120 lines
5.7 KiB
C#
120 lines
5.7 KiB
C#
//-----------------------------------------------------------------------
|
|
// -----------------------------------------------------------------------
|
|
// file="SlabAllocator.cs"
|
|
// Project: StgSharp
|
|
// AuthorGroup: Nitload Space
|
|
// Copyright (c) Nitload Space. All rights reserved.
|
|
//
|
|
// Permission is hereby granted, free of charge, to any person
|
|
// obtaining a copy of this software and associated documentation
|
|
// files (the “Software”), to deal in the Software without restriction,
|
|
// including without limitation the rights to use, copy, modify, merge,
|
|
// publish, distribute, sublicense, and/or sell copies of the Software,
|
|
// and to permit persons to whom the Software is furnished to do so,
|
|
// subject to the following conditions:
|
|
//
|
|
// The above copyright notice and
|
|
// this permission notice shall be included in all copies
|
|
// or substantial portions of the Software.
|
|
//
|
|
// THE SOFTWARE IS PROVIDED “AS IS”,
|
|
// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
|
|
// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
|
|
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
|
|
// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
|
|
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
|
|
// ARISING FROM, OUT OF OR IN CONNECTION WITH
|
|
// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
|
|
//
|
|
// -----------------------------------------------------------------------
|
|
// -----------------------------------------------------------------------
|
|
using System;
|
|
|
|
namespace StgSharp.HighPerformance.Memory
|
|
{
|
|
public abstract class SlabAllocator<T> : IDisposable where T: unmanaged
|
|
{
|
|
|
|
public abstract nuint Allocate();
|
|
|
|
/// <summary>
|
|
/// Creates a new SLAB allocator instance with the specified configuration.
|
|
/// </summary>
|
|
/// <param name="count">
|
|
/// Initial number of objects that can be allocated.
|
|
/// </param>
|
|
/// <param name="layout">
|
|
/// Memory layout strategy for the SLAB allocator.
|
|
/// </param>
|
|
/// <param name="concurrentSupport">
|
|
/// Whether to enable concurrent access support.
|
|
/// </param>
|
|
/// <returns>
|
|
/// A new SLAB allocator instance.
|
|
/// </returns>
|
|
/// <exception cref="ArgumentOutOfRangeException">
|
|
/// Thrown when an invalid layout is specified.
|
|
/// </exception>
|
|
/// <exception cref="NotSupportedException">
|
|
/// Thrown when requesting unsupported configurations.
|
|
/// </exception>
|
|
/// <remarks>
|
|
/// <para><strong> Important Threading Considerations: </strong></para> <para> While SLAB
|
|
/// allocators themselves may be designed for single-threaded use, allocated objects are
|
|
/// frequently shared across multiple threads in real-world applications. Due to the
|
|
/// special implementation of expandable concurrent sequential SLAB allocators, they rely
|
|
/// on internal expansion locks to ensure that memory buffer expansions (which involve
|
|
/// copying the entire buffer to a new location) do not occur while other threads are
|
|
/// reading from allocated regions.</para> <para><strong> Sequential Layout Limitations:
|
|
/// </strong><br /> Sequential layout SLAB allocators cannot provide a single-threaded
|
|
/// version because:<list type="bullet"><item><description> They use contiguous memory
|
|
/// layout that requires buffer expansion when capacity is exceeded
|
|
/// </description></item><item><description> Buffer expansion involves copying all
|
|
/// existing data to a new memory location </description></item><item><description>
|
|
/// Without proper synchronization, concurrent access to allocated objects during
|
|
/// expansion would cause memory corruption </description></item><item><description> The
|
|
/// expansion lock mechanism is essential even if allocation itself is single-threaded
|
|
/// </description></item></list></para> <para><strong> Chunked Layout: </strong><br />
|
|
/// Chunked layout allocators can optionally provide single-threaded versions since they
|
|
/// don't require buffer expansion and copying. Each chunk is allocated independently,
|
|
/// avoiding the memory relocation issues present in sequential layouts.</para>
|
|
/// </remarks>
|
|
public static SlabAllocator<T> Create(nuint count, SlabBufferLayout layout, bool concurrentSupport = true)
|
|
{
|
|
if (concurrentSupport) {
|
|
return layout switch
|
|
{
|
|
SlabBufferLayout.Sequential => new ConcurrentSequentialSlabAllocator<T>(count),
|
|
SlabBufferLayout.Chunked => new ConcurrentChunkedSlabAllocator<T>(count),
|
|
_ => throw new ArgumentOutOfRangeException(nameof(layout), layout, null)
|
|
};
|
|
}
|
|
return layout switch
|
|
{
|
|
SlabBufferLayout.Sequential => throw new NotSupportedException("Non-concurrent version of sequential layout SLAB is not supported due to expansion lock requirements for memory safety during buffer expansion."),
|
|
SlabBufferLayout.Chunked => new ChunkedSlabAllocator<T>(count),
|
|
_ => throw new ArgumentOutOfRangeException(nameof(layout), layout, null)
|
|
};
|
|
}
|
|
|
|
public abstract void Dispose();
|
|
|
|
public abstract void EnterBufferReading();
|
|
|
|
public abstract void ExitBufferReading();
|
|
|
|
public abstract void Free(nuint index);
|
|
|
|
public abstract SlabAllocationHandle<T> ReadAllocation();
|
|
|
|
}
|
|
|
|
public enum SlabBufferLayout
|
|
{
|
|
|
|
Sequential,
|
|
Chunked
|
|
|
|
}
|
|
}
|