Thu, 26 Jun 2014 11:36:58 +0200
8047818: G1 HeapRegions can no longer be ContiguousSpaces
Summary: Change parent of G1OffsetTableContigSpace to CompactibleSpace, reimplement missing functionality
Reviewed-by: stefank, jmasa, tschatzl
1 /*
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25 #include "precompiled.hpp"
26 #include "memory/allocation.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "memory/memRegion.hpp"
29 #include "runtime/globals.hpp"
31 // A very simple data structure representing a contigous word-aligned
32 // region of address space.
34 MemRegion MemRegion::intersection(const MemRegion mr2) const {
35 MemRegion res;
36 HeapWord* res_start = MAX2(start(), mr2.start());
37 HeapWord* res_end = MIN2(end(), mr2.end());
38 if (res_start < res_end) {
39 res.set_start(res_start);
40 res.set_end(res_end);
41 }
42 return res;
43 }
45 MemRegion MemRegion::_union(const MemRegion mr2) const {
46 // If one region is empty, return the other
47 if (is_empty()) return mr2;
48 if (mr2.is_empty()) return MemRegion(start(), end());
50 // Otherwise, regions must overlap or be adjacent
51 assert(((start() <= mr2.start()) && (end() >= mr2.start())) ||
52 ((mr2.start() <= start()) && (mr2.end() >= start())),
53 "non-adjacent or overlapping regions");
54 MemRegion res;
55 HeapWord* res_start = MIN2(start(), mr2.start());
56 HeapWord* res_end = MAX2(end(), mr2.end());
57 res.set_start(res_start);
58 res.set_end(res_end);
59 return res;
60 }
62 MemRegion MemRegion::minus(const MemRegion mr2) const {
63 // There seem to be 6 cases:
64 // |this MemRegion|
65 // |strictly below|
66 // |overlap beginning|
67 // |interior|
68 // |overlap ending|
69 // |strictly above|
70 // |completely overlapping|
71 // We can't deal with an interior case because it would
72 // produce two disjoint regions as a result.
73 // We aren't trying to be optimal in the number of tests below,
74 // but the order is important to distinguish the strictly cases
75 // from the overlapping cases.
76 if (mr2.end() <= start()) {
77 // strictly below
78 return MemRegion(start(), end());
79 }
80 if (mr2.start() <= start() && mr2.end() <= end()) {
81 // overlap beginning
82 return MemRegion(mr2.end(), end());
83 }
84 if (mr2.start() >= end()) {
85 // strictly above
86 return MemRegion(start(), end());
87 }
88 if (mr2.start() >= start() && mr2.end() >= end()) {
89 // overlap ending
90 return MemRegion(start(), mr2.start());
91 }
92 if (mr2.start() <= start() && mr2.end() >= end()) {
93 // completely overlapping
94 return MemRegion();
95 }
96 if (mr2.start() > start() && mr2.end() < end()) {
97 // interior
98 guarantee(false, "MemRegion::minus, but interior");
99 return MemRegion();
100 }
101 ShouldNotReachHere();
102 return MemRegion();
103 }
105 void* MemRegion::operator new(size_t size) throw() {
106 return (address)AllocateHeap(size, mtGC, 0, AllocFailStrategy::RETURN_NULL);
107 }
109 void* MemRegion::operator new [](size_t size) throw() {
110 return (address)AllocateHeap(size, mtGC, 0, AllocFailStrategy::RETURN_NULL);
111 }
112 void MemRegion::operator delete(void* p) {
113 FreeHeap(p, mtGC);
114 }
116 void MemRegion::operator delete [](void* p) {
117 FreeHeap(p, mtGC);
118 }