Repository: netty/netty
File: buffer/src/main/java/io/netty/buffer/AdaptivePoolingAllocator.java (Java)

Code before:
            int newLocalSize = localFreeList.size();
            if (!STATE.compareAndSet(this, previousLocalSize, newLocalSize)) {
                // State was concurrently changed by another external releaseSegment that deallocated.
                return;
            }
            // Check if all segments have been returned.
            int totalFreeSegments = newLocalSize + externalFreeList.size();
            if (totalFreeSegments == segments) {
                if (STATE.compareAndSet(this, newLocalSize, DEALLOCATED)) {
                    deallocate();
                }
            }
        }

        @Override
        void markToDeallocate() {
            IntStack localFreeList = this.localFreeList;
            int localSize = localFreeList != null ? localFreeList.size() : 0;
            STATE.set(this, localSize);
            // Check if all segments have already been returned.
            int totalFreeSegments = localSize + externalFreeList.size();
            if (totalFreeSegments == segments) {
                if (STATE.compareAndSet(this, localSize, DEALLOCATED)) {
                    deallocate();
                }
            }
        }
    }

    private static final class BuddyChunk extends Chunk implements IntConsumer {
        private static final int MIN_BUDDY_SIZE = 32768;
        private static final byte IS_CLAIMED = (byte) (1 << 7);
        private static final byte HAS_CLAIMED_CHILDREN = 1 << 6;
        private static final byte SHIFT_MASK = ~(IS_CLAIMED | HAS_CLAIMED_CHILDREN);
        private static final int PACK_OFFSET_MASK = 0xFFFF;
        private static final int PACK_SIZE_SHIFT = Integer.SIZE - Integer.numberOfLeadingZeros(PACK_OFFSET_MASK);

        private final MpscIntQueue freeList;
        // The bits of each buddy: [1: is claimed][1: has claimed children][30: MIN_BUDDY_SIZE shift to get size]
        private final byte[] buddies;
        private final int freeListCapacity;

        BuddyChunk(AbstractByteBuf delegate, Magazine magazine) {
            super(delegate, magazine, true);
            int capacity = delegate.capacity();
            int capFactor = capacity / MIN_BUDDY_SIZE;
            int tree = (capFactor << 1) - 1;
            int maxShift = Integer.numberOfTrailingZeros(capFactor);
            assert maxShift <= 30; // The top 2 bits are used for marking.
            freeListCapacity = tree >> 1;
            freeList = MpscIntQueue.create(freeListCapacity, -1); // At most half of tree (all leaf nodes) can be freed.

Review comment (suggestion):
```suggestion
            deallocateIfNeeded(localSize);
```

Code after:
        void markToDeallocate() {
            IntStack localFreeList = this.localFreeList;
            int localSize = localFreeList != null ? localFreeList.size() : 0;
            STATE.set(this, localSize);
            deallocateIfNeeded(localSize);
        }
    }

    private static final class BuddyChunk extends Chunk implements IntConsumer {
        private static final int MIN_BUDDY_SIZE = 32768;
        private static final byte IS_CLAIMED = (byte) (1 << 7);
        private static final byte HAS_CLAIMED_CHILDREN = 1 << 6;
        private static final byte SHIFT_MASK = ~(IS_CLAIMED | HAS_CLAIMED_CHILDREN);
        private static final int PACK_OFFSET_MASK = 0xFFFF;
        private static final int PACK_SIZE_SHIFT = Integer.SIZE - Integer.numberOfLeadingZeros(PACK_OFFSET_MASK);

        private final MpscIntQueue freeList;
        // The bits of each buddy: [1: is claimed][1: has claimed children][30: MIN_BUDDY_SIZE shift to get size]
        private final byte[] buddies;
        private final int freeListCapacity;

        BuddyChunk(AbstractByteBuf delegate, Magazine magazine) {
            super(delegate, magazine, true);
            freeListCapacity = delegate.capacity() / MIN_BUDDY_SIZE;
            int maxShift = Integer.numberOfTrailingZeros(freeListCapacity);
            assert maxShift <= 30; // The top 2 bits are used for marking.
            freeList = MpscIntQueue.create(freeListCapacity, -1); // At most half of tree (all leaf nodes) can be freed.
            buddies = new byte[freeListCapacity << 1];

            // Generate the buddies entries.
            int index = 1;
            int runLength = 1;
            int currentRun = 0;
            while (maxShift > 0) {
                buddies[index++] = (byte) maxShift;
                if (++currentRun == runLength) {
                    currentRun = 0;
                    runLength <<= 1;
                    maxShift--;
                }
            }
        }

        @Override
        public boolean readInitInto(AdaptiveByteBuf buf, int size, int startingCapacity, int maxCapacity) {
            if (!freeList.isEmpty()) {
                freeList.drain(freeListCapacity, this);
            }
            int startIndex = chooseFirstFreeBuddy(1, startingCapacity, 0);
            if (startIndex == -1) {
                return false;