//-----------------------------------------------------------------------
// -----------------------------------------------------------------------
// file="HLSFAllocator.SegmentEntry.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.Linq.Expressions;
using System.Reflection.PortableExecutable;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
using System.Runtime.Serialization;
using System.Threading;
namespace StgSharp.HighPerformance.Memory
{
public unsafe partial class HybridLayerSegregatedFitAllocator
{
private static void AcquireEntrySpinLock(Entry* entry)
{
// 使用新的双锁设计，获取两个锁
if (entry != null)
{
entry->AcquirePrevLock();
entry->AcquireNextLock();
}
}
private bool AssertAlignBoundry(ulong current, Entry* target, int level)
{
int size = (level * 2) + 6;
ulong align = current >> size;
return align == target->Position >> size && align == target->Size;
}
///
/// Determine segment index based on size and originLevel
///
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private int DetermineSegmentIndex(uint size, int level)
{
return (int)size / levelSize[level];
}
///
/// Check if two Entries are adjacent in memory
///
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool IsAdjacentTo(Entry* current, Entry* other)
{
// Check if this immediately follows other
return other->Position + other->Size == current->Position ||
current->Position + current->Size == other->Position;
}
///
/// Used in Free operations, efficiently remove from buckets and merge adjacent blocks.
/// Current Entry will serve as the final merged block. The Merge will be in lazy
/// stretagey, any fail in acquiring spin lock will end a merging process.
///
private Entry* MergeAndRemoveFromBuckets(Entry* entry)
{
if (entry == null) {
return null;
}
Entry* result = entry;
uint size = entry->Size;
int originLevel = GetLevelFromSize(size);
int segment = DetermineSegmentIndex(size, originLevel);
if (!TryAcquireEntrySpinLock(entry))
{
return entry; // 无法获取锁，返回原Entry
}
try
{
// 设置状态为合并中
entry->TrySetState(EntryState.Empty, EntryState.Merging);
// current Level merge
while (originLevel <= entry->Level)
{
ulong offset = entry->Position - (ulong)m_Buffer;
// backward merging - 向前合并
while (true)
{
ulong p = entry->PreviousNear;
Entry* prev = (Entry*)p;
if (prev == null ||
prev->GetState() != EntryState.Empty ||
!IsAdjacentTo(entry, prev) ||
entry->Level != prev->Level ||
!AssertAlignBoundry(offset, prev, entry->Level) ||
!TryAcquireEntrySpinLock(prev))
{
break;
}
try
{
RemoveFromBucket(originLevel, segment, (BucketNode*)prev->Position);
MergeEntry(entry, prev);
RecycleEntry(prev);
}
finally
{
ReleaseEntrySpinLock(prev);
}
}
// forward merging - 向后合并
while (true)
{
ulong n = entry->NextNear;
Entry* next = (Entry*)n;
if (next == null ||
next->GetState() != EntryState.Empty ||
!IsAdjacentTo(entry, next) ||
entry->Level != next->Level ||
!AssertAlignBoundry(offset, next, entry->Level) ||
!TryAcquireEntrySpinLock(next))
{
break;
}
try
{
RemoveFromBucket(originLevel, segment, (BucketNode*)next->Position);
MergeEntry(entry, next);
RecycleEntry(next);
}
finally
{
ReleaseEntrySpinLock(next);
}
}
// 更新level信息
originLevel++;
if (originLevel > entry->Level)
{
break;
}
}
// 恢复状态为空
entry->TrySetState(EntryState.Merging, EntryState.Empty);
return entry;
}
finally
{
ReleaseEntrySpinLock(entry);
}
}
private void MergeEntry(Entry* remain, Entry* other)
{
if (other == null) {
return;
}
// Determine merged starting position and size
nuint newPosition = remain->Position < other->Position ? other->Position : other->Position;
uint newSize = remain->Size + other->Size;
// Update current Entry
remain->Position = newPosition;
remain->Size = newSize;
}
private void RecycleEntry(Entry* entry)
{
if (entry is null) {
return;
}
entry-> PreviousNear = EmptyHandle;
entry-> Position = EmptyHandle;
_nodes.Free((nuint)entry);
}
private static void ReleaseEntrySpinLock(Entry* entry)
{
// 使用新的双锁设计，释放两个锁
if (entry != null)
{
entry->ReleaseBothLocks();
}
}
///
/// Remove node from position linked list
///
private void RemoveFromPositionChain(Entry* entry)
{
AcquireEntrySpinLock(entry);
try
{
Entry* prev = (Entry*)entry->PreviousNear;
Entry* next = (Entry*)entry->NextNear;
if (prev != null) {
prev->NextNear = entry->NextNear;
}
if (next != null) {
next->PreviousNear = entry->PreviousNear;
}
// Clear node pointers
entry->NextNear = EmptyHandle;
entry->PreviousNear = EmptyHandle;
_nodes.Free((nuint)entry);
}
finally
{
ReleaseEntrySpinLock(entry);
}
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
private static bool TryAcquireEntrySpinLock(Entry* entry)
{
// 使用新的双锁设计，尝试获取两个锁
return entry == null || entry->TryAcquireBothLocks();
}
///
/// Entry structure - streamlined version (only position and state information) Stored in
/// external SLAB
///
[StructLayout(LayoutKind.Explicit, Size = 40)]
internal struct Entry
{
[FieldOffset(26)] internal byte NextOpMask; // Next pointer operation (Free=0, Occupied=1)
[FieldOffset(25)] internal byte PrevOpMask; // Previous pointer operation (Free=0, Occupied=1)
[FieldOffset(27)] internal byte SelfOpMask; // Self operation (Free=0, Occupied=1)
// Four independent byte masks for atomic operations (replacing SpinLock)
[FieldOffset(24)] internal byte StateMask; // Entry state (Empty=0, Allocated=1, ThreadOccupied=2, Merging=3)
[FieldOffset(28)] internal int _reserved; // Reserved for future use
[FieldOffset(36)] internal int Level; // Level of the block in the allocator
[FieldOffset(32)] internal uint Size; // Block size information
[FieldOffset(8)] internal ulong NextNear; // Position linked list: next pointer
[FieldOffset(16)] internal ulong PreviousNear; // Position linked list: previous pointer
[FieldOffset(0)] public nuint Position; // Memory block position
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsNullOrEmptyIndex(ulong index)
{
return index == EmptyHandle;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public static bool IsNullOrEmptyIndex(Entry* entry)
{
return entry == null;
}
///
/// Merge two adjacent Entries (caller must ensure they are adjacent and both Empty
/// state)
///
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void MergeWith(Entry* other) { }
#region Four Independent Byte Masks for Entry
// State constants
public const byte StateEmpty = 0;
public const byte StateAllocated = 1;
public const byte StateThreadOccupied = 2;
public const byte StateMerging = 3;
// Operation constants
public const byte OpFree = 0;
public const byte OpOccupied = 1;
// 字节级原子操作 - 使用简单的volatile操作（调用者自觉模式）
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TrySetState(byte expectedState, byte newState)
{
byte current = Volatile.Read(ref StateMask);
if (current != expectedState) {
return false;
}
Volatile.Write(ref StateMask, newState);
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public byte GetState() => Volatile.Read(ref StateMask);
// Previous operation atomic methods
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TryAcquirePrevOp()
{
byte current = Volatile.Read(ref PrevOpMask);
if (current != OpFree) {
return false;
}
Volatile.Write(ref PrevOpMask, OpOccupied);
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void ReleasePrevOp()
{
Volatile.Write(ref PrevOpMask, OpFree);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsPrevOpOccupied() => Volatile.Read(ref PrevOpMask) == OpOccupied;
// Next operation atomic methods
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TryAcquireNextOp()
{
byte current = Volatile.Read(ref NextOpMask);
if (current != OpFree) {
return false;
}
Volatile.Write(ref NextOpMask, OpOccupied);
return true;
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void ReleaseNextOp()
{
Volatile.Write(ref NextOpMask, OpFree);
}
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsNextOpOccupied() => Volatile.Read(ref NextOpMask) == OpOccupied;
// Self operation atomic methods
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool TryAcquireSelfOp()
{
byte current = Volatile.Read(ref SelfOpMask);
if (current != OpFree) {
return false;
}
Volatile.Write(ref SelfOpMask, OpOccupied);
return true;
}
[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 IsEmpty() => GetState() == StateEmpty;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsAllocated() => GetState() == StateAllocated;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsThreadOccupied() => GetState() == StateThreadOccupied;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool IsMerging() => GetState() == StateMerging;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public bool HasAnyOperation() => IsPrevOpOccupied() || IsNextOpOccupied() || IsSelfOpOccupied();
#endregion
}
// 更新后的EntryState常量类 - 与新的字节掩码设计兼容
private static class EntryState
{
public const byte Allocated = 1; // Already allocated to user
public const byte Empty = 0; // Free, can be allocated
public const byte Merging = 3; // Currently being merged
public const byte ThreadOccupied = 2; // Occupied by thread (being operated on)
}
}
}