Fix issues with GC thread.

bug 8600533

Change-Id: I356902ee9897daeb2c1090815beeb572234c81e7

graphics/java/android/renderscript/RenderScript.java

@@ -18,7 +18,9 @@ package android.renderscript;
 
 import java.io.File;
 import java.lang.reflect.Field;
+import java.util.concurrent.locks.*;
 
+import android.app.ActivityManager;
 import android.content.Context;
 import android.content.pm.ApplicationInfo;
 import android.content.pm.PackageManager;
@@ -1042,8 +1044,11 @@ public class RenderScript {
         RenderScript mRS;
         boolean mRun = true;
 
-        int currentSize = 0;
-        final static int targetSize = 256*1024*1024; // call System.gc after 256MB of allocs
+        long currentSize = 0;
+        long targetSize; // call System.gc after 512MB of allocs
+
+        final Lock lock = new ReentrantLock();
+        final Condition cond = lock.newCondition();
 
         GCThread(RenderScript rs) {
             super("RSGCThread");
@@ -1052,29 +1057,37 @@ public class RenderScript {
         }
 
         public void run() {
+            ActivityManager am = (ActivityManager)mRS.getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
+            ActivityManager.MemoryInfo meminfo = new ActivityManager.MemoryInfo();
+            am.getMemoryInfo(meminfo);
+            targetSize = (long)(meminfo.totalMem * .5f);
+
             while(mRun) {
-                boolean doGC = false;
-                synchronized(this) {
-                    if (currentSize >= targetSize) {
-                        doGC = true;
-                    }
-                }
-                if (doGC == true) {
-                    System.gc();
-                }
+                System.gc();
+                lock.lock();
                 try {
-                    sleep(1, 0);
-                } catch(InterruptedException e) {
+                    cond.awaitUninterruptibly();
+                } finally {
+                    lock.unlock();
                 }
             }
+
             Log.d(LOG_TAG, "GCThread exiting.");
         }
 
-        public synchronized void addAllocSize(int bytes) {
+        public synchronized void addAllocSize(long bytes) {
             currentSize += bytes;
+            if (currentSize >= targetSize) {
+                lock.lock();
+                try {
+                    cond.signal();
+                } finally {
+                    lock.unlock();
+                }
+            }
         }
 
-        public synchronized void removeAllocSize(int bytes) {
+        public synchronized void removeAllocSize(long bytes) {
             currentSize -= bytes;
         }
 
@@ -1186,6 +1199,7 @@ public class RenderScript {
         nContextDeinitToClient(mContext);
         mMessageThread.mRun = false;
         mGCThread.mRun = false;
+        mGCThread.addAllocSize(0);
         try {
             mMessageThread.join();
             mGCThread.join();