262 lines
9.7 KiB
Plaintext
262 lines
9.7 KiB
Plaintext
//-----------------------------------------------------------------------
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// -----------------------------------------------------------------------
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// file="HLSFAllocator.SegmentEntry.cs"
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// Project: StgSharp
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// AuthorGroup: Nitload Space
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// Copyright (c) Nitload Space. All rights reserved.
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//
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// Permission is hereby granted, free of charge, to any person
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// obtaining a copy of this software and associated documentation
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// files (the “Software”), to deal in the Software without restriction,
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// including without limitation the rights to use, copy, modify, merge,
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// publish, distribute, sublicense, and/or sell copies of the Software,
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// and to permit persons to whom the Software is furnished to do so,
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// subject to the following conditions:
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//
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// The above copyright notice and
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// this permission notice shall be included in all copies
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// or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED “AS IS”,
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// WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
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// INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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// IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
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// ARISING FROM, OUT OF OR IN CONNECTION WITH
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// THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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// -----------------------------------------------------------------------
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// -----------------------------------------------------------------------
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using System;
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using System.Linq.Expressions;
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using System.Reflection.PortableExecutable;
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using System.Runtime.CompilerServices;
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using System.Runtime.InteropServices;
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using System.Runtime.Serialization;
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using System.Threading;
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namespace StgSharp.HighPerformance.Memory
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{
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public unsafe partial class HybridLayerSegregatedFitAllocator
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{
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private static void AcquireEntrySpinLock(Entry* entry)
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{
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int thread = Environment.CurrentManagedThreadId;
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if (entry != null && Volatile.Read(ref entry->SpinLock) != thread)
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{
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while (Interlocked.CompareExchange(ref entry->SpinLock, thread, 0) != 0) {
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Thread.Sleep(0);
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}
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}
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}
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private bool AssertAlignBoundry(ulong current, Entry* target, int level)
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{
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int size = (level * 2) + 6;
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ulong align = current >> size;
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return align == target->Position >> size && align == target->Size;
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}
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/// <summary>
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/// Determine segment index based on size and originLevel
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/// </summary>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private int DetermineSegmentIndex(uint size, int level)
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{
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return (int)size / levelSize[level];
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}
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/// <summary>
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/// Check if two Entries are adjacent in memory
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/// </summary>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static bool IsAdjacentTo(Entry* current, Entry* other)
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{
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// Check if this immediately follows other
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return other->Position + other->Size == current->Position ||
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current->Position + current->Size == other->Position;
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}
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/// <summary>
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/// Used in Free operations, efficiently remove from buckets and merge adjacent blocks.
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/// Current Entry will serve as the final merged block. The Merge will be in lazy
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/// stretagey, any fail in acquiring spin lock will end a merging process.
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/// </summary>
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private void MergeAndRemoveFromBuckets(Entry* entry)
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{
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if (entry == null) {
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return;
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}
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Entry* result = entry;
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uint size = entry->Size;
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int originLevel = -1;
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int segment = DetermineSegmentIndex(size, originLevel);
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if (TryAcquireEntrySpinLock(entry)) {
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return;
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}
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// current Level merge
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while (originLevel != entry->Level)
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{
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ulong offset = entry->Position - (ulong)m_Buffer;
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AcquireBucketNodeSpinLock((BucketNode*)entry->Position);
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while (true)
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{
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ulong n = entry->NextNear;
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Entry* near = (Entry*)n;
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if (near == null ||
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near->State != EntryState.Empty ||
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!IsAdjacentTo(entry, near) ||
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entry->Level != near->Level ||
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!AssertAlignBoundry(offset, near, entry->Level) ||
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!TryAcquireEntrySpinLock(near))
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{
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break;
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}
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RemoveFromBucket(originLevel, , (BucketNode*)near->Position);
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}
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// forward merging
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while (true)
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{
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ulong n = entry->NextNear;
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Entry* near = (Entry*)n;
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if (near == null ||
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near->State != EntryState.Empty ||
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!IsAdjacentTo(entry, near) ||
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entry->Level != near->Level ||
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!AssertAlignBoundry(offset, near, entry->Level) ||
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!TryAcquireEntrySpinLock(near))
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{
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break;
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}
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}
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}
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}
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private void MergeEntry(Entry* remain, Entry* other)
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{
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if (other == null) {
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return;
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}
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// Determine merged starting position and size
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nuint newPosition = remain->Position < other->Position ? other->Position : other->Position;
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uint newSize = remain->Size + other->Size;
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// Update current Entry
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remain->Position = newPosition;
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remain->Size = newSize;
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}
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private void RecycleEntry(Entry* entry)
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{
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if (entry is null) {
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return;
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}
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entry-> PreviousNear = EmptyHandle;
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entry-> Position = EmptyHandle;
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_nodes.Free((nuint)entry);
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}
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private static void ReleaseEntrySpinLock(Entry* entry)
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{
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int thread = Environment.CurrentManagedThreadId;
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if (entry != null && Volatile.Read(ref entry->SpinLock) != 0) {
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_ = Interlocked.CompareExchange(ref entry->SpinLock, 0, thread);
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}
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}
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/// <summary>
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/// Remove node from position linked list
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/// </summary>
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private void RemoveFromPositionChain(Entry* entry)
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{
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AcquireEntrySpinLock(entry);
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try
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{
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Entry* prev = (Entry*)entry->PreviousNear;
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Entry* next = (Entry*)entry->NextNear;
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if (prev != null) {
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prev->NextNear = entry->NextNear;
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}
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if (next != null) {
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next->PreviousNear = entry->PreviousNear;
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}
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// Clear node pointers
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entry->NextNear = EmptyHandle;
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entry->PreviousNear = EmptyHandle;
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_nodes.Free((nuint)entry);
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}
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finally
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{
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ReleaseEntrySpinLock(entry);
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}
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static bool TryAcquireEntrySpinLock(Entry* entry)
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{
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int thread = Environment.CurrentManagedThreadId;
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return entry == null ||
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(Interlocked.CompareExchange(ref entry->SpinLock, thread,
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0) == 0) ||
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Volatile.Read(ref entry->SpinLock) == thread;
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}
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/// <summary>
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/// Entry structure - streamlined version (only position and state information) Stored in
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/// external SLAB
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/// </summary>
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[StructLayout(LayoutKind.Explicit, Size = 40)]
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internal struct Entry
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{
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[FieldOffset(36)] internal int Level; // Level of the block in the allocator
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[FieldOffset(24)] internal int SpinLock; // Spin lock for thread safety protection
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[FieldOffset(28)] internal int State; // Node state
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[FieldOffset(32)] internal uint Size; // Block size information
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[FieldOffset(8)] internal ulong NextNear; // Position linked list: next pointer
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[FieldOffset(16)] internal ulong PreviousNear; // Position linked list: previous pointer
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[FieldOffset(0)] public nuint Position; // Memory block position
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public static bool IsNullOrEmptyIndex(ulong index)
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{
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return index == EmptyHandle;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public static bool IsNullOrEmptyIndex(Entry* entry)
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{
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return entry == null;
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}
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/// <summary>
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/// Merge two adjacent Entries (caller must ensure they are adjacent and both Empty
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/// state)
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/// </summary>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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public void MergeWith(Entry* other) { }
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}
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private static class EntryState
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{
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public const int Allocated = 1; // Already allocated to user
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public const int Empty = 0; // Free, can be allocated
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public const int ThreadOccupied = 2; // Occupied by thread (being operated on)
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}
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}
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}
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