Keep app in high memory adjust if moving from TOP to FGS

If an app was in the TOP state and immediately moved
to a foreground service state, then try harder to keep it
in memory for another 20 seconds before releasing the
memory to bound foreground services. Using an oom_adj value
of 50 which is between "fore" and "vis". So BFGS apps might
get killed ("vis") before this recently FGS'ed app. That
way any app that has a lot of state in memory that it needs
to persist before getting killed has a chance to do so.

Also bind NotificationListeners with a special bind flag
to rank them below FGS (perceptible adj) so that they
can be killed before any other foreground services or
bound services get killed.

Bug: 110969183
Test: Manual for now. Take a bunch of portrait
      pictures and hit home, while being under memory
      pressure with a bunch of notification listeners.
Change-Id: Ie8934c2331afe6450c582b209869aeca7272f58a

7 files changed, 77 insertions, 3 deletions

diff --git a/core/java/android/content/Context.java b/core/java/android/content/Context.java
index ddd12a546650..35deb0886c3d 100644
--- a/core/java/android/content/Context.java
+++ b/core/java/android/content/Context.java
@@ -327,6 +327,15 @@ public abstract class Context {
     public static final int BIND_ADJUST_WITH_ACTIVITY = 0x0080;
 
     /**
+     * Flag for {@link #bindService}: If binding from something better than perceptible,
+     * still set the adjust below perceptible. This would be used for bound services that can
+     * afford to be evicted when under extreme memory pressure, but should be restarted as soon
+     * as possible.
+     * @hide
+     */
+    public static final int BIND_ADJUST_BELOW_PERCEPTIBLE = 0x0100;
+
+    /**
      * @hide Flag for {@link #bindService}: allows binding to a service provided
      * by an instant app. Note that the caller may not have access to the instant
      * app providing the service which is a violation of the instant app sandbox.
diff --git a/services/core/java/com/android/server/am/ActivityManagerConstants.java b/services/core/java/com/android/server/am/ActivityManagerConstants.java
index 2c8f2fcd8af1..3a0289cbfd63 100644
--- a/services/core/java/com/android/server/am/ActivityManagerConstants.java
+++ b/services/core/java/com/android/server/am/ActivityManagerConstants.java
@@ -68,6 +68,7 @@ final class ActivityManagerConstants extends ContentObserver {
     static final String KEY_BOUND_SERVICE_CRASH_MAX_RETRY = "service_crash_max_retry";
     static final String KEY_PROCESS_START_ASYNC = "process_start_async";
     static final String KEY_MEMORY_INFO_THROTTLE_TIME = "memory_info_throttle_time";
+    static final String KEY_TOP_TO_FGS_GRACE_DURATION = "top_to_fgs_grace_duration";
 
     private static final int DEFAULT_MAX_CACHED_PROCESSES = 32;
     private static final long DEFAULT_BACKGROUND_SETTLE_TIME = 60*1000;
@@ -97,6 +98,7 @@ final class ActivityManagerConstants extends ContentObserver {
     private static final int DEFAULT_BOUND_SERVICE_CRASH_MAX_RETRY = 16;
     private static final boolean DEFAULT_PROCESS_START_ASYNC = true;
     private static final long DEFAULT_MEMORY_INFO_THROTTLE_TIME = 5*60*1000;
+    private static final long DEFAULT_TOP_TO_FGS_GRACE_DURATION = 15 * 1000;
 
     // Maximum number of cached processes we will allow.
     public int MAX_CACHED_PROCESSES = DEFAULT_MAX_CACHED_PROCESSES;
@@ -212,6 +214,10 @@ final class ActivityManagerConstants extends ContentObserver {
     // throttle requests from apps.
     public long MEMORY_INFO_THROTTLE_TIME = DEFAULT_MEMORY_INFO_THROTTLE_TIME;
 
+    // Allow app just moving from TOP to FOREGROUND_SERVICE to stay in a higher adj value for
+    // this long.
+    public long TOP_TO_FGS_GRACE_DURATION = DEFAULT_TOP_TO_FGS_GRACE_DURATION;
+
     // Indicates whether the activity starts logging is enabled.
     // Controlled by Settings.Global.ACTIVITY_STARTS_LOGGING_ENABLED
     boolean mFlagActivityStartsLoggingEnabled;
@@ -355,6 +361,8 @@ final class ActivityManagerConstants extends ContentObserver {
                     DEFAULT_PROCESS_START_ASYNC);
             MEMORY_INFO_THROTTLE_TIME = mParser.getLong(KEY_MEMORY_INFO_THROTTLE_TIME,
                     DEFAULT_MEMORY_INFO_THROTTLE_TIME);
+            TOP_TO_FGS_GRACE_DURATION = mParser.getDurationMillis(KEY_TOP_TO_FGS_GRACE_DURATION,
+                    DEFAULT_TOP_TO_FGS_GRACE_DURATION);
 
             updateMaxCachedProcesses();
         }
@@ -438,6 +446,8 @@ final class ActivityManagerConstants extends ContentObserver {
         pw.println(FLAG_PROCESS_START_ASYNC);
         pw.print("  "); pw.print(KEY_MEMORY_INFO_THROTTLE_TIME); pw.print("=");
         pw.println(MEMORY_INFO_THROTTLE_TIME);
+        pw.print("  "); pw.print(KEY_TOP_TO_FGS_GRACE_DURATION); pw.print("=");
+        pw.println(TOP_TO_FGS_GRACE_DURATION);
 
         pw.println();
         if (mOverrideMaxCachedProcesses >= 0) {
diff --git a/services/core/java/com/android/server/am/ActivityManagerService.java b/services/core/java/com/android/server/am/ActivityManagerService.java
index 2ee598fee535..104524d6b18f 100644
--- a/services/core/java/com/android/server/am/ActivityManagerService.java
+++ b/services/core/java/com/android/server/am/ActivityManagerService.java
@@ -17776,6 +17776,19 @@ public class ActivityManagerService extends IActivityManager.Stub
             }
         }
 
+        // If the app was recently in the foreground and moved to a foreground service status,
+        // allow it to get a higher rank in memory for some time, compared to other foreground
+        // services so that it can finish performing any persistence/processing of in-memory state.
+        if (app.hasForegroundServices() && adj > ProcessList.PERCEPTIBLE_RECENT_FOREGROUND_APP_ADJ
+                && (app.lastTopTime + mConstants.TOP_TO_FGS_GRACE_DURATION > now
+                    || app.setProcState <= ActivityManager.PROCESS_STATE_TOP)) {
+            adj = ProcessList.PERCEPTIBLE_RECENT_FOREGROUND_APP_ADJ;
+            app.adjType = "fg-service-act";
+            if (DEBUG_OOM_ADJ_REASON || logUid == appUid) {
+                reportOomAdjMessageLocked(TAG_OOM_ADJ, "Raise to recent fg: " + app);
+            }
+        }
+
         if (adj > ProcessList.PERCEPTIBLE_APP_ADJ
                 || procState > ActivityManager.PROCESS_STATE_TRANSIENT_BACKGROUND) {
             if (app.forcingToImportant != null) {
@@ -18043,6 +18056,10 @@ public class ActivityManagerService extends IActivityManager.Stub
                                         cr.trackProcState(procState, mAdjSeq, now);
                                         trackedProcState = true;
                                     }
+                                } else if ((cr.flags & Context.BIND_ADJUST_BELOW_PERCEPTIBLE) != 0
+                                        && clientAdj < ProcessList.PERCEPTIBLE_APP_ADJ
+                                        && adj > ProcessList.PERCEPTIBLE_APP_ADJ + 1) {
+                                    newAdj = ProcessList.PERCEPTIBLE_APP_ADJ + 1;
                                 } else if ((cr.flags&Context.BIND_NOT_VISIBLE) != 0
                                         && clientAdj < ProcessList.PERCEPTIBLE_APP_ADJ
                                         && adj > ProcessList.PERCEPTIBLE_APP_ADJ) {
@@ -19042,6 +19059,8 @@ public class ActivityManagerService extends IActivityManager.Stub
             // Must be called before updating setProcState
             maybeUpdateUsageStatsLocked(app, nowElapsed);
 
+            maybeUpdateLastTopTime(app, now);
+
             app.setProcState = app.curProcState;
             if (app.setProcState >= ActivityManager.PROCESS_STATE_HOME) {
                 app.notCachedSinceIdle = false;
@@ -19266,6 +19285,13 @@ public class ActivityManagerService extends IActivityManager.Stub
         }
     }
 
+    private void maybeUpdateLastTopTime(ProcessRecord app, long nowUptime) {
+        if (app.setProcState <= ActivityManager.PROCESS_STATE_TOP
+                && app.curProcState > ActivityManager.PROCESS_STATE_TOP) {
+            app.lastTopTime = nowUptime;
+        }
+    }
+
     private final void setProcessTrackerStateLocked(ProcessRecord proc, int memFactor, long now) {
         if (proc.thread != null && proc.baseProcessTracker != null) {
             proc.baseProcessTracker.setState(
diff --git a/services/core/java/com/android/server/am/ProcessList.java b/services/core/java/com/android/server/am/ProcessList.java
index 784d62e51966..3ac7885eba37 100644
--- a/services/core/java/com/android/server/am/ProcessList.java
+++ b/services/core/java/com/android/server/am/ProcessList.java
@@ -104,6 +104,11 @@ public final class ProcessList {
     static final int VISIBLE_APP_ADJ = 100;
     static final int VISIBLE_APP_LAYER_MAX = PERCEPTIBLE_APP_ADJ - VISIBLE_APP_ADJ - 1;
 
+    // This is a process that was recently TOP and moved to FGS. Continue to treat it almost
+    // like a foreground app for a while.
+    // @see TOP_TO_FGS_GRACE_PERIOD
+    static final int PERCEPTIBLE_RECENT_FOREGROUND_APP_ADJ = 50;
+
     // This is the process running the current foreground app.  We'd really
     // rather not kill it!
     static final int FOREGROUND_APP_ADJ = 0;
diff --git a/services/core/java/com/android/server/am/ProcessRecord.java b/services/core/java/com/android/server/am/ProcessRecord.java
index 144f18b219dc..d3dc0f34cbf1 100644
--- a/services/core/java/com/android/server/am/ProcessRecord.java
+++ b/services/core/java/com/android/server/am/ProcessRecord.java
@@ -198,6 +198,7 @@ final class ProcessRecord implements WindowProcessListener {
     long lastRequestedGc;       // When we last asked the app to do a gc
     long lastLowMemory;         // When we last told the app that memory is low
     long lastProviderTime;      // The last time someone else was using a provider in this process.
+    long lastTopTime;           // The last time the process was in the TOP state or greater.
     boolean reportLowMemory;    // Set to true when waiting to report low mem
     boolean empty;              // Is this an empty background process?
     boolean cached;             // Is this a cached process?
@@ -415,6 +416,11 @@ final class ProcessRecord implements WindowProcessListener {
             TimeUtils.formatDuration(lastProviderTime, nowUptime, pw);
             pw.println();
         }
+        if (lastTopTime > 0) {
+            pw.print(prefix); pw.print("lastTopTime=");
+            TimeUtils.formatDuration(lastTopTime, nowUptime, pw);
+            pw.println();
+        }
         if (hasStartedServices) {
             pw.print(prefix); pw.print("hasStartedServices="); pw.println(hasStartedServices);
         }
diff --git a/services/core/java/com/android/server/notification/ManagedServices.java b/services/core/java/com/android/server/notification/ManagedServices.java
index 340ae0ad637a..fc51fb090d83 100644
--- a/services/core/java/com/android/server/notification/ManagedServices.java
+++ b/services/core/java/com/android/server/notification/ManagedServices.java
@@ -178,6 +178,10 @@ abstract public class ManagedServices {
         }
     }
 
+    protected int getBindFlags() {
+        return BIND_AUTO_CREATE | BIND_FOREGROUND_SERVICE | BIND_ALLOW_WHITELIST_MANAGEMENT;
+    }
+
     protected void onServiceRemovedLocked(ManagedServiceInfo removed) { }
 
     private ManagedServiceInfo newServiceInfo(IInterface service,
@@ -1063,9 +1067,9 @@ abstract public class ManagedServices {
                 }
             };
             if (!mContext.bindServiceAsUser(intent,
-                serviceConnection,
-                BIND_AUTO_CREATE | BIND_FOREGROUND_SERVICE | BIND_ALLOW_WHITELIST_MANAGEMENT,
-                new UserHandle(userid))) {
+                    serviceConnection,
+                    getBindFlags(),
+                    new UserHandle(userid))) {
                 mServicesBound.remove(servicesBindingTag);
                 Slog.w(TAG, "Unable to bind " + getCaption() + " service: " + intent);
                 return;
diff --git a/services/core/java/com/android/server/notification/NotificationManagerService.java b/services/core/java/com/android/server/notification/NotificationManagerService.java
index ce71dd2ec9ad..608e403ff511 100644
--- a/services/core/java/com/android/server/notification/NotificationManagerService.java
+++ b/services/core/java/com/android/server/notification/NotificationManagerService.java
@@ -33,6 +33,10 @@ import static android.app.NotificationManager.Policy.SUPPRESSED_EFFECT_PEEK;
 import static android.app.NotificationManager.Policy.SUPPRESSED_EFFECT_SCREEN_OFF;
 import static android.app.NotificationManager.Policy.SUPPRESSED_EFFECT_SCREEN_ON;
 import static android.app.NotificationManager.Policy.SUPPRESSED_EFFECT_STATUS_BAR;
+import static android.content.Context.BIND_ADJUST_BELOW_PERCEPTIBLE;
+import static android.content.Context.BIND_ALLOW_WHITELIST_MANAGEMENT;
+import static android.content.Context.BIND_AUTO_CREATE;
+import static android.content.Context.BIND_FOREGROUND_SERVICE;
 import static android.content.pm.PackageManager.FEATURE_LEANBACK;
 import static android.content.pm.PackageManager.FEATURE_TELEVISION;
 import static android.content.pm.PackageManager.PERMISSION_GRANTED;
@@ -6689,6 +6693,16 @@ public class NotificationManagerService extends SystemService {
         }
 
         @Override
+        protected int getBindFlags() {
+            // Most of the same flags as the base, but also add BIND_ADJUST_BELOW_PERCEPTIBLE
+            // because too many 3P apps could be kept in memory as notification listeners and
+            // cause extreme memory pressure.
+            // TODO: Change the binding lifecycle of NotificationListeners to avoid this situation.
+            return BIND_AUTO_CREATE | BIND_FOREGROUND_SERVICE
+                    | BIND_ADJUST_BELOW_PERCEPTIBLE | BIND_ALLOW_WHITELIST_MANAGEMENT;
+        }
+
+        @Override
         protected Config getConfig() {
             Config c = new Config();
             c.caption = "notification listener";