Merge "Do not do heapSweep on message removal" into main (29f29ff9) · Commits · e / os / android_frameworks_base

core/java/android/os/MessageStack.java

+19 −5

Original line number	Diff line number	Diff line
		@@ -251,6 +251,17 @@ public final class MessageStack {
		return m;
		}

		/**
		* Create all missing backlinks in the stack.
		*/
		private void createBackLinks() {
		Message current = (Message) sTop.getAcquire(this);
		while (current != null && current.next != null && current.next.prev == null) {
		current.next.prev = current;
		current = current.next;
		}
		}

		/**
		* Remove a message from the stack.
		*
		@@ -275,8 +286,10 @@ public final class MessageStack {
		mLooperProcessed = mLooperProcessed.next;
		} while (mLooperProcessed != null && mLooperProcessed.isRemoved());
		}
		// If this is the top, attempt to CAS the top to the next item.
		if (m == mTopValue) {

		// If prev is null, m was the top at the time the previous heapSweep was called.
		if (m.prev == null) {
		// Check whether m is still the top. If so, we can just unlink it.
		// Since only the looper thread can pop or drain the freelist, if this CAS fails, it
		// can only be due to a push or quit.
		if (sTop.compareAndSet(this, m, m.next)) {
		@@ -284,9 +297,10 @@ public final class MessageStack {
		m.prev = null;
		return;
		}
		// If the CAS failed, this is no longer the top, and we must find m's predecessor and
		// create backlinks before continuing to remove the message the normal way.
		heapSweep();
		// New messages are pushed to the stack between the previous heapSweep and now.
		// We must find m's predecessor and create backlinks before continuing to
		// remove the message the normal way.
		createBackLinks();
		}
		unlinkFromNext(m);
		unlinkFromPrev(m);