1 /* 2 * Copyright (c) 2016, 2019, Red Hat, Inc. 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_SHENANDOAH_SHENANDOAHFREESET_HPP 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP 27 28 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 29 #include "gc/shenandoah/shenandoahHeap.hpp" 30 31 class ShenandoahFreeSet : public CHeapObj<mtGC> { 32 private: 33 ShenandoahHeap* const _heap; 34 CHeapBitMap _mutator_free_bitmap; 35 CHeapBitMap _collector_free_bitmap; 36 size_t _max; 37 38 // Left-most and right-most region indexes. There are no free regions outside 39 // of [left-most; right-most] index intervals 40 size_t _mutator_leftmost, _mutator_rightmost; 41 size_t _collector_leftmost, _collector_rightmost; 42 43 size_t _capacity; 44 size_t _used; 45 46 void assert_bounds() const NOT_DEBUG_RETURN; 47 48 bool is_mutator_free(size_t idx) const; 49 bool is_collector_free(size_t idx) const; 50 51 HeapWord* try_allocate_in(ShenandoahHeapRegion* region, ShenandoahAllocRequest& req, bool& in_new_region); 52 HeapWord* allocate_with_affiliation(ShenandoahRegionAffiliation affiliation, ShenandoahAllocRequest& req, bool& in_new_region); 53 HeapWord* allocate_with_old_affiliation(ShenandoahAllocRequest& req, bool& in_new_region); 54 55 // While holding the heap lock, allocate memory for a single object which is to be entirely contained 56 // within a single HeapRegion as characterized by req. The req.size() value is known to be less than or 57 // equal to ShenandoahHeapRegion::humongous_threshold_words(). The caller of allocate_single is responsible 58 // for registering the resulting object and setting the remembered set card values as appropriate. The 59 // most common case is that we are allocating a PLAB in which case object registering and card dirtying 60 // is managed after the PLAB is divided into individual objects. 61 HeapWord* allocate_single(ShenandoahAllocRequest& req, bool& in_new_region); 62 HeapWord* allocate_contiguous(ShenandoahAllocRequest& req); 63 64 void flip_to_gc(ShenandoahHeapRegion* r); 65 66 void recompute_bounds(); 67 void adjust_bounds(); 68 bool touches_bounds(size_t num) const; 69 70 void increase_used(size_t amount); 71 void clear_internal(); 72 73 void try_recycle_trashed(ShenandoahHeapRegion *r); 74 75 bool can_allocate_from(ShenandoahHeapRegion *r); 76 size_t alloc_capacity(ShenandoahHeapRegion *r); 77 bool has_no_alloc_capacity(ShenandoahHeapRegion *r); 78 79 public: 80 ShenandoahFreeSet(ShenandoahHeap* heap, size_t max_regions); 81 82 // Number of regions dedicated to GC allocations (for evacuation or promotion) that are currently free 83 size_t collector_count() const { return _collector_free_bitmap.count_one_bits(); } 84 85 // Number of regions dedicated to mutator allocations that are currently free 86 size_t mutator_count() const { return _mutator_free_bitmap.count_one_bits(); } 87 88 void clear(); 89 void rebuild(); 90 91 void recycle_trash(); 92 93 void log_status(); 94 95 size_t capacity() const { return _capacity; } 96 size_t used() const { return _used; } 97 size_t available() const { 98 assert(_used <= _capacity, "must use less than capacity"); 99 return _capacity - _used; 100 } 101 102 HeapWord* allocate(ShenandoahAllocRequest& req, bool& in_new_region); 103 size_t unsafe_peek_free() const; 104 105 double internal_fragmentation(); 106 double external_fragmentation(); 107 108 void print_on(outputStream* out) const; 109 110 void reserve_regions(size_t to_reserve); 111 }; 112 113 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP