| static private ThreadSleep ( int milliseconds ) : void | ||
| milliseconds | int | |
| return | void | |
public void Flush(UIntPtr capacity)
{
if (_viewHandle != null)
{
unsafe
{
byte *firstPagePtr = null;
try
{
_viewHandle.AcquirePointer(ref firstPagePtr);
bool success = Interop.mincore.FlushViewOfFile((IntPtr)firstPagePtr, capacity) != 0;
if (success)
{
return; // This will visit the finally block.
}
// It is a known issue within the NTFS transaction log system that
// causes FlushViewOfFile to intermittently fail with ERROR_LOCK_VIOLATION
// As a workaround, we catch this particular error and retry the flush operation
// a few milliseconds later. If it does not work, we give it a few more tries with
// increasing intervals. Eventually, however, we need to give up. In ad-hoc tests
// this strategy successfully flushed the view after no more than 3 retries.
int error = Marshal.GetLastWin32Error();
bool canRetry = (!success && error == Interop.mincore.Errors.ERROR_LOCK_VIOLATION);
SpinWait spinWait = new SpinWait();
for (int w = 0; canRetry && w < MaxFlushWaits; w++)
{
int pause = (1 << w); // MaxFlushRetries should never be over 30
MemoryMappedFile.ThreadSleep(pause);
for (int r = 0; canRetry && r < MaxFlushRetriesPerWait; r++)
{
success = Interop.mincore.FlushViewOfFile((IntPtr)firstPagePtr, capacity) != 0;
if (success)
{
return; // This will visit the finally block.
}
spinWait.SpinOnce();
error = Marshal.GetLastWin32Error();
canRetry = (error == Interop.mincore.Errors.ERROR_LOCK_VIOLATION);
}
}
// We got to here, so there was no success:
throw Win32Marshal.GetExceptionForWin32Error(error);
}
finally
{
if (firstPagePtr != null)
{
_viewHandle.ReleasePointer();
}
}
}
}
}