1 /*
 2  * Copyright (c) 2013, 2019, Red Hat, Inc. 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 #include "precompiled.hpp"
26 #include "gc/shenandoah/shenandoahMemoryPool.hpp"
27 
28 ShenandoahMemoryPool::ShenandoahMemoryPool(ShenandoahHeap* heap) :
29         CollectedMemoryPool("Shenandoah",
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,    "initial: "   SIZE_FORMAT ", max: "       SIZE_FORMAT, initial,   max);
43   assert(used <= max,       "used: "      SIZE_FORMAT ", max: "       SIZE_FORMAT, used,      max);
44   assert(committed <= max,  "committed: " SIZE_FORMAT ", max: "       SIZE_FORMAT, committed, max);
45 
46   // Committed and used are updated concurrently and independently. They can momentarily break
47   // the assert below, which would also fail in downstream code. To avoid that, adjust values
48   // to make sense under the race. See JDK-8207200.
49   committed = MAX2(used, committed);
50   assert(used <= committed, "used: "      SIZE_FORMAT ", committed: " SIZE_FORMAT, used,      committed);
51 
52   return MemoryUsage(initial, used, committed, max);
53 }