| // Copyright 2015 The Bazel Authors. All rights reserved. |
| // |
| // Licensed 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 com.google.devtools.build.lib.worker; |
| |
| import com.google.common.base.Throwables; |
| import com.google.common.base.VerifyException; |
| import com.google.common.collect.ImmutableMap; |
| import com.google.common.collect.ImmutableSet; |
| import java.io.IOException; |
| import java.util.LinkedHashMap; |
| import java.util.List; |
| import java.util.Map; |
| import java.util.Map.Entry; |
| import java.util.Objects; |
| import java.util.concurrent.atomic.AtomicInteger; |
| import javax.annotation.Nonnull; |
| import javax.annotation.concurrent.ThreadSafe; |
| import org.apache.commons.pool2.impl.EvictionPolicy; |
| import org.apache.commons.pool2.impl.GenericKeyedObjectPool; |
| |
| /** |
| * A worker pool that spawns multiple workers and delegates work to them. Allows separate |
| * configuration for singleplex and multiplex workers. While the configuration is per mnemonic, the |
| * actual pools need to be per WorkerKey, as different WorkerKeys may imply different process |
| * startup options. |
| * |
| * <p>This is useful when the worker cannot handle multiple parallel requests on its own and we need |
| * to pre-fork a couple of them instead. Multiplex workers <em>can</em> handle multiple parallel |
| * requests, but do so through WorkerProxy instances. |
| */ |
| @ThreadSafe |
| public class WorkerPool { |
| /** Unless otherwise specified, the max number of workers per WorkerKey. */ |
| private static final int DEFAULT_MAX_WORKERS = 4; |
| /** Unless otherwise specified, the max number of multiplex workers per WorkerKey. */ |
| private static final int DEFAULT_MAX_MULTIPLEX_WORKERS = 8; |
| |
| private static final int MAX_NON_BLOCKING_HIGH_PRIORITY_WORKERS = 1; |
| /** |
| * How many high-priority workers are currently borrowed. If greater than one, low-priority |
| * workers cannot be borrowed until the high-priority ones are done. |
| */ |
| private final AtomicInteger highPriorityWorkersInUse = new AtomicInteger(0); |
| /** Which mnemonics create high-priority workers. */ |
| private final ImmutableSet<String> highPriorityWorkerMnemonics; |
| |
| private final WorkerPoolConfig workerPoolConfig; |
| /** Map of singleplex worker pools, one per mnemonic. */ |
| private final ImmutableMap<String, SimpleWorkerPool> workerPools; |
| /** Map of multiplex worker pools, one per mnemonic. */ |
| private final ImmutableMap<String, SimpleWorkerPool> multiplexPools; |
| |
| public WorkerPool(WorkerPoolConfig workerPoolConfig) { |
| this.workerPoolConfig = workerPoolConfig; |
| |
| highPriorityWorkerMnemonics = |
| ImmutableSet.copyOf((Iterable<String>) workerPoolConfig.getHighPriorityWorkers()); |
| |
| ImmutableMap<String, Integer> config = |
| createConfigFromOptions(workerPoolConfig.getWorkerMaxInstances(), DEFAULT_MAX_WORKERS); |
| ImmutableMap<String, Integer> multiplexConfig = |
| createConfigFromOptions( |
| workerPoolConfig.getWorkerMaxMultiplexInstances(), DEFAULT_MAX_MULTIPLEX_WORKERS); |
| |
| workerPools = createWorkerPools(workerPoolConfig.getWorkerFactory(), config); |
| multiplexPools = createWorkerPools(workerPoolConfig.getWorkerFactory(), multiplexConfig); |
| } |
| |
| public WorkerPoolConfig getWorkerPoolConfig() { |
| return workerPoolConfig; |
| } |
| |
| /** |
| * Creates a configuration for a worker pool from the options given. If the same mnemonic occurs |
| * more than once in the options, the last value passed wins. |
| */ |
| @Nonnull |
| private static ImmutableMap<String, Integer> createConfigFromOptions( |
| List<Entry<String, Integer>> options, int defaultMaxWorkers) { |
| LinkedHashMap<String, Integer> newConfigBuilder = new LinkedHashMap<>(); |
| for (Map.Entry<String, Integer> entry : options) { |
| if (entry.getValue() != null) { |
| newConfigBuilder.put(entry.getKey(), entry.getValue()); |
| } else if (entry.getKey() != null) { |
| newConfigBuilder.put(entry.getKey(), defaultMaxWorkers); |
| } |
| } |
| if (!newConfigBuilder.containsKey("")) { |
| // Empty string gives the number of workers for any type of worker not explicitly specified. |
| // If no value is given, use the default. |
| newConfigBuilder.put("", defaultMaxWorkers); |
| } |
| return ImmutableMap.copyOf(newConfigBuilder); |
| } |
| |
| private static ImmutableMap<String, SimpleWorkerPool> createWorkerPools( |
| WorkerFactory factory, Map<String, Integer> config) { |
| ImmutableMap.Builder<String, SimpleWorkerPool> workerPoolsBuilder = ImmutableMap.builder(); |
| config.forEach( |
| (key, value) -> workerPoolsBuilder.put(key, new SimpleWorkerPool(factory, value))); |
| return workerPoolsBuilder.build(); |
| } |
| |
| private SimpleWorkerPool getPool(WorkerKey key) { |
| if (key.isMultiplex()) { |
| return multiplexPools.getOrDefault(key.getMnemonic(), multiplexPools.get("")); |
| } else { |
| return workerPools.getOrDefault(key.getMnemonic(), workerPools.get("")); |
| } |
| } |
| |
| public int getMaxTotalPerKey(WorkerKey key) { |
| return getPool(key).getMaxTotalPerKey(); |
| } |
| |
| public int getNumIdlePerKey(WorkerKey key) { |
| return getPool(key).getNumIdle(); |
| } |
| |
| public int getNumActive(WorkerKey key) { |
| return getPool(key).getNumActive(key); |
| } |
| |
| // TODO (b/242835648) filter throwed exceptions better |
| void evictWithPolicy(EvictionPolicy<Worker> evictionPolicy) throws InterruptedException { |
| for (SimpleWorkerPool pool : workerPools.values()) { |
| try { |
| pool.setEvictionPolicy(evictionPolicy); |
| pool.evict(); |
| } catch (Throwable t) { |
| Throwables.propagateIfPossible(t, InterruptedException.class); |
| throw new VerifyException("unexpected", t); |
| } |
| } |
| } |
| |
| /** |
| * Gets a worker. May block indefinitely if too many high-priority workers are in use and the |
| * requested worker is not high priority. |
| * |
| * @param key worker key |
| * @return a worker |
| */ |
| public Worker borrowObject(WorkerKey key) throws IOException, InterruptedException { |
| Worker result; |
| try { |
| result = getPool(key).borrowObject(key); |
| } catch (Throwable t) { |
| Throwables.propagateIfPossible(t, IOException.class, InterruptedException.class); |
| throw new RuntimeException("unexpected", t); |
| } |
| |
| // TODO(b/244297036): move highPriorityWorkerMnemonics logic to the ResourceManager. |
| if (highPriorityWorkerMnemonics.contains(key.getMnemonic())) { |
| highPriorityWorkersInUse.incrementAndGet(); |
| } else { |
| try { |
| waitForHighPriorityWorkersToFinish(); |
| } catch (InterruptedException e) { |
| returnObject(key, result); |
| throw e; |
| } |
| } |
| |
| return result; |
| } |
| |
| /** |
| * Checks if there is no blockers from high priority workers to take new worker with this worker |
| * key. Doesn't check occupancy of worker pool for this mnemonic. |
| */ |
| public boolean couldBeBorrowed(WorkerKey key) { |
| if (highPriorityWorkerMnemonics.contains(key.getMnemonic())) { |
| return true; |
| } |
| |
| if (highPriorityWorkersInUse.get() <= MAX_NON_BLOCKING_HIGH_PRIORITY_WORKERS) { |
| return true; |
| } |
| |
| return false; |
| } |
| |
| public void returnObject(WorkerKey key, Worker obj) { |
| if (highPriorityWorkerMnemonics.contains(key.getMnemonic())) { |
| decrementHighPriorityWorkerCount(); |
| } |
| getPool(key).returnObject(key, obj); |
| } |
| |
| public void invalidateObject(WorkerKey key, Worker obj) throws InterruptedException { |
| if (highPriorityWorkerMnemonics.contains(key.getMnemonic())) { |
| decrementHighPriorityWorkerCount(); |
| } |
| try { |
| getPool(key).invalidateObject(key, obj); |
| } catch (Throwable t) { |
| Throwables.propagateIfPossible(t, InterruptedException.class); |
| throw new RuntimeException("unexpected", t); |
| } |
| } |
| |
| // Decrements the high-priority workers counts and pings waiting threads if appropriate. |
| private void decrementHighPriorityWorkerCount() { |
| if (highPriorityWorkersInUse.decrementAndGet() <= MAX_NON_BLOCKING_HIGH_PRIORITY_WORKERS) { |
| synchronized (highPriorityWorkersInUse) { |
| highPriorityWorkersInUse.notifyAll(); |
| } |
| } |
| } |
| |
| // Returns once less than two high-priority workers are running. |
| private void waitForHighPriorityWorkersToFinish() throws InterruptedException { |
| // Fast path for the case where the high-priority workers feature is not in use. |
| if (highPriorityWorkerMnemonics.isEmpty()) { |
| return; |
| } |
| |
| while (highPriorityWorkersInUse.get() > MAX_NON_BLOCKING_HIGH_PRIORITY_WORKERS) { |
| synchronized (highPriorityWorkersInUse) { |
| highPriorityWorkersInUse.wait(); |
| } |
| } |
| } |
| |
| /** |
| * Closes all the worker pools, destroying the workers in the process. This waits for any |
| * currently-ongoing work to finish. |
| */ |
| public void close() { |
| workerPools.values().forEach(GenericKeyedObjectPool::close); |
| multiplexPools.values().forEach(GenericKeyedObjectPool::close); |
| } |
| |
| /** |
| * Describes the configuration of worker pool, e.g. number of maximal instances and priority of |
| * the workers. |
| */ |
| public static class WorkerPoolConfig { |
| private final WorkerFactory workerFactory; |
| private final List<Entry<String, Integer>> workerMaxInstances; |
| private final List<Entry<String, Integer>> workerMaxMultiplexInstances; |
| private final List<String> highPriorityWorkers; |
| |
| public WorkerPoolConfig( |
| WorkerFactory workerFactory, |
| List<Entry<String, Integer>> workerMaxInstances, |
| List<Entry<String, Integer>> workerMaxMultiplexInstances, |
| List<String> highPriorityWorkers) { |
| this.workerFactory = workerFactory; |
| this.workerMaxInstances = workerMaxInstances; |
| this.workerMaxMultiplexInstances = workerMaxMultiplexInstances; |
| this.highPriorityWorkers = highPriorityWorkers; |
| } |
| |
| public WorkerFactory getWorkerFactory() { |
| return workerFactory; |
| } |
| |
| public List<Entry<String, Integer>> getWorkerMaxInstances() { |
| return workerMaxInstances; |
| } |
| |
| public List<Entry<String, Integer>> getWorkerMaxMultiplexInstances() { |
| return workerMaxMultiplexInstances; |
| } |
| |
| public List<String> getHighPriorityWorkers() { |
| return highPriorityWorkers; |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) { |
| return true; |
| } |
| if (!(o instanceof WorkerPoolConfig)) { |
| return false; |
| } |
| WorkerPoolConfig that = (WorkerPoolConfig) o; |
| return workerFactory.equals(that.workerFactory) |
| && workerMaxInstances.equals(that.workerMaxInstances) |
| && workerMaxMultiplexInstances.equals(that.workerMaxMultiplexInstances) |
| && highPriorityWorkers.equals(that.highPriorityWorkers); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash( |
| workerFactory, workerMaxInstances, workerMaxMultiplexInstances, highPriorityWorkers); |
| } |
| } |
| } |