public MemoryChunkBuilder ReserveAligned(ulong length)
{
var necessaryOffset = MemoryAlignmentHelper.RequiredOffset(0, AllocationSize, length);
AllocationSize += length + necessaryOffset;
return(this);
}
/// <summary>
/// Reserves part of the memory region for an array of the specififed type and length.
/// The part reserved will be aligned on a <see cref="PageAlignmentBytes"/> byte boundary.
/// </summary>
/// <typeparam name="T">The type of the array elements.</typeparam>
/// <param name="length">The count of items in the array.</param>
/// <returns>A pointer to the first item in the array.</returns>
public unsafe T *GetArrayAligned <T>(ulong length)
where T : unmanaged
{
var lengthInBytes = (ulong)Unsafe.SizeOf <T>() * length;
var necessaryOffset = MemoryAlignmentHelper.RequiredOffset((ulong)_ptr, _offset, length);
Debug.Assert(_offset + lengthInBytes + necessaryOffset <= _bytesReserved);
var result = (T *)((byte *)_ptr + _offset + necessaryOffset);
_offset += lengthInBytes + necessaryOffset;
return(result);
}
public LargePageMemoryChunk(ulong length)
{
const MemoryAllocationType flags = MemoryAllocationType.MemReserve | MemoryAllocationType.MemCommit;
const string lockMemory = "SeLockMemoryPrivilege";
_bytesReserved = MemoryAlignmentHelper.LargePageMultiple(length);
try
{
using var privs = PrivilegeHolder.EnablePrivilege(lockMemory);
if (privs != null)
{
const MemoryAllocationType largeFlag = flags | MemoryAllocationType.MemLargePages;
_ptr = NativeMethods.VirtualAlloc(IntPtr.Zero, (IntPtr)_bytesReserved, largeFlag, MemoryProtectionConstants.PageReadwrite);
GC.KeepAlive(privs);
}
}
catch (ObjectDisposedException)
{
// TODO: fix the underlying cause
}
_ptr = NativeMethods.VirtualAlloc(IntPtr.Zero, (IntPtr)_bytesReserved, flags, MemoryProtectionConstants.PageReadwrite);
}