adoroszlai commented on code in PR #11726: URL: https://github.com/apache/ozone/pull/11726#discussion_r4368553587
########## hadoop-hdds/client/src/main/java/org/apache/hadoop/hdds/scm/NettyWarmUp.java: ########## @@ -0,0 +1,75 @@ +/* + * 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.hadoop.hdds.scm; + +import com.google.common.annotations.VisibleForTesting; +import java.util.concurrent.atomic.AtomicBoolean; +import org.apache.ratis.thirdparty.io.netty.buffer.PooledByteBufAllocator; +import org.apache.ratis.thirdparty.io.netty.handler.ssl.OpenSsl; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +/** + * Initializes Netty, and for TLS netty-tcnative (BoringSSL), on a background thread, so that a client's first + * datanode connection finds them ready instead of initializing them itself (about 0.1 s in a cold JVM). + */ +final class NettyWarmUp { + private static final Logger LOG = LoggerFactory.getLogger(NettyWarmUp.class); + private static final AtomicBoolean STARTED = new AtomicBoolean(); + + private NettyWarmUp() { + } + + /** + * Starts the warm-up, at most once per JVM. + * + * @param tls whether to also load and initialize netty-tcnative + * @return the warm-up thread, or null if the warm-up was started before + */ + static Thread start(boolean tls) { + if (!STARTED.compareAndSet(false, true)) { + return null; + } + final Thread thread = new Thread(() -> warmUp(tls), "ozone-client-netty-warm-up"); + thread.setDaemon(true); + thread.start(); + return thread; + } + + static void warmUp(boolean tls) { + try { + PooledByteBufAllocator.DEFAULT.directBuffer(1).release(); + if (tls) { + OpenSsl.isAvailable(); + } + } catch (Throwable t) { + // the first connection initializes whatever is missing, as without the warm-up + LOG.debug("Netty warm-up failed", t); + } + } + + @VisibleForTesting + static boolean isStarted() { + return STARTED.get(); + } + + @VisibleForTesting + static void reset() { + STARTED.set(false); + } Review Comment: nit: please avoid `@VisibleForTesting` - `isStarted` is safe, no need to mark it - `reset` exists is only for testing, rename to `resetForTesting` -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
