From 7e12b6d8489f68a43b0afb5111a6cfcddb350679 Mon Sep 17 00:00:00 2001
From: Jorim Jaggi <jjaggi@google.com>
Date: Fri, 9 Jun 2017 12:00:58 -0700
Subject: [PATCH] Fix thread booster

We need to conditionally set the prevPriority only if we enter
the first locked section. Otherwise we'll never reset back to the
lower priorities.

Test: Make sure no binder threads are stuck at 110.
Test: go/wm-smoke
Bug: 36631902
Change-Id: I8a9c329bc3084371022da91eabee45943c1b8c9f
---
 .../java/com/android/server/ThreadPriorityBooster.java    | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/services/core/java/com/android/server/ThreadPriorityBooster.java b/services/core/java/com/android/server/ThreadPriorityBooster.java
index 0dfecc051a2d5..cc9ac0dfd11e6 100644
--- a/services/core/java/com/android/server/ThreadPriorityBooster.java
+++ b/services/core/java/com/android/server/ThreadPriorityBooster.java
@@ -43,9 +43,11 @@ public class ThreadPriorityBooster {
         final int tid = myTid();
         final int prevPriority = getThreadPriority(tid);
         final PriorityState state = mThreadState.get();
-        state.prevPriority = prevPriority;
-        if (state.regionCounter == 0 && prevPriority > mBoostToPriority) {
-            setThreadPriority(tid, mBoostToPriority);
+        if (state.regionCounter == 0) {
+            state.prevPriority = prevPriority;
+            if (prevPriority > mBoostToPriority) {
+                setThreadPriority(tid, mBoostToPriority);
+            }
         }
         state.regionCounter++;
         if (LockGuard.ENABLED) {