios that exceed GCTimeRatio before a heap expansion will be triggered. 37 const static uint MinOverThresholdForGrowth = 4; 38 39 const G1CollectedHeap* _g1h; 40 const G1Analytics* _analytics; 41 42 const uint _num_prev_pauses_for_heuristics; 43 // Ratio check data for determining if heap growth is necessary. 44 uint _ratio_over_threshold_count; 45 double _ratio_over_threshold_sum; 46 uint _pauses_since_start; 47 48 // Mininum heap capacity after last concurrent mark 49 size_t _minimum_desired_bytes_after_last_cm; 50 51 52 protected: 53 G1HeapSizingPolicy(const G1CollectedHeap* g1h, const G1Analytics* analytics); 54 public: 55 56 // If an expansion would be appropriate, because recent GC overhead had 57 // exceeded the desired limit, return an amount to expand by. 58 virtual size_t expansion_amount_after_young_collection(); 59 virtual size_t expansion_amount_after_concurrent_mark(); 60 virtual size_t shrink_amount_after_mixed_collections(); 61 62 // Clear ratio tracking data used by expansion_amount(). 63 void clear_ratio_check_data(); 64 65 static G1HeapSizingPolicy* create(const G1CollectedHeap* g1h, const G1Analytics* analytics); 66 }; 67 68 #endif // SHARE_GC_G1_G1HEAPSIZINGPOLICY_HPP