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comparison src/share/vm/classfile/metadataOnStackMark.cpp @ 20619:b12a2a9b05ca

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8056240: Investigate increased GC remark time after class unloading changes in CRM Fuse Reviewed-by: mgerdin, coleenp, bdelsart
author stefank
date Thu, 02 Oct 2014 10:55:36 +0200
parents 2c6ef90f030a
children 76af33d4d504
comparison
equal deleted inserted replaced
20618:7024b693c8f9 20619:b12a2a9b05ca
29 #include "oops/metadata.hpp" 29 #include "oops/metadata.hpp"
30 #include "prims/jvmtiImpl.hpp" 30 #include "prims/jvmtiImpl.hpp"
31 #include "runtime/synchronizer.hpp" 31 #include "runtime/synchronizer.hpp"
32 #include "runtime/thread.hpp" 32 #include "runtime/thread.hpp"
33 #include "services/threadService.hpp" 33 #include "services/threadService.hpp"
34 #include "utilities/growableArray.hpp" 34 #include "utilities/chunkedList.hpp"
35 35
36 volatile MetadataOnStackBuffer* MetadataOnStackMark::_used_buffers = NULL;
37 volatile MetadataOnStackBuffer* MetadataOnStackMark::_free_buffers = NULL;
36 38
37 // Keep track of marked on-stack metadata so it can be cleared.
38 GrowableArray<Metadata*>* _marked_objects = NULL;
39 NOT_PRODUCT(bool MetadataOnStackMark::_is_active = false;) 39 NOT_PRODUCT(bool MetadataOnStackMark::_is_active = false;)
40 40
41 // Walk metadata on the stack and mark it so that redefinition doesn't delete 41 // Walk metadata on the stack and mark it so that redefinition doesn't delete
42 // it. Class unloading also walks the previous versions and might try to 42 // it. Class unloading also walks the previous versions and might try to
43 // delete it, so this class is used by class unloading also. 43 // delete it, so this class is used by class unloading also.
44 MetadataOnStackMark::MetadataOnStackMark() { 44 MetadataOnStackMark::MetadataOnStackMark(bool visit_code_cache) {
45 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 45 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
46 assert(_used_buffers == NULL, "sanity check");
46 NOT_PRODUCT(_is_active = true;) 47 NOT_PRODUCT(_is_active = true;)
47 if (_marked_objects == NULL) {
48 _marked_objects = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(1000, true);
49 }
50 48
51 Threads::metadata_do(Metadata::mark_on_stack); 49 Threads::metadata_do(Metadata::mark_on_stack);
52 if (JvmtiExport::has_redefined_a_class()) { 50 if (visit_code_cache) {
53 CodeCache::alive_nmethods_do(nmethod::mark_on_stack); 51 CodeCache::alive_nmethods_do(nmethod::mark_on_stack);
54 } 52 }
55 CompileBroker::mark_on_stack(); 53 CompileBroker::mark_on_stack();
56 JvmtiCurrentBreakpoints::metadata_do(Metadata::mark_on_stack); 54 JvmtiCurrentBreakpoints::metadata_do(Metadata::mark_on_stack);
57 ThreadService::metadata_do(Metadata::mark_on_stack); 55 ThreadService::metadata_do(Metadata::mark_on_stack);
60 MetadataOnStackMark::~MetadataOnStackMark() { 58 MetadataOnStackMark::~MetadataOnStackMark() {
61 assert(SafepointSynchronize::is_at_safepoint(), "sanity check"); 59 assert(SafepointSynchronize::is_at_safepoint(), "sanity check");
62 // Unmark everything that was marked. Can't do the same walk because 60 // Unmark everything that was marked. Can't do the same walk because
63 // redefine classes messes up the code cache so the set of methods 61 // redefine classes messes up the code cache so the set of methods
64 // might not be the same. 62 // might not be the same.
65 for (int i = 0; i< _marked_objects->length(); i++) { 63
66 _marked_objects->at(i)->set_on_stack(false); 64 retire_buffer_for_thread(Thread::current());
65
66 MetadataOnStackBuffer* buffer = const_cast<MetadataOnStackBuffer* >(_used_buffers);
67 while (buffer != NULL) {
68 // Clear on stack state for all metadata.
69 size_t size = buffer->size();
70 for (size_t i = 0; i < size; i++) {
71 Metadata* md = buffer->at(i);
72 md->set_on_stack(false);
73 }
74
75 MetadataOnStackBuffer* next = buffer->next_used();
76
77 // Move the buffer to the free list.
78 buffer->clear();
79 buffer->set_next_used(NULL);
80 buffer->set_next_free(const_cast<MetadataOnStackBuffer*>(_free_buffers));
81 _free_buffers = buffer;
82
83 // Step to next used buffer.
84 buffer = next;
67 } 85 }
68 _marked_objects->clear(); // reuse growable array for next time. 86
87 _used_buffers = NULL;
88
69 NOT_PRODUCT(_is_active = false;) 89 NOT_PRODUCT(_is_active = false;)
70 } 90 }
71 91
92 void MetadataOnStackMark::retire_buffer(MetadataOnStackBuffer* buffer) {
93 if (buffer == NULL) {
94 return;
95 }
96
97 MetadataOnStackBuffer* old_head;
98
99 do {
100 old_head = const_cast<MetadataOnStackBuffer*>(_used_buffers);
101 buffer->set_next_used(old_head);
102 } while (Atomic::cmpxchg_ptr(buffer, &_used_buffers, old_head) != old_head);
103 }
104
105 void MetadataOnStackMark::retire_buffer_for_thread(Thread* thread) {
106 retire_buffer(thread->metadata_on_stack_buffer());
107 thread->set_metadata_on_stack_buffer(NULL);
108 }
109
110 bool MetadataOnStackMark::has_buffer_for_thread(Thread* thread) {
111 return thread->metadata_on_stack_buffer() != NULL;
112 }
113
114 MetadataOnStackBuffer* MetadataOnStackMark::allocate_buffer() {
115 MetadataOnStackBuffer* allocated;
116 MetadataOnStackBuffer* new_head;
117
118 do {
119 allocated = const_cast<MetadataOnStackBuffer*>(_free_buffers);
120 if (allocated == NULL) {
121 break;
122 }
123 new_head = allocated->next_free();
124 } while (Atomic::cmpxchg_ptr(new_head, &_free_buffers, allocated) != allocated);
125
126 if (allocated == NULL) {
127 allocated = new MetadataOnStackBuffer();
128 }
129
130 assert(!allocated->is_full(), err_msg("Should not be full: " PTR_FORMAT, p2i(allocated)));
131
132 return allocated;
133 }
134
72 // Record which objects are marked so we can unmark the same objects. 135 // Record which objects are marked so we can unmark the same objects.
73 void MetadataOnStackMark::record(Metadata* m) { 136 void MetadataOnStackMark::record(Metadata* m, Thread* thread) {
74 assert(_is_active, "metadata on stack marking is active"); 137 assert(_is_active, "metadata on stack marking is active");
75 _marked_objects->push(m); 138
139 MetadataOnStackBuffer* buffer = thread->metadata_on_stack_buffer();
140
141 if (buffer != NULL && buffer->is_full()) {
142 retire_buffer(buffer);
143 buffer = NULL;
144 }
145
146 if (buffer == NULL) {
147 buffer = allocate_buffer();
148 thread->set_metadata_on_stack_buffer(buffer);
149 }
150
151 buffer->push(m);
76 } 152 }