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Commit 44444444 authored by Alex Klyubin's avatar Alex Klyubin
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Move EntropyMixer I/O from main thread to I/O thread 

This moves EntropyMixer I/O from the main thread to the I/O thread to
avoid blocking the main thread. The only time EntropyMixer performs
I/O on the main thread is during initialization of EntropyMixer which
occurs only during startup of SystemServer.

Test: manual: locally modified writeEntropy to log thread name and
      observed that writeEntropy is invoked only on the I/O thread
      ("android.io") except when invoked by EntropyMixer constructor.
Test: atest com.android.server.EntropyMixerTest
Bug: 70471586

Change-Id: Ic9f07f1c65583bb57d3095f9f8e7dde4ea6ae07d
parent a22a7c2f

services/core/java/com/android/server/EntropyMixer.java

+10 −2
Original line number Diff line number Diff line
@@ -70,7 +70,10 @@ public class EntropyMixer extends Binder { 
    /**

     * Handler that periodically updates the entropy on disk.

     */

    private final Handler mHandler = new Handler() {

    private final Handler mHandler = new Handler(IoThread.getHandler().getLooper()) {

        // IMPLEMENTATION NOTE: This handler runs on the I/O thread to avoid I/O on the main thread.

        // The reason we're using our own Handler instead of IoThread.getHandler() is to create our

        // own ID space for the "what" parameter of messages seen by the handler.

        @Override

        public void handleMessage(Message msg) {

            if (msg.what != ENTROPY_WHAT) {
@@ -115,7 +118,12 @@ public class EntropyMixer extends Binder { 
        IntentFilter broadcastFilter = new IntentFilter(Intent.ACTION_SHUTDOWN);

        broadcastFilter.addAction(Intent.ACTION_POWER_CONNECTED);

        broadcastFilter.addAction(Intent.ACTION_REBOOT);

        context.registerReceiver(mBroadcastReceiver, broadcastFilter);

        context.registerReceiver(

                mBroadcastReceiver,

                broadcastFilter,

                null, // do not require broadcaster to hold any permissions

                mHandler // process received broadcasts on the I/O thread instead of the main thread

                );

    }



    private void scheduleEntropyWriter() {