71 lines
2.6 KiB
C++
71 lines
2.6 KiB
C++
/*
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* Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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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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#ifndef SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP
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#define SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP
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#include "runtime/atomic.hpp"
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#include "runtime/thread.inline.hpp"
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#include "utilities/globalCounter.hpp"
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inline GlobalCounter::CSContext
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GlobalCounter::critical_section_begin(Thread *thread) {
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assert(thread == Thread::current(), "must be current thread");
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uintx old_cnt = Atomic::load(thread->get_rcu_counter());
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// Retain the old counter value if already active, e.g. nested.
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// Otherwise, set the counter to the current version + active bit.
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uintx new_cnt = old_cnt;
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if ((new_cnt & COUNTER_ACTIVE) == 0) {
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new_cnt = Atomic::load(&_global_counter._counter) | COUNTER_ACTIVE;
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}
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Atomic::release_store_fence(thread->get_rcu_counter(), new_cnt);
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return static_cast<CSContext>(old_cnt);
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}
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inline void
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GlobalCounter::critical_section_end(Thread *thread, CSContext context) {
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assert(thread == Thread::current(), "must be current thread");
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assert((*thread->get_rcu_counter() & COUNTER_ACTIVE) == COUNTER_ACTIVE, "must be in critical section");
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// Restore the counter value from before the associated begin.
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Atomic::release_store(thread->get_rcu_counter(),
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static_cast<uintx>(context));
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}
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class GlobalCounter::CriticalSection {
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private:
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Thread* _thread;
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CSContext _context;
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public:
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inline CriticalSection(Thread* thread) :
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_thread(thread),
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_context(GlobalCounter::critical_section_begin(_thread))
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{}
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inline ~CriticalSection() {
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GlobalCounter::critical_section_end(_thread, _context);
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}
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};
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#endif // SHARE_UTILITIES_GLOBALCOUNTER_INLINE_HPP
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