blast: implicitly cache buffers
Sending buffers between processes is expensive so they must be
cached. Currently buffers are explictly cached. This patch
updates them to implicitly cache them per client process.
The max buffers per process is 64. After that, the cache
will try to evict buffers that have been destroyed. If it doesn't
find any, it will evict the least recently used buffer.
Test: Transaction_test
Bug: 80477568
Change-Id: Id048d32e05e19d0ce875212cbcddf997736110fd
diff --git a/libs/gui/SurfaceComposerClient.cpp b/libs/gui/SurfaceComposerClient.cpp
index c712bde..da624cc 100644
--- a/libs/gui/SurfaceComposerClient.cpp
+++ b/libs/gui/SurfaceComposerClient.cpp
@@ -48,6 +48,9 @@
#include <private/gui/ComposerService.h>
+// This server size should always be smaller than the server cache size
+#define BUFFER_CACHE_MAX_SIZE 64
+
namespace android {
using ui::ColorMode;
@@ -230,6 +233,113 @@
// ---------------------------------------------------------------------------
+class BufferCache : public Singleton<BufferCache> {
+public:
+ BufferCache() : token(new BBinder()) {}
+
+ sp<IBinder> getToken() {
+ return IInterface::asBinder(TransactionCompletedListener::getIInstance());
+ }
+
+ int32_t getId(const sp<GraphicBuffer>& buffer) {
+ std::lock_guard lock(mMutex);
+
+ auto itr = mBuffers.find(buffer);
+ if (itr == mBuffers.end()) {
+ return -1;
+ }
+ itr->second.counter = getCounter();
+ return itr->second.id;
+ }
+
+ int32_t cache(const sp<GraphicBuffer>& buffer) {
+ std::lock_guard lock(mMutex);
+
+ int32_t bufferId = getNextAvailableId();
+
+ mBuffers[buffer].id = bufferId;
+ mBuffers[buffer].counter = getCounter();
+ return bufferId;
+ }
+
+private:
+ int32_t evictDestroyedBuffer() REQUIRES(mMutex) {
+ auto itr = mBuffers.begin();
+ while (itr != mBuffers.end()) {
+ auto& buffer = itr->first;
+ if (buffer == nullptr || buffer.promote() == nullptr) {
+ int32_t bufferId = itr->second.id;
+ mBuffers.erase(itr);
+ return bufferId;
+ }
+ itr++;
+ }
+ return -1;
+ }
+
+ int32_t evictLeastRecentlyUsedBuffer() REQUIRES(mMutex) {
+ if (mBuffers.size() < 0) {
+ return -1;
+ }
+ auto itr = mBuffers.begin();
+ uint64_t minCounter = itr->second.counter;
+ auto minBuffer = itr;
+ itr++;
+
+ while (itr != mBuffers.end()) {
+ uint64_t counter = itr->second.counter;
+ if (counter < minCounter) {
+ minCounter = counter;
+ minBuffer = itr;
+ }
+ itr++;
+ }
+ int32_t minBufferId = minBuffer->second.id;
+ mBuffers.erase(minBuffer);
+ return minBufferId;
+ }
+
+ int32_t getNextAvailableId() REQUIRES(mMutex) {
+ static int32_t id = 0;
+ if (id + 1 < BUFFER_CACHE_MAX_SIZE) {
+ return id++;
+ }
+
+ // There are no more valid cache ids. To set additional buffers, evict existing buffers
+ // and reuse their cache ids.
+ int32_t bufferId = evictDestroyedBuffer();
+ if (bufferId > 0) {
+ return bufferId;
+ }
+ return evictLeastRecentlyUsedBuffer();
+ }
+
+ uint64_t getCounter() REQUIRES(mMutex) {
+ static uint64_t counter = 0;
+ return counter++;
+ }
+
+ struct Metadata {
+ // The cache id of a buffer that can be set to ISurfaceComposer. When ISurfaceComposer
+ // recieves this id, it can retrieve the buffer from its cache. Caching GraphicBuffers
+ // is important because sending them across processes is expensive.
+ int32_t id = 0;
+ // When a buffer is set, a counter is incremented and stored in the cache's metadata.
+ // When an buffer must be evicted, the entry with the lowest counter value is chosen.
+ uint64_t counter = 0;
+ };
+
+ std::mutex mMutex;
+ std::map<wp<GraphicBuffer>, Metadata> mBuffers GUARDED_BY(mMutex);
+
+ // Used by ISurfaceComposer to identify which process is sending the cached buffer.
+ sp<IBinder> token;
+};
+
+ANDROID_SINGLETON_STATIC_INSTANCE(BufferCache);
+
+// ---------------------------------------------------------------------------
+
SurfaceComposerClient::Transaction::Transaction(const Transaction& other)
: mForceSynchronous(other.mForceSynchronous),
mTransactionNestCount(other.mTransactionNestCount),
@@ -772,22 +882,17 @@
mStatus = BAD_INDEX;
return *this;
}
- s->what |= layer_state_t::eBufferChanged;
- s->buffer = buffer;
- registerSurfaceControlForCallback(sc);
- return *this;
-}
+ int32_t bufferId = BufferCache::getInstance().getId(buffer);
+ if (bufferId < 0) {
+ bufferId = BufferCache::getInstance().cache(buffer);
-SurfaceComposerClient::Transaction& SurfaceComposerClient::Transaction::setCachedBuffer(
- const sp<SurfaceControl>& sc, int32_t bufferId) {
- layer_state_t* s = getLayerState(sc);
- if (!s) {
- mStatus = BAD_INDEX;
- return *this;
+ s->what |= layer_state_t::eBufferChanged;
+ s->buffer = buffer;
}
+
s->what |= layer_state_t::eCachedBufferChanged;
- s->cachedBuffer.token = IInterface::asBinder(TransactionCompletedListener::getIInstance());
+ s->cachedBuffer.token = BufferCache::getInstance().getToken();
s->cachedBuffer.bufferId = bufferId;
registerSurfaceControlForCallback(sc);
@@ -1230,26 +1335,6 @@
// ----------------------------------------------------------------------------
-status_t SurfaceComposerClient::cacheBuffer(const sp<GraphicBuffer>& buffer, int32_t* outBufferId) {
- sp<ISurfaceComposer> sf(ComposerService::getComposerService());
- if (buffer == nullptr || outBufferId == nullptr) {
- return BAD_VALUE;
- }
- return sf->cacheBuffer(IInterface::asBinder(TransactionCompletedListener::getIInstance()),
- buffer, outBufferId);
-}
-
-status_t SurfaceComposerClient::uncacheBuffer(int32_t bufferId) {
- sp<ISurfaceComposer> sf(ComposerService::getComposerService());
- if (bufferId < 0) {
- return BAD_VALUE;
- }
- return sf->uncacheBuffer(IInterface::asBinder(TransactionCompletedListener::getIInstance()),
- bufferId);
-}
-
-// ----------------------------------------------------------------------------
-
status_t SurfaceComposerClient::enableVSyncInjections(bool enable) {
sp<ISurfaceComposer> sf(ComposerService::getComposerService());
return sf->enableVSyncInjections(enable);