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 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 #include "gc/z/zThreadLocalData.hpp"
25 #include "gc/z/zObjArrayAllocator.hpp"
26 #include "gc/z/zUtils.inline.hpp"
27 #include "oops/arrayKlass.hpp"
28 #include "runtime/interfaceSupport.inline.hpp"
29 #include "utilities/debug.hpp"
30
31 ZObjArrayAllocator::ZObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero, Thread* thread)
32 : ObjArrayAllocator(klass, word_size, length, do_zero, thread) {}
33
34 void ZObjArrayAllocator::yield_for_safepoint() const {
35 ThreadBlockInVM tbivm(JavaThread::cast(_thread));
36 }
37
38 oop ZObjArrayAllocator::initialize(HeapWord* mem) const {
39 // ZGC specializes the initialization by performing segmented clearing
40 // to allow shorter time-to-safepoints.
41
42 if (!_do_zero) {
43 // No need for ZGC specialization
44 return ObjArrayAllocator::initialize(mem);
45 }
46
47 // A max segment size of 64K was chosen because microbenchmarking
48 // suggested that it offered a good trade-off between allocation
49 // time and time-to-safepoint
50 const size_t segment_max = ZUtils::bytes_to_words(64 * K);
51
52 if (_word_size <= segment_max) {
53 // To small to use segmented clearing
54 return ObjArrayAllocator::initialize(mem);
55 }
56
57 // Segmented clearing
58
59 // The array is going to be exposed before it has been completely
60 // cleared, therefore we can't expose the header at the end of this
61 // function. Instead explicitly initialize it according to our needs.
62
63 // Signal to the ZIterator that this is an invisible root, by setting
64 // the mark word to "marked". Reset to prototype() after the clearing.
65 if (UseCompactObjectHeaders) {
66 oopDesc::release_set_mark(mem, _klass->prototype_header().set_marked());
67 } else {
68 arrayOopDesc::set_mark(mem, markWord::prototype().set_marked());
69 arrayOopDesc::release_set_klass(mem, _klass);
70 }
71 assert(_length >= 0, "length should be non-negative");
72 arrayOopDesc::set_length(mem, _length);
73
74 // Keep the array alive across safepoints through an invisible
75 // root. Invisible roots are not visited by the heap iterator
76 // and the marking logic will not attempt to follow its elements.
77 // Relocation and remembered set code know how to dodge iterating
78 // over such objects.
79 ZThreadLocalData::set_invisible_root(_thread, (zaddress_unsafe*)&mem);
80
81 const BasicType element_type = ArrayKlass::cast(_klass)->element_type();
82 const size_t base_offset_in_bytes = (size_t)arrayOopDesc::base_offset_in_bytes(element_type);
83 const size_t process_start_offset_in_bytes = align_up(base_offset_in_bytes, (size_t)BytesPerWord);
84
85 if (process_start_offset_in_bytes != base_offset_in_bytes) {
86 // initialize_memory can only fill word aligned memory,
87 // fill the first 4 bytes here.
88 assert(process_start_offset_in_bytes - base_offset_in_bytes == 4, "Must be 4-byte aligned");
138 seen_gc_safepoint = true;
139 return false;
140 }
141 }
142 return true;
143 };
144
145 mem_zap_start_padding(mem);
146
147 if (!initialize_memory()) {
148 // Re-color with 11 remset bits if we got intercepted by a GC safepoint
149 const bool result = initialize_memory();
150 assert(result, "Array initialization should always succeed the second time");
151 }
152
153 mem_zap_end_padding(mem);
154
155 ZThreadLocalData::clear_invisible_root(_thread);
156
157 // Signal to the ZIterator that this is no longer an invisible root
158 if (UseCompactObjectHeaders) {
159 oopDesc::release_set_mark(mem, _klass->prototype_header());
160 } else {
161 oopDesc::release_set_mark(mem, markWord::prototype());
162 }
163
164 return cast_to_oop(mem);
165 }
|
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 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 #include "gc/z/zThreadLocalData.hpp"
25 #include "gc/z/zObjArrayAllocator.hpp"
26 #include "gc/z/zUtils.inline.hpp"
27 #include "oops/arrayKlass.hpp"
28 #include "runtime/interfaceSupport.inline.hpp"
29 #include "utilities/debug.hpp"
30 #include "utilities/globalDefinitions.hpp"
31
32 ZObjArrayAllocator::ZObjArrayAllocator(Klass* klass, size_t word_size, int length, bool do_zero, Thread* thread)
33 : ObjArrayAllocator(klass, word_size, length, do_zero, thread) {}
34
35 void ZObjArrayAllocator::yield_for_safepoint() const {
36 ThreadBlockInVM tbivm(JavaThread::cast(_thread));
37 }
38
39 oop ZObjArrayAllocator::initialize(HeapWord* mem) const {
40 // ZGC specializes the initialization by performing segmented clearing
41 // to allow shorter time-to-safepoints.
42
43 if (!_do_zero) {
44 // No need for ZGC specialization
45 return ObjArrayAllocator::initialize(mem);
46 }
47
48 // A max segment size of 64K was chosen because microbenchmarking
49 // suggested that it offered a good trade-off between allocation
50 // time and time-to-safepoint
51 const size_t segment_max = ZUtils::bytes_to_words(64 * K);
52
53 if (_word_size <= segment_max || ArrayKlass::cast(_klass)->is_flatArray_klass()) {
54 // To small to use segmented clearing
55 return ObjArrayAllocator::initialize(mem);
56 }
57
58 // Segmented clearing
59
60 // The array is going to be exposed before it has been completely
61 // cleared, therefore we can't expose the header at the end of this
62 // function. Instead explicitly initialize it according to our needs.
63
64 // Signal to the ZIterator that this is an invisible root, by setting
65 // the mark word to "marked". Reset to prototype() after the clearing.
66 if (UseCompactObjectHeaders) {
67 oopDesc::release_set_mark(mem, _klass->prototype_header().set_marked());
68 } else {
69 if (EnableValhalla) {
70 arrayOopDesc::set_mark(mem, _klass->prototype_header().set_marked());
71 } else {
72 arrayOopDesc::set_mark(mem, markWord::prototype().set_marked());
73 }
74 arrayOopDesc::release_set_klass(mem, _klass);
75 }
76 assert(_length >= 0, "length should be non-negative");
77 arrayOopDesc::set_length(mem, _length);
78
79 // Keep the array alive across safepoints through an invisible
80 // root. Invisible roots are not visited by the heap iterator
81 // and the marking logic will not attempt to follow its elements.
82 // Relocation and remembered set code know how to dodge iterating
83 // over such objects.
84 ZThreadLocalData::set_invisible_root(_thread, (zaddress_unsafe*)&mem);
85
86 const BasicType element_type = ArrayKlass::cast(_klass)->element_type();
87 const size_t base_offset_in_bytes = (size_t)arrayOopDesc::base_offset_in_bytes(element_type);
88 const size_t process_start_offset_in_bytes = align_up(base_offset_in_bytes, (size_t)BytesPerWord);
89
90 if (process_start_offset_in_bytes != base_offset_in_bytes) {
91 // initialize_memory can only fill word aligned memory,
92 // fill the first 4 bytes here.
93 assert(process_start_offset_in_bytes - base_offset_in_bytes == 4, "Must be 4-byte aligned");
143 seen_gc_safepoint = true;
144 return false;
145 }
146 }
147 return true;
148 };
149
150 mem_zap_start_padding(mem);
151
152 if (!initialize_memory()) {
153 // Re-color with 11 remset bits if we got intercepted by a GC safepoint
154 const bool result = initialize_memory();
155 assert(result, "Array initialization should always succeed the second time");
156 }
157
158 mem_zap_end_padding(mem);
159
160 ZThreadLocalData::clear_invisible_root(_thread);
161
162 // Signal to the ZIterator that this is no longer an invisible root
163 if (UseCompactObjectHeaders || EnableValhalla) {
164 oopDesc::release_set_mark(mem, _klass->prototype_header());
165 } else {
166 oopDesc::release_set_mark(mem, markWord::prototype());
167 }
168
169 return cast_to_oop(mem);
170 }
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