Do not block transaction application on flush
Condition wait in applyTransactionState blocks threads sending a
synchronous transaction until SF can commit the transaction. However,
the main SF thread can also applyTransactionState on pending
transactions. In these cases, SF should not be blocked waiting for
itself to commit the transaction.
Bug: 127852667
Test: build, boot, manual
Change-Id: Id6b81529b2f1537ba5ce7aec27789e26225b167b
diff --git a/services/surfaceflinger/SurfaceFlinger.cpp b/services/surfaceflinger/SurfaceFlinger.cpp
index c37028e..42eef04 100644
--- a/services/surfaceflinger/SurfaceFlinger.cpp
+++ b/services/surfaceflinger/SurfaceFlinger.cpp
@@ -3478,7 +3478,7 @@
break;
}
applyTransactionState(states, displays, flags, mPendingInputWindowCommands,
- desiredPresentTime, postTime, privileged);
+ desiredPresentTime, postTime, privileged, /*isMainThread*/ true);
transactionQueue.pop();
}
@@ -3565,7 +3565,7 @@
const Vector<DisplayState>& displays, uint32_t flags,
const InputWindowCommands& inputWindowCommands,
const int64_t desiredPresentTime, const int64_t postTime,
- bool privileged) {
+ bool privileged, bool isMainThread) {
uint32_t transactionFlags = 0;
if (flags & eAnimation) {
@@ -3629,7 +3629,12 @@
}
mPendingSyncInputWindows = mPendingInputWindowCommands.syncInputWindows;
- while (mTransactionPending || mPendingSyncInputWindows) {
+
+ // applyTransactionState can be called by either the main SF thread or by
+ // another process through setTransactionState. While a given process may wish
+ // to wait on synchronous transactions, the main SF thread should never
+ // be blocked. Therefore, we only wait if isMainThread is false.
+ while (!isMainThread && (mTransactionPending || mPendingSyncInputWindows)) {
status_t err = mTransactionCV.waitRelative(mStateLock, s2ns(5));
if (CC_UNLIKELY(err != NO_ERROR)) {
// just in case something goes wrong in SF, return to the