private void MoveBinAssigment(MachineWithBinAssigments oldMachine, MachineWithBinAssigments?newMachine, uint binToMove, MachineWithBinAssigments?machineToResort)
{
if (machineToResort != null)
{
// Remove the machine to re-sort before any modifications
_machineAssignmentsSortedByBinCount.Remove(machineToResort);
}
// Remove bin from old machine
oldMachine.BinsAssignedTo.Remove(binToMove);
// Add bin to new machine is specified
if (newMachine != null)
{
newMachine.BinsAssignedTo.Add(binToMove);
_binToMachineMap[binToMove] = newMachine.MachineId;
}
if (machineToResort != null)
{
// Remove the machine to resort after modifications
_machineAssignmentsSortedByBinCount.Add(machineToResort);
}
// Accesses to the machine hash set (_machineSetBuffer) are not thread safe.
foreach (var impactedBin in GetImpactedBins(binToMove, oldMachine.MachineId))
{
// Mark the old assignment as expired
_expiredAssignments.GetOrAdd(impactedBin, bin => new Dictionary <MachineId, DateTime>())[oldMachine.MachineId] = _clock.UtcNow + _expiryTime;
}
// Invalidate bins
_bins = null;
}
public BinManager(int locationsPerBin, IEnumerable <MachineId> startLocations, IClock clock, TimeSpan expiryTime)
{
LocationsPerBin = locationsPerBin;
_clock = clock;
_expiryTime = expiryTime;
_binToMachineMap = new MachineId?[NumberOfBins];
if (startLocations.Any())
{
foreach (var location in startLocations)
{
var assignments = new MachineWithBinAssigments(location);
_machineAssignmentsSortedByBinCount.Add(assignments);
_machinesToBinsMap[location] = assignments;
}
for (uint i = 0; i < NumberOfBins; i++)
{
var min = _machineAssignmentsSortedByBinCount.Min !;
_machineAssignmentsSortedByBinCount.Remove(min);
min.BinsAssignedTo.Add(i);
_machineAssignmentsSortedByBinCount.Add(min);
_binToMachineMap[i] = min.MachineId;
}
}
}
public void AddLocation(MachineId id)
{
lock (_lockObject)
{
var addedMachine = new MachineWithBinAssigments(id);
if (!_machinesToBinsMap.TryAdd(id, addedMachine))
{
// Machine already registered. Nothing to do.
return;
}
// If only one machine is registered, assign that machine to all bins
if (_machinesToBinsMap.Count == 1)
{
for (uint binNumber = 0; binNumber < NumberOfBins; binNumber++)
{
_binToMachineMap[binNumber] = id;
addedMachine.BinsAssignedTo.Add(binNumber);
}
_machinesToBinsMap[id] = addedMachine;
_machineAssignmentsSortedByBinCount.Add(addedMachine);
return;
}
// While the added machine's number of bins is less the the per machine bin count,
// move bins from machines with greatest number of assigned bins
while (addedMachine.BinsAssignedTo.Count < _machineAssignmentsSortedByBinCount.Max !.BinsAssignedTo.Count - 1)
{
var machineWithMaxNumOfBins = _machineAssignmentsSortedByBinCount.Max !;
var binToReassign = machineWithMaxNumOfBins.BinsAssignedTo.First();
// Reassign bin from machine with most number of bin assigned to the added machine
MoveBinAssigment(oldMachine: machineWithMaxNumOfBins, newMachine: addedMachine, binToMove: binToReassign, machineToResort: machineWithMaxNumOfBins);
}
_machinesToBinsMap[id] = addedMachine;
_machineAssignmentsSortedByBinCount.Add(addedMachine);
}
}
