comparison src/share/vm/gc_implementation/g1/heapRegionSeq.hpp @ 342:37f87013dfd8

6711316: Open source the Garbage-First garbage collector Summary: First mercurial integration of the code for the Garbage-First garbage collector. Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author ysr
date Thu, 05 Jun 2008 15:57:56 -0700
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children 078b8a0d8d7c
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-1:000000000000 0:0ad230c8d16f
1 /*
2 * Copyright 2001-2007 Sun Microsystems, 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
24
25 class HeapRegion;
26 class HeapRegionClosure;
27
28 class HeapRegionSeq: public CHeapObj {
29
30 // _regions is kept sorted by start address order, and no two regions are
31 // overlapping.
32 GrowableArray<HeapRegion*> _regions;
33
34 // The index in "_regions" at which to start the next allocation search.
35 // (For efficiency only; private to obj_allocate after initialization.)
36 int _alloc_search_start;
37
38 // Attempts to allocate a block of the (assumed humongous) word_size,
39 // starting at the region "ind".
40 HeapWord* alloc_obj_from_region_index(int ind, size_t word_size);
41
42 // Currently, we're choosing collection sets in a round-robin fashion,
43 // starting here.
44 int _next_rr_candidate;
45
46 // The bottom address of the bottom-most region, or else NULL if there
47 // are no regions in the sequence.
48 char* _seq_bottom;
49
50 public:
51 // Initializes "this" to the empty sequence of regions.
52 HeapRegionSeq();
53
54 // Adds "hr" to "this" sequence. Requires "hr" not to overlap with
55 // any region already in "this". (Will perform better if regions are
56 // inserted in ascending address order.)
57 void insert(HeapRegion* hr);
58
59 // Given a HeapRegion*, returns its index within _regions,
60 // or returns -1 if not found.
61 int find(HeapRegion* hr);
62
63 // Requires the index to be valid, and return the region at the index.
64 HeapRegion* at(size_t i) { return _regions.at((int)i); }
65
66 // Return the number of regions in the sequence.
67 size_t length();
68
69 // Returns the number of contiguous regions at the end of the sequence
70 // that are available for allocation.
71 size_t free_suffix();
72
73 // Requires "word_size" to be humongous (in the technical sense). If
74 // possible, allocates a contiguous subsequence of the heap regions to
75 // satisfy the allocation, and returns the address of the beginning of
76 // that sequence, otherwise returns NULL.
77 HeapWord* obj_allocate(size_t word_size);
78
79 // Apply the "doHeapRegion" method of "blk" to all regions in "this",
80 // in address order, terminating the iteration early
81 // if the "doHeapRegion" method returns "true".
82 void iterate(HeapRegionClosure* blk);
83
84 // Apply the "doHeapRegion" method of "blk" to all regions in "this",
85 // starting at "r" (or first region, if "r" is NULL), in a circular
86 // manner, terminating the iteration early if the "doHeapRegion" method
87 // returns "true".
88 void iterate_from(HeapRegion* r, HeapRegionClosure* blk);
89
90 // As above, but start from a given index in the sequence
91 // instead of a given heap region.
92 void iterate_from(int idx, HeapRegionClosure* blk);
93
94 // Requires "shrink_bytes" to be a multiple of the page size and heap
95 // region granularity. Deletes as many "rightmost" completely free heap
96 // regions from the sequence as comprise shrink_bytes bytes. Returns the
97 // MemRegion indicating the region those regions comprised, and sets
98 // "num_regions_deleted" to the number of regions deleted.
99 MemRegion shrink_by(size_t shrink_bytes, size_t& num_regions_deleted);
100
101 // If "addr" falls within a region in the sequence, return that region,
102 // or else NULL.
103 HeapRegion* addr_to_region(const void* addr);
104
105 void print();
106
107 // Prints out runs of empty regions. If the arg is "true" reserved
108 // (popular regions are considered "empty".
109 void print_empty_runs(bool reserved_are_empty);
110
111 };