vldpyatkov commented on code in PR #6370: URL: https://github.com/apache/ignite-3/pull/6370#discussion_r2262510169
########## modules/network/src/main/java/org/apache/ignite/internal/network/handshake/HandshakeEventLoopSwitcher.java: ########## @@ -0,0 +1,206 @@ +/* + * Licensed to the Apache Software Foundation (ASF) under one or more + * contributor license agreements. See the NOTICE file distributed with + * this work for additional information regarding copyright ownership. + * The ASF licenses this file to You under the Apache License, Version 2.0 + * (the "License"); you may not use this file except in compliance with + * the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +package org.apache.ignite.internal.network.handshake; + +import static org.apache.ignite.internal.util.CompletableFutures.nullCompletedFuture; + +import io.netty.channel.Channel; +import io.netty.channel.ChannelId; +import io.netty.channel.EventLoop; +import java.util.HashMap; +import java.util.HashSet; +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.concurrent.CompletableFuture; +import org.apache.ignite.internal.logger.IgniteLogger; +import org.apache.ignite.internal.logger.Loggers; +import org.apache.ignite.internal.network.netty.ChannelKey; +import org.apache.ignite.network.ClusterNode; + +/** + * A class responsible for managing the assignment of Netty channels to event loops + * and switching channels between event loops when necessary. + */ +public class HandshakeEventLoopSwitcher { + private static final IgniteLogger LOG = Loggers.forClass(HandshakeEventLoopSwitcher.class); + + /** List of available event loops. */ + private final List<EventLoop> executors; + + /** Map to track the number of channels assigned to each event loop. */ + private final Map<Integer, Set<ChannelId>> activeChannelMap; + + /** + * Map to track channel reservations for specific communication connections. + * The map prevents applying different event loops for the same chenell key. + */ + private final Map<ChannelKey, Integer> channelReservationMap; + + /** + * Constructs a new instance of HandshakeEventLoopSwitcher. + * + * @param eventLoops The list of event loops to manage. + */ + public HandshakeEventLoopSwitcher(List<EventLoop> eventLoops) { + this.executors = eventLoops; + this.activeChannelMap = new HashMap<>(eventLoops.size()); + this.channelReservationMap = new HashMap<>(); + } + + /** + * Switches the event loop of a given channel if needed. + * + * @param channel The channel to potentially switch to a different event loop. + * @param afterSwitching A callback to execute after the switching operation. + * @return A CompletableFuture that completes when the event loop is switched. + */ + public CompletableFuture<Void> switchEventLoopIfNeeded(Channel channel, Runnable afterSwitching) { + return switchEventLoopIfNeeded(channel, afterSwitching, null); + } + + /** + * Switches the event loop of a given channel if needed. + * + * @param channel The channel to potentially switch to a different event loop. + * @param afterSwitching A callback to execute after the switching operation. + * @param channelKey The unique key identifying the channel. + * @return A CompletableFuture that completes when the event loop is switched. + */ + public CompletableFuture<Void> switchEventLoopIfNeeded(Channel channel, Runnable afterSwitching, ChannelKey channelKey) { + ChannelId channelId = channel.id(); + + EventLoop targetEventLoop = eventLoopForKey(channelId, channelKey); + + if (targetEventLoop != channel.eventLoop()) { + CompletableFuture<Void> fut = new CompletableFuture<>(); + + channel.deregister().addListener(deregistrationFuture -> { + if (!deregistrationFuture.isSuccess()) { + LOG.error("Cannot deregister a channel from an event loop", deregistrationFuture.cause()); + + fut.completeExceptionally(deregistrationFuture.cause()); + + channel.close(); + + return; + } + + targetEventLoop.register(channel).addListener(registrationFuture -> { + if (!registrationFuture.isSuccess()) { + LOG.error("Cannot register a channel with an event loop", registrationFuture.cause()); + + fut.completeExceptionally(deregistrationFuture.cause()); + + channel.close(); + + return; + } + + channel.closeFuture().addListener(future -> { + channelUnregistered(channelId); + }); + + + fut.complete(null); + + afterSwitching.run(); + }); + }); + + return fut; + } + + afterSwitching.run(); + + return nullCompletedFuture(); + } + + + /** + * Determines the appropriate event loop for a given channel key. + * + * @param channelId The ID of the channel. + * @param channelKey The unique key identifying the channel. + * @return The selected event loop for the channel. + */ + private synchronized EventLoop eventLoopForKey(ChannelId channelId, ChannelKey channelKey) { + if (channelKey != null) { + Integer idx = channelReservationMap.get(channelKey); + + if (idx != null) { + return executors.get(idx); + } + } + + int minCnt = Integer.MAX_VALUE; + int index = 0; + + for (int i = 0; i < executors.size(); i++) { + Set<ChannelId> channelIds = activeChannelMap.getOrDefault(i, Set.of()); + + if (channelIds.contains(channelId)) { + return executors.get(index); Review Comment: Here can be a race where the assertion could fire, do you think? -- This is an automated message from the Apache Git Service. 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