private SharedMemoryBucket CreateBucket(ref SharedMemoryBucket[] bucketFiles, BufferRef bufferRef, int bufferFileIndex, int bucketIndex)
{
SharedMemoryBucket bucket;
lock (_buckets)
{
if (bucketFiles == null)
{
bucketFiles = new SharedMemoryBucket[4];
_buckets[bufferRef.BucketIndex] = bucketFiles;
}
if (bufferFileIndex >= bucketFiles.Length)
{
var newSize = BitUtil.FindNextPositivePowerOfTwo(bufferFileIndex + 1);
var newbucketFiles = new SharedMemoryBucket[newSize];
Array.Copy(bucketFiles, 0, newbucketFiles, 0, bucketFiles.Length);
bucketFiles = newbucketFiles;
_buckets[bufferRef.BucketIndex] = newbucketFiles;
}
bucket = bucketFiles[bufferFileIndex];
if (bucket.DirectFile == null)
{
var bucketDir = Path.Combine(_directoryPath, bucketIndex.ToString());
Directory.CreateDirectory(bucketDir);
var buffersPerBucketFile = (1 << 15) >> bucketIndex;
var bufferSize = SharedMemoryPool.BucketIndexToBufferSize(bucketIndex, _pageSize);
var allocationSize = buffersPerBucketFile * bufferSize;
// Since we are using sparse files check available free space
var available = GetAvailableFreeSpace();
// 2x just in case, maybe we need to monitor this and stop any allocations everywhere when below c.200MB or 1GB to be sure
if (available >= 0 && allocationSize * 2 > available)
{
throw new NotEnoughSpaceException(true);
}
// Console.WriteLine($"allocationSize for bucket {bucketIndex}: {allocationSize}");
var df = new DirectFile(Path.Combine(bucketDir, bufferFileIndex + ".smbkt"), allocationSize, true,
FileOptions.RandomAccess // Note that we cannot use async with sparse without using valid NativeOverlapped struct in DeviceIoControl function
| FileOptions.WriteThrough, // TODO review if we need this
true);
DirectFile.PrefetchMemory(df.DirectBuffer);
Trace.TraceInformation($"Allocated new file in a bucket {bucketIndex}. Total # of files: {bucketFiles.Count(x => x.DirectFile != null)}");
bucket = new SharedMemoryBucket(df, bucketIndex, _pageSize);
// Console.WriteLine($"File capacity for bucket {bucketIndex}: {bucket.BufferCount}");
bucketFiles[bufferFileIndex] = bucket;
}
}
return(bucket);
}
public SharedMemoryBucket(DirectFile directFile, int bucketIndex, int pageSize = DefaultPageSize)
{
BufferRef.EnsureBucketIndexInRange(bucketIndex);
DirectFile = directFile;
var directBuffer = directFile.DirectBuffer;
var bufferSize = SharedMemoryPool.BucketIndexToBufferSize(bucketIndex, pageSize);
BufferCount = directBuffer.Length / bufferSize;
DirectBuffer = directBuffer;
BucketIndex = bucketIndex;
PageSize = pageSize;
BufferSize = bufferSize;
}