I don’t follow. Fragmentation wasn’t the problem here - it’s that an optimization to trying to reuse the underlying allocation resulted in a severe over-allocat

I don’t follow. Fragmentation wasn’t the problem here - it’s that an optimization to trying to reuse the underlying allocation resulted in a severe over-allocation in a specific path. That would happen even with your idea unless you use DONTNEED to release all the unused pages. I think fragmentation is an over focused on problem when in practice it’s rarely the problem. It’s also a problem that can be solved by an application reset and making sure to periodically reset your running application in a way that doesn’t result in severe disruption is a better practice that works around many more issues than just fragmentation.