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_G1_G1HEAPREGIONATTR_HPP
26 #define SHARE_GC_G1_G1HEAPREGIONATTR_HPP
27
28 #include "gc/g1/g1BiasedArray.hpp"
29 #include "gc/g1/heapRegion.hpp"
30
31 // Per-region attributes often used during garbage collection to avoid costly
32 // lookups for that information all over the place.
33 struct G1HeapRegionAttr {
34 public:
35 // We use different types to represent the state value depending on platform as
36 // some have issues loading parts of words.
37 #ifdef SPARC
38 typedef int32_t region_type_t;
39 typedef uint32_t needs_remset_update_t;
40 #else
41 typedef int8_t region_type_t;
42 typedef uint8_t needs_remset_update_t;
43 #endif
44
45 private:
46 needs_remset_update_t _needs_remset_update;
47 region_type_t _type;
48
49 public:
50 // Selection of the values for the _type field were driven to micro-optimize the
51 // encoding and frequency of the checks.
52 // The most common check for a given reference is whether the region is in the
53 // collection set or not, and which generation this region is in.
54 // The selected encoding allows us to use a single check (> NotInCSet) for the
55 // former.
56 //
57 // The other values are used for objects in regions requiring various special handling,
58 // eager reclamation of humongous objects or optional regions.
59 static const region_type_t Optional = -3; // The region is optional not in the current collection set.
60 static const region_type_t Humongous = -2; // The region is a humongous candidate not in the current collection set.
61 static const region_type_t NotInCSet = -1; // The region is not in the collection set.
62 static const region_type_t Young = 0; // The region is in the collection set and a young region.
63 static const region_type_t Old = 1; // The region is in the collection set and an old region.
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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_G1_G1HEAPREGIONATTR_HPP
26 #define SHARE_GC_G1_G1HEAPREGIONATTR_HPP
27
28 #include "gc/g1/g1BiasedArray.hpp"
29 #include "gc/g1/heapRegion.hpp"
30
31 // Per-region attributes often used during garbage collection to avoid costly
32 // lookups for that information all over the place.
33 struct G1HeapRegionAttr {
34 public:
35 // We use different types to represent the state value depending on platform as
36 // some have issues loading parts of words.
37 typedef int8_t region_type_t;
38 typedef uint8_t needs_remset_update_t;
39
40 private:
41 needs_remset_update_t _needs_remset_update;
42 region_type_t _type;
43
44 public:
45 // Selection of the values for the _type field were driven to micro-optimize the
46 // encoding and frequency of the checks.
47 // The most common check for a given reference is whether the region is in the
48 // collection set or not, and which generation this region is in.
49 // The selected encoding allows us to use a single check (> NotInCSet) for the
50 // former.
51 //
52 // The other values are used for objects in regions requiring various special handling,
53 // eager reclamation of humongous objects or optional regions.
54 static const region_type_t Optional = -3; // The region is optional not in the current collection set.
55 static const region_type_t Humongous = -2; // The region is a humongous candidate not in the current collection set.
56 static const region_type_t NotInCSet = -1; // The region is not in the collection set.
57 static const region_type_t Young = 0; // The region is in the collection set and a young region.
58 static const region_type_t Old = 1; // The region is in the collection set and an old region.
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