Mercurial > hg > truffle
view src/share/vm/services/attachListener.hpp @ 452:00b023ae2d78
6722113: CMS: Incorrect overflow handling during precleaning of Reference lists
Summary: When we encounter marking stack overflow during precleaning of Reference lists, we were using the overflow list mechanism, which can cause problems on account of mutating the mark word of the header because of conflicts with mutator accesses and updates of that field. Instead we should use the usual mechanism for overflow handling in concurrent phases, namely dirtying of the card on which the overflowed object lies. Since precleaning effectively does a form of discovered list processing, albeit with discovery enabled, we needed to adjust some code to be correct in the face of interleaved processing and discovery.
Reviewed-by: apetrusenko, jcoomes
author | ysr |
---|---|
date | Thu, 20 Nov 2008 12:27:41 -0800 |
parents | a61af66fc99e |
children | c18cbe5936b8 |
line wrap: on
line source
/* * Copyright 2005-2006 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, * CA 95054 USA or visit www.sun.com if you need additional information or * have any questions. * */ // The AttachListener thread services a queue of operations that are enqueued // by client tools. Each operation is identified by a name and has up to 3 // arguments. The operation name is mapped to a function which performs the // operation. The function is called with an outputStream which is can use to // write any result data (for examples the properties command serializes // properties names and values to the output stream). When the function // complets the result value and any result data is returned to the client // tool. #ifndef SERVICES_KERNEL class AttachOperation; typedef jint (*AttachOperationFunction)(AttachOperation* op, outputStream* out); struct AttachOperationFunctionInfo { const char* name; AttachOperationFunction func; }; #endif // SERVICES_KERNEL class AttachListener: AllStatic { public: static void init() KERNEL_RETURN; static void abort() KERNEL_RETURN; // invoke to perform clean-up tasks when all clients detach static void detachall() KERNEL_RETURN; // indicates if the Attach Listener needs to be created at startup static bool init_at_startup() KERNEL_RETURN_(return false;); // indicates if we have a trigger to start the Attach Listener static bool is_init_trigger() KERNEL_RETURN_(return false;); #ifdef SERVICES_KERNEL static bool is_attach_supported() { return false; } #else // SERVICES_KERNEL private: static volatile bool _initialized; public: static bool is_initialized() { return _initialized; } static void set_initialized() { _initialized = true; } // indicates if this VM supports attach-on-demand static bool is_attach_supported() { return !DisableAttachMechanism; } // platform specific initialization static int pd_init(); // platform specific operation static AttachOperationFunctionInfo* pd_find_operation(const char* name); // platform specific flag change static jint pd_set_flag(AttachOperation* op, outputStream* out); // platform specific detachall static void pd_detachall(); // platform specific data dump static void pd_data_dump(); // dequeue the next operation static AttachOperation* dequeue(); #endif // SERVICES_KERNEL }; #ifndef SERVICES_KERNEL class AttachOperation: public CHeapObj { public: enum { name_length_max = 16, // maximum length of name arg_length_max = 1024, // maximum length of argument arg_count_max = 3 // maximum number of arguments }; // name of special operation that can be enqueued when all // clients detach static char* detachall_operation_name() { return (char*)"detachall"; } private: char _name[name_length_max+1]; char _arg[arg_count_max][arg_length_max+1]; public: const char* name() const { return _name; } // set the operation name void set_name(char* name) { assert(strlen(name) <= name_length_max, "exceeds maximum name length"); strcpy(_name, name); } // get an argument value const char* arg(int i) const { assert(i>=0 && i<arg_count_max, "invalid argument index"); return _arg[i]; } // set an argument value void set_arg(int i, char* arg) { assert(i>=0 && i<arg_count_max, "invalid argument index"); if (arg == NULL) { _arg[i][0] = '\0'; } else { assert(strlen(arg) <= arg_length_max, "exceeds maximum argument length"); strcpy(_arg[i], arg); } } // create an operation of a given name AttachOperation(char* name) { set_name(name); for (int i=0; i<arg_count_max; i++) { set_arg(i, NULL); } } // complete operation by sending result code and any result data to the client virtual void complete(jint result, bufferedStream* result_stream) = 0; }; #endif // SERVICES_KERNEL