1/*
2 * Copyright (c) 2016, 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24#ifndef SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP
25#define SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP
26
27#include "gc/shenandoah/shenandoahHeapRegionSet.hpp"
28#include "gc/shenandoah/shenandoahHeap.hpp"
29
30class ShenandoahFreeSet : public CHeapObj<mtGC> {
31private:
32 ShenandoahHeap* const _heap;
33 CHeapBitMap _mutator_free_bitmap;
34 CHeapBitMap _collector_free_bitmap;
35 size_t _max;
36
37 // Left-most and right-most region indexes. There are no free regions outside
38 // of [left-most; right-most] index intervals
39 size_t _mutator_leftmost, _mutator_rightmost;
40 size_t _collector_leftmost, _collector_rightmost;
41
42 size_t _capacity;
43 size_t _used;
44
45 void assert_bounds() const NOT_DEBUG_RETURN;
46 void assert_heaplock_owned_by_current_thread() const NOT_DEBUG_RETURN;
47 void assert_heaplock_not_owned_by_current_thread() const NOT_DEBUG_RETURN;
48
49 bool is_mutator_free(size_t idx) const;
50 bool is_collector_free(size_t idx) const;
51
52 HeapWord* try_allocate_in(ShenandoahHeapRegion* region, ShenandoahAllocRequest& req, bool& in_new_region);
53 HeapWord* allocate_single(ShenandoahAllocRequest& req, bool& in_new_region);
54 HeapWord* allocate_contiguous(ShenandoahAllocRequest& req);
55
56 void flip_to_gc(ShenandoahHeapRegion* r);
57
58 void recompute_bounds();
59 void adjust_bounds();
60 bool touches_bounds(size_t num) const;
61
62 void increase_used(size_t amount);
63 void clear_internal();
64
65 size_t collector_count() const { return _collector_free_bitmap.count_one_bits(); }
66 size_t mutator_count() const { return _mutator_free_bitmap.count_one_bits(); }
67
68 void try_recycle_trashed(ShenandoahHeapRegion *r);
69
70 bool is_empty_or_trash(ShenandoahHeapRegion *r);
71 size_t alloc_capacity(ShenandoahHeapRegion *r);
72 bool has_no_alloc_capacity(ShenandoahHeapRegion *r);
73
74public:
75 ShenandoahFreeSet(ShenandoahHeap* heap, size_t max_regions);
76
77 void clear();
78 void rebuild();
79
80 void recycle_trash();
81
82 void log_status();
83
84 size_t capacity() const { return _capacity; }
85 size_t used() const { return _used; }
86 size_t available() const {
87 assert(_used <= _capacity, "must use less than capacity");
88 return _capacity - _used;
89 }
90
91 HeapWord* allocate(ShenandoahAllocRequest& req, bool& in_new_region);
92 size_t unsafe_peek_free() const;
93
94 void print_on(outputStream* out) const;
95};
96
97#endif // SHARE_GC_SHENANDOAH_SHENANDOAHFREESET_HPP
98