Steven Rostedt writes: > So now I'm asking for advice on some ideas that can be a work around to > keep the robustness and speed. Ideally, what I'd like to do on powerpc is to dedicate one register to storing a per-cpu base address or offset, and be able to resolve the offset at link time, so that per-cpu variable accesses just become a register + offset memory access. (For modules, "link time" would be module load time.) We *might* be able to use some of the infrastructure that was put into gcc and binutils to support TLS (thread local storage) to achieve this. (See http://people.redhat.com/drepper/tls.pdf for some of the details of that.) Also, I've added Rusty Russell to the cc list, since he designed the per-cpu variable stuff in the first place, and would be able to explain the trade-offs that led to the PERCPU_ENOUGH_ROOM thing. (I think you're discovering them as you go, though. :) Paul.
