iox-eclipse-iceoryx#2301 Add SpinLock

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

@@ -726,7 +726,7 @@
     // after
     iox::optional<iox::mutex> myMutex;
     iox::MutexBuilder()
-        .mutexType(iox::MutexType::RECURSIVE)
+        .lock_behavior(iox::LockBehavior::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 +1,93 @@
+// 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
+{
+class SpinLockBuilder;
+
+/// @brief A spin lock implementation as drop-in replacement for a mutex
+class SpinLock : public LockInterface<SpinLock>
+{
+  public:
+    using Builder = SpinLockBuilder;
+
+    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 LockBehavior lock_behavior) 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};
+};
+
+class SpinLockBuilder
+{
+  public:
+    enum class Error : uint8_t
+    {
+        LOCK_ALREADY_INITIALIZED,
+        INTER_PROCESS_LOCK_UNSUPPORTED_BY_PLATFORM,
+        UNKNOWN_ERROR
+    };
+
+    /// @brief Defines if the SpinLock should be usable in an inter process context. Default: true
+    IOX_BUILDER_PARAMETER(bool, is_inter_process_capable, true)
+
+    /// @brief Sets the LockBehavior, default: LockBehavior::RECURSIVE
+    IOX_BUILDER_PARAMETER(LockBehavior, lock_behavior, LockBehavior::RECURSIVE)
+
+  public:
+    /// @brief Initializes a provided uninitialized SpinLock
+    /// @param[in] uninitializedLock the uninitialized SpinLock which should be initialized
+    /// @return On failure LockCreationError which explains the error
+    expected<void, Error> create(optional<SpinLock>& uninitializedLock) noexcept;
+};
+
+} // namespace concurrent
+} // namespace iox
+
+#endif // IOX_HOOFS_CONCURRENT_SYNC_SPIN_LOCK_HPP

iceoryx_hoofs/concurrent/sync/source/spin_lock.cpp

@@ -0,0 +1,128 @@
+// 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
+{
+expected<void, SpinLockBuilder::Error>
+SpinLockBuilder::create(optional<concurrent::SpinLock>& uninitializedLock) noexcept
+{
+    if (uninitializedLock.has_value())
+    {
+        IOX_LOG(ERROR, "Unable to override an already initialized SpinLock with a new SpinLock");
+        return err(Error::LOCK_ALREADY_INITIALIZED);
+    }
+
+    uninitializedLock.emplace(m_lock_behavior);
+    return ok();
+}
+
+SpinLock::SpinLock(const LockBehavior lock_behavior) noexcept
+    : m_recursive(lock_behavior == LockBehavior::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
+} // namespace iox

iceoryx_hoofs/design/include/iox/lock_interface.hpp

@@ -0,0 +1,112 @@
+// 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_DESIGN_LOCK_INTERFACE_HPP
+#define IOX_HOOFS_DESIGN_LOCK_INTERFACE_HPP
+
+#include "iceoryx_platform/pthread.hpp"
+#include "iox/builder.hpp"
+#include "iox/expected.hpp"
+#include "iox/optional.hpp"
+
+#include <cstdint>
+
+namespace iox
+{
+enum class LockError : uint8_t
+{
+    PRIORITY_MISMATCH,
+    MAXIMUM_NUMBER_OF_RECURSIVE_LOCKS_EXCEEDED,
+    DEADLOCK_CONDITION,
+    LOCK_ACQUIRED_BUT_HAS_INCONSISTENT_STATE_SINCE_OWNER_DIED,
+    UNKNOWN_ERROR
+};
+
+enum class UnlockError : uint8_t
+{
+    NOT_OWNED_BY_THREAD,
+    NOT_LOCKED,
+    UNKNOWN_ERROR
+};
+
+enum class TryLockError : uint8_t
+{
+    PRIORITY_MISMATCH,
+    MAXIMUM_NUMBER_OF_RECURSIVE_LOCKS_EXCEEDED,
+    LOCK_ACQUIRED_BUT_HAS_INCONSISTENT_STATE_SINCE_OWNER_DIED,
+    UNKNOWN_ERROR
+};
+
+enum class TryLock : uint8_t
+{
+    LOCK_SUCCEEDED,
+    FAILED_TO_ACQUIRE_LOCK
+};
+
+template <typename Lock>
+class LockInterface
+{
+  public:
+    /// @brief Engages the lock.
+    /// @return When it fails it returns an enum describing the error.
+    expected<void, LockError> lock() noexcept
+    {
+        return static_cast<Lock*>(this)->lock_impl();
+    }
+
+    /// @brief  Releases the lock.
+    /// @return When it fails it returns an enum describing the error.
+    expected<void, UnlockError> unlock() noexcept
+    {
+        return static_cast<Lock*>(this)->unlock_impl();
+    }
+
+    /// @brief Tries to engage the lock.
+    /// @return If the lock was acquired LockInterfaceTryLock::LOCK_SUCCEEDED will be returned otherwise
+    ///         LockInterfaceTryLock::FAILED_TO_ACQUIRE_LOCK.
+    ///         If the lock is a recursive lock, this call will also succeed.
+    ///         On failure it returns an enum describing the failure.
+    expected<TryLock, TryLockError> try_lock() noexcept
+    {
+        return static_cast<Lock*>(this)->try_lock_impl();
+    }
+
+  protected:
+    LockInterface() noexcept = default;
+};
+
+/// @brief Describes the behavior of the lock.
+// NOLINTNEXTLINE(performance-enum-size) int32_t required for POSIX API
+enum class LockBehavior : int32_t
+{
+    /// @brief Behavior without error detection and multiple locks from within
+    ///        the same thread lead to deadlock
+    NORMAL = IOX_PTHREAD_MUTEX_NORMAL,
+
+    /// @brief Multiple locks from within the same thread do not lead to deadlock
+    ///        but one requires the same amount of unlocks to make the thread lockable
+    ///        from other threads
+    RECURSIVE = IOX_PTHREAD_MUTEX_RECURSIVE,
+
+    /// @brief Multiple locks from within the same thread will be detected and
+    ///        reported. It detects also when unlock is called from a different
+    ///        thread.
+    WITH_DEADLOCK_DETECTION = IOX_PTHREAD_MUTEX_ERRORCHECK,
+};
+
+} // namespace iox
+
+#endif // IOX_HOOFS_DESIGN_LOCK_INTERFACE_HPP