BLASTBufferQueue: Handler allocateBuffers on thread.

allocateBuffers is a one-way method in the IGBP interface. In
the non-BLAST case the IGBP is hosted in SF and allocateBuffers
is therefore a one-way binder call executed asynchronously on an
SF binder thread. In the BLAST case the IGBP will be in process and so
allocateBuffers will execute in a blocking fashion. Callers don't like
being blocked when they weren't before, so we want to emulate this
behavior in BLASTBufferQueue. We introduce a Surface subclass
(BBQSurface) which overrides allocateBuffers and pushes the operation to
a new thread.

Bug: 168504871
Test: asit/perf/appstartup_all_apps_cyclic_dropcache_test . Enabling
BLAST triggers regression, but applying this removes the regression.

Change-Id: If6bb411e021ba2e0886dfe96b1a1a1489e3627b8

1 files changed, 23 insertions, 0 deletions

diff --git a/libs/gui/BLASTBufferQueue.cpp b/libs/gui/BLASTBufferQueue.cpp
index 0b942199c3..82c963be7b 100644
--- a/libs/gui/BLASTBufferQueue.cpp
+++ b/libs/gui/BLASTBufferQueue.cpp
@@ -23,6 +23,7 @@
 #include <gui/BLASTBufferQueue.h>
 #include <gui/BufferItemConsumer.h>
 #include <gui/GLConsumer.h>
+#include <gui/Surface.h>
 
 #include <utils/Trace.h>
 
@@ -352,4 +353,26 @@ bool BLASTBufferQueue::maxBuffersAcquired() const {
             (!mInitialCallbackReceived && mNumAcquired == 1);
 }
 
+class BBQSurface : public Surface {
+public:
+    BBQSurface(const sp<IGraphicBufferProducer>& igbp, bool controlledByApp) :
+        Surface(igbp, controlledByApp) {
+    }
+    void allocateBuffers() override {
+        uint32_t reqWidth = mReqWidth ? mReqWidth : mUserWidth;
+        uint32_t reqHeight = mReqHeight ? mReqHeight : mUserHeight;
+        auto gbp = getIGraphicBufferProducer();
+        std::thread ([reqWidth, reqHeight, gbp=getIGraphicBufferProducer(),
+                      reqFormat=mReqFormat, reqUsage=mReqUsage] () {
+            gbp->allocateBuffers(reqWidth, reqHeight,
+                                 reqFormat, reqUsage);
+
+        }).detach();
+    }
+};
+
+sp<Surface> BLASTBufferQueue::getSurface() {
+    return new BBQSurface(mProducer, true);
+}
+
 } // namespace android