mirror of
https://github.com/openjdk/jdk.git
synced 2026-05-12 06:29:37 +00:00
85 lines
3.3 KiB
C++
85 lines
3.3 KiB
C++
/*
|
|
* Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
|
|
* Copyright (c) 2020 SAP SE. All rights reserved.
|
|
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
|
|
*
|
|
* This code is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License version 2 only, as
|
|
* published by the Free Software Foundation.
|
|
*
|
|
* This code is distributed in the hope that it will be useful, but WITHOUT
|
|
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
|
|
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
|
|
* version 2 for more details (a copy is included in the LICENSE file that
|
|
* accompanied this code).
|
|
*
|
|
* You should have received a copy of the GNU General Public License version
|
|
* 2 along with this work; if not, write to the Free Software Foundation,
|
|
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
|
|
*
|
|
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
|
|
* or visit www.oracle.com if you need additional information or have any
|
|
* questions.
|
|
*
|
|
*/
|
|
|
|
#ifndef SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP
|
|
#define SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP
|
|
|
|
#include "memory/allocation.hpp"
|
|
#include "memory/metaspace/counters.hpp"
|
|
|
|
namespace metaspace {
|
|
|
|
// The CommitLimiter encapsulates a limit we may want to impose on how much
|
|
// memory can be committed. This is a matter of separation of concerns:
|
|
//
|
|
// In metaspace, we have two limits to committing memory: the absolute limit,
|
|
// MaxMetaspaceSize; and the GC threshold. In both cases an allocation should
|
|
// fail if it would require committing memory and hit one of these limits.
|
|
//
|
|
// However, the actual Metaspace allocator is a generic one and this
|
|
// GC- and classloading specific logic should be kept separate. Therefore
|
|
// it is hidden inside this interface.
|
|
//
|
|
// This allows us to:
|
|
// - more easily write tests for metaspace, by providing a different implementation
|
|
// of the commit limiter, thus keeping test logic separate from VM state.
|
|
// - (potentially) use the metaspace for things other than class metadata,
|
|
// where different commit rules would apply.
|
|
//
|
|
class CommitLimiter : public CHeapObj<mtMetaspace> {
|
|
|
|
// Counts total words committed for metaspace
|
|
SizeCounter _cnt;
|
|
|
|
// Purely for testing purposes: cap, in words.
|
|
const size_t _cap;
|
|
|
|
public:
|
|
|
|
// Create a commit limiter. This is only useful for testing, with a cap != 0,
|
|
// since normal code should use the global commit limiter.
|
|
// If cap != 0 (word size), the cap replaces the internal logic of limiting.
|
|
CommitLimiter(size_t cap = 0) : _cnt(), _cap(cap) {}
|
|
|
|
// Returns the size, in words, by which we may expand the metaspace committed area without:
|
|
// - _cap == 0: hitting GC threshold or the MaxMetaspaceSize
|
|
// - _cap > 0: hitting cap (this is just for testing purposes)
|
|
size_t possible_expansion_words() const;
|
|
|
|
void increase_committed(size_t word_size) { _cnt.increment_by(word_size); }
|
|
void decrease_committed(size_t word_size) { _cnt.decrement_by(word_size); }
|
|
|
|
size_t committed_words() const { return _cnt.get(); }
|
|
size_t cap() const { return _cap; }
|
|
|
|
// Returns the global metaspace commit counter
|
|
static CommitLimiter* globalLimiter();
|
|
|
|
};
|
|
|
|
} // namespace metaspace
|
|
|
|
#endif // SHARE_MEMORY_METASPACE_COMMITLIMITER_HPP
|