94 lines
2.4 KiB
C++
94 lines
2.4 KiB
C++
/*
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Copyright (c) 2021-2023 Intel Corporation
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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#ifndef __TBB_mutex_H
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#define __TBB_mutex_H
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#include "detail/_namespace_injection.h"
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#include "detail/_utils.h"
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#include "detail/_scoped_lock.h"
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#include "detail/_waitable_atomic.h"
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#include "detail/_mutex_common.h"
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#include "profiling.h"
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namespace tbb {
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namespace detail {
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namespace d1 {
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class mutex {
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public:
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//! Constructors
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mutex() {
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create_itt_sync(this, "tbb::mutex", "");
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};
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//! Destructor
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~mutex() = default;
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//! No Copy
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mutex(const mutex&) = delete;
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mutex& operator=(const mutex&) = delete;
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using scoped_lock = unique_scoped_lock<mutex>;
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//! Mutex traits
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static constexpr bool is_rw_mutex = false;
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static constexpr bool is_recursive_mutex = false;
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static constexpr bool is_fair_mutex = false;
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//! Acquire lock
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/** Spin if the lock is taken */
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void lock() {
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call_itt_notify(prepare, this);
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while (!try_lock()) {
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my_flag.wait(true, /* context = */ 0, std::memory_order_relaxed);
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}
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}
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//! Try acquiring lock (non-blocking)
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/** Return true if lock acquired; false otherwise. */
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bool try_lock() {
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bool result = !my_flag.load(std::memory_order_relaxed) && !my_flag.exchange(true);
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if (result) {
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call_itt_notify(acquired, this);
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}
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return result;
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}
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//! Release lock
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void unlock() {
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call_itt_notify(releasing, this);
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// We need Write Read memory barrier before notify that reads the waiter list.
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// In C++ only full fence covers this type of barrier.
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my_flag.exchange(false);
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my_flag.notify_one_relaxed();
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}
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private:
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waitable_atomic<bool> my_flag{0};
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}; // class mutex
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} // namespace d1
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} // namespace detail
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inline namespace v1 {
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using detail::d1::mutex;
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} // namespace v1
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} // namespace tbb
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#endif // __TBB_mutex_H
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