I'm about to commit the SMP vmspace sharing patch (the %fs approach). All kernel modules will need to be recompiled. Recompilation is not neccessary for user land applications including ps, libkvm and friends.
In this %fs approach, per-processor private pages are no longer mapped at identical virtual address for each cpu, instead a new segment descriptor (%fs) is setup to access per-cpu global variables like curproc. As a result the %fs register needs to be saved and restored at the kernel boundary, this would impose a small penalty (cpu model dependent) for each syscall and interrupt. UP kernel will also be affected as efforts were made to ensure portability of kernel modules between UP and SMP architectures. Fast vfork is now possible for SMP and is turned on as default. We're also able to get rid of vmspace juggling kludges in aio code, aio should now work correctly on SMP. -lq To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message
