[libcamera-devel] [PATCH v5 3/4] android: post_processor: Make post processing async
Umang Jain
umang.jain at ideasonboard.com
Wed Oct 20 12:42:11 CEST 2021
Introduce a dedicated worker class derived from libcamera::Thread.
The worker class maintains a queue for post-processing requests
and waits for a post-processing request to become available.
It will process them as per FIFO before de-queuing it from the
queue.
To get access to the source and destination buffers in the worker
thread, we also need to save a pointer to them in the
Camera3RequestDescriptor.
This patch also implements a flush() for the PostProcessorWorker
class which is responsible to purge post-processing requests
queued up while a camera is stopping/flushing. It is hooked with
CameraStream::flush(), which isn't used currently but will be
used when we handle flush/stop scnearios in greater detail
subsequently (in a different patchset).
The libcamera request completion handler CameraDevice::requestComplete()
assumes that the request that has just completed is at the front of the
queue. Now that the post-processor runs asynchronously, this isn't true
anymore, a request being post-processed will stay in the queue and a new
libcamera request may complete. Remove that assumption, and use the
request cookie to obtain the Camera3RequestDescriptor.
Signed-off-by: Umang Jain <umang.jain at ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
src/android/camera_device.cpp | 46 +++++----------
src/android/camera_request.h | 4 ++
src/android/camera_stream.cpp | 107 +++++++++++++++++++++++++++++++---
src/android/camera_stream.h | 38 +++++++++++-
4 files changed, 156 insertions(+), 39 deletions(-)
diff --git a/src/android/camera_device.cpp b/src/android/camera_device.cpp
index 541c2c81..b14416ce 100644
--- a/src/android/camera_device.cpp
+++ b/src/android/camera_device.cpp
@@ -1020,29 +1020,8 @@ int CameraDevice::processCaptureRequest(camera3_capture_request_t *camera3Reques
void CameraDevice::requestComplete(Request *request)
{
- Camera3RequestDescriptor *descriptor;
- {
- MutexLocker descriptorsLock(descriptorsMutex_);
- ASSERT(!descriptors_.empty());
- descriptor = descriptors_.front().get();
- }
-
- if (descriptor->request_->cookie() != request->cookie()) {
- /*
- * \todo Clarify if the Camera has to be closed on
- * ERROR_DEVICE.
- */
- LOG(HAL, Error)
- << "Out-of-order completion for request "
- << utils::hex(request->cookie());
-
- MutexLocker descriptorsLock(descriptorsMutex_);
- descriptors_.pop();
-
- notifyError(0, nullptr, CAMERA3_MSG_ERROR_DEVICE);
-
- return;
- }
+ Camera3RequestDescriptor *descriptor =
+ reinterpret_cast<Camera3RequestDescriptor *>(request->cookie());
/*
* Prepare the capture result for the Android camera stack.
@@ -1120,12 +1099,7 @@ void CameraDevice::requestComplete(Request *request)
bool needsPostProcessing = false;
Camera3RequestDescriptor::Status processingStatus =
Camera3RequestDescriptor::Status::Pending;
- /*
- * \todo Apply streamsProcessMutex_ when post-processing is adapted to run
- * asynchronously. If we introduce the streamsProcessMutex_ right away, the
- * lock will be held forever since it is synchronous at this point
- * (see streamProcessingComplete).
- */
+
for (auto &buffer : descriptor->buffers_) {
CameraStream *stream = buffer.stream;
@@ -1145,7 +1119,13 @@ void CameraDevice::requestComplete(Request *request)
buffer.internalBuffer = src;
needsPostProcessing = true;
- int ret = stream->process(*src, buffer, descriptor);
+
+ int ret;
+ {
+ MutexLocker locker(descriptor->streamsProcessMutex_);
+ ret = stream->process(*src, buffer, descriptor);
+ }
+
if (ret) {
setBufferStatus(stream, buffer, descriptor,
Camera3RequestDescriptor::Status::Error);
@@ -1156,6 +1136,12 @@ void CameraDevice::requestComplete(Request *request)
if (needsPostProcessing) {
if (processingStatus == Camera3RequestDescriptor::Status::Error) {
descriptor->status_ = processingStatus;
+ /*
+ * \todo This is problematic when some streams are
+ * queued successfully, but some fail to get queued.
+ * We might end up with use-after-free situation for
+ * descriptor in streamProcessingComplete().
+ */
sendCaptureResults();
}
diff --git a/src/android/camera_request.h b/src/android/camera_request.h
index 3a2774e0..85274414 100644
--- a/src/android/camera_request.h
+++ b/src/android/camera_request.h
@@ -18,6 +18,7 @@
#include <hardware/camera3.h>
+#include "camera_buffer.h"
#include "camera_metadata.h"
#include "camera_worker.h"
@@ -39,6 +40,9 @@ public:
int fence;
Status status;
libcamera::FrameBuffer *internalBuffer = nullptr;
+ std::unique_ptr<CameraBuffer> destBuffer;
+ const libcamera::FrameBuffer *srcBuffer;
+ Camera3RequestDescriptor *request = nullptr;
};
Camera3RequestDescriptor(libcamera::Camera *camera,
diff --git a/src/android/camera_stream.cpp b/src/android/camera_stream.cpp
index b3cb06a2..a29ce33b 100644
--- a/src/android/camera_stream.cpp
+++ b/src/android/camera_stream.cpp
@@ -99,6 +99,7 @@ int CameraStream::configure()
if (ret)
return ret;
+ worker_ = std::make_unique<PostProcessorWorker>(postProcessor_.get());
postProcessor_->processComplete.connect(
this, [&](Camera3RequestDescriptor *request, PostProcessor::Status status) {
Camera3RequestDescriptor::Status bufferStatus =
@@ -110,6 +111,7 @@ int CameraStream::configure()
cameraDevice_->streamProcessingComplete(this, request,
bufferStatus);
});
+ worker_->start();
}
if (type_ == Type::Internal) {
@@ -179,23 +181,31 @@ int CameraStream::process(const FrameBuffer &source,
if (!postProcessor_)
return 0;
- /*
- * \todo Buffer mapping and processing should be moved to a
- * separate thread.
- */
const StreamConfiguration &output = configuration();
- CameraBuffer destBuffer(*dest.camera3Buffer, output.pixelFormat,
- output.size, PROT_READ | PROT_WRITE);
- if (!destBuffer.isValid()) {
+ dest.destBuffer = std::make_unique<CameraBuffer>(
+ *dest.camera3Buffer, output.pixelFormat, output.size, PROT_READ | PROT_WRITE);
+ if (!dest.destBuffer->isValid()) {
LOG(HAL, Error) << "Failed to create destination buffer";
return -EINVAL;
}
- postProcessor_->process(source, &destBuffer, request);
+ dest.srcBuffer = &source;
+ dest.request = request;
+
+ /* Push the postProcessor request to the worker queue. */
+ worker_->queueRequest(&dest);
return 0;
}
+void CameraStream::flush()
+{
+ if (!postProcessor_)
+ return;
+
+ worker_->flush();
+}
+
FrameBuffer *CameraStream::getBuffer()
{
if (!allocator_)
@@ -223,3 +233,84 @@ void CameraStream::putBuffer(FrameBuffer *buffer)
buffers_.push_back(buffer);
}
+
+CameraStream::PostProcessorWorker::PostProcessorWorker(PostProcessor *postProcessor)
+ : postProcessor_(postProcessor)
+{
+}
+
+CameraStream::PostProcessorWorker::~PostProcessorWorker()
+{
+ {
+ libcamera::MutexLocker lock(mutex_);
+ state_ = State::Stopped;
+ }
+
+ cv_.notify_one();
+ wait();
+}
+
+void CameraStream::PostProcessorWorker::start()
+{
+ {
+ libcamera::MutexLocker lock(mutex_);
+ state_ = State::Running;
+ }
+
+ Thread::start();
+}
+
+void CameraStream::PostProcessorWorker::queueRequest(Camera3RequestDescriptor::StreamBuffer *dest)
+{
+ {
+ MutexLocker lock(mutex_);
+ ASSERT(state_ == State::Running);
+ requests_.push(dest);
+ }
+
+ cv_.notify_one();
+}
+
+void CameraStream::PostProcessorWorker::run()
+{
+ MutexLocker locker(mutex_);
+
+ while (1) {
+ cv_.wait(locker, [&] {
+ return state_ != State::Running || !requests_.empty();
+ });
+
+ if (state_ != State::Running)
+ break;
+
+ Camera3RequestDescriptor::StreamBuffer *stream = requests_.front();
+ requests_.pop();
+ locker.unlock();
+
+ postProcessor_->process(*stream->srcBuffer, stream->destBuffer.get(),
+ stream->request);
+
+ locker.lock();
+ }
+
+ if (state_ == State::Flushing) {
+ while (!requests_.empty()) {
+ postProcessor_->processComplete.emit(
+ requests_.front()->request,
+ PostProcessor::Status::Error);
+ requests_.pop();
+ }
+
+ state_ = State::Stopped;
+ locker.unlock();
+ }
+}
+
+void CameraStream::PostProcessorWorker::flush()
+{
+ libcamera::MutexLocker lock(mutex_);
+ state_ = State::Flushing;
+ lock.unlock();
+
+ cv_.notify_one();
+}
diff --git a/src/android/camera_stream.h b/src/android/camera_stream.h
index f242336e..64e32c77 100644
--- a/src/android/camera_stream.h
+++ b/src/android/camera_stream.h
@@ -7,12 +7,16 @@
#ifndef __ANDROID_CAMERA_STREAM_H__
#define __ANDROID_CAMERA_STREAM_H__
+#include <condition_variable>
#include <memory>
#include <mutex>
+#include <queue>
#include <vector>
#include <hardware/camera3.h>
+#include <libcamera/base/thread.h>
+
#include <libcamera/camera.h>
#include <libcamera/framebuffer.h>
#include <libcamera/framebuffer_allocator.h>
@@ -20,9 +24,9 @@
#include <libcamera/pixel_format.h>
#include "camera_request.h"
+#include "post_processor.h"
class CameraDevice;
-class PostProcessor;
class CameraStream
{
@@ -126,8 +130,38 @@ public:
Camera3RequestDescriptor *request);
libcamera::FrameBuffer *getBuffer();
void putBuffer(libcamera::FrameBuffer *buffer);
+ void flush();
private:
+ class PostProcessorWorker : public libcamera::Thread
+ {
+ public:
+ enum class State {
+ Stopped,
+ Running,
+ Flushing,
+ };
+
+ PostProcessorWorker(PostProcessor *postProcessor);
+ ~PostProcessorWorker();
+
+ void start();
+ void queueRequest(Camera3RequestDescriptor::StreamBuffer *request);
+ void flush();
+
+ protected:
+ void run() override;
+
+ private:
+ PostProcessor *postProcessor_;
+
+ libcamera::Mutex mutex_;
+ std::condition_variable cv_;
+
+ std::queue<Camera3RequestDescriptor::StreamBuffer *> requests_;
+ State state_;
+ };
+
int waitFence(int fence);
CameraDevice *const cameraDevice_;
@@ -144,6 +178,8 @@ private:
*/
std::unique_ptr<std::mutex> mutex_;
std::unique_ptr<PostProcessor> postProcessor_;
+
+ std::unique_ptr<PostProcessorWorker> worker_;
};
#endif /* __ANDROID_CAMERA_STREAM__ */
--
2.31.0
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