AMS: added caching DataInputStream object

DataInputStream is cached for the lmkd socket communication
Since the LmkdConnection ByteBuffer is allocated once,
no need to dynamically allocate DataInputStream,
just do a reset() before using

Bug: 184698933
Test: lmkd_unit_test - test check_for_oom tests lmkd message send to AMS
Test: statsd_testdrive 51 54 to inspect statsd logged atoms data
Change-Id: I9b65d82618654d59236c79be8cd8da66bc90c91c

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

@@ -31,6 +31,8 @@ import com.android.internal.annotations.GuardedBy;
 
 import libcore.io.IoUtils;
 
+import java.io.ByteArrayInputStream;
+import java.io.DataInputStream;
 import java.io.FileDescriptor;
 import java.io.IOException;
 import java.io.InputStream;
@@ -74,7 +76,7 @@ public class LmkdConnection {
          * @param receivedLen Size of the data received
          * @return True if the message has been handled correctly, false otherwise.
          */
-        boolean handleUnsolicitedMessage(ByteBuffer dataReceived, int receivedLen);
+        boolean handleUnsolicitedMessage(DataInputStream inputData, int receivedLen);
     }
 
     private final MessageQueue mMsgQueue;
@@ -99,6 +101,10 @@ public class LmkdConnection {
     private final ByteBuffer mInputBuf =
             ByteBuffer.allocate(LMKD_REPLY_MAX_SIZE);
 
+    // Input stream to parse the incoming data
+    private final DataInputStream mInputData = new DataInputStream(
+            new ByteArrayInputStream(mInputBuf.array()));
+
     // object to protect mReplyBuf and to wait/notify when reply is received
     private final Object mReplyBufLock = new Object();
 
@@ -190,26 +196,32 @@ public class LmkdConnection {
     private void processIncomingData() {
         int len = read(mInputBuf);
         if (len > 0) {
-            synchronized (mReplyBufLock) {
+            try {
-                if (mReplyBuf != null) {
+                // reset InputStream to point into mInputBuf.array() begin
-                    if (mListener.isReplyExpected(mReplyBuf, mInputBuf, len)) {
+                mInputData.reset();
-                        // copy into reply buffer
+                synchronized (mReplyBufLock) {
-                        mReplyBuf.put(mInputBuf.array(), 0, len);
+                    if (mReplyBuf != null) {
-                        mReplyBuf.rewind();
+                        if (mListener.isReplyExpected(mReplyBuf, mInputBuf, len)) {
-                        // wakeup the waiting thread
+                            // copy into reply buffer
-                        mReplyBufLock.notifyAll();
+                            mReplyBuf.put(mInputBuf.array(), 0, len);
-                    } else if (!mListener.handleUnsolicitedMessage(mInputBuf, len)) {
+                            mReplyBuf.rewind();
-                        // received unexpected packet
+                            // wakeup the waiting thread
-                        // treat this as an error
+                            mReplyBufLock.notifyAll();
-                        mReplyBuf = null;
+                        } else if (!mListener.handleUnsolicitedMessage(mInputData, len)) {
-                        mReplyBufLock.notifyAll();
+                            // received unexpected packet
-                        Slog.e(TAG, "Received an unexpected packet from lmkd");
+                            // treat this as an error
+                            mReplyBuf = null;
+                            mReplyBufLock.notifyAll();
+                            Slog.e(TAG, "Received an unexpected packet from lmkd");
+                        }
+                    } else if (!mListener.handleUnsolicitedMessage(mInputData, len)) {
+                        // received asynchronous communication from lmkd
+                        // but we don't recognize it.
+                        Slog.w(TAG, "Received an unexpected packet from lmkd");
                     }
-                } else if (!mListener.handleUnsolicitedMessage(mInputBuf, len)) {
-                    // received asynchronous communication from lmkd
-                    // but we don't recognize it.
-                    Slog.w(TAG, "Received an unexpected packet from lmkd");
                 }
+            } catch (IOException e) {
+                Slog.e(TAG, "Failed to parse lmkd data buffer. Size = " + len);
             }
         }
     }

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

@@ -23,10 +23,8 @@ import android.util.Slog;
 
 import com.android.internal.util.FrameworkStatsLog;
 
-import java.io.ByteArrayInputStream;
 import java.io.DataInputStream;
 import java.io.IOException;
-import java.nio.ByteBuffer;
 
 /**
  * Activity manager communication with lmkd data handling and statsd atom logging
@@ -51,13 +49,8 @@ public final class LmkdStatsReporter {
      * Logs the event when LMKD kills a process to reduce memory pressure.
      * Code: LMK_KILL_OCCURRED = 51
      */
-    public static void logKillOccurred(ByteBuffer dataReceived) {
+    public static void logKillOccurred(DataInputStream inputData) {
-        DataInputStream inputData = new DataInputStream(
-                new ByteArrayInputStream(dataReceived.array()));
-
         try {
-            //read first int which denotes the message type
-            final int msgType = inputData.readInt();
             final long pgFault = inputData.readLong();
             final long pgMajFault = inputData.readLong();
             final long rssInBytes = inputData.readLong();

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

@@ -139,6 +139,7 @@ import com.android.server.wm.WindowProcessController;
 
 import dalvik.system.VMRuntime;
 
+import java.io.DataInputStream;
 import java.io.File;
 import java.io.FileDescriptor;
 import java.io.IOException;
@@ -835,37 +836,44 @@ public final class ProcessList {
                         }
 
                         @Override
-                        public boolean handleUnsolicitedMessage(ByteBuffer dataReceived,
+                        public boolean handleUnsolicitedMessage(DataInputStream inputData,
                                 int receivedLen) {
                             if (receivedLen < 4) {
                                 return false;
                             }
 
-                            switch (dataReceived.getInt(0)) {
+                            try {
-                                case LMK_PROCKILL:
+                                switch (inputData.readInt()) {
-                                    if (receivedLen != 12) {
+                                    case LMK_PROCKILL:
+                                        if (receivedLen != 12) {
+                                            return false;
+                                        }
+                                        final int pid = inputData.readInt();
+                                        final int uid = inputData.readInt();
+                                        mAppExitInfoTracker.scheduleNoteLmkdProcKilled(pid, uid);
+                                        return true;
+                                    case LMK_KILL_OCCURRED:
+                                        if (receivedLen
+                                                < LmkdStatsReporter.KILL_OCCURRED_MSG_SIZE) {
+                                            return false;
+                                        }
+                                        LmkdStatsReporter.logKillOccurred(inputData);
+                                        return true;
+                                    case LMK_STATE_CHANGED:
+                                        if (receivedLen
+                                                != LmkdStatsReporter.STATE_CHANGED_MSG_SIZE) {
+                                            return false;
+                                        }
+                                        final int state = inputData.readInt();
+                                        LmkdStatsReporter.logStateChanged(state);
+                                        return true;
+                                    default:
                                         return false;
-                                    }
+                                }
-                                    mAppExitInfoTracker.scheduleNoteLmkdProcKilled(
+                            } catch (IOException e) {
-                                            dataReceived.getInt(4), dataReceived.getInt(8));
+                                Slog.e(TAG, "Invalid buffer data. Failed to log LMK_KILL_OCCURRED");
-                                    return true;
-                                case LMK_KILL_OCCURRED:
-                                    if (receivedLen < LmkdStatsReporter.KILL_OCCURRED_MSG_SIZE) {
-                                        return false;
-                                    }
-                                    dataReceived.position(4);
-                                    LmkdStatsReporter.logKillOccurred(dataReceived);
-                                    return true;
-                                case LMK_STATE_CHANGED:
-                                    if (receivedLen != LmkdStatsReporter.STATE_CHANGED_MSG_SIZE) {
-                                        return false;
-                                    }
-                                    LmkdStatsReporter.logStateChanged(
-                                            dataReceived.getInt(4));
-                                    return true;
-                                default:
-                                    return false;
                             }
+                            return false;
                         }
                     }
             );