> 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.
I have no idea what it will do on all our platforms.
> 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.
I suspect there is more benefit to be gained through actual tested
refactoring (with assumption: systrace is almost never used).
