Mercurial > jdk8-mips64-public > hotspot / file comparison

comparison: src/share/vm/gc_implementation/g1/g1AllocRegion.hpp

src/share/vm/gc_implementation/g1/g1AllocRegion.hpp

changeset 3028
f44782f04dd4
parent 2715
abdfc822206f
child 3713
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equal deleted inserted replaced
3027:87e40b34bc2b 3028:f44782f04dd4
34 34
35 class ar_ext_msg; 35 class ar_ext_msg;
36 36
37 // A class that holds a region that is active in satisfying allocation 37 // A class that holds a region that is active in satisfying allocation
38 // requests, potentially issued in parallel. When the active region is 38 // requests, potentially issued in parallel. When the active region is
39 // full it will be retired it replaced with a new one. The 39 // full it will be retired and replaced with a new one. The
40 // implementation assumes that fast-path allocations will be lock-free 40 // implementation assumes that fast-path allocations will be lock-free
41 // and a lock will need to be taken when the active region needs to be 41 // and a lock will need to be taken when the active region needs to be
42 // replaced. 42 // replaced.
43 43
44 class G1AllocRegion VALUE_OBJ_CLASS_SPEC { 44 class G1AllocRegion VALUE_OBJ_CLASS_SPEC {
55 // then _alloc_region is NULL and this object should not be used to 55 // then _alloc_region is NULL and this object should not be used to
56 // satisfy allocation requests (it was done this way to force the 56 // satisfy allocation requests (it was done this way to force the
57 // correct use of init() and release()). 57 // correct use of init() and release()).
58 HeapRegion* _alloc_region; 58 HeapRegion* _alloc_region;
59 59
60 // It keeps track of the distinct number of regions that are used
61 // for allocation in the active interval of this object, i.e.,
62 // between a call to init() and a call to release(). The count
63 // mostly includes regions that are freshly allocated, as well as
64 // the region that is re-used using the set() method. This count can
65 // be used in any heuristics that might want to bound how many
66 // distinct regions this object can used during an active interval.
67 size_t _count;
68
60 // When we set up a new active region we save its used bytes in this 69 // When we set up a new active region we save its used bytes in this
61 // field so that, when we retire it, we can calculate how much space 70 // field so that, when we retire it, we can calculate how much space
62 // we allocated in it. 71 // we allocated in it.
63 size_t _used_bytes_before; 72 size_t _used_bytes_before;
64 73
65 // Specifies whether the allocate calls will do BOT updates or not. 74 // When true, indicates that allocate calls should do BOT updates.
66 bool _bot_updates; 75 const bool _bot_updates;
67 76
68 // Useful for debugging and tracing. 77 // Useful for debugging and tracing.
69 const char* _name; 78 const char* _name;
70 79
71 // A dummy region (i.e., it's been allocated specially for this 80 // A dummy region (i.e., it's been allocated specially for this
125 HeapRegion* get() const { 134 HeapRegion* get() const {
126 // Make sure that the dummy region does not escape this class. 135 // Make sure that the dummy region does not escape this class.
127 return (_alloc_region == _dummy_region) ? NULL : _alloc_region; 136 return (_alloc_region == _dummy_region) ? NULL : _alloc_region;
128 } 137 }
129 138
139 size_t count() { return _count; }
140
130 // The following two are the building blocks for the allocation method. 141 // The following two are the building blocks for the allocation method.
131 142
132 // First-level allocation: Should be called without holding a 143 // First-level allocation: Should be called without holding a
133 // lock. It will try to allocate lock-free out of the active region, 144 // lock. It will try to allocate lock-free out of the active region,
134 // or return NULL if it was unable to. 145 // or return NULL if it was unable to.
151 bool bot_updates); 162 bool bot_updates);
152 163
153 // Should be called before we start using this object. 164 // Should be called before we start using this object.
154 void init(); 165 void init();
155 166
167 // This can be used to set the active region to a specific
168 // region. (Use Example: we try to retain the last old GC alloc
169 // region that we've used during a GC and we can use set() to
170 // re-instate it at the beginning of the next GC.)
171 void set(HeapRegion* alloc_region);
172
156 // Should be called when we want to release the active region which 173 // Should be called when we want to release the active region which
157 // is returned after it's been retired. 174 // is returned after it's been retired.
158 HeapRegion* release(); 175 HeapRegion* release();
159 176
160 #if G1_ALLOC_REGION_TRACING 177 #if G1_ALLOC_REGION_TRACING

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