1 /*

     2  * Copyright (c) 2014, 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 

    25 #ifndef SHARE_VM_JFR_UTILITIES_JFRALLOCATION_HPP

    26 #define SHARE_VM_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 

    51 class 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_VM_JFR_UTILITIES_JFRALLOCATION_HPP