libstdc++-v3/testsuite/20_util/unsynchronized_pool_resource/allocate-max-chunks.cc

   1 // Copyright (C) 2018-2020 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-options "-std=gnu++17" }
  19 // { dg-do run { target c++17 } }
  20
  21 #include <memory_resource>
  22 #include <testsuite_hooks.h>
  23
  24 struct custom_mr : std::pmr::memory_resource
  25 {
  26   custom_mr(std::size_t max) : max(max) { }
  27
  28   bool reached_max = false;
  29
  30 private:
  31   std::size_t max;
  32   std::size_t count = 0;
  33
  34   void* do_allocate(std::size_t b, std::size_t a)
  35   {
  36     if (b >= max)
  37       reached_max = true;
  38     count += b;
  39     if (count > (18 * 1024 * 1024))
  40       // Something went wrong, should not need to allocate this much.
  41       throw std::bad_alloc();
  42     return std::pmr::new_delete_resource()->allocate(b, a);
  43   }
  44
  45   void do_deallocate(void* p, std::size_t b, std::size_t a)
  46   { std::pmr::new_delete_resource()->deallocate(p, b, a); }
  47
  48   bool do_is_equal(const memory_resource& r) const noexcept
  49   { return false; }
  50 };
  51
  52 void
  53 test01()
  54 {
  55   // Only going to allocate blocks of this size:
  56   const std::size_t block_size = 8;
  57   std::pmr::pool_options opts{};
  58   // Use maximum allowed number of blocks per chunk:
  59   opts.max_blocks_per_chunk = (std::size_t)-1;
  60   opts.largest_required_pool_block = block_size;
  61   {
  62     std::pmr::unsynchronized_pool_resource r(opts);
  63     // Get the real max_blocks_per_chunk that will be used:
  64     opts = r.options();
  65     // Sanity test in case chunk::max_blocks_per_chunk() changes,
  66     // as that could make this test take much longer to run:
  67     VERIFY( opts.max_blocks_per_chunk <= (1 << 19) );
  68   }
  69   custom_mr c(block_size * opts.max_blocks_per_chunk);
  70   std::pmr::unsynchronized_pool_resource r(opts, &c);
  71   // Keep allocating from the pool until reaching the maximum chunk size:
  72   while (!c.reached_max)
  73     (void) r.allocate(block_size, 1);
  74   c.reached_max = false;
  75   // Now fill that maximally-sized chunk
  76   // (this used to go into an infinite loop ):
  77   for (std::size_t i = 0; i < opts.max_blocks_per_chunk; ++i)
  78     (void) r.allocate(block_size, 1);
  79   // Should have filled the maximally-sized chunk and allocated another
  80   // maximally-sized chunk from upstream:
  81   VERIFY( c.reached_max );
  82 }
  83
  84 int
  85 main()
  86 {
  87   test01();
  88 }