Wire up zram setting, system property

The experiment framework toggles the system setting, which manipulates
the system property that init reads during boot to determine whether
we should enable zram.

Test: manual
Change-Id: I4b4f1b1673a5aa5e7f721c7dec7ebe3ea7908af2

diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 009fc39..4e34240 100644 (file)
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -11221,6 +11221,15 @@ public final class Settings {
          */
         public static final String ENABLE_GNSS_RAW_MEAS_FULL_TRACKING =
                 "enable_gnss_raw_meas_full_tracking";
+
+        /**
+         * Whether we've enabled zram on this device. Takes effect on
+         * reboot. The value "1" enables zram; "0" disables it, and
+         * everything else is unspecified.
+         * @hide
+         */
+        public static final String ZRAM_ENABLED =
+                "zram_enabled";
     }
 
     /**

diff --git a/core/proto/android/providers/settings.proto b/core/proto/android/providers/settings.proto
index fb0ebed..79c2942 100644 (file)
--- a/core/proto/android/providers/settings.proto
+++ b/core/proto/android/providers/settings.proto
@@ -388,8 +388,9 @@ message GlobalSettingsProto {
     optional SettingProto enable_deletion_helper_no_threshold_toggle = 340;
     optional SettingProto notification_snooze_options = 341;
     optional SettingProto enable_gnss_raw_meas_full_tracking = 346;
+    optional SettingProto zram_enabled = 347;
 
-    // Next tag = 347;
+    // Next tag = 348;
 }
 
 message SecureSettingsProto {

diff --git a/core/tests/coretests/src/android/provider/SettingsBackupTest.java b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
index fc86500..c37ee5c 100644 (file)
--- a/core/tests/coretests/src/android/provider/SettingsBackupTest.java
+++ b/core/tests/coretests/src/android/provider/SettingsBackupTest.java
@@ -418,7 +418,8 @@ public class SettingsBackupTest {
                     Settings.Global.WTF_IS_FATAL,
                     Settings.Global.ZEN_MODE,
                     Settings.Global.ZEN_MODE_CONFIG_ETAG,
-                    Settings.Global.ZEN_MODE_RINGER_LEVEL);
+                    Settings.Global.ZEN_MODE_RINGER_LEVEL,
+                    Settings.Global.ZRAM_ENABLED);
 
     private static final Set<String> BACKUP_BLACKLISTED_SECURE_SETTINGS =
              newHashSet(

diff --git a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProtoDumpUtil.java b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProtoDumpUtil.java
index 1d3f26e..4e0c0ab 100644 (file)
--- a/packages/SettingsProvider/src/com/android/providers/settings/SettingsProtoDumpUtil.java
+++ b/packages/SettingsProvider/src/com/android/providers/settings/SettingsProtoDumpUtil.java
@@ -1119,6 +1119,9 @@ class SettingsProtoDumpUtil {
         dumpSetting(s, p,
                 Settings.Global.NOTIFICATION_SNOOZE_OPTIONS,
                 GlobalSettingsProto.NOTIFICATION_SNOOZE_OPTIONS);
+        dumpSetting(s, p,
+                    Settings.Global.ZRAM_ENABLED,
+                    GlobalSettingsProto.ZRAM_ENABLED);
     }
 
     /** Dump a single {@link SettingsState.Setting} to a proto buf */

diff --git a/services/core/java/com/android/server/StorageManagerService.java b/services/core/java/com/android/server/StorageManagerService.java
index dc2f2a5..7361e70 100644 (file)
--- a/services/core/java/com/android/server/StorageManagerService.java
+++ b/services/core/java/com/android/server/StorageManagerService.java
@@ -49,6 +49,7 @@ import android.content.pm.ProviderInfo;
 import android.content.pm.UserInfo;
 import android.content.res.Configuration;
 import android.content.res.ObbInfo;
+import android.database.ContentObserver;
 import android.net.TrafficStats;
 import android.net.Uri;
 import android.os.Binder;
@@ -170,6 +171,10 @@ class StorageManagerService extends IStorageManager.Stub
     // Static direct instance pointer for the tightly-coupled idle service to use
     static StorageManagerService sSelf = null;
 
+    /* Read during boot to decide whether to enable zram when available */
+    private static final String ZRAM_ENABLED_PROPERTY =
+        "persist.sys.zram_enabled";
+
     public static class Lifecycle extends SystemService {
         private StorageManagerService mStorageManagerService;
 
@@ -733,6 +738,41 @@ class StorageManagerService extends IStorageManager.Stub
 
         // Start scheduling nominally-daily fstrim operations
         MountServiceIdler.scheduleIdlePass(mContext);
+
+        // Toggle zram-enable system property in response to settings
+        mContext.getContentResolver().registerContentObserver(
+            Settings.Global.getUriFor(Settings.Global.ZRAM_ENABLED),
+            false /*notifyForDescendants*/,
+            new ContentObserver(null /* current thread */) {
+                @Override
+                public void onChange(boolean selfChange) {
+                    refreshZramSettings();
+                }
+            });
+        refreshZramSettings();
+    }
+
+    /**
+     * Update the zram_enabled system property (which init reads to
+     * decide whether to enable zram) to reflect the zram_enabled
+     * preference (which we can change for experimentation purposes).
+     */
+    private void refreshZramSettings() {
+        String propertyValue = SystemProperties.get(ZRAM_ENABLED_PROPERTY);
+        if ("".equals(propertyValue)) {
+            return;  // System doesn't have zram toggling support
+        }
+        String desiredPropertyValue =
+            Settings.Global.getInt(mContext.getContentResolver(),
+                                   Settings.Global.ZRAM_ENABLED,
+                                   1) != 0
+            ? "1" : "0";
+        if (!desiredPropertyValue.equals(propertyValue)) {
+            // Avoid redundant disk writes by setting only if we're
+            // changing the property value. There's no race: we're the
+            // sole writer.
+            SystemProperties.set(ZRAM_ENABLED_PROPERTY, desiredPropertyValue);
+        }
     }
 
     /**