Lower-overhead version of LockGuard.
Instead of building up a giant set of all locks inside the system
server, there are only a handful that we're interested in watching:
specifically those below the ActivityManagerService lock.
This change adds a index-based variant of lock registering and
checking, which has much lower overhead that doesn't bring a device
to its knees. It's disabled by default, but can be enabled on local
development builds.
Currently uses the boostPriorityForLockedSection() hook in AMS to
check for lock inversions when enabled.
Test: builds, boots, no AMS lock inversions detected
Bug: 35410906
Change-Id: I473d634d23c08538029412a1254bf4f92b96fb84
diff --git a/services/core/java/com/android/server/pm/UserManagerService.java b/services/core/java/com/android/server/pm/UserManagerService.java
index 627fa54..b9fcf4e 100644
--- a/services/core/java/com/android/server/pm/UserManagerService.java
+++ b/services/core/java/com/android/server/pm/UserManagerService.java
@@ -94,6 +94,7 @@
import com.android.internal.util.XmlUtils;
import com.android.internal.widget.LockPatternUtils;
import com.android.server.LocalServices;
+import com.android.server.LockGuard;
import com.android.server.SystemService;
import com.android.server.am.UserState;
import com.android.server.storage.DeviceStorageMonitorInternal;
@@ -227,7 +228,7 @@
private final Object mPackagesLock;
private final UserDataPreparer mUserDataPreparer;
// Short-term lock for internal state, when interaction/sync with PM is not required
- private final Object mUsersLock = new Object();
+ private final Object mUsersLock = LockGuard.installNewLock(LockGuard.INDEX_USER);
private final Object mRestrictionsLock = new Object();
private final Handler mHandler;