Merge "Refactor/unify rate-limiting code in NotificationManager" into main (91e75541) · Commits · e / os / android_frameworks_base

core/java/android/app/NotificationManager.java

+58 −17

Original line number	Diff line number	Diff line
		@@ -68,6 +68,7 @@ import android.service.notification.StatusBarNotification;
		import android.service.notification.ZenDeviceEffects;
		import android.service.notification.ZenModeConfig;
		import android.service.notification.ZenPolicy;
		import android.text.TextUtils;
		import android.util.Log;
		import android.util.LruCache;
		import android.util.Slog;
		@@ -77,6 +78,8 @@ import com.android.internal.annotations.VisibleForTesting;

		import java.lang.annotation.Retention;
		import java.lang.annotation.RetentionPolicy;
		import java.time.Duration;
		import java.time.Instant;
		import java.time.InstantSource;
		import java.util.ArrayList;
		import java.util.Arrays;
		@@ -661,8 +664,10 @@ public class NotificationManager {
		mCallNotificationEventCallbacks = new HashMap<>();

		private final InstantSource mClock;
		private final RateEstimator mUpdateRateEstimator = new RateEstimator();
		private final RateEstimator mUnnecessaryCancelRateEstimator = new RateEstimator();
		private final RateLimiter mUpdateRateLimiter = new RateLimiter("notify (update)",
		MAX_NOTIFICATION_UPDATE_RATE);
		private final RateLimiter mUnnecessaryCancelRateLimiter = new RateLimiter("cancel (dupe)",
		MAX_NOTIFICATION_UNNECESSARY_CANCEL_RATE);
		// Value is KNOWN_STATUS_ENQUEUED/_CANCELLED
		private final LruCache<NotificationKey, Integer> mKnownNotifications = new LruCache<>(100);
		private final Object mThrottleLock = new Object();
		@@ -820,21 +825,16 @@ public class NotificationManager {

		if (Flags.nmBinderPerfThrottleNotify()) {
		NotificationKey key = new NotificationKey(user, pkg, tag, id);
		long now = mClock.millis();
		synchronized (mThrottleLock) {
		Integer status = mKnownNotifications.get(key);
		if (status != null && status == KNOWN_STATUS_ENQUEUED
		&& !notification.hasCompletedProgress()) {
		float updateRate = mUpdateRateEstimator.getRate(now);
		if (updateRate > MAX_NOTIFICATION_UPDATE_RATE) {
		Slog.w(TAG, "Shedding update of " + key
		+ ", notification update maximum rate exceeded (" + updateRate
		+ ")");
		if (mUpdateRateLimiter.eventExceedsRate()) {
		mUpdateRateLimiter.recordRejected(key);
		return true;
		}
		mUpdateRateEstimator.update(now);
		mUpdateRateLimiter.recordAccepted();
		}

		mKnownNotifications.put(key, KNOWN_STATUS_ENQUEUED);
		}
		}
		@@ -845,6 +845,51 @@ public class NotificationManager {
		private record NotificationKey(@NonNull UserHandle user, @NonNull String pkg,
		@Nullable String tag, int id) { }

		/** Helper class to rate-limit Binder calls. */
		private class RateLimiter {

		private static final Duration RATE_LIMITER_LOG_INTERVAL = Duration.ofSeconds(5);

		private final RateEstimator mInputRateEstimator;
		private final RateEstimator mOutputRateEstimator;
		private final String mName;
		private final float mLimitRate;

		private Instant mLogSilencedUntil;

		private RateLimiter(String name, float limitRate) {
		mInputRateEstimator = new RateEstimator();
		mOutputRateEstimator = new RateEstimator();
		mName = name;
		mLimitRate = limitRate;
		}

		boolean eventExceedsRate() {
		long nowMillis = mClock.millis();
		mInputRateEstimator.update(nowMillis);
		return mOutputRateEstimator.getRate(nowMillis) > mLimitRate;
		}

		void recordAccepted() {
		mOutputRateEstimator.update(mClock.millis());
		}

		void recordRejected(NotificationKey key) {
		Instant now = mClock.instant();
		if (mLogSilencedUntil != null && now.isBefore(mLogSilencedUntil)) {
		return;
		}

		long nowMillis = now.toEpochMilli();
		Slog.w(TAG, TextUtils.formatSimple(
		"Shedding %s of %s, rate limit (%s) exceeded: input %s, output would be %s",
		mName, key, mLimitRate, mInputRateEstimator.getRate(nowMillis),
		mOutputRateEstimator.getRate(nowMillis)));

		mLogSilencedUntil = now.plus(RATE_LIMITER_LOG_INTERVAL);
		}
		}

		private Notification fixNotification(Notification notification) {
		String pkg = mContext.getPackageName();
		// Fix the notification as best we can.
		@@ -967,18 +1012,14 @@ public class NotificationManager {
		private boolean discardCancel(UserHandle user, String pkg, @Nullable String tag, int id) {
		if (Flags.nmBinderPerfThrottleNotify()) {
		NotificationKey key = new NotificationKey(user, pkg, tag, id);
		long now = mClock.millis();
		synchronized (mThrottleLock) {
		Integer status = mKnownNotifications.get(key);
		if (status != null && status == KNOWN_STATUS_CANCELLED) {
		float cancelRate = mUnnecessaryCancelRateEstimator.getRate(now);
		if (cancelRate > MAX_NOTIFICATION_UNNECESSARY_CANCEL_RATE) {
		Slog.w(TAG, "Shedding cancel of " + key
		+ ", presumably unnecessary and maximum rate exceeded ("
		+ cancelRate + ")");
		if (mUnnecessaryCancelRateLimiter.eventExceedsRate()) {
		mUnnecessaryCancelRateLimiter.recordRejected(key);
		return true;
		}
		mUnnecessaryCancelRateEstimator.update(now);
		mUnnecessaryCancelRateLimiter.recordAccepted();
		}
		mKnownNotifications.put(key, KNOWN_STATUS_CANCELLED);
		}