ce241bd11e
Motivation:
b215794de3 recently introduced a change in behavior where writeSpinCount provided a limit for how many write operations were attempted per flush operation. However when the write quantum was meet the selector write flag was not cleared, and the channel unsafe flush0 method has an optimization which prematurely exits if the write flag is set. This may lead to no write progress being made under the following scenario:
- flush is called, but the socket can't accept all data, we set the write flag
- the selector wakes us up because the socket is writable, we write data and use the writeSpinCount quantum
- we then schedule a flush() on the EventLoop to execute later, however it the flush0 optimization prematurely exits because the write flag is still set
In this scenario the socket is still writable so the EventLoop may never notify us that the socket is writable, and therefore we may never attempt to flush data to the OS.
Modifications:
- When the writeSpinCount quantum is exceeded we should clear the selector write flag
Result:
Fixes https://github.com/netty/netty/issues/7729
40 lines
1.6 KiB
Java
40 lines
1.6 KiB
Java
/*
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* Copyright 2018 The Netty Project
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*
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* The Netty Project licenses this file to you under the Apache License,
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* version 2.0 (the "License"); you may not use this file except in compliance
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* with the License. You may obtain a copy of the License at:
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*/
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package io.netty.channel.epoll;
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import io.netty.bootstrap.Bootstrap;
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import io.netty.bootstrap.ServerBootstrap;
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import io.netty.buffer.ByteBufAllocator;
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import io.netty.testsuite.transport.TestsuitePermutation;
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import io.netty.testsuite.transport.socket.SocketConditionalWritabilityTest;
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import java.util.List;
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public class EpollLTSocketConditionalWritabilityTest extends SocketConditionalWritabilityTest {
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@Override
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protected List<TestsuitePermutation.BootstrapComboFactory<ServerBootstrap, Bootstrap>> newFactories() {
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return EpollSocketTestPermutation.INSTANCE.socket();
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}
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@Override
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protected void configure(ServerBootstrap bootstrap, Bootstrap bootstrap2, ByteBufAllocator allocator) {
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super.configure(bootstrap, bootstrap2, allocator);
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bootstrap.option(EpollChannelOption.EPOLL_MODE, EpollMode.LEVEL_TRIGGERED)
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.childOption(EpollChannelOption.EPOLL_MODE, EpollMode.LEVEL_TRIGGERED);
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bootstrap2.option(EpollChannelOption.EPOLL_MODE, EpollMode.LEVEL_TRIGGERED);
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}
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}
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