On Mon Jun 8, 2026 at 7:34 PM CEST, Christian König wrote: > That's why we need the RCU grace period to make sure that nobody is > referencing the driver stuff any more.
Right, and that's what Philipp tries to address, the requirement to wait for an RCU grace period is perfectly fine if it is only about freeing memory, but it can become painful if the fence private data contains data also needs to be destructed in some way. IOW, if a driver signals a fence, it is lifecycle-wise reasonable to destruct the private data that is no longer needed (remaining users only deal with struct dma_fence) and having to wait for a full grace period adds sublety and complication that can be avoided with the proposed approach. That said, I'd like to ask the opposite question: What are the concerns with the proposed approach over (pure) RCU?
