Make tiered cached adj UI tier size configurable

This change makes the UI tier size configurable through overlays. By
default, the UI tier can contain 10 processes.

Test: - atest MockingOomAdjusterTests
      - device_config put activity_manager
        tiered_cached_adj_ui_tier_size, followed by dumpsys activity
        settings to check that the size was updated
      - build with a device-specific config to check that the size is
        non-default
Bug: 373863708
Bug: 374541382
Flag: com.android.server.am.oomadjuster_cached_app_tiers
Change-Id: Iadca88f79c232a8fb5f6a5a69807a30029bb8a8c

5 files changed, 54 insertions, 22 deletions

diff --git a/core/res/res/values/config.xml b/core/res/res/values/config.xml
index 41981715a855..454db21ee3ae 100644
--- a/core/res/res/values/config.xml
+++ b/core/res/res/values/config.xml
@@ -7054,6 +7054,9 @@
          RSS is being collected instead. -->
     <item name="config_am_pssToRssThresholdModifier" format="float" type="dimen">1.5</item>
 
+    <!-- The size of the UI tier if cached app oom_adj_score tiers are enabled. -->
+    <integer name="config_am_tieredCachedAdjUiTierSize">10</integer>
+
     <!-- Whether unlocking and waking a device are sequenced -->
     <bool name="config_orderUnlockAndWake">false</bool>
 
diff --git a/core/res/res/values/symbols.xml b/core/res/res/values/symbols.xml
index b4249557b4c9..e784e7521a9e 100644
--- a/core/res/res/values/symbols.xml
+++ b/core/res/res/values/symbols.xml
@@ -5498,6 +5498,9 @@
   <java-symbol type="bool" name="config_am_disablePssProfiling" />
   <java-symbol type="dimen" name="config_am_pssToRssThresholdModifier" />
 
+  <!-- For OomAdjuster cached app tiers configurability -->
+  <java-symbol type="integer" name="config_am_tieredCachedAdjUiTierSize" />
+
   <java-symbol type="raw" name="default_ringtone_vibration_effect" />
 
   <!-- For activity embedding divider -->
diff --git a/services/core/java/com/android/server/am/ActivityManagerConstants.java b/services/core/java/com/android/server/am/ActivityManagerConstants.java
index 65a2c187f1c8..4944cafeb83d 100644
--- a/services/core/java/com/android/server/am/ActivityManagerConstants.java
+++ b/services/core/java/com/android/server/am/ActivityManagerConstants.java
@@ -163,6 +163,7 @@ final class ActivityManagerConstants extends ContentObserver {
 
     static final String KEY_USE_TIERED_CACHED_ADJ = "use_tiered_cached_adj";
     static final String KEY_TIERED_CACHED_ADJ_DECAY_TIME = "tiered_cached_adj_decay_time";
+    static final String KEY_TIERED_CACHED_ADJ_UI_TIER_SIZE = "tiered_cached_adj_ui_tier_size";
 
     /**
      * Whether or not to enable the new oom adjuster implementation.
@@ -248,6 +249,8 @@ final class ActivityManagerConstants extends ContentObserver {
 
     private static final boolean DEFAULT_USE_TIERED_CACHED_ADJ = Flags.oomadjusterCachedAppTiers();
     private static final long DEFAULT_TIERED_CACHED_ADJ_DECAY_TIME = 60 * 1000;
+    private static final int TIERED_CACHED_ADJ_MAX_UI_TIER_SIZE = 50;
+    private final int mDefaultTieredCachedAdjUiTierSize;
 
     /**
      * The default value to {@link #KEY_ENABLE_NEW_OOMADJ}.
@@ -1154,6 +1157,9 @@ final class ActivityManagerConstants extends ContentObserver {
     /** @see #KEY_TIERED_CACHED_ADJ_DECAY_TIME */
     public long TIERED_CACHED_ADJ_DECAY_TIME = DEFAULT_TIERED_CACHED_ADJ_DECAY_TIME;
 
+    /** @see #KEY_TIERED_CACHED_ADJ_UI_TIER_SIZE */
+    public int TIERED_CACHED_ADJ_UI_TIER_SIZE;
+
     /** @see #KEY_ENABLE_NEW_OOMADJ */
     public boolean ENABLE_NEW_OOMADJ = DEFAULT_ENABLE_NEW_OOM_ADJ;
 
@@ -1363,6 +1369,7 @@ final class ActivityManagerConstants extends ContentObserver {
                                 break;
                             case KEY_USE_TIERED_CACHED_ADJ:
                             case KEY_TIERED_CACHED_ADJ_DECAY_TIME:
+                            case KEY_TIERED_CACHED_ADJ_UI_TIER_SIZE:
                                 updateUseTieredCachedAdj();
                                 break;
                             case KEY_DISABLE_APP_PROFILER_PSS_PROFILING:
@@ -1466,6 +1473,11 @@ final class ActivityManagerConstants extends ContentObserver {
         mDefaultPssToRssThresholdModifier = context.getResources().getFloat(
                 com.android.internal.R.dimen.config_am_pssToRssThresholdModifier);
         PSS_TO_RSS_THRESHOLD_MODIFIER = mDefaultPssToRssThresholdModifier;
+
+        mDefaultTieredCachedAdjUiTierSize = context.getResources().getInteger(
+                com.android.internal.R.integer.config_am_tieredCachedAdjUiTierSize);
+        TIERED_CACHED_ADJ_UI_TIER_SIZE = Math.min(
+                mDefaultTieredCachedAdjUiTierSize, TIERED_CACHED_ADJ_MAX_UI_TIER_SIZE);
     }
 
     public void start(ContentResolver resolver) {
@@ -2255,6 +2267,12 @@ final class ActivityManagerConstants extends ContentObserver {
             DeviceConfig.NAMESPACE_ACTIVITY_MANAGER,
             KEY_TIERED_CACHED_ADJ_DECAY_TIME,
             DEFAULT_TIERED_CACHED_ADJ_DECAY_TIME);
+        TIERED_CACHED_ADJ_UI_TIER_SIZE = Math.min(
+                DeviceConfig.getInt(
+                    DeviceConfig.NAMESPACE_ACTIVITY_MANAGER,
+                    KEY_TIERED_CACHED_ADJ_UI_TIER_SIZE,
+                    mDefaultTieredCachedAdjUiTierSize),
+                TIERED_CACHED_ADJ_MAX_UI_TIER_SIZE);
     }
 
     private void updateEnableNewOomAdj() {
@@ -2510,6 +2528,8 @@ final class ActivityManagerConstants extends ContentObserver {
         pw.print("="); pw.println(USE_TIERED_CACHED_ADJ);
         pw.print("  "); pw.print(KEY_TIERED_CACHED_ADJ_DECAY_TIME);
         pw.print("="); pw.println(TIERED_CACHED_ADJ_DECAY_TIME);
+        pw.print("  "); pw.print(KEY_TIERED_CACHED_ADJ_UI_TIER_SIZE);
+        pw.print("="); pw.println(TIERED_CACHED_ADJ_UI_TIER_SIZE);
 
         pw.print("  "); pw.print(KEY_ENABLE_NEW_OOMADJ);
         pw.print("="); pw.println(ENABLE_NEW_OOMADJ);
diff --git a/services/core/java/com/android/server/am/OomAdjuster.java b/services/core/java/com/android/server/am/OomAdjuster.java
index 70517145575a..8d16eb5fc95a 100644
--- a/services/core/java/com/android/server/am/OomAdjuster.java
+++ b/services/core/java/com/android/server/am/OomAdjuster.java
@@ -1149,6 +1149,8 @@ public class OomAdjuster {
         if (mConstants.USE_TIERED_CACHED_ADJ) {
             final long now = mInjector.getUptimeMillis();
             int uiTargetAdj = 10;
+            // mConstants.TIERED_CACHED_ADJ_UI_TIER_SIZE is 10 by default, but is configurable.
+            final int uiTierMaxAdj = 10 + mConstants.TIERED_CACHED_ADJ_UI_TIER_SIZE;
             for (int i = numLru - 1; i >= 0; i--) {
                 ProcessRecord app = lruList.get(i);
                 final ProcessStateRecord state = app.mState;
@@ -1162,17 +1164,17 @@ public class OomAdjuster {
                     if (opt != null && opt.isFreezeExempt()) {
                         // BIND_WAIVE_PRIORITY and the like get oom_adj 900
                         targetAdj += 0;
-                    } else if (state.hasShownUi() && uiTargetAdj < 20) {
-                        // The most recent 10 apps that have shown UI get 910-919
+                    } else if (state.hasShownUi() && uiTargetAdj < uiTierMaxAdj) {
+                        // The most recent UI-showing apps get [910, 910 + ui tier size).
                         targetAdj += uiTargetAdj++;
                     } else if ((state.getSetAdj() >= CACHED_APP_MIN_ADJ)
                             && (state.getLastStateTime()
                                     + mConstants.TIERED_CACHED_ADJ_DECAY_TIME) < now) {
-                        // Older cached apps get 950
-                        targetAdj += 50;
+                        // Older cached apps get 940 + ui tier size (950 by default).
+                        targetAdj += 40 + mConstants.TIERED_CACHED_ADJ_UI_TIER_SIZE;
                     } else {
-                        // Newer cached apps get 920
-                        targetAdj += 20;
+                        // Newer cached apps get 910 + ui tier size (920 by default).
+                        targetAdj += 10 + mConstants.TIERED_CACHED_ADJ_UI_TIER_SIZE;
                     }
                     state.setCurRawAdj(targetAdj);
                     state.setCurAdj(psr.modifyRawOomAdj(targetAdj));
diff --git a/services/tests/mockingservicestests/src/com/android/server/am/MockingOomAdjusterTests.java b/services/tests/mockingservicestests/src/com/android/server/am/MockingOomAdjusterTests.java
index 250c2f93e70e..6ab72cd33042 100644
--- a/services/tests/mockingservicestests/src/com/android/server/am/MockingOomAdjusterTests.java
+++ b/services/tests/mockingservicestests/src/com/android/server/am/MockingOomAdjusterTests.java
@@ -167,8 +167,6 @@ public class MockingOomAdjusterTests {
     private static int sFirstCachedAdj = ProcessList.CACHED_APP_MIN_ADJ
             + ProcessList.CACHED_APP_IMPORTANCE_LEVELS;
     private static int sFirstUiCachedAdj = ProcessList.CACHED_APP_MIN_ADJ + 10;
-    private static int sFirstNonUiCachedAdj = ProcessList.CACHED_APP_MIN_ADJ + 20;
-    private static int sUiTierSize = 10;
 
     private Context mContext;
     private ProcessStateController mProcessStateController;
@@ -177,6 +175,9 @@ public class MockingOomAdjusterTests {
     private ActivityManagerService mService;
     private OomAdjusterInjector mInjector = new OomAdjusterInjector();
 
+    private int mUiTierSize;
+    private int mFirstNonUiCachedAdj;
+
     @Rule
     public final SetFlagsRule mSetFlagsRule = new SetFlagsRule();
 
@@ -247,6 +248,9 @@ public class MockingOomAdjusterTests {
         mService.mOomAdjuster.mAdjSeq = 10000;
         mService.mWakefulness = new AtomicInteger(PowerManagerInternal.WAKEFULNESS_AWAKE);
         mSetFlagsRule.enableFlags(Flags.FLAG_NEW_FGS_RESTRICTION_LOGIC);
+
+        mUiTierSize = mService.mConstants.TIERED_CACHED_ADJ_UI_TIER_SIZE;
+        mFirstNonUiCachedAdj = sFirstUiCachedAdj + mUiTierSize;
     }
 
     @SuppressWarnings("GuardedBy")
@@ -927,8 +931,8 @@ public class MockingOomAdjusterTests {
             final int mruIndex = numberOfApps - i - 1;
             int expectedAdj;
             if (mService.mConstants.USE_TIERED_CACHED_ADJ) {
-                expectedAdj = (i < numberOfApps - sUiTierSize)
-                        ? sFirstNonUiCachedAdj : sFirstUiCachedAdj + mruIndex;
+                expectedAdj = (i < numberOfApps - mUiTierSize)
+                        ? mFirstNonUiCachedAdj : sFirstUiCachedAdj + mruIndex;
             } else {
                 expectedAdj = CACHED_APP_MIN_ADJ + (mruIndex * 2 * CACHED_APP_IMPORTANCE_LEVELS);
                 if (expectedAdj > CACHED_APP_MAX_ADJ) {
@@ -1108,7 +1112,7 @@ public class MockingOomAdjusterTests {
         updateOomAdj(app);
 
         final int expectedAdj = mService.mConstants.USE_TIERED_CACHED_ADJ
-                ? sFirstNonUiCachedAdj : sFirstCachedAdj;
+                ? mFirstNonUiCachedAdj : sFirstCachedAdj;
         assertProcStates(app, PROCESS_STATE_CACHED_EMPTY, expectedAdj, SCHED_GROUP_BACKGROUND);
     }
 
@@ -1545,7 +1549,7 @@ public class MockingOomAdjusterTests {
         updateOomAdj(app);
 
         final int expectedAdj = mService.mConstants.USE_TIERED_CACHED_ADJ
-                ? sFirstNonUiCachedAdj : sFirstCachedAdj;
+                ? mFirstNonUiCachedAdj : sFirstCachedAdj;
         assertProcStates(app, PROCESS_STATE_CACHED_EMPTY, expectedAdj, SCHED_GROUP_BACKGROUND);
     }
 
@@ -1563,7 +1567,7 @@ public class MockingOomAdjusterTests {
         updateOomAdj(app, client);
 
         final int expectedAdj = mService.mConstants.USE_TIERED_CACHED_ADJ
-                ? sFirstNonUiCachedAdj : sFirstCachedAdj;
+                ? mFirstNonUiCachedAdj : sFirstCachedAdj;
         assertProcStates(app, PROCESS_STATE_CACHED_EMPTY, expectedAdj, SCHED_GROUP_BACKGROUND);
     }
 
@@ -1694,7 +1698,7 @@ public class MockingOomAdjusterTests {
         mProcessStateController.runFollowUpUpdate();
 
         final int expectedAdj = mService.mConstants.USE_TIERED_CACHED_ADJ
-                ? sFirstNonUiCachedAdj : sFirstCachedAdj;
+                ? mFirstNonUiCachedAdj : sFirstCachedAdj;
         assertProcStates(app, PROCESS_STATE_CACHED_EMPTY, expectedAdj, SCHED_GROUP_BACKGROUND,
                 "cch-empty");
         // Follow up should not have been called again.
@@ -2741,7 +2745,7 @@ public class MockingOomAdjusterTests {
         final int userOther = 1;
 
         // cachedAdj1 and cachedAdj2 will be read if USE_TIERED_CACHED_ADJ is disabled. Otherwise,
-        // sFirstUiCachedAdj and sFirstNonUiCachedAdj are used instead.
+        // sFirstUiCachedAdj and mFirstNonUiCachedAdj are used instead.
         final int cachedAdj1 = CACHED_APP_MIN_ADJ + CACHED_APP_IMPORTANCE_LEVELS;
         final int cachedAdj2 = cachedAdj1 + CACHED_APP_IMPORTANCE_LEVELS * 2;
         doReturn(userOwner).when(mService.mUserController).getCurrentUserId();
@@ -2789,7 +2793,7 @@ public class MockingOomAdjusterTests {
                 mService.mConstants.USE_TIERED_CACHED_ADJ ? sFirstUiCachedAdj : cachedAdj1,
                 SCHED_GROUP_BACKGROUND, "cch-started-ui-services", true);
         assertProcStates(app2, PROCESS_STATE_SERVICE,
-                mService.mConstants.USE_TIERED_CACHED_ADJ ? sFirstNonUiCachedAdj : cachedAdj2,
+                mService.mConstants.USE_TIERED_CACHED_ADJ ? mFirstNonUiCachedAdj : cachedAdj2,
                 SCHED_GROUP_BACKGROUND, "cch-started-services", true);
 
         app.mState.setSetProcState(PROCESS_STATE_NONEXISTENT);
@@ -2809,7 +2813,7 @@ public class MockingOomAdjusterTests {
         updateOomAdj();
 
         assertProcStates(app, PROCESS_STATE_SERVICE,
-                mService.mConstants.USE_TIERED_CACHED_ADJ ? sFirstNonUiCachedAdj : cachedAdj1,
+                mService.mConstants.USE_TIERED_CACHED_ADJ ? mFirstNonUiCachedAdj : cachedAdj1,
                 SCHED_GROUP_BACKGROUND, "cch-started-services", true);
 
         mProcessStateController.stopService(app.mServices, s);
@@ -2831,7 +2835,7 @@ public class MockingOomAdjusterTests {
         assertProcStates(app, PROCESS_STATE_SERVICE, SERVICE_ADJ, SCHED_GROUP_BACKGROUND,
                 "started-services", false);
         assertProcStates(app2, PROCESS_STATE_SERVICE,
-                mService.mConstants.USE_TIERED_CACHED_ADJ ? sFirstNonUiCachedAdj : cachedAdj1,
+                mService.mConstants.USE_TIERED_CACHED_ADJ ? mFirstNonUiCachedAdj : cachedAdj1,
                 SCHED_GROUP_BACKGROUND, "cch-started-services", true);
 
         app.mState.setSetProcState(PROCESS_STATE_NONEXISTENT);
@@ -2845,7 +2849,7 @@ public class MockingOomAdjusterTests {
         assertProcStates(app, PROCESS_STATE_SERVICE, SERVICE_ADJ, SCHED_GROUP_BACKGROUND,
                 "started-services", false);
         assertProcStates(app2, PROCESS_STATE_SERVICE,
-                mService.mConstants.USE_TIERED_CACHED_ADJ ? sFirstNonUiCachedAdj : cachedAdj1,
+                mService.mConstants.USE_TIERED_CACHED_ADJ ? mFirstNonUiCachedAdj : cachedAdj1,
                 SCHED_GROUP_BACKGROUND, "cch-started-services", true);
 
         doReturn(userOther).when(mService.mUserController).getCurrentUserId();
@@ -2853,7 +2857,7 @@ public class MockingOomAdjusterTests {
 
         updateOomAdj();
         assertProcStates(app, PROCESS_STATE_SERVICE,
-                mService.mConstants.USE_TIERED_CACHED_ADJ ? sFirstNonUiCachedAdj : cachedAdj1,
+                mService.mConstants.USE_TIERED_CACHED_ADJ ? mFirstNonUiCachedAdj : cachedAdj1,
                 SCHED_GROUP_BACKGROUND, "cch-started-services", true);
         assertProcStates(app2, PROCESS_STATE_SERVICE, SERVICE_ADJ, SCHED_GROUP_BACKGROUND,
                 "started-services", false);
@@ -3157,7 +3161,7 @@ public class MockingOomAdjusterTests {
         mProcessStateController.runFollowUpUpdate();
 
         final int expectedAdj = mService.mConstants.USE_TIERED_CACHED_ADJ
-                ? sFirstNonUiCachedAdj : sFirstCachedAdj;
+                ? mFirstNonUiCachedAdj : sFirstCachedAdj;
         assertProcStates(app, PROCESS_STATE_SERVICE, expectedAdj, SCHED_GROUP_BACKGROUND,
                 "cch-started-services");
         // Follow up should not have been called again.
@@ -3192,7 +3196,7 @@ public class MockingOomAdjusterTests {
         mProcessStateController.runFollowUpUpdate();
 
         final int expectedAdj = mService.mConstants.USE_TIERED_CACHED_ADJ
-                ? sFirstNonUiCachedAdj : sFirstCachedAdj;
+                ? mFirstNonUiCachedAdj : sFirstCachedAdj;
         assertProcStates(app1, PROCESS_STATE_CACHED_EMPTY, expectedAdj, SCHED_GROUP_BACKGROUND,
                 "cch-empty");