Thu, 24 Mar 2011 15:47:01 -0700
7029036: Card-table verification hangs with all framework collectors, except G1, even before the first GC
Summary: When verifying clean card ranges, use memory-range-bounded iteration over oops of objects overlapping that range, thus avoiding the otherwise quadratic worst-case cost of scanning large object arrays.
Reviewed-by: jmasa, jwilhelm, tonyp
1 /*
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25 #include "precompiled.hpp"
26 #include "classfile/symbolTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "memory/filemap.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "utilities/hashtable.inline.hpp"
33 // Closure for serializing initialization data in from a data area
34 // (oop_array) read from the shared file.
36 class ReadClosure : public SerializeOopClosure {
37 private:
38 oop** _oop_array;
40 inline oop nextOop() {
41 return *(*_oop_array)++;
42 }
44 public:
45 ReadClosure(oop** oop_array) { _oop_array = oop_array; }
47 void do_oop(oop* p) {
48 assert(SharedSkipVerify || *p == NULL || *p == Universe::klassKlassObj(),
49 "initializing previously initialized oop.");
50 oop obj = nextOop();
51 assert(SharedSkipVerify || (intptr_t)obj >= 0 || (intptr_t)obj < -100,
52 "hit tag while initializing oops.");
53 assert(SharedSkipVerify || obj->is_oop_or_null(), "invalid oop");
54 *p = obj;
55 }
57 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
59 void do_ptr(void** p) {
60 assert(*p == NULL, "initializing previous initialized pointer.");
61 void* obj = nextOop();
62 assert((intptr_t)obj >= 0 || (intptr_t)obj < -100,
63 "hit tag while initializing ptrs.");
64 *p = obj;
65 }
67 void do_ptr(HeapWord** p) { do_ptr((void **) p); }
69 void do_int(int* p) {
70 *p = (int)(intptr_t)nextOop();
71 }
73 void do_size_t(size_t* p) {
74 // Assumes that size_t and pointers are the same size.
75 *p = (size_t)nextOop();
76 }
78 void do_tag(int tag) {
79 int old_tag;
80 do_int(&old_tag);
81 FileMapInfo::assert_mark(tag == old_tag);
82 }
84 void do_region(u_char* start, size_t size) {
85 assert((intptr_t)start % sizeof(oop) == 0, "bad alignment");
86 assert(size % sizeof(oop) == 0, "bad size");
87 do_tag((int)size);
88 while (size > 0) {
89 *(oop*)start = nextOop();
90 start += sizeof(oop);
91 size -= sizeof(oop);
92 }
93 }
95 bool reading() const { return true; }
96 };
99 // Read the oop and miscellaneous data from the shared file, and
100 // serialize it out to its various destinations.
102 void CompactingPermGenGen::initialize_oops() {
103 FileMapInfo *mapinfo = FileMapInfo::current_info();
105 char* buffer = mapinfo->region_base(md);
107 // Skip over (reserve space for) a list of addresses of C++ vtables
108 // for Klass objects. They get filled in later.
110 void** vtbl_list = (void**)buffer;
111 buffer += vtbl_list_size * sizeof(void*);
112 Universe::init_self_patching_vtbl_list(vtbl_list, vtbl_list_size);
114 // Skip over (reserve space for) dummy C++ vtables Klass objects.
115 // They are used as is.
117 intptr_t vtable_size = *(intptr_t*)buffer;
118 buffer += sizeof(intptr_t);
119 buffer += vtable_size;
121 // Skip the recorded symbols.
123 intptr_t total_symbol_size = *(intptr_t*)buffer;
124 buffer += sizeof(intptr_t) * 2;
125 buffer += total_symbol_size;
127 // Create the symbol table using the bucket array at this spot in the
128 // misc data space. Since the symbol table is often modified, this
129 // region (of mapped pages) will be copy-on-write.
131 int symbolTableLen = *(intptr_t*)buffer;
132 buffer += sizeof(intptr_t);
133 int number_of_entries = *(intptr_t*)buffer;
134 buffer += sizeof(intptr_t);
135 SymbolTable::create_table((HashtableBucket*)buffer, symbolTableLen,
136 number_of_entries);
137 buffer += symbolTableLen;
139 // Create the string table using the bucket array at this spot in the
140 // misc data space. Since the string table is often modified, this
141 // region (of mapped pages) will be copy-on-write.
143 int stringTableLen = *(intptr_t*)buffer;
144 buffer += sizeof(intptr_t);
145 number_of_entries = *(intptr_t*)buffer;
146 buffer += sizeof(intptr_t);
147 StringTable::create_table((HashtableBucket*)buffer, stringTableLen,
148 number_of_entries);
149 buffer += stringTableLen;
151 // Create the shared dictionary using the bucket array at this spot in
152 // the misc data space. Since the shared dictionary table is never
153 // modified, this region (of mapped pages) will be (effectively, if
154 // not explicitly) read-only.
156 int sharedDictionaryLen = *(intptr_t*)buffer;
157 buffer += sizeof(intptr_t);
158 number_of_entries = *(intptr_t*)buffer;
159 buffer += sizeof(intptr_t);
160 SystemDictionary::set_shared_dictionary((HashtableBucket*)buffer,
161 sharedDictionaryLen,
162 number_of_entries);
163 buffer += sharedDictionaryLen;
165 // Create the package info table using the bucket array at this spot in
166 // the misc data space. Since the package info table is never
167 // modified, this region (of mapped pages) will be (effectively, if
168 // not explicitly) read-only.
170 int pkgInfoLen = *(intptr_t*)buffer;
171 buffer += sizeof(intptr_t);
172 number_of_entries = *(intptr_t*)buffer;
173 buffer += sizeof(intptr_t);
174 ClassLoader::create_package_info_table((HashtableBucket*)buffer, pkgInfoLen,
175 number_of_entries);
176 buffer += pkgInfoLen;
177 ClassLoader::verify();
179 // The following data in the shared misc data region are the linked
180 // list elements (HashtableEntry objects) for the symbol table, string
181 // table, and shared dictionary. The heap objects refered to by the
182 // symbol table, string table, and shared dictionary are permanent and
183 // unmovable. Since new entries added to the string and symbol tables
184 // are always added at the beginning of the linked lists, THESE LINKED
185 // LIST ELEMENTS ARE READ-ONLY.
187 int len = *(intptr_t*)buffer; // skip over symbol table entries
188 buffer += sizeof(intptr_t);
189 buffer += len;
191 len = *(intptr_t*)buffer; // skip over string table entries
192 buffer += sizeof(intptr_t);
193 buffer += len;
195 len = *(intptr_t*)buffer; // skip over shared dictionary entries
196 buffer += sizeof(intptr_t);
197 buffer += len;
199 len = *(intptr_t*)buffer; // skip over package info table entries
200 buffer += sizeof(intptr_t);
201 buffer += len;
203 len = *(intptr_t*)buffer; // skip over package info table char[] arrays.
204 buffer += sizeof(intptr_t);
205 buffer += len;
207 oop* oop_array = (oop*)buffer;
208 ReadClosure rc(&oop_array);
209 serialize_oops(&rc);
210 }