src/share/vm/classfile/symbolTable.hpp
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rev 4551 : 8015237: Parallelize string table scanning during strong root processing
Summary: Parallelize the scanning of the intern string table by having each GC worker claim a given number of buckets. Changes were also reviewed by Per Liden <per.liden@oracle.com>.
Reviewed-by: tschatzl, stefank, twisti
@@ -1,7 +1,7 @@
/*
- * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation.
@@ -243,16 +243,23 @@
static StringTable* _the_table;
// Set if one bucket is out of balance due to hash algorithm deficiency
static bool _needs_rehashing;
+ // Claimed high water mark for parallel chunked scanning
+ static volatile int _parallel_claimed_idx;
+
static oop intern(Handle string_or_null, jchar* chars, int length, TRAPS);
oop basic_add(int index, Handle string_or_null, jchar* name, int len,
unsigned int hashValue, TRAPS);
oop lookup(int index, jchar* chars, int length, unsigned int hashValue);
+ // Apply the give oop closure to the entries to the buckets
+ // in the range [start_idx, end_idx).
+ static void buckets_do(OopClosure* f, int start_idx, int end_idx);
+
StringTable() : Hashtable<oop, mtSymbol>((int)StringTableSize,
sizeof (HashtableEntry<oop, mtSymbol>)) {}
StringTable(HashtableBucket<mtSymbol>* t, int number_of_entries)
: Hashtable<oop, mtSymbol>((int)StringTableSize, sizeof (HashtableEntry<oop, mtSymbol>), t,
@@ -276,13 +283,16 @@
// GC support
// Delete pointers to otherwise-unreachable objects.
static void unlink(BoolObjectClosure* cl);
- // Invoke "f->do_oop" on the locations of all oops in the table.
+ // Serially invoke "f->do_oop" on the locations of all oops in the table.
static void oops_do(OopClosure* f);
+ // Possibly parallel version of the above
+ static void possibly_parallel_oops_do(OopClosure* f);
+
// Hashing algorithm, used as the hash value used by the
// StringTable for bucket selection and comparison (stored in the
// HashtableEntry structures). This is used in the String.intern() method.
static unsigned int hash_string(const jchar* s, int len);
@@ -313,7 +323,10 @@
}
// Rehash the symbol table if it gets out of balance
static void rehash_table();
static bool needs_rehashing() { return _needs_rehashing; }
+
+ // Parallel chunked scanning
+ static void clear_parallel_claimed_index() { _parallel_claimed_idx = 0; }
};
#endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP