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Commit d6e67e6a authored by Alan Leung's avatar Alan Leung
Browse files

Fix thread priority after boosting. 

The previous CL wrongly restores all priority to nice 0.

This CL changes two things:

1. It remembers and restores the previous priority.
2. If the thread has priority of < -2. Do not set it to -2.

BUG: 29930920
Change-Id: I927e060d789c9bbf92f6a166f44317d9db0f5205
parent 87df5f6d

services/core/java/com/android/server/am/ActivityManagerService.java

+25 −14
Original line number Diff line number Diff line
@@ -644,30 +644,41 @@ public final class ActivityManagerService extends ActivityManagerNative 
        return mShowDialogs && !mSleeping && !mShuttingDown;

    }













    // it's a semaphore; boost when 0->1, reset when 1->0













    static ThreadLocal<Integer> sIsBoosted = new ThreadLocal<Integer>() {













        @Override protected Integer initialValue() {













            return 0;













    private static final class PriorityState {













        // Acts as counter for number of synchronized region that needs to acquire 'this' as a lock













        // the current thread is currently in. When it drops down to zero, we will no longer boost













        // the thread's priority.













        private int regionCounter = 0;

























        // The thread's previous priority before boosting.













        private int prevPriority = Integer.MIN_VALUE;













    }

























    static ThreadLocal<PriorityState> sThreadPriorityState = new ThreadLocal<PriorityState>() {













        @Override protected PriorityState initialValue() {













            return new PriorityState();















        }















    };





























    static void boostPriorityForLockedSection() {













        if (sIsBoosted.get() == 0) {













            // boost to prio 118 while holding a global lock













            Process.setThreadPriority(Process.myTid(), -2);













            //Log.e(TAG, "PRIORITY BOOST:  set priority on TID " + Process.myTid());













        int tid = Process.myTid();













        int prevPriority = Process.getThreadPriority(tid);













        PriorityState state = sThreadPriorityState.get();













        if (state.regionCounter == 0 && prevPriority > -2) {













            state.prevPriority = prevPriority;













            Process.setThreadPriority(tid, -2);















        }













        int cur = sIsBoosted.get();













        sIsBoosted.set(cur + 1);













        state.regionCounter++;















    }





























    static void resetPriorityAfterLockedSection() {













        sIsBoosted.set(sIsBoosted.get() - 1);













        if (sIsBoosted.get() == 0) {













            //Log.e(TAG, "PRIORITY BOOST:  reset priority on TID " + Process.myTid());













            Process.setThreadPriority(Process.myTid(), 0);













        PriorityState state = sThreadPriorityState.get();













        state.regionCounter--;













        if (state.regionCounter == 0 && state.prevPriority > -2) {













            Process.setThreadPriority(Process.myTid(), state.prevPriority);















        }















    }



























    public class PendingAssistExtras extends Binder implements Runnable {















        public final ActivityRecord activity;















        public final Bundle extras;