IMediaSource: Improve shared memory buffer transfer
Bug: 29125703
Change-Id: Icf1180dee65f6504e6c10dd4d5b28a8e441f67d1
diff --git a/media/libmedia/IMediaSource.cpp b/media/libmedia/IMediaSource.cpp
index d2b4291..2adce19 100644
--- a/media/libmedia/IMediaSource.cpp
+++ b/media/libmedia/IMediaSource.cpp
@@ -36,7 +36,7 @@
STOP,
PAUSE,
GETFORMAT,
- READ,
+ // READ, deprecated
READMULTIPLE,
RELEASE_BUFFER
};
@@ -44,71 +44,30 @@
enum {
NULL_BUFFER,
SHARED_BUFFER,
- INLINE_BUFFER
+ INLINE_BUFFER,
+ SHARED_BUFFER_INDEX,
};
-class RemoteMediaBufferReleaser : public BBinder {
-public:
- RemoteMediaBufferReleaser(MediaBuffer *buf, sp<BnMediaSource> owner) {
- mBuf = buf;
- mOwner = owner;
- }
- ~RemoteMediaBufferReleaser() {
- if (mBuf) {
- ALOGW("RemoteMediaBufferReleaser dtor called while still holding buffer");
- mBuf->release();
- }
- }
- virtual status_t onTransact( uint32_t code,
- const Parcel& data,
- Parcel* reply,
- uint32_t flags = 0) {
- if (code == RELEASE_BUFFER) {
- mBuf->release();
- mBuf = NULL;
- return OK;
- } else {
- return BBinder::onTransact(code, data, reply, flags);
- }
- }
-private:
- MediaBuffer *mBuf;
- // Keep a ref to ensure MediaBuffer is released before the owner, i.e., BnMediaSource,
- // because BnMediaSource needs to delete MediaBufferGroup in its dtor and
- // MediaBufferGroup dtor requires all MediaBuffer's have 0 ref count.
- sp<BnMediaSource> mOwner;
-};
-
-
class RemoteMediaBufferWrapper : public MediaBuffer {
public:
- RemoteMediaBufferWrapper(sp<IMemory> mem, sp<IBinder> source);
+ RemoteMediaBufferWrapper(const sp<IMemory> &mem)
+ : MediaBuffer(mem) {
+ ALOGV("RemoteMediaBufferWrapper: creating %p", this);
+ }
+
protected:
- virtual ~RemoteMediaBufferWrapper();
-private:
- sp<IMemory> mMemory;
- sp<IBinder> mRemoteSource;
+ virtual ~RemoteMediaBufferWrapper() {
+ // Indicate to MediaBufferGroup to release.
+ int32_t old = addPendingRelease(1);
+ ALOGV("RemoteMediaBufferWrapper: releasing %p, old %d", this, old);
+ mMemory.clear(); // don't set the dead object flag.
+ }
};
-RemoteMediaBufferWrapper::RemoteMediaBufferWrapper(sp<IMemory> mem, sp<IBinder> source)
-: MediaBuffer(mem->pointer(), mem->size()) {
- mMemory = mem;
- mRemoteSource = source;
-}
-
-RemoteMediaBufferWrapper::~RemoteMediaBufferWrapper() {
- mMemory.clear();
- // Explicitly ask the remote side to release the buffer. We could also just clear
- // mRemoteSource, but that doesn't immediately release the reference on the remote side.
- Parcel data, reply;
- mRemoteSource->transact(RELEASE_BUFFER, data, &reply);
- mRemoteSource.clear();
-}
-
class BpMediaSource : public BpInterface<IMediaSource> {
public:
BpMediaSource(const sp<IBinder>& impl)
- : BpInterface<IMediaSource>(impl)
+ : BpInterface<IMediaSource>(impl), mBuffersSinceStop(0)
{
}
@@ -135,7 +94,10 @@
ALOGV("stop");
Parcel data, reply;
data.writeInterfaceToken(BpMediaSource::getInterfaceDescriptor());
- return remote()->transact(STOP, data, &reply);
+ status_t status = remote()->transact(STOP, data, &reply);
+ mMemoryCache.reset();
+ mBuffersSinceStop = 0;
+ return status;
}
virtual sp<MetaData> getFormat() {
@@ -151,46 +113,16 @@
}
virtual status_t read(MediaBuffer **buffer, const ReadOptions *options) {
- ALOGV("read");
- Parcel data, reply;
- data.writeInterfaceToken(BpMediaSource::getInterfaceDescriptor());
- if (options) {
- data.writeByteArray(sizeof(*options), (uint8_t*) options);
- }
- status_t ret = remote()->transact(READ, data, &reply);
- if (ret != NO_ERROR) {
- return ret;
- }
- // wrap the returned data in a MediaBuffer
- ret = reply.readInt32();
- int32_t buftype = reply.readInt32();
- if (buftype == SHARED_BUFFER) {
- sp<IBinder> remote = reply.readStrongBinder();
- sp<IBinder> binder = reply.readStrongBinder();
- sp<IMemory> mem = interface_cast<IMemory>(binder);
- if (mem == NULL) {
- ALOGE("received NULL IMemory for shared buffer");
- }
- size_t offset = reply.readInt32();
- size_t length = reply.readInt32();
- MediaBuffer *buf = new RemoteMediaBufferWrapper(mem, remote);
- buf->set_range(offset, length);
- buf->meta_data()->updateFromParcel(reply);
- *buffer = buf;
- } else if (buftype == NULL_BUFFER) {
- ALOGV("got status %d and NULL buffer", ret);
- *buffer = NULL;
- } else {
- int32_t len = reply.readInt32();
- ALOGV("got status %d and len %d", ret, len);
- *buffer = new MediaBuffer(len);
- reply.read((*buffer)->data(), len);
- (*buffer)->meta_data()->updateFromParcel(reply);
- }
+ Vector<MediaBuffer *> buffers;
+ status_t ret = readMultiple(&buffers, 1 /* maxNumBuffers */, options);
+ *buffer = buffers.size() == 0 ? nullptr : buffers[0];
+ ALOGV("read status %d, bufferCount %u, sinceStop %u",
+ ret, *buffer != nullptr, mBuffersSinceStop);
return ret;
}
- virtual status_t readMultiple(Vector<MediaBuffer *> *buffers, uint32_t maxNumBuffers) {
+ virtual status_t readMultiple(
+ Vector<MediaBuffer *> *buffers, uint32_t maxNumBuffers, const ReadOptions *options) {
ALOGV("readMultiple");
if (buffers == NULL || !buffers->isEmpty()) {
return BAD_VALUE;
@@ -198,26 +130,59 @@
Parcel data, reply;
data.writeInterfaceToken(BpMediaSource::getInterfaceDescriptor());
data.writeUint32(maxNumBuffers);
+ if (options != nullptr) {
+ data.writeByteArray(sizeof(*options), (uint8_t*) options);
+ }
status_t ret = remote()->transact(READMULTIPLE, data, &reply);
+ mMemoryCache.gc();
if (ret != NO_ERROR) {
return ret;
}
// wrap the returned data in a vector of MediaBuffers
- int32_t bufCount = 0;
- while (1) {
- if (reply.readInt32() == 0) {
- break;
+ int32_t buftype;
+ uint32_t bufferCount = 0;
+ while ((buftype = reply.readInt32()) != NULL_BUFFER) {
+ LOG_ALWAYS_FATAL_IF(bufferCount >= maxNumBuffers,
+ "Received %u+ buffers and requested %u buffers",
+ bufferCount + 1, maxNumBuffers);
+ MediaBuffer *buf;
+ if (buftype == SHARED_BUFFER || buftype == SHARED_BUFFER_INDEX) {
+ uint64_t index = reply.readUint64();
+ ALOGV("Received %s index %llu",
+ buftype == SHARED_BUFFER ? "SHARED_BUFFER" : "SHARED_BUFFER_INDEX",
+ (unsigned long long) index);
+ sp<IMemory> mem;
+ if (buftype == SHARED_BUFFER) {
+ sp<IBinder> binder = reply.readStrongBinder();
+ mem = interface_cast<IMemory>(binder);
+ LOG_ALWAYS_FATAL_IF(mem.get() == nullptr,
+ "Received NULL IMemory for shared buffer");
+ mMemoryCache.insert(index, mem);
+ } else {
+ mem = mMemoryCache.lookup(index);
+ LOG_ALWAYS_FATAL_IF(mem.get() == nullptr,
+ "Received invalid IMemory index for shared buffer: %llu",
+ (unsigned long long)index);
+ }
+ size_t offset = reply.readInt32();
+ size_t length = reply.readInt32();
+ buf = new RemoteMediaBufferWrapper(mem);
+ buf->set_range(offset, length);
+ buf->meta_data()->updateFromParcel(reply);
+ } else { // INLINE_BUFFER
+ int32_t len = reply.readInt32();
+ ALOGV("INLINE_BUFFER status %d and len %d", ret, len);
+ buf = new MediaBuffer(len);
+ reply.read(buf->data(), len);
+ buf->meta_data()->updateFromParcel(reply);
}
- int32_t len = reply.readInt32();
- ALOGV("got len %d", len);
- MediaBuffer *buf = new MediaBuffer(len);
- reply.read(buf->data(), len);
- buf->meta_data()->updateFromParcel(reply);
buffers->push_back(buf);
- ++bufCount;
+ ++bufferCount;
+ ++mBuffersSinceStop;
}
ret = reply.readInt32();
- ALOGV("got status %d, bufCount %d", ret, bufCount);
+ ALOGV("readMultiple status %d, bufferCount %u, sinceStop %u",
+ ret, bufferCount, mBuffersSinceStop);
return ret;
}
@@ -238,10 +203,51 @@
}
private:
+
+ uint32_t mBuffersSinceStop; // Buffer tracking variable
+
// NuPlayer passes pointers-to-metadata around, so we use this to keep the metadata alive
// XXX: could we use this for caching, or does metadata change on the fly?
sp<MetaData> mMetaData;
+ // Cache all IMemory objects received from MediaExtractor.
+ // We gc IMemory objects that are no longer active (referenced by a MediaBuffer).
+
+ struct MemoryCache {
+ sp<IMemory> lookup(uint64_t index) {
+ auto p = mIndexToMemory.find(index);
+ if (p == mIndexToMemory.end()) {
+ ALOGE("cannot find index!");
+ return nullptr;
+ }
+ return p->second;
+ }
+
+ void insert(uint64_t index, const sp<IMemory> &mem) {
+ if (mIndexToMemory.find(index) != mIndexToMemory.end()) {
+ ALOGE("index %llu already present", (unsigned long long)index);
+ return;
+ }
+ (void)mIndexToMemory.emplace(index, mem);
+ }
+
+ void reset() {
+ mIndexToMemory.clear();
+ }
+
+ void gc() {
+ for (auto it = mIndexToMemory.begin(); it != mIndexToMemory.end(); ) {
+ if (MediaBuffer::isDeadObject(it->second)) {
+ it = mIndexToMemory.erase(it);
+ } else {
+ ++it;
+ }
+ }
+ }
+ private:
+ // C++14 unordered_map erase on iterator is stable; C++11 has no guarantee.
+ std::map<uint64_t, sp<IMemory>> mIndexToMemory;
+ } mMemoryCache;
};
IMPLEMENT_META_INTERFACE(MediaSource, "android.media.IMediaSource");
@@ -250,12 +256,11 @@
#define LOG_TAG "BnMediaSource"
BnMediaSource::BnMediaSource()
- : mGroup(NULL) {
+ : mBuffersSinceStop(0)
+ , mGroup(new MediaBufferGroup(kBinderMediaBuffers /* growthLimit */)) {
}
BnMediaSource::~BnMediaSource() {
- delete mGroup;
- mGroup = NULL;
}
status_t BnMediaSource::onTransact(
@@ -278,7 +283,11 @@
case STOP: {
ALOGV("stop");
CHECK_INTERFACE(IMediaSource, data, reply);
- return stop();
+ status_t status = stop();
+ mGroup->gc();
+ mIndexCache.reset();
+ mBuffersSinceStop = 0;
+ return status;
}
case PAUSE: {
ALOGV("pause");
@@ -295,116 +304,112 @@
}
return UNKNOWN_ERROR;
}
- case READ: {
- ALOGV("read");
- CHECK_INTERFACE(IMediaSource, data, reply);
- status_t ret;
- MediaBuffer *buf = NULL;
- ReadOptions opts;
- uint32_t len;
- if (data.readUint32(&len) == NO_ERROR &&
- len == sizeof(opts) && data.read((void*)&opts, len) == NO_ERROR) {
- ret = read(&buf, &opts);
- } else {
- ret = read(&buf, NULL);
- }
-
- reply->writeInt32(ret);
- if (buf != NULL) {
- size_t usedSize = buf->range_length();
- // even if we're using shared memory, we might not want to use it, since for small
- // sizes it's faster to copy data through the Binder transaction
- // On the other hand, if the data size is large enough, it's better to use shared
- // memory. When data is too large, binder can't handle it.
- if (usedSize >= MediaBuffer::kSharedMemThreshold) {
- ALOGV("use shared memory: %zu", usedSize);
-
- MediaBuffer *transferBuf = buf;
- size_t offset = buf->range_offset();
- if (transferBuf->mMemory == NULL) {
- if (mGroup == NULL) {
- mGroup = new MediaBufferGroup;
- size_t allocateSize = usedSize;
- if (usedSize < SIZE_MAX / 3) {
- allocateSize = usedSize * 3 / 2;
- }
- mGroup->add_buffer(new MediaBuffer(allocateSize));
- }
-
- MediaBuffer *newBuf = NULL;
- ret = mGroup->acquire_buffer(
- &newBuf, false /* nonBlocking */, usedSize);
- if (ret != OK || newBuf == NULL || newBuf->mMemory == NULL) {
- ALOGW("failed to acquire shared memory, ret %d", ret);
- buf->release();
- if (newBuf != NULL) {
- newBuf->release();
- }
- reply->writeInt32(NULL_BUFFER);
- return NO_ERROR;
- }
- transferBuf = newBuf;
- memcpy(transferBuf->data(), (uint8_t*)buf->data() + buf->range_offset(),
- buf->range_length());
- offset = 0;
- }
-
- reply->writeInt32(SHARED_BUFFER);
- RemoteMediaBufferReleaser *wrapper =
- new RemoteMediaBufferReleaser(transferBuf, this);
- reply->writeStrongBinder(wrapper);
- reply->writeStrongBinder(IInterface::asBinder(transferBuf->mMemory));
- reply->writeInt32(offset);
- reply->writeInt32(usedSize);
- buf->meta_data()->writeToParcel(*reply);
- if (buf->mMemory == NULL) {
- buf->release();
- }
- } else {
- // buffer is small: copy it
- if (buf->mMemory != NULL) {
- ALOGV("%zu shared mem available, but only %zu used", buf->mMemory->size(), buf->range_length());
- }
- reply->writeInt32(INLINE_BUFFER);
- reply->writeByteArray(buf->range_length(), (uint8_t*)buf->data() + buf->range_offset());
- buf->meta_data()->writeToParcel(*reply);
- buf->release();
- }
- } else {
- ALOGV("ret %d, buf %p", ret, buf);
- reply->writeInt32(NULL_BUFFER);
- }
- return NO_ERROR;
- }
case READMULTIPLE: {
- ALOGV("readmultiple");
+ ALOGV("readMultiple");
CHECK_INTERFACE(IMediaSource, data, reply);
+
+ // Get max number of buffers to read.
uint32_t maxNumBuffers;
data.readUint32(&maxNumBuffers);
- status_t ret = NO_ERROR;
- uint32_t bufferCount = 0;
if (maxNumBuffers > kMaxNumReadMultiple) {
maxNumBuffers = kMaxNumReadMultiple;
}
- while (bufferCount < maxNumBuffers) {
- if (reply->dataSize() >= MediaBuffer::kSharedMemThreshold) {
+
+ // Get read options, if any.
+ ReadOptions opts;
+ uint32_t len;
+ const bool useOptions =
+ data.readUint32(&len) == NO_ERROR
+ && len == sizeof(opts)
+ && data.read((void *)&opts, len) == NO_ERROR;
+
+ mGroup->gc(kBinderMediaBuffers /* freeBuffers */);
+ mIndexCache.gc();
+ status_t ret = NO_ERROR;
+ uint32_t bufferCount = 0;
+ for (; bufferCount < maxNumBuffers; ++bufferCount, ++mBuffersSinceStop) {
+ MediaBuffer *buf = nullptr;
+ ret = read(&buf, useOptions ? &opts : nullptr);
+ opts.clearNonPersistent(); // Remove options that only apply to first buffer.
+ if (ret != NO_ERROR || buf == nullptr) {
break;
}
- MediaBuffer *buf = NULL;
- ret = read(&buf, NULL);
- if (ret != NO_ERROR || buf == NULL) {
- break;
+ // Even if we're using shared memory, we might not want to use it, since for small
+ // sizes it's faster to copy data through the Binder transaction
+ // On the other hand, if the data size is large enough, it's better to use shared
+ // memory. When data is too large, binder can't handle it.
+ //
+ // TODO: reduce MediaBuffer::kSharedMemThreshold
+ MediaBuffer *transferBuf = nullptr;
+ const size_t length = buf->range_length();
+ size_t offset = buf->range_offset();
+ if (length >= MediaBuffer::kSharedMemThreshold) {
+ if (buf->mMemory != nullptr) {
+ ALOGV("Use shared memory: %zu", length);
+ transferBuf = buf;
+ } else {
+ ALOGD("Large buffer %zu without IMemory!", length);
+ ret = mGroup->acquire_buffer(
+ &transferBuf, false /* nonBlocking */, length);
+ if (ret != OK
+ || transferBuf == nullptr
+ || transferBuf->mMemory == nullptr) {
+ ALOGW("Failed to acquire shared memory, size %zu, ret %d",
+ length, ret);
+ if (transferBuf != nullptr) {
+ transferBuf->release();
+ transferBuf = nullptr;
+ }
+ // Current buffer transmit inline; no more additional buffers.
+ maxNumBuffers = 0;
+ } else {
+ memcpy(transferBuf->data(), (uint8_t*)buf->data() + offset, length);
+ offset = 0;
+ }
+ }
}
- ++bufferCount;
- reply->writeInt32(1); // indicate one more MediaBuffer.
- reply->writeByteArray(
- buf->range_length(), (uint8_t*)buf->data() + buf->range_offset());
- buf->meta_data()->writeToParcel(*reply);
- buf->release();
+ if (transferBuf != nullptr) { // Using shared buffers.
+ if (!transferBuf->isObserved()) {
+ // Transfer buffer must be part of a MediaBufferGroup.
+ ALOGV("adding shared memory buffer %p to local group", transferBuf);
+ mGroup->add_buffer(transferBuf);
+ transferBuf->add_ref(); // We have already acquired buffer.
+ }
+ uint64_t index = mIndexCache.lookup(transferBuf->mMemory);
+ if (index == 0) {
+ index = mIndexCache.insert(transferBuf->mMemory);
+ reply->writeInt32(SHARED_BUFFER);
+ reply->writeUint64(index);
+ reply->writeStrongBinder(IInterface::asBinder(transferBuf->mMemory));
+ ALOGV("SHARED_BUFFER(%p) %llu",
+ transferBuf, (unsigned long long)index);
+ } else {
+ reply->writeInt32(SHARED_BUFFER_INDEX);
+ reply->writeUint64(index);
+ ALOGV("SHARED_BUFFER_INDEX(%p) %llu",
+ transferBuf, (unsigned long long)index);
+ }
+ reply->writeInt32(offset);
+ reply->writeInt32(length);
+ buf->meta_data()->writeToParcel(*reply);
+ if (transferBuf != buf) {
+ buf->release();
+ }
+ } else {
+ ALOGV_IF(buf->mMemory != nullptr,
+ "INLINE(%p) %zu shared mem available, but only %zu used",
+ buf, buf->mMemory->size(), length);
+ reply->writeInt32(INLINE_BUFFER);
+ reply->writeByteArray(length, (uint8_t*)buf->data() + offset);
+ buf->meta_data()->writeToParcel(*reply);
+ buf->release();
+ }
}
- reply->writeInt32(0); // indicate no more MediaBuffer.
+ reply->writeInt32(NULL_BUFFER); // Indicate no more MediaBuffers.
reply->writeInt32(ret);
+ ALOGV("readMultiple status %d, bufferCount %u, sinceStop %u",
+ ret, bufferCount, mBuffersSinceStop);
return NO_ERROR;
}
default: