| /* |
| * 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.geode.internal.cache.eviction; |
| |
| import java.util.Optional; |
| |
| import org.apache.logging.log4j.Logger; |
| |
| import org.apache.geode.internal.lang.SystemPropertyHelper; |
| import org.apache.geode.internal.logging.log4j.LogMarker; |
| import org.apache.geode.logging.internal.log4j.api.LogService; |
| |
| public class LRUListWithSyncSorting extends AbstractEvictionList { |
| |
| private static final Logger logger = LogService.getLogger(); |
| |
| private final int maxEntries; |
| |
| public LRUListWithSyncSorting(EvictionController controller) { |
| super(controller); |
| this.maxEntries = readMaxEntriesProperty(); |
| } |
| |
| private int readMaxEntriesProperty() { |
| int result = -1; |
| Optional<Integer> optionalMaxEntries = SystemPropertyHelper |
| .getProductIntegerProperty(SystemPropertyHelper.EVICTION_SEARCH_MAX_ENTRIES); |
| if (optionalMaxEntries.isPresent()) { |
| result = optionalMaxEntries.get(); |
| } |
| return result; |
| } |
| |
| /** |
| * return the Entry that is considered least recently used. The entry will no longer be in the |
| * pipe (unless it is the last empty marker). |
| */ |
| @Override |
| public EvictableEntry getEvictableEntry() { |
| long numEvals = 0; |
| |
| for (;;) { |
| EvictionNode aNode = this.unlinkHeadEntry(); |
| |
| if (logger.isTraceEnabled(LogMarker.LRU_CLOCK_VERBOSE)) { |
| logger.trace(LogMarker.LRU_CLOCK_VERBOSE, "lru considering {}", aNode); |
| } |
| |
| if (aNode == null) { // hit the end of the list |
| getStatistics().incEvaluations(numEvals); |
| return null; |
| } |
| |
| numEvals++; |
| |
| if (!isEvictable(aNode)) { |
| continue; |
| } |
| |
| // At this point we have any acceptable entry. Now |
| // use various criteria to determine if it's good enough |
| // to return, or if we need to add it back to the list. |
| if (maxEntries > 0 && numEvals > maxEntries) { |
| if (logger.isTraceEnabled(LogMarker.LRU_CLOCK_VERBOSE)) { |
| logger.trace(LogMarker.LRU_CLOCK_VERBOSE, "greedily picking an available entry"); |
| } |
| getStatistics().incGreedyReturns(1); |
| // fall through, return this node |
| } else if (aNode.isRecentlyUsed()) { |
| if (logger.isTraceEnabled(LogMarker.LRU_CLOCK_VERBOSE)) { |
| logger.trace(LogMarker.LRU_CLOCK_VERBOSE, "skipping recently used entry {}", aNode); |
| } |
| aNode.unsetRecentlyUsed(); |
| appendEntry(aNode); |
| continue; // keep looking |
| } else { |
| if (logger.isTraceEnabled(LogMarker.LRU_CLOCK_VERBOSE)) { |
| logger.trace(LogMarker.LRU_CLOCK_VERBOSE, "returning unused entry: {}", aNode); |
| } |
| // fall through, return this node |
| } |
| |
| // Return the current node. |
| getStatistics().incEvaluations(numEvals); |
| return (EvictableEntry) aNode; |
| } // synchronized |
| } // for |
| |
| @Override |
| public void incrementRecentlyUsed() { |
| // nothing needed |
| } |
| } |