Mercurial > hg > graal-compiler
view src/share/vm/oops/symbolOop.hpp @ 2149:7e37af9d69ef
7011379: G1: overly long concurrent marking cycles
Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads.
Reviewed-by: johnc, ysr
author | tonyp |
---|---|
date | Wed, 19 Jan 2011 09:35:17 -0500 |
parents | f95d63e2154a |
children |
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/* * Copyright (c) 1997, 2010, 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. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_OOPS_SYMBOLOOP_HPP #define SHARE_VM_OOPS_SYMBOLOOP_HPP #include "oops/typeArrayOop.hpp" #include "utilities/utf8.hpp" // A symbolOop is a canonicalized string. // All symbolOops reside in global symbolTable. // See oopFactory::new_symbol for how to allocate a symbolOop class symbolOopDesc : public oopDesc { friend class VMStructs; private: unsigned short _length; // number of UTF8 characters in the symbol jbyte _body[1]; enum { // max_symbol_length is constrained by type of _length max_symbol_length = (1 << 16) -1 }; public: // Low-level access (used with care, since not GC-safe) jbyte* base() { return &_body[0]; } // Returns the largest size symbol we can safely hold. static int max_length() { return max_symbol_length; } static int object_size(int length) { int size = header_size() + (sizeof(unsigned short) + length + HeapWordSize - 1) / HeapWordSize; return align_object_size(size); } int object_size() { return object_size(utf8_length()); } int byte_at(int index) const { assert(index >=0 && index < _length, "symbol index overflow"); return ((symbolOopDesc*)this)->base()[index]; } void byte_at_put(int index, int value) { assert(index >=0 && index < _length, "symbol index overflow"); ((symbolOopDesc*)this)->base()[index] = value; } jbyte* bytes() { return base(); } int utf8_length() const { return _length; } void set_utf8_length(int len) { _length = len; } // Compares the symbol with a string. bool equals(const char* str, int len) const; bool equals(const char* str) const { return equals(str, (int) strlen(str)); } // Tests if the symbol starts with the given prefix. bool starts_with(const char* prefix, int len) const; bool starts_with(const char* prefix) const { return starts_with(prefix, (int) strlen(prefix)); } // Tests if the symbol starts with the given prefix. int index_of_at(int i, const char* str, int len) const; int index_of_at(int i, const char* str) const { return index_of_at(i, str, (int) strlen(str)); } // Three-way compare for sorting; returns -1/0/1 if receiver is </==/> than arg // note that the ordering is not alfabetical inline int fast_compare(symbolOop other) const; // Returns receiver converted to null-terminated UTF-8 string; string is // allocated in resource area, or in the char buffer provided by caller. char* as_C_string() const; char* as_C_string(char* buf, int size) const; // Use buf if needed buffer length is <= size. char* as_C_string_flexible_buffer(Thread* t, char* buf, int size) const; // Returns a null terminated utf8 string in a resource array char* as_utf8() const { return as_C_string(); } char* as_utf8_flexible_buffer(Thread* t, char* buf, int size) const { return as_C_string_flexible_buffer(t, buf, size); } jchar* as_unicode(int& length) const; // Treating this symbol as a class name, returns the Java name for the class. // String is allocated in resource area if buffer is not provided. // See Klass::external_name() const char* as_klass_external_name() const; const char* as_klass_external_name(char* buf, int size) const; bool object_is_parsable() const { return (utf8_length() > 0 || (oop)this == Universe::emptySymbol()); } // Printing void print_symbol_on(outputStream* st = NULL); }; // Note: this comparison is used for vtable sorting only; it doesn't matter // what order it defines, as long as it is a total, time-invariant order // Since symbolOops are in permSpace, their relative order in memory never changes, // so use address comparison for speed int symbolOopDesc::fast_compare(symbolOop other) const { return (((uintptr_t)this < (uintptr_t)other) ? -1 : ((uintptr_t)this == (uintptr_t) other) ? 0 : 1); } #endif // SHARE_VM_OOPS_SYMBOLOOP_HPP