private static ImmixChunkHeader *AllocateChunk()
{
var chunkMemPtr = (nint)mi_malloc_aligned_at(
(nuint)ImmixConstants.TotalChunkSize,
ImmixConstants.BlockSize,
(nuint)ImmixConstants.ChunkMetadataSize);
// Assign the chunk header.
var chunkPtr = (ImmixChunkHeader *)chunkMemPtr;
chunkPtr->Initialize(totalChunks);
// Initialize the blocks.
var lineMapsStart = (byte *)chunkMemPtr + sizeof(ImmixChunkHeader);
for (var i = 0; i < ImmixConstants.BlocksPerChunk; i++)
{
*ImmixChunkHeader.GetBlock(chunkPtr, i).Header = new ImmixBlockHeader(i, lineMapsStart + (ImmixConstants.LinesCount * i));
}
// Add the chunk to the lists and increment the total chunks counter.
// TODO: Add these by address order.
chunks.Add(chunkPtr);
freeChunks.Add(totalChunks);
Interlocked.Increment(ref totalChunks);
return(chunkPtr);
}
internal static ImmixBlockAddress GetBlock()
{
ImmixBlockAddress block = null;
lock (chunks) {
if (freeChunks.Count > 0)
{
var chunkIdx = freeChunks [0];
var chunk = chunks [chunkIdx].Address;
Debug.Assert(chunk->FreeBlocks > 0);
for (var blockIdx = 0; blockIdx < ImmixConstants.BlocksPerChunk; blockIdx++)
{
if (chunk->BlockUsed [blockIdx] != 0)
{
continue;
}
block = ImmixChunkHeader.GetBlock(chunk, blockIdx);
chunk->BlockUsed [blockIdx] = 0xFF;
break;
}
Debug.Assert(block.Header != null, "Free chunks list contains a full chunk.");
if (--chunk->FreeBlocks < 1)
{
freeChunks.RemoveAt(0);
}
}
else
{
var newChunk = AllocateChunk();
newChunk->BlockUsed [0] = 0xFF;
newChunk->FreeBlocks--;
block = ImmixChunkHeader.GetBlock(newChunk, 0);
}
}
if (block.Header->UsageLevel != ImmixBlockUsage.Empty)
{
block.Header->UsageLevel = ImmixBlockUsage.Empty;
block.Header->LineMapSpan.Clear();
}
return(block);
}
