1/*
2 * Copyright (c) 2014, 2019, 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
25#ifndef SHARE_JFR_UTILITIES_JFRALLOCATION_HPP
26#define SHARE_JFR_UTILITIES_JFRALLOCATION_HPP
27
28#include "memory/allocation.hpp"
29#include "services/memTracker.hpp"
30#include "utilities/exceptions.hpp"
31
32/*
33 * A subclass to the CHeapObj<mtTracing> allocator, useful for critical
34 * Jfr subsystems. Critical in this context means subsystems for which
35 * allocations are crucial to the bootstrap and initialization of Jfr.
36 * The default behaviour by a CHeapObj is to call vm_exit_out_of_memory()
37 * on allocation failure and this is problematic in combination with the
38 * Jfr on-demand, dynamic start at runtime, capability.
39 * We would not like a user dynamically starting Jfr to
40 * tear down the VM she is about to inspect as a side effect.
41 *
42 * This allocator uses the RETURN_NULL capabilities
43 * instead of calling vm_exit_out_of_memory() until Jfr is properly started.
44 * This allows for controlled behaviour on allocation failures during startup,
45 * which means we can take actions on failure, such as transactional rollback
46 * (deallocations and restorations).
47 * In addition, this allocator allows for easy hooking of memory
48 * allocations / deallocations for debugging purposes.
49 */
50
51class JfrCHeapObj : public CHeapObj<mtTracing> {
52 private:
53 static void on_memory_allocation(const void* allocation, size_t size);
54 static char* allocate_array_noinline(size_t elements, size_t element_size);
55
56 public:
57 NOINLINE void* operator new(size_t size) throw();
58 NOINLINE void* operator new (size_t size, const std::nothrow_t& nothrow_constant) throw();
59 NOINLINE void* operator new [](size_t size) throw();
60 NOINLINE void* operator new [](size_t size, const std::nothrow_t& nothrow_constant) throw();
61 void operator delete(void* p, size_t size);
62 void operator delete [] (void* p, size_t size);
63 static char* realloc_array(char* old, size_t size);
64 static void free(void* p, size_t size = 0);
65
66 template <class T>
67 static T* new_array(size_t size) {
68 T* const memory = (T*)allocate_array_noinline(size, sizeof(T));
69 on_memory_allocation(memory, sizeof(T) * size);
70 return memory;
71 }
72};
73
74#endif // SHARE_JFR_UTILITIES_JFRALLOCATION_HPP
75