mirror of
https://github.com/openjdk/jdk.git
synced 2026-01-28 12:09:14 +00:00
355755d35d
Co-authored-by: Axel Boldt-Christmas <aboldtch@openjdk.org> Reviewed-by: coleenp, kbarrett, dholmes, aboldtch
64 lines
2.3 KiB
C++
64 lines
2.3 KiB
C++
/*
|
|
* Copyright (c) 2025, Oracle and/or its affiliates. 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_UTILITIES_SPINCRITICALSECTION_HPP
|
|
#define SHARE_UTILITIES_SPINCRITICALSECTION_HPP
|
|
|
|
#include "runtime/javaThread.hpp"
|
|
#include "runtime/safepointVerifiers.hpp"
|
|
#include "runtime/thread.hpp"
|
|
#include "utilities/macros.hpp"
|
|
|
|
// Ad-hoc mutual exclusion primitive: spin critical section,
|
|
// which employs a spin lock.
|
|
//
|
|
// We use this critical section only for low-contention code, and
|
|
// when it is know that the duration is short. To be used where
|
|
// we're concerned about native mutex_t or HotSpot Mutex:: latency.
|
|
// This class uses low-level leaf-lock primitives to implement
|
|
// synchronization and is not for general synchronization use.
|
|
// Should not be used in signal-handling contexts.
|
|
class SpinCriticalSection {
|
|
private:
|
|
// We use int type as 32-bit atomic operation is the most performant
|
|
// compared to smaller/larger types.
|
|
volatile int* const _lock;
|
|
DEBUG_ONLY(NoSafepointVerifier _nsv;)
|
|
|
|
static void spin_acquire(volatile int* Lock);
|
|
static void spin_release(volatile int* Lock);
|
|
public:
|
|
NONCOPYABLE(SpinCriticalSection);
|
|
SpinCriticalSection(volatile int* lock)
|
|
: _lock(lock)
|
|
DEBUG_ONLY(COMMA _nsv(Thread::current_or_null() != nullptr)) {
|
|
spin_acquire(_lock);
|
|
}
|
|
~SpinCriticalSection() {
|
|
spin_release(_lock);
|
|
}
|
|
};
|
|
|
|
#endif // SHARE_UTILITIES_SPINCRITICALSECTION_HPP
|