56 if (!is_aligned(base_offset, HeapWordSize)) {
57 assert(is_aligned(base_offset, BytesPerInt), "array base must be 32 bit aligned");
58 *reinterpret_cast<jint*>(reinterpret_cast<char*>(mem) + base_offset) = 0;
59 base_offset += BytesPerInt;
60 }
61 assert(is_aligned(base_offset, HeapWordSize), "remaining array base must be 64 bit aligned");
62
63 const size_t header = heap_word_size(base_offset);
64 const size_t payload_size = _word_size - header;
65
66 if (payload_size <= segment_max) {
67 // To small to use segmented clearing
68 return ObjArrayAllocator::initialize(mem);
69 }
70
71 // Segmented clearing
72
73 // The array is going to be exposed before it has been completely
74 // cleared, therefore we can't expose the header at the end of this
75 // function. Instead explicitly initialize it according to our needs.
76 arrayOopDesc::set_mark(mem, markWord::prototype());
77 arrayOopDesc::release_set_klass(mem, _klass);
78 assert(_length >= 0, "length should be non-negative");
79 arrayOopDesc::set_length(mem, _length);
80
81 // Keep the array alive across safepoints through an invisible
82 // root. Invisible roots are not visited by the heap itarator
83 // and the marking logic will not attempt to follow its elements.
84 // Relocation knows how to dodge iterating over such objects.
85 XThreadLocalData::set_invisible_root(_thread, (oop*)&mem);
86
87 for (size_t processed = 0; processed < payload_size; processed += segment_max) {
88 // Calculate segment
89 HeapWord* const start = (HeapWord*)(mem + header + processed);
90 const size_t remaining = payload_size - processed;
91 const size_t segment_size = MIN2(remaining, segment_max);
92
93 // Clear segment
94 Copy::zero_to_words(start, segment_size);
95
96 // Safepoint
97 yield_for_safepoint();
|
56 if (!is_aligned(base_offset, HeapWordSize)) {
57 assert(is_aligned(base_offset, BytesPerInt), "array base must be 32 bit aligned");
58 *reinterpret_cast<jint*>(reinterpret_cast<char*>(mem) + base_offset) = 0;
59 base_offset += BytesPerInt;
60 }
61 assert(is_aligned(base_offset, HeapWordSize), "remaining array base must be 64 bit aligned");
62
63 const size_t header = heap_word_size(base_offset);
64 const size_t payload_size = _word_size - header;
65
66 if (payload_size <= segment_max) {
67 // To small to use segmented clearing
68 return ObjArrayAllocator::initialize(mem);
69 }
70
71 // Segmented clearing
72
73 // The array is going to be exposed before it has been completely
74 // cleared, therefore we can't expose the header at the end of this
75 // function. Instead explicitly initialize it according to our needs.
76 if (UseCompactObjectHeaders) {
77 arrayOopDesc::release_set_mark(mem, _klass->prototype_header());
78 } else {
79 arrayOopDesc::set_mark(mem, markWord::prototype());
80 arrayOopDesc::release_set_klass(mem, _klass);
81 }
82 assert(_length >= 0, "length should be non-negative");
83 arrayOopDesc::set_length(mem, _length);
84
85 // Keep the array alive across safepoints through an invisible
86 // root. Invisible roots are not visited by the heap itarator
87 // and the marking logic will not attempt to follow its elements.
88 // Relocation knows how to dodge iterating over such objects.
89 XThreadLocalData::set_invisible_root(_thread, (oop*)&mem);
90
91 for (size_t processed = 0; processed < payload_size; processed += segment_max) {
92 // Calculate segment
93 HeapWord* const start = (HeapWord*)(mem + header + processed);
94 const size_t remaining = payload_size - processed;
95 const size_t segment_size = MIN2(remaining, segment_max);
96
97 // Clear segment
98 Copy::zero_to_words(start, segment_size);
99
100 // Safepoint
101 yield_for_safepoint();
|