| /* |
| * 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.flink.statefun.flink.core.logger; |
| |
| import java.util.ArrayDeque; |
| import javax.annotation.Nullable; |
| import javax.annotation.concurrent.NotThreadSafe; |
| import org.apache.flink.core.memory.MemorySegment; |
| import org.apache.flink.core.memory.MemorySegmentFactory; |
| import org.apache.flink.core.memory.MemorySegmentSource; |
| |
| @NotThreadSafe |
| final class MemorySegmentPool implements MemorySegmentSource { |
| static final int PAGE_SIZE = 64 * 1024; |
| |
| private final ArrayDeque<MemorySegment> pool; |
| private final long inMemoryBufferSize; |
| private long totalAllocatedMemory; |
| |
| MemorySegmentPool(long inMemoryBufferSize) { |
| this.pool = new ArrayDeque<>(); |
| this.inMemoryBufferSize = inMemoryBufferSize; |
| } |
| |
| @Nullable |
| @Override |
| public MemorySegment nextSegment() { |
| MemorySegment segment = pool.pollFirst(); |
| if (segment != null) { |
| return segment; |
| } |
| // |
| // no segments in the pool, try to allocate one. |
| // |
| if (!hasRemainingCapacity()) { |
| return null; |
| } |
| segment = MemorySegmentFactory.allocateUnpooledSegment(PAGE_SIZE); |
| totalAllocatedMemory += PAGE_SIZE; |
| return segment; |
| } |
| |
| void release(MemorySegment segment) { |
| if (totalAllocatedMemory > inMemoryBufferSize) { |
| // |
| // we previously overdraft. |
| // |
| segment.free(); |
| totalAllocatedMemory -= PAGE_SIZE; |
| return; |
| } |
| pool.add(segment); |
| } |
| |
| int getSegmentSize() { |
| return PAGE_SIZE; |
| } |
| |
| void ensureAtLeastOneSegmentPresent() { |
| if (!pool.isEmpty()) { |
| // |
| // the next allocation would succeeded because the pool is not empty |
| // |
| return; |
| } |
| if (hasRemainingCapacity()) { |
| // |
| // the next allocation would succeeded because the total allocated size is within the allowed |
| // range |
| // |
| return; |
| } |
| // |
| // we overdraft momentarily. |
| // |
| MemorySegment segment = MemorySegmentFactory.allocateUnpooledSegment(PAGE_SIZE); |
| totalAllocatedMemory += PAGE_SIZE; |
| pool.add(segment); |
| } |
| |
| private boolean hasRemainingCapacity() { |
| return totalAllocatedMemory + PAGE_SIZE <= inMemoryBufferSize; |
| } |
| } |