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Merge "ViewRootImpl: Fix overlapping BLAST Sync issues."

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This commit is contained in:
Rob Carr
2020-02-18 22:28:17 +00:00
committed by Android (Google) Code Review
parent 65ac963706 2bd95bf6ad
commit d201386460
1 changed files with 31 additions and 5 deletions
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36
core/java/android/view/ViewRootImpl.java
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@@ -666,7 +666,22 @@ public final class ViewRootImpl implements ViewParent,
int localChanges;
}
// If set, ViewRootImpl will call BLASTBufferQueue::setNextTransaction with
// mRtBLASTSyncTransaction, prior to invoking draw. This provides a way
// to redirect the buffers in to transactions.
private boolean mNextDrawUseBLASTSyncTransaction;
// Set when calling setNextTransaction, we can't just reuse mNextDrawUseBLASTSyncTransaction
// because, imagine this scenario:
// 1. First draw is using BLAST, mNextDrawUseBLAST = true
// 2. We call perform draw and are waiting on the callback
// 3. After the first perform draw but before the first callback and the
// second perform draw, a second draw sets mNextDrawUseBLAST = true (it already was)
// 4. At this point the callback fires and we set mNextDrawUseBLAST = false;
// 5. We get to performDraw and fail to sync as we intended because mNextDrawUseBLAST
// is now false.
// This is why we use a two-step latch with the two booleans, one consumed from
// performDraw and one consumed from finishBLASTSync()
private boolean mNextReportConsumeBLAST;
// Be very careful with the threading here. This is used from the render thread while
// the UI thread is paused and then applied and cleared from the UI thread right after
// draw returns.
@@ -3719,9 +3734,9 @@ public final class ViewRootImpl implements ViewParent,
usingAsyncReport = mReportNextDraw;
if (needFrameCompleteCallback) {
final Handler handler = mAttachInfo.mHandler;
mAttachInfo.mThreadedRenderer.setFrameCompleteCallback((long frameNr) ->
mAttachInfo.mThreadedRenderer.setFrameCompleteCallback((long frameNr) -> {
finishBLASTSync();
handler.postAtFrontOfQueue(() -> {
finishBLASTSync();
if (reportNextDraw) {
// TODO: Use the frame number
pendingDrawFinished();
@@ -3731,12 +3746,23 @@ public final class ViewRootImpl implements ViewParent,
commitCallbacks.get(i).run();
}
}
}));
});});
}
}
try {
if (mNextDrawUseBLASTSyncTransaction) {
// TODO(b/149747443)
// We aren't prepared to handle overlapping use of mRtBLASTSyncTransaction
// so if we are BLAST syncing we make sure the previous draw has
// totally finished.
if (mAttachInfo.mThreadedRenderer != null) {
mAttachInfo.mThreadedRenderer.fence();
}
mNextReportConsumeBLAST = true;
mNextDrawUseBLASTSyncTransaction = false;
mBlastBufferQueue.setNextTransaction(mRtBLASTSyncTransaction);
}
boolean canUseAsync = draw(fullRedrawNeeded);
@@ -9556,8 +9582,8 @@ public final class ViewRootImpl implements ViewParent,
}
private void finishBLASTSync() {
if (mNextDrawUseBLASTSyncTransaction) {
mNextDrawUseBLASTSyncTransaction = false;
if (mNextReportConsumeBLAST) {
mNextReportConsumeBLAST = false;
mRtBLASTSyncTransaction.apply();
}
}