src/hotspot/share/gc/shenandoah/shenandoahMemoryPool.cpp
author shade
Thu, 21 Feb 2019 15:52:42 +0100
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8219524: Shenandoah misreports "committed" size in MemoryMXBean Reviewed-by: rkennke, zgu
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/*
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 * Copyright (c) 2013, 2018, Red Hat, Inc. All rights reserved.
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 *
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 * This code is free software; you can redistribute it and/or modify it
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 * under the terms of the GNU General Public License version 2 only, as
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 * published by the Free Software Foundation.
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 *
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 * This code is distributed in the hope that it will be useful, but WITHOUT
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 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
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 * version 2 for more details (a copy is included in the LICENSE file that
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 * accompanied this code).
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 *
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 * You should have received a copy of the GNU General Public License version
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 * 2 along with this work; if not, write to the Free Software Foundation,
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 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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 *
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 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * or visit www.oracle.com if you need additional information or have any
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 * questions.
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 *
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 */
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#include "precompiled.hpp"
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#include "gc/shenandoah/shenandoahMemoryPool.hpp"
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ShenandoahMemoryPool::ShenandoahMemoryPool(ShenandoahHeap* heap) :
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        CollectedMemoryPool("Shenandoah",
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                            heap->initial_capacity(),
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                            heap->max_capacity(),
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                            true /* support_usage_threshold */),
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                            _heap(heap) {}
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MemoryUsage ShenandoahMemoryPool::get_memory_usage() {
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  size_t initial   = initial_size();
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  size_t max       = max_size();
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  size_t used      = used_in_bytes();
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  size_t committed = _heap->committed();
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  // These asserts can never fail: max is stable, and all updates to other values never overflow max.
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  assert(initial <= max,    "initial: "   SIZE_FORMAT ", max: "       SIZE_FORMAT, initial,   max);
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  assert(used <= max,       "used: "      SIZE_FORMAT ", max: "       SIZE_FORMAT, used,      max);
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  assert(committed <= max,  "committed: " SIZE_FORMAT ", max: "       SIZE_FORMAT, committed, max);
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  // Committed and used are updated concurrently and independently. They can momentarily break
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  // the assert below, which would also fail in downstream code. To avoid that, adjust values
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  // to make sense under the race. See JDK-8207200.
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  committed = MAX2(used, committed);
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  assert(used <= committed, "used: "      SIZE_FORMAT ", committed: " SIZE_FORMAT, used,      committed);
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  return MemoryUsage(initial, used, committed, max);
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}