+TO: x86 maintainers, ThunderX maintainers > From: Stephen Hemminger [mailto:[email protected]] > Sent: Wednesday, 29 July 2026 19.54 > > The generic and C11 lock-free stack implementations differ only in > memory ordering. The generic version uses a full barrier where its > own comments state an acquire fence is sufficient, and seq_cst for > all length counter operations. > > Only x86 and ThunderX still used the generic version. On x86 the > switch removes a locked add per CAS attempt in push and pop; TSO > provides the acquire semantics. On ThunderX the pop fence weakens > from dmb ish to dmb ishld and the push fence goes away. Unlike the > ring, no platform selected the generic stack for measured > performance reasons. > > Remove it and use the C11 implementation everywhere.
The lack of measured performance difference documentation is not a valid reason to remove the generic version! It would be reasonable to assume that x86 (and ThunderX) use the generic version for non-insignificant performance reasons. If there is no performance difference, I agree with this patch. Otherwise not. This could be verified by providing the missing measurements.
