1 /*
   2  * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
   3  *
   4  * This code is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 only, as
   6  * published by the Free Software Foundation.
   7  *
   8  * This code is distributed in the hope that it will be useful, but WITHOUT
   9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * version 2 for more details (a copy is included in the LICENSE file that
  12  * accompanied this code).
  13  *
  14  * You should have received a copy of the GNU General Public License version
  15  * 2 along with this work; if not, write to the Free Software Foundation,
  16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  19  * or visit www.oracle.com if you need additional information or have any
  20  * questions.
  21  *
  22  */
  23 
  24 #include "precompiled.hpp"
  25 #include "services/shenandoahMemoryPool.hpp"
  26 
  27 ShenandoahMemoryPool::ShenandoahMemoryPool(ShenandoahHeap* heap) :
  28         CollectedMemoryPool("Shenandoah",
  29                             MemoryPool::Heap,
  30                             heap->initial_capacity(),
  31                             heap->max_capacity(),
  32                             true /* support_usage_threshold */),
  33                             _heap(heap) {}
  34 
  35 MemoryUsage ShenandoahMemoryPool::get_memory_usage() {
  36   size_t initial   = initial_size();
  37   size_t max       = max_size();
  38   size_t used      = used_in_bytes();
  39   size_t committed = _heap->committed();
  40 
  41   // These asserts can never fail: max is stable, and all updates to other values never overflow max.
  42   assert(initial <= max,    err_msg("initial: "   SIZE_FORMAT ", max: "       SIZE_FORMAT, initial,   max));
  43   assert(used <= max,       err_msg("used: "      SIZE_FORMAT ", max: "       SIZE_FORMAT, used,      max));
  44   assert(committed <= max,  err_msg("committed: " SIZE_FORMAT ", max: "       SIZE_FORMAT, committed, max));
  45   assert(used <= committed, err_msg("used: "      SIZE_FORMAT ", committed: " SIZE_FORMAT, used,      committed));
  46 
  47   // Committed and used are updated concurrently and independently. They can momentarily break
  48   // the assert below, which would also fail in downstream code. To avoid that, adjust values
  49   // to make sense under the race. See JDK-8207200.
  50   committed = MAX2(used, committed);
  51 
  52   return MemoryUsage(initial, used, committed, max);
  53 }