public void Write <T>(T[] instances, Action <T> write)
{
RMonitor.Enter(_writersMutex);
try
{
var index = RInterlocked.Read(ref _index);
var nextIndex = Toggle(index);
if (WaitOnFirstWrite)
{
WaitWhileOccupied(_readIndicator[nextIndex]); // Now we're subject to starvation by (new) readers.
} // And mutual exclusion may still be violated.
_snoop.BeginWrite(nextIndex);
write(instances[nextIndex]);
_snoop.EndWrite(nextIndex);
// Move subsequent readers to 'next' instance
RInterlocked.Exchange(ref _index, nextIndex);
// Wait for all readers to finish reading the instance we want to write next
WaitWhileOccupied(_readIndicator[index]);
// At this point there may be readers, but they must be on nextReadIndex, we can
// safely write.
_snoop.BeginWrite(index);
write(instances[index]);
_snoop.EndWrite(index);
}
finally
{
RMonitor.Exit(_writersMutex);
}
}
private int GetReaderIndex()
{
if (_thisReaderIndex.IsValueCreated)
{
return(_thisReaderIndex.Value);
}
var result = RInterlocked.Increment(ref _nextReaderIndex) - 1;
_thisReaderIndex.Value = result;
return(result);
}
internal void EnterWriteLock()
{
RMonitor.Enter(_lockObj);
RUnordered.Write(ref _writerActive, 1);
RInterlocked.MemoryBarrierProcessWide();
while (ReadInProgress())
{
RE.Yield();
}
_snoop.BeginWrite();
return;
}
private void EnterSlow()
{
RMonitor.Enter(_lockObj);
RUnordered.Write(ref _holdingThreadId, Environment.CurrentManagedThreadId);
RInterlocked.MemoryBarrierProcessWide();
while (RUnordered.Read(ref _isHeld) == 1)
{
RE.Yield();
}
RUnordered.Write(ref _isHeld, 1);
RMonitor.Exit(_lockObj);
return;
}
public void Add(int v)
{
while (true)
{
var local = RVolatile.Read(ref _data);
var copy = local == null ? new List <int>() : new List <int>(local);
copy.Add(v);
if (RInterlocked.CompareExchange(ref _data, copy, local))
{
break;
}
}
}
public U Read <T, U>(T[] instances, Func <T, U> read)
{
_readIndicator.Arrive();
try
{
var idx = RInterlocked.Read(ref _readIndex);
_snoop.BeginRead(idx);
var result = read(instances[idx]);
_snoop.EndRead(idx);
return(result);
}
finally
{
_readIndicator.Depart();
}
}
private LockCookie EnterSlow()
{
RMonitor.Enter(_lockObj);
var oldEntry = RUnordered.Read(ref _current);
RUnordered.Write(ref _current, new LockCookie(Environment.CurrentManagedThreadId));
RInterlocked.MemoryBarrierProcessWide();
while (oldEntry != null && RUnordered.Read(ref oldEntry.Taken) == 1)
{
RE.Yield();
}
var current = RUnordered.Read(ref _current);
RUnordered.Write(ref current.Taken, 1);
RMonitor.Exit(_lockObj);
return(current);
}
public void Write <T>(T[] instances, Action <T> write)
{
RMonitor.Enter(_writersMutex);
try
{
// var readIndex = RUnordered.Read(ref _readIndex);
var readIndex = RInterlocked.Read(ref _readIndex);
var nextReadIndex = Toggle(readIndex);
_snoop.BeginWrite(nextReadIndex);
write(instances[nextReadIndex]);
_snoop.EndWrite(nextReadIndex);
// Move subsequent readers to 'next' instance
RInterlocked.Exchange(ref _readIndex, nextReadIndex);
// Wait for all readers marked in the 'next' read indicator,
// these readers could be reading the 'readIndex' instance
// we want to write next
var versionIndex = RInterlocked.Read(ref _versionIndex);
//var versionIndex = RUnordered.Read(ref _versionIndex);
var nextVersionIndex = Toggle(versionIndex);
WaitWhileOccupied(_readIndicator[nextVersionIndex]);
// Move subsequent readers to the 'next' read indicator
RInterlocked.Exchange(ref _versionIndex, nextVersionIndex);
// RUnordered.Write(ref _versionIndex, nextVersionIndex);
// At this point all subsequent readers will read the 'next' instance
// and mark the 'nextVersionIndex' read indicator, so the only remaining potential
// readers are the ones on the 'versionIndex' read indicator, so wait for them to finish
WaitWhileOccupied(_readIndicator[versionIndex]);
// At this point there may be readers, but they must be on nextReadIndex, we can
// safely write.
_snoop.BeginWrite(readIndex);
write(instances[readIndex]);
_snoop.EndWrite(readIndex);
}
finally
{
RMonitor.Exit(_writersMutex);
}
}
public void Write <T>(T[] instances, Action <T> write)
{
RMonitor.Enter(_writersMutex);
try
{
var readIndex = RInterlocked.Read(ref _readIndex);
var nextReadIndex = Toggle(readIndex);
_snoop.BeginWrite(nextReadIndex);
write(instances[nextReadIndex]);
_snoop.EndWrite(nextReadIndex);
RInterlocked.Exchange(ref _readIndex, nextReadIndex);
WaitWhileOccupied(_readIndicator);
_snoop.BeginWrite(readIndex);
write(instances[readIndex]);
_snoop.EndWrite(readIndex);
}
finally
{
RMonitor.Exit(_writersMutex);
}
}
public void Depart()
{
RInterlocked.Decrement(ref _numReaders);
}
public void Arrive()
{
RInterlocked.Increment(ref _numReaders);
}
public void Depart()
{
int index = GetIndex();
RInterlocked.Decrement(ref _occupancyCounts[index]);
}
public void Arrive()
{
int index = GetIndex();
RInterlocked.Increment(ref _occupancyCounts[index]);
}
