freezer: reentrant enable/disable method
the app freezer state can be toggled in multiple situations when a
debugging tool like heapdump is invoked, or when system_server dumps its
binder connections. All these uses are potentially concurrent and a
robust method to handle reentrancy is necessary to avoid leaving the
freezer in a state incompatible with a specific operation.
This patch moves freezer enable and disable operations from Process to
CachedAppOptimizer (ActivityManager), introduces a new ActivityManager API
to centralize all freezer state changes to ActivityManager and modifies
client code accordingly.
Bug: 151225245
Test: manually verified that no regression are introduced on freezer
behavior, verified that concurrent behavior is handled properly
Change-Id: I7d588cc6e0499012dce64ed4e42ff2adb336062d
Merged-In: I7d588cc6e0499012dce64ed4e42ff2adb336062d
diff --git a/core/java/android/app/IActivityManager.aidl b/core/java/android/app/IActivityManager.aidl
index 2abe9cf..f98e263 100644
--- a/core/java/android/app/IActivityManager.aidl
+++ b/core/java/android/app/IActivityManager.aidl
@@ -684,4 +684,14 @@
* Kills uid with the reason of permission change.
*/
void killUidForPermissionChange(int appId, int userId, String reason);
+
+ /**
+ * Control the app freezer state. Returns true in case of success, false if the operation
+ * didn't succeed (for example, when the app freezer isn't supported).
+ * Handling the freezer state via this method is reentrant, that is it can be
+ * disabled and re-enabled multiple times in parallel. As long as there's a 1:1 disable to
+ * enable match, the freezer is re-enabled at last enable only.
+ * @param enable set it to true to enable the app freezer, false to disable it.
+ */
+ boolean enableAppFreezer(in boolean enable);
}
diff --git a/core/java/android/os/BinderProxy.java b/core/java/android/os/BinderProxy.java
index 683993f7..0185ba4 100644
--- a/core/java/android/os/BinderProxy.java
+++ b/core/java/android/os/BinderProxy.java
@@ -18,6 +18,7 @@
import android.annotation.NonNull;
import android.annotation.Nullable;
+import android.app.ActivityManager;
import android.app.AppOpsManager;
import android.util.Log;
import android.util.SparseIntArray;
@@ -255,7 +256,12 @@
// out of system_server to all processes hosting binder objects it holds a reference to;
// since some of those processes might be frozen, we don't want to block here
// forever. Disable the freezer.
- Process.enableFreezer(false);
+ try {
+ ActivityManager.getService().enableAppFreezer(false);
+ } catch (RemoteException e) {
+ Log.e(Binder.TAG, "RemoteException while disabling app freezer");
+ }
+
for (WeakReference<BinderProxy> weakRef : proxiesToQuery) {
BinderProxy bp = weakRef.get();
String key;
@@ -278,7 +284,11 @@
counts.put(key, i + 1);
}
}
- Process.enableFreezer(true);
+ try {
+ ActivityManager.getService().enableAppFreezer(true);
+ } catch (RemoteException e) {
+ Log.e(Binder.TAG, "RemoteException while re-enabling app freezer");
+ }
Map.Entry<String, Integer>[] sorted = counts.entrySet().toArray(
new Map.Entry[counts.size()]);
diff --git a/core/jni/android_util_Process.cpp b/core/jni/android_util_Process.cpp
index 3486a85..6becb07 100644
--- a/core/jni/android_util_Process.cpp
+++ b/core/jni/android_util_Process.cpp
@@ -346,22 +346,6 @@
}
}
-void android_os_Process_enableFreezer(
- JNIEnv *env, jobject clazz, jboolean enable)
-{
- bool success = true;
-
- if (enable) {
- success = SetTaskProfiles(0, {"FreezerEnabled"}, true);
- } else {
- success = SetTaskProfiles(0, {"FreezerDisabled"}, true);
- }
-
- if (!success) {
- jniThrowException(env, "java/lang/RuntimeException", "Unknown error");
- }
-}
-
jint android_os_Process_getProcessGroup(JNIEnv* env, jobject clazz, jint pid)
{
SchedPolicy sp;
@@ -1360,7 +1344,6 @@
{"sendSignal", "(II)V", (void*)android_os_Process_sendSignal},
{"sendSignalQuiet", "(II)V", (void*)android_os_Process_sendSignalQuiet},
{"setProcessFrozen", "(IIZ)V", (void*)android_os_Process_setProcessFrozen},
- {"enableFreezer", "(Z)V", (void*)android_os_Process_enableFreezer},
{"getFreeMemory", "()J", (void*)android_os_Process_getFreeMemory},
{"getTotalMemory", "()J", (void*)android_os_Process_getTotalMemory},
{"readProcLines", "(Ljava/lang/String;[Ljava/lang/String;[J)V",
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 44e3bbf..491579a 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -2218,17 +2218,13 @@
@Override
protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
try {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(false);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(false);
if (!DumpUtils.checkDumpAndUsageStatsPermission(mActivityManagerService.mContext,
"meminfo", pw)) return;
PriorityDump.dump(mPriorityDumper, fd, pw, args);
} finally {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(true);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(true);
}
}
}
@@ -2242,17 +2238,13 @@
@Override
protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
try {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(false);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(false);
if (!DumpUtils.checkDumpAndUsageStatsPermission(mActivityManagerService.mContext,
"gfxinfo", pw)) return;
mActivityManagerService.dumpGraphicsHardwareUsage(fd, pw, args);
} finally {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(true);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(true);
}
}
}
@@ -2266,17 +2258,13 @@
@Override
protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
try {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(false);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(false);
if (!DumpUtils.checkDumpAndUsageStatsPermission(mActivityManagerService.mContext,
"dbinfo", pw)) return;
mActivityManagerService.dumpDbInfo(fd, pw, args);
} finally {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(true);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(true);
}
}
}
@@ -2322,9 +2310,7 @@
@Override
protected void dump(FileDescriptor fd, PrintWriter pw, String[] args) {
try {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(false);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(false);
if (!DumpUtils.checkDumpAndUsageStatsPermission(mActivityManagerService.mContext,
"cacheinfo", pw)) {
@@ -2333,9 +2319,7 @@
mActivityManagerService.dumpBinderCacheContents(fd, pw, args);
} finally {
- if (mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.useFreezer()) {
- Process.enableFreezer(true);
- }
+ mActivityManagerService.mOomAdjuster.mCachedAppOptimizer.enableFreezer(true);
}
}
}
@@ -18630,14 +18614,14 @@
}
}
- Process.enableFreezer(false);
+ mOomAdjuster.mCachedAppOptimizer.enableFreezer(false);
final RemoteCallback intermediateCallback = new RemoteCallback(
new RemoteCallback.OnResultListener() {
@Override
public void onResult(Bundle result) {
finishCallback.sendResult(result);
- Process.enableFreezer(true);
+ mOomAdjuster.mCachedAppOptimizer.enableFreezer(true);
}
}, null);
@@ -20399,4 +20383,16 @@
Binder.restoreCallingIdentity(token);
}
}
+
+ @Override
+ public boolean enableAppFreezer(boolean enable) {
+ int callerUid = Binder.getCallingUid();
+
+ // Only system can toggle the freezer state
+ if (callerUid == SYSTEM_UID) {
+ return mOomAdjuster.mCachedAppOptimizer.enableFreezer(enable);
+ } else {
+ throw new SecurityException("Caller uid " + callerUid + " cannot set freezer state ");
+ }
+ }
}
diff --git a/services/core/java/com/android/server/am/CachedAppOptimizer.java b/services/core/java/com/android/server/am/CachedAppOptimizer.java
index ce7c73a..c5047e5 100644
--- a/services/core/java/com/android/server/am/CachedAppOptimizer.java
+++ b/services/core/java/com/android/server/am/CachedAppOptimizer.java
@@ -208,6 +208,8 @@
@GuardedBy("mPhenotypeFlagLock")
private volatile boolean mUseCompaction = DEFAULT_USE_COMPACTION;
private volatile boolean mUseFreezer = DEFAULT_USE_FREEZER;
+ @GuardedBy("this")
+ private int mFreezerDisableCount = 1; // Freezer is initially disabled, until enabled
private final Random mRandom = new Random();
@GuardedBy("mPhenotypeFlagLock")
@VisibleForTesting volatile float mCompactStatsdSampleRate = DEFAULT_STATSD_SAMPLE_RATE;
@@ -420,6 +422,63 @@
}
/**
+ * Enables or disabled the app freezer.
+ * @param enable Enables the freezer if true, disables it if false.
+ * @return true if the operation completed successfully, false otherwise.
+ */
+ public synchronized boolean enableFreezer(boolean enable) {
+ if (!mUseFreezer) {
+ return false;
+ }
+
+ if (enable) {
+ mFreezerDisableCount--;
+
+ if (mFreezerDisableCount > 0) {
+ return true;
+ } else if (mFreezerDisableCount < 0) {
+ Slog.e(TAG_AM, "unbalanced call to enableFreezer, ignoring");
+ mFreezerDisableCount = 0;
+ return false;
+ }
+ } else {
+ mFreezerDisableCount++;
+
+ if (mFreezerDisableCount > 1) {
+ return true;
+ }
+ }
+
+ try {
+ enableFreezerInternal(enable);
+ return true;
+ } catch (java.lang.RuntimeException e) {
+ if (enable) {
+ mFreezerDisableCount = 0;
+ } else {
+ mFreezerDisableCount = 1;
+ }
+
+ Slog.e(TAG_AM, "Exception handling freezer state (enable: " + enable + "): "
+ + e.toString());
+ }
+
+ return false;
+ }
+
+ /**
+ * Enable or disable the freezer. When enable == false all frozen processes are unfrozen,
+ * but aren't removed from the freezer. While in this state, processes can be added or removed
+ * by using Process.setProcessFrozen(), but they wouldn't be actually frozen until the freezer
+ * is enabled. If enable == true all processes in the freezer are frozen.
+ *
+ * @param enable Specify whether to enable (true) or disable (false) the freezer.
+ *
+ * @hide
+ */
+ private static native void enableFreezerInternal(boolean enable);
+
+ /**
* Determines whether the freezer is supported by this system
*/
public static boolean isFreezerSupported() {
@@ -471,7 +530,7 @@
if (mUseFreezer && mFreezeHandler == null) {
Slog.d(TAG_AM, "Freezer enabled");
- Process.enableFreezer(true);
+ enableFreezer(true);
if (!mCachedAppOptimizerThread.isAlive()) {
mCachedAppOptimizerThread.start();
@@ -482,7 +541,7 @@
Process.setThreadGroupAndCpuset(mCachedAppOptimizerThread.getThreadId(),
Process.THREAD_GROUP_SYSTEM);
} else {
- Process.enableFreezer(false);
+ enableFreezer(false);
}
}
diff --git a/services/core/jni/Android.bp b/services/core/jni/Android.bp
index 925ad0f..460842e 100644
--- a/services/core/jni/Android.bp
+++ b/services/core/jni/Android.bp
@@ -106,6 +106,7 @@
"libkeystore_binder",
"libmtp",
"libnativehelper",
+ "libprocessgroup",
"libutils",
"libui",
"libinput",
diff --git a/services/core/jni/com_android_server_am_CachedAppOptimizer.cpp b/services/core/jni/com_android_server_am_CachedAppOptimizer.cpp
index 6a6da0e..7e9e11d 100644
--- a/services/core/jni/com_android_server_am_CachedAppOptimizer.cpp
+++ b/services/core/jni/com_android_server_am_CachedAppOptimizer.cpp
@@ -30,6 +30,7 @@
#include <nativehelper/JNIHelp.h>
#include <android_runtime/AndroidRuntime.h>
#include <jni.h>
+#include <processgroup/processgroup.h>
using android::base::StringPrintf;
using android::base::WriteStringToFile;
@@ -74,9 +75,26 @@
}
}
+static void com_android_server_am_CachedAppOptimizer_enableFreezerInternal(
+ JNIEnv *env, jobject clazz, jboolean enable) {
+ bool success = true;
+
+ if (enable) {
+ success = SetTaskProfiles(0, {"FreezerEnabled"}, true);
+ } else {
+ success = SetTaskProfiles(0, {"FreezerDisabled"}, true);
+ }
+
+ if (!success) {
+ jniThrowException(env, "java/lang/RuntimeException", "Unknown error");
+ }
+}
+
static const JNINativeMethod sMethods[] = {
/* name, signature, funcPtr */
{"compactSystem", "()V", (void*)com_android_server_am_CachedAppOptimizer_compactSystem},
+ {"enableFreezerInternal", "(Z)V",
+ (void*)com_android_server_am_CachedAppOptimizer_enableFreezerInternal},
};
int register_android_server_am_CachedAppOptimizer(JNIEnv* env)
