--- /dev/null 2019-01-28 17:48:07.000000000 +0800 +++ new/src/share/vm/jfr/utilities/jfrAllocation.hpp 2019-01-28 17:48:07.000000000 +0800 @@ -0,0 +1,74 @@ +/* + * Copyright (c) 2014, 2019, 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_JFR_UTILITIES_JFRALLOCATION_HPP +#define SHARE_VM_JFR_UTILITIES_JFRALLOCATION_HPP + +#include "memory/allocation.hpp" +#include "services/memTracker.hpp" +#include "utilities/exceptions.hpp" + +/* + * A subclass to the CHeapObj allocator, useful for critical + * Jfr subsystems. Critical in this context means subsystems for which + * allocations are crucial to the bootstrap and initialization of Jfr. + * The default behaviour by a CHeapObj is to call vm_exit_out_of_memory() + * on allocation failure and this is problematic in combination with the + * Jfr on-demand, dynamic start at runtime, capability. + * We would not like a user dynamically starting Jfr to + * tear down the VM she is about to inspect as a side effect. + * + * This allocator uses the RETURN_NULL capabilities + * instead of calling vm_exit_out_of_memory() until Jfr is properly started. + * This allows for controlled behaviour on allocation failures during startup, + * which means we can take actions on failure, such as transactional rollback + * (deallocations and restorations). + * In addition, this allocator allows for easy hooking of memory + * allocations / deallocations for debugging purposes. + */ + +class JfrCHeapObj : public CHeapObj { + private: + static void on_memory_allocation(const void* allocation, size_t size); + static char* allocate_array_noinline(size_t elements, size_t element_size); + + public: + _NOINLINE_ void* operator new(size_t size) throw(); + _NOINLINE_ void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw(); + _NOINLINE_ void* operator new [](size_t size) throw(); + _NOINLINE_ void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw(); + void operator delete(void* p, size_t size); + void operator delete [] (void* p, size_t size); + static char* realloc_array(char* old, size_t size); + static void free(void* p, size_t size = 0); + + template + static T* new_array(size_t size) { + T* const memory = (T*)allocate_array_noinline(size, sizeof(T)); + on_memory_allocation(memory, sizeof(T) * size); + return memory; + } +}; + +#endif // SHARE_VM_JFR_UTILITIES_JFRALLOCATION_HPP