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path: root/src/libcamera/thread.cpp
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2020-03-23libcamera: thread: Order headers alphabeticallyLaurent Pinchart
No code change. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2020-02-14libcamera: thread: Support timeout in wait() functionLaurent Pinchart
Add a parameter to the Thread::wait() function to wait with a timeout. The delay value utils::duration::max() waits forever. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2020-02-13libcamera: Document thread-safety attributes of core classesLaurent Pinchart
Define the thread-safety attributes of the classes and methods that are either thread-safe or thread-bound. The CameraManager, Camera and PipelineHandler will be addressed separately. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2020-02-13libcamera: Define the threading modelLaurent Pinchart
Document the design of libcamera's threading support, and prepare to document thread-safety of classes and functions with a doxygen alias command. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2020-01-20libcamera: thread: Add a method to return the ID of the current threadLaurent Pinchart
The current thread ID is useful when logging message to debug concurrency issues. Add a method to retrieve it. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org>
2019-11-27libcamera: thread: Fix race condition when dispatching messagesLaurent Pinchart
The Object class stores the number of pending messages that have been posted for it, while the actual messages are stored in a per-thread list in the ThreadData class. When dispatching messages, the message is removed from the list, passed to the receiver, and the number of pending messages is updated. In order to avoid too much contention on the list lock, the lock is dropped to pass the message to the receiver and then taken again. This creates a race condition window with Thread::removeMessages(), as the number of pending messages for a receiver is briefly out of sync with the pending messages list. The assertion at the end of removeMessages() thus sometimes fails. Fix this by decrementing the pending messages counter before releasing the lock in Thread::dispatchMessages(). This fixes the slow message receiver test in MessageTest. Fixes: 01b930964acd ("libcamera: thread: Add a messaging passing API") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-11-27libcamera: thread: Fix locking when moving objectLaurent Pinchart
When moving an Object to a Thread, messages posted for the object are move to the target thread's message queue. This requires locking the message queues of the current and target threads, as the target thread may (and is usually) running. The implementation is faulty as it locks the thread data instead of the message queue. This creates a race condition with a tiny but exploitable time window. The issue was noticed by the event-thread test rarely but reproducibly failing with the following assertion error: [1:39:33.850878042]FATAL default thread.cpp:440 assertion "data_ == receiver->thread()->data_" failed The issue only occurred when libcamera was compiled in release mode, further hinting of a race condition. Fixes: 01b930964acd ("libcamera: thread: Add a messaging passing API") Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-11-08libcamera: Remove unneeded semicolonsLaurent Pinchart
Comply with the coding style by removing lots of unneeded semicolons. Fix a few other coding style violations on the lines touched by those fixes. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
2019-08-17libcamera: object: Create parent-child relationshipsLaurent Pinchart
Add a parent Object to Object instances, and track the parent-children relationships. Children are bound to the same thread as their parent, and moving an Object to a thread automatically moves all its children. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-08-17libcamera: thread: Support dispatching messages to main threadLaurent Pinchart
Threads contain message queues and dispatch queued messages in their event loop, in Thread::exec(). This mechanism prevents the main thread from dispatching messages as it doesn't run Thread::exec(). Fix this by moving message dispatching from Thread::exec() to EventDispatcher::processEvents(). Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-08-17libcamera: thread: Wake up target thread when moving objectsLaurent Pinchart
When moving an object to a different thread, messages posted for the object are moved to the message queue of the new thread. Wake up the new thread to ensure it processes the moved messages. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Jacopo Mondi <jacopo@jmondi.org> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-07-11libcamera: thread: Add a messaging passing APILaurent Pinchart
Create a new Message class to model a message that can be passed to an object living in another thread. Only an invalid message type is currently defined, more messages will be added in the future. The Thread class is extended with a messages queue, and the Object class with thread affinity. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
2019-07-11libcamera: Add thread supportLaurent Pinchart
The new Thread class wraps std::thread in order to integrate it with the Object, Signal and EventDispatcher classes. By default new threads run an internal event loop, and their run() method can be overloaded to provide a custom thread loop. Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Reviewed-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>