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-rw-r--r--src/mscorlib/corefx/System/Buffers/ConfigurableArrayPool.cs265
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diff --git a/src/mscorlib/corefx/System/Buffers/ConfigurableArrayPool.cs b/src/mscorlib/corefx/System/Buffers/ConfigurableArrayPool.cs
deleted file mode 100644
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--- a/src/mscorlib/corefx/System/Buffers/ConfigurableArrayPool.cs
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@@ -1,265 +0,0 @@
-// Licensed to the .NET Foundation under one or more agreements.
-// The .NET Foundation licenses this file to you under the MIT license.
-// See the LICENSE file in the project root for more information.
-
-using System.Diagnostics;
-using System.Threading;
-
-namespace System.Buffers
-{
- internal sealed partial class ConfigurableArrayPool<T> : ArrayPool<T>
- {
- /// <summary>The default maximum length of each array in the pool (2^20).</summary>
- private const int DefaultMaxArrayLength = 1024 * 1024;
- /// <summary>The default maximum number of arrays per bucket that are available for rent.</summary>
- private const int DefaultMaxNumberOfArraysPerBucket = 50;
-
- private readonly Bucket[] _buckets;
-
- internal ConfigurableArrayPool() : this(DefaultMaxArrayLength, DefaultMaxNumberOfArraysPerBucket)
- {
- }
-
- internal ConfigurableArrayPool(int maxArrayLength, int maxArraysPerBucket)
- {
- if (maxArrayLength <= 0)
- {
- throw new ArgumentOutOfRangeException(nameof(maxArrayLength));
- }
- if (maxArraysPerBucket <= 0)
- {
- throw new ArgumentOutOfRangeException(nameof(maxArraysPerBucket));
- }
-
- // Our bucketing algorithm has a min length of 2^4 and a max length of 2^30.
- // Constrain the actual max used to those values.
- const int MinimumArrayLength = 0x10, MaximumArrayLength = 0x40000000;
- if (maxArrayLength > MaximumArrayLength)
- {
- maxArrayLength = MaximumArrayLength;
- }
- else if (maxArrayLength < MinimumArrayLength)
- {
- maxArrayLength = MinimumArrayLength;
- }
-
- // Create the buckets.
- int poolId = Id;
- int maxBuckets = Utilities.SelectBucketIndex(maxArrayLength);
- var buckets = new Bucket[maxBuckets + 1];
- for (int i = 0; i < buckets.Length; i++)
- {
- buckets[i] = new Bucket(Utilities.GetMaxSizeForBucket(i), maxArraysPerBucket, poolId);
- }
- _buckets = buckets;
- }
-
- /// <summary>Gets an ID for the pool to use with events.</summary>
- private int Id => GetHashCode();
-
- public override T[] Rent(int minimumLength)
- {
- // Arrays can't be smaller than zero. We allow requesting zero-length arrays (even though
- // pooling such an array isn't valuable) as it's a valid length array, and we want the pool
- // to be usable in general instead of using `new`, even for computed lengths.
- if (minimumLength < 0)
- {
- throw new ArgumentOutOfRangeException(nameof(minimumLength));
- }
- else if (minimumLength == 0)
- {
- // No need for events with the empty array. Our pool is effectively infinite
- // and we'll never allocate for rents and never store for returns.
- return Array.Empty<T>();
- }
-
- var log = ArrayPoolEventSource.Log;
- T[] buffer = null;
-
- int index = Utilities.SelectBucketIndex(minimumLength);
- if (index < _buckets.Length)
- {
- // Search for an array starting at the 'index' bucket. If the bucket is empty, bump up to the
- // next higher bucket and try that one, but only try at most a few buckets.
- const int MaxBucketsToTry = 2;
- int i = index;
- do
- {
- // Attempt to rent from the bucket. If we get a buffer from it, return it.
- buffer = _buckets[i].Rent();
- if (buffer != null)
- {
- if (log.IsEnabled())
- {
- log.BufferRented(buffer.GetHashCode(), buffer.Length, Id, _buckets[i].Id);
- }
- return buffer;
- }
- }
- while (++i < _buckets.Length && i != index + MaxBucketsToTry);
-
- // The pool was exhausted for this buffer size. Allocate a new buffer with a size corresponding
- // to the appropriate bucket.
- buffer = new T[_buckets[index]._bufferLength];
- }
- else
- {
- // The request was for a size too large for the pool. Allocate an array of exactly the requested length.
- // When it's returned to the pool, we'll simply throw it away.
- buffer = new T[minimumLength];
- }
-
- if (log.IsEnabled())
- {
- int bufferId = buffer.GetHashCode(), bucketId = -1; // no bucket for an on-demand allocated buffer
- log.BufferRented(bufferId, buffer.Length, Id, bucketId);
- log.BufferAllocated(bufferId, buffer.Length, Id, bucketId, index >= _buckets.Length ?
- ArrayPoolEventSource.BufferAllocatedReason.OverMaximumSize : ArrayPoolEventSource.BufferAllocatedReason.PoolExhausted);
- }
-
- return buffer;
- }
-
- public override void Return(T[] array, bool clearArray = false)
- {
- if (array == null)
- {
- throw new ArgumentNullException(nameof(array));
- }
- else if (array.Length == 0)
- {
- // Ignore empty arrays. When a zero-length array is rented, we return a singleton
- // rather than actually taking a buffer out of the lowest bucket.
- return;
- }
-
- // Determine with what bucket this array length is associated
- int bucket = Utilities.SelectBucketIndex(array.Length);
-
- // If we can tell that the buffer was allocated, drop it. Otherwise, check if we have space in the pool
- if (bucket < _buckets.Length)
- {
- // Clear the array if the user requests
- if (clearArray)
- {
- Array.Clear(array, 0, array.Length);
- }
-
- // Return the buffer to its bucket. In the future, we might consider having Return return false
- // instead of dropping a bucket, in which case we could try to return to a lower-sized bucket,
- // just as how in Rent we allow renting from a higher-sized bucket.
- _buckets[bucket].Return(array);
- }
-
- // Log that the buffer was returned
- var log = ArrayPoolEventSource.Log;
- if (log.IsEnabled())
- {
- log.BufferReturned(array.GetHashCode(), array.Length, Id);
- }
- }
-
- /// <summary>Provides a thread-safe bucket containing buffers that can be Rent'd and Return'd.</summary>
- private sealed class Bucket
- {
- internal readonly int _bufferLength;
- private readonly T[][] _buffers;
- private readonly int _poolId;
-
- private SpinLock _lock; // do not make this readonly; it's a mutable struct
- private int _index;
-
- /// <summary>
- /// Creates the pool with numberOfBuffers arrays where each buffer is of bufferLength length.
- /// </summary>
- internal Bucket(int bufferLength, int numberOfBuffers, int poolId)
- {
- _lock = new SpinLock(Debugger.IsAttached); // only enable thread tracking if debugger is attached; it adds non-trivial overheads to Enter/Exit
- _buffers = new T[numberOfBuffers][];
- _bufferLength = bufferLength;
- _poolId = poolId;
- }
-
- /// <summary>Gets an ID for the bucket to use with events.</summary>
- internal int Id => GetHashCode();
-
- /// <summary>Takes an array from the bucket. If the bucket is empty, returns null.</summary>
- internal T[] Rent()
- {
- T[][] buffers = _buffers;
- T[] buffer = null;
-
- // While holding the lock, grab whatever is at the next available index and
- // update the index. We do as little work as possible while holding the spin
- // lock to minimize contention with other threads. The try/finally is
- // necessary to properly handle thread aborts on platforms which have them.
- bool lockTaken = false, allocateBuffer = false;
- try
- {
- _lock.Enter(ref lockTaken);
-
- if (_index < buffers.Length)
- {
- buffer = buffers[_index];
- buffers[_index++] = null;
- allocateBuffer = buffer == null;
- }
- }
- finally
- {
- if (lockTaken) _lock.Exit(false);
- }
-
- // While we were holding the lock, we grabbed whatever was at the next available index, if
- // there was one. If we tried and if we got back null, that means we hadn't yet allocated
- // for that slot, in which case we should do so now.
- if (allocateBuffer)
- {
- buffer = new T[_bufferLength];
-
- var log = ArrayPoolEventSource.Log;
- if (log.IsEnabled())
- {
- log.BufferAllocated(buffer.GetHashCode(), _bufferLength, _poolId, Id,
- ArrayPoolEventSource.BufferAllocatedReason.Pooled);
- }
- }
-
- return buffer;
- }
-
- /// <summary>
- /// Attempts to return the buffer to the bucket. If successful, the buffer will be stored
- /// in the bucket and true will be returned; otherwise, the buffer won't be stored, and false
- /// will be returned.
- /// </summary>
- internal void Return(T[] array)
- {
- // Check to see if the buffer is the correct size for this bucket
- if (array.Length != _bufferLength)
- {
- throw new ArgumentException(SR.ArgumentException_BufferNotFromPool, nameof(array));
- }
-
- // While holding the spin lock, if there's room available in the bucket,
- // put the buffer into the next available slot. Otherwise, we just drop it.
- // The try/finally is necessary to properly handle thread aborts on platforms
- // which have them.
- bool lockTaken = false;
- try
- {
- _lock.Enter(ref lockTaken);
-
- if (_index != 0)
- {
- _buffers[--_index] = array;
- }
- }
- finally
- {
- if (lockTaken) _lock.Exit(false);
- }
- }
- }
- }
-}