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Commit 1efe099a authored by Jamie Gennis's avatar Jamie Gennis
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BufferQueue: alloc without holding the lock 

This change makes BufferQueue::dequeueBuffer release its mutex before
allocating new buffers.  This should alleviate lock contention in
SurfaceFlinger where SF's main thread can get blocked waiting for an allocation
operation to complete.

Bug: 7335075
Change-Id: I1b000539cc616a695afab2e9c68507db69e57b13
parent f0c89b28

libs/gui/BufferQueue.cpp

+25 −11
Original line number Original line Diff line number Diff line
@@ -385,18 +385,8 @@ status_t BufferQueue::dequeueBuffer(int *outBuf, sp<Fence>& outFence, 
            (uint32_t(buffer->format) != format) ||

            (uint32_t(buffer->format) != format) ||

            ((uint32_t(buffer->usage) & usage) != usage))

            ((uint32_t(buffer->usage) & usage) != usage))

        {

        {

            status_t error;

            sp<GraphicBuffer> graphicBuffer(

                    mGraphicBufferAlloc->createGraphicBuffer(

                            w, h, format, usage, &error));

            if (graphicBuffer == 0) {

                ST_LOGE("dequeueBuffer: SurfaceComposer::createGraphicBuffer "

                        "failed");

                return error;

            }



            mSlots[buf].mAcquireCalled = false;

            mSlots[buf].mAcquireCalled = false;

            mSlots[buf].mGraphicBuffer = graphicBuffer;

            mSlots[buf].mGraphicBuffer = NULL;

            mSlots[buf].mRequestBufferCalled = false;

            mSlots[buf].mRequestBufferCalled = false;

            mSlots[buf].mEglFence = EGL_NO_SYNC_KHR;

            mSlots[buf].mEglFence = EGL_NO_SYNC_KHR;

            mSlots[buf].mFence.clear();

            mSlots[buf].mFence.clear();
@@ -412,6 +402,30 @@ status_t BufferQueue::dequeueBuffer(int *outBuf, sp<Fence>& outFence, 
        mSlots[buf].mFence.clear();

        mSlots[buf].mFence.clear();

    }  // end lock scope

    }  // end lock scope





    if (returnFlags & ISurfaceTexture::BUFFER_NEEDS_REALLOCATION) {

        status_t error;

        sp<GraphicBuffer> graphicBuffer(

                mGraphicBufferAlloc->createGraphicBuffer(

                        w, h, format, usage, &error));

        if (graphicBuffer == 0) {

            ST_LOGE("dequeueBuffer: SurfaceComposer::createGraphicBuffer "

                    "failed");

            return error;

        }



        { // Scope for the lock

            Mutex::Autolock lock(mMutex);



            if (mAbandoned) {

                ST_LOGE("dequeueBuffer: SurfaceTexture has been abandoned!");

                return NO_INIT;

            }



            mSlots[*outBuf].mGraphicBuffer = graphicBuffer;

        }

    }





    if (eglFence != EGL_NO_SYNC_KHR) {

    if (eglFence != EGL_NO_SYNC_KHR) {

        EGLint result = eglClientWaitSyncKHR(dpy, eglFence, 0, 1000000000);

        EGLint result = eglClientWaitSyncKHR(dpy, eglFence, 0, 1000000000);

        // If something goes wrong, log the error, but return the buffer without

        // If something goes wrong, log the error, but return the buffer without