iox-eclipse-iceoryx#2301 Introduce SpinLock

doc/website/release-notes/iceoryx-unreleased.md

@@ -725,8 +725,8 @@
 
     // after
     iox::optional<iox::mutex> myMutex;
-    iox::MutexBuilder()
-        .mutexType(iox::MutexType::RECURSIVE)
+    iox::LockBuilder()
+        .lock_type(iox::LockType::RECURSIVE)
         .create(myMutex);
     myMutex->lock();
     ```

iceoryx_hoofs/CMakeLists.txt

@@ -104,6 +104,7 @@ iox_add_library(
         cli/source/option_definition.cpp
         cli/source/option_manager.cpp
         concurrent/buffer/source/mpmc_loffli.cpp
+        concurrent/sync/source/spin_lock.cpp
         filesystem/source/file_reader.cpp
         filesystem/source/filesystem.cpp
         memory/source/bump_allocator.cpp

iceoryx_hoofs/concurrent/sync/include/iox/spin_lock.hpp

@@ -0,0 +1,67 @@
+// Copyright (c) 2024 by ekxide IO GmbH. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+#ifndef IOX_HOOFS_CONCURRENT_SYNC_SPIN_LOCK_HPP
+#define IOX_HOOFS_CONCURRENT_SYNC_SPIN_LOCK_HPP
+
+#include "iox/atomic.hpp"
+#include "iox/lock_interface.hpp"
+
+namespace iox
+{
+namespace concurrent
+{
+
+/// @brief A spin lock implementation as drop-in replacement for a mutex
+class SpinLock : public LockInterface<SpinLock>
+{
+  public:
+    SpinLock(const SpinLock&) = delete;
+    SpinLock(SpinLock&&) = delete;
+    SpinLock& operator=(const SpinLock&) = delete;
+    SpinLock& operator=(SpinLock&&) = delete;
+
+    ~SpinLock() noexcept = default;
+
+  private:
+    friend class optional<SpinLock>;
+    friend class LockInterface<SpinLock>;
+
+    explicit SpinLock(const LockType lock_type) noexcept;
+
+    expected<void, LockError> lock_impl() noexcept;
+
+    expected<void, UnlockError> unlock_impl() noexcept;
+
+    expected<TryLock, TryLockError> try_lock_impl() noexcept;
+
+    struct LockInfo
+    {
+        pid_t tid;
+        uint32_t recursive_count;
+    };
+
+  private:
+    concurrent::AtomicFlag m_lock_flag =
+        ATOMIC_FLAG_INIT; // NOTE: only initialization via assignment is guaranteed to work
+    concurrent::Atomic<LockInfo> m_lock_info{LockInfo{0, 0}};
+    const concurrent::Atomic<bool> m_recursive{false};
+};
+
+} // namespace concurrent
+} // namespace iox
+
+#endif // IOX_HOOFS_CONCURRENT_SYNC_SPIN_LOCK_HPP

iceoryx_hoofs/concurrent/sync/source/spin_lock.cpp

@@ -0,0 +1,138 @@
+// Copyright (c) 2024 by ekxide IO GmbH. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+//
+// SPDX-License-Identifier: Apache-2.0
+
+#include "iox/spin_lock.hpp"
+#include "iox/detail/adaptive_wait.hpp"
+
+namespace iox
+{
+namespace concurrent
+{
+SpinLock::SpinLock(const LockType lock_type) noexcept
+    : m_recursive(lock_type == LockType::RECURSIVE)
+{
+}
+
+expected<void, LockError> SpinLock::lock_impl() noexcept
+{
+    pid_t tid = gettid();
+
+    auto lock_info = m_lock_info.load();
+
+    if (lock_info.tid == tid)
+    {
+        if (m_recursive.load(std::memory_order_relaxed))
+        {
+            lock_info.recursive_count += 1;
+            m_lock_info.store(lock_info);
+
+            return ok();
+        }
+
+        return err(LockError::DEADLOCK_CONDITION);
+    }
+
+    detail::adaptive_wait spinner;
+    spinner.wait_loop([this] { return this->m_lock_flag.test_and_set(std::memory_order_acquire); });
+
+    m_lock_info.store(LockInfo{tid, 1});
+
+    return ok();
+}
+
+expected<void, UnlockError> SpinLock::unlock_impl() noexcept
+{
+    pid_t tid = gettid();
+
+    auto lock_info = m_lock_info.load();
+
+    if (lock_info.tid != tid)
+    {
+        return err(UnlockError::NOT_OWNED_BY_THREAD);
+    }
+
+    if (lock_info.recursive_count == 0)
+    {
+        return err(UnlockError::NOT_LOCKED);
+    }
+
+    lock_info.recursive_count -= 1;
+    if (lock_info.recursive_count == 0)
+    {
+        lock_info.tid = 0;
+        m_lock_info.store(lock_info);
+        m_lock_flag.clear(std::memory_order_release);
+    }
+    else
+    {
+        m_lock_info.store(lock_info);
+    }
+
+    return ok();
+}
+
+expected<TryLock, TryLockError> SpinLock::try_lock_impl() noexcept
+{
+    pid_t tid = gettid();
+
+    auto lock_info = m_lock_info.load();
+
+    if (lock_info.tid == tid)
+    {
+        if (m_recursive.load(std::memory_order_relaxed))
+        {
+            lock_info.recursive_count += 1;
+            m_lock_info.store(lock_info);
+            return ok(TryLock::LOCK_SUCCEEDED);
+        }
+
+        return ok(TryLock::FAILED_TO_ACQUIRE_LOCK);
+    }
+
+    if (!m_lock_flag.test_and_set(std::memory_order_acquire))
+    {
+        m_lock_info.store(LockInfo{tid, 1});
+
+        return ok(TryLock::LOCK_SUCCEEDED);
+    }
+    return ok(TryLock::FAILED_TO_ACQUIRE_LOCK);
+}
+
+
+} // namespace concurrent
+
+template <>
+expected<void, LockCreationError>
+LockBuilder::create<concurrent::SpinLock>(optional<concurrent::SpinLock>& uninitializedLock) noexcept
+{
+    if (m_priority_inheritance != LockPriorityInheritance::NONE)
+    {
+        return err(LockCreationError::USED_PRIORITY_UNSUPPORTED_BY_LOCK);
+    }
+    if (m_priority_ceiling.has_value())
+    {
+        return err(LockCreationError::PRIORITY_CEILING_NOT_SUPPORTED_BY_LOCK);
+    }
+    if (m_thread_termination_behavior != LockThreadTerminationBehavior::STALL_WHEN_LOCKED)
+    {
+        return err(LockCreationError::USED_THREAD_TERMINATION_BEHAVIOR_UNSUPPORTED_BY_LOCK);
+    }
+
+    uninitializedLock.emplace(m_lock_type);
+    return ok();
+}
+
+} // namespace iox