hlsf goes bad
This commit is contained in:
@@ -53,13 +53,13 @@ namespace StgSharp.HighPerformance.Memory
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Entry* entry = null;
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nuint requestedOffset = GetAllocSize(size);
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(int level, int segment) = GetIndexPairOnce(size);
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int index = (3 * level) + segment;
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int index = int.Min((3 * level) + segment, _bucketHeads.Length);
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int i = index;
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while ((i < _bucketHeads.Length) && !TryPopLevelForAllocation(index, out entry)) {
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while ((i < _bucketHeads.Length) && !TryPopLevelForAllocation(i, out entry)) {
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i++;
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}
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if ((i > _maxLevel) && !TryAllocateNewBlock(requestedOffset, out entry)) {
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throw new OverflowException("Out of memory: Unable to allocate new 16MB block or find suitable bucket for allocation.");
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if ((i >= _bucketHeads.Length) && !TryAllocateNewBlock(requestedOffset, out entry)) {
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throw new OverflowException($"Out of memory: unable to satisfy request of {size} B (aligned {requestedOffset} B) from existing buckets or spare memory.");
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}
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if (entry != null)
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{
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@@ -96,13 +96,13 @@ namespace StgSharp.HighPerformance.Memory
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Entry* entry = null;
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nuint requestedOffset = GetAllocSize(size);
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(int level, int segment) = GetIndexPairOnce(size);
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int index = (3 * level) + segment;
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int index = int.Min((3 * level) + segment, _bucketHeads.Length);
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int i = index;
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while ((i < _bucketHeads.Length) && !TryPopLevelForAllocation(index, out entry)) {
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while ((i < _bucketHeads.Length) && !TryPopLevelForAllocation(i, out entry)) {
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i++;
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}
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if ((i > _maxLevel) && !TryAllocateNewBlock(requestedOffset, out entry)) {
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throw new OverflowException("Out of memory: Unable to allocate new 16MB block or find suitable bucket for allocation.");
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if ((i >= _bucketHeads.Length) && !TryAllocateNewBlock(requestedOffset, out entry)) {
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throw new OverflowException($"Out of memory: unable to satisfy request of {size} B (aligned {requestedOffset} B) from existing buckets or spare memory.");
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}
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if (entry != null)
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@@ -138,10 +138,24 @@ namespace StgSharp.HighPerformance.Memory
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{
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Entry* next = e;
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nuint remain = sizeToSlice; // remained size to slice
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nuint offset = e->Position - sizeToSlice - ((nuint)m_Buffer); // offset of buffer to slice
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nuint end = e->Position - ((nuint)m_Buffer); // end offset of buffer to slice
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nuint offset = e->Position - sizeToSlice - ((nuint)m_Buffer); // offset of buffer to slice
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nuint position = e->Position - sizeToSlice; // position of buffer to slice
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nuint end = e->Position - ((nuint)m_Buffer); // end offset of buffer to slice
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int i = (BitOperations.TrailingZeroCount(offset) - 6) / 2;
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int i = GetBucketIndexOnce(sizeToSlice);
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Entry* entry = (Entry*)_entries.Allocate();
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SetEntryLevel(entry, position, remain);
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entry->State = EntryState.Empty;
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BucketNode* bucketNode = (BucketNode*)entry->Position;
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bucketNode->EntryRef = entry;
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PushNodeToBucket(i, bucketNode);
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Entry* prev = next->PreviousNear;
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prev->NextNear = entry;
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entry->PreviousNear = prev;
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entry->NextNear = next;
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next->PreviousNear = entry;
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}
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/// <summary>
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@@ -34,6 +34,12 @@ 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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/*
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* All operations with style of (level, segment)
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* DO NOT assume that the level are valid.
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* They are just used to calculate the bucket index,
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* which may exceed the range of _bucketHeads.
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*/
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private void PushBucketToLevel(
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@@ -46,7 +52,7 @@ namespace StgSharp.HighPerformance.Memory
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return;
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}
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int index = (3 * levelIndex) + sizeIndex;
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int index = Math.Min((3 * levelIndex) + sizeIndex, _bucketHeads.Length - 1);
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PushNodeToBucket(index, node);
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}
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@@ -55,7 +61,7 @@ namespace StgSharp.HighPerformance.Memory
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BucketNode* node
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)
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{
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index = (index >= _bucketHeads.Length) ? _bucketHeads.Length : index;
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index = Math.Min(index, _bucketHeads.Length - 1);
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if (_bucketHeads[index] is null)
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{
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_bucketHeads[index] = node;
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@@ -69,15 +75,12 @@ namespace StgSharp.HighPerformance.Memory
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{
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BucketNode* head = _bucketHeads[index];
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node->NextLevel = head;
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BucketNode* headNode = head;
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node->IsInBucket = true;
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_bucketHeads[index] = node;
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// Console.WriteLine($"Push to head of level of {levelIndex} {sizeIndex}, bucket pos {(ulong)node}, previous head is at {head}");
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if (headNode != null)
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{
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headNode->PreviousLevel = node;
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}
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head->PreviousLevel = node;
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return;
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}
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}
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@@ -89,8 +92,7 @@ namespace StgSharp.HighPerformance.Memory
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BucketNode* node
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)
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{
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int index = (3 * levelIndex) + sizeIndex;
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index = (index >= _bucketHeads.Length) ? _bucketHeads.Length : index;
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int index = Math.Min((3 * levelIndex) + sizeIndex, _bucketHeads.Length - 1);
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if (_bucketHeads[index] == node)
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{
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if (TryPopBucket(index, out _)) {
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@@ -157,8 +159,7 @@ namespace StgSharp.HighPerformance.Memory
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out BucketNode* node
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)
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{
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int index = (3 * levelIndex) + sizeIndex;
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index = (index >= _bucketHeads.Length) ? (_bucketHeads.Length - 1) : index;
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int index = int.Min((3 * levelIndex) + sizeIndex, _bucketHeads.Length - 1);
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return TryPopBucket(index, out node);
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}
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@@ -74,23 +74,25 @@ namespace StgSharp.HighPerformance.Memory
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{
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size += cur->Size;
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Entry* next = cur->NextNear;
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RemoveFromBucket(cur->Level, DetermineSegmentIndex(_levelSizeArray, cur->Size, cur->Level), (BucketNode*)cur->Position);
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RemoveFromBucket(cur->Level, GetSegmentFromLevel(cur->Size, cur->Level), (BucketNode*)cur->Position);
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RemoveFromPositionChain(cur);
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cur = next;
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} while ((cur != null) && (cur != _spareMemory) && (cur->State == EntryState.Empty));
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if (size > 0) {
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if (size > 0)
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{
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OrganizeMemory(cur, size);
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size = 0;
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}
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}
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}
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/// <summary>
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/// Free allocated memory block and perform adjacent block merging
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/// </summary>
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/// <param name="handle">
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/// Handle to the allocated memory block
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/// <param name="collectPolicy">
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/// </param>
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/// Free allocated memory block and perform adjacent block merging
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/// </summary>
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/// <param name="handle">
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/// Handle to the allocated memory block
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/// <param name="collectPolicy">
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/// </param>
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public void Free(
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HlsfHandle handle,
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FreePolicy collectPolicy = FreePolicy.NoCollect
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@@ -108,16 +110,12 @@ namespace StgSharp.HighPerformance.Memory
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e->State = EntryState.Empty;
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// Try merge with adjacent free blocks and remove them from buckets
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if (collectPolicy == FreePolicy.LazyCollect)
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{
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MergeAndRemoveFromBuckets(e);
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}
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MergeAndRemoveFromBuckets(e);
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// Calculate final level and segment for the merged block
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nuint finalSize = e->Size;
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int finalLevel = GetLevelFromSize(finalSize);
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(int finalLevel, int finalSegment) = GetIndexPairOnce(finalSize);
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e->Level = finalLevel;
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int finalSegment = DetermineSegmentIndex(_levelSizeArray, finalSize, finalLevel);
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// Push the merged entry back to appropriate bucket
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PushBucketToLevel(finalLevel, finalSegment, (BucketNode*)e->Position);
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@@ -145,16 +143,14 @@ namespace StgSharp.HighPerformance.Memory
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e->State = EntryState.Empty;
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// Try merge with adjacent free blocks and remove them from buckets
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if (collectPolicy == FreePolicy.LazyCollect)
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{
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MergeAndRemoveFromBuckets(e);
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}
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/**/
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MergeAndRemoveFromBuckets(e);
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// Calculate final level and segment for the merged block
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nuint finalSize = e->Size;
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int finalLevel = GetLevelFromSize(finalSize);
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e->Level = finalLevel;
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int finalSegment = DetermineSegmentIndex(_levelSizeArray, finalSize, finalLevel);
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int finalSegment = GetSegmentFromLevel(finalSize, finalLevel);
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// Push the merged entry back to appropriate bucket
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PushBucketToLevel(finalLevel, finalSegment, (BucketNode*)e->Position);
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@@ -62,7 +62,7 @@ namespace StgSharp.HighPerformance.Memory
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level = Math.Min(level, _maxLevel);
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uint levelSize = 1u << (log2Size & (~1));
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int segment = ((int)(size / levelSize)) - 1;
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return (level * 3) + segment;
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return Math.Min((level * 3) + segment, _bucketHeads.Length - 1);
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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@@ -82,6 +82,19 @@ namespace StgSharp.HighPerformance.Memory
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return (level, segment);
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}
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/// <summary>
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/// NOTICE: returned level may exceed maxLevel, caller is responsible for ensuring the
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/// returned level is within bounds. This method is designed for performance and does not
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/// perform bounds checking.
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/// </summary>
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/// <param name="size">
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/// Size of the memory block to determine level for. This method does not assume size is
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/// already aligned
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/// </param>
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/// <returns>
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/// Level corresponding to the given size. Level is determined based on the formula: level
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/// >= (log2(S) - 6) / 2
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/// </returns>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private int GetLevelFromSize(
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nuint size
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@@ -104,7 +117,7 @@ namespace StgSharp.HighPerformance.Memory
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int level = Math.Max(0, (log2Size - 6) / 2);
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// caller is responsible for ensuring level is within bounds
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return Math.Min(level, _maxLevel);
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return level;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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@@ -42,13 +42,12 @@ namespace StgSharp.HighPerformance.Memory
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/// </returns>
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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private static bool AssertAdjacentTo(
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Entry* current,
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Entry* other
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Entry* front,
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Entry* back
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)
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{
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// Only a predicate; never throw here. Callers rely on false to skip merging.
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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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return front->Position + front->Size == back->Position;
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}
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[MethodImpl(MethodImplOptions.AggressiveInlining)]
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@@ -83,7 +82,8 @@ namespace StgSharp.HighPerformance.Memory
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/// strategy.
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/// </summary>
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private void MergeAndRemoveFromBuckets(
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Entry* entry
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Entry* entry,
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int maxScanRange = 4
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)
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{
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if (entry == null) {
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@@ -94,7 +94,8 @@ namespace StgSharp.HighPerformance.Memory
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nuint size = entry->Size;
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int originLevel = entry->Level;
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int segment = GetSegmentFromLevel(size, originLevel);
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do
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for (int i = 0; i < maxScanRange; i++)
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{
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// previous direction merge
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Entry* p = entry->PreviousNear;
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@@ -112,9 +113,9 @@ namespace StgSharp.HighPerformance.Memory
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entry->Position = p->Position;
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RemoveFromBucket(originLevel, GetSegmentFromLevel(p->Size, originLevel), (BucketNode*)p->Position);
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RemoveFromPositionChain(p);
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} while (true);
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}
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do
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for (int i = 0; i < maxScanRange; i++)
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{
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// next direction merge
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Entry* n = entry->NextNear;
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@@ -122,7 +123,7 @@ namespace StgSharp.HighPerformance.Memory
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(n == _spareMemory) ||
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(n->State != EntryState.Empty) ||
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(n->Level != entry->Level) ||
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!AssertAdjacentTo(n, entry))
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!AssertAdjacentTo(entry, n))
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{
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break;
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}
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@@ -131,8 +132,9 @@ namespace StgSharp.HighPerformance.Memory
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entry->Size += n->Size;
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RemoveFromBucket(originLevel, GetSegmentFromLevel(n->Size, originLevel), (BucketNode*)n->Position);
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RemoveFromPositionChain(n);
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} while (true);
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originLevel = int.Min(9, originLevel);
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}
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// originLevel = int.Min(9, originLevel);
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entry->Level = GetLevelFromSize(entry->Size);
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BucketNode* bucket = (BucketNode*)entry->Position;
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@@ -39,7 +39,7 @@ namespace StgSharp.HighPerformance.Memory
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public void DebugAgeAll()
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{
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AgeAll();
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// AgeAll();
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}
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public bool DebugContains(
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@@ -109,11 +109,11 @@ namespace StgSharp.HighPerformance.Memory
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*
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* This is safe only with the current L4 allocation/layout guarantees.
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*/
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short predictCount = Volatile.Read(ref (*_predictCount)[index]);
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short mapCount = Volatile.Read(ref (*_mapCount)[index]);
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int decrement = (short.Min(predictCount, mapCount) + 1) / 2;
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_ = Interlocked.Add(ref Unsafe.As<short, int>(ref (*_predictCount)[index]), -decrement);
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_ = Interlocked.Add(ref Unsafe.As<short, int>(ref (*_mapCount)[index]), -decrement);
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int predictCount = Volatile.Read(ref (*_predictCount)[index]);
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int mapCount = Volatile.Read(ref (*_mapCount)[index]);
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int decrement = (int.Min(predictCount, mapCount) + 1) / 2;
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_ = Interlocked.Add(ref (*_predictCount)[index], -decrement);
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_ = Interlocked.Add(ref (*_mapCount)[index], -decrement);
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}
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(*_predictCount)[index]++;
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}
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@@ -56,29 +56,25 @@ namespace StgSharp.HighPerformance.Memory
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/// </exception>
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/// <remarks>
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/// <para><strong> Important Threading Considerations: </strong></para> <para> While SLAB
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/// /// /// /// allocators themselves may be designed for single-threaded use,
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/// allocated /// objects /// are /// frequently shared across multiple threads in
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/// real-world /// applications. Due to /// the /// special implementation of
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/// expandable concurrent /// sequential SLAB allocators, /// they rely /// on
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/// internal expansion locks to /// ensure that memory buffer expansions /// (which
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/// involve /// copying the entire /// buffer to a new location) do not occur while
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/// /// other threads are /// reading /// from allocated regions.</para>
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/// <para><strong> /// Sequential Layout Limitations: /// /// </strong><br />
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/// Sequential layout SLAB allocators /// cannot provide a single- /// threaded ///
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/// version because:<list /// type="bullet"><item><description> They use ///
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/// contiguous memory /// layout that requires /// buffer expansion when capacity is
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/// /// exceeded /// /// </description></item><item><description> Buffer expansion
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/// involves /// copying all /// /// existing data to a new memory /// location
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/// </description></item><item><description>/// /// Without proper ///
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/// synchronization, concurrent access to allocated objects during /// /// expansion
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/// /// would cause memory corruption </description></item><item><description> The ///
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/// /// /// expansion lock mechanism is essential even if allocation itself is
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/// single- /// /// /// threaded</description></item></list></para> <para><strong>
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/// Chunked Layout: /// /// /// </strong><br /> Chunked layout allocators can
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/// optionally provide single-threaded /// /// /// versions since they don't
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/// require buffer expansion and copying. Each /// chunk is /// /// allocated
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/// independently, avoiding the memory relocation issues /// present in ///
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/// sequential /// layouts.</para>
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/// allocators themselves may be designed for single-threaded use, allocated objects are
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/// frequently shared across multiple threads in real-world applications. Due to the
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/// special implementation of expandable concurrent sequential SLAB allocators, they rely
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/// on internal expansion locks to ensure that memory buffer expansions (which involve
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/// copying the entire buffer to a new location) do not occur while other threads are
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/// reading from allocated regions.</para> <para><strong>Sequential Layout
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/// Limitations:</strong><br /> Sequential layout SLAB allocators cannot provide a single-
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/// threaded version because:<list type="bullet"><item><description>They use contiguous
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/// memory layout that requires buffer expansion when capacity is
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/// exceeded</description></item><item><description>Buffer expansion involves copying all
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/// existing data to a new memory location</description></item><item><description> Without
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/// proper synchronization, concurrent access to allocated objects during synchronization,
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/// concurrent access to allocated objects during expansion would cause memory corruption
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/// </description></item><item><description> The expansion lock mechanism is essential
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/// even if allocation itself is single- threaded</description></item></list></para>
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/// <para><strong> Chunked Layout: </strong><br /> Chunked layout allocators can
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/// optionally provide single-threaded versions since they don't require buffer expansion
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/// and copying. Each chunk is allocated independently, avoiding the memory relocation
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/// issues present in sequential layouts.</para>
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/// </remarks>
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public static SlabAllocator<T> Create<T>(
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nuint count,
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@@ -89,12 +85,12 @@ namespace StgSharp.HighPerformance.Memory
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return layout switch
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{
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SlabBufferLayout.Sequential => concurrentSupport ?
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(new ConcurrentSequentialSlabAllocator<T>(count)) :
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(throw new NotSupportedException("Non-concurrent version of sequential layout SLAB is not supported due to expansion lock requirements for memory safety during buffer expansion.")),
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new ConcurrentSequentialSlabAllocator<T>(count) :
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throw (new NotSupportedException("Non-concurrent version of sequential layout SLAB is not supported due to expansion lock requirements for memory safety during buffer expansion.")),
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SlabBufferLayout.Chunked => concurrentSupport ?
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(new ConcurrentChunkedSlabAllocator<T>(count)) :
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(new ChunkedSlabAllocator<T>(count)),
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_ => throw new ArgumentOutOfRangeException(nameof(layout), layout, null)
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new ConcurrentChunkedSlabAllocator<T>(count) :
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new ChunkedSlabAllocator<T>(count),
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_ => throw (new ArgumentOutOfRangeException(nameof(layout), layout, null))
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};
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}
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Reference in New Issue
Block a user