//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="HLSFAllocator.BucketNode.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;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Threading;
namespace StgSharp.HighPerformance.Memory
{
public unsafe partial class HybridLayerSegregatedFitAllocator
{
private static void AcquireBucketNodeSpinLock(BucketNode* node)
{
int thread = Environment.CurrentManagedThreadId;
if (node != null && Volatile.Read(ref node->SpinLock) != thread)
{
while (Interlocked.CompareExchange(ref node->SpinLock, thread, 0) != 0) {
Thread.Sleep(0);
}
}
}
///
/// Initialize bucket system (called in constructor)
///
private void InitializeBucketSystem()
{
_bucketHeads = new ulong[levelSize.Length * 3];
}
private void PushLevel(int levelIndex, int sizeIndex, BucketNode* node)
{
if (node == null || node->EntryRef == null) {
return;
}
int index = (3 * levelIndex) + sizeIndex;
if (Interlocked.CompareExchange(ref _bucketHeads[index], (nuint)node, EmptyHandle) == EmptyHandle)
{
node->TrySetState(BucketNode.StateEmpty, BucketNode.StateInBucket);
node->Magic = BucketNode.MAGIC_NUMBER;
return;
} else
{
while (true)
{
AcquireBucketNodeSpinLock(node);
ulong head = Volatile.Read(ref _bucketHeads[index]);
node->NextLevel = head;
BucketNode* headNode = (BucketNode*)head;
try
{
if (Interlocked.CompareExchange(ref _bucketHeads[index], (nuint)node, head) == head)
{
if (!TryAcquireBucketNodeSpinLock(headNode))
{
// reset state and retry
_ = Interlocked.CompareExchange(ref _bucketHeads[index], head, (nuint)node);
Thread.Sleep(0);
continue;
}
try
{
node->TrySetState(BucketNode.StateEmpty, BucketNode.StateInBucket);
node->Magic = BucketNode.MAGIC_NUMBER;
headNode->PreviousLevel = (ulong)node;
return;
}
finally
{
ReleaseBucketNodeSpinLock(headNode);
}
} else
{
Thread.Sleep(0);
continue;
}
}
finally
{
ReleaseBucketNodeSpinLock(node);
}
}
}
}
private static void ReleaseBucketNodeSpinLock(BucketNode* node)
{
int thread = Environment.CurrentManagedThreadId;
if (node != null && Volatile.Read(ref node->SpinLock) != 0) {
_ = Interlocked.CompareExchange(ref node->SpinLock, 0, thread);
}
}
private void RemoveFromBucket(int levelIndex, int sizeIndex, BucketNode* node)
{
int index = (3 * levelIndex) + sizeIndex;
while (true)
{
// top of stack
if ((BucketNode*)Volatile.Read(ref _bucketHeads[index]) == node && TryAcquireBucketNodeSpinLock(node))
{
_ = TryPopLevel(levelIndex, sizeIndex, out _);
} else
{
AcquireBucketNodeSpinLock(node);
ulong p = Volatile.Read(ref node->PreviousLevel), n = Volatile.Read(ref node->NextLevel);
BucketNode* previous = (BucketNode*)p, next = (BucketNode*)n;
try
{
if (next is null)
{
// bottom of stack
if (!TryAcquireBucketNodeSpinLock(previous))
{
Thread.Sleep(0);
continue;
}
previous->NextLevel = EmptyHandle;
node->PreviousLevel = EmptyHandle;
return;
}
if (!(TryAcquireBucketNodeSpinLock(previous) && TryAcquireBucketNodeSpinLock(next)))
{
// middle of stack
Thread.Sleep(0);
continue;
}
previous ->NextLevel = n;
next->PreviousLevel = p;
node->NextLevel = EmptyHandle;
node->PreviousLevel = EmptyHandle;
return;
}
finally
{
ReleaseBucketNodeSpinLock(node);
ReleaseBucketNodeSpinLock(previous);
ReleaseBucketNodeSpinLock(next);
}
}
}
}
private static bool TryAcquireBucketNodeSpinLock(BucketNode* node)
{
int thread = Environment.CurrentManagedThreadId;
return (node == null) ||
(Interlocked.CompareExchange(ref node->SpinLock, thread,
0) == 0) ||
(Volatile.Read(ref node->SpinLock) == thread);
}
private bool TryPopLevel(int levelIndex, int sizeIndex, out BucketNode* node)
{
int index = (3 * levelIndex) + sizeIndex;
while (true)
{
ulong h = Volatile.Read(ref _bucketHeads[index]);
BucketNode* head = (BucketNode*)h;
BucketNode* next = null;
try
{
if (head == null)
{
node = null;
return false;
}
if (!TryAcquireBucketNodeSpinLock(head))
{
Thread.Sleep(0);
continue;
}
ulong n = Volatile.Read(ref head->NextLevel);
next = (BucketNode*)n;
if (!TryAcquireBucketNodeSpinLock(next))
{
Thread.Sleep(0);
continue;
}
if (Interlocked.CompareExchange(ref _bucketHeads[index], head->NextLevel, h) == h)
{
node = head;
node->TrySetState(BucketNode.StateInBucket, BucketNode.StateEmpty);
node->NextLevel = EmptyHandle;
next->PreviousLevel = EmptyHandle;
return true;
} else
{
Thread.Sleep(0);
continue;
}
}
finally
{
ReleaseBucketNodeSpinLock(head);
ReleaseBucketNodeSpinLock(next);
}
}
}
///
/// BucketNode structure - specialized node for bucket linked lists Stored in main
/// allocation area (user-overwritable region)
///
[StructLayout(LayoutKind.Explicit, Size = 36)]
internal struct BucketNode
{
public const uint MAGIC_NUMBER = 0xBEEFCAFE; // Magic number for node integrity verification
[FieldOffset(16)] internal Entry* EntryRef; // Pointer to corresponding Entry
[FieldOffset(29)] internal byte LeftOpMask; // Left pointer operation (Free=0, Occupied=1)
[FieldOffset(30)] internal byte RightOpMask; // Right pointer operation (Free=0, Occupied=1)
[FieldOffset(31)] internal byte SelfOpMask; // Self operation (Free=0, Occupied=1)
// Four independent byte masks for atomic operations
[FieldOffset(28)] internal byte StateMask; // Usage state (Empty=0, InBucket=1, MarkedForRemoval=2)
[FieldOffset(32)] internal int SpinLock; // Spin lock for bucket head operation (保留用于兼容)
[FieldOffset(24)] internal uint Magic; // Magic number verification
[FieldOffset(0)] internal ulong NextLevel; // Bucket stack linked list: next pointer
[FieldOffset(8)] internal ulong PreviousLevel; // Bucket stack linked list: previous pointer
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsNullOrEmpty(BucketNode* node)
{
return node == null || node->Magic != MAGIC_NUMBER;
}
#region Four Independent Byte Masks
// State constants
public const byte StateEmpty = 0;
public const byte StateInBucket = 1;
public const byte StateMarkedForRemoval = 2;
public const byte StateReserved = 3;
// Operation constants
public const byte OpFree = 0;
public const byte OpOccupied = 1;
// 字节级原子操作 - 使用lock-free的自旋方式
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TrySetState(byte expectedState, byte newState)
{
byte current;
do
{
current = Volatile.Read(ref StateMask);
if (current != expectedState) {
return false;
}
} while (Interlocked.CompareExchange(ref StateMask, newState, expectedState) != expectedState);
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public byte GetState() => Volatile.Read(ref StateMask);
// Left operation atomic methods
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TryAcquireLeftOp()
{
return Interlocked.CompareExchange(ref LeftOpMask, OpOccupied, OpFree) == OpFree;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void ReleaseLeftOp()
{
Volatile.Write(ref LeftOpMask, OpFree);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsLeftOpOccupied() => Volatile.Read(ref LeftOpMask) == OpOccupied;
// Right operation atomic methods
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TryAcquireRightOp()
{
return Interlocked.CompareExchange(ref RightOpMask, OpOccupied, OpFree) == OpFree;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void ReleaseRightOp()
{
Volatile.Write(ref RightOpMask, OpFree);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsRightOpOccupied() => Volatile.Read(ref RightOpMask) == OpOccupied;
// Self operation atomic methods
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TryAcquireSelfOp()
{
return Interlocked.CompareExchange(ref SelfOpMask, OpOccupied, OpFree) == OpFree;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void ReleaseSelfOp()
{
Volatile.Write(ref SelfOpMask, OpFree);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsSelfOpOccupied() => Volatile.Read(ref SelfOpMask) == OpOccupied;
// Convenience properties
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsInBucket() => GetState() == StateInBucket;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsEmpty() => GetState() == StateEmpty;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsMarkedForRemoval() => GetState() == StateMarkedForRemoval;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool HasAnyOperation() => IsLeftOpOccupied() || IsRightOpOccupied() || IsSelfOpOccupied();
#endregion
}
}
}