ceph/src/seastar/include/seastar/core/shared_ptr_debug_helper.hh

   1 /*
   2  * This file is open source software, licensed to you under the terms
   3  * of the Apache License, Version 2.0 (the "License").  See the NOTICE file
   4  * distributed with this work for additional information regarding copyright
   5  * ownership.  You may not use this file except in compliance with the License.
   6  *
   7  * You may obtain a copy of the License at
   8  *
   9  *   http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing,
  12  * software distributed under the License is distributed on an
  13  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  14  * KIND, either express or implied.  See the License for the
  15  * specific language governing permissions and limitations
  16  * under the License.
  17  */
  18 /*
  19  * Copyright (C) 2015 Cloudius Systems, Ltd.
  20  */
  21
  22 #pragma once
  23
  24 #ifdef SEASTAR_DEBUG_SHARED_PTR
  25
  26 #include <thread>
  27 #include <cassert>
  28
  29 #include <seastar/core/on_internal_error.hh>
  30
  31 namespace seastar {
  32
  33 extern logger seastar_logger;
  34
  35 // A counter that is only comfortable being incremented on the cpu
  36 // it was created on.  Useful for verifying that a shared_ptr
  37 // or lw_shared_ptr isn't misued across cores.
  38 class debug_shared_ptr_counter_type {
  39     long _counter = 0;
  40     std::thread::id _cpu = std::this_thread::get_id();
  41 public:
  42     debug_shared_ptr_counter_type(long x) noexcept : _counter(x) {}
  43     operator long() const {
  44         check();
  45         return _counter;
  46     }
  47     debug_shared_ptr_counter_type& operator++() {
  48         check();
  49         ++_counter;
  50         return *this;
  51     }
  52     long operator++(int) {
  53         check();
  54         return _counter++;
  55     }
  56     debug_shared_ptr_counter_type& operator--() {
  57         check();
  58         --_counter;
  59         return *this;
  60     }
  61     long operator--(int) {
  62         check();
  63         return _counter--;
  64     }
  65 private:
  66     void check() const {
  67         if (__builtin_expect(_cpu != std::this_thread::get_id(), false)) {
  68             on_fatal_internal_error(seastar_logger, "shared_ptr accessed on non-owner cpu");
  69         }
  70     }
  71 };
  72
  73 }
  74
  75 #endif
  76