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Commit 89954d93 authored by Yin-Chia Yeh's avatar Yin-Chia Yeh
Browse files

Camera: Free buffers more aggressively 

This change attempts to free buffers managerd by
BufferManager more aggresively to reduce memory pressure.

Also fix a small buffer accounting issue: check detachBuffer
actually returns a non-null buffer.

Test: keep taking single shot in GCA, CTS
Bug: 38483630
Change-Id: I6c64d1dc2244cec4f1300bbf3992f66f2167eed2
parent 629afae6

services/camera/libcameraservice/device3/Camera3BufferManager.cpp

+128 −57
Original line number Diff line number Diff line
@@ -156,6 +156,86 @@ status_t Camera3BufferManager::unregisterStream(int streamId, int streamSetId) { 
    return OK;

}



void Camera3BufferManager::notifyBufferRemoved(int streamId, int streamSetId) {

    Mutex::Autolock l(mLock);

    StreamSet &streamSet = mStreamSetMap.editValueFor(streamSetId);

    size_t& attachedBufferCount =

            streamSet.attachedBufferCountMap.editValueFor(streamId);

    attachedBufferCount--;

}



status_t Camera3BufferManager::checkAndFreeBufferOnOtherStreamsLocked(

        int streamId, int streamSetId) {

    StreamId firstOtherStreamId = CAMERA3_STREAM_ID_INVALID;

    StreamSet &streamSet = mStreamSetMap.editValueFor(streamSetId);

    if (streamSet.streamInfoMap.size() == 1) {

        ALOGV("StreamSet %d has no other stream available to free", streamSetId);

        return OK;

    }



    bool freeBufferIsAttached = false;

    for (size_t i = 0; i < streamSet.streamInfoMap.size(); i++) {

        firstOtherStreamId = streamSet.streamInfoMap[i].streamId;

        if (firstOtherStreamId != streamId) {



            size_t otherBufferCount  =

                    streamSet.handoutBufferCountMap.valueFor(firstOtherStreamId);

            size_t otherAttachedBufferCount =

                    streamSet.attachedBufferCountMap.valueFor(firstOtherStreamId);

            if (otherAttachedBufferCount > otherBufferCount) {

                freeBufferIsAttached = true;

                break;

            }

        }

        firstOtherStreamId = CAMERA3_STREAM_ID_INVALID;

    }

    if (firstOtherStreamId == CAMERA3_STREAM_ID_INVALID || !freeBufferIsAttached) {

        ALOGV("StreamSet %d has no buffer available to free", streamSetId);

        return OK;

    }





    // This will drop the reference to one free buffer, which will effectively free one

    // buffer (from the free buffer list) for the inactive streams.

    size_t totalAllocatedBufferCount = 0;

    for (size_t i = 0; i < streamSet.attachedBufferCountMap.size(); i++) {

        totalAllocatedBufferCount += streamSet.attachedBufferCountMap[i];

    }

    if (totalAllocatedBufferCount > streamSet.allocatedBufferWaterMark) {

        ALOGV("Stream %d: Freeing buffer: detach", firstOtherStreamId);

        sp<Camera3OutputStream> stream =

                mStreamMap.valueFor(firstOtherStreamId).promote();

        if (stream == nullptr) {

            ALOGE("%s: unable to promote stream %d to detach buffer", __FUNCTION__,

                    firstOtherStreamId);

            return INVALID_OPERATION;

        }



        // Detach and then drop the buffer.

        //

        // Need to unlock because the stream may also be calling

        // into the buffer manager in parallel to signal buffer

        // release, or acquire a new buffer.

        bool bufferFreed = false;

        {

            mLock.unlock();

            sp<GraphicBuffer> buffer;

            stream->detachBuffer(&buffer, /*fenceFd*/ nullptr);

            mLock.lock();

            if (buffer.get() != nullptr) {

                bufferFreed = true;

            }

        }

        if (bufferFreed) {

            size_t& otherAttachedBufferCount =

                    streamSet.attachedBufferCountMap.editValueFor(firstOtherStreamId);

            otherAttachedBufferCount--;

        }

    }



    return OK;

}



status_t Camera3BufferManager::getBufferForStream(int streamId, int streamSetId,

        sp<GraphicBuffer>* gb, int* fenceFd) {

    ATRACE_CALL();
@@ -228,61 +308,15 @@ status_t Camera3BufferManager::getBufferForStream(int streamId, int streamSetId, 
        // in returnBufferForStream() if we want to free buffer more quickly.

        // TODO: probably should find out all the inactive stream IDs, and free the firstly found

        // buffers for them.

        StreamId firstOtherStreamId = CAMERA3_STREAM_ID_INVALID;

        if (streamSet.streamInfoMap.size() > 1) {

            bool freeBufferIsAttached = false;

            for (size_t i = 0; i < streamSet.streamInfoMap.size(); i++) {

                firstOtherStreamId = streamSet.streamInfoMap[i].streamId;

                if (firstOtherStreamId != streamId) {

                    size_t otherBufferCount  =

                            streamSet.handoutBufferCountMap.valueFor(firstOtherStreamId);

                    size_t otherAttachedBufferCount =

                            streamSet.attachedBufferCountMap.valueFor(firstOtherStreamId);

                    if (otherAttachedBufferCount > otherBufferCount) {

                        freeBufferIsAttached = true;

                        break;

                    }

                }

                firstOtherStreamId = CAMERA3_STREAM_ID_INVALID;

            }

            if (firstOtherStreamId == CAMERA3_STREAM_ID_INVALID) {

                return OK;

            }



            // This will drop the reference to one free buffer, which will effectively free one

            // buffer for the inactive streams.

            size_t totalAllocatedBufferCount = 0;

            for (size_t i = 0; i < streamSet.attachedBufferCountMap.size(); i++) {

                totalAllocatedBufferCount += streamSet.attachedBufferCountMap[i];

            }

            if (totalAllocatedBufferCount > streamSet.allocatedBufferWaterMark) {

                ALOGV("%s: free a buffer from stream %d", __FUNCTION__, firstOtherStreamId);

                if (freeBufferIsAttached) {

                    ALOGV("Stream %d: Freeing buffer: detach", firstOtherStreamId);

                    sp<Camera3OutputStream> stream =

                            mStreamMap.valueFor(firstOtherStreamId).promote();

                    if (stream == nullptr) {

                        ALOGE("%s: unable to promote stream %d to detach buffer", __FUNCTION__,

                                firstOtherStreamId);

                        return INVALID_OPERATION;

                    }



                    // Detach and then drop the buffer.

                    //

                    // Need to unlock because the stream may also be calling

                    // into the buffer manager in parallel to signal buffer

                    // release, or acquire a new buffer.

                    {

                        mLock.unlock();

                        sp<GraphicBuffer> buffer;

                        stream->detachBuffer(&buffer, /*fenceFd*/ nullptr);

                        mLock.lock();

                    }

                    size_t& otherAttachedBufferCount =

                            streamSet.attachedBufferCountMap.editValueFor(firstOtherStreamId);

                    otherAttachedBufferCount--;

                }

        res = checkAndFreeBufferOnOtherStreamsLocked(streamId, streamSetId);

        if (res != OK) {

            return res;

        }

        // Since we just allocated one new buffer above, try free one more buffer from other streams

        // to prevent total buffer count from growing

        res = checkAndFreeBufferOnOtherStreamsLocked(streamId, streamSetId);

        if (res != OK) {

            return res;

        }

    } else {

        // TODO: implement this.
@@ -292,11 +326,18 @@ status_t Camera3BufferManager::getBufferForStream(int streamId, int streamSetId, 
    return OK;

}



status_t Camera3BufferManager::onBufferReleased(int streamId, int streamSetId) {

status_t Camera3BufferManager::onBufferReleased(

        int streamId, int streamSetId, bool* shouldFreeBuffer) {

    ATRACE_CALL();

    Mutex::Autolock l(mLock);



    if (shouldFreeBuffer == nullptr) {

        ALOGE("%s: shouldFreeBuffer is null", __FUNCTION__);

        return BAD_VALUE;

    }



    Mutex::Autolock l(mLock);

    ALOGV("Stream %d set %d: Buffer released", streamId, streamSetId);

    *shouldFreeBuffer = false;



    if (!checkIfStreamRegisteredLocked(streamId, streamSetId)){

        ALOGV("%s: signaling buffer release for an already unregistered stream "
@@ -311,6 +352,36 @@ status_t Camera3BufferManager::onBufferReleased(int streamId, int streamSetId) { 
        bufferCount--;

        ALOGV("%s: Stream %d set %d: Buffer count now %zu", __FUNCTION__, streamId, streamSetId,

                bufferCount);



        size_t totalAllocatedBufferCount = 0;

        size_t totalHandOutBufferCount = 0;

        for (size_t i = 0; i < streamSet.attachedBufferCountMap.size(); i++) {

            totalAllocatedBufferCount += streamSet.attachedBufferCountMap[i];

            totalHandOutBufferCount += streamSet.handoutBufferCountMap[i];

        }



        size_t newWaterMark = totalHandOutBufferCount + BUFFER_WATERMARK_DEC_THRESHOLD;

        if (totalAllocatedBufferCount > newWaterMark &&

                    streamSet.allocatedBufferWaterMark > newWaterMark) {

            // BufferManager got more than enough buffers, so decrease watermark

            // to trigger more buffers free operation.

            streamSet.allocatedBufferWaterMark = newWaterMark;

            ALOGV("%s: Stream %d set %d: watermark--; now %zu",

                    __FUNCTION__, streamId, streamSetId, streamSet.allocatedBufferWaterMark);

        }



        size_t attachedBufferCount = streamSet.attachedBufferCountMap.valueFor(streamId);

        if (attachedBufferCount <= bufferCount) {

            ALOGV("%s: stream %d has no buffer available to free.", __FUNCTION__, streamId);

        }



        bool freeBufferIsAttached = (attachedBufferCount > bufferCount);

        if (freeBufferIsAttached &&

                totalAllocatedBufferCount > streamSet.allocatedBufferWaterMark &&

                attachedBufferCount > bufferCount + BUFFER_FREE_THRESHOLD) {

            ALOGV("%s: free a buffer from stream %d", __FUNCTION__, streamId);

            *shouldFreeBuffer = true;

        }

    } else {

        // TODO: implement gralloc V1 support

        return BAD_VALUE;

services/camera/libcameraservice/device3/Camera3BufferManager.h

+28 −2
Original line number Diff line number Diff line
@@ -137,14 +137,17 @@ public: 
     * buffer has been reused. The manager will call detachBuffer on the stream

     * if it needs the released buffer otherwise.

     *

     * When shouldFreeBuffer is set to true, caller must detach and free one buffer from the

     * buffer queue, and then call notifyBufferRemoved to update the manager.

     *

     * Return values:

     *

     *  OK:        Buffer release was processed succesfully

     *  BAD_VALUE: stream ID or streamSetId are invalid, or stream ID and stream set ID

     *             combination doesn't match what was registered, or this stream wasn't registered

     *             to this buffer manager before.

     *             to this buffer manager before, or shouldFreeBuffer is null/

     */

    status_t onBufferReleased(int streamId, int streamSetId);

    status_t onBufferReleased(int streamId, int streamSetId, /*out*/bool* shouldFreeBuffer);



    /**

     * This method notifies the manager that certain buffers has been removed from the
@@ -164,12 +167,30 @@ public: 
     */

    status_t onBuffersRemoved(int streamId, int streamSetId, size_t count);



    /**

     * This method notifiers the manager that a buffer is freed from the buffer queue, usually

     * because onBufferReleased signals the caller to free a buffer via the shouldFreeBuffer flag.

     */

    void notifyBufferRemoved(int streamId, int streamSetId);



    /**

     * Dump the buffer manager statistics.

     */

    void     dump(int fd, const Vector<String16> &args) const;



private:

    // allocatedBufferWaterMark will be decreased when:

    //   numAllocatedBuffersThisSet > numHandoutBuffersThisSet + BUFFER_WATERMARK_DEC_THRESHOLD

    // This allows the watermark go back down after a burst of buffer requests

    static const int BUFFER_WATERMARK_DEC_THRESHOLD = 3;



    // onBufferReleased will set shouldFreeBuffer to true when:

    //   numAllocatedBuffersThisSet > allocatedBufferWaterMark AND

    //   numAllocatedBuffersThisStream > numHandoutBuffersThisStream + BUFFER_FREE_THRESHOLD

    // So after a burst of buffer requests and back to steady state, the buffer queue should have

    // (BUFFER_FREE_THRESHOLD + steady state handout buffer count) buffers.

    static const int BUFFER_FREE_THRESHOLD = 3;



    /**

     * Lock to synchronize the access to the methods of this class.

     */
@@ -279,6 +300,11 @@ private: 
     */

    bool checkIfStreamRegisteredLocked(int streamId, int streamSetId) const;



    /**

     * Check if other streams in the stream set has extra buffer available to be freed, and

     * free one if so.

     */

    status_t checkAndFreeBufferOnOtherStreamsLocked(int streamId, int streamSetId);

};



} // namespace camera3

services/camera/libcameraservice/device3/Camera3OutputStream.cpp

+15 −1
Original line number Diff line number Diff line
@@ -691,13 +691,24 @@ void Camera3OutputStream::BufferReleasedListener::onBufferReleased() { 
    }



    ALOGV("Stream %d: Buffer released", stream->getId());

    bool shouldFreeBuffer = false;

    status_t res = stream->mBufferManager->onBufferReleased(

        stream->getId(), stream->getStreamSetId());

        stream->getId(), stream->getStreamSetId(), &shouldFreeBuffer);

    if (res != OK) {

        ALOGE("%s: signaling buffer release to buffer manager failed: %s (%d).", __FUNCTION__,

                strerror(-res), res);

        stream->mState = STATE_ERROR;

    }



    if (shouldFreeBuffer) {

        sp<GraphicBuffer> buffer;

        // Detach and free a buffer (when buffer goes out of scope)

        stream->detachBufferLocked(&buffer, /*fenceFd*/ nullptr);

        if (buffer.get() != nullptr) {

            stream->mBufferManager->notifyBufferRemoved(

                    stream->getId(), stream->getStreamSetId());

        }

    }

}



void Camera3OutputStream::onBuffersRemovedLocked(
@@ -712,7 +723,10 @@ void Camera3OutputStream::onBuffersRemovedLocked( 


status_t Camera3OutputStream::detachBuffer(sp<GraphicBuffer>* buffer, int* fenceFd) {

    Mutex::Autolock l(mLock);

    return detachBufferLocked(buffer, fenceFd);

}



status_t Camera3OutputStream::detachBufferLocked(sp<GraphicBuffer>* buffer, int* fenceFd) {

    ALOGV("Stream %d: detachBuffer", getId());

    if (buffer == nullptr) {

        return BAD_VALUE;

services/camera/libcameraservice/device3/Camera3OutputStream.h

+4 −0
Original line number Diff line number Diff line
@@ -263,7 +263,11 @@ class Camera3OutputStream : 


    virtual status_t getEndpointUsage(uint32_t *usage) const;



    /**

     * Private methods

     */

    void onBuffersRemovedLocked(const std::vector<sp<GraphicBuffer>>&);

    status_t detachBufferLocked(sp<GraphicBuffer>* buffer, int* fenceFd);



}; // class Camera3OutputStream