7 files changed, 133 insertions, 0 deletions
diff --git a/runtime/monitor.cc b/runtime/monitor.cc
index 9c0927584e..071b0e2c75 100644
--- a/runtime/monitor.cc
+++ b/runtime/monitor.cc
@@ -1394,6 +1394,12 @@ void MonitorList::SweepMonitorList(IsMarkedVisitor* visitor) {
   }
 }
 
+size_t MonitorList::Size() {
+  Thread* self = Thread::Current();
+  MutexLock mu(self, monitor_list_lock_);
+  return list_.size();
+}
+
 class MonitorDeflateVisitor : public IsMarkedVisitor {
  public:
   MonitorDeflateVisitor() : self_(Thread::Current()), deflate_count_(0) {}
diff --git a/runtime/monitor.h b/runtime/monitor.h
index c3da5636ad..1fa46826eb 100644
--- a/runtime/monitor.h
+++ b/runtime/monitor.h
@@ -331,6 +331,7 @@ class MonitorList {
   void BroadcastForNewMonitors() REQUIRES(!monitor_list_lock_);
   // Returns how many monitors were deflated.
   size_t DeflateMonitors() REQUIRES(!monitor_list_lock_) REQUIRES(Locks::mutator_lock_);
+  size_t Size() REQUIRES(!monitor_list_lock_);
 
   typedef std::list<Monitor*, TrackingAllocator<Monitor*, kAllocatorTagMonitorList>> Monitors;
 
diff --git a/test/596-monitor-inflation/expected.txt b/test/596-monitor-inflation/expected.txt
new file mode 100644
index 0000000000..2add6966a0
--- /dev/null
+++ b/test/596-monitor-inflation/expected.txt
@@ -0,0 +1,6 @@
+JNI_OnLoad called
+Monitor list grew by at least 4000 monitors
+Monitor list shrank correctly
+Finished first check
+Finished second check
+Total checks: 10000
diff --git a/test/596-monitor-inflation/info.txt b/test/596-monitor-inflation/info.txt
new file mode 100644
index 0000000000..81dedb60aa
--- /dev/null
+++ b/test/596-monitor-inflation/info.txt
@@ -0,0 +1,5 @@
+A simple test that forces many monitors to be inflated, while checking
+that hashcodes are consistently maintained.
+
+This allocates more monitors and hence may exercise the monitor pool
+differently, and with more context, than the monitor_pool_test gtest.
diff --git a/test/596-monitor-inflation/monitor_inflation.cc b/test/596-monitor-inflation/monitor_inflation.cc
new file mode 100644
index 0000000000..fb4275b711
--- /dev/null
+++ b/test/596-monitor-inflation/monitor_inflation.cc
@@ -0,0 +1,35 @@
+/*
+ * Copyright (C) 2017 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "gc/heap.h"
+#include "jni.h"
+#include "monitor.h"
+#include "runtime.h"
+#include "thread-inl.h"
+
+namespace art {
+namespace {
+
+extern "C" JNIEXPORT void JNICALL Java_Main_trim(JNIEnv*, jclass) {
+  Runtime::Current()->GetHeap()->Trim(Thread::Current());
+}
+
+extern "C" JNIEXPORT jint JNICALL Java_Main_monitorListSize(JNIEnv*, jclass) {
+  return Runtime::Current()->GetMonitorList()->Size();
+}
+
+}  // namespace
+}  // namespace art
diff --git a/test/596-monitor-inflation/src/Main.java b/test/596-monitor-inflation/src/Main.java
new file mode 100644
index 0000000000..d97c7667e9
--- /dev/null
+++ b/test/596-monitor-inflation/src/Main.java
@@ -0,0 +1,79 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+import java.util.IdentityHashMap;
+import dalvik.system.VMRuntime;
+
+public class Main {
+  public static void main(String[] args) {
+    System.loadLibrary(args[0]);
+    int initialSize = monitorListSize();
+    IdentityHashMap<Object, Integer> all = new IdentityHashMap();
+    for (int i = 0; i < 5000; ++i) {
+      Object obj = new Object();
+      synchronized(obj) {
+        // Should force inflation.
+        all.put(obj, obj.hashCode());
+      }
+    }
+    // Since monitor deflation is delayed significantly, we believe that even with an intervening
+    // GC, monitors should remain inflated.  We allow some slop for unrelated concurrent runtime
+    // actions.
+    int inflatedSize = monitorListSize();
+    if (inflatedSize >= initialSize + 4000) {
+        System.out.println("Monitor list grew by at least 4000 monitors");
+    } else {
+        System.out.println("Monitor list did not grow as expected");
+    }
+    // Encourage monitor deflation.
+    // trim() (Heap::Trim()) deflates only in JANK_IMPERCEPTIBLE state.
+    // Some of this mirrors code in ActivityThread.java.
+    final int DALVIK_PROCESS_STATE_JANK_PERCEPTIBLE = 0;
+    final int DALVIK_PROCESS_STATE_JANK_IMPERCEPTIBLE = 1;
+    VMRuntime.getRuntime().updateProcessState(DALVIK_PROCESS_STATE_JANK_IMPERCEPTIBLE);
+    System.gc();
+    System.runFinalization();
+    trim();
+    VMRuntime.getRuntime().updateProcessState(DALVIK_PROCESS_STATE_JANK_PERCEPTIBLE);
+    int finalSize = monitorListSize();
+    if (finalSize > initialSize + 1000) {
+        System.out.println("Monitor list failed to shrink properly");
+    } else {
+        System.out.println("Monitor list shrank correctly");
+    }
+    int j = 0;
+    for (Object obj: all.keySet()) {
+      ++j;
+      if (obj.hashCode() != all.get(obj)) {
+        throw new AssertionError("Failed hashcode test!");
+      }
+    }
+    System.out.println("Finished first check");
+    for (Object obj: all.keySet()) {
+      ++j;
+      synchronized(obj) {
+        if (obj.hashCode() != all.get(obj)) {
+          throw new AssertionError("Failed hashcode test!");
+        }
+      }
+    }
+    System.out.println("Finished second check");
+    System.out.println("Total checks: " + j);
+  }
+
+  private static native void trim();
+
+  private static native int monitorListSize();
+}
diff --git a/test/Android.bp b/test/Android.bp
index 965d07aa43..e820d28fa1 100644
--- a/test/Android.bp
+++ b/test/Android.bp
@@ -325,6 +325,7 @@ cc_defaults {
         "570-checker-osr/osr.cc",
         "595-profile-saving/profile-saving.cc",
         "596-app-images/app_images.cc",
+        "596-monitor-inflation/monitor_inflation.cc",
         "597-deopt-new-string/deopt.cc",
         "626-const-class-linking/clear_dex_cache_types.cc",
     ],