On Mon, Oct 26, 2015 at 8:46 AM, Michael McConville <[email protected]> wrote:
> We have a pretty strong guarantee that it can only happen once per
> process...
...
> --- sys/sys/syscall_mi.h 9 Oct 2015 01:17:18 -0000 1.11
> +++ sys/sys/syscall_mi.h 26 Oct 2015 15:13:44 -0000
> @@ -72,7 +72,8 @@ mi_syscall(struct proc *p, register_t co
> if (lock)
> KERNEL_LOCK();
> pledged = (p->p_p->ps_flags & PS_PLEDGE);
> - if (pledged && !(tval = pledge_check(p, code))) {
> + if (__predict_false(
> + pledged && !(tval = pledge_check(p, code)))) {
I disagree. That's the code used on every syscall, not just once per
process and pledged is true for *most* of the processes on a -current
box. No, that doesn't mean we should do __predict_true() there.
In general, __predict_{true,false} should be left in the tool box and
only pulled out after detailed dives into code paths involved. For
all my banging on the project, I think I've used them in *two* places.
Philip Guenther
