Push HWC cache slot generation down into CompositionEngine
Stop caching buffers inside SurfaceFlinger and remove the tight coupling
between SurfaceFlinger's ClientCache and the Hardware Composer cache.
This allows a better seperation of responsibility, where buffer cache
management is not split between HwcSlotGenerator and HwcBufferCache, but
is instead solely handled by HwcBufferCache.
Note that FramebufferSurface and VirtualDisplaySurface no longer use
HwcBufferCache, but instead use their own cache slot management that
is solely based on BufferQueue slot numbers.
Also do minor refactoring in FramebufferSurface to simplify code.
Bug: 258196272
Test: started and stopped multiple YouTube videos on adt4 and verified
no change in graphic buffer usage
Test: atest HwcBufferCacheTest
Test: atest OutputPrepareTest
Change-Id: Ica7955ab4bc70e3c70207390e36dff73a2fc4949
diff --git a/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp b/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp
index f95382d..d64fd57 100644
--- a/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/HwcBufferCache.cpp
@@ -16,43 +16,80 @@
#include <compositionengine/impl/HwcBufferCache.h>
-// TODO(b/129481165): remove the #pragma below and fix conversion issues
-#pragma clang diagnostic push
-#pragma clang diagnostic ignored "-Wconversion"
-
#include <gui/BufferQueue.h>
#include <ui/GraphicBuffer.h>
-// TODO(b/129481165): remove the #pragma below and fix conversion issues
-#pragma clang diagnostic pop // ignored "-Wconversion"
-
namespace android::compositionengine::impl {
HwcBufferCache::HwcBufferCache() {
- std::fill(std::begin(mBuffers), std::end(mBuffers), wp<GraphicBuffer>(nullptr));
+ for (uint32_t i = 0; i < kMaxLayerBufferCount; i++) {
+ mFreeSlots.push(i);
+ }
}
-void HwcBufferCache::getHwcBuffer(int slot, const sp<GraphicBuffer>& buffer, uint32_t* outSlot,
- sp<GraphicBuffer>* outBuffer) {
- // default is 0
- if (slot == BufferQueue::INVALID_BUFFER_SLOT || slot < 0 ||
- slot >= static_cast<int32_t>(kMaxLayerBufferCount)) {
- *outSlot = 0;
- } else {
- *outSlot = static_cast<uint32_t>(slot);
+HwcSlotAndBuffer HwcBufferCache::getHwcSlotAndBuffer(const sp<GraphicBuffer>& buffer) {
+ // TODO(b/261930578): This is for unit tests which don't mock GraphicBuffers but instead send
+ // in nullptrs.
+ if (buffer == nullptr) {
+ return {0, nullptr};
}
-
- auto& currentBuffer = mBuffers[*outSlot];
- wp<GraphicBuffer> weakCopy(buffer);
- if (currentBuffer == weakCopy) {
- // already cached in HWC, skip sending the buffer
- *outBuffer = nullptr;
- } else {
- *outBuffer = buffer;
-
- // update cache
- currentBuffer = buffer;
+ if (auto i = mCacheByBufferId.find(buffer->getId()); i != mCacheByBufferId.end()) {
+ Cache& cache = i->second;
+ // mark this cache slot as more recently used so it won't get evicted anytime soon
+ cache.lruCounter = mLeastRecentlyUsedCounter++;
+ return {cache.slot, nullptr};
}
+ return {cache(buffer), buffer};
+}
+
+HwcSlotAndBuffer HwcBufferCache::getHwcSlotAndBufferForOverride(const sp<GraphicBuffer>& buffer) {
+ if (buffer == mLastOverrideBuffer) {
+ return {kOverrideBufferSlot, nullptr};
+ }
+ mLastOverrideBuffer = buffer;
+ return {kOverrideBufferSlot, buffer};
+}
+
+uint32_t HwcBufferCache::uncache(uint64_t bufferId) {
+ if (auto i = mCacheByBufferId.find(bufferId); i != mCacheByBufferId.end()) {
+ uint32_t slot = i->second.slot;
+ mCacheByBufferId.erase(i);
+ mFreeSlots.push(slot);
+ return slot;
+ }
+ if (mLastOverrideBuffer && bufferId == mLastOverrideBuffer->getId()) {
+ mLastOverrideBuffer = nullptr;
+ return kOverrideBufferSlot;
+ }
+ return UINT32_MAX;
+}
+
+uint32_t HwcBufferCache::cache(const sp<GraphicBuffer>& buffer) {
+ Cache cache;
+ cache.slot = getLeastRecentlyUsedSlot();
+ cache.lruCounter = mLeastRecentlyUsedCounter++;
+ cache.buffer = buffer;
+ mCacheByBufferId.emplace(buffer->getId(), cache);
+ return cache.slot;
+}
+
+uint32_t HwcBufferCache::getLeastRecentlyUsedSlot() {
+ if (mFreeSlots.empty()) {
+ assert(!mCacheByBufferId.empty());
+ // evict the least recently used cache entry
+ auto cacheToErase = mCacheByBufferId.begin();
+ for (auto i = cacheToErase; i != mCacheByBufferId.end(); ++i) {
+ if (i->second.lruCounter < cacheToErase->second.lruCounter) {
+ cacheToErase = i;
+ }
+ }
+ uint32_t slot = cacheToErase->second.slot;
+ mCacheByBufferId.erase(cacheToErase);
+ mFreeSlots.push(slot);
+ }
+ uint32_t slot = mFreeSlots.top();
+ mFreeSlots.pop();
+ return slot;
}
} // namespace android::compositionengine::impl
diff --git a/services/surfaceflinger/CompositionEngine/src/LayerFECompositionState.cpp b/services/surfaceflinger/CompositionEngine/src/LayerFECompositionState.cpp
index 6631a27..a405c4d 100644
--- a/services/surfaceflinger/CompositionEngine/src/LayerFECompositionState.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/LayerFECompositionState.cpp
@@ -106,7 +106,6 @@
dumpVal(out, "composition type", toString(compositionType), compositionType);
out.append("\n buffer: ");
- dumpVal(out, "slot", bufferSlot);
dumpVal(out, "buffer", buffer.get());
out.append("\n ");
diff --git a/services/surfaceflinger/CompositionEngine/src/Output.cpp b/services/surfaceflinger/CompositionEngine/src/Output.cpp
index 3ee8017..16ef812 100644
--- a/services/surfaceflinger/CompositionEngine/src/Output.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/Output.cpp
@@ -428,6 +428,7 @@
ALOGV(__FUNCTION__);
rebuildLayerStacks(refreshArgs, geomSnapshots);
+ uncacheBuffers(refreshArgs.bufferIdsToUncache);
}
void Output::present(const compositionengine::CompositionRefreshArgs& refreshArgs) {
@@ -455,6 +456,15 @@
renderCachedSets(refreshArgs);
}
+void Output::uncacheBuffers(std::vector<uint64_t> const& bufferIdsToUncache) {
+ if (bufferIdsToUncache.empty()) {
+ return;
+ }
+ for (auto outputLayer : getOutputLayersOrderedByZ()) {
+ outputLayer->uncacheBuffers(bufferIdsToUncache);
+ }
+}
+
void Output::rebuildLayerStacks(const compositionengine::CompositionRefreshArgs& refreshArgs,
LayerFESet& layerFESet) {
ATRACE_CALL();
diff --git a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
index a39c527..a7c24b6 100644
--- a/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
+++ b/services/surfaceflinger/CompositionEngine/src/OutputLayer.cpp
@@ -610,6 +610,19 @@
}
}
+void OutputLayer::uncacheBuffers(std::vector<uint64_t> const& bufferIdsToUncache) {
+ auto& state = editState();
+ // Skip doing this if there is no HWC interface
+ if (!state.hwc) {
+ return;
+ }
+
+ for (auto bufferId : bufferIdsToUncache) {
+ state.hwc->hwcBufferCache.uncache(bufferId);
+ // TODO(b/258196272): send uncache requests to Composer HAL
+ }
+}
+
void OutputLayer::writeBufferStateToHWC(HWC2::Layer* hwcLayer,
const LayerFECompositionState& outputIndependentState,
bool skipLayer) {
@@ -622,27 +635,24 @@
to_string(error).c_str(), static_cast<int32_t>(error));
}
- sp<GraphicBuffer> buffer = outputIndependentState.buffer;
- sp<Fence> acquireFence = outputIndependentState.acquireFence;
- int slot = outputIndependentState.bufferSlot;
+ HwcSlotAndBuffer hwcSlotAndBuffer;
+ sp<Fence> hwcFence;
+ // Override buffers use a special cache slot so that they don't evict client buffers.
if (getState().overrideInfo.buffer != nullptr && !skipLayer) {
- buffer = getState().overrideInfo.buffer->getBuffer();
- acquireFence = getState().overrideInfo.acquireFence;
- slot = HwcBufferCache::FLATTENER_CACHING_SLOT;
+ hwcSlotAndBuffer = editState().hwc->hwcBufferCache.getHwcSlotAndBufferForOverride(
+ getState().overrideInfo.buffer->getBuffer());
+ hwcFence = getState().overrideInfo.acquireFence;
+ } else {
+ hwcSlotAndBuffer =
+ editState().hwc->hwcBufferCache.getHwcSlotAndBuffer(outputIndependentState.buffer);
+ hwcFence = outputIndependentState.acquireFence;
}
- ALOGV("Writing buffer %p", buffer.get());
-
- uint32_t hwcSlot = 0;
- sp<GraphicBuffer> hwcBuffer;
- // We need access to the output-dependent state for the buffer cache there,
- // though otherwise the buffer is not output-dependent.
- editState().hwc->hwcBufferCache.getHwcBuffer(slot, buffer, &hwcSlot, &hwcBuffer);
-
- if (auto error = hwcLayer->setBuffer(hwcSlot, hwcBuffer, acquireFence);
+ if (auto error = hwcLayer->setBuffer(hwcSlotAndBuffer.slot, hwcSlotAndBuffer.buffer, hwcFence);
error != hal::Error::NONE) {
- ALOGE("[%s] Failed to set buffer %p: %s (%d)", getLayerFE().getDebugName(), buffer->handle,
- to_string(error).c_str(), static_cast<int32_t>(error));
+ ALOGE("[%s] Failed to set buffer %p: %s (%d)", getLayerFE().getDebugName(),
+ hwcSlotAndBuffer.buffer->handle, to_string(error).c_str(),
+ static_cast<int32_t>(error));
}
}