Thu, 11 Feb 2010 15:52:19 -0800
6923991: G1: improve scalability of RSet scanning
Summary: Implemented block-based work stealing. Moved copying during the rset scanning phase to the main copying phase. Made the size of rset table depend on the region size.
Reviewed-by: apetrusenko, tonyp
duke@435 | 1 | /* |
duke@435 | 2 | * Copyright 2003-2005 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | // This is a generic hashtable, designed to be used for the symbol |
duke@435 | 26 | // and string tables. |
duke@435 | 27 | // |
duke@435 | 28 | // It is implemented as an open hash table with a fixed number of buckets. |
duke@435 | 29 | // |
duke@435 | 30 | // %note: |
duke@435 | 31 | // - TableEntrys are allocated in blocks to reduce the space overhead. |
duke@435 | 32 | |
duke@435 | 33 | |
duke@435 | 34 | |
duke@435 | 35 | class BasicHashtableEntry : public CHeapObj { |
duke@435 | 36 | friend class VMStructs; |
duke@435 | 37 | private: |
duke@435 | 38 | unsigned int _hash; // 32-bit hash for item |
duke@435 | 39 | |
duke@435 | 40 | // Link to next element in the linked list for this bucket. EXCEPT |
duke@435 | 41 | // bit 0 set indicates that this entry is shared and must not be |
duke@435 | 42 | // unlinked from the table. Bit 0 is set during the dumping of the |
duke@435 | 43 | // archive. Since shared entries are immutable, _next fields in the |
duke@435 | 44 | // shared entries will not change. New entries will always be |
duke@435 | 45 | // unshared and since pointers are align, bit 0 will always remain 0 |
duke@435 | 46 | // with no extra effort. |
duke@435 | 47 | BasicHashtableEntry* _next; |
duke@435 | 48 | |
duke@435 | 49 | // Windows IA64 compiler requires subclasses to be able to access these |
duke@435 | 50 | protected: |
duke@435 | 51 | // Entry objects should not be created, they should be taken from the |
duke@435 | 52 | // free list with BasicHashtable.new_entry(). |
duke@435 | 53 | BasicHashtableEntry() { ShouldNotReachHere(); } |
duke@435 | 54 | // Entry objects should not be destroyed. They should be placed on |
duke@435 | 55 | // the free list instead with BasicHashtable.free_entry(). |
duke@435 | 56 | ~BasicHashtableEntry() { ShouldNotReachHere(); } |
duke@435 | 57 | |
duke@435 | 58 | public: |
duke@435 | 59 | |
duke@435 | 60 | unsigned int hash() const { return _hash; } |
duke@435 | 61 | void set_hash(unsigned int hash) { _hash = hash; } |
duke@435 | 62 | unsigned int* hash_addr() { return &_hash; } |
duke@435 | 63 | |
duke@435 | 64 | static BasicHashtableEntry* make_ptr(BasicHashtableEntry* p) { |
duke@435 | 65 | return (BasicHashtableEntry*)((intptr_t)p & -2); |
duke@435 | 66 | } |
duke@435 | 67 | |
duke@435 | 68 | BasicHashtableEntry* next() const { |
duke@435 | 69 | return make_ptr(_next); |
duke@435 | 70 | } |
duke@435 | 71 | |
duke@435 | 72 | void set_next(BasicHashtableEntry* next) { |
duke@435 | 73 | _next = next; |
duke@435 | 74 | } |
duke@435 | 75 | |
duke@435 | 76 | BasicHashtableEntry** next_addr() { |
duke@435 | 77 | return &_next; |
duke@435 | 78 | } |
duke@435 | 79 | |
duke@435 | 80 | bool is_shared() const { |
duke@435 | 81 | return ((intptr_t)_next & 1) != 0; |
duke@435 | 82 | } |
duke@435 | 83 | |
duke@435 | 84 | void set_shared() { |
duke@435 | 85 | _next = (BasicHashtableEntry*)((intptr_t)_next | 1); |
duke@435 | 86 | } |
duke@435 | 87 | }; |
duke@435 | 88 | |
duke@435 | 89 | |
duke@435 | 90 | |
duke@435 | 91 | class HashtableEntry : public BasicHashtableEntry { |
duke@435 | 92 | friend class VMStructs; |
duke@435 | 93 | private: |
duke@435 | 94 | oop _literal; // ref to item in table. |
duke@435 | 95 | |
duke@435 | 96 | public: |
duke@435 | 97 | // Literal |
duke@435 | 98 | oop literal() const { return _literal; } |
duke@435 | 99 | oop* literal_addr() { return &_literal; } |
duke@435 | 100 | void set_literal(oop s) { _literal = s; } |
duke@435 | 101 | |
duke@435 | 102 | HashtableEntry* next() const { |
duke@435 | 103 | return (HashtableEntry*)BasicHashtableEntry::next(); |
duke@435 | 104 | } |
duke@435 | 105 | HashtableEntry** next_addr() { |
duke@435 | 106 | return (HashtableEntry**)BasicHashtableEntry::next_addr(); |
duke@435 | 107 | } |
duke@435 | 108 | }; |
duke@435 | 109 | |
duke@435 | 110 | |
duke@435 | 111 | |
duke@435 | 112 | class HashtableBucket : public CHeapObj { |
duke@435 | 113 | friend class VMStructs; |
duke@435 | 114 | private: |
duke@435 | 115 | // Instance variable |
duke@435 | 116 | BasicHashtableEntry* _entry; |
duke@435 | 117 | |
duke@435 | 118 | public: |
duke@435 | 119 | // Accessing |
duke@435 | 120 | void clear() { _entry = NULL; } |
duke@435 | 121 | |
duke@435 | 122 | // The following methods use order access methods to avoid race |
duke@435 | 123 | // conditions in multiprocessor systems. |
duke@435 | 124 | BasicHashtableEntry* get_entry() const; |
duke@435 | 125 | void set_entry(BasicHashtableEntry* l); |
duke@435 | 126 | |
duke@435 | 127 | // The following method is not MT-safe and must be done under lock. |
duke@435 | 128 | BasicHashtableEntry** entry_addr() { return &_entry; } |
duke@435 | 129 | }; |
duke@435 | 130 | |
duke@435 | 131 | |
duke@435 | 132 | class BasicHashtable : public CHeapObj { |
duke@435 | 133 | friend class VMStructs; |
duke@435 | 134 | |
duke@435 | 135 | public: |
duke@435 | 136 | BasicHashtable(int table_size, int entry_size); |
duke@435 | 137 | BasicHashtable(int table_size, int entry_size, |
duke@435 | 138 | HashtableBucket* buckets, int number_of_entries); |
duke@435 | 139 | |
duke@435 | 140 | // Sharing support. |
duke@435 | 141 | void copy_buckets(char** top, char* end); |
duke@435 | 142 | void copy_table(char** top, char* end); |
duke@435 | 143 | |
duke@435 | 144 | // Bucket handling |
duke@435 | 145 | int hash_to_index(unsigned int full_hash) { |
duke@435 | 146 | int h = full_hash % _table_size; |
duke@435 | 147 | assert(h >= 0 && h < _table_size, "Illegal hash value"); |
duke@435 | 148 | return h; |
duke@435 | 149 | } |
duke@435 | 150 | |
duke@435 | 151 | // Reverse the order of elements in each of the buckets. |
duke@435 | 152 | void reverse(); |
duke@435 | 153 | |
duke@435 | 154 | private: |
duke@435 | 155 | // Instance variables |
duke@435 | 156 | int _table_size; |
duke@435 | 157 | HashtableBucket* _buckets; |
duke@435 | 158 | BasicHashtableEntry* _free_list; |
duke@435 | 159 | char* _first_free_entry; |
duke@435 | 160 | char* _end_block; |
duke@435 | 161 | int _entry_size; |
duke@435 | 162 | int _number_of_entries; |
duke@435 | 163 | |
duke@435 | 164 | protected: |
duke@435 | 165 | |
duke@435 | 166 | #ifdef ASSERT |
duke@435 | 167 | int _lookup_count; |
duke@435 | 168 | int _lookup_length; |
duke@435 | 169 | void verify_lookup_length(double load); |
duke@435 | 170 | #endif |
duke@435 | 171 | |
duke@435 | 172 | void initialize(int table_size, int entry_size, int number_of_entries); |
duke@435 | 173 | |
duke@435 | 174 | // Accessor |
duke@435 | 175 | int entry_size() const { return _entry_size; } |
duke@435 | 176 | int table_size() { return _table_size; } |
duke@435 | 177 | |
duke@435 | 178 | // The following method is MT-safe and may be used with caution. |
duke@435 | 179 | BasicHashtableEntry* bucket(int i); |
duke@435 | 180 | |
duke@435 | 181 | // The following method is not MT-safe and must be done under lock. |
duke@435 | 182 | BasicHashtableEntry** bucket_addr(int i) { return _buckets[i].entry_addr(); } |
duke@435 | 183 | |
duke@435 | 184 | // Table entry management |
duke@435 | 185 | BasicHashtableEntry* new_entry(unsigned int hashValue); |
duke@435 | 186 | |
duke@435 | 187 | public: |
duke@435 | 188 | void set_entry(int index, BasicHashtableEntry* entry); |
duke@435 | 189 | |
duke@435 | 190 | void add_entry(int index, BasicHashtableEntry* entry); |
duke@435 | 191 | |
duke@435 | 192 | void free_entry(BasicHashtableEntry* entry); |
duke@435 | 193 | |
duke@435 | 194 | int number_of_entries() { return _number_of_entries; } |
duke@435 | 195 | |
duke@435 | 196 | void verify() PRODUCT_RETURN; |
duke@435 | 197 | }; |
duke@435 | 198 | |
duke@435 | 199 | |
duke@435 | 200 | class Hashtable : public BasicHashtable { |
duke@435 | 201 | friend class VMStructs; |
duke@435 | 202 | |
duke@435 | 203 | public: |
duke@435 | 204 | Hashtable(int table_size, int entry_size) |
duke@435 | 205 | : BasicHashtable(table_size, entry_size) { } |
duke@435 | 206 | |
duke@435 | 207 | Hashtable(int table_size, int entry_size, |
duke@435 | 208 | HashtableBucket* buckets, int number_of_entries) |
duke@435 | 209 | : BasicHashtable(table_size, entry_size, buckets, number_of_entries) { } |
duke@435 | 210 | |
duke@435 | 211 | // Invoke "f->do_oop" on the locations of all oops in the table. |
duke@435 | 212 | void oops_do(OopClosure* f); |
duke@435 | 213 | |
duke@435 | 214 | // Debugging |
duke@435 | 215 | void print() PRODUCT_RETURN; |
duke@435 | 216 | |
duke@435 | 217 | // GC support |
duke@435 | 218 | // Delete pointers to otherwise-unreachable objects. |
duke@435 | 219 | void unlink(BoolObjectClosure* cl); |
duke@435 | 220 | |
duke@435 | 221 | // Reverse the order of elements in each of the buckets. Hashtable |
duke@435 | 222 | // entries which refer to objects at a lower address than 'boundary' |
duke@435 | 223 | // are separated from those which refer to objects at higher |
duke@435 | 224 | // addresses, and appear first in the list. |
duke@435 | 225 | void reverse(void* boundary = NULL); |
duke@435 | 226 | |
duke@435 | 227 | protected: |
duke@435 | 228 | |
duke@435 | 229 | static unsigned int hash_symbol(const char* s, int len); |
duke@435 | 230 | |
duke@435 | 231 | unsigned int compute_hash(symbolHandle name) { |
duke@435 | 232 | return (unsigned int) name->identity_hash(); |
duke@435 | 233 | } |
duke@435 | 234 | |
duke@435 | 235 | int index_for(symbolHandle name) { |
duke@435 | 236 | return hash_to_index(compute_hash(name)); |
duke@435 | 237 | } |
duke@435 | 238 | |
duke@435 | 239 | // Table entry management |
duke@435 | 240 | HashtableEntry* new_entry(unsigned int hashValue, oop obj); |
duke@435 | 241 | |
duke@435 | 242 | // The following method is MT-safe and may be used with caution. |
duke@435 | 243 | HashtableEntry* bucket(int i) { |
duke@435 | 244 | return (HashtableEntry*)BasicHashtable::bucket(i); |
duke@435 | 245 | } |
duke@435 | 246 | |
duke@435 | 247 | // The following method is not MT-safe and must be done under lock. |
duke@435 | 248 | HashtableEntry** bucket_addr(int i) { |
duke@435 | 249 | return (HashtableEntry**)BasicHashtable::bucket_addr(i); |
duke@435 | 250 | } |
duke@435 | 251 | }; |
duke@435 | 252 | |
duke@435 | 253 | |
duke@435 | 254 | // Verions of hashtable where two handles are used to compute the index. |
duke@435 | 255 | |
duke@435 | 256 | class TwoOopHashtable : public Hashtable { |
duke@435 | 257 | friend class VMStructs; |
duke@435 | 258 | protected: |
duke@435 | 259 | TwoOopHashtable(int table_size, int entry_size) |
duke@435 | 260 | : Hashtable(table_size, entry_size) {} |
duke@435 | 261 | |
duke@435 | 262 | TwoOopHashtable(int table_size, int entry_size, HashtableBucket* t, |
duke@435 | 263 | int number_of_entries) |
duke@435 | 264 | : Hashtable(table_size, entry_size, t, number_of_entries) {} |
duke@435 | 265 | |
duke@435 | 266 | public: |
duke@435 | 267 | unsigned int compute_hash(symbolHandle name, Handle loader) { |
duke@435 | 268 | // Be careful with identity_hash(), it can safepoint and if this |
duke@435 | 269 | // were one expression, the compiler could choose to unhandle each |
duke@435 | 270 | // oop before calling identity_hash() for either of them. If the first |
duke@435 | 271 | // causes a GC, the next would fail. |
duke@435 | 272 | unsigned int name_hash = name->identity_hash(); |
duke@435 | 273 | unsigned int loader_hash = loader.is_null() ? 0 : loader->identity_hash(); |
duke@435 | 274 | return name_hash ^ loader_hash; |
duke@435 | 275 | } |
duke@435 | 276 | |
duke@435 | 277 | int index_for(symbolHandle name, Handle loader) { |
duke@435 | 278 | return hash_to_index(compute_hash(name, loader)); |
duke@435 | 279 | } |
duke@435 | 280 | }; |