1 /* 2 * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 #ifndef SHARE_GC_SHARED_GCTHREADLOCALDATA_HPP 25 #define SHARE_GC_SHARED_GCTHREADLOCALDATA_HPP 26 27 #include "utilities/globalDefinitions.hpp" 28 29 // Thread local data area for GC-specific information. Each GC 30 // is free to decide the internal structure and contents of this 31 // area. It is represented as a 64-bit aligned opaque blob to 32 // avoid circular dependencies between Thread and all GCs. For 33 // the same reason, the size of the data area is hard coded to 34 // provide enough space for all current GCs. Adjust the size if 35 // needed, but avoid making it excessively large as it adds to 36 // the memory overhead of creating a thread. 37 // 38 // Use Thread::gc_data<T>() to access the data, where T is the 39 // GC-specific type describing the structure of the data. GCs 40 // should consider placing frequently accessed fields first in 41 // T, so that field offsets relative to Thread are small, which 42 // often allows for a more compact instruction encoding. 43 typedef uint64_t GCThreadLocalData[14]; // 112 bytes 44 45 #endif // SHARE_GC_SHARED_GCTHREADLOCALDATA_HPP