public virtual int CopyPage(I4KbBatchWrites destI4KbBatchWrites, int scratchNumber, long p, PagerState pagerState)
{
var item = GetScratchBufferFile(scratchNumber);
ScratchBufferFile bufferFile = item.File;
return(bufferFile.CopyPage(destI4KbBatchWrites, p, pagerState));
}
protected int CopyPageImpl(I4KbBatchWrites destwI4KbBatchWrites, long p, PagerState pagerState)
{
var src = AcquirePagePointer(null, p, pagerState);
var pageHeader = (PageHeader *)src;
int numberOfPages = 1;
if ((pageHeader->Flags & PageFlags.Overflow) == PageFlags.Overflow)
{
numberOfPages = VirtualPagerLegacyExtensions.GetNumberOfOverflowPages(pageHeader->OverflowSize);
}
const int adjustPageSize = (Constants.Storage.PageSize) / (4 * Constants.Size.Kilobyte);
destwI4KbBatchWrites.Write(pageHeader->PageNumber * (long)adjustPageSize, numberOfPages * adjustPageSize, src);
return(numberOfPages);
}
public override int CopyPage(I4KbBatchWrites destwI4KbBatchWrites, long p, PagerState pagerState)
{
return(CopyPageImpl(destwI4KbBatchWrites, p, pagerState));
}
public override int CopyPage(I4KbBatchWrites destI4KbBatchWrites, long pageNumber, PagerState pagerState)
{
long sizeToMap = AllocationGranularity;
var distanceFromStart = (pageNumber % NumberOfPagesInAllocationGranularity);
var allocationStartPosition = pageNumber - distanceFromStart;
var offset = allocationStartPosition * Constants.Storage.PageSize;
var mmflags = _copyOnWriteMode ? MmapFlags.MAP_PRIVATE : MmapFlags.MAP_SHARED;
var result = Syscall.mmap64(IntPtr.Zero, (UIntPtr)sizeToMap,
MmapProts.PROT_READ | MmapProts.PROT_WRITE,
mmflags, _fd, offset);
try
{
if (result.ToInt64() == -1) //system didn't succeed in mapping the address where we wanted
{
var err = Marshal.GetLastWin32Error();
Syscall.ThrowLastError(err,
$"Unable to map (default view size) {sizeToMap / Constants.Size.Kilobyte:#,#0} kb for page {pageNumber} starting at {allocationStartPosition} on {FileName}");
}
var pageHeader = (PageHeader *)(result.ToInt64() + distanceFromStart * Constants.Storage.PageSize);
int numberOfPages = 1;
if ((pageHeader->Flags & PageFlags.Overflow) == PageFlags.Overflow)
{
numberOfPages = VirtualPagerLegacyExtensions.GetNumberOfOverflowPages(pageHeader->OverflowSize);
}
if (numberOfPages + distanceFromStart > NumberOfPagesInAllocationGranularity)
{
Syscall.munmap(result, (UIntPtr)sizeToMap);
result = new IntPtr(-1);
sizeToMap = NearestSizeToAllocationGranularity((numberOfPages + distanceFromStart) *
Constants.Storage.PageSize);
result = Syscall.mmap64(IntPtr.Zero, (UIntPtr)sizeToMap, MmapProts.PROT_READ | MmapProts.PROT_WRITE,
mmflags, _fd, offset);
if (result.ToInt64() == -1)
{
var err = Marshal.GetLastWin32Error();
Syscall.ThrowLastError(err,
$"Unable to map {sizeToMap / Constants.Size.Kilobyte:#,#0} kb for page {pageNumber} starting at {allocationStartPosition} on {FileName}");
}
pageHeader = (PageHeader *)(result.ToInt64() + (distanceFromStart * Constants.Storage.PageSize));
}
const int adjustPageSize = (Constants.Storage.PageSize) / (4 * Constants.Size.Kilobyte);
destI4KbBatchWrites.Write(pageHeader->PageNumber * adjustPageSize, numberOfPages * adjustPageSize,
(byte *)pageHeader);
return(numberOfPages);
}
finally
{
if (result.ToInt64() != -1)
{
Syscall.munmap(result, (UIntPtr)sizeToMap);
}
}
}
public int CopyPage(I4KbBatchWrites destI4KbBatchWrites, long p, PagerState pagerState)
{
return(_scratchPager.CopyPage(destI4KbBatchWrites, p, pagerState));
}
public override int CopyPage(I4KbBatchWrites destI4KbBatchWrites, long pageNumber, PagerState pagerState)
{
var distanceFromStart = (pageNumber % NumberOfPagesInAllocationGranularity);
var allocationStartPosition = pageNumber - distanceFromStart;
var offset = new WindowsMemoryMapPager.SplitValue {
Value = (ulong)allocationStartPosition * (ulong)Constants.Storage.PageSize
};
var result = MapViewOfFileEx(_hFileMappingObject, _mmFileAccessType, offset.High,
offset.Low,
(UIntPtr)AllocationGranularity, null);
try
{
if (result == null)
{
var lastWin32Error = Marshal.GetLastWin32Error();
throw new Win32Exception($"Unable to map (default view size) {AllocationGranularity / Constants.Size.Kilobyte:#,#0} kb for page {pageNumber} starting at {allocationStartPosition} on {FileName}",
new Win32Exception(lastWin32Error));
}
var pageHeader = (PageHeader *)(result + distanceFromStart * Constants.Storage.PageSize);
int numberOfPages = 1;
if ((pageHeader->Flags & PageFlags.Overflow) == PageFlags.Overflow)
{
numberOfPages = VirtualPagerLegacyExtensions.GetNumberOfOverflowPages(pageHeader->OverflowSize);
}
if (numberOfPages + distanceFromStart > NumberOfPagesInAllocationGranularity)
{
UnmapViewOfFile(result);
result = null;
var newSize = NearestSizeToAllocationGranularity((numberOfPages + distanceFromStart) * Constants.Storage.PageSize);
result = MapViewOfFileEx(_hFileMappingObject, _mmFileAccessType, offset.High,
offset.Low,
(UIntPtr)newSize, null);
if (result == null)
{
var lastWin32Error = Marshal.GetLastWin32Error();
throw new Win32Exception($"Unable to map {newSize / Constants.Size.Kilobyte:#,#0} kb for page {pageNumber} starting at {allocationStartPosition} on {FileName}",
new Win32Exception(lastWin32Error));
}
pageHeader = (PageHeader *)(result + (distanceFromStart * Constants.Storage.PageSize));
}
const int adjustPageSize = (Constants.Storage.PageSize) / (4 * Constants.Size.Kilobyte);
destI4KbBatchWrites.Write(pageHeader->PageNumber * adjustPageSize, numberOfPages * adjustPageSize, (byte *)pageHeader);
return(numberOfPages);
}
finally
{
if (result != null)
{
UnmapViewOfFile(result);
}
}
}
public abstract int CopyPage(I4KbBatchWrites destwI4KbBatchWrites, long p, PagerState pagerState);
