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Commit 4c3d1ee7 authored by Andy Hung's avatar Andy Hung
Browse files

MediaBuffer: Only use shared memory for processes that export MediaBuffers 

Reduces excess file descriptors and shared memory creation and releases.

Bug: 28930897
Bug: 30341084
Change-Id: I8190e22dd800f25be79ec33cb02613d15482e1d4
parent 3a7867c0

include/media/stagefright/MediaBuffer.h

+10 −0
Original line number Diff line number Diff line
@@ -108,6 +108,14 @@ public: 
        return reinterpret_cast<SharedControl *>(memory->pointer())->isDeadObject();

    }



    // Sticky on enabling of shared memory MediaBuffers. By default we don't use

    // shared memory for MediaBuffers, but we enable this for those processes

    // that export MediaBuffers.

    static void useSharedMemory() {

        std::atomic_store_explicit(

                &mUseSharedMemory, (int_least32_t)1, std::memory_order_seq_cst);

    }



protected:

    // MediaBuffer remote releases are handled through a

    // pending release count variable stored in a SharedControl block
@@ -161,6 +169,8 @@ private: 


    MediaBuffer *mOriginal;



    static std::atomic_int_least32_t mUseSharedMemory;



    MediaBuffer(const MediaBuffer &);

    MediaBuffer &operator=(const MediaBuffer &);

media/libmedia/IMediaExtractorService.cpp

+3 −0
Original line number Diff line number Diff line
@@ -71,6 +71,9 @@ status_t BnMediaExtractorService::onTransact( 
                ALOGE("Error reading source from parcel");

                return ret;

            }

            // If we make an extractor through Binder, enabled shared memory

            // for MediaBuffers for this process.

            MediaBuffer::useSharedMemory();

            sp<IDataSource> source = interface_cast<IDataSource>(b);

            const char *mime = data.readCString();

            sp<IMediaExtractor> ex = makeExtractor(source, mime);

media/libstagefright/foundation/MediaBuffer.cpp

+5 −1
Original line number Diff line number Diff line
@@ -30,6 +30,9 @@ 


namespace android {



/* static */

std::atomic_int_least32_t MediaBuffer::mUseSharedMemory(0);



MediaBuffer::MediaBuffer(void *data, size_t size)

    : mObserver(NULL),

      mRefCount(0),
@@ -52,7 +55,8 @@ MediaBuffer::MediaBuffer(size_t size) 
      mOwnsData(true),

      mMetaData(new MetaData),

      mOriginal(NULL) {

    if (size < kSharedMemThreshold) {

    if (size < kSharedMemThreshold

            || std::atomic_load_explicit(&mUseSharedMemory, std::memory_order_seq_cst) == 0) {

        mData = malloc(size);

    } else {

        ALOGV("creating memoryDealer");