magibney commented on code in PR #13570: URL: https://github.com/apache/lucene/pull/13570#discussion_r1677916943
########## lucene/core/src/java21/org/apache/lucene/store/RefCountedSharedArena.java: ########## @@ -0,0 +1,102 @@ +/* + * 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.lucene.store; + +import java.lang.foreign.Arena; +import java.lang.foreign.MemorySegment; +import java.util.concurrent.atomic.AtomicInteger; + +@SuppressWarnings("preview") +final class RefCountedSharedArena implements Arena { + + static final int OPEN = 0; + static final int CLOSED = -1; + + private final String segmentName; + private final Runnable removeFromMap; + private final Arena arena; + + AtomicInteger state; + + RefCountedSharedArena(String segmentName, Runnable removeFromMap) { + this.segmentName = segmentName; + this.removeFromMap = removeFromMap; + this.arena = Arena.ofShared(); + this.state = new AtomicInteger(OPEN); + } + + // for debugging + String getSegmentName() { + return segmentName; + } + + boolean acquire() { + int value; + while (true) { + value = state.get(); + if (value < OPEN) { + return false; + } + if (state.compareAndSet(value, value + 1)) { + return true; + } + } + } + + void release() { + int value; + while (true) { + value = state.get(); + if (value <= OPEN) { + throw new IllegalStateException("already closed"); + } + if (state.compareAndSet(value, value - 1)) { Review Comment: Outer CAS could be replaced by `decrementAndGet()`, removing the need for a `while` loop? ########## lucene/core/src/java21/org/apache/lucene/store/RefCountedSharedArena.java: ########## @@ -0,0 +1,102 @@ +/* + * 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.lucene.store; + +import java.lang.foreign.Arena; +import java.lang.foreign.MemorySegment; +import java.util.concurrent.atomic.AtomicInteger; + +@SuppressWarnings("preview") +final class RefCountedSharedArena implements Arena { + + static final int OPEN = 0; + static final int CLOSED = -1; + + private final String segmentName; + private final Runnable removeFromMap; + private final Arena arena; + + AtomicInteger state; Review Comment: any reason for `state` to not be `final`? -- 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: issues-unsubscr...@lucene.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@lucene.apache.org For additional commands, e-mail: issues-h...@lucene.apache.org
